Role of MicroRNAs in Plant and Animal

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microRNA在中医药防治中风中的研究进展

microRNA在中医药防治中风中的研究进展索庆芳;王筠;赵海苹;梁媛【摘要】中风的发病率正在逐年上升,具有高致残率、高病死率、高复发率的特征.小RNA(microRNA,miRNA)是一类长度为19 ～ 22个核苷酸的非编码小分子RNA,参与了神经系统的生理功能及病理改变,它们与其靶基因共同参与内皮机能障碍、神经与血管的异常调节、炎症、细胞凋亡和细胞外基质重塑等导致中风的重要环节.目前随着对miRNA研究的深入,发现miRNA与中医药防治中风的关系密切.故从microRNA与中风中医病因、中医病机、中医药治疗的关系3个方面系统阐述了miRNA在中医药防治中风研究领域中的应用.【期刊名称】《中国中医基础医学杂志》【年(卷),期】2015(021)010【总页数】2页(P1330-1331)【关键词】microRNA;防治;中风;研究进展【作者】索庆芳;王筠;赵海苹;梁媛【作者单位】北京王府中西医结合医院,北京 100049;中国中医科学院中医基础理论研究所,北京 100700;首都医科大学宣武医院,北京 100053;中国中医科学院中医基础理论研究所,北京 100700【正文语种】中文【中图分类】R255.2脑卒中是一类严重危害人类健康和生命安全的难治性疾病，具有高致残率、高病死率、高复发率的特征，发病率逐年上升［1］。

脑卒中属于中医“中风”范畴，中医药在防治中风方面有其自己独特的、传统的理论与方法。

微小RNA(microRNA，miRNA)是真核生物中一类长度为19～22个核苷酸的参与基因转录后水平调控的非编码小分子 RNA［2］。

microRNA与神经系统的生理功能及病理改变密切相关，已经成为中风病诊断、预防和治疗的重要工具［3］。

对microRNA的深入研究有可能突破中风的中医药现代研究瓶颈，为中医药防治中风提供新的思路和方法。

自唐宋以前的倡导“外风”立论，到金元时代突出以“内风”立论，到明清至近代对中风病因学的认识渐趋全面，中风的中医学病因在各种认知中逐渐完善。

简述miRNA和其在动、植物中的不同

简述miRNA及其在动、植物中的不同生命科学学院遗传系董贤欣072023032 摘要：mi RNA，是一段超级短的非编码RNA序列，长度约为20 －23 个核苷酸。

miRNA通过与靶mRNA的互补配对而在转录、转录后和翻译水平上对基因的表达进行负调控，致使mRNA 的降解或翻译抑制,进而对多种生物学进程起调控作用。

在植物和动物中，miRNA 执行这种调控作用的机理却不尽相同。

同时miRNA 在动植物体内的形成进程也存在很多的不同的地方。

本文综述了miRNA的大体特点及其在动植物中的不同。

关键词：微小RNA；动、植物；不同Abstract：MicroRNA, is a very small section of non-coding RNA sequence with about 22-23 nucleotides length. MiRNA function as sequence-specific negative regulators in transcriptional、post-transcriptional translational gene silencing by base pairing with target mRNAs, which leadsto mRNA cleavage or translational repression. This can regulate several biological processes. Meantime，there are also many differences in the biogenesis of miRNAs in plants and animals. This review highlights the basic character of miRNA and the differences of miRNA in plants and animals.Key words：miRNA, animal and plant ,differences作为Science 2002年十大科技冲破的第一名—miRNA 已成为生物学研究的一大核心，miRNA由内源性基因编码, 可通过诱导mRNA的切割降解, 翻译抑制或其他形式的调剂机制抑制靶基因的表达.它在生物的发育时序调控和疾病的发生中起到超级重要的作用。

动物植物微生物在生物圈中的作用

动物植物微生物在生物圈中的作用英文回答：Animals, plants, and microorganisms play crucial rolesin the biosphere. They contribute to the balance and functioning of ecosystems, as well as provide various benefits to human beings.Animals, as consumers, play a vital role in energy transfer and nutrient cycling within ecosystems. For example, herbivores consume plants, which helps controlplant populations and maintain ecosystem balance. Predators, on the other hand, regulate the populations of herbivores, preventing overgrazing and maintaining biodiversity. In addition, animals also aid in pollination, seed dispersal, and decomposition, all of which are essential processes for the reproduction and survival of plants.Plants, as primary producers, are the foundation offood chains and provide energy for other organisms. Theyuse sunlight to convert carbon dioxide and water into glucose through photosynthesis. This process not only produces oxygen, but also forms the basis of the food web. Plants also help in soil formation and erosion control, as their roots hold the soil together, preventing it from being washed away by water or blown away by wind.Microorganisms, although often overlooked, are incredibly important in the biosphere. They have diverse roles in nutrient cycling, decomposition, and symbiotic relationships. For example, certain bacteria and fungi break down organic matter, releasing nutrients back into the soil. This process is essential for the growth of plants and the overall health of ecosystems. Additionally, microorganisms form symbiotic relationships with plants, such as mycorrhizal fungi that help plants absorb nutrients from the soil. Some microorganisms are also involved in nitrogen fixation, converting atmospheric nitrogen into a form that can be used by plants.In conclusion, animals, plants, and microorganisms all play crucial roles in the biosphere. They contribute toenergy transfer, nutrient cycling, and ecosystem balance. Without them, the biosphere would not be able to function properly, and the survival of many species, including humans, would be at risk.中文回答：动物、植物和微生物在生物圈中扮演着至关重要的角色。

淋巴细胞

Carcinogenesis vol.33no.3pp.661–669,2012doi:10.1093/carcin/bgr320Advance Access publication January4,2012Hypoxia-inducible factor-1a inhibition by a pyrrolopyrazine metabolite of oltipraz as a consequence of microRNAs199a-5p and20a inductionSeul Gi Kang1,2,y,Woo Hyung Lee1,2,y,Young Hun Lee3, Yong Sup Lee3and Sang Geon Kim1,2,Ã1Department of Pharmacy,College of Pharmacy and2Research Institute of Pharmaceutical Sciences,Seoul National University,Seoul151-742,South Korea and3Department of Pharmaceutical Science,College of Pharmacy, Kyung Hee University,Hoegi-Dong,Seoul130-701,South KoreaÃTo whom correspondence should be addressed.College of Pharmacy,Seoul National University,Sillim-dong,Kwanak-gu,Seoul151-742,South Korea. Tel:þ822-880-7840;Fax:þ822-872-1795;Email:sgk@snu.ac.krOltipraz,a cancer chemopreventive agent,has antitumor and anti-angiogenic effects.In animal models and clinical studies,a consider-able amount of oltipraz is metabolized to pyrrolopyrazines, including M2,7-methyl-6,8-bis(methylthio)pyrrolo[1,2-a]pyrazine; M3,7-methyl-8-(methylsulﬁnyl)-6-(methylthio)pyrrolo[1,2-a]pyra-zine and M4,7-methyl-6,8-bis(methylsulﬁnyl)pyrrolo[1,2-a]pyra-zine.In view of the role of hypoxia-inducible factor-1(HIF-1)a in tumor growth and angiogenesis,this study investigated whether pyrrolopyrazine metabolites of oltipraz inhibit HIF-1a induction, and if so,what the molecular basis is.M2treatment inhibited the induction of HIF-1a by a variety of stimuli including insulin, hypoxia,CoCl2and hydrogen peroxide in HCT116cells,whereas M3or M4failed to do so.Consistently,M2prevented HIF-1a target gene induction.Moreover,it inhibited cancer cell invasion and migration.M2caused no change in the expression of HIF-1a transcript but increased the levels of precursor forms of micro-RNAs(miRNAs)199a-5p and20a,but not those of primary forms, indicating facilitation of the maturation process of the miRNAs by M2.Increased levels of the miRNAs contributed to HIF-1a re-pression,as shown by the results of experiments using mimics. Consistently,M2treatment inhibited de novo synthesis of HIF-1a, as supported by decreased incorporation of[35S]-methionine into HIF-1a with no changes in its ubiquitination or degradation. 7-Ethyl-6,8-bis(methylthio)pyrrolo[1,2-a]pyrazine,a synthetic analog of M2,had a similar inhibitory effect.In conclusion,M2 with pyrrolopyrazine structure and its7-ethyl congenor have the ability to prevent the induction of HIF-1a,which may result from the inhibition of HIF-1a de novo synthesis,as mediated by the induction of miR-199a-5p and miR-20a.IntroductionAn activated complex of hypoxia-inducible factor-1(HIF-1)a facil-itates to induce the expression of the genes implicated in the adapta-tion of cancer cells to tumor microenvironments where the utilization of oxygen and nutrients are signiﬁcantly restricted(1–3),which plays a crucial role in cancer cell proliferation,angiogenesis and invasion/ migration(4,5).Moreover,a considerable amount of HIF-1a is de-tected in aggressive and/or malignant cancers(6,7).A series of com-pounds(e.g.rapamycin,YC-1,resveratrol,radicicol and17-AAG) have been unveiled as the inhibitors of HIF-1a(4,5,8,9).Since they may possess toxic and/or adverse effects(5,9),recent pharmacolog-ical interventions in the activity of HIF-1a are limited.Thus,advances are required in the development of tailor-made inhibitors of HIF-1a.Oltipraz[4-methyl-5-(2-pyrazinyl)-1,2-dithiole-3-thione]is a can-cer chemopreventive agent(10–12)and exerts antitumor and anti-neoangiogenic effects in tumor xenograft animal models(13,14).It has an inhibitory effect on the growth of pulmonary adenomas and forestomach cancers(15,16).In mammals,oltipraz is metabolized into oxidized forms via main pathways:ﬁrst,oxidative desulfuration of the thione to yield4-methyl-5-(pyrazin-2-yl)-3H-1,2-dithiol-3-one (M1)with no further metabolism and second,desulfuration,methyl-ation and molecular rearrangement to produce7-methyl-6,8-bis(me-thylthio)pyrrolo[1,2-a]pyrazine(M2,a pyrrolopyrazine structure), which may be further metabolized to other forms(M3and M4) (17,18).In our clinical trials,oltipraz underwent prompt and substan-tial molecular conversion into mostly M2after oral administration in human(19).At a high dose(i.e.90mg,q.d.),extended residence time of oltipraz in the body may have caused increased formation of M2(19).Ourﬁndings indicated that oltipraz or its synthetic derivatives have the ability to inhibit the induction of HIF-1a in human colon cancer cells by not only facilitating its degradation but also decreasing its de novo synthesis(14).It is noteworthy that oltipraz and M2share sim-ilar pharmacokinetic proﬁles,suggesting that the M2metabolite is highly likely to contribute to the beneﬁcial effect of oltipraz and serve as the bioactive metabolite.In addition,both M1and M2induce the expression of GSTA2gene,prevent mitochondrial injury by activating adenosine monophosphate-activated protein kinase and protect hep-atocytes from reactive oxygen species(20,21).M2treatment effec-tively activated NF-E2-related factor2,suggesting that it may be pharmacologically active(20).Some NF-E2-related factor2activa-tors have the ability to inhibit the expression of HIF-1a.For example, sulforaphane and resveratrol inhibit HIF-1a activity by reducing its stability(22,23).Nonetheless,it remains to be established whether M2has an effect on HIF-1a.In view of the possibility that M2inhibits HIF-1a and has antican-cer potential,this study examined the effects of M2and its synthetic congenors on the expression and activity of HIF-1a.We also explored whether M2suppresses HIF-1a-dependent gene transactivation and,if so,the underlying basis.Here,we identiﬁed the induction of speciﬁc microRNAs(miRNAs)by M2treatment and their inhibitory effect on the translation of HIF-1a.Moreover,new derivatives of M2that have pyrrolopyrazine structure were synthesized with the aim of discover-ing other candidates that similarly inhibit HIF-1a.Now,we report the inhibitory efﬁcacy of M2and its7-ethyl substitute on the induction of HIF-1a.Ourﬁndings indicate that these agents increase the levels of mature miR-199a-5p and miR-20a for HIF-1a repression,which is a unique and novel mechanism for the inhibition of HIF-1a activity by pharmacological means.Materials and methodsCells and cell culture conditionsHCT116and HT29cells,human colon cancer cell lines,were obtained from ATCC(Rockville,MD).The cells were maintained in growth medium con-taining Dulbecco’s modiﬁed Eagle’s medium,10%fetal bovine serum and5% penicillin–streptomycin at37°C in a humidiﬁed atmosphere containing5% CO2.For all experiments,cells were grown to80–90%conﬂuency and were deprived of serum for16h before drug treatment.To create hypoxic conditions, they were transferred to a hypoxic chamber(Forma Scientiﬁc,Marietta,OH), where the cells were maintained at37°C in an atmosphere containing5%CO2, 1%O2and94%N2.MaterialsInsulin,H2O2,MG132and CoCl2were purchased from Sigma–Aldrich (St Louis,MO).Antibodies speciﬁcally directed against HIF-1a and HIF-1b were obtained from BD Biosciences Pharmingen(San Jose,CA).Anti-ubiquitin antibody was supplied from Sigma–Aldrich.Antibodies recognizingAbbreviations:HIF-1,hypoxia-inducible factor-1;miRNA,microRNA;mRNA,messenger RNA;S6K1,p70ribosomal S6kinase1;UTR,untranslatedregion.y These authors contributed equally to this work.ÓThe Author2012.Published by Oxford University Press.All rights reserved.For Permissions,please email:journals.permissions@661 at Shanghai Jiao Tong University on March 27, 2012 / Downloaded fromp70ribosomal S6kinase1(p70S6K1),p-p70S6K1,lamin A/C and HSP70 were obtained from Cell Signaling Technology(Beverly,MA).Chemical synthesis of M2and congeners1)Synthesis of6,8-bis(methylthio)-7-phenylpyrrolo[1,2-a]pyrazine(N3a)at Shanghai Jiao Tong University on March 27, 2012/Downloaded fromChromosomal DNA was precipitated with trichloroacetic acid and extracted with a solution containing0.5%SDS and0.5N NaOH.The radioactivity was measured using a liquid scintillation counter.In vitro cell invasion/migration assaysAn in vitro cell invasion/migration assay was performed using a24-well TranswellÒas described previously.The lower side of theﬁlter was covered with type I collagen,whereas its upper side was coated with Matrigel(Collaborative Research,Lexington,KY).The lower compartment was occupied with serum-free media with0.1%bovine serum albumin.HCT116cells were located in the upper compartment of the TranswellÒplate,maintained with10%serum for24h with vehicle or M2,ﬁxed with methanol and then were stained with he-matoxylin for10min,brieﬂy followed by eosin staining.The invasive phenotype was determined by quantifying the cells that migrated to the lower side of theﬁlter with microscopy(magniﬁcation,Â200). Thirteen visualﬁelds were counted for eachﬁlter,and each sample was assayed in triplicate.An in vitro cell migration assay was per-formed using a24-well TranswellÒunit with polycarbonateﬁlters. Experimental procedures were the same as for the cell invasion assay but that theﬁlter was not coated with Matrigel.Data analysisOne-way analysis of variance procedures were used to assess signiﬁcant differences among treatment groups.For each signiﬁcant treatment effect, the Newman–Keuls test was utilized to compare multiple group means.ResultsInhibition of HIF-1a and its target gene inductionInsulin treatment induces HIF-1a through both de novo synthesis and protein stabilization(26,27).First,we investigated whether the oxi-dized metabolites of oltipraz inhibit HIF-1a induction by insulin in HCT116cells.Previously,oltipraz treatment at10or30l M sup-pressed the induction of HIF-1a(14).Treatment of the cells with M2inhibited HIF-1a induction,whereas M3,M4or M1failed to do so(Figure1B).M2at30l M completely inhibited the induction of HIF-1a,beginning from1h at least up to6h,and exhibited a dose–response effect(Figure1C).The inhibitory effect of M2on HIF-1a was con-ﬁrmed in another cell line(HT29).In addition,M2had an inhibitory effect on HIF-1a induction by other stimuli including hypoxia,CoCl2 or H2O2in HCT116cells(Figure1D).HIF-1a exists as a full length with826amino acids(28).The expression of a shorter form of HIF-1a is observed presumably because alternative splicing produces the smaller form of HIF-1a(735aa)with a weak activity(28).HIF-1a forms a heterodimer with its binding subunit HIF-1b, which undergoes nuclear translocation for target gene induction (3,29).Nuclear HIF-1a content was assessed in HCT116cells treated with M2in the presence or absence of insulin.M2treatment almost completely prevented the ability of insulin to elevate nuclear HIF-1a content in either HCT116or HT29cells(Figure2A).Consistently, M2abrogated increases in HIF-1a target gene transcript levels(i.e. vascular endothelial growth factor and glucose transporter1) (Figure2B).Moreover,the results of hypoxia-response element re-porter gene assays conﬁrmed the inhibitory effect of M2on HIF-1a-dependent gene transcription(Figure2C).Fig.1.M2inhibition of HIF-1a induction by insulin.(A)The chemical structures of oltipraz and its pyrrolopyrazine metabolites.(B)The effects of oltipraz’s metabolites on the induction of HIF-1a by insulin.HCT116cells were treated with each metabolite or oltipraz(30l M each)for1h and continuously incubated in a medium containing100nM insulin for6h.(C)The time course and concentration–response effects of M2.HCT116or HT29cells were treated with30l M M2for 1–6h(left).They were also exposed to the indicated concentration of M2for6h(middle).The band intensity of HIF-1a relative to HIF-1b was quantiﬁed by scanning densitometry of the immunoblots(right).Value represents mean±SE fromﬁve independent experiments(treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP,0.01,or insulin,##P,0.01).(D)The effects of M2on the induction of HIF-1a by a variety of stimuli.HCT116cells were treated with30l M M2for 1h and were continuously incubated under the condition of hypoxia(1%oxygen)or in a medium containing100l M CoCl2or0.5mM H2O2for the indicated times.HIF-1a inhibition by pyrrolopyrazines663 at Shanghai Jiao Tong University on March 27, 2012 / Downloaded fromInduction of miR-199a-5p and miR-20a/bDespite the repression of HIF-1a protein,M2had no effect on the level of HIF-1a transcript,indicating that posttranscriptional mecha-nism might be involved in this process (Figure 3A).Since miRNAs play a role in the posttranscriptional regulation of HIF-1a ,we exam-ined the effect of M2on the expression of miRNAs that potentially interact with the 3#-untranslated region (UTR)of HIF-1A messenger RNA (mRNA).In an effort to identify miRNAs responsible for the inhibition of HIF-1a expression by M2,we searched the TargetScanDatabase and discovered that four sequence motifs of the 3#-UTR of HIF-1A match seed sequences of 10candidate miRNAs (i.e.miR-199a-5p,miR-20a/b,miR-93,miR-138,miR-18a/b,miR-106a/b and miR-519c).Among the candidate miRNAs,M2treatment signiﬁ-cantly elevated the miRNA levels of miR-199a-5p,miR-20a and miR-20b in HCT116cells (Figure 3B).This effect of M2was also observed in HT29cells.Consistently,transfection of HCT116cells with each miRNA mimics or a mixture of the mimics almost com-pletely abrogated HIF-1a induction (Figure 3C).The mixture was also active in HT29cells (data not shown).These results support the contention that M2inhibits HIF-1a induction and which may result from the upregulation of miR-199a-5p and miR-20a/b that pair to the complementary-binding sites within the 3#-UTR of HIF-1A mRNA.To determine how M2elevates the levels of miR-199a-5p and miR-20a,their precursor levels were assessed by real-time PCR assays (Figure 3D).Interestingly,M2treatment increased the levels of pre-miR-199a and pre-miR-20a,but not their primary precursors,suggest-ing that the miRNAs induction may be mediated by the maturation process of the primary miRNAs.Since miR-20a is transcribed within the miR-17-92cluster,other mature miRNAs expressed from the cluster (miR-17,miR-18a,miR-19a,miR-19b-1and miR-92a-1)were also monitored (Figure 3E).M2treatment had no effects on the levels of the miRNAs,being consistent with our contention that M2affects the maturation process of miR-199a and miR-20a but not their general transcription.In addition,M4,another pyrrolopyrazine metabolite,did not change miR-20a/b levels but decreased miR-199a-5p level (Figure 3F).Taken together,our results demonstrate that M2has the ability to facilitate the maturation of primary precursors to miR-199a-5p and miR-20a that block the translation of HIF-1A mRNA.Inhibition of HIF-1a de novo synthesis35S-Methioninepulse labeling experiments were performed to verifythe inhibitory effect of M2on the synthesis of HIF-1a protein.As expected,M2treatment abolished the de novo synthesis of HIF-1a in HCT116cells (Figure 4A).Since HIF-1a is continuously degraded by the 26S proteasome complex after multiple ubiquitination (3),treat-ment with MG132(a proteasome inhibitor)promoted HIF-1a accu-mulation in cells treated with insulin (Figure 4B,upper).This effect was almost entirely abolished by simultaneous M2treatment in HCT116or HT29cells.Moreover,M2diminished the accumulation of ubiquitinated HIF-1a by MG132(Figure 4B,lower).These results are in line with the notion that the inhibition of HIF-1a de novo synthesis by M2restrained the ubiquitination and proteosomal degra-tion of HIF-1a because of a decrease in its supply.In a continuing effort to ﬁnd the molecular mechanism of HIF-1a inhibition by M2,we next investigated whether M2alters the stability of HIF-1a .Cycloheximide,a general inhibitor of protein synthesis,was used to prevent HIF-1a de novo synthesis.HCT116cells treated with cycloheximide in combination with insulin displayed a gradual decrease in the level of HIF-1a as a function of time (Figure 4C).Simultaneous treatment of the cells with M2did not change the rate of HIF-1a degradation.These results demonstrate that HIF-1a repres-sion by M2may stem from the inhibition of HIF-1a de novo synthesis but not the change in the protein stability.Inhibition of cell proliferation and invasion/migrationHIF-1a activation promotes neovascularization,which features a key pro-cess in blood and nutrient supply (1–3).It is expected that HIF-1a sup-pression by M2inhibits cell proliferation.Having identiﬁed the ability of M2to suppress HIF-1a ,we examined its effect on cell proliferation and invasion/migration.M2signiﬁcantly decreased the rate of DNA synthe-sis,as indicated by the result of [3H]-thymidine incorporation assay (Figure 5A).Moreover,M2treatment attenuated serum-induced inva-sion/migration of HCT116cells (Figure 5B).Similarly,transfection with a mixture of miR-199a-5p and miR-20a mimics signiﬁcantly decreased the cell invasion and migration (Figure 5C).Our observations show that the inhibition of HIF-1a by M2may contribute to decreasing the pro-liferation and invasion/migration of the cancercell.Fig.2.M2inhibition of HIF-1a target gene induction.(A )Inhibition of HIF-1a nuclear accumulation by M2.The levels of nuclear HIF-1a weremeasured in the lysates of HCT116or HT29cells treated as described in Figure 1B.Immunoblottings for lamin A and HSP70conﬁrmed the purities of nuclear (NF)and cytoplasmic fractions (CF),respectively.(B )Real-time PCR assays of HIF-1a target gene transcripts.After serum deprivation (16h),HCT116cells were treated with 30l M M2for 1h and were continuously incubated with 100nM insulin for 12h.b -Actin was used as a normalizing reference.Value represents mean ±SE from ﬁve independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP ,0.01,or insulin,##P ,0.01).(C )Hypoxia-response element (HRE)reporter gene assay.HRE-A549cells that had been stably transfected with the HRE-luciferase construct were incubated with 100nM insulin for 24h following M2treatment for 1h.Luciferase activity was measured on the lysates.Value represents mean ±SE from ﬁve independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP ,0.01,or insulin,#P ,0.05;##P ,0.01).S.G.Kang et al.664at Shanghai Jiao Tong University on March 27, 2012/Downloaded fromHIF-1a repression by 7-ethyl-6,8-bis(methylthio)pyrrolo[1,2-a ]pyrazine Based on the novel pharmacologic effect of M2,pyrrolopyrazine analogs were synthesized with the aim of identifying other candidates that inhibit HIF-1a (Figure 6A).7-Ethyl-6,8-bis(methylthio)pyrro-lo[1,2-a ]pyrazine (N3b)had an inhibitory effect on HIF-1a induction,whereas 6,8-bis(methylthio)-7-phenylpyrrolo[1,2-a ]pyrazine (N3a)failed to do so (Figure 6B).Thus,7-ethyl derivative (N3b),but not 7-phenyl derivative (N3a),of pyrrolopyrazine was active in inhibiting HIF-1a .N3b treatment also induced the expression of miR-199a-5p and miR-20a,as did M2(Figure 6C).Overall,our results demonstrate that M2with pyrrolopyrazine structure and its 7-ethyl congenor have the ability to prevent the induction of HIF-1a ,and which may result from the inhibition of HIF-1a de novo synthesis,as mediated by the induction of miR-199a-5p and 20a.DiscussionHIF-1a is closely involved in angiogenesis and tumor growth (1–3).In previous studies,oltipraz inhibits the expression of vascular en-dothelial growth factor at the molecular level and has the ability to inhibit tumor growth and angiogenesis in tumor-bearing animal models (e.g.angiosarcoma and colon cancer)(13,14,30).Oltipraz treatment inhibits the activity of HIF-1a and its target gene trans-activation,thereby repressing angiogenesis and tumor growth (14).This effect appears to result from not only an increase in HIF-1a ubiquitination but also its accelerated degradation.In addition,olti-praz decreased the ability of insulin to produce H 2O 2,reactive oxy-gen species that inhibit prolyl hydroxylase domain protein-mediated hydroxylations of two proline residues of HIF-1a and consequent degradation of HIF-1a by the ubiquitin-proteasome system (14).Thus,the inhibition of HIF-1a by oltipraz results from destabiliza-tion of HIF-1a .Our results and others showed that the formation of M2occurs quickly after oltipraz administration in human or animals (19)and that M2exerts similar or possibly more potent beneﬁcial effects than its parent compound in several experimental models.Therefore,it was anticipated that M2inhibits the activity of HIF-1a in cancer cells.Here,we demonstrated for the ﬁrst time that M2and its 7-ethyl congener,but not M3and M4,have an inhibitory effect on the in-duction of HIF-1a .Moreover,our results demonstrated that M2treat-ment diminished cancer cell invasion and migration.In this study,we found no accumulation of ubiquitinated HIF-1a after M2treatment:Fig.3.The induction of mature miR-199a-5p and miR-20a/b by M2.(A )The effect of M2on HIF-1a mRNA level.HIF-1a mRNA levels were measured in HCT116cells treated as described in Figure 1B.Actinomycin D (an inhibitor of gene transcription)was used as a positive control.Value represents mean ±SE from ﬁve independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP ,0.01).(B )The effect of M2on the expression of miR-199a-5p and miR-20a/b.The levels of miRNAs were determined by real-time PCR assays in cells treated with 30l M M2for 3h after serum deprivation.Each miRNA level was normalized to that of U6snRNA.Value represents mean ±SE from three to ﬁve independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP ,0.01).(C )HIF-1a repression by the mimics of miR-199a-5p or miR-20a.HIF-1a was immunoblotted on the lysates of HCT116cells treated with the mimics of 100nM miR-199a-5p,miR-20a or combination of both (50nM each)for 3h.Equal loading of proteins was veriﬁed by immunoblottings for HIF-1b .(D )Real-time PCR assays.The levels of primary precursor or precursor miRNAs were measured as described in the legend to panel B.(E )The effect of M2on the levels of miRNAs in the miR-17-92cluster.(F )The effect of M4on miR-199a-5p and miR-20a/b levels.For the panels D,E and F,HCT116cells were treated with M2(or M4)as described above.Value represents mean ±SE from four to ﬁve independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃP ,0.05,ÃÃP ,0.01).N.S.,Not signiﬁcant.HIF-1a inhibition by pyrrolopyrazines665at Shanghai Jiao Tong University on March 27, 2012/Downloaded fromM2failed to change the half-life time of HIF-1a .Thus,the basis of HIF-1a inhibition by M2seems to differ from that of oltipraz (14).This is in line with our previous observation that M2,unlike oltipraz,failed to protect hepatocytes from oxidative stress elicited by arach-idonic acid and iron (21).So,it is probably that M2has a unique molecular basis for HIF-1a repression.Pyrrolopyrazine thione,an intermediate metabolite of oltipraz,causes the reduction of the heme iron via the interaction with cytochrome c (31–33).The membrane-bound cytochrome c then scavenges superoxide radicals and dimin-ishes excessive H 2O 2production (31–33).However,M2did not have this effect (21).Thus,the lack of accumulation in ubiquiti-nated HIF-1a by M2might result from decreased de novo synthesis.NF-j B heterodimer complex consisting of p50and p65transactivates the HIF-1A gene (34),which may be antagonized by certain chemicals (e.g.YC-1)(35).Unlike YC-1,M2had no effect on p50/p65expression or NF-j B reporter activity (data not shown),excluding the possibility that M2inhibits HIF-1a by repressing NF-j B activity.The lack of change in HIF-1A mRNA content by M2suggested that it inhibits HIF-1a at the posttranscriptional level.This hypothesis is strengthened by our observation showing a decreased translational rate of HIF-1a in cells treated with insulin that elevates HIF-1a level through a translational mechanism (26,27).Consistently,M2treatment signiﬁcantly restrained the synthesis rate of HIF-1a .Since 5#-terminal oligo pyrimidine sequences play a role in p70S6K1-dependent translation of HIF-1A mRNA (36),the inhibition of p70S6K1by olti-praz might contribute to inhibiting HIF-1a (14).Unlike oltipraz,M2failed to change p70S6K1phosphorylation (supplementary Figure S1is available at Carcinogenesis Online;the capital S denotes that the ﬁgure can be found in the supplemental material),implying that a dif-ferent mechanism exists for the translational regulation of HIF-1a by M2.The miRNAs are small non-coding RNAs that decrease the expres-sion of target proteins via the inhibition of mRNA translation with enzymatic and regulatory functions (37,38).The inhibitory action of miRNA results from imprecise base pairing of miRNAs withtheFig.4.Inhibition of HIF-1a de novo synthesis by M2.(A )[35S]-Methionine incorporation assay.HCT116cells that had been cultured in a medium free of methionine,cysteine and glutamine were pulse labeled with 100mCi/ml [35S]-methionine for 1h and were incubated in a medium containing methionine,cysteine and glutamine for 1.5h.[35S]-Methionine incorporation to HIF-1a was assessed in the lysates.Value represents mean ±SE from ﬁve independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP ,0.01,or 35S labeling alone,##P ,0.01).(B )The effect of M2on the ubiquitination and degradation of HIF-1a .HCT116or HT29cells transfected with the plasmid encoding for His-tagged ubiquitin (His-Ubi)were treated with MG132(10l M,3h)and were treated with insulin (100nM,3h)or insulin plus M2.Immunoblotting for ubiquitin was done on HIF-1a immunoprecipitates.HIF-1b wasimmunoblotted on the lysates.Value represents mean ±SE from ﬁve independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP ,0.01,or insulin alone,##P ,0.01).(C )The effect of M2on HIF-1a stability.HCT116cells were incubated with insulin or insulin þM2for the indicated times after cycloheximide (CHX,20l g/ml)treatment (upper).HIF-1a or HIF-1b was immunoblotted on the lysates (lower).Value represents mean ±SE from ﬁve independent experiments (treatment mean signiﬁcantly different from zero-time control,ÃÃP ,0.01,or insulin þCHX at respective time,##P ,0.01).S.G.Kang et al.666at Shanghai Jiao Tong University on March 27, 2012/Downloaded from3#-UTR of complementary mRNAs (37,38).It is known that a cluster of miR-17-92and miR-519c participate in hypoxia-induced HIF-1a accumulation (39,40).Under a normoxic condition,miR-17-92tran-scribed from the same cluster may target complementary HIF-1A mRNA for the regulation of its translation,playing an inhibitory role in cancer proliferation in an oxygen-independent manner (39).In rat hepatic sinusoidal endothelial cells,downregulation of miR-199by ethanol increased the levels of HIF-1A and endothelin receptor 1tran-scripts (41).Certain phytochemicals (i.e.curcumin,epigallocatechin-3-gallate and isoﬂavone)also affect the expression of miRNAs,leading to alterations in cellular signaling and biological behavior (42).However,the modulation of miRNAs responsible for HIF-1a translation by chemical means had never been explored.Here,we demonstrate for the ﬁrst time that M2and its 7-ethyl congenor induce the expression of miR-199a-5p and miR-20a responsible for the pre-vention of HIF-1a induction.Oltipraz and its major metabolite of M1,however,failed to increase the levels of miR-199a-5p andmiR-20aFig.5.Inhibition of cancer cell proliferation and invasion/migration by M2.(A )Inhibition of DNA synthesis by M2.HCT116cells were treated with 30l M M2for 24h and continuously exposed to 1l Ci/ml[methyl-3H]-thymidine for 8h.Cell proliferation was determined by measuring radioactivity.Value represents mean ±SE from ﬁveindependent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP ,0.01,or serum alone,##P ,0.01).(B )Repression of cell invasion/migration by M2.Invaded/migratedHCT116cells were counted under light microscope (magniﬁcation,Â200).Value represents mean ±SE from four independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃP ,0.05,ÃÃP ,0.01,or serum alone,#P ,0.05).(C )The effect of a mixture of miR-199a-5p and miR-20a mimics on cell invasion/migration.HCT116cells were treated with miR-199a-5p and miR-20a mixture (50nM each).Value represents mean ±SE from four independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃÃP ,0.01,or serum alone,#P ,0.05,ÃP ,0.01).Fig.6.The effects of synthetic analogs of M2on the induction of HIF-1a .(A )The chemical structures of pyrrolopyrazine derivatives (N3a and N3b).(B )HIF-1a repression by N3b.HCT116cells were treated with each pyrrolopyrazine derivative (30l M each)for 1h and were continuously incubated in a medium containing 100nM insulin for 6h.Value represents mean ±SE from ﬁve independent experiments [treatment mean signiﬁcantly different from insulin treatment alone (100%),ÃÃP ,0.01].(C )The effect of N3b treatment on miR-199a-5p and miR-20a expression.miR-199a-5p and miR-20a levels were measured by real-time PCR assays in HCT116cells treated with 30l M N3b for 3h after serum deprivation.Each miRNA level was normalized to that of U6snRNA.Value represents mean ±SE from ﬁve independent experiments (treatment mean signiﬁcantly different from vehicle-treated control,ÃP ,0.05,ÃÃP ,0.01).HIF-1a inhibition by pyrrolopyrazines667at Shanghai Jiao Tong University on March 27, 2012/Downloaded from。

闯入动物王国的植物miRNA丨BioArt推荐

闯入动物王国的植物miRNA丨BioArt推荐导读：蔬菜水果富含人体所必需的营养物质，包括糖、维生素、无机盐、及植物纤维。

除了这些耳熟能详的营养物质外，近几年研究发现，蔬菜水果里的小分子RNA—microRNA（miRNA），也可以被人体吸收。

这些植物miRNA经口服进入消化道后，不仅能稳定生存下来，还能被机体吸收进入血循环，从而在不同靶器官发挥作用。

本文将围绕“植物miRNA的吸收”以及“植物miRNA如何在动物体内发挥作用”两个问题来介绍这些闯入动物王国的植物miRNA。

（引自2015，Lu Han et al., Frontiers in Plant Science）撰文丨汪劼博士（Cell Reseearch编辑部）miRNA是一类不编码蛋白质的单链小分子RNA，长度为20~24个核苷酸，能够通过序列配对，结合到靶基因mRNA上，特别是mRNA的3’端非翻译区(3’-untranslational region, 3’-UTR)。

如果序列完全匹配，会造成目标mRNA被切割，断裂的mRNA之后会被降解。

如果miRNA和目标mRNA不完全互补结合，这将抑制mRNA翻译成蛋白质，而不影响mRNA的稳定性。

以上也是哺乳动物miRNA作用的两种主要方式。

miRNA本身不具备酶活性，所以它要发挥作用，需要把一个具有酶活力的蛋白质复合物——RNA诱导沉默复合物(RNA induced silencing complex, RISC) 引到目标mRNA上。

RISC的核心分子是argonaute (Ago)，对于目标mRNA的切割或者翻译抑制，都是必不可少的(图 1)。

图1 比较动植物miRNA的合成和作用方式。

(A) 植物miRNA 的合成和作用方式。

RNA聚合酶II (RNA polymerase II, Pol Ⅱ)催化生成pri-miRNA，随后核内的核糖核酸酶DCL1实施两次切割，先后生成具有茎环结构pre-miRNA以及miRNA/miRNA* duplex，随后miRNA/miRNA*的3′末端会被HEN1酶加上甲基化。

来曲唑诱导大鼠多囊卵巢综合症模型的构建及相关microRNAs的筛选验证

华中科技大学硕士学位论文来曲唑诱导大鼠多囊卵巢综合症模型的构建及相关microRNAs的筛选验证姓名：***申请学位级别：硕士专业：妇产科学指导教师：***2011-05来曲唑诱导大鼠多囊卵巢综合症模型的构建及相关microRNAs的筛选验证华中科技大学同济医学院附属同济医院妇产科研究生班自芹导师钟刚教授摘要第一部分来曲唑诱导大鼠PCOS动物模型的构建及基因芯片的制备筛选目的： 1. 采用来曲唑灌胃方法构建雌性Wistar大鼠PCOS动物模型，并分析比较模型组与对照组的血清睾酮（T），雌二醇（E2）和黄体生成素（LH）水平变化，胰岛素抵抗相关的特征及卵巢的形态学改变。

2. 利用基因芯片的技术筛选两组之间差异表达的microRNAs，探讨其参与PCOS发生和发展过程中的可能机制。

方法：1、选取6周龄清洁级的雌性Wistar大鼠，随机分组为模型组和对照组，每组各20只。

PCOS模型组: 每日来曲唑1 mg/( kg·d)溶于1%的羧甲基纤维素(CMC)中,连续灌服21 d；对照组：不予处理，正常喂养。

从用药的第10天开始每日进行阴道涂片至用药期结束，在最后一次应用来曲唑24h(并禁食12h)后，同时在处理对照组大鼠时，尽量控制其在动情间期。

水合氯醛麻醉后切取卵巢，心脏取血，分离血清。

全自动化学发光检测仪测定血清T，E2和LH；放射免疫学方法测定空腹血清胰岛素（FINS）, 血糖仪测定空腹血糖（FBG），并计算胰岛素抵抗指数（HOMA1-IR）；称重卵巢并测定大鼠体重；卵巢组织切片，HE染色，并观察其病理变化。

2．从造模成功的PCOS模型组及正常对照组中各随机选取3只大鼠，10%的水合氯醛腹腔麻醉后，心脏取血后迅速取出双侧卵巢，称重后将其中的一个卵巢液氮冷冻固定保存，送往北京博奥生物有限公司应用最新版本15.0的LC-science microRNAs表达谱微阵列芯片进行筛选microRNAs。

MicroRNA(miRNA)

MicroRNAs (miRNAs) are endogenous single-
stranded RNAs of 18-25nt in eukaryotic organisms,
which can regulate the complementary mRNAs at
the post-transcriptional level through cleavage or translational repression of the mRNA targets．
近几年来,在动物细胞和植物组织中,上百种 miRNA被陆续发现。
Recent years，several hundred miRNAs from animals and plants have been identified．
Recent years, more than hundred miRNAs have been identified from animals and plants in succession.
这些小分子调控RNA是从60~200 nt的具有发夹状结构的前体中被切割出来而成熟的
These small modulatory RNAs are cleavaged from a precursor of 60~200nt RNA hairpin．
These small modulatory RNAs are cleavaged from precursors of 60~200nt RNA hairpin
Key words miRNA maturation，miRNA，pri-miRNA，pre-miRNA
摘要评述(abstract review)
通篇来看，摘要部分涵盖了文章基本内容的所有要点，并依靠其内在的逻辑关系有机地组织在一起

microRNA在甲壳动物中的研究进展

microRNA在甲壳动物中的研究进展摘要：目前为止，众多的microRNAs已经从各种组织中被发现并提取，包括哺乳动物，植物，昆虫，线虫动物，和病毒等。

microRNAs是一类在真核生物中广泛存在的大小在22~24nt 左右，单链，内源性，非编码，进化上高度保守的小分子RNA，在转录水平上，通过和靶mRNAs互补结合调控基因表达，在RNA信号通路上，干扰RNA通路正常运行。

研究发现microRNAs在生物体具有高度的保守性、时序性、组织特异性的转录后调控因子，在调控途径：生长、发育、生殖、细胞分化、造血作用、细胞增殖与凋亡、疾病、代谢、信号转导、胁迫应答以及免疫（调节先天免疫和适应性免疫）等方面发挥重要调控作用。

有关microRNAs 的研究已经取得了众多的科研成果，但在一些甲壳动物中研究还比较缺乏，比如：斑节对虾。

在甲壳动物中，最先得到深入研究的是水溞，2011年，在水溞中发现了45种miRNAs，同年，在日本囊对虾中也首次发现了35 种miRNAs，其中的11种miRNAs，和其他已知节肢动物相比，显示了高同源性。

据2015年数据显示，在甲壳类动物，已经有数十种microRNAs 被鉴定，包括螯虾( Procambarus clarkii)，日本囊对虾( Marsupenaeus japonicus ) ，中华绒螯蟹(Eriocheirsinensis)等。

本文主要对microRNAs的基本概念，形成，作用机理，在甲壳动物中的生物学功能，研究应用，发展前景等方面作有限的总结，以期能为甲壳动物microRNAs的研究发展起到推动作用。

关键词：microRNAs；甲壳动物；调控；免疫；对虾Abstract：Till date numerous microRNAs (miRNAs) have been discovered from variousorganisms, including mammals, plants, insects, nematodes and viruses. MicroRNAs are a kind of around 22 ~ 24 nt, single strand, endogenous, non-coding, evolutionary highly conservative RNAs which widely exist in eukaryotic. miRNAs regulate gene expression at the post-transcriptional level and play an important role in development, reproduction, cell differentiation, hematopoiesis, cell proliferation and apoptosis, disease, metabolism, signal transduction, stress response and immunological defense function, as shown in Figure 1. Studies of microRNAs has made many achievements, but in some crustaceans the research is relatively lack, such as: Penaeus monodon. In crustaceans, Daphnia is the first to get in-depth study. In 2011, 45 kinds of miRNAs were found in Daphnia. The same year, 35 species of miRNAs were also found for the first time in Marsupenaeus japonicas. Among them, one of the 11 kinds of miRNAs, comparing with those of other known arthropod, showed high homology. According to the data in 2015, in crustaceans, dozens of microRNAs have been identified, including Procambarus clarkia, Marsupenaeus japonicas, Eriocheirsinensis, etc. This article mainly discusses the basic conception, the formation and action mechanism of microRNAs, biological function in crustaceans, research and application, the development prospect in order to promote the research and development for crustaceans’ microRNAs.Keywords: microRNAs; crustaceans; Regulation; Immune; prawn;前言随着虾、蟹等水产十足目甲壳动物养殖业在世界范围内迅速发展，人们对其需求的逐渐升高，必然会大量养殖，但经常高密度养殖和过剩投饵等原因，导致养殖池的饲养环境急剧恶化，由细菌和病毒引起的传染性疾病也逐渐增多，传统上治疗和预防此类疾病主要依赖抗生素、化学药物等，这些药物的滥用造成环境污染、药物残留、产生耐药性细菌等严重问题也就成为困扰甲壳动物养殖的一个重要环节[1]，运用动物自身介导的免疫功能来解决这一问题，不仅于环境，还是动物生长本身，都是相对好的途径，甲壳动物是依靠血细胞吞噬和包囊化作用发挥其免疫防御机能，这就体现了动物机体中的miRNA，microRNAs在生物体具有高度的保守性、时序性、组织特异性的转录后调控因子[2]，在调控途径：生长、发育[3-4]、生殖、细胞分化[5]、造血作用、细胞增殖[6]与凋亡、疾病、代谢[7]、信号转导、胁迫应答以及免疫[8]（调节先天免疫和适应性免疫）等方面发挥重要调控作用(图1)，它只需通过几个碱基互补便可发挥作用，因此在免疫反应中，miRNA快速、精细而又柔和的调控就显得至关重要。

高通量测序鉴定中间锦鸡儿干旱条件下的microRNA

中国农业科技导报，2021,23(3)：51-57Journal of Agricultural Science and Technology高通量测序鉴定中间锦鸡儿干旱条件下的microRNA 苏雨萌§,张旭婷§,特日格乐，田敏，尚晓蕊，李国婧，王瑞刚**(内蒙古农业大学生命科学学院，植物逆境生理与分子生物学自治区重点实验室，呼和浩特010018)摘要：中间锦鸡儿分布于干旱和半干旱地区，适应干旱和高温逆境环境，被广泛应用于固沙和水土保持，具有很高的生态价值。

microRNA是一类非编码RNA,广泛分布于植物体内，参与干旱、盐、低温等多种胁迫响应。

为了鉴定中间锦鸡儿中抗旱相关的miRNA,构建了干旱条件的small RNA文库，通过高通量测序和生物信息学分析，共鉴定得到116个miRNA,88个保守的miRNA属于33个已知miRNA家族和28个新miRNA，差异表达的miRNA中，cin-miR164a、cin-miR164b、cin-miR168a、cin-miR168b在三个干旱处理时间下调表达，cin-novel-3、cin-novel-11、cin-novel-21在干旱处理1和3h上调表达，cin-novel-26在干旱处理3h特异表达;28个新miRNA通过psRNATarget在中间锦鸡儿中预测到582个靶基因，在拟南芥中预测到212个靶基因，大多数靶基因参与干旱胁迫响应。

这些为后续研究中间锦鸡儿miRNA响应干旱胁迫奠定了基础。

关键词：中间锦鸡儿;干旱胁迫;microRNA;高通量测序;靶基因预测doi:10.13304/j.nykjdb.2019.0805中图分类号:Q78文献标识码:A文章编号：1008-0864(2021)03-0051-07Identification of microRNAs in Caragana intermedia Kuang by High Throughput Sequencing Under Drought StressSU Yumeng§，ZHANG Xuting§，Terigele，TIAN Min,SHANG Xiaorui，LI Guojing,WANG Ruigang*(Inner Mongolia Key Laboratory of Plant Stress Physiology and Molecular Biology,College of Life Sciences,InnerMongolia Agricultural University,Hohhot010018,China)Abstract:Caragana intermedia Kuang distributes in the arid and semi-arid area,and it could tolerate drought and extreme temperature,so it is used widely in sand fixation,soil and water preservation with high ecology value.microRNAs are one class of noncoding RNA and ubiquitous in plants,and they involves in response to a wide variety of stresses including drought,salinity,chilling temperature etc.In order to identify the drought-responsive miRNA inC.intermedia,this study constructed small RNA library of C.intermedia under drought stress,screened the drought-responsive miRNAs using high throughput sequencing and bioinformatics analysis.A total of116miRNAs were screened,among which88conservative miRNAs belonged to33known families and28novel miRNA were identified.Among the differential expression miRNAs,cin-miR164a,cin-miR164b,cin-miR168a,cin-miR168b in three drought stress treatments were down-regulated compared with the control,and cin-novel-3,cin-novel-11,cin-novel-21at1and3h after drought stress were up-regulated compared with the control;cin-novel-26had a specific expression at3h;28novel miRNA of C.intermedia were predicted582target genes in C.intermedia and212target genes in Arabidopsis thaliana by psRNATarget database.Most of the target genes responsed to drought stress.These results provided further understanding of miRNA regulation in response to drought stress in C.intermedia.Key words:Caragana intermedia Kuang;drought stress;microRNA;high throughput sequencing;target gene prediction收稿日期：2019-09-29;接受日期：2019-12-18基金项目：国家自然科学基金项目(31760696);内蒙古自治区科技创新引导奖励资金项目(KCBJ2018012).联系方式：§苏雨萌与张旭婷为本文共同第一作者。

植物对人类环境动物的重要性英语作文

植物对人类环境动物的重要性英语作文全文共3篇示例，供读者参考篇1The Importance of Plants to Human, Environment and AnimalsPlants hold a significant importance to human, environment and animals for a variety of reasons. From providing food and oxygen to regulating the climate and preserving biodiversity, the role of plants in our everyday lives is truly indispensable. In this essay, we will explore the various ways in which plants impact our world.First and foremost, plants provide us with food. They are the primary producers in the food chain, converting sunlight into energy through the process of photosynthesis. This energy is then passed on to herbivores, which in turn are consumed by carnivores. Without plants, the entire food chain would collapse, leading to a global food crisis.In addition to providing us with food, plants also play a crucial role in producing oxygen. Through photosynthesis, plants release oxygen as a byproduct, which is essential for the survivalof all living organisms. Without plants, the levels of oxygen in the atmosphere would decrease significantly, endangering the health of humans, animals, and the environment.Furthermore, plants help regulate the climate by absorbing carbon dioxide from the atmosphere. Carbon dioxide is a greenhouse gas that contributes to global warming and climate change. By removing carbon dioxide from the air, plants help to mitigate the effects of climate change and create a more stable climate for all living beings.Plants are also important in preserving biodiversity. They provide habitats for a wide variety of organisms, from insects to birds to mammals. By creating diverse ecosystems, plants support the health and vitality of the natural world, ensuring the survival of countless species.Moreover, plants have medicinal properties that have been utilized by humans for thousands of years. Many of our modern medicines are derived from plant compounds, which have been shown to have therapeutic effects on a wide range of diseases and ailments. Without plants, our ability to heal and treat illness would be severely limited.In conclusion, the importance of plants to human, environment and animals cannot be overstated. From providingfood and oxygen to regulating the climate and preserving biodiversity, plants are essential to the health and well-being of our planet. It is crucial that we recognize and appreciate the value of plants, and work to protect and preserve them for future generations. Only by doing so can we ensure a sustainable and thriving world for all living beings.篇2The Importance of Plants to Human, Environment, and AnimalsPlants play a crucial role in sustaining life on Earth. They provide food, oxygen, shelter, and many other essential resources for humans, animals, and the environment. In this essay, we will explore the various ways in which plants are important to our planet and its inhabitants.First and foremost, plants are vital to human survival. They are a primary source of food for the majority of the world's population. Fruits, vegetables, grains, and legumes are all derived from plants and form the basis of a healthy diet. Furthermore, plants are used to produce a wide range of other products, including clothing, shelter, medicine, and fuel. Without plants, human civilization as we know it would not exist.Plants also play a key role in maintaining a healthy environment. They absorb carbon dioxide from the atmosphere and release oxygen through the process of photosynthesis. This oxygen is essential for the respiration of both humans and animals. Additionally, plants help to regulate the climate by absorbing excess carbon dioxide and reducing the greenhouse effect. They also help to prevent soil erosion, filter pollutants from the air and water, and provide habitats for a diverse array of species.In addition to their importance to humans and the environment, plants also play a critical role in supporting the animal kingdom. Many animals rely on plants for food, either directly by eating plant material or indirectly by consuming herbivores. Plants provide sustenance for herbivores, which in turn serve as prey for carnivores. The complex web ofplant-animal interactions is essential for maintaining biodiversity and ecosystem balance.In conclusion, plants are an integral part of the interconnected web of life on Earth. They provide essential resources for humans, animals, and the environment, and play a key role in maintaining the balance of our planet's ecosystems. It is crucial that we recognize and appreciate the importance ofplants and work to protect and preserve them for future generations. By supporting plant conservation efforts and sustainable agriculture practices, we can ensure a healthy planet for all of its inhabitants.篇3The Importance of Plants to the Environment, Humans, and AnimalsPlants play a crucial role in the ecosystem by providing oxygen, food, shelter, and habitat for both humans and animals. They are essential for maintaining the balance of our planet's ecosystems and are a vital component of the environment.First and foremost, plants are responsible for producing oxygen through the process of photosynthesis. This oxygen is essential for the survival of all living organisms, including humans and animals. Without plants, the atmosphere would lack oxygen, making it impossible for humans and animals to breathe. In addition to producing oxygen, plants also act as carbon sinks, absorbing carbon dioxide from the atmosphere and helping to mitigate climate change.Plants are also a valuable source of food for humans and animals. Fruits, vegetables, grains, and nuts are all derived fromplants and are essential components of a healthy diet. In addition to providing nutrition, plants also contain medicinal properties that can be used to treat various ailments and diseases. Many pharmaceutical drugs are derived from plant compounds, making plants an important resource for human health.Furthermore, plants provide habitat and shelter for a wide variety of animal species. Forests, grasslands, and wetlands are home to countless animals, including insects, birds, mammals, and reptiles. These habitats are created and maintained by plants, which provide food, nesting sites, and protection for these animals. Without plants, many animal species would be unable to survive, leading to a loss of biodiversity and ecosystem function.In addition to their direct benefits to humans and animals, plants also play a key role in maintaining the health of the environment. Plants help to prevent soil erosion, regulate the water cycle, and purify the air and water. They also provide valuable ecosystem services, such as pollination and seed dispersal, which are essential for the reproduction and survival of plant species.In conclusion, plants are indispensable to the environment, humans, and animals. Their importance cannot be overstated, as they provide essential services that are vital for the health and well-being of all living organisms on Earth. It is crucial that we protect and preserve plant biodiversity to ensure the continued survival of our planet and its inhabitants. Only by recognizing the value of plants can we hope to sustainably manage our natural resources and ensure a healthy and prosperous future for all.。

微生物与我们作文500字

微生物与我们作文500字英文回答：Microorganisms, also known as microbes, are tiny living organisms that are invisible to the naked eye. They include bacteria, viruses, fungi, and protozoa. These microorganisms play a significant role in our lives, both positive and negative.On the positive side, microorganisms are essential for maintaining the balance of our ecosystem. They help in the decomposition of organic matter, which is crucial for recycling nutrients in the environment. For example, bacteria break down dead plants and animals, releasing nutrients back into the soil. This process is vital for the growth of new plants.Microbes also play a crucial role in the production of food and beverages. For instance, yeast, a type of fungi,is used in the fermentation process to make bread, beer,and wine. Bacteria are used to produce yogurt and cheese. Without these microorganisms, many of our favorite foods and drinks would not exist.Furthermore, microorganisms are used in various industries for the production of enzymes, antibiotics, and other useful substances. For example, bacteria are used to produce insulin, a hormone used in the treatment of diabetes. Enzymes produced by microorganisms are used in laundry detergents to remove stains effectively.However, microorganisms can also have negative effects on our health. Some bacteria and viruses can cause diseases in humans and animals. For example, the flu virus and the bacteria that cause tuberculosis are responsible for many illnesses and deaths worldwide. These microorganisms can spread through the air, contaminated food, or direct contact with an infected person.To prevent the spread of diseases, it is important to practice good hygiene, such as washing hands regularly and covering the mouth and nose when coughing or sneezing.Vaccinations are also crucial in protecting ourselves from harmful microorganisms.中文回答：微生物，也被称为微生物，是肉眼无法看见的微小生物。

谈谈微生物与人类的关系英语作文高中

谈谈微生物与人类的关系英语作文高中全文共3篇示例，供读者参考篇1Microorganisms, also known as microbes, are tiny living organisms that are all around us. They exist in the air, soil, water, and even inside our bodies. The relationship between microorganisms and humans is complex and multifaceted, with both positive and negative aspects.On the positive side, microorganisms play crucial roles in many aspects of our lives. For example, they are essential for the decomposition of organic matter, which helps to recycle nutrients in the environment. Without microbes, dead plants and animals would accumulate, leading to a buildup of toxic gases and other harmful substances. Microorganisms are also important for agriculture, as they help to break down soil nutrients and make them available to plants. In addition, many microbes are used in the production of food and beverages, such as cheese, yogurt, and beer.Furthermore, some microorganisms are beneficial for human health. The human body is home to trillions of bacteria, viruses,and fungi, collectively known as the human microbiome. These microbes play a vital role in digestion, immune function, and overall well-being. For example, certain bacteria in the gut help to break down food and absorb nutrients, while others help to protect against harmful pathogens. Additionally, some microbes produce vitamins and other essential compounds that the body needs to function properly.However, not all microorganisms are beneficial. Some can cause diseases and infections in humans. Pathogenic bacteria, viruses, and fungi can enter the body through various means, such as contaminated food or water, insect bites, or direct contact with an infected person. Once inside the body, these microbes can multiply rapidly and cause symptoms ranging from mild to severe. Common examples of microbial infections include the flu, pneumonia, and food poisoning.Fortunately, advancements in science and medicine have led to the development of vaccines, antibiotics, and other treatments to combat microbial infections. Vaccines work by stimulating the immune system to produce antibodies that can fight off specific pathogens. Antibiotics, on the other hand, work by targeting the bacteria causing the infection and killing them. However, the overuse and misuse of antibiotics have led to theemergence of antibiotic-resistant bacteria, posing a significant threat to public health.In conclusion, the relationship between microorganisms and humans is one of mutual dependence and interaction. While some microbes are essential for our survival and well-being, others can pose a threat to our health. It is crucial to understand and appreciate the role of microorganisms in our lives, and to take steps to promote a balanced and harmonious relationship with these tiny but mighty creatures. Through continued research and education, we can harness the power of microbes for the greater good and ensure a healthier future for all.篇2The Relationship between Microorganisms and HumansIntroduction:Microorganisms are tiny living organisms that are not visible to the naked eye. They exist in almost every environment on Earth, from the depths of the ocean to the heights of the atmosphere. While some microorganisms can cause diseases, the majority of them are actually beneficial to humans and play a crucial role in our daily lives. In this essay, we will explore therelationship between microorganisms and humans, focusing on how they impact our health, agriculture, and environment.Health:Microorganisms play a vital role in maintaining our health. The human body is home to trillions of bacteria, viruses, and fungi, collectively known as the human microbiota. These microorganisms help us digest food, produce essential vitamins, and protect us from harmful pathogens. For example, the bacteria in our gut help break down food and absorb nutrients, while the bacteria on our skin prevent harmful pathogens from entering our bodies. In addition, certain microorganisms, such as probiotics, can improve our immune system and reduce the risk of infections.However, some microorganisms can also cause diseases. Pathogenic bacteria, viruses, and fungi can infect our bodies and lead to illnesses such as pneumonia, influenza, and food poisoning. Fortunately, modern medicine has developed antibiotics, antiviral drugs, and vaccines to combat these harmful microorganisms. It is essential to maintain a balance between beneficial and harmful microorganisms to protect our health.Agriculture:In agriculture, microorganisms are essential for soil fertility and plant growth. Soil bacteria and fungi decompose organic matter, releasing nutrients such as nitrogen, phosphorus, and potassium that are essential for plant growth. Some microorganisms also form symbiotic relationships with plants, helping them absorb water and nutrients from the soil. In addition, certain bacteria and fungi can protect plants from diseases by producing antibiotics or competing with harmful pathogens.Microorganisms are also used in biotechnology to improve crop yields and reduce environmental impact. For example, genetically modified crops that are resistant to pests or herbicides are developed using microorganisms. In addition, bioremediation techniques use microorganisms to clean up polluted soil and water by breaking down toxic chemicals. By harnessing the power of microorganisms, farmers can produce more food with less environmental harm.Environment:Microorganisms play a crucial role in recycling nutrients and organic matter in the environment. Bacteria and fungi decompose dead plants and animals, releasing nutrients back into the soil. These nutrients are then taken up by plants,completing the nutrient cycle. In addition, microorganisms help regulate the Earth's climate by cycling carbon and nitrogen between the atmosphere, soil, and oceans.However, human activities, such as deforestation, pollution, and climate change, can disrupt the balance of microorganisms in the environment. For example, the excessive use of fertilizers and pesticides can kill beneficial microorganisms in the soil, leading to soil degradation and loss of biodiversity. It is essential to protect and restore the natural habitats of microorganisms to maintain a healthy environment for future generations.Conclusion:In conclusion, the relationship between microorganisms and humans is complex and multifaceted. While some microorganisms can cause diseases, the majority of them are beneficial and essential for our health, agriculture, and environment. By understanding and harnessing the power of microorganisms, we can improve our lives and protect the planet for future generations. It is crucial to strike a balance between beneficial and harmful microorganisms to ensure a sustainable and healthy future for all living organisms on Earth.篇3Microorganisms and Their Relationship with HumansIntroductionMicroorganisms, also known as microbes, are tiny organisms that can only be seen under a microscope. They include bacteria, viruses, fungi, and other single-celled organisms. While some microbes can cause diseases, many are essential for life on Earth. In fact, humans have a very close relationship with microorganisms, as they play crucial roles in various aspects of our lives.HealthMicroorganisms can have both positive and negative impacts on human health. On one hand, harmful bacteria and viruses can cause infectious diseases such as influenza, tuberculosis, and COVID-19. On the other hand, beneficial microbes are important for maintaining a healthy immune system and gut microbiota. For example, probiotics are live bacteria and yeasts that are good for our digestive system. They can help prevent and treat conditions such as diarrhea and irritable bowel syndrome.FoodMicroorganisms are also important in the food industry. Yeasts and bacteria are used to ferment food and beverages such as bread, yogurt, cheese, and beer. Fermentation not only helps preserve food, but also enhances its flavor and nutritional value. For example, the bacteria in yogurt can help improve digestion and boost the immune system. Without microorganisms, many of our favorite foods and drinks would not exist.EnvironmentMicroorganisms play a vital role in the environment by breaking down organic matter and recycling nutrients. They decompose dead plants and animals, turning them into nutrients that can be used by other organisms. This process, known as decomposition, is essential for the health of ecosystems. Additionally, certain microbes can help clean up pollutants and contaminants in soil and water. For example, some bacteria can break down oil spills and heavy metals, helping to restore damaged ecosystems.MedicineMicroorganisms have revolutionized the field of medicine. They have been used to produce antibiotics, vaccines, and other lifesaving drugs. Penicillin, for example, was the first antibioticdiscovered and has saved countless lives since its introduction. Vaccines work by stimulating the immune system to create antibodies against specific pathogens, preventing infection and disease. In recent years, scientists have also been exploring the potential of using microbes to treat diseases such as cancer and diabetes.ConclusionIn conclusion, microorganisms have a significant impact on human health, food production, the environment, and medicine. While some microbes can be harmful, many are essential for our survival and well-being. As our understanding of microorganisms grows, so does our ability to harness their potential for the benefit of humanity. It is important to continue studying and exploring the vast world of microbes, to better understand and appreciate their role in our lives.。

微生物英语作文

微生物英语作文In the vast expanse of the natural world, there exists a realm so small that it is invisible to the naked eye yet so significant that it underpins the very fabric of life on Earth. This is the world of microorganisms, a diverse and complex kingdom that includes bacteria, viruses, fungi, and protozoa. Their roles are multifaceted, ranging fromessential to detrimental, and understanding them is crucial for various fields, from medicine to environmental science.Microorganisms are the oldest and most abundant life forms on our planet. They have been around for billions of years, adapting and evolving to fill every conceivable ecological niche. Some microorganisms are autotrophs, capable of producing their own food through photosynthesis or chemosynthesis, forming the base of many food chains. Others are heterotrophs, relying on organic matter produced by other organisms for sustenance.One of the most significant contributions of microorganisms to our world is their role in the nitrogen cycle. Certain bacteria, such as Rhizobium, fix atmospheric nitrogen, converting it into a form that plants can use. This processis vital for plant growth and, by extension, for the survival of all animals that depend on plants for food.However, not all microorganisms are beneficial. Some are pathogens, causing diseases in plants, animals, and humans.The common cold, influenza, and even the recent COVID-19 pandemic are all caused by viruses. Bacterial infections,such as strep throat and tuberculosis, are also widespread. The study of these harmful microorganisms is essential for developing treatments and vaccines to protect public health.Microorganisms also play a key role in the decomposition process, breaking down dead organic matter and recycling nutrients back into the ecosystem. Without them, waste would accumulate, and the cycle of life would be severely disrupted.In the field of biotechnology, microorganisms are harnessedfor a variety of applications. They are used in theproduction of antibiotics, enzymes, and other pharmaceuticals. In the food industry, microorganisms are essential for the fermentation process, which is used to make products like yogurt, bread, and beer.Despite their importance, microorganisms are often overlooked due to their small size. However, with the advent of advanced microscopy and molecular biology techniques, ourunderstanding of these tiny life forms has expanded dramatically. The more we learn, the more we realize how interconnected we are with the microbial world.In conclusion, microorganisms are a fundamental part of our planet's ecosystem, with roles that are both beneficial and harmful. They are a testament to the diversity of life andthe intricate balance that exists in nature. As we continueto explore the world of microorganisms, we uncover not onlythe secrets of life at its smallest scale but also gaininsights that can help us address some of the world's most pressing challenges.。

描写植物的科普文作文

描写植物的科普文作文英文回答：Plants: The Foundation of Life.Plants are the primary producers in the food chain, providing food and oxygen for all other living organisms on Earth. They play a crucial role in maintaining the balance of the ecosystem and are essential for the survival of life on our planet.Structure and Physiology of Plants.Plants have a complex structure that enables them to perform photosynthesis, the process by which they convert sunlight, water, and carbon dioxide into glucose, a sugar that provides them with energy. The main components of a plant are:Roots: Anchor the plant in the soil and absorb waterand nutrients.Stem: Supports the plant and transports water and nutrients from the roots to the leaves.Leaves: Contain chlorophyll, the green pigment that absorbs sunlight for photosynthesis.Flowers: Reproductive structures that produce seeds.Fruits: Matured ovaries that protect and disperse seeds.Types of Plants.There are over 300,000 species of plants on Earth, classified into two main groups:Vascular Plants: Have specialized tissues called xylem and phloem for transporting water and nutrients. Examples include ferns, gymnosperms, and flowering plants.Non-vascular Plants: Lack specialized tissues for transport and rely on diffusion for nutrient and water exchange. Examples include mosses, liverworts, and algae.Importance of Plants.Plants provide numerous benefits to humans and the environment:Food: The main source of food for humans and animals.Oxygen: Released through photosynthesis, which is essential for life.Medicine: Many plants contain compounds used in pharmaceuticals.Shelter: Provide building materials and protection from the elements.Erosion Control: Roots hold soil in place, preventing erosion.Carbon Sequestration: Absorb carbon dioxide from the atmosphere, helping to reduce greenhouse gas emissions.Conservation of Plants.The conservation of plants is vital for the well-being of our planet. Deforestation, pollution, and climate change pose significant threats to plant diversity. Conservation efforts include:Protected Areas: Establishing parks and reserves to protect plant habitats.Sustainable Forestry: Managing forests responsibly to ensure their long-term health.Native Plant Restoration: Reintroducing native plants to their original ecosystems.Education and Awareness: Raising awareness about the importance of plants and how to protect them.中文回答：植物，生命的基石。

MicroRNA在非洲猪瘟研究中的应用

动物医学进展,02 ,42(4)=120-123Progress in Veterinary MedicineMicroRNA 在非洲猪瘟研究中的应用张兆博1，张思诗2,汉可欣1，李晓易3,文雪霞1，汉丽梅1宀(.沈阳农业大学畜牧兽医学院，辽宁沈阳1 10866； 2.中国农业科学院上海兽医研究所，上海20024 1 ； 3.长春师范大学，吉林长春130031; 4.东北畜禽疫病研究教育部重点实验室，辽宁沈阳1 10866)摘要:microRNA 是非编码RNA 中一种重要的不具有编码能力的调节RNA ,它广泛存在于真核生物体内并对机体的发育、细胞凋亡、基因表达及蛋白质表达等一系列生物学过程起调控作用。

非洲猪瘟(Af-rican swine fever , ASF)是一种传染性强、危害大的急性传染病,已严重危害我国养猪业的正常发展。

对 ASF 发病过程中microRNA 的研究已成为近年来ASF 的研究热点之一。

论文对近年来ASF 发病过程中的microRNA 的作用及其机制进行综述，为未来microRNA 在ASF 防控中发挥作用提供参考。

关键词：非洲猪瘟；microRNA ；非洲猪瘟病毒中图分类号:S852.651非洲猪瘟(African swine fever, ASF )是由非洲猪瘟病毒(African swine fever virus , ASFV )感染引起的急性、热性传染病，家猪和野猪都为该病的易感对象。

ASFV 是一种20面体、有囊膜的双链DNA病毒，不同来源的分离株病毒基因组长度在170 kb~193 kb 之间［1］。

ASFV 约有151个〜167个开放阅读框(open reading frame, ORF )编码5个多基因家族，但目前部分ORF 编码蛋白的功能尚未明确⑵。

ASFV 的传播方式多样，其既可以通过易感动物之间的直接接触传播，也可以通过污染的猪肉、毒蛇、车辆、人及扁虱等途径间接传播［］。

普通野生稻miR160f的克隆和功能分析

普通野生稻miR160f的克隆和功能分析杨松楠;王姣;陈宗祥;田新杰;张静文;龙艳;裴新梧;袁潜华【摘要】MicroRNAs are a class of non-coding RNAs involved in post- transcriptional control of gene expression. Former study on Arabidopsis thaliana reveals that miR160 involves in root cell division and differentiation by regulating auxin response factors(ARF)thus influence the root development. This study cloned miR160f gene from common wild rice and transferred intoArabidopsis thaliana to identify its function. The results showed that over-expression of miR160f decreased the number of rosette leaves, shortened bloting time, leading to early flowering. RT-PCR showed the expressions of gene ARF10,ARF16 and ARF17 are down-regulation caused by miR160f in transgenic Arabidopsis thaliana, while the deficiency of ARF10 and ARF16 protein can inhibit root cap cell differentiation, lose control of cell division and lead to ectopic expansion of apical stem cell populations Therefore, the result demonstrates that miR160 not only influence on root development, but also may influence flowering time of common wild rice.%MicroRNAs是一类在调节基因转录后表达中起重要作用的非编码RNA。

microRNA调控动物发育的研究进展

microRNA调控动物发育的研究进展王丽娟;凌英会;张晓东;丁建平【摘要】microRNAs是一类长度约22 nt的内源性非编码小RNA分子,它能够通过与靶基因3＇非翻译区结合从而抑制靶基因的翻译或降解靶基因.microRNAs无论是在单细胞还是多细胞的真核生物中都广泛存在,并对生物体的细胞周期及个体发育过程进行调控.论文对microRNAs分子及其对动物的神经、心脏、皮肤、毛发和肌肉发育等方面的研究进展作一综述,以期为深入研究调控动物发育的各种microRNAs的功能奠定基础.%MicroRNAs are length of about 22nt non-coding small RNA molecules, which can combine the 3 ' untranslated region to stop the translation or degradation of target genes. The microRNAs exisit in a single cell or multicellular eukaryotes widely and regulate the cell cycle of the organism along with the process of ontogeny. The research about microRNAs and their effects on nerves, heart, skin, hair and muscle development of animal are reviewed, which may help deep research the function of microRNAs.【期刊名称】《家畜生态学报》【年(卷),期】2012(033)006【总页数】4页(P103-106)【关键词】microRNA;动物;发育;基因表达调控【作者】王丽娟;凌英会;张晓东;丁建平【作者单位】安徽农业大学动物科技学院,安徽合肥 230036;安徽地方畜禽遗传资源保护与生物育种省级实验室,安徽合肥 230036;安徽农业大学动物科技学院,安徽合肥 230036;安徽地方畜禽遗传资源保护与生物育种省级实验室,安徽合肥230036;安徽农业大学动物科技学院,安徽合肥 230036;安徽地方畜禽遗传资源保护与生物育种省级实验室,安徽合肥 230036;安徽农业大学动物科技学院,安徽合肥230036;安徽地方畜禽遗传资源保护与生物育种省级实验室,安徽合肥 230036【正文语种】中文【中图分类】S811.6microRNAs(miRNAs)是一段非常短的RNA非编码序列，它是在转录后水平来调控基因表达的一个重要因子。

微生物的作用英语作文

微生物的作用英语作文The Role of Microorganisms in Our World.Microorganisms, invisible to the naked eye, are present everywhere in our surroundings. These tiny beings, ranging from bacteria to fungi and protozoa, play a crucial role in maintaining the balance of our ecosystem. They are responsible for various processes that are essential forlife on Earth, including decomposition, nutrient cycling, and even the production of essential compounds for human use.Decomposition and Nutrient Cycling.Microorganisms are nature's recycling agents. They decompose organic matter, converting it into simple compounds that can be utilized by other organisms. Bacteria, fungi, and protozoa consume dead plant and animal matter, releasing carbon dioxide, water, and nutrients such as nitrogen, phosphorus, and sulfur. This process not onlyprevents the accumulation of organic waste but also ensures that nutrients are recycled back into the soil, maintaining soil fertility and supporting plant growth.Production of Compounds for Human Use.Microorganisms are also crucial for the production of various compounds used by humans. These include antibiotics, vitamins, enzymes, and biofuels. Antibiotics, produced by certain bacteria, are essential for treating infections caused by other microorganisms. Vitamins, such as vitamin C produced by certain bacteria and yeasts, are necessary for maintaining human health. Enzymes, produced by microorganisms, are widely used in industries for various catalytic reactions. Furthermore, microorganisms can beused to produce biofuels like bioethanol and biodiesel, which are renewable energy sources with lower environmental impacts compared to fossil fuels.Role in the Immune System.Microorganisms also play a role in training andstimulating our immune system. By exposing us to harmless microorganisms, our immune system learns to recognize and respond to foreign invaders, thus protecting us from diseases. This process, known as immune priming, is crucial for the development of a strong immune system.Environmental Remediation.Microorganisms can also be used for environmental remediation, i.e., cleaning up contaminated sites. For example, certain bacteria can break down toxic chemicals, converting them into less harmful compounds. This bioremediation process can be used to clean up oil spills, industrial waste, and even radioactive contaminants.Agricultural Applications.In agriculture, microorganisms play a vital role in crop production. They help improve soil fertility by fixing nitrogen, releasing phosphorus, and producing other essential nutrients. Microorganisms also aid in the decomposition of crop residues, thus preparing the soil forthe next crop. Furthermore, certain microorganisms can be used as biofertilizers and biopesticides, providing an eco-friendly alternative to chemical fertilizers and pesticides.Future Prospects.With the advent of biotechnology, microorganisms are becoming increasingly important in various fields such as medicine, agriculture, and energy production. Future research in this area could lead to the development of more efficient microbial strains for bioremediation, biofuel production, and other applications. Additionally, microorganisms could play a crucial role in the development of new drugs and therapies for treating diseases that are currently resistant to antibiotics.In conclusion, microorganisms, despite their small size, play a pivotal role in maintaining the balance of our ecosystem. They are essential for processes such as decomposition, nutrient cycling, and the production of compounds for human use. Furthermore, they play a crucial role in training our immune system, environmentalremediation, and agricultural production. As we continue to explore the wonders of these tiny beings, we stand to benefit immensely from their incredible diversity and functionality.。

动物病毒microRNA的研究进展

动物病毒microRNA的研究进展薛白;王树芬;鲍登克;邓瑞广;李学伍【摘要】MicroRNAs (miRNAs)是一种含有约22～25个核苷酸的非编码单链RNA分子,广泛存在于人类及其他各种生物中.它通过与靶mRNA特异性的碱基互补配对,引起靶mRNA降解或者抑制其翻译,从而调节基因的转录后表达水平.病毒microRNA是新发现的一类miRNA,综述了近年来病毒microRNA的产生、作用机制、生物学功能及其在动物上的研究进展.%MicroRNAs(miRNAs)are a class of non-coding small RNA in length of 22 -25 nt and distribute extensively in human and other organism genomes. They regulate gene expression through sequence specific interactions with target mRNAs resulting in translational repression or mRNA degradation. Viral microRNAs are a class of newly discovered miRNA. This paper introduces the progress on the researches of the generation, functions and mechanisms of viral microRNAs and its function involved in animal diseas.【期刊名称】《河南农业科学》【年(卷),期】2012(041)006【总页数】4页(P15-18)【关键词】病毒;microRNA;基因调控;动物疾病【作者】薛白;王树芬;鲍登克;邓瑞广;李学伍【作者单位】河南科技大学动物科技学院,河南洛阳471003;河南省农业科学院农业部动物免疫学重点开放实验室/河南省动物免疫学重点实验室,河南郑州450002;河南科技大学动物科技学院,河南洛阳471003;河南省农业科学院农业部动物免疫学重点开放实验室/河南省动物免疫学重点实验室,河南郑州450002;河南省农业科学院农业部动物免疫学重点开放实验室/河南省动物免疫学重点实验室,河南郑州450002;河南省农业科学院农业部动物免疫学重点开放实验室/河南省动物免疫学重点实验室,河南郑州450002;河南省农业科学院农业部动物免疫学重点开放实验室/河南省动物免疫学重点实验室,河南郑州450002【正文语种】中文【中图分类】S852.65microRNA是一类长度介于22～25个碱基的非编码小分子RNA，在细胞发育与分化、细胞凋亡、脂肪代谢、组织器官形成、肿瘤发生、病毒感染等许多生物学过程中发挥重要的转录后基因调控功能［1］。

动物和植物作文800

动物和植物作文800Animals and PlantsIn the vast and diverse world, animals and plants coexist harmoniously, each playing a crucial role in maintaining the balance of nature. Animals, with their diverse forms and behaviors, bring vitality and dynamism to the world, while plants, with their static beauty and essential ecological functions, provide the foundation for life.Animals are the epitome of life's diversity. From the tiny ants that scurry about busily to the majestic elephants that roam the plains, each animal species possesses its unique characteristics and survival strategies. They engage in intricate social interactions, displaying cooperation, competition, and even empathy. Animals also serve as indicators of environmental health, often being the first to suffer when ecosystems are disrupted.Plants, on the other hand, are the silent guardians of the planet. They transform sunlight into energy through photosynthesis, providing the fundamental source of food for nearly all life on Earth. Their roots anchor the soil, preventing erosion and maintaining fertility. Plants also purify the air, absorbing carbon dioxide and releasing oxygen, thus contributing to a healthier environment.The relationship between animals and plants is intricate and symbiotic. Many animals depend on plants for food, either directly through herbivory or indirectly through predation on herbivores. Conversely, plants rely on animals for pollination and seed dispersal. This mutual dependency creates a delicate balance that, when disrupted, can have far-reaching consequences for both animals and plants.However, the harmonious coexistence of animals and plants is increasingly threatened by human activities. Deforestation, pollution, and climate change are just a few of the many challenges that these living beings face. As a result, many species are endangered or even facing extinction.It is our responsibility to protect and preserve the diverse world of animals and plants. We must adopt sustainable practices, reduce our impact on the environment, and conserve biodiversity. By doing so, we not only safeguard the future of these remarkable creatures but also ensure the health and sustainability of our own planet.In conclusion, animals and plants are integral parts of our world, each playing a crucial role in maintaining the balance of nature. Their diversity, beauty, and ecological functions enrich our lives and contribute to the overall health of our planet. It is our duty to cherish and protect them, ensuring that they thrive and continue to bring joy and sustenance to future generations.动物与植物在广阔且多样化的世界中，动物与植物和谐共存，各自在维持自然平衡中发挥着至关重要的作用。

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REVIEW
Role of MicroRNAs in Plant and Animal Development
James C. Carrington1* and Victor Ambros2
Small RNAs, including microRNAs (miRNAs) and short interfering RNAs (siRNAs), are key components of an evolutionarily conserved system of RNA-based gene regulation in eukaryotes. They are involved in many molecular interactions, including defense against viruses and regulation of gene expression during development. miRNAs interfere with expression of messenger RNAs encoding factors that control developmental timing, stem cell maintenance, and other developmental and physiological processes in plants and animals. miRNAs are negative regulators that function as speciﬁcity determinants, or guides, within complexes that inhibit protein synthesis (animals) or promote degradation (plants) of mRNA targets.
1Center for Gene Research and Biotechnology, and Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA. 2Department of Genetics, Dartmouth Medical School, Hanover, NH 03755, USA. *To whom correspondence should be addressed. Email: carrington@
References and Notes 1. A. Allsopp, Adv. Morphol. 6, 127 (1967). 2. R. S. Poethig, Science 250, 923 (1990). 3. A. Mouradov, F. Cremer, G. Coupland, Plant Cell 14
SPECIAL SECTION
DEVELOPMENTAL TIMING
ferent phases of vegetative development; the third regulates the differentiation of reproductive structures. The temporal sequence of these differentiation programs is regulated by threshold responses to graded environmental stimuli, such as light quality and endogenous spatial and temporal information. Differentiation programs are synchronized with organ production and growth via the effect of these programs on cell division and cell expansion, and by a thermal clock that is shared by all of these programs.