微生物大题-英文

2.Pass mechanism of cholera pathogenic:霍乱

1)pathogenic factor:

invasiveness: flagellum, pili;

cholera enterotoxin: contain A and B subunits. A subunit-Ag weak, active unit, enters the cell, stimulates adenylate cyclase-cAMP↑-secreting effect↑-severe diarrhea; B subunit-Ag high, bound unit, attaches to receptor on epithelial cells of small intestine.

2)mechanism:

Organisms-oral route(contaminated water, food)-stomach-attach to the small intestine epithelialcells(non-penetration)-multiplication-cholera enterotoxin-adenylate cyclase-cAMP concentration↑-secreting effect↑-severe diarrhea(rice-water stools)-rapid dehydration and hypovolaemic shock低血容量休克-die in 12~24 hours. Ps. Transmission: polluted water and food, by mouth

3.Pass Clostridium tetani- pathogenesis破伤风

1)condition:

Wound+spore

Deep, narrow and contaminated by soil;

Necrotic坏死的tissue;

Companied with aerobe or facultative anaerobe infection.

2)pathogenic substance:

Tetanospasmin破伤风痉挛毒素- neurotoxin: protein

Tetanolysin破伤风溶血毒素

3)mechanism:根据课件整理一下

Spores-vegetative bacteria细菌繁殖体-grow locally-tetanospasmin-( along nerve fiber/ blood)-anterior horn cells of spinal cord, binds to ganglioside receptor神经节苷酯受体and blocks release of inhibitory mediators-cause convulsive痉挛的contraction of voluntary muscle.

4.Pass dsDNA病毒的复制周期

答：复制周期依次包括：吸附。穿入。脱壳。生物合成。组装、成熟和释放。Replication cycle: adsorption-penetration-uncoating-biomolecular synthesis-assembly-maturation-release

5.Pass HIV致病机制：

Pathogenesis:

Gp120 of HIV select CD4 molecule of T4 cells;

Viruses multiply in T4 cells;

Cell-mediated immunodeficiency;

Opportunistic infections and tumor occurs;

Death

HIV损伤CD4 T细胞的机制：①导致CD4 T细胞融合，最终导致细胞的溶解；

②CTL对CD4 T细胞的直接杀伤作用，抗体介导的ADCC作用，NK细胞的杀伤作用；

③诱导CD4 T细胞细胞凋亡；④HIV复制产生大量未整合的病毒DNA，抑制细胞正常的生物合成；⑤HIV可作为超抗原激活大量CD4 T细胞。6，gp41与细胞

膜上MHC二类分子有同源性homology，诱导产生具有交叉反应的自身抗体，致使T细胞损伤。

Destruction of T4 cells is achieved by:

① Viral replication

②Syncytium合胞体formation via membrane gp120 binding to cell CD4 antigen

③Cytotoxic T cell lysis of infected cells

④Cytotoxic T cell lysis of T4 cells carrying gp120 released from infected cells

⑤ Antibody-dependent cell cytotoxicity.

⑥Induce appoptosis.

8.Pass functions of special cell structure of bacteria:

1) capsule: slime layer outside the cell wall, composed of polysaccharide or polypeptide.

Functions: anti-phagocytosis; adherence; protect from lesions by harmful substances; anti-dry; antigenicity

2) flagellum: originate from cell membrane

Functions: motility; antigenicity(H antigen); pathogenicity: some bacteria

3) pilus:

Common pilus: adhere to surface of cell, associated with pathogenicity

Sex pilus: transfer genetic material (DNA) during bacteria conjugation

4) spore: resting form, forming: inadequate nutrition

Function: highly resistant to heat, chemicals, dry