Interaction of Xenorhabdus nematophilus (Enterobacteriaceae) with the antimicrobial defenses of the house cricket, Acheta domesticus.
Interaction of Xenorhabdus nematophilus (Enterobacteriaceae) with the antimicrobial defenses of the house cricket, Acheta domesticus.
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嗜线杆菌（肠杆菌科）与家蟋蟀抗菌防御的相互作用。
DOI：
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发表时间：
2000
影响因子：
3.4
通讯作者：
M. Rau
中科院分区：
文献类型：
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作者：
C. Da Silva;G. Dunphy;M. Rau
在接触死的嗜线虫后的第一个小时内，五龄家蚕若虫的总血细胞计数出现下降；在此期间，血淋巴中的细菌水平也有所下降。此后，随着受损血细胞水平的增加，血淋巴中的细菌数量也随之增加。细菌通过最初减少含有酚氧化酶原的血细胞数量，后来通过抑制酶的激活来降低体内酚氧化酶的活性。体外用活性酚氧化酶在血淋巴中预孵育嗜线虫线虫，在体内加速了细菌从血淋巴中的清除，这可能是由于丝氨酸蛋白酶修饰了细菌表面。在注射细菌的昆虫中，溶菌酶活性的增加与受损血细胞数量的增加并行；大部分酶位于血细胞中。嗜线虫线虫的脂多糖引起血细胞计数、酚氧化酶和溶菌酶水平的变化，与整个细菌相当。脂多糖还减缓了细菌从血淋巴中清除的速度，并加速了细菌进入血淋巴的速度。
Fifth instar Acheta domesticus nymphs exhibited a decline in total hemocyte counts during the first hour of exposure to dead Xenorhabdus nematophilus; the bacterial level in the hemolymph also declined during this time. Thereafter bacterial numbers in the hemolymph increased as the level of damaged hemocytes increased. The bacteria lowered phenoloxidase activity in vivo by initially reducing the number of hemocytes containing prophenoloxidase and later by inhibiting enzyme activation. Preincubating X. nematophilus in hemolymph with active phenoloxidase in vitro accelerated the removal of the bacteria from the hemolymph in vivo which may be due to modification of the bacterial surface by serine proteases. Lysozyme activity increased in bacteria-injected insects in parallel with an increase in counts of damaged hemocytes; most of the enzyme was located in hemocytes. Lipopolysaccharides of X. nematophilus caused changes in hemocyte counts and phenoloxidase and lysozyme levels comparable to whole bacteria. Lipopolysaccharides also slowed the removal rate of the bacteria from, and accelerated bacterial emergence into, the hemolymph.