Schuwerack P M, Lewis J W, Jones P W
School of Biological Sciences, University of London, Royal Holloway, Surrey, TW20 0EX, United Kingdom.
J Invertebr Pathol. 2001 May;77(4):269-79. doi: 10.1006/jipa.2001.5023.
The impact of microbial gill infestations on the pathology and physiology of the freshwater crab Potamonautes warreni was investigated by comparison of infested and uninfested crab populations from, respectively, a polluted and an unpolluted site along the Mooi River, North West Province, South Africa. Heavy gill infestations by bacteria (70%), peritrichous ciliates such as Lagenophrys sp. (15%), Zoothamnium sp. (10%), and Epistylis sp. (5%), and motile protozoans resulted in species-specific lesions in the gill epithelia of P. warreni and physiological changes in crabs from the polluted site. Bacterial colonies enmeshed in polysaccharide-like films produced indentations of the gill cuticular surfaces and dissociation of microvillous membranes at the basal zone of epithelial cells of gill lamellae of P. warreni. Lagenophrys sp. induced large subcuticular spaces with an unfolding or resorption of the plasma membrane in the gill epithelia. The attachment of stalks of Zoothamnium and Epistylis resulted in dilation of lamellar tissues, the formation of vacuoles, and an increase in subcuticular spaces in the epithelia. Physiological changes in infested crabs included significant differences (P = 0.001) in increments of wet body mass and a reduced growth rate over time compared with uninfested crabs. The specific oxygen consumption (M(O2)) in rested infested crabs significantly increased (31.29 +/- 5.8 micromol O2/kg/min) compared with the M(O2) in uninfested crabs (27.92 +/- 5.6 micromol O2/kg/min; P = 0.009). The heart rate of infested rested P. warreni was significantly lower (40.77 +/- 13.79 beats/min; P < 0.02) than that in uninfested crabs (61.09 +/- 29.02 beats/min) but the heart rate of infested crabs increased significantly with body mass (r = 0.53, P = 0.02). These findings suggest an interrelationship among organic pollution, microbial gill infestations, and specific pathological and physiological responses in the crab host. The role of P. warreni and its microbial gill communities as bioindicators of pollution are discussed.
通过比较分别来自南非西北省莫伊河一个污染地点和一个未受污染地点的受感染和未受感染的淡水蟹种群，研究了微生物鳃感染对沃氏溪蟹（Potamonautes warreni）病理和生理的影响。细菌（70%）、诸如拉氏纤毛虫（Lagenophrys sp.，15%）、聚缩虫（Zoothamnium sp.，10%）和累枝虫（Epistylis sp.，5%）等周丛生纤毛虫以及活动的原生动物的严重鳃感染，导致了沃氏溪蟹鳃上皮出现物种特异性病变以及来自污染地点的螃蟹出现生理变化。包裹在多糖样膜中的细菌菌落使沃氏溪蟹鳃表皮表面产生凹痕，并使鳃小片上皮细胞基底部的微绒毛膜解离。拉氏纤毛虫在鳃上皮中诱导形成大的皮下间隙，并伴有质膜展开或吸收。聚缩虫和累枝虫的柄附着导致鳃组织扩张、液泡形成以及上皮中皮下间隙增加。与未受感染的螃蟹相比，受感染螃蟹的生理变化包括湿体重增加存在显著差异（P = 0.001）以及随时间推移生长速率降低。与未受感染螃蟹的耗氧率（27.92±5.6微摩尔O₂/千克/分钟；P = 0.009）相比，休息状态下受感染螃蟹的特定耗氧率（M(O₂)）显著增加（31.29±5.8微摩尔O₂/千克/分钟）。休息状态下受感染的沃氏溪蟹的心率显著低于未受感染螃蟹（40.77±13.79次/分钟；P < 0.02）（61.09±29.02次/分钟），但受感染螃蟹的心率随体重显著增加（r = 0.53，P = 0.02）。这些发现表明有机污染、微生物鳃感染以及螃蟹宿主中特定的病理和生理反应之间存在相互关系。讨论了沃氏溪蟹及其鳃微生物群落作为污染生物指示物的作用。
