Studies on rumen methanogens associated with ciliates

研究了瘤胃产甲烷菌的作用、生态位及其与瘤胃纤毛虫的关系。澄清了以下几点。(1)投喂后，与纤毛虫共生的产甲烷菌数量显著增加，投喂后3h降至投喂前水平。数量的快速增加和减少表明甲烷种群的存在，根据纤毛虫的代谢活动，附着在纤毛虫表面并从纤毛虫表面离开。甲烷菌的耐氨性和对氯化钠的依赖性在纤毛虫伴生和非伴生种群之间存在差异。(2)表观甲烷生产纤毛虫原生动物显然是依赖于属。等毛藓属在测试的属中产生最多的甲烷。而Polyplastron spp.和Epidinium spp.产生少量甲烷。(3)产甲烷菌与纤毛虫之间的关系是种间氢转移。经过测试， ...更多信息 这种关系可以被其他氢营养细菌所取代。脱硫弧菌SR3和瘤胃产乙酸菌Ser5与瘤胃纤毛虫建立了共培养关系。底物降解纤毛虫没有显着刺激，但是。(4)从纤毛虫中分离出11株以上的产甲烷菌，它们大多具有相似的形态特征。对其中一个革兰氏阳性球菌和一个革兰氏阳性杆菌进行了进一步的底物和生理特性试验。这两种分离物使用氢和甲酸作为电子供体。氯化钠的依赖性和氨的耐受性的两个菌株是相似的，而不同的纤毛虫相关的产甲烷种群中观察到的。这些菌株可能不是内共生产甲烷菌，而是附着在纤毛表面的产甲烷菌。用16SrDNA引物对这些菌株以及与产甲烷菌相关的纤毛虫群体进行PCR分析，由于没有得到该引物的扩增产物，因此表明产甲烷菌在纤毛虫上和纤毛虫中与已知的产甲烷菌存在遗传差异。少

Roles and niche or ruminal methanogens were investigated with special reference to their relation to rumen ciliate protozoa. Following points were clarified.(1) Number of methanogens associated with ciliates significantly increased after feeding, then declined to pre-feeding level 3 h after feeding. Rapid increases and decrease in numbers suggested the presence of methanogenic population which attaches on and leaves from ciliate surfaces according to the metabolic activity of ciliates. Difference in ammonia tolerance and sodium chloride dependence of methanogens was observed between ciliate associated and non-associated populations. (2) Apparent methane productions from ciliate protozoa were apparently genus-dependent. Isotricha spp. produced the largest amount of methane among genera tested. While Polyplastron spp. and Epidinium spp. produced small amount of methane. (3) Relation between methanogens and ciliate is characterized as interspecies hydrogen transfer. It was tested if this … More relation could be replaced by other hydrogenotrophic bacteria. Desulfovibrio sp. SR3 and ruminal acetogen Ser 5 established cocultures with rumen ciliates in consuming hydrogen. Substrate degradation by ciliate was not significantly stimulated, however. (4) More than 11 methanogens were isolated from ciliates, most of them had similar morphological features. One gram positive cocoid and one gram positive rod were further tested their substrates and some physiological characteristics. Both isolates used hydrogen and formate as electron donors. Sodium chloride dependence and ammonia tolerance of both isolates were similar and differed from those observed in ciliate associated methanogenic population. These isolates may not be endosymbiotic methanogens but the methanogens attached on the ciliate surfaces. DNA analysis on these isolates as well as ciliate associated methanogenic population by PCR using the primer sets for 16Sr DNA of alchaea suggested the genetical difference of methanogen on and in ciliate from known alchaea, because no amplified product was obtained with this alchaea specific primer set. Less