类菌体

苜蓿根瘤菌在与宿主植物建立共生关系的过程中，以自生状态进入宿主植物细胞，经过分化发育转变为共生状态的类菌体（Bacteroid）。

During the establishment process of symbiotic relation of alfalfa rhizobium with host plant , alfalfa rhizobium ( Sinorhizobium melitoti ) entered into host plant cell as self-growing state , and then transferred into bacteroid of symbiotic state through its differentiation development .

成熟类菌体外型较大，形态多样，细胞内聚-β-羟基丁酸（PHB）累积增多；

The mature bacteroid was large , its morphotypes were diversity , and the accumulated PHB increased in the bacteroids .

幼年美菌体为椭圆形，里面有个拟核区，正常类菌体有完整的周膜和PHB颗粒。

The younger bacteroid was elliptic and had a similar nucleus region in cell . The normal bacteroid had an intact membrane envelope and PHB granules .

灰金合欢根瘤类菌体繁殖及其宿主细胞的超微结构

Ultrastructure of host cells and FISSUS bacteroid in Acacia glauca nodules

在周膜内，类菌体经细胞分裂逐渐形成几个类菌体，这就是发展成熟根瘤共生细胞结构的形态特征。

This is the characteristic development of the mature structure of symbiotic nodular cells .

随着根瘤和其中类菌体的发育，根瘤固氮活性逐渐上升。

In the senescence stage of nodule , the bacteroidsautolyzed and nitrogenase activity disappeared .

类菌体呼吸作用的有效基质，即是类菌体固氮作用的有效能源。

The utilizable respiratory substrates were the effective energy sources of symbiotic nitrogen fixation of bacteroids .

在根瘤衰老细胞中，类菌体包被周膜解离破裂，流出电子透明物质。

It was observed that bacteroid was broken and it effused electron-transparent substance ( PHB ) in old nodule cell .

电镜图象表示，成熟根瘤的内皮层细胞中存在大量菌丝与泡囊，少数感染细胞产生大量多态形的拟类菌体细胞。

Electron micrographs show that the hyphae , vesicles and bacteria-like cells were observed in the endodermis-cells of root nodules .

在此，寄主在类菌体膜中把根瘤菌包裹起来，并形成与根的维管束连接。

There , the host envelopes the rhizobia in a peribacteriod membrane and connections to the root vascular system are formed .

此时，类菌体中许多与共生相关的基因被激活，蛋白的表达量显著增加。

At the moment , a number of relevant genes in the bacteroid related to the symbiosis were activated , and the expressed quantity of protein remarkably increased .

对检出的各fimA基因型P.结论：牙龈卟啉单胞菌菌毛蛋白FimA能与福赛斯类杆菌菌体蛋白相互结合，两者结合为碳水化合物-蛋白质凝集素样机制。

CONCLUSION : P.gingivalis FimA interacts with surface protein of B.forsythus , and the inter-bacterial binding mechanism between them may be lectin-carbohydrate .