羊粪低温沼气发酵细菌群落多样性分析

[目的]研究不同处理羊粪低温沼气发酵液的细菌群落多样性,为羊粪低温沼气发酵菌剂制备提供理论依据.[方法]对不同处理羊粪沼液总DNA进行16S rDNA V3区PCR扩增,扩增产物进行变性梯度凝胶电泳(DGGE)分离、回收、测序,BLAST软件比对分析,构建发育树;同时利用Biolog-ECO法对沼液样本进行微生物功能多样性分析.[结果]PCR-DGGE方法结果显示,在低温条件下(15℃),在发酵各阶段均存在共有优势菌群,包括梭菌属(Clostridium sp.)、拟杆菌属(Bacteroidales bacterium)、假单胞菌属(Pseudomonas sp.)、Proteiniphilum sp.等,其中菌剂Ⅲ处理的4号为最优发酵试验组,主要为梭菌属(Clostridium sp.)表现有较高的丰度;Biolog-ECO法分析结果显示,在15℃培养条件下,产气高峰期处理2、3和4中,碳代谢活性相对较高,产气量也比对照组高.通过微生物群落的多样性分析发现,处理2的均匀性指数均高于其它处理组.处理3和4的微生物群落的丰富度、优势度指数相对较高.[结论]在低温条件下(15℃)的不同处理中,添加配伍Ⅲ(配伍Ⅰ+2 9 ZHC固体菌剂)发酵效果最优.     

Diffuse leptomeningeal histiocytic sarcoma in the cerebrospinal fluid of 2 dogs

Two adult male castrated dogs were evaluated for progressive paraparesis and ataxia. Neurologic examination showed severe ataxia, delayed proprioceptive placement in the pelvic limbs, pain upon palpation of the lumbar spine as well as facial paresis in one dog, and decreased withdrawal reflex of the pelvic limbs in the other dog. Magnetic resonance imaging (MRI) in both dogs showed diffuse meningeal and intramedullary lesions. However, no evidence of a mass was found. Biopsies could not be performed safely due to the location of the lesions. Cerebrospinal fluid (CSF) examination revealed an inflammatory pleocytosis associated with increased protein concentration and numerous large atypical round cells, often multinucleated. Nuclear fragmentation, micronuclei, and rare atypical mitoses were observed. Immunocytochemistry revealed CD1⁺ and CD11c⁺ staining, which, in concert with the morphology confirmed the diagnosis of histiocytic sarcoma (HS). Euthanasia was elected due to poor prognosis. Histopathologic examination showed diffuse spinal and meningeal infiltration with CD18⁺ neoplastic cells, without any evidence of mass formation, which completed the diagnosis of diffuse leptomeningeal HS involving the brain and the spinal cord. Canine central nervous system (CNS) HS has been seldom reported in the literature, with only isolated cases identified on CSF cytology. The cases reported here are remarkable in describing a diffuse CNS leptomeningeal HS associated with neoplastic cells in the CSF of dogs without a tumor mass. These cases emphasize the potential critical importance of CSF analysis in providing an antemortem diagnosis of neoplasia in neurologic patients.