[Detection of the quorum sensing signals in methanogenic archaea].

Unlabelled: Methanosaeta harundinacea 6Ac displayed a cell-density dependent cell morphology transition between short rods (3 microm - 5 microm) and filaments ( >200 microm), implying a quorum sensing system in this archaeon.

Objective: This study aimed to confirm that cell morphology related quorum sensing exists in Methanosaeta harundinacea.

Methods: By using the bioassay of Agrobacterium tumefaciens NTL4, we determined the presence of acyl homoserine lactones (AHLs) in the spent cultures of Methanosaeta harundinacea 6Ac and other three methanogens.

Main nutrients, phenolics, antioxidant activity, DNA damage protective effect and microstructure of Sphallerocarpus gracilis root at different harvest time.

Sphallerocarpus gracilis roots harvested at two different times (T1: 12-10-2009 and T2: 15-04-2010) were analysed for their main nutrients, phenolics, antioxidant activity, DNA damage protective effect and microstructure. Results revealed that higher amounts of starch were detected in T1 S. gracilis root, whereas higher levels of reducing sugar, protein, amino acids and phenolic compounds were determined in T2 S.

Methanogen community in Zoige wetland of Tibetan plateau and phenotypic characterization of a dominant uncultured methanogen cluster ZC-I.

Zoige wetland of Tibetan plateau is characterized by being located at a low latitude (33 degrees 56'N, 102 degrees 52'E) region and under the annual temperature around 1 degrees C. Previous studies indicated that Zoige wetland was one of the CH(4) emission centres in Qinghai-Tibetan plateau; in this study, the methanogen community in this low-latitude wetland was analysed based on the homology of 16S rRNA and mcrA genes retrieved from the soil. The results indicated that members of Methanosarcinales and Methanomicrobiales constituted the majority of methanogens, and a novel uncultured methanogen cluster, Zoige cluster I (ZC-I) affiliated to Methanosarcinales, could be dominant.

[Wolbachia extensively harbored by Bemisia tabaci in China].

Wolbachia are a group of maternally inherited bacteria harbored by a variety of arthropods and can manipulate the reproductivity of their hosts. Eighteen populations of whiteflies were collected from Hebei, Xinjiang, Beijing, Shandong, Zhejiang, Guangxi, Hainan, Guangzhou and Fujian provinces, China. These whiteflies were molecularly identified using internal transcribed spacer 1 ITS1 rDNA sequences.

Prevalence of Wolbachia infection in Bemisia tabaci.

Wolbachia are obligate intracellular bacteria present in reproductive tissues of many arthropod species. It has been reported that few silverleafing populations of Bemisia tabaci were positive for Wolbachia, whereas non-silverleafing populations were more likely infected with Wolbachia and all that infect B. tabaci are Wolbachia belonging to supergroup B.