中国林蛙的分类及分布

目的中国林蛙(Rana chensinensis David,1875)是我国林蛙属分布最为广泛的特有种,在上一世纪对其分类问题多有争议,曾被认为广布于中国、蒙古、俄罗斯、日本和朝鲜半岛等。随着对其分类地位的确定,其分布范围也发生了很大变化。为了保护和可持续利用这一重要资源,本文对其分类研究历史和分布进行了总结。方法通过收集、整理和分析研究文献,结合本实验室多年来掌握的野外资料,进行系统的总结。结果中国林蛙自1875年由戴维(中文名为谭卫道)命名以来,曾被划归欧洲林蛙的亚种,并将多种其他林蛙归并入其下。1981年,经过细胞分类学研究,正式恢复为有效种,随后进一步划分出5个亚种。直至本世纪初,经过进一步的分类学研究,厘清了其与东北林蛙和西北林蛙的关系,从而确定其为仅分布于中国的特有种。在此基础上,对其分布也进行了重新确立。结论中国林蛙隶属于蛙科林蛙属中国林蛙种组,目前没有种下分化和亚种形成,分布于我国华北、华中及其周边地区,分布海拔不高于2500m。     

Ninjurin1 Enhances the Basal Motility and Transendothelial Migration of Immune Cells by Inducing Protrusive Membrane Dynamics

Ninjurin1 is involved in the pathogenesis of experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis, by mediating leukocyte extravasation, a process that depends on homotypic binding. However, the precise regulatory mechanisms of Ninjurin1 during inflammation are largely undefined. We therefore examined the pro-migratory function of Ninjurin1 and its regulatory mechanisms in macrophages. Interestingly, Ninjurin1-deficient bone marrow-derived macrophages exhibited reduced membrane protrusion formation and dynamics, resulting in the impairment of cell motility. Furthermore, exogenous Ninjurin1 was distributed at the membrane of filopodial structures in Raw264.7 macrophage cells. In Raw264.7 cells, RNA interference of Ninjurin1 reduced the number of filopodial projections, whereas overexpression of Ninjurin1 facilitated their formation and thus promoted cell motility. Ninjurin1-induced filopodial protrusion formation required the activation of Rac1. In Raw264.7 cells penetrating an MBEC4 endothelial cell monolayer, Ninjurin1 was localized to the membrane of protrusions and promoted their formation, suggesting that Ninjurin1-induced protrusive activity contributed to transendothelial migration. Taking these data together, we conclude that Ninjurin1 enhances macrophage motility and consequent extravasation of immune cells through the regulation of protrusive membrane dynamics. We expect these findings to provide insight into the understanding of immune responses mediated by Ninjurin1.     

Biodiversity patterns of nutrient-rich fish ponds and implications for conservation

Nutrient-rich water bodies are usually expected to host low species richness at the local scale (water body). Nevertheless, they can support a diverse and sometimes unique biodiversity when diversity is considered at a regional scale. This discrepancy between the two scales is well documented for natural water bodies, but little is known about biodiversity of artificial water bodies, like fish ponds. We hypothesise that nutrient-rich water bodies can collectively host high species richness at the regional scale. Thus, these are important ecosystems for the regional conservation of biodiversity. We investigated 84 fish ponds in the Dombes region, France, with five taxonomic groups: macrophytes, phytoplankton, macroinvertebrates, dragonflies, and amphibians. Species richness patterns were determined for α- (single pond), β- (between ponds), and γ- (regional pond network) levels. For most studied species groups, richness per fish pond and at the regional level proved to be relatively high in comparison with natural ponds in other landscapes. Contribution of α-diversity to regional diversity was highest for dragonflies with 41 %, and lowest for amphibians and macrophytes with 16 and 18 %, respectively. For macroinvertebrate families and phytoplankton genera it was intermediate. Contribution of β-diversity to regional diversity was similar for all species groups with 22–25 %. Furthermore, some ponds hosted a large number of less frequent species and some endangered species, indicating that the conservation of biodiversity of fish ponds must be established at a regional scale.     

Toxicity to cotton boll weevil Anthonomus grandis of a trypsin inhibitor from chickpea seeds

Cotton (Gossypium hirsutum L.) is an important agricultural commodity, which is attacked by several pests such as the cotton boll weevil Anthonomus grandis. Adult A. grandis feed on fruits and leaf petioles, reducing drastically the crop production. The predominance of boll weevil digestive serine proteinases has motivated inhibitor screenings in order to discover new ones with the capability to reduce the digestion process. The present study describes a novel proteinase inhibitor from chickpea seeds (Cicer arietinum L.) and its effects against A. grandis. This inhibitor, named CaTI, was purified by using affinity Red-Sepharose Cl-6B chromatography, followed by reversed-phase HPLC (Vydac C18-TP). SDS-PAGE and MALDI-TOF analyses, showed a unique monomeric protein with a mass of 12,877 Da. Purified CaTI showed significant inhibitory activity against larval cotton boll weevil serine proteinases (78%) and against bovine pancreatic trypsin (73%), when analyzed by fluorimetric assays. Although the molecular mass of CaTI corresponded to alpha-amylase/trypsin bifunctional inhibitors masses, no inhibitory activity against insect and mammalian alpha-amylases was observed. In order to observe CaTI in vivo effects, an inhibitor rich fraction was added to an artificial diet at different concentrations. At 1.5% (w/w), CaTI caused severe development delay, several deformities and a mortality rate of approximately 45%. These results suggested that CaTI could be useful in the production of transgenic cotton plants with enhanced resistance toward cotton boll weevil.     

Comparative study of Bifidobacteriumanimalis, Escherichiacoli, Lactobacilluscasei and Saccharomycesboulardii probiotic properties

The present work investigates some probiotic properties of four different microorganisms (Bifidobacterium animalis var. lactis BB-12, Escherichia coli EMO, Lactobacillus casei and Saccharomyces boulardii). In vitro and in vivo tests were carried out to compare cell wall hydrophobicity, production of antagonistic substances, survival capacity in the gastrointestinal tract of germ-free mice without pathological consequence, and immune modulation by stimulation of Küpffer cells, intestinal sIgA and IL-10 levels. In vitro antagonism against pathogenic bacteria and yeast was only observed for the probiotic bacteria B. animalis and L. casei. The hydrophobic property of the cell wall was higher for B. animalis and E. coli EMO, and this property could be responsible for a better ability to colonize the gastrointestinal tract of germ-free mice. Higher levels of sIgA were observed mainly for S. boulardii, followed by E. coli EMO and B. animalis, and only S. boulardii induced a significant higher level of IL-10. In conclusion, for a probiotic use, S. boulardii presented better characteristics in terms of immunomodulation, and B. animalis and L. casei for antagonistic substance production. The knowledge of the different probiotic properties could be used to choice the better microorganism depending on the therapeutic or prophylactic application.     

Sialylation of Campylobacter jejuni lipo-oligosaccharides is associated with severe gastro-enteritis and reactive arthritis

We used various genotyping methods to identify bacterial genetic markers for development of arthritic symptoms following Campylobacter enteritis. We genotyped a collection of population derived Campylobacter strains, with detailed information on clinical characteristics, including arthritic symptoms. Besides using whole genome screening methods, we focused on the lipo-oligosaccharide (LOS) gene locus in which marker genes for developing post-Campylobacter neurological disease are present. Patients with arthritic symptoms were more frequently infected with Campylobacter jejuni strains with a class A LOS locus. We also found that patients who were infected with a C. jejuni strain containing sialic acid-positive LOS (class A, B or C) more frequently had bloody diarrhoea and a longer duration of symptoms. Furthermore, the IgM antibody response against Campylobacter was stronger in patients with a sialic acid containing LOS. Ganglioside auto-antibodies were observed in a small number of patients following infection with a class C strain. We conclude that sialylation of C. jejuni LOS is not only a risk factor for development of post-infectious symptoms, but is also associated with increased severity of enteric disease.