Diversity and function of rhizosphere microorganisms between wild and cultivated medicinal plant Glycyrrhiza uralensis Fisch under different soil conditions.

Glycyrrhiza uralensis Fisch is a widely cultivated traditional Chinese medicine plant. In the present study, culture-independent microbial diversity analysis and functional prediction of rhizosphere microbes associated with wild and cultivated G. uralensis Fisch plant (collected from two locations) were carried. Soil physicochemical parameters were tested to assess their impact on microbial communities. A total of 4428 OTUs belonging to 41 bacterial phyla were identified. In general, cultivated sample sites were dominated by Actinobacteria whereas wild sample sites were dominated by Proteobacteria. The alpha diversity analysis showed the observed species number was higher in cultivated soil samples when compared with wild soil samples. In beta diversity analysis, it was noticed that the weighted-unifrac distance of two cultivated samples was closer although the samples were collected from different regions. Functional annotation based on PICRUST and FAPROTAX showed that the nitrogen metabolism pathway such as nitrate reduction, nitrogen fixation, nitrite ammonification, and nitrite respiration were more abundant in rhizosphere microorganisms of wild G. uralensis Fisch. These results also correlate in redundancy analysis results which show correlation between NO3--N and wild samples, which indicated that nitrogen nutrition conditions might be related to the quality of G. uralensis Fisch.

Chicken-type lysozyme functions in the antibacterial immunity in red swamp crayfish, Procambarus clarkii.

Lysozymes possess antibacterial activities, making them crucial defense proteins in innate immunity. In this study, a chicken-type (c-type) lysozyme (designated PcLyzc) was cloned and characterized from red swamp crayfish Procambarus clarkii. The full-length cDNA had an open reading frame of 435 base pairs encoding a polypeptide of 144 amino acid residues. Multiple alignments and phylogenetic analysis revealed that PcLyzc shared high similarity to the other known invertebrate c-type lysozymes. PcLyzc transcripts were steadily expressed in a wide range of tissues in healthy crayfish, and were prominently up-regulated in the hepatopancreas and gills after Vibrio anguillarum or Aeromonas hydrophila challenge. Recombinant PcLyzc showed inhibitory activity in vitro against both Gram-positive bacteria, including Staphylococcus aureus, Micrococcus luteus and Bacillus thuringiensis, and Gram-negative bacteria, including A. hydrophila, V. anguillarum and Escherichia coli. By overexpressing PcLyzc through introducing exogenous recombinant protein, or silencing PcLyzc expression through injecting double strand RNA, it was found that PcLyzc could help eliminate the invading bacteria in crayfish hemolymph and could protect crayfish from death, possibly by promoting the hemocytic phagocytosis. These results indicated that PcLyzc played a role in the antibacterial immunity of crustaceans, and laid a foundation of developing new therapeutic agents in aquaculture.