Benefits of Biochar for Improving Ion Contents,Cell Membrane Permeability,Leaf Water Status and Yield of Rice Under Saline–Sodic Paddy Field Condition

Journal of Plant Growth Regulation - Saline–sodic is one of the major conditions threatening crop production. Biochar application could alleviate the adverse impacts of saline–sodic...     

Abundance and Diversity of Sulfur-Oxidizing Bacteria along a Salinity Gradient in Four Qinghai-Tibetan Lakes,China

Sulfur-oxidizing bacteria (SOB) play important roles in the sulfur cycle and are widespread in a number of environments, but their occurrence and relationship to geochemical conditions in (hyper)saline lakes are still poorly understood. In this study, the abundance and diversity of SOB populations were investigated in four Qinghai-Tibetan lakes (Erhai Lake, Gahai Lake 1, Gahai Lake 2 and Xiaochaidan Lake) by using quantitative polymerase chain reaction (qPCR) and soxB gene- (encoding sulfate thiohydrolase) based phylogenectic analyses. qPCR analyses showed that in the studied lakes, the total bacterial 16S rRNA and soxB gene abundances in the sediments were distinctly higher than in the overlying waters. The 16S rRNA gene abundance in the waters ranged 5.27 × 10⁶–6.09 × 10⁸ copies per mL and 7.39 × 10¹⁰–2.9 × 10¹¹ copies per gram sediment. The soxB gene abundance in the waters ranged from 1.88 × 10⁴ to 5.21 × 10⁵ per mL and 4.73 × 10⁶–2.65 × 10⁷ copies per gram sediment. The soxB gene in the waters of the two hypersaline lakes (Gahai Lake 2 and Xiaochaidan Lake) was more abundant (2.97 × 10⁵ and 5.21 × 10⁵ copies per mL) than that in the two low-salinity lakes (1.88 × 10⁴ and 3.36 × 10⁴ copies per mL). Phylogenetic analysis showed that Alpha- and Betaproteobacteria were dominant SOB in the investigated lakes, and the composition of proteobacterial subgroups varied with salinity: in freshwater Erhai Lake and low-salinity Gahai Lake 1, the SOB populations were dominated by the Betaproteobacteria, whereas in hypersaline Lake Gahai 2 and Xiaochaidan Lake, the SOB populations were dominated by Alphaproteobacteria. Overall, salinity played a key role in controlling the diversity and distribution of SOB populations in the investigated Qinghai-Tibetan lakes.     

MicroRNAs and their role in viral infection

Recently,a class of about 22 nucleotides (nt)small RNA has been discovered in many eukaryotes,termed microRNAs (miRNAs),which have a variety of functions.Many recent findings have demonstrated that viruses can also encode their own miRNAs.Meanwhile,other findings reveal a relationship between host miRNA and viral infection.These findings suggest a tight relationship between host and viral infection via miRNA pathway.This article introduces the miRNAs encoded by viruses and reviews the advances of the interaction of the mammalian host miRNAs and viral infection.     

High‐density interspecific genetic linkage mapping provides insights into genomic incompatibility between channel catfish and blue catfish

Catfish is the leading aquaculture species in the United States. The interspecific hybrid catfish produced by mating female channel catfish with male blue catfish outperform both of their parent species in a number of traits. However, mass production of the hybrids has been difficult because of reproductive isolation. Investigations of genome structure and organization of the hybrids provide insights into the genetic basis for maintenance of species divergence in the face of gene flow, thereby helping develop strategies for introgression and efficient production of the hybrids for aquaculture. In this study, we constructed a high‐density genetic linkage map using the hybrid catfish system with the catfish 250K SNP array. A total of 26 238 SNPs were mapped to 29 linkage groups, with 12 776 unique marker positions. The linkage map spans approximately 3240 cM with an average intermarker distance of 0.25 cM. A fraction of markers (986 of 12 776) exhibited significant deviation from the expected Mendelian ratio of segregation, and they were clustered in major genomic blocks across 15 LGs, most notably LG9 and LG15. The distorted markers exhibited significant bias for maternal alleles among the backcross progenies, suggesting strong selection against the blue catfish alleles. The clustering of distorted markers within genomic blocks should lend insights into speciation as marked by incompatibilities between the two species. Such findings should also have profound implications for understanding the genomic evolution of closely related species as well as the introgression of hybrid production programs in aquaculture.     

Responses of groundwater vulnerability to groundwater extraction reduction in the Hun River Basin,northeastern China

Intensive groundwater extraction causes many environmental problems globally. Reducing groundwater extraction is a primary method for alleviating these problems. However, this reduction may create new pollution issues because of an increase in groundwater vulnerability. A case study was done using the DRAOTIC evaluation method (an improved DRASTIC method for organic pollutant in aquifer vulnerability; soil (S factor) has been updated by organic matter (O factor) in the method) for the Hun River Basin, northeastern China, where groundwater intensive extraction had caused serious environmental and hydrogeological problems. The assessment results show that moderate vulnerability level is the main vulnerability level in the Hun River Basin; high vulnerability level and low vulnerability level categories occupy a smaller area; while very high and very low vulnerability categories occupy the smallest area. By combining the predicted groundwater level distribution and DRAOTIC model, the responses of groundwater vulnerability to different groundwater extraction reductions could be studied. The results show that groundwater vulnerability levels increased as groundwater extraction was reduced; this is because the rising groundwater levels make it easier for pollution coming from the surface to reach the aquifer. The more the reduction in groundwater extraction, the greater the increase in the area with higher vulnerability levels, and the greater the increase in pollution risk.     

Fluid shear stress regulates osteoblast proliferation and apoptosis via the lncRNA TUG1/miR-34a/FGFR1 axis

LncRNAs and microRNAs play critical roles in osteoblast differentiation and bone formation. However, their exact roles in osteoblasts under fluid shear stress (FSS) and the possible mechanisms remain unclear. The aim of this study was to explore whether and how miR-34a regulates osteoblast proliferation and apoptosis under FSS. In this study, FSS down-regulated miR-34a levels of MC3T3-E1 cells. MiR-34a up-regulation attenuated FSS-induced promotion of proliferation and suppression of apoptosis. Luciferase reporter assay revealed that miR-34a directly targeted FGFR1. Moreover, miR-34a regulated osteoblast proliferation and apoptosis via FGFR1. Further, we validated that lncRNA TUG1 acted as a competing endogenous RNA (ceRNA) to interact with miR-34a and up-regulate FGFR1 protein expression. Furthermore, lncRNA TUG1 could promote proliferation and inhibit apoptosis. Taken together, our study revealed the key role of the lncRNA TUG1/miR-34a/FGFR1 axis in FSS-regulated osteoblast proliferation and apoptosis and may provide potential therapeutic targets for osteoporosis.     

Optimizing foliar allocation of limiting nutrients and fast‐slow economic strategies drive forest succession along a glacier retreating chronosequence in the eastern Tibetan Plateau

Plant and Soil - Nitrogen (N) and phosphorus (P) availabilities limit plant productivity, especially in primary succession; however, our understanding of species-specific strategies regarding their...     

Structural and computational studies of the maleate isomerase from Pseudomonas putida S16 reveal a breathing motion wrapping the substrate inside

Nicotine is an environmental toxicant in tobacco waste, imposing a serious hazard for human health. Some bacteria including Pseudomonas spp. strains are able to metabolize nicotine to non‐toxic compounds. The pyrrolidine pathway of nicotine degradation in Pseudomonas putida S16 has recently been revealed. The maleate isomerase (Pp‐Iso) catalyses the last step in nicotine degradation of P. putida S16, the cis‐trans isomerization of maleate to fumarate. In this study, we determined the crystal structures of both wild type isomerase by itself and its C200A point mutant in complex with its substrate maleate, to resolutions of 2.95 Å and 2.10 Å respectively. Our structures reveal that Asn17 and Asn169 play critical roles in recognizing the maleate by site‐directed mutants' analysis. Surprisingly, our structure shows that the maleate is completely wrapped inside the isomerase. Examination of the structure prompted us to hypothesize that the β2‐α2 loop and the β6‐α7 loop have a breathing motion that regulates substrate/solvent entry and product departure. Our results of molecular dynamics simulation and enzymatic activity assay are fully consistent with this hypothesis. The isomerase probably uses this breathing motion to prevent the solvent from entering the active site and prohibit unproductive side reactions from happening.     

Microbial Products Induce Claudin-2 to Compromise Gut Epithelial Barrier Function

The epithelial barrier dysfunction is an important pathogenic feature in a number of diseases. The underlying mechanism is to be further investigated. The present study aims to investigate the role of tight junction protein claudin-2 (Cldn2) in the compromising epithelial barrier function. In this study, the expression of Cldn2 in the epithelial layer of mice and patients with food allergy was observed by immunohistochemistry. The induction of Cldn2 was carried out with a cell culture model. The Cldn2-facilitated antigen internalization was observed by confocal microscopy. The epithelial barrier function in the gut epithelial monolayer was assessed by recording the transepithelial resistance and assessing the permeability to a macromolecular tracer. The results showed that the positive immune staining of Cldn2 was observed in the epithelial layer of the small intestine that was weakly stained in naïve control mice, and strongly stained in sensitized mice as well as patients with food allergy. Exposure to cholera toxin or Staphylococcal enterotoxin B induced the expression of Cldn2 in HT-29 or T84 cells. Cldn2 could bind protein antigen to form complexes to facilitate the antigen transport across the epithelial barrier. Blocking Cldn2 prevented the allergen-related hypersensitivity the intestine. We conclude that the tight junction protein Cldn2 is involved in the epithelial barrier dysfunction.