Generation and characterization of Megf6 null and Cre knock‐in alleles

Megf6, a member of MEGF (multiple EGF‐like domains) protein family, is a conserved high molecular weight protein with 30 EGF‐like domains. Although many members of the MEGF protein family are essential for embryonic development and homeostasis, the role of Megf6 in development and physiology is still unknown. Here, we generated Megf6‐deficient mice using CRISPR‐Cas9 technique and showed that Megf6 is dispensable for embryonic development. We also constructed the Megf6^Cre allele to study Megf6‐expressing cell lineages. Our results showed that Megf6‐expressing cells contribute to the periotic mesenchyme and its derivatives, skin epidermis, certain cells in brain and ribs. Therefore, the Megf6^Cre allele can be a useful tool for conditional deletion in these tissues, in particular for periotic mesenchyme deletion.     

Effect of Bacillus mesonae H20-5 Treatment on Rhizospheric Bacterial Community of Tomato Plants under Salinity Stress

Plant growth-promoting bacteria improve plant growth under abiotic stress conditions. However, their effects on microbial succession in the rhizosphere are poorly understood. In this study, the inoculants of Bacillus mesonae strain H20-5 were administered to tomato plants grown in soils with different salinity levels (EC of 2, 4, and 6 dS/m). The bacterial communities in the bulk and rhizosphere soils were examined 14 days after H20-5 treatment using Illumina MiSeq sequencing of the bacterial 16S rRNA gene. Although the abundance of H20-5 rapidly decreased in the bulk and rhizosphere soils, a shift in the bacterial community was observed following H20-5 treatment. The variation in bacterial communities due to H20-5 treatment was higher in the rhizosphere than in the bulk soils. Additionally, the bacterial species richness and diversity were greater in the H20-5 treated rhizosphere than in the control. The composition and structure of the bacterial communities varied with soil salinity levels, and those in the H20-5 treated rhizosphere soil were clustered. The members of Actinobacteria genera, including Kineosporia, Virgisporangium, Actinoplanes, Gaiella, Blastococcus, and Solirubrobacter, were enriched in the H20-5 treated rhizosphere soils. The microbial co-occurrence network of the bacterial community in the H20-5 treated rhizosphere soils had more modules and keystone taxa compared to the control. These findings revealed that the strain H20-5 induced systemic tolerance in tomato plants and influenced the diversity, composition, structure, and network of bacterial communities. The bacterial community in the H20-5 treated rhizosphere soils also appeared to be relatively stable to soil salinity changes.     

Characterization of a novel thermo-stable lipase from endophyte <Emphasis Type="Italic">Pseudomonas putida</Emphasis> in <Emphasis Type="Italic">Pistacia chinensis</Emphasis> Bunge

A novel lipolytic enzyme-producing endophytic strain PC2 was successfully isolated from the seeds of an ideal bioenergy plant Pistacia chinensis Bunge. Based on the analysis of morphology and 16S rRNA sequence, bacterial strain PC2 was identified as a subspecies of Pseudomonas putida, therefore named as P. putida PC2. Whole-genome sequencing showed PC2 contained a 1224-nucleotide lipase gene (named lip-PC2) predicted to encode a 407-amino-acid protein. Purified lipases from both the original PC2 strain and heterologously expressed Escherichia coli were nearly 50 kD with specific activity of 9.48 U/mL. LIP-PC2 displayed the maximal activity at 50°C or pH 8.0, and maintained above 80% relative activity in the range of from 40 to 60°C or pH in the range of from 6.0 to 8.0, indicating thermostable and alkaline properties. Enzyme activity was enhanced by Mg²⁺, Na⁺ and Mn²⁺, but strongly inhibited by Cu²⁺, Zn²⁺ Co²⁺, EDTA as well as organic solvents and surfactants. Additionally, the analysis of amino acid sequence and structure indicated that LIP-PC2 was a novel member belonging to family I.3 of bacterial lipolytic enzymes and its catalytic triad was consisted of Ser-200, Asp-342 and His-374.     

Reduction of chronic graft injury with a new HTK-based preservation solution in a murine heart transplantation model

Objective

Aim of this study was to evaluate a new histidine-tryptophan-ketoglutarate (HTK)-based preservation solution on chronic isograft injury in comparison to traditional HTK solution.

Methods

Hearts of C57BL/6J (H-2b) mice were stored for 15 h in 0–4 °C cold preservation solution and then transplanted heterotopically into C57BL/6J (H-2b) mice. Three groups were evaluated: HTK, the base solution of a new preservation solution and hearts without cold ischemia (control). Time to restoration of heartbeat was measured (re-beating time). Strength of the heartbeat was palpated daily and scored on a 4-level scale (palpation score). Animals were sacrificed after 60 days of observation (24 h for TGF-β expression). The transplanted hearts were evaluated histologically for myocardial damage, vasculopathy and interstitial fibrosis. TGF-β expression was assessed immunohistologically. All investigators were blinded to the groups. ANOVA and LSD post hoc test were used for statistical analysis.

Results

The re-beating time was significantly shorter in hearts stored in the new solution (10.3 ± 2.6 min vs. HTK 14.2 ± 4.1 min; p < 0.05). The palpation score was significantly higher in hearts stored in the new solution (2.3 ± 0.4 vs. HTK 1.6 ± 0.5; p < 0.01). Hearts stored in the new solution showed a lower myocardial injury score (1.8 ± 0.2 vs. HTK 2.2 ± 0.7), less interstitial fibrosis (4.8 ± 1.9% vs. HTK 8.5 ± 3.8%, p < 0.05), less vasculopathy (14.7 ± 6.9% vs. 22.0 ± 23.2%; p = 0.06) and lower TGF-β1-expression (6.6 ± 1.4% vs. HTK 12.0 ± 4.6%).

Conclusion

The new HTK-based solution reduces the chronic isograft injury. This protective effect is likely achieved through several modifications and supplements into the new solution like N-acetyl-l-histidine, glycine, alanine, arginine and sucrose.     

水稻幼芽细胞生物膜上的赤霉素结合蛋白的结合特性

在水稻 (Oryza sativa)幼芽中存在膜结合的赤霉素结合蛋白 ,其与 GA3 结合的平衡解离常数(Kd)为 6.5× 1 0 -8mol/ L,总浓度为 0 .3 pmol· mg-1 蛋白质。结合蛋白与 GA3 结合活力在 0℃时比 2 5℃时高 1 4 0 %。它与 GA3 结合的最适 p H为 5。 GA3 与此结合蛋白的结合量随反应时间延长而增加 ,1 h达最大值 ,以后又逐渐下降。 IAA、ABA可与 GA3 竞争赤霉素结合蛋白。     

Comparative analysis of complete chloroplast genome sequences of two subtropical trees, <Emphasis Type="Italic">Phoebe sheareri</Emphasis> and <Emphasis Type="Italic">Phoebe omeiensis</Emphasis> (Lauraceae)

Phoebe is an economically important genus from the family Lauraceae. It is widely distributed in tropical and subtropical Asia, but systematics of the genus is unclear, and currently there is no species-level phylogeny. Here, we determined the complete chloroplast genome sequences of two species with long-range PCR and next genome sequencing technologies, and identified mutation sites and highly variable regions. These highly variable sites were used to reconstruct the phylogeny. The plastomes of Phoebe sheareri and P. omeiensis were 152, 876, and 152, 855 bp, respectively. Comparative genomic analysis indicated that there are 222 mutation sites including 146 substitutions, 73 indels, and 3 microinversions in both plastomes. Fifty-six single-nucleotide changes were identified in gene-coding regions, and 45 microsatellite sites were found for use in species identification. Fourteen divergence hotspots of 38 variable regions were located. Phylogeny was reconstructed using a Bayesian and maximum likelihood approach for 12 Phoebe species and other five related Lauraceae based on 15 of the highly variable regions including accD-psaI, atpB-rbcL, ndhC-trnV, ndhF-rpl32, petA-psbJ, psaA, psbA-trnH, rbcL, rps8-rpl14, rps16-trnQ, rpl32-trnL, trnC-petN, trnL-trnF, trnS-trnG, and ycf1 indicated that variability in the chloroplast regions proposed as variable is enough to detect divergence events among 12 taxa of Phoebe, and that maybe also useful to help to elucidate further relationships among other taxa of the genus.     

Plasma metabonomics as a novel diagnostic approach for major depressive disorder

Major depressive disorder (MDD) is a socially detrimental psychiatric disorder, contributing to increased healthcare expenditures and suicide rates. However, no empirical laboratory-based tests are available to support the diagnosis of MDD. In this study, a NMR-based plasma metabonomic method for the diagnosis of MDD was tested. Proton nuclear magnetic resonance ((1)H NMR) spectra of plasma sampled from first-episode drug-na??ve depressed patients (n = 58) and healthy controls (n = 42) were recorded and analyzed by orthogonal partial least-squares discriminant analysis (OPLS-DA). The OPLS-DA score plots of the spectra demonstrated that the depressed patient group was significantly distinguishable from the healthy control group. Moreover, the method accurately diagnosed blinded samples (n = 26) in an independent replication cohort with a sensitivity and specificity of 92.8% and 83.3%, respectively. Taken together, NMR-based plasma metabonomics may offer an accurate empirical laboratory-based method applicable to the diagnosis of MDD.