Lower Abundance of Ammonia-Oxidizing Archaea Than Ammonia-Oxidizing Bacteria Detected in the Subsurface Sediments of the Northern South China Sea

Diversity and abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in samples of the northern South China Sea subsurface sediment were assessed by analyzing the amoA gene sequences retrieved from the samples. The microbial diversity was assessed using rarefaction and phylogenetic analyses. The deep-sea subsurface sediments harbored diverse and distinct AOA and AOB communities, but the abundance of AOA was lower than that of AOB, consistent with many other studies about bacteria and archaea in subsurface sediments. Diversity of AOA shown in the OTUs and Shannon index was correlated with the concentration of nitrite in the Pearson analysis, but no obvious relationships between the diversity or abundance of AOB and the physicochemical parameters could be identified in the present study, indicating the concentration of ammonium may not be an important factor to determine the diversity and abundance of ammonia-oxidizing prokaryotes in the subsurface sediments. Additionally, Nitrosomonas-like AOB was found to be dominant in subsurface sediments of the northern South China Sea showing a different adaption strategy comparing with some Nitrosospira-like AOB lineages. Concentration of nitrite was correlated with diversity of AOA, but no correlations between diversity and abundance of AOB and the physicochemical parameters were established in the study. Supplementary materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental files.     

Store-Operated Ca2+ Channels Blockers Inhibit Lipopolysaccharide Induced Astrocyte Activation

The destruction of calcium homeostasis is an important factor leading to neurological diseases. Store-operated Ca²⁺ (SOC) channels are essential for Ca²⁺ homeostasis in many cell types. However, whether SOC channels are involved in astrocyte activation induced by lipopolysaccharide (LPS) still remains unknown. In this study, we used LPS as an exogenous stimulation to investigate the role of SOC channels in astrocyte activation. Using calcium imaging technology, we first found that SOC channels blockers, 1-[h-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole (SKF-96365) and 2-aminoethyldiphenyl borate (2-APB), inhibited LPS induced [Ca²⁺]_i increase, which prompted us to speculate that SOC channels may be involved in LPS induced astrocyte activation. Further experiments confirmed our speculation shown as SOC channels blockers inhibited LPS induced astrocyte activation characterized as cell proliferation by MTS and BrdU assay, raise in glial fibrillary acidic protein expression by immunofluorescence and Western Blot and secretion of interleukin 6 (IL-6) and interleukin 1β (IL-1β) by ELISA. So, our studies showed that SOC channels are involved in LPS-induced astrocyte activation.     

Isolation and characterization of fatty acid methyl ester (FAME)‐producing Streptomyces sp. S161 from sheep (Ovis aries) faeces

An actinomycete producing oil‐like mixtures was isolated and characterized. The strain was isolated from sheep faeces and identified as Streptomyces sp. S161 based on 16S rRNA gene sequence analysis. The strain showed cellulase and xylanase activities. The ¹H nuclear magnetic resonance (NMR) spectra of the mixtures showed that the mixtures were composed of fatty acid methyl esters (52·5), triglycerides (13·7) and monoglycerides (9·1) (mol.%). Based on the gas chromatography–mass spectrometry (GC‐MS) analysis, the fatty acid methyl esters were mainly composed of C14‐C16 long‐chain fatty acids. The results indicated that Streptomyces sp. S161 could produce fatty acid methyl esters (FAME) directly from starch. To our knowledge, this is the first isolated strain that can produce biodiesel (FAME) directly from starch.

Significance and Impact of the Study

Nowadays, production of biodiesel is based on plant oils, animal fats, algal oils and microbial oils. Lipid mostly consists of triacylglycerols (TAG), and conversion of these lipids into fatty acid short‐chain alcohol esters (methanol or ethanol) is the final step in biodiesel production. In this study, an oil‐producing Streptomyces strain was isolated from sheep faeces. The oil was composed of C₁₄‐C₁₆ long‐chain fatty acid methyl esters, triglycerides and monoglycerides. This is the first isolated strain‐producing biodiesel (FAME) directly from starch. Due to showing cellulase and xylanase activities, the strain would be helpful for converting renewable lignocellulose into biodiesel directly.     

Temporal-Spatial Expressions of Spy1 in Rat Sciatic Nerve After Crush

As a novel cell cycle protein, Spy1 enhances cell proliferation, promotes the G1/S transition as well as inhibits apoptosis in response to UV irradiation. Spy1 levels are tightly regulated during mammary development, and overexpression of Spy1 accelerates tumorigenesis in vivo. But little is known about the role of Spy1 in the pathological process of damage and regeneration of the peripheral nervous system. Here we established a rat sciatic nerve crush (SNC) model to examine the spatiotemporal expression of Spy1. Spy1 expression was elevated gradually after sciatic nerve crush and peaked at day 3. The alteration was due to the increased expression of Spy1 in axons and Schwann cells after SNC. Spy1 expression correlated closely with Schwann cells proliferation in sciatic nerve post injury. Furthermore, Spy1 largely localized in axons in the crushed segment, but rarely co-localized with GAP43. These findings suggested that Spy1 participated in the pathological process response to sciatic nerve injury and may be associated with Schwann cells proliferation and axons regeneration.     

Molecular cloning, tissue expression and SNP analysis in the goat nerve growth factor gene

In this study, we cloned the full coding region of NGF gene from the caprine ovary. Result showed the caprine NGF cDNA (GenBank Accession No. JQ308184) contained a 726 bp open reading frame encoding a protein with 241 amino acid residues. Bioinformatic analysis indicated that caprine NGF amino acid sequence was 83–99 % identical to that of mouse, pig, dog, human and bovine. It was predicted that caprine NGF contained nine serine phosphorylation loci, four threonine phosphorylation loci and nine specific PKC phosphorylation loci. The NGF mRNA expression pattern showed that NGF gene was expressed highly in ovary. This work provided an important experimental basis for further research on the function of NGF in goat. A single nucleotide polymorphism (A705G) in the coding region of NGF gene was detected by PCR–RFLP and DNA sequencing in 630 goats of three breeds. The frequencies of G allele were 0.52–0.61, and frequencies of A allele were 0.48–0.39 for SN, GZ and BG breeds, respectively. The does with GG genotype had higher litter size than those with GA and AA genotypes (P < 0.05). Hence, the biochemical and physiological functions, together with the results obtained in our investigation, suggest that the NGF gene could serve as a genetic marker for litter size in goat breeding.     

Spironolactone inhibits apoptosis in rat mesangial cells under hyperglycaemic conditions via the Wnt signalling pathway

Mesangial cells (MCs) play a crucial role in maintaining structure and function of glomerular tufts, providing structural support for capillary loops and modulating glomerular filtration by their contractility. MCs apoptosis occurs in experimental diabetic nephropathy, and this correlates with worsening albuminuria. Accumulating evidence suggests that mineralocorticoid receptor (MR) blockade effectively reduces proteinuria in diabetic nephropathy; however, it is rarely known whether spironolactone (SPI), a nonspecific MR antagonist, inhibits apoptosis in MCs under hyperglycaemic conditions. The objectives of this study are to determine the relationship between SPI and apoptosis, and investigate the cell signalling pathway by which SPI inhibits apoptosis. Rat MCs were treated with 30 mM d-glucose and 10^?8, 10^?7 or 10^?6 M aldosterone (ALD) for 24 h. In some experiments, MCs were pretreated with 10^?7 M SPI or 10 mM LiCl for 1 h. Apoptosis was evaluated by cell nucleus staining and flow cytometric analyses, and caspase-3 activity was assayed. Gene and protein expression were quantified using quantitative real-time PCR and Western blotting, respectively. SPI directly inhibited high glucose and ALD-induced MCs apoptosis in a caspase-dependent manner. Importantly, SPI inhibited MCs apoptosis via the Wnt signalling pathway. SPI promoted activation of the Wnt signalling pathway in MCs, leading to upregulation of Wnt4 and Wnt5a mRNA expression, decreased GSK-3β protein expression and increased β-catenin protein expression. As a conclusion, this study suggests that SPI may inhibit apoptosis in MCs during hyperglycaemic conditions via the Wnt signalling pathway. Blockade of the ALD system may represent a novel therapeutic strategy to prevent MCs injury under hyperglycaemic conditions.