The fungal community and its interaction with the concentration of short-chain fatty acids in the faeces of Chenghua,Yorkshire and Tibetan pigs

Despite their important roles in host nutrition and metabolism, and potential to cause disease, our knowledge of the fungal community in the mammalian gut is quite limited. To date, diversity and composition of fungi in swine gut still remains unknown. Therefore, the first internal transcribed spacer of fungi in faecal samples from three breeds of pigs (10 pigs for each breed) was sequenced based on an Illumina HiSeq 2500 platform, and the relationship between the fungal community and the concentrations of main short-chain fatty acids (SCFAs) was also analysed. Results indicated that Chenghua (local, higher body fat rate), Yorkshire (foreign, higher lean meat and growth rate) and Tibetan (plateau, stronger disease resistance) pigs harboured distinct fungal community. The Basidiomycota and Ascomycota presented as the two predominant phyla, with Loreleia, Russula and Candida as the top three genera in all samples. Network analysis revealed a total of 35 correlations among different fungal genera, with 27 (77.14%) positive and 8 (22.86%) negative pairwise interactions. Canonical correspondence analysis suggested that fungi in the faeces of pigs were more correlated to the concentration of acetate and butyrate rather than propionate. Spearman’s correlation further showed that Tomentella was positively correlated to both acetate and butyrate, and Loreleia was positively correlated to propionate (P < 0.05), while Nephroma and Taiwanofungus were negatively correlated to acetate and propionate (P < 0.05). These findings expanded our knowledge on the intestinal fungi in pigs with different genotypes and phenotypes, indicating that fungi may play an indispensable role during the metabolism of host and the maintenance of intestinal health. The cross-feeding between fungi and other microorganisms may be crucial during the digestion of dietary carbohydrates and the associated physiological processes, which is worthy to be further studied.     

Distinct roles for ROCK1 and ROCK2 in the regulation of cell detachment

This study, using mouse embryonic fibroblast (MEF) cells derived from ROCK1^−/− and ROCK2^−/− mice, is designed to dissect roles for ROCK1 and ROCK2 in regulating actin cytoskeleton reorganization induced by doxorubicin, a chemotherapeutic drug. ROCK1^−/− MEFs exhibited improved actin cytoskeleton stability characterized by attenuated periphery actomyosin ring formation and preserved central stress fibers, associated with decreased myosin light chain 2 (MLC2) phosphorylation but preserved cofilin phosphorylation. These effects resulted in a significant reduction in cell shrinkage, detachment, and predetachment apoptosis. In contrast, ROCK2^−/− MEFs showed increased periphery membrane folding and impaired cell adhesion, associated with reduced phosphorylation of both MLC2 and cofilin. Treatment with inhibitor of myosin (blebbistatin), inhibitor of actin polymerization (cytochalasin D), and ROCK pan-inhibitor (Y27632) confirmed the contributions of actomyosin contraction and stress fiber instability to stress-induced actin cytoskeleton reorganization. These results support a novel concept that ROCK1 is involved in destabilizing actin cytoskeleton through regulating MLC2 phosphorylation and peripheral actomyosin contraction, whereas ROCK2 is required for stabilizing actin cytoskeleton through regulating cofilin phosphorylation. Consequently, ROCK1 and ROCK2 can be functional different in regulating stress-induced stress fiber disassembly and cell detachment.     

Effect of 25-hydroxyvitamin D3 on rotavirus replication and gene expressions of RIG-I signalling molecule in porcine rotavirus–infected IPEC-J2 cells

The study evaluated whether a 25-hydroxyvitamin D₃ (25D₃) supplementation decreases the replication of rotavirus by the retinoic acid-inducible gene I (RIG-I) signalling pathway in a porcine small intestinal epithelial cell line (IPEC-J2). The results show that IPEC-J2 cells express high baseline levels of 1α-hydroxylase (CYP27B1), which converts inactive 25D₃ to the active 1,25-dihydroxyvitamin D₃ (1,25D₃). Porcine rotavirus (PRV) infection alone resulted in a significant increase in CYP27B1 mRNA, which augmented the production of active vitamin D. Physiological concentrations of 25D₃ were found to decrease PRV replication in IPEC-J2 cells. RIG-I plays an important role in the recognition of double-stranded RNA virus by host cells. Upon recognition, RIG-I triggers a series of signalling molecules such as interferon-β (IFN-β) promoter stimulator 1 (IPS-1) leading to the expression of type I interferons (IFN-β). Active 25D₃ that was generated by PRV-infected IPEC-J2 cells led to an increased expression of toll-like receptors 3 (TLR3), RIG-I, IPS-1, IFN-β and IFN-stimulated genes 15 (ISG₁₅) with important innate immune functions. Inhibiting CYP27B1 also failed to increase RIG-I, IPS-1, IFN-β and ISG₁₅ mRNA expression. These observations suggest that 25D₃ can directly inhibit PRV in IPEC-J2 cells, which requires this active form of vitamin D. The anti-rotavirus effect of 25D₃ is mediated at least in part by RIG-I signalling pathways in IPEC-J2 cells.     

Salivary Heparanase Level Is a Potential Biomarker to Diagnose and Prognose the Malignant Salivary Gland Tumor

Background

Upregulation of heparanase has been reported in an increasing number of human cancer tissues. However, the level of salivary heparanase and its clinical significance in patients with salivary gland tumors remain unclear.

Methods

Salivary heparanase levels in patients with salivary gland tumors were detected using enzyme-linked immunosorbent assays (ELISAs) and the clinical significance was evaluated by analyzing the correlations among salivary heparanase levels, clinicopathological parameters, and clinical outcomes.

Results

The levels of salivary heparanase were significantly higher in patients with malignant salivary gland tumors than in benign tumors and normal controls (P<0.0001). High salivary heparanase levels were positively correlated with increased lymph node metastasis (P = 0.0235) and poorer tumor node metastasis stage (TNM) (P = 0.0183). Survival analyses revealed that high salivary heparanase levels were associated with worse overall survival (P = 0.0023) and disease-free survival (DFS) (P = 0.0025).

Conclusions

The study shows that salivary heparanase levels, as detected by the ELISAs, can be used to diagnose and provide an accurate prognosis for malignant salivary gland tumors. Salivary heparanase level was an independent predictor in patients with malignant salivary gland tumors.     

参与细胞增殖调控的多功能分子p21

p21是近年来发现的一类调控细胞增殖的小分子,是依赖周期素的CDK抑制因子.这些蛋白因子可结合cyclin－CDK并抑制其激酶活性从而调节细胞周期p15、p16、p27均属该类分子,他们在G₁期限制点及G₁／S检查点调控中发挥作用．进一步的研究表明,p21为p53调控,在p53介导的DNA损伤诱发的细胞周期阻断中发挥作用p21在老化细胞中高表达、细胞分化的同时表达,表明其在细胞增殖、分化及老化中发挥调节作用．     

MNT inhibits the migration of human hepatocellular carcinoma SMMC7721 cells

Muscarinic toxins (MTs) are snake venom peptides found to selectively target specific subtypes of G-protein-coupled receptors. In here, we have attached a glycosylphosphatidylinositol (GPI) tail to three different toxin molecules and evaluated their receptor-blocking effects in a heterologous expression system. MT7-GPI remained anchored to the cell surface and selectively inhibited M(1) muscarinic receptor signaling expressed in the same cell. To further demonstrate the utility of the GPI tail, we generated MT3- and MTα-like gene sequences and fused these to the signal sequence for GPI attachment. Functional assessment of these membrane-anchored toxins on coexpressed target receptors indicated a prominent antagonistic effect. In ligand binding experiments the GPI-anchored toxins were found to exhibit similar selection profiles among receptor subtypes as the soluble toxins. The results indicate that GPI attachment of MTs and related receptor toxins could be used to assess the role of receptor subtypes in specific organs or even cells in vivo by transgenic approaches.