Interactions between Biotite and the Mineral-Weathering Bacterium Pseudomonas azotoformans F77.

In this study, the mineral-weathering bacterium Pseudomonas azotoformans F77, which was isolated from the soil of a debris flow area, was evaluated for its weathering activity under direct contact with biotite or without contact. Then, biotite-weathering behaviors of strain F77, mutants that had been created by deleting the gcd and adh genes (which are involved in gluconic acid metabolism and pilus formation, respectively), and the double mutant F77ΔgcdΔadh were compared. The relative gene expression levels of F77 and its mutants F77Δgcd and F77Δadh were also analyzed in the presence of biotite. Direct contact with biotite increased Fe and Al release from the mineral in the presence of F77. All strains had similar abilities to release Fe and Al from the mineral except for F77Δgcd and F77Δadh Mobilized Fe and Al concentrations were decreased by up to 72, 26, and 87% in the presence of F77Δgcd, F77Δadh, and F77ΔgcdΔadh, respectively, compared to levels observed in the presence of F77 during the mineral-weathering process. Gluconic acid production was decreased for F77Δgcd and F77ΔgcdΔadh, while decreased cell attachment on the mineral surface was observed for F77Δadh, compared to findings for F77. The F77 genes involved in pilus formation and gluconic acid metabolism showed increased expression levels in the presence of biotite. The results of this study showed important roles for the genes involved in gluconic acid metabolism and pilus formation in mineral weathering by F77 and demonstrated the distinctive effect of these genes on mineral weathering by F77.IMPORTANCE Bacteria play important roles in mineral weathering and soil formation, although the molecular mechanisms underlying the interactions between bacteria and silicate minerals are poorly understood. In this study, the interactions between biotite and the highly effective mineral-weathering bacterium P. azotoformans F77 were characterized. Our results showed that the genes involved in gluconic acid metabolism and pilus formation play important roles in mineral weathering by F77. The presence of biotite could promote the expression of these genes in F77, and a distinctive effect of these genes on mineral weathering by F77 was observed in this study. Our results provide new knowledge and promote better understanding regarding the interaction between silicate minerals and mineral-weathering bacteria, as well as the molecular mechanisms involved in these processes.

The Rice Receptor-Like Kinases DWARF AND RUNTISH SPIKELET1 and 2 Repress Cell Death and Affect Sugar Utilization during Reproductive Development.

Cell-to-cell communication precisely controls the creation of new organs during reproductive growth. However, the sensor molecules that mediate developmental signals in monocot plants are poorly understood. Here, we report that DWARF AND RUNTISH SPIKELET1 (DRUS1) and DRUS2, two closely related receptor-like kinases (RLKs), redundantly control reproductive growth and development in rice (Oryza sativa). A drus1-1 drus2 double knockout mutant, but not either single mutant, showed extreme dwarfism and barren inflorescences that harbored sterile spikelets. The gibberellin pathway was not impaired in this mutant. A phenotypic comparison of mutants expressing different amounts of DRUS1 and 2 revealed that reproductive growth requires a threshold level of DRUS1/2 proteins. DRUS1 and 2 maintain cell viability by repressing protease-mediated cell degradation and likely by affecting sugar utilization or conversion. In the later stages of anther development, survival of the endothecium requires DRUS1/2, which may stimulate expression of the UDP-glucose pyrophosphorylase gene UGP2 and starch biosynthesis in pollen. Unlike their Arabidopsis thaliana ortholog FERONIA, DRUS1 and 2 mediate a fundamental signaling process that is essential for cell survival and represents a novel biological function for the CrRLK1L RLK subfamily.

Association of plasma free fatty acids levels with the presence and severity of coronary and carotid atherosclerotic plaque in patients with type 2 diabetes mellitus.

BACKGROUND: Previous studies have suggested that patients with diabetes mellitus (DM) have higher prevalence of atherosclerotic cardiovascular disease (ASCVD), and plasma levels of free fatty acids (FFAs) are a useful marker for predicting ASCVD. We hypothesized that FFAs could predict both coronary and carotid lesions in an individual with type 2 DM (T2DM). The present study, hence, was to investigate the relation of plasma FFA level to the presence and severity of coronary and carotid atherosclerosis in patients with T2DM. METHODS: Three hundred and two consecutive individuals with T2DM who have received carotid ultrasonography and coronary angiography due to chest pain were enrolled in this study. Plasma FFAs were measured using an automatic biochemistry analyzer. Coronary and carotid severity was evaluated by Gensini score and Crouse score respectively. Subsequently, the relation of FFA levels to the presence and severity of coronary artery disease (CAD) and carotid atherosclerotic plaque (CAP) in whole individuals were also assessed. RESULTS: Increased plasma FFA levels were found in the groups either CAD or CAP compared to those without. Patients with higher level of FFAs had a higher CAD (89.9%) and elevated prevalence of CAP (69.7%). And also, patients with higher level of FFAs had a higher Gensini and Crouse scores. Multivariate regression analysis showed that FFA levels were independently associated with the presence of CAD and CAP (OR = 1.83, 95%CI: 1.27-2.65, P = 0.001; OR = 1.62, 95%CI: 1.22-2.14, P = 0.001, respectively). The area under the curve (AUC) was 0.68 and 0.65 for predicting the presence of CAD and CAP in patients with DM respectively. CONCLUSIONS: The present study firstly indicated that elevated FFA levels appeared associated with both the presence and severity of CAD and CAP in patients with T2DM, suggesting that plasma FFA levels may be a useful biomarker for improving management of patients with T2DM.

Resveratrol attenuates skeletal muscle atrophy induced by chronic kidney disease via MuRF1 signaling pathway.

Skeletal muscle atrophy is an important clinical characteristic of chronic kidney disease (CKD); however, at present, the therapeutic approaches to muscle atrophy induced by CKD are still at an early stage of development. Resveratrol is used to attenuate muscle atrophy in other experimental models, but the effects on a CKD model are largely unknown. Here, we showed that resveratrol prevented an increase in MuRF1 expression and attenuated muscle atrophy in vivo model of CKD. We also found that phosphorylation of NF-κB was inhibited at the same time. Dexamethasone-induced MuRF1 upregulation was significantly attenuated in C2C12 myotubes by resveratrol in vitro, but this effect on C2C12 myotubes was abrogated by a knockdown of NF-κB, suggesting that the beneficial effect of resveratrol was NF-κB dependent. Our findings provide novel information about the ability of resveratrol to prevent or treat muscle atrophy induced by CKD.

Identification of circulating lncRNA in chronic kidney disease based on bioinformatics analysis.

Chronic kidney disease (CKD) is a high mortality disease and generally remains asymptomatic in the early stages. Long non-coding RNA (lncRNA) is defined as a non-protein-coding transcript more than 200 nucleotides which participate in numerous biological processes and have been identified as novel diagnostic markers for many diseases. Detection of circulating lncRNAs is a rapidly evolving, new area of molecular diagnosis. The purpose of our research was to identify circulating lncRNA expression profiles and possible molecular mechanisms involved in CKD. Blood samples were obtained from patients with CKD and healthy volunteers, and high-throughput sequencing was performed to identify differentially expressed (DE) lncRNAs and mRNAs. DE lncRNAs and mRNAs in peripheral blood mononuclear cells (PBMCs) were confirmed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) to ensure the reliability and validity of RNA-seq data. Bioinformatics analysis was used to obtain biological functions and key pathways related to the pathogenesis of CKD. The interaction and co-expression functional networks for DE lncRNAs and mRNAs were also constructed. Our data showed that of the 425 DE lncRNAs detected, 196 lncRNAs were upregulated, while that of 229 lncRNAs were downregulated. A total of 433 DE mRNAs were identified in patients with CKD compared to healthy individuals. GO analysis revealed that DE lncRNAs were highly correlated with binding and pathway regulation. KEGG analysis suggested that DE lncRNAs were obviously enriched in regulatory pathways, such as antigen processing and presentation. We successfully constructed a potential DE lncRNA-mRNA co-expression network and analyzed the target genes of DE lncRNAs to predict cis- and trans-regulation in CKD. 100 lncRNAs that corresponded to 14 transcription factors (TFs) were identified in the TF-lncRNA binary network. Our findings on the lncRNA expression profiles and functional networks may help to interpret the possible molecular mechanisms implied in the pathogenesis of CKD; the results demonstrated that lncRNAs could potentially to be used as diagnostic biomarkers in CKD.

[Effects of low-protein diet plus alpha-keto acid on micro-inflammation and the relationship between micro-inflammation and nutritional status in patients performing continuous ambulatory peritoneal dialysis: a randomized controlled trial].

OBJECTIVE: To investigate the effects of the combination of alpha-keto acid and low-protein diet on the levels of serum cytokines in patients performing continuous ambulatory peritoneal dialysis (CAPD) and to explore the relationship between inflammation and malnutrition in CAPD patients. METHODS: Eighty-nine CAPD patients were randomized into three groups, and 78 cases completed a one-year follow-up and with complete data. There were 31 cases in low-protein diet plus alpha-keto acid group, 26 cases in low-protein diet group and 21 cases in routine-protein diet group. The levels of serum albumin (Alb), prealbumin (PA), retinol-binding protein (RBP), transferrin (TRF), cholesterol (TC), triglycerides (TG), leptin, and triceps skinfold thickness (TSF), mid-arm muscle circumference (MAMC), body mass index (BMI) were measured. The changes of serum interleukin-1alpha (IL-1alpha), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein (CRP) were also detected. RESULTS: Compared with low-protein diet group, serum levels of PA, RBP and TRF were significantly increased both in low-protein diet plus alpha-keto acid and routine-protein diet groups ( P<0.01), however, there was no significant difference in the levels of PA, RBP and TRF between low-protein diet plus alpha-keto acid group and routine-protein diet group. There was an increased tendency in the content of Alb, TC, TG, BMI, TSF and MAMC, but there were no significant differences. The plasma levels of IL-1alpha, IL-6 and TNF-alpha in low-protein diet plus alpha-keto acid group were decreased as compared with the routine-protein diet group, but there were no significant differences. The plasma level of CRP in low-protein diet plus alpha-keto acid group was lower than that in the routine-protein diet group ( P<0.01). CONCLUSION: The combination of alpha-keto acid and low-protein diet can ameliorate malnutrition and micro-inflammation in CAPD patients.

Effects of mineralocorticoid receptor antagonists on the progression of diabetic nephropathy.

AIMS/INTRODUCTION: We aimed to evaluate the potential benefits and adverse effects of adding a mineralocorticoid receptor antagonist (MRA) to angiotensin-converting enzyme inhibitors (ACEI) and/or angiotensin receptor blockers (ARB), as standard treatment in patients with diabetic nephropathy. MATERIALS AND METHODS: We scanned the Embase, PubMed and Cochrane Central Register of Controlled Trials databases for human clinical trials published in English until June 2016, evaluating renal outcomes in patients with diabetic nephropathy. RESULTS: A total of 18 randomized controlled trials involving 1,786 patients were included. Compared with ACEI/ARB alone, co-administration of MRA and ACEI/ARB significantly reduced urinary albumin excretion and the urinary albumin-creatinine ratio (mean difference -69.38, 95% confidence intervals -103.53 to -35.22, P < 0.0001; mean difference -215.74, 95% confidence intervals -409.22 to -22.26, P = 0.03, respectively). A decrease of blood pressure was also found in the co-administration of MRA and ACEI/ARB groups. However, we did not observe any improvement in the glomerular filtration rate. There was a significant increase in the risk of hyperkalemia on the addition of MRA to ACEI/ARB treatment (relative risk 3.74, 95% confidence intervals 2.30-6.09, P < 0.00001). CONCLUSIONS: These findings suggest that co-administration of MRA and ACEI/ARB has beneficial effects on renal outcomes with increasing the incidence of hyperkalemia.

Combination therapy with lamivudine and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker for hepatitis B virus-associated glomerulonephritis with mild to moderate proteinuria: a clinical review of 38 cases.

PURPOSE: The treatment of HBV-associated glomerulonephritis (HBV-GN) is still a challenge in clinical practice now. The objective of this study was to report the pathological characteristics of HBV-GN presenting with mild to moderate proteinuria and to evaluate the therapeutic efficacy of lamivudine (LAM) in combination with angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) as compared to ACEI/ARB monotherapy. METHODS: We conducted a retrospective observational study in HBV-GN patients between 2005 and 2014. The patients were classified into two groups: Group 1 included patients treated with LAM plus ACEI/ARB (n = 20), and group 2, patients treated with ACEI/ARB alone (n = 18). Their clinical and pathological characteristics were collected; we analyzed the therapeutic responses and assessed the correlation between renal and liver pathologies. RESULTS: Our results showed that the most common type of HBV-GN was IgA nephropathy. LAM plus ACEI/ARB therapy was better in reducing 24-h urinary protein excretion, alanine aminotransferase, and aspartate aminotransferase levels, while maintaining the level of kidney function. The proportion of patients who achieved remission (CR + PR) was higher in the LAM plus ACEI/ARB group than in the ACEI/ARB monotherapy group (χ 2 = 5.371, P = 0.035). CONCLUSION: In the HBV-GN patients with mild to moderate proteinuria, LAM plus ACEI/ARB not only improved liver function but also better reduced 24-h proteinuria.

miR-204 regulates epithelial-mesenchymal transition by targeting SP1 in the tubular epithelial cells after acute kidney injury induced by ischemia-reperfusion.

Acute kidney injury (AKI) is a disease where kidney function is lost almost instantaneously; it can develop very rapidly over few hours to maximum of few days. Despite the advent of technology, the clinical management against this disease is very poor, and most of the time it is life-threatening. AKI has been actively regulated by extracellular matrix proteins (ECM), however, its underlying mechanism of regulation during AKI progression is very poorly understood. In this study, we explored the integrated network of mRNA and microRNAs (miRNAs) that maintains the progression of ECM after induction of AKI by lethal ischemia. To identify key regulators of ECM, we screened large number of transcriptomes using laser capture microdissection (LCM) technique in addition to microarray and RT-qPCR. Our result clearly showed that 9 miRNAs including miR-21, miR-483, miR-5115, miR-204e, miR-128, miR-181c, miR-203, miR-204 and miR-204c were highly regulated, out of which miR-204 expression change (decrease) was most drastic during ischemia/reperfusion. Detail mechanistic study utilizing combined experimental and computational approach revealed that TGF-ß signaling pathway was potentially modulated by deregulated miRNA-204 through SP1, where the TGF-ß signaling pathway plays a vital role in ECM regulation. Apart from targeting SP1 and antagonizing epithelial-mesenchymal transition (EMT) signaling our result also showed that miR-204 protects interstitial tissue of renal tubules from chronic fibrotic change. Altogether our study provides sufficient details of how miRNA mediated ECM regulation occur during AKI, which can be effectively utilized in future for better AKI management and diagnosis.

Effect of Xuesaitong soft capsule on hemorrheology and in auxiliarily treating patients with acute cerebral infarction.

OBJECTIVE: To observe the therapeutic effect of Xuesaitong soft capsule (XST) and its effect on platelet counts, coagulation factor 1 (CF1) as well as hemorrheologic indexes in treating patients with acute cerebral infarction (ACI). METHODS: Two hundred and four patients with ACI were assigned into two groups, the control group (n = 96) and the treated group (n = 108). They were all treated with conventional Western medicines, including mannitol, troxerutin, citicoline, piracetam and aspirin, while to the treated group, XST was given additionally through oral intake, twice a day, 2 capsules each time for 8 successive weeks. The clinical efficacy was evaluated according to the nerve function deficits scoring and the changes of platelet count. CF1 and hemorrheological indexes were measured before and after treatment. RESULTS: The total effective rate was 87.0% in the treated group, and 87.5% in the control group, respectively, showing insignificant difference between them. But the markedly effective rate in the treated group (66.7%) was significantly higher than that in the control group (27.1%, P < 0.01). The count of platelet was not changed significantly in both groups after treatment, while CF1 in them evidently lowered at the end of the 4th and 8th weeks of treatment, but showed insignificant difference between the two groups. The hematocrit, whole blood viscosity and plasma viscosity in both groups were all improved significantly after treatment, but also showed insignificant difference in comparison of the two groups. CONCLUSION: XST has good efficacy in auxiliary treatment of patients with ACI, though its mechanism remains to be further explored.

Linaclotide, through activation of guanylate cyclase C, acts locally in the gastrointestinal tract to elicit enhanced intestinal secretion and transit.

Linaclotide is a first-in-class, orally administered 14-amino acid peptide that is in development for the treatment of irritable bowel syndrome with constipation and chronic constipation. We have characterized the solution structure of linaclotide, the in vitro binding and agonist activity to guanylate cyclase C receptors, the stability of linaclotide under conditions mimicking the gastric environment, oral bioavailability, and the pharmacodynamic effects in rat models of gastrointestinal transit and intestinal secretion. Nuclear magnetic resonance spectroscopy analysis determined that the molecular structure of linaclotide is stabilized by three intramolecular disulfide bridges. Linaclotide exhibited high affinity and pH-independent binding (K(i): 1.23-1.64 nM) to guanylate cyclase C receptors on human colon carcinoma T84 cells and concomitantly, linaclotide binding resulted in a significant, concentration-dependent accumulation of intracellular cyclic guanosine-3', 5'-monophosphate (cGMP) (EC50:99 nM). Linaclotide was stable after 3 h incubation in simulated gastric fluid (pH 1) and similarly, was completely resistant to hydrolysis by pepsin. Pharmacokinetic analysis of linaclotide showed very low oral bioavailability (0.1%). Orally administered linaclotide elicited a significant, dose-dependent increase in gastrointestinal transit rates in rats at doses of ≥5 µg/kg. Exposure of surgically ligated small intestinal loops to linaclotide induced a significant increase in fluid secretion, accompanied by a significant increase in intraluminal cGMP levels. These results suggest that the guanylate cyclase C agonist linaclotide elicits potent pharmacological responses locally in the gastrointestinal tract, and that orally administered guanylate cyclase C agonists may be capable of improving bowel habits in patients suffering from irritable bowel syndrome with constipation and chronic constipation.

[Comparison of adsorbent with varying arm length and ligand density for the purification of recombinant hepatitis B virus surface antigen].

Novel hydrophobic absorbents were synthesized by immobilizing butyl derivative onto the highly cross-linked agarose beads manufatured in China, which are used as matrix. The effect of the spacer arm length (3C, 8C and 10C) and ligand density (from 13 to 45 micromol/mL) on the hydrophobicity were investigated using purified Hepatitis B surface antigen (HBsAg) expressed by CHO cell lines. Also considering the effects of salt concentration and pH on HBsAg recovery and purification factor, orthogonal experiment design method was used to evaluated the absorbents. The results showed the butyl-S absorbent with the spacer arm length of C8, the ligand density of 22 micromol/mL gel showed the best performance for the separation of HBsAg. Approximately 100% HBsAg recovery and 60 as purification fold were achieved by this media under the operating condition of pH 7.0 and 9% of salt concentrateion.

A methylation-dependent electrostatic switch controls DNA repair and transcriptional activation by E. coli ada.

The transcriptional activity of many sequence-specific DNA binding proteins is directly regulated by posttranslational covalent modification. Although this form of regulation was first described nearly two decades ago, it remains poorly understood at a mechanistic level. The prototype for a transcription factor controlled by posttranslational modification is E. coli Ada protein, a chemosensor that both repairs methylation damage in DNA and coordinates the resistance response to genotoxic methylating agents. Ada repairs methyl phosphotriester lesions in DNA by transferring the aberrant methyl group to one of its own cysteine residues; this site-specific methylation enhances tremendously the DNA binding activity of the protein, thereby enabling it to activate a methylation-resistance regulon. Here, we report solution and X-ray structures of the Cys-methylated chemosensor domain of Ada bound to DNA. The structures reveal that both phosphotriester repair and methylation-dependent transcriptional activation function through a zinc- and methylation-dependent electrostatic switch.