O-Alkylazoxymycins A-F, Naturally Occurring Azoxy-Aromatic Compounds from Streptomyces sp. Py50.

Six new azoxy-aromatic compounds (o-alkylazoxymycins A-F, 1-6) and two new nitrogen-bearing phenylvaleric/phenylheptanoic acid derivatives (o-alkylphemycins A and B, 7 and 8) were isolated from Streptomyces sp. Py50. Their structures were elucidated based on HRESIMS, NMR, UV spectroscopic analyses, and X-ray crystallographic data. O-Alkylazoxymycins A-F (1-6) are the first natural examples of azoxy compounds with the azoxy bond attached to the ortho-position of the phenylheptanoic acid or phenylvaleric acid moiety. Compounds 1, 5, and 6 were active against Epidermophyton floccosum with MIC50 values ranging from 10.1 to 51.2 µM. A plausible biosynthetic pathway of 2 and 3 was proposed.

The effects of cognitive behavioural therapy on depression and quality of life in patients with maintenance haemodialysis: a systematic review.

BACKGROUND: Depression is highly prevalent among Haemodialysis (HD) patients and is known to results in a series of adverse outcomes and poor quality of life (QoL). Although cognitive behavioural therapy (CBT) has been shown to improve depressive symptoms and QoL in other chronic illness, there is uncertainty in terms of the effectiveness of CBT in HD patients with depression or depressive symptoms. METHODS: All randomised controlled trials relevant to the topic were retrieved from the following databases: CINHAL, MEDLINE, PubMed, PsycINFO and CENTRAL. The grey literature, specific journals, reference lists of included studies and trials registers website were also searched. Data was extracted or calculated from included studies that had measured depression and quality of life using valid and reliable tools -this included mean differences or standardised mean differences and 95% confidence intervals. The Cochrane risk of bias tool was used to identify the methodological quality of the included studies. RESULTS: Six RCTs were included with varying methodological quality. Meta-analysis was undertaken for 3 studies that employed the CBT versus usual care. All studies showed that the depressive symptoms significantly improved after the CBT. Furthermore, CBT was more effective than usual care (MD = - 5.28, 95%CI - 7.9 to - 2.65, P = 0.37) and counselling (MD = - 2.39, 95%CI - 3.49 to - 1.29), while less effective than sertraline (MD = 2.2, 95%CI 0.43 to 3.97) in alleviating depressive symptoms. Additionally, the CBT seems to have a beneficial effect in improving QoL when compared with usual care, while no significant difference was found in QoL score when compared CBT with sertraline. CONCLUSIONS: CBT may improve depressive symptoms and QoL in HD patients with comorbid depressive symptoms. However, more rigorous studies are needed in this field due to the small quantity and varied methodological quality in the identified studies.

Characterization of the N-methyltransferases involved in the biosynthesis of toxoflavin, fervenulin and reumycin from Streptomyces hiroshimensis ATCC53615.

Toxoflavin (1), fervenulin (2), and reumycin (3), known to be produced by plant pathogen Burkholderia glumae BGR1, are structurally related 7-azapteridine antibiotics. Previous biosynthetic studies revealed that N-methyltransferase ToxA from B. glumae BGR1 catalyzed the sequential methylation at N6 and N1 in pyrimido[5,4-e]-as-triazine-5,7(6H,8H)-dione (4) to generate 1. However, the N8 methylation of 4 in the biosynthesis of fervenulin remains unclear. To explore the N-methyltransferases required for the biosynthesis of 1 and 2, we identified and characterized the fervenulin and toxoflavin biosynthetic gene clusters in S. hiroshimensis ATCC53615. On the basis of the structures of intermediates accumulated from the four N-methyltransferase gene inactivation mutants and systematic enzymatic methylation reactions, the tailoring steps for the methylation order in the biosynthesis of 1 and 2 were proposed. The N-methylation order and routes for the biosynthesis of fervenulin and toxoflavin in S. hiroshimensis are more complex and represent an obvious departure from those in B. glumae BGR1.

The critical role of cytochrome c maturation (CCM) system in the tolerance of Xanthomonas campestris pv. campestris to phenazines.

Phenazine-1-carboxylic acid (PCA), a secondary metabolite produced by Pseudomonas spp., exhibits a high inhibitory effect in Xanthomonas oryzae pv. oryzae (Xoo), but less inhibitory effect in Xanthomonas oryzae pv. oryzicola (Xoc), and almost no inhibitory effect in Xanthomonas campestris pv. campestris (Xcc). In our previous study, reactive oxygen species (ROS) scavenging system was reported to be involved in PCA tolerance in Xanthomonas spp. However, the PCA tolerance mechanism of Xanthomonas spp. is unclear. In the current study, we constructed a Tn5-based transposon mutant library in Xcc and four highly PCA-sensitive insertion mutants were obtained. TAIL-PCR further confirmed that the Tn5 transposon was inserted in the cytochrome c maturation (CCM) system (XC_1893, XC_1897) of these mutants. Disruption of the CCM system significantly decreased the growth, motility and tolerance of Xcc to PCA and other phenazines, such as phenazine and 1-OH-phenazine. The CCM system is responsible for the covalent attachment of the apocytochrome and heme. Disruption of the transmembrane thioredox protein (Dsb) pathway (XC_0531), an essential process for the formation of mature apocytochrome, also exhibited a decreased tolerance to PCA, suggesting that the defect of cytochrome c caused decreased tolerance of Xcc to PCA. Meanwhile, disruption of the CCM system or Dsb pathway interfered with the functions of cytochrome c proteins, causing an increased sensitivity to H2O2. Collectively, we concluded that the CCM system and Dsb pathway, regulate the tolerance of Xcc to phenazines by influencing the functions of cytochrome c. Therefore, these results provide important references for revealing the action mechanism of PCA in Xanthomonas spp.

Screening and characterization of Xanthomonas oryzae pv. oryzae strains with resistance to pheazine-1-carboxylic acid.

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) and can be effectively controlled by phenazine-1-carboxylic acid (PCA), an antibiotic secreted by Pseudomonas spp. PCA resistance in Xoo was investigated in this research. Only four PCA-resistant strains were obtained by extensive screening, and the resistance was genetically stable in only one of them (P4). P4 was also resistant to phenazine and 1-hydroxyphezine but not to captan, bismerthiazol, or streptomycin. The following were reduced in P4 relative to the parental wild type: growth, virulence, EPS production, extracellular cellulase production and activity, biofilm formation, and swimming ability. ROS accumulation was reduced, resistance to exogenous H2O2 was increased, and expression of catalase genes and catalase activities were increased in P4, suggesting that PCA resistance in P4 results from a reduction in ROS production and/or an increased ability to metabolize ROS following PCA treatment. Given the low risk of Xoo developing PCA resistance and the reduced virulence and fitness of the resistant strain, PCA can be used in alternation with other common bactericides to control BLB in rice fields.

Lorneic Acid Analogues from an Endophytic Actinomycete.

Our natural products discovery program utilizes endophytic actinomycetes associated with plants and employs biological assays and HPLC-based metabolite profiles as the preliminary screen to identify strains of interest, followed by large-scale fermentation and isolation, leading to new and/or bioactive natural products. Six new trialkyl-substituted aromatic acids, namely, lorneic acids E-J (1-6), together with two known analogues (7 and 8), were isolated and identified from the culture extract of Streptomyces sp. KIB-H1289, an endophytic actinomycete obtained from the inner tissue of the bark of Betula mandshurica Nakai. The structures were characterized by interpretation of their spectroscopic data, mainly 1D and 2D NMR. Among them, compound 5 contains a unique disulfide bond that is presumably derived from N-acetylcysteine. All isolated metabolites were evaluated for their inhibitory activity on tyrosinase.

Inhibition of the JAK2/STAT3/SOSC1 Signaling Pathway Improves Secretion Function of Vascular Endothelial Cells in a Rat Model of Pregnancy-Induced Hypertension.

BACKGROUND/AIMS: The present study aimed to investigate the effects of the JAK2/STAT3/SOSC1 signaling pathway on the secretion function of vascular endothelial cells (VECs) in a rat model of pregnancy-induced hypertension (PIH). METHODS: A PIH rat model was established. Forty-eight pregnant Sprague-Dawley female rats were selected and assigned into four groups: the normal group (normal non-pregnant rats), the non-PIH group (pregnant rats without PIH), the PIH group (pregnant rats with PIH) and the AG490 group (pregnant rats with PIH treated with AG490). Systolic blood pressure (SBP) and urinary protein (UP) were measured. The expressions of JAK2/STAT3/SOSC1 signaling pathway-related proteins in placenta tissues were detect by Western blotting. Radioimmunoassay was applied to detect serum levels of nitric oxide (NO), super oxide dismutase (SOD), placental growth factor (PGF), thromboxane B2 (TXB2) and endothelin (ET). Enzyme-linked immunosorbent assay (ELISA) was used to determine serum levels of interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α). RESULTS: Compared with the normal and non-PIH groups, the PIH and AG490 groups had higher SBP and UP levels at 17th and 25th day of pregnancy. The expressions of p/t-JAK2, p/t-STAT3 and SOSC1 in the PIH and AG490 groups were higher than those in the non-PIH group, while the expressions of p/t-JAK2, p/t-STAT3 and SOSC1 in the AG490 group were lower than those in the PIH group. Compared with the non-PIH group, serum levels of ET, TXB2, IL-6 and TNF-α were increased in the PIH and AG490 groups, while serum levels of NO, SOD, 6-keto-PGF1a and IL-10 levels were reduced. Furthermore, the AG490 had lower serum levels of ET, TXB2, IL-6 and TNF-α and higher serum levels of NO, SOD, 6-keto-PGF1a and IL-10 than those in the PIH group. CONCLUSION: Our study provides evidence that inhibition of the JAK2/STAT3/SOSC1 signaling pathway could improve the secretion function of VECs in PIH rats.

Effects of phenazine-1-carboxylic acid on the biology of the plant-pathogenic bacterium Xanthomonas oryzae pv. oryzae.

Xanthomonas oryzae pv. oryzae (Xoo) is the casual agent of bacterial blight, which is one of the most serious diseases of rice. The antibiotic phenazine-1-carboxylic acid (PCA), which is primarily produced by Pseudomonas spp., was found and previously reported very effective against Xoo. However, the biological effects of PCA on Xoo remain unclear. In this study, we found that PCA increased the accumulation of reactive oxygen species (ROS) and reduced the activities of catalase (CAT) and superoxide dismutase (SOD) in Xoo. Xoo was more sensitive to H2O2 than Xanthomonas oryzae pv. oryzicola (Xoc), and had a much lower expression of CAT genes. In addition, proteomic analysis indicated that PCA inhibited carbohydrate metabolism and nutrient uptake in Xoo, and analysis of carbon source utilization further confirmed that carbohydrate metabolism in Xoo was repressed by PCA. In conclusion, PCA acted as a redox-cycling agent that disturbed the redox balance in Xoo and reduced CAT and SOD activities, resulting in higher accumulation of ROS, altered carbohydrate metabolism, and lower energy production and nutrient uptake. Moreover, a deficient antioxidant system in Xoo made it very sensitive to PCA.

Proteome analysis of the plant-pathogenic bacterium Xanthomonas oryzae pv. oryzae.

The plant-pathogenic bacterium Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of bacterial blight, which is one of the most serious diseases of rice. Xoo has been studied for over one century, and much has been learned about it, but proteomic investigation has been neglected. In this study, proteome reference maps of Xoo were constructed by two-dimensional gel electrophoresis, and 628 spots in the gels representing 469 different protein species were identified with MALDI-TOF/TOF MS. The identified spots were assigned to 15 functional categories according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database and the annotations from the National Center for Biotechnology Information (NCBI) database. The data set has been deposited in the World-2DPAGE database (Database ID: 0044). In addition, comparative proteomic analysis revealed that proteins related to the TonB-dependent transportation system and energy metabolism are involved in the phenazine-1-carboxylic acid resistance in Xoo. In conclusion, we have established a proteome database for Xoo and have used this database in a comparative proteomic analysis that identified proteins potentially contributing to phenazine-1-carboxylic acid resistance in Xoo.

Effect of individualized nutrition interventions on clinical outcomes of pregnant women with gestational diabetes mellitus.

BACKGROUND: Gestational diabetes mellitus (GDM) can lead to excessive pregnancy weight gain (PWG), abnormal glucolipid metabolism, and delayed lactation. Therefore, it is necessary to provide appropriate and effective interventions for pregnant women with GDM. AIM: To clarify the effects of individualized nutrition interventions on PWG, glucolipid metabolism, and lactation in pregnant women with GDM. METHODS: The study population consisted of 410 pregnant women with GDM who received treatment at the Northern Jiangsu People's Hospital of Jiangsu Province and Yangzhou Maternal and Child Health Hospital between December 2020 and December 2022, including 200 who received routine in-terventions [control (Con) group] and 210 who received individualized nutrition interventions [research (Res) group]. Data on PWG, glucolipid metabolism [total cholesterol, (TC); triglycerides (TGs); fasting blood glucose (FPG); glycosylated hemoglobin (HbA1c)], lactation time, perinatal complications (cesarean section, premature rupture of membranes, postpartum hemorrhage, and pregnancy-induced hypertension), and neonatal adverse events (premature infants, fetal macrosomia, hypo-glycemia, and respiratory distress syndrome) were collected for comparative analysis. RESULTS: The data revealed markedly lower PWG in the Res group vs the Con group, as well as markedly reduced TG, TC, FPG and HbA1c levels after the intervention that were lower than those in the Con group. In addition, obviously earlier lactation and statistically lower incidences of perinatal complications and neonatal adverse events were observed in the Res group. CONCLUSION: Individualized nutrition interventions can reduce PWG in pregnant women with GDM, improve their glucolipid metabolism, and promote early lactation, which deserves clinical promotion.

Discovery and Biosynthetic Origin of Quinolizidomycins A and B, Two Quinolizidine Alkaloids from Streptomyces sp. KIB-1714.

Quinolizidomycins A (1) and B (2), two unprecedented quinolizidine alkaloids featuring a tricyclic 6/6/5 ring system, were isolated from Streptomyces sp. KIB-1714. Their structures were assigned by detailed spectroscopic data analyses and X-ray diffraction. Stable isotope labeling experiments suggested that compounds 1 and 2 are derived from lysine, ribose 5-phosphate, and acetate units, which indicates an unprecedented manner of assembly of the quinolizidine (1-azabicyclo[4.4.0]decane) scaffold in quinolizidomycin biosynthesis. Quinolizidomycin A (1) was active in an acetylcholinesterase inhibitory assay.

New insights on the Taenia solium tapeworm using molecular tools: age-based human definitive host prevalence and deliberation on parasite life span.

Information on age-based Taenia solium taeniasis prevalence is crucial for control of cysticercosis. T. solium taeniasis prevalence was determined for a village in Liangshan Prefecture, Sichuan Province, China that was co-endemic for T. solium, Taenia saginata asiatica, and Taenia saginata. Individuals who were Taenia egg-positive by stool microscopy and/or expelled tapeworms or proglottids post-treatment were diagnosed as having taeniasis. Infecting species was identified via multiplex PCR on tapeworm specimens or coproPCR followed by sequencing. In addition, initial stool samples from 10 children with taeniasis suspected of having spontaneous expulsion of tapeworms within the period between diagnosis and treatment were subject to species confirmation via coproPCR and sequencing. Of the 389 study subjects, 194 (49.9%) were diagnosed with taeniasis. Children (< 16 years of age) had a higher T. solium taeniasis prevalence (8.8%) than older individuals (2.5%) (P = 0.0127). Molecular analysis of initial stool samples from 7 of 10 children suspected of spontaneously passing tapeworms indicated 6 infections due to T. solium and 1 infection due to T. saginata. This study found that young children had a higher T. solium taeniasis prevalence than older individuals, providing additional support for the belief that adult T. solium likely has a relatively short lifespan compared to other Taenia species with human definitive hosts.

Engineering Escherichia coli BL21(DE3) derivative strains to minimize E. coli protein contamination after purification by immobilized metal affinity chromatography.

Recombinant His-tagged proteins expressed in Escherichia coli and purified by immobilized metal affinity chromatography (IMAC) are commonly coeluted with native E. coli proteins, especially if the recombinant protein is expressed at a low level. The E. coli contaminants display high affinity to divalent nickel or cobalt ions, mainly due to the presence of clustered histidine residues or biologically relevant metal binding sites. To improve the final purity of expressed His-tagged protein, we engineered E. coli BL21(DE3) expression strains in which the most recurring contaminants are either expressed with an alternative tag or mutated to decrease their affinity to divalent cations. The current study presents the design, engineering, and characterization of two E. coli BL21(DE3) derivatives, NiCo21(DE3) and NiCo22(DE3), which express the endogenous proteins SlyD, Can, ArnA, and (optionally) AceE fused at their C terminus to a chitin binding domain (CBD) and the protein GlmS, with six surface histidines replaced by alanines. We show that each E. coli CBD-tagged protein remains active and can be efficiently eliminated from an IMAC elution fraction using a chitin column flowthrough step, while the modification of GlmS results in loss of affinity for nickel-containing resin. The "NiCo" strains uniquely complement existing methods for improving the purity of recombinant His-tagged protein.

Hypoxia induces FGF2 production by vascular endothelial cells and alters MMP9 and TIMP1 expression in extravillous trophoblasts and their invasiveness in a cocultured model.

The role of fibroblast growth factor 2 (FGF2) secretion by vascular endothelial cells during trophoblast invasion was assessed. The human extravillous trophoblast cell line, TEV-1, and umbilical vein endothelial cell line, HUVE-12, were cocultured under normal and hypoxic conditions. FGF2 expression in HUVE-12 cells and matrix metalloproteinase 9 (MMP9) and tissue inhibitor of metalloproteinase 1 (TIMP1) expression in TEV-1 cells were analyzed using quantitative RT-PCR and Western blot analyses. TEV-1 cell invasion was also examined. FGF2 expression in the HUVE-12 cells cocultured with TEV-1 cells was significantly increased under hypoxic conditions. In the TEV-1 cells cocultured with HUVE-12, hypoxia reduced MMP9 expression and increased TIMP1 expression; it also reduced cell invasion by 43%. However, the expression of MMP9 and TIMP1 and ratio of MMP9/TIMP1 were increased when the TEV-1 cells were cultured alone under hypoxic conditions. These findings suggest that FGF2 release by stressed endothelial cells of uterine spiral arteries play roles in decreasing MMP9 and increasing TIMP1 production in extravillous trophoblasts (EVT) in response to stress, resulting in reduced EVT invasion and possibly shallow implantation of the placenta.

Impact of silencing MMP9 gene on the biological behaviors of trophoblasts.

This study examined the effect of MMP9 gene on the biological behaviors of trophoblasts and explore the relation between MMP9 gene and the "superficial implantation of placenta". In vitro cultured trophoblasts (TEV-1 cells) were transfected with synthesized double-stranded MMP9 RNA (siRNA) by using lipofectamine2000™ technique and the expressions of MMP9 mRNA and protein and the growth and invasiveness of the TEV-1 cells were determined. Our results showed that siRNA transfection could significantly inhibit the expression of MMP9 gene in the TEV-1 cells and the growth and invasiveness of the TEV-1 cells transfected RNA was significantly reduced (P<0.01). We are led to conclude that silencing of MMP9 gene with siRNA can inhibit the growth and invasiveness of trophoblasts and increasing the expression of MMP9 might help prevent and treat preeclampsia.

Early albumin level and mortality in hemodialysis patients: a retrospective study.

BACKGROUND: Hypoalbuminemia is a significant risk factor of cardiovascular disease and all-cause death in patients undergoing conventional hemodialysis (HD). However, the albumin (ALB) level of these dialysis patients runs through the whole process of dialysis, and the prognostic value of serum ALB in the early stage of HD and the relationship between the early ALB value and death in HD patients has not been reported. METHODS: The data of 447 patients with HD were retrospectively analyzed. The patients were stratified into three ALB (g/L) groups: low, ALB ≤34.2; moderate, 34.3< ALB <40.1; high, ALB ≥40.2. Survival trends of the three groups were analyzed by the Kaplan-Meier method. RESULTS: Comparison of the clinical data among the three groups showed a positive correlation between Hb, RBC, K+, Ca2+, Mg2+, and PHOS (P<0.05), but a negative correlation between age and high-sensitivity C-reactive protein (hsCRP) (P<0.05). The ALB level in early HD patients was an independent predictor of death [hazard ratio (HR) =0.945; 95% confidence interval (CI): 0.916-0.976; P=0.000], while age and hsCRP were protective factors (HR =1.048, 95% CI: 1.028-1.067, P=0.000; HR =1.049, 95% CI: 1.024-1.075, P=0.000). The estimated median overall survival (OS) at early HD was 56.00 months in the low ALB group, 83.00 months in the moderate ABL group, and 95.00 months in the high ALB group. The Kaplan-Meier estimate of survival showed a significant difference in OS among the three groups (log-rank P=0.000). CONCLUSIONS: The early ALB level not only reflects the nutritional and chronic inflammation status of HD patients, but can also predict the prognosis, which has guiding significance for the management of HD patients.

Bisaspochalasins A-C: Three Cytochalasan Homodimers with Highly Fused Ring System from an Endophytic Aspergillus flavipes.

Three unprecedented cytochalasan homodimers, bisaspochalasins A-C (1-3), and two known monomers, aspochalasins B and D (4 and 5), were isolated from an endophytic Aspergillus flavipes. Bisaspochalasin A (1) contains a 13-hydroxy-3,24-dioxatricyclo[11.10.11,13.02,15]tetracos-4-one cross-linkage, representing an unprecedented carbon skeleton. Bisaspochalasins B (2) and C (3) share a thioether bridge, while 3 has a peroxy modification at C-7, which may be generated by Schenck-ene photooxygenation. Their structures, including their absolute configurations, were elucidated by HRESIMS, NMR, chemical transformation, and X-ray crystallography. Bisaspochalasin A showed inhibitory activity against human T cell proliferation with an IC50 value of 15.8 µM while maintaining low cytotoxicity to T cells.

Identification and functional analysis of the essential and regulatory light chains of the only type II myosin Myo1p in Saccharomyces cerevisiae.

Cytokinesis in Saccharomyces cerevisiae involves coordination between actomyosin ring contraction and septum formation and/or targeted membrane deposition. We show that Mlc1p, a light chain for Myo2p (type V myosin) and Iqg1p (IQGAP), is the essential light chain for Myo1p, the only type II myosin in S. cerevisiae. However, disruption or reduction of Mlc1p-Myo1p interaction by deleting the Mlc1p binding site on Myo1p or by a point mutation in MLC1, mlc1-93, did not cause any obvious defect in cytokinesis. In contrast, a different point mutation, mlc1-11, displayed defects in cytokinesis and in interactions with Myo2p and Iqg1p. These data suggest that the major function of the Mlc1p-Myo1p interaction is not to regulate Myo1p activity but that Mlc1p may interact with Myo1p, Iqg1p, and Myo2p to coordinate actin ring formation and targeted membrane deposition during cytokinesis. We also identify Mlc2p as the regulatory light chain for Myo1p and demonstrate its role in Myo1p ring disassembly, a function likely conserved among eukaryotes.

Role of a Cdc42p effector pathway in recruitment of the yeast septins to the presumptive bud site.

The septins are GTP-binding, filament-forming proteins that are involved in cytokinesis and other processes. In the yeast Saccharomyces cerevisiae, the septins are recruited to the presumptive bud site at the cell cortex, where they form a ring through which the bud emerges. We report here that in wild-type cells, the septins typically become detectable in the vicinity of the bud site several minutes before ring formation, but the ring itself is the first distinct structure that forms. Septin recruitment depends on activated Cdc42p but not on the normal pathway for bud-site selection. Recruitment occurs in the absence of F-actin, but ring formation is delayed. Mutant phenotypes and suppression data suggest that the Cdc42p effectors Gic1p and Gic2p, previously implicated in polarization of the actin cytoskeleton, also function in septin recruitment. Two-hybrid, in vitro protein binding, and coimmunoprecipitation data indicate that this role involves a direct interaction of the Gic proteins with the septin Cdc12p.