Metabolic effects of static magnetic fields on Streptococcus pyogenes

This study aimed to develop a simple experimental system utilising bacterial cells to investigate the dose responses resulting from exposures to static magnetic flux densities ranging from 0.05 to 0.5 T on viability, bacterial metabolism and levels of DNA damage in Streptococcus pyogenes. Exposure of S. pyogenes to a field of 0.3 T at 24 degrees C under anaerobic conditions resulted in a significant (P < 0.05) decrease in growth rate, with an increased mean generation time of 199 +/- 6 min compared to the control cells at 165 +/- 6 min (P < 0.05). Conversely, exposure to magnetic fields of 0.5 T significantly accelerated the growth rate at 24 degrees C compared to control cells, with a decreased mean generation time of 147 +/- 4 min (P < 0.05). The patterns of metabolite release from cells incubated in phosphate buffered saline (PBS) at 24 degrees C and exposed to different magnetic flux densities (0.05-0.5 T) were significantly (P < 0.05) altered, compared to non-exposed controls. Concentrations of metabolites, with the exception of aspartic acid (r = 0.44), were not linearly correlated with magnetic flux density, with all other r < 0.20. Instead, "window" effects were observed, with 0.25-0.3 T eliciting the maximal release of the majority of metabolites, suggesting that magnetic fields of these strengths had significant impacts on metabolic homeostasis in S. pyogenes. The exposure of cells to 0.3 T was also found to significantly reduce the yield of 8-hydroxyguanine in extracted DNA compared to controls, suggesting some possible anti-oxidant protection to S. pyogenes at this field strength.     

Binding activities by propiverine and its N-oxide metabolites of L-type calcium channel antagonist receptors in the rat bladder and brain

The present study was undertaken to characterize the binding activities of propiverine and its N-oxide metabolites (1-methyl-4-piperidyl diphenylpropoxyacetate N-oxide: P-4(N → O), 1-methyl-4-piperidyl benzilate N-oxide: DPr-P-4(N → O)) toward L-type calcium channel antagonist receptors in the rat bladder and brain. Propiverine and P-4(N → O) inhibited specific (+)-[³H]PN 200–110 binding in the rat bladder in a concentration-dependent manner. Compared with that for propiverine, the K_i value for P-4(N → O) in the bladder was significantly greater. Scatchard analysis has revealed that propiverine increased significantly K_d values for bladder (+)-[³H]PN 200–110 binding. DPr-P-4(N → O) had little inhibitory effects on the bladder (+)-[³H]PN 200–110 binding. Oxybutynin and N-desethyl-oxybutynin (DEOB) also inhibited specific (+)-[³H]PN 200–110 binding in the rat bladder. Propiverine, oxybutynin and their metabolites inhibited specific [N-methyl-³H]scopolamine methyl chloride ([³H]NMS) binding in the rat bladder. The ratios of K_i values for (+)-[³H]PN 200–110 to [³H]NMS were markedly smaller for propiverine and P-4(N → O) than oxybutynin and DEOB. Propiverine and P-4(N → O) inhibited specific binding of (+)-[³H]PN 200–110, [³H]diltiazem and [³H]verapamil in the rat cerebral cortex in a concentration-dependent manner. The K_i values of propiverine and P-4(N → O) for [³H]diltiazem were significantly smaller than those for (+)-[³H]PN 200–110 and [³H]verapamil. Further, their K_i values for [³H]verapamil were significantly smaller than those for (+)-[³H]PN 200–110. The K_i values of propiverine for each radioligand in the cerebral cortex were significantly (P < 0.05) smaller than those of P-4(N → O). In conclusion, the present study has shown that propiverine and P-4(N → O) exert a significant binding activity of L-type calcium channel antagonist receptors in the bladder and these effects may be pharmacologically relevant in the treatment of overactive bladder after oral administration of propiverine.     

Asperpyrone D and other metabolites of the plant-associated fungal strain Aspergillus tubingensis

Bioactivity-guided fractionation of a cytotoxic extract of Aspergillus tubingensis, a fungal strain occurring in the rhizosphere of the Sonoran desert plant, Fallugia paradoxa, afforded a dimeric naphtho-gamma-pyrone asperpyrone D, nine known naphtho-gamma-pyrones, funalenone, and the cytotoxic cyclic penta-peptide, malformin A1.     

糖丝菌属放线菌研究进展

1984年美国著名放线菌分类学家Labeda建立的糖丝菌属(Saccharothrix),是典型的丝状稀有放线菌重要类群之一。糖丝菌的气生菌丝在孢子形成过程中通常呈现锯齿状形态,细胞壁含meso-二氨基庚二酸,磷酸类脂主要包括磷脂酰乙醇胺,优势甲基萘醌是MK-9(H4)和MK-10(H4),基因组中16S rRNA基因的特异性诊断核苷酸序列为CAC(607–609)和GTG(617–619)。近年来基因组学研究证实,糖丝菌基因组中存在丰富的聚酮合成酶、非核糖体多肽合成酶等基因簇,具有生物合成化学结构新颖、生物活性多样的次生代谢物与酶产物的潜能,且研究证实糖丝菌能够代谢产生已知抗生素的衍生物或新骨架结构的抗生素,如二硫吡咯酮类、内酰胺类、蒽环类和氯霉素等新抗生素,在抗病毒、抑菌和抗肿瘤等方面具有巨大的医药价值。同时,糖丝菌也是工业酶制剂生产菌种资源的新成员,在酶制剂应用方面具有较强的开发潜力,其代谢产生的几丁质酶、纤维素酶等新型活性酶在现代农业以及轻工业等领域有着广泛应用。另外,糖丝菌凭借自身独特的遗传代谢多样性在土壤有机污染物降解和重金属污染修复中扮演着重要角色。结合近期本实验室发表的...     

一株花椒根腐病拮抗菌的分离鉴定及全基因组序列分析

【背景】花椒根腐病的防治一直是生产中难以解决的问题,优良生防菌的筛选是微生物菌剂研发的重要方向。【目的】解析花椒根腐病拮抗菌T-1的遗传信息,深入挖掘其拮抗基因簇资源,揭示该菌的拮抗机制。【方法】采用平板对峙法、形态观察、生理生化测定结合分子生物学等方法进行拮抗菌的分离鉴定,同时对菌株进行全基因组测序,并对其序列进行分析及比较基因组学分析。【结果】分离获得的菌株经鉴定为贝莱斯芽孢杆菌,编号T-1,该菌对花椒根腐病的抑制率可达72%,可使菌丝前端的生长严重受阻,抑菌谱检测和花椒根片的离体拮抗试验结果表明,拮抗菌T-1具有较广的抑菌活性且离体状态下对花椒根片具有一定的拮抗作用。其全基因组序列数据提交到NCBI的SRA数据库中获得登录号为SRX11086663,基因组总长为3 886 726 bp,GC含量为46.42%,全基因组中有4015个编码基因,占总基因组的89.74%,比较基因组学分析结果显示,菌株T-1与贝莱斯芽孢杆菌模式菌株FZB42相似性高,拮抗基因簇预测结果发现B. velezensis T-1基因组序列中有12个编码次级代谢产物基因合成簇,其中8个与已知功能基因簇高度相似...     

欧洲疮痂链霉菌F5的鉴定及其抗菌活性

【背景】木豆(Cajanus cajan)是一种具有多种药理活性的药用植物,目前对其根际功能放线菌的认识和研究有限,有必要对其应用开发潜力进行研究。【目的】从木豆根际土中筛选一株对植物病原菌和常见病原菌具有广谱拮抗活性的放线菌菌株,鉴定菌株的分类地位、相关代谢产物及可能的生物合成途径,为该菌株的开发应用提供数据支撑。【方法】以7种常见植物病原真菌及8种常见病原菌为指示菌,采用平板对峙法和滤纸片扩散法筛选具有广谱抗菌活性的放线菌菌株,基于形态观察与系统发育分析对该菌株进行分类鉴定,并通过高分辨质谱和超高效液相色谱-串联质谱(UPLC-MS/MS)对活性菌株的次生代谢产物进行鉴定与验证。采用PCR扩增菌株聚酮合成酶Ⅰ(polyketide synthase,PKS-Ⅰ)和非核糖体多肽合成酶(non-ribosomal peptide synthetase,NRPS)基因,明确其活性代谢产物可能的生物合成途径。【结果】通过抑菌试验筛选得到拮抗放线菌F5,确定其为欧洲疮痂链霉菌(Streptomyces europaeiscabiei),F5菌株基因组中含有编码PKS-Ⅰ和NRPS合成的相关基...     

Association of metabolites reflecting type III and VI collagen formation with modified Rodnan skin score in systemic sclerosis – a cross-sectional study

Objective: The objective was to investigate blood-based biomarkers of type I (PRO-C1), III (PRO-C3) and VI (PRO-C6) collagen formation in systemic sclerosis (SSc) patients and examine their correlation to modified Rodnan skin score (mRSS).

Methods: Limited (lSSc, n?=?76) and diffuse SSc (dSSc, n?=?41) fulfilling the ACR/EULAR 1980 and 2013 classification criteria for SSc and asymptomatic controls (n?=?9) were included. PRO-C1, PRO-C3 and PRO-C6 were measured in serum.

Results: LSSc compared to dSSc were significantly older, had longer disease duration and lower mRSS. PRO-C3 was higher in early dSSc compared to early lSSc (mean [95 percentile], 27.4 [13.1–39.1] ng/mL vs 14.9 [8.2–28.8] ng/mL, p?=?0.006). PRO-C6 levels were higher in early dSSc compared to early lSSc and late dSSc (early dSSc: 28.2 [10.4–92.3] ng/ml vs early lSSc: 11.0 [6.9–28.5] ng/ml; p?=?0.006 and late dSSc: 12.6 [6.5–25.3] ng/mL, p?=?0.04). No difference was observed with PRO-C1. PRO-C3 and PRO-C6 were moderately correlated with mRSS with R-partials of 0.36 (p?<?0.001) and 0.29 (p?=?0.002), respectively

Conclusion: Measures of type III and VI collagen formation are potential objective biomarkers of fibrosis in systemic sclerosis. These biomarkers could be useful in monitoring the disease and efficacy of treatment.     

Dynamic trajectories of volatile and non‐volatile specialised metabolites in ‘overnight’ fragrant flowers of Murraya paniculata

• Ephemeral flowers, especially nocturnal ones, usually emit characteristic scent profiles within their post‐anthesis lifespans of a few hours. Whether these flowers exhibit temporal variability in the composition and profile of volatile and non‐volatile specialised metabolites has received little attention.
• Flowers of Murraya paniculata bloom in the evenings during the summer and monsoon, and their sweet, intense fragrance enhances the plant's value as an ornamental. We aimed to investigate profiles of both volatile and non‐volatile endogenous specialised metabolites (ESM) in nocturnal ephemeral flowers of M. paniculata to examine whether any biochemically diverse groups of ESM follow distinct patterns of accumulation while maintaining synchrony with defensive physiological functions.
• Targeted ESM contents of M. paniculata flowers were profiled at ten time points at 2‐h intervals, starting from late bud stage (afternoon) up to the start of petal senescence (mid‐morning). Emitted volatiles were monitored continuously within the whole 20‐h period using headspace sampling. The ESM contents were mapped by time point to obtain a highly dynamic and biochemically diverse profile. Relative temporal patterns of ESM accumulation indicated that the active fragrance‐emitting period might be divided into ‘early bloom’, ‘mid‐bloom’ and ‘late bloom’ phases. Early and late bloom phases were characterised by high free radical generation, with immediate enhancement of antioxidant enzymes and phenolic compounds. The mid‐bloom phase was relatively stable and dedicated to maximum fragrance emission, with provision for strong terpenoid‐mediated defence against herbivores. The late bloom phase merged into senescence with the start of daylight; however, even the senescent petals continued to emit fragrance to attract diurnal pollinators.
• Our study suggests that dynamic relations between the different ESM groups regulate the short‐term requirements of floral advertisement and phytochemical defence in this ephemeral flower. This study also provided fundamental information on the temporal occurrence of emitted volatiles and internal pools of specialised metabolites in M. paniculata flowers, which could serve as an important model for pollination biology of Rutaceae, which includes many important fruit crops.

     

Endocrine organs of cardiovascular diseases: Gut microbiota

Gut microbiota (GM) is a collection of bacteria, fungi, archaea, viruses and protozoa, etc. They inhabit human intestines and play an essential role in human health and disease. Close information exchange between the intestinal microbes and the host performs a vital role in digestion, immune defence, nervous system regulation, especially metabolism, maintaining a delicate balance between itself and the human host. Studies have shown that the composition of GM and its metabolites are firmly related to the occurrence of various diseases. More and more researchers have demonstrated that the intestinal microbiota is a virtual ‘organ’ with endocrine function and the bioactive metabolites produced by it can affect the physiological role of the host. With deepening researches in recent years, clinical data indicated that the GM has a significant effect on the occurrence and development of cardiovascular diseases (CVD). This article systematically elaborated the relationship between metabolites of GM and its effects, the relationship between intestinal dysbacteriosis and cardiovascular risk factors, coronary heart disease, myocardial infarction, heart failure and hypertension and the possible pathogenic mechanisms. Regulating the GM is supposed to be a potential new therapeutic target for CVD.     

球毛壳菌H6次级代谢产物及其α-葡萄糖苷酶抑制活性

采用体外α-葡萄糖苷酶抑制模型对一株球毛壳菌H6的发酵液和菌丝体两种乙酸乙酯提取物进行活性评价,结果表明,发酵液乙酸乙酯提取物对α-葡萄糖苷酶具有较强的抑制活性,其IC₅₀值为(510.76±23.46)μg/mL。采用硅胶、Sephadex LH-20、半制备高效液相等色谱技术从其发酵液乙酸乙酯提取物中分离得到12个化合物。通过各种光谱分析,依次鉴定为chaetoviridins A-B(1-2),chaetoglobosins A-D(3-6),chaetoglobosin J(7),chaetoglobosin Q(8),prochaetogobosinsⅠ-Ⅲ(9-11),vibratilicin(12),其中化合物12为首次从毛壳属中分离得到。对化合物进行α-葡萄糖苷酶抑制活性测定发现,化合物12显示弱的抑制活性,其IC₅₀为(1 182.75±19.14)μg/mL。