Genetic and genomic diversity of NheABC locus from Bacillus strains.

Non-hemolytic enterotoxin (NHE), a tri-partite, proteinaceous toxin encoded by contiguous nheA, nheB and nheC genes of Bacillus cereus sensu lato (B. cereus s.l.), is considered to be associated with the foodborne diarrheic syndrome. However, B. cereus s.l. includes a number of closely related strains, and the occurrence of NHE among them, and other members of Bacillus is unclear. Consequently, we aimed to determine the distribution and evolution of NHE within Bacillus by confirming the presence of the nheA, B and C sequences and variation within them using published data, and to analyze the genomic and genetic diversity. The phylogenetic tree of NHE proteins (NheA, NheB and NheC) from 81 different B. cereus s.l. strains was constructed. And on the genetic determinants of the NHE toxin did not bring any obvious link between the nheABC genes sequence of a strain and its virulence in the diarrhoeal pathogenesis. Analysis of the genomic diversity of the nheA, B and C loci revealed that their upstream regions were more conserved than the downstream sequences. Multilocus sequence typing schemes (MLST) based on seven concatenated housekeeping genes and nheA, B and C genes of the 75 strains were developed. The neighbor joining phylogenetic tree based on seven housekeeping genes together with nheA, B and C genes was similiar to published Bacillus phylogenetic trees. And on the genetic determinants of the NHE toxin did not bring any obvious link between the nheABC genes sequence of a strain and its virulence in the diarrhoeal pathogenesis.The results indicate that nheA, B and C genes do not affect the diversity of housekeeping genes, and this specific NHE protein does not participate in the diarrheic syndrome.

Air pollution, investor sentiment and stock liquidity.

With the aggravation of air pollution, the impact of air pollution on the stock market, especially from the perspective of investor sentiment, has been of great concern and widely discussed. Based on data from China's A-share listed firms from January 1, 2016, to December 31, 2020, the relationship between urban air pollution and stock liquidity of listed firms and the internal mechanism is examined. Firstly, based on local preference theory, we start by predicting the impact of air pollution on stock liquidity. We, then, build a regression model for air pollution and stock liquidity, introducing the intermediary effect model to detect the relationship between the two and its mechanism. Finally, by subdividing the samples, we discuss the differential impact of air pollution on stock liquidity under different circumstances. We found that when air pollution worsens it reduces stock liquidity. The results of the mechanism analysis show that investor sentiment plays an intermediary role in the process of air pollution affecting stock liquidity, and pessimism induced by air pollution can reduce stock liquidity. Heterogeneity test results show that there are differences in the impact of air pollution on stock liquidity between heavily polluting firms and non-heavily polluting firms, different industries, different city sizes, and different levels of air pollution, has a greater effect in non-heavily polluting enterprises, manufacturing and other industries, medium sized cities and light pollution. The results of this research have important reference value for environmental protection departments to establish and improve air pollution monitoring systems and for listed firms to improve stock liquidity and deal with the environmental financial risks appropriately.

Association between homocysteine level and the risk of diabetic retinopathy: a systematic review and meta-analysis.

BACKGROUND: Previous studies have demonstrated that elevated homocysteine (Hcy) level represents an independent risk factor for macrovascular disease. However, the relationship between hyperhomocysteinemia and the progression of diabetic retinopathy in patients remains controversial. Hence, the purpose of this systematic review and meta-analysis was to explore any potential association between Hcy and the risk of diabetic retinopathy. METHODS: PubMed, Embase, and the Cochrane Library databases were searched to screen studies that fulfilled the inclusion criteria from date of database inception to November 2017. The summary odds ratio (OR) with 95% confidence intervals (CIs) was used to calculate the pooled effect estimate for the relationship between Hcy and diabetic retinopathy risk. Sensitivity, subgroup analyses, and publication bias were also assessed. RESULTS: Eleven studies involving a total of 2184 diabetic patients were included in the meta-analysis. The summary OR suggested that increased Hcy level in diabetic patients was associated with an increased risk of diabetic retinopathy (OR 1.62; 95% CI 1.29-2.03; p < 0.001). Although significant heterogeneity was detected among the included studies, the findings of sensitivity analysis remained statistically significant. Subgroup analyses found a significant association between Hcy and diabetic retinopathy in most subsets, but no significant association was found if the sample size was < 100, participants had type 1 diabetes mellitus, and the study quality was low. CONCLUSIONS: The findings of this study suggested that elevated Hcy level was associated with an increased risk of diabetic retinopathy, especially in type 2 diabetic patients. This finding may help diabetic patients to achieve effective management strategy to prevent the progression of diabetic retinopathy.

A uniform HPLC method developed for the analysis of Salvia miltiorrhiza, Panax notoginseng, and Fufang Danshen.

Fufang Danshen (FFDS) is a famous typical Chinese complex prescription, which is mainly composed of Radix Salvia miltiorrhiza Bunge (SM) and Radix Panax notoginseng (PN). An HPLC method is developed to analyze SM, PN, and FFDS effectively; the effective analysis is achieved by using a gradient elution procedure with a mobile phase consisting of acetonitrile and 0.025% aqueous phosphoric acid (v/v). Through this method, 33 peaks in FFDS are clearly exhibited, and the components that make up the 33 peaks in FFDS are evaluated. Also, the chemical ingredients are compared between the single herbs (SM and PN) and the complex prescription (FFDS). The result indicate that the chemical ingredients in FFDS are not simply a combination of SM and PN. In addition, the HPLC method is suitable for the routine quality control of SM, PN, and FFDS, which could present a uniform quality control method for single medicines and one of the most commonly used Traditional Chinese Medicine-complex prescriptions.

Identification of phenolic constituents in Radix Salvia miltiorrhizae by liquid chromatography/electrospray ionization mass spectrometry.

The phenolic components from Radix Salvia miltiorrhizae Bunge, a well-known herbal medicine (Dan-Shen in Chinese), have been investigated by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). HPLC analyses were performed on a reversed-phase C18 column using gradient elution. In the ESI mass spectra a predominant [M-H]- ion was observed in negative mode and provided molecular mass information. ESI-MS/MS spectra of the [M-H]- ions were used for structural analysis, based on the spectra of standards. It was found that caffeic acid and its monomeric analogs containing a carboxyl group readily lost CO2, while dimers, trimers and tetramers of caffeic acid expelled successively danshensu or caffeic acid or their esters. Twenty-eight phenolic compounds in S. miltiorrhizae were characterized, of which eight compounds were positively identified by comparison with standards. The remaining twenty phenolics for which standards were not available were tentatively identified based on their UV spectra and MS/MS fragmentation characteristics.

[Influence of compatibility ratio of Fufang Danshen on the dissolution of Danshen compositions].

A high performance liquid chromatographic (HPLC) method has been developed using peak ratio to compare the Danshen ingredients with varying peak ratios of Danshen (Salvia miltiorrhiza Bunge.) to Sanqi (Panax Notoginseng) from 10:0 to 1:10 in Fufang Danshen which is composed of Danshen and Sanqi. The experimental results show that the contents of major components of all samples decocted together are higher than those of Danshen. The contents of Danshen major components are the highest in classic formula (the mass ratio of Danshen to Sanqi is 5:3). Therefore, Danshen decocted together with Sanqi at a ratio of 5:3 can increase the dissolution ability of Danshen ingredients. This, therefore, could constitute a solid rationale to the compatibility rule in Chinese traditional medicine with both scientific merits and intrinsic reasoning.