ABSTRACT
Candida albicans is an important opportunistic fungal pathogen of humans. Phenotypic plasticity is a typical biological feature of C. albicans, which is associated with pathogenicity, host adaptation, and sexual reproduction. Biofilm of C. albicans is a complex community formed by different morphological types of cells (yeast, hyphae and pseudohyphae) and secreted extracellular matrix. C. albicans biofilms are intrinsically resistant to antifungal drugs, the host immune system, and environmental stresses. Biofilm is an important virulence factor and a major clinical challenge. With the development of new technologies in global gene expression profiles and genetic manipulation, the regulatory mechanisms that govern C. albicans biofilm development and drug resistance become more and more clear. Major regulatory mechanisms involve the MAPK and cAMP signaling pathways and transcriptional regulators such as Bcr1 and Tec1. In addition, morphological transitions and sexual reproduction are also involved in the regulation of biofilm development. In this review, we focus on the genetic regulatory mechanisms of biofilm including the roles of cell-wall related proteins, transcription factors, and the MTL locus. In the last section, we also summarize the mechanisms of drug resistance of biofilm in C. albicans.
ABSTRACT
Objective To evaluate whether Vitamin B supplementation could prevent ischemic stroke recurrence.Methods Randomized controlled trials (RCTs) observing Vitamin B supplementation in patients with stroke was performed in databases including ScienceDirect, PubMed/Medline, China National Knowledge Infrastructure, Chinese Biomedical Data-Base, Wanfang Database, and VIP Chinese Science and Technology Journal Database to find related studies in English or Chinese published before August 2016. The patients in control group received a placebo or basic therapy without Vitamin B, and those in experimental group was treated with Vitamin B alone or Vitamin B on the basis of conventional treatment. The data were collected by two researchers independently and the quality of studies was assessed by the modified Jadad Scale. The Meta-analysis was performed using Stata 12.0, funnel plot was drawn, and Egger and Begg regressions were used to evaluate the publication bias, and sensitivity was also analyzed. Results Seven RCTs studies were enrolled to analyze with a total number of 9846 stroke patients, 4755 patients in control group, and 5091 in experimental group, respectively. ① Vitamin B supplementation for prevention of recurrent stroke: heterogeneity test results showed a heterogeneity in literatures enrolled (I2 = 62.9%,P = 0.009), and a random effect model was used for Meta-analysis. It was shown that the incidence of recurrent stroke in the experimental group was significantly lower than that in the control group [pooled relative risk(RR) = 0.64, 95% confidence interval (95%CI) = 0.47-0.87], which indicated that the supplementation of Vitamin B could prevent the recurrence of stroke. Cumulative Meta-analysis showed that Vitamin B supplementation exhibited positive effects in the prevention stroke recurrence from 2012. The 95%CI tended to be stable while demonstrating good change trend as sample growing. The publication bias evaluation results showed that the funnel plot was not symmetrical by visual inspection, further quantitative analysis showed thatP value from Egger regression was 0.008, while that from Begg regression was 0.035, bothP 0.05, which indicating that there was no evidence of publication bias in the study included.Conclusions Vitamin B supplementation was associated with a lower risk of recurrent stroke in stroke patients and could significantly improve the quality of secondary prevention of stroke. Furthermore, supplementation of Vitamin B could reduce plasma Hcy levels in stroke patients which might contribute to its effect in preventing stroke recurrence.
ABSTRACT
Objective To develop an in vitro method to determine the effects of drugs on tyrosinase(TYR)activity and screen the inhibitory effects on TYR of14extracted components of Chinese medicinal herbs.Methods The activity of TYR was detected by revised Matsuda's method.Effects of14extracted com-ponents on tyrosinase system were observed in vitro.Results Ten of the14components showed dose-depen-dent down-regulation of tyrosinase activity and melanogenesis.The inhibitory activities of eugenol,curcumin and gallic acid were significantly higher than those of arbutin(P