Biofilm Formation and Detachment in Gram-Negative Pathogens Is Modulated by Select Bile Acids

Biofilms are a ubiquitous feature of microbial community structure in both natural and host environments; they enhance transmission and infectivity of pathogens and provide protection from human defense mechanisms and antibiotics. However, few natural products are known that impact biofilm formation or persistence for either environmental or pathogenic bacteria. Using the combination of a novel natural products library from the fish microbiome and an image-based screen for biofilm inhibition, we describe the identification of taurine-conjugated bile acids as inhibitors of biofilm formation against both Vibrio cholerae and Pseudomonas aeruginosa. Taurocholic acid (1) was isolated from the fermentation broth of the fish microbiome-derived strain of Rhodococcus erythropolis and identified using standard NMR and MS methods. Screening of the twelve predominant human steroidal bile acid components revealed that a subset of these compounds can inhibit biofilm formation, induce detachment of preformed biofilms under static conditions, and that these compounds display distinct structure-activity relationships against V. cholerae and P. aeruginosa. Our findings highlight the significance of distinct bile acid components in the regulation of biofilm formation and dispersion in two different clinically relevant bacterial pathogens, and suggest that the bile acids, which are endogenous mammalian metabolites used to solubilize dietary fats, may also play a role in maintaining host health against bacterial infection.     

Conservation of the photosynthesis gene cluster in Rhodospirillum centenum

Intraspecies and intergenus complementation analysis were utilized to demonstrate that photosynthesis genes are clustered in distantly related purple photosynthetic bacteria. Specifically, we show that the linkage order for genes involved in bacteriochlorophyll and carotenoid biosynthesis in Rhodospirillum centenum are arranged essentially as in Rhodobacter capsulatus and Rhodobacter sphaeroides. In addition, the location and relative distance observed between the puf and puh operons which encode for light harvesting and reaction-centre structural genes are also conserved between these species. Conservation of the photosynthesis gene cluster implies either that there are structural or regulatory constraints that limit rearrangement of the photosynthesis gene cluster or that there may have been lateral transfer of the photosynthesis gene cluster among different species of phototrophic bacteria.     

Effects of gestational weight gain and body mass index on obstetric outcome

Abstract It is already known that maternal overweight, obesity, and morbid obesity are associated with adverse obstetric and neonatal outcomes. To assess the prevalence of overweight and obesity, and the impact of body mass index (BMI) on maternal and neonatal outcomes in Turkey. The study population consisted of 698 singleton pregnancies whose height and weight follow up were performed from the first trimester of pregnancy and whose deliveries were monitored in Trabzon, Turkey in July 2014–June 2015. The data obtained during the study were evaluated using SPSS 21 package program. The differences in variables were assessed by Chi-square-test for categorical data or by One-way Anova test for continuous data. The results were evaluated at a confidence interval of 95% and at a significance level of p?<?0.05. According to the BMI of the women in the study, 68.8% were in normal weight, 20.6% were overweight, 3.9% were obese, and the majority was in the 20–29 age group and 8–15.9?kg. The rate of cesarean, instrumental delivery, induction, episiotomy, late breastfeeding, low apgar (<7 at 5?min), neonatal intensive care unit admission requirement, the newborn at 4000?g or more in overweight (BMI 25–29.9) and obese (BMI?≥?30) pregnancies was higher and the first and second phases of labor were longer (p?<?0.05). The study showed that as the pre-pregnancy body mass index and gestational weight gain increased the rates of cesarean section and interventional delivery increased and the neonatal need for neonatal intensive care unit increased.     

Efficacy of Boric Acid,Monopotassium Phosphate and Sodium Metabisulfite on the Control of Apple Scab

In vitro experiments indicated that boric acid, monopotassium phosphate, sodium metabisulfite and synthetic fungicide fluopyram + tebuconazole were effective in inhibiting conidia germination and germ‐tube elongation of Venturia inaequalis. Monopotassium phosphate even at the highest concentration used in the study reduced conidia germination and germ‐tube elongation of V. inaequalis by 22.1% and 28.8%, respectively; however, the difference between two compounds at lower concentrations except 0.05% (for conidia germination) and 0.1% (for germ‐tube elongation) of boric acid was statistically significant (P ≤ 0.05). Complete inhibition was achieved by 0.01% sodium metabisulfite, 0.035% fluopyram + tebuconazole and 0.2% boric acid. Two orchard trials were conducted on the highly susceptible cv. Mutsu to apple scab to ascertain the efficacy of 0.2% boric acid, 0.5% monopotassium phosphate, 0.5% sodium metabisulfite and 0.035% fluopyram + tebuconazole for the control of apple scab. In both 2013 and 2014, except for the applications of monopotassium phosphate and sodium metabisulfite, the applications of boric acid and fluopyram + tebuconazole to trees at 10‐day intervals significantly reduced disease incidence and severity on leaves and fruit compared to the water‐treated control. In both years, the efficacy of boric acid and fluopyram + tebuconazole treatments was similar in reducing both disease incidence and severity on leaves and fruit in all monthly assessments from July to September. All treatments were neither phytotoxic to leaves and fruit nor did they adversely affect quality parameters of harvested fruit. These results show that boric acid treatment may be applied as an alternative chemical for the control of apple scab.