Mccainherndon4303

Secondary metabolites have an important impact on the biocontrol potential of soil-derived microbes. In addition, various microbe-produced chemicals have been suggested to impact the development and phenotypic differentiation of bacteria, including biofilms. The non-ribosomal synthesized lipopeptide of Bacillus subtilis, surfactin, has been described to impact the plant promoting capacity of the bacterium. Here, we investigated the impact of surfactin production on biofilm formation of B. subtilis using the laboratory model systems; pellicle formation at the air-medium interface and architecturally complex colony development, in addition to plant root-associated biofilms. We found that the production of surfactin by B. subtilis is not essential for pellicle biofilm formation neither in the well-studied strain, NCIB 3610, nor in the newly isolated environmental strains, but lack of surfactin reduces colony expansion. Further, plant root colonization was comparable both in the presence or absence of surfactin synthesis. Our results suggest that surfactin-related biocontrol and plant promotion in B. subtilis strains are independent of biofilm formation.The Center for Biofilm Engineering was the first center of excellence focused on biofilms and was originally funded through the Engineering Research Center Program from the U.S. National Science Foundation. After almost 30 years, biofilm continues to be a stand-alone scientific topic of inquiry that has broad implications for fundamental and applied science and engineering of bio-systems. However, much remains to be done, not only for research discovery but also education and outreach, to increase and grow the biofilm paradigm as well as our understanding of the microbial world.Weak acids such as acetic acid and N-acetyl cysteine (NAC) at pH less than their pKa can effectively eradicate biofilms due to their ability to penetrate the biofilm matrix and the cell membrane. However, the optimum conditions for their activity against drug resistant strains, and safety, need to be understood for their application to treat infections or to inactivate biofilms on hard surfaces. Here, we investigate the efficacy and optimum conditions at which weak acids can eradicate biofilms. We compared the efficacy of various mono and triprotic weak acids such as N-acetyl cysteine (NAC), acetic acid, formic acid and citric acid, in eradicating biofilms. We found that monoprotic weak acids/acid drugs can kill mucoid P. aeruginosa mucA biofilm bacteria provided the pH is less than their pKa, demonstrating that the extracellular biofilm matrix does not protect the bacteria from the activity of the weak acids. Triprotic acids, such as citric acid, kill biofilm bacteria at pH less then pKa1. However, at a pH between pKa1 and pKa2, citric acid is effective in killing the bacteria at the core of biofilm microcolonies but does not kill the bacteria on the periphery. The efficacy of a monoprotic weak acid (NAC) and triprotic weak acid (citric acid) were tested on biofilms formed by Klebsiella pneumoniae KP1, Pseudomonas putida OUS82, Staphylococcus aureus 15981, P. aeruginosa DK1-NH57388A, a mucoid cystic fibrosis isolate and P. aeruginosa PA_D25, an antibiotic resistant strain. We showed that weak acids have a broad spectrum of activity against a wide range of bacteria, including antibiotic resistant bacteria. Further, we showed that a weak acid drug, NAC, can kill bacteria without being toxic to human cells, if its pH is maintained close to its pKa. Thus weak acids/weak acid drugs target antibiotic resistant bacteria and eradicate the persister cells in biofilms which are tolerant to other conventional methods of biofilm eradication.Procaryotes starve and face myriad stresses. The bulk population actively resists the stress, but a small population weathers the stress by entering a resting stage known as persistence. No mutations occur, and so persisters behave like wild-type cells upon removal of the stress and regrowth; hence, persisters are phenotypic variants. In contrast, resistant bacteria have mutations that allow cells to grow in the presence of antibiotics, and tolerant cells survive antibiotics better than actively-growing cells due to their slow growth (such as that of the stationary phase). In this review, we focus on the latest developments in studies related to the formation and resuscitation of persister cells and propose the guanosine pentaphosphate/tetraphosphate (henceforth ppGpp) ribosome dimerization persister (PRDP) model for entering and exiting the persister state.

Severe asymptomatic hypertension (SAH) is associated with significant health cost, morbidity and mortality.

Establish the nationwide prevalence, trends and associated sociodemographic characteristics of SAH among patients with hypertension in the USA.

We utilized the National Health and Nutrition Examination data collected over five survey cycles (2007-2016). Included were participants aged 20-80 years with self-reported diagnosis of hypertension. SAH was defined as having a mean systolic blood pressure (SBP) ≥180mmHg and/or mean diastolic blood pressure (DBP) ≥120mmHg at the time of examination. The Chi square test was used to compare prevalence across different categories. Associations between sociodemographic variables and SAH were assessed using multivariate binary logistic regression.

The prevalence of SAH among patients with hypertension is 2.15% (95% CI 1.80-2.56), mainly explained by isolated mean SBP≥180mmHg (86% of all cases), with no statistically significant change between 2007 2.66% (95% CI 2.10-3.36) and 20162.61% [95% CI 1.73-3.94), p-trend=0.17. Protein Tyrosine Kinase inhibitor Increasing age (OR 1.07, 95% CI 1.04-1.09), NH Blacks (OR 2.20, 95% CI 1.37-3.54), BMI< 25 (OR 2.52, 95% CI 1.48-4.28), lack of health insurance OR 4.92% (95% CI 2.53-9.54) and never married individuals (OR=2.59%, 95% CI 1.20-5.60) were more likely to have SAH, comparatively. There was no significant association between duration of hypertension and SAH.

The prevalence of SAH in the USA is 2.15% and has been stable over the past decade. Our study underscores the importance of identifying barriers to screening and treatment of hypertension which is a major treatable risk factor for cardiovascular disease.

The prevalence of SAH in the USA is 2.15% and has been stable over the past decade. Our study underscores the importance of identifying barriers to screening and treatment of hypertension which is a major treatable risk factor for cardiovascular disease.