Constitutive Type VI Secretion System Expression Gives Vibrio cholerae Intra- and Interspecific Competitive Advantages

The type VI secretion system (T6SS) mediates protein translocation across the cell membrane of Gram-negative bacteria, including Vibrio cholerae – the causative agent of cholera. All V. cholerae strains examined to date harbor gene clusters encoding a T6SS. Structural similarity and sequence homology between components of the T6SS and the T4 bacteriophage cell-puncturing device suggest that the T6SS functions as a contractile molecular syringe to inject effector molecules into prokaryotic and eukaryotic target cells. Regulation of the T6SS is critical. A subset of V. cholerae strains, including the clinical O37 serogroup strain V52, express T6SS constitutively. In contrast, pandemic strains impose tight control that can be genetically disrupted: mutations in the quorum sensing gene luxO and the newly described regulator gene tsrA lead to constitutive T6SS expression in the El Tor strain C6706. In this report, we examined environmental V. cholerae isolates from the Rio Grande with regard to T6SS regulation. Rough V. cholerae lacking O-antigen carried a nonsense mutation in the gene encoding the global T6SS regulator VasH and did not display virulent behavior towards Escherichia coli and other environmental bacteria. In contrast, smooth V. cholerae strains engaged constitutively in type VI-mediated secretion and displayed virulence towards prokaryotes (E. coli and other environmental bacteria) and a eukaryote (the social amoeba Dictyostelium discoideum). Furthermore, smooth V. cholerae strains were able to outcompete each other in a T6SS-dependent manner. The work presented here suggests that constitutive T6SS expression provides V. cholerae with an advantage in intraspecific and interspecific competition.Canadian Institutes of Health Research (Operating Grant MOP-84473)Alberta Heritage Foundation for Medical Research (Alberta Innovates-Health Solutions, Endowment Fund)National Institutes of Health (U.S.) (grant MD001091-01)National Institutes of Health (U.S.) (grant GM068855-02)Olegario V. Rana FellowshipAlberta Heritage Foundation for Medical Research (Alberta Innovates-Health Solutions Graduate Studentships

Auditory event-related potentials

Auditory event related potentials are electric potentials (AERP, AEP) and magnetic fields (AEF) generated by the synchronous activity of large neural populations in the brain, which are time-locked to some actual or expected sound event

Clinical benefits, referral practice and cost implications of an in-hospital pain service: results of a service evaluation in a London teaching hospital.

BACKGROUND In-hospital pain services (IPS) are commonplace, but evidence of efficacy is inadequate, and patients' pain management in any hospital ward remains problematic. This service evaluation aimed to measure the effect of a contemporary IPS, its appropriate use and cost-efficacy. METHODS Records of 249 adults reviewed by the IPS in an inner London Teaching Hospital over an 8-month period were analysed for demographic data, interventions, workload and change in pain intensity measured by numerical rating scale (NRS). Non-parametric tests were used to evaluate differences between initial and final NRS. Spearman's rank correlation analysis was used to create a correlation matrix to evaluate associations between all identified independent variables with the change in NRS. All strongly correlated variables (ρ > 0.5) were subsequently included in a binary logistic regression analysis to identify predictors of pain resolution greater than 50% NRS and improvement rather than deterioration or no change in NRS. Finally, referral practice and cost of inappropriate referrals were estimated. Referrals were thought to be inappropriate when pain was not optimised by the referring team; they were identified using a set algorithm. RESULTS Initial median NRS and final median NRS were significantly different when a Wilcoxon signed-rank test was applied to the whole cohort; Z = -5.5 (p = 0.000). Subgroup analysis demonstrated no significant difference in the 'mild' pain group; z = -1.1 (p = 0.253). Regression analysis showed that for every unit increase in initial NRS, there was a 62% chance of general and a 33% chance of >50% improvement in final NRS. An estimated annual cost-saving potential of £1546 to £4558 was found in inappropriate referrals and patients experiencing no benefit from the service. DISCUSSION Results suggest that patients with moderate to severe pain benefit most from IPS input. Also pain management resources are often distributed inefficiently. Future research is required to develop algorithms for easy identification of potential treatment responders

Evaluating community-based participatory research to improve community-partnered science and community health

Community-based participatory research; community health research; health disparities; process issues Background: Since 2007, the National Congress of American Indians (NCAI) Policy Research Center (PRC) has partnered with the Universities of New Mexico and Washington to study the science of community-based participatory research (CBPR). Our goal is to identify facilitators and barriers to effective community academic partnerships in American Indian and other communities, which face health disparities. Objectives: We have described herein the scientific design of our National Institutes of Health (NIH)-funded study (2009-2013) and lessons learned by having a strong community partner leading the research efforts. Methods: The research team is implementing a mixed-methods study involving a survey of principal investigators (PIs) and partners across the nation and in-depth case studies of CBPR projects. Results: We present preliminary findings on methods and measures for community-engaged research and eight lessons learned thus far regarding partnership evaluation, advisory councils, historical trust, research capacity development of community partner, advocacy, honoring each other, messaging, and finding. Conclusions: Study methodologies and lessons learned can help community academic research partnerships translate research in communities

Cardiomyocyte cell cycle dynamics and proliferation revealed through cardiac-specific transgenesis of fluorescent ubiquitinated cell cycle indicator (FUCCI).

RATIONALE:Understanding and manipulating the cardiomyocyte cell cycle has been the focus of decades of research, however the ultimate goal of activating mitotic activity in adult mammalian cardiomyocytes remains elusive and controversial. The relentless pursuit of controlling cardiomyocyte mitosis has been complicated and obfuscated by a multitude of indices used as evidence of cardiomyocyte cell cycle activity that lack clear identification of cardiomyocyte "proliferation" versus cell cycle progression, endoreplication, endomitosis, and even DNA damage. Unambiguous appreciation of the complexity of cardiomyocyte replication that avoids oversimplification and misinterpretation is desperately needed. OBJECTIVE:Track cardiomyocyte cell cycle activity and authenticate fidelity of proliferation markers as indicators of de novo cardiomyogenesis in post-mitotic cardiomyocytes. METHODS AND RESULTS:Cardiomyocytes expressing the FUCCI construct driven by the α-myosin heavy chain promoter were readily and uniformly detected through the myocardium of transgenic mice. Cardiomyocyte cell cycle activity peaks at postnatal day 2 and rapidly declines thereafter with almost all cardiomyocytes arrested at the G1/S cell cycle transition. Myocardial infarction injury in adult hearts prompts transient small increases in myocytes progressing through cell cycle without concurrent mitotic activity, indicating lack of cardiomyogenesis. In comparison, cardiomyogenic activity during early postnatal development correlated with coincidence of FUCCI and cKit+ cells that were undetectable in the adult myocardium. CONCLUSIONS:Cardiomyocyte-specific expression of Fluorescence Ubiquitination-based Cell Cycle Indicators (FUCCI) reveals previously unappreciated aspects of cardiomyocyte cell cycle arrest and biological activity in postnatal development and in response to pathologic damage. Compared to many other methods and model systems, the FUCCI transgenic (FUCCI-Tg) mouse represents a valuable tool to unambiguously track cell cycle and proliferation of the entire cardiomyocyte population in the adult murine heart. FUCCI-Tg provides a desperately needed novel approach in the armamentarium of tools to validate cardiomyocyte proliferative activity that will reveal cell cycle progression, discriminate between cycle progression, DNA replication, and proliferation, and provide important insight for enhancing cardiomyocyte proliferation in the context of adult myocardial tissue

Vibrio cholerae Requires the Type VI Secretion System Virulence Factor VasX To Kill Dictyostelium discoideum ▿†

The type VI secretion system (T6SS) is recognized as an important virulence mechanism in several Gram-negative pathogens. In Vibrio cholerae, the causative agent of the diarrheal disease cholera, a minimum of three gene clusters—one main cluster and two auxiliary clusters—are required to form a functional T6SS apparatus capable of conferring virulence toward eukaryotic and prokaryotic hosts. Despite an increasing understanding of the components that make up the T6SS apparatus, little is known about the regulation of these genes and the gene products delivered by this nanomachine. VasH is an important regulator of the V. cholerae T6SS. Here, we present evidence that VasH regulates the production of a newly identified protein, VasX, which in turn requires a functional T6SS for secretion. Deletion of vasX does not affect export or enzymatic function of the structural T6SS proteins Hcp and VgrG-1, suggesting that VasX is dispensable for the assembly of the physical translocon complex. VasX localizes to the bacterial membrane and interacts with membrane lipids. We present VasX as a novel virulence factor of the T6SS, as a V. cholerae mutant lacking vasX exhibits a phenotype of attenuated virulence toward Dictyostelium discoideum