PP2A Antagonizes Phosphorylation of Bazooka by PAR-1 to Control Apical-Basal Polarity in Dividing Embryonic Neuroblasts

SummaryBazooka/Par-3 (Baz) is a key regulator of cell polarity in epithelial cells and neuroblasts (NBs). Phosphorylation of Baz by PAR-1 and aPKC is required for its function in epithelia, but little is known about the dephosphorylation mechanisms that antagonize the activities of these kinases or about the relevance of Baz phosphorylation for NB polarity. We found that protein phosphatase 2A (PP2A) binds to Baz via its structural A subunit. By using phospho-specific antibodies, we show that PP2A dephosphorylates Baz at the conserved serine residue 1085 and thereby antagonizes the kinase activity of PAR-1. Loss of PP2A function leads to complete reversal of polarity in NBs, giving rise to an “upside-down” polarity phenotype. Overexpression of PAR-1 or Baz, or mutation of 14-3-3 proteins that bind phosphorylated Baz, causes essentially the same phenotype, indicating that the balance of PAR-1 and PP2A effects on Baz phosphorylation determines NB polarity

The relationship of dieting severity and bulimic behaviors to alcohol and other drug use in young women

Patients with bulimia nervosa frequently have problems with alcoholism and other substance abuse. The goal of this study was to assess whether this relationship between eating abnormalities and substance abuse extends to subthreshold levels of dieting and substance use. A self-administered questionnaire assessing dieting and substance use (alcohol, cigarettes, and marijuana) was completed by 1,796 women prior to their freshman year in college. Using a scale derived from DSM-III-R criteria for bulimia nervosa and previous research in this population, subjects were categorized as nondieters, casual, intense, severe, at-risk, or bulimic dieters. The relationship between the dieting-severity category and frequency and intensity of alcohol use and frequency of marijuana and cigarette use was assessed. DSM-III-R criteria for bulimia nervosa were met by 1.6% of the women. Only 13.8% of these women were nondieters. Increasing dieting severity was positively associated with increasing prevalence of alcohol, cigarette, and marijuana use and with increasing frequency and intensity of alcohol use. The bulimic and at-risk dieters were similar in their alcohol and drug use. The relationship between eating disorders and alcoholism and other substance abuse noted in clinical populations extends in a continuous, graded manner to subthreshold levels of dieting and substance use behaviors. Dieting-related attitudes and behaviors in young women may be related to increased susceptibility to alcohol and drug abuse.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30340/1/0000742.pd

Taste responses and preferences for sweet high-fat foods: Evidence for opioid involvement

Preferences and cravings for sweet high-fat foods observed among obese and bulimic patients may involve the endogenous opioid peptide system. The opioid antagonist naloxone, opioid agonist butorphanol, and saline placebo were administered by intravenous infusion to 14 female binge eaters and 12 normal-weight controls. Eight of the binge eaters were obese. During infusion, the subjects tasted 20 sugar/fat mixtures and were allowed to select and consume snack foods of varying sugar and fat content. Naloxone reduced taste preferences relative to baseline in both binge eaters and controls. Total caloric intake from snacks was significantly reduced by naloxone in binge eaters but not in controls. This reduction was most pronounced for sweet high-fat foods such as cookies or chololate. No consistent effects on taste preferences or food intakes were observed with butorphanol. Endogenous opioid peptides may be involved in mediating taste responses and preferences for palatable foods, notably those rich in sugar and fat.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30234/1/0000628.pd

Scientific Opportunities to Reduce Risk in Nuclear Process Science

Cleaning up the nation’s nuclear weapons complex remains as one of the most technologically challenging and financially costly problems facing the U.S. Department of Energy (DOE). Safety, cost, and technological challenges have often delayed progress in retrieval, processing, and final disposition of high-level waste, spent nuclear fuel, and challenging materials. Some of the issues result from the difficulty and complexity of the technological issues; others have programmatic bases, such as contracting strategies that may provide undue focus on near-term, specific clean-up goals or difficulty in developing and maintaining stakeholder confidence in the proposed solutions. We propose that independent basic fundamental science research focused on the full cleanup life-cycle offers an opportunity to help address these challenges by providing 1) scientific insight into the fundamental mechanisms involved in currently selected processing and disposal options, 2) a rational path to the development of alternative technologies should the primary options fail, 3) confidence that models that predict long-term performance of different disposal options are based upon the best available science, 4) fundamental science discovery that enables transformational solutions to revolutionize the current baseline processes

Integration of priority population, health and nutrition interventions into health systems: systematic review

Objective of the study was to assess the effects of strategies to integrate targeted priority population, health and nutrition interventions into health systems on patient health outcomes and health system effectiveness and thus to compare integrated and non-integrated health programmes. Systematic review using Cochrane methodology of analysing randomised trials, controlled before-and-after and interrupted time series studies. We defined specific strategies to search PubMed, CENTRAL and the Cochrane Effective Practice and Organisation of Care Group register, considered studies published from January 1998 until September 2008, and tracked references and citations. Two reviewers independently agreed on eligibility, with an additional arbiter as needed, and extracted information on outcomes: primary (improved health, financial protection, and user satisfaction) and secondary (improved population coverage, access to health services, efficiency, and quality) using standardised, pre-piloted forms. Two reviewers in the final stage of selection jointly assessed quality of all selected studies using the GRADE criteria. Of 8,274 citations identified 12 studies met inclusion criteria. Four studies compared the benefits of Integrated Management of Childhood Illnesses in Tanzania and Bangladesh, showing improved care management and higher utilisation of health facilities at no additional cost. Eight studies focused on integrated delivery of mental health and substance abuse services in the United Kingdom and United States of America. Integrated service delivery resulted in better clinical outcomes and greater reduction of substance abuse in specific sub-groups of patients, with no significant difference found overall. Quality of care, patient satisfaction, and treatment engagement were higher in integrated delivery models. Targeted priority population health interventions we identified led to improved health outcomes, quality of care, patient satisfaction and access to care. Limited evidence with inconsistent findings across varied interventions in different settings means no general conclusions can be drawn on the benefits or disadvantages of integrated service delivery

Investigating Mycobacteriophage-Host Protein Interactions

Mycobacteriophages are viruses that infect bacterial cells of the genus Mycobacterium. They possess a multitude of unfamiliar or novel genes – genes encoding protein sequences that do not resemble any previously studied proteins – and thus encode products with functions not readily predicted. We hypothesized that some of those genes encode products that interfere with the normal metabolism of the host cell, possibly through specific phage-host protein-protein interactions, and thus have a role in enabling phage infection. Further, we predicted that those gene products when expressed alone in host cells would still be toxic and impair cell growth. We have investigated unfamiliar genes in two genetically distinct mycobacteriophages, Pumpkin and Vix, and have identified 4 single genes (Pumpkin_115, Pumpkin_119, Pumpkin_142, Vix_80) and several small genomic regions (Pumpkin gene segment 130-133 and Vix gene segments 65-66, 68-72, 87-88) that are cytotoxic to M. smegmatis. We are taking a multi-prong approach to further identify the specific functions associated with these genes and their products and to determine their roles in the infection process: 1) we have identified mutants of M. smegmatis that are resistant to the expression of those genes, 2) we are using E. coli- expressed phage genes to screen for interacting host proteins, 3) we are collecting microscopy data that could identity phage interruption of normal cellular function, and 4) we are in the process of deleting these genes from the phage genome to determine the effect on infection. 24-hour expression of individual cytotoxic phage genes in M. smegmatis resulted in a significant increase in mean host cell length and some subtle effects on cell shape. Ongoing analysis of the mutants has identified a common mechanism of resistance to distinct phage gene expression, while protein-protein interaction studies have not yet identified a potential host target involved in translation

Temperature Effects on a M. tuberculosis-infectious Subset of Mycobacteriophages

Mycobacteriophages are viruses that infect mycobacterial hosts. Over 1300 mycobacteriophages have been organized into at least 34 distinct groupings or clusters based on genomic sequence similarity. Some mycobacteriophages from Clusters A and K can also infect Mycobacterium tuberculosis, a distinction of potential medical importance. Recently, Hope College SEA-PHAGES students have been isolating predicted Cluster K phages at a higher frequency (≥ 2x) after changing the isolation temperature from 37°C to 32°C. Additionally, these phages were unable to propagate at 42°C. PCR analysis supported a Cluster K classification for many predicted Cluster K phages isolated at 32°C, but for only one of the phages (Ruthiejr) isolated at 37°C. Interestingly, Ruthiejr does propagate at 42°C. We hypothesized that Cluster K phages may have a relative growth advantage at lower temperatures. We investigated temperature-dependent growth properties of several known and PCR-supported Cluster K mycobacteriophages. We examined phage thermostability, adsorption rate, reproductive cycle time (latent period), and burst size. Stability at 42°C appeared phage-dependent and was not always consistent with growth temperature profiles and/or host adsorption kinetics. For example, phages Bella96 and Krueger, both growth-defective at 42°C, also displayed reduced thermostability and host adsorption kinetics at 42°C compared to lower temperatures. In contrast, phages Polymorphads and Hyperbowlee, also growth defective at 42°C, were nonetheless stable at 42°C. Notably, Hyperbowlee also showed almost no host adsorption at 42°C. One-step growth analysis of D29 (control), Bella96, and Krueger showed impaired growth of the Cluster K phages at ≥ 37°C compared to D29. These results now suggest that Cluster K phages may have a growth disadvantage at temperatures ≥ 32°C. Our findings provide insight into the growth behavior and temperature sensitivity of Cluster K phages and may lead to discoveries about M. smegmatis and M. tuberculosis infection by mycobacteriophages