Uneven distribution of cobamide biosynthesis and dependence in bacteria predicted by comparative genomics.

The vitamin B12 family of cofactors known as cobamides are essential for a variety of microbial metabolisms. We used comparative genomics of 11,000 bacterial species to analyze the extent and distribution of cobamide production and use across bacteria. We find that 86% of bacteria in this data set have at least one of 15 cobamide-dependent enzyme families, but only 37% are predicted to synthesize cobamides de novo. The distribution of cobamide biosynthesis and use vary at the phylum level. While 57% of Actinobacteria are predicted to biosynthesize cobamides, only 0.6% of Bacteroidetes have the complete pathway, yet 96% of species in this phylum have cobamide-dependent enzymes. The form of cobamide produced by the bacteria could be predicted for 58% of cobamide-producing species, based on the presence of signature lower ligand biosynthesis and attachment genes. Our predictions also revealed that 17% of bacteria have partial biosynthetic pathways, yet have the potential to salvage cobamide precursors. Bacteria with a partial cobamide biosynthesis pathway include those in a newly defined, experimentally verified category of bacteria lacking the first step in the biosynthesis pathway. These predictions highlight the importance of cobamide and cobamide precursor salvaging as examples of nutritional dependencies in bacteria

Effect of Metformin on miR-146a Expression

Sjögren’s Syndrome (SjS) is an autoimmune disorder that affects secretory glands in the human body, restricting their function and causing extreme dryness in areas like the mouth and eyes. miR-146a is an anti-inflammatory microRNA that targets the NFκB activation pathway. Previous studies have shown that SjS patients have increased miR-146a expression, despite having high levels of inflammation. The objective of this study was to investigate whether metformin, a diabetes drug with a wide variety of effects and potential functions, reduces levels of miR-146a expression. Metformin is known to reduce inflammation by inhibiting the activation of NFκB. THP-1 human monocytes were treated with various concentrations of metformin ranging from 12.5uM to 200uM. The cells were treated for 24 hours before total RNA was isolated, and qRT-PCR was utilized to compare miR-146a expression in metformin-treated versus untreated cells. Our results showed a dose-dependent decrease of miR-146a expression in the presence of metformin. These results are reasonable since miR-146a expression is dependent on NFκB activation, and metformin is known to inhibit the activation of NFκB. Further studies will investigate metformin’s ability to suppress inflammation in varying conditions

PucC and LhaA direct efficient assembly of the light-harvesting complexes in <i>Rhodobacter sphaeroides</i>

The mature architecture of the photosynthetic membrane of the purple phototroph Rhodobacter sphaeroides has been characterised to a level where an atomic-level membrane model is available, but the roles of the putative assembly proteins LhaA and PucC in establishing this architecture are unknown. Here we investigate the assembly of light-harvesting LH2 and reaction centre-light-harvesting1-PufX (RC-LH1-PufX) photosystem complexes using spectroscopy, pull-downs, native gel electrophoresis, quantitative mass spectrometry and fluorescence lifetime microscopy to characterise a series of lhaA and pucC mutants. LhaA and PucC are important for specific assembly of LH1 or LH2 complexes, respectively, but they are not essential; the few LH1 subunits found in ΔlhaA mutants assemble to form normal RC-LH1-PufX core complexes showing that, once initiated, LH1 assembly round the RC is cooperative and proceeds to completion. LhaA and PucC form oligomers at sites of initiation of membrane invagination; LhaA associates with RCs, bacteriochlorophyll synthase (BchG), the protein translocase subunit YajC and the YidC membrane protein insertase. These associations within membrane nanodomains likely maximise interactions between pigments newly arriving from BchG and nascent proteins within the SecYEG-SecDF-YajC-YidC assembly machinery, thereby co-ordinating pigment delivery, the co-translational insertion of LH polypeptides and their folding and assembly to form photosynthetic complexes. LhaA and PucC form oligomers at the sites where invagination of the cytoplasmic membranes is initiated, and they play important roles in photosystem assembly in the purple phototrophic bacterium Rhodobacter sphaeroides. Establishing the architecture of the photosynthetic membrane involves interplay between LhaA, reaction centre complexes, bacteriochlorophyll synthase, the protein translocase subunit YajC, and the YidC membrane protein insertase. These associations likely coordinate the delivery of pigments and the membrane insertion, folding and assembly of photosystem polypeptides

Behavioral alterations and Fos protein immunoreactivity in brain regions of bile duct-ligated cirrhotic rats

Hepatic encephalopathy (HE) encompasses a variety of neuropsychiatric symptoms, including anxiety and psychomotor dysfunction. Although HE is a frequent complication of liver cirrhosis, the neurobiological substrates responsible for its clinical manifestations are largely unclear. In the present study, male Wistar rats were bile duct-ligated (BDL), a procedure which induces liver cirrhosis, and on the 21st day after surgery tested in the elevated plus-maze (EPM) and in an open field for anxiety and locomotor activity measurements. Analysis of Fos protein immunoreactivity (Fos-ir) was used to better understand the neurobiological alterations present in BDL animals. Plasma levels of ammonia were quantified and histopathological analysis of the livers was performed. BDL rats showed a significant decrease in the percentage of entries and time spent in the open arms of the EPM, an anxiogenic effect. These animals also presented significant decreases in Fos-ir in the lateral septal nucleus and medial amygdalar nucleus. Their ammonia plasma levels were significantly higher when compared to the sham group and the diagnosis of cirrhosis was confirmed by histopathological analysis. These results indicate that the BDL model induces anxiogenic results, possibly related to changes in the activation of anxiety-mediating circuitries and to increases in ammonia plasma levels.A Encefalopatia hepática (HE) engloba uma variedade de sintomas neuropsiquiátricos, incluindo ansiedade e disfunção psicomotora. Embora seja uma complicação frequente da cirrose hepática, os substratos neurobiológicos responsáveis por suas manifestações clínicas são em grande parte desconhecidos. No presente estudo, ratos Wistar machos foram submetidos ao procedimento cirúrgico de ligação e secção do ducto biliar (BDL; bile-duct ligation), para indução da cirrose hepática e, no 21º dia após a cirurgia, submetidos aos testes comportamentais no labirinto em cruz elevado (LCE) e campo aberto para avaliação da ansiedade e atividade locomotora. A análise da imunorreatividade à proteína Fos (Fos-ir) foi utilizada para melhor compreender as alterações neurobiológicas presentes nos animais do grupo BDL. Foi realizada a quantificação da concentração de amônia plasmática e análise histopatológica dos fígados. Os ratos do grupo BDL mostraram diminuição significativa na porcentagem de entradas e tempo gasto nos braços abertos do LCE, caracterizando efeito ansiogênico. Estes animais também apresentaram redução significativa na Fos-ir no núcleo septal lateral e núcleo medial da amígdala. A concentração plasmática de amônia foi significativamente mais elevada que a do grupo sham e o diagnóstico de cirrose foi confirmado por análise histopatológica. Estes resultados indicam que o modelo de HE induzido por BDL induz efeito ansiogênico possivelmente relacionado à ativação de circuitos mediadores da ansiedade e à hiperamonemia.Universidade Federal de São Paulo (UNIFESP) Departamento de BiociênciasUniversidade de São Paulo Instituto de Ciências Biomédicas Departamento de AnatomiaUNIFESP, Depto. de BiociênciasSciEL

Dietary nitrate and diet quality: An examination of changing dietary intakes within a representative sample of Australian women

Dietary nitrate is increasingly linked to a variety of beneficial health outcomes. Our purpose was to estimate dietary nitrate consumption and identify key dietary changes which have occurred over time within a representative sample of Australian women. Women from the 1946–1951 cohort of the Australian Longitudinal Study on Women’s Health with complete food frequency questionnaire data for both 2001 and 2013 were included for analysis. Dietary nitrate intakes were calculated using key published nitrate databases. Diet quality scores including the Australian Recommended Food Score, the Mediterranean Diet Score and the Nutrient Rich Foods Index were calculated along with food group serves as per the Australian Dietary Guidelines. Wilcoxon matched pairs tests were used to test for change in dietary intakes and Spearman’s correlations were used to examine associations. In our sample of 8161 Australian women, dietary nitrate intakes were on average 65–70 mg/day, and we detected a significant increase in dietary nitrate consumption over time (+6.57 mg/day). Vegetables were the primary source of dietary nitrate (81–83%), in particular lettuce (26%), spinach (14–20%), beetroot (10–11%), and celery (7–8%) contributed primarily to vegetable nitrate intakes. Further, increased dietary nitrate intakes were associated with improved diet quality scores (r = 0.3, p \u3c 0.0001). Although there is emerging evidence indicating that higher habitual dietary nitrate intakes are associated with reduced morbidity and mortality, future work in this area should consider how dietary nitrate within the context of overall diet quality can facilitate health to ensure consistent public health messages are conveyed

Visceral Leishmaniasis in a New York Foxhound Kennel

Although endemic throughout much of the world, autochthonous visceral leishmaniasis has been reported on only 3 previous occasions in North America. After diagnosis of visceral leishmaniasis in 4 foxhounds from a kennel in Dutchess County, New York (index kennel), serum and ethylenediamine-tetraacetic acid (EDTA)-anticoagulated blood were collected from the remaining 108 American or cross-bred foxhounds in the index kennel and from 30 Beagles and Basset Hounds that were periodically housed in the index kennel. Samples were analyzed for antibodies to or DNA of tickborne disease pathogens and Leishmania spp. Most dogs had antibodies to Rickettsia spp., Ehrlichia spp., Babesia spp., or some combination of these pathogens but not to Bartonella vinsonii (berkhoffi). However, DNA of rickettsial, ehrlichial, or babesial agents was detected in only 9 dogs. Visceral leishmaniasis was diagnosed in 46 of 112 (41%) foxhounds from the index kennel but was not diagnosed in any of the Beagles and Basset Hounds. A positive Leishmania status was defined by 1 or more of the following criteria: a Leishmania antibody titeror = 1:64, positive Leishmania polymerase chain reaction (PCR), positive Leishmania culture, or identification of Leishmania amastigotes by cytology or histopathology. The species and zymodeme of Leishmania that infected the foxhounds was determined to be Leishmania infantum MON-1 by isoenzyme electrophoresis. Foxhounds that were18 months of age or that had traveled to the southeastern United States were more likely to be diagnosed with visceral leishmaniasis. Transmission of Leishmania spp. in kennel outbreaks may involve exposure to an insect vector, direct transmission, or vertical transmission

Elimination of the vesicular acetylcholine transporter in the forebrain causes hyperactivity and deficits in spatial memory and long-term potentiation

Basal forebrain cholinergic neurons, which innervate the hippocampus and cortex, have been implicated in many forms of cognitive function. Immunolesion-based methods in animal models have been widely used to study the role of acetylcholine (ACh) neurotransmission in these processes, with variable results. Cholinergic neurons have been shown to release both glutamate and ACh, making it difficult to deduce the specific contribution of each neurotransmitter on cognition when neurons are eliminated. Understanding the precise roles of ACh in learning and memory is critical because drugs that preserve ACh are used as treatment for cognitive deficits. It is therefore important to define which cholinergic-dependent behaviors could be improved pharmacologically. Here we investigate the contributions of forebrain ACh on hippocampal synaptic plasticity and cognitive behavior by selective elimination of the vesicular ACh transporter, which interferes with synaptic storage and release of ACh. We show that elimination of vesicular ACh transporter in the hippocampus results in deficits in long-term potentiation and causes selective deficits in spatial memory. Moreover, decreased cholinergic tone in the forebrain is linked to hyperactivity, without changes in anxiety or depression-related behavior. These data uncover the specific contribution of forebrain cholinergic tone for synaptic plasticity and behavior. Moreover, these experiments define specific cognitive functions that could be targeted by cholinergic replacement therapy

Effect of a self-determination theory-based communication skills training program on physiotherapists' psychological support for their patients with chronic low back pain: a randomized controlled trial

Objective: To examine the effects of communication skills training on physiotherapists' supportive behavior during clinical practice. Design: Randomized trial. Setting: Hospital outpatient physiotherapy clinics. Participants: Physiotherapists (N=24) and patients (N=24) with chronic low back pain. Interventions: Two hospital clinics were randomly assigned to the intervention arm. Physiotherapists (n=12) received 8 hours of communication skills training focused on supporting patients' psychological needs. Physiotherapists (n=12) from 2 other hospital clinics formed a waitlist control arm. Main Outcome Measures: Verbal communication between each physiotherapist and a patient was recorded on an audiotape, and independent, blinded raters used the Health Care Climate Questionnaire to assess physiotherapists' needs-supportive behavior (primary outcome). Results: Independent raters' Health Care Climate Questionnaire scores favored the intervention arm (Cohen's d=2.27; P<.01). Conclusions: Compared with controls, independent ratings demonstrated that physiotherapists who completed the Communication style and exercise compliance in physiotherapy training were found to provide greater support for patients' needs in a single assessed session. Long-term maintenance of this needs-supportive behavior should be examined

An agonistic anti-CD137 antibody disrupts lymphoid follicle structure and T-cell-dependent antibody responses

CD137 is a costimulatory receptor expressed on natural killer cells, T cells, and subsets of dendritic cells. An agonistic monoclonal antibody (mAb) against CD137 has been used to reduce tumor burden or reverse autoimmunity in animal models and clinical trials. Here, we show that mice treated with an agonistic anti-CD137 mAb have reduced numbers of germinal center (GC) B cells and follicular dendritic cells (FDCs) in lymphoid tissues, which impair antibody responses to multiple T-cell-dependent antigens, including infectious virus, viral proteins, and conjugated haptens. These effects are not due to enhanced apoptosis or impaired proliferation of B cells but instead correlate with changes in lymphoid follicle structure and GC B cell dispersal and are mediated by CD137 signaling in CD