The F420H2 dehydrogenase from Methanosarcina mazei is a Redox-driven proton pump closely related to NADH dehydrogenases

The F(420)H(2) dehydrogenase is part of the energy conserving electron transport system of the methanogenic archaeon Methanosarcina mazei G?1. Here it is shown that cofactor F(420)H(2)-dependent reduction of 2-hydroxyphenazine as catalyzed by the membrane-bound enzyme is coupled to proton translocation across the cytoplasmic membrane, exhibiting a stoichiometry of 0.9 H(+) translocated per two electrons transferred. The electrochemical proton gradient thereby generated was shown to drive ATP synthesis from ADP + P(i). The gene cluster encoding the F(420)H(2) dehydrogenase of M. mazei G?1 comprises 12 genes that are referred to as fpoA, B, C, D, H, I, J, K, L, M, N, and O. Analysis of the deduced amino acid sequences revealed that the enzyme is closely related to proton translocating NADH dehydrogenases of respiratory chains from bacteria (NDH-1) and eukarya (complex I). Like the NADH-dependent enzymes, the F(420)H(2) dehydrogenase is composed of three subcomplexes. The gene products FpoA, H, J, K, L, M, and N are highly hydrophobic and are homologous to subunits that form the membrane integral module of NDH-1. FpoB, C, D, and I have their counterparts in the amphipathic membrane-associated module of NDH-1. Homologues to the hydrophilic NADH-oxidizing input module are not present in M. mazei G?1. Instead, the gene product FpoF may be responsible for F(420)H(2) oxidation and may function as the electron input part. Thus, the F(420)H(2) dehydrogenase from M. mazei G?1 resembles eukaryotic and bacterial proton translocating NADH dehydrogenases in many ways. The enzyme from the methanogenic archaeon functions as a NDH-1/complex I homologue and is equipped with an alternative electron input unit for the oxidation of reduced cofactor F(420) and a modified output module adopted to the reduction of methanophenazine.     

Isotope evidence for the intensive use of marine foods by Late Upper Palaeolithic humans

We report here on direct evidence for the intensive consumption of marine foods by anatomically modern humans at approximately 12,000 years ago. We undertook isotopic analysis of bone collagen from three humans, dating to the late Palaeolithic, from the site of Kendrick's Cave in North Wales, UK. The isotopic measurements of their bone collagen indicated that ca. 30% of their dietary protein was from marine sources, which we interpret as likely being high trophic level marine organisms such as marine mammals. This indicates that towards the end of the Pleistocene modern humans were pursuing a hunting strategy that incorporated both marine and terrestrial mammals. This is the first occurrence of the intensive use of marine resources, specifically marine mammals, that becomes even more pronounced in the subsequent Mesolithic period.     

Effects of selective COX-2 and 5-LOX inhibition on prostaglandin and leukotriene synthesis in ductal pancreatic cancer in Syrian hamster

Selective inhibition of eicosanoid synthesis seems to decrease carcinogenesis, however, the effect on liver metastasis in pancreatic cancer is still unknown. Ductal pancreatic adenocarcinoma was chemically induced by weekly injection of N-nitrosobis-2-oxopropylamine (BOP) in Syrian hamster. Animals received selective inhibition of cyclooxygenase-2 (Celebrex) and 5-lipoxygenase (Zyflo). In week 33, hamsters were sacrificed and incidence of pancreatic carcinomas as well as liver metastases were examined. Furthermore, size and number of liver metastases per animal were determined and concentration of PGF1alpha, PGE2 and leukotrienes was measured in hepatic and pancreatic tissue. Combined therapy (Celebrex+Zyflo) significantly decreased incidence, number and size of liver metastases. Furthermore extra- and intrametastatic concentration of PGE2 was reduced by this treatment in hepatic tissue. Single Cox-2-inhibition (Celebrex) decreased intrametastatic hepatic PGF1alpha and PGE2 concentration while PGF1alpha concentration was reduced in non-metastatic liver (nml). Moreover 5-LOX-inhibition (Zyflo) decreased intrametastatic PGE2 concentration as well as PGF1alpha and PGE2 in nml. In pancreatic carcinomas highest LT-concentration was found after combined treatment and this therapy group was the only one revealing a significantly higher amount of LTs in carcinomas compared to tumour-free tissue. Hepatic LT-concentration was significantly lower in the control groups than in nml of the tumour groups. Combination of Cox-2-inhibition and 5-Lox-inhibition might be a suitable adjuvant therapy to prevent liver metastasis in human ductal pancreatic adenocarcinoma.     

Yersinia enterocolitica invasin protein triggers IL-8 production in epithelial cells via activation of Rel p65-p65 homodimers.

Enteropathogenic YERSINIA: bacteria trigger the production of the proinflammatory chemokine IL-8, an important chemokine for the recruitment of polymorphonuclear leukocytes (PMN). YERSINIA: is resistant to phagocytosis by PMN, and the recruitment of these cells is thought to be part of a pathogenic strategy of YERSINIA: to establish infection by allowing the pathogen to gain access to, and disseminate within, host tissue. We report here that YERSINIA: expressing the outer membrane protein invasin triggers IL-8 production in epithelial cells. The 195 carboxyl-terminal amino acids of invasin when linked to latex beads are sufficient to trigger IL-8 production. By means of IL-8 promoter reporter gene assays and electrophoretic mobility shift assay experiments, the minimal optimal region of the IL-8 promoter responsive to invasin was identified and invasin-responsive control elements were characterized. Invasin-induced activation of the IL-8 promoter was found to be mediated through a previously identified NF-kappaB element. This NF-kappaB binding site preferentially binds Rel p65-p65 homodimers as well as some p50-p65 heterodimers in response to stimulation by invasin. Invasin-induced NF-kappaB activation correlated with degradation of IkappaBalpha and the inhibition of NF-kappaB by specific inhibitors of IkappaB activation blocked invasin-induced IL-8 secretion. Invasin-triggered IL-8 production does not depend on invasin-triggered uptake of bacteria, and is independent of a functional PI3-kinase. This report is the first to demonstrate the molecular basis of IL-8 production triggered by enteropathogenic bacteria. Together, these data elucidate the possible early pathomechanisms operating in YERSINIA: infection and may have implications for the design of novel therapeutics directed against this enteropathogen.     

Synergistic Effects of Cu(II) and Dimethylammonium 2,4-Dichlorophenoxyacetate (U46 D Fluid) on PM2 DNA and Mechanism of Dna Damage

Dimethylammonium 2,4-dichlorophenoxyacetate (2,4-D · DMA) induced strand breaks in PM2 DNA when incubated with CuCl₂, whereas 2,4-D · DMA alone or CuCl₂ alone did not show any or only a negligible effect. The formation of single strand breaks increased linearly with time and concentration of 2,4-D · DMA. Neocuproine, a specific Cu(I) chelator totally prevented strand break formation. So did catalase (up to 100mM 2,4-D · DMA), but DMSO had only a small protective effect. 2,4-Dichlorophenol, CO₂ and formaldehyde were detected as reaction products of 2,4-D and CuCl₂. From these results a redox reaction of Cu(II) and 2,4-D is proposed, which could explain the DNA damaging properties of CuCl₂/2,4-D · DMA.     

B cells in autoimmunity

B-cell development is tightly regulated, including the induction of B-cell memory and antibody-secreting plasmablasts and plasma cells. In the last decade, we have expanded our understanding of effector functions of B cells as well as their roles in human autoimmune diseases. The current review addresses the role of certain stages of B-cell development as well as plasmablasts/plasma cells in immune regulation under normal and autoimmune conditions with particular emphasis on systemic lupus erythematosus. Based on preclinical and clinical data, B cells have emerged increasingly as both effector cells as well as cells with immunoregulatory potential.     

Synthetic Long Peptide Influenza Vaccine Containing Conserved T and B Cell Epitopes Reduces Viral Load in Lungs of Mice and Ferrets

Currently licensed influenza vaccines mainly induce antibodies against highly variable epitopes. Due to antigenic drift, protection is subtype or strain-specific and regular vaccine updates are required. In case of antigenic shifts, which have caused several pandemics in the past, completely new vaccines need to be developed. We set out to develop a vaccine that provides protection against a broad range of influenza viruses. Therefore, highly conserved parts of the influenza A virus (IAV) were selected of which we constructed antibody and T cell inducing peptide-based vaccines. The B epitope vaccine consists of the highly conserved HA2 fusion peptide and M2e peptide coupled to a CD4 helper epitope. The T epitope vaccine comprises 25 overlapping synthetic long peptides of 26-34 amino acids, thereby avoiding restriction for a certain MHC haplotype. These peptides are derived from nucleoprotein (NP), polymerase basic protein 1 (PB1) and matrix protein 1 (M1). C57BL/6 mice, BALB/c mice, and ferrets were vaccinated with the B epitopes, 25 SLP or a combination of both. Vaccine-specific antibodies were detected in sera of mice and ferrets and vaccine-specific cellular responses were measured in mice. Following challenge, both mice and ferrets showed a reduction of virus titers in the lungs in response to vaccination. Summarizing, a peptide-based vaccine directed against conserved parts of influenza virus containing B and T cell epitopes shows promising results for further development. Such a vaccine may reduce disease burden and virus transmission during pandemic outbreaks.     

Effect of Comprehensive Oncogenetics Training Interventions for General Practitioners,Evaluated at Multiple Performance Levels

General practitioners (GPs) are increasingly called upon to identify patients at risk for hereditary cancers, and their genetic competencies need to be enhanced. This article gives an overview of a research project on how to build effective educational modules on genetics, assessed by randomized controlled trials (RCTs), reflecting the prioritized educational needs of primary care physicians. It also reports on an ongoing study to investigate long-term increase in genetic consultation skills (1-year follow-up) and interest in and satisfaction with a supportive website on genetics among GPs. Three oncogenetics modules were developed: an online Continuing Professional Development (G-eCPD) module, a live genetic CPD module, and a “GP and genetics” website (huisartsengenetica.nl) providing further genetics information applicable in daily practice. Three assessments to evaluate the effectiveness (1-year follow-up) of the oncogenetic modules were designed: 1.An online questionnaire on self-reported genetic competencies and changes in referral behaviour, 2.Referral rates from GPs to clinical genetics centres and 3.Satisfaction questionnaire and visitor count analytics of supportive genetics website. The setting was Primary care in the Netherlands and three groups of study participants were included in the reported studies:. Assessment 1. 168 GPs responded to an email invitation and were randomly assigned to an intervention or control group, evaluating the G-eCPD module (n = 80) or the live module (n = 88). Assessment 2. Referral rates by GPs were requested from the clinical genetics centres, in the northern and southern parts of the Netherlands (Amsterdam and Maastricht), for the two years before (2010 [n = 2510] and 2011 [n = 2940]) and the year after (2012 [n = 2875]) launch of the oncogenetics CPD modules and the website. Assessment 3. Participants of the website evaluation were all recruited online. When they visited the website during the month of February 2013, a pop-up invitation came up. Of the 1350 unique visitors that month, only 38 completed the online questionnaire. Main outcomes measure showed long-term (self-reported) genetic consultation skills (i.e. increased genetics awareness and referrals to clinical genetics centres) among GPs who participated in the oncogenetic training course, and interest in and satisfaction with the supportive website. 42 GPs (52%) who previously participated in the G-eCPD evaluation study and 50 GPs (57%) who participated in the live training programme responded to the online questionnaire on long-term effects of educational outcome. Previous RCTs showed that the genetics CPD modules achieved sustained improvement of oncogenetic knowledge and consultation skills (3-months follow-up). Participants of these RCTs reported being more aware of genetic problems long term; this was reported by 29 GPs (69%) and 46 GPs (92%) participating in the G-eCPD and live module evaluation studies, respectively (Chisquare test, p<0.005). One year later, 68% of the respondents attending the live training reported that they more frequently referred patients to the clinical genetics centres, compared to 29% of those who attended the online oncogenetics training (Chisquare test, p<0.0005). However, the clinical genetics centres reported no significant change in referral numbers one year after the training. Website visitor numbers increased, as did satisfaction, reflected in a 7.7 and 8.1 (out of 10) global rating of the website (by G-eCPD and live module participants, respectively). The page most often consulted was “family tree drawing”. Self-perceived genetic consultation skills increased long-term and GPs were interested in and satisfied with the supportive website. Further studies are necessary to see whether the oncogenetics CPD modules result in more efficient referral. The results presented suggest we have provided a flexible and effective framework to meet the need for effective educational programmes for non-geneticist healthcare providers, enabling improvement of genetic medical care.