A highly specific tool for identification of Xanthomonas vasicola pv. musacearum based on five Xvm-specific coding sequences

This is the final version. Available on open access from Elsevier via the DOI in this recordXanthomonas vasicola pv. musacearum (Xvm) is a bacterial pathogen responsible for the economically important Xanthomonas wilt disease on banana and enset crops in Sub-Saharan Africa. Given that the symptoms are similar to those of other diseases, molecular diagnosis is essential to unambiguously identify this pathogen and distinguish it from closely related strains not pathogenic on these hosts. Currently, Xvm identification is based on polymerase chain reaction (PCR) with GspDm primers, targeting the gene encoding general secretory protein D. Experimental results and examination of genomic sequences revealed poor specificity of the GspDm PCR. Here, we present and validate five new Xvm-specific primers amplifying only Xvm strains.Agropolis Fondatio

Influence of altitude as a proxy for temperature on key Musa pests and diseases in watershed areas of Burundi and Rwanda

Open Access ArticlePests and diseases are key biotic constraints limiting banana production among smallholder farmers in Eastern and Central Africa. Climate changemay favour pest and disease development and further exacerbate the vulnerability of smallholder farming systems to biotic constraints. Information on effects of climate change on pests and pathogens of banana is required by policy makers and researchers in designing control strategies and adaptation plans. Since altitude is inversely related to temperature, this study used the occurrence of key banana pests and diseases along an altitude gradient as a proxy for the potential impact of changes in temperature associated with global warming on pests and diseases. We assessed the occurrence of banana pests and diseases in 93 banana fields across three altitude ranges in Burundi and 99 fields distributed in two altitude ranges in Rwanda watersheds. Incidence and prevalence of Banana Bunchy Top Disease (BBTD) and Fusarium wilt (FW) was significantly associated with temperature and altitude in Burundi, revealing that increasing temperatures may lead to upward movement of banana diseases. No significant associations with temperature and altitude were observed for weevils, nematodes and Xanthomonas wilt of banana (BXW). Data collected in this study provides a baseline to verify and guide modelling work to predict future pest and disease distribution according to climate change scenarios. Such information is useful in informing policy makers and designing appropriate management strategies

Regulation of Notch signaling by Drosophila heparan sulfate 3-O sulfotransferase

Heparan sulfate (HS) regulates the activity of various ligands and is involved in molecular recognition events on the cell surface and in the extracellular matrix. Specific binding of HS to different ligand proteins depends on the sulfation pattern of HS. For example, the interaction between antithrombin and a particular 3-O sulfated HS motif is thought to modulate blood coagulation. However, a recent study of mice defective for this modification suggested that 3-O sulfation plays other biological roles. Here, we show that Drosophila melanogaster HS 3-O sulfotransferase-b (Hs3st-B), which catalyzes HS 3-O sulfation, is a novel component of the Notch pathway. Reduction of Hs3st-B function by transgenic RNA interference compromised Notch signaling, producing neurogenic phenotypes. We also show that levels of Notch protein on the cell surface were markedly decreased by loss of Hs3st-B. These findings suggest that Hs3st-B is involved in Notch signaling by affecting stability or intracellular trafficking of Notch protein

New Approach for M-Cell-Specific Molecules Screening by Comprehensive Transcriptome Analysis

A minor population of M cells within the follicle-associated epithelium (FAE) of intestinal Peyer's patches (PPs) serves as a major portal for entry of exogenous antigens. Characterization of the mammalian M cells, including identification of M-cell surface molecules used for bacterial uptake, has been hampered by their relative rarity. In contrast, M cells constitute virtually all of the FAE cells in the avian bursa of Fabricius. We therefore performed comparative gene expression profiling of chicken and murine FAE to identify commonly expressed genes by M cells in both species. The comprehensive transcriptome analysis revealed that 28 genes were commonly up-regulated in FAE from both species. In situ hybridization revealed that annexin A10 (Anxa10) mRNA was scattered in FAE, and co-localized with Ulex europaeus agglutinin-1 binding to M cells. Whole-mount immunostaining also revealed that cellular prion protein (PrPC) was expressed on the luminal side of the apical plasma membrane of M cells, and co-localized with grycoprotein 2 that recognizes only M cells in murine PP. Our findings identify new M-cell-specific molecules through using comprehensive transcriptome analysis. These conserved molecules in M cells of mice and chickens may play essential roles in M-cell function and/or differentiation

The effectiveness of public health interventions to reduce the health impact of climate change:a systematic review of systematic reviews

Climate change is likely to be one of the most important threats to public health in the coming years. Yet despite the large number of papers considering the health impact of climate change, few have considered what public health interventions may be of most value in reducing the disease burden. We aimed to evaluate the effectiveness of public health interventions to reduce the disease burden of high priority climate sensitive diseases

The functional maturation of M cells is dramatically reduced in the Peyer's patches of aged mice

The transcytosis of antigens across the follicle-associated epithelium (FAE) of Peyer's patches by microfold cells (M cells) is important for the induction of efficient immune responses to mucosal antigens. The mucosal immune response is compromised by ageing, but effects on M cells were unknown. We show that M-cell density in the FAE of aged mice was dramatically reduced. As a consequence, aged Peyer's patches were significantly deficient in their ability to transcytose particulate lumenal antigen across the FAE. Ageing specifically impaired the expression of Spi-B and the downstream functional maturation of M cells. Ageing also dramatically impaired C-C motif chemokine ligand 20 expression by the FAE. As a consequence, fewer B cells were attracted towards the FAE, potentially reducing their ability to promote M-cell maturation. Our study demonstrates that ageing dramatically impedes the functional maturation of M cells, revealing an important ageing-related defect in the mucosal immune system's ability to sample lumenal antigens

Competing charge transfer pathways at the photosystem II-electrode interface.

The integration of the water-oxidation enzyme photosystem II (PSII) into electrodes allows the electrons extracted from water oxidation to be harnessed for enzyme characterization and to drive novel endergonic reactions. However, PSII continues to underperform in integrated photoelectrochemical systems despite extensive optimization efforts. Here we carried out protein-film photoelectrochemistry using spinach and Thermosynechococcus elongatus PSII, and we identified a competing charge transfer pathway at the enzyme-electrode interface that short-circuits the known water-oxidation pathway. This undesirable pathway occurs as a result of photo-induced O2 reduction occurring at the chlorophyll pigments and is promoted by the embedment of PSII in an electron-conducting fullerene matrix, a common strategy for enzyme immobilization. Anaerobicity helps to recover the PSII photoresponse and unmasks the onset potentials relating to the QA/QB charge transfer process. These findings impart a fuller understanding of the charge transfer pathways within PSII and at photosystem-electrode interfaces, which will lead to more rational design of pigment-containing photoelectrodes in general.This work was supported by the U.K. Engineering and Physical Sciences Research Council (EP/H00338X/2 to E. Reisner), the U.K. Biology and Biotechnological Sciences Research Council (BB/K010220/1 to E. Reisner), a Marie Curie International Incoming Fellowship (PIIF-GA-2012-328085 RPSII to J.J.Z.). N.P. was supported by the Winton Fund for the Physics of Sustainability. E. Romero. and R.v.G. were supported by the VU University Amsterdam, the Laserlab-Europe Consortium, the TOP grant (700.58.305) from the Foundation of Chemical Sciences part of NWO, the Advanced Investigator grant (267333, PHOTPROT) from the European Research Council, and the EU FP7 project PAPETS (GA 323901). R.v.G. gratefully acknowledges his `Academy Professor' grant from the Royal Netherlands Academy of Arts and Sciences (KNAW). We would also like to thank Miss Katharina Brinkert and Prof A. William Rutherford for a sample of T. elongatus PSII, and H. v. Roon for preparation of the spinach PSII samples

M cell-depletion blocks oral prion disease pathogenesis

Many prion diseases are orally acquired. Our data show that after oral exposure, early prion replication upon follicular dendritic cells (FDC) in Peyer's patches is obligatory for the efficient spread of disease to the brain (termed neuroinvasion). For prions to replicate on FDC within Peyer's patches after ingestion of a contaminated meal, they must first cross the gut epithelium. However, the mechanism through which prions are conveyed into Peyer's patches is uncertain. Within the follicle-associated epithelium overlying Peyer's patches are microfold cells (M cells), unique epithelial cells specialized for the transcytosis of particles. We show that following M cell-depletion, early prion accumulation upon FDC in Peyer's patches is blocked. Furthermore, in the absence of M cells at the time of oral exposure, neuroinvasion and disease development are likewise blocked. These data suggest M cells are important sites of prion uptake from the gut lumen into Peyer's patches