The cell surface polysaccharides and membrane protein required for bacteriophage infection of Lactococcus lactis

The bacteriophage receptor of lactococci was found on the cell walls. A carbohydrate analysis of the cell walls from phage-resistant mutants of L. lactis subsp. cremoris KR with reductions in phage binding indicated that a loss of galactose correlated with a loss in binding and infection of all phage tested: kh, 643, 1, c2 and m13. In addition, a loss of rhamnose correlated with a reduction in binding of phages kh and m13. Inhibition studies of phage binding by lectins specific to galactose suggested that phage kh does not bind directly to galactose. Incubation of any of the five phages with 0.5M rhamnose, but not galactose, completely inactivated the phage. Addition of rhamnose to a growing liquid culture infected with all five phages or with phage kh inhibited the infection. This suggested that the receptor of phage for L. lactis subsp. cremoris KR is the rhamnose of the extracellular polysaccharide. In a similar analysis, phage skl was found to require rhamnose and glucose of the extracellular polysaccharide of L. lactis subsp. lactis C2 for binding. The lectin studies suggests that phage ski does not bind directly to glucose. The partial inhibition of phage ski infection when rhamnOse, but not glucose, was added to a liquid culture suggests that phage ski binds directly to the rhamnose. The phage-resistant mutants isolated from superinfections of L. lactis subsp. lactis C2 with phage c2 did not form plaques, but bound normally to phage c2. The sensitivity of these mutants to phage ski was also reduced significantly. In another analysis of mutants isolated from superinfections with phage skl, none formed plaques with either phage c2 or skl, but bound normally to both phages. The mutations affected the cell membrane, as the membrane from wild type, but not from phage-resistant cells, inactivated phage c2. The phage-inactivation activity was eliminated by treatment with a protease, but not a glycosidase. The partially purified phage-inactivating protein was found to have an apparent molecular weight of 350,000 under nondenaturing conditions and an apparent subunit size of 32 kDa. It is proposed that a multimeric complex of the 32 kDa protein is required for phage c2 and skl infection of strain C2

To reach the poor: results from the ISNAR-IFPRI Next Harvest study on genetically modified crops, public research, and policy implications

"Local farming communities throughout the world face productivity constraints, environmental concerns, and diverse nutritional needs. Developing countries address these challenges in a number of ways. One way is public research that produces genetically modified (GM) crops and recognize biotechnology as a part of the solution. To reach these communities, GM crops, after receiving biosafety agreement, must be approved for evaluation under local conditions. However, gaps between approvals in the developed and developing world grow larger, as the process of advancing GM crops in developing countries becomes increasingly difficult. In several countries, only insect resistant cotton has successfully moved from small, confined experimental trials to larger, open trials and to farms. By far, most GM crop approvals have been for commercial products that perform well under tropical conditions. However, complete information on public GM crop research in developing countries has not been assessed. “Will policies and research institutions in the developing world stimulate the safe use of publicly funded GM food crops?” The relatively few GM crops approved from public research, coupled with growing regulatory, biosafety capacity, trade, and political concerns, argue to the contrary. To tackle this issue, we identified and analyzed public research pipelines for GM crops among 16 developing countries and transition economies. Respondents reported 209 genetic transformation events for 46 different crops at the time when the survey was conducted. The pipelines demonstrate scientific progress among publicly funded crop research institutes in participating countries. Information and findings are presented for GM crops nearing final stages of selection. Additional details are provided for the types of genes and traits used, the breadth of genetic resources documented, implications for regulation, and the type of research partnerships employed. Regulations, GM crop approvals, choice of transgene, and policy implications are discussed as they affect this research. Based on these findings, recommendations are presented that would help sustain and increase efficiency of publicly supported research while meeting biosafety requirements. To do so, the study examines results concerning investments and choices made in research, capacity, and policy development for biotechnology. These indicate the risk and potential for GM technologies in developing countries. Policy makers, those funding biotechnology, and other stakeholders can use this information to prioritize investments, consider product advancement, and assess relative magnitude of potential risks, and benefits." Authors' Abstract

Rapid Analysis of Listeria monocytogenes Cell Wall Teichoic Acid Carbohydrates by ESI-MS/MS

We report the application of electrospray ionization (ESI) mass spectrometry for compositional characterization of wall teichoic acids (WTA), a major component of Gram-positive bacterial cell walls. Tandem mass spectrometry (ESI-MS/MS) of purified and chemically hydrolyzed monomeric WTA components provided sufficient information to identify WTA monomers and their specific carbohydrate constituents. A lithium matrix was used for ionization of uncharged WTA monomers, and successfully applied to analyze the WTA molecules of four Listeria strains differing in carbohydrate substitution on a conserved polyribitol-phosphate backbone structure. Carbohydrate residues such as N-acetylglucosamine or rhamnose linked to the WTA could directly be identified by ESI-MS/MS, circumventing the need for quantitative analysis by gas chromatography. The presence of a terminal N-acetylglucosamine residue tethered to the ribitol was confirmed using fluorescently labeled wheat-germ agglutinin. In conclusion, the mass spectrometry method described here will greatly facilitate compositional analysis and characterization of teichoic acids and similar macromolecules from diverse bacterial species, and represents a significant advance in the identification of serovar-specific carbohydrates and sugar molecules on bacteria

Laboratorial approach in the diagnosis of food allergy

OBJCTIVE: Review the available laboratory tests used to assist in the diagnosis of IgE-mediated and non-IgE-mediated food allergy. DATA SOURCES: Papers in English and Portuguese published in PubMed and Embase, in the last ten years. Terms searched were food allergy, diagnose and laboratory, isolated and/or associated. DATA SYNTHESIS: The diagnostic approach to food allergy reactions includes a good medical history, laboratory studies, elimination diets and blinded food challenges. More recently, the use of a quantitative measurement of food-specific IgE antibodies has been shown to be more predictive of symptomatic IgE-mediated food allergy. Food-specific IgE serum levels exceeding the diagnostic values indicate that the patient is greater than 95% likely to experience an allergic reaction if he/she ingests the specific food. Such decision point values have been defined just for some foods and inconsistent results were obtained when allergy to the same food was studied in different centers. Food challenges, in particular the double-blind placebo-controlled food challenge (DBPCFC), represent the most reliable way to establish or rule out food hypersensitivity. CONCLUSIONS: A number of recent developments are improving the predictive value of some laboratory tests for the diagnosis of food allergies. However, to date, no in-vitro or in-vivo test shows full correlation with clinical food allergy and the DBPCFC remains the gold standard for the definitive diagnosis of specific food allergies. There is an urgent need for new and fundamentally improved diagnostic approaches, which must be validated in patients with food allergy confirmed by a positive DBPCFC.OBJETIVO: Revisar os exames laboratoriais disponíveis utilizados no diagnóstico da alergia alimentar mediada ou não por IgE. FONTES DE DADOS: Artigos publicados em base de dados PubMed e Embase (língua inglesa e portuguesa) nos últimos dez anos. As palavras-chave utilizadas como fonte de busca foram alergia alimentar, diagnóstico e laboratório, isolados e/ou associados. SÍNTESE DOS DADOS: A abordagem diagnóstica das reações alérgicas a alimentos inclui história clínica completa, estudos laboratoriais, dietas de eliminação e desencadeamentos cegos com alimentos. Recentemente, a medida quantitativa de anticorpos IgE específicos a alimentos tem mostrado ser mais preditiva de alergia alimentar sintomática mediada por IgE. Níveis séricos de IgE específica a alimento que excedam os valores diagnósticos indicam que o paciente tem chance maior que 95% de apresentar uma reação alérgica se ingerir o alimento em questão. Estes valores de decisão foram definidos para alguns alimentos e resultados inconsistentes são obtidos ao se estudar diferentes populações. Os desencadeamentos com alimento, especialmente o duplo-cego controlado por placebo (DADCCP), representa a maneira mais confiável de estabelecer ou descartar o diagnóstico de hipersensibilidade alimentar. CONCLUSÕES: Número crescente de aquisições tem melhorado o valor preditivo de alguns testes laboratoriais empregados no diagnóstico de alergias alimentares. Entretanto, até hoje, não há teste in vitro ou in vivo que mostre correlação completa com a clínica da alergia alimentar. O DADCCP continua sendo o padrão-ouro no diagnóstico definitivo de alergia alimentar específica. São necessárias, urgentemente, novas abordagens diagnósticas válidadas em pacientes com alergia alimentar confirmada por DADCCP positivo.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PediatriaUNIFESP-EPM Departamento de PediatriaUniversidade de São Paulo Faculdade de Medicina Departamento de PediatriaUniversidade Federal da Bahia Departamento de PediatriaUNIFESP-EPMUniversidade Federal do Paraná Departamento de PediatriaUNIFESP, EPM, Depto. de PediatriaUNIFESP, EPM Depto. de PediatriaUNIFESP, EPMSciEL

Contribution of scaling up nutrition Academic Platforms to nutrition capacity strengthening in Africa: local efforts, continental prospects and challenges

Addressing contemporary nutrition problems often require application of knowledge from multiple disciplines. The scaling up nutrition (SUN) movement harnesses multiple sectors for effective global and in-country planning and implementation. Although the role of knowl- edge networks (academia and research institutions) is recognised, the how of engaging knowl- edge networks in the current SUN architecture is only now becoming apparent. For relevant sectors to play their roles effectively, observed capacity gaps, particularly in developing coun- try settings, need to be addressed. The present paper presents the work being undertaken by the Ghana SUN Academic Platform, a local knowledge network, towards strengthening nutrition capacity in Ghana. The Platform presently provides technical support, evidence and capacity towards scaling up effective nutrition interventions in Ghana and beyond. The data presented draws heavily on the observations and collective experiences of the authors in practice, com- plemented by a review of relevant literature. The ultimate goal of the AP is to build capacity of professionals from nutrition and cognate sectors (including planning, agriculture, health, economics, research and academia). This is an essential ingredient for effective and durable SUN efforts. The paper recognises that both disciplinary and interdisciplinary capacity is required for effective SUN efforts in Africa, and offers an approach that utilises cross-sector/inter-professional, peer-learning and experiential learning initiatives

Risk and safety requirements for diagnostic and therapeutic procedures in allergology : World Allergy Organization Statement

Peer reviewe