141 research outputs found

    Editorial: Celebrating Microbial Diversity: The Many Cell Cycles of Eukaryotic Microbes.

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    Editorial on the Research Topic Celebrating Microbial Diversity: The Many Cell Cycles of Eukaryotic MicrobesCM: ERC research grant ‘Plasmocycle’. ZL: NIH R01 grant AI101437. MB: Swiss National Science Foundation 31003A_179321

    Occurrence and specificity of glucose oxidase (E.C: 1.1.3.4) in botrytized sweet white wine. Comparison with laccase (E.C: 1.10.3.2), considered as the main responsible factor for oxidation in this type of wine

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    Two types of oxidizing enzymes are present in botrytized white grapes and wines: laccase (PPO) and glucose oxidase (GOX). The evolution of these two enzymes is similar both during the over-ripening of grapes and during wine making. Yet, PPO is severely inhibited by the addition of SO2 following the alcoholic fermentation, and shows a marked instability in both the must and wine environments. GOX, however, remains free and active in solution and helps develop the main characteristics of the wine. In particular, as is to be expected from its activity, GOX oxidizes tartaric acid, ethanol and glycerol, the major components of must and wine, respectively to glyoxylic acid, acetaldehyde and glyceraldehyde. And then, by nucleophilic additions under acidic conditions, these products react with catechins and proanthocyanidins to form several new compounds, some of which appear in a colored form. These reactions can have an impact on the visual quality of the wine.

    A Communal Bacterial Adhesin Anchors Biofilm and Bystander Cells to Surfaces

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    While the exopolysaccharide component of the biofilm matrix has been intensively studied, much less is known about matrix-associated proteins. To better understand the role of these proteins, we undertook a proteomic analysis of the V. cholerae biofilm matrix. Here we show that the two matrix-associated proteins, Bap1 and RbmA, perform distinct roles in the biofilm matrix. RbmA strengthens intercellular attachments. In contrast, Bap1 is concentrated on surfaces where it serves to anchor the biofilm and recruit cells not yet committed to the sessile lifestyle. This is the first example of a biofilm-derived, communally synthesized conditioning film that stabilizes the association of multilayer biofilms with a surface and facilitates recruitment of planktonic bystanders to the substratum. These studies define a novel paradigm for spatial and functional differentiation of proteins in the biofilm matrix and provide evidence for bacterial cooperation in maintenance and expansion of the multilayer biofilm

    Potential for maternally administered vaccine for infant group B streptococcus

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    BACKGROUND : Natural history studies have correlated serotype-specific anti–capsular polysaccharide (CPS) IgG in newborns with a reduced risk of group B streptococcal disease. A hexavalent CPS–cross-reactive material 197 glycoconjugate vaccine (GBS6) is being developed as a maternal vaccine to prevent invasive group B streptococcus in young infants. METHODS : In an ongoing phase 2, placebo-controlled trial involving pregnant women, we assessed the safety and immunogenicity of a single dose of various GBS6 formulations and analyzed maternally transferred anti-CPS antibodies. In a parallel seroepidemiologic study that was conducted in the same population, we assessed serotype-specific anti-CPS IgG concentrations that were associated with a reduced risk of invasive disease among newborns through 89 days of age to define putative protective thresholds. RESULTS : Naturally acquired anti-CPS IgG concentrations were associated with a reduced risk of disease among infants in the seroepidemiologic study. IgG thresholds that were determined to be associated with 75 to 95% reductions in the risk of disease were 0.184 to 0.827 μg per milliliter. No GBS6-associated safety signals were observed among the mothers or infants. The incidence of adverse events and of serious adverse events were similar across the trial groups for both mothers and infants; more local reactions were observed in the groups that received GBS6 containing aluminum phosphate. Among the infants, the most common serious adverse events were minor congenital anomalies (umbilical hernia and congenital dermal melanocytosis). GBS6 induced maternal antibody responses to all serotypes, with maternal-to-infant antibody ratios of approximately 0.4 to 1.3, depending on the dose. The percentage of infants with anti-CPS IgG concentrations above 0.184 μg per milliliter varied according to serotype and formulation, with 57 to 97% of the infants having a seroresponse to the most immunogenic formulation. CONCLUSIONS : GBS6 elicited anti-CPS antibodies against group B streptococcus in pregnant women that were transferred to infants at levels associated with a reduced risk of invasive group B streptococcal disease.Pfizer and the Bill and Melinda Gates Foundation.http://www.nejm.orghj2024Medical MicrobiologySDG-03:Good heatlh and well-bein

    Lipid components of olive oil from Tunisian cv. Sayali: characterization and authenticity

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    The analysis of the total lipid fraction from the Sayali variety of olive oil was accomplished in the present investigation. Glyceridic, unsaponifiable and flavour fractions of the oil were isolated and identified using several analytical methods. Chromatographic techniques have proven to be suitable for these determinations, especially capillary gas chromatography. Gas chromatography coupled to mass spectrometry was successfully used to identify sterols, triterpenes alcohols, 4-monomethylsterols, aliphatic alcohols and aroma compounds in our samples. Furthermore, solid phase microextraction was used to isolate volatiles from the total lipid fraction. Results from the quantitative characterization of Sayali olive oil showed that oleic acid (77.4%) and triolein (47.4%) were the dominant glyceridic components. However, the main compounds of the unsaponifiable fraction were b-sitosterol (147.5mg/100 g oil), 24-methylene cycloartenol (146.4mg/100 g oil) and hexacosanol (49.3 mg/100 g oil). Moreover, results showed that the aldehydic compounds were the major flavours present in Sayali olive oi

    Wine economy in Picton territory (IInd century BC – Ist century AD) 2. Archaeometrical study of content

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    International audienceIn Picton territory, in the western center of Gaul, the existence of local productions of amphorae have been highlighted by several studies (Durquety et al., 2012; Lemaître, 2012). Local workshops copied the forms of imported amphorae produced in the north of Spain (Pascual 1 and Dressel 2 – 4), or in the Narbonnaise province (Gauloise 4 and 5) (Durquety et al., 2012b). To determine for what purpose these amphorae were manufactured in Picton territory, we undertook the chemical study of the organic residues that were preserved in the vessels. After extraction, these residues can be characterized by mass spectrometry coupled with gas phase chromatography (GCMS). This technique enables the analysis of a wide range of compounds, in particular coming from grapes and wine, such as tartaric, malic, fumaric, succinic acids. Alongside, it can allow the determination of red wine markers (tannins, anthocyanins), and even permit to obtain data on their conservation via the detection of resins. As part of this research, we used a technique developed in the 1960s, pyrolysis, to study organic macromolecules that cannot be directly analyzed by GCMS due to their low volatility. With pyrolysis, the extraction step, which is by definition restrictive since the chemical composition of the residues has to be known to choose the extraction solvent, can be avoided. The analytical method that we developed was applied on amphorae discovered in production sites (Gourgé) that were never used. First, to identify the observable molecules by pyrolysis with GCMS, amphorae shards were soaked in a wine of known composition. Then, archeological residues from amphorae discovered in Limonum were analyzed

    Taller Internacional sobre Modernización de la Organización Campesina

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    75 páginasEl taller analiza las experiencias de modernización de las organizaciones campesinas de otros países, con el fin de identificar alternativas y posibilidades que conduzcan a un fortalecimiento de las organizaciones de base, a su mayor autonomía e independencia, y a su modernización

    The Phosphoenolpyruvate Phosphotransferase System Regulates Vibrio cholerae Biofilm Formation through Multiple Independent Pathwaysâ–¿

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    The bacterial phosphoenolpyruvate phosphotransferase system (PTS) is a highly conserved phosphotransfer cascade that participates in the transport and phosphorylation of selected carbohydrates and modulates many cellular functions in response to carbohydrate availability. It plays a role in the virulence of many bacterial pathogens. Components of the carbohydrate-specific PTS include the general cytoplasmic components enzyme I (EI) and histidine protein (HPr), the sugar-specific cytoplasmic components enzymes IIA (EIIA) and IIB (EIIB), and the sugar-specific membrane-associated multisubunit components enzymes IIC (EIIC) and IID (EIID). Many bacterial genomes also encode a parallel PTS pathway that includes the EI homolog EINtr, the HPr homolog NPr, and the EIIA homolog EIIANtr. This pathway is thought to be nitrogen specific because of the proximity of the genes encoding this pathway to the genes encoding the nitrogen-specific σ factor σ54. We previously reported that phosphorylation of HPr and FPr by EI represses Vibrio cholerae biofilm formation in minimal medium supplemented with glucose or pyruvate. Here we report two additional PTS-based biofilm regulatory pathways that are active in LB broth but not in minimal medium. These pathways involve the glucose-specific enzyme EIIA (EIIAGlc) and two nitrogen-specific EIIA homologs, EIIANtr1 and EIIANtr2. The presence of multiple, independent biofilm regulatory circuits in the PTS supports the hypothesis that the PTS and PTS-dependent substrates have a central role in sensing environments suitable for a surface-associated existence
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