Copper-deficiency in Brassica napus induces copper remobilization, molybdenum accumulation and modification of the expression of chloroplastic proteins

During the last 40 years, crop breeding has strongly increased yields but has had adverse effects on the content of micronutrients, such as Fe, Mg, Zn and Cu, in edible products despite their sufficient supply in most soils. This suggests that micronutrient remobilization to edible tissues has been negatively selected. As a consequence, the aim of this work was to quantify the remobilization of Cu in leaves of Brassica napus L. during Cu deficiency and to identify the main metabolic processes that were affected so that improvements can be achieved in the future. While Cu deficiency reduced oilseed rape growth by less than 19% compared to control plants, Cu content in old leaves decreased by 61.4%, thus demonstrating a remobilization process between leaves. Cu deficiency also triggered an increase in Cu transporter expression in roots (COPT2) and leaves (HMA1), and more surprisingly, the induction of the MOT1 gene encoding a molybdenum transporter associated with a strong increase in molybdenum (Mo) uptake. Proteomic analysis of leaves revealed 33 proteins differentially regulated by Cu deficiency, among which more than half were located in chloroplasts. Eleven differentially expressed proteins are known to require Cu for their synthesis and/or activity. Enzymes that were located directly upstream or downstream of Cu-dependent enzymes were also differentially expressed

The role of released ATP in killing Candida albicans and other extracellular microbial pathogens by cationic peptides

A unifying theme common to the action of many cationic peptides that display lethal activities against microbial pathogens is their specific action at microbial membranes that results in selective loss of ions and small nucleotides chiefly ATP. One model cationic peptide that induces non-lytic release of ATP from the fungal pathogen Candida albicans is salivary histatin 5 (Hst 5). The major characteristic of Hst 5-induced ATP release is that it occurs rapidly while cells are still metabolically active and have polarized membranes, thus precluding cell lysis as the means of release of ATP. Other cationic peptides that induce selective release of ATP from target microbes are lactoferricin, human neutrophil defensins, bactenecin, and cathelicidin peptides. The role of released extracellular ATP induced by cationic peptides is not known, but localized increases in extracellular ATP concentration may serve to potentiate cell killing, facilitate further peptide uptake, or function as an additional signal to activate the host innate immune system at the site of infection

Gel immobilization improves survival of Escherichia coli under temperature stress in nutrient-poor natural water

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Bacteriological analysis of water by potentiometric measurement of lipoic acid reduction: preliminary assays for selective detection of indicator organisms.

The practical task of adapting an original potentiometric technique to the bacteriological analysis of water is discussed. Various laboratory strains of organisms belonging to the usual aquatic flora were inoculated one by one in a minimal lactose broth supplied with lipoic (thioctic) acid. The time evolution of the redox potential of the cultures was followed during incubation by combined gold versus reference electrodes. When the incubation temperature was regulated at 36 degrees C, most organisms were able to grow and to reduce the coenzyme, generating changes in the redox potential of the culture. However, very few organisms developed significant reductive activity when the temperature was increased to 41 degrees C and when the broth was provided with sodium deoxycholate. Among the fecal coliform organisms, only Escherichia coli and Klebsiella pneumoniae exhibited early but reproducible potential-time responses. Positive potentiometric responses were also recorded with Acinetobacter calcoaceticus. E. coli showed rapid potentiometric signals as compared with K. pneumoniae. The time required for 100-mV shift of potential to be detected was related to the logarithm of the initial concentration of E. coli or K. pneumoniae in the culture broth. Experiments on natural surface water samples showed the the potentiometric method, associated with the selective incubation conditions, mainly detected E. coli among the bacterial flora of the tested environmental water. The calibration curve relating the time required for a 100-mV shift of potential to be detected to the number of fecal coliforms, as determined by control fecal coliform-selective plate counts, was consistent with the composite standard curve of detection times obtained with six different laboratory strains of E. coli.(ABSTRACT TRUNCATED AT 250 WORDS

Distribution of eukaryotic plankton in the English Channel and the North Sea in summer

The distribution of eukaryotic plankton was investigated in the English Channel and the North Sea during the MICROVIR cruise in summer 2007. The size distribution of autotrophic, heterotrophic eukaryotes and species composition was analyzed with a focus on two major divisions, Haptophyta and Chlorophyta, targeted by 18S rRNA probes. Picoeukaryotes (<2 mu m) dominated over the larger eukaryotes at all stations. Eukaryotes larger than 5 mu m were mainly composed of diatoms in the English Channel and of dinoflagellates in the North Sea. The contribution of Haptophyta was maximal in the 2 to 5 pm fraction and they appeared more abundant in the central region of the North Sea. Chlorophyta, especially Micromonas pusilla, generally dominated the picoplanktonic fraction in the English Channel. Micromonas contribution decreased between the South and the North-east of the North Sea and it was even absent at some stations. Although this species is dominant among the picoeukaryote community of the English Channel, other Chlorophyta species may also play an important ecological role in these temperate ecosystems

Occurrence and Phenotypic Characterization of Yersinia ruckeri Strains with Biofilm-Forming Capacity in a Rainbow Trout Farm

The presence of Yersinia ruckeri in a French fish farm was investigated. Y. ruckeri was isolated mainly from algae and sediment samples rather than from water. Twenty-two Y. ruckeri isolates were obtained, and three strains were distinguished by enterobacterial repetitive intergenic consensus PCR amplification. These strains were able to adhere to solid supports. This characteristic was correlated with flagellum-mediated motility. Killing experiments showed that sessile cells were more resistant to oxolinic acid than their planktonic counterparts. Our results demonstrate that surface colonization of fish farm tanks by Y. ruckeri biofilms is a potential source of recurrent infection for extended periods of time

A new antibacterial and antioxidant S07-2 compound produced by Bacillus subtilis B38

An antibacterial compound, S07-2, was purified to homogeneity by hydrophobic interaction, anion exchange, C18 reverse-phase and HS PEG HPLC. The molecular mass of S07-2 was 905.6 Da as determined by MS. The S07-2 compound was resistant to high temperatures (up to 100 1C) and could withstand a wide range of pH from 3 to 10. In addition, its antibacterial activity was preserved after treatment with proteases. Biochemical characterization revealed its cyclic peptide structure. This compound showed a bactericidal effect against important food- spoilage bacteria and food-borne pathogens including Listeria monocytogenes and Enterococcus faecalis with lethal concentration values of 62.5 mg mL1 and against Salmonella enteritidis at a concentration of 31.25 mg mL1 . However, no cytotoxic effect against human erythrocytes was recorded. Furthermore, the S07-2 com- pound displayed a remarkable Fe 21 -chelating activity (EC50 = 9.76 mg mL1 ) and 1-diphenyl-2-picrylhydrazyl-scavenging capacity (IC50 = 65 mg mL1 ). All these chemical and biological features make S07-2 a useful compound in the food industry as a natural preservative

In vivo and ex vivo longitudinal follow-up of resveratrol supplementation or restauration of a normal diet in female rat hearts submitted to high-fat-high-sucrose diet

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High-grade trichoblastic carcinoma with sarcomatoid differentiation harboring TP53 and PIK3CA mutations

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