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Reactive oxygen species are believed to perform multiple roles during plant defense and possibly as cellular signaling molecules. In animals, nitric oxide (NO) is an important redox-active signaling molecule. Here we show that infection of resistant, but not susceptible, tobacco with tobacco mosaic virus resulted in enhanced NO synthase (NOS) activity. Furthermore, administration of NO donors or recombinant mammalian NOS to tobacco plants or tobacco suspension cells triggered expression of the defense-related genes encoding pathogenesis-related 1 protein and phenylalanine ammonia lyase (PAL). These genes were also induced by cyclic GMP (cGMP) and cyclic ADP-ribose, two molecules that can serve as second messengers for NO signaling in mammals. Consistent with cGMP levels. Furthermore, NO-induced activation of PAL was blocked by 6-anilino-5,8-quinolinedione and 1H-(1,2,4)-oxadizole[4,3-alpha]quinoxalin-1-one, two inhibitors of guanylate cyclase. Although 6-anilino-5,8-quinolinedione fully blocked PAL activation, inhibition by 1H-(1,2,4)-oxadiozole[4,3-alpha]quinoxalin-1-one was not entirely complete, suggesting the existence of cGMP-independent, as well as cGMP-dependent, NO signaling. We conclude that several critical players of animal NO signaling are also operative in plants

Results of transgenetic studies argue that the scrapie isoform of the prion protein (PrPSc) interacts with the substrate cellular PrP (PrPC) during conversion into nascent PrPSc. While PrPSc appears to accumulate primarily in lysosomes, caveolae-like domains (CLDs) have been suggested to be the site where PrPC is converted into PrPSc. We report herein that CLDs isolated from scrapie-infected neuroblastoma (ScN2a) cells contain PrPC and PrPSc. After lysis of ScN2a cells in ice-cold Triton X-100, both PrP isoforms and an N-terminally truncated form of PrPC (PrPC-II) were found concentrated in detergent-insoluble complexes resembling CLDs that were isolated by flotation in sucrose gradients. Similar results were obtained when CLDs were purified from plasma membranes by sonication and gradient centrifugation; with this procedure no detergents are used, which minimizes artifacts that might arise from redistribution of proteins among subcellular fractions. The caveolar markers ganglioside GM1 and H-ras were found concentrated in the CLD fractions. When plasma membrane proteins were labeled with the impermeant reagent sulfo-N-hydroxysuccinimide-biotin, both PrPC and PrPSc were found biotinylated in CLD fractions. Similar results on the colocalization of PrPC and PrPSc were obtained when CLDs were isolated from Syrian hamster brains. Our findings demonstrate that both PrPC and PrPSc are present in CLDs and, thus, support the hypothesis that the PrPSc formation occurs within this subcellular compartment

Cells in a plant differentiate according to their positions and use cell-cell communication to assess these positions. Similarly, single cells in suspension cultures can develop into somatic embryos, and cell-cell communication is thought to control this process. The monoclonal antibody JIM8 labels an epitope on cells in specific positions in plants. JIM8 also labels certain cells in carrot embryogenic suspension cultures. We have used JIM8 and secondary antibodies coupled to paramagnetic beads to label and immunomagnetically sort single cells in a carrot embryogenic suspension culture into pure populations. Cells in the JIM8(+) population develop into somatic embryos, whereas cells in the JIM8(-) population do not form somatic embryos. However, certain cells in JIM8(+) cultures (state B cells) undergo asymmetric divisions, resulting in daughter cells (state C cells) that do not label with JIM8 and that sort to JIM8(-) cultures. State C cells are competent to form somatic embryos, and we show here that a conditioned growth medium from a culture of JIM8(+) cells allows state C cells in a JIM8(-) culture to go on and develop into somatic embryos. JIM8 labels cells in suspension cultures at the cell wall. Therefore, a cell with a role in cell-cell communication and early cell fate selection can be identified by an epitope in its cell wall

We present data showing that some foods preserved in lacquer-coated cans and the liquid in them may acquire estrogenic activity. Hormonal activity was measured using the E-screen bioassay. The biological activity of vegetables packed in cans was a result of plastic monomers used in manufacturing the containers. The plastic monomer bisphenol-A, identified by mass spectrometry, was found as a contaminant not only in the liquid of the preserved vegetables but also in water autoclaved in the cans. The amount of bisphenol-A in the extracts accounted for all the hormonal activity measured. Although the presence of other xenoestrogens cannot be ruled out, it is apparent that all estrogenic activity in these cans was due to bisphenol-A leached from the lacquer coating. The use of plastic in food-packaging materials may require closer scrutiny to determine whether epoxy resins and polycarbonates contribute to human exposure to xenoestrogens.

The purinergic receptor P2Y, G protein coupled, 14 (P2Y14) receptor for UDP-glucose and other UDP-sugars has been implicated in the regulation of the stem cell compartment as well as neuroimmune function. However, the role of P2Y14 in osteoclast formation is completely unknown. We found that RANKL selectively induced P2Y14 among seven mammalian P2Y receptors when analysed at both the mRNA and protein level, but inhibitors of the mitogenactivated protein (MAP) kinase pathway suppressed induction of P2Y14 proteins. Extracellular addition of UDP-sugars such as UDP-glucose, UDP-galactose, UDP-glucuronic acid, and UDP-N-acetyl glucosamine promoted RANKLinduced osteoclastogenesis, while P2Y14 downregulation by RNA interference inhibited osteoclast formation. Taken together, these results suggest that P2Y14 may act as the receptor for UDP-sugars in osteoclast precusors

Recently, Park et al. (2006) succeeded in cultivating the toxic dinoflagellate Dinophysis acuminata and maintaining them by feeding the ciliate Myrionecta rubra grown with a cryptophyte Teleaulax sp. After this report, the present study is the second report of propagation of a Dinophysis species (Dinophysis caudata) under laboratory conditions and describes the maintenance of several clonal strains kept at high abundance (5,000 cells/mL) for a relatively long period (4 months) when fed on M. rubra with the addition of Teleaulax amphioxeia. We confirmed that D. caudata swam actively around its ciliate prey and inserted its peduncle (feeding tube) into the ciliate. Thereafter, the prey became immobile and rounded. Dinophysis caudata actively ingested the cytoplasm of the prey through the peduncle. Dinophysis caudata grew at a growth rate of 1.03 divisions/day when supplied with M. rubra as prey, reaching a maximum concentration of ca. 5,000 cells/well (810 microL) during a 9 day growth experiment. In contrast, a culture of D. caudata was not able to be established in the absence of the ciliate or when provided with T. amphioxeia only, suggesting that D. caudata can not directly utilize T. amphioxeia as prey.

Manipulation of plant natural product biosynthesis through genetic engineering is an attractive but technically challenging goal. Here, we demonstrate that different secondary metabolites can be produced in cultured maize cells by ectopic expression of the appropriate regulatory genes. Cell lines engineered to express the maize transcriptional activators C1 and R accumulate two cyanidin derivatives, which are similar to the predominant anthocyanin found in differentiated plant tissues. In contrast, cell lines that express P accumulate various 3-deoxy flavonoids. Unexpectedly, P-expressing cells in culture also accumulate phenylpropanoids and green fluorescent compounds that are targeted to different subcellular compartments. Two endogenous biosynthetic genes (c2 and a1, encoding chalcone synthase and flavanone/dihydroflavonol reductase, respectively) are independently activated by ectopic expression of either P or C1/R, and there is a dose-response relationship between the transcript level of P and the degree to which c2 or a1 is expressed. Our results support a simple model showing how the gene encoding P may act as a quantitative trait locus controlling insecticidal C-glycosyl flavone level in maize silks, and they suggest how p1 might confer a selective advantage against insect predation in maize

Description of the subject. Variability observed in sensory characteristics of “attiéké” results from an uncontrolled fermentation process due to the use of artisanal starters. Objectives. This study aims to screen microbial strains for their use during fermentation of cassava dough into attieké. Method. Technological properties of three lactic acid bacteria (LAB) isolated from artisanal starters were highlighted in vitro, and these LAB were identified as either Weissella cibaria or Weissella confusa by Matrix Assisted Laser Desorption Ionisation-Mass Spectrometry (MALDI-TOF MS).Results. The three Weissella isolates Wc 69, Wc 21 and Wc 114 induced in less than 42 h a decrease below 4.2 (main food safety factor) of the initial pH of MRS (de Man, Rogosa and Sharpe) broth. These strains are osmotolerant, present alpha-amylase activity and ferment the indigestible sugar raffinose. Moreover isolates Wc 114 and Wc 69 are thermotolerant, while Wc 114 presents a pectinase activity necessary for cassava dough softening.Conclusions. Considering their technological properties, the three isolated Weissella strains could be suitable in optimizing and standardizing the quality of attieké. Isolement et sélection de souches de Weissella comme de potentiels ferments pour la production d’attiékéDescription du sujet. La fermentation non contrôlée de l’attieké, effectuée à partir d’inocula traditionnels, est responsable de la grande variabilité sensorielle observée pour cette denrée alimentaire.Objectifs. La présente étude vise à sélectionner des micro-organismes aptes à être utilisés comme des ferments microbiens pour une fermentation contrôlée de la pâte de manioc en attieké.Méthode. Trois bactéries lactiques isolées de ferments traditionnels sont identifiées comme étant Weissella cibaria ou Weissella confusa par la technique de désorption-ionisation laser assistée par matrice couplée au spectromètre de masse à temps de vol (MALDI-TOF MS) et leurs propriétés technologiques mises en évidence in vitro.Résultats. Les trois isolats de Weissella induisent une baisse du pH initial (principal facteur de sécurité alimentaire) de 6,2 du bouillon MRS (de Man, Rogosa and Sharpe) à une valeur en dessous de 4,2 en moins de 42 h. En plus de présenter une activité alpha-amylase, ces bactéries fermentent le raffinose, un sucre indigeste. Toutes les trois sont osmotolérantes. Par ailleurs, les isolats Wc 114 et Wc 69 sont thermotolérants, tandis que l’isolat Wc 114 présente une activité pectinase nécessaire au ramollissement de la pâte de manioc. Conclusions. Les trois bactéries lactiques isolées (Wc 69, Wc 21 and Wc 114) présentent des propriétés technologiques intéressantes susceptibles de convenir pour contrôler et standardiser la qualité de l’attieké.

A simple method was established to prepare DNA from fungal mycelia cultured on an agar plate. The fungi tested successfully with this method contained Zygomycetes, Ascomycetes, Basidiomycetes, and Oomycetes. This method did not require any time-consuming steps to crush or digest mycelia or fractionation in a phenol-chloroform mixture. The DNA was easily extracted by immersing and dispersing the mycelial plugs in a specific buffer (200mM Tris-HCl, 50mM ethylenediaminetetraacetic acid, 200mM NaCl, 1% n-lauroylsarcosine, pH 8.0), then concentrated by ethanol precipitation. The total time to complete the whole procedure was less than 1h. The quality and quantity were sufficient for polymerase chain reaction amplification and Southern blot analysis. [PUBLICATION ABSTRACT]

The yellow-green alga Trachydiscus minutus (class Xanthophyta) was cultivated in a standard medium and in media without sulfur and nitrogen. Its yield after a 16-d cultivation reached 13 g dry mass per 1 L medium. The content of oligoenoic fatty acid, i.e. eicosapentaenoic, was in excess of 35 % of total fatty acids; the productivity was thus 88 mg/L per d. This result makes the alga a very prospective organism that may serve as a new biotechnological source of single cell oil.