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Growth and Survival of Streptomycete Inoculants and Extent of Plasmid Transfer in Sterile and Nonsterile Soil

Wellington, Elizabeth M. H.; Cresswell, Neil; Saunders, Venetia A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1990 EN
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The growth and survival of strains of Streptomyces lividans and S. violaceolatus in sterile and nonsterile soil was investigated by using inoculated soil microcosms run as batch systems. It was evident that, after an initial short mycelial growth phase of 2 to 3 days, sporulation occurred and inoculants survived as spores. The transfer of a high-copy-number, self-transmissible plasmid, pIJ673, was detected by using intra- and interspecific crosses. The initial detection of transconjugants correlated with the development of the mycelial state of the inoculants (as confirmed by scanning electron microscopy) after 2 days of incubation. Subsequent spread of the plasmid was attributed to spread within existing mycelium followed by sporulation. In natural soil, inoculant numbers remained constant or declined, but plasmid transfer was readily detected.

Dialysis Membrane Technique for Studying Microbial Interaction

Nordbring-Hertz, B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1983 EN
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A dialysis membrane method is described which allows (i) cultivation of fungi on an agar support, (ii) observation of growth and development by direct light microscopy, (iii) transfer of cultures from agar surfaces for subsequent treatments or for biochemical analysis, and (iv) preparation for scanning electron microscopy. The method is used routinely in studies of fungus-nematode and fungus-fungus interactions.

Discrete Functions of TRAF1 and TRAF2 in Drosophila melanogaster Mediated by c-Jun N-Terminal Kinase and NF-κB-Dependent Signaling Pathways

Cha, Guang-Ho; Cho, Kyoung Sang; Lee, Jun Hee; Kim, Myungjin; Kim, Euysoo; Park, Jeehye; Lee, Sung Bae; Chung, Jongkyeong
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2003 EN
Relevância na Pesquisa
565.76758%
Two Drosophila tumor necrosis factor receptor-associated factors (TRAF), DTRAF1 and DTRAF2, are proposed to have similar functions with their mammalian counterparts as a signal mediator of cell surface receptors. However, their in vivo functions and related signaling pathways are not fully understood yet. Here, we show that DTRAF1 is an in vivo regulator of c-Jun N-terminal kinase (JNK) pathway in Drosophila melanogaster. Ectopic expression of DTRAF1 in the developing eye induced apoptosis, thereby causing a rough-eye phenotype. Further genetic interaction analyses revealed that the apoptosis in the eye imaginal disc and the abnormal eye morphogenesis induced by DTRAF1 are dependent on JNK and its upstream kinases, Hep and DTAK1. In support of these results, DTRAF1-null mutant showed a remarkable reduction in JNK activity with an impaired development of imaginal discs and a defective formation of photosensory neuron arrays. In contrast, DTRAF2 was demonstrated as an upstream activator of nuclear factor-κB (NF-κB). Ectopic expression of DTRAF2 induced nuclear translocation of two Drosophila NF-κBs, DIF and Relish, consequently activating the transcription of the antimicrobial peptide genes diptericin, diptericin-like protein, and drosomycin. Consistently...

Microbial Synergy via an Ethanol-Triggered Pathway

Smith, Michael G.; Des Etages, Shelley G.; Snyder, Michael
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2004 EN
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578.70477%
We have discovered a microbial interaction between yeast, bacteria, and nematodes. Upon coculturing, Saccharomyces cerevisiae stimulated the growth of several species of Acinetobacter, including, A. baumannii, A. haemolyticus, A. johnsonii, and A. radioresistens, as well as several natural isolates of Acinetobacter. This enhanced growth was due to a diffusible factor that was shown to be ethanol by chemical assays and evaluation of strains lacking ADH1, ADH3, and ADH5, as all three genes are involved in ethanol production by yeast. This effect is specific to ethanol: methanol, butanol, and dimethyl sulfoxide were unable to stimulate growth to any appreciable level. Low doses of ethanol not only stimulated growth to a higher cell density but also served as a signaling molecule: in the presence of ethanol, Acinetobacter species were able to withstand the toxic effects of salt, indicating that ethanol alters cell physiology. Furthermore, ethanol-fed A. baumannii displayed increased pathogenicity when confronted with a predator, Caenorhabditis elegans. Our results are consistent with the concept that ethanol can serve as a signaling molecule which can affect bacterial physiology and survival.

The IκB Kinase Complex and NF-κB Act as Master Regulators of Lipopolysaccharide-Induced Gene Expression and Control Subordinate Activation of AP-1

Krappmann, Daniel; Wegener, Elmar; Sunami, Yoshiaki; Esen, Meral; Thiel, Andreas; Mordmuller, Benjamin; Scheidereit, Claus
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /07/2004 EN
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557.86113%
Toll-like receptors (TLRs) recognize conserved products of microbial pathogens to initiate the innate immune response. TLR4 signaling is triggered upon binding of lipopolysaccharides (LPS) from gram-negative bacteria. Using comparative gene expression profiling, we demonstrate a master regulatory role of IκB kinase (IKK)/NF-κB signaling for immediate-early gene induction after LPS engagement in precursor B cells. IKK/NF-κB signaling controls a large panel of gene products associated with signaling and transcriptional activation and repression. Intriguingly, the induction of AP-1 activity by LPS in precursor B cells and primary dendritic cells fully depends on the IKK/NF-κB pathway, which promotes expression of several AP-1 family members, including JunB, JunD, and B-ATF. In pre-B cells, AP-1 augments induction of a subset of primary NF-κB targets, as shown for chemokine receptor 7 (CCR7) and immunoglobulin κ light chain. Thus, our data illustrate that NF-κB orchestrates immediate-early effects of LPS signaling and controls secondary AP-1 activation to mount an appropriate biological response.

A Cellulose Synthase-Like Protein Involved in Hyphal Tip Growth and Morphological Differentiation in Streptomyces▿

Xu, Hongbin; Chater, Keith F.; Deng, Zixin; Tao, Meifeng
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
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571.60742%
Cellulose synthase and cellulose synthase-like proteins, responsible for synthesizing β-glucan-containing polysaccharides, play a fundamental role in cellular architectures, such as plant cell and tissue morphogenesis, bacterial biofilm formation, and fruiting-body development. However, the roles of the proteins involved in the developmental process are not well understood. Here, we report that a cellulose synthase-like protein (CslASc) in Streptomyces has a function in hyphal tip growth and morphological differentiation. The cslASc replacement mutant showed pleiotropic defects, including the severe delay of aerial-hyphal formation and altered cell wall morphology. Calcofluor white fluorescence analysis demonstrated that polysaccharide synthesis at hyphal tips was dependent on CslASc. cslASc was constitutively transcribed, and an enhanced green fluorescent protein-CslASc fusion protein was mostly located at the hyphal tips. An extract enriched in morphogenetic chaplin proteins promoted formation of aerial hyphae by the mutant. Furthermore, a two-hybrid experiment indicated that the glycosyltransferase domain of CslASc interacted with the tropomyosin-like polarity-determining DivIVA protein, suggesting that the tip-located DivIVA governed tip recruitment of the CslASc membrane protein. These results imply that the cellulose synthase-like protein couples extracellular and cytoskeletal components functioning in tip growth and cell development.

Hydrogen Peroxide Linked to Lysine Oxidase Activity Facilitates Biofilm Differentiation and Dispersal in Several Gram-Negative Bacteria▿

Mai-Prochnow, Anne; Lucas-Elio, Patricia; Egan, Suhelen; Thomas, Torsten; Webb, Jeremy S.; Sanchez-Amat, Antonio; Kjelleberg, Staffan
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
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558.00246%
The marine bacterium Pseudoalteromonas tunicata produces an antibacterial and autolytic protein, AlpP, which causes death of a subpopulation of cells during biofilm formation and mediates differentiation, dispersal, and phenotypic variation among dispersal cells. The AlpP homologue (LodA) in the marine bacterium Marinomonas mediterranea was recently identified as a lysine oxidase which mediates cell death through the production of hydrogen peroxide. Here we show that AlpP in P. tunicata also acts as a lysine oxidase and that the hydrogen peroxide generated is responsible for cell death within microcolonies during biofilm development in both M. mediterranea and P. tunicata. LodA-mediated biofilm cell death is shown to be linked to the generation of phenotypic variation in growth and biofilm formation among M. mediterranea biofilm dispersal cells. Moreover, AlpP homologues also occur in several other gram-negative bacteria from diverse environments. Our results show that subpopulations of cells in microcolonies also die during biofilm formation in two of these organisms, Chromobacterium violaceum and Caulobacter crescentus. In all organisms, hydrogen peroxide was implicated in biofilm cell death, because it could be detected at the same time as the killing occurred...

Manipulating Each MreB of Bdellovibrio bacteriovorus Gives Diverse Morphological and Predatory Phenotypes▿

Fenton, Andrew Karl; Lambert, Carey; Wagstaff, Peter Charles; Sockett, Renee Elizabeth
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
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566.50234%
We studied the two mreB genes, encoding actinlike cytoskeletal elements, in the predatory bacterium Bdellovibrio bacteriovorus. This bacterium enters and replicates within other Gram-negative bacteria by attack-phase Bdellovibrio squeezing through prey outer membrane, residing and growing filamentously in the prey periplasm forming an infective “bdelloplast,” and septating after 4 h, once the prey contents are consumed. This lifestyle brings challenges to the Bdellovibrio cytoskeleton. Both mreB genes were essential for viable predatory growth, but C-terminal green fluorescent protein tagging each separately with monomeric teal-fluorescent protein (mTFP) gave two strains with phenotypic changes at different stages in predatory growth and development. MreB1-mTFP cells arrested growth early in bdelloplast formation, despite successful degradation of prey nucleoid. A large population of stalled bdelloplasts formed in predatory cultures and predation proceeded very slowly. A small proportion of bdelloplasts lysed after several days, liberating MreB1-mTFP attack-phase cells of wild-type morphology; this process was aided by subinhibitory concentrations of an MreB-specific inhibitor, A22. MreB2-mTFP, in contrast, was predatory at an almost wild-type rate but yielded attack-phase cells with diverse morphologies...

Expression and Physiological Role of Three Myxococcus xanthus Copper-Dependent P1B-Type ATPases during Bacterial Growth and Development ▿ †

Moraleda-Muñoz, Aurelio; Pérez, Juana; Extremera, Antonio Luis; Muñoz-Dorado, José
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
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557.86113%
Myxococcus xanthus is a soil-dwelling bacterium that exhibits a complex life cycle comprising social behavior, morphogenesis, and differentiation. In order to successfully complete this life cycle, cells have to cope with changes in their environment, among which the presence of copper is remarkable. Copper is an essential transition metal for life, but an excess of copper provokes cellular damage by oxidative stress. This dual effect forces the cells to maintain a tight homeostasis. M. xanthus encodes a large number of genes with similarities to others reported previously to be involved in copper homeostasis, most of which are redundant. We have identified three genes that encode copper-translocating P1B-ATPases (designated copA, copB, and copC) that exhibit the sequence motifs and modular organizations of those that extrude Cu+. The expression of the ATPase copC has not been detected, but copA and copB are differentially regulated by the addition of external copper. However, while copB expression peaks at 2 h, copA is expressed at higher levels, and the maximum is reached much later. The fact that these expression profiles are nearly identical to those exhibited by the multicopper oxidases cuoA and cuoB suggests that the pairs CuoB-CopB and CuoA-CopA sequentially function to detoxify the cell. The deletion of any ATPase alters the expression profiles of other genes involved in copper homeostasis...

Microbial Odor Profile of Polyester and Cotton Clothes after a Fitness Session

Callewaert, Chris; De Maeseneire, Evelyn; Kerckhof, Frederiek-Maarten; Verliefde, Arne; Van de Wiele, Tom; Boon, Nico
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2014 EN
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582.5275%
Clothing textiles protect our human body against external factors. These textiles are not sterile and can harbor high bacterial counts as sweat and bacteria are transmitted from the skin. We investigated the microbial growth and odor development in cotton and synthetic clothing fabrics. T-shirts were collected from 26 healthy individuals after an intensive bicycle spinning session and incubated for 28 h before analysis. A trained odor panel determined significant differences between polyester versus cotton fabrics for the hedonic value, the intensity, and five qualitative odor characteristics. The polyester T-shirts smelled significantly less pleasant and more intense, compared to the cotton T-shirts. A dissimilar bacterial growth was found in cotton versus synthetic clothing textiles. Micrococci were isolated in almost all synthetic shirts and were detected almost solely on synthetic shirts by means of denaturing gradient gel electrophoresis fingerprinting. A selective enrichment of micrococci in an in vitro growth experiment confirmed the presence of these species on polyester. Staphylococci were abundant on both cotton and synthetic fabrics. Corynebacteria were not enriched on any textile type. This research found that the composition of clothing fibers promotes differential growth of textile microbes and...

Anti-microbial Use in Animals: How to Assess the Trade-offs

Rushton, J
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
EN
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580.1497%
Antimicrobials are widely used in preventive and curative medicine in animals. Benefits from curative use are clear – it allows sick animals to be healthy with a gain in human welfare. The case for preventive use of antimicrobials is less clear cut with debates on the value of antimicrobials as growth promoters in the intensive livestock industries. The possible benefits from the use of antimicrobials need to be balanced against their cost and the increased risk of emergence of resistance due to their use in animals. The study examines the importance of animals in society and how the role and management of animals is changing including the use of antimicrobials. It proposes an economic framework to assess the trade-offs of anti-microbial use and examines the current level of data collection and analysis of these trade-offs. An exploratory review identifies a number of weaknesses. Rarely are we consistent in the frameworks applied to the economic assessment anti-microbial use in animals, which may well be due to gaps in data or the prejudices of the analysts. There is a need for more careful data collection that would allow information on (i) which species and production systems antimicrobials are used in, (ii) what active substance of antimicrobials and the application method and (iii) what dosage rates. The species need to include companion animals as well as the farmed animals as it is still not known how important direct versus indirect spread of resistance to humans is. In addition...

Studies of Dynamic Protein-Protein Interactions in Bacteria Using Renilla Luciferase Complementation Are Undermined by Nonspecific Enzyme Inhibition

Hatzios, Stavroula-Artemis K.; Ringgaard, Simon; Davis, Brigid; Waldor, Matthew K.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN_US
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557.70945%
The luciferase protein fragment complementation assay is a powerful tool for studying protein-protein interactions. Two inactive fragments of luciferase are genetically fused to interacting proteins, and when these two proteins interact, the luciferase fragments can reversibly associate and reconstitute enzyme activity. Though this technology has been used extensively in live eukaryotic cells, split luciferase complementation has not yet been applied to studies of dynamic protein-protein interactions in live bacteria. As proof of concept and to develop a new tool for studies of bacterial chemotaxis, fragments of Renilla luciferase (Rluc) were fused to the chemotaxis-associated response regulator CheY3 and its phosphatase CheZ in the enteric pathogen Vibrio cholerae. Luciferase activity was dependent on the presence of both CheY3 and CheZ fusion proteins, demonstrating the specificity of the assay. Furthermore, enzyme activity was markedly reduced in V. cholerae chemotaxis mutants, suggesting that this approach can measure defects in chemotactic signaling. However, attempts to measure changes in dynamic CheY3-CheZ interactions in response to various chemoeffectors were undermined by nonspecific inhibition of the full-length luciferase. These observations reveal an unexpected limitation of split Rluc complementation that may have implications for existing data and highlight the need for great caution when evaluating small molecule effects on dynamic protein-protein interactions using the split luciferase technology.

Catecholate Siderophores Protect Bacteria from Pyochelin Toxicity

Adler, Conrado; Corbalán, Natalia S.; Seyedsayamdost, Mohammad; Pomares, María Fernanda; de Cristóbal, Ricardo E.; Clardy, Jon C.; Kolter, Roberto Guillermo; Vincent, Paula A.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN_US
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582.16094%
Background: Bacteria produce small molecule iron chelators, known as siderophores, to facilitate the acquisition of iron from the environment. The synthesis of more than one siderophore and the production of multiple siderophore uptake systems by a single bacterial species are common place. The selective advantages conferred by the multiplicity of siderophore synthesis remains poorly understood. However, there is growing evidence suggesting that siderophores may have other physiological roles besides their involvement in iron acquisition. Methods and Principal Findings: Here we provide the first report that pyochelin displays antibiotic activity against some bacterial strains. Observation of differential sensitivity to pyochelin against a panel of bacteria provided the first indications that catecholate siderophores, produced by some bacteria, may have roles other than iron acquisition. A pattern emerged where only those strains able to make catecholate-type siderophores were resistant to pyochelin. We were able to associate pyochelin resistance to catecholate production by showing that pyochelin-resistant Escherichia coli became sensitive when biosynthesis of its catecholate siderophore enterobactin was impaired. As expected, supplementation with enterobactin conferred pyochelin resistance to the entE mutant. We observed that pyochelin-induced growth inhibition was independent of iron availability and was prevented by addition of the reducing agent ascorbic acid or by anaerobic incubation. Addition of pyochelin to E. coli increased the levels of reactive oxygen species (ROS) while addition of ascorbic acid or enterobactin reduced them. In contrast...

The Evolution of Cell-to-Cell Communication in a Sporulating Bacterium

van Gestel, Jordi; Nowak, Martin A.; Tarnita, Corina
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN_US
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571.8358%
Traditionally microorganisms were considered to be autonomous organisms that could be studied in isolation. However, over the last decades cell-to-cell communication has been found to be ubiquitous. By secreting molecular signals in the extracellular environment microorganisms can indirectly assess the cell density and respond in accordance. In one of the best-studied microorganisms, Bacillus subtilis, the differentiation processes into a number of distinct cell types have been shown to depend on cell-to-cell communication. One of these cell types is the spore. Spores are metabolically inactive cells that are highly resistant against environmental stress. The onset of sporulation is dependent on cell-to-cell communication, as well as on a number of other environmental cues. By using individual-based simulations we examine when cell-to-cell communication that is involved in the onset of sporulation can evolve. We show that it evolves when three basic premises are satisfied. First, the population of cells has to affect the nutrient conditions. Second, there should be a time-lag between the moment that a cell decides to sporulate and the moment that it turns into a mature spore. Third, there has to be environmental variation. Cell-to-cell communication is a strategy to cope with environmental variation...

Stationary Phase-Specific Virulence Factor Overproduction by a lasR Mutant of Pseudomonas aeruginosa

Cabeen, Matthew T.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN_US
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576.70125%
Secreted virulence factors of the human pathogen Pseudomonas aeruginosa are often under quorum sensing control. Cells lacking the quorum-sensing regulator LasR show reduced virulence factor production under typical laboratory conditions and are hypo-virulent in short-term animal infection models, yet lasR mutants are frequently associated with long-term infection in cystic fibrosis patients. Here, I show that in stationary-phase or slow-growth conditions, lasR cells continuously and strongly produce the important virulence factor pyocyanin while wild-type cells do not. Pyocyanin overproduction by lasR cells is permitted by loss of repression by RsaL, a LasR-dependent negative regulator. lasR cells also contribute pyocyanin in mixed cultures, even under “cheating” conditions where they depend on their wild-type neighbors for nutrients. Finally, some clinical P. aeruginosa isolates with lasR mutations can overproduce pyocyanin in the laboratory. These results imply that slow-growing clinical populations of lasR cells in chronic infections may contribute to virulence by producing pyocyanin under conditions where lasR+ cells do not.

Isolamento e caracterização de microrganismos em leite cru refrigerado e leite UHT no estado de Goiás e desenvolvimento de filme ativo antimicrobiano para inibição de Bacillus sporothermodurans; Isolation and characterization of microorganisms in refrigerated raw milk and UHT milk in the state of Goias and development of antimicrobial active film for inhibition of Bacillus sporothermodurans

PEREIRA, Flavio Evans Vilela
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Ciência e Tecnologia de Alimentos; Ciencias Agrárias - Agronomia Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Ciência e Tecnologia de Alimentos; Ciencias Agrárias - Agronomia
Tipo: Dissertação Formato: application/pdf
POR
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580.80367%
Raw milk is a natural culture medium for the microbial growth and easy deterioration, because of that, thermal processing is needed as soon as possible. A new technology has been used to improve the food quality, active packaging, such as antimicrobial films, wich the intention to control the microbial growth in the products. The aim of this study was to evaluate the UHT milk quality produced in Goiás State, isolation and identification of Bacillus sporothermodurans, beside create a antimicrobial film for inhibition of this microrganism high heat resistance spore former. The isolation of psychrotrophic in raw milk was used PCA with incubation at 21 °C for 72h. To evaluate the UHT milk has been doing research on aerobic mesophilic in PCA with incubation at 30 °C for 72h and to thermoresistents microrganisms was in ABHI with incubation at 35 °C for 48h. The identification of isolates was performed according to convetional methods of biochemistry identification. From raw milk, the psychrotrophic microrganisms most isolates were Staphylococcus sp. and Corynebacterium sp., both with 21,5% from 70 isolates, verifying a higher contauge of Gram-positive microrganisms (82,85%). Considering the 157 UHT isolates, just 31 were identified as Gram-positive microrganisms through biochemical tests...

Legume rotation effects on early growth and rhizosphere microbiology of sorghum in West African soils

Marschner, P.; Joergensen, R.; Piepho, H.; Buerkert, A.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
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583.54766%
Cereal yield increases in legume rotations on west African soils were the subject of much recent research aiming at the development of more productive cropping systems for the mainly subsistence-oriented agriculture in this region. However, little has been done to elucidate the possible contribution of soil microbiological factors to these rotation effects. Therefore a pot trial was conducted using legume rotation and continuous cereal soils each from one site in Burkina Faso and two sites in Togo where cropping system experiments had been conducted over 4 yrs. All soils were planted with seedlings of sorghum (Sorghum bicolor L. Moench). From 21 days after sowing onwards relative growth rates in rotation soils were higher than in the continuous cereal soils, resulting in between 69 and 500% higher shoot dry matter of rotation sorghum compared to sorghum growing in continuous cereal soils. Across sites rotation soils were characterized by higher pH, higher microbial N and a lower microbial biomass C/N ratio and, with the exception of one site, a higher fungal biomass in the rhizosphere. The bacterial and eukaryal community structure in the soil, assessed by denaturing gradient gel electrophoresis (DGGE), differed between sites. However...

Technology and raw material quality to underpin the Irish fresh-cut fruit industry

Finnegan, Elizabeth M
Fonte: University of Limerick Publicador: University of Limerick
Tipo: info:eu-repo/semantics/doctoralThesis; all_ul_research; ul_published_reviewed; ul_theses_dissertations
ENG
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558.27297%
peer-reviewed; The objective of this thesis was to contribute to improving the quality of fresh-cut fruits by identifying how raw material use, processing, packaging and storage might be optimised. Effects of intrinsic and extrinsic factor variables on the quality, microbiology and phytochemical content were determined. Following comprehensive quality evaluations, principal component analysis (PCA) was employed, and the biplots generated were effective in characterising patterns of deterioration and in tracking differences in quality in terms of the rate and extent of change. Ripeness stage/ physiological age, geographical origin, cut size and packaging type had large effects on quality (p<0.05) as did storage temperature and time (p<0.01). There were significant effects of controlled and modified atmospheres on quality (p<0.05), but little effect on microbial growth or phytochemical (total phenolic, total carotenoid, total antioxidant activity) content (p>0.05). In general, product modified atmosphere (PMA) packs displayed a steadier rate of quality loss with more consistent end-product quality. A CA of 5%O2+5%CO2 was best at maintaining fresh-cut pineapple and cantaloupe melon quality, while a CA of 97%N2+3%O2 was best for fresh-cut kiwifruit. Exposure to sub-optimal atmospheres resulted in physiological disorders such as discolouration...

Evidence-Based Annotation of the Malaria Parasite's Genome Using Comparative Expression Profiling

Zhou, Yingyao; Ramachandran, Vandana; Kumar, Kota Arun; Westenberger, Scott; Refour, Phillippe; Zhou, Bin; Li, Fengwu; Young, Jason A.; Chen, Kaisheng; Plouffe, David; Henson, Kerstin; Nussenzweig, Victor; Carlton, Jane; Vinetz, Joseph M.; Winzeler, Eliza
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
567.31047%
A fundamental problem in systems biology and whole genome sequence analysis is how to infer functions for the many uncharacterized proteins that are identified, whether they are conserved across organisms of different phyla or are phylum-specific. This problem is especially acute in pathogens, such as malaria parasites, where genetic and biochemical investigations are likely to be more difficult. Here we perform comparative expression analysis on Plasmodium parasite life cycle data derived from P. falciparum blood, sporozoite, zygote and ookinete stages, and P. yoelii mosquito oocyst and salivary gland sporozoites, blood and liver stages and show that type II fatty acid biosynthesis genes are upregulated in liver and insect stages relative to asexual blood stages. We also show that some universally uncharacterized genes with orthologs in Plasmodium species, Saccharomyces cerevisiae and humans show coordinated transcription patterns in large collections of human and yeast expression data and that the function of the uncharacterized genes can sometimes be predicted based on the expression patterns across these diverse organisms. We also use a comprehensive and unbiased literature mining method to predict which uncharacterized parasite-specific genes are likely to have roles in processes such as gliding motility...

The long-term effects of the management of a forest soil on its carbon content, microbial biomass and activity under a semi-arid climate

Bastida, F.; Moreno, J. L.; Hernández Fernández Muñoz, María Teresa; García Izquierdo, Carlos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 190855 bytes; application/pdf
ENG
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581.1723%
10 pages, 2 figures, 5 tables.; Terracing of soil is a reforestation practice well established in South-eastern Spain (semi-arid climate), because it increases plant growth by means of run-off reduction. This is a crucial factor because in this zone the climatic conditions (especially the scarce rainfall) impede plant development. In this work, the influence in the long-term (13 years) of two types of physical management (terracing and strip planting) in the reforestation of a mountainside with Pinus halepensis Millar, together with the addition of an organic amendment (produced from municipal refuse), was evaluated by means of different biochemical and microbiological parameters, including those related to the size and general activity of microbial populations, such as microbial biomass C (MBC), basal respiration, ATP, dehydrogenase activity and hydrolase activities. Also, the study of labile C fractions (water-soluble C, WSC) provided information regarding the metabolic potential of the soil microorganisms. Three-way ANOVA showed that organic amendment significantly increased general microbial activity and carbon fractions. Strips produced, in the long-term, only a slightly positive effect on the microbial activity. The results indicate that terracing...