Biosynthesis of Depsipeptide Mycotoxins in Fusarium     

Till Hornbogen  Mirko Glinski  Rainer Zocher 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(7):713-718

The cyclic hexadepsipeptide enniatin is known as a phytopathogenic compound from Fusaria causing necrosis and wilt. The molecule consists of three alternating residues each of a branched chain amino acid and D-hydroxyisovaleric acid (D-Hiv). Enniatins are synthesized by a 347kDa multienzyme (enniatin synthetase) via a thiol template mechanism. The corresponding gene esyn1 has an open reading frame of 9393 nucleotides and harbours two modules, one responsible for D-hydroxy acid activation and one for L-amino acid activation with an integrated N-methyltransferase domain. Such methyltransferases build an homologous group among N-methyl peptide synthetases. Enniatins are synthesized by step-wise condensation of dipeptidol building blocks in an iterative manner resembling fatty acid synthesis. A key enzyme in enniatin biosynthesis is the NADPH-dependent D-2-hydroxyisovalerate dehydrogenase, that supplies enniatin synthetase with D-Hiv. Enniatins contribute to the wilt toxic character of Fusaria. Virulence was significantly reduced in F. avenaceum after disruption of the esyn1 gene.  相似文献   

Phenotypic plasticity of two invasive alien plant species inside a deciduous forest in a strict nature reserve in Italy     

Mirko Umberto Granata  Francesco Bracco 《Journal of Sustainable Forestry》2020,39(4):346-364

ABSTRACT

Invasive alien plant species (IAPs) represent one of the main biological threats to biodiversity worldwide. Information about their phenotypic plasticity are needed to increase awareness about their future invasive potential. A study about phenotypic plasticity in response to contrasting light regimes and its quantification by a plasticity index (PI) of two IAPs (Ailanthus altissima and Robinia pseudoacacia) inside a Strict Nature Reserve was conducted. R. pseudoacacia showed a 70% higher PI, with a strongly greater value at morphological leaf level, associated with a greater ability to survive and grow in forest understory, explaining its greater widespread. Otherwise, A. altissima showed its highest PI at physiological level, which was associated with the ability to colonize and grow in environments with high-light regimes. Based on these results, the conservative management has limited the presence of A. altissima by its lower ability to grow in forest understory. In fact, the small-scale gaps in the forest infrastructure, that could allow its recruitment, are originated only from the death of a single tree or small group of trees. Regarding R. pseudoacacia, it is critical to maintain this type of management because any disturbances resulting in large openings could further promote its presence inside the Reserve.  相似文献   

Characterization of Dietary Fiber Polysaccharides from Dehulled Common Buckwheat (Fagopyrum esculentum) Seeds     

Daniel Wefers  Mirko Bunzel 《Cereal Chemistry》2015,92(6):598-603

Buckwheat is a pseudocereal that has gained increasing interest of industry and consumers over the past decade. Little, however, is known about its dietary fiber composition and nonstarch polysaccharide structures. Analysis of the monosaccharide composition indicated large amounts of pectic polysaccharides in both insoluble and soluble fiber from buckwheat. Methylation analysis gave further insights into the structures of the polysaccharides. The corresponding partially methylated alditol acetates suggested only low amounts of galactans. Xyloglucans were the main hemicellulosic polysaccharides in the insoluble fiber fraction. Highly branched arabinans, exclusively substituted at position O3, were of higher abundance. These results were confirmed by screening endo‐arabinanase and endo‐galactanase liberated oligosaccharides with high‐performance anion‐exchange chromatography with pulsed amperometric detection and LC‐MS². Application of this method also demonstrated highly branched arabinan areas within the pectic polysaccharides. Only low amounts of fiber associated hydroxycinnamic acids and diferulic acids were liberated by alkaline treatment, and no evidence was found for their attachment to polysaccharides, suggesting only a minor impact of these structural elements on fiber structures in dehulled buckwheat seeds.  相似文献   

Abstracts of papers presented at the 9th meeting of the international council for the study of viruses and virus diseases of the grapevine     

William B. Hewitt  Marc Fuchs  Bernard Walter  Monique Pinck  Lothaire Pinck  G. Belli  P. A. Bianco  A. Fortusini  Giovanni Granata  Anna Appiano  et al. 《Phytoparasitica》1989,17(1):57-78

  相似文献   

Effect of fast protein liquid chromatography fractionated salivary gland extracts from different ixodid tick species on interleukin-8 binding to its cell receptors   总被引：2，自引：0，他引：2  

Kocáková P  Sláviková M  Hajnická V  Slovák M  Gasperík J  Vancová I  Fuchsberger N  Nuttall PA 《Folia parasitologica》2003,50(1):79-84

Interleukin-8 plays a critical role in inflammatory processes. Hence generation of molecules with anti-IL-8 activity is likely to be important for successful feeding and for survival of the ticks. Anti-IL-8 activity was studied in saliva of three ixodid tick species--Dermacentor reticulatus (Fabricius, 1794), Rhipicephalus appendiculatus Neumann, 1901, and Amblyomma variegatum (Fabricius, 1794). The greatest activity was shown in saliva prepared from D. reticulatus. The activity was attributed to tick salivary gland molecules that bind to IL-8, preventing binding of the chemokine to its specific receptor, rather than to occupation of the IL-8 cell receptor by the tick molecules. The distribution of anti-IL-8 activity in fast protein liquid chromatography (FPLC) fractions of salivary gland extracts (SGE) derived from adult female D. reticulatus, R. appendiculatus and A. variegatum was compared directly by both ELISA and receptor-binding inhibition assays. The correspondence in results with fractions of SGE from ELISA is consistent with detection of tick molecules that inhibit IL-8 binding to its receptor. As IL-8 is an important chemoattractant and activator of neutrophils, the presence of an anti-IL-8 activity in tick saliva indicates that neutrophils play an important role in the host response to parasitism by ticks.  相似文献   

Effects of nonesterified fatty acids and beta-hydroxybutyrate on functions of mononuclear cells obtained from ewes     

Lacetera N  Franci O  Scalia D  Bernabucci U  Ronchi B  Nardone A 《American journal of veterinary research》2002,63(3):414-418

OBJECTIVE: To assess the effects of nonesterified fatty acids (NEFA) and beta-hydroxybutyrate (BHBA) on functions of mononuclear cells obtained from ewes. ANIMALS: 6 Sardinian ewes. PROCEDURE: Mononuclear cells were cultured with concentrations of NEFA (0, 15.6, 31.2, 62.5, 125, 250, 500, 1,000, or 2,000 micromol/L) and BHBA (0, 0.45, 0.9, 1.8, or 3.6 mmol/L). Concentrations of NEFA and BHBA were intended to mimic those of ketotic or healthy ewes, and NEFA and BHBA were tested alone and in combination. Synthesis of DNA was stimulated by use of concanavalin A (Con A) or pokeweed-mitogen (PWM). Secretion of IgM was stimulated by use of PWM. RESULTS: Synthesis of DNA stimulated by Con A and PWM was significantly inhibited by high concentrations of NEFA (> or = 250 micromol/L) or by a combination of high concentrations of NEFA (> or = 250 micromol/L) and all concentrations of BHBA (> or = 0.45 mmol/L). In contrast, DNA synthesis was not inhibited by low concentrations of NEFA (< or = 125 micromol/L) or by a combination of low concentrations of NEFA (< or = 125 micromol/L) and the lowest concentration of BHBA (0.45 mmol/L). Secretion of IgM was significantly inhibited by all concentrations of NEFA and by all combinations of NEFA and BHBA concentrations. When used alone, none of the concentrations of BHBA inhibited DNA synthesis or IgM secretion. CONCLUSIONS AND CLINICAL RELEVANCE: Reduced immunoresponsiveness during ketosis is likely to be associated with an increase in plasma concentration of NEFA and not with an increase in plasma concentration of BH BA.  相似文献   

Effects on functions of ovine blood mononuclear cells for each of several fatty acids at concentrations found in plasma of healthy and ketotic ewes     

Lacetera N  Franci O  Scalia D  Bernabucci U  Ronchi B  Nardone A 《American journal of veterinary research》2002,63(7):958-962

OBJECTIVE: To assess effects on functions of peripheral blood mononuclear cells (PBMC) obtained from ewes for each of several fatty acids represented in ovine plasma at concentrations mimicking those of ketotic or healthy ewes. SAMPLE POPULATION: Blood samples obtained from 6 Sardinian ewes. PROCEDURE: The PBMC were cultured in media that contained oleic (OA), palmitic (PA), stearic (SA), linoleic (LA), or palmitoleic (POA) acid at concentrations similar to those of ketotic or healthy ewes. Synthesis of DNA was stimulated by use of concanavalin A or pokeweed mitogen (PWM). Secretion of IgM was stimulated by use of PWM. RESULTS: High concentrations (900, 450, and 225 micromol/L) of OA significantly inhibited DNA synthesis and IgM secretion of PBMC. Conversely, low concentrations (56 or 28 micromol/L) of OA significantly enhanced DNA synthesis of PBMC. High concentrations of PA (600, 300, 150, 75, 375, or 18.7 micromol/L) and SA (300, 150, or 75 micromol/L) significantly inhibited DNA synthesis of PBMC. High concentrations of PA (600, 300, 150, 75, 375, or 18.7 micromol/L) and SA (300, 150, 75, or 38 micromol/L) also significantly inhibited IgM secretion of PBMC. None of the concentrations of LA and POA affected PBMC functions. CONCLUSION AND CLINICAL RELEVANCE: Impaired immunoresponsiveness of ketotic ewes is likely associated with an increase of plasma concentrations of OA, PA, or SA and not with that of LA or POA. At physiologic concentrations, single fatty acids are likely to participate in modulation of immunoresponsiveness by exerting suppressive or stimulatory effects on immune cells.  相似文献   

Evaluation of different protein sources in fingerling grey mullet <Emphasis Type="Italic">Mugil cephalus</Emphasis> practical diets     

Umberto?Luzzana  Franco?ValfrèEmail author  Marco?Mangiarotti  Cinzia?Domeneghini  Giuseppe?Radaelli  Vittorio Maria?Moretti  Marco?Scolari 《Aquaculture International》2005,13(4):291-303

An eight-week experiment was carried out to evaluate the effects of different protein sources (fish and haemoglobin meal, soybean meal and torula yeast), in practical diets, on growth, body composition and gut morphology of fingerling grey mullet (Mugil cephalus). Weight gain (%), SGR, FCR, N retention, PER, PGR, FDR and carcass composition of fish were not significantly affected by the dietary protein source. Fish fed the torula yeast based diet showed reduction in growth performance. Histological examinations performed on the alimentary tract of the fish showed a normal structural pattern in the experimental groups, as fundamental histological and histochemical aspects were similar if compared to the control group. The lower growth performance observed in fish fed a torula yeast based diet may be tentatively correlated with the presence of some detrimental morpho-functional aspects in the gut of these fish if compared to fish fed the other diets. Further studies are necessary to confirm this hypothesis.  相似文献   

A modelling approach to infer the effects of wind farms on landscape connectivity for bats     

Federica Roscioni  Hugo Rebelo  Danilo Russo  Maria Laura Carranza  Mirko Di Febbraro  Anna Loy 《Landscape Ecology》2014,29(5):891-903

Little is known about the potentially disrupting effects of wind farms on the habitat connectivity of flying vertebrates at the landscape scale. We developed a regional-scale model to assess the wind farm impact on bat migration and commuting routes. The model was implemented for the bat Nyctalus leisleri in a region of central Italy currently undergoing considerable wind farm development. A Species Distribution Model (SDM) for N. leisleri was generated using the MaxEnt algorithm based on 47 presence records (reduced to 19 after the autocorrelation procedure) and 10 environmental variables derived from topographic and land cover maps. We used the SDM to create a map of connectivity using the software UNICOR to identify potential commuting corridors (PCCs). The incidence of each wind farm on bat flight corridors was assessed by overlaying the existing (380) and planned (195) turbine locations onto the PCCs. The SDM was statistically robust (AUC > 0.8). Most of the corridors were concentrated in the western part of the region, which hosts the largest suitable areas for the species; most of the existing (54 %) and planned (72 %) wind farms interfered with important corridors connecting the western and the eastern parts of the region. Our results provide key information on the impact of the wind farm industry on biodiversity on a regional scale. The novel approach adopted, based on SDM and connectivity analysis, could be easily extended to other flying vertebrates and landscapes and constitutes a promising planning tool necessary for harmonizing the development of renewable energy infrastructures with issues of biodiversity conservation.  相似文献   

Phytotoxic Effect of the Uranium on the Growing Up and Development the Plant of Corn     

Mirjana D. Stojanović  Dragi R. Stevanović  Jelena V. Milojković  Mirko S. Grubišić  Deana A. Ileš 《Water, air, and soil pollution》2010,209(1-4):401-410

The aim of this article is the determination of uranium accumulation in plants tissue in shoots and roots of corn—maize (Zea mays), grown on two types of soils, pseudogley and chernozem, together with its phytotoxic effect on the plant growth and development. The soils was contaminated with different rates (10 to 1,000 mg U(VI) kg^?1) of uranyl nitrate (UO₂(NO₃)₂·6H₂O). Vegetative tests performed with maize indicated uranium phytotoxic effect on plant height, yield, and germination of seeds. This effect was stronger on the plants grown on pseudogley in comparison with those grown on chernozem. Soil properties determined the tolerance and accumulation of U in plants. A linear dependence between the content of uranium in soil and in plants tissue, including maximal content of 1,000 mg U?kg^?1, indicates that maize could be used for phytoremediation of uranium-contaminated soils.  相似文献