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991.
992.
Mapping of Fhb2 on chromosome 6BS: a gene controlling Fusarium head blight field resistance in bread wheat (Triticum aestivum L.) 总被引:4,自引:0,他引:4
Cuthbert PA Somers DJ Brulé-Babel A 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(3):429-437
Fusarium head blight (FHB) is one of the most important fungal wheat diseases worldwide. Understanding the genetics of FHB
resistance is key to facilitate the introgression of different FHB resistance genes into adapted wheat. The objective of this
project was to study the FHB resistance QTL on chromosome 6B, quantify the phenotypic variation, and qualitatively map the
resistance gene as a Mendelian factor. The FHB resistant parent BW278 (AC Domain*2/Sumai 3) was used as the source of the
resistance allele. A large recombinant inbred line (RIL) mapping population was developed from the cross BW278/AC Foremost.
The population segregated for three known FHB resistance QTL located on chromosomes 3BSc, 5A, and 6B. Molecular markers on
chromosome 6B (WMC104, WMC397, GWM219), 5A (GWM154, GWM304, WMC415), and 3BS (WMC78, GWM566, WMC527) were amplified on approximately
1,440 F2:7 RILs. The marker information was used to select 89 RILs that were fixed homozygous susceptible for the 3BSc and 5A FHB QTLs
and were recombinant in the 6B interval. Disease response was evaluated on 89 RILs and parental checks in the greenhouse and
field nurseries. Dual floret injection (DFI) was used in greenhouse trials to evaluate disease severity (DS). Macroconidial
spray inoculations were used in field nurseries conducted at two locations in southern Manitoba (Carman and Glenlea) over
two years 2003 and 2004, to evaluate disease incidence, disease severity, visual rating index, and Fusarium-damaged kernels.
The phenotypic distribution for all five-disease infection measurements was bimodal, with lines resembling either the resistant
or susceptible checks and parents. All of the four field traits for FHB resistance mapped qualitatively to a coincident position
on chromosome 6BS, flanked by GWM133 and GWM644, and is named Fhb2. The greenhouse-DS trait mapped 2 cM distal to Fhb2. Qualitative mapping of Fhb2 in wheat provides tightly linked markers that can reduce linkage drag associated with marker assisted selection of Fhb2 and aid the pyramiding of different resistance loci for wheat improvement. 相似文献
993.
Parasitism of Tuta absoluta (Lepidoptera, Gelechiidae) by Pseudapanteles dignus (Hymenoptera, Braconidae) under laboratory conditions 总被引:1,自引:0,他引:1
Laboratory studies were conducted to measure selected life history traits and the functional response of the parasitoid Pseudapanteles dignus (Muesebeck), a major enemy of Tuta absoluta (Meyrick) in tomato crops in South America. Newly mated P. dignus females were individually exposed to 10 host larvae in mines for 24 h. We determined developmental time from egg to pupal formation and pupal stage duration, female adult life span, fecundity, reproductive period, daily parasitism rate, and sex ratio of offspring. For the functional response experiment, treatments consisted of six host densities: 3, 5, 7, 10, 15, 20, or 30 larvae. The number and proportion of parasitized hosts were calculated for each density. The shape of the functional response curve was analyzed by logistic regression. P. dignus females attacked hosts daily, exhibiting modest lifetime fecundity (approximately 32 parasitized hosts per female) and a female-biased offspring sex ratio. Female adult life span was 36 d. P. dignus showed a type I functional response within the range of host densities tested. We observed that females detect and parasitize the host within a wide range of densities, including low densities. The functional response curve reached an asymptote at a mean density of six hosts per day and seemed not to be egg-limited. Percent parasitism was approximately 30%. The ecological implications of the results in relation to the potential of P. dignus for the biological control of T. absoluta in tomato are discussed. 相似文献
994.
We examined flight activity patterns for a guild of fire ant parasitoids in western Argentina in relationship to their host's location (mound/foraging trail) and light condition (full sun/partial sun/full shade) at different scales, from the individually sampled mound to the full day's summation for each species. We asked first whether taxa showed preferences among these conditions, and second, whether certain species and sexes might be found together more frequently than expected to by chance. All species, except the P. obtusus species complex, were significantly more likely to be found attacking ants at disturbed mounds than at paired foraging trails. The P. nocens complex and P. litoralis were more likely to be in the shade when temperatures were above the overall mean of the study (28.3 degrees C), whereas others, such as the P. obtusus complex and P. tricuspis, were more likely to be in full sun under these same conditions. Our analyses indicated that a limited set of species, particularly P. nocens with P. litoralis, and males with female P. obtusus and P. tricuspis, were more likely to be found together than expected. We also found decreasing proportions of males with increasing time of analysis. We discuss the implications of host location, metereological conditions, and sex ratios in relationship to ongoing classical biological control efforts using species of these phorids. 相似文献
995.
Magalhães GF Nogueira PA Grava AF Penati M Silva LH Orlandi PP 《Memórias do Instituto Oswaldo Cruz》2007,102(5):555-557
Acute gastroenteritis is one of the most common diseases in humans worldwide. Viral gastroenteritis is a global problem in infants and young children. In this study the incidence of diarrhea was assessed in 877 hospitalized children under five years old, over a period of 24 months and distributed in 470 cases of diarrhea and 407 age-matched group with other pathologies, as control group. Two antigen detection techniques based on enzyme immunoassay (EIA) and latex particles were used for detection of rotavirus and adenovirus. Rotavirus A was a major cause of gastroenteritis with 23.6% of cases, being 90% of these cases in young children. Adenovirus infections was detected by EIA with frequency of 6.4%. Rotavirus and adenovirus were detected in 10.1 and 1.7% of stools from control group, respectively. Interestingly, the frequency of the youngest children in the control group excreting Rotavirus A was comparable to that detected in stools from diarrheic children. We cannot rule out the existence of other enteric viruses because the etiology of 171 cases of diarrhea was not determined and active search for astrovirus and calicivirus was not done. This is the first study that shows the presence of enteric viruses in the infantile population from Western Brazilian Amazonia and it was important to help physicians in the treatment of viral gastroenteritis. 相似文献
996.
Patrick AL Rullo J Beaudin S Liaw P Fox-Robichaud AE 《American journal of physiology. Gastrointestinal and liver physiology》2007,293(4):G663-G672
The development of chronic liver diseases is mediated by sustained hepatic inflammation. Our objective was to characterize the molecular mechanisms responsible for the hepatic inflammatory response to time-limited TNF-alpha and IL-1beta expression. C57Bl/6 mice were injected with 2 x 10(7) plaque forming units intraperitoneally of an adenoviral vector containing TNF-alpha or IL-1beta (AdTNF-alpha or AdIL-1beta). A nonreplicating adenoviral vector served as control. Four days later, under ketamine and xylazine anesthesia, the liver microvasculature was examined by intravital microscopy. In the postsinusoidal venules, leukocyte rolling increased significantly in response to both AdTNF-alpha and AdIL-1beta, compared with controls. This response was significantly reduced following injection of an anti-alpha4-integrin monoclonal antibody (MAb). Postsinusoidal rolling was further reduced to baseline following injection of an anti-P-selectin or anti-L-selectin MAb. Sinusoidal adhesion was greater in mice treated with AdIL-1beta than with AdTNF-alpha. Blocking alpha4-integrin, P-selectin, or L-selectin had no significant effect on sinusoidal or postsinusoidal adhesion. In separate experiments, we administered AdTNF-alpha or AdIL-1beta to mice deficient in ICAM-1. In ICAM-1-/- mice, postsinusoidal leukocyte rolling significantly increased following expression of IL-1beta but not TNF-alpha. AdIL-1beta- but not AdTNF-alpha-mediated sinusoidal adhesion was ICAM-1 dependent. AdTNF-alpha-induced sinusoidal adhesion was significantly reduced following 4 days of anti-MIP-2 MAb and anti-KC MAb. Prolonged expression of the cytokines TNF-alpha and IL-1beta increases hepatic leukocyte-endothelial cell interactions. Interestingly, the mechanisms through which these cytokines bring about adhesion within the sinusoids differ; AdIL-1beta sinusoidal adhesion uses an ICAM-1-dependent mechanism whereas AdTNF-alpha-mediated adhesion is ICAM-1 independent but CXC chemokine dependent. 相似文献
997.
<Emphasis Type="Italic">Bacillus megaterium</Emphasis>—from simple soil bacterium to industrial protein production host 总被引:2,自引:0,他引:2
Vary PS Biedendieck R Fuerch T Meinhardt F Rohde M Deckwer WD Jahn D 《Applied microbiology and biotechnology》2007,76(5):957-967
Bacillus megaterium has been industrially employed for more than 50 years, as it possesses some very useful and unusual enzymes and a high capacity
for the production of exoenzymes. It is also a desirable cloning host for the production of intact proteins, as it does not
possess external alkaline proteases and can stably maintain a variety of plasmid vectors. Genetic tools for this species include
transducing phages and several hundred mutants covering the processes of biosynthesis, catabolism, division, sporulation,
germination, antibiotic resistance, and recombination. The seven plasmids of B. megaterium strain QM B1551 contain several unusual metabolic genes that may be useful in bioremediation. Recently, several recombinant
shuttle vectors carrying different strong inducible promoters and various combinations of affinity tags for simple protein
purification have been constructed. Leader sequences-mediated export of affinity-tagged proteins into the growth medium was
made possible. These plasmids are commercially available. For a broader application of B. megaterium in industry, sporulation and protease-deficient as well as UV-sensitive mutants were constructed. The genome sequence of
two different strains, plasmidless DSM319 and QM B1551 carrying seven natural plasmids, is now available. These sequences
allow for a systems biotechnology optimization of the production host B. megaterium. Altogether, a “toolbox” of hundreds of genetically characterized strains, genetic methods, vectors, hosts, and genomic sequences
make B. megaterium an ideal organism for industrial, environmental, and experimental applications. 相似文献
998.
Kraft M Knüpfer U Wenderoth R Kacholdt A Pietschmann P Hock B Horn U 《Applied microbiology and biotechnology》2007,76(6):1413-1422
The functional analysis of individual proteins or of multiprotein complexes—since the completion of several genome sequencing
projects—is in focus of current scientific work. Many heterologous proteins contain disulfide-bonds, required for their correct
folding and activity, and therefore, need to be transported to the periplasm. The production of soluble and functional protein
in the periplasm often needs target-specific regulatory genetic elements, leader peptides, and folding regimes. Usually, the
optimization of periplasmic expression is a step-wise and time-consuming procedure. To overcome this problem we developed
a dual expression system, containing a degP-promoter-based reporter system and a highly versatile plasmid set. This combines the differential protein expression with
the selection of a target-specific expression plasmid. For the validation of this expression tool, two different molecular
formats of a recombinant antibody directed to the human epidermal growth factor receptor and human 11β-hydroxysteroid dehydrogenase
type 2 (11β-HSD2) were used. By application of this expression system we demonstrated that the amount of functional protein
is inversely proportional to the on-line luciferase signal. We showed that this technology offers a simple tool to evaluate
and improve the yield of functionally expressed proteins in the periplasm, which depends on the used regulatory elements and
folding strategies. 相似文献
999.
Ghia JE Blennerhassett P El-Sharkawy RT Collins SM 《American journal of physiology. Gastrointestinal and liver physiology》2007,293(4):G711-G718
The vagus nerve inhibits the response to systemic administration of endotoxin, and we have recently extended this observation to show that the vagus attenuates acute experimental colitis in mice. The purpose of the present study was to determine whether there is a tonic counterinflammatory influence of the vagus on colitis maintained over several weeks. We assessed disease activity index, macroscopic and histological damage, myeloperoxidase (MPO) activity, and Th1 and Th2 cytokine profiles in chronic colitis induced by administration of dextran sodium sulfate (DSS) in drinking water for three cycles during 5 days with 11 days of rest between each cycle (DSS 3, 2, 2%) in healthy and vagotomized C57BL/6 mice and in mice deficient in macrophage-colony stimulating factor (M-CSF). A pyloroplasty was performed in vagotomized mice. Vagotomy accelerated the onset and the severity of inflammation during the first and second but not the third cycle. Although macroscopic scores were not significantly changed, histological scores as well as MPO activity and colonic tissue levels of IL-1alpha, TNF-alpha, IFN-gamma, and IL-18 but not IL-4 were significantly increased in vagotomized mice compared with sham-operated mice that received DSS. In control mice (without colitis), vagotomy per se did not affect any inflammatory marker. Vagotomy had no effect on the colitis in M-CSF-derived macrophage-deficient mice. These results indicate that the vagus protects against acute relapses on a background of chronic inflammation. Identification of the molecular mechanisms underlying the protective role of parasympathetic nerves opens a new therapeutic avenue for the treatment of acute relapses of chronic inflammatory bowel disease. 相似文献
1000.
Identification of the IL-17 receptor related molecule IL-17RC as the receptor for IL-17F 总被引:2,自引:0,他引:2
Kuestner RE Taft DW Haran A Brandt CS Brender T Lum K Harder B Okada S Ostrander CD Kreindler JL Aujla SJ Reardon B Moore M Shea P Schreckhise R Bukowski TR Presnell S Guerra-Lewis P Parrish-Novak J Ellsworth JL Jaspers S Lewis KE Appleby M Kolls JK Rixon M West JW Gao Z Levin SD 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(8):5462-5473
The proinflammatory cytokines IL-17A and IL-17F have a high degree of sequence similarity and share many biological properties. Both have been implicated as factors contributing to the progression of inflammatory and autoimmune diseases. Moreover, reagents that neutralize IL-17A significantly ameliorate disease severity in several mouse models of human disease. IL-17A mediates its effects through interaction with its cognate receptor, the IL-17 receptor (IL-17RA). We report here that the IL-17RA-related molecule, IL-17RC is the receptor for IL-17F. Notably, both IL-17A and IL-17F bind to IL-17RC with high affinity, leading us to suggest that a soluble form of this molecule may serve as an effective therapeutic antagonist of IL-17A and IL-17F. We generated a soluble form of IL-17RC and demonstrate that it effectively blocks binding of both IL-17A and IL-17F, and that it inhibits signaling in response to these cytokines. Collectively, our work indicates that IL-17RC functions as a receptor for both IL-17A and IL-17F and that a soluble version of this protein should be an effective antagonist of IL-17A and IL-17F mediated inflammatory diseases. 相似文献