排序方式： 共有92条查询结果，搜索用时 636 毫秒
61.
Bayram O Krappmann S Ni M Bok JW Helmstaedt K Valerius O Braus-Stromeyer S Kwon NJ Keller NP Yu JH Braus GH 《Science (New York, N.Y.)》2008,320(5882):1504-1506
Differentiation and secondary metabolism are correlated processes in fungi that respond to light. In Aspergillus nidulans, light inhibits sexual reproduction as well as secondary metabolism. We identified the heterotrimeric velvet complex VelB/VeA/LaeA connecting light-responding developmental regulation and control of secondary metabolism. VeA, which is primarily expressed in the dark, physically interacts with VelB, which is expressed during sexual development. VeA bridges VelB to the nuclear master regulator of secondary metabolism, LaeA. Deletion of either velB or veA results in defects in both sexual fruiting-body formation and the production of secondary metabolites. 相似文献
62.
Susanna Sternberg Karin Bernodt Andrea Holmstr?m Bengt R?ken 《Journal of zoo and wildlife medicine》2002,33(4):378-380
Tuberculin test results from 214 animals in three Swedish zoos, tested between the years 1993 and 2000, were compiled from a questionnaire sent out to zoo veterinarians. Comparative testing with bovine and avian tuberculin was used on various sites of injection. A total of five skin test reactors were found: three cotton-top tamarins (Saguinus oedipus) in one zoo and two tapirs (Tapirus terrestris) in another zoo. Postmortem culture from one of the tapirs revealed growth of Mycobacterium tuberculosis, and a stamping out policy was adopted in the herd. Tuberculosis in the primates was ruled out by further investigations. Zoo veterinarians should try to adopt a common scheme for the regular testing of zoo animals to improve the diagnostic ability and comparison of results between institutions. 相似文献
63.
Jensen GM Frydendahl K Svendsen O Jørgensen CB Cirera S Fredholm M Nielsen JP Møller K 《Veterinary microbiology》2006,115(1-3):243-249
The outcome of experimental intestinal infections with enterotoxigenic Escherichia coli (ETEC) is dependent on several factors. An important factor is adhesion of the challenge strain to the intestinal mucosa. The test for susceptibility towards ETEC adhesion has so far been made by an intestinal adhesion test made after slaughter of piglets. However, in an experimental infection study with the purpose to obtain diarrhoeic piglets, it would be an advantage to test for susceptibility prior to experimentation. The Mucin 4 gene on porcine chromosome 13 has been proposed as a candidate gene for the production of the specific ETEC F4ab/ac receptor, and a DNA marker-based test has been developed to allow genotyping for ETEC F4ab/ac resistance/susceptibility [J?rgensen, C.B., Cirera, S., Archibald, A.L., Anderson, L., Fredholm, M., Edfors-Lilja, I., 2004. Porcine polymorphisms and methods for detecting them. International application published under the patent cooperation treaty (PCT). PCT/DK2003/000807 or WO2004/048606-A2]. The aim of this study was to test an experimental model for ETEC O149:F4ac-induced diarrhoea in piglets, selected for susceptibility towards ETEC O149:F4ac adhesion prior to experimentation using a DNA marker-based test. Sixty-two healthy 25-32 days old recently weaned Danish crossbred piglets were used. All piglets were tested prior to experimentation for susceptibility or resistance towards ETEC O149:F4ac adhesion. Thirty-nine piglets, both susceptible and resistant, were oro-gastric intubated with 10(9)CFU of ETEC O149:F4ac and 23 age-matched piglets, both susceptible and resistant, were used as non-infected controls. Of susceptible piglets, challenged with ETEC O149:F4ac, 74% had ETEC O149:F4ac-associated diarrhoea first day after first challenge, which were significantly higher relatively to the resistant and challenged piglets where 20% had diarrhoea (p=0.04). This study suggests a model for experimental ETEC induced diarrhoea. 相似文献
64.
Terszowski G Müller SM Bleul CC Blum C Schirmbeck R Reimann J Pasquier LD Amagai T Boehm T Rodewald HR 《Science (New York, N.Y.)》2006,312(5771):284-287
The thymus organ supports the development of T cells and is located in the thorax. Here, we report the existence of a second thymus in the mouse neck, which develops after birth and grows to the size of a small lymph node. The cervical thymus had a typical medulla-cortex structure, was found to support T cell development, and could correct T cell deficiency in athymic nude mice upon transplantation. The identification of a regular second thymus in the mouse may provide evolutionary links to thymus organogenesis in other vertebrates and suggests a need to reconsider the effect of thoracic thymectomy on de novo T cell production. 相似文献
65.
Kariluoto S Liukkonen KH Myllymäki O Vahteristo L Kaukovirta-Norja A Piironen V 《Journal of agricultural and food chemistry》2006,54(25):9522-9528
Effects of germination conditions and thermal processes on folate contents of rye were investigated. Total folate contents were determined microbiologically with Lactobacillus rhamnosus (ATCC 7469) as the growth indicator organism, and individual folates were determined by high-performance liquid chromatography after affinity chromatographic purification. Germination increased the folate content by 1.7-3.8-fold, depending on germination temperature, with a maximum content of 250 micro g/100 g dry matter. Hypocotylar roots with their notably high folate concentrations (600-1180 micro g/100 g dry matter) contributed 30-50% of the folate contents of germinated grains. Germination altered the proportions of folates, increasing the proportion of 5-methyltetrahydrofolate and decreasing the proportion of formylated folate compounds. Thermal treatments (extrusion, autoclaving and puffing, and IR and toasting) resulted in significant folate losses. However, folate levels in grains that were germinated and then were heat processed were higher than for native (nongerminated) grains. Opportunities to optimize rye processing to enhance folate levels in rye-based foods are discussed. 相似文献
66.
Susanna Laaksonen-Craig 《Journal of Sustainable Forestry》2013,32(1-2):172-188
ABSTRACT The paper examines the relationships between the inflow of foreign direct investment (FDI) in the forestry and forest products industry and host-country-specific factors that affect the spatial distribution of FDI. Data on Brazil and Chile are used to analyze the impact of market size, roundwood supply, and exports on FDI. The results indicate that the main motivation for FDI is market-seeking and resource-seeking, highlighting the role of domestic demand and sufficient supply of roundwood in multinational forestry companies' investment decisions. The results further imply that governments can use policies related to these factors to attract foreign investment into the forest sector in Brazil and Chile. 相似文献
67.
OBJECTIVE: The aim of this study was to examine whether there are associations between working conditions and the use of staff canteen or packed meals among Finnish employees. SETTING: Data were obtained from cross-sectional surveys on working conditions, conducted triennially (1997, 2000, 2003) since 1997. SUBJECTS: In each survey, the subjects were 25-64-year-old employed Finnish employees: 3096 men and 3273 women. RESULTS: Employees at large workplaces used canteens far more often than those at smaller workplaces. Working conditions played a different role in canteen use at small and large workplaces, as well as among the different sexes. At small workplaces, physically demanding jobs held by female employees and low job control encouraged employees to use the canteen. On the other hand, at large workplaces, low social support at work encouraged the use of canteens among men whereas high mental strain at work meant they used the canteen less. Among women, eating packed meals was not related to working conditions, but among men, low social support and high mental strain at work were associated with more frequent use of packed meals. CONCLUSIONS: The use of a staff canteen is largely determined by the size of the workplace and by employee education. The underlying factor could be the availability of canteens, a question which must be confirmed in further studies, since well-planned mass catering at workplaces has major effects on public health, well-being and the nutrition education of employees. 相似文献
68.
Stefania Galletti Eleonora Sala Onofrio Leoni Susanna Cinti Claudio Cerato 《Soil biology & biochemistry》2008,40(9):2170-2173
Biofumigation is a biocontrol method that uses volatile compounds to combat soil pathogens. We investigated a biofumigation process based on the green manure of Brassicaceae. These plants contain the glucosinolate-myrosinase system which releases inhibitory compounds such as isothiocyanate into the soil. However, the biocontrol effectiveness is often lower than expected, possibly due to microbial transformation of the isothiocyanates. In order to identify the possible function of microorganisms, their interaction with glucosinolates and glucosinolate-derived products was investigated. We report the ability of a soil isolate of Aspergillus flavus to grow in liquid culture and convert 2-propenyl and 2-phenylethyl glucosinolate and their desulfo-derivatives, to nitriles. This finding would suggest the existence of an arylsulfatase and a β-thio-glucosidase, different from myrosinase, which could direct glucosinolate conversion in soil towards nitriles rather than isothiocyanates. If confirmed in soil, our observations could at least partially explain the low concentrations of isothiocyanates after biofumigation. 相似文献
69.
Susanna Gomez Orndorff Jehangir Hoshang Bhadha James Mabry McCray Samira Hassan Daroub 《Journal of plant nutrition》2018,41(7):928-942
Agricultural by-products applied as soil amendments have the potential to improve crop production on low organic matter (OM) soils. This two-year study investigated the use of two readily available sugarcane (Saccharum spp.) milling by-products, mill mud, and mill ash, as soil amendments to improve first sugarcane crop (plant cane) and subsequent crop (first ratoon) grown on a sandy Spodosol. Sugarcane was grown in lysimeters receiving mill mud, mill ash, and a 50:50 (v:v) mill mud to mill ash mix. Amendments were applied at low, medium, and high application rates (5, 10, and 15 cm depths, respectively) and then incorporated 30 cm deep. Amendment effects on plant nutrition, soil characteristics, and crop yield were determined. High rate applied mill mud and mill ash had the highest soil OM content for both years and soil OM did not significantly change between crops for all treatments except for high rate mill mud, which increased the second year (ratoon crop). Leaf nutrient levels for nitrogen (N), iron (Fe), and copper (Cu) for all treatments both years were insufficient; nutrient levels for magnesium (Mg), manganese (Mn), and silicon (Si) were within marginal to sufficient range for all treatments both years. All amendments produced significantly higher biomass and sucrose yields for plant cane and first ratoon crops compared to the control. Mill ash treatments produced the greatest increase in sucrose and biomass yields from plant cane to ratoon crops, which corresponded with an increase in potassium (K) in leaf tissue. However, mid and high rates of mix produced the highest sugarcane biomass and sucrose yields for the both the plant cane and ratoon crops. 相似文献
70.