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排序方式: 共有86条查询结果,搜索用时 15 毫秒
1.
The composition of arbuscular mycorrhizal fungi (AMF) communities found in agricultural systems has been found to be very different to that of forest. The implications of this, if any, for the restoration of indigenous forest on ex-agricultural land is poorly understood. This study investigated the effect that AMF communities isolated from ex-agricultural and forest soils have on the growth of an indigenous New Zealand tree species (Podocarpus cunninghamii). The forest AMF community was isolated from a remnant stand of P. cunninghamii forest and the ex-agricultural AMF from a retired grazing grassland. In addition, the study examined how the two AMF communities affected the competitiveness of P. cunninghamii when grown in competition with an invasive grass species (Agrostis capillaris), which is frequently dominant on ex-agricultural land in New Zealand. P. cunninghamii growth was significantly decreased by inoculation with ex-agricultural AMF compared to forest AMF. Furthermore, the forest AMF community was able to significantly increase P. cunninghamii root production when in competition with A. capillaris. The findings suggest that when attempting to restore indigenous forest on ex-agricultural land, inoculation of tree seedlings with appropriate forest AMF may improve their growth and survival. 相似文献
2.
黄瓜花叶病毒外壳蛋白质进入叶绿体与症状发生的关系 总被引:7,自引:0,他引:7
由感染黄瓜花叶病毒(CMV)、健康和转外壳蛋白(CP)基因的烟叶以原生质体法制备纯化的叶绿体。经SDS-PAGE电泳,银染色,比较其蛋白质图谱。用CMV外壳蛋白游离亚基制备的抗血清进行Western blotting。结果发现:1.CP存在于CMV侵染的烟叶绿体中。2.叶绿体中CP的浓度和花叶症状严重程度呈正相关;3.表达CP的转基因烟草叶绿体中未测出CP存在。根据以上结果,认为CMV侵染的烟花叶症状产生与CP进入叶绿体有直接相关性。 相似文献
3.
Effect of immunosuppressive doses of cyclosporine on pancreatic beta cell function in pigs 总被引:1,自引:0,他引:1
Dean SK Scott H Keogh GW Roberts S Tuch BE 《American journal of veterinary research》2002,63(11):1501-1506
OBJECTIVE: To evaluate whether immunosuppressive doses of cyclosporine (CsA) have an adverse effect on the liver, kidney, and pancreatic beta cells of pigs. ANIMALS: 8 juvenile 8-week-old Landrace X Large White crossbred pigs. PROCEDURE: CsA (100 to 140 mg/kg) was administered orally to euglycemic pigs to reach whole blood trough concentrations of approximately 1500 ng/mL. To determine pancreatic beta cell function, plasma C-peptide and insulin concentrations were measured in response to i.v. administration of glucose, glucagon, arginine, and oral administration of glucose. Effects on liver and kidney were determined by monitoring serum measurements of liver function and serum creatinine concentrations, respectively. RESULTS: Plasma concentrations of C-peptide were significantly lower in euglycemic CsA-treated pigs, compared with control pigs, following i.v. administration of glucose, glucagon, arginine, and oral administration of glucose. Furthermore, the glucose clearance rate was decreased in euglycemic CsA-treated pigs, compared with control pigs. Serum creatinine concentrations and 4 of 7 serum measurements of liver function were not adversely affected by CsA administration. Serum concentrations of bilirubin and albumin were significantly increased, and serum alanine aminotransferase activity was significantly decreased in CsA-treated pigs, compared with control pigs. Histologic evaluation of liver and kidney sections revealed no pathologic findings in CsA-treated or control pigs. CONCLUSIONS AND CLINICAL RELEVANCE: In our study, immunosuppressive doses of CsA caused an impairment of porcine pancreatic beta cell function, but did not have toxic effects on the kidney. However, on the basis of changes in serum bilirubin and albumin concentrations and alanine aminotransferase activity, subclinical toxic effects on the liver did occur when immunosuppressive doses of CsA were administered. 相似文献
4.
Hayley Weston Murphy Michele Miller Jan Ramer Dominic Travis Robyn Barbiers Nathan D Wolfe William M Switzer 《Journal of zoo and wildlife medicine》2006,37(3):219-233
Nonhuman primates can be naturally infected with a plethora of viruses with zoonotic potential, including retroviruses. These simian viruses present risks to both captive nonhuman primate populations and persons exposed to nonhuman primates. Simian retroviruses, including simian immunodeficiency virus, simian type D retrovirus, simian T-lymphotropic virus, and gibbon ape leukemia virus, have been shown to cause clinical disease in nonhuman primates. In contrast, simian foamy virus, a retrovirus that is highly prevalent in most nonhuman primates, has not been associated with clinical disease in naturally infected primates. Although it has been shown that human retrovirus infections with human T-lymphotropic virus and human immunodeficiency virus originated through multiple independent introductions of simian retroviruses into human populations that then spread globally, little is known about the frequency of such zoonotic events. In this article, exogenous simian retroviruses are reviewed as a concern for zoo and wildlife veterinarians, primate handlers, other persons in direct contact with nonhuman primates, and other nonhuman primates in a collection. The health implications for individual animals as well as managed populations in zoos and research institutions are discussed, the cross-species transmission and zoonotic disease potential of simian retroviruses are described, and suggestions for working safely with nonhuman primates are provided. 相似文献
5.
Habitat use by the African anabantid fish Ctenopoma muriei: implications for costs of air breathing 总被引:1,自引:1,他引:0
Abstract – This study examined whether habitat use by the African anabantid fish Ctenopoma muriei is consistent with predictions relating to two costs of air breathing (surface travel and aerial predation). We predicted that C. muriei would be most abundant in habitats that minimize potential costs of air breathing. We quantified environmental correlates of C. muriei abundance within a series of wetland lagoons in Uganda and found that C. muriei was more abundant in shallow waters of the deepest lagoon, in vegetated habitats, and at a depth 15–30 cm below the surface. These locations may minimize cost of travel to the surface for aerial respiration, while maintaining a reasonable distance from the surface to avoid detection by aerial predators. In addition, we experimentally tested effectiveness of vegetative cover in reducing mortality of C. muriei by aerial predators (pied kingfishers) using enclosures with and without vegetation cover in a swamp pool. We found that the presence of vegetative cover significantly reduced susceptibility of C. muriei to predation by pied kingfishers when dissolved oxygen in the water was low and air-breathing frequency was potentially high. 相似文献
6.
7.
Drosou Konstantina Craig Hayley Palmer Karren Kennedy Sandra L. Wishart John Oliveira Hugo R. Civáň Peter Martin Peter Brown Terence A. 《Genetic Resources and Crop Evolution》2022,69(7):2361-2381
Genetic Resources and Crop Evolution - We used genotyping-by-sequencing to investigate the evolutionary history of bere, the oldest barley variety still cultivated in Britain and possibly in all of... 相似文献
8.
Johanna Steyaert Travis Glare Alison Stewart Margaret Carpenter Hayley Ridgway 《浙江大学学报(农业与生命科学版)》2004,30(4):442-442
Achieving a balance between vegetative growth and spore production is essential for successful biocontrol by fungi. Low sporulation rates in the field can result in poor establishment and survival,whereas failure of conidia to recognise hosts can lead to persistence without efficacy. Commercial biocontrol products involve bulk preparations of conidia, however considerable variability in conidiation rates exists between biocontrol agents, which can restrict choice of strain for production. The majority of studies on Trichoderma conidiation have focused on the species T. viride and T. atroviride.These species form conidia in response to blue and near-UV light and/or nutrient deprivation and conidiation proceeds in a highly co-ordinated fashion, however relatively little is known on the genetic basis of Trichoderrma conidiation. In addition, whilst photoconidiation appears to be a general response detailed studies in other Trichoderma species are absent. In this study, conidiation in the lesser known biocontrol species T. hamatum is being investigated using a combined morphological and molecular approach. In contrast to T. atroviride, conidiation in response to blue-light was weaker and variable and suggested that additional triggers may be required for the T. hamatum photoresponse. A series of comparative photoconidiation assays are currently being undertaken investigating the effect of inoculum type and abiotic factors on timing and intensity of the response.Results will be discussed in relation to the current knowledge on conidial morphogenesis in Trichoderma. In addition to these morphological assays, a selection of genes implicated in sporulation and the blue-light responses are currently being isolated and characterised from T. hamatum. Two genes, phr1 and cmp1 , which were isolated previously from T. atroviride will be used as early and late markers of gene expression during the photoresponse in T. hamatum in order to define time points for harvesting comparable stage-specific RNA from T. hamatum and T. atroviride. Using degenerate PCR putative sporulation gene orthologues have also been identified in T. hamatum.Work is currently underway to isolate genomic clones of these genes from T. hamatum and T.atroviride. Sequence and expression analysis of orthologues, including expression in response to abiotic factors will be presented and discussed in relation to the current knowledge of the molecular basis of conidiation in Trichoderma and other filamentous fungi.…… 相似文献
9.
Shimojima M Miyazawa T Ikeda Y McMonagle EL Haining H Akashi H Takeuchi Y Hosie MJ Willett BJ 《Science (New York, N.Y.)》2004,303(5661):1192-1195
Feline immunodeficiency virus (FIV) induces a disease similar to acquired immunodeficiency syndrome (AIDS) in cats, yet in contrast to human immunodeficiency virus (HIV), CD4 is not the viral receptor. We identified a primary receptor for FIV as CD134 (OX40), a T cell activation antigen and costimulatory molecule. CD134 expression promotes viral binding and renders cells permissive for viral entry, productive infection, and syncytium formation. Infection is CXCR4-dependent, analogous to infection with X4 strains of HIV. Thus, despite the evolutionary divergence of the feline and human lentiviruses, both viruses use receptors that target the virus to a subset of cells that are pivotal to the acquired immune response. 相似文献
10.
Nicholas T. Amponsah E. Eirian Jones Hayley J. Ridgway Marlene V. Jaspers 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(3):467-482
This study investigated the prevalence and identity of botryosphaeriaceous dieback pathogens in necrotic grapevines tissues
in New Zealand vineyards, and other woody hosts growing nearby. The presumptive identities of the isolates by conidial and
cultural morphology were confirmed with ITS sequence data as Neofusicoccum australe, N. luteum, N. parvum and Diplodia seriata. They were isolated predominantly from necrotic stems of grapevine and other hosts, but also from leaves, flowers and wood
debris of grapevines. Inoculation with conidia and mycelium of multiple isolates of each species onto excised and attached
green shoots and trunks of five grapevine varieties, Cabernet sauvignon, Chardonnay, Pinot noir, Riesling, and Sauvignon blanc,
showed that all varieties became infected to a similar extent. All species except D. seriata were pathogenic, irrespective of the host source, with N. luteum being the most and D. mutila the least pathogenic (P < 0.05). On trunks, N. parvum caused cankers and the other pathogenic species caused die-back when the inoculated vines became winter-dormant. Conidia
were produced from green shoot lesions and die-back wood, which indicates potential inoculum sources for vineyard infection. 相似文献