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951.
David White Weidong Chen 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):3-12
Ascochyta blight is a serious disease of cool-season grain legumes (chickpea, faba bean, lentil and pea) caused by fungal
species of the anamorphic genus Ascochyta and related genera. Despite extensive studies on the biology, ecology, epidemiology
and management of the disease, little is known about the pathogenic determinants of these pathogens. This research aims at
using Ascochyta rabiei as a model for the genus in investigating genetic factors of pathogenicity, with the ultimate goal of elucidating pathogenic
mechanisms. Three advances were made: (1) insertional mutants with altered pathogenicity were identified through in vivo screening,
and genomic regions adjacent to the insertion sites in selected mutants were determined; (2) a phage library of A. rabiei genomic DNA was constructed, and the library was estimated to provide complete coverage of the A. rabiei genome. This library was used successfully to recover clones with DNA adjacent to insertional mutation sites and to isolate
specific genes; (3) DNA probes specific for an acyl-CoA ligase (cps1) and a polyketide synthase gene (pks1) were developed and library clones containing the corresponding genomic regions were identified from the phage library.
These advances provide the foundation and necessary tools for experimentation of ectopic complementation assays and targeted
mutagenesis to elucidate the genetic mechanisms of pathogenicity of A. rabiei. 相似文献
952.
Effects of water table management on soil salinity and alfalfa yield in a semi-arid climate 总被引:2,自引:0,他引:2
Hamideh Noory Abdol-Majid Liaghat Mohamad Reza Chaichi Masoud Parsinejad 《Irrigation Science》2009,27(5):401-407
A lysimeter experiment was conducted to investigate the effect of water table management (WTM) on distribution of soil salinity
and annual alfalfa (Medicago scutellata) yield. Subirrigations with three levels of water table namely, 0.5 (WT0.5), 0.7 (WT0.7), and 1.0 m (WT1.0) and a free drainage
(FD) conventional irrigation treatment were selected for this study. All treatments were arranged in a complete randomized
block design with three replicates. The results of this study indicated that the average soil electrical conductivity of the
saturated extract (ECe) in the root zone gradually increased and exceeded the designated crop threshold value (4 dS/m) after
the first forage harvest in subirrigated lysimeters. A higher salt accumulation was observed at the WT0.5 treatment. The average
dry matter yield of annual alfalfa in WT0.5 and WT0.7 treatments was found to be 52 and 73% higher compared with the control
treatment, respectively. 相似文献
953.
Anzai T Timoney JE Kuwamoto Y Wada R Oikawa M Higuchi T 《American journal of veterinary research》2002,63(9):1298-1301
OBJECTIVE: To develop polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis for molecular typing of strains of Streptococcus zooepidemicus and to use the new typing method to analyze a collection of isolates from the respiratory tract of Thoroughbreds. SAMPLE POPULATION: 10 strains of S zooepidemicus, 65 isolates from the respiratory tract of 9 yearlings following long distance transportation, and 89 isolates from tracheal aspirates of 20 foals with pneumonia. PROCEDURE: Phenotypic variations in the SzP protein were detected by western immunoblot analysis. Using PCR-RFLP analysis, genotypes were obtained with primer sets from the SzP gene, followed by restriction endonuclease digestion of the amplicons. RESULTS: Unique genotypic patterns were obtained with a primer set designed from both ends of the structural gene and the restriction endonuclease DdeI. Forty-five isolates from the lymphoid tissue within the pharyngeal recess (ie, pharyngeal tonsil) of yearlings included 10 SzP genotypes and SzP phenotypes. Isolates from the trachea of each yearling were of a single genotype that was also present among isolates from the pharyngeal tonsil of the same horses. Isolates from tracheal aspirates of foals belonged to 14 genotypes. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of the SzP gene by use of PCR-RFLP was effective for molecular typing of strains of S zooepidemicus in the study of respiratory tract disease in horses. Results of PCR-RFLP analysis indicate that a single strain of S zooepidemicus can migrate from the pharyngeal tonsil to the trachea at a high rate in horses undergoing long distance transportation. 相似文献
954.
A cost-effective method for producing and using recombinant growth hormone (GH) has been developed. A cell-surface protein
display system was constructed to produce recombinant Japanese flounder growth hormone (r-JfGH) in yeast Saccharomyces cerevisiae and the biological activity of expressed r-JfGH was evaluated by oral delivery to juvenile Japanese flounder. The expression
vector pYD-E2, containing the JfGH gene, S. cerevisiae GAL1 promoter, and the S.cerevisiae URA3 gene downstream and upstream sequences, was designed and constructed to integrate the GH gene into the yeast genome
and secrete r-JfGH stably on the surface of the yeast cell. Expression of r-JfGH was confirmed by flow cytometry until the
50th continuous generation of transgenic yeast strain y-E2, and over 0.98 μg r-JfGH per 1 mg total protein of y-E2 was estimated
by an ELISA–RA assay. Growth of Japanese flounder was promoted significantly by the direct supplementation of freeze-dried
transgenic yeast into the Japanese flounder juvenile feed at levels of 0.5 and 1%. The weight-specific growth rate and feed
conversion ratio of the treated groups were 23.07 and 21.57% (0.5% feeding level) and 28.85 and 41.18% (1% feeding level),
respectively, higher than that of the control group in a 7-week bioactivity study. 相似文献
955.
Md. Abdul Kader Shunsuke Koshio Manabu Ishikawa Saichiro Yokoyama Mahbuba Bulbul Yuki Honda Roger Edward Mamauag Asda Laining 《Fisheries Science》2011,77(1):119-128
A feeding trial was conducted to evaluate the effect of fermented soybean meal and scallop by-product blend (3:2) (FP) on
the performance of juvenile red sea bream. Five isocaloric diets were prepared by replacing 0% (FP0), 15% (FP15), 30% (FP30),
45% (FP45), and 60% (FP60) fishmeal (FM) protein with FP, respectively. Triplicate groups of fish (initial mean weight 2.83 g)
were fed the test diets for 45 days in a flowthrough seawater system. The results demonstrated that growth rates of fish fed
FP0, FP15, and FP30 were similar, and significantly higher (P < 0.05) than those of FP45 and FP60. Nutrient utilization was significantly lower in FP60, with no differences found among
the other groups. Dietary heavy-metal contents were affected by inclusion of FP, impacting on whole-body heavy-metal contents.
In terms of oxidative stress, fish fed the FP30 diet were in the best condition, since this fish group showed the least oxidative-stressed
condition as well as the highest tolerance against oxidation. In conclusion, the approach of utilizing this fermented mixture
is promising and it could replace at least 30% FM protein in red sea bream diet without negative effects on performance, body
composition or health of fish. 相似文献
956.
ABSTRACT: In the present study, the role of carbonic anhydrase (CA) and Na/K-ATPase in the gill and epidermal tissues in the giant freshwater prawn Macrobrachium rosenbergii was examined as a function of molting stage. CA activity levels in the front and back gills were low at the intermolt stage C0 , but increased significantly at premolt stage D3 , and then decreased after molting. In the epidermal tissue, activity levels decreased gradually towards premolt to a minimum level at stage D3 , but became elevated at postmolt stages A and B. Na/K-ATPase levels in the front and back gills did not change significantly during the molt cycle. CA in the gill is possibly involved in supplying counter-ions for ion uptake, while CA in the epidermal tissue may play a role in mineralizing the exoskeleton after ecdysis. Na/K-ATPase in the gills may function in ion uptake from the ambient medium; however, since its activity was not influenced by the molt cycle, it probably does not have a major role in osmoregulation in the freshwater environment. 相似文献
957.
Seagrasses, which form critical subtidal habitats for marine organisms worldwide, are fragmented via natural processes but are increasingly being fragmented and degraded by boating, fishing, and coastal development. We constructed an individual-based model to test how habitat fragmentation and loss influenced predator–prey interactions and cohort size for a group of settling juvenile blue crabs (Callinectes sapidus Rathbun) in seagrass landscapes. Using results from field studies suggesting that strong top-down processes influence the relationship between cannibalistic blue crab populations and seagrass landscape structure, we constructed a model in which prey (juvenile blue crabs) are eaten by mesopredators (larger blue crabs) which in turn are eaten by top-level predators (e.g., large fishes). In our model, we varied the following parameters within four increasingly fragmented seagrass landscapes to test for their relative effects on cohort size: juvenile blue crab (prey) predator avoidance response, hunting ability of mesopredators and predators, the presence of a top-level predator, and prey settlement routines. Generally, prey cohort size was maximized in the presence of top-level predators and when mesopredators and predators exhibited random searching behavior vs. directed hunting. Cohort size for stationary (tethered) prey was maximized in fragmented landscapes, which corresponds to results from field experiments, whereas mobile prey able to detect and avoid predators had higher survival in continuous landscapes. Prey settlement patterns had relatively small influences on cohort size. We conclude that the effects of seagrass fragmentation and loss on organisms such as blue crabs will depend heavily on behaviors of prey and predatory organisms and how these behaviors change with landscape structure. 相似文献
958.
Kakizaki T Hamada N Sakashita T Wada S Hara T Funayama T Hohdatsu T Natsuhori M Sano T Kobayashi Y Ito N 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(6):605-609
An analysis of ionizing radiation-induced damage in peripheral lymphocytes has been employed to predict the prognosis of radiotherapy in terms of toxicity in normal tissues. Therefore, understanding the sensitivity of lymphocytes to high linear energy transfer (LET)-charged particles would be indispensable for utilizing charged particle therapy in veterinary medicine. However, the availability of such information is very limited. This study aimed to compare the radiosensitivity of feline T lymphocytes to gamma-rays (0.2 keV/microm) and 4 different types of charged particles with LET values ranging from 2.8 to 114 keV/microm. It was observed that the relative biological effectiveness, inactivation cross-section, and isodose-induced apoptosis increased in an LET-dependent manner. On the other hand, no difference in apoptosis frequency was observed in the cells exposed to an isosurvival dose of all the radiation types tested. This is the first study that demonstrates the LET dependence of cell killing and apoptosis induction in feline T lymphocytes. Our results suggest that lymphocytes can be effectively used to predict the prognosis of charged-particle therapy in cat patients. 相似文献
959.
AGPT and HA tests were employed for rapid diagnosis of PPRV infection in sheep and goats in Sudan. Forty lymph nodes and spleen
samples from suspected cases of PPR in both sheep and goats were examined by AGPT and HA tests for detection of PPRV antigen.
Viral antigen was detected from (77.5%) of the samples tested by AGPT and (92.5%) tested by HA test. The results of both tests
revealed that HA test was more sensitive than AGPT for detection of PPRV antigen (Kappa statistics 0.4366). Another advantage
of the HA test over AGPT was that it can differentiate PPRV from RPV. Thus the HA test represents a quick, easy, simple, cheap
and reliable confirmatory test for the diagnosis of PPR and differential diagnosis of PPRV and RPV. The HA test was carried
out using chicken, goat and pig RBCs. Chicken RBCs were found to be the most sensitive for detection of PPRV antigen, followed
by goat then pig RBCs. The HA time when using chicken RBCs was 20–25 minutes, using goat RBCs was 25–30 minutes and using
pig RBCs was 40–45 minutes. The distribution of PPR infection in four different regions of Sudan was investigated. 相似文献
960.
Reena Kamal Triveni Dutt Manjunath Patel Amitava Dey Panch Kishore Bharti Poolangulam Chinnakkan Chandran 《Tropical animal health and production》2018,50(4):701-706
In tropical countries, at high temperatures, several physiological rearrangements occur in cows as they attempt to facilitate heat dissipation and/or reduce metabolic heat production. Following exposure to heat, cattle appear to acclimatize within 2–7 weeks. The failure of homeostasis at high temperatures may lead to reduced productivity or even death. The situation is even worse when humidity adds to high temperature. Livestock with elevated body temperature exhibit lower DMI and growth with less efficiency, reducing profitability for dairy farms in hot and humid climates. Shading of feed and water also offers production advantages. Although several elaborate methods for reducing heat stress in cows have been reported, simple shade materials appear to be the most cost-effective methods that are currently applicable to tropical developing countries. Different materials are being used to provide shade during warm weather. The shade material determines the microclimate—it should be light, strong, durable, weatherproof, good looking and a bad conductor of heat, and free from tendency to condense moisture inside. This review discusses various shade materials and their advantages and disadvantages in different situations. 相似文献