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排序方式: 共有463条查询结果,搜索用时 15 毫秒
81.
The objective of this study was to identify molecular markers linked to fruit-related traits in the tomato subjected to high temperatures. In total, 160 F2 plants derived from a cross between a heat-tolerant breeding line, CL5915-93D4-1-0-3 (Solanum esculentum), and a heat-sensitive wild accession, L4422 (S. pimpinellifolium), were grown in a greenhouse. Six traits including fruit number, fruit weight, brix, seed number, fruit setting, and flower number were scored. The distributions of fruit number, fruit set, flower number, and seed number were skewed towards heat susceptibility which is known to be characteristic of L4422. Polymorphic bands were generated by PCR-derived methods of RAPD, ISSR and AFLP Polymorphism, the segregation ratio, and distribution over the genome of the above 3 markers were compared. Ten linkage groups, ranging 20.6–151.6 cM in size, were constructed with 62 informative markers spanning a total of 776.3 cM. Fruit-related quantitative trait loci (QTLs) were non-randomly distributed in the tomato genome. For the 6 traits investigated, 21 QTLs were dispersed on linkage groups 2–5. The genetic effects of the various QTLs were differently exhibited, in our study we have respectively found from 10.5% to 30.2% of the variation explained by the QTL for flower number (FRN4) and brix (BX2). Thirteen QTL-mapped markers were unique to 1 trait, and 4 markers were linked to more than 1 trait. Among them, QTLs linked to the I868-470 marker had effects on fruit weight and brix, and a significant positive correlation between these 2 traits was noted (r = 0.35, P < 0.05). Thus, the I868-470 marker may have the potential for simultaneous selection of high fruit weight and brix. These markers also allowed us to align genome linkage maps across distantly related species and to reveal the co-localization between these QTLs and major genes.  相似文献   
82.
The sperm of European eel shows a high density and the time of spermatozoa motility is very short after activation with sea water. These characteristics make difficult the sperm handling and its quality assessment. Several diluents were previously described for the Japanese eel obtaining over 3 weeks’ conservation times under refrigeration, but they rendered bad results in the European species. In the present study, several diluents were developed taking as basis the P1 medium, and using different dilution ratios (1 : 50, 1 : 100) and two pH (6.5, 8.5). The effect of the addition of bovine serum albumin (BSA, 2% w/v) was also evaluated. At 24 h, undiluted samples already showed significant lower motility and viability than sperm samples diluted in the different media. The results for diluents with pH 6.5 and 8.5 were different. Spermatozoa diluted in media at pH 6.5 cannot be activated at 24 h, while samples diluted in the diluents with pH 8.5 and added with BSA did not show significant differences with respect to the fresh sperm motility until 48 h. The viability (percentage of alive cells) did not show differences until 1 week, independent of the dilution ratio. After 1 week, the motility was approximately 30% in the media containing BSA, which presented no differences for head size of the spermatozoa (perimeter and area) until 72 h and 1 week, respectively. In conclusion, the combination of one medium having similar physico‐chemical characteristics to the seminal plasma, including pH 8.5, and supplemented with BSA can be used in different dilution ratios for the sperm’s short‐term storage, preserving its motility capacity.  相似文献   
83.
Thirteen female Bedouin goats living in arid land of Algeria Sahara desert were used in this study. These goats were pregnant but they sustained an abortion because of unidentified causes. None of the goats showed any signs of general disease. Plasma concentrations of caprine pregnancy‐associated glycoproteins (cPAGs) and progesterone (P4) were determined during pregnancy using radioimmunoassay. The cPAGs concentration was undetectable (<0.8 ng/ml) throughout the first 2 weeks of gestation. From week 3 after mating, cPAGs concentration was detectable with significant individual variations (p < 0.05) reaching a maximum secretion (436.1 ng/ml). Throughout gestation, cPAGs concentration remained relatively constant but decreased few days before abortion, on an average of 9.2 ± 1.2 days (n = 11), except for two females where the concentrations decreased later (1–2 days before abortion). One or two peaks of cPAGs concentrations (in 4/13 and in 9/13 females, respectively) have been measured few weeks before abortion (77–124 days after mating), when a decline of cPAGs was detected. The P4 concentration increased after mating, and was high from the first week till the end of pregnancy. The P4 concentration (9.1 ± 0.9 ng/ml) decreased rapidly (<0.5 ng/ml) after 4 ± 0.7 days (n = 6) or 9.4 ± 1.6 days (n = 7) before abortion. A positive relationship (p < 0.01) was found between P4 and cPAGs concentrations during gestation. Results indicate that cPAGs and P4 measurements can be used for monitoring gestation and for abortion prediction.  相似文献   
84.
A 2‐year‐old Thoroughbred filly presented to the William R. Pritchard Veterinary Medical Teaching Hospital at the University of California at Davis for whole body nuclear scintigraphic evaluation after an acute onset of nonweightbearing right hindlimb lameness post race. The use of computed tomography (CT) enabled visualisation of additional pathology that was not initially appreciable using combined imaging modalities of nuclear scintigraphy and digital radiography, which ultimately altered the selected course of treatment. Computed tomography in horses with fractures of the cuboidal bones of the hock can provide valuable additional information regarding fracture configuration and radiographically occult pathology, which may help to guide clinical decisions about treatment.  相似文献   
85.
People attach multiple values to urban green spaces which play varied roles in cities. Properly designed monetary valuation surveys can ascertain their non-market value and underlying motives. This study investigates Hong Kong residents’ recreational use of urban green spaces and assesses the monetary value of these areas. A total of 495 urban residents from different neighbourhoods and socio-economic groups were interviewed. About 70% of the respondents visited urban green spaces at least weekly. Major companions during patronage were family members and then children. Exercises and clean air topped the list of visit purposes. The recreational pattern is associated with the cramped private living condition that pushes people to public open areas which are construed as extension of home space. The valuation question solicited overwhelming support, with over 80% of the respondents willing to pay to recover a possible loss of urban green spaces area by 20%. It yielded a monthly average payment of HK$77.43 (approx. 9.90 USD) per household for five years. Non-instrumental aspects played some role in the respondents’ bidding decision. The findings could assist green space planning and nature conservation, and hinted the need to consider the pluralistic community views and expectations in relevant public policies.  相似文献   
86.
Poultry litter is widely used as a fertilizer for lowland rice in Taiwan and China. However, the organic‐arsenic compound roxarsone (additive of poultry feed) in poultry litter can be absorbed by the plants and the resulting arsenic (As) contamination may pose a serious threat to human health. This study used various amounts of poultry litter contaminated with roxarsone in pot experiments to evaluate the effect of roxarsone on rice agronomic parameters and the bioaccumulation of total and inorganic As in rice‐plant tissues. Rice‐grain yield decreased significantly with increasing As content of the soil, and the critical threshold that killed rice was 200 mg roxarsone (kg soil)–1. The As concentrations in root, straw, leaf, husk, and grain increased with increasing soil As (p < 1%). At 100 mg roxarsone per kg of soil, the As concentration in the rice grain exceeded the statutory permissible limit of 1.0 mg As (kg dry weight)–1 and at 25 mg roxarsone (kg soil)–1, the inorganic As concentrations in grains exceeded the statutory limit of 0.15 mg of inorganic As kg–1 in China. For all treatments, the As concentrations in various plant tissues at maturity follow the order: root > stem > leaf > husk > grain. Arsenite was the predominant species in root, straw, and grain, while arsenate was the predominant species in leaf and husk. No significant difference existed between the amounts of arsenite and arsenate when various amounts of poultry litter were applied. This result illustrates that large amounts of added roxarsone are not only toxic to rice but also accumulate in grains in the inorganic As forms, potentially posing a threat to human health via the food chain.  相似文献   
87.
The red palm weevil (RPW), Rhynchophorus ferrugineus Olivier (Coleoptera, Curculionidae), is one of the most severe pests of ornamental palm species in urban areas of Mediterranean countries. Aiming to discover inhibitory semiochemicals for RPW population management in urban environments, we conducted electroantennographic (EAG) screenings of 17 commercially available synthetic compounds, representing three groups of plant volatiles (isoprenoids, phenyl propanoid derivatives and fatty acid derivatives) known for their repellent effects toward insects. These tests were followed by trap-based screenings of EAG-active menthone, α-pinene and methyl salicylate, singly and in combination, under urban conditions. In EAG bioassays, RPW antennae of both sexes showed positive dose-dependent responses to 13 of the 17 synthetic chemicals with significant differences among them. In field trapping experiments, conducted in the city of Palermo, Italy, from weeks 31 to 38 in 2010 and 2011, α-pinene, tested singly or in combination with methyl salicylate (2010) or menthone (2011), reduced trap catches by about 30% to 40%. Methyl salicylate and menthone alone were inactive. In conclusion, RPW is significantly affected by α-pinene. This isoprenoid is a promising disruptant for semiochemical-based management of this pest. In addition, identification of a large number of EAG-active chemicals could serve as a database for future design of active repellents or attractants of RPW adults.  相似文献   
88.
Phosphorus (P) is the least mobile nutrient in the soil as compared to other macronutrients and therefore frequently limits crop growth. During germination and early growth, seed‐phytate hydrolysis and seed‐P remobilization is the major P source for developing seedlings. The objective of this paper was to investigate whether seed‐P hydrolysis and remobilization of nonphytate P are sufficient for seedling P nutrition during early growth stages of maize. A large part of initial maize endogenous seed P reserves are mainly in the form of phytate. Till 70 cumulated degree days after sowing, nearly all the phytate (98%) was hydrolyzed and caused an increase in nonphytate P in seeds. Phytate hydrolysis and remobilization of nonphytate P was the main source of P supply for the newly growing seedlings and was not a limiting step for seedling P nutrition during the first four weeks of early growth.  相似文献   
89.
The insulin‐like growth factor‐I (IGF‐I) is a key regulator of reproductive functions. IGF‐I actions are primarily mediated by IGF‐IR. The main objective of this research was to evaluate the presence of IGF‐I and IGF‐I Receptor (IGF‐IR) in stallion testicular tissue. The hypotheses of this study were (i) IGF‐I and IGF‐IR are present in stallion testicular cells including Leydig, Sertoli, and developing germ cells, and (ii) the immunolabelling of IGF‐I and IGF‐IR varies with age. Testicular tissues from groups of 4 stallions in different developmental ages were used. Rabbit anti‐human polyclonal antibodies against IGF‐I and IGF‐IR were used as primary antibodies for immunohistochemistry and Western blot. At the pre‐pubertal and pubertal stages, IGF‐I immunolabelling was present in spermatogonia and Leydig cells. At post‐pubertal, adult and aged stages, immunolabelling of IGF‐I was observed in spermatogenic cells (spermatogonia, spermatocyte, spermatid, and spermatozoa) and Leydig cells. Immunolabelling of IGF‐IR was observed in spermatogonia and Leydig cells at the pre‐pubertal stage. The immunolabelling becomes stronger as the age of animals advance through the post‐pubertal stage. Strong immunolabelling of IGF‐IR was observed in spermatogonia and Leydig cells at post‐puberty, adult and aged stallions; and faint labelling was seen in spermatocytes at these ages. Immunolabelling of IGF‐I and IGF‐IR was not observed in Sertoli cells. In conclusion, IGF‐I is localized in equine spermatogenic and Leydig cells, and IGF‐IR is present in spermatogonia, spermatocytes and Leydig cells, suggesting that the IGF‐I may be involved in equine spermatogenesis and Leydig cell function as a paracrine/autocrine factor.  相似文献   
90.
Objective: To evaluate the clinical outcome of minimally invasive plate osteosynthesis (MIPO) for nonarticular tibial fractures stabilized using bone plates with or without an intramedullary rod (IMR). Study Design: Prospective study. Animals: Dogs (n=28) and 8 cats. Methods: After closed reduction, fracture fixation was achieved using an epiperiosteal plate inserted percutaneously through epiphyseal small incisions. In some fractures, an IMR was inserted via medial parapatellar arthrotomy. Radiographs were recommended every 3 weeks until clinical union. Postoperative tibial length and alignment were compared with contralateral measurements (P<.05). Time to clinical union and complications were recorded. Results: An IMR was used in 30.5% of the cases. Repaired tibiae were 1% shorter than contralateral tibiae (P<.05). Frontal and sagittal alignment were similar between repaired and contralateral tibiae (P>.05). Six dogs were lost for follow‐up; owners indicated normal function. In 30 cases for which bone healing was documented, mean±SD healing time was 45±20.8 days; however, when considering the 23 cases, which completed preestablished scheduled follow‐ups, healing time was 36±11.6 days. Minor complications occurred in 4 cases (11%). One major complication (3%) consisting of a plate fracture was successfully revised using MIPO with a larger plate. Conclusions: Consistent restoration of alignment was accomplished using MIPO techniques. Furthermore, MIPO appeared to yield faster healing times and lower complication rates than those reported with conventional plate osteosynthesis.  相似文献   
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