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221.
The eukaryotic genome as an RNA machine 总被引:1,自引:0,他引:1
The past few years have revealed that the genomes of all studied eukaryotes are almost entirely transcribed, generating an enormous number of non-protein-coding RNAs (ncRNAs). In parallel, it is increasingly evident that many of these RNAs have regulatory functions. Here, we highlight recent advances that illustrate the diversity of ncRNA control of genome dynamics, cell biology, and developmental programming. 相似文献
222.
Amaral Doel CM Gloster J Valarcher JF 《Veterinary journal (London, England : 1997)》2009,179(2):219-224
Foot-and-mouth disease (FMD) can be transmitted in a variety of ways, one of which is through virus exhaled into the air by infected livestock. It is clear that where there is close contact there will be a range of possible mechanisms for the transmission of disease from animal to animal, including the airborne route if simple barriers between livestock exist. In transmission of FMD over longer distances, airborne transmission represents a significant challenge to the veterinary services in that the mechanism is essentially uncontrollable if the primary source of the disease is not contained. In the event of an epidemic of FMD, such as the one experienced in the United Kingdom in 2001, it is important for disease control purposes to understand the contribution made to the overall spread of disease by aerosolised virus. This assessment is based on a combination of measurements made in the laboratory and through clinical observations in the field. To date, laboratory measurements have used a number of instruments that were not specifically designed for working with FMD virus or whose performance have not been fully compared and documented. This paper compares four samplers and describes the method by which samples are processed. Overall it is concluded that there is no optimum air sampling instrument which could be successfully employed for all situations but the work provides guidance to those wishing to make measurements in the future and establishes a baseline against which any new samplers can be compared. 相似文献
223.
R Manjarin JC Dominguez MJ Castro DJ Sprecher G Cassar RM Friendship RN Kirkwood 《Reproduction in domestic animals》2009,44(3):432-434
To ensure sufficient numbers of pregnant females, particularly at hotter times of the year, hormonal induction of gilt oestrus may be necessary. However, the gilt oestrus and ovulation responses to gonadotrophin treatment have often proven unpredictable. The objective of this study was to examine possible reasons for this unpredictability. Prepubertal gilts (approximately 150 days of age, n = 63) were assigned to one of three treatments: injection of 300 IU hCG (n = 15); pre-treatment with 100 mg FSH in polyvinylpyrrolidinone administered as 2 × 50 mg injections 24 h apart, followed by 600 IU eCG at 24 h after the second FSH injection (n = 23); or FSH pre-treatment as above followed by 300 IU hCG at 24 h after the second FSH injection (n = 25). To facilitate oestrus detection, gilts were exposed to a mature boar for 15 min daily for 7 days. Blood samples were obtained on the day of eCG or hCG injection and again 10 days later and gilt ovulation responses determined based on elevated progesterone concentrations. The oestrus responses by 7 days were 6.7%, 17.5% and 64.0% for gilts treated with hCG, FSH + eCG and FSH + hCG, respectively (p < 0.001). The oestrous gilt receiving hCG alone and one oestrous FSH + hCG gilt did not ovulate, all other oestrous gilts ovulated. A further two anoestrous FSH + eCG-treated gilts ovulated. These data suggest that FSH pre-treatment facilitated the development of ovarian follicles to the point where they became responsive to hCG, but had little effect on the response to eCG. 相似文献
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226.
Karla Paola Picoli Alice Eiko Murakami Ricardo Vianna Nunes Cristiane Regina do Amaral Duarte Cinthia Eyng Ivan Camilo Ospina-Rojas 《Tropical animal health and production》2014,46(8):1371-1381
The objective of this study was to evaluate the effect of inclusion of dehydrated cassava starch residue (DCSR) on the performance, gastrointestinal tract characteristics and carcass traits of ISA Label JA57 slow-growing broilers. A total of 510 broilers at 21 were distributed in a randomized experimental design with 5 treatments (2, 4, 6, 8, and 10 % DCSR inclusion) and a control group, 5 replicates, and 17 birds per experimental unit. The DCSR inclusion from 21 to 49 days of age negatively influenced (P?0.05) weight gain and feed intake and did not affect (P?>?0.05) feed conversion in the broilers with increasing of DCSR inclusion. From 21 to 79 days, DCSR inclusion impaired (P?0.05) weight gain, feed conversion, and poultry litter quality with increasing of DCSR inclusion. The level of blood triglycerides showed a quadratic response (P?0.05) at 79 days of age with the highest value predicted to occur at 5.45 % of DCSR inclusion. DCSR levels affected (P?0.05) the gastrointestinal organ characteristics, cecal content pH, and pigmentation of the shank, breast, and thigh meat of the birds but did not alter (P?>?0.05) the other parameters of carcass quality and yield, cuts, and percentage of abdominal fat. In conclusion, DCSR inclusion levels above 2 % compromised broiler performance. 相似文献
227.
John M. Melack Daniele Kasper João H.F. Amaral Pedro M. Barbosa Bruce R. Forsberg 《水产资源保护:海洋与淡水生态系统》2021,31(12):1041-1055
- Limnological aspects of Amazon floodplain lakes are examined in the context of aquatic conservation.
- A prerequisite to detecting and evaluating changes that could threaten the ecological health and organisms in floodplain lakes is understanding variation under present conditions. Based on one of the few studies with regular measurements over 2 years, chlorophyll, total phosphorus, dissolved oxygen, transparency, and total suspended solids in Lake Janauacá indicate that the lake is naturally quite variable with a mesotrophic to eutrophic status.
- Direct threats to ecological health of floodplain lakes include mining operations that can increase turbidity and trace metals and reduce nutritional quality of sediments. Mercury contamination and methylation leads to bioaccumulation in aquatic organisms.
- Deforestation in uplands increases nitrogen and phosphorus inputs to floodplain lakes and can alter trophic status. Deforestation in floodable forests alters the habitat and food of the fish that inhabit these forests.
- Cumulative limnological responses as catchments are altered by urban, agricultural, and industrial developments, and as inundation is altered by changes in climate and construction of dams, have major implications for the ecology of floodplain lakes.
- To improve understanding and management of threats to the conservation of aquatic Amazon biota and ecosystems requires considerably expanded and coordinated research and community-based management that includes the spectrum of floodplain lakes throughout the basin.
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229.
Abstract A Short Communication was published in the October 2002 issue of the New Zealand Veterinary Journal entitled “An investigation of the safety of oral calcium formate in dairy cows using clinical, biochemical and histopathological parameters” (McIntyre and Weston 2002). It appeared to be comparing results directly withthose of a prior communication (Scott and Van Wijk 2000). 相似文献
230.
Castration is an ancient husbandry procedure used to produce docile cattle for draught work, to reduce unwanted breeding, and to modify carcass quality. All the physical methods used to castrate cattle have side-effects and cause pain. The plasma cortisol response to castration using Burdizzo clamps and, by inference, the acute pain experienced, is less than that caused by surgical, rubber-ring or latex-band castration. The cortisol response may be influenced by the age of the animal castrated, but this has not been well defined. Local anaesthesia virtually eliminates the cortisol response, and thus the acute pain, caused by rubber-ring or latex-band castration, but needs to be combined with a systemic analgesic such as the non-steroidal anti-inflammatory drug ketoprofen to eliminate the cortisol response to Burdizzo or surgical castration. When used alone, ketoprofen sometimes reduces the cortisol response to Burdizzo or surgical castration but may need to be accompanied by local anaesthesia to eliminate the pain-induced behaviour seen during the castration process itself. Thus, pharmacological methods are available to virtually eliminate the acute pain experienced by calves during the 12 h following castration. The use of these methods is an additional cost for farmers and may be limited by the availability of drugs for farmers to use and the scarcity of veterinarians in farm animal practice. 相似文献