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1.
Cumulus-oocyte complexes from hormone-stimulated 3-4-week-old (n=43) and 6-7-week-old (n=12) prepubertal lambs were matured in vitro and incubated with unsorted, or X- or Y-spermatozoa separated with a high-speed cell sorter (SX MoFlo)frozen-thawed. Presumptive zygotes were then cultured to the blastocyst stage, and transferred to recipients fresh or after cryopreservation (frozen). Oocyte cleavage was higher (p <0.05) with unsorted (515/926, 55.6%) than X- or Y-spermatozoa (261/672, 38.8% and 229/651, 35.2%, respectively) and blastocyst formation (% zygotes) by Day 9 of in vitro culture was lower (p <0.05) for X- (102/261, 39.1%) than unsorted spermatozoa (249/515, 48.3%), but did not differ between Y-spermatozoa (103/229, 45.0%) and unsorted spermatozoa, or between X- and Y-spermatozoa (p >0.05). For fresh embryos, survival to term was 50.0% (3/6) for unsorted, 0.0% (0/6) for X- and 16.7% (1/6) for Y-spermatozoa-derived embryos (p >0.05), and for frozen embryos was 4.0% (2/50) for unsorted, 9.1% (2/22) for X- and 2.9% (1/34) Y-spermatozoa-derived embryos (p >0.05). Of the two lambs born from X-spermatozoa-derived embryos, one was female (50%), and from the two Y-spermatozoa-derived lambs, both were male (100%), demonstrating that lambs can be produced after the transfer of fresh and cryopreserved IVP embryos derived from prepubertal lamb oocytes and frozen-thawed sex-sorted sperm.  相似文献   
2.
SUMMARY Repeated scouring and soiling of the breech region with faeces rendered mulesed, Merino sheep susceptible to breech strike. Anthelmintic treatment of ewes before and after lambing and of lambs 6 to 8 weeks old reduced intestinal trichostrongylosis, scouring and consequent breech strike. Wether lambs tended to be more susceptible than ewe lambs and sheep grazing long pastures were struck more frequently than those on short pastures.  相似文献   
3.
The aqueous extract of the Cocculus hirsutus aerial parts (100 and 200 mg/kg, p.o.) showed significant diuretic activity and laxative effect in rats. The acute toxicity, orally evaluated in mice, was found to be higher than 3000 mg/kg.  相似文献   
4.
The immune response to mixed whole cell antigens of Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas fluorescens, the common Gram negative bacterial pathogens associated with diseases of Indian major carps were evaluated for their efficacy in triggering antibody responses in rohu, Labeo rohita (Ham.). The rohu yearlings were either immunized with antigens from single bacterial strain, A. hydrophila, E. tarda and P. fluorescens or a combination of all three. An antibody response was detected at 1st week post immunization that rose significantly (p<0.05) at 4th week post immunization in all the immunized groups. The antibody level started declining after 8th week but persisted up to 10th week post immunization in all the immunized groups. Similarly, no significant difference (p>0.05) in the antibody level was found between groups immunized with single and mixed bacterial antigens. Moreover, the use of mixed bacterial antigens did not jeopardize the specific immune response to the vaccine components. Upon challenge with single pathogen, a high relative percent survival was recorded in the group immunized with mixed bacterial antigens and was comparable to those fish immunized with the single bacteria.  相似文献   
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6.
Side-chain ferroelectric liquid crystalline polymers are currently used in a number of applications, including displays and electrical sensors. Comparisons with existing technologies and materials indicate that relative to ceramics, such polymers have lower figures of merit but offer greater durability in sensor applications.  相似文献   
7.
This article examines the efforts by the Northwest Treeplanters and Farmworkers United union to organize Mexican migrant farmworkers in the Willamette Valley. It focuses on the union's 1995 organizing campaign of strawberry picker?s, the largest campaign in the history of Pacific Northwest agriculture. To provide context for the union's efforts, the article develops the historical role and changing nature of Oregon agriculture, sketches the politics of agriculture in the state, and describes the industry's labor system. The article concludes that significant gains for strawberry pickers were made during the 1995 campaign; the long-term consolidation of those gains remains to be demonstrated.  相似文献   
8.
DARPP-32, a dopamine- and adenosine 3',5'-monophosphate (cAMP)-regulated phosphoprotein (32 kilodaltons in size), is an obligate intermediate in progesterone (P)-facilitated sexual receptivity in female rats and mice. The facilitative effect of P on sexual receptivity in female rats was blocked by antisense oligonucleotides to DARPP-32. Homozygous mice carrying a null mutation for the DARPP-32 gene exhibited minimal levels of P-facilitated sexual receptivity when compared to their wild-type littermates. P significantly increased hypothalamic cAMP levels and cAMP-dependent protein kinase activity. These increases were not inhibited by a D1 subclass dopamine receptor antagonist. P also enhanced phosphorylation of DARPP-32 on threonine 34 in the hypothalamus of mice. DARPP-32 activation is thus an obligatory step in progestin receptor regulation of sexual receptivity in rats and mice.  相似文献   
9.
Sera from hosts infected with a variety of nematodes were examined for the presence of antibodies against nematode acetylcholinesterase (AChE). Antibodies were detected in the serum from hosts infected with Oesophagostomum spp., Ostertagia spp. and Trichostrongylus spp., but not in serum from hosts infected with Cooperia pectinata or Haemonchus spp., Toxocara spp. or Trichuris vulpis. In those infections in which anti-AChE antibodies were found, some individual animals failed to produce detectable antibodies. The enzyme appeared to possess antigenic specificity at the genus but not the species level.  相似文献   
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