无核葡萄胚发育及早期离体培养的研究:Ⅲ.培养方式对离体胚发育的影响

对5个无核葡萄品种的试验表明,不同培养方式对离体胚发育的影响是很明显的,其中4个品种胚发育率液体培养高于固体培养,‘京早晶’在液体培养中胚发育率高达73.7%,是目前国内外胚发育率最高的报道;液体培养比固体培养胚的发育程度高,发育整齐,无畸形胚,易成苗.     

Bovine respiratory syncytial virus-specific immune responses in cattle following immunization with modified-live and inactivated vaccines. Analysis of the specificity and activity of serum antibodies.

Cattle were immunized with vaccines containing modified-live or inactivated bovine respiratory syncytial virus (BRSV) and serum antibody responses were analyzed. Compared with preinculation values, at Day 14 after two biweekly immunizations with modified-live or inactivated vaccines there were significant increases in BRSV-specific titers in the sera of cattle that received both types of vaccines, as determined by a whole cell ELISA. Using a blocking ELISA and radioimmune precipitation it was determined that there was recognition of the fusion (F) protein by antibodies from cattle that received both types of BRSV antigens: however, virus neutralization assays revealed that only cattle that received modified live virus, either in monovalent or polyvalent vaccines, developed neutralizing antibodies to BRSV after two immunizations. These results indicate that inactivation of BRSV can lead to a dissociation between serological recognition of the F protein and virus neutralization in vaccinated cattle.     

Increased litter size in Rambouillet sheep: I. Estimation of genetic parameters.

The variance and covariance components needed to estimate heritabilities of and genetic correlations among litter size, ovulation rate, scrotal circumference, and BW in a flock of Rambouillet sheep were estimated using REML via an expectation-maximization type algorithm. The heritability estimates from univariate analyses were .14, .21, .25, .36, and .15 for litter size, ovulation rate, scrotal circumference, 180-d BW of females, and 180-d BW of males, respectively, and average heritability estimates from bivariate analyses were .19, .20, .20, .34, and .10 for litter size, ovulation rate, scrotal circumference, 180-d BW of females, and 180-d BW of males, respectively. The genetic correlation between litter size and ovulation rate was near unity. Body weight in ewes had a moderate genetic correlation with both litter size (.22) and ovulation rate (.20) and a low residual correlation with both litter size (.03) and ovulation rate (.09). The genetic correlation between BW in rams and scrotal circumference was 0, whereas the residual correlation was .71. The genetic correlations of scrotal circumference with litter size and ovulation rate were -.25 and +.20, respectively.     

Hypokalaemic episodic polymyopathy in cats fed a vegetarian diet

A previously undocumented hypokalaemic condition with a cyclical nature, comprising acute bouts of polymyopathy followed by spontaneous recoveries, is described in the cat. Cats being fed a high protein vegetarian diet developed recurrent episodes of polymyopathy, characterised by ventroflexion of the head and neck, stiff forelimb gait, lateral head-resting and generalised muscle weakness. Plasma potassium concentrations (mean +/- standard deviation) were reduced from 3.28 +/- 0.33 mmol/l at the beginning of the experiment to 2.45 +/- 0.24 mmol/l during bouts of myopathy. This hypokalaemia was associated with increased creatine kinase activities indicative of muscle damage, and decreased urinary potassium concentrations, and was caused by insufficient dietary potassium. Cats that received the same diet supplemented with potassium did not develop hypokalaemic polymyopathy. Spontaneous recoveries of affected cats were not associated consistently with increases in plasma potassium concentrations. Plasma taurine concentrations decreased and glutamic acid increased markedly in all cats fed the experimental diet. There was no evidence of thiamin deficiency associated with the high glutamic acid intake. Veterinarians should be aware that hypokalaemic cats, and in particular those on potassium-deficient diets, may show cyclical disease with episodes of polymyopathy recurring after periods of spontaneous clinical recovery. This condition in cats may be a useful animal model for familial hypokalaemic periodic paralysis in humans.     

A context for recruitment correlations: why marine fisheries biologists should still look for them

In many cases when ecologists want to investigate a process, they often look for the best system on which to conduct the research, "best" meaning that the possibility of discovering mechanisms is optimized or made easier in some way. In fisheries we do it backwards. The species and system are given to us by economics, and we then fly in the face of the difficult circumstances to find mechanisms that are elusive anyway. These difficult circumstances constitute in some sense the first set of statistical problems. Using examples from the Northeast Pacific, I review the characteristics of cohort time series that make some species more tractable; propose a conscious process of conceptualization to assist in the formulation of clear, germane hypotheses; highlight the contrast between modeling in the sense of statistical fitting versus simulation models of processes; explore how the first round of models integrates with the second round of planning for new data collection at sea and in the lab; and, finally, propose how to judge success in terms of an operational approach.     

福建黄兔繁殖性状相关研究

本文对３１０只母兔的繁殖性状进行了测定分析，结果表明；妊娠期与产仔数、产活仔数及活仔窝重呈负相关，相关系数分别为－０．４２６＊、－０．３５０＊和－０．５１５头４胎内母兔，胎次对产仔性能无影响，对母兔泌乳性能有一定影响。同样条件下胎次增加。泌乳性能提高，第３胎较第２胎有显著提高。     

Use of netting and whitewash spray to protect papaya plants against Nivun Haamir (NH)-dieback disease

A disease causing the decline of papaya (Carica papaya) plants was noticed in the Jordan Valley in 1982. The disease caused severe yellowing of the upper leaves and dieback of the apex. The disease was not transmissible mechanically and continued efforts to associate viruses and viroids have so far been unsuccessful. Epidemiological observations suggested that the disease is airborne and probably caused by a mollicute. In order to test this hypothesis, plots were covered by an insect-proof net and with white nets providing 15, 30 and 50% shade. The 30%, 50% and insect-proof nettings provided complete protection, and the 15% netting reduced disease incidence to <2%, compared with>37% in the uncovered control plot. Spraying plants at weekly intervals with a commercial whitewash solution was also found to be effective in reducing disease incidence. The advantages of using a range of netting field treatments as a simple means for obtaining information on the epidemiological nature of a new disease are described.     

Large granular lymphoma in an FIV-positive and FeLV-negative cat

The clinical course of a feline leukaemia virus (FeLV)-negative and feline immunodeficiency virus (FIV)-positive cat affected with a large granular lymphocyte lymphoma is presented. Cyto-logical examination showed neoplastic cells in the pleural effusion and in two abdominal masses. Bone marrow and peripheral blood were moderately involved and chemotherapy was used to control the tumour. Cytochemistry, immunohis-tochemistry and ultrastructural studies were applied to define the cellular lineage; cytochemistry suggested a T-cell lineage.     

A recombinant-based feline immunodeficiency virus antibody enzyme-linked immunosorbent assay.

We have developed an antibody detection enzyme-linked immunosorbent assay (ELISA) for the identification of animals infected by feline immunodeficiency virus (FIV). The ELISA solid-phase antigen consists of recombinant FIV gag proteins expressed in bacteria. The proteins are purified from bacterial lysates as insoluble inclusion bodies. In the case of bacterially expressed p24gag, it is shown that all of the linear, sequential epitopes presented by viral p24 during infection are retained. Purified preparations can be substituted for solid-phase whole virus in the IDEXX PetChektm immunoassay. The antibody ELISA duplicates the sensitivity and specificity of the whole virus based PetChek plate assay.     

Immunocytochemical Study of the Ultimobranchial Tubule in Wistar Rats

A systematic immunohistochemical study of the ultimobranchial tubule (UBT) has been carried out in 45 Wistar rats of different ages (0, 5, 10, 15, 20, 25, 30, 60 and 120 days). The existence of calcitonin immunoreactive cells in the UBT wall has been demonstrated in a 5-days old rat. In addition, immunohistochemical studies for thyroglobulin revealed positive staining in follicular cells connected to the UBT and, occasionally, in isolated cells lying within solid clusters from the UBT. These last results together with the continued and repeated existence of numerous mitosis and PAS (+) microfollicles, apparently rising from the UBT, support the hypothesis that the ultimobranchial body (UBB) may contribute partially to the formation of a part of the follicular component.