Shedding of the upper parts of grapevine shoots

Shedding of the upper parts of unlignified grapevine (Vitis vinifera L.) canes is frequent during autumn. Stress conditions during the growing-season lead to similar shedding of shoot tips. The separation process occurs above a node in the boundary area between the distal part of the diaphragm and the pith.Ethephon (2-chloroethyl-phosphonic acid) sprays, at 750 or 1500 mg l^?1, induced separation of the shoot tips of ‘Perlette’ and ‘Queen of the Vineyards’. Ethylene (C₂H₄) 200 vpm and ethephon at 10, 100 and 1000 mg l^?1 enhanced separation in shoot explants, whereas 2,4,5-TP (2,4,5-trichlorophenoxy-propionic acid) at concentrations above 1 mg l^?1 arrested it.This phenomenon may be regarded as a shoot abscission process which may represent adaptation of self-pruning of the grapevine.     

Afferent and efferent connections of the nucleus rotundus demonstrated by WGA-HRP in the chick

Organization of the fibre connections in the chick nucleus rotundus (Rt) was investigated by an axonal tracing method using wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). After an injection of WGA-HRP into the Rt, labelled neurones were observed in the striatum griseum centrale (SGC) in both sides of the tectum (TO) and in the ipsilateral nucleus subpretectalis/nucleus interstito-pretecto-subpretectalis (SP/IPS). Labelled fibres and terminals were also found in the ipsilateral ectostriatum (Ect). These fibre connections were topographically organized rostrocaudally. In the TO-Rt projection, the rostral and the dorsocaudal parts of the Rt received afferents from the superficial part of the SGC, the middle part of the Rt received afferents from the intermediate part of the SGC, and the ventrocaudal part of the Rt received mainly fibres from the deep part of the SGC. These topographic projections were accompanied by a considerable number of diffuse projections to the thalamic regions surrounding the Rt. In addition, the rostral and middle caudal parts of the Rt received afferents from the lateral and medial parts of the SP/IPS, respectively, and respective parts of the Rt sent efferents to the lateral and medial parts of the Ect.     

Linkage analysis using direct and indirect counting and relative efficiencies for codominant and dominant loci

A method based on direct and indirect counting is developed for rapid and accurate linkage analysis for codominant and dominant loci. Methods for estimating gender-specific recombination frequencies are available for cases where at least one of the two loci is multiallelic and for biallelic loci with mixed parental linkage phases where at least one locus is codominant. Most of the estimates of gender-average and gender-specific recombination frequencies required iterative solutions. The new method makes use of the full data set, yields exact estimates of the recombination frequencies when the observed and expected genotypic frequencies are equal, and are computationally efficient. Relative efficiency of various data types is affected by the inheritance mode and by parental linkage phases of biallelic loci, but unaffected by the locus polymorphism when using the full data set for linkage analysis. The ability to determine parental linkage phases is affected by the locus polymorphism as well as inheritance mode. Intercross (or F-2 design) is more efficient for mapping codominant loci, whereas backcross is more efficient if dominance is involved. Mixed parental linkage phases of biallelic loci are less efficient than coupling or repulsion linkage phases. Ignoring noninformative offspring results in biased estimates of recombination frequency for biallelic loci only and reduced LOD scores for all cases.     

Intracranial lymphomas in simian retrovirus-positive Macaca fascicularis

Two young adult Macaca fascicularis each had unilateral mydriasis and ptosis. Both animals were euthanatized, monkey No. I for progressive neurologic signs and monkey No. 2 because of a positive intradermal tuberculin test. At necropsy, each animal had a single intracranial mass on the ventral surface of the midbrain, surrounding the oculomotor nerve. Histologically, both masses were immunoblastic lymphomas. Immunohistochemical staining revealed the neoplasms to be of B-cell origin. Simian retrovirus (SRV) was isolated from both monkeys, but simian immunodeficiency virus was not found. Both animals lacked antibody to SRV. Both animals had antibodies to Epstein-Barr-like virus (EBV), but EBV antigens were not found by immunohistochemistry. Polymerase chain reaction analysis for integrated EBV DNA was unproductive. One of the animals (monkey No. 2) had a pulmonary infection with Mycobacterium avium, suggesting that immunosuppression was present. These cases represent a unique and previously undescribed type of solitary lymphoma in SRV-infected macaques.     

Surface alterations in the bovine pelvic peritoneum following rectal examination of reproductive organs: a scanning electron microscopy study

The aim of the present study was to evaluate possible injury provoked by an intensive reproductive programme based on rectal palpation in the cow. Alterations to the mesothelial surface of the peritoneum and to the oviductal mucosa were explored by scanning electron microscopy (SEM). Nine multiparous Friesian cows were selected from each of two commercial dairy herds. Cows in herd 1 were maintained on a weekly reproductive health programme, while those in herd 2 were not subjected to gynaecological exploration. Surface features of the mesothelial cells of the reproductive tract and adjacent ligaments, and the oviductal mucosa were explored by SEM observation of tissue specimens from each animal. Six cows in the intensive reproductive programme showed microscopic alterations of the peritoneal surface. Strands were observed in the oviducts and adjacent ligaments in five of these cows. These strands, composed of filaments covered with mesothelial cells, were probably adhesions. Cells with abundant vacuoles on their surface were detected in the mesothelium corresponding to three animals, two of which also showed microscopic strands. No peritoneal surface alterations were observed in the cows from herd 2. No oviductal mucosal modifications were detected in either group. These findings suggest that intensive reproductive programmes based on rectal palpation may increase the risk of peritoneal surface alterations in the cow, but effects on reproductive physiology are unlikely.     

GM1 gangliosidosis in shiba dogs

A six-month-old shiba dog with a one-month history of progressive motor dysfunction showed clinical signs of a cerebellar disorder, including ataxia, dysmetria and intention tremor of the head. Histopathological and ultrastructural studies revealed distended neurons packed with membranous cytoplasmic bodies throughout the central nervous system. The activities of lysosomal acid beta-galactosidase in its leucocytes and liver were less than 2 per cent of the control levels, and the compound accumulated in the brain was identified as GM1 ganglioside. A sibling which died immediately after birth was shown to have a beta-galactosidase deficiency in the brain and visceral organs. A family study revealed that the sire and dam of the probands were heterozygotes with approximately half of the normal level of beta-galactosidase activity, suggesting an autosomal recessive pattern of inheritance.     

Congenital thymic aplasia in a Holstein-Israeli female calf

An unusual case of congenital thymic aplasia in a Holstein-Israeli female calf is described. The most prominent clinical findings were diarrhoea and weakness. At necropsy, the only significant pathological finding was the marked decrease in thymus size. Histologically, this organ was composed of loose connective tissue in which a few lymphocytes were scattered randomly.     

Evaluation of semen from individual male domestic fowl by assessment of sperm perivitelline interaction in vitro and in vivo

1. Spermatozoa in semen samples from 8 individual male domestic fowls were shown to have a differential and characteristic ability to hydrolyse holes in the inner perivitelline layer from laid eggs in an in vitro assay. 2. The number of holes produced by samples of spermatozoa per unit area of inner perivitelline layer in vitro was linearly correlated with sperm ATP content ( r = 0.85) and motility (r=0.76). 3. The number of holes formed in the inner perivitelline layer in vitro was also linearly correlated with the numbers of holes formed in the inner perivitelline layer of eggs fertilised in vivo , in inseminated hens (r=0.90); and was correlated logarithmically with the proportion of fertile eggs laid by these hens.     

Investigation of the effects of bark fiber as core material and its resin content on three-layer MDF performance by response surface methodology

The effects of using 100% black spruce (Picea mariana) bark fibers as core layer material accounting for up to 70% of the board and its resin content (between 6 and 10%) on the properties of three-layer medium-density fiberboard (MDF) were investigated using a full factorial experimental design with two independent variables and three levels. Five response variables, namely internal bond strength, modulus of rupture, modulus of elasticity, thickness swelling and water absorption were statistically analyzed using a response surface methodology and two-way analysis of variance. The effects of the proportion of core layer (bark fibers) and its resin content on panel properties were significant. All properties studied were positively affected by increasing core layer resin content. The effects of the proportion of core layer (bark fibers) on mechanical properties and water absorption were negative, but positive on thickness swelling. Simultaneous optimization of panel properties indicated that at a density of 850 kg/m³, a three-layer MDF with a core layer resin content of 6.5%, a face resin content of 12 and 60% of core layer proportion (spruce bark fibers) would satisfy the minimum requirements of ANSI standard for 130-grade MDF. Overall, black spruce bark, a major residue source in the Eastern Canada, should be considered as a supplemental furnish for the core layer materials of a three-layer MDF.