OXIDOREDUCTIVE DEGRADATION OF SOIL MINERALS AND CLAYS D,L-3(3,4-DIHYDROXYPHENYL) ALANINE BY SOIL MINERALS AND CLAYS

The effect of the perhydrol (H₂O₂) treated soils on the decarboxylation rate of d,1-3(3,4-dihydroxyphenyl) alanine (DOPA), as examined by radiorespirometry, is highly significant and well-correlated (r=+0.913) with the clay content. Among the pure Na clays used, Wyoming bentonite had the strongest effect on the DOPA decarboxylation. The reaction was activated by phosphate buffer and completely inhibited by a dithionite treatment. Gas phases like carbon monoxide, hydrogen, or nitrogen do not inhibit the DOPA decarboxylation rate. A chromatographic study of the intermediate products formed during DOPA degradation reveals the presence of 5,6-dihydroxyindole. These results suggest that DOPA degradation by clays proceeds by a sequence of oxidoreductive reactions following the Raper (1927) scheme. The ferric oxides associated with the clay, and not the dissolved oxygen, are the electron acceptors. DOPA is oxidized to eumelanin which has an elementary percentage composition of C = 62.65; N = 11.05; H = 6.30; 0 = 20.     

The effects of apple rootstock genotypes on mineral content of scion leaves

Summary The relative effects of year to year variation and rootstock genotypes on the major content of leaves of four apple scion cultivars were studied. For nitrogen and phosphorus the main source of variation was due to years. For potassium, magnesium and calcium there were significant genetic effects. The results are discussed in relation to breeding for improved efficiency in mineral uptake in apple rootstocks. Particular reference is made to uptake of minerals associated with physiological disorders of stored apples.     

A biosystematic study of the origin of the cultivated diploid potato,Solanum x Ajanhuiri Juz. et Buk.

Summary The origin and nature of the diploid cultivated potato species S. ajanhuiri Juz. et Buk. was studied. Several lines of evidence indicate that S. ajanhuiri might be derived from natural crosses between primitive cultivars of the diploid species S. stenotomum and the wild species S. megistacrolobum. Morphological comparisons were made between S. stenotomum x S. megistacrolobum F₁ hybrids and naturally occurring S. ajanhuiri to investigate this hypothesis. Comparisons were also made between S. ajanhuiri x S. stenotomum crosses and the F₂ generation of the first-mentioned cross.Crosses between the two major groups of S. ajanhuiri cultivars, Ajawiri and Yari, showed not only genetic breakdown but also a wide range of phenotypic variation similar to those of artificial F₂ families of S. stenotomum x S. megistacrolobum. Furthermore, there was strong evidence showing that the Yari group of S. ajanhuiri could almost certainly be an F₁ S. stenotomum x S. megistacrolobum hybrid, whereas the Ajawiri group could be a backcross of an F₁ hybrid to S. stenotomum. These results added further support to the hypothesis of a hybrid origin of S. ajanhuiri, as well as indicating its putative parents. It is suggested that this hybridogenic taxon be retained at the species level under the name Solanum x ajanhuiri.     

Hereditary phosphofructokinase deficiency in wachtelhunds

Hereditary phosphofructokinase (PFK) deficiency was diagnosed in two Wachtelhund dogs and suspected in three related Wachtelhund dogs with exercise intolerance, hemolytic anemia, and pigmenturia. Severe, persistent reticulocytosis in light of only mild anemia together with hemoglobinuria after strenuous exercise suggested PFK deficiency. Low erythrocyte PFK activity together with low 2,3-diphosphoglycerate concentrations and a high hemoglobin-oxygen affinity confirmed the diagnosis. The PFK deficiency is due to a single missense mutation in the muscle-type PFK M-PFK gene in English springer and American cocker spaniels, whippets, and mixed-breed dogs; however, these PFK-deficient Wachtelhunds do not have the same PFK mutation.     

Serum bile acid concentrations in clinically normal cattle: comparison by type, age, and stage of lactation.

Serum total bile acid concentrations were determined for various types and ages of cattle. There was extreme variability among all the cattle, but the variance was twice as large (0.50 vs 0.22 in logarithmic scale) for beef cattle than for dairy cattle. There was no significant difference in serum total bile acid concentrations between beef cattle and dairy cattle in midlactation. Values for calves < 6 weeks old and for 6-month-old heifers were significantly (P = < 0.05) lower than values for lactating dairy cows. The 5th to 95th percentile range of values (mumol/L) for beef cattle was 9 to 126; for lactating dairy cattle, 15 to 88; and for 6-month-old dairy heifers, 11 to 64.     

Photosensitization problems in livestock

Photosensitization is a sunburn-like condition caused by the presence of certain photoactive compounds in the skin when it is exposed to the appropriate wavelength of light. Most photoactive compounds (phototoxic agents) that cause PS in livestock are of plant origin, others are drugs, chemicals, or endogenous porphyrins. Photosensitization is a disease caused by phototoxic xenobiotics, or by acquired or hereditary dysfunction of (1) heme synthesis or (2) PE excretion by the liver. Hepatotoxins, especially those of plant origin, most frequently are the cause of the condition. Photosensitization primarily is a disorder of sheep and cattle, but all classes of livestock are susceptible. Clinical recognition of the syndrome usually presents no difficulty because of the restriction of lesions to areas of skin unprotected from sunlight. Prognosis generally depends on the extent of hepatic injury. The most important elements of treatment are termination of exposure to the photo- or hepatotoxin, protection from light, treatment and prevention of infection and fly strike, and provision of nutritious feed.     

Transmission of bovine leukaemia virus in milk

Summary Nineteen calves born to dams free of bovine leukaemia virus (BLV) did not possess maternally derived precipitating antibody to BLV in their sera after the ingestion of colostrum. Eight of these calves remained serologically negative after being fed milk from BLV-free cows while three (27.3%) of 11 similar calves that had been fed milk from BLV-infected cows developed antibody. Forty-four of 47 calves born to BLV-infected dams acquired maternal antibody to BLV after ingesting colostrum. Two (8.7%) of the 23 calves fed milk from BLV-free cows developed antibody to BLV probably as a result of transplacental or colostrum infection whereas four (16.7%) of the 24 calves fed milk from BLV-infected cows developed antibody. It is concluded that milk transmission of BLV is responsible in part for the high rates of infection encountered in our dairy herds and that calves lacking specific maternal antibody are more susceptible to BLV infection through the ingestion of milk than are calves with maternal antibody.

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Transmission Del Virus De La Leucemia Bovina Por La Ingestion De Leche

Resumen Diezinueve bezerros nacidos de vacas libres del virus de la leucemía bovina (VLB) no poseían anticuerpos precipitantes de origen materno contra el VLB en el suero después de la ingestión de calostro. Ocho de estos bezerros permanecieron serologicamente negativos después de ser alimentados con leche de vacas libres del VLB mientras que tres (27.3 por ciento) de 11 bezerros similares que habían sido alimentados con leche de vacas infectadas con el VLB desarrollaron anticuerpos. Cuarenta y cuatro de 47 bezerros nacidos de vacas infectadas con el VLB adquirieron anticuerpos maternos contra el VLB después de ingerir calostro. Dos (8.7 por ciento) de los 23 bezerros alimentados con leche de vacas libres del VLB desarrollaron anticuerpos contra el VLB, probablemente como resultado de una infección transplacentaria o através del calostro, mientras que cuatro (16.7 por ciento) de los 24 bezerros alimentados con leche de vacas infectadas con el VLB desarrollaron anticuerpos. Se concluye que la transmisión del VLB através de la leche es responsable, en parte, por los altos índices de infección encontrados en nuestros rebaños lecheros y que bezerros sin anticuerpos específicos maternos son mas susceptibles a la infección con el VLB através de la ingestión de leche que los bezerros que poseen estos anticuerpos.

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Transmission De La Leucose Bovine Parlelait

Résumé Dix neuf veaux issus de mères indemnes de virus de la leucose bovine (VLB) ne possédaient pas d'anticorps précipitants pour le VLB dans leur sérum après ingestion de colostrum. Huit d'entre eux sont restis sérologiquement négatifs après avoir été alimentés avec du lait provenant de vaches indemnes de VLB alors que trois (27,3 p.100) des 11 veaux restants qui avaient été alimentés avec du lait provenant de vaches infectées de VLB ont produit des anticorps. Quarante quatre veaux sur quarante sept issus de mères infectées de VLB ont acquis des anticorps maternels anti VLB après ingestion de colostrum. Deux (8,7 p. 100) veaux sur vingt trois alimentés avec du lait de vaches indemnes de VLB ont produit des anticorps anti VLB probablement à la suite d'infection transplacentaire ou par le colostrum alors que quatre (16,7 p. 100) veaux sur vingt quatre recevant du lait de vaches infectées de VLB ont produit des anticorps. On conclut que la transmission du virus de la leucose bovine par le lait est en partie responsable des taux élevés d'infection rencontrés dans nos troupeaux laitiers et que les veaux manquant d'anticorps maternels spécifiques sont plus sensibles à l'infection par le VLB par ingestion de lait que ceaux ayant reçu des anticorps maternels.