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Biomedical subjects

A Wiseman

Publications and source records attributed to A Wiseman.

At least 127 records · Page 7Linked to original sources

The mitochondrial genome of Chlamydomonas. II. Genetic analysis of non-mendelian obligate photautotrophic mutants.

Among a collection of obligate photoautotrophic (dark-dier, dk) mutants isolated in Chlamydomonas reinhardtii, two have been found which are inherited in crosses to wild type in a non-Mendelian, biparental and apparently random fashion. F1 progeny include not only cells which show the dk and wildtype parental phenotypes but also many which possess intermediate phenotypes between wild type and dk. When F1 progeny with dk, intermediate or wild-type phenotype were backcrossed to wild type, the dk phenotype continued to be inherited in a biparental and random fashion. Upon selection, neither mutant formed stable clones producing only dk progeny, suggesting that the two mutants segregate dk and wild-type progeny somatically and that the homozygous dk condition may be lethal. The biparental transmission of these two non-Mendelian dk mutations resembles the transmission of acriflavin-induced minute mutations of Chlamydomonas and is distinct from the uniparentally inherited chloroplast mutations of this alga. Both the dk and minute mutations may alter mitochondrial DNA and thereby alter mitochondrial functions.

Animals↗

Nuclear mutations affecting mitochondrial structure and function in Chlamydomonas.

Wild type cells of the green alga Chlamydomonas reinhardtii can grow in the in the dark by taking up and respiring exogenously supplied acetate. Obligate photoautotrophic (dark dier, dk) mutants of this alga have been selected which grow at near wild type rates in the light, but rapidly die when transferred to darkness because of defects in mitochondrial structure and function. In crosses of the dk mutants to wild type, the majority of the mutants are inherited in a mendelian fashion, although two have been isolated which are inherited in a clearly nonmendelian fashion. Nine mendelian dk mutants have been analyzed in detail, and belong to eight different complementation groups representing eight gene loci. These mutants have been tentatively grouped into three classes on the basis of the pleiotropic nature of their phenotypic defects. Mutants in Class I have gross alterations in the ultrastructure of their mitochondrial inner membranes together with deficiencies in cytochrome oxidase and antimycin/rotenone-sensitive NADH-cytochrome c reductase activities. Mutants in Class II have a variety of less severe alterations in mitochondrial ultrastructure and deficiencies in cytochrome oxidase activity. Mutants in Class III have normal or near normal mitochondrial ultrastructure and reduced cytochrome oxidase activity. Eight of the nine mutants show corresponding reductions in cyanide-sensitive respiration.

Alleles↗

An outbreak of acute pneumonia in young, single-suckled calves.

An outbreak of acute severe pneumonia which affected six to 14-week-old single-suckled calves, resulted in 45/77 requiring treatment. The examination of paired sera from all affected calves revealed that neither an adenovirus, non infectious bovine rhinotracheitis virus nor parainfluenza 3 virus was involved. The acute exudative interstitial pneumonia found at post mortem was typical of pneumonic pasteurellosis.

Animals↗

Pulmonary arterial thrombo-embolism and pulmonary arterial mycotic aneurysms in cattle with vena caval thrombosis: a condition resembling the Hughes-Stovin syndrome.

Sixteen cattle affected by thrombosis of the posterior vena cava were examined post mortem and the various lesions are described. The thrombus was in the hepatic portion in 12 animals and in the intrathoracic part in four. Thrombi had formed as a result of phlebitis in 13 cases in which hepatic or post-diaphragamatic abscesses were present but the aetiology of the other three was not discovered. Embolism from the vena cava thrombus resulted in pulmonary lesions in every case: these included pulmonary arterial thrombo-embolism, pulmonary arteritis, pulmonary endarteritis, chronic suppurative pneumonia and the formation of multiple pulmonary abscesses. The pulmonary arterial lesions had given rise to mycotic aneurysms of that vessel and rupture of these was followed by massive haemoptysis or intrapulmonaary haemorrhage. Pulmonary arterial aneurysms are not common in man and are very rare in animals, except in association with vena cava thrombosis of cattle. However, the "Hughes-Stovin" syndrome of man has some features in common with the condition described in cattle and these are discussed. The different sequelae of posterior vena cava thrombosis and infective endocarditis of the right heart in cattle are also considered.

Aneurysm, Infected↗

Acute respiratory distress in cattle.

The term "fog fever" was originally used identify a disease of adult cattle grazing lush pastures in the autumn. Unfortunately, the name has subsequently been applied to other respiratory disorders which occurred under different epidemiological circumstances, so that the name "fog fever" has lost much of its original specificity and become almost synonymous with "acute respiratory distress". The pulmonary lesions in 151 cattle, of all ages, with acute respiratory distress are described in this report. While most of the animals were referred as examples of "fog fever", in only 43 of the 151 cases were the clinical signs, epidemiology and post mortem findings consistent with that disease. Twelve other pulmonary disturbances were encountered in the other animals and the pathology of these conditions has bee described.

Animals↗