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D Kay

Publications and source records attributed to D Kay.

34 records · Page 2Linked to original sources
PubMed1976

Wall structure of the Neurospora hyphal apex: immunofluorescent localization of wall surface antigens.

Antisera have been raised in rabbits against three wall fractions from Neurospora crassa. Fractions were separated according to Mahadevan & Tatum (1965), i.e. fraction I, glucan-peptide-galactosamine complex; fraction III, laminarin-like glucan; and fraction IV, chitin. Distinct patterns of immunofluorescent staining were obtained using an indirect staining method. Hyphae stained with antiserum to fraction I showed maximum fluorescence in the apical and/or subapical regions: in both cases, fluorescence showed a sharp decrease with distance behing the subapical region. Hyphae stained with antiserum to fraction III showed faintly fluorescent tips with fluorescence increasing with distance from the tip. Hyphae stained with antiserum to fraction IV showed faint fluorescence, equivalent to levels of autofluorescence, except at the sites of hyphal fractures. Antisera were also raised against whole walls from 24 and 120 h cultures. Hyphae stained with antisera against whole walls which had previously been absorbed to remove antibodies to fractions I, III, and IV showed preferential staining of apices. The uncharacterized tip antigen(s) thus revealed was also demonstrated on immunodiffusion plates. This pattern of immunofluorescence was compared to the fluorescence of apices after staining with an optical brightener. Enzymic dissection procedures did not generally give reliable results with apices from 24 h cultures. Untreated apices appeared amorphous, while a drastic chemical treatment revealed randomly oriented microfibrils which were shown to be alpha-chitin. The apical hyphal walls were significantly thinner than those from more mature hyphal regions.

Antigens, Fungal↗
PubMed1976

Acremonium falciforme as a cause of mycetoma in California.

Three cases of mycetoma were studied in the San Francisco Bay area of northern California during the period from 1960 to 1973. In each case the causal agent was identified on the basis of the histological structure of the granules and by isolation of the etiological agent in pure culture. The fungus in all cases was found to be Acremonium falciforme. This is the first report of A. falciforme occurring as a disease agent in the United States.

Adult↗
PubMed1971

Sporulation in Bacillus subtilis. Effect of medium on the form of chromosome replication and on initiation to sporulation in Bacillus subtilis.

Thymine-requiring mutants of Bacillus subtilis and mutants that are temperature-sensitive for initiation of chromosome replication have been used to study the relationship between sporulation and chromosome formation. The DNA synthesis that normally occurs when cells are transferred to sporulation medium is essential for spore induction. This is shown by the fact that thymine-starved cells are unable to form spores and are unable to perform even the earlier steps of sporulation, such as septum formation or synthesis of alkaline phosphatase. The nature of the medium in which the cells are growing while the DNA is being completed is also important because it determines both the shape and the position of the daughter chromosomes. If the cells are in a rich medium, the newly synthesized chromosomes are discrete and compact bodies: the cells are primed for growth, and sporulation cannot be induced by transferring them at this stage to a spore-inducing medium. If DNA synthesis was completed with the cells in a poor medium the daughter chromosomes, by the time DNA synthesis has ceased, are spread in a single filamentous band and the cells are morphologically already in stage I of sporulation.

Alkaline Phosphatase↗
PubMed1970

Sporulation in Bacillus subtilis. Correlation of biochemical events with morphological changes in asporogenous mutants.

A comparison was made of morphological changes and successive, mainly biochemical, marker events for sporulation in 14 asporogenous mutants. The morphological and biochemical sequences are linked so that arrested development in one is accompanied by corresponding effects in the other. Thus mutants that fail to produce both protease and antibiotic do not progress beyond stage 0, formation of alkaline phosphatase appears to be associated with the transition from stage II to stage III and glucose dehydrogenase with that from stage III to stage IV. Stage II mutants may produce ;pygmy' cells or other bizarre cell-division forms. The biochemical sequence is dependent in the sense that if the occurrence of any one event is blocked that of all the succeeding events is also blocked. This has implications for biochemical models that have been proposed to explain the temporal sequence observed in spore development.

Alcohol Oxidoreductases↗
PubMed1968

Sporulation in Bacillus subtilis. Morphological changes.

1. When Bacillus subtilis was grown in a medium in which sporulation occurred well-defined morphological changes were seen in thin sections of the cells. 2. Over a period of 7.5hr. beginning 2hr. after the initiation of sporulation the following major stages were observed: axial nuclear-filament formation, spore-septum formation, release of the fore-spore within the cell, development of the cortex around the fore-spore, the laying down of the spore coat and the completion of the corrugated spore coat before release of the spore from the mother cell. 3. The appearance of refractile bodies and 2,6-dipicolinic acid and the development of heat-resistance began between 5 and 6.5hr. after initiation of sporulation. 4. The appearance of 2,6-dipicolinic acid and the onset of refractility appeared to coincide with a diminution of electron density in the spore core and cortex. 5. Heat-resistance was associated with the terminal stage, the completion of the spore coat. 6. The spore coat was composed of an inner and an outer layer, each of which consisted of three or four electron-dense laminae. 7. Serial sections through cells at an early stage of sporulation showed that the membranes of each spore septum were always continuous with the membranes of a mesosome, which was itself in close contact with the bacterial or spore nucleoid. 8. These changes were correlated with biochemical events occurring during sporulation.

Bacillus subtilis↗
PubMedDate not supplied

Infantile chlamydial conjunctivitis. A comparison of Papanicolaou, Giemsa and immunoperoxidase staining methods.

The use of conjunctival smears to diagnose infantile Chlamydia trachomatis infection increased sixteen-fold in our hospital between the years 1979 and 1984. The present study was conducted to compare Papanicolaou and Giemsa staining methods with the avidin-biotin technique of immunostaining utilizing a highly specific antichlamydial monoclonal antibody. On retrospective review of 33 patients, chlamydial infection was diagnosed in 61% of the Papanicolaou-stained and 64% of the Giemsa-stained slides. After the Papanicolaou-stained slides were destained and immunostained with the antichlamydial antibody, round particles corresponding in size to elementary and reticulate bodies were readily seen in 79% of the cases. In comparison with the immunoperoxidase method, the sensitivity and specificity of Papanicolaou staining were 73% and 86%, respectively, while the corresponding figures for Giemsa staining were 77% and 100%, respectively. The study established the applicability of the immunoperoxidase method to this clinical condition, confirmed the accuracy of diagnoses with routine stains and highlighted the increasing incidence of chlamydial conjunctivitis in our hospital population.

Chlamydia Infections↗