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Biomedical subjects

A Zachary

Publications and source records attributed to A Zachary.

8 recordsLinked to original sources
PubMed1992

Isolation and characterization of a portal protein-DNA complex from dsDNA bacteriophage.

A portal protein-DNA complex was isolated from bacteriophage disrupted in 70% acetic acid. This treatment dissociated most of the phage structural proteins, while the portal protein ring remained attached to the highly condensed naked DNA. In the absence of a headful of DNA, the portal ring was not protected. Purification of the portal ring-DNA complex by density gradient centrifugation showed that a dsDNA fragment of about 40 bp was protected from DNase digestion by this association, suggesting it was internalized within the 140 A long, 20-40 A in diameter T4 apical channel of the ring dodecamer. A portal ring-DNA complex could be isolated from a number of phages (T4, T7, Phi29), and the end(s) of phage T7 DNA was (were) found to be preferentially associated with the ring complex.

Acetates↗
PubMed1979

Ecology and taxonomy of bacteria attaching to wood surfaces in a tropical harbor.

Water, sediment, and wooden pilings, samples of which were collected from a harbor in Puerto Rico during the course of a long-term study of biofouling of wood treated with creosote and related compounds, were found to support growth of microbial populations, the dominant taxa of which included Hyphomicrobium, Hyphomonas, Pseudomonas, Vibrio, and Bacillus. New wood exposed to the harbor water was rapidly colonized by Hyphomicrobium vulgare. Old pilings in an advanced stage of biodeterioration maintained a diverse bacterial microflora, representatives of which were also found widely distributed in the water column and sediment. Evidence for bacterial species succession was obtained, indicating that microbial interactions are important for attachment to, and subsequent colonization of, wood surfaces in the marine environment.

Bacteria↗
PubMed1978

An ecological study of bacteriophages of Vibrio natriegens.

Effects of temperature and anaerobic conditions on the replication of two bacteriophages, nt-1 and nt-6, of the estuarine bacterium Vibrio natriegens were studied. Reduction in temperature resulted in longer latent periods and reduced burst sizes for both phages. Replication under anaerobic conditions resulted in longer latent periods; however, phage nt-6 had a reduced burst size, whereas phage nt-1 had an increased burst size, resulting in a rate of phage production nearly equal to that observed under aerobic conditions. Therefore the distribution of the phages in marsh areas could be influenced by temperature and anaerobiosis.

Anaerobiosis↗
PubMed1977

Epitheliocystis disease in the striped bass Morone saxatilis from the Chesapeake Bay.

Epitheliocystis disease in the gills of the striped bass Morone saxatilis from Chesapeake Bay was studied using light and electron microscopy. The epitheliocystis infection appeared synchronous in that all capsules on a single host were at the same stage of development. The disease appeared to begin in a single cell on the gill lamella, which gradually enlarged to form a large cyst, encapsulated by a thick cellular capsule of epithelial origin. The epitheliocystis inclusion was filled with cells of the general morphology and size of rickettsiae; however, the infection was atypical for rickettsiae in that the cells had a dense central nucleoid region and they developed within an inclusion separated from the host cytoplasm.

Animals↗
PubMed1976

Physiology and ecology of bacteriophages of the marine bacterium Beneckea natriegens: salinity.

The effects of variation in ionic levels on the stability and replication of two bacteriophages (nt-1 and nt-6) host specific for the marine bacterium Beneckea natriegens were examined. Monovalent cations influenced the adsorption of the nt-1 but not the nt-6 phage; however, one-step growth studies showed that NaCl was required for replication of both phage. The NaCl optimum for nt-1 production was 0.25 M NaCl, the same as the growth optimum for B. natriegens. However, the optimum for nt-6 production was 0.16 M NaCl. These NaCl optima for host and phage are at estuarine rather than oceanic levels. The nt-1 phage was better suited to replicate at NaCl levels typical of higher salinity areas (18-35%) and the nt-6 phage was better suited to replicate at lower salinities (5-18%). The nt phage were more resistant to low NaCl levels than their host bacterium and appeared limited to marine waters by the lower survival salinity of B. natriegens coupled with phage inactivation processes occurring in natural estuarine waters.

Adsorption↗