Biomedical subjects

J C Crowley

Publications and source records attributed to J C Crowley.

25 records · Page 2Linked to original sources

PubMed1987

Molecular cloning of chromosome I DNA from Saccharomyces cerevisiae: isolation and analysis of the CEN1-ADE1-CDC15 region.

To continue the systematic examination of the physical and genetic organization of an entire Saccharomyces cerevisiae chromosome, the DNA from the CEN1-ADE1-CDC15 region from chromosome I was isolated and characterized. Starting with the previously cloned ADE1 gene (J. C. Crowley and D. B. Kaback, J. Bacteriol. 159:413-417, 1984), a series of recombinant lambda bacteriophages containing 82 kilobases of contiguous DNA from chromosome I were obtained by overlap hybridization. The cloned sequences were mapped with restriction endonucleases and oriented with respect to the genetic map by determining the physical positions of the CDC15 gene and the centromeric DNA (CEN1). The CDC15 gene was located by isolating plasmids from a YCp50 S. cerevisiae genomic library that complemented the cdc15-1 mutation. S. cerevisiae sequences from these plasmids were found to be represented among those already obtained by overlap hybridization. The cdc15-1-complementing plasmids all shared only one intact transcribed region that was shown to contain the bona fide CDC15 gene by in vitro gene disruption and one-step replacement to delete the chromosomal copy of this gene. This deletion produced a recessive lethal phenotype that was also recessive to cdc15-1. CEN1 was located by finding a sequence from the appropriate part of the cloned region that stabilized the inheritance of autonomously replicating S. cerevisiae plasmid vectors. Finally, RNA blot hybridization and electron microscopy of R-loop-containing DNA were used to map transcribed regions in the 23 kilobases of DNA that went from CEN1 to CDC15. In addition to the transcribed regions corresponding to the ADE1 and ADC15 genes, this DNA contained five regions that gave rise to polyadenylated RNA, at least two regions complementary to 4S RNA species, and a Ty1 transposable element. Notably, a higher than average proportion of the DNA examined was transcribed into RNA.

Centromere↗

PubMed1986

Transcriptional map of the measles virus genome.

We have constructed a recombinant DNA library of the measles virus genome and identified gene-specific clones containing sequences coding for portions of each of the six viral structural proteins, as well as clones coding for intercistronic sequences. By Northern blotting, we could order the clones according to the pattern of individual gene-specific and readthrough mRNAs. Clones corresponding to the N, P/C and M genes were identified by correlation of the mRNAs with their in vitro translation products; clones corresponding to the H, F and L genes were identified by indirect evidence. The results indicated that the gene order in measles virus is that of a typical paramyxovirus (3'-N,P/C,M,F,H,L-5'), but that the M and F transcripts each contain 1.5 times the coding capacity needed for synthesis of these proteins in vivo.

Cloning, Molecular↗

PubMed1984

Molecular cloning of chromosome I DNA from Saccharomyces cerevisiae: isolation of the ADE1 gene.

The ADE1 gene of Saccharomyces cerevisiae was isolated by complementation in S. cerevisiae from a yeast genomic DNA library carried on plasmid YEp13. Electron microscopy of R-loop-containing DNA indicated the location of the ADE1 gene on the plasmid insert. Gene disruption and gene replacement were used to demonstrate that the ade1-complementing sequence was the actual ADE1 gene that maps on chromosome I. ade1 strains which normally form red colonies form white ones when transformed with the cloned ADE1 gene. This property should be very useful, since it enables detection of plasmids carrying this gene under nonselective conditions.

Chromosomes↗

PubMed1983

Cell saver.

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Blood Cells↗

PubMed1981

Instrumentation needs of research universities.

This article assesses the status of scientific instruments in major research universities and identifies factors that facilitate or impede their development, acquisition, use, and maintenance. Sixteen universities, six national and government laboratories, and nine commercial laboratories were visited; over 700 individuals were interviewed. Data on instrument acquisition and age were collected. Instrumentation was examined in physics, chemistry, biological sciences, earth sciences, and electrical engineering. The study found that the quality of university instrumentation has seriously deteriorated, due principally to a relative decrease in instrumentation funding, inflexibility within the project grant system, and insufficient support for maintenance.

Costs and Cost Analysis↗

PubMed1976

Distribution and removal of human serum albumin-technetium 99m instilled intranasally.

The efficacy of antiviral drugs and vaccines administered intranasally may depend upon the technique of application. The distribution and time-course of removal of human serum albumin-technetium 99m (HSA-Tc 99m)-instilled intranasally were studied in eleven healthy volunteers using a gamma camera and an anterior sodium iodide scintillation detector. In 100 randomized studies material was delivered as drops in the supine position or as a spray to seated subjects. A significantly higher proportion of 'good' distributions (62 in 73 tests) was obtained with drops compared with spray (1 in 27). The volume administered was varied between 0.10 ml and 0.75 ml and the concentration of HSA was changed from 3 to 30% with no significant effect upon the distribution of time-course of removal; pertechnetate in isotonic saline was distributed and removed in a manner comparable to HSA-Tc 99m. Activity recorded by the detector showed an initial rapid fall associated with removal of most of the material from the nasal cavity, followed by a slower decline associated with the removal of material mainly from the anterior region of the nose. A multidose study confirmed that frequent administration by drops is required to maintain a high level of activity in the nasal cavity. Using this technique it should be possible to correlate measurements of antiviral efficacy and vaccines take-rates with certain characteristics of intranasal applicators; such studies may lead to the design of better devices.

Administration, Intranasal↗

PubMedDate not supplied

Factors controlling the dendritic arborization of retinal ganglion cells.

The effects of changing retinal ganglion cell (RGC) density and availability of presynaptic sites on the development of RGC dendritic arbor in the developing chick retina were contrasted. Visual form deprivation was used to induce ocular enlargement and expanded retinal area resulting in a 20-30% decrease in RGC density. In these retinas, RGC dendritic arbors increased in a compensatory manner to maintain the inner nuclear layer to RGC convergence ratio in a way that is consistent with simple stretching; RGC dendritic arbors become larger with increased branch lengths, but without change in the total number of branches. In the second manipulation, partial optic nerve section was used to produce areas of RGC depletion of approximately 60% in the central retina. This reduction in density is comparable to the density of locations in the normal peripheral retina. In RGC depleted retinas, dendritic arbor areas of RGCs in the central retina grow to match the size of normal peripheral arbors. In contrast to the expanded case, two measures of intrinsic arbor structure are changed in RGC-depleted retinas; the branch density of RGC dendrites is greater, and the relative areas of the two arbors of bistratified cells are altered. We discuss the potential roles of retinal growth, local RGC density, and availability of presynaptic terminals in the developmental control of RGC dendritic arbor.

Animals↗