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Biomedical subjects

D Birnbaum

Publications and source records attributed to D Birnbaum.

At least 307 records · Page 17Linked to original sources
PubMed1985

Transformation of Candida maltosa and Pichia guilliermondii by a plasmid containing Saccharomyces cerevisiae ARG4 DNA.

Saccharomyces cerevisiae, Candida maltosa and Pichia guilliermondii have been transformed by the plasmid pYe(ARG4)411, which contains the S. cerevisiae ARG4 gene inserted into pBR322. In all transformants argininosuccinate lyase as well as beta-lactamase were detected. The ARG+ phenotype of transformants is mitotically unstable. Closed circular pYe(ARG4)411 DNA was detected in transformant DNA preparations by hybridization to pBR322 DNA and by transformation of E. coli to ampicillin resistance.

Candida↗
PubMed1985

[Characteristics of mitochondrial DNA from Candida spec. EH15].

The restriction endonucleases EcoRI, PstI and BglII were used to digest the mitochondrial DNA from Candida spec. EH 15. Molecular masses of single digested DNA fragments were calculated. The mitochondrial DNA size (28-30 x 10(6) D) comprises 2/3 of the mitochondrial DNA from Saccharomyces cerevisiae.

Candida↗
PubMed1984

Mode of action of glyphosate in Candida maltosa.

The broad-spectrum herbicide glyphosate inhibits the growth of Candida maltosa and causes the accumulation of shikimic acid and shikimate-3-phosphate. Glyphosate is a potent inhibitor of three enzymes of aromatic amino acid biosynthesis in this yeast. In relation to tyrosine-sensitive 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase and dehydroquinate synthase, the inhibitory effect appears at concentrations in the mM range, but 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase is inhibited by micromolar concentrations of glyphosate. Inhibition of partially purified EPSP synthase reaction by glyphosate is competitive with respect to phosphoenolpyruvate (PEP) with a Ki-value of 12 microM. The app. Km for PEP is about 5-fold higher and was 62 microM. Furthermore, the presence of glyphosate leads to derepression of many amino acid biosynthetic enzymes.

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed1984

Analysis of hospital infection surveillance data.

How often infection rates should be calculated and how large a change is required for "significance" are pertinent questions in nosocomial infection surveillance programs. A method is presented which establishes outbreak threshold infection frequencies. Comparison is direct and immediate: computation of rates or use of electronic data processing is not required. We have validated this method, using computer systems, by comparing the distributions of mean weekly incidence and prevalence statistics for each ward by nosocomial infection site in an acute care general hospital against both our theoretical outbreak threshold limits and the distribution of proven infection outbreaks. Sensitive and specific distinction between random variation or sporadic cross-infection and true persisting outbreaks requiring intervention is obtained. This approach provides a simple and timely alternative to intuitive after-the-fact interpretation of infection patterns which is applicable to infection surveillance and cost-effective infection control in hospitals of all sizes.

British Columbia↗
PubMed1984

New human transforming genes detected by a tumorigenicity assay.

We have developed a sensitive bioassay for transforming genes based on the tumorigenicity of cotransfected NIH3T3 cells in nude mice. The assay differs substantially from the NIH3T3 focus assay. Using it, we have detected the transfer of three transforming genes from the DNA of MCF-7, a human mammary carcinoma cell line. One of these is N-ras, which is amplified in MCF-7 DNA. The other two, which we have called mcf2 and mcf3, do not appear to be related to known oncogenes. We cannot detect their transfer by using the NIH3T3 focus assay. We do not yet know whether either mcf2 or mcf3 is associated with genetic abnormalities in MCF-7 cells.

Animals↗
PubMed1984

Absolute dependence of phenylalanine and tyrosine biosynthetic enzyme on tryptophan in Candida maltosa.

Candida maltosa synthesizes phenylalanine and tyrosine only via phenylpyruvate and p-hydroxyphenylpyruvate. Tryptophan is absolutely necessary for the enzymatic reaction of chorismate mutase and prephenate dehydrogenase; activity of prephenate dehydratase can be increased 2.5-fold in the presence of tryptophan. Activation of the chorismate mutase, prephenate dehydratase and prephenate dehydrogenase by tryptophan is competitive with respect to chorismate and prephenate with Ka 0.06mM, 0.56mM and 1.7mM. In addition tyrosine is a competitive inhibitor of chorismate mutase (Ki = 0.55mM) and prephenate dehydrogenase (Ki = 5.5mM).

Candida↗
PubMed1983

Mouse monoclonal anti-Ia antibodies recognize cross-reacting determinants expressed on distinct subsets of human Ia-like cell-surface molecules.

Human Ia-like cell-surface molecules from a homozygous HLA-DR (6/6) B lymphoblastoid cell line have been analyzed using five mouse anti-Ia m.Ab cross-reacting with HLA-DR antigens. The surface-iodinated molecules immunoprecipitated by these m.Ab were analyzed by SDS-PAGE under reducing conditions and by SDS-PAGE followed by isoelectrofocusing. As read from the different migration patterns, three distinct combinations of human Ia-like molecules were identified by these m.Ab. Three anti-I-E-reactive m.Ab immunoprecipitated two-chain molecules whose apparent mol. wt (32K, 29K) corresponded to those of the classical HLA-DR antigens. One m.Ab which on mouse cells recognized a determinant shared by the I-A and I-E molecules precipitated not only the 32-29K bands, but also a 26K band from human cell extracts. Finally, an I-A reactive m.Ab precipitated a complex set of polypeptides including in addition to the 32-29K bands, three additional chains of 30, 28 and 26K. Sequential immunoprecipitation demonstrated that removal of the classical 29-32K HLA-DR chains by an anti-I-E m.Ab did not affect the subsequent immunoprecipitation of the additional chains by the anti-I-A or the anti-I-A + I-E m.Abs. These patterns and those obtained by 2D-gels analysis which demonstrated the complexity of the 26K band are compatible with the coexpression of at least three different subsets of molecules: (1) Ia-like molecules of 29-32K, recognized by all the m.Ab used; (b) molecules of 28-30K recognized by the anti-I-A m.Ab and (c) molecules apparently constituted by 26K chains, precipitated by the anti-I-A m.Ab and by the anti-I-A + I-E m.Ab.

Animals↗
PubMed1983

The importance of cross-reactions between species: mouse allo-anti-Ia monoclonal antibodies as a powerful tool to define human Ia subsets.

Three mouse allo-anti-Ia monoclonal antibodies recognizing epitopes specific for either I-E gene products (H81.98.21 and H40.315.7 Mabs) or shared between I-E and I-A gene products (H82.246.3 Mab) were used to analyze the human Ia molecules against which they cross-react. The results indicated that in the Ia pool of the human B cell line Raji the three Mabs were able to recognize at least three distinct subsets differing each other both in their alpha as well as in their beta subunits. The comparison with the previously defined human Ia subsets NG1, NGe, and DC1 suggested the following similarities: H81.98.21 specific Ia molecules similar to NG1; H82.246.3 specific Ia molecules similar to NG2, and including probably NG1; H40.315.7 specific molecules similar to DC1 in their alpha subunits and probably heterogeneous in their beta subunits with characteristics of the DC1, NG1, and NG2 subunits altogether. The heterogeneity of the human Ia molecules and the possible similarities with the mouse Ia system were discussed.

Animals↗
PubMed1983

Psychological reality of cross-media artistic styles.

The sensitivity of artistically naive people to cross-media styles (baroque, neoclassic, and romantic) and to period styles (works composed by artists born during the same epoch) in four media (painting, poetry, music, and architecture) was assessed. In two studies, adult subjects tended spontaneously to sort stimuli according to both cross-media styles and period styles. In a third study, nursery school children were shown to be able to sort pictures of paintings and architectural facades on the basis of cross-media styles. Other experiments using rating scales again demonstrated that artistically naive adults are sensitive to both cross-media styles and period styles even when they are not implicitly urged to disregard medium. These and other studies using rating scales suggested that the bases for discrimination of both cross-media styles and period styles are the dimensions of realistic versus unrealistic and of overall arousal potential.

Architecture↗
PubMed1982

Serological cross-reactivity between products of separate I regions.

A B10.S(7R) anti-B10.S(9R) serum (anti-IJEkCd) contained, as expected, antibodies specific for the I-E-subregion-encoded determinant Ia.7. However, tests on recombinant haplotypes demonstrated a series of unexpected weak extrareactions which could be interpreted to be directed against antigenic determinants encoded in the I-A subregion of the H-2 complex. The same type of extrareaction was observed in eluates from I-As, I-Ek cells coated with A.TH anti-A.TL (I-As, I-Ek anti-I-Ak, I-Ek) serum. This reactivity in serum and eluates could be interpreted as cross-reactivity between products of the I-E and I-A subregions.

Animals↗