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Biomedical subjects

R R Becker

Publications and source records attributed to R R Becker.

At least 37 records · Page 2Linked to original sources
PubMed1980

Comparison of the Structure of C- and N-Polyhedrins from Two Occluded Viruses Pathogenic for Orgyia pseudotsugata.

C-and N-polyhedrins from a cytoplasmic polyhedrosis virus (a double-stranded RNA virus) and a nuclear polyhedrosis virus (a DNA virus), respectively, of Orgyia pseudotsugata were compared. Although both polyhedrins appear to stabilize their respective virions and have similar molecular weights, they differed in amino acid composition, tryptic peptide elution profiles from a cation-exchange resin, and N-terminal amino acid sequence and showed no antigenic relatedness. This suggests that these two proteins originated independently of one another.

Journal Article↗
PubMed1980

Effects of testosterone and oestrogen on serum prolactin in the androgen-insensitive rat.

Serum prolactin levels in intact, castrated, and castrated adrenalectomized normal and male pseudohermaphrodite (Tfm) rats were compared before and after administering testosterone oenanthate and oestradiol benzoate. Without steroids, castration alone and castration plus adrenalectomy effected a drop in prolactin titres which was greater in the castrated-adrenalectomized rats. Although testosterone did not raise the prolactin titres in any of the animals studied, oestrogen raised them far above normal in all. The fall in prolactin following castration and castration + adrenalectomy could be the result of removal of organs that were producing oestrogen.

Adrenalectomy↗
PubMed1979

Fructose-1,6-bisphosphate aldolase from Vibrio marinus, a psychrophilic marine bacterium.

Fructose-1,6-bisphosphate aldolase (Fru-P2A) from a psychrophilic marine bacterium was found to be Class II aldolase based on activation by K+, activation by divalent cations, inactivation by EDTA, low molecular weight, and similar values for Km, Vmax, and Arrhenius activation energy. This enzyme was not markedly different in amino acid composition from the enzymes from mesophilic and thermophilic organisms, yet it has unusual thermal properties.

Amino Acids↗
PubMed1979

Tryptic peptide analysis and NH2-terminal amino acid sequences of polyhedrins of two baculoviruses from Orgyia pseudotsugata.

Comparative analysis of the tryptic peptides and terminal amino acid sequence was made on polyhedrins from two genetically different baculoviruses that are naturally pathogenic for the same insect host. Comparison of the tryptic peptides of the nucleopolyhedrosis bundle virus and nucleopolyhedrosis single-rod virus of Orgyia pseudotsugata by means of cation-exchange resins indicated that the proteins have a closely related amino acid sequence. The NH(2)-terminal amino acid sequence of polyhedrins from the two viruses differed in only 4 out of 34 amino acids. The nucleopolyhedrosis bundle virus and the nucleopolyhedrosis single-rod virus also differed in 4 and 5 out of 34 terminal amino acids, respectively, from the sequence reported for polyhedrin of a baculovirus of Bombyx mori [Serebryani, S. B., Levitina, T. L., Kautsman, M. L., Radavski, Y. L., Gusak, N. M., Ovander, M. N., Sucharenko, N. V. & Kozlov, E. A. (1977) J. Invertebr. Pathol. 30, 442-443]. In addition, the nucleopolyhedrosis single-rod virus had two amino acids (Met-Tyr) on the NH(2) terminus that were not present on the terminus of nucleopolyhedrosis bundle virus or B. mori baculovirus polyhedrin. Approximately half (six) of the total tyrosine residues are clustered in the terminal 20 amino acids of the polyhedrins. Secondary structures predicted from the primary sequence suggest that the tyrosines are clustered in two areas. This nonrandom distribution and the pK(a) of about 10 for tyrosine may be related to the alkali solubility of the polyhedrin.

Amino Acid Sequence↗
PubMed1979

Tyrptic peptide compositions of hemoglobins from mink (Mustela vison) and hyena (Hyaenae hyaenae) and the alpha-chain of coatimundi (Nasua nasua).

The amino acid composition of the tryptic peptides from hyena hemoglobin, two hemoglobins of the mink and the alpha-chain of coatimundi have been determined, allowing comparison with data previously obtained from other carnivores. The two hemoglobins of mink differ at only one amino acid residue, alpha 15, which is glycyl in one hemoblobin and aspartyl in the other.

Amino Acids↗
PubMed1978

Comparative effectiveness of directive vs. nondirective group therapist style on client problem resolution.

This study was designed to determine the utility of two newly developed self-report measures of group therapy effectiveness. Repeated administrations of these instruments indicated that group therapy was effective in inducing significant problem resolution and that these changes were stable on a 3-month follow-up. One of the measures also suggested that the nondirective style of therapy appeared to be more effective than the directive style. Results suggest that two self-report measures may be useful in studies designed to determine both the outcome as well as the process of group psychotherapy.

Adult↗
PubMed1978

Hormonal factors related to the incidence of testicular tumors in male pseudohermaphrodite rats.

Pieces of testicular tumor from male pseudohermaphrodite (tfm) rats were transplanted between the skin and body wall musculature of 4-day-old female, male, and tfm hosts and to the anterior chambers of the eyes of gonadectomized and intact adult tfm, female, and male hosts. These transplants grew in all hosts except normal males. To determine whether these tumors were hormone-dependent, the levels of circulating gonadotropins were measured in all host types to ascertain which were low in the males and high in all of the others. Prolactin, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels were measured in intact and castrated normal and tfm rats. Normal males had low levels of prolactin, estrogen, LH, and FSH; however, transplants grew well in other hosts with low titers of these hormones. Except for normal males, all hosts had high serum levels of LH. Thus, testicular tumors in tfm rats appear to be LH-dependent.

Animals↗
PubMed1978

Amino acid sequence of the hemoglobin of raccoon (Procyon lotor).

The amino acid sequences of the hemoglobin alpha- and beta-chains of raccoon have been determined by a combination of manual and automatic sequencing procedures. The raccoon beta-chain shows 16 amino acid differences from that of dog. The alpha chain shows 10 differences. These values are identical with those predicted by analogy from their tryptic peptide compositions.

Amino Acid Sequence↗
PubMed1976

The purification and properties of the glutamine synthetase from the cytosol of Soya-bean root nodules.

The major portion of glutamine synthetase activity in root nodules of soya-bean plants is associated with the cytosol rather than with Rhizobium japonicum bacteroids. Glutamine synthetase accounts for about 2% of the total soluble protein in nodule cytosol. Glutamine synthetase from nodule cytosol has been purified by a procedure involving fractionation with protamine sulphate, ammonium sulphate and polypropylene glycol, chromatography on DEAE-Bio-Gel A and Bio-Gel A-5m and affinity chromatography on glutamate-agarose columns. The purified preparation appeared to be homogeneous in the analytical ultracentrifuge. From sedimentation-equilibrium experiments a mol. wt. of about 376000 was determined for the native enzyme and 47300 for the enzyme in guanidinium chloride. From these data and measurements of electron micrographs, we have concluded that glutamine synthetase from nodule cytosol consists of eight subunits arranged in two sets of planar tetramers which form a cubical configuration with dimensions of about 10 nm (100 A) across each side. Glutamine synthetase from nodule cytosol has a higher glycine and proline content and a lower content of phenylalanine than the glutamine synthetase that has been prepared from pea seed. The cytosol enzyme contains four half-cystine molecules per subunit, which is in contrast with two reported for the enzyme from pea seed. Enzyme activity is striking influenced by the relative proportion of Mg2+ and Mn2+ in the assay medium. Activity is inhibited by feedback inhibitors and is influenced by energy charge.

Amino Acids↗