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J K Dyer

Publications and source records attributed to J K Dyer.

48 records · Page 3Linked to original sources
PubMed1977

Fermentation of L-aspartate by a saccharolytic strain of Bacteroides melaninogenicus.

Resting cells of Bacteroides melaninogenicus fermented L-[14C]aspartate as a single substrate. The 14C-labeled products included succinate, acetate, CO2, oxaloacetate, formate, malate, glycine, alanine, and fumarate in the relative percentages 68, 15, 9.9, 2.7, 1.8, 1.0, 0.7, 0.5, and 0.06, respectively, based on the total counts per minute of the L-[14C]aspartate fermented. Ammonia was produced in high amounts, indicating that 96% of the L-aspartate fermented was deaminated. These data suggest that L-aspartate is mainly being reduced through a number of intermediate reactions involving enzymes of the tricarboxylic acid cycle to succinate. L-[14C]asparagine was also fermented by resting cells of B. melaninogenicus to form L-aspartate, which was subsequently, but less actively, fermented.

Amino Acids↗
PubMed1976

Influence of amino acids on the growth of Bacteroides melaninogenicus.

Addition of individual amino acids to a Trypticase-yeast extract-hemin medium affected growth rates and final yields of an asaccharolytic strain and a saccharolytic strain of Bacteroides melaninogenicus. L-Aspartate or L-asparagine produced maximal growth enhancement for both strains. L-[14C]aspartate was fermented by resting cells of the asaccharolytic strain. L-Cysteine or L-serine also enhanced growth for the saccharolytic strain. However, growth of the saccharolytic strain was inhibited by L-lysine, L-glutamate, L-glutamine, L-isoleucine, L-leucine, and L-proline; growth of the asaccharolytic strain was inhibited by DL-valine and L-serine. Both strains were inhibited by L-histidine, DL-methionine, L-tryptophan, L-arginine, and glycine.

Amino Acids↗
PubMed1975

Acute renal failure following operation for aortic aneurysm.

Thirty-eight patients with acute renal failure following operation for aortic aneurysm were analyzed retrospectively in search of predictors of survival. Of 14 potential predictor variablesonsidered, none taken singly were significant; however, the combination of age, operative interruption of renal blood flow and prior renal dysfunction served as a significant predictor, p less than 0.05. Low survival rates occurred if the patient was over 70 years of age, if renal blood flow required interruption or if preoperative renal impairment was present. High survival rates occured in patients less than 70 years of age who had no interruption of renal blood flow and who had normal preoperative renal function. Although the total mortality rate of these patients with acute renal failure was 61 per cent, only one of 12 patients with favorable prognostic indicators died. Acute renal failure following aortic aneurysm repair has no worse prognosis that that stated in the literature for acute renal failure following other surgical procedures. A virorous therapeutic approach should be maintained despite the advent of complications.

Acute Kidney Injury↗
PubMed1970

2,4-diaminovaleric acid: an intermediate in the anaerobic oxidation of ornithine by Clostridium sticklandii.

The oxidation of ornithine in the presence of proline by crude extracts of Clostridium sticklandii cells was stimulated by nicotinamide adenine dinucleotide, coenzyme A, alpha-ketoglutarate, dimethylbenzimidazolyl cobamide (DBC) coenzyme, MgCl(2), and adenosine diphosphate. Deletion of various cofactors resulted in the accumulation of a new dibasic amino acid which was identified as 2,4-diaminovaleric acid. Both the oxidation of ornithine to alanine and acetate and the conversion of ornithine to 2,4-diaminovaleric acid were stimulated by addition of DBC coenzyme, and both were inhibited by intrinsic factor, an inhibitor of cobamide coenzyme-dependent reactions. This inhibition was reversed by addition of DBC coenzyme. However, the oxidation of 2,4-diaminovaleric acid was insensitive to added intrinsic factor. The data indicate that 2,4-diaminovaleric acid represents the first intermediate in the oxidation of ornithine by C. sticklandii.

Acetates↗
PubMed1968

Isolation and role of nonheme iron protein in Clostridium botulinum.

A type of iron-bound protein was isolated from Clostridium botulinum by a modification of the method used for isolating ferredoxin from C. pasteurianum. This method involved acetone and diethylaminoethyl cellulose treatments followed by ammonium sulfate fractionation. The protein exhibited maximal absorption in the ultraviolet region near 260 mmu. Portions of the isolated iron protein were separated by disc electrophoresis and, following specific iron-bound protein staining, showed a positive reaction in the same position on the gel column as was first demonstrated by use of cell-free extract. Evidence accumulated by use of a cell-free extract of C. botulinum suggests that pyruvate is metabolized through a phosphoroclastic system as demonstrated in other clostridia. It is probable that ferredoxin is an electron mediator between pyruvic oxidase and hydrogenase for hydrogen evolution and acetyl phosphate formation.

Bacterial Proteins↗
PubMed1968

Fermentation of ornithine by Clostridium sticklandii.

Resting cells of Clostridium sticklandii fermented l-ornithine as a single substrate by a coupled oxidation-reduction with proline as the electron acceptor. The products of the fermentation of ornithine alone were ammonia, alanine, acetate, and delta-aminovalerate, in order of concentration. Traces of CO(2), butyrate, and proline were also found. When an equimolar amount of proline was added along with ornithine, very little delta-aminovalerate was produced from the ornithine, but essentially all of the proline was reduced to this compound. The ratios of the other primary products were changed by the addition of proline. The primary products from ornithine fermented in the presence of proline were acetate, ammonia, alanine, and CO(2), in order of concentration. Studies with dl-ornithine-1-(14)C, dl-ornithine-2-(14)C, and dl-ornithine-5-(14)C demonstrated that the primary cleavage of this amino acid occurred between carbons 3 and 4. A high percentage of the isotope from carbons 1 and 2 was found in alanine, and most of that from carbon 5 was found in volatile acid. The CO(2) formed was derived from the carboxyl carbon. All of the radioactivity from the fermentation of dl-alanine-1-(14)C was found in (14)CO(2). The alanine from ornithine was oxidized by d-amino acid oxidase to the same extent as dl-alanine, indicating that it was dl-alpha-alanine. Preliminary experiments with cell extracts indicated proline is an intermediate in the reduction of ornithine to delta-aminovaleric acid.

Alanine↗
PubMed1966

Radiation survival of food pathogens in complex media.

When 15 bacterial species representing genera associated with food-borne diseases were irradiated individually, all except Escherichia coli and Streptococcus faecalis showed typical linear dose-survival curves in Hartsell's broth. The minimal lethal dose (MLD) for the organisms tested ranged from 3.0 x 10(5) to 6.0 x 10(5) rad. Salmonella paratyphi B, S. wichita, S. typhi, E. coli, and S. faecalis were found to be the least sensitive to radiation. In commercially canned crabmeat the survival curves of S. typhi, S. paratyphi B, and S. wichita exhibited to varying degrees an initial linear death decline with increasing radiation doses, followed by a distinct tailing effect caused by survival of low numbers at the higher doses. The above species of Salmonella were further individually subjected to gamma-radiation in various dilutions of crabmeat. The "tailing effect" gradually disappeared, with the dose-survival curve tending to become linear as the concentration of the crabmeat decreased.

Crustacea↗
PubMedDate not supplied

Identification and characterization of species of the family Bacteriodaceae by polyacrylamide gel electrophoresis.

Polyacrylamide gel electrophoresis was used to compare protein profiles of members of the family Bacteriodacceae. Cell-free extracts were prepared and the protein components separated by multistage polyacrylamide gel electrophoresis. The profiles were distinct and reproducible thus allowing identification of species, subspecies, and minor strain differences. Lyophilization of the cell-free extracts did not alter the major protein components. The results indicate that the techniques used may be useful in conjunction with conventional tests in identification at the species level.

Bacteroidaceae↗