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T I Matula

Publications and source records attributed to T I Matula.

28 records · Page 2Linked to original sources
PubMed1979

Detection of the mutagenic activity of lead chromate using a battery of microbial tests.

The potential mutagenicity of the carcinogen lead chromate was tested by the following battery of microbial tests: the Escherichia coli PolA+/PolA- survival test; the Salmonella/microsome His+ reversion assay; the E. coli Trp+ reversion test as a plate assay; the E. coli Gal+ forward mutation test; and the Saccharomyces cerevisiae assay for mitotic recombination. Lead chromate is mutagenic in Salmonella and in Saccharomyces and is thus identified as a microbial mutagen by this battery. Metabolic activation by rat liver homogenate (S9) is not required for the mutagenic activity of lead chromate. The most statistically significant, positive result is found with a supplementary assay, the E. coli fluctuation test. To determine whether the lead ion and/or the chromate ion were responsible for the mutagenicity observed, lead chloride and chromium trioxide (chromic acid) were also tested. In E. coli fluctuation test, the ranges of maximal mutagenicity for chromium trioxide and lead chromate overlap at the concentration 10(-5)M, whereas lead chloride shows no mutagenicity and little lethality at concentrations up to 10(-3)M. Thus, it appears that the chromate ion is responsible for the mutagenicity of lead chromate.

Chromates↗
PubMed1979

Mutagenic activity of rhodamine dyes and their impurities as detected by mutation induction in Salmonella and DNA damage in Chinese hamster ovary cells.

Commercial rhodamine dyes 6G and B induce His+ reversion mutations in Salmonella and single-strand breaks in Chinese hamster ovary cells, as detected by alkaline sucrose sedimentation. Aroclor 1254-induced rat liver homogenate (S9) is required for production of genetic activity by these dyes. Rhodamine 6G induces both frameshift and base substitution mutations, whereas rhodamine B induces only frameshift mutations. Rhodamine 6G is genetically more active and more toxic than is rhodamine B in both the bacterial and mammalian assays. Rhodamine 6G and B induce doublings of His+ revertants in Salmonella at the doses of 0.02 and 0.52 mumol/plate and shifts in the molecular weight of Chinese hamster ovary DNA at concentrations of 9 x 10(-5) and 9 x 10(-4) M, respectively. All genetic effects assayed demonstrate dose-related increases. Further testing of the pure dyes in Salmonella revealed that rhodamine B loses most of its mutagenicity with purification, whereas rhodamine 6G does not. Impurities from commercial rhodamine B demonstrate the same extent of mutagenicity as the commercial dye.

Animals↗
PubMed1970

Transport and retention of K+ and other metabolites in a marine pseudomonad and their relation to the mechanism of optical effects.

Suspensions of cells of a marine pseudomonad washed with 0.05 m MgSO(4) showed an immediate increase in optical density (first-phase optical change) when the salt concentration of the suspending medium was increased; a subsequent slow decrease in optical density (second-phase optical change) occurred if K(+) was present. The rate of the second-phase change was similar to the rate of uptake of (42)K(+) by the cells. Glutamate increased the rate and extent of the second-phase change and produced a parallel increase in the rate and extent of uptake of (42)K(+). Citrate increased the extent of the second-phase change in cells adapted to oxidize citrate but not in unadapted cells. Adapted, but not unadapted, cells accumulated (14)C-citrate. The nonmetabolizable alpha-aminoisobutyric acid (AIB) also increased the extent of the second-phase change under conditions leading to the uptake of (14)C-AIB by the cells. Cells maintained in a salt solution optimal for the retention of intracellular solutes were found to contain 0.184 m K(+). In the same salt solution, cells preloaded with (42)K(+) retained the isotope, but they lost it rapidly when suspended in 0.05 m MgSO(4). The second-phase changes can be accounted for by the energy-dependent accumulation in an osmotically active form of K(+) and other metabolites by cells depleted of intracellular solutes.

Aminoisobutyric Acids↗
PubMed1969

Mechanism of optical effects in suspensions of a marine pseudomonad.

When cells of a marine pseudomonad washed free of medium components with 0.05 m MgSO(4) were suspended in solutions containing 200-mm concentrations of various salts, there was an immediate increase in optical density (OD), followed by a slow decrease. The decrease following the initial increase, but not the increase itself, could be prevented by omitting K(+) from or by adding metabolic inhibitors to the suspending solution. With NaCl, the initial increase in OD rose to a maximum as the salt concentration was increased to 200 mm and then declined at 500 mm. There was a corresponding decrease in intracellular fluid volume to a minimum at 200-mm NaCl and then a rise. When the increased OD produced by NaCl was maintained, the internal Na(+) and Cl(-) could be shown to have reached essentially the same concentration in the cells as in the medium. Thus, the OD changes could not have been due to osmotic effects. No evidence was obtained of a salt-induced aggregation of nuclear material. The OD of suspensions of isolated cell envelopes increased in response to increases in NaCl concentration in the absence but not in the presence of 0.05 m MgSO(4). The data was interpreted to indicate that the salt-induced increases in OD occurring in suspensions of the cells resulted from an interaction of salts with components of the cell envelope, causing contraction of the envelopes and shrinkage of the cells.

Chlorides↗
PubMed1969

Penetration of Pseudomonas aeruginosa by sodium chloride and its relation to the mechanism of optical effects.

When cells of Pseudomonas aeruginosa were suspended in solutions containing increasing concentrations of NaCl, the optical density (OD) of the suspensions measured within 30 sec was found to increase in proportion to the increase in salt concentration. Measurement of intracellular fluid volumes indicated that the volume of the cells decreased roughly in proportion to the increase in salt concentration. After the initial increase in optical density, there was a slow decrease at all concentrations of NaCl tested except the highest, 500 mm. Metabolic inhibitors such as sodium azide and 2,4-dinitrophenol prevented the decrease. Direct analysis showed that the Na(+) and Cl(-) concentrations in the cells were 86 and 77%, respectively, of the concentrations of the ions in the suspending medium after 1 hr. Measurement of the (22)Na space in packed cells showed that Na(+) penetrated the total fluid space in the packed cells. The penetration of (22)Na was not prevented by the presence of metabolic inhibitors or by 500 mm NaCl in the suspending medium. The results indicate that the OD increases produced in suspensions of P. aeruginosa by NaCl are not due to the osmotic action of the salt. The subsequent optical density decreases observed are under metabolic control.

Azides↗
PubMed1967

Nutrition and metabolism of marine bacteria. XVI. Formation of protoplasts, spheroplasts, and related forms from a gram-negative marine bacterium.

When cells of a marine pseudomonad were washed and suspended in 0.5 m sucrose, they retained their rod shape, but thin sections, when examined in an electron microscope, revealed that the outer layer of the cell wall had separated a considerable distance from the cytoplasmic membrane. Treatment of such cells with lysozyme alone produced no obvious change, but treatment with ethylenediaminetetraacetic acid (EDTA) alone caused the outer wall to disappear. A combination of EDTA and lysozyme resulted in the rapid formation of spheres essentially free from hexosamine and indistinguishable from protoplasts of gram-positive bacteria. When cells were washed with 0.5 m NaCl and then suspended in 0.5 m sucrose, they also retained their rod shape, but in this case the outer layer separated from the cells completely and could be recovered from the suspending medium. Such cells were converted to protoplasts by the action of lysozyme alone. Cells washed and finally suspended in 0.5 m NaCl, when treated with EDTA and lysozyme, slowly became spherical. Thin sections revealed typical spheroplasts of gram-negative bacteria in which the outer wall remained intact. Protoplasts took up alpha-aminoisobutyric acid by a Na(+)-dependent process.

Aminoisobutyric Acids↗
PubMed1966

Nutrition and metabolism of marine bacteria. XV. Relation of Na+-activated transport to the Na+ requirement of a marine pseudomonad for growth.

Drapeau, Gabriel R., (McGill University, Montreal, Quebec, Canada), Tibor I. Matula, and Robert A. MacLeod. Nutrition and metabolism of marine bacteria. XV. Relation of Na(+)-activated transport to the Na(+) requirement of a marine pseudomonad for growth. J. Bacteriol. 92:63-71. 1966.-A marine pseudomonad was found to require 50 to 100 mm Na(+) for maximal rate of oxidation of d-galactose and for the transport of d-fucose-H(3) into the cells. The same organism required 150 to 200 mm Na(+) for the oxidation of l-alanine and for the transport of phi-aminoisobutyric acid-C(14) (AIB-C(14)) into the cells. Competition studies indicated that d-galactose and d-fucose on the one hand and l-alanine and AIB on the other shared common carriers for transporting the compounds into the cells. This parallelism in Na(+) response for oxidation and transport extended to growth when l-alanine was the sole carbon source in the medium. When d-galactose was the sole carbon source, an amount of Na(+) equal to that with l-alanine was needed. KCN and dinitrophenol but not ouabain inhibited the uptake of AIB-C(14) by the cells. K(+) in addition to Na(+) was required for transport, and both Mg(++) and either Cl(-) or Br(-) were stimulatory. Photobacterium fischeri was also found to require Na(+) specifically for the uptake of AIB-C(14) by the cells.

Alanine↗
PubMedDate not supplied

Genetic toxicity of erythrosine in yeast.

The genetic activity of erythrosine, a fluorescein dye used as a color additive, was studied in assays with growing cells of different strains of Saccharomyces cerevisiae. Erythrosine induced mitotic gene conversion and reverse mutation in strains D7 and XV185-14C of yeast. It failed, however, to increase mitotic recombination in strain D5. These results show that erythrosine possesses genotoxic activity for eukaryotic cells.

Erythrosine↗
PubMedDate not supplied

A multiple end-point approach to evaluation of cytotoxicity and genotoxicity of erythrosine (FD and C Red No. 3) in a V79 hepatocyte-mediated mutation assay.

V79 Chinese hamster lung cells were used to evaluate in vitro the cytotoxicity and genotoxicity of erythrosine (2', 4', 5', 7'-tetraiodofluorescein disodium salt; FD and C Red No. 3), a color additive used widely in foods, drugs and cosmetics. Erythrosine reduced colony size at 200 micrograms/ml and was lethal to 90% or more of the cells at 400 micrograms/ml. At dose levels of 100, 200 and 300 micrograms/ml of medium, erythrosine was non-mutagenic to V79 cells at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) and sodium, potassium ATPase (Na+, K+ -ATPase) gene loci and did not increase the frequency of sister-chromatid exchanges with or without rat hepatocyte-mediated activation. Erythrosine at 300 micrograms/ml, unlike lower dose levels, produced an increase in micronucleus frequency in the absence of hepatocytes. An erythrosine dose-related increase in the mitotic frequency was due to an increase in the number of first mitoses at the expense of later cell divisions. Hepatocytes moderated the effect of erythrosine treatment on micronucleus frequency, mitotic frequency and MII/MI ratio. These results demonstrate the advantage of a multiple end-point approach to the evaluation of cytotoxicity and genotoxicity within a single-assay system.

Animals↗