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R M HERRIOTT

Publications and source records attributed to R M HERRIOTT.

At least 19 recordsLinked to original sources
PubMed1963

ULTRAVIOLET IRRADIATION OF NATIVE AND DENATURED TRANSFORMING DEOXYRIBONUCLEIC ACID FROM HAEMOPHILUS INFLUENZAE.

Cabrera-Juarez, Emiliano (Johns Hopkins University School of Hygiene and Public Health, Baltimore, Md.) and Roger M. Herriott. Ultraviolet irradiation of native and denatured transforming deoxyribonucleic acid from Haemophilus influenzae. J. Bacteriol. 85:671-675. 1963.-Two antibiotic-resistance markers in denatured deoxyribonucleic acid (DNA) from Haemophilus influenzae showed about the same sensitivity to ultraviolet irradiation as in native DNA. The resistance of markers in denatured DNA to ultraviolet (UV) light increases with alkalinity up to pH 12. New transforming markers or genetic "lethals" were not produced by in vitro irradiation of either native or denatured DNA. The UV irradiation of the denatured DNA reduces its capacity to form new markers with nitrous acid. Nitrous acid reactivated some of the intrinsic marker destroyed by UV irradiation of denatured transforming DNA.

DNA↗
PubMed1962

Inactivation of the T-even coliphages by pyrophosphate.

Van Vunakis, Helen (Brandeis University, Waltham, Mass.) and Roger M. Herriott. Inactivation of the T-even coliphages by pyrophosphate. J. Bacteriol. 83:590-596. 1962.-Pyrophosphate liberates the deoxyribonucleic acid from the T-even coliphages. The reaction is dependent on pH, temperature, time, and ionic environment. The reaction can be inhibited by magnesium, putrescine, spermidine, and neutral molecules above a certain molecular weight. Possible mechanisms of the reaction are discussed.

Bacteriophages↗
PubMed1962

Pepsinogen and pepsin.

Evidence relating to the structure and properties of swine pepsinogen and pepsin has been reviewed and used to suggest a tentative two dimensional picture of the skeleton of these two proteins. When pepsinogen, a folded single peptide chain, is converted to pepsin, there is a profound change in the physical and chemical properties of the protein. In an as yet unknown manner, except that it is initiated by a peptic cleavage of the protein chain, a single enzymic site is formed. This site is made up, quite probably, of the secondary carboxyl group of glutamic acid or of aspartic acid and a tyrosine phenol group in close proximity so that they can form hydrogen or hydrophobic bonds with the substrate in some unique manner that permits hydrolysis to occur at an accelerated rate.

Animals↗
PubMed1961

Infectious nucleic acids, a new dimension in virology.

Viral nucleic acids have been found to be infectious for tissues and animals, yet are nonantigenic and resistant to antibodies against whole virus. Other unique properties, such as their host range and their susceptibility to nuclease action, render them a wholly new dimension to be reckoned with in virology. These properties may explain a number of conditions which at present are considered anomalous. The release from infected tissues of even a small proportion of total virus as free nucleic acid could, in an otherwise immune individual, lead to a low level of infection which would, perhaps, explain permanent immunity. If the proportion of nucleic acid is higher, or if the nucleic acid is resistant to nucleases because of an inert envelope, such conditions as "carrier" states-that is, viremias with or without antibodies-are possible. Note added in proof: The recent article by J. D. Ebert and F. H. Wilt (54) came to my attention after the present article was written. Ebert and Wilt's excellent article indicates the impact of the newer knowledge of viral nucleic acids on the ideas developing in the field of embryology.

Animals↗
PubMed1961

Studies on transformations of Hemophilus influenzae. I. Competence.

A procedure has been developed for obtaining Hemophilus influenzae of such competence that 1 to 10 per cent transform to any of several genetic factors by utilizing a period of aerobic growth followed by a non-aerobic period. Differences in levels of competence were not due to differences in genetic background. Competence was due to at least one factor intrinsic to the cell or site on the cell and was not transferable to non-competent cells. Competence was affected by salt concentration, pH, and temperature. Washing competent cells reduces their ability to transform, but not their capacity to bind DNA reversibly. The irreversible step could be restored with little or no accompanying growth. These facts suggest that reversible and irreversible binding represent separate biochemical steps. DNA initiates a reaction in cells leading to a loss of competence. In the absence of DNA the cells remain competent for at least an hour. Competence correlates quantitatively with predictability of multiple transformations. The observed and calculated values of multiple transformations are in closer agreement, the higher the frequency of transformation for single markers. The correction needed to bring the two figures into agreement is a measure of the fraction of non-competent cells.

DNA, Bacterial↗
PubMed1961

Studies on transformations of Hemophilus influenzae. II. The molecular weight of transforming DNA by sedimentation and diffusion measurements.

The sedimentation and diffusion coefficients have been determined for Hemophilus influenzae transforming activity and DNA using P(32)-labeled DNA. The methods employed the Spinco fixed boundary separation cell for measurements of the sedimentation coefficient and the Northrop-Anson diffusion cell to determine the diffusion coefficient. There was a very close correlation between the amount of DNA and transforming activity sedimented or diffused. The sedimentation coefficient (s(20 degrees )), for both biological activity and DNA was 27 and the diffusion coefficient (D(20 degrees )) 1 x 10(-8) cm(2)/sec. The molecular weight calculated from these coefficients gave a value of 16 million. There was no difference in the sedimentation coefficients for the two unlinked markers, streptomycin and erythromycin resistance, and the diffusion coefficients for single markers or the linked markers, streptomycin and cathomycin, were the same.

DNA↗
PubMed1961

Studies on transformations of Hemophilus influenzae. III. The genotypes and phenotypic patterns of three streptomycin-resistant mutants.

A general method of determining the nature of the genotypes in mutants of transformable bacteria with similar phenotypes is discussed. The method is used to identify the genotypic patterns of three mutants of Hemophilus influenzae which are resistant to different levels of streptomycin. A mutant resistant to 700 microg per ml of the antibiotic was found to be made up of two unlinked, independent loci-presumably on different molecules of transforming DNA. These loci, when in separate cells, render them resistant to maximum levels of 10 and 100 microg per ml streptomycin respectively and are therefore designated as Sm(10) and Sm(100). When they enter the same cell they produce a resistance up to 700 microg per ml streptomycin, so the cells are noted as Sm(700). This multiplicative action is more easily visualized as due to two independent processes of combating the antibiotic which enhance each other rather than two identical processes.

Anti-Bacterial Agents↗
PubMed1958

The protein coats or ghosts or coliphage T2. III. Metabolic studies of Escherichia coli B infected with T2 bacteriophage ghosts.

Assimilation of oxygen, inorganic phosphate, and ammonia nitrogen by normal T2 phage and T2 ghost-infected E. coli B was studied. The rate of oxygen and phosphorus uptake by ghost-infected bacteria is similar to that of normal and phage-infected cells. The R.Q. in glucose-salts medium remains approximately 1. Assimilation of ammonia nitrogen by ghost-infected bacteria is maintained at a rate approximately 80 per cent of normal. The inorganic phosphate which is assimilated was found to be incorporated into TCA-soluble compounds which were rapidly released into the medium. Within 5 minutes after absorption of the ghosts there was a loss from the cell of TCA-soluble constituents including organic phosphorus and compounds which absorb at 260 mmicro. No corresponding breakdown of nucleic acid present in the cell prior to infection could be detected. The incorporation of inorganic phosphate into organic linkages in the ghost-infected cell and its release into the medium were found to proceed at a rate approaching that of the incorporation of inorganic phosphorus into the nucleic acid of normal cells. The net increase in 260 mmicro absorbing compounds appeared to be inhibited.

Bacteriophage T4↗
PubMed1958

Photoreactivation in vitro of ultraviolet-inactivated Hemophilus influenzae transforming factor.

Hemophilus influenzae-transforming DNA, which has been inactivated by ultra-violet radiation, is reactivated by visible light in the presence of a cell-free extract of Escherichia coli B. The time rate of reactivation is increased by increasing the E. coli extract concentration, the temperature, and the intensity of illumination. Only DNA containing an ultraviolet-damaged genetic marker exhibits increased transforming activity after treatment with the photoreactivating system. The reactivating capacity of the extract remains in the top supernatant after centrifugation at 110,000 x g for 1 hour and is not present in the pellet. This capacity is destroyed by heating to 90 degrees C. for 1 minute. The active system of the E. coli extract is separable into dialyzable, heat-stable and non-dialyzable, heat-labile fractions. The dialyzable fraction contains at least one component which limits the maximum degree of recovery attained.

Escherichia coli↗
PubMed1957

The protein coats or ghosts of coli phage T2. II. The biological functions.

Phage coats or ghosts, composed entirely of protein, appear to be responsible for protecting the phage nucleic acid from degradation by factors in the surrounding medium; attachment of the virus to its susceptible host; and delivering the nucleic acid to the interior of the cell. In addition, the ghosts have a number of biological actions which resemble similar actions of the parent phage. Thus, they both "kill" cells, inhibit pentosenucleic acid formation, interfere with subsequent infection by other virus particles, block adaptive enzyme formation, induce or trigger lysis of the host, and cause a leakage of phosphorus-containing fragments from the cell. Results to date fail to demonstrate a direct involvement of the ghosts in the passage of genetic information to the progeny. Several of the above changes induced in the host cell following attachment of ghosts could be derived from an alteration in but a single metabolic reaction. The stoichiometry of the ghost-bacterial cell interaction is different from that of the parent phage. Experiments to distinguish between a variable response of the host cell to reaction at different sites and a state of heterogeneity in the ghost preparations suggest the former but they are not decisive.

Bacteriophage T4↗