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S H Goodgal

Publications and source records attributed to S H Goodgal.

At least 37 records · Page 2Linked to original sources
PubMed1977

A technique for the rapid selection of drug-sensitive and auxotrophic mutants of Phycomyces blakesleeanus.

An auxotroph enrichment procedure has been developed for Phycomyces blakesleeanus which has proven useful in obtaining both auxotrophs and drug-sensitive mutants. The technique is based on the differential heat sensitivity between ungerminated auxotrophic spores and germinated prototrophic spores. Germinated spores and mycelia die when left at temperatures higher than about 35 degrees C for 16 to 24 h but ungerminated spores survive this treatment and subsequently germinate if transferred to complete medium. With the dwarf colonial strain, replica plating permits the rapid characterization of these newly selected auxotrophs.

Drug Resistance, Microbial↗
PubMed1976

Biological properties of a Haemophilus influenzae restriction enzyme, Hind I.

A type I restriction enzyme from Haemophilus influenzae, Hind I, which requires adenosine 5' -triphosphate and 5-adenosyl methionine, was studied for its activity on transfecting and transforming deoxyribonculeic acid (DNA). The enzyme reduced the size of unmodified bacteriophage S2 DNA from 37 X 10(6) daltons to approximately 10 X 10(6) daltons, but did not affect modified S2 DNA. Unmodified transforming DNA was attacked in vitro by Hind I; however, relatively low levels of inactivation were obtained for single markers, and linked transformants were inactivated as a function of the distance between markers. In contrast, unmodified bacterial DNA was not inactivated in vivo for either single or linked markers by the Hind I restriction system, probably because the segments generated by Hind I were still capable of being integrated in vivo. The lack of preferential inactivation of markers by the enzyme suggests that it makes random breaks in the DNA.

Adenosine Triphosphate↗
PubMed1973

Separation of specific segments of transforming DNA after treatment with endodeoxyribonuclease.

Hemophilus parainfluenzae endodeoxyribonuclease was used to degrade the DNA of H. influenzae and to follow the biological activity of 14 markers associated with this DNA. It was found that some H. influenzae markers were completely inactivated by endodeoxyribonuclease treatment, while others appeared to retain all or almost all of their original activity. The bulk of the H. influenzae DNA was reduced to double-stranded pieces of the order of 8 x 10(5) to 1 x 10(6) daltons. Velocity sedimentation of the DNA in sucrose gradients disclosed that markers that retained biological activity were present in DNA particles that were of the order of 1 x 10(6) daltons or larger, and indicated a close correlation between the size of the DNA fragment and the amount of biological activity retained. These data suggest that H. parainfluenzae endodeoxyribonuclease breaks DNA at specific sites. The nal(r) marker was shown to have twice as much biological activity after treatment with endodeoxyribonuclease when assayed at saturating DNA concentrations. In the linear portion of the DNA dose-response curve, the biological activity of this marker was reduced 3- to 10-fold compared to untreated DNA (in accord with the reduced size of its DNA). These data demonstrate a specific enrichment of the nal(r) marker by about 6- to 20-fold, and suggest a technique for the separation and purification of specific segments of DNA.

Bacillus subtilis↗
PubMed1972

Competence mutants. II. Physical and biological fate of donor transforming deoxyribonucleic acid.

Transformation-deficient (com(-)) mutants, which are able to bind donor transforming deoxyribonucleic acid (DNA) without yielding a significant number of transformants, were studied with regard to the fate of donor DNA. In no case was there any detectable degradation into acid-soluble radioactivity after donor DNA uptake. Physical experiments showed that some of these mutants are deficient in their ability to associate donor DNA with the recipient's chromosome (dad(-) mutants, for donor association defective), whereas others are able to form what appear to be normal donor-recipient complexes. In spite of physical evidence for integration, none of the dad(-) mutants contains biologically active recombinant DNA, suggesting that they might be deficient in the recombination process (dab(-) mutants, for donor association biologically defective). Donor biological activity is not replicated in any of the mutant strains, and in some cases there is a 10-fold reduction of donor transforming DNA within 60 min after DNA uptake.

Bacteriological Techniques↗
PubMed1972

Competence mutants. 3. Responses to radiations.

Class 3 com(-) mutants [normal in deoxyribonucleic acid (DNA) uptake but poor in ability to transform] were investigated with regard to ultraviolet (UV) and X-ray sensitivity of colony-forming ability and with regard to their ability to be transformed by UV- and X-ray-irradiated DNA. Three mutants, com(-)40, 60, and 78, were highly UV-sensitive in colony-forming ability. None of the mutants was more sensitive than wild type to UV-irradiated transforming DNA; in fact, six of the mutants showed considerably greater resistance. Two of the mutants (com(-)40 and 60) were slightly more sensitive to X ray in colony formation, whereas most of the mutants showed some degree of sensitivity to X-ray-irradiated transforming DNA. In addition, the physical fate of X-ray-irradiated transforming DNA has been examined, and in one case (com(-)48) there was a significant drop in sedimentation value of X-ray-irradiated donor DNA after uptake by recipient cells. The com(-) mutants analyzed have been classified on the basis of their UV and X-ray sensitivities, and, where appropriate, possible biochemical lesions have been implicated.

Bacteriological Techniques↗
PubMed1972

Action of haemophilus endodeoxyribonuclease on biologically active deoxyribonucleic acid.

An enzyme similar to that described by Smith and Wilcox (15) for Haemophilus influenzae which attacks foreign deoxyribonucleic acid (DNA) but not its own has been isolated and purified from H. parainfluenzae. The enzyme degrades foreign DNA to limited sizes and can destroy the transforming activity of H. influenzae and Bacillus subtilis DNA. The enzyme can also destroy the biological activity of H. influenzae phage and prophage DNA. On the other hand, the H. influenzae endodeoxyribonuclease can destroy the transforming activity of H. parainfluenzae DNA but not its own DNA. It also attacks B. subtilis DNA and its transforming activity.

Ammonium Sulfate↗
PubMed1972

Competence Mutant of Haemophilus influenzae with Abnormal Ratios of Marker Efficiencies in Transformation.

In studies of competence-deficient mutants of Haemophilus influenzae which absorb deoxyribonucleic acid (DNA) but fail to produce transformants, it was observed that in some mutants the residual transforming activity for different markers varied widely, i.e., produced a ratio effect. One of these mutants, com(-56), was studied intensively to determine the cause of the residual efficiency of transformation and the reason for the ratio effect. The residual frequency of transformation was higher for markers considered single-site mutations (like naladixic acid resistance), whereas the least efficient markers tested were those conferring resistance to high levels of streptomycin or novobiocin which are more complex than single-site mutations. Measurement of frequencies of cotransformation indicated that overall genetic linkage was reduced. Transfection was fairly efficient with phage S2 DNA, but not prophage DNA. Donor marker activity could be detected in transformed cell lysates, but not linked to recipient markers in recombinant molecules. Sucrose gradient analysis of such lysates revealed that donor material was associated with recipient DNA in at least normal quantities, but lacked detectable genetic activity. Material from donor DNA labeled with heavy isotopes was incorporated into recipient chromosomal fragments having a density indistinguishable from normal density, unlike the hybrid density recombinant material found in normal cells. No excessive solubilization or nicking of unincorporated donor was detected. It is postulated that this strain contains a hyperactive nuclease, which reduces the effective size of the input DNA during the integration process.

Journal Article↗
PubMed1968

Prophage S2 mutants in Haemophilus influenzae: a technique for their production and isolation.

A procedure utilizing nitrosoguanidine has been developed to produce defective and temperature-sensitive mutants of prophage (S2) in lysogenic Haemophilus influenzae. The system should be generally applicable to all temperate phage systems. At saturating concentrations of phage DNA, more than 25 percent of recipient mutant lysogenic bacteria can be transformed to the wild type.

Bacteriophages↗