The Base Composition of Deoxyribonucleic Acids of Streptomyces

Frontali, C.; Hill, L. R.; Silvestri, L. G.

doi:10.1099/00221287-38-2-243

Cited by 27 publications

(9 citation statements)

References 8 publications

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“…These results are also included in Table 3. The buoyant density result for strain 7 confirms very closely the Tm result, whereas the difference of &7y0 GC between values calculated from Tm and from buoyant density for strain 11 is comparable with the systematic differences previously observed (Frontali et al 1965). Both Tm and buoyant density values indicate that these two DNA preparations had unusually low GC contents relative to the three thermophilic actinomycetes and other members of Actinomycetales.…”

Section: Resultssupporting

confidence: 75%

“…Mycelia were collected by centrifugation after 10-15 hr growth of second stage cultures, thus facilitating subsequent lysis (Frontali, Hill & Silvestri, 1965 DNA base ratios of thermophilic actinomycetes 337 Bacteriophage LP7 DNA was used as reference (1.740 g./~m.~). % GC was calculated from p according to the equation: p = 1*660+0.098(GC); (Schildkraut, Marmur & Doty, 1962).…”

Section: Organismsmentioning

confidence: 99%

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Deoxyribonucleic Acid Base Compositions among Thermophilic Actinomycetes: the Occurrence of two Strains with Low GC Content

Craveri¹,

Hill²,

Manachini³

et al. 1965

Journal of General Microbiology

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SUMMARYDeoxyribonucleic acid (DNA) was extracted from two strains of Thermomonospora, two strains of Thermoactinopolyspora and one thermophilic strain of Streptosporangium. Base compositions were determined from ' melting-temperatures ' (Tm) and, in two cases, from buoyant density. DNAs from both Thermoactinopolyspora strains and one Thermomonospora strain were of similar base composition to those previously reported for mesophilic actinomycetes. The other Thermomonospora strain and the Streptosporangium strain, both of which had higher temperature requirements and tolerance for growth, possessed DNA of lower GC content. These findings are discussed in relation to phylogeny, thermophily and the universality of the genetic code.

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Section: Resultssupporting

confidence: 75%

Section: Organismsmentioning

confidence: 99%

Deoxyribonucleic Acid Base Compositions among Thermophilic Actinomycetes: the Occurrence of two Strains with Low GC Content

Craveri¹,

Hill²,

Manachini³

et al. 1965

Journal of General Microbiology

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“…The usual Thermal melting (T,) values for deoxyribonucleic acid (DNA) samples as a measure of the average guanlne plus cytosine ( G + C) content have been determined by many research investigators and used in recent years as an aid in characterizing genetic material. These determinations, along with DNA denaturation studies, have increased information on possible genetic homology of taxonomically related bacteria (1, 2, 3,5,6,10,14,18,19,21,23,25) and have also been used to study the effect of mutation on average DNA base composition (14).…”

Section: Introductionmentioning

confidence: 99%

Use of normal probability paper in determining thermal melting values of deoxyribonucleic acid

Knittel¹,

Black²,

Sandine³

et al. 1968

Can. J. Microbiol.

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A method is described of plotting deoxyribonucleic acid (DNA) thermal melting data which allows informat~on other than average content of guanine plus cytosine to be determined. Absorbancy ( A ) values, corrected for thermal expansion, are plotted on normal probability graph paper and the best straight line drawn. The 50 percentile point on the graph establ~shes the Tm value which allows calculation of the mean base composition. In addition the 2.a (twice the standard deviation) value is easily determined from the probability plot, thus providing information about the degree of variation from the mean in DNA base composition. Comparison of the probability plot and usual graphic methods of determining Tm values provided similar DNA composition data on 15 different strains of Streptococcus lactis, Streptococcus cremoris, and Streptococcus diacetilactis. When many A values obtained from streptococcal DNA samples showing skewed thermal melting curves ( S . lactis b and S. diacetilactis DRC-2) were plotted on normal probability paper, two intersecting straight lines were apparent on the graph. This suggested that there were two types of DNA in these organisms. Each had its own unimodal compositional distribution and its presence was confirmed by density gradient separation. The use of normal probability plots as a rapid method of determining average base composition of DNA samples is suggested. In addition, heterogeneity in base composition may be shown by this method of plotting the data.

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“…A recent study (Frontali et al, 1965) on the base composition of streptomyces DNA expressed as percent guanine plus cytosine shows close Similarity (maximum difference 4%) among the species investigated. It would be interesting to determine whether the sequence of the bases were similar also.…”

Section: Discussionmentioning

confidence: 75%

Streptomyces Genetics and Industrial Microbiology*

Wallo¹

1967

Trans NY Acad Sci

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IntroductionSince the first report of recombination in the streptomyces by Sermonti and Spada-Sermonti (1955), numerous suggestions and criticisms have been offered on the application of genetics to problems in industrial microbiology. Both suggestions and criticisms have been valid in many cases; on the other hand, some have been based on observations made on one o r two streptomyces species and by investigators not always too familiar with problems in industrial microbiology.Admittedly, to date, the applications of genetics to antibiotic production have not been many and the results obtained not overly encouraging. This is particularly evident when the results from programs of induced mutation and selection a r e examined, and it readily becomes apparent that the latter approach is more direct, practical and, a s a rule, successful.With this in mind perhaps, the industrial microbiologist has not placed his greatest effort in applying genetics to his more pressing problems. While frequently an important question, yield improvement is not the only one facing the industrial microbiologist, particularly when the discovery of new useful antibiotic entities is becoming more and more difficult.Other problems, such a s the elimination of unwanted antibiotics when mixtures a r e produced or the alteration of fermentation characteristics in order to modify or eliminate a product, have also been frequently solved by mutation and physiological studies. No attempts appear to have been made a s yet to solve some of these problems by a genetic approach. MethodsPerhaps a brief evaluation of some of the requirements for recombination will make more apparent some of the reasons why genetics has not been applied routinely, or at least more frequently, to industrial microbiological problems. In order to detect whether recombination has occurred, suitably marked strains must be obtained. The markers generally employed a r e nutritional; while this is usually not considered too difficult a matter, it does at times present specialproblems. suitable mutants in this speciesand reporteda number of arginine-dependent auxotrophs. Similarly, in our laboratory, 388 argineless mutants of S . aureofaciens were isolated and only four others with different requirements. The problem in this case was also further aggravated by the almost complete lack of antibiotic-producing ability by these arginine-requiring mutants. While this lack of activity may have some advantage in specific applications, it is disconcerting, to say the least, for the investigator who is trying to improve yields to have to start from a zero level of activity.Usually, however, mutants with a single requirement a r e obtained with relative ease as a r e doubly auxotrophic mutants without hampering the viability of the culture. At the same time, the antibiotic-producing ability of the mutant may or may not be decreased with each nutritional impairment.While time consuming, these a r e still not major problems. The final test comes when a series of auxotrophic mutants is mated...

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The Base Composition of Deoxyribonucleic Acids of Streptomyces

Cited by 27 publications

References 8 publications

Deoxyribonucleic Acid Base Compositions among Thermophilic Actinomycetes: the Occurrence of two Strains with Low GC Content

Deoxyribonucleic Acid Base Compositions among Thermophilic Actinomycetes: the Occurrence of two Strains with Low GC Content

Use of normal probability paper in determining thermal melting values of deoxyribonucleic acid

Streptomyces Genetics and Industrial Microbiology*

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