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M R KRAUSS

Publications and source records attributed to M R KRAUSS.

6 recordsLinked to original sources
PubMed1963

INTRASPECIES AND INTERSPECIES TRANSFORMATION REACTIONS IN PNEUMOCOCCUS AND STREPTOCOCCUS.

The efficiency of transformation of pneumococcus and a strain of viridans streptococcus (strain D) to streptomycin resistance is influenced by the species in which the mutation to resistance occurred, as well as by the species in which the mutated gene has been replicated. Pneumococcus and streptococcus strain D transform in higher frequency with DNA that has been replicated in bacteria of the same species than with DNA from the heterologous species. However, the difference between the frequencies of interspecific and intraspecific transformation is much greater with pneumococcus as receptor than with streptococcus. In addition pneumococcus transforms in higher frequency with wholly homologous (pneumococcal) DNA than with DNA from pneumococci that have replicated the streptococcal Sm(r) gene. Pneumococcus is transformed in lower frequency by wholly heterologous (streptococcal) DNA than by DNA from streptococci that have replicated the pneumococcal Sm(r) gene. Streptococcus behaves similarly in that wholly homologous (streptococcal) DNA transforms it more efficiently than when the transforming fragment contains a pneumococcal moiety. Streptococcus is transformed in the same or lower frequency by wholly heterologous (pneumococcal) DNA than by DNA from pneumococci that have replicated the streptococcal Sm(r) gene. When erythromycin resistance was used as genetic marker instead of streptomycin resistance, similar results were found.

DNA↗
PubMed1959

Determination of type in capsulated transformants on pneumococcus by the genome of non-capsulated donor and recipient strains.

Capsulated transformants producing type II polysaccharide have been obtained by reactions between a number of R mutants of type II pneumococcus. All the IIR strains except II-R36 yielded extracts which transformed 2 VIIIR strains to VIIIS. Two of the IIR strains were transformed to VIIIS by an extract of 1 VIIIR strain. The most striking result was the production of both IIS and VIIIS transformants by the action of extracts of both VIIIR strains applied to cells of II-RB. This suggests that the determination of capsular type in pneumococcus does not depend on single allelomorphic genes; it seems more likely that a number of genes may be required to determine type specificity, and that some genes may be common to different types, possibly in connection with common biochemical pathways for some stages of polysaccharide synthesis. This is further indicated by the finding that extracts of capsulated strains of each of the types I, II, III, VII, VIII, XIV, and XVIII are capable of giving IIS transformants with 1 or more of the IIR strains in addition to the expected donor-type transformants. Strain II-R36 was transformed by extracts of all S types except type VII, but the only transformants found were of the donor type. It appears that II-R36 may have multiple genetic deficiencies for type II capsulation, possibly in the form of a deletion. This may be the case also with IIIS strains since only IIIS transformants were found when IIIS extract was applied to any of the IIR strains.

Polysaccharides↗
PubMed1957

Transformation reactions between Pneumococcus and three strains of Streptococci.

Reciprocal transformation reactions to streptomycin resistance have been demonstrated between pneumococcus and 2 strains of viridans streptococci, which by the usual bacteriological criteria are distantly related to pneumococcus. Desoxyribonucleic acid (DNA) extracts of a strain of streptomycin-resistant Streptococcus salivarius have been found capable of transforming pneumococcus and two strains of viridans streptococci but the strain itself was not transformed by autologous or heterologous DNA extracts. The two strains of viridans streptococci were more efficient than pneumococcus as receptors of both autologous and heterologous transforming principles. It is inferred, therefore, that efficiency of transformation does not necessarily indicate closeness of relationship among bacteria. The efficiency of transforming principles (TP's) from three streptococcal strains to induce streptomycin resistance in pneumococcus increased following their reduplication in pneumococcus. At the same time the efficiency of two of these TP's to transform streptococcus was reduced. Resistance to optochin (ethylhydrocupreine), a characteristic of most streptococci, can be transferred to pneumococcus, a naturally susceptible species, by transformation reactions.

Carrier Proteins↗
PubMed1956

Transformation reactions with two non-allelic R mutants of the same strain of Pneumococcus type VIII.

Two distinct R mutants of pneumococcus type VIIIS have been described in which the mutations leading to loss of type VIII polysaccharide production are non-allelic. A DNA extract prepared from either R strain restores the capacity to produce type VIII polysaccharide in the other strain. Autologous extracts are inert in this respect. DNA extracts from pneumococcus type IIS when applied to the two R mutants consistently yielded a high proportion of cells transformed to type VIIIS and relatively small numbers of type IIS cells. When extracts prepared from other encapsulated pneumococci, types IS, VIIS, XIVS, and XVIIIS, were applied to R mutant VIII-R1, a mixture of type VIIIS cells and cells corresponding to the type of the donor appeared, although the proportion of type VIIIS cells was not uniformly in excess. The same extracts applied to the second R mutant, VIII-R13, yielded transformed cells of the type of the donor only, or else transformation did not occur. Transforming extracts of a strain of pneumococcus type IIIS gave rise only to type IIIS pneumococci when applied to either strain. Type VIIIS pneumococci were never recovered from such interactions.

Mutation↗