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PubMed1971

Characteristics of a bacteriocin derived from Streptococcus faecalis var. zymogenes antagonistic to Diplococcus peumoniae.

A bacteriocin-producing strain of Streptococcus faecalis var. zymogenes (E-1) was isolated from clinical material (conjunctiva). The active substance differed from bacteriocins described by other investigators primarily in its spectrum of antibacterial activity, especially by its marked inhibition of Diplococcus pneumoniae. The E-1 bacteriocin also inhibited nonhemolytic strains of enterococci as well as one-third of the Viridans group of streptococcal strains investigated. The degree of inhibition, however, as indicated by the size of the zones against the latter organisms, was significantly reduced. No activity was detected against any of the strains belonging to the following groups of bacteria: hemolytic enterococci, beta-hemolytic streptococci, nonhemolytic streptococci, staphylococci, and various gram-negative species. Similarly, three strains each of Bacillus cereus and Listeria monocytogenes and one strain of Erysipelothrix insidiosa were not inhibited. The bacteriocin was able to diffuse through bacterial membranes as well as cellulose dialyzer tubing. It was inactivated by heating to 80 C for 20 min but resisted inactivation by either trypsin or chloroform.

Agar↗
PubMed1974

Amino acid flux and protein synthesis after exposure of rats to either Diplococcus pneumoniae or Salmonella typhimurium.

At 26 h after inoculation of rats with Diplococcus pneumoniae, the serum concentrations of 10 and 20 individual amino acids were lower than corresponding values observed in pair-fed controls. In contrast, only 2 of 20 serum amino acids were similarly decreased in rats inoculated with Salmonella typhimurium. Despite these serum differences, a greater accumulation of labeled non-metabolizable amino acids occurred in the livers of rats infected with S. typhimurium. These data suggested a greater increase in the flux of amino acids from muscle to liver in the rats infected with S. typhimurium as compared to those infected with D. pneumoniae. A similar increase in serum protein synthesis was observed in rats infected with D. pneumoniae or S. typhimurium. However, with the latter infection, a larger percentage of the amino acids appeared to be utilized as a source of energy in addition to their role as precursors of proteins.

Amino Acids↗
PubMed1974

Persistence of Diplococcus pneumoniae after influenza virus infection in Macaca mulatta.

Exposure of monkeys to aerosols of influenza virus followed later by aerosols of Diplococcus pneumoniae resulted in persistence of the bacteria in the upper respiratory tract for an average of 28 days. Examination of selected tissues for pneumococci revealed that pneumococci were widely disseminated throughout the respiratory tract at 3 and 7 days after exposure, but were cleared from lower respiratory tissues and were found mainly in tonsils, oropharynx, and posterior nasopharynx after 14 days.

Aerosols↗
PubMed1974

Vitamin E protects mice against Diplococcus pneumoniae type I infection.

Vitamin E protects nonimmunized and immunized mice against fatal Diplococcus pneumoniae type I (DpI) infection. A dietary supplementation of 180 mg of dl-alpha-tocopheryl acetate per kg of diet increased survival of nonimmunized mice from 20 to 80% when challenged with 20 organisms, and of mice immunized with 0.5 ng of DpI polysaccharide from 15 to 70% when challenged with 20,000 organisms. The phagocytic index of immunized mice was four times higher in the 180-mg vitamin E group than in the control group. Both the survival and phagocytic index revealed a biphasic dose response, indicating a cause-effect relationship between phagocytosis and survival. Vitamin E also significantly increased the rate of carbon clearance from blood, indicating a general increase in phagocytic activity. The data indicated that increased macrophage activity probably aided by increased antibody production was the principal reason for increased protection.

Animals↗
PubMed1971

Tissue amino acid flux after exposure of rats to Diplococcus pneumoniae.

The concentration of 21 individual free amino acids in serum, liver, and skeletal muscle was determined in rats during the incubation, acute illness, and terminal stages of experimental infection with Diplococcus pneumoniae. By 4 hr after subcutaneous inoculation with bacteria, the concentration of total and many individual free amino acids in serum, liver, and muscle was significantly decreased in comparison to findings in noninfected, pair-fed control rats. By use of a nonmetabolizable amino acid analogue (cycloleucine), it was possible to detect a flux of amino acids from muscle to liver in the infected rat. The endogenous amino acids which moved to the liver were rapidly utilized for the synthesis of serum proteins.

Amino Acids↗
PubMed1972

Enteric bacteria cross-reactive with Neisseria meningitidis groups A and C and Diplococcus pneumoniae types I and 3.

Enteric bacteria of 1,335 individual strains were studied for serological cross-reactions with Neisseria meningitidis groups A and C and Diplococcus pneumoniae types I and III. Enterobacterial antigens cross-reactive with the capsular polysaccharides of these four bacteria were found. Bacteria cross-reactive with noncapsular antigens of meningococci and pneumococci were also observed. Since some enteric bacteria possess antigens with serological specificities similar to those of meningococci, the possibility that enteric bacteria cross-reactive with meningococcal antigens provide an antigenic stimulus for the observed age-related "natural" immunity to this pathogen is discussed.

Animals↗
PubMed1970

Competent Diplococcus pneumoniae accept both single- and double-stranded deoxyribonucleic acid.

The transforming activity of fractionated complementary strands of Diplococcus pneumoniae deoxyribonucleic acid (DNA) bands at the position of fully denatured DNA in CsCl at pH 11.0, and is completely (> 99.8%) destroyed by digestion with exonuclease-I. These results prove that pure single strands transform the normally prepared competent cells of this species. Their efficiency is about 0.5% that of native DNA of comparable size.

Cesium↗
PubMed1970

Mutants of Diplococcus pneumoniae that lack deoxyribonucleases and other activities possibly pertinent to genetic transformation.

Mutants of Diplococcus pneumoniae that lacked the two major deoxyribonucleases of the cell-one an endonuclease, the other an exonuclease preferentially active on native deoxyribonucleic acid (DNA)-were obtained. The development of a method for detecting mutant colonies, based on the binding of methyl green to DNA, facilitated isolation of the mutants. Neither enzyme was essential for growth of the cells, for repair of ultraviolet damage, or for any phase of DNA-mediated transformation. Residual deoxyribonuclease activity in the double mutant corresponded to an exonuclease, approximately one-fifth as active as the major exonuclease, that attacked native and denatured DNA equally well. This activity appeared to be associated with the DNA-polymerase enzyme. A mutant that apparently lacked a cell wall lytic enzyme was also fully transformable. A mutant strain that was four times more sensitive to ultraviolet light than the wild type also transformed normally. Recipient cells of this strain were deficient in the repair of ultraviolet-irradiated transforming DNA. Mutants were found which, unlike the wild type, integrated donor markers only with high efficiency, thereby indicating that a particular cellular component that is susceptible to loss by mutation, such as an enzyme, is responsible for low integration efficiency.

Cell Wall↗
PubMed1971

High dihydrofolate reductase levels in Diplococcus pneumoniae after mutation in the structural gene: biochemical and immunological evidence for increased synthesis.

A unique class of missense mutations in the dihydrofolate reductase structural gene of Diplococcus pneumoniae determines marked increases in the corresponding enzyme activity. Immunological evidence, based on precipitating and neutralizing antibody reactions, is presented in support of previously derived findings which attribute this increase in activity to an increase in the amount of enzyme protein. Biochemical evidence was obtained which shows that the increased amounts of dihydrofolate reductase protein in the mutants not owing to a decrease in degradation, reducing turnover, or to an increase in stability, and, therefore, probably related to an increase in the rate of synthesis of new protein. The manner in which a missense alteration of a structural gene might quantitatively alter the expression of that gene is discussed.

Animals↗
PubMed1972

Events occurring near the time of synapsis during transformation in Diplococcus pneumoniae.

A marker-specific and strongly temperature-dependent reaction was observed to occur at a time during transformation in Diplococcus pneumoniae after the donor deoxyribonucleic acid (DNA) had acquired single-strand properties and immediately preceding the integration of these strands into the recipient chromosome. Operationally, it was observed as the prevention of an intracellular inactivation process, also described in this paper, which is specific for low molecular weight or for damaged DNA, and which occurs if the recipient cells are held at suboptimal temperatures after the DNA has entered. Brief exposure of the cells to a higher temperature stabilized the DNA against this inactivation, in a two step process. It is the first step which has a strong temperature dependence (DeltaHdouble dagger = 70 kcal/mole, DeltaSdouble dagger = 160 entropy units), is marker specific, and which appears to be reversible. The second step is much less temperature-dependent and overlaps in time the start of integration. The enthalpy and entropy of activation are both consistent with those needed to open a loop of six to eight base pairs in a DNA duplex. It is suggested that these observations may reflect, and provide an assay for, the kinetics of synapsis, which on this model is limited in rate by the appearance of unpaired regions on the recipient duplex.

Chromosomes, Bacterial↗
PubMed1973

Competence for deoxyribonucleic acid uptake and deoxyribonuclease action external to cells in the genetic transformation of Diplococcus pneumoniae.

A mutant of Diplococcus pneumoniae that apparently does not require activator can become competent for uptake of deoxyribonucleic acid (DNA) when grown in dilute cultures or in the presence of trypsin. Development of competence in both mutant and wild strains is temperature dependent, being 10-fold greater at 30 C than at 37 C. Induction of competence on a shift from 37 to 30 C requires protein synthesis and the presence of Mg(2+) and Ca(2+); uptake of DNA does not require protein synthesis. Competence decays exponentially at higher temperatures. As well as taking up DNA, competent cells release oligonucleotide fragments of donor DNA in the medium external to the cells. Normal strains release fragments comparable in amount to the DNA taken up; but, in a mutant selected for inability to degrade DNA in agar, the amount of fragments formed external to the cells is only 40% of DNA uptake. Requirements for external deoxyribonuclease action are identical to those for DNA uptake: prior development of competence and the presence during treatment with DNA of Mg(2+) ions and a source of energy.

Calcium↗
PubMed1974

Specificity of the autolysin of Streptococcus (Diplococcus) pneumoniae.

A Streptococcus (Diplococcus) pneumoniae autolysin, partially purified from cellular autolysates, was optimally active at pH 7.0 and was stimulated by monovalent cations. Addition of autolysin to walls resulted in the appearance of only N-terminal l-alanine, whereas no glycosidase activity was observed. Walls which had been solubilized by autolysin were separated by gel filtration into a low-molecular-weight peptide containing amino acids in the same ratios found in intact walls and a high molecular fraction containing the amino acid-deficient peptidoglycan backbone. Thus, the major activity is an N-acetylmuramyl-l-alanine amidase. In addition, walls undergoing spontaneous lysis revealed no glycosidase activity but showed an increase in only N-terminal alanine. Autolysin, which was bound to walls in saline, was almost completely removed when walls were washed in distilled water, and all of the activity was recovered in the water wash fluid.

Alanine↗
PubMed1975

Identification of a deoxyribonuclease implicated in genetic transformation of Diplococcus pneumoniae.

A mutation of Diplococcus pneumoniae, end-1, reduces the major deoxyribonuclease activity of the cell, an endonuclease, to 10% of its normal value without impairing transformation. Further mutations, called noz, abolish the residual endonuclease activity and block transformation. The residual endonuclease is similar to the wild-type enzyme in size, charge, divalent cation dependence, inhibition by ribonucleic acid, and formation of oligonucleotide products. However, the mutant endonuclease is more temperature sensitive, which suggests that the end-1 mutation occurred in a structural gene for the enzyme. Genetic analysis showed that the noz mutations occur at the same genetic locus. A number of new end mutants were analyzed. Those that retained more than 1.4% of the normal endonuclease activity were essentially normal in transformation; those with less than 1% were defective. The transformation-defective end mutants appear to be blocked in the entry of deoxyribonucleic acid (DNA) since they carry out the prior step of binding DNA to the outside of the cell. The major endonuclease of the cell may act as a DNA translocase by attacking and degrading one strand of DNA, thereby facilitating entry of the complementary strand into the cell.

Cations, Divalent↗
PubMed1975

Membrane location of a deoxyribonuclease implicated in the genetic transformation of Diplococcus pneumoniae.

The cellular localization of enzymes in Diplococcus pneumoniae was examined by fractionation of spheroplasts. A deoxyribonuclease implicated in the entry of deoxyribonucleic acid (DNA) into the cell during genetic transformation was located in the cell membrane. This enzyme, the major endonuclease of the cell (endonuclease I), which is necessary for the conversion of donor DNA to single strands inside the cell and oligonucleotides outside, thus could act at the cell surface. Another enzyme, the cell wall lysin (autolysin), was also found in the membrane fraction. Other enzymes, including amylomaltase, two exonucleases, and adenosine triphosphate-dependent deoxyribonuclease, and a restriction type endonuclease, were located in the cytosol within the cell. None of the enzymes examined were predominantly periplasmic in location. Spheroplasts were obtained spontaneously on incubation of pneumococcal cells in concentrated sugar solutions. The autolytic enzyme appears to be involved in this process. Cells that were physiologically competent to take up DNA formed osmotically sensitive spheroplasts two to three times faster than cells that were not in the competent state. Although some genetically incompetent mutants also formed spheroplasts more slowly, other such mutants formed them at the faster rate.

Cell Fractionation↗
PubMed1976

Size and transforming activity of deoxyribonucleic acid in Diplococcus pneumoniae during thymidine starvation.

The transforming activity and the molecular structure of DNA from cells of Diplococcus pneumoniae during thymidine starvation have been analyzed and the effects of thymidine starvation have been compared with the effects of single-strand breaks produced by deoxyribonucleases in DNA of unstarved cells. The decrease in transforming activity of lysates from starved cells as a function of the size of DNA particles, measured by centrifugation in neutral and alkaline sucrose gradients, does not follow the kinetics observed after enzymatic degradation of DNA of unstarved cells. Moreover, a strain lacking exo- and endonuclease activities is not protected from thymineless death. These results suggest that the basic lethal mechanism of thymidine starvation might have an origin other than the activation of nucleases.

Centrifugation, Density Gradient↗
PubMed1961

Antigenic structure and serological relationships of Mycobacterium, Actinomyces, Streptococcus, and Diplococcus.

Kwapinski, Jerzy B. (South African Institute for Medical Research, Johannesburg), and Marshall L. Snyder. Antigenic structure and serological relationships of Mycobacterium, Actinomyces, Streptococcus, and Diplococcus. J. Bacteriol. 82:632-639. 1961.-Chemical fractions, 72 in all, from four strains of Mycobacterium, four strains of Actinomyces, and four strains of Streptococceae, were tested in homologous and heterologous antisera prepared against intact cells and chemical fractions of Mycobacterium tuberculosis. Antigens isolated from the cytoplasm of these bacteria proved to be serologically related to each other. In contrast, most of the cell-wall antigens, except those extracted with either 30% sodium hydroxide or formamide at 100 to 130 C, were species specific. Sera prepared against the individual fractions of Mycobacterium reacted only with the strain of Mycobacterium from which they were isolated.

Actinomyces↗
PubMed1967

Genetically alterable transport of amethopterin in Diplococcus pneumoniae. I. Physiological properties and kinetics of the wild-type system.

A system of H(3)-amethopterin uptake, physiologically and kinetically resembling active transport, has been described in Diplococcus pneumoniae. Uptake by this system has a pH optimum near 6.0, is temperature-dependent, requires a readily available source of energy, and conforms to Michaelis-Menten kinetics. The system showed a K(m) of 0.9 x 10(-6)m and a V(max) of 1.9 x 10(-13) moles per min per mg (dry weight). Both folate and H(2)-folate compete with H(3)-amethopterin for the same system, but to a limited degree. The intracellular concentration of H(3)-amethopterin accumulated at equilibrium was 1.06 x 10(-9) moles/ml or fivefold the external concentration when the latter was limiting, but at least 60-fold the internal concentration attained solely by diffusion in the same time interval at 0 C.

Glucose↗