Inhibition of phage multiplication by nitrofuryl-vinyl-quinoline derivatives.
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Antiviral Agents↗
Biomedical subjects
A Taketo
Publications and source records attributed to A Taketo.
Inducibility of lambda phage development in Escherichia coli mutants thermosensitive for DNA replication.
In a thermosensitive dnaZ mutant lysogenic for lambda, induction of the prophage development was provoked at the restrictive temperature. In dnaD strain, spontaneous release of lambda proceeded even at 43 degrees C, but distinct induction of the prophage development was not caused by a heat treatment. Similarly, shift up of growth temperature did not lead to induction of lambda in lysogens carrying thermosensitive mutation in dnaH function or DNA polymerase I. In dnaH mutant, multiplication of lambda-virulent phage proceeded normally at 43 degrees C.
Coliphages↗
Sensitivity of Escherichia coli to viral nucleic acid, X. Ba2+-induced competence for transfecting DNA.
Effect of alkaline earth metal ions on induction of the competence for DNA transfection was investigated. Unlike spheroplasts, the bulk of the bacteria treated with these ions retains colony-forming ability. The order of effectiveness for transfection of phiA replicative-form DNA has been found to be Ba2+ greater than Ca2+ greater than Sr2+ greater than Mg2+. The competence of Ba2+-treated cells is 3 to 5 times higher that that of Ca2+-treated bacteria and about 40 times higher than that of lysozyme-EDTA spheroplasts. The Ba2+-dependent transfection is cryophilic and formation of the infective complex occurs very rapidly at 0 degrees C, But not at 37 degrees C.
Barium↗
Sensitivity of Escherichia coli to viral nucleic acid, XII. Ca2+- or Ba2+-facilitated transfection of cell envelope mutants.
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Bacterial Proteins↗
Effects of polynucleotides on production and activity of streptolysin S.
Activity of various natural and synthetic polynucleotides as a carrier for streptolysin S was tested in a resting cell system. As the carrier, intact molecules of MS2 RNA, E coli tRNA or rat liver RNA were almost inactive, whereas RNase I core of these RNAs, especially the core fractions eluted from DEAE-cellulose column at higher NaCl concentrations, effectively induced production of the extracellular hemolysin. The carrier activity of yeast RNA was significantly enhanced by simultaneous addition of RNase I, to the streptococcal suspension. Preincubation of yeast RNA with growing streptococci or a protein fraction from the bacterial culture supernatant increased its carrier activity. Evidences were obtained suggesting involvement of streptococcal nuclease in the enhancement of the carrier effect. Production of the streptococcal hemolysin was markedly promoted by polyguanylic acid but neither by polyadenylic acid, polycytidylic acid nor by polyuridylic acid. Like trypan blue, polyguanylic acid exerted potent inhibitory effect on hemolytic activity of streptolysin S complex. Similar but less marked effect was observed with certain RNase I core fractions of rat liver RNA. Some data concerning effect of polynucleotides on stability of the hemolysin were also presented.
Animals↗
Sensitivity of Escherichia coli to viral nucleic acid. XVI. Temperature conditions for Ca2+-dependent dna uptake in Escherichia coli.
Properties of Ca2+- or Ba2+-dependent transfection and transformation in Escherichia coli were examined, using phi X174 replicative-form (RF) DNA and plasmid DNA. For the transfection and transformation, a heat pulse step was dispensable and the yield of transfectants was, in most E. coli strains, rather reduced by the heat treatment. The heat pulse step was also detrimental for the transformation of certain strains such as lipopolysaccharide mutants, The first stage of the DNA uptake process (formation of DNA . recipient cell complex) was dependent on low temperature and Ca2+ ion. A substantial amount of the complexed RF-DNA was released from the bacteria, by washing with a chilled Tris buffer. Although a RF-DNA . cell complex was formed even at 37 degree C or in chilled 0.05 m MgC12, the complex did not yield transfectants.
Bacteriophage phi X 174↗
Effects of trypan blue and related compounds on production and activity of streptolysin S.
Most dyes related to trypan blue inhibited hemolytic activity of oligonucleotide-streptolysin S (SLS) complex, an exotoxin produced by Streptococcus pyogenes. Order of the inhibition was: trypan blue greater than benzo blue 2B greater than Congo red greater than Evans blue greater than benzo purpurine 4B greater than thiazine red greater than trypan red. When resting streptococcal cells were incubated with these dyes, significant amount of the hemolysin was produced. The carrier (or inducing) activity for SLS was further manifested in growing cell system and the potency of the compounds was as follows: Congo red greater than benzo blue 2B greater than trypan blue greater than Evans blue greater than Benzo purpurine 4B greater than or equal to thiazine red greater than trypan red. In this system, Congo red was more effective than oligonucleotide fraction rich in guanyl residue. Chromotrope 2B, H acid and o-tolidine were ineffective, as the carrier as well as the inhibitor. Based on these results, structure-function relationship among SLS, the carrier and the inhibitor was discussed.
Animals↗
Effect of streptococcal extracellular nuclease on the carrier activity of RNA for streptolysin S.
Upon digestion with a streptococcal extracellular nuclease, yeast RNA yielded acid-insoluble core having increased carrier activity for streptolysin S. The carrier activity was found in minor fractions of the core which were eluted from a DEAE-cellulose column at higher salt concentrations. Upon gel filtration through a Sephadex G-75 column, the effective component (Fr. I) was eluted earlier than bulk oligonucleotides (Fr. II). Nucleotide composition (in mol %) of Fr. I was AMP: 21.8; GMP: 55.1; CMP: 8.2; UMP: 14.9, whereas that of Fr. II was AMP: 38.0; GMP: 33.1; CMP: 8.0; UMP: 20.9. Chromatographic patterns of SLS complex induced by Fr. I were similar to those of the toxin formed in the presence of active fraction prepared from RNase I core. Hemolytic activity of the latter complex was, like the former, unaffected by streptococcal nuclease treatment. The carrier activity of DNA digested with the nuclease was also investigated.
Animals↗
Effects of membrane-acting drugs and aerobiosis on production of streptolysin S and nuclease in hemolytic streptococci.
Yield of streptolysin S (SLS) in streptococcal culture was considerably reduced by procaine, dibucaine, atropine or chlorpromazine at concentrations which scarcely affected production of an extracellular nuclease as well as the bacterial growth. Cerulenin was also inhibitory to SLS formation, but its effect was more pronounced on the nuclease production. By aerobiosis, amount of SLS produced into culture supernatant was increased significantly, whereas yield of the nuclease was rather unaffected.
Aerobiosis↗
Enhanced production of cell-bound and extracellular streptolysin S by hemolytic streptococci pretreated with proteases.
The amount of streptolysin S produced by resting streptococci was considerably increased after incubation of the washed bacteria with trypsin or pronase. Production of both cell-bound and free forms of the toxin was enhanced by the protease treatment. By addition of trypsin, streptolysin S yield was considerably increased in growing culture as well. Treatment with lysozyme was ineffective, and the toxin production was only slightly promoted by preincubation with hyaluronidase or chymotrypsin. In contrast, pretreatment with chymotrypsin caused increased production of an extracellular nuclease, whereas the yield of this enzyme was reduced after incubation of the cocci with pronase. Evidence was obtained indicating de novo synthesis of the exotoxin in the protease-treated bacteria.
Anti-Bacterial Agents↗
Effects of norfloxacin and rifampicin on growth and streptolysin S production in hemolytic streptococci.
Norfloxacin, a nalidixic acid analogue, inhibited streptolysin S (SLS) production when added to young streptococcal culture. DNA synthesis was mainly affected, but increment of cell mass, RNA and protein was also significantly reduced in streptococci treated with norfloxacin. In stationary phase cells and in the washed resting bacteria, the toxin production was resistant to the drug. Pretreatment with norfloxacin did not abolish the cellular capacity to produce SLS. Although extracellular SLS was detectable at log phase of streptococcal growth, enhanced production of the toxin occurred upon cessation of coccal multiplication. In contrast to norfloxacin, lower concentration of rifampicin inhibited SLS production, even added at late log or early stationary phase. Roles of growth phase, medium and carrier in induction of SLS production were analyzed as well.
Bacterial Proteins↗
Differentiation-inducing effect of thymidine on human neuroblastoma cells.
Human neuroblastoma cells (KP-N-RT(BMI) treated with thymidine underwent morphological differentiation, as revealed by the extension of neurites. The morphological differentiation was caused by deoxyadenosine as well, but not by thymine or deoxyribose. The neurite-extending effect of thymidine was counteracted by deoxycytidine, indicating that inhibition of ribonucleotide reductase was involved. Similar morphological change was indeed brought about by hydroxyurea, a specific inhibitor of the enzyme. Azidothymidine and dideoxythymidine were also effective in induction of neurite extension, suggesting that inhibition of DNA replication, rather than the reductase per se, is responsible for the induction of neurite extension. Supporting this notion, various inhibitors of DNA synthesis induced the morphological differentiation of the cells. Although a-amanitin and cycloheximide were suppressive, actinomycin D promoted the thymidine-induced neurite extension. Morphological changes caused by thymidine were similar to those induced by cyclic AMP, rather than retinoic acid. Intracellular cAMP content was however not increased by the thymidine treatment.
Cell Differentiation↗
Host factors involved in the growth of microvirid phage alpha 3.
Host factors involed in the growth of microvirid phage alpha3 were determined using various replication mutants of Escherichia coli. The viral multiplication was dependent on functional products of dnaE, dnaF(NRDA), DNAG, and dnaZ genes. Host functions directed by dnaA, so-alled dnaH, dnaI, and dnaP genes were dispensable for the viral growth. In contrast with phiZ174 and G4, alpha3 would grow sufficiently In dnaB and dnaC(D) mutants. The viral growth was not significantly affected by host polAts, seg, and groPC mutations.
Coliphages↗
Decreased production of RNA-streptolysin S in streptococci devoid of extracellular RNase activity.
In cultures of certain streptococcal strains, RNA added as a carrier for streptolysin S (SLS) was hardly degraded, owing to deficiency of extracellular RNase activity. Production of RNA-SLS into culture supernatant was markedly reduced in the RNase-deficient streptococci. Even in these RNase-less strains, guanylic-acid rich oligonucleotides, polyG or trypan blue effectively induced SLS production, as in RNase-positive cells. These results demonstrate involvement of the streptococcal nuclease in manifestation of SLS-inducing effect of exogenous RNA. Additional data indicated that cellular growth was promoted by supplementation of RNA, in the nuclease-producing streptococci.
Bacterial Proteins↗