ABSTRACT
The genetic basis of bacteriocin (Bac) production by six strains of Staphylococcus aureus was examined. Gene transfer experiments (in which the plasmids were tagged with the erythromycin resistance transposon Tn551) and plasmid-elimination experiments by growth at 43 degrees C associated bacteriocin production with a particular plasmid in each strain. The Bac plasmids could be separated into two distinct groups: the first comprised plasmids larger than 40 kb, which did not specify immunity to bacteriocins; the second comprised small plasmids (8.0-10.4 kb) which also specified immunity to bacteriocins. The sequence relations among the small plasmids (pRJ6, pRJ9, pRJ10 and pRJ11) were investigated by comparing restriction enzyme digest patterns and by hybridization. Plasmids pRJ10 and pRJ11 were indistinguishable and very closely related to plasmid pRJ9. Plasmid pRJ6, although different from the others, shared regions of sequence homology with them. No homology was found between plasmids pRJ6 or pRJ9 and the large Bac plasmids.
Subject(s)
Bacteriocins/biosynthesis , Plasmids , Staphylococcus aureus/metabolism , Bacteriocins/chemistry , Blotting, Southern , DNA Transposable Elements , DNA, Bacterial/chemistry , Drug Resistance, Microbial , Restriction Mapping , Sensitivity and Specificity , Staphylococcus aureus/genetics , TransfectionABSTRACT
Twenty-two nitrogen-fixing Bacillus azotofixans strains were shown to produce an inhibition zone against themselves in plate assays. The B. azotofixans type strain P3L-5, chosen for further studies, produced inhibition zones against various Bacillus strains and other bacterial genera. This antibacterial substance was also produced in liquid medium and its production was enhanced in semisolid medium (0.4% agar) after 3 to 5 days of incubation. The substance was suggested to be an antibiotic and its preliminary characterization showed resistance to heat (100 degrees C, 15 minutes), to trypsin, pronase, deoxyribonuclease I, ribonuclease A, phospholipase C, ethanol, acetone, and ether, and sensitivity to strong alkali treatment. Its molecular weight was estimated to be between 3500 to 6000. After induction of B. azotofixans P3L-5 with mitomycin C or ultraviolet light, two types of particles were detected in the lysate: one similar to a phage tail and the other, less frequent, similar to a complete bacteriophage. Lysates containing these particles showed a killing effect in some but not all B. azotofixans strains, but neither the other Bacillus species nor Micrococcus were inhibited by these lysates.
Subject(s)
Bacteriocins/biosynthesis , Bacteriophages/metabolism , Bacillus/metabolism , Bacillus/ultrastructure , Bacteriocins/pharmacology , Culture Media , Drug Resistance, Microbial , Mitomycin , Mitomycins/pharmacology , Ultraviolet RaysABSTRACT
The identification of Bacillus azotofixans strains using API tests is described. Twenty-two strains were studied according to their fermentation pattern on 49 different carbohydrates. A profile of the B. azotofixans type strain is presented, together with an average profile of all strains tested. The fermentation pattern for B. azotofixans is also compared to those of the closely similar species B. polymyxa and B. macerans. These profiles may be useful for the identification of new strains.
Subject(s)
Bacillus/classification , Carbohydrate Metabolism , Bacillus/isolation & purification , Bacillus/metabolism , FermentationABSTRACT
Ten phages of Bacillus polymyxa were isolated from four different Brazilian soils. All were dsDNA-containing phages belonging to Bradley types A and B. Data obtained from electron microscopy and tests of resistance against physical and chemical agents showed that the isolates could be distributed among six different groups. Host range data were in agreement with this classification. When tested against 88 strains of 18 Bacillus species, these phages only infected B. polymyxa strains, thus revealing specificity for this species. Three phage groups lysed all 42 available B. polymyxa strains and are suggested for use in rapid identification of this species.
Subject(s)
Bacillus/classification , Bacteriophage Typing , Bacteriophages/isolation & purification , Soil Microbiology , Bacillus/physiology , Bacteriophages/classification , Bacteriophages/drug effects , Bacteriophages/physiology , Brazil , Chloroform/pharmacology , Ether/pharmacology , Hot TemperatureABSTRACT
O estudo de 137 estirpes de Staphylococcus aureus, recentemente isoladas de pacientes nao hospitalizados e de alimentos, mostrou alta percentagem de resistencia a penicilina G e percentual variavel a eritromicina, cloranfenicol, tetraciclina, canamicina, amicacina, sulfadiazina e estreptomicina. Uma estirpe produziu enterotoxina B e mal produziram enterotoxina C. Agentes estafilococcinogenicos foram detectados em 13 estirpes
Subject(s)
Humans , Penicillin G , Staphylococcus aureus , Virulence , Drug Resistance, MicrobialABSTRACT
A new Bacillus megaterium bacteriophage is characterized. It is a tailed phage with regular polyhedral head belonging to Bradley's group B. Head and tail dimensions are 56.4 and 300 nm, respectively. Lysis was restricted to strains of B. megaterium. No antigenic relationship with pumilus phage FP-1 or subtilis phage FS-1 was observed. The phage is sensitive to 60 degrees C and moderately sensitive to chloroform. The nucleic acid is double-stranded linear DNA with a G-C mole% of 38.8 and a mol wt of (53 +/- 3) X 10(6).
Subject(s)
Bacteriophages/isolation & purification , Soil Microbiology , Bacillus megaterium , Bacteriophages/growth & development , Bacteriophages/ultrastructure , Brazil , DNA, Viral/analysis , Hydrogen-Ion Concentration , Tropical Climate , Virus ReplicationABSTRACT
Foram testadas 95 estirpes de Bacillus e 10 de Staphylococcus aureus quanto a sensibilidade face a 14 fagos recem isolados de B. subtilis e 16 de B. pumilus.Todas as estirpes de S. aureus e 65 de Bacillus mostraram-se resistentes a lise por quaisquer dos fagos de Bacillus.Entre as estirpes de referencia, apenas aquelas de B.subtilis e B. pumilus foram lisadas por fagos de ambos os hospedeiros. As estirpes sensiveis recentemente isoladas foram identificadas como B. subtilis e B. pumilus Todos os fagos de B. subtilis eram especies especificos; no entanto, a maioria dos fagos de B. pumilus lisava ambas as especies. Tais dados confirmam a proximidade taxonomica destas especies
Subject(s)
Soil Microbiology , Staphylococcus aureus , Bacillus , BacteriophagesABSTRACT
Foi isolado do solo um fago de Bacillus megaterium, com aspecto morfologico anormal. Difere dos outros fagos de B. megaterium pela presenca de cabeca alongada, a semelhanca do fago BLE de B. licheniformis. Como outras caracteristicas analisadas neste fago apontou-se sensibilidade a temperatura de 60 graus C; resistencias ao cloroformio e luz ultra violeta e incapacidade de evidenciar placas de lise a 42 graus C. O fago esta constituido de ADN de dupla fita com um teor G-C de 34,7 a 36,7%
Subject(s)
Bacillus megaterium , BacteriophagesABSTRACT
Quatorze fagos de Bacilus subtilis foram isolados de 5 solos diferentes e caracterizados quanto a morfologia e suas placas de lise, estabilidade a 4oC, microscopia eletronica, propriedades antigenicas, resistencia ao calor e quanto ao espectro de lise. O uso desses criterios permitiu que estes fagos fossem classificados em 7 grupos diferentes. O grupo maior consiste de 7 fagos estaveis, relativamente resistentes ao calor, sorologicamente relacionados entre si e pertencentes ao tipo B de Bradley. Todos os outros fagos isolados pertencem ao tipo A de Bradley. Oa fagos aqui descritos, sao comparados com fagos de B.subtilis anteriormente descritos
Subject(s)
Soil Microbiology , Bacillus subtilis , Microscopy, Electron , Bacteriophage TypingABSTRACT
A plasmid with a molecular mass of 1.4 x 10(6) daltons has been identified in Staphylococcus aureus. This plasmid determines constitutive resistance to erythromycin and lincomycin and is the smallest naturally occurring element coding for antibiotic resistance in this species.