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At least 19 recordsLinked to original sources
PubMed1976

Studies on megacinogeny in Bacillus cereus. II. Bacillus cereus isolates characterized by prophage-controlled production of megacin A (phospholipase A).

Five out of a number of Bacillus cereus strains isolated from soil produced high titre specific bacteriocin (megacin A) in mitomycin C-induced cultures. In the course of cultivation with ethidium bromide, the strains gave off segregants not producing bacteriocin (cin-). The lysate of two wild strains formed plaques on the corresponding cin- bacteria. The two phages (wx23 and wx26) were identical in antigenic structure with phage wx was present in the lysate of B. cereus strain W, and converted cin- derivatives into cultures producing megacin A (phospholipase A). The phages produced plaques at 26 degrees C but not at 37 degrees C. In the lysates of the remaining three strains phages were not detected with biological and morphological methods; these cultures have been assumed to carry defective prophage genome. As the corresponding prophages are responsible for the determination of inducible phospholipase A production, phages named wx seem to form a separate group of B. cereus phages.

Bacillus cereus↗
PubMed1978

Production and characterization of two hemolysins of Bacillus cereus.

Bacillus cereus strain B-48 produced two hemolysins with molecular weights of 52,000 (H-I) and 31,000 (H-II). A mutant was isolated that produced only H-II but was identical with the wild type in all other respects. We exploited this mutant to produce H-II for study that was free of contamination by H-I. By manipulation of media composition, we produced H-I in the absence of H-II. The hemolysins were precipitated differently by ammonium sulfate, and both exhibited the Arrhenius effect when heated. Both hemolysins attached rapidly to erythrocytes; however, lysis by H-I was immediate, while lysis by H-II followed after a lag. Hemolysis by H-I and H-II increased in rate with increasing temperature and was absent at 0 degrees C. Only H-I was inhibited by cholesterol. The hemolysins of B. cereus appeared similar to the hemolysins of B. thuringiensis. H-I probably is identical with cereolysin.

Animals↗
PubMed1975

Experimental infection of rabbits with Bacillus cereus.

Bacillus cereus was able to grow and produced local infections following subcutaneous or intramuscular injection. An inflammatory response was produced with necrosis of muscle fibres and calcification. The organism was sensitive to chemotherapeutic agents on in vitro tests.

Abscess↗
PubMed1977

Role of glutamate in the sporogenesis of Bacillus cereus.

Bacillus cereus T, sporulating in a chemically defined medium under optimum conditions, requires substrate quantities of glutamate during the first 4 h of sporogenesis. Seventy percent of the glutamate utilized was catabolized to CO2 during this period, with the remaining glutamate carbon assimilated into various spore constituents, principally protein and nucleic acid. The importance of glutamate as the primary source of reducing potential and energy for early stages of spore formation was investigated. Although the relative efficiency at which tricarboxylic acid cycle intermediates substituted for glutamate was suggestive of oxidation via the tricarboxylic acid cycle, only partial inhibition of glutamate oxidation by fluoroacetate was observed.

Alanine Transaminase↗
PubMed1977

Two omega-amino acid transaminases from Bacillus cereus.

Bacillus cereus strain K-22 produced two distinct omega-amino acid transaminases, one catalyzing the transamination between beta-alanine and pyruvic acid and the other that between gamma-aminobutyric acid and alpha-ketoglutaric aic. The two enzymes were partially purified and separated from each other by various chromatographies. beta-Alanine:pyruvic acid transaminase and gamma-aminobutyric acid:alpha-ketoglutaric acid transaminase were induced by the addition of beta-alanine and gamma-aminobutyric acid, respectively, to the growth medium. beta-Alanine transaminase showed an optimum pH of 10.0 and optimum temperature of 35 degrees C, and its Km values for beta-alanine and pyruvic acid were both 1.1 mM. gamma-Aminobutyric acid, epsilon-aminocaproic acid, 2-aminoethylphosphonic acid, and propylamine showed about 30-40% of the activity of beta-alanine as amino donors, and oxalacetic acid was as good an amino acceptor as pyruvic acid. The optimum pH and temperature of gamma-aminobutyric acid transaminase were 9.0 and 50 degrees C, respectively, and its Km value for gamma-aminobutyric acid was 2.8 mM, while that for alpha-ketoglutaric acid was 2.3 mM. gamma-Aminobutyric acid and delta-aminovaleric acid were good amino donors but other omega-amino acids were virtually inactive with gamma-aminobutyric acid transaminase; alpha-ketoglutaric acid, and to a lesser extent glyoxylic acid, were active amino acceptors. Sulfhydryl reagents specifically activated gamma-aminobutyric acid transaminase.

4-Aminobutyrate Transaminase↗
PubMed1978

Bacteriocin and antibiotic resistance plasmids in Bacillus cereus and Bacillus subtilis.

A number of plasmids have been isolated as covalently closed circular DNAs from strains of Bacillus cereus and B. subtilis. From 12 out of 15 strains of B. cereus, plasmids could be isolated. Most of the B. cereus strains contained two or more plasmids. Their molecular weights ranged from 1.6 X 10(6) to 105 X 10(6). Bacteriocin production could be attributed to a 45 X 10(6)-dalton plasmid (pBC7) from B. cereus DSM 336, and tetracycline resistance to a 2.8 X 10(6) plasmid (pBC16) from B. cereus GP7. Two streptomycin-resistant strains of B. subtilis harbored plasmids of 5.2 X 10(6) and 9 X 10(6), respectively, which were, however, not correlated with the antibiotic resistance. The plasmid carrying resistance to tetracycline, pBC16, which was originally isolated from B. cereus, could be subsequently transformed in B. subtilis, where it is stably maintained.

Anti-Bacterial Agents↗
PubMed1977

Enzymic assays for isomers of 2,6-diaminopimelic acid in walls of Bacillus cereus and Bacillus megaterium.

An enzymic assay for individual isomers (meso-, LL- and DD-) of 2,6-diaminopimelate was developed. The enzyme 2,6-diaminopimelate decarboxylase specifically attacked meso-diaminopimelate and was used to measure this isomer manometrically. The meso- and LL-isomers were measured together manometrically in a coupled assay with diaminopimelate decarboxylase and diaminopimelate epimerase (which converts LL-diaminopimelate into meso-diaminopimelate). The DD-isomer was not attacked by either enzyme and was measured, as residual diaminopimelate after the coupled assay, by a colorimetric method, which was also used to measure total diaminopimelate before enzymic treatments. The coupled enzymes were also used to prepare pure DD-isomer from chemically synthesized diaminopimelate. A mixture of diaminopimelate isomers was present in walls of four strains of Bacillus megaterium [in each about 75% (w/w) meso-, 18% LL- and 7% DD-] and in walls of two strains of Bacillus cereus (about 85% meso-, 8% LL- and 7% DD-). One strain of B. cereus contained at least 95% meso-diaminopimelate, with only traces of LL- and DD-isomers. Peptidoglycan from Escherichia coli was assayed as containing at least 95% meso-isomer. The proportion of isomers in the wall of a strain of B. megaterium remained constant after growth in a variety of different media.

Amino Acid Isomerases↗
PubMed1978

Spore location patterns in sporulating doublets of Bacillus cereus and Bacillus megaterium, derived from single doublet isolates with differing sporulation geometry.

The distribution of spore loci in pairs of Bacillus cereus and B. megaterium showed different degrees of polarization from random location towards location at the old end of the sporangium. When individual doublets containing both spores at either the old or new ends of the sporangia were isolated by micromanipulation, subsequent culture showed the same spore location patterns.

Bacillus megaterium↗
PubMed1977

Dihydrodipicolinate reductases from Bacillus cereus and Bacillus megaterium.

Dyhydrodipicolinate reductases were purified 100-fold from crude extracts of B. cereus and B. megaterium and their properties were compared with those of the reductase from B. subtilis. The molecular weights of the reductases of B. cereus and B. megaterium were fount to be 155,000 and 150,000, respectively. These reductases were shown to be free of flavin, unlike the B. subtilis enzyme, which contains flavin. Both NADPH and NADH acted as coenzymes for these two reductases. NADPH being three or four times more effective than NADH. The Km values for NADPH and dihydrodipicolinate were 8 micrometer and 62 micrometer, respectively, with B. cereus reductase, and 13 micrometer and 59 micrometer with B. megaterium reductase. The pH optima of the enzymes from B. cereus and B. megaterium were pH 7.4 and 7.2, respectively. The reductases were inhibited by dipicolinate noncompetitively with respect to dihydrodipicolinate and the Ki values were 85 micrometer and 140 micrometer, respectively. Lysine and diaminopimelate were not inhibitory. The properties of the reductases from B. cereus and B. megaterium were similar, but they differed considerably from those of the B. subtilis enzyme. However, all three Bacillus reductases were markedly inhibited by dipicolinate, unlike the enzyme from E. coli.

Bacillus cereus↗
PubMedDate not supplied

[Cloning and gene expression of Bacillus cereus neutral proteinase in Bacillus subtilis cells].

The neutral proteinase gene of Bacillus cereus was cloned. Its restriction map and the direction of transcription was determined. It was shown that the neutral proteinase gene could be expressed in Bacillus cells. The thermostability of the product coded by the neutral proteinase gene and its natural analogue was explored. The obtained data indicate that the neutral proteinase of Bacillus cereus is closely related to the enzyme of Bacillus amyloliquefaciens by these parameters. It was found that the neutral proteinase of Bacillus cereus has a high sensitivity to autolysis and that leads to the decrease in the enzymes concentration in the cultural medium at the late stages of cell growth. But the possibility of stabilization the neutral proteinase by Ca2+ ions has been demonstrated.

Bacillus cereus↗
PubMed1992

The role of the pro-sequence in the processing and secretion of the thermolysin-like neutral protease from Bacillus cereus.

The Bacillus cereus cnp gene coding for the thermolysin-like neutral protease (TNP) has been cloned, sequenced, and expressed in Bacillus subtilis. The protease is first produced as a pre-pro-protein (M(r) = 61,000); the pro-peptide is approximately two-thirds of the size of the mature protein. The pro-sequence has been compared with those of six other TNPs, and significant homologies have been found. Additionally, the TNP pro-sequences are shown to be homologous to the pro-sequence of Pseudomonas aeruginosa elastase. A mutant has been constructed from cnp, in which 23 amino acids upstream from the pro-protein processing site have been deleted. This region has no homologous analogue in any of the other TNP pro-sequences. The deletion results in a delay of six to eight hours in detection of active protease in the growth medium, as well as a 75% decrease in maximum protease production. N-terminal analysis of the mutant mature protein demonstrates that the processing site is unaltered by the pro-sequence deletion. The deletion must, therefore, modulate the kinetics of processing and/or secretion of the pro-protein.

Amino Acid Sequence↗
PubMed2026

Development and application of a fast and efficient CRISPR/Cas12f -based genetic toolkit in Bacillus cereus GW-01.

Bacillus cereus GW-01, an efficient degrader of β-cypermethrin (β-CY), has a high safety profile and probiotic potential for regulating intestinal flora and fermented foods, which is difficult to genetically engineer for modification due to its restrictive modification system. This study successfully developed a CRISPR/enCas12f-based genome editing system, first selecting the plcR gene for proof-of-concept validation with 100% knockout efficiency. Subsequently, this system was utilized to delete the virulence gene nheABC in GW-01, yielding a safer probiotic strain. Compared with the wild-type strain GW-01, the probiotic-related indicators of the ΔnheABC mutant, including cell surface hydrophobicity, auto-aggregation ability and biofilm formation ability, were 80%, 90% and 2.9 (OD₅₉₅), respectively. There were no significant differences in these indicators between the mutant and the wild type. Meanwhile, the ΔnheABC mutant still maintained a high β-cypermethrin degradation efficiency of 80% at the concentration of 30 μg/mL. This work facilitates functional genomic research and genetic modification of Bacillus cereus GW-01. The established CRISPR/enCas12f system enables targeted gene deletion to explore gene functions and phenotypic mechanisms, and paves the way for its development into safe probiotics and excellent microbial chassis.

Bacillus cereus↗
PubMed1975

An insect toxin from spores of Bacillus thuringiensis and Bacillus cereus.

Spores of Bacillus thuringiensis contain a toxin active against lepidopterous larvae. This toxin can be solubilized by extraction with reagents which dissolve the protein crystal of B thuringiensis. It is inactivated by crystal-specific antiserum. Spores of Bacillus cereus contain a similar toxin although the specific activity is much lower than the spores of B. thuringiensis. The B. cereus toxin contains a single major polypeptidecomponent. Toxic activity can be solubliized from spores of both species by incubation with gut juices from Pieris brassicae.

Amino Acids↗
PubMed1975

[Report of "lethal factor" synthetized by Bacillus cereus (author's transl)].

Bacillus cereus growing in nutrition broth produces during logarithmic growth and in stationary phase a lethal factor extremely toxic for rodents. This toxin is only produced in the presence of oxygen and depends on bacterial replication. The highest titers of toxin are obtained using bacteria in a concentration of 10(7) to 10(9) per ml of nutrition broth. During regression phase of Bacillus cereus the titer of toxin declines to zero. Toxicity of the lethal factor becomes not altered in an alcaline or acidic medium. Temperatures exceeding 65 degrees C inactivate the toxin indicating its thermolability. Oral and rectal dispension of large quantities of the lethal factor does not induce toxic symptoms in rodents. However, when applicating toxin containing cultural filtrate of Bacillus cereus as an i.v., i.p., i.n. or s.c. injection it becomes highly toxic for mice, rats, hamsters, guinea pigs and rabbits. All animals injected by the different ways parenterally died.

Administration, Intranasal↗
PubMed1979

Effect of trichloroacetic acid treatment on certain properties of spores of Bacillus cereus T.

Spores of Bacillus cereus T treated with trichloroacetic acid (6.1--61.2 mM) were compared with untreated spores, and as the concentration of the chemical increased, the following alterations in spore properties were found: (1) the extent of germination decreased irrespective of the germination medium used; (2) the spores became sensitive to sodium hydroxide (1 N) and hydrochloric acid (0.27 N), but not to lysozyme (200 micrograms/ml); (3) loss of dipicolinate increased on subsequent heating; and (4) the spores became more sensitive to heat. However, trichloroacetic acid-treated spores were still viable and there was no significant change in spore components. The mechanism of action of trichloroacetic acid is discussed.

Bacillus cereus↗