Studies on transfection and transformation of protoplasts of Bacillus larvae, Bacillus subtilis, and Bacillus popilliae

Protoplasts of Bacillus larvae NRRL b-3555 and Bacillus subtilis RM125 (restrictionless, modificationless mutant) were transfected with DNA from the B. larvae bacteriophage PBL1c in the presence of polyethylene glycol. B. subtilis 168 and Bacillus popilliae NRRL B-2309M protoplasts could not be transfected with PBL1c DNA. Protoplasts of B larvae NRRL B-3555 were transformed with plasmids pC194 and pHV33 in the presence of polyethylene glycol. The frequency of transformation was much higher when the plasmids were isolated from B. larvae NRRL B-3555 transformants than when they were isolated from B. subtilis 168. These results indicate that the restriction-modification systems found in B. larvae NRRL B-3555 and B. subtilis 168 may be different. Conditions for protoplast formation and cell wall regeneration were developed for B. popilliae NRRL B-2309S. However, no transformation occurred with plasmids pC194 and pHV33 (isolated from B. subtilis 168).     

Studies on transfection and transformation of protoplasts of Bacillus larvae, Bacillus subtilis, and Bacillus popilliae.

Protoplasts of Bacillus larvae NRRL b-3555 and Bacillus subtilis RM125 (restrictionless, modificationless mutant) were transfected with DNA from the B. larvae bacteriophage PBL1c in the presence of polyethylene glycol. B. subtilis 168 and Bacillus popilliae NRRL B-2309M protoplasts could not be transfected with PBL1c DNA. Protoplasts of B larvae NRRL B-3555 were transformed with plasmids pC194 and pHV33 in the presence of polyethylene glycol. The frequency of transformation was much higher when the plasmids were isolated from B. larvae NRRL B-3555 transformants than when they were isolated from B. subtilis 168. These results indicate that the restriction-modification systems found in B. larvae NRRL B-3555 and B. subtilis 168 may be different. Conditions for protoplast formation and cell wall regeneration were developed for B. popilliae NRRL B-2309S. However, no transformation occurred with plasmids pC194 and pHV33 (isolated from B. subtilis 168).     

Methionine regeneration and aminotransferases in Bacillus subtilis,Bacillus cereus,and Bacillus anthracis

The conversion of ketomethiobutyrate to methionine has been previously examined in a number of organisms, wherein the aminotransferases responsible for the reaction have been found to be members of the Ia subfamily (L. C. Berger, J. Wilson, P. Wood, and B. J. Berger, J. Bacteriol. 183:4421-4434, 2001). The genome of Bacillus subtilis has been found to contain no subfamily Ia aminotransferase sequences. Instead, the analogous enzymes in B. subtilis were found to be members of the If subfamily. These putative aspartate aminotransferases, the yugH, ywfG, ykrV, aspB, and patA gene products, have been cloned, expressed, and characterized for methionine regeneration activity. Only YkrV was able to convert ketomethiobutyrate to methionine, and it catalyzed the reaction only when glutamine was used as amino donor. In contrast, subcellular homogenates of B. subtilis and Bacillus cereus utilized leucine, isoleucine, valine, alanine, phenylalanine, and tyrosine as effective amino donors. The two putative branched-chain aminotransferase genes in B. subtilis, ybgE and ywaA, were also cloned, expressed, and characterized. Both gene products effectively transaminated branched-chain amino acids and ketoglutarate, but only YbgE converted ketomethiobutyrate to methionine. The amino donor preference for methionine regeneration by YbgE was found to be leucine, isoleucine, valine, phenylalanine, and tyrosine. The B. subtilis ybgE gene is a member of the family III of aminotransferases and falls in a subfamily designated here IIIa. Examination of B. cereus and Bacillus anthracis genome data found that there were no subfamily IIIa homologues in these organisms. In both B. cereus and B. anthracis, two putative branched-chain aminotransferases and two putative D-amino acid aminotransferases were discovered as members of subfamily IIIb. These four sequences were cloned from B. cereus, expressed, and characterized. Only the gene product from the sequence designated Bc-BCAT2 was found to convert ketomethiobutyrate to methionine, with an amino donor preference of leucine, isoleucine, valine, phenylalanine, and tyrosine. The B. anthracis homologue of Bc-BCAT2 was also cloned, expressed, and characterized and was found to be identical in activity. The aminooxy compound canaline was found to be an uncompetitive inhibitor of B. subtilis YbgE and also inhibited growth of B. subtilis and B. cereus in culture.     

Improvement in the growth performance of white shrimp, Litopenaeus vannamei, by a protease-producing probiotic, Bacillus subtilis E20, from natto

Aims:  To isolate and identify a benefic bacterium, Bacillus subtilis E20, from natto (fermented soybeans), and incorporate it into shrimp feed to promote shrimp growth performance.
Methods and Results:  A protease-producing bacterium, E20, isolated from natto was identified as B. subtilis by an API 50 CHB kit and the 16S rDNA sequence. B. subtilis E20 was able to grow at a broad range of temperatures (10–50°C), pH values (5–10), and NaCl levels (0–9%). The best culture conditions for B. subtilis E20 to produce the protease were 40°C, a pH of 6–8 and 0% NaCl. No shrimp died after being injected with B. subtilis E20 [up to 10⁹ colony-forming units (CFU) per shrimp]. Bacillus subtilis E20 was incorporated in diets at the levels of 0 (control), 10⁶, 10⁷, and 10⁸ CFU kg⁻¹ for shrimp grow-out culture, and results showed that after feeding on B. subtilis E20-containing diets (10⁸ CFU kg⁻¹ of diet), shrimp had excellent growth performance and production compared to the control because protease activities in the digestive tract were improved by B. subtilis E20.
Conclusions:  Bacillus subtilis E20 isolated from natto is a great protease producer and is able to improve shrimp growth performance through increasing the digestibility of food.
Significance and Impact of the Study:  Results suggest that B. subtilis E20 is a potential candidate for use as a probiotic to improve shrimp growth performance, and consequently reduce feed costs.     

Comparative growth analysis of the facultative anaerobes Bacillus subtilis,Bacillus licheniformis,and Escherichia coli

Bacillus subtilis anaerobic respiration and fermentative growth capabilities were compared to two other facultative anaerobes, Bacillus licheniformis and Escherichia coli. In glycerol defined medium, B. subtilis grew with nitrate, but not nitrite or fumarate, while B. licheniformis grew with nitrate or fumarate, but not nitrite. Growth of E. coli occurred in glycerol defined medium with either nitrate, nitrite, or fumarate. In order to grow by fermentation, B. subtilis required both glucose and pyruvate, while B. licheniformis and E. coli were capable of using either glucose or pyruvate.     

Effect of pH on Sporulation of Bacillus Stearothermophilus

An improved broth medium was developed for high growth yields of Bacillus subtilis var. niger NCIB 8649, Bacillus cereus NCIB 9373, and Bacillus stearothermophilus NCIB 8919 and ATCC 7953. Sporulation was abundant (1.1 times 10-8 B. subtilis var. niger and 9.2 times 10-7 B. cereus per ml) at an initial pH of 7.0. Sporulation of both strains of B. stearothermophilus took place (1.9 times 10-7 and 2.4 times 10-7/ml, respectively) in this medium when initial pH values of 7.7 to 8.7 were used.     

Whole-genome sequences of Bacillus subtilis and close relatives

We sequenced four strains of Bacillus subtilis and the type strains for two closely related species, Bacillus vallismortis and Bacillus mojavensis. We report the high-quality Sanger genome sequences of B. subtilis subspecies subtilis RO-NN-1 and AUSI98, B. subtilis subspecies spizizenii TU-B-10(T) and DV1-B-1, Bacillus mojavensis RO-H-1(T), and Bacillus vallismortis DV1-F-3(T).     

CSF, a species-specific extracellular signaling peptide for communication among strains of Bacillus subtilis and Bacillus mojavensis

ComX and CSF are Bacillus subtilis extracellular signaling peptides. Many different strains of B. subtilis do not communicate due to strain-specific variation of ComX. We demonstrate that CSF is a species-specific signaling molecule that partially compensates for the lack of ComX-mediated communication between different strains of B. subtilis.     

Comparative genome analysis of Bacillus cereus group genomes with Bacillus subtilis

Genome features of the Bacillus cereus group genomes (representative strains of Bacillus cereus, Bacillus anthracis and Bacillus thuringiensis sub spp. israelensis) were analyzed and compared with the Bacillus subtilis genome. A core set of 1381 protein families among the four Bacillus genomes, with an additional set of 933 families common to the B. cereus group, was identified. Differences in signal transduction pathways, membrane transporters, cell surface structures, cell wall, and S-layer proteins suggesting differences in their phenotype were identified. The B. cereus group has signal transduction systems including a tyrosine kinase related to two-component system histidine kinases from B. subtilis. A model for regulation of the stress responsive sigma factor sigmaB in the B. cereus group different from the well studied regulation in B. subtilis has been proposed. Despite a high degree of chromosomal synteny among these genomes, significant differences in cell wall and spore coat proteins that contribute to the survival and adaptation in specific hosts has been identified.     

Characterization of Bacillus subtilis bacteriophages

Brodetsky, Anna M. (University of California, Los Angeles), and W. R. Romig. Characterization of Bacillus subtilis bacteriophages. J. Bacteriol. 90:1655-1663. 1965.-A group of six phages, SP5, SP6, SP7, SP8, SP9, and SP13, which use the Marburg strain of Bacillus subtilis as host was characterized. These phages, referred to as group 1, were examined for the following properties: host range, plaque morphology, stability, adsorption kinetics, one-step growth characteristics, calcium requirements, serum neutralization, thermal inactivation, and inactivation by ultraviolet irradiation. Five unrelated B. subtilis phages, SP3, SP10, PBS1, SP alpha, and SP beta, were included in the studies. When first isolated, none of the group 1 phages was able to replicate efficiently on B. subtilis SB19, a mutant of the "transforming" B. subtilis 168. Host range mutants capable of growth in SB19 were isolated for all of the group 1 phages except SP13, and are designated the "star" phages (SP5* through SP9*). For characterization, SB19 was used as host for the star phages, and another B. subtilis mutant, 168B, was host for SP13.     

Formaldehyde gas inactivation of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials

AIMS: To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using formaldehyde gas. METHODS AND RESULTS: B. anthracis, B. subtilis, and G. stearothermophilus spores were dried on seven types of indoor surfaces and exposed to approx. 1100 ppm formaldehyde gas for 10 h. Formaldehyde exposure significantly decreased viable B. anthracis, B. subtilis, and G. stearothermophilus spores on all test materials. Significant differences were observed when comparing the reduction in viable spores of B. anthracis with B. subtilis (galvanized metal and painted wallboard paper) and G. stearothermophilus (industrial carpet and painted wallboard paper). Formaldehyde gas inactivated>or=50% of the biological indicators and spore strips (approx. 1x10(6) CFU) when analyzed after 1 and 7 days. CONCLUSIONS: Formaldehyde gas significantly reduced the number of viable spores on both porous and nonporous materials in which the two surrogates exhibited similar log reductions to that of B. anthracis on most test materials. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provide new comparative information for the decontamination of B. anthracis spores with surrogates on indoor surfaces using formaldehyde gas.     

MotPS is the stator-force generator for motility of alkaliphilic Bacillus, and its homologue is a second functional Mot in Bacillus subtilis

The stator-force generator that drives Na+-dependent motility in alkaliphilic Bacillus pseudofirmus OF4 is identified here as MotPS, MotAB-like proteins with genes that are downstream of the ccpA gene, which encodes a major regulator of carbon metabolism. B. pseudofirmus OF4 was only motile at pH values above 8. Disruption of motPS resulted in a non-motile phenotype, and motility was restored by transformation with a multicopy plasmid containing the motPS genes. Purified and reconstituted MotPS from B. pseudofirmus OF4 catalysed amiloride analogue-sensitive Na+ translocation. In contrast to B. pseudofirmus, Bacillus subtilis contains both MotAB and MotPS systems. The role of the motPS genes from B. subtilis in several motility-based behaviours was tested in isogenic strains with intact motAB and motPS loci, only one of the two mot systems or neither mot system. B. subtilis MotPS (BsMotPS) supported Na+-stimulated motility, chemotaxis on soft agar surfaces and biofilm formation, especially after selection of an up-motile variant. BsMotPS also supported motility in agar soft plugs immersed in liquid; motility was completely inhibited by an amiloride analogue. BsMotPS did not support surfactin-dependent swarming on higher concentration agar surfaces. These results indicate that BsMotPS contributes to biofilm formation and motility on soft agar, but not to swarming, in laboratory strains of B. subtilis in which MotAB is the dominant stator-force generator. BsMotPS could potentially be dominant for motility in B. subtilis variants that arise in particular niches.     

Decontamination assessment of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surfaces using a hydrogen peroxide gas generator

AIMS: To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas. METHODS AND RESULTS: Bacillus anthracis, B. subtilis, and G. stearothermophilus spores were dried on seven types of indoor surfaces and exposed to > or =1000 ppm hydrogen peroxide gas for 20 min. Hydrogen peroxide exposure significantly decreased viable B. anthracis, B. subtilis, and G. stearothermophilus spores on all test materials except G. stearothermophilus on industrial carpet. Significant differences were observed when comparing the reduction in viable spores of B. anthracis with both surrogates. The effectiveness of gaseous hydrogen peroxide on the growth of biological indicators and spore strips was evaluated in parallel as a qualitative assessment of decontamination. At 1 and 7 days postexposure, decontaminated biological indicators and spore strips exhibited no growth, while the nondecontaminated samples displayed growth. CONCLUSIONS: Significant differences in decontamination efficacy of hydrogen peroxide gas on porous and nonporous surfaces were observed when comparing the mean log reduction in B. anthracis spores with B. subtilis and G. stearothermophilus spores. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provide comparative information for the decontamination of B. anthracis spores with surrogates on indoor surfaces using hydrogen peroxide gas.     

Cloning in Bacillus subtilis of temperature-dependent promoter fragments from Bacillus stearothermophilus and Bacillus subtilis

Abstract Using promoter-probe plasmids, more than 200 promoter-containing fragments from Bacillus stearothermophilus and Bacillus subtilis were cloned in B. subtilis . Among these, 15 promoter fragments were highly temperature-dependent in activity compared to the promoter sequence (TTGAAA for the −35 region, TATAAT for the −10 region) of the amylase gene, amyT , from B. stearothermophilus . Some fragments exhibited higher promoter activities at elevated temperature (48°C), others showed higher activities at lower temperature (30°C). Active promoter fragments at higher and lower temperatures were obtained mainly from the thermophile ( B. stearothermophilus ) and the mesophile ( B. subtilis ), respectively. A promoter fragment active at high temperature was sequenced, and the feature of the putative promoter region was discussed.     

Molecular cloning in Bacillus subtilis of a Bacillus licheniformis gene encoding a thermostable alpha amylase

A resident-plasmid cloning system developed for Bacillus subtilis has been used to isolate recombinant plasmids carrying DNA from Bacillus licheniformis which confer alpha-amylase activity on alpha-amylase-negative mutants of B. subtilis. These plasmids contain a 3550-bp insert at the EcoRI site of the plasmid pBD64. Subcloning various lengths of the B. licheniformis DNA has localised the gene to a 2550-bp BclI fragment. We present evidence that the cloned fragment codes for a B. licheniformis heat-stable alpha-amylase with a temperature optimum of 93 degrees C. The foreign gene is expressed efficiently in B. subtilis and is stably maintained.     

The safety of Bacillus subtilis and Bacillus indicus as food probiotics

Aims:  To conduct in vitro and in vivo assessments of the safety of two species of Bacillus , one of which, Bacillus subtilis , is in current use as a food supplement.
Methods and Results:  Cultured cell lines, Caco-2, HEp-2 and the mucus-producing HT29-16E cell line, were used to evaluate adhesion, invasion and cytotoxicity. The Natto strain of B. subtilis was shown to be able to invade and lyse cells. Neither species was able to adhere significantly to any cell line. The Natto strain was also shown to form biofilms. No strain produced any of the known Bacillus enterotoxins. Disc-diffusion assays using a panel of antibiotics listed by the European Food Safety Authority (EFSA) showed that only Bacillus indicus carried resistance to clindamycin at a level above the minimum inhibitory concentration breakpoints set by the EFSA. In vivo assessments of acute and chronic dosing in guinea pigs and rabbits were made. No toxicity was observed in animals under these conditions.
Conclusions:  Bacillus indicus and B. subtilis should be considered safe for oral use although the resistance of B. indicus to clindamycin requires further study.
Significance and Impact of the Study:  The results support the use of B. subtilis and B. indicus strains as food supplements.     

Unrelatedness of Bacillus amyloliquefaciens and Bacillus subtilis

Eight strains of highly amylolytic, sporeforming bacilli (hereafter referred to as Bacillus amyloliquefaciens) were compared with respect to their taxonomic relationship to B. subtilis. The physiological-biochemical properties of these two groups of organisms showed that B. amyloliquefaciens differed from B. subtilis by their ability to grow in 10% NaCl, characteristic growth on potato plugs, increased production of alpha-amylase, and their ability to ferment lactose with the production of acid. The base compositions of the deoxyribonucleic acid (DNA) of the B. subtilis strains consistently fell in the range of 41.5 to 43.5% guanine + cytosine (G + C), whereas that of the B. amyloliquefaciens strains was in the 43.5 to 44.9% G + C range. Hybrid formation between B. subtilis W23 and B. amyloliquefaciens F DNA revealed only a 14.7 to 15.4% DNA homology between the two species. Transducing phage, SP-10, was able to propagate on B. subtilis W23 and B. amyloliquefaciens N, and would transduce B. subtilis 168 (indole(-)) and B. amyloliquefaciens N-10 (arginine(-)) to prototrophy with a frequency of 3.9 x 10(-4) and 2.4 x 10(-5) transductants per plaque-forming unit, respectively. Attempts to transduce between the two species were unsuccessful. These data show that Bacillus amyloliquefaciens is a valid species and should not be classified as a strain or variety of B. subtilis.     

Cloning and sequencing of a gene from Bacillus amyloliquefaciens that complements mutations of the sporulation gene spoIID in Bacillus subtilis

A segment of DNA from Bacillus amyloliquefaciens, which complemented a mutant sporulation gene, spoIID68, in Bacillus subtilis, was cloned into a derivative of the temperate bacteriophage phi 105. The segment of DNA included an entire structural gene and complemented the mutation spoIID298, in addition to spoIID68, in B. subtilis. The nucleotide sequence of the gene from B. amyloliquefaciens was determined and compared with that of the B. subtilis gene; 74% homology was found in the coding region. Amino acid primary sequences derived from the nucleotide sequences of the two genes were also compared. The gene from B. amyloliquefaciens coded for a protein of 344 amino acid residues, one more than the protein coded by the corresponding gene from B. subtilis. Comparison of the primary amino acid sequences of the two genes showed that 78% of the residues were completely conserved and 8% were semi-conserved. Variation, however, was not random, i.e. some segments were much more highly conserved than others. Both proteins had a hydrophobic region at the N-terminus.