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Genetic map of the Bacillus stearothermophilus NUB36 chromosome.

A circular genetic map of Bacillus stearothermophilus NUB36 was constructed by transduction with bacteriophage TP-42C and protoplast fusion. Sixty-four genes were tentatively assigned a cognate Bacillus subtilis gene based on growth response to intermediates or end products of metabolism, cross-feeding, accumulation of intermediates, or their relative order in a linkage group. Although the relative position of many genes on the Bacillus stearothermophilus and Bacillus subtilis genetic map appears to be similar, some differences were detected. The tentative order of the genes in the Bacillus stearothermophilus aro region is aspB-aroBAFEC-tyrA-hisH-(trp), whereas it is aspB-aroE-tyrA-hisH-(trp)-aroHBF in Bacillus subtilis. The aroA, aroC, and aroG genes in Bacillus subtilis are located in another region. The tentative order of genes in the trp operon of Bacillus stearothermophilus is trpFCDABE, whereas it is trpABFCDE in Bacillus subtilis.

Bacteriophages↗

The autolytic phenotype of the Bacillus cereus group.

AIM: To determine the autolytic phenotype of five species in the Bacillus cereus group. METHODS AND RESULTS: The autolytic rate of 96 strains belonging to five species in the B. cereus group was examined under starvation conditions at pH 6, 6.5 and 8.5 in different buffers. The autolytic rate was strain-dependent with a wide variability at pH 6, but higher and more uniform at pH 6.5. At pH 8.5, and respect to the extent of autolysis at pH 6.5, it was relatively low for most of the strains with the lowest values between 13 and 52% in Bacillus mycoides and Bacillus pseudomycoides. Peptidoglycan hydrolase patterns evaluated by renaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis using cells of Bacillus thuringiensis ssp. tolworthi HD125 as an indicator, revealed complex profiles with lytic bands of about 90, 63, 46, 41, 38, 32, 28 and 25 kDa in B. cereus, B. thuringiensis and Bacillus weihenstephanensis. Bacillus mycoides and B. pseudomycoides had simpler profiles with lytic bands of 63, 46 and 38 kDa. Changes in the autolytic pattern were observed for cells harvested at the stationary phase of growth (72 h) showing an increase in the intensity of the 25 kDa band in the case of B. cereus, B. thuringiensis and B. weihenstephanensis, while no changes were observed for B. mycoides. Using Micrococcus lysodeicticus and Listeria monocytogenes as indicators lytic activity was retained by proteins of 63, 46, 38, 32 and 25 kDa and a new one of about 20 kDa in B. mycoides. Growth in the different media did not affect the autolytic pattern. NaCl abolished the activity of all the peptidoglycan hydrolases except for those of B. mycoides and B. weihenstephanensis. Lytic activity was retained in the presence of MgCl(2), MnCl(2) and EDTA and increased at basic pH. CONCLUSIONS: Bacillus cereus/B. thuringiensis/B. weihenstephanensis showed a high extent of autolysis around neutral pH, even though they presented relatively complex autolysin profiles at alkaline pH. Bacillus mycoides/B. pseudomycoides had a higher extent of autolysis at acidic pH and a simpler autolysin pattern. SIGNIFICANCE AND IMPACT OF THE STUDY: Information on the autolytic phenotype expand the phenotypic characterization of the different species in the B. cereus group.

Bacillus cereus↗

In vitro digestibility of bacillus fermented soya bean.

Bacillus fermented legume products include among others dawadawa and soumbala made from African locust bean, and natto and kinema made from soya bean. Bacillus subtilis is the dominant species involved in the fermentation. During Bacillus fermentation for 48 h of autoclaved soya bean the quantity of soluble and dialyzable matter increased from 22% and 6% up to 65% and 40%, respectively. Protein and carbohydrate degradation during fermentation of soya bean with several Bacillus spp. was investigated and appeared to be substantial during the first 18 h of fermentation resulting in the release of high levels of peptides and oligosaccharides. In vitro digestibility was increased from 29% up to 33-43% after Bacillus fermentation for 48 h. It was shown that Bacillus spp. were able to degrade soya bean macromolecules to a large extent resulting in water-soluble low molecular weight compounds. In vitro digestion of Bacillus fermented soya bean using gastrointestinal enzymes only slightly increased the amount of dialyzable matter, which clearly demonstrated the beneficial effect of Bacillus fermentation on food nutrient availability.

Absorption↗

Detection of the dipicolinic acid biomarker in Bacillus spores using Curie-point pyrolysis mass spectrometry and Fourier transform infrared spectroscopy.

Thirty-six strains of aerobic endospore-forming bacteria confirmed by polyphasic taxonomic methods to belong to Bacillus amyloliquefaciens, Bacillus cereus, Bacillus licheniformis, Bacillus megaterium, Bacillus subtilis (including Bacillus niger and Bacillus globigii), Bacillus sphaericus, and Brevi laterosporus were grown axenically on nutrient agar, and vegetative and sporulated biomasses were analyzed by Curie-point pyrolysis mass spectrometry (PyMS) and diffuse reflectance-absorbance Fourier-transform infrared spectroscopy (FT-IR). Chemometric methods based on rule induction and genetic programming were used to determine the physiological state (vegetative cells or spores) correctly, and these methods produced mathematical rules which could be simply interpreted in biochemical terms. For PyMS it was found that m/z 105 was characteristic and is a pyridine ketonium ion (C6H3ON+) obtained from the pyrolysis of dipicolinic acid (pyridine-2,6-dicarboxylic acid; DPA), a substance found in spores but not in vegetative cells; this was confirmed using pyrolysis-gas chromatography/mass spectrometry. In addition, a pyridine ring vibration at 1447-1439 cm-1 from DPA was found to be highly characteristic of spores in FT-IR analysis. Thus, although the original data sets recorded hundreds of spectral variables from whole cells simultaneously, a simple biomarker can be used for the rapid and unequivocal detection of spores of these organisms.

Bacillus↗

Transbilayer movement of fluorescent phospholipids in Bacillus megaterium membrane vesicles.

We investigated the transbilayer movement or flip-flop of phospholipids in vesicles derived from the cytoplasmic membrane of Bacillus megaterium. Since common assay techniques were found to be inapplicable to the Bacillus system, we exploited and elaborated a newly described method in which fluorescent phospholipids (1-myristoyl-2-C6-NBD phospholipids) are used as tracers to monitor flip-flop. These lipids were introduced into Bacillus vesicles from synthetic donor vesicles containing a fluorescence quencher. Transport was measured by monitoring the increase in fluorescence as the tracers departed the quenched environment of the donor vesicle and entered first the outer membrane leaflet and subsequently the inner leaflet of Bacillus vesicles. Independent experiments involving cobalt quenching of NBD fluorescence provided results consistent with the existence of pools of fluorescent phospholipid in the outer and inner leaflets of Bacillus vesicles at the completion of transport. Using the assay we show that phospholipid flip-flop in Bacillus vesicles occurs rapidly (half-time approximately 30 s at 37 degrees C) with no preference for a particular phospholipid headgroup and that it is sensitive to proteolysis. We also establish that flip-flop does not occur in synthetic phospholipid vesicles or vesicles made from Bacillus phospholipids. We conclude that Bacillus vesicles possess the ability to promote rapid transbilayer movement of phospholipids, and that the transport is probably protein (flippase)-mediated.

4-Chloro-7-nitrobenzofurazan↗

Bacillus pseudomycoides sp. nov.

Previous DNA relatedness studies showed that strains identified as Bacillus mycoides segregated into two genetically distinct yet phenotypically similar groups, one being B. mycoides sensu stricto and the other, an unclassified taxon. In the present study, the taxonomic position of this second group was assessed by measuring DNA relatedness and determining phenotypic characteristics of an increased number of B. mycoides strains. Also determined was the second group's 16S RNA gene sequence. The 36 B. mycoides strains studied segregated into two genetically distinct groups showing DNA relatedness of about 30%; 18 strains represented the species proper and 18 the second group with intragroup DNA relatedness for both groups ranging from 70 to 100%. DNA relatedness to the type strains of presently recognized species with G+C contents of approximately 35 mol% (Bacillus alcalophilus, Bacillus cereus, Bacillus circulans, Bacillus lentus, Bacillus megaterium and Bacillus sphaericus) ranged from 22 to 37%. Although shown to be genetically distinct taxa, the two B. mycoides groups exhibited highly similar (98%) 16S RNA sequences. Phylogenetic analyses showed that both B. mycoides and the second group clustered closely with B. cereus. Although not distinguishable by physiological and morphological characteristics, the two B. mycoides groups and B. cereus were clearly separable based on fatty acid composition. The data established that the second B. mycoides group merits recognition as a new species for which the name Bacillus pseudomycoides is proposed. The type stain is NRRL B-617(T).

Bacillus↗

Bacillus endophyticus sp. nov., isolated from the inner tissues of cotton plants (Gossypium sp.).

Four strains of aerobic, endospore-forming bacteria were isolated from the inner tissues of healthy cotton plants (Gossypium sp., Dushanbe, Tajikistan). The organisms had identical randomly amplified polymorphic DNA patterns that distinguished them from other bacilli that are commonly isolated from plant tissues, e.g. Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus pumilus and Bacillus subtilis. PCR amplification of 16S-23S rRNA spacer regions suggested that the four strains could be assigned to two highly related taxa, which correlated with differences in cell morphology. However, the cloned spacer region provided a simple and specific hybridization probe for all four strains. The virtually complete 16S rDNA sequences were prepared for representatives of the two groups (strains 2DT(T) and 12DX) and differed by only two bases, thus supporting classification of the four strains in a single taxon at the species level. Phylogenetic analyses indicated that strain 2DT(T) belonged to the genus Bacillus and was most closely related to Bacillus sporothermodurans DSM 10599T with a sequence similarity of 94.8%. It is concluded that the four strains belong to a novel species of Bacillus for which the name Bacillus endophyticus sp. nov. is proposed. The type strain is 2DT(T) (= UCM B-5715T = CIP 106778T).

Bacillus↗

A numerical classification of the genus Bacillus.

Three hundred and sixty-eight strains of aerobic, endospore-forming bacteria which included type and reference cultures of Bacillus and environmental isolates were studied. Overall similarities of these strains for 118 unit characters were determined by the SSM, SJ and DP coefficients and clustering achieved using the UPGMA algorithm. Test error was within acceptable limits. Six cluster-groups were defined at 70% SSM, which corresponded to 69% SP and 48-57% SJ. Groupings obtained with the three coefficients were generally similar but there were some changes in the definition and membership of cluster-groups and clusters, particularly with the SJ coefficient. The Bacillus strains were distributed among 31 major (4 or more strains), 18 minor (2 or 3 strains) and 30 single-member clusters at the 83% SSM level. Most of these clusters can be regarded as taxospecies. The heterogeneity of several species, including Bacillus brevis, B. circulans, B. coagulans, B. megateriun, B. sphaericus and B. stearothermophilus, has been indicated and the species status of several taxa of hitherto uncertain validity confirmed. Thus on the basis of the numerical phenetic and appropriate (published) molecular genetic data, it is proposed that the following names be recognized; Bacillus flexus (Batchelor) nom. rev., Bacillus fusiformis (Smith et al.) comb. nov., Bacillus kaustophilus (Prickett) nom. rev., Bacillus psychrosaccharolyticus (Larkin & Stokes) nom. rev. and Bacillus simplex (Gottheil) nom. rev. Other phenetically well-defined taxospecies included 'B. aneurinolyticus', 'B. apiarius', 'B. cascainensis', 'B. thiaminolyticus' and three clusters of environmental isolates related to B. firmus and previously described as 'B. firmus-B. lentus intermediates'. Future developments in the light of the numerical phenetic data are discussed.

Bacillus↗

Rope-producing strains of Bacillus spp. from wheat bread and strategy for their control by lactic acid bacteria.

Two types of white wheat bread (high- and low-type loaves) were investigated for rope spoilage. Thirty of the 56 breads tested developed rope spoilage within 5 days; the high-type loaves were affected by rope spoilage more than the low-type loaves. Sixty-one Bacillus strains were isolated from ropy breads and were characterized on the basis of their phenotypic and genotypic traits. All of the isolates were identified as Bacillus subtilis by biochemical tests, but molecular assays (randomly amplified polymorphic DNA PCR assay, denaturing gradient gel electrophoresis analysis, and sequencing of the V3 region of 16S ribosomal DNA) revealed greater Bacillus species variety in ropy breads. In fact, besides strains of B. subtilis, Bacillus licheniformis, Bacillus cereus, and isolates of Bacillus clausii and Bacillus firmus were also identified. All of the ropy Bacillus isolates exhibited amylase activity, whereas only 32.4% of these isolates were able to produce ropiness in bread slices after treatment at 96 degrees C for 10 min. Strains of lactic acid bacteria previously isolated from sourdough were first selected for antirope activity on bread slices and then used as starters for bread-making experiments. Prevention of growth of approximately 10(4) rope-producing B. subtilis G1 spores per cm(2) on bread slices for more than 15 days was observed when heat-treated cultures of Lactobacillus plantarum E5 and Leuconostoc mesenteroides A27 were added. Growth of B. subtilis G1 occurred after 7 days in breads started with Saccharomyces cerevisiae T22, L. plantarum E5, and L. mesenteroides A27.

Antibiosis↗

Distribution and identification of proteolytic Bacillus spp. in paddy field soil under rice cultivation.

Proteolytic bacteria in paddy field soils under rice cultivation were characterized and enumerated using azocoll agar plates. Bacillus spp. were the proteolytic bacteria that were most frequently present, comprising 59% of the isolates. They were always the numerically dominant proteolytic bacteria isolated from three kinds of fertilizer treatments (yearly application of rice-straw compost and chemical fertilizer, yearly application of chemical fertilizer, and no fertilizer application) and at three different stages of rice development (vegetative growth stage, maximal tillering stage, and harvest stage). Of the 411 proteolytic bacteria isolated, 124 isolates had stronger proteolytic activity than others on the basis of gelatin liquefaction tests and most of them were Bacillus spp. (100% in 1989 and 92.4% in 1991). Bacillus subtilis and Bacillus cereus were the main bacteria of this group and Bacillus mycoides, Bacillus licheniformis, and Bacillus megaterium were also present. We conclude that these Bacillus spp. are the primary source of soil protease in these paddy fields.

Azo Compounds↗

Developments in the use of Bacillus species for industrial production.

Bacillus species continue to be dominant bacterial workhorses in microbial fermentations. Bacillus subtilis (natto) is the key microbial participant in the ongoing production of the soya-based traditional natto fermentation, and some Bacillus species are on the Food and Drug Administration's GRAS (generally regarded as safe) list. The capacity of selected Bacillus strains to produce and secrete large quantities (20-25 g/L) of extracellular enzymes has placed them among the most important industrial enzyme producers. The ability of different species to ferment in the acid, neutral, and alkaline pH ranges, combined with the presence of thermophiles in the genus, has lead to the development of a variety of new commercial enzyme products with the desired temperature, pH activity, and stability properties to address a variety of specific applications. Classical mutation and (or) selection techniques, together with advanced cloning and protein engineering strategies, have been exploited to develop these products. Efforts to produce and secrete high yields of foreign recombinant proteins in Bacillus hosts initially appeared to be hampered by the degradation of the products by the host proteases. Recent studies have revealed that the slow folding of heterologous proteins at the membrane-cell wall interface of Gram-positive bacteria renders them vulnerable to attack by wall-associated proteases. In addition, the presence of thiol-disulphide oxidoreductases in B. subtilis may be beneficial in the secretion of disulphide-bond-containing proteins. Such developments from our understanding of the complex protein translocation machinery of Gram-positive bacteria should allow the resolution of current secretion challenges and make Bacillus species preeminent hosts for heterologous protein production. Bacillus strains have also been developed and engineered as industrial producers of nucleotides, the vitamin riboflavin, the flavor agent ribose, and the supplement poly-gamma-glutamic acid. With the recent characterization of the genome of B. subtilis 168 and of some related strains, Bacillus species are poised to become the preferred hosts for the production of many new and improved products as we move through the genomic and proteomic era.

Anti-Bacterial Agents↗

Determination of beta-lactamase activities and antibiotic susceptibility of some Bacillus strains causing food poisoning.

Some Bacillus species are important food pathogens. For example, B. cereus is an opportunistic pathogen found in raw milk that is a common cause of food poisoning. It is of interest to investigate the virulant profiles of Bacillus strains isolated from foods and samples associated with food-poisoning outbreaks. Nineteen Bacillus strains were isolated from various milk samples. Beta-lactamase enzyme activities of these Bacillus strains were evaluated with iodometric and chromogenic cephalosporin (nitrocefin) test methods. Five of 19 Bacillus strains isolated were positive for beta-lactamase activity. Clavulanate-amoxycillin and cephazolin were chosen to test the antibiotic susceptibilities of the beta-lactamase positive and negative Bacillus strains. Of the five beta-lactamase positive Bacillus strains, three were susceptible, and two strains intermediate to clavulanate-amoxycillin; one was susceptible, and four strains were intermediate to cephazolin. None of the beta-lactamase positive Bacillus strains was resistant to both antibiotics. Of the 14 beta-lactamase negative strains, five were susceptible to clavulanate-amoxycillin, four strains were intermediate, and five strains were resistant; three were susceptible, one intermediate, and ten beta-lactamase negative strains were resistant to cephazolin.

Amoxicillin↗

Bacillus species isolates from cerebrospinal fluid in patients without shunts.

Of 849 CSF cultures done at Hartford Hospital, nine were positive for nonanthrax Bacillus species. Differentiation of true nonanthrax Bacillus species infection from contamination requires careful consideration of the clinical findings, the clinical course, and the laboratory data. In seven patients the nonanthrax Bacillus species represented contamination. In two patients the nonanthrax Bacillus species represented true infection. In one of these infected patients, nonanthrax Bacillus species complicated a cranial gun shot wound. Bacillus cereus meningitis developed in the second patient, a premature infant, following sepsis from a contaminated IV catheter. Nonanthrax Bacillus species, especially B cereus, can be resistant to penicillins and cephalosporins when nonanthrax Bacillus species infections are being treated, susceptibility testing should always be performed.

Adult↗

[Cloning of the genes controlling the biosynthesis of bacitracin in Bacillus licheniformis].

The DNA fragment from bacitracin-producing Bacillus licheniformis strain is cloned on pMX39 vector plasmid in Bacillus subtilis cells. Bacillus subtilis cells carrying the cloned fragment inhibit the growth of bacitracin-sensitive tester strain. The observed inhibition of growth is due to the production by Bacillus subtilis of bacteriocin substance that is identified as bacitracin by TLC-chromatography. In contrast to the data published earlier it is shown that Bacillus subtilis can in fact produce the small amounts of bacitracin. Introduction of the cloned Bacillus licheniformis DNA into Bacillus subtilis cells stimulates this bacitracin production. The restriction site map of the Bacillus licheniformis chromosomal region bearing the cloned fragment is constructed.

Bacillus↗

Experience with bacillus Calmette-Guerin in patients with superficial bladder carcinoma.

A randomized study was done on 49 patients with a history of recurrent superficial transitional cell carcinoma of the bladder to determine if the frequency of tumor recurrence could be lessened. The patients were treated with 6 weekly instillations of Tice strain bacillus Calmette-Guerin or thio-tepa, followed by instillations every 2 weeks for 3 months and every month until a recurrence developed or the patients had been treated for 2 years. Twelve additional patients who had previously failed on thio-tepa were placed on the bacillus Calmette-Guerin protocol. There have been no recurrences in the bacillus Calmette-Guerin group, while 9 patients (40 per cent) in the thio-tepa group suffered recurrences. All of the patients treated with bacillus Calmette-Guerin had symptoms of bladder irritability after each instillation. The same type of irritability occurred in 7 patients (25 per cent) in the thio-tepa group. Severe complications occurred in 11 patients treated with bacillus Calmette-Guerin (28 per cent), 4 of whom required hospitalization. Another 12 patients with visible transitional cell carcinoma were treated with weekly instillations of bacillus Calmette-Guerin. Of these patients 6 had total resolution after 18 weekly instillations and 2 had no detectable tumor after 24 weeks of therapy. Two patients were free of tumor after 6 instillations. Of 7 patients with carcinoma in situ treated with weekly instillations of bacillus Calmette-Guerin 5 had complete resolution of the cellular atypia after 18 weeks of therapy. These studies confirm and extend those of others by demonstrating that bladder instillations of bacillus Calmette-Guerin are effective in reducing the recurrence rate in patients with superficial bladder tumor and can eliminate existing tumor in some patients. Symptoms of bladder irritability occur to a varying extent in every patient, and severe systemic toxicity occurred in 28 per cent of the patients.

BCG Vaccine↗

Cilia-associated respiratory (CAR) bacillus infection in conventionally reared rabbits.

This study was designed to investigate the prevalence of Cilia-associated respiratory (CAR) bacillus infection in rabbits reared for meat production in Italy and to correlate the presence of CAR bacillus with inflammatory lesions of the respiratory tract. Seventy health, 3-month-old, New Zealand White rabbits, raised in 10 different rabbitries in Northern Italy were randomly selected at slaughter. No gross lesions were found at necropsy in any rabbit. In each animal, the trachea and lungs were sampled, fixed in 10% formalin, embedded in paraffin and stained with the Warthin-Starry method to evaluate the presence of CAR bacillus, and with haematoxylin and eosin to evaluate the presence of inflammatory lesions. CAR bacillus was present in 50 out of 70 rabbits (71.4%) with a prevalence of the infection that varied from 30% to 100% in the seven rabbitries. CAR bacillus was present both in the trachea and bronchi in 23 cases (32.8%), only in the trachea in 24 cases (34.3%) and only in the bronchi in three cases (4.3%). Inflammatory lesions were found in the trachea (22 cases, 31.4%) and the bronchi (58 cases, 82.8). There was a strong, statically significant correlation between the presence of CAR bacillus in the bronchi and bronchial inflammatory lesions (P < 0.0001). This study indicates that CAR bacillus infection is widespread in conventionally reared rabbits in Italy and that a possible correlation exists between the presence of CAR bacillus and bronchial inflammatory lesions.

Animals↗

Enterotoxin production in natural isolates of Bacillaceae outside the Bacillus cereus group.

Thirty-nine Bacillus strains obtained from a variety of environmental and food sources were screened by PCR for the presence of five gene targets (hblC, hblD, hblA, nheA, and nheB) in two enterotoxin operons (HBL and NHE) traditionally harbored by Bacillus cereus. Seven isolates exhibited a positive signal for at least three of the five possible targets, including Bacillus amyloliquefaciens, B. cereus, Bacillus circulans, Bacillus lentimorbis, Bacillus pasteurii, and Bacillus thuringiensis subsp. kurstaki. PCR amplicons were confirmed by restriction enzyme digest patterns compared to a positive control strain. Enterotoxin gene expression of each strain grown in a model food system (skim milk) was monitored by gene-specific reverse transcription-PCR and confirmed with the Oxoid RPLA and Tecra BDE commercial kits. Lecithinase production was noted on egg yolk-polymyxin B agar for all strains except B. lentimorbis, whereas discontinuous beta hemolysis was exhibited by all seven isolates grown on 5% sheep blood agar plates. The results of this study confirm the presence of enterotoxin genes in natural isolates of Bacillus spp. outside the B. cereus group and the ability of these strains to produce toxins in a model food system under aerated conditions at 32 degrees C.

Bacillaceae↗

Analysis of the genome of an alkaliphilic Bacillus strain from an industrial point of view.

Bacillus species and other microbes with pH optima for growth higher than pH 9 are defined as alkaliphiles. A large number of alkaliphilic Bacillus strains producing useful enzymes, have been isolated from various environments. Some of these enzymes, such as proteases and cellulases from alkaliphilic Bacillus strains, have been commercialized and have brought great advantages to industry and domestic life. To support further development of the enzyme industry, we initiated analysis of the genome of Bacillus halodurans C-125, which is 4.25Mb in size, and constructed a physical and genetic map for comparison with the Bacillus subtilis chromosome. Systematic sequencing of the whole genome of Bacillus halodurans C-125 has been automated since the beginning of May 1998, and sequencing of 98% of the whole genome has been done so far. Through genome analysis, it became apparent that the genome organization of alkaliphilic Bacillus halodurans C-125 is totally different from that of B. subtilis orthologues.

Alkalies↗