Biofilm-Spore Response in Bacillus cereus and Bacillus subtilis during Nutrient Limitation

2006 ◽  
Vol 69 (5) ◽  
pp. 1168-1172 ◽  
Author(s):  
D. LINDSAY ◽  
V. S. BRÖZEL ◽  
A. VON HOLY
Keyword(s):  
Bacillus Subtilis ◽  
Bacillus Cereus ◽  
Growth Conditions ◽  
Bacillus Species ◽  
Practical Consideration ◽  
Limited Growth ◽  
Vegetative Cells ◽  
Bacillus Subtilis 168 ◽  
Standard Plate ◽  
Bacillus Spores

This study aimed to trace the dynamics of biofilm formation by vegetative cells and endospores of Bacillus cereus DL5 and Bacillus subtilis 168. Counts of B. cereus DL5 and B. subtilis 168 vegetative cells and spores either attached to glass wool or, correspondingly, planktonic cells were determined by standard plate-counting methods. Results from this study highlighted the biofilm-forming potential of both spores and vegetative cells of two different Bacillus species. It was shown that once Bacillus spores had attached to a surface, the spores germinated under favorable (B. cereus DL5) and even unfavorable (B. subtilis 168) nutrient conditions, resulting in biofilms containing both spores and vegetative populations. Furthermore, it was suggested that vegetative B. cereus DL5 cells exhibited a low propensity for spore formation in attached and planktonic growth forms in nutrient-limited growth medium. By contrast, vegetative B. subtilis 168 cells readily formed spores in planktonic and attached microcosms when exposed to nutrient-limited growth conditions. Sporulation in attached Bacillus populations is an important practical consideration for many food industries, such as dairy processing, where bacilli are routinely isolated from populations attached to processing-equipment surfaces.

UV Resonance Raman Spectra of Bacillus Spores

1992 ◽  
Vol 46 (2) ◽  
pp. 357-364 ◽  
Author(s):  
E. Ghiamati ◽  
R. Manoharan ◽  
W. H. Nelson ◽  
J. F. Sperry
Keyword(s):  
Aqueous Solutions ◽  
Bacillus Cereus ◽  
Raman Spectra ◽  
Dipicolinic Acid ◽  
Resonance Raman ◽  
Vegetative Cells ◽  
Resonance Enhancement ◽  
Uv Resonance Raman ◽  
Bacillus Spores ◽  
Resonance Raman Spectra

UV resonance Raman spectra of Bacillus cereus, Bacillus megaterium, and Bacillus subtilis endospores have been excited at 222.7,230.7,242.5, and 251.1 nm, and spectra have been compared with those of vegetative cells. The resonance Raman spectra of aqueous solutions of dipicolinic acid and calcium dipicolinate have been measured at the same wavelengths. Spectra of endospores and their corresponding germinated spores show only modest differences when excited at 222, 231, and 251 nm. However, very substantial differences appear when excitation occurs at 242 nm. Difference spectra obtained at 242 nm by subtracting spectra of germinated spores of Bacillus cereus from spectra of their corresponding endospores are attributed almost entirely to dipicolinate. Vegetative cells and endospores show large spectral dissimilarities at all exciting wavelengths. These spectral differences, which vary strongly with exciting wavelength, appear to be the result of large differences in the amounts and composition of proteins and nucleic acids, especially ribosomal RNA. The very substantial resonance enhancement of Raman spectra has been obtained from aqueous solutions of pure dipicolinic acid and of sodium and calcium dipicolinate salts, as well as spores at the various exciting wavelengths. The strong enhancement of dipicolinate spectra in spores, however, was noted only with 242-nm excitation. Consequently, only with 242-nm light was it possible to selectively and sensitively excite and study calcium dipicolinate in spores. Resonance enhancement of the dipicolinate spectra with 242-nm excitation appears due primarily to resonance interactions with n-π* electronic transitions associated with the pyridine ring and/or the carboxylate group.

Application of Nisin and Pediocin against Resistance and Germination of Bacillus Spores in Sous Vide Products

2009 ◽  
Vol 72 (3) ◽  
pp. 515-523 ◽  
Author(s):  
M. L. CABO ◽  
B. TORRES ◽  
J. J. R. HERRERA ◽  
M. BERNÁRDEZ ◽  
L. PASTORIZA
Keyword(s):  
Vegetative State ◽  
Bacillus Species ◽  
Processed Foods ◽  
Positive Interaction ◽  
Minimally Processed ◽  
Vegetative Cells ◽  
Additional Challenge ◽  
Bacillus Spores ◽  
Sous Vide ◽  
High Concentrations

Sous vide and other mild preservation techniques are increasingly demanded by consumers. However, spores often will survive in minimally processed foods, causing both spoilage and safety problems. The main objective of the present work was to solve an industrial spoilage problem associated with two sous vide products: mushrooms and shellfish salad. Bacillus subtilis and Bacillus licheniformis predominated as the most heat-resistant organisms isolated from mushrooms and shellfish salad, respectively. The combined effects of nisin and pediocin against resistance and germination of both Bacillus species were described by empirical equations. Whereas nisin was more effective for decreasing thermal resistance of B. subtilis spores, pediocin was more effective against B. licheniformis. However, a significant positive interaction between both biopeptides for decreasing the proportion of vegetative cells resulting from thermoresistant spores was demonstrated in later experiments, thus indicating the increased efficacy of applying high concentrations of both bacteriocins. This efficacy was further demonstrated in additional challenge studies carried out at 15°C in the two sous vide products: mushrooms and shellfish salad. Whereas no vegetative cells were detected after 90 days in the presence of bacteriocins, almost 100% of the population in nontreated samples of mushrooms and shellfish salad was in the vegetative state after 17 and 43 days of storage at 15°C, respectively.

scholarly journals The wall content and composition of Bacillus subtilis var. niger grown in a chemostat

1970 ◽  
Vol 118 (3) ◽  
pp. 367-373 ◽  
Author(s):  
D. C. Ellwood
Keyword(s):  
Bacillus Subtilis ◽  
Phosphorus Content ◽  
Teichoic Acid ◽  
Dry Weight ◽  
Growth Conditions ◽  
Glycerol Phosphate ◽  
Limited Growth ◽  
Anionic Polymer ◽  
Rate Analysis ◽  
Teichuronic Acid

Bacillus subtilis var. niger was grown in a chemostat with various growth limitations and at various growth rates. The wall content and composition of the organism grown under these conditions were determined. The wall content, expressed as a percentage of the dry weight of organisms, varied with the growth rate. Analysis of wall samples showed that their composition also varied, particularly with respect to the phosphorus content. Wall samples extracted with trichloroacetic acid under carefully controlled conditions were found to contain various amounts of phosphorus, this being present as a glycerol phosphate polymer containing hexose (glucose and in some cases galactose), i.e. a teichoic aid. Teichoic acids were present in the walls of organisms grown under all conditions except when phosphorus limited growth. Then a different anionic polymer, composed of glucuronic acid and N-acetylgalactosamine (a teichuronic acid), was present. Under the specific growth conditions at pH7.0 and 35°C in a chemostat, teichoic acid and teichuronic acid appeared to be mutually exclusive.

DETECTION AND DIFFERENTIATION OF SPORE AND VEGETATIVE FORMS OF BACILLUS SPP. USING INFRARED SPECTROSCOPIC METHODS

2008 ◽  
Vol 18 (02) ◽  
pp. 417-427
Author(s):  
DIANE ST. AMANT ◽  
MARK CAMPBELL ◽  
ANDREW BECK ◽  
LESLIE WILLIAMS ◽  
JENNIFER MINTER ◽  
...  
Keyword(s):  
Thin Film ◽  
Infrared Spectroscopy ◽  
Attenuated Total Reflection ◽  
Bacillus Species ◽  
Infrared Spectrometry ◽  
Limited Information ◽  
Transmission Method ◽  
Vegetative Cells ◽  
Bacillus Spp ◽  
Bacillus Spores

Infrared spectroscopy has been demonstrated as a powerful tool for taxonomic classification of bacteria when the microbes are grown and sampled under carefully controlled conditions. Infrared spectroscopy affords limited information about relative proportions of certain chemical functional groups in whole microbial cells. The objective of this work is to elucidate the ability of infrared spectroscopy to identify and speciate Bacillus spp. regardless of sample history. Spectrometers utilize different scanning methods to collect infrared absorption spectra. We employed three; transmission through a thin film, transmission infrared microscopy, and Attenuated Total Reflection (ATR). Target organisms include Bacillus anthracis, and several near neighbors. Each strain was cultured at 24°C and 35°C on three solid media. Microorganisms were incubated for up to ten days to include vegetative cells, spore formation and mature spores. Triplicate microbe samples were prepared and analyzed according to instrument requirements using the three measurement modes. Triplicate samples of BSL-3 organisms were analyzed only by the thin film transmission method. Spectral data was analyzed using the cluster analysis function of OPUS software. We report that infrared spectrometry is capable of discerning Bacillus spores from vegetative cells and the phylogenic clustering of Bacillus species according to pathogenicity levels via infrared spectral analysis.

scholarly journals Bacillus subtilis 168 Contains Two Differentially Regulated Genes Encoding l-Asparaginase

2002 ◽  
Vol 184 (8) ◽  
pp. 2148-2154 ◽  
Author(s):  
Susan H. Fisher ◽  
Lewis V. Wray
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Mutational Analysis ◽  
Limited Growth ◽  
Mobility Shift ◽  
Regulatory Factors ◽  
Bacillus Subtilis 168 ◽  
Dnase I Footprinting ◽  
Genes Encoding ◽  
Gel Mobility Shift

ABSTRACT Expression of the two Bacillus subtilis genes encoding l-asparaginase is controlled by independent regulatory factors. The ansZ gene (formerly yccC) was shown by mutational analysis to encode a functional l-asparaginase, the expression of which is activated during nitrogen-limited growth by the TnrA transcription factor. Gel mobility shift and DNase I footprinting experiments indicate that TnrA regulates ansZ expression by binding to a DNA site located upstream of the ansZ promoter. The expression of the ansA gene, which encodes the second l-asparaginase, was found to be induced by asparagine. The ansA repressor, AnsR, was shown to negatively regulate its own expression.

Enumeration of Bacillus and Bacillus cereus Spores in Food from Spain

1989 ◽  
Vol 52 (3) ◽  
pp. 184-188 ◽  
Author(s):  
Mªs ANGELES MOSSO ◽  
Mª LUISA GARCÍA ARRIBAS ◽  
JOSÉ A. CUENA ◽  
Mª CARMEN DE LA ROSA
Keyword(s):  
Bacillus Cereus ◽  
Vascular Permeability ◽  
Type Strain ◽  
Biochemical Properties ◽  
Bacillus Species ◽  
Contamination Rate ◽  
Retail Markets ◽  
Milk Products ◽  
Salad Dressing ◽  
Bacillus Spores

The Bacillus and B. cereus spore populations of 102 samples of food (salad dressing, dried soups, sweet desserts, milk and milk products, rice dishes, pasta and flour), 93 collected from retail markets of Madrid and 9 from chinese restaurants have been studied. Bacillus spores were detected in 82.4% of the samples, while the incidence of B. cereus spores was 14.7%. In salad dressing and dried soups the contamination rate by species of Bacillus was 100% and also both showed the highest contamination of B. cereus spores (25% and 50% respectively). No samples of rice dishes and pasta exhibited B. cereus spore contamination although these were contaminated by other Bacillus species. All the samples studies showed less than 104 and 105 c.f.u./g or ml B. cereus and Bacillus spores respectively. Twenty-four strains of B. cereus isolated were characterized by morphology and biochemical properties and showed most of the characteristics of the type strain. Enterotoxin, phospholipase C and hemolysin production were present in 13 of the isolated strains showing different degrees of production. The vascular permeability reaction (VPR) was used for determining enterotoxin activity. The enterotoxigenic strains showed a positive VPR; 6 of them caused necrosis and 12 positive mouse lethal tests.

The possible involvement of trypsin-like enzymes in germination of spores of Bacillus cereus T and Bacillus subtilis 168

1991 ◽  
Vol 137 (5) ◽  
pp. 1145-1153 ◽  
Author(s):  
H. Boschwitz ◽  
L. Gofshtein-Gandman ◽  
H. O. Halvorson ◽  
A. Keynan ◽  
Y. Milner
Keyword(s):  
Bacillus Subtilis ◽  
Bacillus Cereus ◽  
Bacillus Subtilis 168
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