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At least 19 recordsLinked to original sources
PubMed2000

Control of bacterial spores.

Bacterial spores are much more resistant than their vegetative counterparts. The most dangerous spore-former is Clostridium botulinum which produces a potent neurotoxin that can prove fatal. The most common food poisoning from a spore-former is caused by C. perfringens. Other food poisoning spore-formers include Bacillus cereus, B. subtilis and B. licheniformis. There are a number of non-pathogenic spore-formers including butyric and thermophilic anaerobes that cause significant economic losses to food producers. Some unusual spoilage complaints have been reported, for example, B. sporothermodurans in UHT milk, Alicyclobacillus acidoterrestris in apple and orange juice and Desulfotomaculum nigrificans in hot vending machines. Control of spore-formers requires an understanding of both the resistance and outgrowth characteristics of the spores.

Bacterial Infections↗
PubMed2004

Structure of the DNA-SspC complex: implications for DNA packaging, protection, and repair in bacterial spores.

Bacterial spores have long been recognized as the sturdiest known life forms on earth, revealing extraordinary resistance to a broad range of environmental assaults. A family of highly conserved spore-specific DNA-binding proteins, termed alpha/beta-type small, acid-soluble spore proteins (SASP), plays a major role in mediating spore resistance. The mechanism by which these proteins exert their protective activity remains poorly understood, in part due to the lack of structural data on the DNA-SASP complex. By using cryoelectron microscopy, we have determined the structure of the helical complex formed between DNA and SspC, a characteristic member of the alpha/beta-type SASP family. The protein is found to fully coat the DNA, forming distinct protruding domains, and to modify DNA structure such that it adopts a 3.2-nm pitch. The protruding SspC motifs allow for interdigitation of adjacent DNA-SspC filaments into a tightly packed assembly of nucleoprotein helices. By effectively sequestering DNA molecules, this dense assembly of filaments is proposed to enhance and complement DNA protection obtained by DNA saturation with the alpha/beta-type SASP.

Bacillus subtilis↗
PubMed1993

Dipicolinic Acid Greatly Enhances Production of Spore Photoproduct in Bacterial Spores upon UV Irradiation.

Formation of the spore photoproduct (SP) (5-thyminyl-5,6-dihydrothymine) in DNA of dormant spores of Bacillus subtilis upon UV irradiation is due to binding of alpha/beta-type small, acid-soluble proteins (SASP). However, the yield of SP as a function of UV fluence is approximately 15-fold higher in spores than in an alpha/beta-type-SASP-DNA complex in vitro. The yield of SP as a function of UV fluence in forespore DNA from mutants which make alpha/beta-type SASP but not dipicolinic acid (DPA) was 10 to 20 times lower than that in dormant spores. Furthermore, the yield of SP as a function of UV fluence in an alpha/beta-type-SASP-DNA complex in vitro was increased sixfold by DPA. These data provide further support for the idea that the high DPA level in dormant spores increases the yield of SP as a function of UV fluence and thereby sensitizes spores to UV.

Journal Article↗
PubMed2006

Effect of the wavelength of infrared heaters on the inactivation of bacterial spores at various water activities.

Bacterial spores (Bacillus subtilis subsp. subtilis NBRC 16183) inoculated onto a stainless steel Petri dish and treated at nine levels of water activity (a(w)) for 2 days were inactivated by infrared radiation heating (IRH) using three kinds of infrared heaters with different radiation spectra. The peak wavelengths used were 950, 1,100 and 1,150 nm. In general, the inactivating efficacy of IRH treatment against bacterial spores with shorter wavelength heater (950 nm) was greater than that with other heaters. The decimal reduction times (D value) calculated using the linear portion of survival curves were affected by both the initial a(w) values and the spectra of the infrared rays. Spores at approximately 0.9, 0.7 and 0.6 a(w) were most resistant to IRH at wavelengths of 950, 1,100 and 1,150 nm, respectively. The a(w) values that led to maximum D values for bacterial spores increased as the wavelength was shortened. Optimum a(w) values were identified for the inactivation of bacterial spores by IRH. Spore resistance to IRH could also be affected by the spectral characteristics of the infrared absorption, which varied with the a(w) of bacterial spores.

Bacillus subtilis↗
PubMed2002

FAST CARS: engineering a laser spectroscopic technique for rapid identification of bacterial spores.

Airborne contaminants, e.g., bacterial spores, are usually analyzed by time-consuming microscopic, chemical, and biological assays. Current research into real-time laser spectroscopic detectors of such contaminants is based on e.g., resonance fluorescence. The present approach derives from recent experiments in which atoms and molecules are prepared by one (or more) coherent laser(s) and probed by another set of lasers. However, generating and using maximally coherent oscillation in macromolecules having an enormous number of degrees of freedom is challenging. In particular, the short dephasing times and rapid internal conversion rates are major obstacles. However, adiabatic fast passage techniques and the ability to generate combs of phase-coherent femtosecond pulses provide tools for the generation and utilization of maximal quantum coherence in large molecules and biopolymers. We call this technique FAST CARS (femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman spectroscopy), and the present article proposes and analyses ways in which it could be used to rapidly identify preselected molecules in real time.

Kinetics↗
PubMed2003

Emerging Applications of Bacterial Spores in Nanobiotechnology.

Bacterial spores are robust and dormant life forms with formidable resistance properties, in part, attributable to the multiple layers of protein that encase the spore in a protective and flexible shield. The coat has a number of features pertinent to the emerging field of nanobiotechnology including self-assembling protomers and the capacity for engineering and delivery of foreign molecules. This review gives an account of recent progress describing the use of the spore, and specifically, the spore coat as a vehicle for heterologous antigen presentation and protective immunization (vaccination). As interest in the spore coat increases it seems likely that they will be exploited further for drug and enzyme delivery as well as a source of novel self-assembling proteins.

Journal Article↗
PubMed1984

Detection and enumeration of injured bacterial spores in processed foods.

Injury of bacterial spores is manifested in ways similar to those for vegetative cells, i.e. altered nutritional requirements, increased sensitivity to inhibitors and modified optimum temperatures. However, injury in spores may involve activation, germination and/or outgrowth systems, in addition to the vegetative growth processes. Food processes in the form of heat, acid, inhibitors, preservatives, low water activity and combinations of these factors can stress spores. Consequently, detection and enumeration methods designed to recover bacterial spores from processed foods must always consider the requirements of injured spores. Injury to germination systems has been circumvented through the addition of non-nutritive agents, such as lysozyme, to recovery media, or by incubation at an alternative temperature which favours a secondary germination system. A shift in temperature has also permitted repair of damaged outgrowth systems. Addition of materials such as starch and charcoal can reduce the sensitivity of injured spores to some inhibitors. Our current research on hypochlorite injury of Cl. botulinum, differing injury responses for B. cereus in rice and TSB, and injury of B. cereus earlier in the heating process at 85 degrees C than at 90 degrees C indicate a need for more information on the injury of spores in processed foods.

Bacteria↗
PubMed1990

Bacterial spores and chemical sporicidal agents.

Bacterial spores are among the most resistant of all living cells to biocides, although the response depends on the stage of sporulation. The development of resistance to some agents such as chlorhexidine occurs much earlier in sporulation than does resistance to glutaraldehyde, which is a very late event. During germination or outgrowth or both, resistance is lost and the cells become as susceptible to biocides as nonsporulating bacteria. Mechanisms of spore resistance to, and the action of, biocides are discussed, and possible means of enhancing antispore activity are considered. The clinical and other uses of sporicidal and sporostatic chemical agents are described.

Disinfectants↗
PubMed1968

Mixed chelates of Ca(II)-pyridine-2,6-dicarboxylate with some amino acids related to bacterial spores.

The high resistance of bacterial spores to heat has been repeatedly postulated to be due to stabilization of spore biopolymers by metal chelate compounds. Binding of calcium dipicolinic acid (Ca(II)-DPA) with spore proteins and amino acids has been discussed in the literature, but equilibrium data are generally lacking. By means of potentiometric pH titrations at 25 degrees C and an ionic strength of 1.0 (KNO(3)), the formation of Ca(II)-DPA (1:1 and 1:2) chelates and the interactions of Ca(II)-DPA chelate with a mole of each of three typical amino acids viz., cysteine, alanine, and glycine has been investigated. Analysis of the potentiometric data indicates that calcium and DPA forms 1:1 and 1:2 chelates with log K(ML1) = 4.39 +/- 0.01 and log K(ML2) = 2.25 +/- 0.01. In the presence of an equimolar amount of each of the amino acids under consideration, the Ca(II)-DPA chelate forms mixed ligand (ternary) chelate yielding the following stepwise stability constants: log K(1) = 4.17 +/- 0.01, log K(2) = 0.78 +/- 0.01 for cysteine, log K(1) = 4.06 +/- 0.01, log K(2) = 0.65 +/- 0.01 for alanine, and log K(1) = 4.30 +/- 0.02, log K(2) = 0.11 +/- 0.01 for glycine. Methods for calculating the stability constants of the mixed ligand system have been developed. On the basis of the potentiometric equilibrium data, possible structures for the various calcium chelate species are discussed. The data suggest that the differences in heat resistance of various strains of bacterial spores may conceivably be related to the differences in composition and stability of coordination complexes in the spore.

Alanine↗
PubMed2002

Flash detection/identification of pathogens, bacterial spores and bioterrorism agent biomarkers from clinical and environmental matrices.

We propose to develop an integrated rapid, semiportable, prototype point microbial detection/identification system for clinical specimens that is also capable of differentiating microbial bioterrorism attacks from threats or hoaxes by defining the pathogen. The system utilizes "flash" extraction/analytical system capable of detection/identification of microbes from environmental and clinical matrices. The system couples demonstrated technologies to provide quantitative analysis of lipid biomarkers of microbes including spores in a system with near-single cell (amol/microl) sensitivity. Tandem mass spectrometry increases specificity by providing the molecular structure of neutral lipids, phospholipids, and derivatized spore-specific bacterial biomarker, 2,6-dipicolinic acid (DPA) as well as the lipopolysaccharide-amide-linked hydroxy-fatty acids (LPS-ALHFA) of Gram-negative bacteria. The extraction should take about an hour for each sample but multiple samples can be processed simultaneously.

Bacteria↗
PubMed2003

Near-infrared surface-enhanced-Raman-scattering-mediated detection of single optically trapped bacterial spores.

A novel methodology has been developed for the investigation of bacterial spores. Specifically, this method has been used to probe the spore coat composition of two different Bacillus stearothermophilus variants. This technique may be useful in many applications; most notably, development of novel detection schemes toward potentially harmful bacteria. This method would also be useful as an ancillary environmental monitoring system where sterility is of importance (i.e., food preparation areas as well as invasive and minimally invasive medical applications). This unique detection scheme is based on the near-infrared (NIR) surface-enhanced Raman scattering (SERS) from single, optically trapped, bacterial spores. The SERS spectra of bacterial spores in aqueous media have been measured using SERS substrates based on approximately 60-nm-diameter gold colloids bound to 3-aminopropyltriethoxysilane derivatized glass. The light from a 787-nm laser diode was used to trap and manipulate as well as simultaneously excite the SERS of an individual bacterial spore. The collected SERS spectra were examined for uniqueness and the applicability of this technique for the strain discrimination of Bacillus stearothermophilus spores. Comparison of normal Raman and SERS spectra reveals not only an enhancement of the normal Raman spectral features but also the appearance of spectral features absent in the normal Raman spectrum.

Cells, Immobilized↗
PubMed2005

Autofluorescence as a viability marker for detection of bacterial spores.

Recent biological terrorism events have indicated that bacterial spores such as Bacillus anthracis are real threat agents. Real time detection of biological agents is possible with the use of an ultraviolet Fluorescent Aerodynamic Particle Sizer (FLAPS) that measures particles' intrinsic fluorescence. It is important to know whether intrinsic fluorescence could be used to estimate agents' viability. Two categories of Bacillus spore populations can be differentiated by the intensity of intrinsic fluorescence emitted by ultraviolet (UV) stimulation : autofluorescent and non-autofluorescent. This study was performed to determine whether intensity of autofluorescence correlates with spore viability. Spores were analyzed using flow cytometer (equipped with a cell sorter) to mimic optical properties of FLAPS. Autofluorescent and non-autofluorescent spores were sorted according to the intensity of autofluorescence emitted following UV stimulation. Culturability, membrane integrity, membrane potential and dipicolinic acid (DPA) content were assessed. Autofluorescent spores were 1.7 times more culturable than the corresponding non-autofluorescent population. Moreover, a small proportion of autofluorescent spores exhibited extracellular membrane damages. Autofluorescent spores also showed higher membrane potential activity and contained higher levels of DPA. In conclusion, this study documents that the overall viability potential of bacterial spores can be assessed by UV flow cytometry used in the FLAPS technology.

Bacillus anthracis↗
PubMed2004

Applied and ecological aspects of oxidative-stress damage to bacterial spores and to oral microbes.

Bacterial cells have adapted in a variety of ways to resist oxidative stresses and damage in their everyday lives in a predominantly aerobic world. The nearly universal occurrence of resistance mechanisms against oxidative stresses, particularly those due to reactive oxygen species (ROS), suggests that most, if not all, bacteria have to deal with oxidative assaults. A primary source of oxidative stress is aerobic metabolism, which leads to production of ROS such as hydrogen peroxide, superoxide radical, perhydroxyl radical, hydroxyl radical and a variety of other toxic metabolites, including organic peroxides and other organics or inorganics able to transfer electrons to sites of oxidative damage. Anaerobes as well as aerobic and facultative organisms are subject to oxidative stresses, often as a result of their own metabolism of O2 or that of associated facultative organisms. If anaerobes would just ignore oxygen instead of metabolizing it, they would not have to deal with toxic metabolites of their own making. Another major source of oxidative stress comes from the use of oxidative agents in the disinfection-sterilization industry. Notable examples are hypochlorite for water purification and hydrogen peroxide used for industrial sterilization. Antimicrobials such as isoniazide and mitomycin C also act oxidatively to cause damage. In this article, aseptic packaging and processing involving use of hydrogen peroxide for sterilization of packaging materials is reviewed as an example of oxidative stress imposed on bacterial spores and vegetative cells from outside the organisms or the microbial community. The other example considered is related to oral microbiology and infectious disease in which oxidative stress may arise from the metabolism of the oral microbiota or may come from outside through use of oral care products.

Bacterial Physiological Phenomena↗
PubMed2005

Formation of the spore clumps during heat treatment increases the heat resistance of bacterial spores.

Effects of the clumping of bacterial spores on their heat resistance as a result of heat treatment were investigated. Spore suspensions of Bacillus cereus, Bacillus coagulans and Bacillus licheniformis were heated at 85 degrees C. Survivor curves of the three strains showed tailing in all treatments after 30 min. As the treatment time increased, the formation of spore clumps increased in all strains after 20 min. Relative hydrophobicity of the spore surface increased as a result of heat treatment. The effect of spore concentration on the inactivation of the B. licheniformis spores was investigated, and surviving curves showed no tailing below a concentration of 4.9 log CFU/ml.

Bacillus↗
PubMed2003

Bacterial spores as heat stable vaccine vehicles.

Recently, the first use of bacterial spores as vaccine vehicles was reported, showing that mice orally immunised with Bacillus subtilis spores expressing a tetanus antigen could be protected against lethal challenge with tetanus toxin. Unlike many second generation vaccine systems currently under development, none offer the heat stability of bacterial spores or the flexibility for genetic manipulation. The current use of Bacillus spores as probiotics for both humans and animals may facilitate their eventual licensing as oral vaccines. This review reports the progress that has been made in the establishment of bacterial spores as vaccine vehicles and outlines the potential advantages of the spore vaccine approach.

Administration, Oral↗
PubMed2003

Bacterial spores as vaccine vehicles.

For the first time, bacterial spores have been evaluated as vaccine vehicles. Bacillus subtilis spores displaying the tetanus toxin fragment C (TTFC) antigen were used for oral and intranasal immunization and were shown to generate mucosal and systemic responses in a murine model. TTFC-specific immunoglobulin G titers in serum (determined by enzyme-linked immunosorbent assay) reached significant levels 33 days after oral dosing, while responses against the spore coat proteins were relatively low. Tetanus antitoxin levels were sufficient to protect against an otherwise lethal challenge of tetanus toxin (20 50% lethal doses). The robustness and long-term storage properties of bacterial spores, coupled with simplified genetic manipulation and cost-effective manufacturing, make them particularly attractive vehicles for oral and intranasal vaccination.

Animals↗