Bacterial cells spores

Apart from vegetative bacterial cells, spores can also be used as the inoculum in tests. In such cases,... 

Chlorine Dioxide. Like ozone, chlorine dioxide [10049-04-4] is a powerflil oxidant. It is usually generated as used. It has been used for disinfecting drinking water and bleaching paper pulp. Its effectiveness in killing microorganisms is well documented (305,306), and it has received recent study as a gas to sterilize medical devices. It requites 50% rh or higher to be effective. Bacterial cells had a D-value of 2.6 min and spores of 24 min (307). 

The bacterial culture converts a portion of the supplied nutrient into vegetative cells, spores, crystalline protein toxin, soluble toxins, exoenzymes, and metabolic excretion products by the time of complete sporulation of the population. Although synchronous growth is not necessary, nearly simultaneous sporulation of the entire population is desired in order to obtain a uniform product. Depending on the manner of recovery of active material for the product, it will contain the insolubles including bacterial spores, crystals, cellular debris, and residual medium ingredients plus any soluble materials which may be carried with the fluid constituents. Diluents, vehicles, stickers, and chemical protectants, as the individual formulation procedure may dictate, are then added to the harvested fermentation products. The materials are used experimentally and commercially as dusts, wettable powders, and sprayable liquid formulations. Thus, a... 

The second type of material includes spores, which may or may not produce disease symptoms but which can germinate in the insect gut and give rise to vegetative bacterial cells which in turn may produce, and exoenzymes such as phospholipases (lecithinases) or hyaluronidase. The phospholipases may produce direct toxic symptoms owing to their action on nervous or other phospholipid-containing tissue. Hyaluronidase breaks down hyaluronic acid and produces effects on animal tissue which are morphologically similar to the breakdown of insect gut wall in the presence of microbial insecticide preparations. 

It has been known for some time that certain types of bacteria spend a certain amount of their lifespan in a dormant state. The bacteria are then known as en-dospores , or just spores . In this state, they appear not to undergo any metabolic processes and are important particularly because of their heat resistance. The formation of spores is a highly complex process of bacterial cell differentiation. 

In taking this drastic action, the bacterial cells collectively desert a locale where nutrients have become scarce. Now a packet of spores, they await transportation to a new home. The wind, an animal, or perhaps flowing water will pick up the fruiting body and deposit it elsewhere. The spores of course do not guide their journey, but if by chance they land in an appropriate environment, they then revert to their free-living form. If nourishment is plentiful, they may establish a flourishing new colony of bacteria. 

Use of optical fiber biosensors for real-time detection of biowarfare agents (BWA) especially those of bacterial cells, toxins, or spores in the air, soil, or environment has been investigated by the Naval Research Laboratory (Taitt et al, 2005). In addition, many laboratories are also employing fiber optic biosensors for detection of wide varieties of foodbome pathogens, which are discussed below. 

Tetanus immunoglobulin is an example of an antibody preparation used to induee passive immunization against a mierobial toxin. Tetanus (lockjaw) is an infectious disease caused by the bacterium, Clostridium tetani. Bacterial spores can commonly contaminate surface wounds and the resulting bacterial cells produce a toxin as they multiply. The toxin interferes with normal neurological function, particularly at neuromuscular junctions. The result is spasmodic contraction of muscles and, if untreated, mortality rates are high. Treatment with antibiotics and anti-toxin, however, is highly effective if administered promptly. 

In terms of shape, the first of these are rod-shaped and are called bacilli (singular, bacillus). The bacilli often have small, whip-like structures known as flagella, with which they are able to move about. Some bacilli have oval, egg-shaped, or spherical bodies in their cells, known as spores. Under adverse conditions, such as dehydration, and in the presence of disinfectants, the bacteria may die, but the spores may be able to live on. The spores germinate when the conditions become favorable, and form new bacterial cells. Some are so resistant that they can withstand boiling and freezing temperatures and prolonged desiccation. See Fig. 1. 

A second type of bacteria is the cocci (singular, coccus) which are spherical or ovoid in shape. The individual bacterial cells of this group may occur singly [Micrococcus), in chains (Streptococcus), in pairs [Diplococcus). in irregular bunches (Staphylococcus), and in the form of cubical packets (Sarcina). The coccus does not form spores and usually is nonmotUe. See Fig. 2. 

The dye 4, 6-Diamidino-2-PhenyIindole (DAPI) in 0.001%W/V aqueous solution can be used directly on smears, ciyosections and embedded specimens to locate and count culture bacteria, without regard to their viability, in cheese and other cultured products. The dye reacts with nucleic acids by intercalation. Excitation at 360nm is best for this dye. It is worth noting two other facts about its use. DAPI cross reacts with dairy proteins, but the color of the protein-dye complex is different from that of the nucleic acid-dye complex (the latter is a steely blue/white) and so the two reactions may be discriminated. The dye also may take up to 15 minutes to enter bacterial cells, particularly spores, before fluorescence is observed. An alternative nucleic acid dye, Ethidium Bromide, has less contrast between the fluorescence induced in cells and the fluorescence of cross-reacting dairy proteins. It should be tried in other products such as meats if DAPI is not successful. 

Heat is the most widely used means of sterilization, which can be employed for both liquid medium and heatable solid objects. It can be applied as dry or moist heat (steam). The moist heat is more effective than the dry heat, because the intrinsic heat resistance of vegetative bacterial cells is greatly increased in a completely dry state. As a result the death rate is much lower for the dry cells than for moist ones. The heat conduction in dry air is also less rapid than in steam. Therefore, dry heat is used only for the sterilization of glassware or heatable solid materials. By pressurizing a vessel, the steam temperature can be increased significantly above the boiling point of water. Laboratory autoclaves are commonly operated at a steam pressure of about 30 psia, which corresponds to 121°C. Even bacterial spores are rapidly killed at 121 °C. 

Fig. 19.2. Micro-Raman spectra of different single bacterial cells normal bacterial Raman spectrum of Staph, wameri compared to Raman spectra with enhanced amounts of subcellular components calcium dipicolinate for a spore of B. pumilus polyhydroxy butyric acid (PHB) in B. megaterium cytochrome in Staph, cohnii and sarcina xanthin in M. luteus...

Beside the identification of single bacterial cell or spores by means of Raman spectroscopy, the localization of these cells inside partly complex matrices has to be performed. One approach is the combination of Raman spectroscopy, fluorescence spectroscopy and digital imaging techniques. This method was applied to detect traces of endospores and other biothreat organisms even in the presence of complex environmental matrices like bioaeroso-lic background, nasal mucin [67], or tap water [68], Another fully automated device was built to analyze bioaerosols in clean room environments, where prior to the Raman identification method a particle preselection took place [69]. 

Bacillus cereus, E. coli, and Listeria monocytogenes were separated from human blood cells. All separations were run with an AC voltage (10 Vpp at 10 kHz). Bacteria are collected at the electric field maxima by positive DEP forces and blood cells (RBC and WBC) are collected at field minima by negative DEP forces. By applying a suitable fluid flow, the blood cells are swept away, but the bacterial cells are retained [874], In another report, spores of Bacillus globigii were trapped on a DEP chip [486],... 

The different microorganisms sensitivities toward Ti02 photocatalysis follows the order virus > bacterial cell gram positive > gram negative > bacterial spores... 

The first stage in the action of an antibiotic or biocide on a bacterial cell involves interaction between the chemical and the biological entity. Adsorption of a variety of biocides into bacterial cells has been described [33] but this, per se, does not necessarily provide information about the mechanism or site of action of the antibacterial compound. However, resistant cells would usually (but not necessarily) be expected to adsorb less of a chemical than sensitive cells. In non-sporulating bacteria, changes to the outer layers of cells may follow the initial binding to the cell surface or there may be diffusion across the cell envelope in either case, an antibiotic or biocide will penetrate the cell to reach the primary site of action at the cytoplasmic membrane or within the cytoplasm. Little is known about the penetration of antibacterial agents into bacterial spores. 

Ethylene oxide (bp, 10.8°C) is a gaseous alkylating agent. It alkylates proteins and ribonucleic and deoxyribonucleic acid in micro-organisms. It replaces labile hydrogen with hydroxyethyl groups. Ethylene oxide is utilized as a surface sterilant. Bulk crystalline materials can occlude vegetative bacterial cells or spores with crystals. Consequently, ethylene oxide does not reach them. The final step prior to sterilization is an aseptic recrystallization step. 

The pathogen must be present. The stage of the pathogen that can infect a plant is technically known as inoculum. Inoculum may be a virus particle, a bacterial cell, a fungal spore or hypha. a nematode, or a seed or a piece of a parasitic plant. 

For our terahertz transmission measurements, we used solutions of thioredoxin in distilled water obtained from Sigma. The experimental and simulated signatures are correlated and dominant peaks are close in frequencies. The results of this study demonstrate that terahertz spectroscopy is a promising tool in generating spectral data for cellular components of bio agents such as bacterial cells and spores. 

A collection of airborne biological material including virus, bacterial cells, fungal spores, fragments, and byproducts of microbial metabolism. 

Like bacterial cells, unicellular eukaryotes may be subjected to widely varying environmental conditions that require extensive changes In cellular structures and function. For Instance, In starvation conditions yeast cells stop growing and form dormant spores (see Figure 1-4). In multicellular organisms, however, the environment around most cells Is relatively constant. The major purpose of gene control In us and In other complex organisms Is to tailor the properties of various cell types to the benefit of the entire animal or plant. 

Stachowiak et al. [138] coupled an automated sample preparation (ASP) system to a chip gel electrophoresis protein profiling (CGE-PP) system to execute an autonomous microfluidic sample preparation and detection of aerosolized bacterial cells and spores on the basis of protein profiling. The combined system, which was field-deployable, was capable of differentiating between bacterial organisms. It operated by collecting... 

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