Microbiological applications

A similar EMS study was performed on Co in thermophilic cyanobacteria (blue-green alga, Synechococcus vulcanus) i ncubated with carrier-free salt for 4 months at 55 °C [29]. The cell suspension v/as centrifuged, and live cells were 

In the soil diazotrophic rhizobacterium A. brasilense (strain Sp245, reported to be tolerant to submillimolar concentrations of heavy metals, including cobalt(ll), in the culture medium [32]), EMS studies were first performed on freeze-dried bacterial samples (measured at T = 80K Fig. 17.2) [27]. The following experiments with the same bacteria were performed with live cells rapidly frozen after certain periods of time (2-60 min) of contact with Co , and EMS spectra were measured for frozen suspensions (without drying), which more closely represent the state of cobalt in the live cells [31,32] (Fig. 17.3). Mossbauer parameters calculated from the experimental data are listed in Table 17.1. 

Emission Mossbauer spectra of dried cells of Azospirillum brasilense (strain Sp245) that were incubated as live cells with CoCl2 for 2 min (a) and 60 min (b) at ambient temperature, then rapidly frozen in liquid nitrogen and freeze-dried prior to EMS measurements (spectra measured at 7=80 K see also Table 17.1). The positions of spectral components (quadrupole doublets) composing the whole spectrum (solid envelope), obtained by fitting the experimental data (points), are shown above the spectra with square brackets the same for other figures with emission spectra. (Adapted from Ref. 27.) 

For each of the aforementioned cell samples, there were two EMS components corresponding to two chemical forms of high-spin Co . (The presence of the third component with the parameters typical for high-spin nucleogenic iron(lll), stabilized after nuclear decay of the parent Co + ion, is evidently a result of aftereffects of the Co Fe nuclear transformation, as Co is not expected to appear in such systems.) The presence of at least two major cobaltous forms (with different 5 and A q values, see Table 17.1) revealed in the spectra of cells maybe related to the availability of different functional groups (also with possibly different donor atoms) as ligands at the bacterial cell surface (see, for example. Refs 31,32 and references therein). 

In Fig. 17.4, the Mossbauer parameters are plotted for different cobalt(ll) forms in each sample and for various periods of contact (2 and 60 min) of the live bacteria with Co , as well as for dead bacterial cells (thermally killed by storing in the medium at 95 °C in a water bath) and for the cell-free supernatant liquid [5,31]. The EMS data for different periods (2 min and I h) of contact of live bacteria with Co + traces essentially differed in the corresponding QS values (see Table 17.1) for the two (+2) forms [31 ]. This finding indicated that within an hour, after primary rapid adsorption onto the cell surface, cobalt(ll) underwent further transformation, most probably occurring within the cell membrane. Nevertheless, the parameters for live bacteria after 2 min and for dead bacteria were found to be rather close (essentially 

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For PyMS to be used for (1) routine identification of microorganisms and (2) in combination with ANNs for quantitative microbiological applications, new spectra must be comparable with those previously collected and held in a data base.127 Recent work within our laboratory has demonstrated that this problem may be overcome by the use of ANNs to correct for instrumental drift. By calibrating with standards common to both data sets, ANN models created using previously collected data gave accurate estimates of determi-nand concentrations, or bacterial identities, from newly acquired spectra.127 In this approach calibration samples were included in each of the two runs, and ANNs were set up in which the inputs were the 150 new calibration masses while the outputs were the 150 old calibration masses. These associative nets could then by used to transform data acquired on that one day to data acquired at an earlier data. For the first time PyMS was used to acquire spectra that were comparable with those previously collected and held in a database. In a further study this neural network transformation procedure was extended to allow comparison between spectra, previously collected on one machine, with spectra later collected on a different machine 129 thus calibration transfer by ANNs was affected. Wilkes and colleagues130 have also used this strategy to compensate for differences in culture conditions to construct robust microbial mass spectral databases. 

Benson, H. J., Microbiological Applications A Laboratory Manual in General Microbiology (4th ed.). Dubuque, IA Wm. C. Brown Publishers, 1985. 

Several commercially available preformulated agar media serve as the basis for much of the laboratory work discussed in the book. Unless one wishes to prepare growth media from scratch using raw materials, those identified in Table A-2 appear to be a required cost. Premade and poured media is also available from major supply houses. However, these are generally marketed for medical microbiological applications. Commercial winery laboratories may market premade/poured media. 

Marshall, C.R. and V.T. Walkley. 1951. Some aspects of microbiology applicable to commercial apple juice production. I. Distribution of microorganisms on fruit. Food Res. 16 448-456. 

Py-MS is commonly applied for bacterial fingerprinting, i.e. classification of characteristic signal patterns followed the first reports published in the 1960s on the applicability of analytical pyrolysis techniques to clinical and pharmaceutical microbiology. Application of Py-MS as an independent tool for the char-... 

The chemical engineer is concerned with the industrial application of processes. This involves the chemical and microbiological conversion of material with the transport of mass, heat and momentum. These processes are scale-dependent (i.e., they may behave differently in small and large-scale systems) and include heterogeneous chemical reactions and most unit operations. Tlie heterogeneous chemical reactions (liquid-liquid, liquid-gas, liquid-solid, gas-solid, solid-solid) generate or consume a considerable amount of heat. However, the course of... 

For food and drink, medical, pharmaceuticals and cosmetics production the microbiological quality of the water becomes paramount. Even in applications where biological quality is not directly important, uncontrolled growth can be a damaging nuisance. Warm-water systems and cooling circuits in particular are a potential hazard (e.g. from Legionella). Some water treatment or conditioning is commonly required. 

Gravimetric, photometric, chromatographic, enzymatic, and microbiological methods for the determination of amino acids are reviewed and discussed. Marked advances have been made during the present decade in methods applicable to the determination of amino acids, and with the development of new analytical methods it should soon be possible to determine all the amino acids of biological importance with a degree of accuracy sufficient for practical as well as many theoretical purposes. 

In more recent times chemically defined basal media have been elaborated, on which the growth of various lactic acid bacteria is luxuriant and acid production is near-optimal. The proportions of the nutrients in the basal media have been determined which induce maximum sensitivity of the organisms for the test substance and minimize the stimulatory or inhibitory action of other nutrilites introduced with the test sample. Assay conditions have been provided which permit the attainment of satisfactory precision and accuracy in the determination of amino acids. Experimental techniques have been provided which facilitate the microbiological determination of amino acids. On the whole, microbiological procedures now available for the determination of all the amino acids except hydroxy-proline are convenient, reasonably accurate, and applicable to the assay of purified proteins, food, blood, urine, plant products, and other types of biological materials. On the other hand, it is improbable that any microbiological procedure approaches perfection and it is to be expected that old methods will be improved and new ones proposed by the many investigators interested in this problem. 

Odham, G., Larsson, L., and Mardh, P. A., Eds. Gas Chromatography/Mass Spectrometry Applications in Microbiology. New York Plenum Press, 1984. 

Verbeken, D. Dierckx, S. Dewettinck. (2003). Exudate gums Occurrence, production, and applications. Applied Microbiology and Biotechnology, Vol.63, No. 1, (November 2003), pp. 10-21, ISSN 0175-7598. 

Bisphenols are composed of two phenolic groups connected by various linkages. Hydroxy halogenated derivatives, such as hexachlorophane (Fig. 10.7D) and triclosan, are the most active microbiologically, but are bacteriostatic at use-concentrations and have little antipseudomonal activity. The use of hexachlorophane is also limited by its serious toxicity. Both hexachlorophane and trichlosan have limited application in medicated soaps and washing creams. 

Denyer S.P. (1990) Monitoring microbiological quality application of rapid microbiological methods to pharmaceuticals. In Guide to Microbiological Control in Pharmaceuticals (eds S.P. Denyer R.M. Baird), pp. 146-156. Chichester Ellis Horwood. 

A sterilization process may thus be developed without a full microbiological background to the product, instead being based on the ability to deal with a worst case condition. This is indeed the situation for official sterilization methods which must be capable of general application, and modem pharmacopoeial recommendations are derived firm a careful analysis of experimental data on bacterial spore survival following treatments with heat, ionizing radiation or gas. 

There is an apparent anomaly in that it also states that the preferred combination of temperature and time is a minimum of 121 °C maintained for 15 minutes, which, by definition, equates to an Fq value of 15. The latter, however, is applicable where the material to be sterilized may contain relatively large numbers of thermophilic bacterial spores, and an Fq of 8 is appropriate for a microbiologically validated process where the bioburden is low and the spores likely to be present are those of (the generally more heat sensitive) mesophilic species. 

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