Culturing techniques

Economic evaluations of algal production indicate that production costs vary from 0.15 to 4.00/kg of algal product, depending on type of bioreactor, culture technique, and operating conditions (51). For systems with controlled agitation and carbonation, including raceways and tubular reactors, production costs ate estimated to range from 2.00 to 4.00/kg. 

It is necessary to estabUsh a criterion for microbial death when considering a sterilization process. With respect to the individual cell, the irreversible cessation of all vital functions such as growth, reproduction, and in the case of vimses, inabiUty to attach and infect, is a most suitable criterion. On a practical level, it is necessary to estabUsh test criteria that permit a conclusion without having to observe individual microbial cells. The failure to reproduce in a suitable medium after incubation at optimum conditions for some acceptable time period is traditionally accepted as satisfactory proof of microbial death and, consequentiy, stetihty. The appHcation of such a testing method is, for practical purposes, however, not considered possible. The cultured article caimot be retrieved for subsequent use and the size of many items totally precludes practical culturing techniques. In order to design acceptable test procedures, the kinetics and thermodynamics of the sterilization process must be understood. 

During the early 1900s, vaccines against major human epidemic diseases such as pertussis, diphtheria, tetanus, and tuberculosis were developed. Vaccines for many animal diseases were also available. In the early 1950s, the development of cell culture techniques byj. E. Enders at Harvard was followed by another series of major advances in vaccine development. Vaccines against poHo, mumps, measles, and mbeUa were Hcensed during the 1960s. 

The surface culture technique is undoubtedly easier to perform and cheaper to install. The restricted volumes of die system are, however, a disadvantage. 

The first culture technique, reported in 1927, to be attempted commercially was a surface-culture, shallow-pan technique, though this method has not been used for many years. Relatively soon after this, in 1933, production using a submerged culture technique was reported and this method has been in use continuously since then. Various significant developments have been made, notably the addition of caldum carbonate to neutralise the adds produced in order to increase yields (1937) and the use of sodium hydroxide for neutralisation (1952). 

The mold isolated by Alexander Fleming in early 1940s was Penicillium notatum, who noted that this species killed his culture of Staphylococcus aureus. The production of penicillin is now done by a better penicillin-producing mould species, Penicillium chryso-genum. Development of submerged culture techniques enhanced the cultivation of the mould in large-scale operation by using a sterile air supply. 

Various assay methods have been used to detect the presence of inhibitory substances. These include some of the classical tests used by investigators of growth-promoting substances—i.e., the various Avena coleoptile assays which utilize intact, decapitated, or isolated cylinders and the split pea stem test. Effects on seed germination and seedling shoot or root growth and development have also been measured in addition to other visible expressions of inhibition. Details of many of these tests have been compiled by Mitchell et al. (99). Tests have been carried out in Petri dishes, with various solution culture techniques, and by sand and soil culture. Effects so measured may or may not be similar to those obtained under field situations— i.e., the establishment of inhibition under controlled conditions pro-... 

Stavarek, S.J. Rains, D.W. (19846) Cell culture techniques Selection and physiological studies of salt tolerance. In Salinity Tolerance in Plants Strategies for Crop Improvement, ed. R.C. Staples and G.H. Toeniessen, pp. 321-34. New York Wiley. 

The virucidal activity of chemicals is difficult to determine in the laboratory. Tissue culture techniques are the most common methods for growing and estimating viruses however, antimicrobial agents may also adversely affect the tissue culture see also Chapter 11. 

The discovery and exploitation of enzymes in aldoxime-nitrile pathway nitrile hydratase, amidase, nitrilase, aldoxime dehydratase, etc., are shown along with the use of methodologies, such as organic chemistry, microbial screening by enrichment and acclimation culture techniques, enzyme purification, gene cloning, molecular screening by polymerase chain reaction (PCR). 

SCREENING FOR NEW MICROBIAL ENZYMES BY ENRICHMENT AND ACCLIMATION CULTURE TECHNIQUES... 

Gleaves, C. A., etal. (1985). Comparison of standard tube culture and shell vial cell culture techniques for the detection of cytomegalovirus in clinical specimens. J. Clin. Microbiol. 21,217-221. 

Twiss, M., Errecalde, O., Fortin, C., Campbell, P., Jumarie, C., Denizeau, F., Berkelaar, E., Hale, B., and van Rees, K., Coupling the use of computer chemical speciation models and culture techniques in laboratory investigations of trace metal toxicity, Chem Spec Bioavailab, 13 (1), 9-24, 2001. 

Shasby DM, SS Shasby. (1990). Endothelial cells grown on filter membranes. In HM Piper, ed. Cell Culture Techniques in Heart and Vessel Research. Stuttgart Springer-Verlag, pp 212-219. 

An improving in the culturing technique was conceived as feeding the sulfur solely source compound as a rate equal to that of the microorganism intake so as needed for growth [126], This optimization technique is believed to act in two ways, for the proliferation efficiency of the microorganism in the culturing medium and for the desulfurization activity and substrate specificity. 

Continuous culture systems have been widely used to culture microorganisms for industrial and research purposes (Kubitschek 1970 Tempest 1970 Veldkamp 1976 Rhee 1980). In recent years, these culture techniques have found their way into the bioassay methods of ecotoxicology and allelopathy (Rhee 1980). The early development of a continuous culture system can be traced back to the work of Novik and Szilard (1950 a,b) who developed the first chemostat. In a continuous culture system, nutrients are supplied to the cell culture at a constant rate and to maintain a constant volume, an equal volume of cell culture is removed. This allows the cell population to reach a steady state, where the growth rate and the total number of cells/ml of culture remains constant. Two kind of continuous culture systems can be distinguished turbidostat and chemostat. ... 

Microbial Involvement through Enrichment Culturing Techniques...175... 

Microbial Transformation of Organic Chemicals in Natural Environments Fate of Chemicals and Substantiation of Microbial Involvement through Enrichment Culturing Techniques... 

With present anaerobic culturing techniques and the slow growth of these organisms, anaerobes are often not identified until 4 to 7 days after culture, and sensitivity information is difficult to obtain. For this reason, there are usually few data with which to alter the antianaerobic component of the antimicrobial regimen. 

Nutritional and cultural techniques for growing Ochromonas danica in light and darkness have been described (A2, H18). It was grown under constant illumination from five 40-watt warm-white fluorescent lights, ca. 1.0 m from the cultures. Transfers were made weekly in 10 ml of maintenance medium 1ml was used for transfer (Table 6). 

Moreau, J.-F. and Hancock, R. G. V. (1996). Chrono-cultural technique based on the instrumental neutron activation analysis of copper-based artifacts from the contact period of northeastern North America. In Archaeological Chemistry organic, inorganic and biochemical analysis, ed. Orna, M. V., ACS Symposium Series 625, Washington, DC, American Chemical Society, pp. 64-82. 

Chinese hamster ovary cells in which there has been an extensive rearrangement of chromosome material and the chromosome number may not be constant from cell to cell, are frequently used. Polyploidy, endoreduplication and high spontaneous chromosome aberration frequencies can sometimes be found in these established cell lines, but careful cell culture techniques should minimize such effects. Cells should be treated in exponential growth when cells are in all stages of the cell cycle. 

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