Cultural Methods

These methods are by definition slow, taking from 24 hours to 10-15 days depending on the samples being examined. There is therefore considerable pressure to replace them with faster methods in the modern QC laboratory. They do, however, provide a very powerful amplification of microbial numbers, and are able to detect very low levels of contamination. Therefore these methods are still widely used and indeed are statutory requirements for the analysis of a number of products. 

A number of cultural methods are available for counting. Most of them rely on prior dilution of samples. 

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Sustainable Agriculture. The third factor that will influence the future of pesticide sales is the emphasis on sustainable agriculture systems that rely on more natural pest control methods and reduced pesticide usage. These are integrated systems that requke nutrients and crop protection chemicals from on-farm natural sources and cultural methods. Many current sustainable farms are site-specific systems that may depend on the soils in a... 

In restaurant operations, steriliza tion of dishes is an additional requirement (see STERILIZATION TECHNIQUES). Steriliza tion is deterrnined by the usual swabbing and culturing methods or by employing bacteria tagged with radioactive phosphoms and counting residual radioactivity on the washed dishes (108). 

Briefly stated, the production of chloramphenicol by the surface culture method involves inoculating a shallow layer, usually less than about 2 cm, of a sterile, aqueous nutrient medium with Streptomyces ver)ezuelae and incubating the mixture under aerobic conditions at a temperature between about 20° and 40°C, preferably at room temperature (about 25°C), for a period of about 10 to 15 days. The mycelium is then removed from the liquid and the culture liquid is then treated by methods described for Isolating therefrom tne desired chloramphenicol. 

The process (outlined in Figure 5.7) is more sophisticated in terms of initial plant requirements and is also more difficult and costly to operate. However, the volumes which can be processed exceed by far those used in the surface culture method. In addition, the relative space required is much less per cubic metre of medium. 

The submerged culture process continues to increase in terms of the percentage of dtric acid produced compared to that produced by the surface culture method. Tower bioreactors are preferred over stirred reactors because they cost less, there is less risk of contamination and they are less limited by size. 

Vogelmann H, Bischof A, Pape D, Wagner F (1978) In Alfermann AW, Reinhard E (eds) Production of natural compounds by cell culture methods. GSF, Munich, p 130... 

But once an elective culture method for a particular microbe is available, it may safely be concluded that this organism will also be found in nature under conditions corresponding in detail to those of the culture, and that it will carry out the same transformations. (Van Niel 1955)... 

Hoagland, D. R., Arnon, D. I. "The water-culture method for growing plants without soil," Calif. Agrlc. Exp. Stn. Manual 347, 1950. 

Cultural methods (mostly requiring several days) Morphology... 

Sample preparation, because traditional culture methods require days of resuscitation, selection, and isolation prior to analysis, and so compromise the advantage of MS rapidity. 

Cell Culture Methods Applied to Understanding Carotenoid Recognition and Action... 

Urine specimens usually are examined for the eggs of Schistosoma haemotobium or the trophozoites of Trichomonas vaginalis, although occasionally the larvae of Strongyloides stercoralis may be found in patients with hyperinfection syndrome. Urine is the usual specimen for the diagnosis of Trichomonas infection in males. See below (Vaginal Material) for culture method. Urine is centrifuged, and the sediment is examined microscopically. 

Animal infectivity methods Some viruses do not cause recognizable effects in cell cultures but cause death in the whole animal. In such cases, quantification can only be done by some sort of titration in infected animals. The general procedure is to carry out a serial dilution of the unknown sample, generally at ten-fold dilutions, and samples of each dilution are injected into numbers of sensitive animals. After a suitable incubation period, the fraction of dead and live animals at each dilution is tabulated and an end point dilution is calculated. This is the dilution at which, for example, half of the injected animals die. Although such serial dilution methods are much more cumbersome and much less accurate than cell culture methods, they may be essential for the study of certain types of viruses. 

In Vitro and Tissue Culture Methods for Analysis of Translation Initiation... 

Nichols, H. W. (1973). Growth media - fresh water. In Handbook of Phycological Methods, Culture Methods and Growth Measurement. J. R. Stein (ed), pp 7-24. Cambridge University Press, Cambridge, UK. 

We also conducted experiments to compare our culture method with the standard neurosphere culture. In the standard neurosphere culture, cell number increased approximately nine times over 5 days. Immunostaining showed that the neurosphere cultures contained 54 5.3% nestin+ cells and 41 7.4% nestin+ pIIF cells. This demonstrated that the standard neurosphere culmring method was less efficient than EGF-immobilized substrates for selectively expanding NSCs. Thus, the EGF-immobilized substrates prepared from mixed SAMs with 10% COOH-thiol provided the most efficient method for selective NSC expansion. 

As well as overcoming many of the inherent problems associated with agriculture, plant tissue culture also offers a number of advantages over conventional animal cell culture methods currently being applied to produce biopharmaceutical proteins commercially [8], As plant culture media are relatively simple in composition and do not contain proteins, the cost of the process raw materials is reduced and protein recovery from the medium is easier and cheaper compared with animal cell culture. In addition, as most plant pathogens are unable to infect humans, the risk of pathogenic infections being transferred from the cell culture via the product is also substantially reduced. 

Studies of sequence information from organisms in soil microhabitats and then-gene expression under different management conditions will provide guidelines for designing new and improved culturing methods that resemble their natural niches. 

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