Culture Work

At present, cell culture work is done mostly by hand by horticulturists in large greenhouses (Plate 3). Chemical engineers could greatly increase the usefulness of this method of plant propagation by developing efficient automated processes for producing plants from cloned cells. 

Effective management of microbiology collections requires that the cultures meet current and future international standard requirements of biotechnology industries. The knowledge and competence of the scientists performing cell culture work obviously impact the quality of the cultures. 

A significant contribution to the formulation of a defined growth medium was made by Murashige and Skoog (1962). The medium that they formulated (known as the MS medium) has since proved to be one of the most widely used in plant cell culture work. The recipe for MS medium is given in Table 5.7. 

We would like to thank Dr. Prabir Bhattacharya, Dr. Kathleen A. Presper, Dr. Joseph R. Moskal, Mr. Alex Vuckovic, and Mr. William G. Shanabruch for help in the lectin binding studies and cell culture work. 

Based partly on anecdotal evidence from culture work, observations in waste water treatment systems with very high particulate loads, the tendency of nitrifiers to grow in aggregates in bioreactor biofilms, and the prevalence of small particles in natural waters, it has been suggested that nitrification occurs mainly on particles and is mediated by particle-attached bacteria (Hagopian and Riley, 1998). Nitrifier sequences were found both associated with particles and in the bulk seawater phase in the northwestern Mediterranean Sea. In the clone library of 16S rRNA sequences, Nitrosomonas-like sequences were preferentially associated with particles and Nitrosospira-]ike sequences dominated in clones from the planktonic phase (PhiUips et al, 1999). This may indicate niche preference by the different groups on the basis of attachment to particles, substrate concentration or other physical/... 

Before we begin, we provide a brief comment on units. In general, we recommend that concentrations ofN compounds be presented as pmol N (i.e., pM, or some similar metric equivalent) and rates to be presented as pmol N time h Historically the pg-at N unit has been used in the presentation of N uptake rates, particularly in culture work 1 pmol of a compound is equal to 1 pg-at N for a... 

In addition to the possibhity of P limitation, Fe control of N2 fixation has become increasingly apparent. Most studies on Fe limitation and N2 fixation have examined the cyanobacterium Trichodesmium spp., since they are known as major contributors of new N to ohgotrophic marine ecosystems. Rueter, (1988) and Paerl et al. (1994) suggested that natural populations could be Fe-hmited and hence Fe would affect the input of new fixed N to the ocean. Later, laboratory culture work also demonstrated that the addition of Fe stimulates N2 fixation (Berman-Frank et al., 2001 Fu and Bell, 2003a Kustka et al., 2003). Berman-Frank and her colleagues, (2001) used seasonal maps of aeohan iron fluxes and model-derived maps of surface water total dissolved Fe to suggest that in 75% of the ohgotrophic ocean, Fe availability limits N2 fixation by Trichodesmium. 

Another specific application is the use of 0.1 pm syringe filters for the removal of mycoplasma in tissue culture work. They are capable of removing 99.99% of three common human mycoplasma species (M. hominis, M. salivarium and M. fermentans) and two common contaminants of fetal calf serum (M. arginini and Acholeplasma Laidlawii) [Hoffman, 1989]. 

Singer, R. (1958). Mycological investigation on teonanacatl, the Mexican hallucinogenic mushroom. 1 The history of teonanacatl, field work and culture work. Mycologia, 50, 239-261. 

Wirsen, 1981 Juniper Tebo, 1995). To date, however, little phylogenetic or culture work has been done specifically on plume microbes. 

Pure culture work" is being carried on in connection with the development of the activated sludge process. Organisms which ars found to be especially rapid nitrifiers are chosen and added in large amounts to the activated sludge tanks. 

Singer, R. Mycotogical Investigations on Teonan catl, The Mexican Hallucinogenic Mushroom. Part 1. The History of Teonanacatl, Field Work and Culture Work Mycologia (1953) 50 239-261... 

The contribution of Dr. Shobha Mareddy in the processing of the cell culture work is gratefully acknowledged. 

There are five primary sources of contamination in mushroom culture work ... 

Mushrooms—and all living organisms—are in constant competition for available nutrients. In creating a sterile environment, the cultivator seeks to give advantage to the mushroom over the myriad legions of other competitors. Before culture work can begin, the first step is the construction of an inoculation chamber or sterile laboratory. 

There has been an interest in looking at not only the effect of low and Hmit-ing nutrient concentrations, but also nutrient ratios. Since N and P are the major nutrients which may potentially limit phytoplankton primary production, the N/P ratio has been changed in culture work. One should also remember that this ratio really varies in many coastal- and near- shore waters. Myklestad and Haug [36] cultured the marine diatom C. affinis in media with different N/P ratios. Figure 3 shows the effect on the production of extracellular polysaccharide in 12-day cultures. Since a clear indication of higher production was seen in... 

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