Bacterial abundance production

Luminous bacteria are bioluminescent microorganisms whose luciferase genes (lux), proteins and intact cells are widely used in applied research and commercial products. Acknowledging the commercial value of luminescent cells also in entertainment and education, we have conducted research on luminous bacteria from marine samples and have isolated Photobacterium phosphoreum (strain RL-1) from coastal marine sediment. In order to maximize the luminescence activity of RL-1, we examined a series of extracts prepared from dried marine foodstuff. Because chitinous compounds and some amino acids are known to be abundant in dried squid and shrimp, we also tested the effects of those compounds on the luminescence activity. Among the supplemental compounds tested, chitosan, cysteine, and aspartic acid were found to enhance the luminescence activity of RL-1. The present results indicate that some amino acids and chitinous compounds are effective supplements for further enhancing bacterial light production in an enriched medium (SWC ). 

With the present lack of synoptic tools for surveying bacterial abundance, data on the abundance and production of heterotrophic bacteria in the Eastern Mediterranean are more sporadic than for phytoplankton chlorophyll and depend on discrete depth sampling and analysis. The data available are for the Cyprus Eddy in summer (Zohary Robarts, 1992) and in winter (Zohary etal., 1998), and in the Cretan Sea in March and September (van Wambeke etal., 2000), and a general survey of the Levantine Basin in fall (Robarts etal., 1996). Some additional data exists for the Western Mediterranean which will not be reviewed here. 

As has been noted above, the Eastern Mediterranean is characterised by many eddies and jets (POEM, 1992). Indeed there are almost no areas of the basin which are not part of some mesoscale feature or other (Fig. 4.3). Yet the nutrient distribution (Kress Herat, 2001) and many of the plankton features such as bacterial abundance and activity and chlorophyll content (Yacobi etal., 1995) seem to be nearly constant across large parts of the basin except for those locations where they intersect major and persistent mesoscale features (Fig. 4.5). Under those circumstances major changes in nutrient distribution and productivity can be seen. The Rhodes Gyre and the Cyprus Eddy (aka Shikmona Gyre) are permanent features which always have an effect on the local biogeochemistry and have been studied in some detail. 

Robarts, R. D., Zohary, T., Waiser, M.J. and Yacobi, Y.Z. (1996) Bacterial abundance, biomass, and production in relation to phytoplankton biomass in the Levantine Basin of the southeastern Mediterranean Sea. Marine Ecology Progress Series, 137, 273-281. 

There have been several studies of bacterial abundance and productivity in the Arabian Sea (Ducklow, 1993 Ramaiah etal., 1996 Wiehinga etal., 1997 Campbell etal., 1998 Garrison etal., 2000 Pomroy Joint, 1999 Ducklow etal., 2001). These have revealed that the heterotrophic bacteria, expectedly most abundant in the surface layer, numerically dominate microbial population also, their abundance in the region (>5 x 108 cells l-1) is generally higher throughout the year as compared to other tropical regions. 

Ramaiah, N., Raghukumar, S. and Gauns, M. (1996) Bacterial abundance and production in the central and eastern Arabian Sea. Current Science (Bangalore), 71, 878—882. 

The study of biochemical natural products has also been aided through the application of two-dimensional GC. In many studies, it has been observed that volatile organic compounds from plants (for example, in fruits) show species-specific distributions in chiral abundances. Observations have shown that related species produce similar compounds, but at differing ratios, and the study of such distributions yields information on speciation and plant genetics. In particular, the determination of hydroxyl fatty acid adducts produced from bacterial processes has been a successful application. In the reported applications, enantiomeric determination of polyhydroxyl alkanoic acids extracted from intracellular regions has been enabled (45). 

As noted above, whole-cell MALDI-TOF MS was intended for rapid taxonomic identification of bacteria. Neither the analysis of specific targeted bacterial proteins, nor the discovery of new proteins, was envisioned as a routine application for which whole cells would be used. An unknown or target protein might not have the abundance or proton affinity to facilitate its detection from such a complex mixture containing literally thousands of other proteins. Thus, for many applications, the analysis of proteins from chromatographically separated fractions remains a more productive approach. From a historical perspective, whole-cell MALDI is a logical extension of MALDI analysis of isolated cellular proteins. After all, purified proteins can be obtained from bacteria after different levels of purification. Differences in method often reflect how much purification is done prior to analysis. With whole-cell MALDI the answer is literally none. Some methods attempt to combine the benefits of the rapid whole cell approach with a minimal level of sample preparation, often based on the analysis of crude fractions rather... 

Viruses are also present in the sea and are so abundant that they are probably the major life form in the ocean. They infect all kinds of microbes and are responsible for a significant amount (10 to 40%) of bacterial mortality primarily through cell lysis. This process has two important effects (1) it releases the bacteria s cytoplasmic DOM (dissolved organic matter) into seawater, where it is consumed by other bacteria, thereby boosting microbial productivity, and (2) viruses acquire genetic material from their host and transmit it into the next host cell that they infect. This leads to a transmission of genetic material whose consequence is as yet unknown. 

Cellulose, the most abundant of all biopolymers, is extremely stable but is attacked by a host of bacterial and fungal (3-glycanases.96 Animals do not ordinarily produce cellulases but some termites do.97 Cellulase structures are varied, being represented by 10 of 57 different glycosylhydrolase families.98 Most, like lysozyme, retain the P configuration in their products but some invert.98 100... 

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