Secondary metabolite products

The effect of a particular cultivation environment on a system can be evaluated in terms of biomass (fresh/dry weight, cell number), secondary metabolite production [51,75,89,102,103,106,107] or substrate consumption (e.g. carbon source [57] or oxygen [53,108]). Using the Evan s Blue method to identify non-viable cells. Ho et al. [108] used viable cell density measurements to determine variations in specific growth rate attributable to hydrodynamic stress. 

Stizolobium hassjoo 125-ml shake flasks 140-220 rpm (0.4-1.7 m s- ) secondary metabolite production aggregate size [45]... 

In the interdisciplinary field of biophysics and biotechnology, the bioeffects of electric field have received considerable interest for both fundamental studies on these interaction mechanisms and potential application. However, the effects of pulsed electric field (PEF) on secondary metabolism in plant cell cultures and fermentation processes have been unknown. Therefore, it would be very interesting to find out whether PEF could be used as a new tool for stimulating secondary metabolism in plant cell cultures for potential application to the value-added plant-specific secondary metabolite production. Furthermore, if the PEF permeabilization and elicitation are discovered in a cell culture system, the combination of... 

Detection by LDMS and structural elucidation of other secondary metabolite products, generated in the host during the onset of the parasite disease, is discussed. These molecules may serve as additional biomarkers for rapid malaria diagnosis by LDMS. For instance, choline phosphate (CP) is identified as the source of several low-mass ions observed in parasite-infected blood samples in addition to heme biomarker ions. The CP levels track the sample parasitemia levels. This biomarker can provide additional specificity and sensitivity when compared to malaria detection based on heme ion signals alone. Furthermore the observed elevated CP levels are discussed in the context of Plasmodium metabolism during its intra-erythrocytic life cycle. These data can... 

Another field of research is the possibility offered by phytochemicals in protecting plants against diseases and pathogens (fungus, bacteria and nematodes). Numerous studies have suggested that plant-pathogen interactions are partially mediated via plant secondary metabolite production, despite the inconsistency revealed by some works on the ability of particular compounds to provide resistance to a specific pathogen. 

Determining costs of secondary metabolites is inherentiy difficult as a result of the variable responses, multiple physiological roles of the metabolites, as well as the different types of costs involved in the production of secondary metabolites (production, transport, storage, maintenance) (Strauss et al. 2002). Emerging studies are now taking more of these variables into consideration. For example, work with clonal populations of D. pulchra has estimated costs of furanone production in relation to chemical defense and phenotype by investigations of reproductive... 

Figure 3. Relationship between secondary metabolite production, consumption of nitrogen and carbon sources, and growth of the brown-rot fungus Lentinus lepideus (HC-LN medium).

Verpoorte, R. and Memelink, J. 2002. Engineering secondary metabolite production in plants. Current Opinion in Biotechnology, 13 181-187. 

There is also strong evidence indicating that there is an inverse relationship between growth rate and secondary metabolite production (Lindsey and Yeoman, 1983). When growth is intense, the primary processes of the cell are cell division and production of cell mass. In the stationary phase, when growth is minimal, conditions favor the production and accumulation of secondary metabolites. 

Constabel, F., "Principles Underlying the Use of Plant Cell Fermentation for Secondary Metabolite Production," Biochem. Cell. Biol. 66 (1988) 658-664. 

Matlock DB, Ginsburg DW, Paul VJ (1999) Spatial Variability in Secondary Metabolite Production by the Tropical Red Alga Portieria hornemannii. Hydrobiologia 398/399 267... 

Microbial production of secondary metabolites is also an important source of novel therapeutic agents. However, the physiological and biochemical factors that determine the onset of production of a specific secondary metabolite in a particular species are incompletely understood. Generally, a range of analytical techniques, often elaborate, time-consuming and involving extensive sample pre-treatment, have to be developed in order to monitor the details of the metabolic changes and substrate consumption that accompany secondary metabolite production. In order to provide rapid multi-parametric information about the microbial fermentation process, H HPLC-NMR has been applied to characterise microbial metabolites directly in the broth supernatants from a... 

DI Thomas, JH Cove, S Baumberg, CA Jones, BAM Rudd. Plasmid effects on secondary metabolite production by a streptomycete synthesizing an anthelmintic mac-rolide. J Gen Microbiol 137 2331-2337, 1991. 

Plants are known as a potential source of a large number of important biochemical constituents (1-3). In recent years, transformed hairy roots have been studied as a potential large-scale source for production of plant-derived useful compounds such as pharmaceuticals. They have several advantages compared to plant cell suspension culture, such as high growth rate, high and stable secondary metabolite productivity, autotrophy of... 

---