Microbe strain development

Weed seed longevity is attributed, at least in part, to inhibitors that protect the seed from decay by microbes. One of the reasons weeds pose such a serious problem is because their seeds can persist for decades. This problem might be attacked by either destroying the inhibitors or by developing strains of microbes that can destroy the seeds. 

Some fermentation broths are non-Newtonian due to the presence of microbial mycelia or fermentation products, such as polysaccharides. In some cases, a small amount of water-soluble polymer may be added to the broth to reduce stirrer power requirements, or to protect the microbes against excessive shear forces. These additives may develop non-Newtonian viscosity or even viscoelasticity of the broth, which in turn will affect the aeration characteristics of the fermentor. Viscoelastic liquids exhibit elasticity superimposed on viscosity. The elastic constant, an index of elasticity, is defined as the ratio of stress (Pa) to strain (—), while viscosity is shear stress divided by shear rate (Equation 2.4). The relaxation time (s) is viscosity (Pa s) divided by the elastic constant (Pa). 

The plant-microbe symbiosis may help facilitate the effective use of inoculants. For example, developed (brady)rhizobial strains or root-colonizing pseudomonads may be more effectively introduced into a contaminated soil environment when they are applied in conjunction with theirplant host. Kingsley etal. (1994) showed that inoculation of soil with a 2,4-D-degrader protected germinating seeds from the herbicidal effects of residual pesticide. Thus, plants may be used to help restore treated soils that contain residual but biologically active compounds. 

D Antuono, A.L., Casabuono, A., Couto, A., Ugalde, R.A., Lepek, V.C. Nodule development induced by Mesorhizobium loti mutant strains affected in polysaccharide synthesis. Mol Plant-Microbe Interact 18 (2005) 446-457. 

Unlike mammalian cells, which cannot synthesize all amino acids, SILAC is not well suited to studying the protein/peptide levels of microorganisms, most of which are prototrophic for all amino acids. Application of SILAC in such cases is mostly restricted to auxotrophic strains, which renders the technique ineffective for the proteome analysis of many commercially important microbes. Native SILAC (nSILAC), a recently developed modification of... 

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