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Research conducted on stress and cold shock responses in Escherichia coli to detect and characterize antibacterial compounds is presented. Results include natural source antibiotics identification.

An Escherichia coli strain without the small heat shock proteins IbpA and IbpB was developed. Its growth and viability at high temperatures was compared to those of isogenic cells with null mutations in the clpA, clpB or htpG gene. Findings indicated that the highly conserved E. coli small heat shock proteins are not essential and that their deletion causes only slight changes in growth and viability at high temperatures.

The Escherichia coli cold shock promoter cspA stimulates the production of recombinant proteins at low temperatures. The promoter suppresses protein production at 37 degrees celsius. A reduction in temperature overcomes the repressive effect and there is no need to add chemical inducers. However, the expression of the cspA promoter is suppressed one or two hrs after its transfer to a low temperature medium and the accumulation of proteins decreases.

The ability of beta-lactamase with a deleted leader peptide to interact with cytoplasmic membrane was investigated. Osmotic shock was applied to release this signal peptide-deficient protein from Escherichia coli cells. Fractionation analysis showed that beta-lactamase was able to associate with the cell membrane and was translocated into the periplasmic space even without the leader peptide but with low efficiency. This observation indicated that some mature proteins that are secreted can still interact with the secretory apparatus at a low efficiency even without a leader peptide.

A simple, aqueous route is described for the one-pot synthesis of antibody-derivatized zinc sulfide (ZnS) immuno-quantum dots (QDs). Murine immunoglobin G (IgG) antibodies have displayed high affinity for the protein shell and stable immuno-QDs with hydrodynamic diameter are obtained by mixing biofabricated nanocrystals with human IgG.

A study was conducted to show that Hsp31 plays an important role in the acid resistance of starved Escherichia coli but has little influence on oxidative-stress survival. The findings suggest that Hsp31 did not play any significant role in the management of oxidative damage but helps the cells to handle combination of oxidative and thermal stress.

The nonequilibrium synthesis of Cu2O nanoparticles is accomplished using an engineered derivative of the DNA-binding protein Tral in a room-temperature precursor electrolyte. The results show that a protein with no intrinsic inorganic synthesis activity can be endowed with the ability to control the formation of inorganic nanostructures under thermodynamically unfavorable conditions, reproducing a key feature of biological hard-tissue growth and assembly.