Inhibition of Pinus radiata Primary Needle Epicuticular Wax Biosynthesis by Trichloroacetate

High concentrations (1000 parts 10^–6) of trichloroacetate(TCA) inhibit germination of Pinus radiata seed. Seedlings growingin the presence of lower concentrations (100 parts 10^–6)take up TCA where it becomes concentrated in cotyledons anddeveloping primary needles. TCA inhibits biosynthesis of nonacosan-10-oland long chain diol constituents of the primary needle epicuticularwax concomitant with a reduction in appearance of tubular waxexcept around stomatal pores. Epicuticular wax from TCA-treatedplants consists mainly of alkyl esters, and is amorphous. Itis suggested that P. radiata stomatal subsidiary cells possesstubular epicuticular wax chemically distinct from that of epidermalcells.     

ParA encoded on chromosome II of Deinococcus radiodurans binds to nucleoid and inhibits cell division in Escherichia coli

Bacterial genome segregation and cell division has been studied mostly in bacteria harbouring single circular chromosome and low-copy plasmids. Deinococcus radiodurans, a radiation-resistant bacterium, harbours multipartite genome system. Chromosome I encodes majority of the functions required for normal growth while other replicons encode mostly the proteins involved in secondary functions. Here, we report the characterization of putative P-loop ATPase (ParA2) encoded on chromosome II of D. radiodurans. Recombinant ParA2 was found to be a DNA-binding ATPase. E. coli cells expressing ParA2 showed cell division inhibition and mislocalization of FtsZ-YFP and those expressing ParA2-CFP showed multiple CFP foci formation on the nucleoid. Although, in trans expression of ParA2 failed to complement SlmA loss per se, it could induce unequal cell division in slmAminCDE double mutant. These results suggested that ParA2 is a nucleoid-binding protein, which could inhibits cell division in E. coli by affecting the correct localization of FtsZ and thereby cytokinesis. Helping slmAminCDE mutant to produce minicells, a phenotype associated with mutations in the ‘Min’ proteins, further indicated the possibility of ParA2 regulating cell division by bringing nucleoid compaction at the vicinity of septum growth.