Statistical methods have been implemented to justify and determine realistic values of the elemental (pseudo-molecular) composition of living cells. Several species and genera have been studied, ranging from microorganisms (prokaryotes, fungi) to mammalian cells. About microorganisms, this paper analyzes many different situations (growth rates, metabolic regimes, culture media, etc.). We also considered different human tissues. By temporarily excluding higher plants, we concluded that the elemental composition of C, H, O, and N, exceeding 95% of the dry cell weight, is almost universally the same for all cells, regardless of cell types and the operating regime (respiratory or fermentative, for example). We obtain the following "universal" value: CH1.74O0.49 N0.18 .

 

Heat stress is a major abiotic stress limiting plant growth and productivity in many areas of the world. Heat stress induces the production of a group of proteins called heat-shock proteins (Hsps) or stress-induced proteins. (Hsps)/chaperones are responsible for protein folding, assembly, translocation and degradation in many normal cellular processes, stabilize proteins and membranes and can assist in protein refolding under stress conditions. They can also play a crucial role in protecting plants against stress by reestablishing normal protein conformation. In the present study we have identified Hsps/chaperones from ESTs in safflower (Carthamus tincotius L.) drought responsive ESTs. The putative function data was manually screened for the identification of putative heat shock proteins/chaperons from safflower ESTs. The identified Hsps/chaperones were found to be localized in cytoplasm, mitochondrion, chloroplast, thylakoid membrane and chloroplast. Out of fifty motifs identified in safflower ESTs, AAG is repeated for 18 times, followed by (CGT, GTG) 15 times, (AGA, AGC, ATT, TTC, CAC, GTT, TGT) 12 times. In silico studies revealed the abundance of amino acid serine followed by argnine and valine in Hsps.In this study, Hsps putative sequence (Acc. # GW584254) showed, 68% homology with soybean, heat shock protein, Gmhsp17.5-E gene with complete CDs and this heat shock protein gene has been isolated for in silico cloning. The gene is of 1678bp with an open reading frame (ORF) of 465bp, with predicted to encode a protein of 154 amino acid residues with the theoretical pI of 5.25 and calculated molecular weight of 37.4 kDa. It is concluded that SFHSP might be a stress-related gene in safflower under abiotic stress conditions. Further investigation is needed to gain more information about the function and regulatory mechanism of SFHSP in plant-stress responses particularly in safflower.