Overexpression of a pea DNA helicase 45 in bacteria confers salinity stress tolerance.
ABSTRACT Salinity stress is one of the major factors negatively affecting growth and productivity in living organisms including plants and bacteria resulting in significant losses worldwide. Therefore, it would be fruitful to develop salinity stress tolerant useful species and also to understand the mechanism of stress tolerance. The pea DNA helicase 45 (PDH45) is a DNA and RNA helicase, homologous to eukaryotic translation initiation factor 4A (eIF-4A) and is involved in various processes including protein synthesis, maintaining the basic activities of the cell, upregulation of topoisomerase I activity and salinity stress tolerance in plant, but its role in salinity stress tolerance in bacteria has not heretofore been studied. This study provides an evidence for a novel function of the PDH45 gene in high salinity (NaCl) stress tolerance in bacteria (Eschericia coli, BL21 cells) also. Furthermore, it has been shown that the functionally active PDH45 gene is required to show the stress tolerance in bacteria because the single mutants (E183G or R363Q) and the double mutant (E183G + R363Q) of the gene could not confer the same function. The response was specific to Na+ ions as the bacteria could not grow in presence of LiCl. This study suggests that the cellular response to high salinity stress across prokaryotes and plant kingdom is conserved and also helps in our better understanding of mechanism of stress tolerance in bacteria and plants. It could also be very useful in developing high salinity stress tolerant useful bacteria of agronomic importance. Overall, this study provides an evidence for a novel function of the PDH45 gene in high salinity stress tolerance in bacteria.
Article: Cystadenoma and cystadenocarcinoma with mesenchymal stroma of the liver. Immunohistochemical analysis.[show abstract] [hide abstract]
ABSTRACT: Cystadenoma with mesenchymal stroma is a rare neoplasm of the liver that occurs exclusively in young women and has a potential for malignant transformation. A light microscopic and immunohistochemical study of a case of biliary cystadenoma and another of biliary cystadenocarcinoma revealed a range of differentiation of the lining epithelial cells. The lining cells in the cystadenoma resembled the cells of the normal intrahepatic bile ducts. In contrast, the epithelial lining in the case of cystadenocarcinoma had features of intestinal mucosa, including goblet, Paneth, and endocrine cells similar to those found in other mucinous cystic neoplasms of the foregut area. The compact "ovarianlike" mesenchymal stromal cells had immunohistochemical characteristics of myofibroblasts. These are reactive contractile cells that may proliferate in response to the expanding cysts and female hormones, and they differ immunohistochemically from ovarian stromal cells.Archives of pathology & laboratory medicine 11/1992; 116(10):1047-50. · 2.58 Impact Factor
Article: Two related superfamilies of putative helicases involved in replication, recombination, repair and expression of DNA and RNA genomes.[show abstract] [hide abstract]
ABSTRACT: In the course of systematic analysis of protein sequences containing the purine NTP-binding motif, a new superfamily was delineated which included 25 established or putative helicases of Escherichia coli, yeast, insects, mammals, pox- and herpesviruses, a yeast mitochondrial plasmid and three groups of positive strand RNA viruses. These proteins contained 7 distinct highly conserved segments two of which corresponded to the "A" and "B" sites of the NTP-binding motif. Typical of the new superfamily was an abridged consensus for the "A" site, GxGKS/T, instead of the classical G/AxxxxGKS/T. Secondary structure predictions indicated that each of the conserved segments might constitute a separate structural unit centering at a beta-turn. All previously characterized mutations impairing the function of the yeast helicase RAD3 in DNA repair mapped to one of the conserved segments. A degree of similarity was revealed between the consensus pattern of conserved amino acid residues derived for the new superfamily and that of another recently described protein superfamily including a different set of prokaryotic, eukaryotic and viral (putative) helicases.Nucleic Acids Research 07/1989; 17(12):4713-30. · 8.03 Impact Factor