Allele mining for a drought responsive gene DRO1 determining root growth angle in donors of drought tolerance in rice (Oryza sativa L.)

Deeper Rooting 1 (DRO1) gene identified from a major QTL on chromosome 9 increases the root growth angle (RGA) and thus facilitates survival under drought and hence is an excellent candidate for rice improvement. Twenty-four major Indian upland and lowland genotypes including the ‘yield under drought’ (DTY) QTL donors were subjected to allele mining of DRO1 (3058 bp) using four pairs of overlapping primers. A total of 216 and 52 SNPs were identified across all genotypes in the gene and coding region (756 bp) respectively with transversions 3.6 fold more common than transitions in the gene and 2.5 times in the CDS. In 251 amino acid long protein, substitutions were found in 19 positions, wherein change in position 92 was the most frequent. Based on allele mining, the 24 genotypes can be classified into 16 primary structure variants ranging from complete functional allele (Satti, IR36 and DTY 3.1 donor, IR81896-B-B-195) to truncated non-functional alleles in PMK2, IR64, IR20 and Swarna. All the DTY donors, other than IR81896-B-B-195, and most of the upland drought tolerant cultivars (Nagina 22, Vandana and Dhagaddeshi) had accumulated 6–19 SNPs and 4–8 amino acid substitutions resulting in substantial differences in their protein structure. The expression analysis revealed that all the genotypes showed upregulation under drought stress though the degree of upregulation varied among genotypes. The information on structural variations in DRO1 gene will be very useful for the breeders, especially in the light of recent breeding programmes on improving drought tolerance using several DTY donors and upland accessions.Supplementary InformationThe online version of this article (10.1007/s12298-021-00950-2).     

Lipid and membrane fluidity abnormalities in platelets and megakaryocytes of the hereditary macrothrombocytopenic Wistar Furth rat.

Biochemical and functional abnormalities of megakaryocytes and platelets were studied in Wistar Furth (WF) rats which have genetically determined macrothrombocytopenia and megakaryocytopenia, and were compared with their counterparts in Sprague-Dawley (SD) rats. Both megakaryocytes and platelets synthesized phospholipids from [14C]acetate. WF and SD megakaryocytes incorporated 0.27 and 0.29 nmol acetate per 10(6) cells, respectively. Phosphatidylcholine (PC) accounted for 64% and 58% of the PL radioactive label in megakaryocytes of SD and WF rats, respectively, (P less than 0.05), while 69% of labeled activity was associated with PC of SD platelets compared to 60% found in PC of WF platelets (P less than 0.01). In WF platelets a significant increase in the levels of lysophosphatidylcholine (6.1% vs. 3.0%) was observed. WF platelets had substantially higher levels of esterified cholesterol, triglycerides, ceramides and a 3-fold increase in the total protein per platelet compared to SD platelets. The fatty acid composition of WF platelet PC showed quantitative abnormalities. Plasma lecithin-cholesterol acyl transferase activity and platelet function monitored by the uptake and release of [14C] serotonin showed nonsignificant variations between SD and WF rats. Compared with the control, platelet membrane fluidity, measured by fluorescence polarization using platelets labeled with 1,6-diphenyl-1,3,5-hexatriene, was significantly decreased in the WF rats.     

Inhibition of α-, β- and γ-carbonic anhydrases from the pathogenic bacterium Vibrio cholerae with aromatic sulphonamides and clinically licenced drugs – a joint docking/molecular dynamics study

The binding mode of aromatic sulphonamides and clinically licenced drugs to the three carbonic anhydrase (CA, EC 4.2.1.1) isoforms from the human pathogen V. cholerae was here thouroghly characterised by a joint docking and molecular dynamics in silico protocol. In fact, VchCA, VchCAβ, and VchCAγ are crucial in the pathogen life cycle and growth and represent innovative targets to fight V. cholerae proliferation overcoming the spreading chemoresistance to the available drugs. A set of 40 sulphonamides/sulfamates VchCAs inhibitors was studied using the proteins homology built 3 D models unveiling the key and stable interactions responsible for a potent CA inhibition. This study has the aim to offer insights and guidelines for the future rational design of potent and selective inhibitors targeting CA isoforms from V. cholerae or other human pathogens.     

One-electron reduction of carcinogen chromate by microsomes, mitochondria, and Escherichia coli: identification of Cr(V) and .OH radical.

Earlier studies have shown that a long-lived Cr(V) species is produced during the reduction of chromate (Cr(VI] by microsomes/NADPH, mitochondria, and other cellular constituents and that this Cr(V) species plays a significant role in the mechanism of Cr(VI) toxicity. The present work indicates that this species is a Cr(V) complex involving the diol moieties of NADPH as the ligand. Additionally, ESR spin trapping investigations show that the hydroxyl (.OH) radical is also generated in the reduction process. Hydrogen peroxide (H2O2) enhances the .OH generation but suppresses the Cr(V)-NADPH complex formation. Catalase decreases the .OH radical generation and enhances the Cr(V)-NADPH formation. Measurements under anaerobic atmosphere show decreased .OH radical generation, indicating that during the cellular Cr(VI) reduction process molecular oxygen is reduced to H2O2, which reacts with the Cr(V)-NADPH complex to generate the .OH radical via a Fenton-like mechanism.     

Gremlin in the pathogenesis of hepatocellular carcinoma complicating chronic hepatitis C: an immunohistochemical and PCR study of human liver biopsies

ABSTRACT: BACKGROUND: The possible role of secretory products of fibrous tissue in the development of hepatocellular carcinoma (HCC) complicating chronic hepatitis C was investigated. Our hypothesis was that gremlin, secreted by fibroblasts, inhibited bone morphogenic protein (BMP), which mediates stem cell maturation into adult functioning hepatocytes, and thus, arrest stem cell maturation and promoted their proliferation in an immature state possibly culminating into development of HCCs. RESULTS: Protein expression of cytokeratin 19 (CK19) and fibroblast growth factor 2 (FGF-2), and mRNA expression of gremlin and BMP-7 were studied in 35 cases of chronic hepatitis, cirrhosis and HCC complicating chronic hepatitis C. CK19 expression was higher in cases of cirrhosis (0.004), which correlated with the grade (r=0.64, p=0.009) and stage (r=0.71, p=0.001). All HCCs were negative for CK19. Stem cell niche activation (as indicated as a ductular reaction) was highest in cases of cirrhosis (p=0.001) and correlated with CK19 expression (r=0.42, p=0.012), the grade(r=0.56, p=0.024) and stage (0.66, p=0.006). FGF-2 expression was highest in HCCs and correlated with the grade (r=0.6, p=0.013), stage (0.72, p=0.002), CK19 expression (r=0.71, p=002) and ductular reaction (0.68, p=0.004) in hepatitis cases. Higher numbers of cirrhosis cases and HCCs (p=0.009) showed gremlin expression, which correlated with the stage (r=0.7, p=0.002). Gremlin expression correlated with that of CK19 (r=0.699, p=0.003) and FGF2 (r=0.75, p=0.001) in hepatitis cases. CONCLUSIONS: Fibrosis promotes carcinogenesis by fibroblast-secreted gremlin that blocks BMP function and promotes stem cell activation and proliferation as well as possibly HCC development.