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Uranium contamination is a widespread problem caused by natural and anthropogenic activities. Although microorganisms thrive in uranium-contaminated environments, little is known about the actual molecular mechanisms mediating uranium resistance. Here, we investigated the resistance mechanisms driving the adaptation of Cupriavidus metallidurans NA4 to toxic uranium concentrations. We selected a spontaneous mutant able to grow in the presence of 1 mM uranyl nitrate compared to 250 µM for the parental strain. The increased uranium resistance was acquired via the formation of periplasmic uranium-phosphate precipitates facilitated by the increased expression of a genus-specific small periplasmic protein, PrsQ2, regulated as non-cognate target of the CzcS2-CzcR2 two-component system. This study shows that bacteria can adapt to toxic uranium concentrations and explicates the complete genetic circuit behind the adaptation.

Uranium contamination is a widespread problem caused by natural and anthropogenic activities. Although microorganisms thrive in uranium-contaminated environments, little is known about the actual molecular mechanisms mediating uranium resistance. Here, we investigated the resistance mechanisms driving the adaptation of Cupriavidus metallidurans NA4 to toxic uranium concentrations. We selected a spontaneous mutant able to grow in the presence of 1 mM uranyl nitrate compared to 250 µM for the parental strain. The increased uranium resistance was acquired via the formation of periplasmic uranium-phosphate precipitates facilitated by the increased expression of a genus-specific small periplasmic protein, PrsQ

The hallmark of human evolution encompasses the dramatic increase in brain size and complexity. The intricate interplays of micro-RNAs (miRNAs) and their target genes are indispensable in brain development. Sequence divergence in distinct structural regions of Brain-specific precursor miRNAs (pre-miRNAs) and its consequence in the production of corresponding mature miRNAs in human are unknown. To address these questions, first we classified miRNAs into three categories based on tissue expression: Brain-specific (expressed exclusively in brain), Non-brain (expressed in Non-brain tissues) and Common (expressed in all tissues) and compared the sequence divergence of different structural regions (basal segment, lower and upper stem, internal and terminal loop) of categorized pre-miRNAs across human, non-human primates and rodents. Our analysis revealed that unpaired regions of Brain-specific pre-miRNAs in human bear traces of relatively high rate of evolutionary divergence compared to those in other species. Cross-tissue expression analysis unveiled the higher expression of the Brain-specific miRNAs in human compared to other species. Intriguingly, in human brain, expression levels of these miRNAs superseded the levels of the ubiquitously expressed “Common-miRNAs”. Further analysis revealed that presence of certain motif and nucleotide preference in the Brain-specific pre-miRNAs may favor DROSHA and DICER to ameliorate miRNA processing. The higher processing efficiency of human Brain-specific miRNAs was reflected as an elevated production of corresponding mature miRNAs in the human brain. Finally, re-construction of gene-regulatory network uncovers different pathways driven by Brain-specific miRNAs that may contribute to the development of brain in human.

Haridhan rice was discovered by a farmer in his field which was planted with the widely cultivated mega-rice BR11. He noticed Haridhan’s variant characters compared to BR11, saved the seeds, planted it in 4–5 successive generations and noted the increase in yield with low input in fertilizer. Due to the overall similarity between BR11 and Haridhan, breeders were unwilling to call the latter a different genotype. This study was therefore performed to investigate the genetic similarity between BR11 and Haridhan. Polymorphism between Haridhan and BR11 using 115 SSR markers was 25 %, close to the reported 11 % for essentially derived (EDV) maize inbred lines. Similarly, 40 RAPD and 1,536 SNP markers showed polymorphism to be 16 % and 5 %, respectively. SSR polymorphic loci between the two were absent in chr 4, 6 and 9 but present in variable numbers in the rest. Some of the embedded and highly polymorphic SSRs were found in the 5′UTR of regulatory genes like Ser–Thr protein kinase and evolutionarily conserved C-terminal protein and revealed a common motif for binding TRA2-BETA1, a Serine–Arginine-rich protein involved in regulating and selecting splice sites. Genetic distance based on the Dice coefficient between Haridhan and BR11 as well as the cultivars, Lal Swarna and Guti Swarna planted in neighboring fields is 0.24, 0.26 and 0.20, respectively, compared to an average of 0.03 for EDV’s like maize inbred lines. Therefore, Haridhan could possibly have been derived from a cross of BR11 with another BR11 having outcrossed genes from the rice cultivars Lal Swarna and Guti Swarna.