Novel N-Black In2O3-x/InVO4 heterojunction for efficient photocatalytic fixation: Synergistic effect of exposed (321) facet and oxygen vacancy

Utilizing semiconductors to catalyze N2 into NH3 has brought great promise in alleviating the issue of energy shortage. However, the wide band gap and high recombination rate of photogenerated (e-/h+)...

Large genetic diversity and strong positive selection in F-box and GPCR genes among the wild isolates of Caenorhabditis elegans

The F-box and chemosensory GPCR (csGPCR) gene families are greatly expanded in nematodes, including the model organism Caenorhabditis elegans, compared to insects and vertebrates. However, the intraspecific evolution of these two gene families in nematodes remain unexamined. In this study, we analyzed the genomic sequences of 330 recently sequenced wild isolates of C. elegans using a range of population genetics approaches. We found that F-box and csGPCR genes, especially the Srw family csGPCRs, showed much more diversity than other gene families. Population structure analysis and phylogenetic analysis divided the wild strains into eight non-Hawaiian and three Hawaiian subpopulations. Some Hawaiian strains appeared to be more ancestral than all other strains. F-box and csGPCR genes maintained a great amount of the ancestral variants in the Hawaiian subpopulation and their divergence among the non-Hawaiian subpopulations contributed significantly to population structure. These genes are mostly located at the chromosomal arms and high recombination rate correlates with their large polymorphism. Gene flow might also contribute to their diversity. Moreover, we identified signatures of strong positive selection in the F-box and csGPCR genes in the non-Hawaiian population using both neutrality tests and Extended Haplotype Homozygosity analysis. Accumulation of high frequency derived alleles in these genes were found in non-Hawaiian population, leading to divergence from the ancestral genotype found in Hawaiian strains. In summary, we found that F-box and csGPCR genes harbour a large pool of natural variants, which may be subjected to positive selection during the recent selective sweep in non-Hawaiian population. These variants are mostly mapped to the substrate-recognition domains of F-box proteins and the extracellular regions of csGPCRs, possibly resulting in advantages during adaptation by affecting protein degradation and the sensing of environmental cues, respectively.Significance statementThe small nematode Caenorhabditis elegans has emerged as an important organism in studying the genetic mechanisms of evolution. F-box and chemosensory GPCR are two of the largest gene families in C. elegans, but their intraspecific evolution within C. elegans was not studied before. In this work, using the nonsynonymous SNV data of 330 C. elegans wild isolates, we found that F-box and chemosensory GPCR genes showed larger polymorphisms and stronger positive selection than other genes. The large diversity is likely the result of rapid gene family expansion, high recombination rate, and gene flow. Analysis of subpopulation suggests that positive selection of these genes occurred most strongly in the non-Hawaiian population, which underwent a selective sweep possibly linked to human activities.

Photostable 3D heterojunction photoanode made of ZnO nanosheets coated onto TiO2 nanowire arrays for photoelectrochemical solar hydrogen generation

Applications of single-phase TiO2 and ZnO in the field of photoelectrochemical (PEC) solar hydrogen generation are limited by their high recombination rate of photogenerated charge carriers.

Novel Staphylococcal Cassette Chromosome composite island (SCC-CI) with a new subtype ofSCCmecVI cassette found in ST5 MRSA in France

ABSTRACTAn emergent kanamycin-susceptible ST5-MRSA lineage has been identified in France. Whole genome sequencing revealed a 40 kb SCC composite island with a mosaic structure including 3 SCC elements: a ΨSCCcop/ars, a SCCLim88Awith accrC recombinase, and a novel subtype of SCCmectype VI (VIb). This mosaic structure suggests a high recombination rate of SCC elements from distinct staphylococci species.

Wafer Level Recombination Carrier Lifetime Measurements of 4H-SiC PiN Epitaxial Wafers

Effective recombination lifetimes of 4H-SiC PiN epitaxy wafers are measured by -PCD (microwave photoconductive decay) system at wafer level. Lifetimes measured in presence and absence of the p+ layer show lower lifetime values with p+ layer present. This is attributed to high recombination rate at p+/n- interface. Lifetimes at various buffer thicknesses show lower values at the buffer layer of about 50 m due to high interface recombination rate resulting from rougher surface of the buffer layer. Lifetimes of PiN wafers from interrupted and continuous p+/n- growth are very comparable.

Evidence for Retroviral Intramolecular Recombinations

ABSTRACT As a consequence of being diploid, retroviruses have a high recombination rate. Naturally occurring retroviruses contain two repeat sequences (R regions) flanking either end of their RNA genomes, and recombination between these two R regions occurs at a high rate. We deduced that recombination may occur between two sequences within the same RNA molecule (intramolecular) as well as between sequences present within two separate RNA molecules (intermolecular). Intramolecular recombination would usually result in a deletion within the progeny provirus. In this report, we demonstrate that intramolecular recombination between two identical sequences occurred within a chimeric RNA vector. In addition, high rates of recombination between two identical sequences within the same RNA molecule resulted mostly from intramolecular recombination.