Prediction of Host-Specific Genes by Pan-Genome Analyses of the Korean Ralstonia solanacearum Species Complex

The soil-borne pathogenic Ralstonia solanacearum species complex (RSSC) is a group of plant pathogens that is economically destructive worldwide and has a broad host range, including various solanaceae plants, banana, ginger, sesame, and clove. Previously, Korean RSSC strains isolated from samples of potato bacterial wilt were grouped into four pathotypes based on virulence tests against potato, tomato, eggplant, and pepper. In this study, we sequenced the genomes of 25 Korean RSSC strains selected based on these pathotypes. The newly sequenced genomes were analyzed to determine the phylogenetic relationships between the strains with average nucleotide identity values, and structurally compared via multiple genome alignment using Mauve software. To identify candidate genes responsible for the host specificity of the pathotypes, functional genome comparisons were conducted by analyzing pan-genome orthologous group (POG) and type III secretion system effectors (T3es). POG analyses revealed that a total of 128 genes were shared only in tomato-non-pathogenic strains, 8 genes in tomato-pathogenic strains, 5 genes in eggplant-non-pathogenic strains, 7 genes in eggplant-pathogenic strains, 1 gene in pepper-non-pathogenic strains, and 34 genes in pepper-pathogenic strains. When we analyzed T3es, three host-specific effectors were predicted: RipS3 (SKWP3) and RipH3 (HLK3) were found only in tomato-pathogenic strains, and RipAC (PopC) were found only in eggplant-pathogenic strains. Overall, we identified host-specific genes and effectors that may be responsible for virulence functions in RSSC in silico. The expected characters of those genes suggest that the host range of RSSC is determined by the comprehensive actions of various virulence factors, including effectors, secretion systems, and metabolic enzymes

One-pot sulfa-Michael addition reactions of disulfides using a pyridine-borane complex under blue light irradiation

We report a one-pot sulfa-Michael addition reaction using a disulfide and a pyridine-borane complex under blue light irradiation. This novel synthetic approach has a broad substrate scope and a high functional group tolerance. Mechanistic studies suggest that sequential radical and ionic processes provide a practical solution for constructing carbon-sulfur bonds. © 2022 Korean Chemical Society, Seoul & Wiley-VCH GmbH.FALS

Enantioselective halogenation via asymmetric phase-transfer catalysis

The asymmetric phase-transfer catalysis (PTC) is a flourishing field of contemporary synthetic organic chemistry, and this prominent methodology has been tremendously successful in enantioselective halogenations. Both electrophilic and nucleophilic reaction manifolds were enabled through the exploitation of highly ordered ion pairing and/or hydrogen-bonding interactions around a carefully designed chiral phase-transfer catalyst with an insoluble halogenating reagent as well as a suitable substrate. Fluorination has been the most fruitful, and encouraging results have also been documented with heavier halogens. This review surveys examples of various enantioselective halogenations via the asymmetric PTC from its beginning to prosperity over the past decade. © 2022 Korean Chemical Society, Seoul & Wiley-VCH GmbH.FALS

The Interaction of Human Enteric Pathogens with Plants

There are an increasing number of outbreaks of human pathogens related to fresh produce. Thus, the growth of human pathogens on plants should be explored. Human pathogens can survive under the harsh environments in plants, and can adhere and actively invade plants. Plant-associated microbiota or insects contribute to the survival and transmission of enteric pathogens in plants. Human enteric pathogens also trigger plant innate immunity, but some pathogens–such as Salmonella–can overcome this defense mechanism

Meta-Selective C-H Functionalization of Arylsilanes Using a Silicon Tethered Directing Group

We describe meta-selective C-H functionalization of arylsilanes using a Si-tethered directing group. The current method enables a selective alkenylation of arenes bearing a variety of functional groups, and several electron-deficient olefins are also applicable as coupling partners. Further functional group transformations of the silicon-tethered directing group provide multi substituted arenes efficiently.FALS

Isolation and Genomic Characterization of the T4-Like Bacteriophage PM2 Infecting Pectobacterium carotovorum subsp. carotovorum

In order to control Pectobacterium carotovorum subsp. carotovorum, a novel virulent bacteriophage PM2 was isolated. Bacteriophage PM2 can infect 48% of P. carotovorum subsp. carotovorum and 78% of P. carotovorum subsp. brasilliensis but none of atrosepticum, betavasculorum, odoriferum and wasabiae isolates had been infected with PM2. PM2 phage belongs to the family Myoviridae, and contains a large head and contractile tail. It has a 170,286 base pair genome that encodes 291 open reading frames (ORFs) and 12 tRNAs. Most ORFs in bacteriophage PM2 share a high level of homology with T4-like phages including IME08, RB69, and JS98. Phylogenetic analysis based on the amino acid sequence of terminase large subunits confirmed that PM2 is classified as a T4-like phage. It contains no integrase- or no repressor-coding genes related to the lysogenic cycle, and lifestyle prediction using PHACT software suggested that PM2 is a virulent bacteriophage

Stereochemical modulation of ketyl radical cyclization enabled by pyridine-boryl radicals: catalytic diastereoselective synthesis of trans-2-alkyl-1-indanols

Previously available ketyl radical cyclization conditions suffer from low and uncontrollable diastereoselectivity because of the absence of reagent-substrate interactions. In this report, stereochemical modulation was accomplished by taking advantage of the pyridine-boryl radical, which leaves the synthetically modifiable boronate moiety on the carbonyl oxygen near the reacting center during the stereo-determining cyclization step. In consequence, a catalytic diastereoselective synthesis of trans-2-substituted-1-indanols was achieved in the presence of a sterically congested six-membered diboronic ester and an efficient hydrogen atom donor.FALS

Facile fabrication of ordered Si1-xGex nanostructures via hybrid process of selective epitaxial growth (SEG) and self-assembled nanotemplates

In this study, a facile fabrication method of the ordered Si1-xGex nanodots (NDs) and nanowires (NWs) was successfully developed via hybrid process of selective epitaxial growth (SEG) of Si1-xGex and self-assembled nanotemplates, i.e., anodic aluminum oxide (AAO) and diblock copolymer (DBC) of polystyrene-b-polymethylmethacrylate (PS-b-PMMA). Si1-xGex films were selectively grown on the Si windows against the oxide area at a growth temperature of 550 degrees C by repeating the unit cycle consisting of two consecutive steps; Si1-xGex deposition step using Si2H6 and GeH4 and Cl-2 exposure step for removing the nuclei or deposits formed on the oxide area during the preceding Si1-xGex deposition step. The chemical composition of the Si1-xGex films was readily controlled by adjusting the flow rate of GeH4 from 20 sccm to 45 sccm while that of Si2H6 gas was fixed at 10 sccm, giving rise to the variation of Ge composition in Si1-xGex from 22.2% to 34.0%. In order to fabricate well-ordered Si1-xGex nanostructures, Si windows with hexagonal arrangement were fabricated using AAO and PS-b-PMMA. AAO was prepared through multi-step anodization of the Al films of Al/Si(001) substrate under suitable anodizing conditions. Subsequently, ordered Si windows were fabricated by removing the barrier layer at the bottom of the AAO membrane by reactive ion etching (RIE). In case of PS-b-PMMA, SiO2 templates with ordered Si windows were fabricated through replication of nano-cylindrical pattern of PS-b-PMMA to the 20-nm thick SiO2 layers of SiO2/Si. By utilizing the ordered Si windows obtained from both AAO and PS-b-PMMA, Si1-xGex was selectively grown on Si windows against the oxide area, viz., aluminum oxide in AAO and SiO2 templates. Hexagonally ordered NDs and freestanding NWs were facilely fabricated on the Si substrates after removing the AAO and SiO2 templates. (C) 2012 Elsevier B.V. All rights reserved.X113sciescopu