Chiral Catalyst-Directed Dynamic Kinetic Diastereoselective Acylation of Lactols for <i>De Novo</i> Synthesis of Carbohydrate

The control of the stereochemistry at the anomeric position is still one of the major challenges of synthetic carbohydrate chemistry. We have developed a new strategy consisting of a chiral catalyst-directed acylation followed by a palladium-catalyzed glycosidation to achieve high α- and β-stereoselectivity on the anomeric position. The former process involves a dynamic kinetic diastereoselective acylation of lactols derived from Achmatowicz rearrangement, while the latter is a stereospecific palladium-catalyzed allylic alkylation

Additional file 1: Table S1. of NGS in argininosuccinic aciduria detects a mutation (D145G) which drives alternative splicing of ASL: a case report study

10 Variants identified in 8 urea cycle related genes by targeted array NGS. (XLSX 10 kb

Characterization of a novel HIV-1 unique recombinant form between CRF07_BC and CRF55_01B in men who have sex with men in Guangzhou, China

<div><p>Here, we report the genetic diversity of HIV-1 and emergence of novel HIV-1 unique recombinant forms (URF) in both HIV-infected intravenous drug users (IDU) and men who have sex with men (MSM) in Guangzhou, China. We further characterized a novel URF strain isolated from an HIV-infected MSM, GD698. Near full-length genome (NFLG) phylogenic analysis showed that this novel URF was composed of CRF07_BC and CRF55_01B, with two recombinant breakpoints (nt 6,003 and 8,251 relative to the HXB2 genome) in the <i>vpu/env</i> and <i>env</i> genes, respectively. Twenty six percent of the genome is classified as CRF55_01B, spanning part of <i>vpu</i> and most of the <i>env</i> gene. The remaining 74% of the genome is classified as CRF07_BC. Both the backbone CRF07_BC sequence and CRF55_01B fragment were clustered with the HIV-1 isolates found in MSM. The emergence of the novel HIV-1 recombinant indicates the ongoing recombinants derived from the CRF07_BC and CRF55_01B isolates, and provides critical insights into our understanding of the dynamics and complexity of the HIV-1 epidemic in China.</p></div

Additional file 1 of Associations between type 1 diabetes and pulmonary tuberculosis: a bidirectional mendelian randomization study

Supplementary Material

Demonstration of the Presence of the “Deleted” <i>MIR122</i> Gene in HepG2 Cells

<div><p>MicroRNA 122 (miR-122) is highly expressed in the liver where it influences diverse biological processes and pathways, including hepatitis C virus replication and metabolism of iron and cholesterol. It is processed from a long non-coding primary transcript (~7.5 kb) and the gene has two evolutionarily-conserved regions containing the pri-mir-122 promoter and pre-mir-122 hairpin region. Several groups reported that the widely-used hepatocytic cell line HepG2 had deficient expression of miR-122, previously ascribed to deletion of the pre-mir-122 stem-loop region. We aimed to characterise this deletion by direct sequencing of 6078 bp containing the pri-mir-122 promoter and pre-mir-122 stem-loop region in HepG2 and Huh-7, a control hepatocytic cell line reported to express miR-122, supported by sequence analysis of cloned genomic DNA. In contrast to previous findings, the entire sequence was present in both cell lines. Ten SNPs were heterozygous in HepG2 indicating that DNA was present in two copies. Three validation isolates of HepG2 were sequenced, showing identical genotype to the original in two, whereas the third was different. Investigation of promoter chromatin status by FAIRE showed that Huh-7 cells had 6.2 ± 0.19- and 2.7 ± 0.01- fold more accessible chromatin at the proximal (HNF4α-binding) and distal DR1 transcription factor sites, compared to HepG2 cells (p=0.03 and 0.001, respectively). This was substantiated by ENCODE genome annotations, which showed a DNAse I hypersensitive site in the pri-mir-122 promoter in Huh-7 that was absent in HepG2 cells. While the origin of the reported deletion is unclear, cell lines should be obtained from a reputable source and used at low passage number to avoid discrepant results. Deficiency of miR-122 expression in HepG2 cells may be related to a relative deficiency of accessible promoter chromatin in HepG2 versus Huh-7 cells.</p></div

Cloned pre-mir-122 stem-loop region sequences from HepG2 DNA show two different haplotypes.

<p>(A) Cloned DNA sequences obtained after amplification with Taq polymerase. Two haplotypes (differently shaded) were observed for HepG2, consistent with the presence of two alleles across this region. However, among the eight HepG2 and Huh-7 clones, six sequence differences to the reference genome assembly were detected (*), so cloning was repeated using a proofreading DNA polymerase. (B) Cloned DNA sequences obtained after amplification with Phusion high fidelity DNA polymerase. Essentially the same two haplotypes of HepG2 were seen, but three novel single nucleotide substitution variants were detected and in a fourth clone, the rs9966765 allele did not correspond to the background haplotype observed. The reported error rate of Phusion High-Fidelity DNA Polymerase (GC Buffer) is 9.5 x 10^-7 errors / base pair / PCR cycle (New England Biolabs). SNPs rs9966765 and rs1135519 are located upstream of the pre-mir-122 stem-loop region; their respective alleles are shown. The genomic positions on chromosome 18 (GRCh37/hg19 (Feb. 2009) human genome assembly) of non-SNP sequence variants and the alleles observed are shown; (T)_n refers to the length (base pairs) of the polymorphic poly(T) tract. *, position showing a sequence variant not corresponding to the predominant haplotypes observed.</p