A novel [1, 2, 4]triazolo[5,1-b]quinazoline derivative as a fluorescent probe for highly selective detection of Fe3+ ions.

A novel [1, 2, 4]triazolo[5,1-b]quinazoline fluorescent probe (VIi) for Fe3+ was developed, featuring with rapid response (< 5 s) and specific selectivity to Fe3+, low detection limit (1.3 × 10-5 M), as well as the ability to resist interference of chelating agent (e.g. EDTA). VIi-based fluorescent test paper can quickly recognize Fe3+ under irradiation at the wavelength of 365 nm. The fluorescence probe VIi has potential application prospects for the detection of Fe3+ in real circumstance.

A New Pathway for the Synthesis of Ketones from Aldehydes and Sulfonylhydrazones: Is Diazo the Key Intermediate?

A new pathway via a cyclic intermediate for the synthesis of ketones from aldehydes and sulfonylhydrazone derivatives under basic conditions is proposed. Several control experiments were performed along with analysis of the mass spectra and in-situ IR spectra of the reaction mixture. Inspired by the new mechanism, an efficient and scalable method for homologation of aldehydes to ketones was developed. A wide variety of target ketones were obtained in yields of 42-95 % by simply heating the 3-(trifluoromethyl)benzene sulfonylhydrazones (3-(Tfsyl)hydrazone) for 2 h at 110 °C with aldehydes and with K2 CO3 and DMSO as base and solvent, respectively.

Synthesis of 19-hydroxyprogesterone and insights into the ring-opening mechanism of the 6,19-epoxy bridge.

An efficient and scalable process for the synthesis of 19-hydroxyprogesterone was obtained through seven steps with 34.5% total yield, which is much higher than the process reported in the literature (11.0% total yield). The plausible ring-opening mechanism of 6,19-epoxy bridge in compound 7 was first proposed and the structures of intermediates were supported by the LC-MS analysis of the reaction mixture.

Antiviral Activity of Dual-acting Hydrocarbon-stapled Peptides against HIV-1 Predominantly Circulating in China.

OBJECTIVE: New rationally designed i,i+7-hydrocarbon-stapled peptides that target both HIV-1 assembly and entry have been shown to have antiviral activity against HIV-1 subtypes circulating in Europe and North America. Here, we aimed to evaluate the antiviral activity of these peptides against HIV-1 subtypes predominantly circulating in China. METHODS: The antiviral activity of three i,i+7-hydrocarbon-stapled peptides, NYAD-36, NYAD-67, and NYAD-66, against primary HIV-1 CRF07_BC and CRF01_AE isolates was evaluated in peripheral blood mononuclear cells (PBMCs). The activity against the CRF07_BC and CRF01_AE Env-pseudotyped viruses was analyzed in TZM-bl cells. RESULTS: We found that all the stapled peptides were effective in inhibiting infection by all the primary HIV-1 isolates tested, with 50% inhibitory concentration toward viral replication (IC50) in the low micromolar range. NYAD-36 and NYAD-67 showed better antiviral activity than NYAD-66 did. We further evaluated the sensitivity of CRF01_AE and CRF07_BC Env-pseudotyped viruses to these stapled peptides in a single-cycle virus infectivity assay. As observed with the primary isolates, the IC50s were in the low micromolar range, and NYAD-66 was less effective than NYAD-36 and NYAD-67. CONCLUSION: Hydrocarbon-stapled peptides appear to have broad antiviral activity against the predominant HIV-1 viruses in China. This finding may provide the impetus to the rational design of peptides for future antiviral therapy.

Distinctive Drug-resistant Mutation Profiles and Interpretations of HIV-1 Proviral DNA Revealed by Deep Sequencing in Reverse Transcriptase.

OBJECTIVE: To investigate distinctive features in drug-resistant mutations (DRMs) and interpretations for reverse transcriptase inhibitors (RTIs) between proviral DNA and paired viral RNA in HIV-1-infected patients. METHODS: Forty-three HIV-1-infected individuals receiving first-line antiretroviral therapy were recruited to participate in a multicenter AIDS Cohort Study in Anhui and Henan Provinces in China in 2004. Drug resistance genotyping was performed by bulk sequencing and deep sequencing on the plasma and whole blood of 77 samples, respectively. Drug-resistance interpretation was compared between viral RNA and paired proviral DNA. RESULTS: Compared with bulk sequencing, deep sequencing could detect more DRMs and samples with DRMs in both viral RNA and proviral DNA. The mutations M184I and M230I were more prevalent in proviral DNA than in viral RNA (Fisher's exact test, P<0.05). Considering 'majority resistant variants', 15 samples (19.48%) showed differences in drug resistance interpretation between viral RNA and proviral DNA, and 5 of these samples with different DRMs between proviral DNA and paired viral RNA showed a higher level of drug resistance to the first-line drugs. Considering 'minority resistant variants', 22 samples (28.57%) were associated with a higher level of drug resistance to the tested RTIs for proviral DNA when compared with paired viral RNA. CONCLUSION: Compared with viral RNA, the distinctive information of DRMs and drug resistance interpretations for proviral DNA could be obtained by deep sequencing, which could provide more detailed and precise information for drug resistance monitoring and the rational design of optimal antiretroviral therapy regimens.

Cellular microRNA let-7c inhibits M1 protein expression of the H1N1 influenza A virus in infected human lung epithelial cells.

The influenza virus (IV) triggers a series of signalling events inside host cells and induces complex cellular responses. Studies have suggested that host factors play an essential role in IV replication. MicroRNAs (miRNAs) represent a class of small non-coding RNAs that target mRNAs, triggering either translation repression or RNA degradation. Emerging research suggests that host-derived cellular miRNAs are involved in mediating the host-IV interaction. Using miRNA microarrays, we identified several miRNAs aberrantly expressed in IV-infected human lung epithelial cells (A549). Specifically, miR-let-7c was highly up-regulated in IV-infected A549 cells. PITA and miRanda database screening indicated that the let-7c seed sequence is a perfect complementary sequence match to the 3' untranslated region (UTR) of viral gene M1 (+) cRNA, but not to PB2 and PA. As detected by a luciferase reporter system, let-7c directly targeted the 3'-UTR of M1 (+) cRNA, but not PB2 and PA. To experimentally identify the function of cellular let-7c, precursor let-7c was transfected into A549 cells. Let-7c down-regulated IV M1 expression at both the (+) cRNA and protein levels. Furthermore, transfection with a let-7c inhibitor enhanced the expression of M1. Therefore, let-7c may reduce IV replication by degrading M1 (+) cRNA. This is the first report indicating that cellular miRNA regulates IV replication through the degradation of viral gene (+) cRNA by matching the 3'-UTR of the viral cRNA. These findings suggest that let-7c plays a role in protecting host cells from the virus in addition to its known cellular functions.

Analysis of synonymous codon usage bias in 09H1N1.

A novel subtype of influenza A virus 09H1N1 has rapidly spread across the world. Evolutionary analyses of this virus have revealed that 09H1N1 is a triple reassortant of segments from swine, avian and human influenza viruses. In this study, we investigated factors shaping the codon usage bias of 09H1N1 and carried out cluster analysis of 60 strains of influenza A virus from different subtypes based on their codon usage bias. We discovered that more preferentially used codons of 09H1N1 are A-ended or U-ended, and the intra-genomic codon usage bias of 09H1N1 is quite low. Base composition constraint, dinucleotide biases and translational selection are the main factors influencing the codon usage bias of 09H1N1. At the genome level, we find that the codon usage bias of 09H1N1 is similar to H1N1 (A/swine/Kansas/77778/2007H1N1), H9N2 from Asia, H1N2 from Asia and North America and H3N2 from North America. Our results provide insight for understanding the processes governing evolution, regulation of gene expression, and revealing the evolution of 09H1N1.

[The effects of calmodulin on the lipid-binding activity of CaM-binding protein-10 and maize non-specific lipid transfer protein].

Fluorescence-marked lipid binding experiment shows that CaMBP-10 has typical lipid binding feature of non-specific lipid transfer protein (nsLTP). We have compared the effects of calmodulin (CaM) on the lipid-binding activity of CaMBP-10 and maize nsLTP. Different influences were found in the presence of either Ca(2+) or EGTA. W-7 and TFP could abolish the influence of CaM. Therefore, it is suggested that CaM could interact specifically with both CaMBP-10 and maize nsLTP. Probably, there are different CaM regulatory mechanisms between CaMBP-10 and maize nsLTP.

[Cloning and expression of cDNA for maize nonspecific lipid transfer protein as well as calmodulin-binding activity analysis of the expression product].

Maize nonspecific lipid transfer protein (Zm-nsLTP) was cloned and expressed to investigate its CaM-binding activity. The cDNA of Zm-nsLTP was amplified using RT-PCR (Fig.1), and then inserted into the vector pET32a(+). The recombinant vector pET-Zm-nsLTP was expressed in E. coli BL21(DE3)trxB(-). Results of CaM-gel overlay assays (Fig.2) and CaM-sepharose pull-down experiments (Fig.3) indicated that recombinant Zm-nsLTP was bound to CaM in a Ca(2+)-independent manner, which is in accordance with the way that CaMBP-10 and Arabidopsis non-specific lipid transfer protein-1 (At-nsLTP1) are bound to CaM. The CaM-binding domain in Zm-nsLTP was mapped to the region of 47-60 amino acids (Fig.3), and online sequence analysis using Predict Protein program predicted that it has a BAA structure (Fig.4,5).