An expedient synthesis of N-protected- -tetrahydrofuranylglycine and its application in the synthesis of novel substrate based inhibitors of HIV-1 protease

Z- and Fmoc-L-tetrahydrofuranylglycines have been obtained from L-vinylglycine through dipolar cycloaddition reaction, and its Fmoc derivative has been applied in the synthesis of modified S9 and S10 substrates of HIV-1 protease. These compounds mostly acted as strong inhibitors, rather than substrates, of the protease, probably due to the favourable interactions of the tetrahydrofuranylglycine moiety at the S(2) site.     

Distribution of Rutaceae-specific Repeated Sequences Isolated from Citrus Genomes

Three clones of dispersed repetitive sequences (MCS-26a, JA-5and JB-7) were isolated from a library of PCR products amplifiedfrom Citrus DNA using primers complementary to the minisatellitecore sequences. Distribution of these repetitive sequences inthe genomic DNA was highly variable among members of the Rutaceaefamily studied here. MCS-26a was specifically amplified in thesubfamily Aurantioideae, but not in other subfamilies of theRutaceae. Different levels of JA-5 amplification were observedamong genera in the subfamily Aurantioideae. JB-7 was widelydetected throughout the Rutaceae. These data suggest that thethree repeated sequences analysed in this study were amplifiedat different stages in the evolution of Rutaceae and that theyare useful for systematic studies of the Rutaceae. In addition,the repetitive sequences displayed a high level of restrictionfragment length polymorphism (RFLP) among Citrus species andtheir relatives, suggesting that they serve as hot spots forchanges in the genome after amplification. Copyright 2001 Annalsof Botany Company Citrus, Rutaceae, repeated sequences, DNA fingerprinting, RFLP     

Carbohydrate recognition of gramicidin S analogues in aqueous medium.

We have designed and synthesized of carbohydrate-binding peptides, gramicidin S analogues. Asn/Asp/Gln and Trp residues in the peptides were employed as the binding sites for carbohydrates by hydrogen-bonding interaction and the creation units for hydrophobic pocket to promote the interaction, respectively. The data of fluorescence spectroscopy and affinity column chromatography indicated that the peptides possessed the binding ability for some carbohydrates in aqueous medium. As a result of 1H NMR study, nuclear Overhauser effects between aromatic side chains of a peptide, [Gln(1,1'),Trp(3,3')]-gramisidin S and mannose were observed, indicating that the interaction of the peptide with the sugar occurred in the hydrophobic environment formed by Trp and Phe residues.     

Capability of intensity discrimination in multiple receptor model of insect taste

A simple model in which one CNS taste neuron integrates inputsfrom multiple peripheral receptors is introduced in order toinvestigate the mechanism of acute intensity taste discriminationin flies. Information theory is applied to evaluate the acuteability of discrimination provided by the model. The presentanalysis is carried out under two statistical conditions concerningthe uncertainty of receptor response. Based on experimentaldata obtained by Smith et al. (1983), we estimate the mutualinformation entropy of the model. The numerical results obtainedhere indicate that the uncertainty observed in a single receptorresponse is dramatically reduced by the central integration.Furthermore, each of the eleven stimulus intensity levels experimentallyapplied by Smith et al., can be discriminated completely byintegrating the responses of the realistic number of receptors(33–212). Such a great improvement of the differentialsensitivity in the model resolves the discrepancy between thelow differential sensitivity of single sugar receptors (Smithet al., 1983) and the high sensitivity obtained in the feedingbehavior (Dethier and Rhoades, 1954; Dethier and Bowdan, 1984)of the blowfly.     

A Stereoselective Synthesis of N-Acetyllincosamine Derivatives

A novel synthesis of N-acetyllincosamine derivatives (3) and (14) was accomplished.     

Inhibitory effect of heavy water on mutability of chemically injured Escherichia coli cells

After E. coli cells (WP2 and WP2uvrA) were treated with chemical mutagens (methyl methanesulfonate, MMS; N-methyl-N-nitrosourea, MNU; 4-nitroquinoline 1-oxide, 4NQO) in 1/15 M phosphate buffer, the mutability of the treated cells plated on a D₂O-agar plate was compared with that plated on an ordinary H₂O-agar plate. The mutation frequency decreased more or less on the D₂O-agar plate. The D₂O-substitution effects, as termed by the relative mutation frequencies (MF_D2O/MF_H2O), are 0.92 for MMS, 0.29 for MNU, and 0.42 for 4NQO in WP2, and 0.68 for MMS, 0.49 for MNU, and 0.16 for 4NQO in WP2uvrA. The D₂O effect seemed to be partly related to the function of the uvrA gene-associated products. The pH dependence of mutability was discussed in connection with the D₂O-substitution effect.     

Discovery of orally efficacious RORγt inverse agonists. Part 2: Design,synthesis, and biological evaluation of novel tetrahydroisoquinoline derivatives

A series of tetrahydroisoquinoline derivatives were designed, synthesized, and evaluated for their potential as novel orally efficacious retinoic acid receptor-related orphan receptor-gamma t (RORγt) inverse agonists for the treatment of Th17-driven autoimmune diseases. We carried out cyclization of the phenylglycinamide core by structure-based drug design and successfully identified a tetrahydroisoquinoline carboxylic acid derivative 14 with good biochemical binding and cellular reporter activity. Interestingly, the combination of a carboxylic acid tether and a central fused bicyclic ring was crucial for optimizing PK properties, and the compound 14 showed significantly improved PK profile. Successive optimization of the carboxylate tether led to the discovery of compound 15 with increased inverse agonistic activity and an excellent PK profile. Oral treatment of mice with compound 15 robustly and dose-dependently inhibited IL-17A production in an IL23-induced gene expression assay.     

Effect of hip joint angle at seat-off on hip joint contact force during sit-to-stand movement: a computer simulation study

Background

Sit-to-stand movements are a necessary part of daily life, and excessive mechanical stress on the articular cartilage has been reported to encourage the progression of osteoarthritis. Although a change in hip joint angle at seat-off may affect hip joint contact force during a sit-to-stand movement, the effect is unclear. This study aimed to examine the effect of the hip joint angle at seat-off on the hip joint contact force during a sit-to-stand movement by using a computer simulation.

Methods

A musculoskeletal model was created for the computer simulation, and eight muscles were attached to each lower limb. Various sit-to-stand movements were generated using parameters (e.g., seat height and time from seat-off to standing posture) reported by previous studies. The hip joint contact force for each sit-to-stand movement was calculated. Furthermore, the effect of the hip joint angle at seat-off on the hip joint contact force during the sit-to-stand movement was examined. In this study, as the changes to the musculoskeletal model parameters affect the hip joint contact force, a sensitivity analysis was conducted.

Results and conclusions

The hip joint contact force during the sit-to-stand movement increased approximately linearly as the hip flexion angle at the seat-off increased. Moreover, the normal sit-to-stand movement and the sit-to-stand movement yielding a minimum hip joint contact force were approximately equivalent. The effect of the changes to the musculoskeletal model parameters on the main findings of this study was minimal. Thus, the main findings are robust and may help prevent the progression of hip osteoarthritis by decreasing mechanical stress, which will be explored in future studies.

     

High-Sensitivity and High-Resolution In Situ Hybridization of Coding and Long Non-coding RNAs in Vertebrate Ovaries and Testes

Background

Subcellular localization of coding and non-coding RNAs has emerged as major regulatory mechanisms of gene expression in various cell types and many organisms. However, techniques that enable detection of the subcellular distribution of these RNAs with high sensitivity and high resolution remain limited, particularly in vertebrate adult tissues and organs. In this study, we examined the expression and localization of mRNAs encoding Pou5f1/Oct4, Mos, Cyclin B1 and Deleted in Azoospermia-like (Dazl) in zebrafish and mouse ovaries by combining tyramide signal amplification (TSA)-based in situ hybridization with paraffin sections which can preserve cell morphology of tissues and organs at subcellular levels. In addition, the distribution of a long non-coding RNA (lncRNA), lncRNA-HSVIII, in mouse testes was examined by the same method.

Results

The mRNAs encoding Mos, Cyclin B1 and Dazl were found to assemble into distinct granules that were distributed in different subcellular regions of zebrafish and mouse oocytes, suggesting conserved and specific regulations of these mRNAs. The lncRNA-HSVIII was first detected in the nucleus of spermatocytes at prophase I of the meiotic cell cycle and was then found in the cytoplasm of round spermatids, revealing expression patterns of lncRNA during germ cell development. Collectively, the in situ hybridization method demonstrated in this study achieved the detection and comparison of precise distribution patterns of coding and non-coding RNAs at subcellular levels in single cells of adult tissues and organs.

Conclusions

This high-sensitivity and high-resolution in situ hybridization is applicable to many vertebrate species and to various tissues and organs and will be useful for studies on the subcellular regulation of gene expression at the level of RNA localization.