A CD4 mimic as an HIV entry inhibitor: Pharmacokinetics

To date, several small molecules of CD4 mimics, which can suppress competitively the interaction between an HIV-1 envelope glycoprotein gp120 and a cellular surface protein CD4, have been reported as viral entry inhibitors. A lead compound 2 (YYA-021) with relatively high potency and low cytotoxicity has been identified previously by SAR studies. In the present study, the pharmacokinetics of the intravenous administration of compound 2 in rats and rhesus macaques is reported. The half-lives of compound 2 in blood in rats and rhesus macaques suggest that compound 2 shows wide tissue distribution and relatively high distribution volumes. A few hours after the injection, both plasma concentrations of compound 2 maintained micromolar levels, indicating it might have promise for intravenous administration when used combinatorially with anti-gp120 monoclonal antibodies.     

Purification and Some properties of Endo-β-1,6-Glucanase from Acinetobacter sp.

A kind of endo-β-1, 6-glucanase has been purified from the culture filtrate of Acinetobacter sp. grown in the medium containing baker’s yeast cells as a carbon source. A 100-fold purified preparation was obtained by DEAE-Sephadex A–50 column chromatography. The enzyme hydrolyzed pustulan giving a series of gentio-oligosaccharides and glucose. Gentiotriose and gentiotetraose were hydrolyzed by this enzyme yielding glucose and gentiobiose, and glucose, gentiobiose and gentiotriose, respectively. Gentiobiose was not hydrolyzed. Baker’s yeast glucans obtained from the isolated cell walls were also hydrolyzed by this enzyme giving a series of oligosaccharides and glucose. From the action patterns on these carbohydrates, we concluded the present enzyme being endo-β-1, 6-glucanase.     

Purification and Chemical Analysis of Microbial Cell Flocculant Produced by Aspergillus sojae AJ7002

A bio-flocculant was isolated from the culture broth of Asp. sojae AJ 7002. It was partially purified by acetone or ethanol precipitation, by ion-exchange and gel chromatography, and by dialysis. The isolated polymer possessed chemical characteristics of a poly-hexosamine and a protein. Glucosamine and galactosamine were not acetylated. The flocculant contained 2-ketogluconic acid, but sulfur or phosphorus was not detected. This flocculant was thermo-stable and its activity varied with pH. It was suggested that the hexosamine moiety in the polymer played a major role in bio-flocculation, assisted by protein portion in enlargement of the molecular weight of the flocculant, and by 2-ketogluconic acid in endowing it with amphoteric character.     

Dorsal telencephalon-specific expression of Cre recombinase in PAC transgenic mice

The ability to restrict gene expression or disruption to specific regions of the brain would enhance understanding of the molecular basis for brain development and function. For this purpose, brain region-restricted promoters are essential. Here we report the isolation of a DNA fragment containing the Emx1 gene promoter, which is responsible for dorsal telencephalon-specific expression. The Cre recombinase gene was inserted into a mouse PAC (P1-derived artificial chromosome) Emx1-locus clone (PAC-Emx1#1 clone) and utilized to generate three transgenic mouse lines. In all three lines, especially Tg3, Cre-mediated recombination was highly restricted to Emx1-expressing cell lineages, from embryonic stages to adulthood. Immunohistochemical analyses showed that Cre protein is expressed in the dorsal telencephalon in all three lines in adulthood. Thus, the PAC-Emx1#1 clone contains essentially all regulatory elements necessary for Emx1 gene expression. Our results suggest that Emx1-Cre Tg3 mice and the PAC-Emx1#1 clone constitute powerful tools for dorsal telencephalon-specific gene manipulation.     

Biochemical characterization of the kink-turn RNA motif

RNA, which acts as a medium for transmitting genetic information, plays a variety of roles in a cell. As with proteins, elucidation of the three- dimensional (3D) structures of RNAs is important for understanding their various roles. Determination of the atomic structures of crystallized ribosome has enabled the identification of previously unknown RNA structural motifs. The kink-turn (K-turn or GA) motif, which causes a sharp bend in an RNA double helix, was identified as one of these structural motifs. To biochemically characterize the K-turn, the motif was inserted into a hinge region of P4-P6 RNA, which is the most extensively studied self-folding RNA, and its properties were investigated. The stability and metal ion requirement of the constructs containing three different K-turn motifs were analyzed using native PAGE and dimethyl sulfate (DMS) modification. The formation of the sharp bending structure depends on the presence of divalent cation like Mg²⁺ or Ca²⁺, although its required concentration is different for each motif.     

Expression of normal cellular prion protein (PrP(c)) on T lymphocytes and the effect of copper ion: Analysis by wild-type and prion protein gene-deficient mice

The purpose of this report was to determine the effect of prion protein (PrP) gene disruption on T lymphocyte function. Previous studies have suggested that normal cellular prion protein (PrP(c)) binds to copper and Cu(2+) is essential for interleukin-2 (IL-2) mRNA synthesis. In this study, IL-2 mRNA levels in a copper-deficient condition were investigated using T lymphocytes from prion protein gene-deficient (PrP(0/0)) and wild-type mice. Results showed that Cu(2+) deficiency had no effect on PrP(c) expression in Con A-activated splenocytes. However, a delay in IL-2 gene expression was observed in PrP(0/0) mouse T lymphocyte cultures using Con A and Cu(2+)-chelator. These results suggest that PrP(c) expression may play an important role in rapid Cu(2+) transfer in T lymphocytes. The rapid transfer of Cu(2+) in murine T lymphocytes could be one of the normal functions of PrP(c).     

Causal relationship between the loss of RUNX3 expression and gastric cancer

Runx3/Pebp2alphaC null mouse gastric mucosa exhibits hyperplasias due to stimulated proliferation and suppressed apoptosis in epithelial cells, and the cells are resistant to growth-inhibitory and apoptosis-inducing action of TGF-beta, indicating that Runx3 is a major growth regulator of gastric epithelial cells. Between 45% and 60% of human gastric cancer cells do not significantly express RUNX3 due to hemizygous deletion and hypermethylation of the RUNX3 promoter region. Tumorigenicity of human gastric cancer cell lines in nude mice was inversely related to their level of RUNX3 expression, and a mutation (R122C) occurring within the conserved Runt domain abolished the tumor-suppressive effect of RUNX3, suggesting that a lack of RUNX3 function is causally related to the genesis and progression of human gastric cancer.     

Functional vanilloid receptors in cultured normal human epidermal keratinocytes

Vanilloid receptor subtype 1, VR1, is an ion channel that serves as a polymodal detector of pain-producing chemicals such as capsaicin and protons in primary afferent neurons. Here we showed that both capsaicin and acidification produced elevations in the intracellular Ca(2+) concentration ([Ca(2+)](i)) in cultured human epidermal keratinocytes. The capsaicin- and acidification-evoked increases in [Ca(2+)](i) were inhibited by capsazepine, an antagonist to VR1. VR1-like immunoreactivity was observed in the cells. These findings suggest that functional VR1-like protein is present and functions as a sensor against noxious chemical stimuli, such as capsaicin or acidification, in epidermal keratinocytes.     

Antimicrobial activity of essential oils against Helicobacter pylori

Background. Helicobacter pylori is an important pathogen responsible for gastroduodenal diseases in humans. Although the eradication of H. pylori using antibiotics often improves gastroduodenal diseases, resistance to the antibiotics is emerging. Materials and Methods. The antimicrobial effect of essential oils and the development of resistance to the essential oils were evaluated in vitro and in vivo. Results. Thirteen essential oils used in this study completely inhibited the growth of H. pylori in vitro at a concentration of 0.1% (v/v). Cymbopogon citratus (lemongrass) and Lippia citriodora (lemon verbena) were bactericidal against H. pylori at 0.01% at pH 4.0 and 5.0. Resistance to lemongrass did not develop even after 10 sequential passages, whereas resistance to clarithromycin developed under the same conditions. In in vivo studies, the density of H. pylori in the stomach of mice treated with lemongrass was significantly reduced compared with untreated mice. Conclusions. These results demonstrate that the essential oils are bactericidal against H. pylori without the development of acquired resistance, suggesting that essential oils may have potential as new and safe agents for inclusion in anti‐H. pylori regimens.