Chiral separation of beta-blockers after derivatization with (-)-alphamethoxy-alpha-(trifluoromethyl)phenylacetyl chloride by gas chromatography

Gas chromatographic method was investigated for the chiral separation of several beta-blockers(atenolol, betaxolol, bisoprolol, metoprolol and pindolol) using (-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride as a chiral derivatizing agent for amino group. Prior to N-acylation, hydroxyl group was converted into O-silyl ethers by react with N-methyl-N-(trimethylsilyl)trifluoroacetamide. The reaction was selective and rapid and the diastereomeric derivatives were well separated by capillary gas chromatography. (R)-isomers were eluted faster than (S)-isomers when (-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride was used as the chiral derivatizing agent. But in the opposite sequence when (+)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride was used. No racemization was found during the reaction.

Physiological and biochemical characteristics of poly gamma-glutamate synthetase complex of Bacillus subtilis

An enzymatic system for poly gamma-glutamate (PGA) synthesis in Bacillus subtilis, the PgsBCA system, was investigated. The gene-disruption experiment showed that the enzymatic system was the sole machinery of PGA synthesis in B. subtilis. We succeeded in achieving the enzymatic synthesis of elongated PGAs with the cell membrane of the Escherichia coli clone producing PgsBCA in the presence of ATP and D-glutamate. The enzyme preparation solubilized from the membrane with 8 mM Chaps catalyzed ADP-forming ATP hydrolysis only in the presence of glutamate; the D-enantiomer was the best cosubstrate, followed by the L-enantiomer. Each component of the system, PgsB, PgsC, and PgsA, was translated in vitro and the glutamate-dependent ATPase reaction was kinetically analyzed. The PGA synthetase complex, PgsBCA, was suggested to be an atypical amide ligase.

Interaction of the Srb10 kinase with Sip4, a transcriptional activator of gluconeogenic genes in Saccharomyces cerevisiae

Sip4 is a Zn(2)Cys(6) transcriptional activator that binds to the carbon source-responsive elements of gluconeogenic genes in Saccharomyces cerevisiae. The Snf1 protein kinase interacts with Sip4 and regulates its phosphorylation and activator function in response to glucose limitation; however, evidence suggested that another kinase also regulates Sip4. Here we examine the role of the Srb10 kinase, a component of the RNA polymerase II holoenzyme that has been primarily implicated in transcriptional repression but also positively regulates Gal4. We show that Srb10 is required for phosphorylation of Sip4 during growth in nonfermentable carbon sources and that the catalytic activity of Srb10 stimulates the ability of LexA-Sip4 to activate transcription of a reporter. Srb10 and Sip4 coimmunoprecipitate from cell extracts and interact in two-hybrid assays, suggesting that Srb10 regulates Sip4 directly. We also present evidence that the Srb10 and Snf1 kinases interact with different regions of Sip4. These findings support the view that the Srb10 kinase not only plays negative roles in transcriptional control but also has broad positive roles during growth in carbon sources other than glucose.

A purified inactivated Japanese encephalitis virus vaccine made in Vero cells

A second generation, purified, inactivated vaccine (PIV) against Japanese encephalitis (JE) virus was produced and tested in mice where it was found to be highly immunogenic and protective. The JE-PIV was made from an attenuated strain of JE virus propagated in certified Vero cells, purified, and inactivated with formalin. Its manufacture followed current GMP guidelines for the production of biologicals. The manufacturing process was efficient in generating a high yield of virus, essentially free of contaminating host cell proteins and nucleic acids. The PIV was formulated with aluminum hydroxide and administered to mice by subcutaneous inoculation. Vaccinated animals developed high-titered JE virus neutralizing antibodies in a dose dependent fashion after two injections. The vaccine protected mice against morbidity and mortality after challenge with live, virulent, JE virus. Compared with the existing licensed mouse brain-derived vaccine, JE-Vax, the Vero cell-derived JE-PIV was more immunogenic and as effective as preventing encephalitis in mice. The JE-PIV is currently being tested for safety and immunogenicity in volunteers.

Chiral separation of beta2-agonists by capillary electrophoresis using hydroxypropyl-alpha-cyclodextrin as a chiral selector

Enantiomers of five racemic beta2-agonists were investigated by capillary electrophoresis employing a hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The effects of the concentration of HP-beta-CD added to the background electrolyte and of the pH of the buffer on the effective mobility and resolution of the studied compounds were examined. Very good resolution was achieved for terbutaline and clenbuterol; salbutamol and bambuterol was able to be partially resolved. Enantioselectivity and resolution were influenced by the concentration of the HP-beta-CD, buffer composition and pH.

Odontogenic keratocyst: Review of 256 cases for recurrence and clinicopathologic parameters

Odontogenic keratocyst (OKC) is of particular interest because of its high recurrence rate and aggressive behavior. Two hundred fifty-six cases of OKC were reviewed for the age of the patient at diagnosis, sex of the patient, OKC location, and radiographic findings, and 132 patients with OKC were observed to estimate recurrence, which was analyzed for age, sex, location, and several histopathologic findings. OKCs occurred more frequently in men (58.6%) than in women (41.4%), and they occurred in patients within a wide age range, most commonly in patients in the third decade of life (28.9%), followed by those in the second decade (25.0%); the mean age of patients with OKC was 30.8 years. One hundred ninety-six of the 256 cases (76.5%) occurred in the mandible, and the other 60 cases (23.5%) occurred in the maxilla. The mandibular molar and the premolar areas (51.2%) were the most common sites, and the most frequent clinical manifestations at first admission were swelling, pain, or both (82.4% of total cases). Radiographic impressions included dentigerous cyst (27.3%), OKC (25.4%), primordial cyst (14.8%), ameloblastoma (11.7%), residual cyst (9.8%), and radicular cyst (3.1%). The frequency of recurrence at the follow-up examination was 58.3%. There was no significant difference in the recurrence rate on the basis of the sex of the patient. However, OKCs had a significantly higher recurrence rate in patients in the fifth decade of life than in patients in the other age groups (P = .005).Recurrence rates were significantly dependent on the sites of involvement, and OKCs in the mandibular molar region had significantly higher recurrence rates than those in other sites (P = .001). The histopathologic presence of one or more daughter cysts was significantly related to recurrence (P = .03).

Evaluation of the anti-tumor and anti-angiogenic effect of paclitaxel and thalidomide on the xenotransplanted oral squamous cell carcinoma

Angiogenesis is an essential process for the growth and invasion of cancer. However, it is uncertain that anti-angiogenic effects can be a major treatment strategy of oral cancer. The aim of this study was to investigate whether thalidomide and paclitaxel, which are known to be potent inhibitors of angiogenesis, have inhibitory effects on the growth of oral squamous cell carcinoma (OSCC) xenotransplanted into nude mice and whether anti-angiogenesis can be included as a major treatment strategy of oral cancer. After human OSCC cell line, KB, was subcutaneously inoculated into 32 nude mice, the volume of tumor was measured every 3 days. When the tumor mass reached 300-500 mm3, thalidomide (200 mg/kg) and paclitaxel (13 mg/kg) were administered into the animals and tumor volume change was checked. The excised tumor masses on the 30th day after administration were frozen and processed for immunohistochemistry using vascular endothelial growth factor (VEGF) and CD31, and for real-time reverse transcription-polymerase chain reaction (RT-PCR). We evaluated VEGF expression and the expression of its mRNA and CD31 for vessel density. Paclitaxel showed an inhibitory effect on the growth of transplanted human OSCC and reduced the immunohistochemical expression of VEGF and CD31 and VEGF mRNA (P<0.01). Thalidomide also lowered remarkably VEGF expression (P<0.01) and CD31 (P<0.01) as well as VEGF mRNA (P<0.05), but it did not show statistically significant inhibitory effect on the tumor growth. These results suggest that the growth of human OSCC is not simply dependent on VEGF-induced angiogenesis and that anti-angiogenic therapy alone is not likely to be effective for the treatment of OSCC, but might be regarded as adjuvant chemotherapeutic strategy.

Enantiomeric purity test of bevantolol by reversed-phase high performance liquid chromatography after derivatization with 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate

A reversed-phase high-performance liquid chromatographic method was developed to determine the optical purity of bevantolol enantiomers. (S)-(-)-Menthyl chloroformate((-)-MCF), (S)-(-)-alpha-methylbenzyl isocyanate((-)-MBIC) and 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate(GITC), which can react with the secondary amine group of bevantolol were investigated as chiral derivatization reagents. Among them indirect chiral HPLC method using GITC gave the best result. The derivatization proceeded quantitatively within 20 min at room temperature. Separation of the enantiomers as diastereomers was achieved by reversed-phase HPLC within 20min using ODS column. Different ratios of (S)-(-)-bevantolol and (R)-(+)-bevantolol were prepared. Enantiomeric separation of these mixtures took place on a chiralcel OD column or, after derivatization with GITC, on a ODS column. No racemization was found during the experiment. This method allowed determination of 0.05% of either enantiomer in the presence of its stereoisomer and method validation showed adequete linearity over the required range.

A high glucose concentration stimulates the expression of monocyte chemotactic peptide 1 in human mesangial cells

The mechanism of glomerular infiltration of monocytes remains unknown in diabetic nephropathy. We examined the effect of a high glucose concentration on monocyte chemotactic peptide 1 (MCP-1) expression in human mesangial cells (MCs) by using enzyme-linked immunosorbent assay and reverse transcription coupled with polymerase chain reaction (PCR). More than a 50% increase in the MCP-1 protein production was observed in MCs cultured in high-glucose medium (450 mg/dl) as compared to normal glucose (100 mg/dl; 1,496 +/- 75 vs. 966 +/- 15 pg/ml after 24 h, 1,910 +/- 93 vs. 1,250 +/- 55 pg/ml after 48 h). Semiquantitative PCR showed that phorbol myristate acetate (100 nM) increased the ratio of PCR products for MCP-1 to housekeeping gene glyceraldehyde-3-phosphate dehydrogenase on densitometric results at 24 h by 2.7-fold, which was prevented by calphostin C (200 nM) pretreatment. High glucose increased the ratio by 3-fold as compared to normal glucose at 24 h (0.72 +/- 0.11 vs. 0.24 +/- 0.01). This was also suppressed by calphostin C pretreatment. These findings demonstrate that high glucose can directly increase MCP-1 expression in MCs, which may contribute to monocyte infiltration in diabetic nephropathy, and this is regulated by protein kinase C.

Regulation of the balance of one-carbon metabolism in Saccharomyces cerevisiae

One-carbon metabolism in yeast is an essential process that relies on at least one of three one-carbon donor molecules: serine, glycine, or formate. By a combination of genetics and biochemistry we have shown how cells regulate the balance of one-carbon flow between the donors by regulating cytoplasmic serine hydroxymethyltransferase activity in a side reaction occurring in the presence of excess glycine. This control governs the level of 5,10-methylene tetrahydrofolate (5,10-CH(2)-H(4)folate) in the cytoplasm, which has a direct role in signaling transcriptional control of the expression of key genes, particularly those encoding the unique components of the glycine decarboxylase complex (GCV1, GCV2, and GCV3). Based on these and other observations, we propose a model for how cells balance the need to supplement their one-carbon pools when charged folates are limiting or when glycine is in excess. We also propose that under normal conditions, cytoplasmic 5,10-CH(2)-H(4)folate is mainly directed to generating methyl groups via methionine, whereas one-carbon units generated from glycine in mitochondria are more directed to purine biosynthesis. When glycine is in excess, 5, 10-CH(2)-H(4)folate is decreased, and the regulation loop shifts the balance of generation of one-carbon units into the mitochondrion.

Determination of terbutaline enantiomers in human plasma by coupled achiral-chiral high performance liquid chromatography

Achiral-chiral column switching HPLC assay was developed to allow the separation and quantification of the enantiomers of terbutaline in human plasma by means of fluorescence detection. Plasma samples were prepared by solid-phase extraction with sep-pak silica, followed by HPLC assay. The enantiomers of terbutaline and the internal standard were separated from the biological matrix on a silica column, and the two enantiomers were resolved and quantified on a Sumichiral OA-4900 column. The two columns were connected by a switching valve equipped with silica trap column. The trap column was used to concentrate the terbutaline in the eluent from the achiral column before back flushing onto the chiral phase. For each enantiomers, the assay was linear between 2.5-125 ng/ml (r=0.9999) and detection limit was 1.0 ng/ml.

Reproducibility of gastric myoelectrical activity and the water load test in patients with dysmotility-like dyspepsia symptoms and in control subjects

Gastric dysrhythmias and normal gastric myoelectrical activity have been recorded in patients with functional dyspepsia. The aim of this study was to determine the reproducibility of gastric myoelectrical patterns and responses to a water load in patients with dysmotility-like functional dyspepsia and healthy control subjects. We studied 24 patients with dysmotility-like functional dyspepsia and 24 age-matched control subjects. Gastric myoelectrical activity was assessed using cutaneous electrodes to record electrogastrograms (EGGs) before and after the subjects ingested water until full. The EGGs with water load tests were repeated 1 week apart. The patients ingested significantly smaller volumes of water at both week 1 and 2 (358 +/- 26 mL and 349 +/- 30 mL) compared to control subjects (557 +/- 35 mL and 560 +/- 27 mL, p < 0.01). Gastric dysrhythmias were found in 4 of 24 (16.7%) control subjects at each visit and in 14 (58%) and 12 (50%) of the dyspeptic patients at week 1 and 2, respectively. Of 14 patients, 2 (14.3%) had gastric dysrhythmias at week 1 but had normal gastric rhythms at week 2. Thus, reproducibility was 100% in the control subjects and 91.7% in the patients. In conclusion, some variability in EGG pattern occurred, but gastric myoelectrical activity and responses to the water load test were generally consistent and reproducible in patients with dysmotility-like functional dyspepsia and in healthy control subjects.

Quantitative determination of salidroside and tyrosol from the underground part of Rhodiola rosea by high performance liquid chromatography

A reversed-phase high performance liquid chromatographic method was developed to determine salidroside and tyrosol simultaneously in the Rhodiola rosea. The optimum condition was Nova-Pak C18 as stationary phase, 6.5% methanol in water as mobile phase and detection at UV 225 nm. The identification was carried out by comparing the retention time and IC/MS spectrum of the relevant peaks with those of isolated standards. The contents of salidroside and tyrosol in the samples gathered from various area in China were ranged over 1.3-11.1 mg/g and 0.3-2.2 mg/g, respectively.

A novel microbial interaction: obligate commensalism between a new gram-negative thermophile and a thermophilic Bacillus strain

Obligately commensal interaction between a new gram-negative thermophile and a thermophilic Bacillus strain was investigated. From compost samples, a mixed culture showing tyrosine phenol-lyase activity was enriched at 60 degrees C. The mixed culture consisted of a thermophilic gram-negative strain, SC-1, and a gram-positive spore-forming strain, SK-1. In mixed cultures, strain SC-1 started to grow only when strain SK-1 entered the stationary phase. Although strain SC-1 showed tyrosine phenol lyase activity, we could not isolate a colony with any nutrient medium. For the isolation and cultivation of strain SC-1, we added culture supernatant and cell extract of the mixed culture to the basal medium. The supernatant and cell extract of the mixed culture contained heat-stable and heat-labile factors, respectively, that are essential to the growth of strain SC-1. During pure cultures of strain SK-1, the heat-stable growth factors were released during the growth phase and the heat-labile growth factors were produced intracellularly at the early stationary phase. Strain SC-1 was gram-negative and microaerophilic, and grows optimally at 60 degrees C. Based on these results, we propose a novel commensal interaction between a new gram-negative thermophile, strain SC-1, and Bacillus sp. strain SK-1.

Chiral separation of the enantiomers of metoprolol and its metabolites by high performance liquid chromatography

(1'R, 2R)-, (1'R, 2S)-, (1'S, 2R)- and (1'S, 2S)-alpha-hydroxymetoprolol; (2R)- and (2S)-O-desmethylmetoprolol; and (2R)- and (2S)-metoprolol acid are major metabolites of (2R)-and (2S)-metoprolol, beta-adrenergic antagonist. The focus of most chiral separation methods until now has been on determination of the enantiomeric parent drug. However, it is just as important to be able to follow the metabolism of the enantiomers and their possible chiral metabolites. Therefore, for the study of stereoselective metabolism and pharmacokinetics of metoprolol, the chiral separation of the enantiomers of metoprolol and its metabolites has been investigated using four chiral stationary phases, i.e., Chiralcel OD, Chiral-AGP, Cyclobond I and Sumichiral OA-4900 columns. Metoprolol acid was resolved only by Sumichiral OA-4900. Chiralcel OD provided the highest separation factor and resolution value for metoprolol and O-desmethylmetoprolol and partially resolved the four stereoisomers of alpha-hydroxymetoprolol. Diastereomeric alpha-hydroxymetoprolols were resolved using the coupled column chromatographic system of two chiral stationary phases, Sumichiral OA-4900 column and Chiralcel OD column.

Expression of matrix metalloproteinase-2 and -9 in oral squamous cell carcinomas with regard to the metastatic potential

In order to evaluate the significance of matrix metalloproteinases (MMPs) in predicting the metastatic potential of oral squamous cell carcinomas (SCCs), we compared MMP-2 and -9 expression in 19 metastasizing oral SCCs with that in 25 non-metastasizing cases by immunohistochemistry and gelatin zymography. Immunohistochemistry showed that increased MMP-2 expression was not significantly related to metastasis; increased MMP-9 expression found in oral SCCs was, however, statistically significant (oral SCCs with metastasis, 73.7%; those without metastasis, 36.0%; P<0.05). Gelatin zymography revealed no significant difference in the activated form of MMP-2 between metastasizing and non-metastasizing oral SCCs. In metastasizing SCCs, on the other hand, increases in the activated form of MMP-9 were significant. These results suggest that oral SCCs express MMP-2 and -9, and that MMP-9 may play a more important role than MMP-2 in the metastasis of oral SCCs to adjacent tissue. An analysis of MMP-9 expression may be useful for predicting the metastatic potential of oral SCCs.

Reversed-phase high performance liquid chromatographic separation of the enantiomers of terbutaline by derivatization with 2,3,4,6-tetra-o-acetyl-beta-D-glucopyranosyl isothiocyanate

The enantiomers of the bronchodilator terbutaline were separated by reversed-phase high performance liquid chromatography after derivatization with 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate(GITC) reagent. The derivatization proceeded quantitatively within 1 h at room temperature. The corresponding diastereomeric thiourea derivatives were well resolved on an ODS column with acetonitrile-acetate buffer as a mobile phase. Elution orders of the diastereomers were confirmed by derivatization of R-(-)-terbutaline and S-(+)-terbutaline which were collected by semi-preparative chiral HPLC using Sumichiral OA-4700 column. The native fluorescence of terbutaline was quenched by derivatization with GITC. The detection limit was 25 ng when monitored at UV 278 nm.

Chiral separation of beta-blockers after derivatization with (-)-menthyl chloroformate by reversed-phase high performance liquid chromatography

Optimum conditions of chiral derivatization reaction of beta-blockers acebutolol, arotinolol, beta-xolol, bisoprolol, celiprolol, metoprolol and pindolol) with (-)-menthyl chloroformate were investigated for the resolution by HPLC. With more than 30 times molar excess of (-)-menthyl chloroformate chiral derivatization reactions were completed within one hour at room temperature except arotinolol and celiprolol. Diastereomeric derivatives of beta-blockers were well resolved on the ODS column using acetonitrile-methanol-water as a mobile phase.

Chiral purity test of metoprolol enantiomer after derivatization with (-)-menthyl chloroformate by reversed-phase high performance liquid chromatography

A reversed-phase high-performance liquid chromatographic method was developed to determine the optical purity of metoprolol enantiomers. The enantiomers were converted to diastereomeric derivatives using (-)-menthyl chloroformate reagent. Separation of the enantiomers as diastereomers was achieved by reversed-phase HPLC within 30 min using Inertsil C8 column. This method allowed determination of 0.05% of either enantiomer in the presence of its stereoisomer and method validation showed adequate linearity over the required range. Owing to the reaction condition during the derivatization with (-)-menthyl chloroformate, the possibility of racemization had to be established. Different ratios of (S)-(-)-metoprolol and (R)-(+)-metoprolol were prepared. Enantiomeric separation of these mixtures took place on a chiralcel OD column or, after derivatization with (-)-menthyl chloroformate, on a C8 column. The results from the these two independent separation systems were compared with trace racemization and were in very good agreement. No racemization was found during the experiment.

Improved fluorescent determination method of cellular sphingoid bases in high-performance liquid chromatography

Precolumn orthophthaldehyde (OPA) labeling method of sphingoid bases, sphingosine and sphinganine, was investigated to obtain high fluorescent detectability. In order to improve the fluorescent yield, we investigated the optimal solubility of sphingoid bases for five pre-incubation solvents by incorporating the heating procedure before OPA derivatization. The pre-incubation in ethanol prominently increased the fluorescent peak height of OPA derivative for each sphingoid bases in high performance liquid chromatography. About ten-fold increase of detectability was archived by pre-incubating lipid extracts pellets in ethanol at 60 degrees C for 30 min. Optimal derivatization was performed in 30 min at ambient temperature and the fluorescent intensity of OPA derivative was stable for two weeks at 4 degrees C. The detection limit of sphingosine was 0.1 pmol as injected amount. This method was applied to the determination of cellular sphingosine and sphinganine in various human lung cancer cells. This OPA procedure was prospective to be useful for quantitating the amount of sphingoid bases in other cancer cells.

Control of expression of one-carbon metabolism genes of Saccharomyces cerevisiae is mediated by a tetrahydrofolate-responsive protein binding to a glycine regulatory region including a core 5'-CTTCTT-3' motif

Expression of yeast genes involved in one-carbon metabolism is controlled by glycine, by L-methionine, and by nitrogen sources. Here we report a novel control element containing a core CTTCTT motif mediating the glycine response, demonstrating that a protein binds this element, that binding is modulated by tetrahydrofolate, and that folate is required for the in vivo glycine response. In an heterologous CYC1 promoter the region needed for the glycine response of GCV2 (encoding the P-subunit of glycine decarboxylase) mediated repression that was relieved by glycine. It was also responsible for L-methionine control but not nitrogen repression. GCV1 and GCV3 have an homologous region in their promoters. The GCV1 region conferred a glycine response on an heterologous promoter acting as a repressor or activator depending on promoter context. A protein was identified that bound to the glycine regulatory regions of GCV1 and GCV2 only if the CTTCTT motif was intact. This protein protected a 17-base pair CATCN7CTTCTT region of GCV2 that is conserved between GCV1 and GCV2. Protein binding was increased by tetrahydrofolate, and use of a fol1 deletion mutant indicated the involvement of a folate in the in vivo glycine response. Tetrahydrofolate or a derivative may act as a ligand for the transcription factor controlling expression of one-carbon metabolism genes.

Induction of apoptosis in colon cancer cells by nonsteroidal anti-inflammatory drugs

Epidemiological studies have demonstrated that nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the incidence of colon cancer. In addition, NSAIDs reduce the number and size of polyps in patients with familial adenomatous polyposis. The mechanisms of the anti-neoplastic effect of NSAIDs are still far from complete understanding, but one possible mechanism is the induction of apoptosis. Several lines of evidence suggest that NSAIDs-induced apoptosis in colon cancer cells are mediated through the cyclooxygenase (COX)-independent pathway. In this study we explored the mechanism of NSAIDs-induced apoptosis in the colon cancer cell line, HT-29. We confirmed that NSAIDs induce apoptosis in HT-29 cells irrespective of their COX-selectivity. Indomethacin enhanced the expression of p21waf-1 in HT-29 cells. However the expression of apoptosis-related genes such as Fas, bcl-2 and bax was not affected by indomethacin. Intra- and extra-cellular calcium chelators, protein tyrosine kinase (PTK) inhibitor, protein kinase A (PKA) inhibitor and protein kinase C (PKC) inhibitors did not influence indomethacin-induced apoptosis in HT-29 cells. We concluded that NSAIDs-induced apoptosis in colon cancer cells may be independent from signals transducted through [Ca++]i, PTK, PKA, PKC or the expression of apoptosis-related genes. In contrast, our results demonstrating the induction of p21waf-1 transcription by NSAIDs suggest the possible association of NSAIDs-induced apoptosis and cell-cycle control in colon cancer cells.

Nucleotide sequence of nucleocapsid protein (N) of Hantaan virus isolated from a Korean hemorrhagic fever patient

The nucleotide sequence of the nucleocapsid protein (N) coding region of a Hantaan virus strain (CFC94-2) isolated from a Korean Hemorrhagic Fever (KHF) patient was determined by sequencing a series of deletion mutants. Comparison of the N coding sequence of CFC94-2 to the sequence of the prototype of Hantaan virus, strain 76-118 reveals a 4.97% difference in the nucleotide sequence and a 1.6% difference in the deduced amino acid sequence. The rate of amino acid sequence variation in N protein of different Hantaan viruses (1.6%) is quite similar to that in G1 and G2 envelope proteins (1.7%). These results suggest that N protein may be under a similar selection pressure to G1 and G2 envelope proteins against host immune system.