Effects of rhubarb on isolated gastric muscle strips of guinea pigs

AIM:To study the effects of rhubarb (dried root of Rheum officinale Baill.) on contractile activity of isolated gastric muscle strips of guinea pigs and its possible mechanism. METHODS: A total of 48 guinea pigs were killed to remove the whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parallel to the circular fibers, muscle strips were cut from the body. Each isolated gastric muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution, constantly warmed by water jacket at 37℃ and bubbled continuously with a mixed gas of 950 mL/L O2 and 50 mL/L CO2. After being incubated for 1 h with 1 g tension, rhubarb of varied concentrations (1%, 2%, 7%, 20% and 70%) was added cumulatively into the tissue chamber at intervals of 2 min. Atropine (10-6 mol/L) or isoptin (5x10-8 mol/L) or hexamethonium (10-5 mol/L) was given 2 min before the administration of rhubarb. The isometrical response was measured with an ink-writing recorder. RESULTS: Rhubarb dose dependently increased the resting tension of gastric body circular muscle (CM) (r = 0.726, P<0.05). Atropine (r= 0.829, A:0.05), isoptin (r= 0.764, A;0.05) and hexamethonium (r = 0.797, P<0.05) did not affect its action in a dose-related manner. Atropine apparently reduced the increasing action of 1%, 3%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Isoptin inhibited the effect of 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Hexamethonium reduced the increasing action of 1%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Rhubarb increased the contractile frequency of CM of body. While atropine, isoptin and hexamethonium did not inhibit the contractile frequency of gastric body CM in comparison with rhubarb at the same concentration, rhubarb at the highest concentration (100%) decreased the mean contractile amplitude of gastric body CM. Atropine, isoptin and hexamethonium did not affect the mean contractile amplitude of gastric body CM compared to rhubarb at the same concentration. CONCLUSION: Rhubarb has exciting actions on isolated gastric smooth muscle strips of guinea pig. The exciting action of rhubarb is partly mediated via cholinergic M receptor, cholinergic N receptor and L-type calcium channel.

Changes of Expressions of VEGF, bFGF, and Angiogenesis, and Effect of Benazepril, bFGF on Angiogenesis in Acute Myocardial Infarction Model of the Rabbits

Objective To explore the changes of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and angiogenesis, and the effects of bFGF, angiotensin converting enzyme inhibiter(ACEI) benazepril on the angiogenesis in acute myocardial infarction (AMI) model of rabbits, and to provide a probable evidence for the treatment of AMI. Methods AMI model was established by ligating anterior descending branch of coronary artery of Japan-Sino hybridization white rabbits. The postoperative rabbits were randomly divided into 6 groups and each group was treated with different drugs. Groups 1 and 2 were treated with normal saline (NS) for 28 and 14 days (d), group 3 and 4 with bFGF for 28 and 14 d, groups 5 with benazepril for 14 d, and group 6 with benazepril and bFGF for 14 d respectively. The rabbits were killed on the 14th or 28th d and their hearts were excised, sectioned and stained with HE, Masson trichrome to observe VEGF, bFGF and CD34 under a microscope, which were quantified with a computer-assisted morphometry. Results Compared with group 1, the granulation tissue of infarction zone (IZ) in group 2 freshened up, and the capillary density (CD) in IZ was increased (P=0.002). The CD in the IZ as well as VEGF and bFGF in groups 3 and 4 were increased respectively (P=0.011-0.037). In group 5 the changes of VEGF and bFGF were not found in the IZ and the border zone (BZ) while CD was significantly increased (35.4% and 25.6%, P=0.036 and 0.037). Compared with group 2, the CD in the IZ and BZ of group 6 was significantly increased (63.4% and 44.3% P=0.007 and 0.007), meanwhile VEGF and bFGF were increased. Compared with group 5, only VEGF was increased. Conclusion Intravenous bFGF may increase VEGF and bFGF significantly, thus promoting the angiogenesis in the IZ and BZ in cardiac infarction as VEGF and bFGF are the potent angiogenic growth factors. Benazepril may promote angiogenesis in the IZ and BZ in cardiac infarction, but its mechanism is irrelative to the expression of VEGF and bFGF. The combination of benazepril and bFGF may promote, to some extent, the expression of VEGF and bFGF, but their effect on angiogenesis has not been found.

Effect of rhubarb on contractile response of gallbladder smooth muscle strips isolated from guinea pigs

AIM: To investigate the effect of rhubarb on contractile response of isolated gallbladder muscle strips from guinea pigs and its mechanism.METHODS: Guinea pigs were killed to remove the whole gallbladder. Two or three smooth muscle strips (8 mm×3mm) were cut along the longitudinal direction. The mucosa on each strip was carefully removed. Each longitudinal muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution (37 ℃), bubbled continuously with 950 mL/L O2 and 50 mL/L CO2. The resting tension (g), mean contractile amplitude (mm),and contractile frequency (waves/min) were simultaneously recorded on recorders. After 2-h equilibration, rhubarb (10, 20, 70, 200, 700, 1 000 g/L) was added cumulatively to the tissue chamber in turns every 2 min to observe their effects on gallbladder.Antagonists were given 3 min before administration of rhubarb to investigate the possible mechanism.RESULTS: Rhubarb increased the resting tension (from 0 to 0.40±0.02, P＜0.001), and decreased the mean contractile amplitude (from 5.22±0.71 to 2.73±0.41,P＜0.001). It also increased the contractile frequency of the gallbladder muscle strips in guinea pigs (from 4.09±0.46to 6.08±0.35, P＜0.001). The stimulation of rhubarb on the resting tension decreased from 3.98±0.22 to 1.58±0.12by atropine (P＜0.001), from3.98±0.22 to 2.09±0.19 by verapamil (P＜0.001) and from 3.98±0.22 to 2.67±0.43by phentolamine (P＜0.005). But the effect was not inhibited by hexamethonium (P＞0.05). In addition, the action of mean amplitude and frequency was not inhibited by the above antagonists.CONCLUSION: Rhubarb can stimulate the motility of isolated gallbladder muscle strips from guinea pigs. The stimulation of rhubarb might be relevant with M receptor,Ca2+ channel and α receptor partly.

EXISTENCE OF SOLUTIONS OF A FAMILY OF NONLINEAR BOUNDARY VALUE PROBLEMS IN L^2-SPACES

By using the perturbation results of sums of ranges of accretive mappings of Calvert and Gupta(1978),the abstract results on the existence of solutions of a family of nonlinear boundary value problems in L2(Ω) are studied.The equation discussed in this paper and the methods used here are extension and complement to the corresponding results of Wei Li and He Zhen's previous papers.Especially,some new techniques are used in this paper.

Epstein-Barr virus in hepatocellular carcinogenesis

AIM: In recent years, studies have suggested that EpsteinBarr virus (EBV) is associated with HCC. The present study was to determine the prevalence of EBV in HCC patients,and whether EBV acted synergistically with hepatitis viruses in HCC carcinogenesis.METHODS: Liver tissue 115 HCC patients and 26 noncarcinoma patients were studied, Polymerase chain reaction (PCR) was performed to detect EBV BarnHI W DNA, EBV LMP1 DNA, HI3V X DNA, and HBV S DNA, Reverse transcription PCR (RT-PCR) was performed to detect HCV RNA and HDV RNA, Immunohistochemistry was performed to detect LMP1,HBsAg, HBcAg and HCV, The positive ratios were compared between HCC group and control group by X^2 test,RESULTS: Totally, 78 HCC samples whose 13-globulin DNA was positively detected by amplified PCR were selected,PCR was performed in all cases for EI3V DNA and HBV DNA,RT-PCR was performed in 18 cases for HCV RNA and HDV RNA. EBV BarnHI W and EBV LMP1 were positive in 18 and 6 cases, respectively. HBV X gene and HBV S gene were positive in 42 and 27 cases respectively. HCV was positive in one of the 18 cases, and none was positive for HDV. The positive rates were 28.2% (22 of 78) for EBV DNA (BarnHI W and/or LMP1) and 56.4% (44 of 78) for HBV DNA (X gene and/or S gene) respectively. In addition, 12 cases were positive for both EBV DNA and HBV DNA. Among the 26 cases in the control group, 2 cases were positive for EBV BarnHI W, 4 positive for HBV X gene and 3 positive for HBV S gene. The positive rates were 8.0% (2 of 26) and 23.1% (6 of 26),respectively, for EBV DNA and HBV DNA. The result of DNA sequencing of BamHI W was 100% homologous with the corresponding sequence of B95-8. There was significant difference in EBV infection rate between HCC patients and controls (X^2 = 4.622, P<0.05). The difference in HBV infection rate was also significant (X^2 = 8.681, P<0.05). However, there was no obvious correlation between HBV and EBV in HCC patients (X^2 = 0.835,/)>0.05). LMP1, HBV (HBsAg, HI3cAg) and HCV were detected positively in 25, 45 and 6 of 78 cases of HCC tissues respectively. In the 26 control cases,the corresponding positive cases were 2, 4 and O. The difference in EBV infection rate between HCC patients and control cases was statistically significant (X^2= 6.02,P<0.05). The difference in HBV infection rate was also statistically significant (X^2 = 10.03, P<0.05). In the 25 cases with positive LMP1 expression, 6 were in the nuclei of tumor cells, 9 in the cytoplasm of tumor cells and 10 in mesenchymal lymphocyte cytoplasm.CONCLUSION: The existence of EBV infection in HCC tissues suggests that EBV may be involved in the hepatocellular carcinogenesis in China. HBV infection may be a major cause of HCC. There is no correlation between EBV and HBV in the development of HCC. The prevalence of HCV infection is low in our area, and HDV appears not to play a direct role in hepatocellular carcinogenesis.

Lack of inhibitory effects of Lactic acid bacteria on 1,2-dimethylhydrazine-induced colon tumors in rats

AIM: A myriad of healthful effects has been attributed to the probiotic lactic acid bacteria, perhaps the most controversial issue remains that of anticancer activity. This study was aimed at investigating the putative anti-cancer effects of lactic acid bacteria strains on the progression of colon tumor in 1,2-dimethylhydrazine (DMH)-treated animals.METHODS: The strain of lactic acid bacteria used in this study was lactic acid bacteria NZ9000 that conformed to the characteristics of plasmid free. Sixty male Wistar rats were given subcutaneous injections of DMH at a dose of 40 mg/kg body wt or saline once a week for 10 weeks. The rats were divided into 6 experimental groups. After the last DMH injection,animals in groups 1 and 4 were gavaged with 1 mi of lactic acid bacteria at a dose of 5×109 per day or vehide until sacrifice at the end of week 22 or week 52. Animals in groups 1-3 were killed at the end of week 22 for histopathological examination.The whole period of experimental observation was 52 weeks.RESULTS: By the end of 22nd week, final average body weights of the rats treated with DMH alone and all animals receiving lactic acid bacteria were significantly decreased compared with the vehicle control (P＜0.05). No differences in tumor inridence, multiplicity, dimensions and stage in the colonic mucosa were observed among the groups. At week 52, the survival rate of the rats administered lactic acid bacteria was lower than that of the rats treated with DMH that were fed on control fluids of non-lactococcus lactis. The mean survival time of lactic acid bacteria-treated animals was 39 weeks.CONCLUSION: These results indicate that lactic acid bacteria lacks inhibitory effects on the progression of colon tumor in DMH-treated animals, and does not support the hypothesis that alteration of colonic flora may exert an influence on the progression of colon tumor.

Oxygen pressure leaching-flotation joint process for Jinbaoshan platinum group minerals

An oxygen pressure leaching-flotation joint process was proposed to treat Jinbaoshan platinum group minerals to produce a desired concentrate. The result demonstrates that leaching parameters which include particle size, stirring speed, liquid-solid ratio, and the dosage of calcium lignosulfonate, simultaneously affect the leaching rates of base metals and the recovery of platinum group metals (PGMs). The complete dissolution of base metals sulfides leads to a reduction in the amount of flotation carrier for enriching PGMs, decreasing the recovery of PGMs. The optimum leaching conditions are determined as follows: liquid-solid ratio of 10 mL/g, 73% occupancy of ore particle size below 0.043 mm, stirring speed of 400 r/min, and 0.6 g dosage of calcium lignosulfonate. Under optimal conditions, the leaching rates of Cu, Ni and Fe are 87.6%, 87.6% and 90.3%, respectively. The grade of PGMs enriched in the flotation concentrate is 420 g/t through the flotation technology.

Action of progesterone on contractile activity of isolated gastric strips in rats

AIM: To study the effect of progesterone on contractile activity of isolated gastric strips in rats.METHODS: Wistar rats were sacrificed to remove whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parellel to either the circular or the longitudial fibers, muscle strips were cut from fundus, body,antrum and pylorus. Each muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution. Then the motility of gastric strips in tissue chambers was simultaneously recorded. The preparations were subjected to 1 g load tension and washed with 5 ml Krebs solution every 20 min. After 1 h equilibration, progesterone or antagonists were added in the tissue chamber separately. The antagonists were added 3 min before using progesterone (50 μmol. L-1).RESULTS: Progesterone decreased the resting tension of fundus and body longitudinal muscle (LM) (P＜0.05). It inhibited the mean contractile amplitude of body and antrum LM and circular muscle (CM), and the motility index of pyloric CM (P＜0.05). The inhibition of progesterone on the mean contractile amplitude could be partially blocked by phentolamine in LM of the stomach body (the mean contractile amplitude of body LM decreased from -7.5±5.5to -5.2±4.5 P＜0.01), and by phentolamine or indomethacin in CM of body (The inhibition of progesterone on the mean contractile amplitude of body CM decreased from -5.6±3.0to -3.6±2.7 by phentolamine and from -5.6±3.0 to -3.5±2.5by indomethacin, P＜0.01). Hexamethonium, propranolol and L-NNA (inhibitor of NO synthetase) didn′t affect the action of progesterone (P＞0.05).CONCLUSION: The study suggested that progesterone can inhibit the contractile activity of isolated gastric strips in rats and the mechanism seems to be a direct one except that the action on gastric body is mediated through prostaglandin and adrenergic α receptor partly.

Sesamin enhances nitric oxide bioactivity in aortas of spontaneously hypertensive rats

OBJECTIVE To explore the underlying mechanisms involved in the effect of sesamin on aortic NO bioactivity in spontaneously hypertensive rat(SHR).METHODS Sesamin was orally administered for consecutive 8 weeks in SHR.Systolic blood pressure(SBP)was measured using the tail-cuff method.The aortas were isolated and in vitro vascular reactivity studies were performed.Superoxide anion production in carotid arteries was assessed by dihydroethidium fluorescence staining.The protein expression of endothelial nitric oxide synthase(eNOS),phosphorylated eNOS(P-eNOS),dihydrofolate reductase(DHFR),nicotinamide adenine dinucleotide phosphate(NADPH)oxidase subunit p47 phox and copper,zinc-superoxide dismutase(Cu/Zn-SOD)in aortas was detected by Western blotting.The dimeric form of eNOS in aortas was determined by low-temperature SDS-PAGE.Aortic level of nitrotyrosine and activities of antioxidant enzymes,namely,total SOD(T-SOD),glutathione peroxidase(GPx)and catalase were also detected.RESULTS In SHR,sesamin treatment reduced SBP,improved vascular relaxation induced by acetylcholine and enhanced aortic NO bioactivity.Sesamin treatment enhanced NO biosynthesis in SHR aortas was due to upregulated P-eNOS and suppressed eNOS uncoupling,and the latter effect might be attributed to decreased nitrotyrosine and upregulated DHFR.Sesamin also reducd the NO oxidative inactivation and decreased the superoxide anion production through downregulation of p47 phox and amelioration of eNOS uncoupling.In addition,sesamin treatment did not alter the levels of GPx and catalase activity but obviously reduced the compensatory elevated T-SOD activity and Cu/Zn-SOD protein expression.CONCLUSION Chronic treatment with sesamin could reduce hypertension and improve endothelial dysfunction through enhancement of NO bioactivity in SHRs aortas.

REGULAR EXPRESSION OF DISCOIDIN DOMAIN RECEPTOR 2 IN THE IMPROVED ADJUVANT-INDUCED ANIMAL MODEL FOR RHEUMATOID ARTHRITIS

Objective To investigate the expression of discoidin domain receptor 2 (DDR2) of fibroblast-like synovial cells in im- proved adjuvant-induced animal (AIA) model for rheumatoid arthritis (RA) and to provide evidence for DDR2’s antagonist use clinically. Methods AIA was modified by administrating 0.1 mL of complete Freund’s adjuvant (CFA, mixed with 5 mg Bacillus Calmette-Guerin vaccine/mL) into rats’ right hind paws and 0.125 mL tumor necrosis factor-α (2 U/mL) into right ankles and subpatellar fatty tissue. The expression of DDR2 in fibroblast-like synovial cells was assessed using immunohistochemistry, immunofluorescence histochemistry, and in situ hybridization methods. Levels of anti-collagen II antibody were measured using enzyme-linked immunosorbent assay. Results Given the terms mentioned above, we found a more practical rat model, apparently decreasing immunization time (average 3-5 days). DDR2 can be detected upon the 15th day of immunization; expression gradually increased with time going on, and reaching a peak 35 days after immunization before gradually decreasing. Serum anti-collagen II antibody showed similar expression patterns as DDR2, but reached peak later than DDR2, about 40 days after immunization. Conclusion Regular expression of DDR2 in animal models infers its important role in the pathological process of RA.

Studies of the Effects of Alkali Metal Oxides Promoter on the Oxidative Methylation of Toluene with Methane over KY Zeolite Catalysts

The toluene conversion, the selectivity to styrene and ethylbenzene( C8 selectivity) in the oxidative methylation of toluene with methane have been studied comparatively for the KY zeolite catalyst promoted with Li2O, Na2O, K2O, and Cs2O respectively. It was found that the effect of promoter decreased in the order: Cs2O>Na2O>Li2O>K2O.

Liguzinediol protects against apoptosis induced by doxorubicin in H9C2 cells

OBJECTIVE Liguzinediol is a derivative of the natural active ingredient ligustrazine,and we found that liguzinediol has significant positive inotropic effects,which are stronger than that of TMP.Besides,it does not lead to arrhythmia,hypotension and other side effects.This study aims to investigate the anti-apoptotic effects of liguzinediolon H9C2 cells.METHODS Apoptotic H9C2 cells induced by DOX were observed by electron microscope and FCM analysis.The protein expressions of Bax,Bcl-2,caspases 3 and NF-κB were detected by Western blotting.RESULTS Apoptotic H9C2 cells induced by DOX were observed,but without apoptotic bodies in liguzinediol group.Declined peak of H9C2 cell apoptosis was seen in liguzinediol group by FCM analysis.And downregulation of Bax,caspases 3,NF-κB and upregulation of Bcl-2 were found by Western blotting.CONCLUSION Liguzinediol protected cardiomyocytes against apoptosis through downregulation of Bax and caspases 3 and upregulation of Bcl-2.Liguzinediol can inhibited cardiomyocyte apoptosis through the NF-κB signal pathway.

Experiment Study of Retinal Ultrastructure after Intravitreal FK506

Purpose:To investigate the retinal toxicity of FK506 by intravitreal administration.Methods:Twenty-two eyes of 14 New Zealand rabbits were investigated. FK506 at concentrations of 5,25 and 50μg/eye was injected into the vitreous cavities respectively. The control eyes were received mixed solution of balanced salt and ethanol. All eyes were examined by tonometry, slit lamp and indirect ophthalmoscopy preoperatively and postoperatively at the 1st, 3rd, 7th,and 14th day respectively. In the final examination, all eyes were enucleated and processed for light and electron microscopy. Results:No evidence of toxic reaction was seen in the eyes received 25μg FK506 or less of FK506. Several eyes received 50μg FK506 and control eyes developed conjunctival congestion and slightly bloody exudates in anterior chamber which may be related to irritation of ethanol. Two of five eyes received 50μg developed transient vitreous opacities. Electron microscopically, the mitochondria of the photoreceptor cells were swelled in the eyes treated with 50μg FK506.Conclusion:It is safety with intravitreal FK506. There are no irritation and toxicity to the rabbits eyes with the intravitreal doses of 25μg FK506 or less. The doses of 50μg FK506 are proved to be toxic to the retina. Eye Science 2004;20:34-38.

Molecular Cloning of a Novel Bovine Homologue of the Drosophila Tumor Suppressor Gene,Lats

Pervious studies demonstrate that lats, also known as warts, is a tumor suppressor gene in Drosophila . Mutations of lats lead to an increase in cell number and organ size in Drosophila, indicating lats may be involved in organ size control. Furthermore, the high conservation of sequence and tumor suppression function of lats between Drosophila and human suggests that it may be also involved in organ size control of higher animals . So here we isolated the bovine homologue of Drosophila lats. Sequence analysis indicates the bovine LATS1 to be very similar to other lats proteins.

在感染真菌C．acutatum的柑桔花器中控制激素合成和调节的基因的高效表达是开花后果实脱落的诱发剂

柑桔开花后的果实脱落是由C.acutatum引起的，其特点是花瓣褐色坏死、花腐病和未成熟果实脱落。最早注意到花前果实脱落是1956年，但对该病害的描述和诱发真菌的报道是20年后。从此以后，花前果实脱落就在美国湿润热带和亚热带广泛流行，变成了许多柑桔产地的限制生产因子。

Analysis of the Expression of Fas,FasL and Bcl-2 in the Pathogenesis of Autoimmune Thyroid Disorders

To investigate the expression of apoptosis-related protein(Fas,FasL,and Bcl-2)in the pathogenesis of autoimmune thyroid disorders (ATDs),immunohistochemical staining was performed on 20 Hashimoto's thyroiditis(HT),20 Graves'disease(GD),and 20 thyroid follicular adenoma(TFA,as control).All the cases expressed Fas,mainly on the cell surface and cytoplasm.FasL was found in 17 cases of the TFA.Bcl-2 was detected in 15 cases of HT,19 of GD and 17 of TFA.In TFA,a moderate Fas expression and a minimal or no FasL expression was detected on follicular cells.In HT,the follicles adjacent to infiltrating lymphocytes showed increased levels of Fas and FasL expression.A weaker staining of Fas and FasL was exhibited on infiltrating lymphocytes than on thyrocytes.In a comparison of GD with HT,thyrocytes and lymphocytes showed similar Fas staining,but for FasL the staining was rather weaker in HT.The expression of Bcl-2 was nearly identical in GD and TFA,but much weaker on the follicular cells in vicinity of lymphocytes and on the lymphocytes located in germinal centers of HT tissues.The expression of Fas,FasL,Bcl-2 in Hashimoto's thyroiditis and Graves' disease were almost same.FasL strong expression and Bcl-2 weak expression on the follicles in HT may induce apoptosis.These results provided evidence for expression of Fas,FasL and Bcl-2 in the pathogenesis of autoimmune thyroid disease.The lymphocytes seem not to be directly engaged in the process via their own FasL,but they may provide some cytokines that,in turn,upregulate Fas and/or FasL expression to induce apoptosis.Cellular & Molecular Immunology.2004;1(3):224-228.

The Structural Characterization and Antigenicity of the S Protein of SARS-CoV

The corona-like spikes or peplomers on the surface of the virion under electronic microscope are the most striking features of coronaviruses. The S (spike) protein is the largest structural protein, with 1,255 amino acids, in the viral genome. Its structure can be divided into three regions: a long N-terminal region in the exterior, a characteristic transmembrane (TM) region, and a short C-terminus in the interior of a virion. We detected fifteen substitutions of nucleotides by comparisons with the seventeen published SARS-CoV genome sequences, eight (53.3%) of which are non-synonymous mutations leading to amino acid alternations with predicted physiochemical changes. The possible antigenic determinants of the S protein are predicted, and the result is confirmed by ELISA (enzyme-linked immunosorbent assay) with synthesized peptides. Another profound finding is that three disulfide bonds are defined at the C-terminus with the N-terminus of the E (envelope) protein, based on the typical sequence and positions, thus establishing the structural connection with these two important structural proteins, if confirmed. Phyloge-netic analysis reveals several conserved regions that might be potent drug targets.

A Genome Sequence of Novel SARS-CoV Isolates: the Genotype, GD-Ins29, Leads to a Hypothesis of Viral Transmission in South China

We report a complete genomic sequence of rare isolates (minor genotype) of the SARS-CoV from SARS patients in Guangdong, China, where the first few cases emerged. The most striking discovery from the isolate is an extra 29-nucleotide sequence located at the nucleotide positions between 27,863 and 27,864 (referred to the complete sequence of BJ01) within an overlapped region composed of BGI-PUP5 (BGI-postulated uncharacterized protein 5) and BGI-PUP6 upstream of the N (nucleocapsid) protein. The discovery of this minor genotype, GD-Ins29, suggests a significant genetic event and differentiates it from the previously reported genotype, the dominant form among all sequenced SARS-CoV isolates. A 17-nt segment of this extra sequence is identical to a segment of the same size in two human mRNA sequences that may interfere with viral genome replication and transcription in the cytosol of the infected cells. It provides a new avenue for the exploration of the virus-host interaction in viral evolution, host pathogenesis, and vaccine development.

The Structure Analysis and Antigenicity Study of the N Protein of SARS-CoV

The Coronaviridae family is characterized by a nucleocapsid that is composed of the genome RNA molecule in combination with the nucleoprotein (N protein) within a virion. The most striking physiochemical feature of the N protein of SARS-CoV is that it is a typical basic protein with a high predicted pI and high hydrophilicity, which is consistent with its function of binding to the ribophosphate backbone of the RNA molecule. The predicted high extent of phosphorylation of the N protein on multiple candidate phosphorylation sites demonstrates that it would be related to important functions, such as RNA-binding and localization to the nucleolus of host cells. Subsequent study shows that there is an SR-rich region in the N protein and this region might be involved in the protein-protein interaction. The abundant antigenic sites predicted in the N protein, as well as experimental evidence with synthesized polypeptides, indicate that the N protein is one of the major antigens of the SARS-CoV. Compared with other viral structural proteins, the low variation rate of the N protein with regards to its size suggests its importance to the survival of the virus.