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At a rice-wheat rotational free-air CO2 enrichment( FACE) platform, the effect of elevated atmospheric CO2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO2 (ambient 370 microl/L + 200 microl/L). 32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effect of elevated atmospheric CO2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO2 may indicate the change of soil food web.

Background & Objective: Pre-symptomatic screening of early-stage breast cancer may greatly reduce tumor-related mortality. Some tumor markers, such as CA15-3 and CA27-29, are recommended only for monitoring therapy of advanced or relapsed breast cancer. This study was to find new biomarkers that could be used individually or in combination with an existing modality for cost-effective screening of breast cancer by proteome analysis., Methods: Protein expression differences among 128 serum samples of 64 breast cancer patients (19 of stage I, 24 of stage II, and 21 of stage III), 52 patients with benign breast diseases, and 12 healthy women were analyzed with IMAC3 and WCX2 Ciphergen ProteinChip Arrays., Results: On WCX2 chip, a panel of 5 proteins (9 116, 8 905, 8 749, 9 470, and 9 692 Da) was selected based on their collective contribution to the optimal separation between breast cancer patients and both non-cancer patients and healthy women, and expression of another 2 proteins (9 405 and 6 424 Da) was different between patients with breast cancer of stage I and stage III. On IMAC3 chip, a panel of 9 proteins (5 236, 7 823, 7 464, 5 213, 5 334, 5 064, 5 374, 7 756, and 7 623 Da) was selected based on their collective contribution to the optimal separation between breast cancer patients and both non-cancer patients and healthy women, and expression of another 3 proteins (7 922, 4 641, and 5 910 Da) was different between patients with breast cancer of stage I and stage III., Conclusion: Protein expression in breast cancer patients is different from that in both non-cancer patients and healthy women, and those proteins with different expression may be used as new biomarkers in breast cancer.

Aim: To find new serum biomarkers for liver cirrhosis (LC) in chronic carriers of hepatitis B virus (HBV)., Methods: Surface enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry was used to discover biomarkers for differentiating HBV induced LC from non-cirrhotic cohorts. A training population of 25 patients with HBV-induced LC, 20 patients with HCC, and 25 closely age-matched healthy men, was studied., Results: Two biomarkers with M(r) 7 772 and 3 933 were detected in sera of non-cirrhotic cohorts, but not in patients with HBV-induced LC. A sensitivity of 80% for all LC patients, a specificity of 81.8% for all non-cirrhotic cohorts and a positive predictive value of 75% for the study population were obtained., Conclusion: These two serum biomarkers for HBV-induced LC might be used for diagnosis and assessment of disease progression.

An epidemic of severe acute respiratory syndrome (SARS) began in Foshan municipality, Guangdong Province, China, in November 2002. We studied SARS case reports through April 30, 2003, including data from case investigations and a case series analysis of index cases. A total of 1,454 clinically confirmed cases (and 55 deaths) occurred; the epidemic peak was in the first week of February 2003. Healthcare workers accounted for 24% of cases. Clinical signs and symptoms differed between children (<18 years) and older persons (> or =65 years). Several observations support the hypothesis of a wild animal origin for SARS. Cases apparently occurred independently in at least five different municipalities; early case-patients were more likely than later patients to report living near a produce market (odds ratio undefined; lower 95% confidence interval 2.39) but not near a farm; and 9 (39%) of 23 early patients, including 6 who lived or worked in Foshan, were food handlers with probable animal contact.

Objective: To analysis the risk factors influencing nosocomial infection of severe acute respiratory syndrome (SARS) in health-care workers and to evaluate effectiveness of its control and preventive measures in 13 key hospitals caring for SARS patients., Methods: Number of SARS patients, clinical conditions of them, its attack rate in health-care workers, and characteristics of hospitals, including their environment, isolating measures, etc. were investigated at the 13 hospital in Guangzhou to analyze the risk factors influencing nosocomial infection of SARS and its attack rates in health-care workers before and after implementation of preventive measures and to evaluate their effectiveness., Results: Totally, 841 patients with SARS were treated at the 13 hospitals in Guangzhou and 285 health-care workers caring for them infected nosocomially. Attack rate in health-care workers was higher at general hospitals, hospital accepting more cases in critical conditions and hospitals with poor precautious measures, and lower in hospitals with isolated wards or areas, or department of infection, specially caring for SARS patients, and those with effective intervention measures to prevent secondary infection., Conclusion: Nosocomial infection of SARS in health-care workers was affected by clinical condition of SARS patients, characteristics and environment of hospitals and their personal protective measures adopted.

Background & Objective: Previous studies have indicated that increased expression of TGFalpha and cyclin E are correlated with the oncogenesis and progress of cancer; however, their expression patterns in gastric precancerous lesions have been not clear yet. In addition, the association between expression of TGFalpha and cyclin E has not been reported. This study was designed to investigate the expression of TGFalpha and cyclin E in chronic superficial gastritis (CSG), gastric precancerous lesions, and gastric carcinoma (GCA), and analyze the association of TGFalpha and cyclin E expression, and the relationship between their expression and different development stages of oncogenesis of GCA., Methods: The expression of TGFalpha and cyclin E in CSG, intestinal metaphases (IM), atypical hyperplasia (AH), and GCA were examined using immunohistochemical staining. The association of TGFalpha and cyclin E expression was also statistically analyzed., Results: The expression rates of TGFalpha and cyclin E were 15.1%, 53.6%, 51.7%, 61.7%, and 7.5%, 28.6%, 37.9%, 42.6% in tissue samples of CSG, IM, AH and GCA, respectively. The positive expression rates of TGFalpha and cyclin E were higher in IM, AH, GCA than in CSG; the difference was significant (each P< 0.05). In addition, the positive expression rates of TGFalpha and cyclin E were higher in low differential adenocarcinoma (TGFalpha 81.0%, cyclin E 57.1%) than in mediate to high differential one (TGFalpha 41.7%, cyclin E 16.7%) (P< 0.05,for both TGFalpha and cyclin E). It is also revealed that the expression of TGFalpha and cyclin E were closely associated (P< 0.001 for the tissue of gastric chronic inflammation, and P=0.005 for gastric carcinoma, respectively)., Conclusion: In the tissues of CSG, IM, AH, and GCA, the expression rates of TGFalpha and cyclin E are increased gradually with the severity of the pathological lesions and the malignancy of GCA. In addition, the expression of TGFalpha and cyclin E were obviously associated.

Objective: To provide a basis for development and preparation of the new anti-tumor agents from Cortex A-canthopanacis senticosus (CAS), through isolating the active substances from CAS and studying the anti-tumor effect of CAS extracts in vivo and in vitro., Methods: The effects of CAS extracts and its isolated ingredients on tumor cell proliferation in vitro was determined by 3H-TdR incorporation; the anti-tumor component of CAS was isolated and purified by chromatography; the tumor bearing mice model was established by injecting tumor cell subcutaneously, and the model was used to observe the anti-tumor effect of CAS extract administered through gastrogavage., Results: CAS extract showed obvious inhibition on tumor cell proliferation originated from multiple tissues (P < 0.01) and displayed a better dose-effect relationship. After orally taken CAS extract, the general condition of mice in the experimental group were better than that in the untreated control group, revealing a slower growth and significantly prolonged survival period (P < 0.01). A protein component, having inhibitory effect on tumor cell proliferation and the molecular weight was 64 kda, it was isolated by the thin layer gel chromatography., Conclusion: CAS has not only the in vitro inhibitory effect on cell proliferation of multiple kinds of tumor, but also a good anti-tumor effect in vivo. The anti-tumor activity of CAS is correlated with a protein component with the molecular weight of 64 kda. Further isolation, purification, study on mechanism will provide scientific evidence for clinical application and development of CAS in anti-tumor effect.

Objective: To evaluate the effectiveness of personal protective measures of health care workers (HCWs) against severe acute respiratory syndrome (SARS)., Methods: A case-control study from ten hospitals in Guangdong, with 180 non-infected and 77 infected staff members that accessed the isolation unit every day, and participated in direct first aid for severe SARS patients. All participants were surveyed about how they were using personal protective equipment (PPE), protective drugs and hygiene habits when caring for patients with SARS. Statistical analysis was done with either chi(2) or Fisher's exact test for univariate analysis, whereas we used forward stepwise selection (Waldesian) for logistic regression., Results: Univariate analysis showed that mask, gown, gloves, goggles, footwear, "hand-washing and disinfecting", gargle, "membrane protection", "taking shower and changing clothing after work", "avoid from eating and drinking in ward", oseltamivir phospha tall had protective effects (P < 0.05), but stepwise logistic regression showed significant differences for mask (OR = 0.78, 95% CI: 0.60 - 0.99), goggles (OR = 0.20, 95% CI: 0.10 - 0.41) and footwear (OR = 0.58, 95% CI: 0.39 - 0.86). Analysis for linear trend in proportions showed that dose response relationship existed in mask, gown, gloves, goggles, footwear, gargle, "membrane protection" and "taking shower and changing dree after work" (P < 0.01). The attack rate of HCWs who were rescuing severe SARS patients without any PPE was 61.5% (16/26). It seemed that the more the protective measures were used, the higher the protective effect was (P < 0.001), and could reach 100% if mask, gown, gloves, goggles, footwear, "hand-washing and disinfecting" were all used at the same time., Conclusions: Nosocomial infection of SARS can be prevented effectively by precautions against droplets and personal contact. HCWs must take strict protection according to the guidance of WHO or Chinese MOH and pay attention to personal hygiene.

Background & Objective: We cloned NP9 gene (GenBank, BF718797) in a previous study which was down-regulated in nasopharyngeal carcinoma (NPC). To clarify the function of NP9 gene, we cloned the coding sequence (CDS) of NP9 gene and investigated the influence of NP9 on cyclin D1 expression., Methods: A full-length cDNA sequence was obtained by Blast NP9 EST, then the complete CDS was cloned into an eukaryotic expressing vector pRc/CMV2. The plasmid was transfected into CNE1 cells (NPC cells) with lipofectamine and positive cell clones which stably expressed NP9 CDS were established by G418 screening. The luciferase report plasmid with cyclin D1 promoter or NF-kappaB-Luc report plasmid was transfected into positive clones and the luciferase activity was detected. At last, the NP9 CDS was subcloned into pEGFP-C1 and cellular localization of NP9 protein was observed through transfecting pEGFP-C1-NP9 into CNE1 cells., Results: The fusion GFP was located in cell nuclei. The positive cell clones screened by G418 expressed NP9 CDS at different levels. Compared with control, the luciferase activities in NP9 positive clones were decreased 46% and 63% after 48 hours of transfecting the luciferase report plasmid with cyclin D1 promoter or NF-kappaB-Luc plasmid., Conclusion: NP9 protein is a nuclear protein. NP9 gene can down-regulate the transcription activity of cyclin D1 and NF-kappaB.

Objective: To explore epidemiological features and risk factors of severe acute respiratory syndrome (SARS) in Guangdong Province of China, so as to work out effective strategies for its better control., Methods: A total of 1 511 clinically confirmed SARS cases in Guangdong Province of China from November 16, 2002 to Jun 15, 2003 were retrospectively analyzed., Results: The first SARS case was identified in Foshan municipality on November 16, 2002, followed by 1 511 clinically confirmed cases (including 58 deaths) up to May 15, 2003. Of all cases, health care workers and community family cluster cases accounted for 19.38% and 12.04%. 65.86% SARS patients aged 20 - 49 years, and increased incidence was positively related to their ages. 95.97% cases lived in the following five cities around Pearl Delta Area: Foshan, Guangzhou, Shenzhen, Zhongshan, and Jiangmen. Eleven early reported cases in the communities took animal-related positions. Face-to-face contacts with infected droplets were the main transmission route. An epidemic peak occurred during January 28 to February 26, and those cases accounted for 50.69% of total. Incidence, mortality, and case fatality of SARS were 1.77/100,000, 0.07/100,000, and 3.84% respectively. The mean incubation period was 4.5 days., Conclusion: The most effective way to control SARS is to break the chain of transmission from infected to healthy persons-early identification, prompt and effective isolation, and vigorous close contact tracing. Hospital infections among health care workers is critical. Several observations support the hypothesis of an animal origin for the disease.

Objective: To analyze the epidemiological features of the index cases of severe acute respiratory syndrome (SARS) occurred in different cities in Guangdong province and to trace for the source of infection., Methods: Standardized individual case inventory was adopted to conduct investigation on index cases and on persons who had close contact with index cases in Guangdong province. Data on the epidemiological characteristics, secondary cases and the links among index cases were analyzed., Results: Between November 16, 2002 and April 16, 2003, there had been 13 index cases of SARS including 3 cadres, 3 farmers, 2 retirees, 2 workers and 1 shop attendant, reported from 13 cities in Guangdong province. Between November 2002 and January 2003, there had been 7 cities reported to have identified index cases of SARS with 6 of them being infected in their own cities and 1 imported from Guangzhou city. All of the cases had no close contacts to similar patients but 6 of them later caused 2nd or even 3rd generation cases of SARS. Most cases hit young people (7/13) with a sex ratio of 1:0.6. The fatality rate of index cases was high (4/13)., Conclusion: No evidence showed that there was direct transmission among the index cases. Data regarding the geographical origin of those index cases led to the assumption that the infection had started in six cities of Pearl river delta region and the Hong Kong Special Administrative Region.

Objectives: To understand the epidemiological characteristics of severe acute respiratory syndrome (SARS) outbreaks in some areas of Guangdong province and to provide scientific basis for prevention and control measures against it., Methods: Standardized questionnaire was used on individual cases. Data on the epidemiological characteristics as time, place, persons and aggregation status of SARS cases, development of the epidemics, were analyzed with software EPI 6.0., Results: The incidence of SARS in Guangdong province was 1.72/100,000 with case fatality rate as 3.64%. Most cases of SARS occurred between the last ten days of January and the first ten days of February with the peak (61.88% of the patients) occurred in the first ten days of February. As to the distribution of place, Pearl river delta region-economically developed with great number of mobile population-was heavily affected areas (account for 96.66% of the total patients). The majority of patients were young adults and medical staff seemed to be the most affected subgroup (account for 24.9% of the patients in total). Family and hospital aggregation of patients comprised the another two important characteristics of SARS (account for 37.1% of the total patients)., Conclusion: Current knowledge on SARS suggested that it was an air-borne infectious disease with human beings served as the source of infection. The incubation period of the disease was from 1 to 12 days with a median of 4 days. Respiratory secretions and close contact contributed to person-to-person transmission. Most cases were distributed in Pearl river delta region, an area famous for its economic development and heavy flow of mobile population.

Protein kinase C (PKC) regulation of l-ascorbic acid transport mediated by the Na+/ascorbic acid transporters, hSVCT1 and hSVCT2, expressed in COS-1 cells was studied using recombinant carboxyl-terminal V5 epitope-tagged forms of the transporters. The PKC activator phorbol 12-myristate 13-acetate (PMA) caused a time-dependent and concentration-dependent decrease (40-60%) in ascorbic acid transport activity. Effects of PMA were not observed with the inactive phorbol ester 4 alpha-phorbol and were reversed by treatment of the cells with the PKC-specific inhibitor Ro-31-8220. Kinetically, the reduction in hSVCT1 and hSVCT2 activity arose from a decrease in maximal velocity with no change in the apparent affinity. Western blot and confocal microscopy analyses indicated that the total pool of hSVCT1 or hSVCT2 proteins expressed in the transfected COS-1 cells remained unaffected by PMA treatment. For hSVCT1 the decrease in L-ascorbic acid correlated with a redistribution of the transporter from the cell surface to intracellular membranes. However, for hSVCT2 there was no apparent change in transporter distribution, suggesting that the PKC-dependent modulation of L-ascorbic acid transport mediated by hSVCT2 was the result of reduced catalytic transport efficiency.

Vitamin C is essential for many enzymatic reactions and also acts as a free radical scavenger. Specific non-overlapping transport proteins mediate the transport of the oxidized form of vitamin C, dehydroascorbic acid, and the reduced form, L-ascorbic acid, across biological membranes. Dehydroascorbic acid uptake is via the facilitated-diffusion glucose transporters, GLUT 1, 3 and 4, but under physiological conditions these transporters are unlikely to play a major role in the uptake of vitamin C due to the high concentrations of glucose that will effectively block influx. L-ascorbic acid enters cells via Na+-dependent systems, and two isoforms of these transporters (SVCT1 and SVCT2) have recently been cloned from humans and rats. Transport by both isoforms is stereospecific, with a pH optimum of approximately 7.5 and a Na+:ascorbic acid stoichiometry of 2:1. SVCT2 may exhibit a higher affinity for ascorbic acid than SVCT1 but with a lower maximum velocity. SVCT1 and SVCT2 are predicted to have 12 transmembrane domains, but they share no structural homology with other Na+ co-transporters. Potential sites for phosphorylation by protein kinase C exist on the cytoplasmic surface of both proteins, with an additional protein kinase A site in SVCT1. The two isoforms also differ in their tissue distribution: SVCT1 is present in epithelial tissues, whereas SVCT2 is present in most tissues with the exception of lung and skeletal muscle.

The ProP protein of Escherichia coli is an osmoregulatory H+-compatible solute cotransporter. ProP is activated by an osmotic upshift in both whole cells and membrane vesicles. We are using biochemical and biophysical techniques to explore the osmosensory and catalytic mechanisms of ProP. We now report the purification and reconstitution of the active transporter. Protein purification was facilitated by the addition of six histidine (His) codons to the 3' end of proP. The recombinant gene was overexpressed from the E. coli galP promoter, and ProP-(His)6 was shown to be functionally equivalent to wild-type ProP by enzymatic assay of whole cells. ProP-(His)6, purified by Ni2+ (NTA) affinity chromatography, cross-reacted with antibodies raised against the ProP protein. ProP-(His)6 was reconstituted into Triton X-100 destabilized liposomes prepared with E. coli phospholipid. The reconstituted transporter mediated proline accumulation only if (1) a membrane potential was generated by valinomycin-mediated K+ efflux and (2) the proteoliposomes were subjected to an osmotic upshift (0.6 M sucrose). Activity was also stimulated by DeltapH. Pure ProP acts, in the proteoliposome environment, as sensor, transducer, and respondent to a hyperosmotic shift. It is the first such osmosensor to be isolated.

The lactose transport protein (LacS) of Streptococcus thermophilus was amplified to levels as high as 8 and 30% of total membrane protein in Escherichia coli and S. thermophilus, respectively. In both organisms the protein was functional and the expression levels were highest with the streptococcal lacS promoter. Also a LacS deletion mutant, lacking the carboxyl-terminal regulatory domain, could be amplified to levels >20% of membrane protein. Membranes from S. thermophilus proved to be superior in terms of efficient solubilization and ease and extent of purification of LacS; >95% of LacS was solubilized with relatively low concentrations of Triton X-100, n-octyl-beta-D-glucoside, n-dodecyl-beta-D-maltoside, or C12E8. The LacS protein carrying a poly-histidine tag was purified in large quantities (approximately 5 mg/liter of culture) and with a purity >98% in a two-step process involving nickel chelate affinity and anion exchange chromatography. The membrane reconstitution of LacS was studied systematically by stepwise solubilization of preformed liposomes, prepared from E. coli phospholipid and phosphatidylcholine, and protein incorporation at the different stages of liposome solubilization. The detergents were removed by adsorption onto polystyrene beads and H+-lactose symport and lactose counterflow were measured. Highest transport activities were obtained when Triton X-100 was used throughout the solubilization/purification procedure, whereas activity was lost irreversibly with n-octyl-beta-D-glucoside. For reconstitutions mediated by n-dodecyl-beta-D-maltoside, C12E8, and to a lesser extent Triton X-100, the highest transport activities were obtained when the liposomes were titrated with low amounts of detergent (onset of liposome solubilization). Importantly, under these conditions proteoliposomes were obtained in which LacS was reconstituted in an inside-out orientation, as suggested by the outside labeling of a single cysteine mutant with a membrane impermeable biotin-maleimide. The results are consistent with a mechanism of reconstitution in which the hydrophilic regions of LacS prevent a random insertion of the protein into the membrane. Consistent with the in vivo lactose/galactose exchange catalyzed by the LacS protein, the maximal rate of lactose counterflow was almost 2 orders of magnitude higher than that of H+-lactose symport.

A new family of homologous membrane proteins that transport galactosides-pentoses-hexuronides (GPH) is described. By analysing the aligned amino acid sequences of the GPH family, and by exploiting their different specificities for cations and sugars, we have designed mutations that yield novel insights into the nature of ligand binding sites in membrane proteins. Mutants have been isolated/constructed in the melibiose transport proteins of Escherichia coli, Klebsiella pneumoniae and Salmonella typhimurium, and the lactose transport protein of Streptococcus thermophilus which facilitate uncoupled transport or have an altered cation and/or substrate specificity. Most of the mutations map in the amino-terminal region, in or near amphipathic alpha-helices II and IV, or in interhelix-loop 10-11 of the transport proteins. On the basis of the kinetic properties of these mutants, and the primary and secondary structure analyses presented here, we speculate on the cation binding pocket of this family of transporters. The regulation of the transporters through interaction with, or phosphorylation by, components of the phosphoenolpyruvate:sugar phosphotransferase system is also discussed.