Several reviews have analyzed the factors that affect the change in soil organic C (SOC) when forest is converted to agricultural land; however, the effects of forest type and cultivation stage on these changes have generally been overlooked. We collated observations from 453 paired or chronosequential sites where forests have been converted to agricultural land and then assessed the effects of forest type, cultivation stage, climate factors, and soil properties on the change in the SOC stock and the SOC turnover rate constant (k). The percent decrease in SOC stocks and the turnover rate constants both varied significantly according to forest type and cultivation stage. The largest decrease in SOC stocks was observed in temperate regions (52% decrease), followed by tropical regions (41% decrease) and boreal regions (31% decrease). Climate and soil factors affected the decrease in SOC stocks. The SOC turnover rate constant after the conversion of forests to agricultural land increased with the mean annual precipitation and temperature. To our knowledge, this is the first time that original forest type was considered when evaluating changes in SOC after being converted to agricultural land. The differences between forest types should be considered when calculating global changes in SOC stocks.

The Chinese genebank contains 23,587 soybean landraces collected from 29 provinces. In this study, a representative collection of 1,863 landraces were assessed for genetic diversity and genetic diVerentiation in order to provide useful information for eVective management and utilization. A total of 1,160 SSR alleles at 59 SSR loci were detected including 97 unique and 485 low-frequency alleles, which indicated great richness and uniqueness of genetic variation in this core collection. Seven clusters were inferred by STRUCTURE analysis, which is in good agreement with a neighbor-joining tree. The cluster subdivision was also supported by highly signiWcant pairwise F st values and was generally in accordance with diVerences in planting area and sowing season. The cluster HSuM, which contains accessions collected from the region between 32.0 and 40.5°N, 105.4 and 122.2°E along the central and downstream parts of the Yellow River, was the most genetically diverse of the seven clusters. This provides the Wrst molecular evidence for the hypotheses that the origin of cultivated soybean is the Yellow River region. A high proportion (95.1%) of pairs of alleles from diVerent loci was in LD in the complete dataset. This was mostly due to overall population structure, since the number of locus pairs in LD was reduced sharply within each of the clusters compared to the complete dataset. This shows that population structure needs to be accounted for in association studies conducted within this collection. The low value of LD within the clusters can be seen as evidence that much of the recombination events in the past have been maintained in soybean, Wxed in homozygous self-fertilizing landraces.

A novel coronavirus, the severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV), was identified as the causative agent of SARS. The profile of specific antibodies to individual proteins of the virus is critical to the development of vaccine and diagnostic tools. In this study, 13 recombinant proteins associated with four structural proteins (S, E, M and N) and five putative uncharacterized proteins (3a, 3b, 6, 7a and 9b) of the SARS-CoV were prepared and used for screening and monitoring their specific IgG antibodies in SARS patient sera by protein microarray. Antibodies to proteins S, 3a, N and 9b were detected in the sera from convalescent-phase SARS patients, whereas those to proteins E, M, 3b, 6 and 7a were undetected. In the detectable specific antibodies, anti-S and anti-N were dominant and could persist in the sera of SARS patients until week 30. Among the rabbit antisera to recombinant proteins S3, N, 3a and 9b, only anti-S3 serum showed significant neutralizing activity to the SARS-CoV infection in Vero E6 cells. The results suggest (1) that anti-S and anti-N antibodies are diagnostic markers and in particular that S3 is immunogenic and therefore is a good candidate as a subunit vaccine antigen; and (2) that, from a virus structure viewpoint, the presence in some human sera of antibodies reacting with two recombinant polypeptides, 3a and 9b, supports the hypothesis that they are synthesized during the virus cycle.

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Recombinant severe acute respiratory syndrome (SARS) coronavirus nucleocapsid protein was employed to establish an antigen-capturing enzyme-linked immunosorbent assay (ELISA). Antinucleocapsid protein antibodies could be detected in 68.4% of probable SARS patients 6 to 10 days after illness and in 89.6% of the patients 11 to 61 days after illness. No false-positive results were observed in 20 non-SARS fever patients, 24 non-SARS respiratory illness patients, and 20 health care workers. Among 940 other non-SARS clinical serum samples, only 1 was found to be weakly positive. This method provides a new, sensitive, and specific approach for SARS diagnosis.An accurate, rapid, and cost-effective laboratory etiologic method is of great importance for the diagnosis of severe acute respiratory syndrome (SARS). The isolation of the virus (4) led to the development of some specific diagnostic techniques, including indirect fluorescent-antibody detection, indirect enzyme-linked immunosorbent assay (ELISA) using virus lysates as antigen, and reverse transcription PCR for the detection of the SARS coronavirus (SARS CoV) genome (5). However, as observed in the clinical practices of China and shown in this paper, indirect ELISA gave about 2% false-positive results among healthy people; SARS-CoV infection could be confirmed only if seroconversion from negative to positive status was observed.Antigen-capturing ELISA is a superior method to indirect immunoassay because of its high specificity and sensitivity. The basis of the assay is that antibodies are at least bivalent, i.e., one valence is used in attaching the antibody to the immobilized antigen, leaving the other(s) free to bind to the labeled antigen. Both capture and detection of the target antibody depend on its specificity toward the antigen, so if the antigen is correctly chosen and purified, the assay can be made very specific. And principally, all types of antibodies (immunoglobulin G [IgG], IgM, IgA, etc.) could be detected (1). It has been demonstrated previously that, at least in early responses, the antibodies to the nucleocapsid protein (N protein) predominate as assayed by Western blotting (3). Therefore, the N protein was chosen to be produced as a recombinant protein for establishing an antigen-capturing ELISA for SARS diagnosis.The SARS CoV N gene was obtained by reverse transcription PCR amplification from blood samples of a SARS patient in Beijing by using the following primer pair: 5Ј-CGCATATG TCTGATAATGGACCCCA-3Ј and 5Ј-CGGATCCTTATGC CTGAGTTGAATCAGCA-3Ј. The DNA fragment was then cloned into a T7 promoter-based prokaryotic expression vector, pET22b (Novagen). The resulting recombinant plasmid (pMG-N) was subjected to DNA sequencing and showed 100% identity with the N gene reported in the SARS CoV Toronto strain (GenBank accession number NC_004718). pMG-N was then transformed into Escherichia coli BL21a (DE3) and induced with 0.5 mmol of isopropyl-␤-D-thiogalactopyranoside (IPTG) (Sigma, St. Louis, Mo.) per liter for overexpression. The recombinant N prote...

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Profiles of antibodies to the nucleocapsid protein of the severe acute respiratory syndrome (SARS)-associated coronavirus in 445 probable SARS patients and 3,749 healthy people or non-SARS patients were analyzed by antigen-capturing enzyme-linked immunosorbent assay. Antinucleocapsid antibodies were elucidated in 17.5% of the probable SARS patients 1 to 7 days after the onset of symptoms and in 80% of the patients 8 to 14 days after the onset. About 90% of the probable SARS patients were positive 15 or more days after illness. Antibody titers increased up to 70 days, and high antibody titers were maintained at least for another 3 months. Of the healthy people and non-SARS patients, only seven (0.187%) were weakly positive.The novel severe acute respiratory syndrome (SARS)-associated coronavirus (CoV) has been identified as the etiologic agent of SARS (1,3,5). It has been demonstrated that, at least in early responses, the antibodies to the nucleocapsid protein (N protein) predominate, as assayed by Western blotting and proteomic analysis. To understand the humoral immunity to the N protein of SARS CoV and the possibility of using the N protein in SARS diagnosis, antibodies to the N protein from 445 patients who probably had SARS, as diagnosed on the basis of World Health Organization criteria, from four hospitals were analyzed by an antigen-capturing enzyme-linked immunosorbent assay in which recombinant SARS N protein was used as the antigen (6). The method is briefly described as follows. The N-encoding gene of SARS CoV was cloned into T7 promoter-based prokaryotic expression vector pET22b (Novagen), and the resulting recombinant plasmid (pMG-N) was then transformed into Escherichia coli BL21a(DE3). The recombinant N protein was expressed in E. coli by induction with isopropyl-␤-D-thiogalactopyranoside (IPTG; Sigma, St. Louis, Mo.) at 0.5 mmol/liter and purified by S-Sepharose Fast Flow ion-exchange chromatography, followed by gel filtration with Superdex 200 (Amersham Pharmacia) to a purity of Ͼ97% as determined by laser densitometry of a silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel. The purified N protein was diluted to 1 g/ml with 50 mM carbonate buffer (pH 9.6) and used to coat the wells of 96-well microplates at 4°C overnight, followed by blocking with 5% fetal bovine serum for 4 h at room temperature. In addition, N protein was conjugated to horseradish peroxidase (Sigma). An antigen-capturing enzyme-linked immunosorbent assay was established for the detection of anti-N protein antibody present in sera. A 100-l volume of serum was added to the well coated with recombinant N protein, and the plate was incubated at 37°C for 30 min and then washed five times with phosphatebuffered saline containing 0.05% Tween 20. A 10-l volume of labeled antigen was added, and the plate was incubated for another 30 min and washed as already described, and then 100 l of TMB substrate solution (0.1 mg of tetramethylbenzidine hydrochloride/ml, 0.01% H 2 O 2 in 0.1 M acetate buffer, pH 5.8) was ...

The translationally controlled tumor protein (TCTP) can be secreted independently of the endoplasmic reticulum/Golgi pathway and has extrinsic activities when it is characterized as the histamine releasing factor (HRF). Despite its important role in allergies and inflammation, little is known about how extracellular TCTP affects cancer progression. In this study, we found that TCTP was overexpressed in the interstitial tissue of colorectal cancer (CRC) and its expression correlated with poor survival, high pathological grades and metastatic TNM stage in CRC patients. TCTP expression was greater in metastatic liver tissue than in primary tumors and was increased in highly invasive CRC cells. We demonstrated that the expression of TCTP was regulated by HIF-1α and its release was increased in response to low serum and hypoxic stress. Recombinant human TCTP (rhTCTP) promoted the migration and invasiveness of CRC cells in vitro and contributed to distant liver metastasis in vivo. Furthermore, rhTCTP activated Cdc42, phosphorylated JNK (p-JNK), increasing the translocation of p-JNK from the cytoplasm to the nucleus, as well as the secretion of MMP9. In addition, the expression of TCTP positively correlated with that of Cdc42 and p-JNK in clinical CRC samples. The silencing of Cdc42, JNK and MMP9 significantly inhibited the Matrigel invasion of rhTCTP-enhanced CRC cells. Collectively, these results identify a new role for extracellular TCTP as a promoter of CRC progression and liver metastases via Cdc42/JNK/MMP9 activation.