A Cerasus humilis transcription factor, ChDREB2C, enhances salt tolerance in transgenic Arabidopsis.

DREB transcription factors play important roles in plant responses to various abiotic and biotic stresses. We conducted bioinformatics analysis of ChDREB2C, explored subcellular localization, transcription activation activity, and heterologous expression in Arabidopsis, and measured expression of related physiological indicators and genes under salt stress. A transcription factor of the DREB family was cloned and named ChDREB2C. ChDREB2C protein was localized in the nucleus, and its C-terminal domain exhibited transcriptional activation activity. ChDREB2C formed a homologous dimer in yeast. Arabidopsis plants overexpressing ChDREB2C were more tolerant to salt stress than WT plants, through increased scavenging capacity of ROS and accumulation of proline. Overexpression of ChDREB2C resulted in increased expression of AtSOS1, AtNHX1, AtRD29A, AtRD29B, AtKIN1, AtABA4, and AtABF2 genes. The interaction between ChABF2 (ABA response element binding factor 2) and ChDREB2C was verified using yeast two-hybrid and firefly luciferase assays. The results suggest that ChDREB2C could have a positive role in mediating the abiotic response.

Genetic diversity analysis of sweet kernel apricot in China based on SSR and ISSR markers.

Simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) markers were used to evaluate genetic diversity among 22 sweet kernel apricot accessions and 12 cultivars in China to provide information on how to improve the utilization of kernel apricot germplasms. The results showed that 10 pairs of SSR primers screened from 40 primer pairs amplified 43 allelic variants, all of which were polymorphic (100%), and 9 ISSR primers selected from 100 primers amplified 67 allelic variants with 50 polymorphic bands (74.63%). There was a relatively distant genetic relationship between the 34 samples, where their genetic similarity coefficient was between 0.62 and 0.99. The UPGMA dendrogram constructed using combined data of the two marker systems separated the genotypes into three main clusters.

Discrete roles of hepatocytes and nonparenchymal cells in uridine catabolism as a component of its homeostasis.

Previous studies indicated that uridine is essentially cleared in a single pass through a rat liver and replaced in a highly regulated manner by uridine formed presumably by de novo synthesis. We report a cellular basis for the catabolic component of this apparent paradox by dissociation of the liver with collagenase into two cell fractions, hepatocytes and a nonparenchymal cell population. Suspensions of the nonparenchymal cells rapidly cleave uridine to uracil, whereas in hepatocytes this activity was <5% of that in nonparenchymal cells. Conversely, hepatocytes cause extensive degradation of uracil to -alanine. These differences correlate with the uridine phosphorylase and dihydrouracil dehydrogenase activity in cell-free extracts of each cell type. We have documented the existence of a Na+-dependent, nitrobenzylthioinosine-insensitive transport system for uridine in the parenchymal cells (Michaelis constant 46 +/- 5 microM) that achieves a three- to fourfold concentration gradient in hepatocytes. A similar system is present in the nonparenchymal cell population. In addition, a highly specific and active Na+-dependent transport system for beta-alanine, the primary catabolic metabolite of uracil, has been demonstrated in hepatocytes.

[Studies on improving the ability of learning and memories of yangshoudan].

OBJECTIVE: To observe the effects of Yangshoudan(YSD) on the ability of learning and memories in experimental animals. METHODS: The tests of darkness-avoidance response in normal young mice and rats, aged mice, as well as in model mice with dysmnesia induced by anisodine, model rats with dysmnesia induced by scopolamine hydrobromide and with orientation disturbance induced by pentobarbital sodium. RESULTS: In normal young mice and rats, the error times in five minutes in learning and memories tests was reduced (P < 0.01-0.05) by YSD, while in dysmnesia groups the error times in five minutes also reduced (P < 0.01-0.05) and the incubation period of memories could be shortened by YSD. In orientation disturbance mice, the averages and percentages of correct response times increased by YSD. CONCLUSIONS: YSD could improve the memory ability both in normal and dysmnesia which either induced by drugs or due to age. This indicates primarily that YSD has the effects of improving the ability of learning and memories and of antidementia.

Significance of monoclonal antibody SC3A expression in gastric carcinoma and precancerous lesion.

AIM: To study the significance of monoclonal antibody SC3A expression in gastric carcinoma and precancerous lesions. METHODS: Immunohistochemical staining and mucin histochemical staining were performed on paraffin-embedded sections from gastric benign and malignant lesions from 101 patients. RESULTS: SC3A positive rate was 80.3% (57/71) in lesions of gastric carcinoma. The expression of SC3A was not related to the classification, differentiation, metastasis and or survival rates. The positive rate of SC3A in cancers secreting acid mucin (90.2%) or sulphomucin (91.3%) was higher than that in cancers without acid mucin (20.0%) or sulphomucin (60.0%) (P < 0.01). The positive rate of sulphomucin was higher in cases of intestinal metaplasia with cancer (88.9%) than that of cases of intestinal metaplasia with a benign lesion (35.3%) (P < 0.01). Additionally, the positive rate of SC3A with sulphomucin in intestinal metaplasia (60.9%) was higher than that without sulphomucin (31.3%) (P < 0.05). CONCLUSION: SC3A monoclonal antibody might be helpful in the diagnosis of gastric cancer and the discernment of histogenesis.

Tamoxifen induces Na+ -dependent uridine transport and dome formation in a human breast tumor cell line.

PURPOSE: To correlate changes in uridine transport and colony morphology with differentiation of human breast cancer cells by tamoxifen and related agents. MATERIALS AND METHODS: Cultures of MCF-7 human breast cancer were treated with estradiol or the antiestrogen derivatives tamoxifen, hydroxytamoxifen, and ICI 164, 384. Initial rates of uridine transport and equilibrium concentrations were determined and morphological characteristics of the cultures evaluated. RESULTS: Tamoxifen causes an early induction of a Na+ -dependent transport of uridine characteristic of normal epithelial cells but absent in normal MCF-7 cultures and most human neoplasms examined. The pure antiestrogen ICI 164,384 and the more potent 4-hydroxytamoxifen also induced concentrative uridine transport; estradiol could prevent the expression of this transporter. Associated with induction of transport was a dramatic increase in dome formation in the cultures, a measure of unidirectional inorganic ion transport characteristic of the differentiated state. CONCLUSIONS: The induction of a concentrative transport of uridine is a concomitant of cellular differentiation of breast tumor cells. These findings give added weight to evidence that uridine may play a regulatory role in the transition to the neoplastic state. The absence of the transporter and low intracellular uridine concentrations in the undifferentiated state may relate to 5-FU sensitivity of breast tumors. Induction of the transporter by tamoxifen and the consequent major increase in intracellular concentrations of free uridine suggests a potentially negative effect of tamoxifen on regimens containing 5-FU.

[Sharing antigenic determinant of colon carcinoma between serous and mucinous tumors of the ovary].

Expression of colon-ovarian tumor antigen (COTA) in serous and mucinous tumors of the ovary was determined immunohistochemically, using monoclonal antibody SC13A against colon carcinoma antigen as a probe. In 67 serous tumor of the ovary, the frequency of expression was 90.0% in the cystadenocarcinomas, 71.4% in the borderline cystadenomas, and only 8.0% in the cystadenomas. In 44 mucinous tumors of the ovary, the SC13A marker was expressed in 87.5% of the malignant tumors, 80.0% of the borderline tumors, and 25.8% of the benign cystadenomas. And in 20 samples of normal ovarian tissue a negative immunostaining for the SC13A was found. These findings showed that the serous and the mucinous tumors share the same antigenic determinant of colon cancer, and the percentage expression of which is significantly higher in the malignant than in the benign and the borderline tumors, as well as in the normal ovarian tissues (P < 0.005). The marker might be valuable for further studies of these tumors.

[Characteristics and reactivities of a panel of monoclonal antibodies (McAbs) recognizing human colon cancer associated antigens].

Characteristics and reactivities of 16 monoclonal antibodies (McAbs) were identified. They were prepared from mice immunized with freshly isolated colon carcinoma cells. Of these 16 McAbs, 13 belonged to IgG1, and 3 to IgM. The reactivities by immunohistochemical staining revealed 2 varieties: tumor-associated antigens and common normal tissue antigens as defined by McAbs with 737 kinds of tissues and cells from more than 12,000 samples. The antigens defined by McAbs were assayed by western immunoblotting to have a about molecular weights of 200 KD as glycoproteins unrelated to CEA. These results suggest that these McAbs may be used for further research on cancers.

[Evaluation of serum SC6 antigen using immunoradiometric assay for diagnosis of pancreatic cancer].

A solid-phase immunoradiometric sandwich assay for SC6 antigen was defined by a monoclonal antibody (SC6). The concentration of SC6 antigen in samples was determined by reference to a standard curve. The average intra- and interassay CV were 5.4% and 8.7% respectively. This antibody was found at low concentration in serum from 33 healthy individuals and the cutoff of normal upper limit of SC6 antigen was 41 U/ml. The level of serum SC6 antigen was assayed in 41 patients with pancreatic cancer, 95 with non-pancreatic carcinomas, and 48 with nonmalignant diseases. Frequency of elevated SC6 antigen level was highest in patients with gastrointestinal cancer, especially pancreatic cancer. The sensitivity and specificity were 70.7% and 84.3% for pancreatic cancer. The level in most cases of benign diseases was within upper normal limit. The results show that detection of SC6 antigen is valuable in the diagnosis of pancreatic cancer. It may be of help for detecting pancreatic cancer in its early stage.

[Immunohistochemical analysis of physicochemical properties of target antigens with anti-tumor monoclonal antibodies].

A new simplified assay for the identification of physicochemical nature of the antigen recognized by monoclonal antibodies (MAbs) against tumor using direct immunohistochemical methods of avidin-biotin peroxidase complex (ABC) is first described. The experimental results demonstrate that this method does not need to purify the target antigens or special equipment, but is as specific and sensitive as immunoblotting technique. For these reasons, this procedure is much simpler and less expensive than the methods previously published. This method may thus be useful to investigate the properties of antigens to which MAbs are directed.

Characteristics of hemopoietic stem cells determined by single spleen colony transplantation.

By using a spleen colony transfer technique and sex chromosome determinations as a cytogenetic marker, we compared the spleen colony-forming cells of bone marrow origin from three strains of mice, i.e., LACA, C57, and (LACA female X C57 male) F1. The proliferation potential of spleen colony-forming cells was found to be heterogeneous in nature. Some of the cells have the essential characteristics of hemopoietic stem cells (Ps-CFUS), i.e., the capacity for sustained proliferation and differentiation into myeloid and lymphoid lineages of cells, whereas others exhibit the capacity to form gross colonies on irradiated recipient spleen which are capable of differentiating different lineages of blood cells, but have lost the ability to reconstitute hemopoiesis in lethally irradiated recipients (Pg-CFUS). The results of studies on spleen colony-forming cells of F1 mice indicate the existence of a subpopulation of primitive precursors of spleen colony-forming cells (Pre-CFUs) which are not able to form spleen colonies on recipient spleens, but, under appropriate stimuli, may assume the properties of Ps-CFUS. Therefore the sequential process of blood cell differentiation may be described as follows: Pre-CFUS----Ps-CFUS----Pg-CFUS----different lineages of hemopoietic progenitors----different lineages of blood cells.

Comparative studies on the characteristics of proliferation and differentiation of spleen colony-forming cells.

Using a single spleen colony transplantation technique and sex chromosome typing as a natural cytogenetic marker, most spleen colony-forming cells (CFC) in adult bone marrow or fetal livers of inbred LACA or C57 mice re-established hemopoiesis in lethally irradiated mice when the spleen colonies were sampled at 13 days after transplantation. However, most of the spleen colony-forming cells in the peripheral blood of normal mice possess little potential for proliferation and are less efficient in the re-establishment of hemopoiesis in lethally irradiated mice. The CFC population is heterogeneous in the mice. From the subsequent retransplantation of colonies from colony-forming cells in the peripheral blood, the simple assessment of spleen colony-forming units (CFU-s) content, based on the number of splenic colonies, does not reliably represent the content of hemopoietic stem cells.