Clinical characteristics and prognostic analysis of postoperative recurrence or metastasis of low-risk gastrointestinal stromal tumors.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the digestive tract. This study aimed to investigate the clinical characteristics and prognosis of postoperative recurrence or metastasis in patients with low-risk stromal tumors, in order to take individualized postoperative management and treatment for patients with low-risk GISTs with relatively high recurrence. METHODS: We retrospectively analyzed the clinicopathological and follow-up data of patients with GISTs who underwent surgical resection in Nanjing Drum Tower Hospital from March 2010 to December 2021. A total of 282 patients with low-risk GISTs were included, none of whom were treated with imatinib. Univariate and multivariate Cox analysis and survival curves were used to explore the relationship between clinical features and recurrence or metastasis in patients with low-risk GISTs. RESULTS: Of the 282 patients with low-risk GISTs who met inclusion criteria, 14 (4.96%) had recurrence or metastasis. There was a correlation between tumor size, primary site, resection type, Ki67 index, neutrophil lymphocyte ratio (NLR) and CD34 expression and postoperative recurrence or metastasis of GISTs (P < 0.05). Subsequently, multifactorial analysis showed that tumor primary site, tumor size, and Ki67 index were independent risk factors affecting postoperative recurrent or metastasis in patients with low-risk GISTs (P < 0.05). Ultimately, According to Kaplan-Meier analysis, non-gastric primary tumors, larger tumors, and high Ki67 index were significantly associated with poor progression-free survival ( PFS ). CONCLUSIONS: Tumor location, tumor size and Ki-67 were independent risk factors for postoperative recurrence and metastasis in patients with low-risk GISTs. Based on the 2008 modified NIH recurrence risk grading system, combined with the above three factors, it can be used to evaluate the prognosis of patients with low-risk GISTs and provide personalized postoperative review and follow-up management recommendations.

Role of interleukin 6 and its soluble receptor on the diffusion barrier dysfunction of alveolar tissue.

During respiratory infection, barrier dysfunction in alveolar tissue can result from "cytokine storm" caused by overly reactive immune response. Particularly, interleukin 6 (IL-6) is implicated as a key biomarker of cytokine storm responsible for and further progression to pulmonary edema. In this study, alveolar-like tissue was reconstructed in a microfluidic device with: (1) human microvascular lung endothelial cells (HULEC-5a) cultured under flow-induced shear stress and (2) human epithelial cells (Calu-3) cultured at air-liquid interface. The effects of IL-6 and the soluble form of its receptor (sIL-6R) on the permeability, electrical resistance, and morphology of the endothelial and epithelial layers were evaluated. The diffusion barrier properties of both the endothelial and epithelial layers were significantly degraded only when IL-6 treatment was combined with sIL-6R. As suggested by recent review and clinical studies, our results provide unequivocal evidence that the barrier dysfunction occurs through trans-signaling in which IL-6 and sIL-6R form a complex and then bind to the surface of endothelial and epithelial cells, but not by classical signaling in which IL-6 binds to membrane-expressed IL-6 receptor. This finding suggests that the role of both IL-6 and sIL-6R should be considered as important biomarkers in developing strategies for treating cytokine storm.

Comparison of clinical outcomes and prognosis between surgery and endoscopic submucosal dissection in patients with synchronous multifocal early gastric cancer.

BACKGROUND: Synchronous multiple early gastric cancer (SMEGC) refers to the simultaneous occurrence of two or more malignant cancer lesions in the stomach. For patients with multiple early gastric carcinomas, the choice of appropriate treatment remains controversial. This study is dedicated to comparing the clinical outcomes and prognosis of patients with SMEGC who underwent endoscopic submucosal dissection (ESD) or gastrectomy. METHODS: A total of 180 patients with more than one malignant cancer lesion in the stomach who had received gastrectomy or ESD between 2012 and 2021 were retrospectively evaluated to determine their clinical outcomes and prognosis. Univariate and multivariate logistic regression were utilized to identify risk factors for tumor recurrence. RESULTS: Over the 57.5 months median follow-up period for the 140 enrolled cases, tumor recurrence occurred in 8 (12%) in the ESD group but only 1 (1%) in the surgery group. Relapse-free survival (RFS) was higher in the surgery group (p = 0.023) in all cases; however, there was no significant difference in Overall survival (OS, p = 0.772). Complications were significantly higher in the surgery group than in the ESD group, but fewer in the radical distal gastrectomy group. Multivariate regression analysis revealed that ESD(p = 0.034), the main lesion size > 2 cm(p = 0.019), and undifferentiated tumor(p = 0.022) were independent risk factors for tumor recurrence. CONCLUSIONS: For the treatment of simultaneous multifocal early gastric cancer, ESD has a good short-term effect and higher quality of life. However, ESD has a higher risk of recurrence than surgery. And we found that the partial gastrectomy appears to be considered as adequate treatment for some SMEGC patients.

Controlling Nutritional Status (CONUT) score as a prognostic marker for gastrointestinal stromal tumours.

BACKGROUND: The Controlling Nutritional Status (CONUT) score, regarded as the effective indicator of patient nutrition, has been demonstrated to be related to prognosis of numerous tumours. Nevertheless, the significance of CONUT for gastrointestinal stromal tumour (GIST) remains unclear. This study intended to clarify the association between CONUT and the prognosis of GISTs. METHODS: Three hundred and fifty-five patients with GISTs undergoing surgical resection at our center were retrospectively assessed. Receiver operating characteristic curve analysis was used to help determine the cut-off value of CONUT score. Relapse-free survival (RFS) and overall survival (OS) were assessed by Kaplan-Meier curve analysis. Prognostic factors for RFS and OS were examined by Cox proportional hazards models. RESULTS: A total of 355 patients were enrolled in this study. Areas under the curve (AUC) were 0.638 for CONUT score, and the cut-off value of CONUT was shown to be three. Kaplan-Meier curve analysis showed that high CONUT score was linked to poorer RFS and OS. Univariate and multivariate analyses ultimately revealed that CONUT was a risk factor for RFS and OS, independent of demographics and clinicopathological tumour characteristics. CONCLUSIONS: CONUT score was an effective and novel predictor for prognosis of GIST patients treated with surgery, indicating its potential as a prognostic marker in the overall management.

Prognostic analysis of 2-5 cm diameter gastric stromal tumors with exogenous or endogenous growth.

BACKGROUND: There has been limited research on the prognosis differences in patients with gastric stromal tumor invasion of the plasma membrane surface. This study intended to investigate whether there is a difference in prognosis in patients with endogenous or exogenous 2-5 cm diameter GISTs. METHODS: We retrospectively analyzed the clinicopathological and follow-up data of gastric stromal tumor patients, all of whom underwent surgical resection for primary GIST at Nanjing Drum Tower Hospital from December 2010 to February 2022. We classified patients based on tumor growth patterns and then investigated the association between tumor growth patterns and clinical outcomes. Progression-free survival (PFS) and overall survival (OS) were calculated by the Kaplan‒Meier method. RESULTS: A total of 496 gastric stromal tumor patients were enrolled in this study, among which 276 patients had tumors of 2-5 cm in diameter. Of these 276 patients, 193 had exogenous tumors, and 83 had endogenous tumors. Tumor growth patterns were significantly related to age, rupture status, resection style, tumor site, tumor size, and intraoperative bleeding. According to Kaplan‒Meier curve analysis, the tumor growth pattern among patients with 2-5 cm diameter tumors was significantly correlated with worse progression-free survival (PFS). Ultimately, multivariate analyses identified the Ki-67 index (P = 0.008), surgical history (P = 0.031), and resection style (P = 0.045) as independent prognostic markers for PFS. CONCLUSIONS: Although gastric stromal tumors with a diameter of 2-5 cm are classified as low risk, the prognosis is lower for exogenous tumors than for endogenous tumors, and exogenous gastric stromal tumors have a risk of recurrence. Consequently, clinicians should be vigilant regarding the prognosis of patients with this type of tumor.

The ubiquitin E3 ligase TRIM10 promotes STING aggregation and activation in the Golgi apparatus.

STING is an endoplasmic reticulum-resident protein regulating innate immunity. After binding with cyclic guanosine monophosphate-AMP (cGAMP), STING translocates from the endoplasmic reticulum (ER) to the Golgi apparatus to stimulate TBK1 and IRF3 activation, leading to expression of type I interferon. However, the exact mechanism concerning STING activation remains largely enigmatic. Here, we identify tripartite motif 10 (TRIM10) as a positive regulator of STING signaling. TRIM10-deficient macrophages exhibit reduced type I interferon production upon double-stranded DNA (dsDNA) or cGAMP stimulation and decreased resistance to herpes simplex virus 1 (HSV-1) infection. Additionally, TRIM10-deficient mice are more susceptible to HSV-1 infection and exhibit faster melanoma growth. Mechanistically, TRIM10 associates with STING and catalyzes K27- and K29-linked polyubiquitination of STING at K289 and K370, which promotes STING trafficking from the ER to the Golgi apparatus, formation of STING aggregates, and recruitment of TBK1 to STING, ultimately enhancing the STING-dependent type I interferon response. Our study defines TRIM10 as a critical activator in cGAS-STING-mediated antiviral and antitumor immunity.

PRRSV nonstructural protein 11 degrades swine ISG15 by its endoribonuclease activity to antagonize antiviral immune response.

Porcine reproductive and respiratory syndrome virus (PRRSV) is an enveloped positive-stranded RNA virus which causes serious economic losses to pig industry worldwide. Type I IFN induces expression of interferon-stimulated genes 15 (ISG15) to inhibit virus replication. To survive in the host, PRRSV has evolved to antagonize the antiviral response of ISGylation. Previous studies have reported that nonstructural protein 2 of PRRSV inhibits the ISGylation and antiviral function of ISG15 depending on its ovarian tumor (OTU) domain/papain-like protease domain (PLP2). However, whether there are other PRRSV proteins inhibiting ISGylation of cellular proteins is less well understood. In this study, we first found that PRRSV Nsp11 decreased ISGylation of cellular proteins. Meanwhile, the expression level of ISG15 was significantly inhibited by Nsp11. Further mechanistic studies demonstrated that the transcription of ISG15 was reduced by endoribonuclease activity of Nsp11. Finally, we found that the Nsp11-induced degradation of ISG15 was partially relied on autophagy-lysosome system. Taken together, PRRSV Nsp11 antagonizes the antiviral response of ISG15 by its endoribonuclease activity to promote PRRSV replication. Our results reveal a novel mechanism that PRRSV inhibits ISGylation of cellular proteins and impairs host innate immune response.

Prognostic significance of serum CA125 in the overall management for patients with gastrointestinal stromal tumors.

BACKGROUND: Carbohydrate antigen 125 (CA125) is elevated as a tumor marker in many carcinomas, but its association with gastrointestinal stromal tumor (GIST) has received less attention. This study intends to evaluate whether CA125 level can predict tumor progression and overall survival (OS) of GIST patients. METHODS: We retrospectively analyzed the clinical data and follow-up records of GIST patients who underwent surgical resection in Nanjing Drum Tower Hospital from August 2010 to December 2020. All patients were classified according to serum CA125 level. The relationship between CA125 and clinical outcomes was then examined. RESULTS: A total of 406 GIST patients were enrolled in this study, among which 46 patients had preoperative elevated serum CA125 level and 13 patients with high CA125 level both preoperative and postoperative were observed. Preoperative CA125 concentration was significantly related to rupture status, resection style, tumor site, tumor size, mitotic index, NIH risk grade and c-kit exons. According to Kaplan-Meier curve analysis, high expression of postoperative CA125 was significantly correlated with worse progression-free survival (PFS) and OS among patients with preoperative elevated CA125 level. Ultimately, Cox proportional regression model analysis revealed that increase of preoperative and concurrent postoperative CA125 concentration was an independent predictive factor for PFS. CONCLUSIONS: The concurrent abnormality of serum CA125 before and after operation was an independent risk factor for GIST progression, suggesting its significance as a serum biomarker in the overall management of GIST patients.

Molecular and cellular mechanisms underlying postoperative paralytic ileus by various immune cell types.

Postoperative ileus (POI) is a well-known complication following gut manipulation or surgical trauma, leading to an impaired gut motility and prolonged postoperative recovery time. Few current therapeutic strategies can prevent POI, and this disorder remains to be a major clinical challenge for patients undergoing surgery. Comprehensive understanding of cellular and molecular mechanisms related to the pathogenesis of POI stimulates the discovery of more promising targets for treatment. POI is closely associated with a series of inflammatory events within the bowel wall, and as key components of inflammatory mechanisms, different types of immune cells, including macrophages, dendritic cells, and T lymphocytes, play significant roles during the development of POI. A variety of immune cells are recruited into the manipulation sites after surgery, contributing to early inflammatory events or impaired gut motility. Our review intends to summarize the specific relationship between different immune cells and POI, mainly focusing on the relevant mechanisms underlying this disorder.

Multiple-Site SUMOylation of FMDV 3C Protease and Its Negative Role in Viral Replication.

Protein SUMOylation represents an important cellular process that regulates the activities of numerous host proteins as well as of many invasive viral proteins. Foot-and-mouth disease virus (FMDV) is the first animal virus discovered. However, whether SUMOylation takes place during FMDV infection and what role it plays in FMDV pathogenesis have not been investigated. In the present study, we demonstrated that SUMOylation suppressed FMDV replication by small interfering RNA (siRNA) transfection coupled with pharmaceutical inhibition of SUMOylation, which was further confirmed by increased virus replication for SUMOylation-deficient FMDV with mutations in 3C protease, a target of SUMOylation. Moreover, we provided evidence that four lysine residues, Lys-51, -54, -110, and -159, worked together to confer the SUMOylation to the FMDV 3C protease, which may make SUMOylation of FMDV 3C more stable and improve the host's chance of suppressing the replication of FMDV. This is the first report that four lysine residues can be alternatively modified by SUMOylation. Finally, we showed that SUMOylation attenuated the cleavage ability, the inhibitory effect of the interferon signaling pathway, and the protein stability of FMDV 3C, which appeared to correlate with a decrease in FMDV replication. Taken together, the results of our experiments describe a novel cellular regulatory event that significantly restricts FMDV replication through the SUMOylation of 3C protease. IMPORTANCE FMD is a highly contagious and economically important disease in cloven-hoofed animals. SUMOylation, the covalent linkage of a small ubiquitin-like protein to a variety of substrate proteins, has emerged as an important posttranslational modification that plays multiple roles in diverse biological processes. In this study, four lysine residues of FMDV 3C were found to be alternatively modified by SUMOylation. In addition, we demonstrated that SUMOylation attenuated FMDV 3C function through multiple mechanisms, including cleavage ability, the inhibitory effect of the interferon signaling pathway, and protein stability, which, in turn, resulted in a decrease of FMDV replication. Our findings indicate that SUMOylation of FMDV 3C serves as a host cell defense against FMDV replication. Further understanding of the cellular and molecular mechanisms driving this process should offer novel insights to design an effective strategy to control the dissemination of FMDV in animals.

Microfluidic device engineered to study the trafficking of multiple myeloma cancer cells through the sinusoidal niche of bone marrow.

Multiple myeloma (MM) is an incurable B cell malignancy characterized by the accumulation of monoclonal abnormal plasma cells in the bone marrow (BM). It has been a significant challenge to study the spatiotemporal interactions of MM cancer cells with the embedded microenvironments of BM. Here we report a microfluidic device which was designed to mimic several physiological features of the BM niche: (1) sinusoidal circulation, (2) sinusoidal endothelium, and (3) stroma. The endothelial and stromal compartments were constructed and used to demonstrate the device's utility by spatiotemporally characterizing the CXCL12-mediated egression of MM cells from the BM stroma and its effects on the barrier function of endothelial cells (ECs). We found that the egression of MM cells resulted in less organized and loosely connected ECs, the widening of EC junction pores, and increased permeability through ECs, but without significantly affecting the number density of viable ECs. The results suggest that the device can be used to study the physical and secreted factors determining the trafficking of cancer cells through BM. The sinusoidal flow feature of the device provides an integral element for further creating systemic models of cancers that reside or metastasize to the BM niche.

Knockout of p53 leads to a significant increase in ALV-J replication.

Avian leukemia is a common malignant disease, and and its regulatory mechanism is complex. As the most extensive tumor suppressor gene in cancer research, p53 can control multiple functions such as that of DNA repair, induction of apoptosis, cell cycle arrest and so on. In view of the diversity associated with varied function of p53, this study analyzed the possible effect of gene on ALV-J replication and its regulatory mechanism. We successfully constructed a p53 knockout DF-1 cell line (p53-KO-DF-1 cells) by using CRISPR-Cas9 system. When ALV-J was co-infected with DF-1 and p53-KO-DF-1 cells, it was found that compared with wild-type DF-1 cells, the viral copy number of p53-KO-DF-1 cells infected with ALV-J increased significantly 48 h after infection, whereas the expression of innate immune factors such as Il-2,TNF- α, IFN- γ and MX1 decreased significantly. Detection of p53-related tumor genes indicated that after p53 deletion, the expression of c-myc, bcl-2, and bak increased significantly, while the expression of p21 and p27 was noted to be decreased. The cell cycle distribution and apoptosis of the 2 cell lines was detected by flow cytometry analysis. The results showed that p53 knockout prevented G0/G1 and G2 M phase arrest induced by ALV-J, and substantially decreased the rate of apoptosis. Overall, the results indicated that p53 gene can effectively inhibits ALV-J replication by regulating important cellular processes, and p53 gene related proteins involved in cell cycle activity may function as the key targets for the prevention and treatment of ALV-J.

TRIM31 facilitates K27-linked polyubiquitination of SYK to regulate antifungal immunity.

Spleen tyrosine kinase (SYK) is a non-receptor tyrosine kinase, which plays an essential role in both innate and adaptive immunity. However, the key molecular mechanisms that regulate SYK activity are poorly understood. Here we identified the E3 ligase TRIM31 as a crucial regulator of SYK activation. We found that TRIM31 interacted with SYK and catalyzed K27-linked polyubiquitination at Lys375 and Lys517 of SYK. This K27-linked polyubiquitination of SYK promoted its plasma membrane translocation and binding with the C-type lectin receptors (CLRs), and also prevented the interaction with the phosphatase SHP-1. Therefore, deficiency of Trim31 in bone marrow-derived dendritic cells (BMDCs) and macrophages (BMDMs) dampened SYK-mediated signaling and inhibited the secretion of proinflammatory cytokines and chemokines against the fungal pathogen Candida albicans infection. Trim31-/- mice were also more sensitive to C. albicans systemic infection than Trim31+/+ mice and exhibited reduced Th1 and Th17 responses. Overall, our study uncovered the pivotal role of TRIM31-mediated K27-linked polyubiquitination on SYK activation and highlighted the significance of TRIM31 in anti-C. albicans immunity.

Hsa_circ_0069094 knockdown inhibits cell proliferation, migration, invasion and glycolysis, while induces cell apoptosis by miR-661/HMGA1 axis in breast cancer.

Circular RNAs (circRNAs) are revealed to regulate breast cancer progression. This study aimed to investigate hsa_circ_0069094-mediated effects on breast cancer cell malignancy. Quantitative real time PCR was employed to evaluate the expressions of hsa_circ_0069094, miR-661 and high mobility group A1 (HMGA1). Western blot was performed to determine the protein expression of HMGA1 and proliferating cell nuclear antigen. Breast cancer malignant progressions were explained by cell counting kit-8 proliferation, cell colony formation, flow cytometry analysis, wound-healing and transwell assays. Cell glycolysis was assessed by detecting glucose take, lactate production and hexokinase 2 (HK2) protein level. The target relationship between miR-661 and hsa_circ_0069094 or HMGA1 was predicted by circular RNA interactome and targetscan online databases, and identified by dual-luciferase reporter and RNA immunoprecipitation assay. The effects of hsa_circ_0069094 knockdown on breast cancer growth in vivo were elucidated by in vivo tumor formation assay. Hsa_circ_0069094 and HMGA1 expression were significantly upregulated, while miR-661 expression level was downregulated in breast cancer tissues and cells relative to adjacent normal breast tissues or MCF-10A cells. Functionally, hsa_circ_0069094 knockdown inhibited cell glycolysis, proliferation, migration and invasion, whereas induced cell apoptosis in breast cancer, which was decreased by miR-661 inhibitor. Mechanistically, hsa_circ_0069094 regulated HMGA1 by sponging miR-661. Furthermore, hsa_circ_0069094 knockdown repressed tumor formation in vivo. Collectively, hsa_circ_0069094 knockdown repressed breast cancer cell carcinogenesis and cell glycolysis by regulating HMGA1 through sponging miR-661, which provided a new insight for studying the mechanism of hsa_circ_0069094 in modulating breast cancer development.

Interleukin 3-induced GITR promotes the activation of human basophils.

Human basophils regulate allergic reactions by secreting histamine, interleukin 4 (IL-4) and IL-13 through key surface receptors FcεRI as well as IL-3R, which are constitutively expressed on basophils. IL-3/IL-3R signaling axis plays key roles in regulating the development and activation of basophils. We and others have shown that IL-3-induced surface receptors e.g. ST2, IL-17RB and IL-2 receptors regulate the biology of basophils. However, the expression and function of IL-3-induced surface proteins on human basophils remain to be elucidated. We in this study aimed to identify new basophil activation regulators by transcriptomic analysis of IL-3-stimulated basophils. Gene expression microarray analysis of IL-3-treated basophils revealed 2050 differentially expressed genes, of which 323 genes encoded surface proteins including GITR. We identified that GITR was preferentially induced by IL-3 rather than anti-IgE, IL-33, fMLP and C5a. IL-3-induced GITR was suppressed by inhibitors targeting JAK2, PI3K and MEK1/2. Stimulation of IL-3-treated basophils by GITR enhanced the expression of IL-4 and IL-13. Moreover, IgE-mediated degranulation was enhanced by GITRL in the presence of IL-3. This transcriptomic analysis of IL-3-activated basophils helps to identify novel activation regulator. IL-3-induced GITR promoted the activation of basophils, adding new evidence supporting GITR as an important player in Th2-associated immune responses.

Prognostic significance of TPX2 and NIBP in esophageal cancer.

The expression of targeting protein for Xenopus kinesin-like protein 2 (TPX2) and NIK-IKK-ß binding protein (NIBP) in patients with esophageal cancer were investigated. A total of 250 samples of cancer tissue and 250 samples of adjacent normal tissue were collected from 250 patients who underwent radical resection of esophageal cancer in Weihai Central Hospital from March 2011 to February 2014. RT-qPCR was used to detect the relative expression of TPX2 and NIBP. The relative expression of TPX2 and NIBP in esophageal cancer tissues was statistically higher than those in adjacent normal tissues (P<0.05). TPX2 and NIBP levels in tumor tissues with lymph node metastasis were significantly higher than those in tissues without lymph node metastasis (P<0.05). There was a significant difference in the relative expression of TPX2 and NIBP in different degrees of infiltration (P<0.05). Tissues with a TPX2 level equal to or higher than the average TPX2 level (1.465) were divided into TPX2 high expression group, while tissues with a TPX2 level below the average were divided into TPX2 low expression group. The 5-year overall survival rate of TPX2 high expression group was significantly lower than that of TPX2 low expression group (P<0.05). Tissues with a NIBP level equal to or higher than the average NIBP level (0.498) were included in the NIBP high expression group, while tissues with a NIBP level below the average were included in the NIBP low expression group. The 5-year overall survival rate of NIBP high expression group was significantly lower than that of NIBP low expression group (P<0.05). TPX2, NIBP, TNM staging, lymph node metastasis, and degree of infiltration were independent prognostic factors affecting overall survival (P<0.05). In conclusion, owing to their high expression in esophageal cancer tissues, TPX2 and NIBP are potentially important biomarkers for the evaluation of TNM stage, metastasis, and prognosis of esophageal cancer.

Characterization of a moderately pathogenic pseudorabies virus variant isolated in China, 2014.

In this study, we reported a moderately pathogenic pseudorabies virus (PRV) variant isolated from one Bartha-K61-vaccinated pig farm in Weifang, Shandong Province, China, 2014. The sick piglets in the farm were characterized by anorexia, weight loss and neurologic symptoms but did not die. Sequence alignment of the gE gene indicated that it belonged to a new mutated PRV strain and about 15% amino acid sites had mutations, deficiencies and insertions compared to the other PRV strains. The gD gene had two amino acid insertions and ten amino acid mutations in comparison with the Bartha-K61 vaccine strain. The TK and gM genes were the same as one highly pathogenic PRV TJ strain. Evidence from virus isolation, laboratory challenge, serological detection and histopathologic examination confirmed that the etiological agent of the disease is PRV SD1404, which is a moderately pathogenic strain and causes piglets to be sick but not to die. PRV SD1404 strain is different from other reports and should be paid more attention to avoid economic losses.

[Cloning and tissue expression of 4-coumarate coenzyme A ligase gene in Angelica sinensis].

4-coumarate coenzyme A ligase is a key enzyme of phenylpropanoid metabolic pathway in higher plant and may regulate the biosynthesis of ferulic acid in Angelica sinensis. In this study, the homology-based cloning and rapid amplification of cDNA ends (RACE) technique were used to clone a full length cDNA encoding 4-coumarate coenzyme A ligase gene (4CL), and then qRT-PCR was taken for analyzing 4CL gene expression levels in the root, stem and root tissue at different growth stages of seedlings of A. sinensis. The results showed that a full-length 4CL cDNA (1,815 bp) was obtained (GenBank accession number: KT880508) which shares an open reading frame (ORF) of 1 632 bp, encodes 544 amino acid polypeptides. We found 4CL gene was expressed in all tissues including leaf, stem and root of seedlings of A. sinensis. The expressions in the leave and stem were increased significantly with the growth of seedlings of A. sinensis (P < 0.05), while it in the root showed little change. It indicates a time-space pattern of 4CL gene expression in seedlings of A. sinensis. These findings will be useful for establishing an experiment basis for studying the structure and function of 4CL gene and elucidating mechanism of ferulic acid biosynthesis and space-time regulation in A. sinensis.

Characterization of Cr(V)-induced genotoxicity using CdTe nanocrystals as fluorescent probes.

CdTe nanocrystals capped by cysteamine were synthesized to study Cr(V)-induced genotoxicity. On the surface of TiO2 thin films, the stepwise process of DNA breakage induced by Cr(V)-GSH complexes was vividly observed by using CdTe-DNA self-assembled fluorescent probes; in acetate buffer solution, an analytical method was developed to detect Cr(V)-induced genotoxicity with CdTe fluorescent probes.