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1.
Cancer Lett ; 598: 217087, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38964732

ABSTRACT

Human appendix is critical for the maintenance of intestinal homeostasis. Appendicectomy has been the optimal treatment of acute appendicitis, yet the cancer incidence after appendix removal remains unclear. In this territory-wide retrospective cohort study, adult participants who underwent appendicectomy from 2000 to 2018 were retrieved from a population database (n = 43,983), while matched reference participants were retrieved as controls (n = 85,853). After appendicectomy, the overall cancer risk was significantly increased (subdistribution hazard ratio (SHR) = 1.124) compared to the non-appendicectomy group. Appendicectomy-treated males had higher cancer risk than males without appendicectomy (SHR = 1.197), while such difference was not observed in female participants. Significant increase in cancer risk was also observed in elder participants (age >60) with appendicectomy (SHR = 1.390). Appendicectomy was positively correlated with the risk of digestive tract and respiratory cancers including colon (SHR = 1.440), pancreas (SHR = 1.930), and trachea, bronchus, and lung (SHR = 1.394). In contrast, the risk of liver cancer was markedly decreased after appendicectomy (SHR = 0.713). In conclusion, we reported the association of appendicectomy with subsequent cancer incidence. These findings highlight the potential complication after appendix removal and the necessity of post-operative management to monitor and prevent long-term adverse events.

2.
Environ Pollut ; 358: 124507, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38968984

ABSTRACT

Nitrate and Cr(VI) are the typical and prevalent co-contaminants in the groundwater, how to synchronously and effectively diminish them has received growing attention. The most problem that currently limits the nitrate and Cr(VI) reduction technology for groundwater remediation is with emphasis on exploring the optimal electron donors. This study investigated the feasibility of utilizing the synergistical effect of inorganic electron donors (pyrite, sulfur) and inherently limited organics to promote synchronous nitrate and Cr(VI) removal, which meets the requirement of naturally low-carbon and eco-friendly technologies. The NO3--N and Cr(VI) removal efficiencies in the pyrite and sulfur involved mixotrophic biofilter (PS-BF: approximately 90.8 ± 0.6% and 99.1 ± 2.1%) were substantially higher than that in a volcanic rock supported biofilter (V-BF: about 49.6% ± 2.8% and 50.0% ± 9.3%), which was consistent with the spatial variations of their concentrations. Abiotic and biotic batch tests directly confirmed the decisive role of pyrite and sulfur for NO3--N and Cr(VI) removal via chemical and microbial pathways. A server decline in sulfate production correlated with decreasing COD consumption revealed that there was sulfur disproportionation induced by limited organics. Metagenomic analysis suggested that chemoautotrophic microbes like Sulfuritalea and Thiobacillus were key players responsible for sulfur oxidation, nitrate and Cr(VI) reduction. The metabolic pathway analysis suggested that genes encoding functional enzymes related to complete denitrification, S oxidation, and dissimilatory sulfate reduction were upregulated, however, genes encoding Cr(VI) reduction enzymes (e.g. chrA, chrR, nemA, and azoR) were downregulated in PS-BF, which further explained the synergistical effect of multiple electron donors. These findings provide insights into their potential cooperative interaction of multiple electron donors on greatly promoting nitrate and Cr(VI) removal and have implications for the remediation technology of nitrate and Cr(VI) co-contaminated groundwater.

3.
Nat Commun ; 15(1): 427, 2024 Jan 10.
Article in English | MEDLINE | ID: mdl-38199995

ABSTRACT

The microbiome in a specific human organ has been well-studied, but few reports have investigated the multi-organ microbiome as a whole. Here, we aim to analyse the intra-individual inter-organ and intra-organ microbiome in deceased humans. We collected 1608 samples from 53 sites of 7 surface organs (oral cavity, esophagus, stomach, small intestine, appendix, large intestine and skin; n = 33 subjects) and performed microbiome profiling, including 16S full-length sequencing. Microbial diversity varied dramatically among organs, and core microbial species co-existed in different intra-individual organs. We deciphered microbial changes across distinct intra-organ sites, and identified signature microbes, their functional traits, and interactions specific to each site. We revealed significant microbial heterogeneity between paired mucosa-lumen samples of stomach, small intestine, and large intestine. Finally, we established the landscape of inter-organ relationships of microbes along the digestive tract. Therefore, we generate a catalogue of bacterial composition, diversity, interaction, functional traits, and bacterial translocation in human at inter-organ and intra-organ levels.


Subject(s)
Appendix , Microbiota , Humans , Bacterial Translocation , Stomach , Microbiota/genetics , Mouth
4.
Sci Rep ; 14(1): 2180, 2024 01 25.
Article in English | MEDLINE | ID: mdl-38273073

ABSTRACT

Tumor budding is a long-established independent adverse prognostic marker for colorectal cancer (CRC), yet assessment of tumor budding was not reproducible. Therefore, development of precise diagnostic approaches to tumor budding is in demand. In this study, we first performed bioinformatic analysis in our single-center CRC patients' cohort (n = 84) and identified tumor budding-associated hub genes using the weighted gene co-expression network analysis (WGCNA). A machine learning methodology was used to identify hub genes and construct a prognostic signature. Nomogram model was used to identified hub genes score for tumor budding, and the receiver operating characteristic (ROC) curve and calibration plot indicated high accuracy and stability of hub gene score for predicted the prognosis of CRC. The association between budding-associated hub genes and score and prognosis of CRC were further verified in TCGA CRC cohort (n = 342). Then gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were applied to explore the signaling pathways related to the tumor budding and validated by immunohistochemistry (IHC) of our clinical samples. Subsequently, immune infiltration analysis demonstrated that there was a high correlation between hub genes score and M2-like macrophages infiltrated in tumor tissue. In addition, somatic mutation and chemotherapeutic response prediction were analyzed based on the risk signature. In summary, we established a tumor budding diagnostic molecular model, which can improve tumor budding assessment and provides a promising novel molecular marker for immunotherapy and prognosis of CRC.


Subject(s)
Colorectal Neoplasms , Immunotherapy , Humans , Prognosis , Nomograms , Calibration , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/genetics , Colorectal Neoplasms/therapy
5.
Opt Lett ; 48(20): 5363-5366, 2023 Oct 15.
Article in English | MEDLINE | ID: mdl-37831868

ABSTRACT

We demonstrate a temperature-insensitive fiber-delay-line-stabilized (FDL-stabilized) laser based on a dual Mach-Zehnder interferometer (MZI) by using polarization maintaining fibers (PMFs). Two orthogonal polarization components of a beam are simultaneously transmitted in the interferometer. Each polarization component exhibits a unique phase shift in response to the changes in temperature, forming a dual MZI. One of the heterodyne signals is used to lock the laser frequency, while the other one is used to compensate the frequency change induced by the temperature fluctuation. The experiment shows that the laser frequency fluctuation has been suppressed at least 25 times. This is an effective method to reduce the laser frequency noise induced by the temperature fluctuation of the FDL. In this way, a compact system with less thermal shields can be realized, and the thermal equilibrium time could be decreased dramatically.

6.
Oncogene ; 42(13): 941-951, 2023 03.
Article in English | MEDLINE | ID: mdl-36859558

ABSTRACT

Extrachromosomal circular DNA (ecDNA) has gained renewed interest since its discovery more than half a century ago, emerging as critical driver of tumor evolution. ecDNA is highly prevalent in many types of cancers, including colorectal cancer (CRC), which is one of the most deadly cancers worldwide. ecDNAs play an essential role in regulating oncogene expression, intratumor heterogeneity, and resistance to therapy independently of canonical chromosomal alterations in CRC. Furthermore, the existence of ecDNAs is attributed to the patient's prognosis, since ecDNA-based oncogene amplification adversely affects clinical outcomes. Recent understanding of ecDNA put an extra layer of complexity in the pathogenesis of CRC. In this review, we will discuss the current understanding on mechanisms of biogenesis, and distinctive features of ecDNA in CRC. In addition, we will examine how ecDNAs mediate oncogene overexpression, gene regulation, and topological interactions with active chromatin, which facilitates genetic heterogeneity, accelerates CRC malignancy, and enhances rapid adaptation to therapy resistance. Finally, we will discuss the potential diagnostic and therapeutic implications of ecDNAs in CRC.


Subject(s)
Colorectal Neoplasms , Neoplasms , Humans , DNA , Oncogenes , Neoplasms/genetics , Chromatin , DNA, Circular/genetics , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics
7.
Biomedicines ; 11(3)2023 Mar 13.
Article in English | MEDLINE | ID: mdl-36979860

ABSTRACT

Barrett's esophagus (BE) is a precancerous lesion of esophageal adenocarcinoma (EAC). It is a pathological change in which the squamous epithelium distal esophagus is replaced by columnar epithelium. Loss of P53 is involved in the development of BE and is taken as a risk factor for the progression. We established a HET1A cell line with P53 stably knockdown by adenovirus vector infection, followed by 30 days of successive acidic bile salt treatment. MTT, transwell assay, and wound closure assay were applied to assess cell proliferation and migration ability. The expression of key factors was analyzed by RT-qPCR, western blotting and immunohistochemical staining. Our data show that the protein expression level of P53 reduced after exposure to acidic bile salt treatment, and the P53 deficiency favors the survival of esophageal epithelial cells to accommodate the stimulation of acidic bile salts. Furthermore, exposure to acidic bile salt decreases cell adhesions by repressing the JAK/STAT signaling pathway and activating VEGFR/AKT in P53-deficient esophageal cells. In EAC clinical samples, P53 protein expression is positively correlated with that of ICAM1 and STAT3 and negatively correlated with VEGFR protein expression levels. These findings elucidate the role of P53 in the formation of BE, explain the mechanism of P53 deficiency as a higher risk of progression for BE formation, and provide potential therapeutic targets for EAC.

8.
Oncogene ; 42(7): 530-540, 2023 02.
Article in English | MEDLINE | ID: mdl-36539569

ABSTRACT

Appendectomy impacts the homeostasis of gut microbiome in patients. We aimed to study the role of appendectomy in colorectal cancer (CRC) risk through causing gut microbial dysbiosis. Population-based longitudinal study (cohort 1, n = 129,155) showed a 73.0% increase in CRC risk among appendectomy cases throughout 20 years follow-up (Adjusted sub-distribution hazard ratio (SHR) 1.73, 95% CI 1.49-2.01, P < 0.001). Shotgun metagenomic sequencing was performed on fecal samples from cohort 2 (n = 314). Gut microbial dysbiosis in appendectomy subjects was observed with significant enrichment of 7 CRC-promoting bacteria (Bacteroides vulgatus, Bacteroides fragilis, Veillonella dispar, Prevotella ruminicola, Prevotella fucsa, Prevotella dentalis, Prevotella denticola) and depletion of 5 beneficial commensals (Blautia sp YL58, Enterococcus hirae, Lachnospiraceae bacterium Choco86, Collinsella aerofaciens, Blautia sp SC05B48). Microbial network analysis showed increased correlation strengths among enriched bacteria and their enriched oncogenic pathways in appendectomy subjects compared to controls. Of which, B. fragilis was the centrality in the network of the enriched bacteria. We further confirmed that appendectomy promoted colorectal tumorigenesis in mice by causing gut microbial dysbiosis and impaired intestinal barrier function. Collectively, this study revealed appendectomy-induced microbial dysbiosis characterized by enriched CRC-promoting bacteria and depleted beneficial commensals, signifying that the gut microbiome may play a crucial role in CRC development induced by appendectomy.


Subject(s)
Colorectal Neoplasms , Gastrointestinal Microbiome , Animals , Mice , Gastrointestinal Microbiome/genetics , Dysbiosis/microbiology , Appendectomy/adverse effects , Longitudinal Studies , Colorectal Neoplasms/genetics , Colorectal Neoplasms/microbiology
9.
Chem Biol Interact ; 368: 110248, 2022 Dec 01.
Article in English | MEDLINE | ID: mdl-36343684

ABSTRACT

UGT1A1 is the main enzyme that catalyzes the metabolic elimination and detoxification of SN-38, the active form of the drug irinotecan. Milk thistle products have been used widely to protect the liver from injury associated with the use of chemotherapeutic agents. To evaluate whether SN-38 metabolism can be affected by milk thistle products, the inhibitory effects of silybins on UGT1A1*1 and UGT1A1*6 were evaluated in the present investigation. Both silybin A and silybin B potently inhibited SN-38 glucuronidation catalyzed by UGT1A1*1 or UGT1A1*6. It was noteworthy that silybin A and silybin B showed synergistic effect in UGT1A1*1 microsomes at concentration around IC50, while additive effect in UGT1A1*6. According to the predicted AUCi/AUC ratios (the ratio of the area under the plasma concentration-time curve of SN-38 in the presence and absence of silybins), the coadministration of irinotecan and several milk thistle products, including silybin-phosphatidylcholine complex, two Legalon capsules, four Silymarin tablets or four Liverman capsules, may lead to clinically significant herb-drug interactions (HDI) via UGT1A1 inhibition. Meanwhile, Rgut values were much higher than 11 in all the groups, indicating potential HDI due to intestinal UGT1A1 inhibition.


Subject(s)
Glucuronosyltransferase , Silybum marianum , Irinotecan/metabolism , Silybin/metabolism , Silybin/pharmacology , Glucuronosyltransferase/metabolism , Microsomes, Liver/metabolism , Catalysis , Camptothecin
10.
Int J Clin Pharmacol Ther ; 60(3): 146-158, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34846299

ABSTRACT

OBJECTIVE: Previous clinical studies and meta-analyses have shown controversial results on the association between C3435T polymorphism of the ABCB1 gene and anti-epileptic drug (AED) resistance. Based on the fact that sample size and confounding factors could contribute to the inconsistency, we performed an updated meta-analysis by including the most recent studies, and subgroup analysis was conducted to evaluate the effect of confounding factors on the association. MATERIALS AND METHODS: We searched articles in 6 electronic databases including PubMed, Medline, Embase, Web of science, Cochrane Library, CNKI (China National Knowledge Infrastructure) for relevant articles up to June 2020. RESULTS: The current analysis showed that the C allele of C3435T variant was a risk factor for drug resistance in the overall populations (C allele vs. T allele, OR: 1.13; 95% CI: 1.02 - 1.25; p = 0.02) and in the Caucasians (C allele vs. T allele, OR: 1.09; 95% CI: 1.09 - 1.43; p = 0.002), while no association was observed in Asians and Indians. Particularly, our study reported for the first time that the 3435T allele was more common in epilepsy patients with drug resistance in the Tunisian population (C allele vs. T allele, OR: 0.31; 95% CI: 0.15 - 0.65; p = 0.002). In addition, our present analysis suggested an association between C3435T and AED resistance in cryptogenic, symptomatic, but not in idiopathic patients. Subgroup studies based on age and gender showed no association. CONCLUSION: AED resistance in Caucasian and Tunisian populations may benefit from ABCB1 C3435T genotyping. We recommend that more details, such as gender and etiology of epilepsy, should be taken into account to draw a reliable conclusion in future studies.


Subject(s)
Anticonvulsants , Epilepsy , ATP Binding Cassette Transporter, Subfamily B/genetics , Anticonvulsants/adverse effects , Asian People/genetics , Drug Resistance/genetics , Epilepsy/drug therapy , Epilepsy/genetics , Genetic Predisposition to Disease , Humans , Polymorphism, Single Nucleotide
11.
Foods ; 12(1)2022 Dec 20.
Article in English | MEDLINE | ID: mdl-36613222

ABSTRACT

Monitoring of the quality change of cherry tomatoes during storage is very important for the quality control of cherry tomatoes. In this study, the soluble solids content (SSC), reducing sugars (RSs), titratable acids (TAs), ascorbic acid (AA) and lycopene of cherry tomatoes during storage at 0, 4, 10 or 25 °C were measured, and the kinetic models were established. The results showed that the zero-order reaction combined with the Arrhenius kinetic model could be used for the prediction of changes in SS, RS and AA content. The first-order reaction combined with the Arrhenius kinetic model could be used for the prediction of changes in the TA and lycopene content. The volatile compounds of cherry tomatoes were simultaneously determined by the gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-nose). A total of 104 volatile compounds were identified by GC-MS. Orthogonal partial least squares discriminant analysis (OPLS-DA) showed that there were 13 different metabolites among cherry tomatoes with different freshness. The accuracies of Fisher's models based on E-nose for discriminating freshness of cherry tomatoes stored at 0, 4, 10 and 25 °C were 96%, 100%, 92% and 90%, respectively. This study provides a theoretical basis for the quality control of cherry tomatoes during storage.

12.
J Biosci ; 452020.
Article in English | MEDLINE | ID: mdl-32661211

ABSTRACT

Mitochondria-derived reactive oxygen species (mROS) are produced at a variety of sites and affect the function of bio-molecules. The anti-oxidant system from both mitochondria and cytosol tightly coordinate to maintain the redox balance of cells and reduce damage from mROS. Mitochondrial DNA (mtDNA) are highly susceptible to mROS, and are easily oxidized to accumulate DNA modifications. Frequent oxidative damages in mtDNA have been associated with neurological degeneration, inflammasomes, tumorigenesis, and malignant progression. Among mitochondrial DNA repair pathways, the base excision repair pathway has been extensively characterized to remove some of oxidative damages in mtDNA as efficiently as the nuclear base excision repair. The implications of other pathways remain unclear. This review focuses on: (i) Sources of mROS and the antioxidant system to balance redox status; (ii) major mtDNA lesions or damages from mROS-mediated oxidation and the reported repair pathways or repairing factors; (iii) cellular response of oxidized mtDNA and methods to identify oxidatively generated DNA modifications in pathological conditions. DNA damages caused by mROS have been increasingly implicated in diseases and aging, and thus we critically discuss methods of the oxidative modifications evaluation and the complexity of non-canonical DNA repair pathways in mitochondria.


Subject(s)
DNA, Mitochondrial/genetics , Mitochondria/metabolism , Oxidative Stress/genetics , Reactive Oxygen Species/adverse effects , Aging/genetics , Aging/metabolism , Aging/pathology , Cell Nucleus/drug effects , Cell Nucleus/genetics , DNA Damage/drug effects , DNA Damage/genetics , DNA Repair/drug effects , DNA Repair/genetics , DNA, Mitochondrial/metabolism , Humans , Mitochondria/genetics , Oxidation-Reduction , Oxidative Stress/drug effects , Reactive Oxygen Species/metabolism , Signal Transduction/drug effects
13.
Semin Cancer Biol ; 56: 37-46, 2019 06.
Article in English | MEDLINE | ID: mdl-28993206

ABSTRACT

Eph receptors and their Eph receptor-interacting (ephrin) ligands together form an important cell communication system with diverse roles. Experimental evidence demonstrated Eph receptor bidirectional signaling with both tumor-suppressing and tumor-promoting activities in cancer cells. The tyrosine kinase EphB4, a member of the Eph receptor family, has been associated with tumor angiogenesis, growth and metastasis, thus making it a valuable and attractive target for drug design for therapeutic applications. In the past decade, many studies have focused on elucidating the structure and function of EphB4 in complex with its ligand ephrinB2 for their role in carcinogenesis. Meanwhile, an array of compounds targeting EphB4 have been studied and several selective inhibitors have been tested in clinical studies. This review discusses the structure and function of the EphB4 receptor, analyzes its potential as a target for anticancer therapy, and summarizes the information about inhibitors of EphB4 kinase activity. Conclusively, EphB4 is a challenging but promising therapeutic target in cancer.


Subject(s)
Molecular Targeted Therapy , Neoplasms/drug therapy , Neoplasms/metabolism , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Receptor, EphB4/antagonists & inhibitors , Receptor, EphB4/metabolism , Animals , Biomarkers, Tumor , Gene Expression Regulation, Neoplastic/drug effects , Humans , Neoplasms/etiology , Neoplasms/pathology , Receptor, EphB4/chemistry , Receptor, EphB4/genetics , Signal Transduction/drug effects , Structure-Activity Relationship
14.
Adv Sci (Weinh) ; 5(6): 1700964, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29938175

ABSTRACT

Clinical evidence indicates that drug resistance is a great obstacle in breast cancer therapy. It renders the disease uncontrollable and causes high mortality. Multiple mechanisms contribute to the development of drug resistance, but the underlying cause is usually a shift in the genetic composition of tumor cells. It is increasingly feasible to engineer the genome with the clustered regularly interspaced short palindromic repeats (CRISPR)/associated (Cas)9 technology recently developed, which might be advantageous in overcoming drug resistance. This article discusses how the CRISPR/Cas9 system might revert resistance gene mutations and identify potential resistance targets in drug-resistant breast cancer. In addition, the challenges that impede the clinical applicability of this technology and highlight the CRISPR/Cas9 systems are presented. The CRISPR/Cas9 system is poised to play an important role in preventing drug resistance in breast cancer therapy and will become an essential tool for personalized medicine.

15.
EMBO J ; 37(6)2018 03 15.
Article in English | MEDLINE | ID: mdl-29440226

ABSTRACT

Human telomerase synthesizes telomeric DNA repeats (GGTTAG)n onto chromosome ends using a short template from its integral telomerase RNA (hTR). However, telomerase is markedly slow for processive DNA synthesis among DNA polymerases. We report here that the unique template-embedded pause signal restricts the first nucleotide incorporation for each repeat synthesized, imparting a significantly greater KM This slow nucleotide incorporation step drastically limits repeat addition processivity and rate under physiological conditions, which is alleviated with augmented concentrations of dGTP or dGDP, and not with dGMP nor other nucleotides. The activity stimulation by dGDP is due to nucleoside diphosphates functioning as substrates for telomerase. Converting the first nucleotide of the repeat synthesized from dG to dA through the telomerase template mutation, hTR-51U, correspondingly shifts telomerase repeat addition activity stimulation to dATP-dependent. In accordance, telomerase without the pause signal synthesizes DNA repeats with extremely high efficiency under low dGTP concentrations and lacks dGTP stimulation. Thus, the first nucleotide incorporation step of the telomerase catalytic cycle is a potential target for therapeutic enhancement of telomerase activity.


Subject(s)
Nucleotides , Telomerase , HEK293 Cells , Humans , Mutation
16.
Pharmacol Ther ; 163: 24-47, 2016 07.
Article in English | MEDLINE | ID: mdl-27118336

ABSTRACT

The current research on anticancer drugs focuses on exploiting particular traits or hallmarks unique to cancer cells. Telomerase, a special reverse transcriptase, has been recognized as a common factor in most tumor cells, and in turn a distinctive characteristic with respect to non-malignant cells. This feature has made telomerase a preferred target for anticancer drug development and cancer therapy. This review aims to analyze the pharmacological function and mechanism and role of telomerase in oncogenesis; to provide fundamental knowledge for research on the structure, function, and working mechanism of telomerase; to expound the role that telomerase plays in the initiation and development of tumor and its relationship with tumor cell growth, proliferation, apoptosis, and related pathway molecules; and to display potential targets of antitumor drug for inhibiting the expression, reconstitution, and trafficking of the enzyme. We therefore summarize recent advances in potential telomerase inhibitors for antitumor including natural products, synthetic small molecules, peptides and proteins, which indicate that optimizing the delivery method and drug combination could be of help in a combinatorial drug treatment for tumor. More extensive understanding of the structure, biogenesis, and mechanism of telomerase will provide invaluable information for increasing the efficiency of rational antitumor drug design.


Subject(s)
Antineoplastic Agents/pharmacology , Neoplasms/drug therapy , Telomerase/antagonists & inhibitors , Telomere/metabolism , Animals , Biomarkers , Cell Enlargement , Cell Proliferation , Clinical Trials as Topic , Down-Regulation , Drug Delivery Systems , Drug Design , Holoenzymes , Humans , Plant Preparations/pharmacology , RNA, Messenger/metabolism , Ribonucleoproteins/metabolism , Shelterin Complex , Telomere-Binding Proteins/metabolism , Transcription, Genetic/physiology , Up-Regulation
17.
Wei Sheng Wu Xue Bao ; 55(10): 1273-83, 2015 Oct 04.
Article in Chinese | MEDLINE | ID: mdl-26939455

ABSTRACT

OBJECTIVE: To further study physiological functions and structure of ß-glycosidase, we cloned the bglC gene of Bacillus subtilis and expressed it in E. coli BL21 (DE3), followed by the characterization and structural simulation of the enzyme. METHODS: We amplified the bglC gene and transferred it into E. coli BL21 (DE3), then we obtained a mutant with higher hydrolytic activity by directed evolution. After purifying the enzymes through a nickel-nitrilotriacetic acid agarose column, we characterized the wild-type and mutant enzymes. By means of CD spectrum, Native-PAGE and protein 3-D structure modeling, we analyzed the higher structure of the ß-glycosidase. RESULTS: We got one mutant enzyme BS-GLY_M1 (A242T/T385A/S425L) with improved hydrolytic activity by directed evolution and screening. The specific activity of wild-type enzyme was 9.7 U/mg, with optimum temperature at 60 degrees C and optimum pH at 7.0. The specific activity of BS-GLY_M1 was 17. 1U/mg, with optimum temperature at 55 degrees C and optimum pH at 7.0. Moreover, the half-life time of the mutant enzyme at 55 degrees C was 3.5 h, 2 h longer than that of wild-type enzyme. Furthermore, the catalytic efficiency (K(m)/K(cat)) of BS-GLY_M1 on the substrates 4-nitrophenyl-ß-galactoside, lactose, and arbutin improved obviously. The polymer forms of the enzyme under the native conditions were of dimer and tetramer, but the dimer was the most probable functional unit. Result of structural simulation also showed slight changes occurred in the tertiary structure of the mutant enzyme, which may be the main reason for the enhanced thermal stability and catalytic efficiency of BS-GLY _M1. [ CONCLUSION: ß-glycosidase from Bacillus subtilis could be expressed in E. coli BL21 (DE3), meanwhile its hydrolysis efficiency could be further improved by directed evolution.


Subject(s)
Bacillus subtilis/enzymology , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Cloning, Molecular , beta-Galactosidase/chemistry , beta-Galactosidase/genetics , Bacillus subtilis/genetics , Bacterial Proteins/metabolism , Catalysis , Directed Molecular Evolution , Enzyme Stability , Escherichia coli/genetics , Escherichia coli/metabolism , Kinetics , Models, Molecular , Temperature , beta-Galactosidase/metabolism
18.
Proc Natl Acad Sci U S A ; 111(31): 11311-6, 2014 Aug 05.
Article in English | MEDLINE | ID: mdl-24982163

ABSTRACT

Telomerase is a specialized reverse transcriptase (RT) containing an intrinsic telomerase RNA (TR) component. It synthesizes telomeric DNA repeats, (GGTTAG)n in humans, by reiteratively copying a precisely defined, short template sequence from the integral TR. The specific mechanism of how the telomerase active site uses this short template region accurately and efficiently during processive DNA repeat synthesis has remained elusive. Here we report that the human TR template, in addition to specifying the DNA sequence, is embedded with a single-nucleotide signal to pause DNA synthesis. After the addition of a dT residue to the DNA primer, which is specified by the 49 rA residue in the template, telomerase extends the DNA primer with three additional nucleotides and then pauses DNA synthesis. This sequence-defined pause site coincides precisely with the helix paired region 1 (P1)-defined physical template boundary and precludes the incorporation of nontelomeric nucleotides from residues outside the template region. Furthermore, this sequence-defined pausing mechanism is a key determinant, in addition to the P1-defined template boundary, for generating the characteristic 6-nt ladder banding pattern of telomeric DNA products in vitro. In the absence of the pausing signal, telomerase stalls nucleotide addition at multiple sites along the template, generating DNA products with heterogeneous terminal repeat registers. Our findings demonstrate that this unique self-regulating mechanism of the human TR template is essential for high-fidelity synthesis of DNA repeats.


Subject(s)
Telomerase/genetics , Templates, Genetic , Base Pairing , Base Sequence , Biocatalysis , DNA/biosynthesis , Humans , Models, Biological , Molecular Sequence Data , Mutation/genetics , Nucleic Acid Heteroduplexes/genetics , Nucleotides/metabolism , RNA/genetics , RNA/metabolism , Telomerase/metabolism
19.
Fish Shellfish Immunol ; 37(1): 30-7, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24462912

ABSTRACT

The total haemocyte count (THC), differential haemocyte count (DHC), phenoloxidase activity, respiratory bursts (release of superoxide anion), superoxide dismutase activity, and phagocytic activity and clearance efficiency to the pathogen Vibrio alginolyticus were measured when white shrimp, Litopenaeus vannamei, (7.5 ± 0.5 g) were individually injected with diethyl pyrocarbonate-water (DEPC-H2O) or different dsRNA at 3 days of injection. In addition, haemolymph glucose and lactate, and haemocytes crustacean hyperglycemic hormone (CHH), transglutaminase I (TGI), transglutaminase II (TGII) and clottable protein (CP) mRNA expression were determined for the shrimp that received DEPC-H2O and different dsRNA after 3 days, and then transferred to 22 and 28 °C from 28 °C. Results showed that respiratory burst, phagocytic activity and clearance efficiency significantly decreased, but hyaline cells significantly increased in the shrimp received LvTGII dsRNA after 3 days. In hypothermal stress studies, LvTGI and CHH were significantly up-regulated in LvTGII-depleted shrimp following exposure to 28 and 22 °C, and haemolymph glucose and lactate were significantly enhanced in LvTGII-depleted shrimp. The injection of LvTGII dsRNA also significantly increased the mortality of L. vannamei challenged with the pathogen V. alginolyticus. These results suggest that LvTGII is an important component on the immune resistance of shrimp, and is involved in the regulation of some immune parameters and carbohydrate metabolites, as well as has a complementary effect with LvTGI in immunological and physiological response of shrimp.


Subject(s)
GTP-Binding Proteins/immunology , Penaeidae/enzymology , Penaeidae/immunology , Transglutaminases/immunology , Vibrio alginolyticus/immunology , Analysis of Variance , Animals , Blood Cell Count , DNA Primers/genetics , Hemocytes/physiology , Monophenol Monooxygenase/metabolism , Penaeidae/microbiology , Phagocytosis/immunology , Protein Glutamine gamma Glutamyltransferase 2 , Respiratory Burst/immunology , Superoxide Dismutase/metabolism
20.
Arch Pharm Res ; 37(8): 1086-95, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24318305

ABSTRACT

It has been suggested that combined effect of natural products may improve the treatment effectiveness in combating proliferation of cancer cells. Here, we examined the combined anticancer activities of compounds of three natural origin including baicalein, curcumin, and resveratrol with chemotherapy drug paclitaxel respectively, which showed that combination of paclitaxel with curcumin exhibited synergistic growth inhibition and induced significant apoptosis in MCF-7 cell lines. Treatment of MCF-7 cell lines with paclitaxel and curcumin induced the apoptosis of regulatory protein Bcl-2 but decreased Bax expression. In addition, simultaneous treatment with paclitaxel and curcumin strongly inhibited paclitaxel-induced activities of EGFR signaling. Furthermore, the combination of paclitaxel and curcumin exerted increased anti-tumor efficacy on mouse models. Overall, our data described the promising therapeutic potential and underlying mechanisms of combining paclitaxel with curcumin in treating breast cancer.


Subject(s)
Adjuvants, Pharmaceutic/pharmacology , Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis/drug effects , Curcumin/pharmacology , ErbB Receptors/metabolism , Paclitaxel/pharmacology , Signal Transduction/drug effects , Adjuvants, Pharmaceutic/administration & dosage , Adjuvants, Pharmaceutic/therapeutic use , Animals , Antineoplastic Agents, Phytogenic/administration & dosage , Antineoplastic Agents, Phytogenic/therapeutic use , Cell Proliferation/drug effects , Curcumin/administration & dosage , Curcumin/therapeutic use , Drug Synergism , Female , Flow Cytometry , Humans , MCF-7 Cells , Mice, Inbred Strains , Paclitaxel/administration & dosage , Paclitaxel/therapeutic use , Xenograft Model Antitumor Assays
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