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1.
J Hepatocell Carcinoma ; 11: 737-746, 2024.
Article in English | MEDLINE | ID: mdl-38654891

ABSTRACT

Aim: This study aimed to explore the effects of the triglyceride-glucose (TyG) index on hepatocellular carcinoma (HCC) development in patients with hepatitis B virus (HBV)-related liver cirrhosis (LC). Methods: A total of 242 patients with HBV-related LC were enrolled and followed-up. Logistic regression analysis was performed to investigate risk factors for HCC. Results: The median follow-up time was 37 months (range: 6-123 months). At the end of the follow-up, 11 (11.3%) patients with compensated cirrhosis (CC) and 45 (31.0%) with decompensated cirrhosis (DC) developed HCC. The TyG index was higher in the HCC group than in the non-HCC group (P=0.05). Univariate analysis showed that age (P<0.01), DC (P<0.01), TyG index (P=0.08), albumin (ALB) level (P=0.05), platelet (PLT) count (P<0.01), and HBV DNA positivity (P<0.01) were associated with HCC development. Multivariate analysis revealed that age, DC, TyG index, PLT count, and HBV DNA positivity were independent risk factors for HCC development (P=0.01, 0.01, <0.01, 0.05, and <0.01, respectively). For patients with DC, multivariate logistic regression analysis revealed that age, TyG index, and HBV DNA positivity were independent risk factors for HCC development (all P<0.05). A new model encompassing age, DC, TyG, PLT, and positive HBV DNA had optimal predictive accuracy in patients with DC or CC, with a cutoff value of 0.197. The areas under the receiver operating characteristic curves (AUROCs) of the model for predicting HCC development in patients with LC, DC, and CC were 0.778, 0.721, and 0.783, respectively. Conclusion: TyG index was identified as an independent risk factor for HCC development in patients with LC.

2.
RSC Adv ; 14(7): 4456-4460, 2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38312724

ABSTRACT

The generally encountered contradiction between large energy content and stability poses great difficulty in designing nitrogen-rich high-energy-density materials. Although N-N ylide bonds have been classified as the fourth type of homonuclear N-N bonds (besides >N-N<, -N[double bond, length as m-dash]N-, and N[triple bond, length as m-dash]N), accessible energetic molecules with N-N ylide bonds have rarely been explored. In this study, 225 molecules with six types of novel structures containing N-N ylide bonds were designed using density functional theory and CBS-QB3 methods. To guide future synthesis, the effects of substitution on the thermal stability, detonation velocity, and detonation pressure of the structures were evaluated under the premise that the N-N ylide skeleton remains stable. The calculations show that the bond dissociation energy values of the N-N ylide bonds of the designed 225 structures were in the range of 61.21-437.52 kJ mol-1, except for N-1NNH2. Many of the designed structures with N-N ylide bonds exhibit high detonation properties, which are superior to those of traditional energetic compounds. This study convincingly demonstrates the feasibility of the design strategy of introducing an N-N ylide bond to develop new types of energetic materials.

3.
Food Chem ; 440: 138245, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38159320

ABSTRACT

This study aimed to prepare a novel emulsion film with high stability, using soy protein-derived amyloid fibrils (SAFs) as an emulsifier incorporating clove essential oil (CEO) as the active component, and the polyvinyl alcohol (PVA) matrix to stabilize the system. The results demonstrated that SAFs can successfully stabilize CEO. Emulsion prepared by SAFS and CEO (SAC) exhibited a small droplet size and better dispersibility compared with SPI and CEO (SC) emulsion. According to FT-IR results, PVA addition increased the hydrogen bond interactions among emulsion film components, thus further reinforcing the protein matrix, increasing the tensile strength (TS) (41.18 MPa) and elongation at break (E) (121.62 %) of the films. The uniform appearance of SAC-PVA (SACP) emulsion films was confirmed by SEM images. Furthermore, SACP emulsion films show distinctive barrier properties, optical properties, and outstanding antioxidant properties. Finally, emulsion films exhibited excellent preservation of strawberries, resulting in an effective decline of the decay rate.


Subject(s)
Oils, Volatile , Syzygium , Clove Oil/chemistry , Oils, Volatile/chemistry , Soybean Proteins/chemistry , Polyvinyl Alcohol/chemistry , Syzygium/chemistry , Emulsions/chemistry , Amyloid , Spectroscopy, Fourier Transform Infrared , Food Packaging/methods
4.
PeerJ ; 11: e15014, 2023.
Article in English | MEDLINE | ID: mdl-36992940

ABSTRACT

Background: We aimed to evaluate the prediction values of non-invasive models for hepatocellular carcinoma (HCC) development in patients with HBV-related liver cirrhosis (LC) and long-term NA treatment. Methods: Patients with compensated or decompensated cirrhosis (DC), who achieved long-term virological response, were enrolled. DC and its stages were defined by the complications including ascites, encephalopathy, variceal bleeding, or renal failure. Prediction accuracy of several risk scores, including ALBI, CAMD, PAGE-B, mPAGE-B and aMAP, was compared. Results: The median follow-up duration was 37 (28-66) months. Among the 229 patients, 9 (9.57%) patients in the compensated LC group and 39 (28.89%) patients in the DC group developed HCC. The incidence of HCC was higher in the DC group ( X 2 = 12.478, P < 0.01). The AUROC of ALBI, aMAP, CAMD, PAGE-B and mPAGE-B scores were 0.512, 0.667, 0.638, 0.663, 0.679, respectively. There was no significant difference in AUROC between CAMD, aMAP, PAGE-B and mPAGE-B (all P > 0.05). Univariable analysis showed that age, DC status and platelet were associated with HCC development, and multivariable analysis showed that age and DC status (both P < 0.01) were independent risk factors for HCC development, then Model (Age_DC) was developed and its AUROC was 0.718. Another model, Model (Age_DC_PLT_TBil) consisting of age, DC stage, PLT, TBil was also developed, and its AUROC was larger than that of Model (Age_DC) (0.760 vs. 0.718). Moreover, AUROC of Model (Age_DC_PLT_TBil) was larger than the other five models (all P < 0.05). With an optimal cut-off value of 0.236, Model (Age_DC_PLT_TBil) achieved 70.83% sensitivity, 76.24% specificity. Conclusion: There is a lack of non-invasive risk scores for HCC development in HBV-related DC, and a new model consisting of age, DC stage, PLT, TBil may be an alternative.


Subject(s)
Carcinoma, Hepatocellular , Esophageal and Gastric Varices , Liver Neoplasms , Humans , Carcinoma, Hepatocellular/epidemiology , Prospective Studies , Hepatitis B virus , Liver Neoplasms/epidemiology , Esophageal and Gastric Varices/epidemiology , Antiviral Agents/therapeutic use , Gastrointestinal Hemorrhage/complications , Liver Cirrhosis/complications
5.
Article in English | MEDLINE | ID: mdl-36429429

ABSTRACT

Rural settlements are the spatial carriers of rural multifunctionality, and various issues related to livability are the main manifestations and causes of unbalanced and insufficient rural development. In the new era, it is imperative to promote the livability of rural settlements with the implementation of rural revitalization. However, compared with urban settlements, there are still fewer studies on the livability of rural settlements, especially those in disaster-prone areas; thus, this paper takes the upper reaches of the Minjiang River as the study area. It adopts GIS spatial analysis and the model of minimum cumulative resistance, etc., to conduct a livability evaluation and construct an optimization model by innovatively taking five aspects into account including site security and resource endowment. The results show that: (1) The overall livability of the region is relatively good, and the main factors affecting the livability are site security and economic affluence; (2) The location of rural settlements was highly livability-oriented, and the area of rural settlements in the moderate- and high-livability zones accounted for more than 90%; and (3) The key to improving the livability of rural settlements lies in the construction of development synergy, disaster management, cultural preservation and industrial upgrading, and thus, four types of settlement livability enhancement are proposed. The research results provide theoretical support for the construction of livable villages in the upper reaches of the Minjiang River and similar mountainous areas.


Subject(s)
Disasters , Rivers , Humans , China , Rural Population
6.
J Hepatocell Carcinoma ; 9: 1057-1063, 2022.
Article in English | MEDLINE | ID: mdl-36250136

ABSTRACT

Background and Aims: High incidence of hepatocellular carcinoma (HCC) exists in patients with liver cirrhosis (LC), but the predictive accuracy of noninvasive scoring systems (NSSs) is yet to be elucidated. The present study aimed to evaluate the predictive ability of fibrosis-4 (FIB-4), aminotransferase-to-platelet ratio index (APRI), and gamma-glutamyl transpeptidase to platelet ratio (GPR) in patients with LC, and to establish a new model with more accuracy. Methods: Data from 94 patients with compensated LC and 134 patients with decompensated cirrhosis (DC) were collected. The prediction accuracy of NSSs, including APRI, GPR, and FIB-4, was compared. Results: During a median follow-up of 37.5 months, 9 patients in the compensated LC group and 38 in the DC group developed HCC. For 228 patients, the area under the receiver operating characteristic curve (AUROC) of APRI, GPR, and FIB-4 was 0.596, 0.625, and 0.654, respectively. Multivariable logistic analysis showed that age, gamma-glutamyl transpeptidase (GGT), and platelet (PLT) were independent risk factors for HCC development, and a new model encompassing age, GGT, and PLT was superior to NSSs (all P<0.05). With an optimal cutoff value of 0.216, Model (Age_GGT_PLT) achieved 68.09% sensitivity and 69.61% specificity. Conclusion: NSSs, including APRI, GPR, and FIB-4, has a non-optimal accuracy in predicting HCC development in patients with HBV-related LC. Thus, the new model consisting of age, GGT, and PLT may be more accurate than NSSs.

7.
Appl Phys A Mater Sci Process ; 127(8): 588, 2021.
Article in English | MEDLINE | ID: mdl-34276141

ABSTRACT

This study reports the synthesis and characterization of the red nanophosphors Zn2SiO4:Eu3+ (ZSO:Eu3+) and Mg2TiO4:Mn4+ (MTO:Mn4+). The use of phosphors as a fluorescence label for lateral flow immunochromatographic assay (LFIA) has also been described. The optimal photoluminescence (PL) for ZSO:Eu3+ was obtained when it was synthesized with 7 mol% of Eu3+ and annealed at 1100 °C for 1 h. Long fluorescence lifetime (1.01 ms), high activation energy E a (0.28 eV), and low PL degeneration (10% at 110 °C) are the characteristics of ZSO:Eu3+. MTO:Mn4+ also exhibited high PL intensity along with a high E a of 0.32 eV. The emission wavelengths of phosphors are biocompatible with the optical bio-window of tissues. When human immunoglobulin G (human IgG) at a constant concentration of 100 µg/mL was used for detection, the PL ratios of the test line to the control line were 2.15 and 2.28 for the ZSO:Eu3+- and MTO:Mn4+-labeled LFIA, respectively. Thus, the ZSO:Eu3+ and MTO:Mn4+ nanophosphors are capable of human IgG recognition and are the promising candidates as fluorescent labels for on-site rapid optical biodetection. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00339-021-04733-0.

9.
Angew Chem Int Ed Engl ; 56(10): 2725-2729, 2017 03 01.
Article in English | MEDLINE | ID: mdl-28140506

ABSTRACT

A one-pot N-Boc deprotection and catalytic intramolecular reductive amination protocol for the preparation of enantiomerically pure tetrahydroisoquinoline alkaloids is described. The iodine-bridged dimeric iridium complexes displayed superb stereoselectivity to give tetrahydroisoquinolines, including several key pharmaceutical drug intermediates, in excellent yields under mild reaction conditions. Three additives played important roles in this reaction: Titanium(IV) isopropoxide and molecular iodine accelerated the transformation of the intermediate imine to the tetrahydroisoquinoline product; p-toluenesulfonic acid contributed to the stereocontrol.

10.
Electrophoresis ; 31(17): 2949-56, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20690149

ABSTRACT

A novel method was proposed for simultaneous measurement of diffusion coefficients, (D), from mixed samples by electrophoresis and termed electromigration-based diffusivity spectrometry. After theoretical treatment, D-equation for practical use has been deduced. With a modified CE system built in laboratory, electromigration-based diffusivity spectrometry has been realized and validated to suit for fast and accurate determination of diffusivities of mixed aromatic amino acids, phenols and aromatic organic acid, giving diffusivity spectra by peak area versus D, much similar to mass spectra. The precision of the measurement was found to critically depend on pH value of running buffer, which should be so selected that the analytes and internal standards could be charged at above 0.5e. The standards have to be selected at an electric flux far from each other and from analytes. In these cases, sample and running buffer concentrations, voltage and system temperature were found to have only negligible impact on the determination. In our test, the obtained measuring precision was generally kept within 1% for five runs, and the measured values of D agreed well with those from literature, with a deviation of less than 2.2% after the right use of calibration standards.


Subject(s)
Diffusion , Electrophoresis, Capillary/methods , Spectrum Analysis/methods , Algorithms , Dichloroacetic Acid/chemistry , Hydrogen-Ion Concentration , Organic Chemicals/chemistry , Organic Chemicals/isolation & purification , Osmolar Concentration , Pharmaceutical Preparations/chemistry , Pharmaceutical Preparations/isolation & purification , Reproducibility of Results
11.
Vaccine ; 27 Suppl 5: F40-5, 2009 Nov 20.
Article in English | MEDLINE | ID: mdl-19931718

ABSTRACT

Rotavirus was detected in 52% of 2328 stool specimens collected from children with acute gastroenteritis admitted to three sentinel hospitals in Mainland China from January 2006 to December 2007. G3P[8] (42%) was the most common strain. Despite being common globally, only 18 (2%) G9-positive samples were identified. The VP7, VP4, VP6, and NSP4 genes were sequences for 13 of the G9 strains with G9P[8] being most common and showing the same origin as G9 strains reported in other countries. One G9P[6] strain was possibly derived by reassortment between earlier Chinese G9 strains and more recent local P[6] strains.


Subject(s)
Diarrhea/epidemiology , Gastroenteritis/epidemiology , Rotavirus Infections/epidemiology , Rotavirus/genetics , Child, Preschool , China/epidemiology , Diarrhea/virology , Gastroenteritis/virology , Genes, Viral , Genotype , Humans , Infant , Molecular Epidemiology , Prevalence , RNA, Viral/genetics , Sentinel Surveillance , Sequence Analysis, RNA
12.
J Infect Dis ; 200 Suppl 1: S167-73, 2009 Nov 01.
Article in English | MEDLINE | ID: mdl-19817597

ABSTRACT

Rotaviruses cause acute diarrhea worldwide. Previous studies of rotavirus diarrhea in China found that rotavirus infection is the most common cause of severe diarrhea in young children. In the present study, surveillance of rotavirus diarrhea was conducted involving 9549 children aged <5 years who were admitted for treatment of diarrhea at 11 sentinel hospitals in China from August 2003 through July 2007. Group A rotavirus was detected in 3749 (47.8%) of the 7846 fecal specimens by using enzyme-linked immunosorbent assay. Rotavirus isolates were characterized by reverse-transcriptase polymerase chain reaction to determine G and P genotypes. All the strains that are common worldwide were detected; G3P[8] was the most common. An unusual G5 strain was detected in 2 specimens. Of all episodes of rotavirus diarrhea, 94% occurred during the first 2 years of life, peaking at 6-23 months of age. Our findings indicate that globally common rotavirus strains continue to be a major cause of severe childhood diarrhea in China. Introduction of routine immunization with effective rotavirus vaccines would substantially reduce this burden.


Subject(s)
Diarrhea/epidemiology , Rotavirus Infections/epidemiology , Child, Preschool , China/epidemiology , Diarrhea/virology , Feces/virology , Female , Genotype , Hospitalization , Humans , Infant , Infant, Newborn , Male , Rotavirus/classification , Rotavirus Infections/virology , Time Factors
14.
J Clin Virol ; 44(3): 238-41, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19201258

ABSTRACT

BACKGROUND: Gastroenteritis is a major cause of childhood morbidity and mortality worldwide. Rotavirus, human caliciviruses (HucV), adenovirus, and astrovirus are recognized as common etiologies of acute gastroenteritis. OBJECTIVES: To use antigen detection and molecular methods to determine the viral etiology of childhood diarrhea in Lanzhou, China, 2005-2007. STUDY DESIGN: 544 stool specimens were collected from children hospitalized with diarrhea. ELISA, RT-PCR, or PCR were used to detect viruses commonly causing diarrhea. RESULTS: Group A rotavirus, norovirus, sapovirus, astrovirus, and adenovirus, were detected in 54.0%, 9.2%, 1.1%, 3.3%, and 4.4%, respectively. No group B or group C rotaviruses were detected. The relative contribution of these viruses changed greatly over 2 years. The percentage of rotavirus and adenovirus dropped from 61.2% and 5.4% to 47.6% and 1.4%, whereas HucV increased from 5.0% to 15.0%. G1 and P[8] were the predominant rotavirus strains, and P[6] was detected for the first time in this area. The predominant norovirus strain changed from GII3 to GII4, and the subtypes of GII4 changed from the Hunter strain to the variant 2006b strain. CONCLUSIONS: The distribution of viruses and genotypes of individual viruses causing gastroenteritis in Lanzhou, China changed greatly during 2005-2007.


Subject(s)
Diarrhea/virology , Gastroenteritis/virology , Virus Diseases/virology , Viruses/classification , Viruses/isolation & purification , Child, Preschool , China , Enzyme-Linked Immunosorbent Assay/methods , Feces/virology , Genotype , Humans , Infant , Infant, Newborn , Polymerase Chain Reaction/methods , Prevalence , Reverse Transcriptase Polymerase Chain Reaction/methods
15.
J Med Virol ; 80(11): 1997-2004, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18814250

ABSTRACT

Noroviruses are an important cause of acute gastroenteritis. Increasing data showed that the GII-4 strains are predominant worldwide and new GII-4 variants emerge every 1-2 years causing major epidemics. Surveillance of gastroenteritis in hospitalized children under 5 years of age in China is described. Among 1,110 specimens, 114 (10.3%) were positive for noroviruses, which was higher than adenoviruses (7.6%), astroviruses (3.5%), and sapoviruses (0.9%) and only lower than group A rotaviruses (40.6%). Thirty-eight of the 114 positive norovirus cases were co-infected with other enteric viruses. Five norovirus genotypes (GI-2, GI-4, GII-3, GII-4, and GII-14) were detected, with GII-4/2006b the most predominant type (64.9%). The reported recombinant of GII-3 capsid and GII-4 polymerase described previously was also detected frequently and a recombinant of GII-14 capsid and GII-6 polymerase was found for the first time. This study suggests that continual surveillance focusing on strain variation and dynamic change is important for understanding the epidemiology and development of a strategy for disease control and prevention.


Subject(s)
Caliciviridae Infections/epidemiology , Caliciviridae Infections/virology , Gastroenteritis/epidemiology , Gastroenteritis/virology , Norovirus/genetics , Norovirus/isolation & purification , Recombination, Genetic , Child, Preschool , China/epidemiology , Genotype , Humans , Infant , Infant, Newborn , Molecular Epidemiology , Molecular Sequence Data , Phylogeny , RNA, Viral/genetics , Sequence Analysis, DNA , Sequence Homology
16.
J Clin Virol ; 42(3): 280-5, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18499516

ABSTRACT

BACKGROUND: Human bocavirus (HBoV) was first identified in children with acute respiratory-tract infections, but recent studies have revealed that HBoV is also frequently detected in fecal specimens from children with gastroenteritis. OBJECTIVES: To investigate the prevalence of HBoV in children hospitalized with gastroenteritis in different areas of China. STUDY DESIGN: Employing ELISA, RT-PCR or PCR, we evaluated 1216 fecal samples for common diarrheal agents from children aged less than 5-year-old hospitalized with acute gastroenteritis. MEGA software was used to construct phylogenetic trees of the VP1/VP2 partial sequences of the HBoV genome. RESULTS: There were 67 HBoV-positive specimens, 52 (77.6%) were co-infected with rotavirus, norovirus, astrovirus, or enteric adenovirus. Statistical analysis of the clinical data indicated that children infected with both rotavirus and bocavirus did not have more severe clinical symptoms than children infected with rotavirus. The phylogenetic analysis of the VP1/VP2 partial sequences of the HBoV genome revealed a single genetic lineage. CONCLUSIONS: Despite its high infection rate, there was no statistically significant a causual relationship between HBoV and gastroenteritis in children.


Subject(s)
Bocavirus/isolation & purification , Gastroenteritis/epidemiology , Gastroenteritis/virology , Parvoviridae Infections/epidemiology , Parvoviridae Infections/virology , Adenoviridae/isolation & purification , Child, Preschool , China/epidemiology , Comorbidity , Enzyme-Linked Immunosorbent Assay , Feces/virology , Female , Genome, Viral , Hospitalization , Humans , Infant , Infant, Newborn , Male , Molecular Sequence Data , Norovirus/isolation & purification , Phylogeny , Polymerase Chain Reaction , Prevalence , Reverse Transcriptase Polymerase Chain Reaction , Rotavirus/isolation & purification , Sequence Analysis, DNA , Sequence Homology , Viral Structural Proteins/genetics
17.
Nan Fang Yi Ke Da Xue Xue Bao ; 27(12): 1805-8, 2007 Dec.
Article in Chinese | MEDLINE | ID: mdl-18158988

ABSTRACT

OBJECTIVE: This paper describes a new method for extracting and segmenting intracranial structure from serial images of cerebral computerized tomography automatically. A region growing- and morphology-based approach was first developed to extract intracranial structures from the serial images of cerebral computerized tomography, and focusing on the problems of parameter initialization of the expectation maximization (EM) algorithm, an improved EM algorithm based on parameter- limited GMM was presented to segment the intracranial structures successfully. Experimental results of the algorithm showed that this method was effective for all cerebral computerized tomography images from bottom to top of the cerebrum.


Subject(s)
Cerebrum/diagnostic imaging , Pattern Recognition, Automated/methods , Algorithms , Humans , Tomography, X-Ray Computed
18.
Am J Vet Res ; 68(4): 411-22, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17397298

ABSTRACT

OBJECTIVE: To investigate the antitumor effect of the chicken anemia virus (CAV) VP3 gene in canine mammary tumor (CMT) cells. SAMPLE POPULATIONS: Established primary canine cell lines that originated from epithelial cells of resected CMTs and nonneoplastic mammary gland epithelial (MGE) cells. PROCEDURES: Expression vectors and lentiviral vectors encoding the VP3 gene from a Taiwan-Ilan isolate of CAV were used to deliver the VP3 gene into CMT cells and nonneoplastic MGE cells. Ectopic gene expression and the pro-apoptotic effect of the VP3 gene on CMT and nonneoplastic MGE cells by either transfection or viral infection were evaluated via immunofluorescence microscopy, western blot analysis, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling analysis. RESULTS: Overexpression of the enhanced green fluorescent protein-VP3 fusion protein was detected predominantly in the nuclei of CMT cells. In contrast, the VP3 protein was localized to the cytoplasm of nonneoplastic MGE cells. Among the fusion protein-expressing CMT cells, most underwent characteristic changes of apoptosis, whereas apoptosis was not detected in fusion protein-expressing, nonneoplastic MGE cells. Induction of apoptosis by VP3 gene overexpression in CMT cells was associated with the caspase-9-, but not the caspase-8-, mediated apoptosis pathway. CONCLUSIONS AND CLINICAL RELEVANCE: These data indicate that the VP3 gene of the CAV induces apoptosis in malignant CMT cells, but not in nonneoplastic canine MGE cells. On the basis of such tumor cell-specific killing, the VP3 gene may be a promising agent for the treatment of malignant mammary gland tumors in dogs.


Subject(s)
Apoptosis/drug effects , Capsid Proteins/therapeutic use , Chicken anemia virus/genetics , Dog Diseases/therapy , Gene Expression Regulation, Neoplastic/drug effects , Genetic Therapy/methods , Mammary Neoplasms, Animal/therapy , Animals , Blotting, Western/veterinary , Capsid Proteins/pharmacology , Cell Line, Tumor , Dogs , Genetic Vectors , In Situ Nick-End Labeling/veterinary , Lentivirus , Microscopy, Fluorescence/veterinary
19.
Virus Res ; 125(1): 14-28, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17204346

ABSTRACT

Replication of genomic DNAs of plant-pathogenic begomoviruses has been demonstrated in prokaryotes, which supported the possibility of analyzing DNA replication process of begomoviruses in bacteria. However, previous studies indicated that the replication of begomovirus DNAs in prokaryotes requires tandem constructs of viral genomes with at least two copies of the origin of replication (ori). In this study, phage M13 vector harboring the unit-length genome with only a single copy of ori of a mono-partite begomovirus, Ageratum yellow vein virus PD isolate (AYVV-[PD]), was constructed and used to investigate the replication of AYVV-[PD] DNAs in Escherichia coli. The generation of single-stranded, circular DNAs (sscDNAs) corresponding to the unit-length AYVV-[PD] genome of both polarity was observed and verified. Replication-associated (Rep) protein of AYVV-[PD] was detected only in bacteria generating the corresponding sscDNAs, whereas disruption of the Rep gene abolished the phenomenon. The results suggested that a single copy of ori is sufficient for the prokaryotes to support the generation of unit-length, genomic sscDNAs of begomoviruses, which requires the presence of functional Rep protein.


Subject(s)
Begomovirus/genetics , DNA, Circular/metabolism , DNA, Viral/metabolism , Escherichia coli/genetics , Genome, Viral , Plasmids/genetics , Bacteriophage M13/genetics , Coliphages/genetics , DNA, Circular/genetics , DNA, Single-Stranded , DNA, Viral/genetics , Escherichia coli/virology , Genetic Engineering/methods , Replication Origin
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