OBJECTIVETo confirm that arsenic (As) induces oxidative DNA damage in phytohemagglutinin (PHA)-stimulated and unstimulated human lymphocytes.

METHODSThe alkaline comet assay combined with specific enzyme (Formamidopyrimidine-DNA glycosylase, FPG) digestion was used to measure As-induced base damage.

RESULTSThe enzyme-sensitive sites were readily detected with the alkaline comet assay after the cells were treated with 10 micromol As for 2 hours. The repair patterns observed for FPG-created DNA single strand breaks (SSBs) in As-treated cells were comparable to those in hydrogen peroxide (H(2)O(2))-treated cells. The enzyme-created SSBs, As-induced base damage, were more significantly revealed in PHA-stimulated lymphocytes. About 63% and 68% of SSBs induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes by 2-hour repair incubation, but about 34% and 43%, respectively, were repaired in unstimulated cells. About 40% and 49% of base damage induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes, but about 19% and 21 %, respectively, were repaired in unstimulated cells.

CONCLUSIONSAs induces oxidative DNA damage in human lymphocytes within micromolar concentrations. Like the damage induced by H(2)O(2), As-induced DNA damage was more slowly repaired in unstimulated lymphocytes.

Adult ; Arsenic ; pharmacology ; DNA Damage ; DNA Repair ; DNA, Single-Stranded ; drug effects ; DNA-Formamidopyrimidine Glycosylase ; Electrophoresis ; methods ; Humans ; Hydrogen Peroxide ; pharmacology ; Lymphocytes ; drug effects ; N-Glycosyl Hydrolases ; Oxidation-Reduction ; Phytohemagglutinins ; pharmacology

BACKGROUNDGinsenoside Rd (GSRd), one of the main active ingredients in traditional Chinese herbal Panax ginseng, has been found to have therapeutic effects on ischemic stroke. However, the molecular mechanisms of GSRd's neuroprotective function remain unclear. Ischemic stroke-induced oxidative stress results in DNA damage, which triggers cell death and contributes to poor prognosis. Oxidative DNA damage is primarily processed by the base excision repair (BER) pathway. Three of the five major DNA glycosylases that initiate the BER pathway in the event of DNA damage from oxidation are the endonuclease VIII-like (NEIL) proteins. This study aimed to investigate the effect of GSRd on the expression of DNA glycosylases NEILs in a rat model of focal cerebral ischemia.

METHODSNEIL expression patterns were evaluated by quantitative real-time polymerase chain reaction in both normal and middle cerebral artery occlusion (MCAO) rat models. Survival rate and Zea-Longa neurological scores were used to assess the effect of GSRd administration on MCAO rats. Mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) damages were evaluated by the way of real-time analysis of mutation frequency. NEIL expressions were measured in both messenger RNA (mRNA) and protein levels by quantitative polymerase chain reaction and Western blotting analysis. Apoptosis level was quantitated by the expression of cleaved caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling assay.

RESULTSWe found that GSRd administration reduced mtDNA and nDNA damages, which contributed to an improvement in survival rate and neurological function; significantly up-regulated NEIL1 and NEIL3 expressions in both mRNA and protein levels of MCAO rats; and reduced cell apoptosis and the expression of cleaved caspase-3 in rats at 7 days after MCAO.

CONCLUSIONSOur results indicated that the neuroprotective function of GSRd for acute ischemic stroke might be partially explained by the up-regulation of NEIL1 and NEIL3 expressions.

Animals ; Blotting, Western ; Brain Ischemia ; drug therapy ; enzymology ; DNA Damage ; drug effects ; DNA Glycosylases ; genetics ; metabolism ; Ginsenosides ; therapeutic use ; Infarction, Middle Cerebral Artery ; drug therapy ; enzymology ; Male ; N-Glycosyl Hydrolases ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

This study was conducted to investigate the presence of Escherichia (E.) coli O157 and E. coli O157:H7 and stx1 and stx2 genes on cattle carcasses and in rectal samples collected from Samsun Province of Turkey. A total of 200 samples collected from cattle carcasses and the rectal contents of 100 slaughtered cattle from two commercial abattoirs were tested using the immunomagnetic separation technique and multiplex PCR methods. E. coli O157 and E. coli O157:H7 were detected in 52 of the 200 samples (26%) tested. Of the positive samples, 49 were E. coli O157 and three were E. coli O157:H7. The E. coli O157 strain was isolated from 24 carcasses and 25 rectal samples, while E. coli O157:H7 was isolated from two carcasses and one rectal sample. Of the 49 samples positive for E. coli O157, 32 were from the rectal and carcass samples of the same animal, while two E. coli O157:H7 isolates were obtained from rectal swabs and carcasses of the same animal. The stx1 and stx2 genes were both detected in 35 E. coli O157 isolates and one E. coli O157:H7 isolate, but the stx2 gene was only detected alone in two E. coli O157 isolates. Overall, 16 carcasses tested positive for E. coli O157 and one carcass tested positive for E. coli O157:H7 based on both carcass and rectal samples. Overall, the results of this study indicate that cattle carcasses pose a potential risk to human health due to contamination by E. coli O157 and E. coli O157:H7 in the feces.
Abattoirs ; Animals ; Cattle ; Escherichia coli O157/*genetics/isolation & purification ; *Immunomagnetic Separation ; Meat/microbiology ; *Polymerase Chain Reaction ; Rectum/microbiology ; Shiga Toxin 1/*genetics ; Shiga Toxin 2/*genetics ; Turkey

China ; epidemiology ; Escherichia coli Infections ; epidemiology ; microbiology ; Escherichia coli O157 ; classification ; isolation & purification ; metabolism ; Humans ; Shiga Toxin 1 ; biosynthesis ; isolation & purification ; Shiga Toxin 2 ; biosynthesis ; isolation & purification ; Sorbitol

Eight saporin peaks were obtained from the purification of seed extracts of Saponaria officinalis L. Saporin peak No. 6 (SAP-6) showed the highest activity in the inhibition of protein synthesis (98%) in an in vitro translation study. An immunotoxin (IT) was prepared from SAP-6 conjugated to a monoclonal anti-CEA antibody 26/5/1 (mab B) using N-succinimidyl pyridyl dithiopropionate (SPDP) and 2-iminothiolane as a cross linker. Under thermal stability study by a DSC (differential scanning calorimetry), the IT showed a denature temperature of 75 degrees C. In in vitro translation studies, the purified IT showed the same activity as SAP-6 at 10(-7) M and 10(-9) M protein concentration at 0, 30 and 60-min incubation effects with mab B and SAP-6 not conjugated at 24-hr incubation periods on human promyelocytic cell line HL 60 and on human colon adenocarcinoma cell lines which were SW 403, LoVo and LS 174 T. SAP-6, mab B and IT had no cytotoxic effect on HL-60. The IT showed a higher cytotoxic effect than SAP-6 in CEA-positive cell lines. The IT demonstrated the highest cytotoxic effect of 51% inhibition of control at 10(-7) M on the LS 174 T.
Antibodies, Monoclonal/*therapeutic use ; Antineoplastic Agents, Phytogenic/administration & dosage/*pharmacology ; Carcinoembryonic Antigen/biosynthesis/*immunology ; Colonic Neoplasms/*pathology/therapy ; Hot Temperature ; Humans ; Immunotoxins/*therapeutic use ; *N-Glycosyl Hydrolases ; Plant Proteins/administration & dosage/*pharmacology ; Ribosome Inactivating Proteins, Type 1 ; Tumor Cells, Cultured/drug effects

We evaluated the effect of the conjugate of basic fibroblast growth factor (FGF2) and saporin (FGF2-SAP) on proliferation of cultured keratocytes. Cultured rabbit and human keratocytes were incubated in medium containing 0.01 to 100 nM of chemical conjugate of EGF2 conjugated by disulfide bond to saporin (CCFS1), FGF2 genetically fused to saporin (rFGF2-SAP), FGF2, or saporin for three hours or four days and cell proliferation was quantified four days after the drug treatment. Proliferation of rabbit and human keratocytes was effectively inhibited by three hour and by four day exposure to CCFS1 and rFGF2-SAP in a dose-dependent manner, whereas it was affected minimally by four day exposure to saporin. Their inhibitory effects were detected at concentrations above 0.1 or 1 nM, and were most prominent in serum-stimulated rabbit keratocytes. These results suggest a potential role for FGF2-SAP in limiting proliferation of keratocytes during corneal wound healing.
Animals ; Antineoplastic Agents, Phytogenic/*pharmacology ; Cell Division/drug effects ; Cell Line ; Cells, Cultured ; Corneal Stroma/*cytology/drug effects ; Dose-Response Relationship, Drug ; Fibroblast Growth Factor 2/*pharmacology ; Humans ; Immunotoxins/pharmacology ; *N-Glycosyl Hydrolases ; Plant Proteins/*pharmacology ; Rabbits ; Ribosome Inactivating Proteins, Type 1

A multiplex loop-mediated isothermal amplification (mLAMP) assay was developed for simultaneous detection of the stx1 and stx2 genes and applied for detection of shiga toxin-producing Escherichia coli (STEC) in cattle farm samples. Two target genes were distinguished based on T m values of 85.03 +/- 0.54degrees C for stx1 and 87.47 +/- 0.35degrees C for stx2. The mLAMP assay was specific (100% inclusivity and exclusivity), sensitive (with a detection limit as low as 10 fg/microL), and quantifiable (R 2 = 0.9313). The efficacy and sensitivity were measured to evaluate applicability of the mLAMP assay to cattle farm samples. A total of 12 (12/253; 4.7%) and 17 (17/253; 6.7%) STEC O157, and 11 (11/236; 4.7%) non-O157 STEC strains were isolated from cattle farm samples by conventional selective culture, immunomagnetic separation, and PCR-based culture methods, respectively. The coinciding multiplex PCR and mLAMP results for the types of shiga toxin revealed the value of the mLAMP assay in terms of accuracy and rapidity for characterizing shiga toxin genes. Furthermore, the high detection rate of specific genes from enrichment broth samples indicates the potential utility of this assay as a screening method for detecting STEC in cattle farm samples.
Animals ; Cattle ; Cattle Diseases/epidemiology/microbiology ; Escherichia coli Infections/epidemiology/microbiology/*veterinary ; Feces/microbiology ; Multiplex Polymerase Chain Reaction/veterinary ; Nucleic Acid Amplification Techniques/*veterinary ; Shiga Toxin 1/*genetics/isolation & purification ; Shiga Toxin 2/*genetics/isolation & purification ; Shiga-Toxigenic Escherichia coli/*genetics/isolation & purification

A total of 156 Shiga-like toxin producing Escherichia coli (STEC) were isolated from fecal samples of Korean native (100/568, 18%) and Holstein dairy cattle (56/524, 11%) in Korea between September 2010 and July 2011. Fifty-two STEC isolates (33%) harbored both of shiga toxin1 (stx1) and shiga toxin2 (stx2) genes encoding enterohemolysin (EhxA) and autoagglutinating adhesion (Saa) were detected by PCR in 83 (53%) and 65 (42%) isolates, respectively. By serotyping, six STEC from native cattle and four STEC from dairy cattle were identified as O-serotypes (O26, O111, O104, and O157) that can cause human disease. Multilocus sequence typing and pulsed-field gel electrophoresis patterns highlighted the genetic diversity of the STEC strains and difference between strains collected during different years. Antimicrobial susceptibility tests showed that the multidrug resistance rate increased from 12% in 2010 to 42% in 2011. Differences between isolates collected in 2010 and 2011 may have resulted from seasonal variations or large-scale slaughtering in Korea performed to control a foot and mouth disease outbreak that occurred in early 2011. However, continuous epidemiologic studies will be needed to understand mechanisms. More public health efforts are required to minimize STEC infection transmitted via dairy products and the prevalence of these bacteria in dairy cattle.
Animals ; Anti-Bacterial Agents/pharmacology ; Cattle/microbiology ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field/veterinary ; Escherichia coli Infections/epidemiology/microbiology/*veterinary ; Female ; Genes, Bacterial/genetics ; Latex Fixation Tests/veterinary ; Microbial Sensitivity Tests/veterinary ; Multilocus Sequence Typing/veterinary ; Prevalence ; Republic of Korea/epidemiology ; Shiga Toxin 1/genetics ; Shiga Toxin 2/genetics ; *Shiga-Toxigenic Escherichia coli/drug effects/genetics

Escherichia (E.) coli serotype O157:H7 is a globally distributed human enteropathogen and is comprised of microorganisms with closely related genotypes. The main reservoir for this group is bovine bowels, and infection mainly occurs after ingestion of contaminated water and food. Virulence genetic markers of 28 O157:H7 strains were investigated and multilocus enzyme electrophoresis (MLEE) was used to evaluate the clonal structure. O157:H7 strains from several countries were isolated from food, human and bovine feces. According to MLEE, O157:H7 strains clustered into two main clonal groups designated A and B. Subcluster A1 included 82% of the O157:H7 strains exhibiting identical MLEE pattern. Most enterohemorrhagic E. coli (EHEC) O157:H7 strains from Brazil and Argentina were in the same MLEE subgroup. Bovine and food strains carried virulence genes associated with EHEC pathogenicity in humans.
Animals ; Argentina/epidemiology ; Brazil/epidemiology ; Cattle ; Cattle Diseases/epidemiology/*microbiology ; Enterohemorrhagic Escherichia coli/genetics/*isolation & purification/pathogenicity ; Escherichia coli O157/*genetics/*isolation & purification/pathogenicity ; Food Microbiology ; Gene Expression Regulation, Bacterial/physiology ; Genetic Markers ; Humans ; Polymerase Chain Reaction/veterinary ; Shiga Toxin 1/genetics/metabolism ; Shiga Toxin 2/genetics/metabolism ; Virulence

Adenosine diphosphate (ADP)-ribosylation is a unique post-translational modification that regulates many biological processes, such as DNA damage repair. During DNA repair, ADP-ribosylation needs to be reversed by ADP-ribosylhydrolases. A group of ADP-ribosylhydrolases have a catalytic domain, namely the macrodomain, which is conserved in evolution from prokaryotes to humans. Not all macrodomains remove ADP-ribosylation. One set of macrodomains loses enzymatic activity and only binds to ADP-ribose (ADPR). Here, we summarize the biological functions of these macrodomains in DNA damage repair and compare the structure of enzymatically active and inactive macrodomains. Moreover, small molecular inhibitors have been developed that target macrodomains to suppress DNA damage repair and tumor growth. Macrodomain proteins are also expressed in pathogens, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, these domains may not be directly involved in DNA damage repair in the hosts or pathogens. Instead, they play key roles in pathogen replication. Thus, by targeting macrodomains it may be possible to treat pathogen-induced diseases, such as coronavirus disease 2019 (COVID-19).
ADP-Ribosylation ; COVID-19/metabolism* ; DNA Repair/physiology* ; Evolution, Molecular ; Humans ; Models, Biological ; Models, Molecular ; N-Glycosyl Hydrolases/metabolism* ; Poly(ADP-ribose) Polymerases/metabolism* ; Protein Domains ; SARS-CoV-2/pathogenicity*