AIM: To present an approach for selectively killing retrovirus-infected cells that combines the toxicity of Pseudomonas exotoxin (PE) and the presence of reverse transcriptase (RT) in infected cells. METHODS: PE antis...AIM: To present an approach for selectively killing retrovirus-infected cells that combines the toxicity of Pseudomonas exotoxin (PE) and the presence of reverse transcriptase (RT) in infected cells. METHODS: PE antisense toxin RNA has palindromic stem loops at its 5' and 3' ends enabling self-primed generation of cDNA in the presence of RT. The RT activity expressed in retrovirus-infected cells converts "antisense-toxin-RNA" into a lethal toxin gene exclusively in these cells. RESULTS: Using cotransfection studies with PE-expressing RNAs and β-gal expressing reporter plasmids, we show that, in HepG2 and HepG2.2.15 hepatoma cells as well as in duck hepatitis B virus (DHBV) infected cells, HBV or DHBV-polymerase reverse transcribe a lethal cDNA copy of an antisense toxin RNA, which is composed of sequences complementary to a PE gene and eukaryotic transcription and translation signals. CONCLUSION: This finding may have important implications as a novel therapeutic strategy aimed at the elimination of HBV infection.展开更多
Clostridium peringens, also called clostridium westergren, mainly causes diseases in ruminants, such as gas gangrene, enterotoxaemia, hemorrhagic enteritis of cattle and sheep. The bacteria are divided into five subty...Clostridium peringens, also called clostridium westergren, mainly causes diseases in ruminants, such as gas gangrene, enterotoxaemia, hemorrhagic enteritis of cattle and sheep. The bacteria are divided into five subtypes including A, B, C, D and E subtype, which can secrete more than 10 kinds of exotoxin,In these toxins, a, β, ε and ζ play a key pathogenic role. At present, the disease is prevented mainly by univalent vaccine, combined vaccine and muhivalent inactivated vaccine. And the genetic engineering subunit vaccine and nucleic acid vaccine has wide develop- ment prospects. In order to provide some reference for comprehensive prevention and deep research of C. pe^ringens, the etiological characteristics of C. perfrin- germ, pathogenic mechanism of exotoxin and research progress of related vaccines were reviewed, and the genetic engineering subunit vaccine and nucleic acid vac- cine development prospects were also discussed in this paper.展开更多
Background: Streptococcus pyogenes (group A streptococcus, GAS) is an important human bacterial pathogen. This organism possesses many virulence factors, Streptococcal pyrogenic exotoxinone of these. Aim: Detection of...Background: Streptococcus pyogenes (group A streptococcus, GAS) is an important human bacterial pathogen. This organism possesses many virulence factors, Streptococcal pyrogenic exotoxinone of these. Aim: Detection of Streptococcal pyrogenic exotoxin SpeA and SpeB in isolated Streptococcus pyogenes. Methods: Tow hundred throat swab samples were collected from children with pharyngitis referred to Pediatric Teaching hospital and ENT hospital Wad medani, Sudan, from January to November 2021. The questionnaire was filled out to collect clinical and demographic data. Throat swabs were collected and processed with the standard microbiological procedure to isolate Streptococcus pyogenes. Antimicrobial susceptibility testing was done on all GAS isolates using the Kirby Bauer disk diffusion method according to clinical laboratory standard institute (CLSI) guidelines. Detection of Spy 1258 gene and Streptococcal pyrogenic exotoxins SpeA and SpeB were done by using Multiplex PCR. Results: Amongst the Tow hundred collected samples fifty-one isolates (25.5%) were identified as S. pyogenes. Antibiotic susceptibility testing showed that all the GAS isolates were sensitive to Azithromycin and Penicillin. Sensitivity to Erythromycin, Gentamicin, Clarithromycin, Amoxicillin and Cephalexin were 88.2%, 86.3%, 45.1%, 41.2%, 13.7%, respectively. SpeA was detected in 17 (33.3%) and SpeB in 48 (94.1%). Conclusion: Streptococcal pyrogenic exotoxin genes SpeA and SpeB were detected in 17 (33.3%) and 48 (94.1%) respectively of Streptococcus pyogenes isolates.展开更多
A biosensor featuring an S-tapered fiber(STF) with a composite bio-sensitive film comprising graphene oxide and gold nanoparticles, has been proposed for the rapid, highly sensitive, and label-free detection of pseudo...A biosensor featuring an S-tapered fiber(STF) with a composite bio-sensitive film comprising graphene oxide and gold nanoparticles, has been proposed for the rapid, highly sensitive, and label-free detection of pseudomonas exotoxin(PE).The STF was created using a fusion splicer. Subsequently, the composite film and nanobody were successively assembled onto its surface. The detection mechanism relies on monitoring changes in the external refractive index induced by the specific binding of PE to the nanobody. The developed STF biosensor exhibited a remarkable sensitivity of 0.28 nm/(ng/mL)and a limit of detection as low as 0.21 ng/mL for PE.展开更多
Botulinum toxin,a protein exotoxin secreted by Clostridium botulinum,binds to peripheral nerve terminals,inhibits acetylcholine release,and leads to flaccid muscle paralysis.[1]Botox(onabotulinum toxin A)was approved ...Botulinum toxin,a protein exotoxin secreted by Clostridium botulinum,binds to peripheral nerve terminals,inhibits acetylcholine release,and leads to flaccid muscle paralysis.[1]Botox(onabotulinum toxin A)was approved by the Food and Drug Administration(FDA)for cosmetic and therapeutic indications in 2002,and its global use has increased substantially.[2]However,some unlicensed botulinum toxin products may cause iatrogenic botulism.[3]Early diagnosis remains challenging owing to non-specific clinical features and the lack of diagnostic biomarkers,often delaying the timely administration of antitoxin.[4]This study reviewed recent cases of botulism in our center and summarized their clinical presentations,symptoms,and outcomes.展开更多
Bioassay of 51 strains of Bacillus thuringiensis to Bursaphelenchus xylophilus had been studied in laboratory. Two of them had higher toxicity to B. xylophilus. Extraction of endotoxin and exotoxin of the two isolates...Bioassay of 51 strains of Bacillus thuringiensis to Bursaphelenchus xylophilus had been studied in laboratory. Two of them had higher toxicity to B. xylophilus. Extraction of endotoxin and exotoxin of the two isolates to B. xylophilus showed the action of exotoxin higher than that of endotoxin.展开更多
文摘AIM: To present an approach for selectively killing retrovirus-infected cells that combines the toxicity of Pseudomonas exotoxin (PE) and the presence of reverse transcriptase (RT) in infected cells. METHODS: PE antisense toxin RNA has palindromic stem loops at its 5' and 3' ends enabling self-primed generation of cDNA in the presence of RT. The RT activity expressed in retrovirus-infected cells converts "antisense-toxin-RNA" into a lethal toxin gene exclusively in these cells. RESULTS: Using cotransfection studies with PE-expressing RNAs and β-gal expressing reporter plasmids, we show that, in HepG2 and HepG2.2.15 hepatoma cells as well as in duck hepatitis B virus (DHBV) infected cells, HBV or DHBV-polymerase reverse transcribe a lethal cDNA copy of an antisense toxin RNA, which is composed of sequences complementary to a PE gene and eukaryotic transcription and translation signals. CONCLUSION: This finding may have important implications as a novel therapeutic strategy aimed at the elimination of HBV infection.
基金Supported by Monitoring and Control Program of Animal Diseases of the Ministry of Agriculture
文摘Clostridium peringens, also called clostridium westergren, mainly causes diseases in ruminants, such as gas gangrene, enterotoxaemia, hemorrhagic enteritis of cattle and sheep. The bacteria are divided into five subtypes including A, B, C, D and E subtype, which can secrete more than 10 kinds of exotoxin,In these toxins, a, β, ε and ζ play a key pathogenic role. At present, the disease is prevented mainly by univalent vaccine, combined vaccine and muhivalent inactivated vaccine. And the genetic engineering subunit vaccine and nucleic acid vaccine has wide develop- ment prospects. In order to provide some reference for comprehensive prevention and deep research of C. pe^ringens, the etiological characteristics of C. perfrin- germ, pathogenic mechanism of exotoxin and research progress of related vaccines were reviewed, and the genetic engineering subunit vaccine and nucleic acid vac- cine development prospects were also discussed in this paper.
文摘Background: Streptococcus pyogenes (group A streptococcus, GAS) is an important human bacterial pathogen. This organism possesses many virulence factors, Streptococcal pyrogenic exotoxinone of these. Aim: Detection of Streptococcal pyrogenic exotoxin SpeA and SpeB in isolated Streptococcus pyogenes. Methods: Tow hundred throat swab samples were collected from children with pharyngitis referred to Pediatric Teaching hospital and ENT hospital Wad medani, Sudan, from January to November 2021. The questionnaire was filled out to collect clinical and demographic data. Throat swabs were collected and processed with the standard microbiological procedure to isolate Streptococcus pyogenes. Antimicrobial susceptibility testing was done on all GAS isolates using the Kirby Bauer disk diffusion method according to clinical laboratory standard institute (CLSI) guidelines. Detection of Spy 1258 gene and Streptococcal pyrogenic exotoxins SpeA and SpeB were done by using Multiplex PCR. Results: Amongst the Tow hundred collected samples fifty-one isolates (25.5%) were identified as S. pyogenes. Antibiotic susceptibility testing showed that all the GAS isolates were sensitive to Azithromycin and Penicillin. Sensitivity to Erythromycin, Gentamicin, Clarithromycin, Amoxicillin and Cephalexin were 88.2%, 86.3%, 45.1%, 41.2%, 13.7%, respectively. SpeA was detected in 17 (33.3%) and SpeB in 48 (94.1%). Conclusion: Streptococcal pyrogenic exotoxin genes SpeA and SpeB were detected in 17 (33.3%) and 48 (94.1%) respectively of Streptococcus pyogenes isolates.
基金supported by the National Natural Science Foundation of China (Nos.91860140,62090064,and U19A2077)。
文摘A biosensor featuring an S-tapered fiber(STF) with a composite bio-sensitive film comprising graphene oxide and gold nanoparticles, has been proposed for the rapid, highly sensitive, and label-free detection of pseudomonas exotoxin(PE).The STF was created using a fusion splicer. Subsequently, the composite film and nanobody were successively assembled onto its surface. The detection mechanism relies on monitoring changes in the external refractive index induced by the specific binding of PE to the nanobody. The developed STF biosensor exhibited a remarkable sensitivity of 0.28 nm/(ng/mL)and a limit of detection as low as 0.21 ng/mL for PE.
文摘Botulinum toxin,a protein exotoxin secreted by Clostridium botulinum,binds to peripheral nerve terminals,inhibits acetylcholine release,and leads to flaccid muscle paralysis.[1]Botox(onabotulinum toxin A)was approved by the Food and Drug Administration(FDA)for cosmetic and therapeutic indications in 2002,and its global use has increased substantially.[2]However,some unlicensed botulinum toxin products may cause iatrogenic botulism.[3]Early diagnosis remains challenging owing to non-specific clinical features and the lack of diagnostic biomarkers,often delaying the timely administration of antitoxin.[4]This study reviewed recent cases of botulism in our center and summarized their clinical presentations,symptoms,and outcomes.
文摘Bioassay of 51 strains of Bacillus thuringiensis to Bursaphelenchus xylophilus had been studied in laboratory. Two of them had higher toxicity to B. xylophilus. Extraction of endotoxin and exotoxin of the two isolates to B. xylophilus showed the action of exotoxin higher than that of endotoxin.
