The aim of this study is to express the receptor-binding domain of Bacillus anthracis protective antigen in E.coli . Signal sequence of the outer membrane protein A (OmpA) of E.coli was attached to the 5′ end of the ...The aim of this study is to express the receptor-binding domain of Bacillus anthracis protective antigen in E.coli . Signal sequence of the outer membrane protein A (OmpA) of E.coli was attached to the 5′ end of the gene encoding protective antigen receptor-binding domain (the 4 th domain of PA, PAD4). The plasmid carrying the fusion gene was then transformed into E.coli and induced to express recombinant PAD4 by IPTG. The recombinant protein was purified by chromatography and then identified by N-terminal sequencing and Western blot. The recombinant protein, about 10% of the total bacterial protein in volume, was secreted to the periplasmic space of the cell. After a purification procedure including ion-exchange chromatography and gel filtration, about 10 mg of homogenous recombinant PAD4 was obtained from 1 L culture. Data from N-terminal sequencing suggested that the amino acid sequence of recombinant PAD4 was identical with its natural counterpart. And the result of Western blot showed the recombinant protein could bind with anti-PA serum from rabbit. High level secreted expression of PAD4 was obtained in E.coli . The results reported here are parts of a continuing research to evaluate PAD4 as a potential drug for anthrax therapy or a candidate of new vaccine.展开更多
Background Anthrax,a zoonotic disease caused by the spore-forming bacterium Bacillus anthracis,remains a major global public health concern,especially in countries with limited resources.Sierra Leone,a West African co...Background Anthrax,a zoonotic disease caused by the spore-forming bacterium Bacillus anthracis,remains a major global public health concern,especially in countries with limited resources.Sierra Leone,a West African country historically plagued by anthrax,has almost been out of report on this disease in recent decades.In this study,we described a large-scale anthrax outbreak affecting both animals and humans and attempted to characterize the path-ogenusingmoleculartechniques.Methods The causative agent of the animal outbreak in Port Loko District,Sierra Leone,between March and May 2022 was identified using the nanopore sequencing technique.A nationwide active surveillance was implemented from May 2022 to June 2023 to monitor the occurrence of anthrax-specific symptoms in humans.Suspected cases were subsequently verified using quantitative polymerase chain reaction.Full-genome sequencing was accomplished by combining long-read and short-read sequencing methods.Subsequent phylogenetic analysis was performed based on the full-chromosome single nucleotide polymorphisms.Results The outbreak in Port Loko District,Sierra Leone,led to the death of 233 animals between March 26th and May 16th,2022.We ruled out the initial suspicion of Anaplasma species and successfully identified B.anthracis as the causative agent of the outbreak.As a result of the government's prompt response,out of the 49 suspected human cases identifed during the one-year active surveillance,only 6 human cases tested positive,all within the frst month after the official declaration of the outbreak.The phylogenetic analysis indicated that the BaSL2022 isolate responsible for the outbreak was positioned in the A.Br.153 clade within the TransEuroAsian group of B.anthracis.Conclusions We successfully identifed a large-scale anthrax outbreak in Sierra Leone.The causative isolate of B.anthracis,BaSL2022,phylogenetically bridged other lineages in A.Br.153 clade and neighboring genetic groups,A.Br.144 and A.Br.148,eventually confirming the spillover of anthrax from West Africa.Given the wide dissemination of B.anthracis spores,it is highly advisable to effectively monitor the potential reoccurrence of anthrax outbreaks and to launch campaigns to improve public awareness regarding anthrax in Sierra Leone.展开更多
Multi-walled carbon nanotube（MWCNT） sheet was fabricated from a drawable MWCNT forest and then deposited on poly（methyl methacrylate） film. The film was further coated with a natural antimicrobial peptide nisin. W...Multi-walled carbon nanotube（MWCNT） sheet was fabricated from a drawable MWCNT forest and then deposited on poly（methyl methacrylate） film. The film was further coated with a natural antimicrobial peptide nisin. We studied the effects of nisin coating on the attachment of Bacillus anthracis spores, the germination of attached spores, and the subsequent biofilm formation from attached spores. It was found that the strong adsorptivity and the super hydrophobicity of MWCNTs provided an ideal platform for nisin coating. Nisin coating on MWCNT sheets decreased surface hydrophobicity, reduced spore attachment, and reduced the germination of attached spores by 3.5 fold, and further inhibited the subsequent biofilm formation by 94.6% compared to that on uncoated MWCNT sheet. Nisin also changed the morphology of vegetative cells in the formed biofilm.The results of this study demonstrated that the anti-adhesion and antimicrobial effect of nisin in combination with the physical properties of carbon nanotubes had the potential in producing effective anti-biofilm formation surfaces.展开更多
In this review, we advance a new concept in developing vaccines and/or drugs to target speci?c proteins expressed during the early stage of Bacillus anthracis (an- thrax) infection and address existing challenges to t...In this review, we advance a new concept in developing vaccines and/or drugs to target speci?c proteins expressed during the early stage of Bacillus anthracis (an- thrax) infection and address existing challenges to this concept. Three proteins (immune inhibitor A, GPR-like spore protease, and alanine racemase) initially identi?ed by proteomics in our laboratory were found to have di?erential expres- sions during anthrax spore germination and early outgrowth. Other studies of di?erent bacillus strains indicate that these three proteins are involved in either germination or cytotoxicity of spores, suggesting that they may serve as potential targets for the design of anti-anthrax vaccines and drugs.展开更多
Anthrax which is caused by Bacillus anthracis is typically a disease of herbivores. Spores existing in the skin, meat, hair or mouth and nose of animals are transmitted to humans through contact with a break in the sk...Anthrax which is caused by Bacillus anthracis is typically a disease of herbivores. Spores existing in the skin, meat, hair or mouth and nose of animals are transmitted to humans through contact with a break in the skin, consumption of infected meat or inhalation of spores [1]. Infected uncooked or insufficiently cooked meats cause oropharyngeal and gastrointestinal system (GIS) anthrax. When this infected materials swallowed anthrax spores may cause lesions from the oral cavity to the caecum. The diagnosis of gastrointestinal system (GIS) anthrax is difficult due to insidious clinical progression of the disease and difficulty in the isolation of agent pathogen. Releated symptoms of GIS anthrax are sore throat, neck swelling, diffuculty swallowing, stomach pain, anoreksia, bloody diarrhea, nause, bloody vomiting and fever. Supportive and antibiotic treatments are required. Benzylpenicillin, rifampicin, clindamycin, chloramphenicol, imipenem/cilastatin, or vancomycin can be use for treatment, ciprofloxacin or doxycycline may be added to this treat- ment for serious cases. To emphasize the necessity of taking precautions, an oropharyngeal and intestinal anthrax case due to consumption of infected and insufficiently cooked meat is presented below.展开更多
A dual-readout sensing platform based on two signal transduction channels can integrate the unique advantages of each sensing pattern,compensate for the deficiency in the adaptive capacity,and enable a more convincing...A dual-readout sensing platform based on two signal transduction channels can integrate the unique advantages of each sensing pattern,compensate for the deficiency in the adaptive capacity,and enable a more convincing performance in analytical applications.Here,we introduce a responsive molecule dye,xylenol orange(XO),to combine with lanthanide terbium ions(Tb^(3+)).The resultant Tb^(3+)-XO complex exhibited tunable optical properties and was used as a novel colorimetric and luminometric dual-readout sensing platform for assaying the anthrax biomarker,dipicolinic acid(DPA).In the presence of Tb^(3+),the XO solution underwent a color change from yellow to magenta;however,upon adding DPA,the color changed back to yellow immediately,accompanied by the characteristic luminescence emission of Tb^(3+).Considering the strong affinity between DPA/XO and metal ions,the proposed sensing platform was further employed for the determination and differentiation of certain metal ions using linear discriminant analysis.This convenient dual-readout sensing platform offers several notable features and significantly promotes the application and development of lanthanide-based materials.展开更多
Background:Anthrax is an acute zoonotic infectious disease caused by the bacterium known as Bacillus anthracis.From 26 July to 8 August 2015,an outbreak with 20 suspected cutaneous anthrax cases was reported in Ganqua...Background:Anthrax is an acute zoonotic infectious disease caused by the bacterium known as Bacillus anthracis.From 26 July to 8 August 2015,an outbreak with 20 suspected cutaneous anthrax cases was reported in Ganquan County,Shaanxi province in China.The genetic source tracking analysis of the anthrax outbreak was performed by molecular epidemiological methods in this study.Methods:Three molecular typing methods,namely canonical single nucleotide polymorphisms(canSNP),multiple-locus variable-number tandem repeat analysis(MLVA),and single nucleotide repeat(SNR)analysis,were used to investigate the possible source of transmission and identify the genetic relationship among the strains isolated from human cases and diseased animals during the outbreak.Results:Five strains isolated from diseased mules were clustered together with patients’isolates using canSNP typing and MLVA.The causative B.anthracis lineages in this outbreak belonged to the A.Br.001/002 canSNP subgroup and the MLVA15-31 genotype(the 31 genotype in MLVA15 scheme).Because nine isolates from another four provinces in China were clustered together with outbreak-related strains by the canSNP(A.Br.001/002 subgroup)and MLVA15 method(MLVA15-31 genotype),still another SNR analysis(CL10,CL12,CL33,and CL35)was used to source track the outbreak,and the results suggesting that these patients in the anthrax outbreak were probably infected by the same pathogen clone.Conclusions:It was deduced that the anthrax outbreak occurred in Shaanxi province,China in 2015 was a local occurrence.展开更多
文摘The aim of this study is to express the receptor-binding domain of Bacillus anthracis protective antigen in E.coli . Signal sequence of the outer membrane protein A (OmpA) of E.coli was attached to the 5′ end of the gene encoding protective antigen receptor-binding domain (the 4 th domain of PA, PAD4). The plasmid carrying the fusion gene was then transformed into E.coli and induced to express recombinant PAD4 by IPTG. The recombinant protein was purified by chromatography and then identified by N-terminal sequencing and Western blot. The recombinant protein, about 10% of the total bacterial protein in volume, was secreted to the periplasmic space of the cell. After a purification procedure including ion-exchange chromatography and gel filtration, about 10 mg of homogenous recombinant PAD4 was obtained from 1 L culture. Data from N-terminal sequencing suggested that the amino acid sequence of recombinant PAD4 was identical with its natural counterpart. And the result of Western blot showed the recombinant protein could bind with anti-PA serum from rabbit. High level secreted expression of PAD4 was obtained in E.coli . The results reported here are parts of a continuing research to evaluate PAD4 as a potential drug for anthrax therapy or a candidate of new vaccine.
文摘Background Anthrax,a zoonotic disease caused by the spore-forming bacterium Bacillus anthracis,remains a major global public health concern,especially in countries with limited resources.Sierra Leone,a West African country historically plagued by anthrax,has almost been out of report on this disease in recent decades.In this study,we described a large-scale anthrax outbreak affecting both animals and humans and attempted to characterize the path-ogenusingmoleculartechniques.Methods The causative agent of the animal outbreak in Port Loko District,Sierra Leone,between March and May 2022 was identified using the nanopore sequencing technique.A nationwide active surveillance was implemented from May 2022 to June 2023 to monitor the occurrence of anthrax-specific symptoms in humans.Suspected cases were subsequently verified using quantitative polymerase chain reaction.Full-genome sequencing was accomplished by combining long-read and short-read sequencing methods.Subsequent phylogenetic analysis was performed based on the full-chromosome single nucleotide polymorphisms.Results The outbreak in Port Loko District,Sierra Leone,led to the death of 233 animals between March 26th and May 16th,2022.We ruled out the initial suspicion of Anaplasma species and successfully identified B.anthracis as the causative agent of the outbreak.As a result of the government's prompt response,out of the 49 suspected human cases identifed during the one-year active surveillance,only 6 human cases tested positive,all within the frst month after the official declaration of the outbreak.The phylogenetic analysis indicated that the BaSL2022 isolate responsible for the outbreak was positioned in the A.Br.153 clade within the TransEuroAsian group of B.anthracis.Conclusions We successfully identifed a large-scale anthrax outbreak in Sierra Leone.The causative isolate of B.anthracis,BaSL2022,phylogenetically bridged other lineages in A.Br.153 clade and neighboring genetic groups,A.Br.144 and A.Br.148,eventually confirming the spillover of anthrax from West Africa.Given the wide dissemination of B.anthracis spores,it is highly advisable to effectively monitor the potential reoccurrence of anthrax outbreaks and to launch campaigns to improve public awareness regarding anthrax in Sierra Leone.
基金supported by the US Army Research Office(ARO)(#W911NF-10-1-0160)support from the Golden Leaf Foundation for major research instruments and facilities
文摘Multi-walled carbon nanotube（MWCNT） sheet was fabricated from a drawable MWCNT forest and then deposited on poly（methyl methacrylate） film. The film was further coated with a natural antimicrobial peptide nisin. We studied the effects of nisin coating on the attachment of Bacillus anthracis spores, the germination of attached spores, and the subsequent biofilm formation from attached spores. It was found that the strong adsorptivity and the super hydrophobicity of MWCNTs provided an ideal platform for nisin coating. Nisin coating on MWCNT sheets decreased surface hydrophobicity, reduced spore attachment, and reduced the germination of attached spores by 3.5 fold, and further inhibited the subsequent biofilm formation by 94.6% compared to that on uncoated MWCNT sheet. Nisin also changed the morphology of vegetative cells in the formed biofilm.The results of this study demonstrated that the anti-adhesion and antimicrobial effect of nisin in combination with the physical properties of carbon nanotubes had the potential in producing effective anti-biofilm formation surfaces.
基金This work was supported by National Institutesof Health Grants (1-R21-AI58002-01, R01-CA79820,R01-AI50150, P30-AR050948, 1-R43-AI-47558-01A2and R01 CA86172-01), a Dermatology FoundationGrant, a VA Grant 18-103-02, an Office of NavalResearch Grant N00014-01-1-0945, a Department ofDefense Grant APN 07363, a SERCEB grant 5 U54AI057157-02, and the UAB Comprehensive CancerCenter of USA.
文摘In this review, we advance a new concept in developing vaccines and/or drugs to target speci?c proteins expressed during the early stage of Bacillus anthracis (an- thrax) infection and address existing challenges to this concept. Three proteins (immune inhibitor A, GPR-like spore protease, and alanine racemase) initially identi?ed by proteomics in our laboratory were found to have di?erential expres- sions during anthrax spore germination and early outgrowth. Other studies of di?erent bacillus strains indicate that these three proteins are involved in either germination or cytotoxicity of spores, suggesting that they may serve as potential targets for the design of anti-anthrax vaccines and drugs.
文摘Anthrax which is caused by Bacillus anthracis is typically a disease of herbivores. Spores existing in the skin, meat, hair or mouth and nose of animals are transmitted to humans through contact with a break in the skin, consumption of infected meat or inhalation of spores [1]. Infected uncooked or insufficiently cooked meats cause oropharyngeal and gastrointestinal system (GIS) anthrax. When this infected materials swallowed anthrax spores may cause lesions from the oral cavity to the caecum. The diagnosis of gastrointestinal system (GIS) anthrax is difficult due to insidious clinical progression of the disease and difficulty in the isolation of agent pathogen. Releated symptoms of GIS anthrax are sore throat, neck swelling, diffuculty swallowing, stomach pain, anoreksia, bloody diarrhea, nause, bloody vomiting and fever. Supportive and antibiotic treatments are required. Benzylpenicillin, rifampicin, clindamycin, chloramphenicol, imipenem/cilastatin, or vancomycin can be use for treatment, ciprofloxacin or doxycycline may be added to this treat- ment for serious cases. To emphasize the necessity of taking precautions, an oropharyngeal and intestinal anthrax case due to consumption of infected and insufficiently cooked meat is presented below.
基金funded by the National Natural Science Foundation of China(No.21804083)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2018258)。
文摘A dual-readout sensing platform based on two signal transduction channels can integrate the unique advantages of each sensing pattern,compensate for the deficiency in the adaptive capacity,and enable a more convincing performance in analytical applications.Here,we introduce a responsive molecule dye,xylenol orange(XO),to combine with lanthanide terbium ions(Tb^(3+)).The resultant Tb^(3+)-XO complex exhibited tunable optical properties and was used as a novel colorimetric and luminometric dual-readout sensing platform for assaying the anthrax biomarker,dipicolinic acid(DPA).In the presence of Tb^(3+),the XO solution underwent a color change from yellow to magenta;however,upon adding DPA,the color changed back to yellow immediately,accompanied by the characteristic luminescence emission of Tb^(3+).Considering the strong affinity between DPA/XO and metal ions,the proposed sensing platform was further employed for the determination and differentiation of certain metal ions using linear discriminant analysis.This convenient dual-readout sensing platform offers several notable features and significantly promotes the application and development of lanthanide-based materials.
基金This work was supported by the National Priority Development Project on Key Science Instrument(no.2012YQ09019706)the Ministry of Science and the National Science and Technology Mega-Projects of China(nos.2012ZX10004215 and 2013ZX 10004-101).
文摘Background:Anthrax is an acute zoonotic infectious disease caused by the bacterium known as Bacillus anthracis.From 26 July to 8 August 2015,an outbreak with 20 suspected cutaneous anthrax cases was reported in Ganquan County,Shaanxi province in China.The genetic source tracking analysis of the anthrax outbreak was performed by molecular epidemiological methods in this study.Methods:Three molecular typing methods,namely canonical single nucleotide polymorphisms(canSNP),multiple-locus variable-number tandem repeat analysis(MLVA),and single nucleotide repeat(SNR)analysis,were used to investigate the possible source of transmission and identify the genetic relationship among the strains isolated from human cases and diseased animals during the outbreak.Results:Five strains isolated from diseased mules were clustered together with patients’isolates using canSNP typing and MLVA.The causative B.anthracis lineages in this outbreak belonged to the A.Br.001/002 canSNP subgroup and the MLVA15-31 genotype(the 31 genotype in MLVA15 scheme).Because nine isolates from another four provinces in China were clustered together with outbreak-related strains by the canSNP(A.Br.001/002 subgroup)and MLVA15 method(MLVA15-31 genotype),still another SNR analysis(CL10,CL12,CL33,and CL35)was used to source track the outbreak,and the results suggesting that these patients in the anthrax outbreak were probably infected by the same pathogen clone.Conclusions:It was deduced that the anthrax outbreak occurred in Shaanxi province,China in 2015 was a local occurrence.
