Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica...Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica, salamae, arizonae,展开更多
Objective:To establish a polymerase chain reaction(PCR) technique based on cytochrome b {cytb) gene of mitochondria DNA(mtDNA) for blood meal identification.Methods:The PCR technique was established based on published...Objective:To establish a polymerase chain reaction(PCR) technique based on cytochrome b {cytb) gene of mitochondria DNA(mtDNA) for blood meal identification.Methods:The PCR technique was established based on published information and validated using blood sample of laboratory animals of which their whole gene sequences are available in CenBank.PCR was next performed to compile gene sequences of different species of wild rodents.The primers used were complementary to the conserved region of the cytb gene of vertebrate's mtDNA.A total of 100 blood samples,both from laboratory animals and wild rodents were collected und analyzed.The obtained unknown sequences were compared with those in the GenBank database using BLAST program to identify the vertebrate animal species.Results:Gene sequences of 11 species of wild animals caught in 9 localities of Peninsular Malaysia were compiled using the established PCR. The animals involved were Rattus(rattus) tanezumi,Rattus tiomanicus,Leopoldamys sabanus, Tupaia glis,Tupaia minor,Niviventor cremoriventor,Rhinosciurus laticaudatus,Calloseiurus caniseps,Sundamys muelleri,Rattus rajah,and Maxomys whitelwadi.The BLAST results confirmed the host with exact or nearly exact matches(>89%identity).Ten new gene sequences have been deposited in CenBank database since September 2010.Conclusions:This study indicates that the PCR direct sequencing system using universal primer sets for vertebrate cytb gene is a promising technique for blood meal identification.展开更多
Fungi play a significant role in biology-related domains, and with the molecular biology technology advancing, identification of fungi at molecular level and verification of genetic transformant has become the necessa...Fungi play a significant role in biology-related domains, and with the molecular biology technology advancing, identification of fungi at molecular level and verification of genetic transformant has become the necessary step of test. By far, however, there is no ideal high-throughput molecular identification method. In this paper, a high-throughput device was designed, and a novel PCR-mediated molecular identification method suitable for the device was developed. Through cloning of ccllulase encoding genes and regulatory genes on the genome of Trichoderma reesei, cloning of promoter of phesphoglycerate kinase gene 1 and xylanase encoding genes on the genome and expression vector of Saccharomyces cerevisiae, and ITS sequences cloning and RAPD analysis of T. reesei, S. cerevisiae, Penicil- lium oxalicum, Rhizopus stolonifer, Aspergillus niger, A. carbonarius and A. japonicas, the method turned out to be an effective one with wide application potential. The establishment of the method has worked out the bottleneck of high-throughput molecular identification.展开更多
Because of the high affinity of the same element Ti,cemented carbide tools containing Ti seem to be non⁃optimal in machining titanium alloys.However,in practice,cemented carbide tools containing Ti are still widely us...Because of the high affinity of the same element Ti,cemented carbide tools containing Ti seem to be non⁃optimal in machining titanium alloys.However,in practice,cemented carbide tools containing Ti are still widely used in machining titanium alloys.Cutting experiments were conducted in order to systematically explain the contradictions between the practice and theory.The diffusion process between titanium alloys and the cemented carbide tools was analyzed by auger electron spectroscopy detecting the cutting regions.It was also analyzed by Ti/Co diffusion behavior simulated by molecular thermodynamics.The experimental results and the simulation results showed that the mutual diffusion of Ti/Co atoms was the major reason for the diffusion wear.The dissolution⁃diffusion wear was one of the main wear mechanisms for the cemented carbide tools containing Ti in the coatings.Moreover,four types of cemented carbide tools and two other types of cermet tools were used to machine the Ti⁃6Al⁃4V alloys at different cutting speeds to further verify the high affinity of cutting tools containing Ti in the substrate/coating.The verification experiments results showed that the cemented carbide tools containing Ti generally cannot be used for machining titanium alloys,but could show less affinity in the cutting regions with reasonable cutting conditions.展开更多
Tick-borne diseases(TBDs) are a major public health concern that has increased in the past three decades. Nevertheless, emerging or reemerging TBDs may be still misdiagnosed. Molecular biology techniques for the scree...Tick-borne diseases(TBDs) are a major public health concern that has increased in the past three decades. Nevertheless, emerging or reemerging TBDs may be still misdiagnosed. Molecular biology techniques for the screening of ticks, use of "Omics" approaches and the incorporation of analytical methods such as mass spectrometry or nuclear magnetic resonance, to the study of ticks and their associated pathogens or potential pathogens are promising tools for a more accurate differential diagnosis of TBDs. However, this huge amount of data needs to be carefully interpreted before being incorporated to the routine of clinical practice. In the meantime, a clinical approach and high level of suspicion keep being essential for the diagnosis and proper handling of TBDs.展开更多
As one of the most important cereals,wheat(Triticum aestivum)has high nutritional value and is widely cultivated in China.However,wheat can cause severe allergic reactions,and a growing number of people are developing...As one of the most important cereals,wheat(Triticum aestivum)has high nutritional value and is widely cultivated in China.However,wheat can cause severe allergic reactions,and a growing number of people are developing allergies to Chinese wheat.Low molecular weight glutenin(LMW-GS),an important allergen in susceptible populations,is responsible for celiac disease and wheat contacts dermatitis.In this study,LMW-GS was highly purified from Chinese wheat(Xiaoyan 6)and further identified and characterized.In addition,8 peptides were predicted efficiently by 5 immunological tools,among which 5 peptides showed significant immunoglobulin E binding abilities.Two specific epitopes were found to be in the non-conserved region of the amino acid sequence of LMW-GS,which was speculated to be the specific epitope of Chinese wheat.This systematic research of LMW-GS may provide new insights into the prevention of wheat allergy and development of hypoallergenic wheat products.展开更多
Finding energetic materials with tailored properties is always a significant challenge due to low research efficiency in trial and error.Herein,a methodology combining domain knowledge,a machine learning algorithm,and...Finding energetic materials with tailored properties is always a significant challenge due to low research efficiency in trial and error.Herein,a methodology combining domain knowledge,a machine learning algorithm,and experiments is presented for accelerating the discovery of novel energetic materials.A high-throughput virtual screening(HTVS)system integrating on-demand molecular generation and machine learning models covering the prediction of molecular properties and crystal packing mode scoring is established.With the proposed HTVS system,candidate molecules with promising properties and a desirable crystal packing mode are rapidly targeted from the generated molecular space containing 25112 molecules.Furthermore,a study of the crystal structure and properties shows that the good comprehensive performances of the target molecule are in agreement with the predicted results,thus verifying the effectiveness of the proposed methodology.This work demonstrates a new research paradigm for discovering novel energetic materials and can be extended to other organic materials without manifest obstacles.展开更多
Anisotropy is one central influencing factor on achievable ultimate machined surface integrity of metallic materials.Specifically,grain boundary has a strong impact on the deformation behaviour of polycrystalline mate...Anisotropy is one central influencing factor on achievable ultimate machined surface integrity of metallic materials.Specifically,grain boundary has a strong impact on the deformation behaviour of polycrystalline materials and correlated material removal at the microscale.In the present work,we perform molecular dynamics simulations and experiments to elucidate the underlying grain boundaryassociated mechanisms and their correlations with machining results of a bi-crystal Cu under nanocutting using a Berkovich tool.Specifically,crystallographic orientations of simulated bi-crystal Cu with a misorientation angle of 44.1°are derived from electron backscatter diffraction characterization of utilized polycrystalline copper specimen.Simulation results reveal that blocking of dislocation motion at grain boundaries,absorption of dislocations by grain boundaries and dislocation nucleation from grain boundaries are operating deformation modes in nanocutting of the bi-crystal Cu.Furthermore,heterogeneous grain boundary-associated mechanisms in neighbouring grains lead to strong anisotropic machining behaviour in the vicinity of the grain boundary.Simulated machined surface morphology and machining force evolution in the vicinity of grain boundary qualitatively agree well with experimental results.It is also found that the geometry of Berkovich tool has a strong impact on grain boundary-associated mechanisms and resultant ploughing-induced surface pile-up phenomenon.展开更多
Mycobacterium tuberculosis, a Gram-positive bacterium of great clinical relevance, is a lethal pathogen owing to its complex physiological characteristics and development of drug resistance. Several molecular genetic ...Mycobacterium tuberculosis, a Gram-positive bacterium of great clinical relevance, is a lethal pathogen owing to its complex physiological characteristics and development of drug resistance. Several molecular genetic tools have been developed in the past few decades to study this microorganism. These tools have been instrumental in understanding how M. tuberculosis became a successful pathogen. Advanced molecular genetic tools have played a significant role in exploring the complex pathways involved in M. tuberculosis pathogenesis. Here, we review various molecular genetic tools used in the study of M. tuberculosis. Further, we discuss the applications of clustered regularly interspaced short palindromic repeat interference(CRISPRi), a novel technology recently applied in M. tuberculosis research to study target gene functions. Finally, prospective outcomes of the applications of molecular techniques in the field of M. tuberculosis genetic research are also discussed.展开更多
基金financially supported by the University of Malaya Research Grant (UMRG) (RP003A-13BIO)UM Postgraduate Research Fund (PPP) (PS319/2010B)
文摘Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica, salamae, arizonae,
基金financially supported by a grant(JPP-IMR Code:09-030) from the Ministry of Health,Malaysia
文摘Objective:To establish a polymerase chain reaction(PCR) technique based on cytochrome b {cytb) gene of mitochondria DNA(mtDNA) for blood meal identification.Methods:The PCR technique was established based on published information and validated using blood sample of laboratory animals of which their whole gene sequences are available in CenBank.PCR was next performed to compile gene sequences of different species of wild rodents.The primers used were complementary to the conserved region of the cytb gene of vertebrate's mtDNA.A total of 100 blood samples,both from laboratory animals and wild rodents were collected und analyzed.The obtained unknown sequences were compared with those in the GenBank database using BLAST program to identify the vertebrate animal species.Results:Gene sequences of 11 species of wild animals caught in 9 localities of Peninsular Malaysia were compiled using the established PCR. The animals involved were Rattus(rattus) tanezumi,Rattus tiomanicus,Leopoldamys sabanus, Tupaia glis,Tupaia minor,Niviventor cremoriventor,Rhinosciurus laticaudatus,Calloseiurus caniseps,Sundamys muelleri,Rattus rajah,and Maxomys whitelwadi.The BLAST results confirmed the host with exact or nearly exact matches(>89%identity).Ten new gene sequences have been deposited in CenBank database since September 2010.Conclusions:This study indicates that the PCR direct sequencing system using universal primer sets for vertebrate cytb gene is a promising technique for blood meal identification.
基金Supported by Applied Fundamental Research Project of Guangxi Department of Science and Technology(14125008-2-13)
文摘Fungi play a significant role in biology-related domains, and with the molecular biology technology advancing, identification of fungi at molecular level and verification of genetic transformant has become the necessary step of test. By far, however, there is no ideal high-throughput molecular identification method. In this paper, a high-throughput device was designed, and a novel PCR-mediated molecular identification method suitable for the device was developed. Through cloning of ccllulase encoding genes and regulatory genes on the genome of Trichoderma reesei, cloning of promoter of phesphoglycerate kinase gene 1 and xylanase encoding genes on the genome and expression vector of Saccharomyces cerevisiae, and ITS sequences cloning and RAPD analysis of T. reesei, S. cerevisiae, Penicil- lium oxalicum, Rhizopus stolonifer, Aspergillus niger, A. carbonarius and A. japonicas, the method turned out to be an effective one with wide application potential. The establishment of the method has worked out the bottleneck of high-throughput molecular identification.
基金the National Science and Technology Major Project of China(Grant No.2019ZX04017001).
文摘Because of the high affinity of the same element Ti,cemented carbide tools containing Ti seem to be non⁃optimal in machining titanium alloys.However,in practice,cemented carbide tools containing Ti are still widely used in machining titanium alloys.Cutting experiments were conducted in order to systematically explain the contradictions between the practice and theory.The diffusion process between titanium alloys and the cemented carbide tools was analyzed by auger electron spectroscopy detecting the cutting regions.It was also analyzed by Ti/Co diffusion behavior simulated by molecular thermodynamics.The experimental results and the simulation results showed that the mutual diffusion of Ti/Co atoms was the major reason for the diffusion wear.The dissolution⁃diffusion wear was one of the main wear mechanisms for the cemented carbide tools containing Ti in the coatings.Moreover,four types of cemented carbide tools and two other types of cermet tools were used to machine the Ti⁃6Al⁃4V alloys at different cutting speeds to further verify the high affinity of cutting tools containing Ti in the substrate/coating.The verification experiments results showed that the cemented carbide tools containing Ti generally cannot be used for machining titanium alloys,but could show less affinity in the cutting regions with reasonable cutting conditions.
文摘Tick-borne diseases(TBDs) are a major public health concern that has increased in the past three decades. Nevertheless, emerging or reemerging TBDs may be still misdiagnosed. Molecular biology techniques for the screening of ticks, use of "Omics" approaches and the incorporation of analytical methods such as mass spectrometry or nuclear magnetic resonance, to the study of ticks and their associated pathogens or potential pathogens are promising tools for a more accurate differential diagnosis of TBDs. However, this huge amount of data needs to be carefully interpreted before being incorporated to the routine of clinical practice. In the meantime, a clinical approach and high level of suspicion keep being essential for the diagnosis and proper handling of TBDs.
基金financially supported by the State Key Research and Development Plan(2019YFC1605002)。
文摘As one of the most important cereals,wheat(Triticum aestivum)has high nutritional value and is widely cultivated in China.However,wheat can cause severe allergic reactions,and a growing number of people are developing allergies to Chinese wheat.Low molecular weight glutenin(LMW-GS),an important allergen in susceptible populations,is responsible for celiac disease and wheat contacts dermatitis.In this study,LMW-GS was highly purified from Chinese wheat(Xiaoyan 6)and further identified and characterized.In addition,8 peptides were predicted efficiently by 5 immunological tools,among which 5 peptides showed significant immunoglobulin E binding abilities.Two specific epitopes were found to be in the non-conserved region of the amino acid sequence of LMW-GS,which was speculated to be the specific epitope of Chinese wheat.This systematic research of LMW-GS may provide new insights into the prevention of wheat allergy and development of hypoallergenic wheat products.
基金the Science Challenge Project(TZ2018004)the National Natural Science Foundation of China(21875228 and 21702195)for financial support。
文摘Finding energetic materials with tailored properties is always a significant challenge due to low research efficiency in trial and error.Herein,a methodology combining domain knowledge,a machine learning algorithm,and experiments is presented for accelerating the discovery of novel energetic materials.A high-throughput virtual screening(HTVS)system integrating on-demand molecular generation and machine learning models covering the prediction of molecular properties and crystal packing mode scoring is established.With the proposed HTVS system,candidate molecules with promising properties and a desirable crystal packing mode are rapidly targeted from the generated molecular space containing 25112 molecules.Furthermore,a study of the crystal structure and properties shows that the good comprehensive performances of the target molecule are in agreement with the predicted results,thus verifying the effectiveness of the proposed methodology.This work demonstrates a new research paradigm for discovering novel energetic materials and can be extended to other organic materials without manifest obstacles.
基金The authors greatly acknowledge support from the Science Challenge Project(Nos.TZ2018006-0201-02 and TZ2018006-0205-02)the Fundamental Research Funds for the Central Universities.
文摘Anisotropy is one central influencing factor on achievable ultimate machined surface integrity of metallic materials.Specifically,grain boundary has a strong impact on the deformation behaviour of polycrystalline materials and correlated material removal at the microscale.In the present work,we perform molecular dynamics simulations and experiments to elucidate the underlying grain boundaryassociated mechanisms and their correlations with machining results of a bi-crystal Cu under nanocutting using a Berkovich tool.Specifically,crystallographic orientations of simulated bi-crystal Cu with a misorientation angle of 44.1°are derived from electron backscatter diffraction characterization of utilized polycrystalline copper specimen.Simulation results reveal that blocking of dislocation motion at grain boundaries,absorption of dislocations by grain boundaries and dislocation nucleation from grain boundaries are operating deformation modes in nanocutting of the bi-crystal Cu.Furthermore,heterogeneous grain boundary-associated mechanisms in neighbouring grains lead to strong anisotropic machining behaviour in the vicinity of the grain boundary.Simulated machined surface morphology and machining force evolution in the vicinity of grain boundary qualitatively agree well with experimental results.It is also found that the geometry of Berkovich tool has a strong impact on grain boundary-associated mechanisms and resultant ploughing-induced surface pile-up phenomenon.
基金supported by the National Mega-project of China for Innovative Drugs(2018ZX09721001-003-003)for Main Infectious Diseases(2017ZX10302301-003-002)+7 种基金the National Natural Science Foundation of China(No.81572037)the grants of Chinese Academy of Sciences(154144KYSB20150045,YJKYYQ20170036,KFZD-SW-207)the Public Research and Capacity Building Project of Guangdong Province(2017A020212004)partially supported by Guangzhou Municipal Industry and Research Collaborative Innovation Program(201508020248,201604020019)the Key Project(SKLRD2016ZJ003)from the State Key Lab of Respiratory Disease,Guangzhou Institute of Respiratory Diseases,First Affiliated Hospital of Guangzhou Medical UniversityT.Z.received support“Science and Technology Innovation Leader of Guangdong Province(2016TX03R095)”CAS-TWAS President's Ph D Fellowship Program(to C.C.and M.M.I.)UCAS Ph D Fellowship Program(to H.M.A.H.and J.M.)for International Students
文摘Mycobacterium tuberculosis, a Gram-positive bacterium of great clinical relevance, is a lethal pathogen owing to its complex physiological characteristics and development of drug resistance. Several molecular genetic tools have been developed in the past few decades to study this microorganism. These tools have been instrumental in understanding how M. tuberculosis became a successful pathogen. Advanced molecular genetic tools have played a significant role in exploring the complex pathways involved in M. tuberculosis pathogenesis. Here, we review various molecular genetic tools used in the study of M. tuberculosis. Further, we discuss the applications of clustered regularly interspaced short palindromic repeat interference(CRISPRi), a novel technology recently applied in M. tuberculosis research to study target gene functions. Finally, prospective outcomes of the applications of molecular techniques in the field of M. tuberculosis genetic research are also discussed.