Vibrio parahaemolyticus is the main cause of foodborne gastroenteritis,which is widely distributed in shellfish and other seafood.Most V.parahaemolyticus are nonpathogenic,and only a few types,such as serotype O3:K6,a...Vibrio parahaemolyticus is the main cause of foodborne gastroenteritis,which is widely distributed in shellfish and other seafood.Most V.parahaemolyticus are nonpathogenic,and only a few types,such as serotype O3:K6,are pathogenic,which is also the most prevalent strain in Asia.However,the relationship between this serotype and pathogenicity has yet to be established.The waaf gene is located in the O antigen synthesis gene cluster.Thus,we constructed a waaf gene deletion mutant(i.e.,Δwaaf)of wild-type(WT)which isolated from shellfish serotype O3:K6 via chitin-mediated transformation technology.We then constructed theΔwaaf complementary strain(i.e.,C-△waaf)via the Escherichia coli S17λpir strain by conjugation.The basic physiological characteristics,adhesion to Caco2 cells,and pathogenicity of the WT,△waaf,and C-△waaf strains were compared.Growth curves showed no remarkable differences between the WT andΔwaaf strains.However,theΔwaaf strain non-reactive to O3 antisera and other 12 O-group antisera of V.parahaemolyticus.Moreover,the number of flgella and extracellular polysaccharides decreased,the adhesion decreased,and the pathogenicity weakened.These characteristics of the C-△waaf strain were similar to those of the WT strain These results indicated that the waaf gene is vital to the serotype in V.parahaemolyticus,and changes in O antigen could affect the pathogenicity of this bacterium.This study will be helpful to understand the pathogenic mechanism of V.parahaemolyticus.展开更多
Promoting metallic magnesium(Mg)-based implants to treat bone diseases in clinics,such as osteosarcoma and bacterial infection,remains a challenging topic.Herein,an iron hydroxide-based composite coating with a twosta...Promoting metallic magnesium(Mg)-based implants to treat bone diseases in clinics,such as osteosarcoma and bacterial infection,remains a challenging topic.Herein,an iron hydroxide-based composite coating with a twostage nanosheet-like structure was fabricated on Mg alloy,and this was followed by a thermal reduction treatment to break some of the surface Fe–OH bonds.The coating demonstrated three positive changes in properties due to the defects.First,the removal of–OH made the coating superhydrophobic,and it had self-cleaning and antifouling properties.This is beneficial for keeping the implants clean and for anti-corrosion before implantation into the human body.Furthermore,the superhydrophobicity could be removed by immersing the implant in a 75%ethanol solution,to further facilitate biological action during service.Second,the color of the coating changed from yellow to brown-black,leading to an increase in the light absorption,which resulted in an excellent photothermal effect.Third,the defects increased the Fe2+content in the coating and highly improved peroxidase activity.Thus,the defect coating exhibited synergistic photothermal/chemodynamic therapeutic effects for bacteria and tumors.Moreover,the coating substantially enhanced the anti-corrosion and biocompatibility of the Mg alloys.Therefore,this study offers a novel multi-functional Mg-based implant for osteosarcoma therapy.展开更多
The application of Fe-Mn-modified biochar for the remediation of Cd-contaminated soil over long time periods has been little studied.In this paper,we describe the performance of coconut-shell-derived biochar modified ...The application of Fe-Mn-modified biochar for the remediation of Cd-contaminated soil over long time periods has been little studied.In this paper,we describe the performance of coconut-shell-derived biochar modified with ferromanganese in relation to soil Cd stabilization and rice Cd bioaccumulation during a 3-year laboratory study.Different application dosages(0.05-0.5 wt%)and different rice varieties(the early and late rice)are also considered.The results show that ferromanganese is mainly loaded in biochar pores as MnFe_(2)O_(4),and that it decreases the specific surface area(SSA)and total pore volume of biochar.Ferromanganese biochar(0.5 wt%)applied to paddy soil is more effective than the same dose of pristine biochar in decreasing the soil-exchangeable Cd fraction(27.42-41.92%vs 22.56-33.85%),predominantly by decreasing soil Eh and increasing root Fe plaques.Ferromanganese biochar application helps to reduce Cd bioaccumulation in rice,especially in the grain(up to 48.6%-61.0%),and grain Cd levels(0.2 mg/kg)are all within the acceptable limit for food security in China.It is shown that ferromanganese modification and application can maintain soil at low redox status,keep root Fe plaques at a high level,and may also increase the stability of pristine biochar.All of these effects contribute to maintaining its high remediation efficiency over a 3-year inoculation period.The results presented in this paper demonstrate the potential appli-cations of ferromanganese biochar in soil remediation and the improvement of food safety.展开更多
Osteosarcoma(OS)is a malignant tumor with a high rate of recurrence.Recently,biodegradable Mg-based implants have become a new therapeutic platform for bone-related diseases.However,poor biosafety and deficient intell...Osteosarcoma(OS)is a malignant tumor with a high rate of recurrence.Recently,biodegradable Mg-based implants have become a new therapeutic platform for bone-related diseases.However,poor biosafety and deficient intelligent tumor-killing ability of Mg-based implants are still the main challenges for the pre-cise treatment of OS.Herein,based on the excellent catalytic and photothermal conversion properties of nanozyme ferric oxide(Fe_(3)O_(4)),a novel two-step hydrothermal method for in situ preparation of Fe_(3)O_(4)nanosheets on the surface of plasma electrolytic oxidation(PEO)-treated Mg alloy using Mg-Fe layered double hydroxides(Mg-Fe LDH)as precursor was proposed.Compared with Mg alloy,there were no obvious corrosion cracks on the surface of Fe_(3)O_(4)nanosheets-coated Mg alloy(Fe_(3)O_(4)-NS)immersed in 0.9 wt.%NaCl for 14 days,which demonstrated the corrosion resistance of Mg alloy was significantly enhanced.Cytocompatibility experiments and hemolysis assay confirmed the great biocompatibility of Fe_(3)O_(4)-NS,especially,hemolysis ratio was lower than 1%.Meanwhile,Fe_(3)O_(4)-NS presented excellent cat-alytic oxidation capacity in the presence of H_(2)O_(2),and its temperature can significantly increase from 27℃to approximately 56℃under NIR irradiation.Therefore,intelligent responsive Fe_(3)O_(4)nanosheets-engineered Mg-based implants demonstrated excellent antitumor properties in vivo and in vitro due to their photothermal and chemodynamic synergetic effects.This study provides a novel approach for the preparation of Fe_(3)O_(4)coatings on the surface of Mg alloys and a new strategy for the treatment of OS.展开更多
Osteosarcoma (OS) tissue resection with distinctive bactericidal activity, followed by regeneration of bone de-fects, is a highly demanded clinical treatment. Biodegradable Mg-based implants with desirable osteopromot...Osteosarcoma (OS) tissue resection with distinctive bactericidal activity, followed by regeneration of bone de-fects, is a highly demanded clinical treatment. Biodegradable Mg-based implants with desirable osteopromotive and superior mechanical properties to polymers and ceramics are promising new platforms for treating bone-related diseases. Integration of biodegradation control, osteosarcoma destruction, anti-bacteria, and bone defect regeneration abilities on Mg-based implants by applying biosafe and facile strategy is a promising and challenging topic. Here, a black Mn-containing layered double hydroxide (LDH) nanosheet-modified Mg-based implants was developed. Benefiting from the distinctive capabilities of the constructed black LDH film, including near-infrared optical absorption and reactive oxygen species (ROS) generation in a tumor-specific microenvi-ronment, the tumor cells and tissue could be effectively eliminated. Concomitant bacteria could be killed by localized hyperthermia. Furthermore, the enhanced corrosion resistance and synergistic biofunctions of Mn and Mg ions of the constructed black LDH-modified Mg implants significantly facilitated cell adhesion, spreading and proliferation and osteogenic differentiation in vitro, and accelerated bone regeneration in vivo. This work offers a new platform and feasible strategy for OS therapeutics and bone defect regeneration, which broadens the biomedical application of Mg-based alloys.展开更多
基金supported by grants from the Natural Science Foundation of Chongqing(cstc2020jcyj-msxm X0685)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202001231)+1 种基金the National Natural Science Foundation of China(NSFC)(No.31201372)Science and Technology Project of Wanzhou in 2020。
文摘Vibrio parahaemolyticus is the main cause of foodborne gastroenteritis,which is widely distributed in shellfish and other seafood.Most V.parahaemolyticus are nonpathogenic,and only a few types,such as serotype O3:K6,are pathogenic,which is also the most prevalent strain in Asia.However,the relationship between this serotype and pathogenicity has yet to be established.The waaf gene is located in the O antigen synthesis gene cluster.Thus,we constructed a waaf gene deletion mutant(i.e.,Δwaaf)of wild-type(WT)which isolated from shellfish serotype O3:K6 via chitin-mediated transformation technology.We then constructed theΔwaaf complementary strain(i.e.,C-△waaf)via the Escherichia coli S17λpir strain by conjugation.The basic physiological characteristics,adhesion to Caco2 cells,and pathogenicity of the WT,△waaf,and C-△waaf strains were compared.Growth curves showed no remarkable differences between the WT andΔwaaf strains.However,theΔwaaf strain non-reactive to O3 antisera and other 12 O-group antisera of V.parahaemolyticus.Moreover,the number of flgella and extracellular polysaccharides decreased,the adhesion decreased,and the pathogenicity weakened.These characteristics of the C-△waaf strain were similar to those of the WT strain These results indicated that the waaf gene is vital to the serotype in V.parahaemolyticus,and changes in O antigen could affect the pathogenicity of this bacterium.This study will be helpful to understand the pathogenic mechanism of V.parahaemolyticus.
基金the National Key R&D Program of China(2021YFC2400500)Shanghai Committee of Science and Technology,China(20S31901200)+1 种基金GDPH Supporting Fund for Talent Program(KY0120220137 and KY012021462)Postdoctoral Science Foundation of China(2022M723288).
文摘Promoting metallic magnesium(Mg)-based implants to treat bone diseases in clinics,such as osteosarcoma and bacterial infection,remains a challenging topic.Herein,an iron hydroxide-based composite coating with a twostage nanosheet-like structure was fabricated on Mg alloy,and this was followed by a thermal reduction treatment to break some of the surface Fe–OH bonds.The coating demonstrated three positive changes in properties due to the defects.First,the removal of–OH made the coating superhydrophobic,and it had self-cleaning and antifouling properties.This is beneficial for keeping the implants clean and for anti-corrosion before implantation into the human body.Furthermore,the superhydrophobicity could be removed by immersing the implant in a 75%ethanol solution,to further facilitate biological action during service.Second,the color of the coating changed from yellow to brown-black,leading to an increase in the light absorption,which resulted in an excellent photothermal effect.Third,the defects increased the Fe2+content in the coating and highly improved peroxidase activity.Thus,the defect coating exhibited synergistic photothermal/chemodynamic therapeutic effects for bacteria and tumors.Moreover,the coating substantially enhanced the anti-corrosion and biocompatibility of the Mg alloys.Therefore,this study offers a novel multi-functional Mg-based implant for osteosarcoma therapy.
基金This work was financially supported by the National Key Research and Development Program of China(2017YFD0801505)National Natural Science Foundation of China(NSFC)(No.41907015)+1 种基金China Postdoctoral Science Foundation(2019M662782)Scientific Research Fund of Hunan Provincial Education Department,China(18B120).
文摘The application of Fe-Mn-modified biochar for the remediation of Cd-contaminated soil over long time periods has been little studied.In this paper,we describe the performance of coconut-shell-derived biochar modified with ferromanganese in relation to soil Cd stabilization and rice Cd bioaccumulation during a 3-year laboratory study.Different application dosages(0.05-0.5 wt%)and different rice varieties(the early and late rice)are also considered.The results show that ferromanganese is mainly loaded in biochar pores as MnFe_(2)O_(4),and that it decreases the specific surface area(SSA)and total pore volume of biochar.Ferromanganese biochar(0.5 wt%)applied to paddy soil is more effective than the same dose of pristine biochar in decreasing the soil-exchangeable Cd fraction(27.42-41.92%vs 22.56-33.85%),predominantly by decreasing soil Eh and increasing root Fe plaques.Ferromanganese biochar application helps to reduce Cd bioaccumulation in rice,especially in the grain(up to 48.6%-61.0%),and grain Cd levels(0.2 mg/kg)are all within the acceptable limit for food security in China.It is shown that ferromanganese modification and application can maintain soil at low redox status,keep root Fe plaques at a high level,and may also increase the stability of pristine biochar.All of these effects contribute to maintaining its high remediation efficiency over a 3-year inoculation period.The results presented in this paper demonstrate the potential appli-cations of ferromanganese biochar in soil remediation and the improvement of food safety.
基金This work is financially supported by the National Natu-ral Science Foundation of China(Nos.51901239 and 52001076)the Shanghai Committee of Science and Technology,China(No.20S31901200)+1 种基金the S&T Innovation 2025 Major Special Programme of Ningbo(No.2020Z095)the S&T Industrial Programme of Cixi(No.2019gy01).
文摘Osteosarcoma(OS)is a malignant tumor with a high rate of recurrence.Recently,biodegradable Mg-based implants have become a new therapeutic platform for bone-related diseases.However,poor biosafety and deficient intelligent tumor-killing ability of Mg-based implants are still the main challenges for the pre-cise treatment of OS.Herein,based on the excellent catalytic and photothermal conversion properties of nanozyme ferric oxide(Fe_(3)O_(4)),a novel two-step hydrothermal method for in situ preparation of Fe_(3)O_(4)nanosheets on the surface of plasma electrolytic oxidation(PEO)-treated Mg alloy using Mg-Fe layered double hydroxides(Mg-Fe LDH)as precursor was proposed.Compared with Mg alloy,there were no obvious corrosion cracks on the surface of Fe_(3)O_(4)nanosheets-coated Mg alloy(Fe_(3)O_(4)-NS)immersed in 0.9 wt.%NaCl for 14 days,which demonstrated the corrosion resistance of Mg alloy was significantly enhanced.Cytocompatibility experiments and hemolysis assay confirmed the great biocompatibility of Fe_(3)O_(4)-NS,especially,hemolysis ratio was lower than 1%.Meanwhile,Fe_(3)O_(4)-NS presented excellent cat-alytic oxidation capacity in the presence of H_(2)O_(2),and its temperature can significantly increase from 27℃to approximately 56℃under NIR irradiation.Therefore,intelligent responsive Fe_(3)O_(4)nanosheets-engineered Mg-based implants demonstrated excellent antitumor properties in vivo and in vitro due to their photothermal and chemodynamic synergetic effects.This study provides a novel approach for the preparation of Fe_(3)O_(4)coatings on the surface of Mg alloys and a new strategy for the treatment of OS.
基金This work is financially supported by the National Key R&D Program of China(2021YFC2400500)National Natural Science Foundation of China(31771044)+3 种基金Shanghai Committee of Science and Technology,China(19JC1415500 and 20S31901200)High-end Entrepreneurial and Innovative Teams of Ningbo High-level Talents Project(2018A-09-C)S&T Innovation 2025 Major Special Programme of Ningbo(2020Z095)S&T Industrial Programme of Cixi(2019gy01).
文摘Osteosarcoma (OS) tissue resection with distinctive bactericidal activity, followed by regeneration of bone de-fects, is a highly demanded clinical treatment. Biodegradable Mg-based implants with desirable osteopromotive and superior mechanical properties to polymers and ceramics are promising new platforms for treating bone-related diseases. Integration of biodegradation control, osteosarcoma destruction, anti-bacteria, and bone defect regeneration abilities on Mg-based implants by applying biosafe and facile strategy is a promising and challenging topic. Here, a black Mn-containing layered double hydroxide (LDH) nanosheet-modified Mg-based implants was developed. Benefiting from the distinctive capabilities of the constructed black LDH film, including near-infrared optical absorption and reactive oxygen species (ROS) generation in a tumor-specific microenvi-ronment, the tumor cells and tissue could be effectively eliminated. Concomitant bacteria could be killed by localized hyperthermia. Furthermore, the enhanced corrosion resistance and synergistic biofunctions of Mn and Mg ions of the constructed black LDH-modified Mg implants significantly facilitated cell adhesion, spreading and proliferation and osteogenic differentiation in vitro, and accelerated bone regeneration in vivo. This work offers a new platform and feasible strategy for OS therapeutics and bone defect regeneration, which broadens the biomedical application of Mg-based alloys.
