[Objective] The biological characteristics and pathogenicities of Shewanella algae and Shewanella abalone from Babylonia were studied in this paper. [Method]The hemolytic bacteria were isolated from the hepatopancreas...[Objective] The biological characteristics and pathogenicities of Shewanella algae and Shewanella abalone from Babylonia were studied in this paper. [Method]The hemolytic bacteria were isolated from the hepatopancreas of Babylonia suffered from proboscis edema with blood agar plate. The dominant bacterial community in the ill Babylonia was identified by 16 S r DNA sequence analysis, and the bacterial cultural and biochemical characteristics and pathogenicities were studied. [Result]The Shewanella bacteria, including Shewanella algae and Shewanella abalone, are the dominant bacterial community in Babylonia suffered from proboscis edema.The colony characteristics of Shewanella algae in nutrient agar medium, TCBS agar medium and CHROMagar vibrio colored medium were similar to those of Shewanella abalone. Shewanella algae possessed β-hemolysis and Shewanella abalone possessed α-hemolysis in the blood agar plate. The biochemical reaction of Shewanella algae and Shewanella abalone was all of non-fermentation type. The results of artificial infection test showed that half lethal dose(LD50) of the test strains of Shewanella algae was 10-5.50/0.1 ml. The test strains of Shewanella algae have strong toxicity, and could cause mice and chickens to die of sepsis with mortality of100%. The mortality of Babylonia infected with Shewanella algae was 10%; while the survived Babylonia lost the ability of moving and intaking for a long time, but they were not suffered from proboscis edema. There was no death in mice or chicks infected with Shewanella abalone, but their livers and spleens were slightly hyperemic and swelling. There was also no death in Babylonia infected with Shewanella abalone, but their intaking and moving ability was lost for a short time.[Conclusion] Although Shewanella algae and Shewanella abalone were the dominant bacteria in Babylonia suffered from proboscis edema, they were not the main pathogenic bacteria for proboscis edema. Shewanella algae had strong pathogenicity to mice, chicks and Babylonia, while Shewanella abalone showed no marked pathogenicity to those experimental animals in this study.展开更多
[Objective] This study aimed to explore the biological characteristics of Col etotrichum gloeosporioides in pears. [Method] Twenty-five C. gloeosporioides strains were isolated and identified from the diseased samples...[Objective] This study aimed to explore the biological characteristics of Col etotrichum gloeosporioides in pears. [Method] Twenty-five C. gloeosporioides strains were isolated and identified from the diseased samples. Their pathogenicity was identified by inoculating the surface of punctured pears with fungal discs. The effects of different temperatures, pH values, carbon sources and nitrogen sources on the growth of C. gloeosporioides mycelia were explored by incubating fungal discs on the center of plates. [Result] Among the twenty-five C. gloeosporioides strains, three had strong pathogenicity, and eighteen had intermediate pathogenicity, and four strains had weak pathogenicity. Those highly-pathogenic strains had darker colonies, with dense mycelia, whereas those lowly-pathogenic ones had white colonies, with sparse mycelia. Those with fast-growing colonies showed strong pathogenicity, while those with slowly-growing colonies displayed weak pathogenicity. There was no relationship between conidia yield and pathogenicity. The optimum temperature for the growth of C. gloeosporioides mycelia was 25-30 ℃, and the optimum pH was 5.0-7.0. C. gloeosporioides could make use of various carbon sources (monosaccharide and disaccharide), inorganic and organic nitrogen sources, and the optimal carbon source and nitrogen source were sucrose and beef extract, respectively. [Conclusion] Our study benefits further understanding of C. gloeospori-oides and helps to control pear anthracnose more effectively.展开更多
[Objective] This study was to investigate the relationship between biological characteristics of Beauveria bassiana (Bals.) Vuill and pathogenicity to Bombyx rnori L, with the aim to provide scientific basis for the...[Objective] This study was to investigate the relationship between biological characteristics of Beauveria bassiana (Bals.) Vuill and pathogenicity to Bombyx rnori L, with the aim to provide scientific basis for the control of white muscardine in Bombyx mori L. [Method] The strains isolated and purified from the 6 Beauveria bassiana biocontrol agents from all over the country and the 3 white muscardine silkworms collected from Guangxi provincial silkworm rearing areas were identified by the morphological observation and molecular biology technology. The pathogenicity of B. bassaina to silkworms was determined, and the biological characteristics such as growth diameter, sporulation and the extracellular protease activity of the different B. bassiana strains were compared. [Result] The isolated 9 strains were all B. bassaina (Bals.) Vuillemin, and all strains had high pathogenicity to silkworm, but with different pathogenicities. The growth diameter, sporulation and extracellular protease activity of different B. bassiana strains were also different, and showed correlation with the patheogenicity to silkworms. [Conclusion] B. bassiana spores production amount and exocellular protease activity had significant positive correlation with their pathogenicity to silkworm.展开更多
All known subtypes of influenza A viruses are maintained in wild waterfowl, the natural reservoir of these viruses. Influenza A viruses are isolated from a variety of animal species with varying morbidity and mortalit...All known subtypes of influenza A viruses are maintained in wild waterfowl, the natural reservoir of these viruses. Influenza A viruses are isolated from a variety of animal species with varying morbidity and mortality rates. More importantly, influenza A viruses cause respiratory disease in humans with potentially fatal outcome. Local or global outbreaks in humans are typically characterized by excess hospitalizations and deaths. In 1997, highly pathogenic avian influenza viruses of the H5N1 subtype emerged in Hong Kong that transmitted to humans, resulting in the first documented cases of human death by avian influenza virus infection. A new outbreak started in July 2003 in poultry in Vietnam, Indonesia, and Thailand, and highly pathogenic avian H5N1 influenza viruses have since spread throughout Asia and into Europe and Africa. These viruses continue to infect humans with a high mortality rate and cause worldwide concern of a looming pandemic. Moreover, H5N1 virus outbreaks have had devastating effects on the poultry industries throughout Asia. Since H5N1 virus outbreaks appear to originate from Southern China, we here examine H5N1 influenza viruses in China, with an emphasis on their biological properties.展开更多
The gastrointestinal tract harbors a large number and diverse array of commensal bacteria and is an important entry site for pathogens.For these reasons,the intestinal immune system is uniquely dedicated to protect ag...The gastrointestinal tract harbors a large number and diverse array of commensal bacteria and is an important entry site for pathogens.For these reasons,the intestinal immune system is uniquely dedicated to protect against infections,while avoiding the development of destructive inflammatory responses to the microbiota.Several models have been proposed to explain how the immune system discriminates between,and appropriately responds to,commensal and pathogenic microorganisms.Dendritic cells(DCs)and regulatory T cells(Treg)are instrumental in maintaining immune homeostasis and tolerance in the gut.DCs are virtually omnipresent and are remarkably plastic,having the ability to adapt to the influences of the microenvironment.Different DC populations with partially overlapping phenotypic and functional properties have been described in different anatomical locations.DCs in the draining mesenteric lymph nodes,in the intestinal lamina propria and in Peyer's patches partake both in the control of intestinal inflammation and in the maintenance of gut tolerance.In this respect,gutresident DCs and macrophages exert tolerogenic functions as they regularly encounter and sense commensal bacteria.In contrast,migrating DC subsets that are recruited to the gut as a result of pathogenic insults initiate immune responses.Importantly,tolerogenic DCs act by promoting the differentiation and expansion of Treg cells that efficiently modulate gut inflammation,as shown both in preclinical models of colitis and in patients with inflammatory bowel disease(IBD).This article reviews the phenotypic and functional features of gut DC subsets and discusses the current evidence underpinning the DC contribution to the pathogenesis of the major clinical subtypes of human IBD.It also addresses the potential clinical benefit derived from DC targeting either in vivo or in vitro.展开更多
In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the...In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the most hopeful system in these methods about bio-control. Controls of bacteriophage for each pathogen species and subspecies and determination of phage-host originality are important because efficient bio-control was achieved. Researches concentrated on some food-borne pathogen bacteria such as E. coli O157:H7, Campylobacter, Salmonella and Listeria. In a consequence of these studies made as in vitro and in vivo, first commercial production of phage which will be used in foods was made in Netherlands. Also, it has been informed that use of phage is cost-efficient alternative as compared with other preservatives. This review, discussed application of bacteriophages as bio-control agents in food and advantages and disadvantages about uses of bacteriophages by taking into account antimicrobial characteristics of them.展开更多
The strains ofLactobacillus delbrueckii subsp, lactis widely used in food preservation due to ability produce high amount of hydrogen peroxide at refrigerator temperatures to inhibit food-borne pathogens and psychroph...The strains ofLactobacillus delbrueckii subsp, lactis widely used in food preservation due to ability produce high amount of hydrogen peroxide at refrigerator temperatures to inhibit food-borne pathogens and psychrophilic spoilage microorganisms. In order to improve of bio-preservation efficacy ofL. delbrueckii MH 10 mutations causing resistance to streptomycin (str) were used. Among UV-mutagenized population of L. delbruecla'i three str mutants producing high amounts of H2O2 were selected. Sir mutants produced significant amounts of hydrogen peroxide 50-60 μg/ml in sodium phosphate buffer (0.2 M, pH 6.5) and in beef broth (BB) at 5 ℃ for 5 days submerged cultivation without of growth. Evaluation mutants antibacterialactivity at refrigeration temperatures against food-borne pathogen Escherichia coli O157:H7 revealed elimination of pathogen total number up to practically undetectable amount for 3 days. In case of solid-state cultivation on agar-based medium, disks soaked by mutant cells suspensions formed larger inhibitory zones on E. coli O157:H7 lawn for one-day cold exposition. The size of inhibition zone depends on concentration of LAB cells. Str mutants L. delbrueckii reduced initial amount 2 - 105 of E. coil O 157:H7 in ground beef up to 3 log for 3 days of solid-state cocultivation when the wild strain reduced only 2 log. The application ofL. delbrueckii mutants did not cause any changes in sensory characteristics of ground beef, moreover promotes expanding of shelf-life due to inhibition of psychrophilic spoilage microorganisms.展开更多
The study focused on analysis and evaluation of microbial contamination of raw beef was designed to (1) determine the presence of foodborne pathogens in raw beef; (2) compare the prevalence of microbial contaminat...The study focused on analysis and evaluation of microbial contamination of raw beef was designed to (1) determine the presence of foodborne pathogens in raw beef; (2) compare the prevalence of microbial contamination among the three supermarkets, and (3) evaluate the sanitary quality of raw beef products. Also, six kind of microorganisms including Total Plate Count, Total Coliform and Fecal Coliform, which represented sanitary quality and E. coli, S. Aureus and B. cereus, which determined the presence of foodborne pathogens, were analyzed. The procedures used to analyse experimental samples taken from three supermarket (in every one week for three weeks) in Phnom Penh were based on Merck's study in 2005. The results had shown that there were no significant differences in Total Plate Counts, Total Coliform and Fecal Coliform in all samples, and they were found in unacceptable numbers in the raw beef products. However, the prevalence of foodborne pathogens including E. coli, S. aureus and B. cereus were found in acceptable numbers. Furthermore, the samples taken from the second supermarket had the highest level of microbial contamination among the three supermarkets, while the samples taken from the first supermarket had the lowest level of microbial contamination. This experimental finding demonstrated the need for sanitary improvement in the beef retails markets and strict sanitary guideline and implementation of these practices could guarantee consumers' health by consuming raw beefs with the lowest risk of foodborne pathogens.展开更多
基金Supported by Special Project for Marine Fisheries Science and Technology and Industrial Development of Guangdong Province(A201508A05)Regional Demonstration Project of Marine Economy Innovation and Development of Guangdong Province(GD2012-A03-012)~~
文摘[Objective] The biological characteristics and pathogenicities of Shewanella algae and Shewanella abalone from Babylonia were studied in this paper. [Method]The hemolytic bacteria were isolated from the hepatopancreas of Babylonia suffered from proboscis edema with blood agar plate. The dominant bacterial community in the ill Babylonia was identified by 16 S r DNA sequence analysis, and the bacterial cultural and biochemical characteristics and pathogenicities were studied. [Result]The Shewanella bacteria, including Shewanella algae and Shewanella abalone, are the dominant bacterial community in Babylonia suffered from proboscis edema.The colony characteristics of Shewanella algae in nutrient agar medium, TCBS agar medium and CHROMagar vibrio colored medium were similar to those of Shewanella abalone. Shewanella algae possessed β-hemolysis and Shewanella abalone possessed α-hemolysis in the blood agar plate. The biochemical reaction of Shewanella algae and Shewanella abalone was all of non-fermentation type. The results of artificial infection test showed that half lethal dose(LD50) of the test strains of Shewanella algae was 10-5.50/0.1 ml. The test strains of Shewanella algae have strong toxicity, and could cause mice and chickens to die of sepsis with mortality of100%. The mortality of Babylonia infected with Shewanella algae was 10%; while the survived Babylonia lost the ability of moving and intaking for a long time, but they were not suffered from proboscis edema. There was no death in mice or chicks infected with Shewanella abalone, but their livers and spleens were slightly hyperemic and swelling. There was also no death in Babylonia infected with Shewanella abalone, but their intaking and moving ability was lost for a short time.[Conclusion] Although Shewanella algae and Shewanella abalone were the dominant bacteria in Babylonia suffered from proboscis edema, they were not the main pathogenic bacteria for proboscis edema. Shewanella algae had strong pathogenicity to mice, chicks and Babylonia, while Shewanella abalone showed no marked pathogenicity to those experimental animals in this study.
基金Supported by the Jiangsu Provincial Fund for Self-dependent Innovation of AgriculturalTechnology(CX10209)Special Fund for the Technology System Construction ofModern Pear Industry(nycytx-29-09)National"948"Project(2010-C18)~~
文摘[Objective] This study aimed to explore the biological characteristics of Col etotrichum gloeosporioides in pears. [Method] Twenty-five C. gloeosporioides strains were isolated and identified from the diseased samples. Their pathogenicity was identified by inoculating the surface of punctured pears with fungal discs. The effects of different temperatures, pH values, carbon sources and nitrogen sources on the growth of C. gloeosporioides mycelia were explored by incubating fungal discs on the center of plates. [Result] Among the twenty-five C. gloeosporioides strains, three had strong pathogenicity, and eighteen had intermediate pathogenicity, and four strains had weak pathogenicity. Those highly-pathogenic strains had darker colonies, with dense mycelia, whereas those lowly-pathogenic ones had white colonies, with sparse mycelia. Those with fast-growing colonies showed strong pathogenicity, while those with slowly-growing colonies displayed weak pathogenicity. There was no relationship between conidia yield and pathogenicity. The optimum temperature for the growth of C. gloeosporioides mycelia was 25-30 ℃, and the optimum pH was 5.0-7.0. C. gloeosporioides could make use of various carbon sources (monosaccharide and disaccharide), inorganic and organic nitrogen sources, and the optimal carbon source and nitrogen source were sucrose and beef extract, respectively. [Conclusion] Our study benefits further understanding of C. gloeospori-oides and helps to control pear anthracnose more effectively.
基金Supported by the Scientific Research and Technology Development Planning Program of Guangxi Province(10169-08)the Program for the Construction of Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection(Guikeneng1001Z014)~~
文摘[Objective] This study was to investigate the relationship between biological characteristics of Beauveria bassiana (Bals.) Vuill and pathogenicity to Bombyx rnori L, with the aim to provide scientific basis for the control of white muscardine in Bombyx mori L. [Method] The strains isolated and purified from the 6 Beauveria bassiana biocontrol agents from all over the country and the 3 white muscardine silkworms collected from Guangxi provincial silkworm rearing areas were identified by the morphological observation and molecular biology technology. The pathogenicity of B. bassaina to silkworms was determined, and the biological characteristics such as growth diameter, sporulation and the extracellular protease activity of the different B. bassiana strains were compared. [Result] The isolated 9 strains were all B. bassaina (Bals.) Vuillemin, and all strains had high pathogenicity to silkworm, but with different pathogenicities. The growth diameter, sporulation and extracellular protease activity of different B. bassiana strains were also different, and showed correlation with the patheogenicity to silkworms. [Conclusion] B. bassiana spores production amount and exocellular protease activity had significant positive correlation with their pathogenicity to silkworm.
基金Acknowledgments We thank Susan Watson for editing the manuscript and those in our laboratories who contributed to the data cited in this review. We also thank Ryo Takano for the preparation of figures. Research in HC's group is supported by the Ministry of Science and Technology, China (2004BA519A-57, 2006BAD06A05). Research in GFG's group is supported by the Ministry of Science and Technology, China (MOST, 2005CB523001 and 2006BAD06A01), the National Natural Science Foundation of China (NSFC, Grant #3059934, #30525010) and the US National Institutes of Health (U19 AI051915-05S1). Research in YS's group is supported by the Ministry of Science and Technology, China (MOST, 2005CB523006 and 2006BAD06A15), and the National Natural Science Foundation of China (NSFC, Grant #30599433). Research in YK's group is supported by National Institute of Allergy and Infectious Diseases Public Health Service research grants by CREST and ERATO (Japan Science and Technology Agency), and by grants-in-aid and a contract research fund for the Program of Founding Research Centers for Emerging and Reemerging Infectious Diseases from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.
文摘All known subtypes of influenza A viruses are maintained in wild waterfowl, the natural reservoir of these viruses. Influenza A viruses are isolated from a variety of animal species with varying morbidity and mortality rates. More importantly, influenza A viruses cause respiratory disease in humans with potentially fatal outcome. Local or global outbreaks in humans are typically characterized by excess hospitalizations and deaths. In 1997, highly pathogenic avian influenza viruses of the H5N1 subtype emerged in Hong Kong that transmitted to humans, resulting in the first documented cases of human death by avian influenza virus infection. A new outbreak started in July 2003 in poultry in Vietnam, Indonesia, and Thailand, and highly pathogenic avian H5N1 influenza viruses have since spread throughout Asia and into Europe and Africa. These viruses continue to infect humans with a high mortality rate and cause worldwide concern of a looming pandemic. Moreover, H5N1 virus outbreaks have had devastating effects on the poultry industries throughout Asia. Since H5N1 virus outbreaks appear to originate from Southern China, we here examine H5N1 influenza viruses in China, with an emphasis on their biological properties.
基金Supported by The "Stem Cell Project",Fondazione Roma,Italy and by the Associazione Italiana per la Ricerca sul Cancro,Milan,Italy(AIRC,Grant No.8556)
文摘The gastrointestinal tract harbors a large number and diverse array of commensal bacteria and is an important entry site for pathogens.For these reasons,the intestinal immune system is uniquely dedicated to protect against infections,while avoiding the development of destructive inflammatory responses to the microbiota.Several models have been proposed to explain how the immune system discriminates between,and appropriately responds to,commensal and pathogenic microorganisms.Dendritic cells(DCs)and regulatory T cells(Treg)are instrumental in maintaining immune homeostasis and tolerance in the gut.DCs are virtually omnipresent and are remarkably plastic,having the ability to adapt to the influences of the microenvironment.Different DC populations with partially overlapping phenotypic and functional properties have been described in different anatomical locations.DCs in the draining mesenteric lymph nodes,in the intestinal lamina propria and in Peyer's patches partake both in the control of intestinal inflammation and in the maintenance of gut tolerance.In this respect,gutresident DCs and macrophages exert tolerogenic functions as they regularly encounter and sense commensal bacteria.In contrast,migrating DC subsets that are recruited to the gut as a result of pathogenic insults initiate immune responses.Importantly,tolerogenic DCs act by promoting the differentiation and expansion of Treg cells that efficiently modulate gut inflammation,as shown both in preclinical models of colitis and in patients with inflammatory bowel disease(IBD).This article reviews the phenotypic and functional features of gut DC subsets and discusses the current evidence underpinning the DC contribution to the pathogenesis of the major clinical subtypes of human IBD.It also addresses the potential clinical benefit derived from DC targeting either in vivo or in vitro.
文摘In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the most hopeful system in these methods about bio-control. Controls of bacteriophage for each pathogen species and subspecies and determination of phage-host originality are important because efficient bio-control was achieved. Researches concentrated on some food-borne pathogen bacteria such as E. coli O157:H7, Campylobacter, Salmonella and Listeria. In a consequence of these studies made as in vitro and in vivo, first commercial production of phage which will be used in foods was made in Netherlands. Also, it has been informed that use of phage is cost-efficient alternative as compared with other preservatives. This review, discussed application of bacteriophages as bio-control agents in food and advantages and disadvantages about uses of bacteriophages by taking into account antimicrobial characteristics of them.
文摘The strains ofLactobacillus delbrueckii subsp, lactis widely used in food preservation due to ability produce high amount of hydrogen peroxide at refrigerator temperatures to inhibit food-borne pathogens and psychrophilic spoilage microorganisms. In order to improve of bio-preservation efficacy ofL. delbrueckii MH 10 mutations causing resistance to streptomycin (str) were used. Among UV-mutagenized population of L. delbruecla'i three str mutants producing high amounts of H2O2 were selected. Sir mutants produced significant amounts of hydrogen peroxide 50-60 μg/ml in sodium phosphate buffer (0.2 M, pH 6.5) and in beef broth (BB) at 5 ℃ for 5 days submerged cultivation without of growth. Evaluation mutants antibacterialactivity at refrigeration temperatures against food-borne pathogen Escherichia coli O157:H7 revealed elimination of pathogen total number up to practically undetectable amount for 3 days. In case of solid-state cultivation on agar-based medium, disks soaked by mutant cells suspensions formed larger inhibitory zones on E. coli O157:H7 lawn for one-day cold exposition. The size of inhibition zone depends on concentration of LAB cells. Str mutants L. delbrueckii reduced initial amount 2 - 105 of E. coil O 157:H7 in ground beef up to 3 log for 3 days of solid-state cocultivation when the wild strain reduced only 2 log. The application ofL. delbrueckii mutants did not cause any changes in sensory characteristics of ground beef, moreover promotes expanding of shelf-life due to inhibition of psychrophilic spoilage microorganisms.
文摘The study focused on analysis and evaluation of microbial contamination of raw beef was designed to (1) determine the presence of foodborne pathogens in raw beef; (2) compare the prevalence of microbial contamination among the three supermarkets, and (3) evaluate the sanitary quality of raw beef products. Also, six kind of microorganisms including Total Plate Count, Total Coliform and Fecal Coliform, which represented sanitary quality and E. coli, S. Aureus and B. cereus, which determined the presence of foodborne pathogens, were analyzed. The procedures used to analyse experimental samples taken from three supermarket (in every one week for three weeks) in Phnom Penh were based on Merck's study in 2005. The results had shown that there were no significant differences in Total Plate Counts, Total Coliform and Fecal Coliform in all samples, and they were found in unacceptable numbers in the raw beef products. However, the prevalence of foodborne pathogens including E. coli, S. aureus and B. cereus were found in acceptable numbers. Furthermore, the samples taken from the second supermarket had the highest level of microbial contamination among the three supermarkets, while the samples taken from the first supermarket had the lowest level of microbial contamination. This experimental finding demonstrated the need for sanitary improvement in the beef retails markets and strict sanitary guideline and implementation of these practices could guarantee consumers' health by consuming raw beefs with the lowest risk of foodborne pathogens.