幽门螺杆菌的致病物质及其致病性

幽门螺杆菌(HP)籍螺旋状结构和特别鞭毛运动穿过胃粘膜表面粘液,经粘附因子与上皮细胞结合。HP产生大量尿素酶,有助于其抵抗胃酸,在胃内生存,并通过分解尿素产氨损伤细胞。HP分泌磷脂酶A和C削弱细胞膜磷脂双层结构。宿主的免疫反应在致病过程中也有一定作用。

食源性生物致病物所致疾病的危险评估规则

食源性生物致病物所致疾病的危险评估规则ＢｕｃｈａｎａｎＲＬ在美国国家科学院的建议下，１９８８年成立了国家食品微生物标准咨询委员会（ＮＡＣＭＣＦ），用以解答农业部、卫生和人类服务部、国防部及贸易部提出的有关食品微生物安全的问题。该委员会受农业部的领导和...

Isolation and Identification of Colletotrichum gloeosporioides in Pears and Its Biological Characteristics

[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.

Biological Characteristics and Pathogenicities of Shewanella algae and Shewanella abalone from Babylonia

[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.

Detection and Sequence Analysis of Escherichia coli Virulence Genes

[Objective] This study aimed to explore the pathogenic mechanism of E., cherichia coll. [Method] An E. coil strain isolated from raccoon dogs in vivo was studied, which had been identified, PCR was used to detect the gene of irp2 （301 bp） and fyuA （953 bp） related to E. coil virulence and PCR products were s, quenced. [Result] The genes of irp2 and fyuA were successfully amplified in boi strains isolated from raccoon dogs. Compared with the GenBank, the identity of tTr irp2 gene sequence and the fyuA gene sequence of the strain reached 98.5% 99.2% and 98.9%-100% respectively. Compared with each other, the identity of tt- two gene sequences of irp2 was 99.3%, and that between the two fyuA gene se quences was 98.9%. [Conclusion] This study provided scientific experimental data fi E. coil pathogenicity, prevention, diagnosis and treatment.

甲状腺肿病因学的研究概况

碘缺乏是地方性甲状腺肿(地甲肿)的主要病因,已为大量的流行病学调查资料和实验结果所证实,并被广泛接受。但人们在研究地甲肿病因过程中,发现碘缺乏并不是唯一的因素,也不能完全用以解释全部病因学问题。例如有的地区缺碘严重。

探讨老年肺炎患者临床诊断中检验血清C反应蛋白(CRP)、血沉(ESR)、以及D-二聚体(D-D)水平的临床价值

目的探讨老年肺炎患者临床诊断中检验血清C反应蛋白(CRP)、血沉(ESR)、以及D-二聚体(D-D)水平的临床价值。方法随机选择该院2015年1月—2016年12月期间收治的50例老年肺炎病例为观察组研究对象,并以同期自愿参与研究的50名健康老年体检者为对照组研究对象,比较两组血清C反应蛋白(CRP)、血沉(ESR)、以及D-二聚体(D-D)水平。结果观察组老年患者血清CRP(103.2±23.4)mg/L、ESR(35.8±6.5)μg/L、D-D(1 152.4±43.1)mm/h水平均显著高于对照组(8.9±1.2)mg/L、(10.2±1.4)μg/L、(182.6±14.8)mm/h,差异有统计学意义(P<0.05)。将观察组以80岁为临界值分组,80岁以上患者CRP(102.4±21.8)mg/L、ESR(34.8±5.8)μg/L、D-D(1 148.7±45.2)mm/h与80岁以下患者(103.8±22.1)mg/L、(35.4±6.2)μg/L、(1 142.3±43.9)mm/h,差异无统计学意义(P>0.05)。结论临床上可行血清C反应蛋白、血沉及D-二聚体检测来诊断老年肺炎的情况,为治疗和预后提供有效依据。

卫生巾，小事情中有学问

经期用品的清洁卫生特别重要。因为，盆腔、子宫、宫颈、阴道、体外环境都是相通的，这样的结构使女性的生殖系统特别容易遭受外界致病物的侵袭，尤其月经期间，生殖器官的抵抗力下降，比平时更加脆弱，如果使用了不合标准的卫生巾，特别容易发生感染。

Relationship between Biological Characteristics of Beauveria bassiana (Bals.) Vuill and Pathogenicity to Bombyx mori L.

[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.

Fluorescent co-localization of PTS1 and PTS2 and its application in analysis of the gene function and the peroxisomal dynamic in Magnaporthe oryzae

The peroxisomal matrix proteins involved in many important biological metabolism pathways in eukaryotic cells are encoded by nucleal genes, synthesized in the cytoplasm and then transported into the organelles. Targeting and import of these proteins depend on their two peroxisomal targeting signals （PTS 1 and PTS2） in sequence as we have known so far. The vectors of the fluorescent fusions with PTS, i.e., green fluorescence protein （GFP）-PTS1, GFP-PTS2 and red fluorescence protein （RFP）-PTS1, were constructed and introduced into Magnaporthe oryzae Guy ll cells. Transformants containing these fusions emitted fluorescence in a punctate pattern, and the locations of the red and green fluorescence overlapped exactly in RFP-PTS 1 and GFP-PTS2 co-transformed strains. These data indicated that both PTS1 and PTS2 fusions were imported into peroxisomes. A probable higher efficiency of PTS1 machinery was revealed by comparing the fluorescence backgrotmds in GFP-PTS1 and GFP-PTS2 transformants. By introducing both RFP-PTS1 and GFP-PTS2 into Amgpex6 mutants, the involvement of MGPEX6 gene in both PTS1 and PTS2 pathways was proved. In addition, using these transformants, the inducement ofperoxisomes and the dynamic of peroxisomal number during the pre-penetration processes were investigated as well. In summary, by the localization and co-localization of PTS1 and PTS2, we provided a useful tool to evaluate the biological roles of the peroxisomes and the related genes.

Intestinal dendritic cells in the pathogenesis of inflammatory bowel disease

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.

Functional genomics in the rice blast fungus to unravel the fungal pathogenicity

A rapidly growing number of successful genome sequencing projects in plant pathogenic fungi greatly increase the demands for tools and methodologies to study fungal pathogenicity at genomic scale. Magnaporthe oryzae is an economically important plant pathogenic fungus whose genome is fully sequenced. Recently we have reported the development and application of functional genomics platform technologies in M. oryzae. This model approach would have many practical ramifications in design and implementation of upcoming functional genomics studies of filamentous fungi aimed at understanding fungal pathogenicity.

Successful treatment of giant rectal varices by modified percutaneous transhepatic obliteration with sclerosant:Report of a case

We present a female patient with continuous melena, diagnosed with rectal variceal bleeding. She had a history of esophageal varices, which were treated with endoscopic therapy. Five years after the treatment of esophageal varices, continuous melena occurred. Since colonoscopy showed that the melena was caused by giant rectal varices, we thought that they were not suitable to receive endoscopic treatment. We chose the modified percutaneous transhepatic obliteration with sclerosant, which is one of the interventional radiology techniques but a new clinical procedure for rectal varices. After the patient received this therapy, her condition of rectal varices was markedly improved.

Toxic hepatitis in occupational exposure to solvents

The liver is the main organ responsible for the metabolism of drugs and toxic chemicals, and so is the primary target organ for many organic solvents. Work activities with hepatotoxins exposures are numerous and, moreover, organic solvents are used in various industrial processes. Organic solvents used in different industrial processes may be associated with hepatotoxicity. Several factors contribute to liver toxicity; among these are: species differences, nutritional condition, genetic factors, interaction with medications in use, alcohol abuse and interaction, and age. This review addresses the mechanisms of hepatotoxicity. The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are: inflammation, dysfunction of cytochrome P450, mitochondrial dysfunction and oxidative stress. The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work.

Screening of marine fungus from Nanji Island and activity of their metabolites against pathogenic Vibrio from Pseudosciaena crocea

Seventy-eight marine fungal strains were isolated from sediment samples collected off the coast of Nanji Island, Wenzhou, Zhejiang Province, China. Antibacterial screening using the agar disc method showed that 19 of the isolated strains could inhibit at least one pathogenic Vibrio from Pseudosciaena crocea. Subsequent screening confirmed that nine strains produced antibacterial metabolites that had activity against one or several types of pathogenic Vibrio. Strain NJ0104 had the widest antimicrobial spectrum and strong activity, particularly against Fibrio parahaemolyticus-MM0810072. A preliminary study of N J0104 antibacterial metabolites demonstrated that they had thermal stability up to 80℃, ultraviolet stability up to 40 min and pH stability between 4.0-7.0. In addition, the antibacterial metabolites were readily soluble in butanol. To identify the specific strain, the ITS-5.8S rDNA regions of NJ0104 were PCR amplified and sequenced. Based on the combination of phenotypic and genotypic data, the strain was identified as Arthrinium sp.

H5N1 influenza viruses： outbreaks and biological properties

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.

Comparison and Evaluation of Three Animal Models for Studyingthe Pathogenicity of Staphylococcus epidermidis

In order to compare and evaluate three animal models for studying the pathogenicity of Staphylococcus epidermidis strains, three experimental animal models, namely, murine intra-venous LD 50, mouse foreign body infection and rat central venous catheter (CVC) infection models were used to assess the relative virulence of two S. epidermidis strains, ATCC 12228 and 97-337. The results from three animal models were comparable, indicating S.epidermidis 97-337 was more virulent than strain ATCC 12228. The rat CVC infection model best mimicked the conditions of clinical patients with intra-venous catheters, and more information could be obtained from this model. We conclude that different in vivo models serve for different purposes, and the rat CVC infection model is most suitable for studying specific characteristics of catheter related infections caused by S. epidermidis strains.

The Use of Str Mutations for Enhancement of Hydrogen Peroxide Formation by Lactobacillus Delbrueckii MH-IO at Refrigeration

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.

Effect of the Concentration of Spirulina platensis on the Growth of Bifidobacterium breve

The aim of this study is to demonstrate the influence of Spirulina platensis on the growth of Bifidobacteium breve in the infantile milk. The authors used a stump of Bifidobacterium breve isolated from the new saddles which was born after identification and characterization. The follow-up of the kinetics of growth of B. breve in the milk enriched by various concentrations of Spirulina （0, 1, 5 and 10 mg/mL） was realized, and the authors estimated the antimicrobial effect of the cultures realised on three pathogenic bacteria： a bacteria isolated from saddles ＂Salmonella ssp.＂, two reference stumps ＂Staphylococcus aureus ATCC25923＂ and ＂Escherichia coli ATCC25922＂. The growth rate was 0.11 hl for the culture of B. breve associated with Spirulina （10 mg/mL）, 0.09 hl for the culture of B. breve enriched with Spirulina （5 mg/mL） and 0.08 hl for the culture of B. breve enriched with Spirulina （1 mg/mL）. In the case of the pure culture of B. breve, the growth rate was 0.07 h1. The authors observed inhibitory effects of B. breve in the various cultures towards the considered pathogenic bacteria. The optimal antimicrobial activity was observed in the preculture bifid with the algae culture （10 mg/mL） towards Salmonella ssp. （Zi = 25 mm）, S. aureus ATCC25923 （Zi = 26 mm） and E. coli ATCC25922 （Zi = 28 mm）.