基因芯片法在食源性疾病中诊断效果及影响多因素Logistic分析研究

目的对比基因芯片法在食源性疾病诊断中的效果,并对影响多因素进行logistic分析。方法选择180例临床表现符合食源性疾病诊断标准的患者作为研究对象,随机均分为实验组和对照组各90例,对照组采用传统的常规培养检测方法,实验组采用基因芯片法进行检测,对比2种方法的检出率、检测耗时以及检测灵敏度。结果实验组的检出率和检测灵敏度均高于对照组的检出率和检测灵敏度,对照组的检测耗时大约是实验组检测耗时的8.24倍。结论相比常规方法,应用基因芯片法的诊断速度更快、准确率更高,在诊断食源性疾病中的应用效果更佳。通过对单因素的χ~2和t检验,确定对食源性疾病有直接影响的多个因素。对影响食源性疾病的多个因素进行Logistic分析,分析结果表明在本次研究分析中,影响较大的因素是人们的饮食卫生以及进食规律。     

A set of software components for the simulation of plant airborne diseases

Models to evaluate the impact of plant diseases on crop production under current and future climatic conditions are increasingly requested by different stakeholders. This paper presents four software components – InoculumPressure, DiseaseProgress, ImpactsOnPlants, AgromanagementDisease – which implement models to simulate the dynamics of generic polycyclic fungal epidemics and interactions with crop physiological processes. The software architecture adopted allows extending the components with alternate approaches to reproduce specific pathosystems or compare predictive capabilities. As proofs of concept, (i) the components are coupled with two crop simulators to reproduce wheat brown rust and rice blast epidemics and their impacts on leaf area and yield formation; (ii) spatially distributed sensitivity analyses are performed for rice in China and wheat in Europe to investigate model behaviour; (iii) a preliminary evaluation against observations of rice blast severity is performed in Northern Italy. The components are explicitly targeted to the modelling of crop–pathogen interactions to perform scenario analysis.     

Inactivation of foodborne pathogens on the surfaces of different packaging materials using low-pressure air plasma

In the present study, low-pressure glow discharge plasma was used for surface decontamination of the common food packaging materials, namely glass, polyethylene, polypropylene, nylon, and paper foil. Low-pressure air plasma was generated over a vacuum pressure range of 0.5–5.0 Torr, and at a power density range of 12.4–54.1 mW/cm³. Compared to plasma-unexposed surfaces, no significant changes in optical properties, color characteristics, surface temperatures, tensile strengths, and deformation strains were observed with plasma-exposed surfaces. On plasma exposure of food pathogens-loaded packaging materials surfaces, as high as 4-log reduction (99.99%) in viable cell counts of tested food pathogens, especially Escherichia coli O157:H7 and Staphylococcus aureus, was observed within 5 min. And, the pathogens inactivation pattern can be better explained by Singh-Heldman model. Therefore, low-pressure air plasma was shown to be effective for inactivation of major foodborne pathogens, and different food packaging materials can be decontaminated using the plasma without adversely affecting their physical properties.     

Metabolites produced during the growth of probiotics in cocoa supplementation and the limited role of cocoa in host-enteric bacterial pathogen interactions

Cocoa contains various compounds that can significantly affect the growth of a broad range of bacteria, and have multiple human health-promoting properties. In this study, the effects of cocoa powder on the growth of Lactobacillus, common milk resident bacteria, and three major foodborne enteric bacterial pathogens; enterohemorrhagic Escherichia coli O157:H7 (EHEC), Salmonella enterica serovar Typhimurium, and Listeria monocytogenes, were investigated in vitro. Significant (p < 0.05) growth stimulation on beneficial bacteria including Lactobacillus and other resident bacteria in milk was observed in the presence of 3% cocoa powder. In contrast, growth of three foodborne enteric pathogens was significantly (p < 0.05) inhibited within 9 h, but no stimulation was found with longer incubation. In addition, cocoa powder significantly (p < 0.05) inhibited adhesion to and invasion of INT407 cells by these bacterial pathogens in a dose dependent manner. These results suggest that addition of cocoa into dairy products could improve the beneficial effect of probiotics by stimulating their growth, without raising the risk of cross-contamination with enteric pathogens.     

Engineering Sensor Arrays Using Aggregation‐Induced Emission Luminogens for Pathogen Identification

Lacking rapid and reliable pathogen diagnostic platforms, inadequate or delayed antimicrobial therapy could be made, which greatly threatens human life and accelerates the emergence of antibiotic‐resistant pathogens. In this contribution, a series of simple and reliable sensor arrays based on tetraphenylethylene (TPE) derivatives are successfully developed for detection and discrimination of pathogens. Each sensor array consists of three TPE‐based aggregation‐induced emission luminogens (AIEgens) that bear cationic ammonium group and different hydrophobic substitutions, providing tunable logP (n‐octanol/water partition coefficient) values to enable the different multivalent interactions with pathogens. On the basis of the distinctive fluorescence response produced by the diverse interaction of AIEgens with pathogens, these sensor arrays can identify different kinds of pathogens, even normal and drug‐resistant bacteria, with nearly 100% accuracy. Furthermore, blends of pathogens can also be identified accurately. The sensor arrays exhibit rapid response (about 0.5 h), high‐throughput, and easy‐to‐operate without washing steps.     

1株桃果实采后病原真菌的鉴定以及碳源代谢指纹图谱分析

从采后贮藏过程中发病的八月脆桃果实（Amygdalus persica cv.Bayuecui）中分离到1株真菌菌株074#.通过对病原菌形态学观察以及核糖体ITS rDNA序列分析,证明菌株074#为灰葡萄孢霉菌（Botrytis elliptica）.致病性试验结果表明,桃果实为灰葡萄孢霉菌的寄主.通过Biolog FFMicroPlate分析该病原菌对95种碳源的利用能力,结果表明,Botrytis elliptica代谢指纹图谱为最适碳源包括D-果糖、蔗糖、L-苹果酸、琥珀酸、D-葡萄糖酸、L-天门冬氨酸、L-丝氨酸、腺苷、5＇-磷酸腺苷等26种,可利用碳源14种,不可利用碳源55种.     

Functionalized Graphene as Extracellular Matrix Mimics: Toward Well‐Defined 2D Nanomaterials for Multivalent Virus Interactions

Polysulfated nanomaterials that mimic the extracellular cell matrix are of great interest for their potential to modulate cellular responses and to bind and neutralize pathogens. However, control over the density of active functional groups on such biomimetics is essential for efficient interactions, and this remains a challenge. In this regard, producing polysulfated graphene derivatives with control over their functionality is an intriguing accomplishment in order to obtain highly effective 2D platforms for pathogen interactions. Here, a facile and efficient method for the controlled attachment of a heparin sulfate mimic on the surface of graphene is reported. Dichlorotriazine groups are conjugated to the surface of graphene by a one‐pot [2+1] nitrene cycloaddition reaction at ambient conditions, providing derivatives with defined functionality. Consecutive step by step conjugation of hyperbranched polyglycerol to the dichlorotriazine groups and eventual conversion to the polyglycerol sulfate result in the graphene based heparin biomimetics. Scanning force microscopy, cryo‐transmission electron microscopy, and in vitro bioassays reveal strong interactions between the functionalized graphene (thoroughly covered by a sulfated polymer) and vesicular stomatitis virus. Infection experiments with highly sulfated versions of graphene drastically promote the infection process, leading to higher viral titers compared to nonsulfated analogues.     

Two-photon luminescence imaging of Bacillus spores using peptide-functionalized gold nanorods

Bacillus subtilis spores (a simulant of Bacillus anthracis) have been imaged by two-photon luminescence (TPL) microscopy, using gold nanorods (GNRs) functionalized with a cysteine-terminated homing peptide. Control experiments using a peptide with a scrambled amino acid sequence confirmed that the GNR targeting was highly selective for the spore surfaces. The high sensitivity of TPL combined with the high affinity of the peptide labels enables spores to be detected with high fidelity using GNRs at femtomolar concentrations. It was also determined that GNRs are capable of significant TPL output even when irradiated at near infrared (NIR) wavelengths far from their longitudinal plasmon resonance (LPR), permitting considerable flexibility in the choice of GNR aspect ratio or excitation wavelength for TPL imaging.      

Prevalence and antimicrobial resistance of Campylobacter species isolated from the avian eggs

Campylobacter is one of the most important food borne pathogens that cause bacterial gastroenteritis worldwide. The most commonly isolated species in humans are Campylobacter jejuni (C. jejuni) and Campylobacter coli. The emergence of antimicrobial resistance in Campylobacter spp. has been a growing public health concern globally. Information about antimicrobial resistance of Campylobacter at different levels of production is important for the development of control strategies for this pathogen. This study was conducted to determine the prevalence and antimicrobial resistance of Campylobacter spp. isolated from different eggs from different avian species in Iran. A total of 440 egg samples were collected from different avian and analyzed for the presence of Campylobacter spp. in eggshell and eggs content under sterile conditions using Campylobacter selective agar base and the species were identified by biochemical tests. The suspected colonies were subjected to PCR assay for final confirmation as Campylobacter spp., and identification of C. jejuni or Campylobacter coli. Antimicrobial susceptibility testing was performed by the Kirby–Bauer disk diffusion method using Mueller Hinton agar. Campylobacters were detected in a total of 7 out of 100 (7%) eggshell of chicken samples and in 3 out of 60 (5%) eggshell of duck samples. In addition, Campylobacter spp. were also detected in 3.3%, 2.5%, 4.2%, 5% and 3.8 of the eggshell of goose, ostrich, partridge, quail and turkey samples, respectively. The overall prevalence rate of Campylobacter species from different avian eggs was found to be 7.7% (34/440). Among different avian egg samples, Campylobacter jejuni was more frequently isolated 28 (n = 28, 6.3%) than C. coli 6 (n = 6, 1.3%). In addition, the prevalence of C. jejuni was highest in summer and lowest in autumn. In this study Campylobacter spp. showed significant difference in resistance pattern with tetracycline and ciprofloxacin but gentamicin resistance was not found in both C. coli and C. jejuni isolates. Therefore, gentamicin is safe and effective drugs for the treatment of human campylobacteriosis if avian egg is considered as the source of infection.     

Behaviour of food-borne pathogens on dry cured sausage manufactured with herbs and spices essential oils and their sensorial acceptability

Dry cured sausages such as Portuguese chouriço de vinho are made generally with roughly minced pork and fat and seasoned with a large variety of herbs and spices. It is a particular sausage because meat is marinated in wine with other seasonings during 24–48 h before stuffing. Nowadays, health concerns of consumers have left food processors with less flexibility to choose preservative substances and methods. Thus, the objective of this study was to assess the antimicrobial effect of essential oils (EOs) of herbs and spices traditionally used in seasoning dry cured sausage chouriço against Salmonella spp., Listeria monocytogenes and Staphylococcus aureus. First, antibacterial activity of 14 EOs was screened by disk diffusion assay. Those EOs that displayed antimicrobial activity were further characterized by GC–MS and added as natural antimicrobial substances to the manufacture of chouriço at two concentrations (0.005% and 0.05%). Samples were analyzed 24 h after the preparation of the batter and after 3, 8, 15 and 21 days.After 15 days of drying, Salmonella spp. and L. monocytogenes counts decreased by ca. 2 log cfu/g in all samples. At 3 days, Salmonella spp. was already undetectable in chouriço made with 0.05% of garlic and oregano EOs. Both Salmonella spp. and L. monocytogenes were not detected after 8 and 15 days of drying respectively. S. aureus was still presented after 21 days of drying although its counts were not high enough to a potential enterotoxins presence. Utilization of EOs in manufacture of dry cured sausage resulted in an interesting strategy to improve its safety against Salmonella spp, L. monocytogenes and S. aureus, but with sensory limitations, that does not allow its use in high concentrations, that are those more interesting for pathogen inhibition.However, results with good potential to be applied by the industry were found, once the level of addition of 0.005% contributed for significant reductions on the pathogen's counts and for a shorter period to achieve the not detectable level, allowing the industry to shorten the drying period and, thereafter increasing yield production.