Search results for " microbial"
showing 10 items of 340 documents
pilF polymorphism-based real-time PCR to distinguish Vibrio vulnificus strains of human health relevance
2012
The Gram-negative bacterium Vibrio vulnificus is a common inhabitant of estuarine environments. Globally, V. vulnificus is a significant foodborne pathogen capable of causing necrotizing wound infections and primary septicemia, and is a leading cause of seafood-related mortality. Unfortunately, molecular methods for the detection and enumeration of pathogenic V. vulnificus are hampered by the genetically diverse nature of this pathogen, the range of different biotypes capable of infecting humans and aquatic animals, and the fact that V. vulnificus contains pathogenic as well as non-pathogenic variants. Here we report an alternative approach utilizing the development of a real-time PCR assay…
Development of a real-time PCR assay for detection and quantification of enterotoxigenic members of Bacillus cereus group in food samples
2009
A highly sensitive real-time PCR (qPCR) procedure, targeting the phosphatidylcholine-specific phospholipase C gene (pc-plc), was developed for specific detection and quantification of strains belonging to Bacillus cereus group. The target region was selected based on the enterotoxigenic profiles of 75 Bacillus strains. The inclusivity and exclusivity of the RTi-PCR assay were assessed with 59 isolates of the B. cereus group, 16 other Bacillus spp., and 4 non-Bacillus strains. The assay was also used to construct calibration curves for different food matrices, and it had a wide quantification range of 6 log units using both serial dilutions of purified DNA and calibrated cell suspensions of …
PCR-based procedures for detection and quantification of Staphylococcus aureus and their application in food.
2006
Aims: To evaluate the specificity of nuc targeted primers for PCR detection of Staphylococcus aureus in different food matrices and to establish a RTQ-PCR procedure suitable for the routine detection and quantification of this pathogen in food. Methods and Results: Specificity of nuc targeted primers (Pri1–Pri2 and the newly designed RTQ-PCR primers) was tested on a total of 157 strains of genetically confirmed identity, including reference and food isolates. PCR detection on artificially inoculated beef samples by DNA extraction using a DNeasy Tissue Kit (Qiagen GmhH, Hilden, Germany) showed a sensitivity value around 103 CFU g−1. The two RTQ-PCR systems, incorporating SYBR-Green I and T…
Real-time quantitative PCR of Staphylococcus aureus and application in restaurant meals.
2006
Staphylococcus aureus is considered the second most common pathogen to cause outbreaks of food poisoning, exceeded only by Campylobacter. Consumption of foods containing this microorganism is often identified as the cause of illness. In this study, a rapid, reliable, and sensitive real-time quantitative PCR was developed and compared with conventional culture methods. Real-time quantitative PCR was carried out by purifying DNA extracts of S. aureus with a Staphylococcus sample preparation kit and quantifying it in the LightCycler system with hybridization probes. The assay was linear from a range of 10 to 10(6) S. aureus cells (r2 > 0.997). The PCR reaction presented an efficiency of >85%. …
Comparison of Four Commercial DNA Extraction Kits for PCR Detection of Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Staphylococc…
2008
Four commercial DNA extraction methods, PrepMan Ultra (Applied Biosystems), InstaGene Matrix (BioRad), DNeasy Tissue kit (Qiagen), and UltraClean (MoBio), were tested for PCR detection of Listeria monocytogenes, Escherichia coli O157: H7, Salmonella, and Staphylococcus aureus in fresh, minimally processed vegetables. For comparative purposes, sensitivity assays with specific PCRs were carried out after DNA extraction with the four methods in green pepper, broccoli, and onion artificially inoculated with the four pathogens separately. As confirmed by statistical analysis, the DNeasy Tissue kit rendered the highest sensitivity values in the three matrices assayed for Salmonella, L. monocytoge…
Isolation of methanotrophic bacteria from termite gut.
2015
The guts of termites feature suitable conditions for methane oxidizing bacteria (MOB) with their permanent production of CH4 and constant supply of O2 via tracheae. In this study, we have isolated MOB from the gut contents of the termites Incisitermes marginipennis, Mastotermes darwiniensis, and Neotermes castaneus for the first time. The existence of MOB was indicated by detecting pmoA, the gene for the particulate methane monooxygenase, in the DNA of gut contents. Fluorescence in situ hybridization and quantitative real-time polymerase chain reaction supported those findings. The MOB cell titer was determined to be 10(2)-10(3) per gut. Analyses of the 16S rDNA from isolates indicated clos…
The human p53 gene mutated at position 249per se is not sufficient to immortalize human liver cells
1999
A particular point mutation of the tumor suppressor gene p53, namely a G→T transversion at the third base of codon 249, is frequently detected in primary hepatocellular carcinomas from patients living in areas where the levels of dietary exposure to aflatoxin B 1 and the rates of infection with the hepatitis B virus are very high. Very recently, a nontumorigenic liver epithelial cell line (HACL-1) with a finite life-span and expressing a number of hepatocyte-specific markers was established from a human hepatocellular adenoma in our laboratory. To analyze the role of mutated p53 in the immortalization of human liver cells, we transfected HACL-1 cells with an expression vector containing a h…
Arbuscular mycorrhizal fungi influence host infection during epidemics in a wild plant pathosystem
2022
SummaryWhile pathogenic and mutualistic microbes are ubiquitous across ecosystems and often co-occur within hosts, how they interact to determine patterns of disease in genetically diverse wild populations is unknown.To test whether microbial mutualists provide protection against pathogens, and whether this varies among host genotypes, we conducted a field experiment in three naturally-occurring epidemics of a fungal pathogen, Podosphaera plantaginis, infecting a host plant, Plantago lanceolata, in the Åland Islands, Finland. In each population, we collected epidemiological data on experimental plants from six allopatric populations that had been inoculated with a mixture of mutualistic arb…
Soil microbial biomass carbon and fatty acid composition of earthworm Lumbricus rubellus after exposure to engineered nanoparticles
2014
none 6 no First Online: 14 October 2014 The aim of this work was to investigate the effect of engineered nanoparticles (NPs) on soil microbial biomass C (MBC) and on earthworm Lumbricus rubellus. An artificial soil was incubated for 4 weeks with earthworms fed with vegetable residues contaminated by NPs, consisting of Ag, Co, Ni and TiO2. After the treatments, soils were analysed for MBC and total and water soluble metal-NPs, whereas earthworms were purged for 28 days and then analysed for fatty acids (FAs) and total metal-NPs. Longitudinal sections of earthworms were investigated by environmental scanning electron microscopy (ESEM), equipped with energy-dispersive X-ray spectroscopy (EDS),…
Italian multicenter study on infection hazards during dental practice: Control of environmental microbial contamination in public dental surgeries
2008
Abstract Background The present study assessed microbial contamination in Italian dental surgeries. Methods An evaluation of water, air and surface microbial contamination in 102 dental units was carried out in eight Italian cities. Results The findings showed water microbial contamination in all the dental surgeries; the proportion of water samples with microbial levels above those recommended decreased during working. With regard to Legionella spp., the proportion of positive samples was 33.3%. During work activity, the index of microbial air contamination (IMA) increased. The level of microbial accumulation on examined surfaces did not change over time. Conclusion These findings confirm …