from Luca Cocolin and Kalliopi Rantsiou writing in Quantitative Real-time PCR in Applied Microbiology:
Since its first application in food microbiology in the late '90s, quantitative PCR (qPCR) has attracted the interest of researchers, working mainly in the field of food safety, but lately also of microbiologists studying spoilage and fermentation processes. In addition to the advantages that conventional PCR offers in microbiological testing, i.e. specificity, reduced time of analysis and detection of viable but not culturable cells, qPCR allows quantification of target populations. This aspect is particularly relevant for foodborne pathogens, for which specific microbiological criteria exist, but also for spoilage and technological important microorganisms, in order to follow their population kinetics in foods. Although advancements in food microbiology have been made from its application, qPCR has not yet been utilized to its full potential: the quantification step is only rarely carried out and qPCR is often used as an alternative of conventional PCR. In this chapter authors will critically describe the application of qPCR in food microbiology based on the available literature, taking into account the specific problems and suggesting some possible solutions.
Showing posts with label microbiology. Show all posts
Showing posts with label microbiology. Show all posts
Predicting Disease Transmission from Geo-Tagged Micro-Blog Data
Researchers have begun to mine social network data in order to predict a variety of social, economic, and health related phenomena. While previous work has focused on predict- ing aggregate properties, such as the prevalence of seasonal influenza in a given country, researchers consider the task of fine- grained prediction of the health of specific people from noisy and incomplete data.
Antisense RNA that affects Rhodopseudomonas palustris quorum-sensingsignal receptor expression
Quorum sensing in the bacterium Rhodopseudomonas palustris involves the RpaI signal synthase, which produces p-coumaroyl-homoserine lactone (pC-HSL) and RpaR, which is a pC-HSL–dependent transcriptional activator. There is also an antisense rpaR transcript (asrpaR) of unknown function. Recent RNAseq studies have revealed that bacterial antisense RNAs are abundant, but little is known about the function of these molecules.
Role of Specific Quorum-Sensing Signals in the Regulation of Exopolysaccharide II Production within Sinorhizobium meliloti Spreading Colonies
Quorum sensing (QS) in Sinorhizobium meliloti involves at least half a dozen different N-acyl homoserine lactone (AHL) signals. These signals are produced by SinI, the sole AHL synthase in S. meliloti Rm8530. The sinI gene is regulated by two LuxR-type transcriptional regulators, SinR and ExpR. Mutations in sinI, sinR and expR abolish the production of exopolysaccharide II (EPS II).
Direct sampling of cystic fibrosis lungs indicates that DNA-based analyses of upper-airway specimens can misrepresent lung microbiota
Recent work using culture-independent methods suggests that the lungs of cystic fibrosis (CF) patients harbor a vast array of bacteria not conventionally implicated in CF lung disease. However, sampling lung secretions in living subjects requires that expectorated specimens or collection devices pass through the oropharynx.
Factors associated with the diversification of the gut microbial communities within chimpanzees from Gombe National Park
The gastrointestinal tract harbors large and diverse populations of bacteria that vary among individuals and within individuals over time. Numerous internal and external factors can influence the contents of these microbial communities, including diet, geography, physiology, and the extent of contact among hosts. To investigate the contributions of such factors to the variation and changes in gut microbial communities, authors analyzed the distal gut microbiota of individual chimpanzees from two communities in Gombe National Park, Tanzania.
Novel Virostatic Agents against Bluetongue Virus
Bluetongue virus (BTV), a member in the family Reoviridae, is a re-emerging animal disease infecting cattle and sheep. With its recent outbreaks in Europe, there is a pressing need for efficacious antivirals. Authors presented here the identification and characterization of a novel virostatic molecule against BTV, an aminothiophenecarboxylic acid derivative named compound 003 (C003). The virostatic efficacy of C003 could be improved via chemical modification, leading to a de novo synthesized compound 052 (C052). The 50% effective concentrations (EC50) of C003 and C052 were determined at 1.76±0.73 µM and 0.27±0.12 µM, respectively. The 50% cytotoxicity concentration (CC50) of C003 was over 100 µM and the CC50 of C052 was at 82.69 µM. Accordingly, the 50% selective index (SI50) of C003 and C052 against BTV was over 57 and 306, respectively. The inhibitory effect of C003/C052 on BTV-induced apoptosis was also confirmed via the inhibition of caspase-3/-7 activation post BTV infection. C003/C052 could inhibit BTV induced CPE even when added as late as 24 h.p.i., indicating that they might act at late stage of viral life-cycle. C003/C052 could reduce over two-logs of both the progeny virus production and the number of genomic viral RNA copies. Interestingly, both the activation of host autophagy and viral protein expression were inhibited post BTV infection when cells were treated with C003 and C052, suggesting that C003/C052 might act as virostatic agents via inhibiting host autophagy activation. Although further investigations might be needed to pin down the exact mechanism of C003/C052, this results suggested that these compounds might be potent lead compounds with potential novel mechanism of action against BTV.
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Regulation of neuraminidase expression in Streptococcus pneumoniae
Sialic acid (N-acetylneuraminic acid; NeuNAc) is one of the most important carbohydrates for Streptococcus pneumoniae due of its role as a carbon and energy source, receptor for adhesion and invasion and molecular signal for promotion of biofilm formation, nasopharyngeal carriage and invasion of the lung.
The role of Helicobacter pylori infection in the development of allergic asthma.
Asthma is one of the most prevalent chronic diseases in developed countries, with steady increases in asthma prevalence evident, particularly in the last few decades. As genetic factors are unlikely to contribute to the rise in asthma prevalence, changes in lifestyle and exposure to environmental stimuli have been proposed to account for this trend.
Genome-Scale Reconstruction and Analysis of the Metabolic Network in the Hyperthermophilic Archaeon Sulfolobus solfataricus
Authors of this article describe the reconstruction of a genome-scale metabolic model of the crenarchaeon Sulfolobus solfataricus, a hyperthermoacidophilic microorganism. It grows in terrestrial volcanic hot springs with growth occurring at pH 2–4 (optimum 3.5) and a temperature of 75–80°C (optimum 80°C). The genome of Sulfolobus solfataricus P2 contains 2,992,245 bp on a single circular chromosome and encodes 2,977 proteins and a number of RNAs. The network comprises 718 metabolic and 58 transport/exchange reactions and 705 unique metabolites, based on the annotated genome and available biochemical data.
Inhibition of Candida parapsilosis Fatty Acid Synthase (Fas2) Induces Mitochondrial Cell Death in Serum
Candida parapsilosis is a human opportunistic pathogen associated with significant morbidity and mortality, especially in immunocompromised individuals such as premature, low-birthweight neonates. In prior studies researchers have indicated that C. parapsilosis effectively utilizes fatty acids/lipids for growth and virulence.
A Novel Virulence Strategy for Pseudomonas aeruginosa Mediated by an Autotransporter with Arginine-Specific Aminopeptidase Activity
The opportunistic human pathogen, Pseudomonas aeruginosa, is a major cause of infections in chronic wounds, burns and the lungs of cystic fibrosis patients. The P. aeruginosa genome encodes at least three proteins exhibiting the characteristic three domain structure of autotransporters, but much remains to be understood about the functions of these three proteins and their role in pathogenicity.
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