from Henrik Christensen and Magne Bisgaard in Pasteurellaceae: Biology, Genomics and Molecular Aspects

The family Pasteurellaceae Pohl 1981 includes 38 properly classified species in addition to 24 misclassified species. The majority of taxa have been isolated from disease conditions in warm blooded animals and in particular in farm animals. These bacteria are obligate parasites or commensals of vertebrates, colonizing mainly the mucosal surfaces of the upper respiratory tract, oropharynx, and reproductive tracts and possibly also parts of the intestinal tract. Most taxa represent potential pathogens although mechanisms of virulence have remained unknown or doubtful until recent years. Both systemic and local infections have been reported for most taxa involved in diseases. However, pneumonia has been reported most frequently out of a number of other disease manifestations. Fossil remnants of members of Pasteurellaceae have never been reported and information on the diversification of taxa within the family can only be obtained by phylogenetic reconstruction. Most likely the current members of Pasteurellaceae might have been present as common ancestors of for example birds and dinosaurs. For marsupials, monotremes and reptiles information is very limited and further insight from these groups would be very helpful to test the hypothesis of co-evolution of host and parasite.

Further reading: Pasteurellaceae: Biology, Genomics and Molecular Aspects

Labels: bacterium, Haemophilus, model organism, pasteurella, Pasteurellaceae

from Christina Egan, Nick M. Cirino and Kimberlee A. Musser in Real-Time PCR: Current Technology and Applications

With the public's reawakened concern regarding use of biological agents as weapons, the rapid detection, discrimination, and identification of pathogenic organisms and toxins has become a priority for state and federal government agencies. High confidence, cost effective, and near real-time diagnostic methods are essential to protecting national health security whether the target is public health, agriculture, commodities, or water supply infrastructures. While culture-based methods have been, and will likely remain, the gold standard for microbiological diagnostics, PCR-based tests offer significant advantages in sensitivity, specificity, speed and data richness that make them invaluable to diagnostic laboratories. We describe the application of real-time PCR methods in biodefense and discuss the use of real-time PCR in biodefense in terms of general workflow and processing considerations, clinical diagnostic applications, environmental diagnostic applications, and multiplex screening. Real-time PCR assays can be either quantitative (qPCR) or qualitative, depending on whether a standard curve is included with the analytical run. Most diagnostic and biodefense applications utilise the qualitative nature of real-time PCR as a detection platform. We consider the future uses and anticipated advances in real-time PCR applications as related to biodefense.

Further reading: Real-Time PCR: Current Technology and Applications

Labels: biodefense, PCR, qPCR, real-time PCR

from Chandra Iyer and James Versalovic

Beneficial bacteria include Lactobacillus and Bifidobacterium spp. and other lactic acid bacteria (LAB) commonly known as probiotics. LAB possesses numerous potential therapeutic properties including anti-inflammatory and anti-cancer activities and other features of interest. In recent years, studies with in vitro cell culture and animal models that clearly demonstrated protective effects of LAB for anti-tumor and anti-cancer effects. Dietary administration of LAB alleviated the risks of certain types of cancers and suppressed colonic tumor incidence, volume and multiplicity induced by various carcinogens in different animal models. Oral administration of LAB effectively reduced DNA adduct formation, ameliorated DNA damage and prevented putative preneoplastic lesions such as aberrant crypt foci induced by chemical carcinogens in the gastrointestinal (GI) tract of various animal models. LAB also increased the latency period and survival rates in test animals when challenged with carcinogenic agents. Reports also indicated that LAB cultures administered to animals inhibited liver, colon, bladder and mammary tumors, highlighting potential systemic effects of probiotics with anti-neoplastic activities.

Further reading: Lactobacillus Molecular Biology: From Genomics to Probiotics

Labels: Bifidobacterium, cancer, lactic acid bacteria, lactobacillus, probiotics

The biochemical capacity to use water as the source for electrons in photosynthesis evolved once, in a common ancestor of extant cyanobacteria. The geological record indicates that this transforming event took place early in our planet's history, at least 2450-2320 million years ago (Ma), and possibly much earlier. Geobiological interpretation of Archean (>2500 Ma) sedimentary rocks remains a challenge; available evidence indicates that life existed 3500 Ma, but the question of when oxygenic photosynthesis evolved continues to engender debate and research. A clear paleontological window on cyanobacterial evolution opened about 2000 Ma, revealing an already diverse biota of blue-greens. Cyanobacteria remained principal primary producers throughout the Proterozoic Eon (2500-543 Ma), in part because the redox structure of the oceans favored photautotrophs capable of nitrogen fixation. Green algae joined blue-greens as major primary producers on continental shelves near the end of the Proterozoic, but only with the Mesozoic (251-65 Ma) radiations of dinoflagellates, coccolithophorids, and diatoms did primary production in marine shelf waters take modern form. Cyanobacteria remain critical to marine ecosystems as primary producers in oceanic gyres, as agents of biological nitrogen fixation, and, in modified form, as the plastids of marine algae.

From: Andrew H. Knoll in The Cyanobacteria: Molecular Biology, Genomics and Evolution

Labels: archaea, bacteriology, bacterium, cyanobacteria

Scientists at the Institute of Food Research, Norwich UK found that probiotic bacteria in a daily drink can modify the immune system's response to grass pollen. Volunteers with a history of seasonal hay fever drank a daily milk drink with or without live Lactobacillus casei over 5 months. The study was double-blinded and placebo controlled, so neither the volunteers nor the scientists knew who had been assigned the probiotic drinks.

Blood samples were taken before the grass pollen season, then again when it was at its peak (June), and 4 weeks after the end of season. There were no significant differences in levels of IgE in the blood between the two groups at the start of the study, but IgE levels were lower in the probiotic group both at the peak season and afterwards. IgE stimulates the release of histamine which produces the symptoms of hayfever.

Further reading: Lactobacillus Probiotics

Labels: bacteriology, biotechnology, lactic acid bacteria, lactobacillus, probiotics

A number of book reviews on microbiology books have been published recently. Extracts provided below:

BACILLUS: CELLULAR AND MOLECULAR BIOLOGY
"The quality of the chapters is uniformly high. Together they provide a review of significant progress toward a better and deeper understanding of the physical structure and molecular biological organization and function in Bacillus subtilis. As a consequence, a truly intimate grasp of this bacterium is achieved." from The Quarterly Review of Biology
Further information: BACILLUS

REAL-TIME PCR IN MICROBIOLOGY: FROM DIAGNOSIS TO CHARACTERIZATION
"... enjoyable and easy to read ... well-referenced and provide an easy to follow explanation, especially the chapter on fluorogenic chemistry which also has clear illustrations. The table of design rules for oligonucleotide and probes provided a good summary in an easy-to-read format. ... an interesting insight into the thoughts of the current leaders in their fields. This book shows what a versatile and sensitive tool real-time PCR can be and the many uses it can be put too. In my opinion this book would be useful for the novice because of the background information it provides." from Microbiology Today
Further information: REAL-TIME PCR

PSEUDOMONAS: GENOMICS AND MOLECULAR BIOLOGY
"... the contribution by Fajardo & Martinez on antibiotic resistance provides a wealth of background information on this clinically relevant topic ... the contributions by Haussler and Klockgether et al. give insight into recent progress made in the areas of small colony variants and genome diversity of P. aeruginosa, respectively. Three other chapters provide useful complementary information ... Institutions with an interest in Pseudomonas research should consider acquiring this book." from Microbiology Today
Further information: PSEUDOMONAS

MOLECULAR ORAL MICROBIOLOGY
"... a broad and comprehensive text covering the molecular aspects of dental caries and periodontal disease. Accompanying each of the fully referenced chapters are detailed illustrations and the inclusion of high-quality colour equivalents of these figures at the end of the book is welcome. ... of value to all microbiologists with an interest in molecular microbiology ... excellent overview of current methodologies ... appeal to dental undergraduates and postgraduates." from Microbiology Today
Further information: ORAL MICROBIOLOGY

EPIGENETICS
"... a significant collection of articles, relating to various aspects of epigenetics. The text is clear and concise and all reports include accurate data and figures. ... will assist researchers in the field and provides an important introductory reference for scientists that want to embark on such research. It is highly recommended for personal and institutional purchase." from Microbiology Today
Further information: EPIGENETICS

Labels: bacillus, book review, epigenetics, oral microbiology, Pseudomonas, real-time PCR