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MicrobiologyBytes: The latest news about microbiology in a form that everyone can understand.
Listeria monocytogenes is an intracellular bacterial pathogen that replicates rapidly in the cytosol of host cells during acute infection. Surprisingly, these bacteria were found to occupy vacuoles in liver granuloma macrophages during persistent infection of severe combined immunodeficient (SCID) mice. Here we show that L. monocytogenes can replicate in vacuoles within macrophages. In livers of ... Read more »
Cheryl Birmingham, Veronica Canadien, Natalia A Kaniuk, Benjamin E Steinberg, Darren E Higgins, & John H Brumell. (2008) Listeriolysin O allows Listeria monocytogenes replication in macrophage vacuoles. Nature, 451(7176), 350-354. DOI: 10.1038/nature06479
It’s hard to get a handle on how big, fat viruses such as herpesviruses and poxviruses infect cells because they have so many potential virus attachment proteins on their surface and these interact with a range of cellular receptors in different circumstances. However, recent research from the University of Pennsylvania has considerably improved our knowledge ... Read more »
D Atanasiu, J Whitbeck, T Cairns, B Reilly, G Cohen, & R Eisenberg. (2007) Bimolecular complementation reveals that glycoproteins gB and gH/gL of herpes simplex virus interact with each other during cell fusion. Proceedings of the National Academy of Sciences, 104(47), 18718-18723. DOI: 10.1073/pnas.0707452104
Today’s issue of Science describes how a group of scientists led by Craig Venter have built an entire bacterial genome from scratch, i.e. starting with simple laboratory chemicals and finishing with a 582,970 base pair DNA chromosome. So is this the end of the world? Have mad scientists created a Frankenstein bug which ... Read more »
D Gibson, G A Benders, C Andrews-Pfannkoch, E A Denisova, H Baden-Tillson, J Zaveri, T B Stockwell, A Brownley, D W Thomas, M A Algire.... (2008) Complete Chemical Synthesis, Assembly, and Cloning of a Mycoplasma genitalium Genome. Science. DOI: 10.1126/science.1151721
The recent list of completely sequenced microbial genomes is relatively short. Still, it includes some remarkable environmental microorganisms, such as the sulfur-reducing crenarchaeon Ignicoccus hospitalis, host of the smallest archaeon Nanoarchaeum equitans, a marine bacterium that degrades nitramine explosives and two enterobacteria that are commonly found in soil and water habitats but can also infect ... Read more »
Michael Galperin. (2007) Some bacteria degrade explosives, others prefer boiling methanol. Environmental Microbiology, 9(12), 2905-2910. DOI: 10.1111/j.1462-2920.2007.01480.x
Human papillomaviruses (HPVs) are small, double-stranded DNA viruses that exhibit tropism for epithelial cells. Approximately one-third of the 100 HPV types identified infect epithelial cells of the genital tract, and a subset are the etiological agents of cervical cancers. HPVs infect cells in the basal layer of the epithelium, which become exposed through microlesions. After ... Read more »
C Moody, A Fradet-Turcotte, J Archambault, & L A Laimins. (2007) Human papillomaviruses activate caspases upon epithelial differentiation to induce viral genome amplification. Proceedings of the National Academy of Sciences, 104(49), 19541-19546. DOI: 10.1073/pnas.0707947104
Replication of many picornaviruses is inhibited by low concentrations of guanidine. Guanidine-resistant mutants are readily isolated and the mutations map to the coding region for the 2C protein. Using in vitro replication assays it has been determined previously that guanidine blocks the initiation of negative-strand synthesis. This paper examines the dynamics of RNA replication, measured ... Read more »
G Belsham, & P Normann. (2008) Dynamics of picornavirus RNA replication within infected cells. Journal of General Virology, 89(2), 485-493. DOI: 10.1099/vir.0.83385-0
Parasite-driven declines in wildlife have become increasingly common and can pose significant risks to natural populations. Thes authors used the IUCN Red List of Threatened and Endangered Species and compiled data on hosts threatened by infectious disease and their parasites to better understand the role of infectious disease in contemporary host extinctions. The majority of ... Read more »
AMY PEDERSEN, KATE E JONES, CHARLES L NUNN, & SONIA ALTIZER. (2007) Infectious Diseases and Extinction Risk in Wild Mammals. Conservation Biology, 21(5), 1269-1279. DOI: 10.1111/j.1523-1739.2007.00776.x
Few bacteria are loners - more often they grow in crowds and squat on surfaces where they form a community. These so-called biofilms develop on any surface that bacteria can attach themselves to. The dilemma we face is that neither disinfectants and antibiotics, nor phagocytes (cells which typically destroy microorganisms) and our immune system can ... Read more »
Carsten Matz, Jeremy S. Webb, Peter J. Schupp, Shui Yen Phang, Anahit Penesyan, Suhelen Egan, Peter Steinberg, Staffan Kjelleberg, & Craig R. McClain. (2008) Marine Biofilm Bacteria Evade Eukaryotic Predation by Targeted Chemical Defense. PLoS ONE, 3(7). http://dx.plos.org/10.1371/journal.pone.0002744
The interferon (IFN) system is an extremely powerful antiviral response that is capable of controlling most, if not all, virus infections in the absence of adaptive immunity. However, viruses can still replicate and cause disease in vivo, because they have some strategy for at least partially circumventing the IFN response. A great deal has been ... Read more »
R Randall, & S Goodbourn. (2008) Interferons and viruses: an interplay between induction, signalling, antiviral responses and virus countermeasures. Journal of General Virology, 89(1), 1-47. DOI: 10.1099/vir.0.83391-0
Although vaccination has almost eliminated measles in parts of the world, the disease remains a major killer in some high birth rate countries of the Sahel. On the basis of measles dynamics for industrialized countries, high birth rate regions should experience regular annual epidemics. This article shows that measles epidemics in Niger are highly episodic, ... Read more »
The first thing you need to know about this topic is how to pronounce it! If you were an Ancient Greek, you may have said “ap-a-tow-sis”, but most people these days say “a-pop-tow-sis”, and everyone knows what they mean, so don’t worry about it. Apoptosis or “programmed cell death”, is a critical mechanism in tissue ... Read more »
It has been known for over 50 years that Polyomaviruses can cause cancers in animals, but until now, there has been no scientific evidence that these viruses cause human cancers. Merkel cell polyomavirus (MCV) was discovered by the husband-and-wife team who found the cause of Kaposi’s sarcoma using a new strategy to hunt for human ... Read more »
H Feng, M Shuda, Y Chang, & P Moore. (2008) Clonal Integration of a Polyomavirus in Human Merkel Cell Carcinoma. Science. DOI: 10.1126/science.1152586
Some estimates put total the worldwide economic damage due to plant viruses as high as US$60 billion per year, in addition to the human costs in terms of hunger and poverty. So understanding how viruses damage plants and how this can be avoided is of the utmost importance. There are hundreds of plant-pathogenic viruses, ... Read more »
MARCEL PRINS, MARGIT LAIMER, EMANUELA NORIS, JÖRG SCHUBERT, MICHAEL WASSENEGGER, & MARK TEPFER. (2007) Strategies for antiviral resistance in transgenic plants. Molecular Plant Pathology, 2147483647. DOI: 10.1111/j.1364-3703.2007.00447.x
A previous study indicated that approximately 30% of cultivable soil bacteria may contain inducible prophage; however, the degree to which this cultivation-based estimate applies to indigenous soil bacteria is unknown. To estimate the prevalence of lysogeny within soil bacterial communities, induction assays were carried out by extracting bacteria from soil and subsequently exposing extracts ... Read more »
Kurt Williamson, Mark Radosevich, David W Smith, & K Eric Wommack. (2007) Incidence of lysogeny within temperate and extreme soil environments. Environmental Microbiology, 9(10), 2563-2574. DOI: 10.1111/j.1462-2920.2007.01374.x
A controversial news commentary in the subscription-only journal Nature on 14th February (Happy Valentine’s Day) reports on
HIV’s status as an ‘incurable’ infection, although in many cases doctors are able to stave off the onset of full-blown AIDS by giving patients sustained courses of drugs.
This item was based on an article published in May 2007:
Decay of ... Read more »
Tae‐Wook Chun, David C Nickle, Jesse S Justement, Jennifer H Meyers, Gregg Roby, Claire W Hallahan, Shyam Kottilil, Susan Moir, JoAnn M Mican, James I Mullins.... (2008) Persistence of HIV in Gut‐Associated Lymphoid Tissue despite Long‐Term Antiretroviral Therapy. The Journal of Infectious Diseases, 2147483647. DOI: 10.1086/527324
If you’ve studied virology, you’ll be familiar with the concept of a virus attachment protein, the protein(s) a virus uses to bind to the receptors on a host cell during infection. That’s all very well, but what happens after the virus has replicated and the new particles want to leave to find new host cells? ... Read more »
Stuart Neil, Trinity Zang, & Paul D Bieniasz. (2008) Tetherin inhibits retrovirus release and is antagonized by HIV-1 Vpu. Nature, 451(7177), 425-430. DOI: 10.1038/nature06553
The peptidoglycan layer is a unique and essential structural element in the cell wall of most bacteria (Peptidoglycan structure and architecture. FEMS Microbiology Reviews, 08 Jan 2008). Made of glycan strands cross-linked by short peptides, the so-called peptidoglycan sacculus forms a closed, bag-shaped structure surrounding the cytoplasmic membrane. Peptidoglycan sacculi have the strength ... Read more »
The quality and safety of food products are among the most important factors influencing consumer choices in modern times, as well as being important considerations of food manufacturers and distributors. It is therefore of importance for the food industry to continue to seek out more effective methods to reduce undesirable changes in foods associated with ... Read more »
Kiera Considine, Alan L Kelly, Gerald F Fitzgerald, Colin Hill, & Roy D Sleator. (2008) High-pressure processing – effects on microbial food safety and food quality. FEMS Microbiology Letters, 2147483647. DOI: 10.1111/j.1574-6968.2008.01084.x
Nitrogen is essential for all plants and animals, but despite being surrounded by it the element constitutes 79% of air on earth only a few bacteria can absorb it directly from the environment. All other species are ultimately dependent on these microbes as a source. A new paper in the open-access journal PLoS Biology investigates ... Read more »
Katharina Markmann, Gábor Giczey, & Martin Parniske. (2008) Functional Adaptation of a Plant Receptor- Kinase Paved the Way for the Evolution of Intracellular Root Symbioses with Bacteria. PLoS Biology, 6(3). DOI: 10.1371/journal.pbio.0060068
Radionuclides in the environment are one of the major concerns to human health and ecotoxicology. The explosion at the Chernobyl nuclear power plant renewed interest in the role played by fungi in mediating radionuclide movement in ecosystems. As a result of these studies, our knowledge of the importance of fungi, especially in their mycorrhizal habit, ... Read more »
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