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Misfolded proteins are not just useless — they can be toxic. Some of them form linear aggregates known as amyloid fibres that can lead to disorders such as Alzheimer’s and Parkinson’s diseases. Writing in PLoS Biology, James Shorter and colleagues describe a protein machinery that inhibits the formation and helps to dissolve such fibres.
Heat shock proteins (HSPs) assist other proteins in folding. The authors set out to study whether two small HSPs from baker’s yeast (Hsp26 and Hsp42........ Read more »
Duennwald ML, Echeverria A, Shorter J. (2012) Small Heat Shock Proteins Potentiate Amyloid Dissolution by Protein Disaggregases from Yeast and Humans. PLoS Biol. DOI: 10.1371/journal.pbio.1001346
Multiple sclerosis is an autoimmune disease of the central nervous system that causes neurological disability in young adults. Several environmental and genetic factors have been linked to the disease, but the precise mechanisms involved, and whether neurological damage precedes inflammation or vice versa, remain unclear.
In a recent article published in Nature, an international consortium of researchers report the identification of 29 new susceptibility loci, most of which are related to im........ Read more »
The International Multiple Sclerosis Genetics Consortium . (2011) Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis. Nature, 476(7359), 214-219. DOI: 10.1038/nature10251
The March issue of International Microbiology included a very nice article by Roberto Kolter, professor of Microbiology and Molecular Genetics at Harvard Medical School. The title is Biofilms in lab and nature: a molecular geneticist’s voyage to microbial ecology (freely available as PDF).In the article, the author gives an entertaining account of the path that lead him to the study of biofilms -- that is, aggregations of microbes growing on solid substrates. He also highlights some of his rec........ Read more »
Roberto Kolter. (2010) Biofilms in lab and nature: a molecular geneticist’s voyage to microbial ecology. Int. Microbiol., 1-7. info:/10.2436/20.1501.01.105
This post is about pneumonia and pneumococci, fratricide at the cellular level, and a pretty protein. And there's a video too!First things first. Pneumonia is a common disease characterized by inflammation of the lungs that can be deadly: 4 million people in the world die from it every year. Half of them are children under 5 years of age -- in fact, no other illness causes more deaths of children under age 5 worldwide. However, this is a preventable and treatable disease in most cases.Many organ........ Read more »
Pérez-Dorado, I., González, A., Morales, M., Sanles, R., Striker, W., Vollmer, W., Mobashery, S., García, J., Martínez-Ripoll, M., García, P.... (2010) Insights into pneumococcal fratricide from the crystal structures of the modular killing factor LytC. Nature Structural . DOI: 10.1038/nsmb.1817
The following videos are two short documentaries made by students in the MIT Graduate Program in Science Writing. Both films refer to a recent discovery of new antibiotics by scientists at the Massachusetts Institute of Technology and the University of Florida. But, please, don't say: "bah, another antibiotic discovering, so boring". What makes this an interesting story is not the particular antibiotics themselves (we'll see if they ever become useful), but the way they were discovered. Or shoul........ Read more »
K. Kurosawa, I. Ghiviriga, T.G. Sambandan, P.A. Lessard, J.E. Barbara, C. Rha, & A.J. Sinskey. (2008) Rhodostreptomycins, Antibiotics Biosynthesized Following Horizontal Gene Transfer from Streptomyces padanus to Rhodococcus fascians. Journal of the American Chemical Society, 130(4), 1126-1127. http://pubs.acs.org/cgi-bin/doilookup/?10.1021/ja077821p
Polyketides are a class of natural products isolated from microbes, plants and invertebrates which includes an impressive number of clinically effective drugs with diverse activities. To name a few examples: erythromycin (antibiotic), rapamycin (immunosuppressive), amphotericin (antifungal), avermectin (antiparasitic), and doxorubicin (anticancer). As other natural products do, polyketides may play disparate roles in the producing organisms, from defensive weapons (inhibiting growth of competito........ Read more »
Tarun Chopra, Srijita Banerjee, Sarika Gupta, Gitanjali Yadav, Swadha Anand, Avadhesha Surolia, Rajendra Roy, Debasisa Mohanty, Rajesh Gokhale, & Bradley Moore. (2008) Novel Intermolecular Iterative Mechanism for Biosynthesis of Mycoketide Catalyzed by a Bimodular Polyketide Synthase. PLoS Biology, 6(7). DOI: 10.1371/journal.pbio.0060163
According to the endosymbiotic theory, eukaryotic organelles (mitochondria, chloroplasts) are the remains of certain bacteria that established intimate associations with eukaryote ancestors. This theory is widely supported by biochemical, genetic and proteomic evidences. A take-home message may be: a bacterium became an endosymbiont, then degenerated, and voilà, turned into an organelle. But that's an oversimplification. A full story should include an active participation of the host........ Read more »
Jinling Huang, & Johann Gogarten. (2007) Did an ancient chlamydial endosymbiosis facilitate the establishment of primary plastids?. Genome Biology, 8(6). DOI: 10.1186/gb-2007-8-6-r99
Ahmed Moustafa, Adrian Reyes-Prieto, Debashish Bhattacharya, & Robert DeSalle. (2008) Chlamydiae Has Contributed at Least 55 Genes to Plantae with Predominantly Plastid Functions. PLoS ONE, 3(5). DOI: 10.1371/journal.pone.0002205
When nutrients are scarce, Bacillus subtilis cells are able to form highly resistant endospores. However, even in a clonal population, only some cells engage in the sporulation process. This is explained in terms of a bet-hedging strategy: a mixed population composed of both vegetative cells and spores is prepared for a variety of unknown future environments. But how does an individual cell determine its own fate? In a recent report, J. W. Veening et al. showed that the decision (to sporulate or........ Read more »
J-W Veening, E Stewart, T Berngruber, F Taddei, O Kuipers, & L Hamoen. (2008) Bet-hedging and epigenetic inheritance in bacterial cell development. Proceedings of the National Academy of Sciences, 105(11), 4393-4398. DOI: 10.1073/pnas.0700463105
The so-called neglected diseases comprise a number of parasitic and bacterial infections which are the most common afflictions of humankind. So, how can these diseases be "neglected"? When you get sick, you don't ignore your illness, do you? But we all can ignore a disease... as long as we ourselves don't suffer it.
Neglected diseases are especially endemic in low-income populations in developing regions of Africa, Asia, and the Americas. They mostly affect the poorest peopl........ Read more »
Mangai Balasegaram, Sooria Balasegaram, Denis Malvy, Pascal Millet, & Peter Hotez. (2008) Neglected Diseases in the News: A Content Analysis of Recent International Media Coverage Focussing on Leishmaniasis and Trypanosomiasis. PLoS Neglected Tropical Diseases, 2(5). DOI: 10.1371/journal.pntd.0000234
That's why there are no insects as big as horses [*], or bacteria as large as to be seen without the use of a microscope. Well, actually, the latter is not true —although a typical bacterial cell is not longer than 5 micrometers, a few species such as Thiomargarita namibiensis (left image) and Epulopiscium fishelsoni may reach a length of over 0.5 millimeters (500 micrometers); enough to become visible to the naked eye.
Big bacteria enjoy some advantages; for instance,........ Read more »
J Mendell, K D Clements, J H Choat, & E R Angert. (2008) From the Cover: Extreme polyploidy in a large bacterium. Proceedings of the National Academy of Sciences, 105(18), 6730-6734. DOI: 10.1073/pnas.0707522105
At the right concentration, an antibiotic may be effective enough to kill a microbe, or at least to stop its growth. But lower antibiotic concentrations may have subtler effects on microorganisms. For instance, some bacteria respond in a funny way to very low, sub-lethal amounts of those antibiotics inhibiting cell division (such as penicillins): instead of dividing, cells become longer and longer, forming filaments. In this situation, cells are stressed but alive and still growing. Now,...
[Pl........ Read more »
André Comeau, Françoise Tétart, Sabrina N Trojet, Marie-Françoise Prère, H M Krisch, & Debbie Fox. (2007) Phage-Antibiotic Synergy (PAS): β-Lactam and Quinolone Antibiotics Stimulate Virulent Phage Growth. PLoS ONE, 2(8). DOI: 10.1371/journal.pone.0000799
Do you want to increase your productivity? Buy a ticket for the next spaceflight!
It may work... if you are a microbe with the ability to produce an interesting metabolite, such as an antifungal agent. The treatment involves some kind of unknown mutation, but that's OK as long as you become a better producer with a stable behavior.
Scientists from Zhejiang University and Shandong Lukang Pharmaceutical Co. (China), recently published the following article:
Jingle, L., Jianping, L., Zhinan........ Read more »
Liang Jingle, Lin Jianping, Xu Zhinan, Su Wei, & Cen Peilin. (2007) Space-flight mutation of Streptomyces gilvosporeus for enhancing natamycin production. Chinese Journal of Chemical Engineering, 15(5), 720-724. http://www.cjche.com.cn/qikan/epaper/zhaiyao.asp?bsid
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