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Microbiology Students Portal
Welcome to Microbiology Students Portal
16·March·2010 @ 9:06
| Microbiology/Infectious Disease |
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Microbiology/Infectious Disease
So there are probably only 15 facts necessary to pass Microbiology/Infectious Disease:
1. Staph Aureus is a gram (+), catalase (+), coagulase (+) cocci in clusters, natural penicillinase producer (use Oxacillin or nafcillin if MSSA), use Vancomycin, Linezolid, Daptomycin, and Polymyxin (probably in that order) if resistant.
2. Pneumonia? 3rd generation cephalosporin + Macrolide. Ceftriaxone (3rd gen cephalosporin, also great for Enterobacter, Neisseria, E. Coli) covers pneumococcus including resistant pneumococcus, hemophilus influenzae, and Klebsiella... + Azithromycin (Macrolide) covers chlamydophila pneumoniae, mycoplasma pneumoniae, legionella pneumophila, and bordetella pertussis. Done. I guess you could use a quinolone (tenditis and rupture possible, action on topoisomerase II and IV)...
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| A Genome-Wide Analysis of Small Regul... |
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A Genome-Wide Analysis of Small Regulatory RNAs in the Human Pathogen Group A Streptococcus
Abstract
The coordinated regulation of gene expression is essential for pathogens to infect and cause disease. A recently appreciated mechanism of regulation is that afforded by small regulatory RNA (sRNA) molecules. Here, we set out to assess the prevalence of sRNAs in the human bacterial pathogen group A Streptococcus (GAS). Genome-wide identification of candidate GAS sRNAs was performed through a tiling Affymetrix microarray approach and identified 40 candidate sRNAs within the M1T1 GAS strain MGAS2221. Together with a previous bioinformatic approach this brings the number of novel candidate sRNAs in GAS to 75, a number that approximates the number of GAS transcription factors. Transcripts were confirmed by Northern blot analysis for 16 of 32 candidate sRNAs tested, and the abundance of several of these sRNAs were shown to be temporally regulated. Six sRNAs were selected for further study and the promoter, transcriptional start site, and Rho-independent terminator identified for each. Significant variation was observed between the six sRNAs with respect to their stability during growth, and with respect to their inter- and/or intra-serotype-specific levels of abundance. To start to assess the contribution of sRNAs to gene regulation in M1T1 GAS we deleted the previously described sRNA PEL from four clinical isolates. Data from genome-wide expression microarray, quantitative RT-PCR, and Western blot analyses are consistent with PEL having no regulatory function in M1T1 GAS. The finding that candidate sRNA molecules are prevalent throughout the GAS genome provides significant impetus to the study of this fundamental gene-regulatory mechanism in an important human pathogen.
Citation: Perez N, Trevi?o J, Liu Z, Ho SCM, Babitzke P, et al. (2009) A Genome-Wide Analysis of Small Regulatory RNAs in the Human Pathogen Group A Streptococcus. PLoS ONE 4(11): e7668. doi:10.1371/journal.pone.0007668
Editor: Ramy K. Aziz, Cairo University, Egypt
Received: August 20, 2009; Accepted: October 12, 2009; Published: November 2, 2009
Copyright: ? 2009 Perez et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This research was funded in part by award number R21AI078159 from the National Institute of Allergy and Infectious Diseases (to P.S.), a TMHRI research scholar award (to P.S.), and by grant GM059969 from the National Institute of General Medical Sciences (to P.B.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: psumby@tmhs.org
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| Water Research Conference 2010 |
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Water Research Conference 2010: Challenges in Organic and Bioorganic Chemistry, Portugal
1-14 April 2010, at the Marriott Lisbon
Organiser: Elsevier Ltd.
Contact: Email: richard.hart @event-logistics.co. uk
Weblink: www.waterresearchconference.com
Microbiology is one of the major scientific disciplines contributing to the field of water research. In this conference we will provide a platform for exchange and interaction between microbiological research and its application; the provision of clean water to society.
The conference addresses two major topics:
* Shifting paradigms in the assessment of recreational
water quality
* Microbial ecology of drinking water and waste water treatment processes.
Presentations will consist of the latest research achievements as well as more general conceptual papers on the role of microbiology in Water Research.
Abstract submission deadline: 15 November 2009
Abstract Submission
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| Down-Regulation of Platelet Surface CD47 |
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Down-Regulation of Platelet Surface CD47 Expression in Escherichia coli O157:H7 Infection-Induced Thrombocytopenia
Abstract
Background
Platelet depletion is a key feature of hemolytic uremic syndrome (HUS) caused by Shiga toxin-producing Escherichia coli (STEC) infection. The mechanism underlying STEC-induced platelet depletion, however, is not completely understood.
Methodology/Principal Findings
Here we demonstrated for the first time that platelet surface expression of CD47 was significantly decreased in C57BL6 mice treated with concentrated culture filtrates (CCF) from STEC O157:H7. STEC O157:H7 CCF treatment also led to a sharp drop of platelet counts. The reduction of cell surface CD47 was specific for platelets but not for neutrophil, monocytes and red blood cells. Down-regulation of platelet surface CD47 was also observed in isolated human platelets treated with O157:H7 CCF. Platelet surface CD47 reduction by O157:H7 CCF could be blocked by anti-TLR4 antibody but not anti-CD62 antibody. Down-regulation of platelet surface CD47 was positively correlated with platelet activation and phagocytosis by human monocyte-derived macrophages. Furthermore, the enhanced phagocytosis process of O157:H7 CCF-treated platelets was abolished by addition of soluble CD47 recombinants.
Conclusions/Significance
Our results suggest that platelet CD47 down-regulation may be a novel mechanism underneath STEC-induced platelet depletion, and that the interactions between CD47 and its receptor, signal regulatory protein α (SIRPα), play an essential role in modulating platelet homeostasis.
Citation: Guo Y-L, Liu D-Q, Bian Z, Zhang C-Y, Zen K (2009) Down-Regulation of Platelet Surface CD47 Expression in Escherichia coli O157:H7 Infection-Induced Thrombocytopenia. PLoS ONE 4(9): e7131. doi:10.1371/journal.pone.0007131
Editor: Adam J. Ratner, Columbia University, United States of America
Received: June 15, 2009; Accepted: August 24, 2009; Published: September 22, 2009
Copyright: ? 2009 Guo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by research grants from Nanjing University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
*
E-mail: cyzhang@nju.edu.cn (CYZ)>kzen@nju.edu.cn (KZ); cyzhang@nju.edu.cn (CYZ)
# These authors contributed equally to this work.
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| Distinct Gene Number-Genome Size... |
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Distinct Gene Number-Genome Size Relationships for Eukaryotes and Non-Eukaryotes: Gene Content Estimation for Dinoflagellate Genomes
Yubo Hou, Senjie Lin*
Department of Marine Sciences, University of Connecticut, Groton, Connecticut, United States of America
Abstract
The ability to predict gene content is highly desirable for characterization of not-yet sequenced genomes like those of dinoflagellates. Using data from completely sequenced and annotated genomes from phylogenetically diverse lineages, we investigated the relationship between gene content and genome size using regression analyses. Distinct relationships between log10-transformed protein-coding gene number (Y′) versus log10-transformed genome size (X′, genome size in kbp) were found for eukaryotes and non-eukaryotes. Eukaryotes best fit a logarithmic model, Y′ = ln(-46.200+22.678X′, whereas non-eukaryotes a linear model, Y′ = 0.045+0.977X′, both with high significance (p<0.001, R2>0.91). Total gene number shows similar trends in both groups to their respective protein coding regressions. The distinct correlations reflect lower and decreasing gene-coding percentages as genome size increases in eukaryotes (82%?1%) compared to higher and relatively stable percentages in prokaryotes and viruses (97%?47%). The eukaryotic regression models project that the smallest dinoflagellate genome (3?106 kbp) contains 38,188 protein-coding (40,086 total) genes and the largest (245?106 kbp) 87,688 protein-coding (92,013 total) genes, corresponding to 1.8% and 0.05% gene-coding percentages. These estimates do not likely represent extraordinarily high functional diversity of the encoded proteome but rather highly redundant genomes as evidenced by high gene copy numbers documented for various dinoflagellate species.
Citation: Hou Y, Lin S (2009) Distinct Gene Number-Genome Size Relationships for Eukaryotes and Non-Eukaryotes: Gene Content Estimation for Dinoflagellate Genomes. PLoS ONE 4(9): e6978. doi:10.1371/journal.pone.0006978
Editor: Rosemary Jeanne Redfield, University of British Columbia, Canada
Received: May 19, 2009; Accepted: August 14, 2009; Published: September 14, 2009
Copyright: ? 2009 Hou, Lin. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by the NSF grants OCE-0452780 and EF-0626678. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: senjie.lin@uconn.edu
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