MedWorm: Microbiology Top 20

Transcriptional Regulation of Mycobacterium tuberculosis PE/PPE Genes: A Molecular Switch to Virulence?

Journal of Molecular Microbiology and Biotechnology — Wed, 25 Jan 2012 04:04:07 +0100

J Mol Microbiol Biotechnol 2011;21:97–109 (DOI:10.1159/000329489) (Source: Journal of Molecular Microbiology and Biotechnology)

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Phylogenetic Characterization of Transport Protein Superfamilies: Superiority of SuperfamilyTree Programs over Those Based on Multiple Alignments

Journal of Molecular Microbiology and Biotechnology — Wed, 25 Jan 2012 04:04:06 +0100

J Mol Microbiol Biotechnol 2011;21:83–96 (DOI:10.1159/000334611) (Source: Journal of Molecular Microbiology and Biotechnology)

Identification of Two Novel Reductases Involved in Equol Biosynthesis in Lactococcus Strain 20–92

Journal of Molecular Microbiology and Biotechnology — Wed, 25 Jan 2012 04:04:06 +0100

J Mol Microbiol Biotechnol 2011;21:160–172 (DOI:10.1159/000335049) (Source: Journal of Molecular Microbiology and Biotechnology)

Revealing the Latent Mobilization Capability of the Staphylococcal Bacteriocinogenic Plasmid pRJ9

Journal of Molecular Microbiology and Biotechnology — Wed, 25 Jan 2012 04:04:06 +0100

J Mol Microbiol Biotechnol 2011;21:173–183 (DOI:10.1159/000335356) (Source: Journal of Molecular Microbiology and Biotechnology)

Domain organization of Legionella effector SetA

Cellular Microbiology — Tue, 31 Jan 2012 20:40:43 +0100

SummaryLegionella pneumophila is a human pathogen causing severe pneumonia called Legionnaires' disease. Multiple Legionella effectors are type IV‐secreted into the host cell to establish a specific vesicular compartment for pathogen replication. Recently it has been reported that the Legionella effector SetA shares sequence similarity with glycosyltransferases and interferes with vesicular trafficking of host cells (Heidtman et al., 2009, Cell Microbiol 11: 230). Here we show that SetA possesses glycohydrolase and mono‐O‐glucosyltransferase activity by using UDP‐glucose as a donor substrate. Whereas the catalytic activity is located at the N terminus of SetA, the C terminus (amino acids 401‐644) is essential for guidance of SetA to vesicular compartments of host cells. EGFP‐Se...

Serum albumin disrupts cryptococcus neoformans and bacillus anthracis extracellular vesicles

Cellular Microbiology — Tue, 31 Jan 2012 05:00:00 +0100

SummaryFor both pathogenic fungi and bacteria, extracellular vesicles have been shown to contain many microbial components associated with virulence, suggesting a role in pathogenesis. However, there are many unresolved issues regarding vesicle synthesis and stability, including the fact that vesicular packaging for extracellular factors involved in virulence must also have a mechanism for vesicle unloading. Consequently, we studied the kinetics of vesicle production and stability using [1‐14C] palmitic acid metabolic labeling and dynamic light scattering techniques. Cryptococcus neoformans vesicles were produced throughout all stages of fungal culture growth and they were stable once isolated. Density gradient analysis revealed that only a portion of the vesicle population carried crypt...

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Dynamics of DNA Double-strand Break Repair in Bacillus subtilis

Microbiology Blog: The weblog for microbiologists. — Thu, 02 Feb 2012 05:00:05 +0100

from Begoña Carrasco, Paula P. Cardenas, Cristina Cañas, Tribuhwuan Yadav, Carolina E. César, Silvia Ayora and Juan C. Alonso writing in Bacillus: Cellular and Molecular Biology (Second edition):All organisms have developed a variety of DNA repair mechanisms to cope with DNA lesions. Homologous recombination (HR), which uses a homologous template to restore lost information at the break site, is the ultimate step for repair of one- or two-ended double strands breaks (DSBs) and for promoting the re-establishment of replication forks. Genetic and cytological approaches were used to analyze the requirements of exponentially growing Bacillus subtilis cells to survive chemical or physical agents that generate one- or two-ended DSBs and the choreography of DSB repair. The da...

Calpastatin upregulation in Mycoplasma hyorhinis‐infected cells is promoted by the mycoplasma lipoproteins via the NF‐κB pathway

Cellular Microbiology — Tue, 31 Jan 2012 05:00:00 +0100

SummaryMycoplasma hyorhinis frequently contaminates cultured cells, with effects on synthetic and metabolic pathways. We demonstrated for the first time that contamination of cells by a strain of M. hyorhinis (NDMh) results in increased levels of calpastatin (the endogenous inhibitor of the ubiquitous Ca2+‐dependent protease calpain). We now show that the calpastatin upregulation by NDMh in neuroblastoma SH‐SY5Y cells resides in the NDMh lipoprotein fraction (LPP), via the NF‐κB transcription pathway. NF‐κB activation requires dissociation of the cytoplasmic NF‐κB/IκB complex followed by NF‐κB translocation to the nucleus. NDMh‐LPP induced translocation of the NF‐κB/RelA subunit to the nucleus and upregulated calpastatin. RelA translocation and calpastatin elevation w...

Beta‐hexosaminidase activity of the oral pathogen Tannerella forsythia influences biofilm formation on glycoprotein substrates

FEMS Immunology and Medical Microbiology — Sat, 28 Jan 2012 03:22:17 +0100

Infections in Heart and Lung Transplant Recipients

Clinical Microbiology Newsletter — Sun, 22 Jan 2012 02:22:47 +0100

Abstract: Patients undergoing thoracic organ transplantation procedures involving the heart or lung are at increased risk for developing a wide variety of infections due to their underlying immunosuppression and/or other factors. Lung transplant recipients are at high risk for developing infections caused by bacteria, viruses, and opportunistic fungi, whereas heart transplant recipients are at risk for developing infections caused by these same microorganisms, as well as parasitic infections, including toxoplasmosis and New World trypanosomiasis. This review will highlight the various infections that thoracic organ transplant recipients may develop following their procedures. (Source: Clinical Microbiology Newsletter)

Call for Submissions

Clinical Microbiology Newsletter — Sun, 22 Jan 2012 02:22:47 +0100

The editors would like to receive interesting case reports from our readers for possible publication in the Newsletter. Submitted case reports should contain (i) a brief clinical history summarizing the symptoms and course of the illness, (ii) a description of how the organism(s) was cultured and differentiated from closely associated organisms, and (iii) the results of susceptibility tests for the isolate(s). (Source: Clinical Microbiology Newsletter)

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9th European Nitrogen Fixation Conference

Microbiology Blog: The weblog for microbiologists. — Wed, 27 Jan 2010 16:55:00 +0100

September 6 - 10, 2010 9th European Nitrogen Fixation ConferenceGeneva, Switzerland Further informationTopics include: Applied aspects of biological nitrogen fixation; Evolution and diversity of diazotrophs and hosts; Genomics and post-genomics of diazotrophs and hosts; Interactions of proteobacteria with legumes; Interactions of diazotrophs with non-legume hosts; Novel tools and technologies to study diazotrophy; Physiology of free-living and symbiotic diazotrophs; Regulation of nitrogen fixation; Structure and function of nitrogenase.Suggested reading: Microbiology BooksFull range of books on microbiology at Microbiology Books (Source: Microbiology Blog: The weblog for microbiologists.)

Online‐Only Abstracts

Clinical Microbiology and Infection — Sun, 22 Jan 2012 02:17:31 +0100

(Source: Clinical Microbiology and Infection)

Degradation of biogenic amines by vineyard ecosystem fungi. Potential use in winemaking

Journal of Applied Microbiology — Wed, 25 Jan 2012 03:53:41 +0100

Conclusions: The study highlighted the ability of grapevine ecosystem fungi to degrade biogenic amines and their potential application for biogenic amines removal in wine.Significance and Impact of Study: The fungi extracts described in this study may be useful in winemaking to reduce the biogenic amines content of wines, thereby preventing the possible adverse effects on health in sensitive individuals and the trade and export of wine.© 2012The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology (Source: Journal of Applied Microbiology)

Modulating the immune system against fungal infections—where are we?

Clinical Microbiology and Infection — Sun, 22 Jan 2012 02:17:04 +0100

(Source: Clinical Microbiology and Infection)

Trafficking and release of the metacyclic HASPB protein in the kinetoplastid parasite Leishmania

Cellular Microbiology — Sun, 22 Jan 2012 02:11:11 +0100

SummaryProteins of the Leishmania HASPB family are only expressed in infective parasites (both extra‐ and intracellular stages) and, together with the peripheral membrane protein SHERP, are essential for parasite differentiation (metacyclogenesis) in the sand fly vector. HASPB is a “non‐classically” secreted protein, requiring N‐terminal acylation for trafficking to and exposure on the plasma membrane. Here, we use live cell imaging methods to further explore this pathway to the membrane and flagellum. Unlike HASPB trafficking in transfected mammalian cells, we find no evidence for a phosphorylation‐regulated recycling pathway in metacyclic parasites. Once at the plasma membrane, HASPB18‐GFP can undergo bidirectional movement within the inner leaflet of the membrane and on th...

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Adenosine deamination increases the survival under acidic conditions in Escherichia coli

Journal of Applied Microbiology — Sat, 28 Jan 2012 02:27:23 +0100

Conclusions: Our present results imply that adenosine was used to survive under extremely acidic conditions via the production of NH3.Significance and Impact of the Study: It has been proposed that amino acid decarboxylation is the major system for the resistance of E. coli to acidic stress. In the present study, the adenosine deamination was shown to induce the survival under acidic conditions, demonstrating that bacteria have alternative strategies to survive under acidic conditions besides amino acid decarboxylation.© 2012The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology (Source: Journal of Applied Microbiology)

Evidence of Bacillus thuringiensis Intra-Serovar Diversity Revealed by Bacillus cereus Group-Specific Repetitive Extragenic Palindromic Sequence-Based PCR Genomic Fingerprinting

Journal of Molecular Microbiology and Biotechnology — Wed, 25 Jan 2012 04:04:06 +0100

J Mol Microbiol Biotechnol 2011;21:184–190 (DOI:10.1159/000335532) (Source: Journal of Molecular Microbiology and Biotechnology)

Differential roles of pyruvate decarboxylase in aerial and embedded mycelia of the ascomycete Gibberella zeae

FEMS Microbiology Letters — Sat, 28 Jan 2012 02:20:39 +0100

In this study, we deleted all three pyruvate decarboxylase (PDC) genes, which encode enzymes that function upstream of ACS1 in the PAA pathway. Results suggest PDC1 is required for lipid accumulation in the aerial mycelia, and deletion of PDC1 resulted in highly wettable mycelia. However, the total amount of lipids in the PDC1 deletion mutants was similar to that of the wild‐type strain, likely due to compensatory lipid production processes in the embedded mycelia. PDC1 was expressed both in the aerial and embedded mycelia, whereas ACS1 was observed only in the aerial mycelia in a PDC1‐dependent manner. PDC1 is also involved in vegetative growth of embedded mycelia in G. zeae, possibly through initiating the ethanol fermentation pathway. Thus, PDC1 may function as a key metabolic enzym...

Genomics of epidemic pathogens

Clinical Microbiology and Infection — Wed, 25 Jan 2012 03:56:58 +0100

AbstractVirulence factors are thought to be responsible for the virulence capacity of pathogenic bacteria. However recently, epidemic bacteria were found to contain significantly fewer “virulence factors” than non epidemic species and some of the most dangerous epidemic bacteria, such as Mycobacteria spp., or Rickettsia spp. are reduced and contain hundreds of degraded genes. Epidemic bacteria are actually highly specialized species, characterized by allopatric speciation, that after adapting to their hosts, attempt to maintain a balance between gene gain and gene loss favouring gene loss, finally leading to a genome reduction. Recent comparative genomic studies have demonstrated that the specialization of bacteria to eukaryotic cells is associated with massive gene loss. Furthermore, ...