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Prion ProteinEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A conformational transition of the cellular prion protein (PrPC) into an aberrantly folded isoform designated scrapie prion protein (PrPSc) is the hallmark of a variety of neurodegenerative disorders collectively called prion diseases. They include Creutzfeldt-Jakob disease and Gerstmann-Stäussler-Scheinker syndrome in humans, scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle and chronic wasting disease (CWD) in free-ranging deer. In contrast to the deadly properties of misfolded PrP, PrPC seems to possess a neuroprotective activity. More-over, animal models indicated that the stress-protective activi...
Source: Microbiology Blog: The weblog for microbiologists. - November 16, 2009 Category: Microbiology Tags: Prion disease BSE PRPSc PRPC Gerstmann-Staussler-Scheinker syndrome Scrapie Bovine spongiform encephalopathy Chronic wasting disease Creutzfeldt-Jakob disease Source Type: blogs

Conference UpdateEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
December 16 - 18, 2009. Quantitative Imaging for Systems BiologyOxford, UK Further informationThe Oxford Centre for Integrative Systems Biology is hosting this 3 day conference. The conference will bring together researchers working on microscope design and single molecule detection with those using in vivo imaging techniques and those involved in quantitative image analysis and data storage. Over the 3 day meeting we will focus on the application of cutting edge microscopy techniques to biological imaging and on novel methods for the quantitative analysis of biological images.June 6 - 10, 2010 14th International Conferenc...
Source: Microbiology Blog: The weblog for microbiologists. - November 9, 2009 Category: Microbiology Tags: Conference updates Microbiology conference update conferences Source Type: blogs

Noncoding RNAs in EBVEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Epstein-Barr virus (EBV) expresses two small RNAs known as EBERs (EBV-encoded RNAs) and several microRNAs. EBERs are the most abundant viral transcript produced during latent infection by EBV in a wide variety of cell types and disease conditions. They have been demonstrated to have a variety of effects on cell growth and physiology in experiments performed in vitro and in cell culture remains to be defined. Although the abundance of EBERs in latently infected cells implies an important function, their biological role in vivo and their molecular mechanisms of action remain poorly understood. EBV microRNAs function in regu...
Source: Microbiology Blog: The weblog for microbiologists. - November 6, 2009 Category: Microbiology Tags: EBERs microRNAs Small RNAs miRNAs EBV-encoded RNAs Source Type: blogs

EBV Latent Membrane Protein 1 OncoproteinEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Latent infection membrane protein 1 (LMP1) is expressed in most malignances associated with EBV infection, has oncogene-like effects on immortalized fibroblasts, and is essential for EBV to efficiently transform the growth of resting primary B-lymphocytes into long-term autonomously proliferating lymphoblastoid cell lines. Recombinant virus, genetic, and biochemical analyses have revealed that LMP1 is a constitutively active membrane receptor that appropriates signaling adapters of the tumor necrosis factor receptor superfamily to alter cell gene expression through NF κB, mitogen-activated protein kinases, or interfe...
Source: Microbiology Blog: The weblog for microbiologists. - November 6, 2009 Category: Microbiology Tags: Oncogene LMP1 Tumor necrosis factor receptor superfamily EBV-related cancers Source Type: blogs

EBV Nuclear Antigen Family 3Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Epstein-Barr virus (EBV) infects over 90% of the world's population, and like other herpesviruses it establishes a permanent latent infection in the host. The native B-lymphocyte is the preferred target of EBV, which after differentiation into memory B-cells contains the latent reservoir of virus subsequent to the resolution of acute infection. Several malignancies have been associated with EBV infection, including nasopharyngeal carcinoma, endemic Burkitt's lymphoma, AIDS-related lymphoma and post-transplant lymphoproliferative disorder, among others. During the latent phase of infection and in EBV-associated tumors, a li...
Source: Microbiology Blog: The weblog for microbiologists. - November 6, 2009 Category: Microbiology Tags: EBNA3 Post-transplant lymphoproliferative disorder nasopharyngeal carcinoma AIDS-related lymphoma Endemic Burkitts lymphoma Source Type: blogs

Ebna-2Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Epstein-Barr virus nuclear antigen-2 (EBNA-2) plays a key role in B-cell growth transformation by initiating and maintaining the proliferation of infected B-cells upon EBV infection in vitro. EBNA-2 is one of the first viral genes expressed after virus infection. By activating viral as well as cellular target genes EBNA-2 initiates the transcription of a cascade of primary and secondary target genes, which eventually govern the activation of the resting B-cell, cell cycle entry and proliferation of the growth transformed cells. The growth transformed B-cells exhibit a phenotype reminiscent of antigen activated B-cells. In ...
Source: Microbiology Blog: The weblog for microbiologists. - November 6, 2009 Category: Microbiology Tags: Apoptotic activities Notch signalling CBF1 B-cell growth transformation Source Type: blogs

Ebna1Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
EBNA1 is the latent origin binding protein of Epstein-Barr virus and the only viral protein needed for the replication and stable persistence of EBV episomes. The contributions of EBNA1 include facilitating the initiation of DNA synthesis and ensuring the even distribution of the viral episomes to daughter cells during mitosis, a function that involves tethering the episomes to the cellular chromosomes. EBNA1 also activates the transcription of other viral latency genes important for cell immortalization and can autoregulate its own expression. In addition, EBNA1 has been found to alter the cellular environment in a number...
Source: Microbiology Blog: The weblog for microbiologists. - November 6, 2009 Category: Microbiology Source Type: blogs

Epstein-Barr Virus Leader ProteinEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Epstein-Barr virus (EBV) efficiently infects and immortalizes human B lymphocytes through expression of at least 12 viral genes, which include the EBNA-LP protein. Recent work discusses the current state of knowledge about how EBNA-LP contributes to EBV biology. EBNA-LP is an enigmatic protein comprised largely of 22 and 44 amino acid repeated sequences. Elucidation of EBNA-LP functions has been guided by identification of interacting cellular and viral proteins. The functions of these cofactors implicate EBNA-LP as a potential modulator of apoptosis, cell cycle processes, and transcriptional pathways. Recent studies have ...
Source: Microbiology Blog: The weblog for microbiologists. - November 6, 2009 Category: Microbiology Tags: Herpesviruses Apoptosis EBNA-LP EBV Leader Protein EBNA-LP protein Sp100 Source Type: blogs

Latent Epstein-Barr Virus InfectionsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In primary infection, Epstein-Barr Virus (EBV) replicates in oro-pharyngeal epithelial cells and establishes Latency III, II, and I infections in B-lymphocytes. EBV latent infection of B-lymphocytes is necessary for virus persistence, subsequent replication in epithelial cells, and release of infectious virus into saliva. EBV Latency III and II infections of B-lymphocytes, Latency II infection of oral epithelial cells, and Latency II infection of NK- or T-cell can result in malignancies, marked by uniform EBV genome presence and gene expression. Because of the marked CD4+ and CD8+ T-cell response to EBV nuclear proteins in...
Source: Microbiology Blog: The weblog for microbiologists. - November 6, 2009 Category: Microbiology Tags: EBV Latency I EBV Latency III Latent EBV Infections B-lymphocytes Source Type: blogs

Epstein-Barr VirusEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Epstein-Barr virus (EBV) is a human gamma herpes virus that is best known for being the causative agent of infectious mononucleosis in man. A fascinating feature of this virus is its ability to persist in the host and it is estimated that more than 95% of adults are carriers of the virus. Importantly, EBV can transform latently infected primary cells from healthy individuals into cancerous ones, thereby causing important human cancers such as B-cell neoplasms (e.g. Burkitt's lymphoma and Post-transplant lymphomas), certain forms of T-cell lymphoma, and some epithelial tumours (e.g. gastric carcinomas). Understanding viral ...
Source: Microbiology Blog: The weblog for microbiologists. - November 6, 2009 Category: Microbiology Tags: infectious mononucleosis EBV Post-transplant lymphoma Burkitts lymphoma Gamma herpes virus Source Type: blogs

Blastocystis Mitochondrion-like OrganellesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The organelles in Blastocystis that resemble mitochondria are an enigma as the organism is a strict anaerobe. Recent sequence analyses of the organelle genome and over 12,000 expressed sequence tags (ESTs) has given us many insights into the role these organelles play in the metabolism of the cell. The genome encodes several subunits of NADH dehydrogenase (complex I) but lacks all trace of genes for cytochrome and ATPase subunits (Complexes III-V). ESTs confirm the presence of complexes I and II, and indicate that this partial electron transport chain may lead to an alternative oxidase. The ESTs also suggest that many othe...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Mitochondrion-like Organelles Mitochondria Hydrogenosomes NADH dehydrogenase Blastocystis ATPase subunits Source Type: blogs

GiardiaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
and the other diplomonads are unique in their possession of two nuclei that are similar in appearance, DNA content, transcription, and time of replication. Trophozoites have a ploidy of four and the ploidy of cysts is eight, which in turn raises the question of how Giardia maintains homogeneity between the chromosomes of the same and opposite nuclei. Giardia has been assumed to be primitively asexual and with no means of transferring DNA between nuclei. These assumptions make it very difficult to explain the remarkably low level of allelic heterozygosity (< 0.01%) in the genome isolate, WB. However, all these assumptions ...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Giardia WB Trophozoites Diplomonads Ploidy Allelic heterozygosity Source Type: blogs

Gene Expression in Entamoeba histolyticaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Our knowledge of the functions of different structural proteins and virulence factors in the cellular organization and pathogenesis of Entamoeba histolytica has significantly increased following the introduction of various molecular techniques that enable the manipulation of gene expression. Unfortunately, to date, all the attempts to integrate exogenous DNA into the parasite's genome have failed and most methods for up- and down-regulation of gene expression have been based on the transfection of stably maintained plasmids. Down-regulation has been achieved by plasmids encoding: (i) antisense RNA, (ii) truncated or mutate...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Down-regulation of gene expression Amoebapore gene Amoebae Source Type: blogs

Entamoeba histolytica Genomic AnalysesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The sequencing of the Entamoeba histolytica genome, as well as the development of genome-wide techniques to allow study of gene expression, has led to many advances in our understanding of the biology of this parasite. Recent work used genomic technologies (DNA microarrays and proteomics) to study important aspects of amebic biology, including pathogenesis, host interaction, phagocytosis, stage conversion, responses to stressful stimuli, and mechanisms of gene regulation. These studies identify pathways involved in regulating major functions in this important human pathogen.from Anaerobic Parasitic Protozoa: Genomics and M...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Amebic biology Proteomics DNA microarrays Source Type: blogs

Cytoskeleton in Giardia and TrichomonasEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A recent publication discusses the Giardia lamblia and Trichomonas vaginalis genome projects that have brought to our understanding of the unique cytoskeletal protein profiles of these two parasites and integrates this new analysis of protein composition with recent structural and functional studies. Although both parasites are flagellated, the differences in both the structural and protein composition of their cytoskeletons are more numerous than their similarities. Consistent with general patterns across its genome, the cytoskeletal gene families in Trichomonas are greatly amplified in number, while the corresponding fam...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Microfilament proteome Cytoskeletal gene families Kinesin motor family Dynein Cytoskeleton Source Type: blogs

Actin Cytoskeleton of Entamoeba histolyticaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Host tissue invasion by E. histolytica is driven by motility and phagocytosis, which are both regulated primarily by reorganization of the actin cytoskeleton. The structural and signaling components of the actin cytoskeleton from available genomes of three Entamoeba species, E. histolytica, E.dispar and E. invadens, have been annotated manually and compared systematically. These protein families include the actin superfamily, actin nucleators, calponin-related actin-binding proteins (ABPs), gelsolin-related ABPs, myosins, small GTPases and their regulators, as well as phospholipid signaling regulators.from Anaerobic Parasi...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Entamoeba histolytica Actin nucleators Phagocytosis motility Actin superfamily E histolytica Small GTPases E dispar E invadens Source Type: blogs

Trichomonas vaginalis GenomeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The genome of Trichomonas vaginalis, the first from a parabasalid to be sequenced, was published in 2007, the culmination of a project marked by several surprises and not a little distress. The ~160 Mb genome was found to be significantly larger than first described, presenting new challenges to the standard genome sequencing pipeline.from Anaerobic Parasitic Protozoa: Genomics and Molecular BiologyFurther reading:Anaerobic Parasitic ProtozoaAcanthamoeba: Biology and PathogenesisLeishmania: After The GenomeFull range of books on microbiology at Microbiology Books (Source: Microbiology Blog: The weblog for microbiologists.)
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Trichomonas vaginalis Parabasalid Parabasalid genome Source Type: blogs

Giardia GenomeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Diplomonads are a group of mitochondrion-lacking, binucleated flagellates found in anaerobic or micro-aerophilic environments. Most research on diplomonads has focused on Giardia, which is a major cause of water-borne enteric disease in humans and other animals. The first diplomonad to have its genome sequenced was a Giardia isolate (WB) and the 11.7 million basepair genome is compact in structure and content with simplified basic cellular machineries and metabolism. Currently the genomes of several other Giardia isolates and diplomonads (the fish pathogens Spironucleus vortens and S. salmonicida) are being sequenced. from...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Spironucleus Water-borne enteric disease Giardia lamblia Diplomonads Spironucleus salmonicida Spironucleus vortens Binucleated flagellates Source Type: blogs

Entamoeba histolyticaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
is the causative agent of amoebic dysentery and liver abscess that affect millions of people annually worldwide resulting in tens of thousands deaths. Loftus et al. published an annotation of the draft genome assembly in 2005. However, subsequent identification of assembly artifacts and the availability of additional sequence and functional data made necessary a thorough revision of its entire sequence and annotation. The genome of E. histolytica has now been re-assembled and re-annotated, incorporating significant structural and functional modifications to existing gene models. The new 20 million basepair genome assembly...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Entamoeba histolytica Amoebic dysentery Liver abscess E histolytica Source Type: blogs

Anaerobic protozoa bookEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In a forthcoming book on anaerobic protozoa, internationally acclaimed researchers critically review the most important aspects of research on anaerobic parasitic protozoa, providing the first coherent picture of their genomics and molecular biology since the publication of the genomes. Chapters are written from a molecular and genomic perspective and contain speculative models upon which future research efforts can be based. Topics include: the genomes of Entamoeba histolytica, Trichomonas vaginalis, Giardia and other diplomonads; the cytoskeletons of Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis; genom...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Entamoeba histolytica Giardia lamblia Diplomonads Trichomonas vaginalis Mitochondrion-like organelles Blastocystis Source Type: blogs

Anaerobic Parasitic ProtozoaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Anaerobic parasitic protozoa cause medically and economically important diseases such as dysentery, sexually transmitted infections, and gastroenteritis that affect millions of people worldwide annually. Recently the genomes of the three key anaerobic protozoa, Trichomonas, Giardia and Entamoeba, have been determined. The availability of these genomic data and the use of post-genomic analyses have provided fascinating new insights into the biology of these important parasites. They will be important for the design of novel anti-protozoan drugs and the development of effective vaccines.from Anaerobic Parasitic Protozoa: Gen...
Source: Microbiology Blog: The weblog for microbiologists. - November 5, 2009 Category: Microbiology Tags: Anaerobic protozoa Gastroenteritis Anti-protozoan drugs Parasitic protozoa Dysentery Trichomonas Entamoeba Giardia Source Type: blogs

Lentivirus Coinfections and SuperinfectionsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The phenomenon of lentiviral superinfection, that is, infection with a second unique strain of virus after a primary viremia has already been established, is an important aspect of lentivirus biology, and is being increasingly recognized as a method for rapid emergence of new strains via the process of recombination. Though there are both host and viral barriers to simultaneous coinfection following exposure with two unique lentiviruses, it is well established in both natural and experimental systems that infection with one strain of lentivirus does not impart resistance to superinfection. Viral kinetics and dynamics of in...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Source Type: blogs

Bovine LentivirusesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Infections with the bovine lentiviruses, bovine immunodeficiency virus (BIV) or Jembrana disease virus (JDV) represent the extremes of lentivirus induced disease. BIV has a broad cell tropism and causes a mild lymphoproliferative disorder with low viral titres and no reproducible disease sequelae. JDV has a more restricted cell tropism than BIV and infects Bali cattle in Indonesia, replicating to high viral titres during an acute disease period characterized by lymph node enlargement, leucopaenia and high rectal temperatures. The similarities and differences between these two genetically and antigenically closely related v...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Tags: JDV BIV Bovine immunodeficiency virus Jembrana disease virus Source Type: blogs

Small Ruminant LentivirusesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Visna-Maedi virus (VMV) and the caprine arthritis encephalitis virus (CAEV) were considered to be specific pathogens of sheep and goats, respectively. The finding that these lentiviruses frequently cross the species barrier between sheep and goats, and vice versa, has changed our view of the epidemiology of these viruses and they are now referred to as small ruminant lentiviruses (SRLV). A brief review of the molecular epidemiology of these lentiviruses will illustrate the diffusion and intermixing of these viruses in the two target species and documented cases of double infection and recombination between VMV and CAEV...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Tags: VMV Visna-Maedi virus Caprine arthritis encephalitis virus CAEV Source Type: blogs

Equine Infectious Anemia VirusEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Equine infectious anemia virus (EIAV) is an ungulate lentivirus related to human immunodeficiency virus (HIV). Much of the understanding of lentiviral infection of macrophages comes from HIV studies that have provided insights into molecular regulation of all lentiviruses. However, numerous aspects of the life cycle of each lentivirus are unique and associated with specific pathological consequences. In vivo EIAV is primarily if not exclusively a macrophage-tropic virus. As a consequence of this targeted tropism, EIAV causes an acute and sometimes fulminant disease associated with high-titered viremia with no associated im...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Tags: EIAV Lentiviral infection Source Type: blogs

Felid Immunodeficiency VirusesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lentiviruses are widespread pathogens of primates, ungulates and felids. While the ungulate lentiviruses induce a disease state typical of a chronic inflammatory condition, the felid and primate lentiviruses induce an immunodeficiency characterised by a progressive depletion of CD4+ T helper cells. FIV infection of the domestic cat may lead to a spectrum of diseases, ranging from a rapid, acute-onset immunodeficiency to a chronic wasting disease with concomitant neuropathology and persistent recurring opportunistic infections. Here, we examine the host and viral determinants of FIV cell tropism and pathogenicity. The virus...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Tags: CD134 FIV CXCR4 CD4 T helper cells Source Type: blogs

Simian-human immunodeficiency virusEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
(SHIV) was generated as a model for acquired immunodeficiency syndrome (AIDS) in order to overcome the narrow host range of human immunodeficiency virus (HIV-1). The first-generation SHIVs were nonpathogenic but evolved to become highly pathogenic viruses. Highly pathogenic SHIVs induce a distinct disease phenotype: a massive, systemic, and irreversible depletion of CD4+ T cells occurs within weeks of infection, followed by AIDS-like clinical manifestations. During the acute phase of infection, the virus predominantly infects and destroys CD4+ T cells. As a result, macrophages become the major virus-producing cell type. V...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Tags: HIV-1 aids Macrophage tropism SHIV CXCR4 Source Type: blogs

The Macrophage and HIVEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Rapid depletion of CD4+ T-lymphocytes has been associated with a switch in HIV-1 coreceptor usage from CCR5 to CXCR4 in approximately 40 to 50% of infected individuals. However, the majority of infected individuals who progress to AIDS harbour only CCR5-dependent (R5) viral strains. HIV-1 disease progression is associated with an enhanced tropism of R5 viral strains for cells of the monocyte/macrophage lineage (enhanced M-tropism). However, the underlying molecular mechanisms contributing to enhanced M-tropism by R5 HIV-1 strains, and how HIV-1 variants with enhanced M-tropism cause CD4+ T-cell depletion in vivo are unknow...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Source Type: blogs

Restrictions to Lentiviral ReplicationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Host organisms contain numerous defenses to protect themselves against invading pathogens like lentiviruses. These defense systems include intracellular inhibitory proteins termed "restriction factors", which have recently risen to prominence with the discovery of APOBEC3 and TRIM5 cellular proteins as key factors restricting invading retroviruses in host cells. Understanding how these and other intracellular restriction factors block retroviruses is providing new insights into barriers of retroviral replication and the cross-species transmission of lentiviruses. Moreover, these restriction factors have important ramificat...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Source Type: blogs

Macrophage BiologyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Macrophages possess elaborate sensors for pathogens and have evolved complex chemically mediated interactions with other components of the immune system. Macrophage precursors differentiate into multiple end-stage specialised cell types in mammals, each suited for specific roles in homeostasis and defence. Research in macrophage biology is at a particularly exciting stage with new defence pathways still in the process of discovery. At the same time, enough is known to glimpse the complete picture that will one day be available for this staggeringly complex molecular machine which is a central organiser of immune defences. ...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Source Type: blogs

Lentivirus Tropism and DiseaseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lentiviruses are among the most intensely and extensively studied group of viruses. They are found worldwide and infect a broad array of animal species. Historically, lentiviruses have been investigated longer than any other virus group. The first viral etiology ascribed to an animal disease was a lentivirus. The diseases associated with lentiviral infections range from benign and subclinical to severely debilitating and lethal. The diverse group of viruses that compose the lentiviruses have many common and distinctive features. Among the common features is tropism for cells from the monocyte/macrophage lineage. Infection ...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Tags: Tropism Infection of macrophage Source Type: blogs

Viral infection of mononuclear phagocytesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Virus can simultaneously assemble and hide in intracellular compartments, largely free from immune attack. Interestingly, the mononuclear phagocytes are not destroyed by virus and throughout infection they still contribute to host immunity while at the same time perpetuating lentiviral dissemination. Infected mononuclear phagocytes are readily observed in lymph nodes and organs such as the lung and brain, where they produce cytotoxic mediators that contribute to the development of disease. For human immunodeficiency virus (HIV) infection functional impairment of infected mononuclear phagocytes likely accelerates immune def...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Source Type: blogs

LentivirusesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
comprise a genus of diverse viruses in the Retroviridae family which are united in their ability to infect and persist in macrophages. Infections are characterized by immune system dysfunctions following sometimes lengthy incubation periods. The viruses in this genus include primate lentiviruses such as HIV as well as animal lentiviruses including equine infectious anemia virus (EIAV). An intriguing feature of lentiviruses is their ability to hijack macrophages so that they are simultaneously involved in the dissemination and control of virus spread throughout the host, leading to disease induction and/or transmission to ...
Source: Microbiology Blog: The weblog for microbiologists. - November 4, 2009 Category: Microbiology Tags: Lentiviral-macrophage interaction Macrophage biology Source Type: blogs

Polysaccharide book reviewEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chang-Chun Ling of University of Calgary, Canada writes in ChemBioChem (2009) 10: 2539-2540:"a collection of reviews written by experts ... one of the most up-to-date and authoritative books available on topics about bacterial polysaccharides ... overall the book provides a substantial wealth of coverage ... with extensive references provided at the end of each chapter and the use of many experimental data to support scientific conclusions, I think that this book will prove to be a highly valuable resource for researchers and advanced students"Bacterial Polysaccharides: Current Innovations and Future TrendsPublisher: Caist...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: book review polysaccharides bacterial polysaccharides Source Type: blogs

Population Genetics in the Age of MetagenomicsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Microbial population genetics examines the spatial and temporal patterns of genetic variation across diverse geographic scales and ecological niches. With the arrival of molecular biological techniques, the past 40 years have seen tremendous progresses in microbial population genetics. However, in recent years, the analyses of genetic materials directly from natural environments have revolutionized our approaches and understandings of the diversity, function, and inter-relationships among microorganisms in diverse natural ecological niches (Xu, 2010). The emergence and development of this expanding new field, that of metag...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Microbial Population Genetics metagenomics Source Type: blogs

Population Genetics of Viral PathogensEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Many viral pathogens, especially those with an RNA genome, are characterized by their high mutation rates and large population sizes. These features are responsible for the high levels of genetic variation usually found in viral populations and for their rapid response to different selective challenges encountered during their infection and transmission processes. They are quantitatively and qualitatively so different from most other organisms that special models and concepts, such as the quasispecies model, have been developed to better describe the evolutionary dynamics of viral populations (Xu, 2010). Population genetic...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Viral Pathogens Phylodynamics population genetics Source Type: blogs

Population Genetics of MalariaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Genetic diversity, population structure, and evolutionary history of malaria parasites are among the key factors that will influence our ability to identify genes contributing to drug resistance, parasite development, and disease pathogenesis. These factors also have an impact on vaccine and drug development, parasite source tracking, as well as the formulation of other disease prevention and control measures. For example, a highly polymorphic parasite population will contain ample genetic diversity capable of generating drug resistance genotypes at an accelerated rate; while the presence of homogeneous parasite population...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Microbial Population Genetics Malaria Source Type: blogs

Population Genetics of Pathogenic FungiEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Common DNA-based markers are used to genotype fungi, as well as other eukaryotes. This technology is being used to elucidate the population genetics of mammalian pathogenic fungi. This exciting area of research is continually growing as the methods become more accessible and medical mycologists recognize the value of studying natural isolates of pathogenic fungi (Xu, 2010).References:Xu, J. (2010) Microbial Population Genetics. Caister Academic Press, Norfolk, UK.San-Blas, G. and Calderone, R.A. (2008) Pathogenic Fungi: Insights in Molecular Biology. Caister Academic Press, Norfolk, UK.Recommended reading:Medical mycologyF...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Pathogenic fungi Source Type: blogs

Population Genetics of MicroalgaeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Algae are a highly diverse group of protists, ranging from simple, unicellular organisms to complex, multicellular entities with a range of differentiated tissues and distinct organs. They are found among diverse aquatic ecosystems and play important roles by supplying carbon and energy as well as providing habitat to other members of the biological communities. Some algae cause significant environmental and health problems. However, despite their importance, relatively little is known about this group of organisms. A recent review Xu, 2010 summarizes the population genetic analyses of three algal groups: the dinoflagellat...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Microalgae Source Type: blogs

Population Genetics of CyanobacteriaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cyanobacteria are a group of ecologically diverse photosynthetic bacteria. Because niche differentiation is ultimately the product of differences among individuals within populations, understanding the evolutionary origins of this diversity ultimately requires a population genetics perspective. Recent work has elucidated the mechanisms that generate variation in cyanobacteria, the distribution of this diversity and its potential functional importance, and has suggested a population genomics approach to address fundamental questions regarding the nature of adaptive variation and niche differentiation in Cyanobacteria. (Xu, ...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: cyanobacteria population genetics Photosynthetic bacteria Source Type: blogs

Population Genetics of RhizobiaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Symbiotic nitrogen-fixing Rhizobia are of global significance, both in terms of their ecological relationships and their importance as an environmentally benign source of nitrogen for crop plants. These bacteria are capable of forming mutualistic relationships with a variety of legume hosts, where they convert atmospheric nitrogen to ammonia that is used to help meet the nitrogen needs of the host plant (Xu, 2010). The results of recent studies have revealed several important insights, including the existence of extensive diversity within, as well as significant genetic differentiation between local and regional population...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Rhizobia Nitrogen-fixing Rhizobial populations Source Type: blogs

Population Genetics of Human Pathogenic BacteriaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Population genetics examine variation in genes among a group of strains of a particular species. Its major theme is to look at how different environmental factors and selective pressures can affect the distribution of genes and alleles. Yersinia pestis was employed (Xu, 2010) as an example to illustrate how the techniques are used for population genetic studies and how the achievements of these kinds of studies can be used for rapid identification and tracing the origin of pathogenic bacteria. New emerging techniques, including high throughput sequencing technologies, will give us unprecedented opportunities to understand ...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Microbial Population Genetics Source Type: blogs

Horizontal Gene TransferEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Horizontal gene transfer, as a major force in shaping bacterial gene content, has gained incredible attention over the last decade. Along with the fast growing bacterial genome sequence data, there have been an increasingly large number of studies focused on horizontal gene transfer. The studies have been gradually transformed from identifying individual genes that have been horizontally transferred to assessing the general patterns of horizontal gene transfer and evaluating the systematic consequences of massive gene transfers. The rates of gene transfers have been measured by various methods such as parsimony and maximum...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Phylogenetic methods Horizontal Gene Transfer in Bacteria Source Type: blogs

Microbial GenomicsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Microbes are ubiquitous in the world in which we live. With the development of high throughput DNA sequencing technology, there has been an explosion of DNA sequence data on microbes. The major aim of future microbial genomics will be to identify the functional significances of individual gene and genomic fragments and to use the information to help improve human health and promote our society development. One current major undertaking to understand genomic information is the comparative analyses between genomes that are not only distantly related, but also closely related ones. Such comparative analyses between genomes th...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: DNA sequencing technology Comparative Microbial Genomics Source Type: blogs

Microbial SystematicsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The higher taxonomic groups within prokaryotes are presently distinguished mainly on the basis of their branching in phylogenetic trees. In most cases, no molecular, biochemical or physiological characteristics are known that are uniquely shared by species from these groups. Analyses of genome sequences are leading to discovery of novel molecular characteristics that are specific for different groups of bacteria and archaea and provide more precise means for identifying and circumscribing these groups of microbes in clear molecular terms and for understanding their evolution (Xu, 2010).References:Xu, J. (2010) Microbial Po...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Phylogenetic trees Microbial evolution Source Type: blogs

Microbial population geneticsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
is a rapidly advancing field of investigation with relevance to many areas of science. The subject encompasses theoretical issues such as the origins and evolution of species, sex and recombination. Population genetics lays the foundations for tracking the origin and evolution of antibiotic resistance and deadly infectious pathogens and is also an essential tool in the utilization of beneficial microbes.References:Xu, J. (2010) Microbial Population Genetics. Caister Academic Press, Norfolk, UK.Full range of books on microbiology at Microbiology Books (Source: Microbiology Blog: The weblog for microbiologists.)
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: antibiotic resistance Evolution of species population genetics Source Type: blogs

Relapsing feverEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
is caused by several species of Borrelia, all but one of which are transmitted from reservoir animals to humans by soft (argasid) ticks. The exception is B. recurrentis, which is transmitted from one human to another by the body louse and, under certain conditions, may cause large epidemics. Relapsing fever Borrelia species have a number of properties that facilitate invasion and dissemination in the mammalian host; these include neurotropism and adhesiveness for erythrocytes and platelets. But their most characteristic pathogenetic feature is multiphasic antigenic variation. Surface-exposed lipoproteins largely determine...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Argasid ticks B. recurrentis Body louse Source Type: blogs

Pathobiology of Lyme Disease BorreliaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lyme disease Borrelia are host-dependent, tick-transmitted, invasive, nontoxigenic, persistent pathogens that cause disease in humans and other mammals primarily through the induction of inflammatory reactions. During transmission from the infected tick, the bacteria undergo dramatic changes in gene expression, resulting in adaptation to the mammalian environment. (Samuels and Radolf, 2010)Expression of outer surface protein C (OspC) is essential during these early stages of colonization, although the mechanism by which OspC promotes spirochetal infectivity is unknown. Organisms multiply and spread locally and induce an in...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Outer surface protein C Pathobiology Lyme disease Tick-transmitted infections Borrelial proteins Source Type: blogs

Metabolism and Physiology of BorreliaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Energy extracted from the fermentation of a few simple sugars fuels the key biochemical pathways and metabolic systems that are the underpinning of the physiology of Borrelia and also energizes a V-type ATPase (V-ATPase). This establishes a membrane potential that drives motility and the transport of most solutes. After transport, metabolites and biochemical intermediates, such as simple sugars, fatty acids, purines and pyrimidines, peptides and metals ions, are chemically utilized and/or modified to provide an intracellular pool of compounds necessary for protein, nucleic acid, membrane and cell wall biosynthesis. The ext...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Metabolism of Borrelia Physiology of Borrelia Source Type: blogs

BorreliaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The genus Borrelia, in the spirochete phylum, is not closely related to any other bacteria and has a highly unusual genome composed of a linear chromosome and multiple circular and linear plasmids that appear to be in a constant state of rearrangement, recombination, and deletion. The determination of the genome sequence of Borrelia strains has facilitated tremendous advances in understanding this genus at the molecular and cellular level as well as the pathogenesis of Lyme disease and relapsing fever. In recent years there has been an explosion of new insights into the molecular biology, genetics, physiology, and ecology ...
Source: Microbiology Blog: The weblog for microbiologists. - November 3, 2009 Category: Microbiology Tags: Spirochete phylum B. burgdorferi borrelia Lyme borreliosis Source Type: blogs