Complete genome sequence of Vulcanisaeta distributa type strain (IC-017)

Vulcanisaeta distributa Itoh et al. 2002 belongs to the family Thermoproteaceae in the phylum Crenarchaeota. The genus Vulcanisaeta is characterized by a global distribution in hot and acidic springs. This is the first genome sequence from a member of the genus Vulcanisaeta and seventh genome sequence in the family Thermoproteaceae. The 2,374,137 bp long genome with its 2,544 protein-coding and 49 RNA genes is a part of the Genomic Encyclopedia of Bacteriaand Archaea project.     

Complete genome sequence of Arcanobacterium haemolyticum type strain (11018)

Arcanobacterium haemolyticum (ex MacLean et al. 1946) Collins et al. 1983 is the type species of the genus Arcanobacterium, which belongs to the family Actinomycetaceae. The strain is of interest because it is an obligate parasite of the pharynx of humans and farm animal; occasionally, it causes pharyngeal or skin lesions. It is a Gram-positive, nonmotile and non-sporulating bacterium. The strain described in this study was isolated from infections amongst American soldiers of certain islands of the North and West Pacific. This is the first completed sequence of a member of the genus Arcanobacterium and the ninth type strain genome from the family Actinomycetaceae. The 1,986,154 bp long genome with its 1,821 protein-coding and 64 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.     

An essential tyrosine phosphatase homolog regulates cell separation, outer membrane integrity, and morphology in Caulobacter crescentus

Although reversible phosphorylation on tyrosine residues regulates the activity of many eukaryotic proteins, there are few examples of this type of regulation in bacteria. We have identified the first essential tyrosine phosphatase homolog in a bacterium, Caulobacter crescentus CtpA. ctpA mutants with altered active-site residues are nonviable, and depletion of CtpA yields chains of cells with blebbed outer membranes, linked by unresolved peptidoglycan. CtpA overexpression reduces cell curvature in a manner similar to deleting the intermediate filament protein crescentin, but it does not disrupt crescentin localization or membrane attachment. Although it has no obvious signal sequence or transmembrane-spanning domains, CtpA associates with the Caulobacter inner membrane. Immunolocalization experiments suggest that CtpA accumulates at the division site during the last quarter of the cell cycle. We propose that CtpA dephosphorylates one or more proteins involved in peptidoglycan biosynthesis or remodeling, which in turn affect cell separation, cell envelope integrity, and vibrioid morphology.     

Genome sequence of "Candidatus Frankia datiscae" Dg1, the uncultured microsymbiont from nitrogen-fixing root nodules of the dicot Datisca glomerata

Members of the noncultured clade of Frankia enter into root nodule symbioses with actinorhizal species from the orders Cucurbitales and Rosales. We report the genome sequence of a member of this clade originally from Pakistan but obtained from root nodules of the American plant Datisca glomerata without isolation in culture.     

Microbial synthesis of gold nanoparticles using the fungus <Emphasis Type="Italic">Penicillium brevicompactum</Emphasis> and their cytotoxic effects against mouse mayo blast cancer C<Subscript>2</Subscript>C<Subscript>12</Subscript> cells

Microorganisms, their cell filtrates, and live biomass have been utilized for synthesizing various gold nanoparticles. The shape, size, stability as well as the purity of the bio synthesized nanoparticles become very essential for application purpose. In the present study, gold nanoparticles have been synthesized from the supernatant, live cell filtrate, and biomass of the fungus Penicillium brevicompactum. The fungus has been grown in potato dextrose broth which is also found to synthesize gold nanoparticles. The size of the particles has been investigated by Bio-TEM before purification, following purification and after storing the particles for 3 months under refrigerated condition. Different characterization techniques like X-ray diffraction, Fourier transform infrared spectroscopy, and UV–visible spectroscopy have been used for analysis of the particles. The effect of reaction parameters such as pH and concentration of gold salt have also been monitored to optimize the morphology and dispersity of the synthesized gold nanoparticles. A pH range of 5 to 8 has favored the synthesis process whereas increasing concentration of gold salt (beyond 2 mM) has resulted in the formation of bigger sized and aggregated nanoparticles. Additionally, the cytotoxic nature of prepared nanoparticles has been analyzed using mouse mayo blast cancer C₂C₁₂ cells at different time intervals (24, 48, and 72 h) of incubation period. The cells are cultivated in Dulbecco’s modified Eagle’s medium supplemented with fetal bovine serum with antibiotics (streptopenicillin) at 37°C in a 5% humidified environment of CO₂. The medium has been replenished every other day, and the cells are subcultured after reaching the confluence. The viability of the cells is analyzed with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide method.     

A Genomewide Overexpression Screen Identifies Genes Involved in the Phosphatidylinositol 3-Kinase Pathway in the Human Protozoan Parasite Entamoeba histolytica

Entamoeba histolytica is a protozoan parasite that causes amoebic dysentery and liver abscess. E. histolytica relies on motility, phagocytosis, host cell adhesion, and proteolysis of extracellular matrix for virulence. In eukaryotic cells, these processes are mediated in part by phosphatidylinositol 3-kinase (PI3K) signaling. Thus, PI3K may be critical for virulence. We utilized a functional genomics approach to identify genes whose products may operate in the PI3K pathway in E. histolytica. We treated a population of trophozoites that were overexpressing genes from a cDNA library with a near-lethal dose of the PI3K inhibitor wortmannin. This screen was based on the rationale that survivors would be overexpressing gene products that directly or indirectly function in the PI3K pathway. We sequenced the overexpressed genes in survivors and identified a cDNA encoding a Rap GTPase, a protein previously shown to participate in the PI3K pathway. This supports the validity of our approach. Genes encoding a coactosin-like protein, EhCoactosin, and a serine-rich E. histolytica protein (SREHP) were also identified. Cells overexpressing EhCoactosin or SREHP were also less sensitive to a second PI3K inhibitor, {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002. This corroborates the link between these proteins and PI3K. Finally, a mutant cell line with an increased level of phosphatidylinositol (3,4,5)-triphosphate, the product of PI3K activity, exhibited increased expression of SREHP and EhCoactosin. This further supports the functional connection between these proteins and PI3K in E. histolytica. To our knowledge, this is the first forward-genetics screen adapted to reveal genes participating in a signal transduction pathway in this pathogen.     

The Central Role of cAMP in Regulating Plasmodium falciparum Merozoite Invasion of Human Erythrocytes

All pathogenesis and death associated with Plasmodium falciparum malaria is due to parasite-infected erythrocytes. Invasion of erythrocytes by P. falciparum merozoites requires specific interactions between host receptors and parasite ligands that are localized in apical organelles called micronemes. Here, we identify cAMP as a key regulator that triggers the timely secretion of microneme proteins enabling receptor-engagement and invasion. We demonstrate that exposure of merozoites to a low K⁺ environment, typical of blood plasma, activates a bicarbonate-sensitive cytoplasmic adenylyl cyclase to raise cytosolic cAMP levels and activate protein kinase A, which regulates microneme secretion. We also show that cAMP regulates merozoite cytosolic Ca²⁺ levels via induction of an Epac pathway and demonstrate that increases in both cAMP and Ca²⁺ are essential to trigger microneme secretion. Our identification of the different elements in cAMP-dependent signaling pathways that regulate microneme secretion during invasion provides novel targets to inhibit blood stage parasite growth and prevent malaria.     

Serum Metabolomic Response of Myasthenia Gravis Patients to Chronic Prednisone Treatment

Prednisone is often used for the treatment of autoimmune and inflammatory diseases but they suffer from variable therapeutic responses and significant adverse effects. Serum biological markers that are modulated by chronic corticosteroid use have not been identified. Myasthenia gravis is an autoimmune neuromuscular disorder caused by antibodies directed against proteins present at the post-synaptic surface of neuromuscular junction resulting in weakness. The patients with myasthenia gravis are primarily treated with prednisone. We analyzed the metabolomic profile of serum collected from patients prior to and after 12 weeks of prednisone treatment during a clinical trial. Our aim was to identify metabolites that may be treatment responsive and be evaluated in future studies as potential biomarkers of efficacy or adverse effects. Ultra-performance liquid chromatography coupled with electro-spray quadrupole time of flight mass spectrometry was used to obtain comparative metabolomic and lipidomic profile. Untargeted metabolic profiling of serum showed a clear distinction between pre- and post- treatment groups. Chronic prednisone treatment caused upregulation of membrane associated glycerophospholipids: phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, 1, 2-diacyl-sn glycerol 3 phosphate and 1-Acyl-sn-glycero-3-phosphocholine. Arachidonic acid (AA) and AA derived pro-inflammatory eicosanoids such as 18-carboxy dinor leukotriene B4 and 15 hydroxyeicosatetraenoic acids were reduced. Perturbations in amino acid, carbohydrate, vitamin and lipid metabolism were observed. Chronic prednisone treatment caused increase in membrane associated glycerophospholipids, which may be associated with certain adverse effects. Decrease of AA and AA derived pro-inflammatory eicosanoids demonstrate that immunosuppression by corticosteroid is via suppression of pro-inflammatory pathways. The study identified metabolomic fingerprints that can now be validated as prednisone responsive biomarkers for the improvement in diagnostic accuracy and prediction of therapeutic outcome.     

Combining Cationic Liposomal Delivery with MPL-TDM for Cysteine Protease Cocktail Vaccination against Leishmania donovani : Evidence for Antigen Synergy and Protection

BackgroundWith the paucity of new drugs and HIV co-infection, vaccination remains an unmet research priority to combat visceral leishmaniasis (VL) requiring strong cellular immunity. Protein vaccination often suffers from low immunogenicity and poor generation of memory T cells for long-lasting protection. Cysteine proteases (CPs) are immunogenic proteins and key mediators of cellular functions in Leishmania. Here, we evaluated the vaccine efficacies of CPs against VL, using cationic liposomes with Toll like receptor agonists for stimulating host immunity against L. donovani in a hamster model.Conclusion/SignificanceThe present study is the first report of a comparative efficacy of leishmanial CPs and their cocktail using liposomal formulation with MPL-TDM against L. donovani. The level of protection attained has not been reported for any other subcutaneous single or polyprotein vaccination against VL.     

Genome sequence of the Listia angolensis microsymbiont Microvirga lotononidis strain WSM3557T

Microvirga lotononidis is a recently described species of root-nodule bacteria that is an effective nitrogen- (N₂) fixing microsymbiont of the symbiotically specific African legume Listia angolensis (Welw. ex Bak.) B.-E. van Wyk & Boatwr. M. lotononidis possesses several properties that are unusual in root-nodule bacteria, including pigmentation and the ability to grow at temperatures of up to 45°C. Strain WSM3557^T is an aerobic, motile, Gram-negative, non-spore-forming rod isolated from a L. angolensis root nodule collected in Chipata, Zambia in 1963. This is the first report of a complete genome sequence for the genus Microvirga. Here we describe the features of Microvirga lotononidis strain WSM3557^T, together with genome sequence information and annotation. The 7,082,538 high-quality-draft genome is arranged in 18 scaffolds of 104 contigs, contains 6,956 protein-coding genes and 84 RNA-only encoding genes, and is one of 20 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Community Sequencing Program.