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Articles 1 - 20 of 20
Full-Text Articles in Medicine and Health Sciences
Hemocyte Differentiation Mediates The Mosquito Late-Phase Immune Response Against Plasmodium In Anopheles Gambiae, Ryan C. Smith, Carolina Barillas-Mury, Marcelo Jacobs-Lorena
Hemocyte Differentiation Mediates The Mosquito Late-Phase Immune Response Against Plasmodium In Anopheles Gambiae, Ryan C. Smith, Carolina Barillas-Mury, Marcelo Jacobs-Lorena
Ryan C. Smith
Plasmodium parasites must complete development in the mosquito vector for transmission to occur. The mosquito innate immune response is remarkably efficient in limiting parasite numbers. Previous work has identified a LPS-induced TNFα transcription factor (LITAF)-like transcription factor, LITAF-like 3 (LL3), which significantly influences parasite numbers. Here, we demonstrate that LL3 does not influence invasion of the mosquito midgut epithelium or ookinete-to-oocyst differentiation but mediates a late-phase immune response that decreases oocyst survival. LL3 expression in the midgut and hemocytes is activated by ookinete midgut invasion and is independent of the mosquito microbiota, suggesting that LL3 may be a component of …
Large Interdomain Rearrangement Triggered By Suppression Of Micro- To Millisecond Dynamics In Bacterial Enzyme I, Vincenzo Venditti, Vitali Tugarinov, Charles D. Schwieters, Alexander Grishaev, G. Marius Clore
Large Interdomain Rearrangement Triggered By Suppression Of Micro- To Millisecond Dynamics In Bacterial Enzyme I, Vincenzo Venditti, Vitali Tugarinov, Charles D. Schwieters, Alexander Grishaev, G. Marius Clore
Vincenzo Venditti
Enzyme I (EI), the first component of the bacterial phosphotransfer signal transduction system, undergoes one of the largest substrate-induced interdomain rearrangements documented to date. Here we characterize the perturbations generated by two small molecules, the natural substrate phosphoenolpyruvate and the inhibitor a-ketoglutarate, on the structure and dynamics of EI using NMR, small-angle X-ray scattering and biochemical techniques. The results indicate unambiguously that the open-to-closed conformational switch of EI is triggered by complete suppression of micro- to millisecond dynamics within the C-terminal domain of EI. Indeed, we show that a ligand-induced transition from a dynamic to a more rigid conformational state …
Immunization Against A Merozoite Sheddase Promotes Multiple Invasion Of Red Blood Cells And Attenuates Plasmodium Infection In Mice, Ryan C. Smith, Daisy D. Colón-López, Jürgen Bosch
Immunization Against A Merozoite Sheddase Promotes Multiple Invasion Of Red Blood Cells And Attenuates Plasmodium Infection In Mice, Ryan C. Smith, Daisy D. Colón-López, Jürgen Bosch
Ryan C. Smith
Subtilisin-like protease 2 (SUB2) is a conserved serine protease utilized by Plasmodium parasites as a surface sheddase required for successful merozoite invasion of host red blood cells and has been implicated in ookinete invasion of the mosquito midgut. To determine if SUB2 is a suitable vaccine target to interfere with malaria parasite development, the effects of SUB2-immunization on the Plasmodium life cycle were examined in its vertebrate and invertebrate hosts. Swiss Webster mice were immunized with SUB2 peptides conjugated to Keyhole limpet hemocyanin (KLH) or KLH alone, and then challenged with Plasmodium berghei. To determine the effects of immunization on …
A Nmr Experiment For Simultaneous Correlations Of Valine And Leucine/Isoleucine Methyls With Carbonyl Chemical Shifts In Proteins, Vitali Tugarinov, Vincenzo Venditti, G. Marius Clore
A Nmr Experiment For Simultaneous Correlations Of Valine And Leucine/Isoleucine Methyls With Carbonyl Chemical Shifts In Proteins, Vitali Tugarinov, Vincenzo Venditti, G. Marius Clore
Vincenzo Venditti
A methyl-detected ‘out-and-back’ NMR experiment for obtaining simultaneous correlations of methyl resonances of valine and isoleucine/leucine residues with backbone carbonyl chemical shifts, SIM-HMCM(CGCBCA)CO, is described. The developed pulse-scheme serves the purpose of convenience in recording a single data set for all Ileδ1, Leuδ and Valγ (ILV) methyl positions instead of acquiring two separate spectra selective for valine or leucine/isoleucine residues. The SIM-HMCM(CGCBCA)CO experiment can be used for ILV methyl assignments in moderately sized protein systems (up to ~100 kDa) where the backbone chemical shifts of 13Cα, 13Cβ and 13CO are known from prior NMR studies and where some losses in …
Transgenic Mosquitoes Expressing A Phospholipase A(2) Gene Have A Fitness Advantage When Fed Plasmodium Falciparum-Infected Blood, Ryan C. Smith, Christopher Kizito, Jason L. Rasgon, Marcelo Jacobs-Lorena
Transgenic Mosquitoes Expressing A Phospholipase A(2) Gene Have A Fitness Advantage When Fed Plasmodium Falciparum-Infected Blood, Ryan C. Smith, Christopher Kizito, Jason L. Rasgon, Marcelo Jacobs-Lorena
Ryan C. Smith
Genetically modified mosquitoes have been proposed as an alternative strategy to reduce the heavy burden of malaria. In recent years, several proof-of-principle experiments have been performed that validate the idea that mosquitoes can be genetically modified to become refractory to malaria parasite development. We have created two transgenic lines of Anophelesstephensi, a natural vector of Plasmodium falciparum, which constitutively secrete a catalytically inactive phospholipase A2 (mPLA2) into the midgut lumen to interfere with Plasmodium ookinete invasion. Our experiments show that both transgenic lines expressing mPLA2 significantly impair the development of rodent malaria parasites, but only one line impairs the development …
Enterobacter-Activated Mosquito Immune Responses To Plasmodium Involve Activation Of Srpn6 In Anopheles Stephensi, Ryan C. Smith, Abraham G. Eappen, Marcelo Jacobs-Lorena
Enterobacter-Activated Mosquito Immune Responses To Plasmodium Involve Activation Of Srpn6 In Anopheles Stephensi, Ryan C. Smith, Abraham G. Eappen, Marcelo Jacobs-Lorena
Ryan C. Smith
Successful development of Plasmodium in the mosquito is essential for the transmission of malaria. A major bottleneck in parasite numbers occurs during midgut invasion, partly as a consequence of the complex interactions between the endogenous microbiota and the mosquito immune response. We previously identified SRPN6 as an immune component which restricts Plasmodium berghei development in the mosquito. Here we demonstrate that SRPN6 is differentially activated by bacteria in Anopheles stephensi, but only when bacteria exposure occurs on the lumenal surface of the midgut epithelium. Our data indicate that AsSRPN6 is strongly induced following exposure to Enterobacter cloacae, a common component …
Structural Basis For Enzyme I Inhibition By Α-Ketoglutarate, Vincenzo Venditti, Rodolfo Ghirlando, G. Marius Clore
Structural Basis For Enzyme I Inhibition By Α-Ketoglutarate, Vincenzo Venditti, Rodolfo Ghirlando, G. Marius Clore
Vincenzo Venditti
Creating new bacterial strains in which carbon and nitrogen metabolism are uncoupled is potentially very useful for optimizing yields of microbial produced chemicals from renewable carbon sources. However, the mechanisms that balance carbon and nitrogen consumption in bacteria are poorly understood. Recently, α-ketoglutarate (αKG), the carbon substrate for ammonia assimilation, has been observed to inhibit Escherichia coli enzyme I (EI), the first component of the bacterial phosphotransferase system (PTS), thereby providing a direct biochemical link between central carbon and nitrogen metabolism. Here we investigate the EI-αKG interaction by NMR and enzymatic assays. We show that αKG binds with a KD …
Structure, Dynamics And Biophysics Of The Cytoplasmic Protein–Protein Complexes Of The Bacterial Phosphoenolpyruvate: Sugar Phosphotransferase System, Vincenzo Venditti
Structure, Dynamics And Biophysics Of The Cytoplasmic Protein–Protein Complexes Of The Bacterial Phosphoenolpyruvate: Sugar Phosphotransferase System, Vincenzo Venditti
Vincenzo Venditti
The bacterial phosphotransferase system (PTS) couples phosphoryl transfer, via a series of bimolecular protein–protein interactions, to sugar transport across the membrane. The multitude of complexes in the PTS provides a paradigm for studying protein interactions, and for understanding how the same binding surface can specifically recognize a diverse array of targets. Fifteen years of work aimed at solving the solution structures of all soluble protein–protein complexes of the PTS has served as a test bed for developing NMR and integrated hybrid approaches to study larger complexes in solution and to probe transient, spectroscopically invisible states, including encounter complexes. We review …
Regulation Of Anti-Plasmodium Immunity By A Litaf-Like Transcription Factor In The Malaria Vector Anopheles Gambiae, Ryan C. Smith, Abraham G. Eappen, Andrea J. Radtke, Marcelo Jacobs-Lorena
Regulation Of Anti-Plasmodium Immunity By A Litaf-Like Transcription Factor In The Malaria Vector Anopheles Gambiae, Ryan C. Smith, Abraham G. Eappen, Andrea J. Radtke, Marcelo Jacobs-Lorena
Ryan C. Smith
The mosquito is the obligate vector for malaria transmission. To complete its development within the mosquito, the malaria parasite Plasmodium must overcome the protective action of the mosquito innate immune system. Here we report on the involvement of the Anopheles gambiae orthologue of a conserved component of the vertebrate immune system, LPS-induced TNFα transcription factor (LITAF), and its role in mosquito anti-Plasmodium immunity. An. gambiae LITAF-like 3 (LL3) expression is up-regulated in response to midgut invasion by both rodent and human malaria parasites. Silencing of LL3 expression greatly increases parasite survival, indicating that LL3 is part of an anti-Plasmodium defense …
What Is The Risk For Metabolic Syndrome In Police Officers?, Warren D. Franke
What Is The Risk For Metabolic Syndrome In Police Officers?, Warren D. Franke
Warren D Franke
The report by Jayakrishnan and colleagues in this Journal is noteworthy since it provides an assessment of the presence of the metabolic syndrome and related cardiovascular risk factors in one of the largest, if not the largest, cohort of police officers to date. Two aspects of this research especially warrant comment.
The Use Of A Ditopic Gd(Iii) Paramagnetic Probe For Investigating Α-Bungarotoxin Surface Accessibility, Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, Mauro Botta, Gianluca Croce, Angela Pui-Ling Tong, Wing-Talk Wong, Neri Niccolai
The Use Of A Ditopic Gd(Iii) Paramagnetic Probe For Investigating Α-Bungarotoxin Surface Accessibility, Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, Mauro Botta, Gianluca Croce, Angela Pui-Ling Tong, Wing-Talk Wong, Neri Niccolai
Vincenzo Venditti
Protein surface accessibility is a critical parameter which drives all intermolecular interaction processes. In this respect a big deal of information has been derived by analyzing paramagnetic perturbation profiles obtained from NMR protein spectra, particularly in the case that the effects due to different soluble paramagnets can be compared. Here Gd2L7, a neutral ditopic paramagnetic NMR probe, has been characterized in terms of structure and relaxivity and its paramagnetic perturbations on α-bungarotoxin CαH signals in 1H–13C HSQC (heteronuclear single quantum coherence) spectra have been analyzed. Then, these signal attenuations have been compared with the ones previously obtained in the presence …
An Efficient Protocol For Incorporation Of An Unnatural Amino Acid In Perdeuterated Recombinant Proteins Using Glucose-Based Media, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore
An Efficient Protocol For Incorporation Of An Unnatural Amino Acid In Perdeuterated Recombinant Proteins Using Glucose-Based Media, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore
Vincenzo Venditti
The in vivo incorporation of unnatural amino acids into proteins is a well-established technique requiring an orthogonal tRNA/aminoacyl-tRNA synthetase pair specific for the unnatural amino acid that is incorporated at a position encoded by a TAG amber codon. Although this technology provides unique opportunities to engineer protein structures, poor protein yields are usually obtained in deuterated media, hampering its application in the protein NMR field. Here, we describe a novel protocol for incorporating unnatural amino acids into fully deuterated proteins using glucose-based media (which are relevant to the production, for example, of amino acid-specific methyl-labeled proteins used in the study …
Conformational Selection And Substrate Binding Regulate The Monomer/Dimer Equilibrium Of The C-Terminal Domain Of Escherichia Coli Enzyme I, Vincenzo Venditti, G. Marius Clore
Conformational Selection And Substrate Binding Regulate The Monomer/Dimer Equilibrium Of The C-Terminal Domain Of Escherichia Coli Enzyme I, Vincenzo Venditti, G. Marius Clore
Vincenzo Venditti
The bacterial phosphotransferase system (PTS) is a signal transduction pathway that couples phosphoryl transfer to active sugar transport across the cell membrane. The PTS is initiated by the binding of phosphoenolpyruvate (PEP) to the C-terminal domain (EIC) of enzyme I (EI), a highly conserved protein that is common to all sugar branches of the PTS. EIC exists in a dynamic monomer/dimer equilibrium that is modulated by ligand binding and is thought to regulate the overall PTS. Isolation of EIC has proven challenging, and conformational dynamics within the EIC domain during the catalytic cycle are still largely unknown. Here, we present …
Phaseolus Beans: Impact On Glycaemic Response And Chronic Disease Risk In Human Subjects, Andrea M. Hutchins, Donna M. Winham, Sharon V. Thompson
Phaseolus Beans: Impact On Glycaemic Response And Chronic Disease Risk In Human Subjects, Andrea M. Hutchins, Donna M. Winham, Sharon V. Thompson
Donna Winham
Consumption of Phaseolus vulgaris bean species such as pinto, black, navy or kidney may be beneficial in the prevention and treatment of chronic diseases. In particular, conditions that are promoted by increased glycaemic stress (hyperglycaemia and hyperinsulinaemia) including diabetes, CVD and cancer seem to be reduced in individuals who eat more of these beans. The present paper discusses the influence of P. vulgaris species on glycaemic response and the impact that relationship may have on the risk of developing diabetes, CVD and cancer.
Automated Sequence- And Stereo-Specific Assignment Of Methyl-Labeled Proteins By Paramagnetic Relaxation And Methyl–Methyl Nuclear Overhauser Enhancement Spectroscopy, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore
Automated Sequence- And Stereo-Specific Assignment Of Methyl-Labeled Proteins By Paramagnetic Relaxation And Methyl–Methyl Nuclear Overhauser Enhancement Spectroscopy, Vincenzo Venditti, Nicolas L. Fawzi, G. Marius Clore
Vincenzo Venditti
Methyl-transverse relaxation optimized spectroscopy is rapidly becoming the preferred NMR technique for probing structure and dynamics of very large proteins up to ~1 MDa in molecular size. Data interpretation, however, necessitates assignment of methyl groups which still presents a very challenging and time-consuming process. Here we demonstrate that, in combination with a known 3D structure, paramagnetic relaxation enhancement (PRE), induced by nitroxide spin-labels incorporated at only a few surface-exposed engineered cysteines, provides fast, straightforward and robust access to methyl group resonance assignments, including stereoassignments for the methyl groups of leucine and valine. Neither prior assignments, including backbone assignments, for the …
A Structurally Driven Analysis Of Thiol Reactivity In Mammalian Albumins, Ottavia Spiga, Domenico Summa, Simone Cirri, Andrea Bernini, Vincenzo Venditti, Matteo De Chiara, Raffaella Priora, Simona Frosail, Antonios Margaritis, Danila Di Giuseppe, Paolo Di Simplicio, Neri Niccolai
A Structurally Driven Analysis Of Thiol Reactivity In Mammalian Albumins, Ottavia Spiga, Domenico Summa, Simone Cirri, Andrea Bernini, Vincenzo Venditti, Matteo De Chiara, Raffaella Priora, Simona Frosail, Antonios Margaritis, Danila Di Giuseppe, Paolo Di Simplicio, Neri Niccolai
Vincenzo Venditti
Understanding the structural basis of protein redox activity is still an open question. Hence, by using a structural genomics approach, different albumins have been chosen to correlate protein structural features with the corresponding reaction rates of thiol exchange between albumin and disulfide DTNB. Predicted structures of rat, porcine, and bovine albumins have been compared with the experimentally derived human albumin. High structural similarity among these four albumins can be observed, in spite of their markedly different reactivity with DTNB. Sequence alignments offered preliminary hints on the contributions of sequence-specific local environments modulating albumin reactivity. Molecular dynamics simulations performed on experimental …
Alfp: Identifying Issues In Lymphoedema In Hte Us, Jane Armer, Joseph Feldman, Mei Fu, Nicole Stout, Bonnie Lasinski, Catherine Tuppo, Marcia Beck, Julie Rodrick, Robin Shook, Pierre Gonon, Constance Brooks, Christine Moffatt, Bob Stewart, Janice Cormier
Alfp: Identifying Issues In Lymphoedema In Hte Us, Jane Armer, Joseph Feldman, Mei Fu, Nicole Stout, Bonnie Lasinski, Catherine Tuppo, Marcia Beck, Julie Rodrick, Robin Shook, Pierre Gonon, Constance Brooks, Christine Moffatt, Bob Stewart, Janice Cormier
Robin Shook
The American Lymphedema Framework Project (ALFP) is a national initiative introduced in 2008 to improve the management of lymphoedema (LE) and related disorders in the United States. A National Stakeholders Conference was held in March 2009 to share perspectives on the current state of LE, establish priority issues, and recommend actions to move the field forward.
Measuring The Dynamic Surface Accessibility Of Rna With The Small Paramagnetic Molecule Tempol, Vincenzo Venditti, Neri Niccolai, Samuel E. Butcher
Measuring The Dynamic Surface Accessibility Of Rna With The Small Paramagnetic Molecule Tempol, Vincenzo Venditti, Neri Niccolai, Samuel E. Butcher
Vincenzo Venditti
The surface accessibility of macromolecules plays a key role in modulating molecular recognition events. RNA is a complex and dynamic molecule involved in many aspects of gene expression. However, there are few experimental methods available to measure the accessible surface of RNA. Here, we investigate the accessible surface of RNA using NMR and the small paramagnetic molecule TEMPOL. We investigated two RNAs with known structures, one that is extremely stable and one that is dynamic. For helical regions, the TEMPOL probing data correlate well with the predicted RNA surface, and the method is able to distinguish subtle variations in atom …
Structure And Thermodynamics Of A Conserved U2 Snrna Domain From Yeast And Human, Dipali G. Sashital, Vincenzo Venditti, Courtney G. Angers, Gabriel Cornilescu, Samuel E. Butcher
Structure And Thermodynamics Of A Conserved U2 Snrna Domain From Yeast And Human, Dipali G. Sashital, Vincenzo Venditti, Courtney G. Angers, Gabriel Cornilescu, Samuel E. Butcher
Vincenzo Venditti
The spliceosome is a dynamic ribonucleoprotein complex responsible for the removal of intron sequences from pre-messenger RNA. The highly conserved 5′ end of the U2 small nuclear RNA (snRNA) makes key base-pairing interactions with the intron branch point sequence and U6 snRNA. U2 stem I, a stem–loop located in the 5′ region of U2, has been implicated in spliceosome assembly and may modulate the folding of the U2 and U6 snRNAs in the spliceosome active site. Here we present the NMR structures of U2 stem I from human and Saccharomyces cerevisiae. These sequences represent the two major classes of U2 …
Capsular Hyaluronic Acid-Mediated Adhesion Of Pasteurella Multocida To Turkey Air Sac Macrophages, Ingrid M. Pruimboom, Richard B. Rimler, Mark R. Ackermann, Kim A. Brogden
Capsular Hyaluronic Acid-Mediated Adhesion Of Pasteurella Multocida To Turkey Air Sac Macrophages, Ingrid M. Pruimboom, Richard B. Rimler, Mark R. Ackermann, Kim A. Brogden
Mark R. Ackermann
Serogroup A strains of Pasteurella multocida, the major cause of fowl cholera, are resistant to phagocytosis in nonimmunized birds. Adherence studies with a capsulated strain of P multocida (serotype A:3) and turkey air sac macrophages in culture showed that the bacteria were capable of adhering in large numbers to the macrophages but were not internalized. A noncapsulated variant of the bacteria (serotype -:3) showed little or no adherence and was not internalized. These data indicated that the adhesive properties were caused by the presence of a capsule on the bacteria. The role of capsular hyaluronic acid in adherence to macrophages …