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Articles 61 - 90 of 178

Full-Text Articles in Organisms

Conversion Of An Instantaneous Activating K+ Channel Into A Slow Activating Inward Rectifier, Dirk Baumeister, Brigitte Hertel, Indra Schroeder, Sabrina Gazzarrini, Stefan M. Kast, James L. Van Etten, Anna Moroni, Gerhard Thiel Jan 2017

Conversion Of An Instantaneous Activating K+ Channel Into A Slow Activating Inward Rectifier, Dirk Baumeister, Brigitte Hertel, Indra Schroeder, Sabrina Gazzarrini, Stefan M. Kast, James L. Van Etten, Anna Moroni, Gerhard Thiel

James Van Etten Publications

The miniature channel, Kcv, is a structural equivalent of the pore of all K+ channels. Here, we follow up on a previous observation that a largely voltage-insensitive channel can be converted into a slow activating inward rectifier after extending the outer transmembrane domain by one Ala. This gain of rectification can be rationalized by dynamic salt bridges at the cytosolic entrance to the channel; opening is favored by voltage-sensitive formation of salt bridges and counteracted by their disruption. Such latent voltage sensitivity in the pore could be relevant for the understanding of voltage gating in complex Kv channels.


Structure Of The N-Glycans From The Chlorovirus Ne-Jv-1, Immacolata Speciale, Irina Agarkova, Garry Duncan, James L. Van Etten, Cristina De Castro Jan 2017

Structure Of The N-Glycans From The Chlorovirus Ne-Jv-1, Immacolata Speciale, Irina Agarkova, Garry Duncan, James L. Van Etten, Cristina De Castro

James Van Etten Publications

Results from recent studies are breaking the paradigm that all viruses depend on their host machinery to glycosylate their proteins. Chloroviruses encode several genes involved in glycan biosynthesis and some of their capsid proteins are decorated with N-linked oligosaccharides with unique features. Here we describe the elucidation of the N-glycan structure of an unusual chlorovirus, NE-JV-1, that belongs to the Pbi group. The host for NE-JV-1 is the zoochlorella Micractinium conductrix. Spectroscopic analyses established that this N-glycan consists of a core region that is conserved in all of the chloroviruses. The one difference is that the residue 3OMe-l-rhamnose is …


Structural Studies Demonstrating A Bacteriophage-Like Replication Cycle Of The Eukaryote-Infecting Paramecium Bursaria Chlorella Virus-1, Elad Milrot, Eyal Shimoni, Katya Rechav, Tamar Unger, James L. Van Etten, Abraham Minsky Jan 2017

Structural Studies Demonstrating A Bacteriophage-Like Replication Cycle Of The Eukaryote-Infecting Paramecium Bursaria Chlorella Virus-1, Elad Milrot, Eyal Shimoni, Katya Rechav, Tamar Unger, James L. Van Etten, Abraham Minsky

James Van Etten Publications

A fundamental stage in viral infection is the internalization of viral genomes in host cells. Although extensively studied, the mechanisms and factors responsible for the genome internalization process remain poorly understood. Here we report our observations, derived from diverse imaging methods on genome internalization of the large dsDNA Paramecium bursaria chlorella virus-1 (PBCV-1). Our studies reveal that early infection stages of this eukaryotic- infecting virus occurs by a bacteriophage-like pathway, whereby PBCV-1 generates a hole in the host cell wall and ejects its dsDNA genome in a linear, base-pair-by-base-pair process, through a membrane tunnel generated by the fusion of the …


Climate Change And The Integrity Of Science, Peter H. Gleick, James L. Van Etten, Members Of The U.S. National Academy Of Sciences Nov 2016

Climate Change And The Integrity Of Science, Peter H. Gleick, James L. Van Etten, Members Of The U.S. National Academy Of Sciences

James Van Etten Publications

We are deeply disturbed by the recent escalation of political assaults on scientists in general and on climate scientists in particular. All citizens should understand some basic scientific facts. There is always some uncertainty associated with scientific conclusions; science never absolutely proves anything. When someone says that society should wait until scientists are absolutely certain before taking any action, it is the same as saying society should never take action. For a problem as potentially catastrophic as climate change, taking no action poses a dangerous risk for our planet.

Scientific conclusions derive from an understanding of basic laws supported by …


Predators Catalyze An Increase In Chloroviruses By Foraging On The Symbiotic Hosts Of Zoochlorellae, John Delong, Zeina Al-Ameeli, Garry A. Duncan, James L. Van Etten, David D. Dunigan Ph. D. Nov 2016

Predators Catalyze An Increase In Chloroviruses By Foraging On The Symbiotic Hosts Of Zoochlorellae, John Delong, Zeina Al-Ameeli, Garry A. Duncan, James L. Van Etten, David D. Dunigan Ph. D.

James Van Etten Publications

Virus population growth depends on contacts between viruses and their hosts. It is often unclear how sufficient contacts are made between viruses and their specific hosts to generate spikes in viral abundance. Here, we show that copepods, acting as predators, can bring aquatic viruses and their algal hosts into contact. Specifically, predation of the protist Paramecium bursaria by copepods resulted in a >100-fold increase in the number of chloroviruses in 1 d. Copepod predation can be seen as an ecological “catalyst” by increasing contacts between chloroviruses and their hosts, zoochlorellae (endosymbiotic algae that live within paramecia), thereby facilitating viral population …


A Preliminary Study On The Role Of Enhancer Of Flavonoid Production (Efp) In Flavonoid Biosynthesis, Jia Guo May 2016

A Preliminary Study On The Role Of Enhancer Of Flavonoid Production (Efp) In Flavonoid Biosynthesis, Jia Guo

Honors Scholar Theses

Flavonoids are involved in a variety of biological roles ranging from pathogen protection, pigment intensity, antioxidant effects, and even prevention from cancer or cardiovascular diseases. Because of the diverse and beneficial functions that flavonoids have, the flavonoid biosynthetic pathway has been well studied. Recently, a gene called the Enhancer of Flavonoid Production (EFP) was discovered when mutations in this gene caused the Japanese morning glory flowers to exhibit a pale-colored phenotype. Although EFP is known to increase flavonoid production, the direct mechanism to how EFP enhances enzymes in the flavonoid biosynthetic pathway has yet to be discovered. It …


Antifungal Activity Of Essential Oils On Aspergillus Parasiticus Isolated From Peanuts, Mina M. Yooussef, Quyen Pham, Premila Achar, Marikunte Yanjarappa Sreenivasa Apr 2016

Antifungal Activity Of Essential Oils On Aspergillus Parasiticus Isolated From Peanuts, Mina M. Yooussef, Quyen Pham, Premila Achar, Marikunte Yanjarappa Sreenivasa

Faculty Articles

Aspergillus parasiticus is one of the most common fungi which contaminates peanuts by destroying peanut shells before they are harvested and the fungus produces aflatoxins. The aim of this study was to evaluate the antifungal activities of seventeen essential oils on the growth of the aflatoxigenic form of A. parasiticus in contaminated peanuts from commercial outlets in Georgia. The agar dilution method was used to test the antifungal activity of essential oils against this form of A. parasiticus at various concentrations: 500; 1,000; 1,500; 2,000; 2,500 ppm. Among the seventeen essential oils tested, the antifungal effect of cinnamon, lemongrass, clove …


Three-Year Survey Of Abundance, Prevalence And Genetic Diversity Of Chlorovirus Populations In A Small Urban Lake, Cristian F. Quispe, Olivia Sonderman, Anya Seng, Brenna Rasmussen, Garrett Weber, Claire Mueller, David Dunigan, James L. Van Etten Apr 2016

Three-Year Survey Of Abundance, Prevalence And Genetic Diversity Of Chlorovirus Populations In A Small Urban Lake, Cristian F. Quispe, Olivia Sonderman, Anya Seng, Brenna Rasmussen, Garrett Weber, Claire Mueller, David Dunigan, James L. Van Etten

James Van Etten Publications

Inland water environments cover about 2.5 percent of our planet and harbor huge numbers of known and still unknown microorganisms. In this report, we examined water samples for the abundance, prevalence, and genetic diversity of a group of infectious viruses (chloroviruses) that infect symbiotic chlorella-like green algae. Samples were collected on a weekly basis for a period of 24 to 36 months from a recreational freshwater lake in Lincoln, Nebraska, and assayed for infectious viruses by plaque assay. The numbers of infectious virus particles were both host- and site-dependent. The consistent fluctuations in numbers of viruses suggest their impact as …


Cell-Free And Cell-Based Approaches To Explore The Roles Of Host Membranes And Lipids In The Formation Of Viral Replication Compartment Induced By Tombusviruses, Peter D. Nagy, Judit Pogany, Kai Xu Mar 2016

Cell-Free And Cell-Based Approaches To Explore The Roles Of Host Membranes And Lipids In The Formation Of Viral Replication Compartment Induced By Tombusviruses, Peter D. Nagy, Judit Pogany, Kai Xu

Plant Pathology Faculty Publications

Plant positive strand RNA viruses are intracellular infectious agents that take advantage of cellular lipids and membranes to support replication and protect viral RNA from degradation by host antiviral responses. In this review, we discuss how Tomato bushy stunt virus (TBSV) co-opts lipid transfer proteins and modulates lipid metabolism and transport to facilitate the assembly of the membrane-bound viral replicase complexes within intricate replication compartments. Identification and characterization of the proviral roles of specific lipids and proteins involved in lipid metabolism based on results from yeast (Saccharomyces cerevisiae) model host and cell-free approaches are discussed. The review also …


Sex-Specific Fungal Communities Of The Dioicous Moss Ceratodon Purpureus, Mehmet Ali Balkan Jan 2016

Sex-Specific Fungal Communities Of The Dioicous Moss Ceratodon Purpureus, Mehmet Ali Balkan

Dissertations and Theses

Mosses display a number of hallmark life history traits that influence their ecology at the population and community level. The long lived separation of sexes observed in the haploid gametophyte (dioicy) is one such feature of particular importance, as it is observed in the majority of bryophytes and creates intraspecific specialization of male and female individuals.

The prevalence of sexually dimorphic mosses raises the possibility of sex-specific interactions with fungi as observed in some vascular plants. Here I investigated how moss sex shapes fungal communities associated with gametophytic tissues of the ubiquitous moss, Ceratodon purpureus. Using greenhouse populations of …


Virus–Host Interactions: Insights From The Replication Cycle Of The Large Paramecium Bursaria Chlorella Virus, Elad Milrot, Yael Mutsafi, Yael Fridmann-Sirkis, Eyal Shimoni, Katya Rechav, James Gurnon, James L. Van Etten, Abraham Minsky Jan 2016

Virus–Host Interactions: Insights From The Replication Cycle Of The Large Paramecium Bursaria Chlorella Virus, Elad Milrot, Yael Mutsafi, Yael Fridmann-Sirkis, Eyal Shimoni, Katya Rechav, James Gurnon, James L. Van Etten, Abraham Minsky

James Van Etten Publications

The increasing interest in cytoplasmic factories generated by eukaryotic-infecting viruses stems from the realization that these highly ordered assemblies may contribute fundamental novel insights to the functional significance of order in cellular biology. Here, we report the formation process and structural features of the cytoplasmic factories of the large dsDNA virus Paramecium bursaria chlorella virus 1 (PBCV-1). By combining diverse imaging techniques, including scanning transmission electron microscopy tomography and focused ion beam technologies, we show that the architecture and mode of formation of PBCV-1 factories are significantly different from those generated by their evolutionary relatives Vaccinia and Mimivirus. Specifically, PBCV-1 …


Chloroviruses N-Linked Glycans Share A New Type Of Conserved Core Architecture Unprecedented In Any Form Of Life / [Published As] N-Linked Glycans Of Chloroviruses Sharing A Core Architecture Without Precedent, Cristina De Castro, Immacolata Speciale, Garry Duncan, David Dunigan, Irina Agarkova, Rosa Lanzetta, Luisa Sturiale, Angelo Palmigiano, Domenico Garozzo, Antonio Molinaro, Michela Tonetti, James L. Van Etten Jan 2016

Chloroviruses N-Linked Glycans Share A New Type Of Conserved Core Architecture Unprecedented In Any Form Of Life / [Published As] N-Linked Glycans Of Chloroviruses Sharing A Core Architecture Without Precedent, Cristina De Castro, Immacolata Speciale, Garry Duncan, David Dunigan, Irina Agarkova, Rosa Lanzetta, Luisa Sturiale, Angelo Palmigiano, Domenico Garozzo, Antonio Molinaro, Michela Tonetti, James L. Van Etten

James Van Etten Publications

N-glycosylation is a fundamental modification of proteins that exists in the three domains of life and in some viruses, including the chloroviruses, for which a new type of core N-glycan is described. This N-glycan core structure common to all chloroviruses is a pentasaccharide with a β-glucose linked to an asparagine residue that is not located in the typical sequon N-X-T/S. The glucose is linked to a terminal xylose unit and a hyperbranched fucose, in turn substituted with a terminal galactose and a second xylose residue. The third position of the fucose unit is always linked to a rhamnose, which is …


Engineering Of A Light-Gated Potassium Channel, Christian Cosentino, Laura Alberio, Sabrina Gazzarrini, Marco Aquila, Eduardo Romano, Solei Cermenati, Paolo Zuccolini, Jan Petersen, Monica Beltrame, James L. Van Etten, John M. Christie, Gerhard Thiel, Anna Moroni Apr 2015

Engineering Of A Light-Gated Potassium Channel, Christian Cosentino, Laura Alberio, Sabrina Gazzarrini, Marco Aquila, Eduardo Romano, Solei Cermenati, Paolo Zuccolini, Jan Petersen, Monica Beltrame, James L. Van Etten, John M. Christie, Gerhard Thiel, Anna Moroni

James Van Etten Publications

The present palette of opsin-based optogenetic tools lacks a light-gated potassium (K+) channel desirable for silencing of excitable cells. Here, we describe the construction of a blue-light–induced K+ channel 1 (BLINK1) engineered by fusing the plant LOV2-Ja photosensory module to the small viral K+ channel Kcv. BLINK1 exhibits biophysical features of Kcv, including K+ selectivity and high single-channel conductance, but reversibly photoactivates in blue light. Opening of BLINK1 channels hyperpolarizes the cell to the K+ equilibrium potential. Ectopic expression of BLINK1 reversibly inhibits the escape response in light-exposed zebrafish larvae. BLINK1 therefore provides a single-component optogenetic tool that can establish …


Reply To Kjartansdóttir Et Al.: Chlorovirus Atcv-1 Findings Not Explained By Contamination, Robert H. Yolken, Lorraine Jones-Brando, David Dunigan, Geetha Kannan, Faith Dickerson, Emily Severance, Sarven Sabunciyan, C. Conover Talbot Jr., Emese Prandovszky, James Gurnon, Irina Agarkova, Flora Leister, Kristin L. Gressitt, Ou Chen, Bryan Deuber, Fangrui Ma, Mikhail V. Pletnikov, James L. Van Etten Mar 2015

Reply To Kjartansdóttir Et Al.: Chlorovirus Atcv-1 Findings Not Explained By Contamination, Robert H. Yolken, Lorraine Jones-Brando, David Dunigan, Geetha Kannan, Faith Dickerson, Emily Severance, Sarven Sabunciyan, C. Conover Talbot Jr., Emese Prandovszky, James Gurnon, Irina Agarkova, Flora Leister, Kristin L. Gressitt, Ou Chen, Bryan Deuber, Fangrui Ma, Mikhail V. Pletnikov, James L. Van Etten

James Van Etten Publications

We agree with Kjartansdóttir et al. (1) that extreme caution must be used when interpreting high-throughput sequencing results in new hosts. The situation demands thorough investigation and validation beyond the identification of a few sequencing reads. However, we believe it is unlikely that random laboratory contamination explains the results reported in Yolken et al. (2) for the following reasons. ...

Therefore, the conclusions in our report are based not only on “a few sequence reads” (1), but on confirmatory assays, as well as a highly controlled animal model of oral exposure and subsequent measurement of immune response and behavior. We …


Large Dsdna Chloroviruses Encode Diverse Membrane Transport Proteins, Gerhard Thiel, Timo Greiner, David Dunigan, Anna Moroni Jan 2015

Large Dsdna Chloroviruses Encode Diverse Membrane Transport Proteins, Gerhard Thiel, Timo Greiner, David Dunigan, Anna Moroni

James Van Etten Publications

Many large DNA viruses that infect certain isolates of chlorella-like green algae (chloroviruses) are unusual because they often encode a diverse set of membrane transport proteins, including functional K+ channels and aquaglyceroporins as well as K+ transporters and calcium transporting ATPases. Some chloroviruses also encode putative ligand-gated-like channel proteins. No one protein is present in all of the chloroviruses that have been sequenced, but the K+ channel is the most common as only two chloroviruses have been isolated that lack this complete protein. This review describes the properties of these membrane-transporting proteins and suggests possible physiological functions and evolutionary histories …


Characterization Of A Novel Fungal-Specific Gene, Fug1, In Fusarium Verticillioides, John Byron Ridenour Dec 2014

Characterization Of A Novel Fungal-Specific Gene, Fug1, In Fusarium Verticillioides, John Byron Ridenour

Graduate Theses and Dissertations

Filamentous fungi are responsible for numerous plant and animal diseases. The filamentous ascomycete Fusarium verticillioides is a globally important pathogen of maize, capable of causing severe yield reductions and economic losses. Also of substantial concern is the contamination of infected kernels with fumonisins, toxic secondary metabolites linked to toxicoses in humans and livestock. The number of sequenced fungal genomes is rapidly increasing. However, functional characterization of fungal genes has not progressed at a comparable rate. In pathogenic fungi, uncharacterized genes represent a source for novel virulence factors or anti-fungal targets. Therefore, to fully understand the genetic mechanisms underlying fungal pathogenesis, …


Chlorovirus Atcv-1 Is Part Of The Human Oropharyngeal Virome And Is Associated With Changes In Cognitive Functions In Humans And Mice, Robert H. Yolken, Lorraine Jones-Brando, David D. Dunigan, Geetha Kannan, Faith Dickerson, Emily Severance, Sarven Sabunciyan, C. Conover Talbot Jr., Emese Prandovszky, James R. Gurnon, Irina V. Agarkova, Flora Leister, Kristin L. Gressitt, Ou Chen, Bryan Deuber, Fangrui Ma, Mikhail V. Pletnikov, James L. Van Etten Nov 2014

Chlorovirus Atcv-1 Is Part Of The Human Oropharyngeal Virome And Is Associated With Changes In Cognitive Functions In Humans And Mice, Robert H. Yolken, Lorraine Jones-Brando, David D. Dunigan, Geetha Kannan, Faith Dickerson, Emily Severance, Sarven Sabunciyan, C. Conover Talbot Jr., Emese Prandovszky, James R. Gurnon, Irina V. Agarkova, Flora Leister, Kristin L. Gressitt, Ou Chen, Bryan Deuber, Fangrui Ma, Mikhail V. Pletnikov, James L. Van Etten

James Van Etten Publications

Chloroviruses (family Phycodnaviridae) are large DNA viruses known to infect certain eukaryotic green algae and have not been previously shown to infect humans or to be part of the human virome. We unexpectedly found sequences homologous to the chlorovirus Acanthocystis turfacea chlorella virus 1 (ATCV-1) in a metagenomic analysis of DNA extracted from human oropharyngeal samples. These samples were obtained by throat swabs of adults without a psychiatric disorder or serious physical illness who were participating in a study that included measures of cognitive functioning. The presence of ATCV-1 DNA was confirmed by quantitative PCR with ATCV-1 DNA being …


Chlorovirus Skp1-Binding Ankyrin Repeat Protein Interplay And Mimicry Of Cellular Ubiquitin Ligase Machinery, Eric A. Noel, Ming Kang, Jiri Adamec, James L. Van Etten, George A. Oyler Sep 2014

Chlorovirus Skp1-Binding Ankyrin Repeat Protein Interplay And Mimicry Of Cellular Ubiquitin Ligase Machinery, Eric A. Noel, Ming Kang, Jiri Adamec, James L. Van Etten, George A. Oyler

James Van Etten Publications

The ubiquitin-proteasome system is targeted by many viruses that have evolved strategies to redirect host ubiquitination machinery. Members of the genus Chlorovirus are proposed to share an ancestral lineage with a broader group of related viruses, nucleo-cytoplasmic large DNA viruses (NCLDV). Chloroviruses encode an Skp1 homolog and ankyrin repeat (ANK) proteins. Several chlorovirus-encoded ANK repeats contain C-terminal domains characteristic of cellular F-boxes or related NCLDV chordopox PRANC (pox protein repeats of ankyrin at C-terminal) domains. These observations suggested that this unique combination of Skp1 and ANK repeat proteins might form complexes analogous to the cellular Skp1-Cul1-F-box (SCF) ubiquitin ligase complex. …


Chlorovirus Pbcv-1 Encodes An Active Copper-Zinc Superoxide Dismutase, Ming Kang, Garry A. Duncan, Charles Kuszynski, George Oyler, Jiayin Zheng, Donald F. Becker, James L. Van Etten Aug 2014

Chlorovirus Pbcv-1 Encodes An Active Copper-Zinc Superoxide Dismutase, Ming Kang, Garry A. Duncan, Charles Kuszynski, George Oyler, Jiayin Zheng, Donald F. Becker, James L. Van Etten

James Van Etten Publications

Superoxide dismutases (SODs) are metalloproteins that protect organisms from toxic reactive oxygen species by catalyzing the conversion of superoxide anion to hydrogen peroxide and molecular oxygen. Chlorovirus PBCV-1 encodes a 187-amino-acid protein that resembles a Cu-Zn SOD with all of the conserved amino acid residues for binding copper and zinc (named cvSOD). cvSOD has an internal Met that results in a 165-amino-acid protein (named tcvSOD). Both cvSOD and tcvSOD recombinant proteins inhibited nitroblue tetrazolium reduction of superoxide anion generated in a xanthine-xanthine oxidase system in solution. tcvSOD was chosen for further characterization because it was easier to produce. Recombinant tcvSOD …


Expression Of Chlorovirus Mt325 Aquaglyceroporin (Aqpv1) In Tobacco And Its Role In Mitigating Drought Stress, Saadia Bihmidine, Mingxia Cao, Ming Kang, Tala Awada, James L. Van Etten, David Dunigan, Thomas E. Clemente Jul 2014

Expression Of Chlorovirus Mt325 Aquaglyceroporin (Aqpv1) In Tobacco And Its Role In Mitigating Drought Stress, Saadia Bihmidine, Mingxia Cao, Ming Kang, Tala Awada, James L. Van Etten, David Dunigan, Thomas E. Clemente

James Van Etten Publications

Main conclusions A Chlorovirus aquaglyceroporin expressed in tobacco is localized to the plastid and plasma membranes. Transgenic events display improved response to water deficit. Necrosis in adult stage plants is observed.

Aquaglyceroporins are a subclass of the water channel aquaporin proteins (AQPs) that transport glycerol along with other small molecules transcellular in addition to water. In the studies communicated herein, we analyzed the expression of the aquaglyceroporin gene designated, aqpv1, from Chlorovirus MT325, in tobacco (Nicotiana tabacum), along with phenotypic changes induced by aqpv1 expression in planta. Interestingly, aqpv1 expression under control of either a constitutive or …


Effects Of Arbuscular Mycorrhizal Fungal Infection And Common Mycelial Network Formation On Invasive Plant Competition, Rachael Elizabeth Workman Mar 2014

Effects Of Arbuscular Mycorrhizal Fungal Infection And Common Mycelial Network Formation On Invasive Plant Competition, Rachael Elizabeth Workman

Dissertations and Theses

Understanding the biotic factors influencing invasive plant performance is essential for managing invaded land and preventing further exotic establishment and spread. I studied how competition between both conspecifics and native co-habitants and arbuscular mycorrhizal fungal (AMF) impacted the success of the invasive bunchgrass Brachypodium sylvaticumin early growth stages. I examined whether invasive plants performed and competed differently when grown in soil containing AMF from adjacent invaded and noninvaded ranges in order to determine the contribution of AMF to both monoculture stability and spread of the invasive to noninvaded territory. I also directly manipulated common mycelial network (CMN) formation by AMF …


Phages Of Non-Diary Lactococci: Isolation And Characterization Of Phi L47, A Phage Infecting The Grass Isolate Lactococcus Lactis Ssp Cremoris Dpc6860, Daniel Cavanagh, Caitríona M. Guinane, Horst Neve, Aidan Coffey, R. Paul Ross, Gerald F. Fitzgerald, Olivia Mcauliffe Jan 2014

Phages Of Non-Diary Lactococci: Isolation And Characterization Of Phi L47, A Phage Infecting The Grass Isolate Lactococcus Lactis Ssp Cremoris Dpc6860, Daniel Cavanagh, Caitríona M. Guinane, Horst Neve, Aidan Coffey, R. Paul Ross, Gerald F. Fitzgerald, Olivia Mcauliffe

Department of Biological Sciences Publications

Lactococci isolated from non-dairy sources have been found to possess enhanced metabolic activity when compared to dairy strains. These capabilities may be harnessed through the use of these strains as starter or adjunct cultures to produce more diverse flavor profiles in cheese and other dairy products. To understand the interactions between these organisms and the phages that infect them, a number of phages were isolated against lactococcal strains of non-dairy origin. One such phage, ΦL47, was isolated from a sewage sample using the grass isolate L. lactis ssp. cremoris DPC6860 as a host. Visualization of phage virions by transmission electron …


Viruses As Nanoparticles: Structure Versus Collective Dynamics, S. Sirotkin, A. Mermet, M. Bergoin, V. Ward, James L. Van Etten Jan 2014

Viruses As Nanoparticles: Structure Versus Collective Dynamics, S. Sirotkin, A. Mermet, M. Bergoin, V. Ward, James L. Van Etten

James Van Etten Publications

In order to test the application of the “nanoparticle” concept to viruses in terms of low-frequency dynamics, large viruses (140–190 nm) were compared to similar-sized polymer colloids using ultra-small-angle x-ray scattering and very-low-frequency Raman or Brillouin scattering. While both viruses and polymer colloids show comparable highly defined morphologies, with comparable abilities of forming self-assembled structures, their respective abilities to confine detectable acoustic vibrations, as expected for such monodisperse systems, differed. Possible reasons for these different behaviors are discussed.


Viruses Infecting Marine Picoplancton Encode Functional Potassium Ion Channels, Fenja Siotto, Corinna Martin, Oliver Rauh, James L. Van Etten, Indra Schroeder, Anna Moroni, Gerhard Thiel Jan 2014

Viruses Infecting Marine Picoplancton Encode Functional Potassium Ion Channels, Fenja Siotto, Corinna Martin, Oliver Rauh, James L. Van Etten, Indra Schroeder, Anna Moroni, Gerhard Thiel

James Van Etten Publications

Phycodnaviruses are dsDNA viruses, which infect algae. Their large genomes encode many gene products, like small K+ channels, with homologs in prokaryotes and eukaryotes. Screening for K+ channels revealed their abundance in viruses from fresh-water habitats. Recent sequencing of viruses from marine algae or from salt water in Antarctica revealed sequences with the predicted characteristics of K+ channels but with some unexpected features. Two genes encode either 78 or 79 amino acid proteins, which are the smallest known K+ channels. Also of interest is an unusual sequence in the canonical α-helixes in K+ channels. Structural prediction algorithms indicate that the …


A Literature Review Of The Health Effects Of A Plant Based Diet Versus An Animal Based Diet, James Cote May 2013

A Literature Review Of The Health Effects Of A Plant Based Diet Versus An Animal Based Diet, James Cote

Senior Honors Theses

Health and nutrition can mean a myriad of things to many people in today’s culture. The majority of the time people are unaware of the proper nutrients their body needs and how to get them from food. This thesis will seek to expose the health benefits that are associated with consuming a raw plant-based die, offering a more profound and encompassing view on nutrition. Investigating further into today’s most common diseases such as diabetes, heart disease, obesity, cancer and autoimmune disorders, it will seek to discover and answer why we have so many health issues. This thesis will discuss the …


The Voltage-Sensing Domain Of A Phosphatase Gates The Pore Of A Potassium Channel, Cristina Arrigoni, Indra Schroeder, Giulia Romani, James L. Van Etten, Gerhard Thiel, Anna Moroni Feb 2013

The Voltage-Sensing Domain Of A Phosphatase Gates The Pore Of A Potassium Channel, Cristina Arrigoni, Indra Schroeder, Giulia Romani, James L. Van Etten, Gerhard Thiel, Anna Moroni

James Van Etten Publications

The modular architecture of voltage-gated K+ (Kv) channels suggests that they resulted from the fusion of a voltage-sensing domain (VSD) to a pore module. Here, we show that the VSD of Ciona intestinalis phosphatase (Ci-VSP) fused to the viral channel Kcv creates KvSynth1, a functional voltage-gated, outwardly rectifying K+ channel. KvSynth1 displays the summed features of its individual components: pore properties of Kcv (selectivity and filter gating) and voltage dependence of Ci-VSP (V1/2 = +56 mV; z of approx. 1), including the depolarizationinduced mode shift. The degree of outward rectification of the channel is critically …


A Virus-Encoded Potassium Ion Channel Is A Structural Protein In The Chlorovirus Paramecium Bursaria Chlorella Virus 1 Virion, Giulia Romani, Adrianna Piotrowski, Stefan Hillmer, James Gurnon, James L. Van Etten, Anna Moroni, Gerhard Thiel, Brigitte Hertel Jan 2013

A Virus-Encoded Potassium Ion Channel Is A Structural Protein In The Chlorovirus Paramecium Bursaria Chlorella Virus 1 Virion, Giulia Romani, Adrianna Piotrowski, Stefan Hillmer, James Gurnon, James L. Van Etten, Anna Moroni, Gerhard Thiel, Brigitte Hertel

James Van Etten Publications

Most chloroviruses encode small K+ channels, which are functional in electrophysiological assays. The experimental finding that initial steps in viral infection exhibit the same sensitivity to channel inhibitors as the viral K+ channels has led to the hypothesis that the channels are structural proteins located in the internal membrane of the virus particles. This hypothesis was questioned recently because proteomic studies failed to detect the channel protein in virions of the prototype chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1). Here, we used a mAb raised against the functional K+ channel from chlorovirus MA-1D to search for the viral K+ channel …


A Virus-Encoded Potassium Ion Channel Is A Structural Protein In The Chlorovirus Paramecium Bursaria Chlorella Virus 1 Virion, Giulia Romani, Adrianna Piotrowski, Stefan Hillmer, James Gurnon, James L. Van Etten, Anna Morani, Gerhard Thiel, Brigitte Hertel Jan 2013

A Virus-Encoded Potassium Ion Channel Is A Structural Protein In The Chlorovirus Paramecium Bursaria Chlorella Virus 1 Virion, Giulia Romani, Adrianna Piotrowski, Stefan Hillmer, James Gurnon, James L. Van Etten, Anna Morani, Gerhard Thiel, Brigitte Hertel

James Van Etten Publications

Most chloroviruses encode small K+ channels, which are functional in electrophysiological assays. The experimental finding that initial steps in viral infection exhibit the same sensitivity to channel inhibitors as the viral K+ channels has led to the hypothesis that the channels are structural proteins located in the internal membrane of the virus particles. This hypothesis was questioned recently because proteomic studies failed to detect the channel protein in virions of the prototype chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1). Here, we used a mAb raised against the functional K+ channel from chlorovirus MA-1D to search for the viral K+ channel …


Potassium Ion Channels: Could They Have Evolved From Viruses?1[W], Gerhard Thiel, Anna Moroni, Guillaume Blanc, James L. Van Etten Jan 2013

Potassium Ion Channels: Could They Have Evolved From Viruses?1[W], Gerhard Thiel, Anna Moroni, Guillaume Blanc, James L. Van Etten

James Van Etten Publications

Cells communicate among themselves by electrical activity. Sophisticated membrane-embedded proteins, called ion channels, catalyze rapid, selective, and regulated ion fluxes across membranes (Hille, 2001). The resulting membrane currents are responsible for neuronal activity and the systemic propagation of electrical signals in animals. The activity of some channels is important for muscle movement in animals or growth in plants; other channels sense the concentration of physiological signals and modulate key processes in all kinds of eukaryotic cells. Among the many diverse ion channels in higher organisms, K+ channels are among the most important. One feature of K+ channels is that they …


Minimal Art: Or Why Small Viral K+ Channels Are Good Tools For Understanding Basic Structure And Function Relations, Gerhard Thiel, Dirk Baumeister, Indra Schroeder, Stefan M. Kast, James L. Van Etten, Anna Moroni Jan 2011

Minimal Art: Or Why Small Viral K+ Channels Are Good Tools For Understanding Basic Structure And Function Relations, Gerhard Thiel, Dirk Baumeister, Indra Schroeder, Stefan M. Kast, James L. Van Etten, Anna Moroni

James Van Etten Publications

Some algal viruses contain genes that encode proteins with the hallmarks of K+ channels. One feature of these proteins is that they are less than 100 amino acids in size, which make them truly minimal for a K+ channel protein. That is, they consist of only the pore module present in more complex K+ channels. The combination of miniature size and the functional robustness of the viral K+ channels make them ideal model systems for studying how K+ channels work. Here we summarize recent structure/function correlates from these channels, which provide insight into functional properties such as gating, pharmacology and …