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Provitamin A Biofortification Of Cassava Enhances Shelf Life But Reduces Dry Matter Content Of Storage Roots Due To Altered Carbon Partitioning Into Starch, Getu Beyene, Felix R. Solomon, Raj D. Chauhan, Eliana Gaitán-Solis, Narayanan Narayanan, Jackson Gehan, Dimuth Siritunga, Robin L. Stevens, John Jifon, Joyce Van Eck, Edward Linsler, Malia Gehan, Muhammad Ilyas, Martin Fregene, Richard T. Sayre, Paul Anderson, Nigel Taylor, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty and Staff Publications

Storage roots of cassava (Manihot esculenta Crantz), a major subsistence crop of sub-Saharan Africa, are calorie rich but deficient in essential micronutrients, including provitamin A β-carotene. In this study, β-carotene concentrations in cassava storage roots were enhanced by coexpression of transgenes for deoxy-d-xylulose-5-phosphate synthase (DXS) and bacterial phytoene synthase (crtB), mediated by the patatin-type 1 promoter. Storage roots harvested from field-grown plants accumulated carotenoids to ≤50 lg/g DW, 15- to 20-fold increases relative to roots from nontransgenic plants. Approximately 85%–90% of these carotenoids accumulated as all-trans-β-carotene, the most nutritionally efficacious carotenoid. β-Carotene-accumulating storage roots displayed delayed onset of postharvest …

Multiple Origins Of Endosymbionts In Chlorellaceae With No Reductive Effects On The Plastid Or Mitochondrial Genomes, Weishu Fan, Wenhu Guo, James L. Van Etten, Jeffrey P. Mower

James Van Etten Publications

Ancient endosymbiotic relationships have led to extreme genomic reduction in many bacterial and eukaryotic algal endosymbionts. Endosymbionts in more recent and/or facultative relationships can also experience genomic reduction to a lesser extent, but little is known about the effects of the endosymbiotic transition on the organellar genomes of eukaryotes. To understand how the endosymbiotic lifestyle has affected the organellar genomes of photosynthetic green algae, we generated the complete plastid genome (plastome) and mitochondrial genome (mitogenome) sequences from three green algal endosymbionts (Chlorella heliozoae, Chlorella variabilis and Micractinium conductrix). The mitogenomes and plastomes of the three newly sequenced endosymbionts …

Differentially Regulated Orthologs In Sorghum And The Subgenomes Of Maize, Yang Zhang, Daniel W. Ngu, Daniel Santana De Carvalho, Zhikai Liang, Yumou Qiu, Rebecca Roston, James C. Schnable

Center for Plant Science Innovation: Faculty and Staff Publications

Identifying interspecies changes in gene regulation, one of the two primary sources of phenotypic variation, is challenging on a genome-wide scale. The use of paired time-course data on cold-responsive gene expression in maize (Zea mays) and sorghum (Sorghum bicolor) allowed us to identify differentially regulated orthologs. While the majority of cold-responsive transcriptional regulation of conserved gene pairs is species specific, the initial transcriptional responses to cold appear to be more conserved than later responses. In maize, the promoters of genes with conserved transcriptional responses to cold tend to contain more micrococcal nuclease hypersensitive sites in their …

Induction And Suppression Of Antiviral Rna Silencing By Tomato Spotted Wilt Virus, Sergio M. Gabriel Peralta

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Tomato spotted wilt virus (TSWV) is an emerging pathogen with wide host range and one of the most important viruses of plants. Information regarding processing of negative single stranded RNA viruses such as TSWV in the RNA silencing pathway remains limited. In nature TSWV is only transmitted by thrips as vectors and since infection occurs in both thrips and plants, an experimental system to transmit using thrips and the detection of TSWV were established. In order to understand the processing of TSWV in the RNA silencing pathway, Arabidopsis thaliana as a model plant was used in the genetic analysis against …

Cover Crops: A Primer, Joshua J. Miller, Katja Koehler-Cole, Rodrigo Werle, Daren Redfearn

Department of Plant Pathology: Faculty Publications

When deciding how best to use cover crops, it is important to consider the ultimate goal. Is it to increase soil organic matter, increase nutrient availability to subsequent crops, reduce soil compaction, supply forage for livestock, and/or suppress weeds? Answering these questions will help identify the cover crops that offer the best chance of success for meeting the goal. Primarily, cover crops are used to enhance soil conservation, nutrient cycling and supply, and weed control. However, these benefits vary based on the species of cover crop that is planted, so it is important to select the crop type that will …

First Report Of Xanthomonas Vasicola Causing Bacterial Leaf Streak On Corn In The United States, K. A. Korus, J. M. Lang, A. O. Adesemoye, C. C. Block, N. Pal, J. E. Leach, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

In 2014 and 2015, Zea mays samples (field, seed, and popcorn) were submitted to the Plant and Pest Diagnostic Clinic at the University of Nebraska–Lincoln displaying long, dark, yellow to brown, water-soaked, linear lesions confined to the interveinal spaces of the leaves. Initial symptoms appeared as small water-soaked flecks that expanded between veins to form irregular lesions. In some cases, the disease progressed to cover 40 to 50% of the leaf area. The disease was confirmed by symptom expression and bacterial streaming in 41 counties in Nebraska as well as Yuma Co., Colorado, and Phillips Co., Kansas, both contiguous to …

Identification Of Intrahelical Bifurcated H‑Bonds As A New Type Of Gate In K+ Channels, Oliver Rauh, Martin Urban, Leonhard M. Henkes, Tobias Winterstein, Timo Greiner, James L. Van Etten, Anna Moroni, Stefan M. Kast, Gerhard Thiel, Indra Schroeder

James Van Etten Publications

Gating of ion channels is based on structural transitions between open and closed states. To uncover the chemical basis of individual gates, we performed a comparative experimental and computational analysis between two K⁺ channels, Kcv_S and Kcv_NTS. These small viral encoded K+ channel proteins, with a monomer size of only 82 amino acids, resemble the pore module of all complex K+ channels in terms of structure and function. Even though both proteins share about 90% amino acid sequence identity, they exhibit different open probabilities with ca. 90% in Kcv_NTS and 40% in Kcv_S. …

A Specialized Diacylglycerol Acyltransferase Contributes To The Extreme Medium-Chain Fatty Acid Content Of Cuphea Seed Oil, Umidjon Iskandarov, Jillian E. Silva, Hae Jin Kim, Mariette Andersson, Rebecca E. Cahoon, Keithanne Mockaitis, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty and Staff Publications

Seed oils of many Cuphea sp. contain .90% of medium-chain fatty acids, such as decanoic acid (10:0). These seed oils, which are among the most compositionally variant in the plant kingdom, arise from specialized fatty acid biosynthetic enzymes and specialized acyltransferases. These include lysophosphatidic acid acyltransferases (LPAT) and diacylglycerol acyltransferases (DGAT) that are required for successive acylation of medium-chain fatty acids in the sn-2 and sn-3 positions of seed triacylglycerols (TAGs). Here we report the identification of a cDNA for a DGAT1-type enzyme, designated CpuDGAT1, from the transcriptome of C. avigera var pulcherrima developing seeds. Microsomes of camelina (Camelina …

Detecting, Cloning, And Screening For Suppressors Of Rna Silencing In Maize Chlorotic Mottle Virus And Sugarcane Mosaic Virus, Nicole E. Bacheller

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Maize lethal necrosis disease (MLND) is one of the most important viral diseases of maize. MLND occurs when Maize chlorotic mottle virus (MCMV) co-infects the same plant with one of several potyviruses, including Sugarcane mosaic virus, Wheat streak mosaic virus or Maize dwarf mosaic virus. Originally prevalent in the Midwest and Peru in the 1970s, the disease was called corn lethal necrosis (CLN) and was controlled through breeding and sanitation. Recently, the disease has re-emerged in East Africa and is rapidly spreading and threatening the food sources of subsistence-farming populations. This re-emergence has raised several questions about the unknown …

The Lx Report Of The Bean Improvement Cooperative No. 60, March 2017.

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

CONTENTS

LX Annual Report of the Bean Improvement Cooperative xi

BIC Coordinating Committee Membership - 1957 to 2017 . xii

BIC Meritorious Service and Distinguished Achievement Award Recipients - 1957 to 2015 xiii

BIC Awards Nomination Request for 2017 xvi

BIC/NAPIA Meeting in 2017 . xix

In Memory of Guillermo E. Galvez-Enriquez xx

RESEARCH PAPERS FOR 2017

OPTIMIZING SPORULATION OF Pseudocercospora griseola IN VITRO • Paula F. de Pádua1, Rafael Pereira1, Luanna B. W. Gomes1 and Elaine A. de Souza1* 1

FINE MAPPING THE BROAD SPECTRUM ANTHRACNOSE RESISTANCE GENE IN AMENDOIM CAVALO 3 • Gilio, T.A.S.1, Oscar P. Hurtado-Gonzales2, Giseli …

Proceedings Of The 44th Annual Meeting, Southern Soybean Disease Workers (March 8-9, 2017, Pensacola Beach, Florida), Terry Spurlock, Trey Price, Heather M. Kelly, Danise Beadle, Patricia Bollich, Tom Allen

Southern Soybean Disease Workers: Conference Proceedings

Contents

Agenda for March 8-9, 2017

Contributed papers

Soybean cyst nematode: current status, challenges and opportunities. G Tylka and K Bissonnette

Updates of the 2nd SCN (Soybean Cyst Nematode) Coalition. Albert Tenuta

Developing management zones for nematodes in soybean. C Overstreet, EC McGawley, DM Xavier-Mis, and M Kularathna

Microbial communities associated with long-term tillage and fertilizer management practices. AY Srour, J Hackman, RL Cook, JP Bond, and AM Fakhoury

Microbial profile of SDS-suppressive soils in soybean fields. AY Srour, LFS Leonardo, DK Malvick, JP Bond, and AM Fakhoury

Understanding the phytobiome; using strip trials and spatial analysis to determine concomitant …

Towards The Development Of A Sustainable Soya Bean-Based Feedstock For Aquaculture, Hyunwoo Park, Steven Weier, Fareha Razvi, Pamela A. Peña, Neil A. Sims, Jennica Lowell, Cory Hungate, Karma Kissinger, Gavin Key, Paul Fraser, Jonathan Napier, Edgar B. Cahoon, Thomas Clemente

Center for Plant Science Innovation: Faculty and Staff Publications

Soya bean (Glycine max (L.) Merr.) is sought after for both its oil and protein components. Genetic approaches to add value to either component are ongoing efforts in soya bean breeding and molecular biology programmes. The former is the primary vegetable oil consumed in the world. Hence, its primary usage is in direct human consumption. As a means to increase its utility in feed applications, thereby expanding the market of soya bean coproducts, we investigated the simultaneous displacement of marine ingredients in aquafeeds with soya bean-based protein and a high Omega-3 fatty acid soya bean oil, enriched with alpha-linolenic …

Novel Gene-Sequence Markers For Isolate Tracking Within Monilinia Fructicola Lesions, Madeline E. Dowling, Guido Schnabel, Harriet G. Boatwright, Sydney E. Everhart

Department of Plant Pathology: Faculty Publications

Background: Monilinia fructicola is a diverse pathogen of pome and stone fruits that causes severe economic losses each year. However, little is known about inoculum flow within or between orchards and pathogen establishment in an orchard, because few methods exist for detecting diversity or tracking isolates over time. SSR loci are an effective option, but may be confounded by a high degree of mutability and potential sensitivity to abiotic stress.

Results: Through transcriptome analysis, we identified novel markers mrr1, DHFR and MfCYP01 and validated stability of these markers under fungicide stress in natural infection sites. Nucleotide variation …

The Magnaporthe Oryzae Nitrooxidative Stress Response Suppresses Rice Innate Immunity During Blast Disease, Margarita Marroquin-Guzman, David E. Hartline, Janet D. Wright, Christian G. Elowsky, Travis J. Bourret, Richard A. Wilson

Department of Plant Pathology: Faculty Publications

Understanding how microorganisms manipulate plant innate immunity and colonize host cells is a major goal of plant pathology. Here, we report that the fungal nitrooxidative stress response suppresses host defenses to facilitate the growth and development of the important rice pathogen Magnaporthe oryzae in leaf cells. Nitronate monooxygenases encoded by NMO genes catalyze the oxidative denitrification of nitroalkanes. We show that the M. oryzae NMO2 gene is required for mitigating damaging lipid nitration under nitrooxidative stress conditions and, consequently, for using nitrate and nitrite as nitrogen sources. On plants, the Δnmo2 mutant strain penetrated host cuticles like wild type, …

The Morphogenesis-Related Ndr Kinase Pathway Of Colletotrichum Orbiculare Is Required For Translating Plant Surface Signals Into Infection-Related Morphogenesis And Pathogenesis, Sayo Kodama, Junya Ishizuka, Ito Miyashita, Takaaki Ishii, Takumi Nishiuchi, Hideto Miyoshi, Yasuyuki Kubo

Department of Plant Pathology: Faculty Publications

Plant infection by pathogenic fungi involves the differentiation of appressoria, specialized infection structures, initiated by fungal sensing and responding to plant surface signals. How plant fungal pathogens control infection-related morphogenesis in response to plant-derived signals has been unclear. Here we showed that the morphogenesis-related NDR kinase pathway (MOR) of the cucumber anthracnose fungus Colletotrichum orbiculare is crucial for appressorium development following perception of plant-derived signals. By screening of random insertional mutants, we identified that the MOR element CoPag1 (Perish-in-theabsence-of-GYP1) is a key component of the plant-derived signaling pathway involved in appressorium morphogenesis. Constitutive activation of the NDR kinase …

Phenotypic And Genotypic Characterization Of Relevant Sclerotinia Sclerotiorum Isolates, Thomas J. Justo Miorini, Anthony G. Pannullo, T. Hornby, Robert Higgins, Sydney E. Everhart, James R. Steadman

Department of Plant Pathology: Faculty Publications

Knowledge of pathogen population structure is useful to identify isolates for screening cultivars and lines for resistance. For S. sclerotiorum, causal agent of white mold in more than 400 plant species, including common bean and soybean, breeding for resistance is particularly challenging. The objective of this study was to characterize phenotypic and genotypic variation of S. sclerotiorum isolates from soybean production areas of the U.S.A. (15), Brazil (75), and Argentina (5) to compare them with 366 isolates from dry bean characterized previously (Everhart et al., 2016).

Muti Site Screening Identifies And Verifies Levels Of Resistance To White Mold In Common Bean In 2016, Robert Higgins, James R. Steadman

Department of Plant Pathology: Faculty Publications

The development of common bean cultivars with partial resistance and/ or avoidance to white mold (WM) caused by Sclerotinia sclerotiorum would benefit producers by reducing yield loss and reducing input costs for fungicides. Our main objective in this study is to identify bean germplasm supplied by bean breeders from across the USA and Belgium with levels of partial resistance to WM. Breeders sent seed of 9 bean lines for field testing and 25 bean lines for greenhouse testing with putative sources of resistance to our laboratory. The seeds were divided in equal amounts for field (400g/line) and/or greenhouse (25 seeds/ …

Lsp Family Proteins Regulate Antibiotic Biosynthesis In Lysobacter Enzymogenes Oh11, Ruping Wang, Huiyong Xu, Yangyang Zhao, Juan Zhang, Gary Y. Yuen, Guoliang Qian, Fengquan Liu

Department of Plant Pathology: Faculty Publications

Ax21 family proteins have been shown to play regulatory roles in plant- and animal-pathogenic species in the bacterial family Xanthomonadaceae, but the protein have not been investigated previously in the non-pathogenic members of this bacterial family. Lysobacter enzymogenes, is a non-pathogenic species known for its capacity as a biocontrol agent of plant pathogens. It is also noted for the production of antimicrobial secondary metabolites, heat stable antifungal factor (HSAF) and WAP-8294A2, that have potential for agricultural and pharmaceutical applications. The species also displays type IV pili-dependent twitching motility and the production of multiple extracellular lytic enzymes as additional biocontrol-related traits. …

Species Delimitation And Description Of Mesocriconema Nebraskense N. Sp. (Nematoda: Criconematidae), A Morphologically Cryptic, Parthenogenetic Species From North American Grasslands, Magdalena Olson, Timothy Harris, Rebecca Higgins, Peter Mullin, Kirsten Powers, Sean Olson, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

Nematode surveys of North American grasslands conducted from 2010 to 2015 frequently recovered a species of criconematid nematode morphologically resembling Mesocriconema curvatum. These specimens were recovered from remnant native prairies in the central tallgrass ecoregion of North America, and not from surrounding agroecosystems. Historical records indicate that M. curvatum is a cosmopolitan species feeding on a wide range of agronomic and native plants. DNA barcoding indicates North American grasslands contain at least 10 phylogenetically distinct lineages of Mesocriconema that resemble, but are not, M. curvatum. Analysis of the two most common lineages reveals two distinctly different population structures. …

Wheat Streak Mosaic Virus Coat Protein Deletion Mutants Elicit More Severe Symptoms Than Wild-Type Virus In Multiple Cereal Hosts, Satyanarayana Tatineni, Christian G. Elowsky, Robert A. Graybosch

Department of Plant Pathology: Faculty Publications

Previously, we reported that coat protein (CP) of Wheat streak mosaic virus (WSMV) (genus Tritimovirus, family Potyviridae) tolerates deletion of amino acids 36 to 84 for efficient systemic infection of wheat. In this study, we demonstrated that WSMV mutants with deletion of CP amino acids 58 to 84 but not of 36 to 57 induced severe chlorotic streaks and spots, followed by acute chlorosis in wheat, maize, barley, and rye compared with mild to moderate chlorotic streaks and mosaic symptoms by wild-type virus. Deletion of CP amino acids 58 to 84 from the WSMV genome accelerated cell-to-cell movement, …

Detection And Characterization Of Xanthomonas Vasicola Pv. Vasculorum (Cobb 1894) Comb. Nov. Causing Bacterial Leaf Streak Of Corn In The United States, J. M. Lang, E. Ducharme, J. Ibarra Caballero, E. Luna, T. Hartman, M. Ortiz-Castro, K. A. Korus, J. Rascoe, T. A. Jackson-Ziems, K. Broders, J. E. Leach

Department of Plant Pathology: Faculty Publications

Bacterial leaf streak of corn (Zea mays) recently reached epidemic levels in three corn-growing states and has been detected in another six states in the central United States. Xanthomonas vasicola was identified as the causal agent of this disease. A multilocus sequence alignment of six housekeeping genes and comparison of average nucleotide identity from draft genome sequence were used to confirm phylogenetic relationships and classification of this bacteria relative to other X. vasicola strains. X. vasicola isolates from Nebraska and South Africa were highly virulent on corn and sugarcane and less virulent on sorghum but caused water-soaking symptoms …

Plant Disease Management, Tamra A. Jackson-Ziems, Anthony O. Adesemoye, Loren J. Giesler, Robert M. Harveson, Stephen N. Wegulo, Joshua J. Miller, James D. Harbour

Department of Plant Pathology: Faculty Publications

Fungicides are an important component of the pesticide program for some Nebraska fields. While not all fields of corn, dry bean, sorghum, soybean, sugarbeet, sunflower, and wheat will require a fungicide application, it’s critical that you know the correct product for the disease in your field when you do need it.

Identification. The first step with any disease management program is to make sure you have correctly identified the problem. Identification is critical as there are many bacterial diseases with symptoms similar to fungal diseases, and fungicides will have no activity on them. For help identifying crop diseases, visit the …

Understanding Fungicide Resistance, Tamra A. Jackson-Ziems, Loren J. Giesler, Anthony O. Adesemoye, Robert M. Harveson, Stephen N. Wegulo

Department of Plant Pathology: Faculty Publications

Fungicide resistance has developed in some diseases of row crops as well as specialty crops. This implies that fungicide applications to control such diseases may no longer be effective. Scientific studies have shown that fungicide resistance develops through natural selection of a mutant strain of a pathogen in a population that is resistant to fungicides. Resistance is very difficult to eliminate but can be delayed through appropriate management practices. The availability of inexpensive options with single mode of action products being available makes this an important issue so we do not repeat what was done in weed management.

Introduction

Frogeye …

Corn Disease Update, Tamra A. Jackson-Ziems, Terra Hartman

Department of Plant Pathology: Faculty Publications

Several diseases were important in the 2016 Nebraska corn crop and impacted yield in some areas. Many of these diseases developed as a result of extreme weather events that were favorable for disease development. Most of those diseases are caused by pathogens that are capable of survival in the crop debris or residue, and so they are more likely to develop again in future years if environmental conditions are favorable again. This article summarizes some of Nebraska’s most important corn disease problems in 2016, tips for diagnosis, and management strategies.

Bacterial Leaf Streak

Gray Leaf Spot

Southern Rust

Stalk Rot …

Expression Of Cyanobacterial Fbp/Sbpase In Soybean Prevents Yield Depression Under Future Climate Conditions, Iris H. Köhler, Ursula M. Ruiz-Vera, Andy Vanloocke, Michell L. Thomey, Thomas Clemente, Stephen P. Long, Donald R. Ort, Carl J. Bernacchi

Center for Plant Science Innovation: Faculty and Staff Publications

Predictions suggest that current crop production needs to double by 2050 to meet global food and energy demands. Based on theory and experimental studies, overexpression of the photosynthetic enzyme sedoheptulose-1,7-bisphosphatase (SBPase) is expected to enhance C₃ crop photosynthesis and yields. Here we test how expression of the cyanobacterial, bifunctional fructose-1,6/sedoheptulose-1,7-bisphosphatase (FBP/SBPase) affects carbon assimilation and seed yield (SY) in a major crop (soybean, Glycine max). For three growing seasons, wild-type (WT) and FBP/SBPase-expressing (FS) plants were grown in the field under ambient (400 μmol mol⁻¹) and elevated (600 μmol mol⁻¹) CO₂ concentrations [CO …

Complete Mitochondrial Genomes From The Ferns Ophioglossum Californicum And Psilotum Nudum Are Highly Repetitive With The Largest Organellar Introns, Wenhu Guo, Andan Zhu, Weishu Fan, Jeffrey P. Mower

Center for Plant Science Innovation: Faculty and Staff Publications

• Currently, complete mitochondrial genomes (mitogenomes) are available from all major land plant lineages except ferns. Sequencing of fern mitogenomes could shed light on the major evolutionary transitions that established mitogenomic diversity among extant lineages.

• In this study, we generated complete mitogenomes from the adder’s tongue fern (Ophioglossum californicum) and the whisk fern (Psilotum nudum).

• The Psilotum mitogenome (628 kb) contains a rich complement of genes and introns, some of which are the largest of any green plant organellar genome. In the Ophioglossum mitogenome (372 kb), gene and intron content is slightly reduced, including the loss of …

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Structure Of The Chlorovirus Pbcv-1 Major Capsid Glycoprotein Determined By Combining Crystallographic And Carbohydrate Molecular Modeling Approaches, Cristina De Castro, Thomas Klose, Immacolata Speciale, Rosa Lanzetta, Antonio Molinaro, James L. Van Etten, Michael G. Rossmann

James Van Etten Publications

The glycans of the major capsid protein (Vp54) of Paramecium bursaria chlorella virus (PBCV-1) were recently described and found to be unusual. This prompted a reexamination of the previously reported Vp54 X-ray structure. A detailed description of the complete glycoprotein was achieved by combining crystallographic data with molecular modeling. The crystallographic data identified most of the monosaccharides located close to the protein backbone, but failed to detect those further from the glycosylation sites. Molecular modeling complemented this model by adding the missing monosaccharides and examined the conformational preference of the whole molecule, alone or within the crystallographic environment. Thus, combining …

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 …

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

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 …