College of Agriculture and Life Sciences (CALS)

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An aeroponic culture system for the study of root herbivory on Arabidopsis thaliana
Vaughan, Martha M.; Tholl, Dorothea; Tokuhisa, James G. (Biomed Central, 2011-03-10)
Background Plant defense against herbivory has been studied primarily in aerial tissues. However, complex defense mechanisms have evolved in all parts of the plant to combat herbivore attack and these mechanisms are likely to differ in the aerial and subterranean environment. Research investigating defense responses belowground has been hindered by experimental difficulties associated with the accessibility and quality of root tissue and the lack of bioassays using model plants with altered defense profiles. Results We have developed an aeroponic culture system based on a calcined clay substrate that allows insect herbivores to feed on plant roots while providing easy recovery of the root tissue. The culture method was validated by a root-herbivore system developed for Arabidopsis thaliana and the herbivore Bradysia spp. (fungus gnat). Arabidopsis root mass obtained from aeroponically grown plants was comparable to that from other culture systems, and the plants were morphologically normal. Bradysia larvae caused considerable root damage resulting in reduced root biomass and water absorption. After feeding on the aeroponically grown root tissue, the larvae pupated and emerged as adults. Root damage of mature plants cultivated in aeroponic substrate was compared to that of Arabidopsis seedlings grown in potting mix. Seedlings were notably more susceptible to Bradysia feeding than mature plants and showed decreased overall growth and survival rates. Conclusions A root-herbivore system consisting of Arabidopsis thaliana and larvae of the opportunistic herbivore Bradysia spp. has been established that mimics herbivory in the rhizosphere. Bradysia infestation of Arabidopsis grown in this culture system significantly affects plant performance. The culture method will allow simple profiling and in vivo functional analysis of root defenses such as chemical defense metabolites that are released in response to belowground insect attack.
Analysis of T-DNA alleles of flavonoid biosynthesis genes in Arabidopsis ecotype Columbia
Bowerman, Peter A.; Ramirez, Melissa V.; Price, Michelle B.; Helm, Richard F.; Winkel, Brenda S. J. (2012-09-04)
BACKGROUND: The flavonoid pathway is a long-standing and important tool for plant genetics, biochemistry, and molecular biology. Numerous flavonoid mutants have been identified in Arabidopsis over the past several decades in a variety of ecotypes. Here we present an analysis of Arabidopsis lines of ecotype Columbia carrying T-DNA insertions in genes encoding enzymes of the central flavonoid pathway. We also provide a comprehensive summary of various mutant alleles for these structural genes that have been described in the literature to date in a wide variety of ecotypes. FINDINGS: The confirmed knockout lines present easily-scorable phenotypes due to altered pigmentation of the seed coat (or testa). Knockouts for seven alleles for six flavonoid biosynthetic genes were confirmed by PCR and characterized by UPLC for altered flavonol content. CONCLUSION: Seven mutant lines for six genes of the central flavonoid pathway were characterized in ecotype, Columbia. These lines represent a useful resource for integrating biochemical and physiological studies with genomic, transcriptomic, and proteomic data, much of which has been, and continues to be, generated in the Columbia background.
Assessing age, breeding stage, and mating activity as drivers of variation in the reproductive microbiome of female tree swallows
Hernandez, Jessica; Hucul, Catherine; Reasor, Emily; Smith, Taryn; McGlothlin, Joel W.; Haak, David C.; Belden, Lisa K.; Moore, Ignacio T. (Wiley, 2021-07)
Sexually transmitted microbes are hypothesized to influence the evolution of reproductive strategies. Though frequently discussed in this context, our understanding of the reproductive microbiome is quite nascent. Indeed, testing this hypothesis first re-quires establishing a baseline understanding of the temporal dynamics of the reproductive microbiome and of how individual variation in reproductive behavior and age influence the assembly and maintenance of the reproductive microbiome as a whole. Here, we ask how mating activity, breeding stage, and age influence the reproductive microbiome. We use observational and experimental approaches to explain variation in the cloacal microbiome of free- living, female tree swallows (Tachycineta bicolor). Using microsatellite- based parentage analyses, we determined the number of sires per brood (a proxy for female mating activity). We experimentally increased female sexual activity by administering exogenous 17ß-estradiol. Lastly, we used bacterial 16S rRNA amplicon sequencing to characterize the cloacal microbiome. Neither the number of sires per brood nor the increased sexual activity of females significantly influenced female cloacal microbiome richness or community structure. Female age, however, was positively correlated with cloacal microbiome richness and influenced overall community structure. A hypothesis to explain these patterns is that the effect of sexual activity and the number of mates on variation in the cloacal microbiome manifests over an individual's lifetime. Additionally, we found that cloacal microbiome alpha diversity (Shannon Index, Faith's phylogenetic distance) decreased and community structure shifted between breeding stages. This is one of few studies to document within-individual changes and age- related differences in the cloacal microbiome across successive breeding stages. More broadly, our results contribute to our understanding of the role that host life history and behavior play in shaping the cloacal microbiomes of wild birds.
Attracting and Retaining Minorities in the Biomedical Sciences Including Genomics: a Community-based Approach
Smith, Edward J. (2014-08-21)
Candidate Gene Sequence Analyses toward Identifying Rsv3-Type Resistance to Soybean Mosaic Virus
Redekar, Neelam R.; Clevinger, Elizabeth M.; Laskar, M. A.; Biyashev, Ruslan M.; Ashfield, Tom; Jensen, Roderick V.; Jeong, Soon-Chun; Tolin, Sue A.; Saghai-Maroof, Mohammad A. (Crop Science Society of America, 2016-05-13)
Rsv3 is one of three genetic loci conferring strain-specific resistance to Soybean mosaic virus (SMV). The Rsv3 locus has been mapped to a 154-kb region on chromosome 14, containing a cluster of five nucleotide-binding leucine-rich repeat (NB-LRR) resistance genes. High sequence similarity between the Rsv3 candidate genes challenges fine mapping of the locus. Among the five, Glyma14g38533 showed the highest transcript abundance in 1 to 3 h of SMV-G7 inoculation. Comparative sequence analyses were conducted with the five Rsv3 candidate NB-LRR genes from susceptible (rsv-type) soybean [Glycine max (L.) Merr.] cultivar Williams 82, resistant (Rsv3-type) cultivar Hwangkeum, and resistant lines L29 and RRR. Sequence comparisons revealed that Glyma14g38533 had far more polymorphisms than the other candidate genes. Interestingly, Glyma14g38533 gene from Rsv3-type lines exhibited 150 single-nucleotide polymorphism (SNP and six insertion–deletion (InDel) markers relative to rsv-type line, Furthermore, the polymorphisms identified in three Rsv3-type lines were highly conserved. Several polymorphisms were validated in 18 Rsv3-type resistant and six rsv-type susceptible lines and were found associated with their disease response. The majority of the polymorphisms were located in LRR domain encoding region, which is involved in pathogen recognition via protein–protein interactions. These findings associating Glyma14g38533 with Rsv3-type resistance to SMV suggest it is the most likely candidate gene for Rsv3.
Changes in Gene Expression and Cellular Architecture in an Ovarian Cancer Progression Model
Creekmore, Amy L.; Silkworth, William T.; Cimini, Daniela; Jensen, Roderick V.; Roberts, Paul C.; Schmelz, Eva M. (PLOS, 2011-03-03)
Background Ovarian cancer is the fifth leading cause of cancer deaths among women. Early stage disease often remains undetected due the lack of symptoms and reliable biomarkers. The identification of early genetic changes could provide insights into novel signaling pathways that may be exploited for early detection and treatment. Methodology/Principal Findings Mouse ovarian surface epithelial (MOSE) cells were used to identify stage-dependent changes in gene expression levels and signal transduction pathways by mouse whole genome microarray analyses and gene ontology. These cells have undergone spontaneous transformation in cell culture and transitioned from non-tumorigenic to intermediate and aggressive, malignant phenotypes. Significantly changed genes were overrepresented in a number of pathways, most notably the cytoskeleton functional category. Concurrent with gene expression changes, the cytoskeletal architecture became progressively disorganized, resulting in aberrant expression or subcellular distribution of key cytoskeletal regulatory proteins (focal adhesion kinase, α-actinin, and vinculin). The cytoskeletal disorganization was accompanied by altered patterns of serine and tyrosine phosphorylation as well as changed expression and subcellular localization of integral signaling intermediates APC and PKCβII. Conclusions/Significance Our studies have identified genes that are aberrantly expressed during MOSE cell neoplastic progression. We show that early stage dysregulation of actin microfilaments is followed by progressive disorganization of microtubules and intermediate filaments at later stages. These stage-specific, step-wise changes provide further insights into the time and spatial sequence of events that lead to the fully transformed state since these changes are also observed in aggressive human ovarian cancer cell lines independent of their histological type. Moreover, our studies support a link between aberrant cytoskeleton organization and regulation of important downstream signaling events that may be involved in cancer progression. Thus, our MOSE-derived cell model represents a unique model for in depth mechanistic studies of ovarian cancer progression.
Comparative Metabolomics of Fruits and Leaves in a Hyperdiverse Lineage Suggests Fruits Are a Key Incubator of Phytochemical Diversification
Schneider, Gerald F.; Salazar, Diego; Hildreth, Sherry B.; Helm, Richard F.; Whitehead, Susan R. (Frontiers, 2021-08-30)
Interactions between plants and leaf herbivores have long been implicated as the major driver of plant secondary metabolite diversity. However, other plant-animal interactions, such as those between fruits and frugivores, may also be involved in phytochemical diversification. Using 12 species of Piper, we conducted untargeted metabolomics and molecular networking with extracts of fruits and leaves. We evaluated organ-specific secondary metabolite composition and compared multiple dimensions of phytochemical diversity across organs, including richness, structural complexity, and variability across samples at multiple scales within and across species. Plant organ identity, species identity, and the interaction between the two all significantly influenced secondary metabolite composition. Leaves and fruit shared a majority of compounds, but fruits contained more unique compounds and had higher total estimated chemical richness. While the relative levels of chemical richness and structural complexity across organs varied substantially across species, fruit diversity exceeded leaf diversity in more species than the reverse. Furthermore, the variance in chemical composition across samples was higher for fruits than leaves. By documenting a broad pattern of high phytochemical diversity in fruits relative to leaves, this study lays groundwork for incorporating fruit into a comprehensive and integrative understanding of the ecological and evolutionary factors shaping secondary metabolite composition at the whole-plant level.
The complete genome sequence of Staphylothermus marinus reveals differences in sulfur metabolism among heterotrophic Crenarchaeota
Anderson, Iain J.; Dharmarajan, Lakshmi; Rodriguez, Jason; Hooper, Sean; Porat, Iris; Ulrich, Luke E.; Elkins, James G.; Mavromatis, Kostas; Sun, Hui; Land, Miriam; Lapidus, Alla; Lucas, Susan; Barry, Kerrie W.; Huber, Harald; Zhulin, Igor B.; Whitman, William B.; Mukhopadhyay, Biswarup; Woese, Carl; Bristow, James; Kyrpides, Nikos C. (2009-04-02)
Background Staphylothermus marinus is an anaerobic, sulfur-reducing peptide fermenter of the archaeal phylum Crenarchaeota. It is the third heterotrophic, obligate sulfur reducing crenarchaeote to be sequenced and provides an opportunity for comparative analysis of the three genomes. Results The 1.57 Mbp genome of the hyperthermophilic crenarchaeote Staphylothermus marinus has been completely sequenced. The main energy generating pathways likely involve 2-oxoacid:ferredoxin oxidoreductases and ADP-forming acetyl-CoA synthases. S. marinus possesses several enzymes not present in other crenarchaeotes including a sodium ion-translocating decarboxylase likely to be involved in amino acid degradation. S. marinus lacks sulfur-reducing enzymes present in the other two sulfur-reducing crenarchaeotes that have been sequenced - Thermofilum pendens and Hyperthermus butylicus. Instead it has three operons similar to the mbh and mbx operons of Pyrococcus furiosus, which may play a role in sulfur reduction and/or hydrogen production. The two marine organisms, S. marinus and H. butylicus, possess more sodium-dependent transporters than T. pendens and use symporters for potassium uptake while T. pendens uses an ATP-dependent potassium transporter. T. pendens has adapted to a nutrient-rich environment while H. butylicus is adapted to a nutrient-poor environment, and S. marinus lies between these two extremes. Conclusion The three heterotrophic sulfur-reducing crenarchaeotes have adapted to their habitats, terrestrial vs. marine, via their transporter content, and they have also adapted to environments with differing levels of nutrients. Despite the fact that they all use sulfur as an electron acceptor, they are likely to have different pathways for sulfur reduction.
Correction: Mitotic-Chromosome-Based Physical Mapping of the Culex quinquefasciatus Genome.
Naumenko, Anastasia N.; Timoshevskiy, Vladimir A.; Kinney, Nicholas A.; Kokhanenko, Alina A.; deBruyn, Becky S.; Lovin, Diane D.; Stegniy, Vladimir N.; Severson, David W.; Sharakhov, Igor V.; Sharakhova, Maria V. (2015)
Correction
Differing house Finch cytokine expression responses to Original and evolved isolates of Mycoplasma gallisepticum
Vinkler, Michal; Leon, Ariel E.; Kirkpatrick, Laila T.; Dalloul, Rami A.; Hawley, Dana M. (Frontiers, 2018-01-22)
The recent emergence of the poultry bacterial pathogen Mycoplasma gallisepticum (MG) in free-living house finches (Haemorhous mexicanus), which causes mycoplasmal conjunctivitis in this passerine bird species, resulted in a rapid coevolutionary arms-race between MG and its novel avian host. Despite extensive research on the ecological and evolutionary dynamics of this host–pathogen system over the past two decades, the immunological responses of house finches to MG infection remain poorly understood. We developed seven new probe-based one-step quantitative reverse transcription polymerase chain reaction assays to investigate mRNA expression of house finch cytokine genes (IL1B, IL6, IL10, IL18, TGFB2, TNFSF15, and CXCLi2, syn. IL8L). These assays were then used to describe cytokine transcription profiles in a panel of 15 house finch tissues collected at three distinct time points during MG infection. Based on initial screening that indicated strong pro-inflammatory cytokine expression during MG infection at the periorbital sites in particular, we selected two key house finch tissues for further characterization: the nictitating membrane, i.e., the internal eyelid in direct contact with MG, and the Harderian gland, the secondary lymphoid tissue responsible for regulation of periorbital immunity. We characterized cytokine responses in these two tissues for 60 house finches experimentally inoculated either with media alone (sham) or one of two MG isolates: the earliest known pathogen isolate from house finches (VA1994) or an evolutionarily more derived isolate collected in 2006 (NC2006), which is known to be more virulent. We show that the more derived and virulent isolate NC2006, relative to VA1994, triggers stronger local inflammatory cytokine signaling, with peak cytokine expression generally occurring 3–6 days following MG inoculation. We also found that the extent of pro-inflammatory interleukin 1 beta signaling was correlated with conjunctival MG loads and the extent of clinical signs of conjunctivitis, the main pathological effect of MG in house finches. These results suggest that the pathogenicity caused by MG infection in house finches is largely mediated by host pro-inflammatory immune responses, with important implications for the dynamics of host–pathogen coevolution.
Diversity and Abundance of Ice Nucleating Strains of Pseudomonas syringae in a Freshwater Lake in Virginia, USA
Pietsch, Renee B.; Vinatzer, Boris A.; Schmale, David G. III (Frontiers, 2017-03-09)
DNA Double-Strand Breaks Are a Critical Regulator of Fear Memory Reconsolidation
Navabpour, Shaghayegh; Rogers, Jessie; McFadden, Taylor; Jarome, Timothy J. (MDPI, 2020-11-26)
Numerous studies have shown that following retrieval, a previously consolidated memory requires increased transcriptional regulation in order to be reconsolidated. Previously, it was reported that histone H3 lysine-4 trimethylation (H3K4me3), a marker of active transcription, is increased in the hippocampus after the retrieval of contextual fear memory. However, it is currently unknown how this epigenetic mark is regulated during the reconsolidation process. Furthermore, though recent evidence suggests that neuronal activity triggers DNA double-strand breaks (DSBs) in some early-response genes, it is currently unknown if DSBs contribute to the reconsolidation of a memory following retrieval. Here, using chromatin immunoprecipitation (ChIP) analyses, we report a significant overlap between DSBs and H3K4me3 in area CA1 of the hippocampus during the reconsolidation process. We found an increase in phosphorylation of histone H2A.X at serine 139 (H2A.XpS139), a marker of DSB, in the Npas4, but not c-fos, promoter region 5 min after retrieval, which correlated with increased H3K4me3 levels, suggesting that the two epigenetic marks may work in concert during the reconsolidation process. Consistent with this, in vivo siRNA-mediated knockdown of topoisomerase II β, the enzyme responsible for DSB, prior to retrieval, reduced Npas4 promoter-specific H2A.XpS139 and H3K4me3 levels and impaired long-term memory, indicating an indispensable role of DSBs in the memory reconsolidation process. Collectively, our data propose a novel mechanism for memory reconsolidation through increases in epigenetic-mediated transcriptional control via DNA double-strand breaks.
Do not feed the wildlife: associations between garbage use, aggression, and disease in banded mongooses (Mungos Mungo)
Flint, Bonnie Fairbanks; Hawley, Dana M.; Alexander, Kathleen A. (Wiley, 2016-07-25)
Urbanization and other human modifications of the landscape may indirectly affect disease dynamics by altering host behavior in ways that influence pathogen transmission. Few opportunities arise to investigate behaviorally mediated effects of human habitat modification in natural host–pathogen systems, but we provide a potential example of this phenomenon in banded mongooses (Mungos mungo), a social mammal. Our banded mongoose study population in Botswana is endemically infected with a novel Mycobacterium tuberculosis complex pathogen, M. mungi, that primarily invades the mongoose host through the nasal planum and breaks in the skin. In this system, several study troops have access to human garbage sites and other modified landscapes for foraging. Banded mongooses in our study site (N = 4 troops, ~130 individuals) had significantly higher within-troop aggression levels when foraging in garbage compared to other foraging habitats. Second, monthly rates of aggression were a significant predictor of monthly number of injuries in troops. Finally, injured individuals had a 75% incidence of clinical tuberculosis (TB) compared to a 0% incidence in visibly uninjured mongooses during the study period. Our data suggest that mongoose troops that forage in garbage may be at greater risk of acquiring TB by incurring injuries that may allow for pathogen invasion. Our study suggests the need to consider the indirect effects of garbage on behavior and wildlife health when developing waste management approaches in human-modified areas.
The dynamic response of the Arabidopsis root metabolome to auxin and ethylene is not predicted by changes in the transcriptome
Hildreth, Sherry B.; Foley, Evan E.; Muday, Gloria K.; Helm, Richard F.; Winkel, Brenda S. J. (Nature Research, 2020-01-20)
While the effects of phytohormones on plant gene expression have been well characterized, comparatively little is known about how hormones influence metabolite profiles. This study examined the effects of elevated auxin and ethylene on the metabolome of Arabidopsis roots using a high-resolution 24 h time course, conducted in parallel to time-matched transcriptomic analyses. Mass spectrometry using orthogonal UPLC separation strategies (reversed phase and HILIC) in both positive and negative ionization modes was used to maximize identification of metabolites with altered levels. The findings show that the root metabolome responds rapidly to hormone stimulus and that compounds belonging to the same class of metabolites exhibit similar changes. The responses were dominated by changes in phenylpropanoid, glucosinolate, and fatty acid metabolism, although the nature and timing of the response was unique for each hormone. These alterations in the metabolome were not directly predicted by the corresponding transcriptome data, suggesting that post-transcriptional events such as changes in enzyme activity and/or transport processes drove the observed changes in the metabolome. These findings underscore the need to better understand the biochemical mechanisms underlying the temporal reconfiguration of plant metabolism, especially in relation to the hormone-metabolome interface and its subsequent physiological and morphological effects.
EGR1 recruits TET1 to shape the brain methylome during development and upon neuronal activity
Sun, Zhixiong; Xu, Xiguang; He, Jianlin; Murray, Alexander; Sun, Ming-an; Wei, Xiaoran; Wang, Xia; McCoig, Emmarose; Xie, Evan; Jiang, Xi; Li, Liwu; Zhu, Jinsong; Chen, Jianjun; Morozov, Alexei; Pickrell, Alicia M.; Theus, Michelle H.; Xie, Hehuang David (2019-08-29)
Life experience can leave lasting marks, such as epigenetic changes, in the brain. How life experience is translated into storable epigenetic information remains largely unknown. With unbiased data-driven approaches, we predicted that Egr1, a transcription factor important for memory formation, plays an essential role in brain epigenetic programming. We performed EGR1 ChIP-seq and validated thousands of EGR1 binding sites with methylation patterns established during postnatal brain development. More specifically, these EGR1 binding sites become hypomethylated in mature neurons but remain heavily methylated in glia. We further demonstrated that EGR1 recruits a DNA demethylase TET1 to remove the methylation marks and activate downstream genes. The frontal cortices from the knockout mice lacking Egr1 or Tet1 share strikingly similar profiles in both gene expression and DNA methylation. In summary, our study reveals EGR1 programs the brain methylome together with TET1 providing new insight into how life experience may shape the brain methylome.
Elevated perfusate [Na+] increases contractile dysfunction during ischemia and reperfusion
King, D. Ryan; Padget, Rachel L.; Perry, Justin B.; Hoeker, Gregory S.; Smyth, James W.; Brown, David A.; Poelzing, Steven (2020-10-14)
Recent studies revealed that relatively small changes in perfusate sodium ([Na+](o)) composition significantly affect cardiac electrical conduction and stability in contraction arrested ex vivo Langendorff heart preparations before and during simulated ischemia. Additionally, [Na+](o) modulates cardiomyocyte contractility via a sodium-calcium exchanger (NCX) mediated pathway. It remains unknown, however, whether modest changes to [Na+](o) that promote electrophysiologic stability similarly improve mechanical function during baseline and ischemia-reperfusion conditions. The purpose of this study was to quantify cardiac mechanical function during ischemia-reperfusion with perfusates containing 145 or 155 mM Na+ in Langendorff perfused isolated rat heart preparations. Relative to 145 mM Na+, perfusion with 155 mM [Na+](o) decreased the amplitude of left-ventricular developed pressure (LVDP) at baseline and accelerated the onset of ischemic contracture. Inhibiting NCX with SEA0400 abolished LVDP depression caused by increasing [Na+](o) at baseline and reduced the time to peak ischemic contracture. Ischemia-reperfusion decreased LVDP in all hearts with return of intrinsic activity, and reperfusion with 155 mM [Na+](o) further depressed mechanical function. In summary, elevating [Na+](o) by as little as 10 mM can significantly modulate mechanical function under baseline conditions, as well as during ischemia and reperfusion. Importantly, clinical use of Normal Saline, which contains 155 mM [Na+](o), with cardiac ischemia may require further investigation.
Enhanced Mucosal Defense and Reduced Tumor Burden in Mice with the Compromised Negative Regulator IRAK-M.
Rothschild, Daniel E.; Zhang, Yao; Diao, Na; Lee, Christina K.; Chen, Keqiang; Caswell, Clayton C.; Slade, Daniel J.; Helm, Richard F.; LeRoith, Tanya; Li, Liwu; Allen, Irving C. (2016-12-03)
Aberrant inflammation is a hallmark of inflammatory bowel disease (IBD) and colorectal cancer. IRAK-M is a critical negative regulator of TLR signaling and overzealous inflammation. Here we utilize data from human studies and Irak-m(-/-) mice to elucidate the role of IRAK-M in the modulation of gastrointestinal immune system homeostasis. In human patients, IRAK-M expression is up-regulated during IBD and colorectal cancer. Further functional studies in mice revealed that Irak-m(-/-) animals are protected against colitis and colitis associated tumorigenesis. Mechanistically, our data revealed that the gastrointestinal immune system of Irak-m(-/-) mice is highly efficient at eliminating microbial translocation following epithelial barrier damage. This attenuation of pathogenesis is associated with expanded areas of gastrointestinal associated lymphoid tissue (GALT), increased neutrophil migration, and enhanced T-cell recruitment. Further evaluation of Irak-m(-/-) mice revealed a splice variant that robustly activates NF-κB signaling. Together, these data identify IRAK-M as a potential target for future therapeutic intervention.
Exogenous Auxin Elicits Changes in the Arabidopsis thaliana Root Proteome in a Time-Dependent Manner.
Slade, William O.; Ray, W. Keith; Hildreth, Sherry B.; Winkel, Brenda S. J.; Helm, Richard F. (MDPI, 2017-07-10)
Auxin is involved in many aspects of root development and physiology, including the formation of lateral roots. Improving our understanding of how the auxin response is mediated at the protein level over time can aid in developing a more complete molecular framework of the process. This study evaluates the effects of exogenous auxin treatment on the Arabidopsis root proteome after exposure of young seedlings to auxin for 8, 12, and 24 h, a timeframe permitting the initiation and full maturation of individual lateral roots. Root protein extracts were processed to peptides, fractionated using off-line strong-cation exchange, and analyzed using ultra-performance liquid chromatography and data independent acquisition-based mass spectrometry. Protein abundances were then tabulated using label-free techniques and evaluated for significant changes. Approximately 2000 proteins were identified during the time course experiment, with the number of differences between the treated and control roots increasing over the 24 h time period, with more proteins found at higher abundance with exposure to auxin than at reduced abundance. Although the proteins identified and changing in levels at each time point represented similar biological processes, each time point represented a distinct snapshot of the response. Auxin coordinately regulates many physiological events in roots and does so by influencing the accumulation and loss of distinct proteins in a time-dependent manner. Data are available via ProteomeXchange with the identifier PXD001400.
Experimental logging alters the abundance and community composition of ovipositing mosquitoes in the southern Appalachians
Hopkins, M. Camille; Thomason, Courtney A.; Brown, Bryan L.; Kirkpatrick, Laila T.; Paulson, Sally L.; Hawley, Dana M. (2018-08)
1. The loss of intact forest via logging can influence vector-borne disease dynamics in part by altering the abundance or diversity of mosquito species. Using an experimental field approach, we characterised how two types of logging (clearcut and repeat-entry shelterwood) affected temperate forest mosquito abundance and diversity in southwestern Virginia. 2.From May to September in 2008-2010, infusion-baited gravid traps were used to collect ovipositing female mosquitoes across experimental forest plots that varied in logging treatment. Of the 29680 collected adult female mosquitoes, the three dominant taxa captured were Aedes triseriatus (55%), Aedes japonicus (21%), and Culex pipiens/restuans (20%). 3. Logging treatment had a significant effect on the overall number of female mosquitoes caught per trap night, with lower average abundance of females on both logged treatments relative to two types of unlogged, control plots. When the three most abundant mosquito species were examined separately, logging treatment significantly influenced the abundance of both Aedes species, but did not significantly affect C. pipiens/restuans abundance. 4. Logging treatment did not influence the richness or diversity of mosquito species captured in gravid traps. However, logging treatment significantly altered the multivariate community composition of captured mosquitoes, an effect probably mediated by differential species-specific impacts of logging on abundance. 5. Overall, the results of the present study suggest that the risk of arboviruses transmitted by container-breeding Aedes species may be lower following a logging event in Appalachian forests because of reduced A. japonicus and A. triseriatus abundance with logging.
Expression of host defense peptides in the intestine of Eimeria-challenged chickens
Su, S.; Dwyer, D. M.; Miska, Kate B.; Fetterer, Raymond H.; Jenkins, Mark C.; Wong, Eric A. (2017-07)
Avian coccidiosis is caused by the intracellular protozoan Eimeria, which produces intestinal lesions leading to weight gain depression. Current control methods include vaccination and anticoccidial drugs. An alternative approach involves modulating the immune system. The objective of this study was to profile the expression of host defense peptides such as avian beta-defensins (AvBDs) and liver expressed antimicrobial peptide 2 (LEAP2), which are part of the innate immune system. The mRNA expression of AvBD family members 1, 6, 8, 10, 11, 12, and 13 and LEAP2 was examined in chickens challenged with either E. acervulina, E. maxima, or E. tenella. The duodenum, jejunum, ileum, and ceca were collected 7 d post challenge. In study 1, E. acervulina challenge resulted in down-regulation of AvBD1, AvBD6, AvBD10, AvBD11, AvBD12, and AvBD13 in the duodenum. E. maxima challenge caused down-regulation of AvBD6, AvBD10, and AvBD11 in the duodenum, down-regulation of AvBD10 in the jejunum, but up-regulation of AvBD8 and AvBD13 in the ceca. E. tenella challenge showed no change in AvBD expression in any tissue. In study 2, which involved challenge with only E. maxima, there was down-regulation of AvBD1 in the ileum, AvBD11 in the jejunum and ileum, and LEAP2 in all 3 segments of the small intestine. The expression of LEAP2 was further examined by in situ hybridization in the jejunum of chickens from study 2. LEAP2 mRNA was expressed similarly in the enterocytes lining the villi, but not in the crypts of control and Eimeria challenged chickens. The lengths of the villi in the Eimeria challenged chickens were less than those in the control chickens, which may in part account for the observed down-regulation of LEAP2 mRNA quantified by PCR. Overall, the AvBD response to Eimeria challenge was not consistent; whereas LEAP2 was consistently down-regulated, which suggests that LEAP2 plays an important role in modulating an Eimeria infection.

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