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1232 full-text articles. Page 1 of 45.

Genome Wide Co-Expression Among The Starch Debranching Enzyme Genes Atisa1, Atisa2, And Atisa3 In Arabidopsis Thaliana, Ling Li, Hilal Ilarslan, Martha G. James, Alan M. Myers, Eve Syrkin Wurtele 2017 Iowa State University

Genome Wide Co-Expression Among The Starch Debranching Enzyme Genes Atisa1, Atisa2, And Atisa3 In Arabidopsis Thaliana, Ling Li, Hilal Ilarslan, Martha G. James, Alan M. Myers, Eve Syrkin Wurtele

Eve Wurtele

Each of four starch debranching enzymes (DBE) is distinct and highly conserved across the plant kingdom; however, the specific functions of these proteins in carbohydrate metabolism are not well understood. DBEs function in both biosynthesis and degradation of starch, and two have been shown to function as multimers in various quarternary structures that can contain one or more DBE proteins, i.e. ISA1 homomultimers and ISA1/ISA2 heteromultimers. This study characterizes potential functional relationships between the three isoamylase-type DBE proteins (ISA) of Arabidopsis using a comprehensive bioinformatics analysis and promoter fusion approach to determine tissue-, subcellular-, and temporal specificity of ...


Jennifer Maurer Phd Thesis.Pdf, Jennifer Maurer 2017 University of Massachusetts Medical School

Jennifer Maurer Phd Thesis.Pdf, Jennifer Maurer

Jennifer Maurer


Signaling cascades, such as the extracellular signal-regulated kinase (ERK) pathway, play vital roles in early vertebrate development. Signals through these pathways are initiated by a growth factor or hormone, are transduced through a kinase cascade, and result in the expression of specific downstream genes that promote cellular proliferation, growth, or differentiation.Tight regulation of these signals is provided by positive or negative modulators at varying levels in the pathway, and is required for proper development and function. Two members of the dual-specificity phosphatase (Dusp) family, dusp6 and dusp2, are believed to be negative regulators of the ERK pathway and are ...


Characterization Of Acaricide Resistance, Plant-Mediated Rnai Against Two-Spotted Spider Mites (Tetranychus Urticae Koch), And Assessing Off- And Non-Target Effects, Hooman Hosseinzadeh Namin 2017 The University of Western Ontario

Characterization Of Acaricide Resistance, Plant-Mediated Rnai Against Two-Spotted Spider Mites (Tetranychus Urticae Koch), And Assessing Off- And Non-Target Effects, Hooman Hosseinzadeh Namin

Electronic Thesis and Dissertation Repository

The two-spotted spider mite (TSSM), Tetranychus urticae (Koch), is one of the most damaging agricultural pests in the world. It feeds on over 150 crops, causing considerable yield losses in greenhouses and agricultural fields. Currently, using synthetic acaricides is the main method to control TSSM. However, it can develop resistance to acaricides with repeated exposure, and typically resistance can occur within two to four years. To understand the underlying mechanisms of spider mite adaptation to acaricides is an essential part of resistance management strategy. The resistance ratio of the pyridaben-selected strain compared with the pre-selection strain was estimated at greater ...


Role Of Nitric Oxide In Embryonic Heart Development And Adult Aortic Valve Disease, Yin Liu 2017 The University of Western Ontario

Role Of Nitric Oxide In Embryonic Heart Development And Adult Aortic Valve Disease, Yin Liu

Yin Liu

Congenital heart disease (CHD) is the most common birth defect in infants. Identifying factors that are critical to embryonic heart development or CHDs in general could further our understanding of the disease and may lead to new strategies of its prevention and treatment. Endothelial nitric oxide synthase (NOS3/eNOS) is known for many important biological functions including vasodilation, vascular homeostasis and angiogenesis. Previous studies have shown that deficiency in NOS3 results in congenital septal defects, cardiac hypertrophy and postnatal heart failure. In addition, NOS3 is pivotal to morphogenesis of aortic valve and myocardial capillary development. The aim of my thesis ...


Effect Of Macrolide Usage On Emergence Of Erythromycin-Resistant Campylobacter Isolates In Chickens, Jun Lin, Meiguan Yan, Orhan Sahin, Sonia Pereira, Yun-Juan Chang, Qijing Zhang, Qijing Zhang 2017 University of Tennessee, Knoxville

Effect Of Macrolide Usage On Emergence Of Erythromycin-Resistant Campylobacter Isolates In Chickens, Jun Lin, Meiguan Yan, Orhan Sahin, Sonia Pereira, Yun-Juan Chang, Qijing Zhang, Qijing Zhang

Qijing Zhang

In this work we conducted both in vitro and in vivo experiments to examine the development and mechanisms of erythromycin (Ery) resistance in Campylobacter jejuni and Campylobacter coli. In vitro plating revealed that both Campylobacter species had similar but low spontaneous mutation frequencies (3 × 10−9 to −10) for Ery resistance. Chickens infected with C. jejuni or C. coli were subjected to single or multiple treatments with medicated water containing tylosin (0.53 g/liter), which transiently reduced the level of Campylobacter colonization but did not select for Ery-resistant (Eryr) mutants in the treated birds. However, when tylosin was given ...


The Campylobacter Jejuni Response Regulator, Cbrr, Modulates Sodium Deoxycholate Resistance And Chicken Colonization, Brian H. Raphael, Sonia Pereira, Gary A. Flom, Qijing Zhang, Julian M. Ketley, Michael E. Konkel 2017 Washington State University

The Campylobacter Jejuni Response Regulator, Cbrr, Modulates Sodium Deoxycholate Resistance And Chicken Colonization, Brian H. Raphael, Sonia Pereira, Gary A. Flom, Qijing Zhang, Julian M. Ketley, Michael E. Konkel

Qijing Zhang

Two-component regulatory systems play a major role in the physiological response of bacteria to environmental stimuli. Such systems are composed of a sensor histidine kinase and a response regulator whose ultimate function is to affect the expression of target genes. Response regulator mutants of Campylobacter jejuni strain F38011 were screened for sensitivity to sodium deoxycholate. A mutation in Cj0643, which encodes a response regulator with no obvious cognate histidine kinase, resulted in an absence of growth on plates containing a subinhibitory concentration of sodium deoxcholate (1%, wt/vol). In broth cultures containing 0.05% (wt/vol) sodium deoxycholate, growth of ...


Salicylate Functions As An Efflux Pump Inducer And Promotes The Emergence Of Fluoroquinolone-Resistant Campylobacter Jejuni Mutants, Zhangqi Shen, Xiao-Ying Pu, Qijing Zhang 2017 Iowa State University

Salicylate Functions As An Efflux Pump Inducer And Promotes The Emergence Of Fluoroquinolone-Resistant Campylobacter Jejuni Mutants, Zhangqi Shen, Xiao-Ying Pu, Qijing Zhang

Qijing Zhang

Salicylate, a nonsteroidal anti-inflammatory compound, has been shown to increase the resistance of Campylobacter to antimicrobials. However, the molecular mechanism underlying salicylate-induced resistance has not yet been established. In this study, we determined how salicylate increases antibiotic resistance and evaluated its impact on the development of fluoroquinolone-resistant Campylobacter mutants. Transcriptional fusion assays, real-time quantitative reverse transcription-PCR (RT-PCR), and immunoblotting assays consistently demonstrated the induction of the CmeABC multidrug efflux pump by salicylate. Electrophoretic mobility shift assays further showed that salicylate inhibits the binding of CmeR (a transcriptional repressor of the TetR family) to the promoter DNA of cmeABC, suggesting that ...


Identification Of An Arsenic Resistance And Arsenic-Sensing System In Campylobacter Jejuni, Liping Wang, Byeonghwa Jeon, Orhan Sahin, Qijing Zhang 2017 Iowa State University

Identification Of An Arsenic Resistance And Arsenic-Sensing System In Campylobacter Jejuni, Liping Wang, Byeonghwa Jeon, Orhan Sahin, Qijing Zhang

Qijing Zhang

Arsenic is commonly present in the natural environment and is also used as a feed additive for animal production. Poultry is a major reservoir for Campylobacter jejuni, a major food-borne human pathogen causing gastroenteritis. It has been shown that Campylobacter isolates from poultry are highly resistant to arsenic compounds, but the molecular mechanisms responsible for the resistance have not been determined, and it is unclear if the acquired arsenic resistance affects the susceptibility of Campylobacter spp. to other antimicrobials. In this study, we identified a four-gene operon that contributes to arsenic resistance in Campylobacter. This operon encodes a putative membrane ...


Role Of Cj1211 In Natural Transformation And Transfer Of Antibiotic Resistance Determinants In Campylobacter Jejuni, Byeonghwa Jeon, Wayne Muraoka, Orhan Sahin, Qijing Zhang 2017 Iowa State University

Role Of Cj1211 In Natural Transformation And Transfer Of Antibiotic Resistance Determinants In Campylobacter Jejuni, Byeonghwa Jeon, Wayne Muraoka, Orhan Sahin, Qijing Zhang

Qijing Zhang

Campylobacter jejuni, an important food-borne human pathogen, is increasingly resistant to antimicrobials. Natural transformation is considered to be a main mechanism for mediating the transfer of genetic materials encoding antibiotic resistance determinants in C. jejuni, but direct evidence for this notion is still lacking. In this study, we determined the role of Cj1211 in natural transformation and in the development of antibiotic resistance in C. jejuni. Insertional mutagenesis of Cj1211, a Helicobacter pylori ComH3 homolog, abolished natural transformation in C. jejuni. In vitro coculture of C. jejuni strains carrying either kanamycin or tetracycline resistance markers demonstrated the development of progenies ...


Bile Salts Modulate Expression Of The Cmeabc Multidrug Efflux Pump In Campylobacter Jejuni, Jun Lin, Cédric Cagliero, Baoqing Guo, Yi-Wen Barton, Marie-Christine Maurel, Sophie Payot, Qijing Zhang 2017 Iowa State University

Bile Salts Modulate Expression Of The Cmeabc Multidrug Efflux Pump In Campylobacter Jejuni, Jun Lin, Cédric Cagliero, Baoqing Guo, Yi-Wen Barton, Marie-Christine Maurel, Sophie Payot, Qijing Zhang

Qijing Zhang

CmeABC, a multidrug efflux pump, is involved in the resistance of Campylobacter jejuni to a broad spectrum of antimicrobial agents and is essential for Campylobacter colonization in animal intestine by mediating bile resistance. Previously, we have shown that expression of this efflux pump is under the control of a transcriptional repressor named CmeR. Inactivation of CmeR or mutation in the cmeABC promoter (PcmeABC) region derepresses cmeABC, leading to overexpression of this efflux pump. However, it is unknown if the expression of cmeABC can be conditionally induced by the substrates it extrudes. In this study, we examined the expression of ...


Cmer Functions As A Transcriptional Repressor For The Multidrug Efflux Pump Cmeabc In Campylobacter Jejuni, Jun Lin, Masato Akiba, Orhan Sahin, Qijing Zhang 2017 Iowa State University

Cmer Functions As A Transcriptional Repressor For The Multidrug Efflux Pump Cmeabc In Campylobacter Jejuni, Jun Lin, Masato Akiba, Orhan Sahin, Qijing Zhang

Qijing Zhang

CmeABC, a resistance-nodulation-division (RND) type of efflux pump, contributes to Campylobacter resistance to a broad spectrum of antimicrobial agents and is also essential for Campylobacter colonization of the animal intestinal tract by mediation of bile resistance. As one of the main systems for Campylobacter adaptation to different environments, CmeABC is likely subject to control by regulatory elements. We describe the identification of a transcriptional repressor for CmeABC. Insertional mutagenesis of cmeR, an open reading frame immediately upstream of the cmeABC operon, resulted in overexpression of cmeABC, as determined by transcriptional fusion (PcmeABC-lacZ) and immunoblotting with CmeABC-specific antibodies. Overexpression of the ...


Distribution Of The Multidrug Resistance Gene Cfr In Staphylococcus Species Isolates From Swine Farms In China, Yang Wang, Wanjiang Zhang, Juan Wang, Congming Wu, Zhangqi Shen, Xiao Fu, Yang Yan, Qijing Zhang, Stefan Schwarz, Jianzhong Shen 2017 China Agricultural University

Distribution Of The Multidrug Resistance Gene Cfr In Staphylococcus Species Isolates From Swine Farms In China, Yang Wang, Wanjiang Zhang, Juan Wang, Congming Wu, Zhangqi Shen, Xiao Fu, Yang Yan, Qijing Zhang, Stefan Schwarz, Jianzhong Shen

Qijing Zhang

A total of 149 porcine Staphylococcus isolates with florfenicol MICs of ≥16 μg/ml were screened for the presence of the multiresistance gene cfr, its location on plasmids, and its genetic environment. In total, 125 isolates carried either cfr (16 isolates), fexA (92 isolates), or both genes (17 isolates). The 33 cfr-carrying staphylococci, which included isolates of the species Staphylococcus cohnii, S. arlettae, and S. saprophyticus in which the cfr gene has not been described before, exhibited a wide variety of SmaI pulsed-field gel electrophoresis patterns. In 18 cases, the cfr gene was located on plasmids. Four different types ...


Cj0011c, A Periplasmic Single- And Double-Stranded Dna-Binding Protein, Contributes To Natural Transformation In Campylobacter Jejuni, Byeonghwa Jeon, Qijing Zhang 2017 Iowa State University

Cj0011c, A Periplasmic Single- And Double-Stranded Dna-Binding Protein, Contributes To Natural Transformation In Campylobacter Jejuni, Byeonghwa Jeon, Qijing Zhang

Qijing Zhang

Campylobacter jejuni is an important bacterial pathogen causing gastroenteritis in humans. C. jejuni is capable of natural transformation, which is considered a major mechanism mediating horizontal gene transfer and generating genetic diversity. Despite recent efforts to elucidate the transformation mechanisms of C. jejuni, the process of DNA binding and uptake in this organism is still not well understood. In this study, we report a previously unrecognized DNA-binding protein (Cj0011c) in C. jejuni that contributes to natural transformation. Cj0011c is a small protein (79 amino acids) with a partial sequence homology to the C-terminal region of ComEA in Bacillus subtilis. Cj0011c ...


Characterization Of A Novel Mitochondrial Plasmid In Brassica, Mackenzie Strehle 2017 University of Nebraska - Lincoln

Characterization Of A Novel Mitochondrial Plasmid In Brassica, Mackenzie Strehle

UCARE Research Products

Possessing some of the largest and most complex genomes of any eukaryotic organelles, plant mitochondria are notorious for their rapidly rearranging genetic framework. In addition to containing a large and complex mitochondrial genome, the mitochondria of several plants in the genus Brassica have also been shown to contain an independent, self-replicating linear plasmid. Interestingly, the plasmid appears to be able to move independently between the cytoplasm and the mitochondria, and it can be paternally inherited, unlike the rest of the mitochondrial genome. The plasmid also has features similar to those of adenoviruses, including terminal inverted repeats and covalently bound proteins ...


Transferable Multiresistance Plasmids Carrying Cfr In Enterococcus Spp. From Swine And Farm Environment, Yang Liu, Yang Wang, Stefan Schwarz, Yun Li, Zhangqi Shen, Qijing Zhang, Congming Wu, Jianzhong Shen 2017 China Agricultural University

Transferable Multiresistance Plasmids Carrying Cfr In Enterococcus Spp. From Swine And Farm Environment, Yang Liu, Yang Wang, Stefan Schwarz, Yun Li, Zhangqi Shen, Qijing Zhang, Congming Wu, Jianzhong Shen

Qijing Zhang

Seventy-seven porcine Enterococcus isolates with florfenicol MICs of ≥16 μg of were/ml screened for the presence of the multiresistance gene cfr, its location on plasmids, and its genetic environment. Three isolates—Enterococcus thailandicus 3-38 (from a porcine rectal swab collected at a pig farm), Enterococcus thailandicus W3, and Enterococcus faecalis W9-2 (the latter two from sewage at a different farm), carried the cfr gene. The SmaI pulsed-field gel electrophoresis patterns of the three isolates differed distinctly. In addition, E. faecalis W9-2 was assigned to a new multilocus sequence type ST469. Mating experiments and Southern blot analysis indicated that cfr ...


Synergistic Effects Of Anti-Cmea And Anti-Cmeb Peptide Nucleic Acids On Sensitizing Campylobacter Jejuni To Antibiotics, Yang Mu, Zhangqi Shen, Byeonghwa Jeon, Lei Dai, Qijing Zhang 2017 Iowa State University

Synergistic Effects Of Anti-Cmea And Anti-Cmeb Peptide Nucleic Acids On Sensitizing Campylobacter Jejuni To Antibiotics, Yang Mu, Zhangqi Shen, Byeonghwa Jeon, Lei Dai, Qijing Zhang

Qijing Zhang

The CmeABC efflux pump in Campylobacter jejuni confers resistance to structurally divergent antimicrobials, and inhibition of CmeABC represents a promising strategy to control antibiotic-resistant Campylobacter. Antisense peptide nucleic acids (PNAs) targeting the three components of CmeABC were evaluated for inhibition of CmeABC expression. The result revealed a synergistic effect of the PNAs targeting CmeA and CmeB on sensitizing C. jejuni to antibiotics. This finding further demonstrates the feasibility of using PNAs to potentiate antibiotics against antibiotic-resistant Campylobacter.


Mutational And Transcriptomic Changes Involved In The Development Of Macrolide Resistance In Campylobacter Jejuni, Haihong Hao, Zonghui Yuan, Zhangqi Shen, Jing Han, Orhan Sahin, Peng Liu, Qijing Zhang 2017 Iowa State University

Mutational And Transcriptomic Changes Involved In The Development Of Macrolide Resistance In Campylobacter Jejuni, Haihong Hao, Zonghui Yuan, Zhangqi Shen, Jing Han, Orhan Sahin, Peng Liu, Qijing Zhang

Qijing Zhang

Macrolide antibiotics are important for clinical treatment of infections caused by Campylobacter jejuni. Development of resistance to this class of antibiotics in Campylobacter is a complex process, and the dynamic molecular changes involved in this process remain poorly defined. Multiple lineages of macrolide-resistant mutants were selected by stepwise exposure of C. jejuni to escalating doses of erythromycin or tylosin. Mutations in target genes were determined by DNA sequencing, and the dynamic changes in the expression of antibiotic efflux transporters and the transcriptome of C. jejuni were examined by real-time reverse transcription-PCR, immunoblotting, and DNA microarray analysis. Multiple types of mutations ...


Identification Of A Novel Membrane Transporter Mediating Resistance To Organic Arsenic In Campylobacter Jejuni, Zhangqi Shen, Taradon Luangtongkum, Zhiyi Qiang, Byeonghwa Jeon, Liping Wang, Qijing Zhang 2017 Iowa State University

Identification Of A Novel Membrane Transporter Mediating Resistance To Organic Arsenic In Campylobacter Jejuni, Zhangqi Shen, Taradon Luangtongkum, Zhiyi Qiang, Byeonghwa Jeon, Liping Wang, Qijing Zhang

Qijing Zhang

Although bacterial mechanisms involved in the resistance to inorganic arsenic are well understood, the molecular basis for organic arsenic resistance has not been described. Campylobacter jejuni, a major food-borne pathogen causing gastroenteritis in humans, is highly prevalent in poultry and is reportedly resistant to the arsenic compound roxarsone (4-hydroxy-3-nitrobenzenearsonic acid), which has been used as a feed additive in the poultry industry for growth promotion. In this study, we report the identification of a novel membrane transporter (named ArsP) that contributes to organic arsenic resistance in Campylobacter. ArsP is predicted to be a membrane permease containing eight transmembrane helices, distinct ...


Emergence Of Multidrug-Resistant Campylobacter Species Isolates With A Horizontally Acquired Rrna Methylase, Yang Wang, Maojun Zhang, Fengru Deng, Zhangqi Shen, Congming Wu, Jianzhong Zhang, Qijing Zhang, Jianzhong Shen 2017 China Agricultural University

Emergence Of Multidrug-Resistant Campylobacter Species Isolates With A Horizontally Acquired Rrna Methylase, Yang Wang, Maojun Zhang, Fengru Deng, Zhangqi Shen, Congming Wu, Jianzhong Zhang, Qijing Zhang, Jianzhong Shen

Qijing Zhang

Antibiotic-resistant Campylobacter constitutes a serious threat to public health, and resistance to macrolides is of particular concern, as this class of antibiotics is the drug of choice for clinical therapy of campylobacteriosis. Very recently, a horizontally transferrable macrolide resistance mediated by the rRNA methylase gene erm(B) was reported in a Campylobacter coli isolate, but little is known about the dissemination of erm(B) among Campylobacter isolates and the association of erm(B)-carrying isolates with clinical disease. To address this question and facilitate the control of antibiotic-resistant Campylobacter, we determined the distribution of erm(B) in 1,554 C ...


High Incidence And Endemic Spread Of Ndm-1-Positive Enterobacteriaceae In Henan Province, China, Shangshang Qin, Ying Fu, Qijing Zhang, Hui Qi, Jian Guo Wen, Hui Xu, Lijuan Xu, Li Zeng, Hao Tian, Lijuan Rong, Yonghong Li, Lihong Shan, Hongde Xu, Yunsong Yu, Xianju Feng, Hong-Min Liu 2017 Zhengzhou University

High Incidence And Endemic Spread Of Ndm-1-Positive Enterobacteriaceae In Henan Province, China, Shangshang Qin, Ying Fu, Qijing Zhang, Hui Qi, Jian Guo Wen, Hui Xu, Lijuan Xu, Li Zeng, Hao Tian, Lijuan Rong, Yonghong Li, Lihong Shan, Hongde Xu, Yunsong Yu, Xianju Feng, Hong-Min Liu

Qijing Zhang

The emergence and spread of New Delhi metallo-β-lactamase 1 (NDM-1)-producing carbapenem-resistant Enterobacteriaceae (CRE) present an urgent threat to human health. In China, the blaNDM-1 gene has been reported mostly in Acinetobacter spp. but is rarely found in Enterobacteriaceae. Here, we report a high incidence and endemic spread of NDM-1-producing CRE in Henan Province in China. Sixteen (33.3%) of the 48 CRE isolates obtained from patients during June 2011 to July 2012 were positive for blaNDM-1, and the gene was found to be carried on plasmids of various sizes (∼55 to ∼360 kb). These plasmids were readily transferrable to ...


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