Conclusive Evidence Of Replication Of A Plant Virus In Honeybees Is Lacking, 2017 Iowa State University
Conclusive Evidence Of Replication Of A Plant Virus In Honeybees Is Lacking, W. Allen Miller, Jimena Carrillo-Tripp, Bryony C. Bonning, Adam G. Dolezal, Amy L. Toth
W. Allen Miller
The recent article by Li et al. (1) lacks adequate evidence to support the authors’ assertion that a plant virus propagates or replicates in honeybees. Instead, it is possible that tobacco ringspot virus (TRSV) virions associate with the honeybee and parasitic Varroa mites in the absence of TRSV replication.
Increasing Diterpene Yield With A Modular Metabolic Engineering System In E. Coli: Comparison Of Mev And Mep Isoprenoid Precursor Pathway Engineering, Dana Morrone, Luke Lowry, Mara K. Determan, David M. Hershey, Meimei Xu, Reuben J. Peters
Reuben J. Peters
Engineering biosynthetic pathways in heterologous microbial host organisms offers an elegant approach to pathway elucidation via the incorporation of putative biosynthetic enzymes and characterization of resulting novel metabolites. Our previous work in Escherichia coli demonstrated the feasibility of a facile modular approach to engineering the production of labdane-related diterpene (20 carbon) natural products. However, yield was limited (<0.1 mg/L), presumably due to reliance on endogenous production of the isoprenoid precursors dimethylallyl diphosphate and isopentenyl diphosphate. Here, we report incorporation of either a heterologous mevalonate pathway (MEV) or enhancement of the endogenous methyl erythritol phosphate pathway (MEP) with our modular metabolic engineering system. With MEP pathway enhancement, it was found that pyruvate supplementation of rich media and simultaneous overexpression of three genes (idi, dxs, and dxr) resulted in the greatest increase in diterpene yield, indicating distributed metabolic control within this pathway. Incorporation of a heterologous MEV pathway in bioreactor grown cultures resulted in significantly higher yields than MEP pathway enhancement. We have established suitable growth conditions for diterpene production levels ranging from 10 to >100 mg/L of E. coli culture. These amounts are sufficient for nuclear magnetic resonance analyses, enabling characterization of enzymatic products and hence, pathway elucidation. Furthermore, these results represent an up to >1,000-fold improvement in diterpene production from our facile, modular platform ...0.1>
Spatial Variation In Carbon And Nitrogen In Cultivated Soils In Henan Province, China: Potential Effect On Crop Yield, Xuelin Zhang, Qun Wang, Frank S. Gilliam, Yilun Wang, Feina Cha, Chaohai Li
Improved management of soil carbon (C) and nitrogen (N) storage in agro-ecosystems represents an important strategy for ensuring food security and sustainable agricultural development in China. Accurate estimates of the distribution of soil C and N stores and their relationship to crop yield are crucial to developing appropriate cropland management policies. The current study examined the spatial variation of soil organic C (SOC), total soil N (TSN), and associated variables in the surface layer (0–40 cm) of soils from intensive agricultural systems in 19 counties within Henan Province, China, and compared these patterns with crop yield. Mean soil C ...
Functional Characterization Of A Lipoprotein-Encoding Operon In Campylobacter Jejuni, 2017 Iowa State University
Functional Characterization Of A Lipoprotein-Encoding Operon In Campylobacter Jejuni, Mayumi Oakland, Byeonghwa Jeon, Orhan Sahin, Zhangqi Shen, Qijing Zhang
Background Bacterial lipoproteins have important functions in bacterial pathogenesis and physiology. In Campylobacter jejuni, a major foodborne pathogen causing gastroenteritis in humans, the majority of lipoproteins have not been functionally characterized. Previously, we showed by DNA microarray that CmeR, a transcriptional regulator repressing the expression of the multidrug efflux pump CmeABC, modulates the expression of a three-gene operon (cj0089, cj0090, and cj0091) encoding a cluster of lipoproteins in C. jejuni. Methodology/Principal Findings In this work, we characterized the function and regulation of the cj0089-cj0090-cj0091 operon. In contrast to the repression of cmeABC, CmeR activates the expression of the lipoprotein ...
Key Role Of Mfd In The Development Of Fluoroquinolone Resistance In Campylobacter Jejuni, 2017 Iowa State University
Key Role Of Mfd In The Development Of Fluoroquinolone Resistance In Campylobacter Jejuni, Jing Han, Orhan Sahin, Yi-Wen Barton, Qijing Zhang
Campylobacter jejuni is a major food-borne pathogen and a common causative agent of human enterocolitis. Fluoroquinolones are a key class of antibiotics prescribed for clinical treatment of enteric infections including campylobacteriosis, but fluoroquinolone-resistant Campylobacterreadily emerges under the antibiotic selection pressure. To understand the mechanisms involved in the development of fluoroquinolone-resistant Campylobacter, we compared the gene expression profiles of C. jejuni in the presence and absence of ciprofloxacin using DNA microarray. Our analysis revealed that multiple genes showed significant changes in expression in the presence of a suprainhibitory concentration of ciprofloxacin. Most importantly, ciprofloxacin induced the expression of mfd, which encodes ...
Molecular Mechanisms Of Mycoplasma Hyopneumoniae Adherence To Swine Respiratory Epithelial Cells, 2017 Iowa State University
Molecular Mechanisms Of Mycoplasma Hyopneumoniae Adherence To Swine Respiratory Epithelial Cells, Qijing Zhang
A microtiter plate adherence assay for Mycoplasma hyopneumoniae was established by using purified swine tracheal cilia which are the natural targets for the mycoplasma. M. hyopneumoniae bound specifically to solubilized cilia immobilized onto microtiter plates. Dextran sulfate, heparin, chondroitin sulfate, laminin, mucin, and fucoidan significantly inhibited binding of the mycoplasmas to cilia. Heparin, mucin, fucoidan, and chondroitin sulfate interacted with the adhesins on the surface of mycoplasmas, whereas laminin blocked the receptors in cilia. Treatment of cilia with neuraminidase appeared to promote adherence of the mycoplasmas; whereas, treatment of cilia with sodium metaperiodate decreased the binding. In the second study ...
Identification Of New Delhi Metallo-Β-Lactamase 1 In Acinetobacter Lwoffii Of Food Animal Origin, 2017 China Agricultural University
Identification Of New Delhi Metallo-Β-Lactamase 1 In Acinetobacter Lwoffii Of Food Animal Origin, Yang Wang, Conming Wu, Qijing Zhang, Jing Qi, Hebing Liu, Yu Wang, Tao He, Licai Ma, Jing Lai, Zhangqi Shen, Yuqing Liu, Jianzhong Shen
To investigate the presence of metallo-β-lactamase (MBL) genes and the genetic environment of the New Delhi metallo-β-lactamase gene blaNDM-1 in bacteria of food animal origin.
Gram-negative bacteria with low susceptibility to imipenem (MIC>8 µg/mL) were isolated from swab samples collected from 15 animal farms and one slaughterhouse in eastern China. These bacteria were selected for phenotypic and molecular detection of known MBL genes and antimicrobial susceptibility testing. For the blaNDM-1 positive isolate, conjugation and transformation experiments were carried out to assess plasmid transfer. Southern blotting was conducted to localize the blaNDM-1 genes, and DNA ...
Antibiotic Resistance Modulation And Modes Of Action Of (-)-Α-Pinene In Campylobacter Jejuni, 2017 University of Ljubljana
Antibiotic Resistance Modulation And Modes Of Action Of (-)-Α-Pinene In Campylobacter Jejuni, Jasna Kovač, Katarina Šimunović, Zuowei Wu, Anja Klančnik, Franz Bucar, Qijing Zhang, Sonja Smole Možina
The aim of the study was to investigate the mode of action of (-)-α-pinene in terms of its modulation of antibiotic resistance in Campylobacter jejuni. Broth microdilution and ethidium bromide accumulation assays were used to evaluate the (-)-α-pinene antimicrobial activity, modulation of antimicrobial resistance, and inhibition of antimicrobial efflux. The target antimicrobial efflux systems were identified using an insertion mutagenesis approach, and C.jejuni adaptation to (-)-α-pinene was evaluated using DNA microarrays. Knock-out mutants of the key up-regulated transcriptional regulators hspR and hrcA were constructed to investigate their roles in C. jejuni adaptation to several stress factors, including osmolytes, and ...
Relating Watershed Characteristics To Elevated Stream Escherichia Coli Levels In Agriculturally Dominated Landscapes: An Iowa Case Study, Conrad Brendel, Michelle L. Soupir
Michelle L. Soupir
Fecal Indicator Bacteria (FIB) such as Escherichia coli (E. coli) are a leading cause of surface water impairments in the United States. However, the relative impacts of different watershed characteristics on microbial water quality in agriculturally dominated watersheds are unclear. Spatial and statistical analyses were utilized to examine relationships between watershed characteristics and FIB and a multiple regression model was created. Geometric mean E. coli concentration data were obtained for 395 ambient water quality monitoring locations in Iowa. Watersheds were delineated for thirty randomly selected monitoring locations and drainage areas ranged from 93 to 1.1 million hectares. Watershed characteristics ...
Isotuberculosinol: The Unusual Case Of An Immunomodulatory Diterpenoid From Mycobacterium Tuberculosis, 2017 Winona State University
Isotuberculosinol: The Unusual Case Of An Immunomodulatory Diterpenoid From Mycobacterium Tuberculosis, Francis M. Mann, Reuben J. Peters
Reuben J. Peters
The actinomycetes family of bacteria is classically considered a rich source of natural products . It is often suggested that such compounds have been selected by evolution to have biological activity . For example, given the microbial-rich soil environment of the actinomycetes native habitat, their natural products have been suggested to serve in chemical warfare and/or signaling, which has been further connected to their leading role in providing pharmaceutically relevant antibiotic agents . Nevertheless, surprisingly few of these molecules have been definitively assigned specific physiological roles in the native producing bacteria.
Magnesium Depletion Triggers Production Of An Immune Modulating Diterpenoid In Mycobacterium Tuberculosis, 2017 Iowa State University
Magnesium Depletion Triggers Production Of An Immune Modulating Diterpenoid In Mycobacterium Tuberculosis, Francis M. Mann, Brian C. Vanderven, Reuben J. Peters
Reuben J. Peters
Mycobacterium tuberculosis (Mtb) is the causative agent of the human disease Tuberculosis, and remains a worldwide health threat responsible for ~1.7 million deaths annually. During infection, Mtb prevents acidification of the engulfing phagosome, thus blocking endocytic progression and eventually leading to stable residence. The diterpenoid metabolite isotuberculosinol (isoTb) exhibits biological activity indicative of a role in this early arrest of phagosome maturation. Presumably, isoTb production should be induced by phagosomal entry. However, the relevant enzymatic genes are not transcriptionally upregulated during engulfment. Previous examination of the initial biosynthetic enzyme (Rv3377c/MtHPS) involved in isoTb biosynthesis revealed striking inhibition by ...
Genetic Diversity Of Mycobacteriophages And The Unique Abilities Of Cluster K, 2017 Georgia College and State University
Genetic Diversity Of Mycobacteriophages And The Unique Abilities Of Cluster K, Shea A. Morris
Mycobacteriophage are a diverse set of viruses that infect a broad host range of mycobacterium. Genome analysis of this phage group reveals its diversity and provides evidence that they have experienced substantial horizontal gene transfer Collectively they have a large range of host bacteria they can infect, although each viral type may have a limited host range. However, this range is easily expanded and constantly changing in nature by mutation within and between virus types. These phages can lytically destroy their host mycobacteria, and it is this viral ability that have many mycobacteriophage researchers excited about the potential that phage ...
The Role Of Dietary Highly Unsaturated N-3 Fatty Acids In Northern Quahogs, Mercenaria Mercenaria, Through Decreasing Temperature, 2017 The Graduate Center, City University of New York
The Role Of Dietary Highly Unsaturated N-3 Fatty Acids In Northern Quahogs, Mercenaria Mercenaria, Through Decreasing Temperature, Sixto E. Portilla
All Graduate Works by Year: Dissertations, Theses, and Capstone Projects
The series of investigations described in this thesis were designed to assess the effect of diet on mortality through decreasing temperature in two genetic varieties of M. mercenaria important to the natural environment and the aquaculture industry: “wild” from natural stocks and “notata” selected for fast growth. Data from these novel investigations demonstrate a temperature specific sensitivity to each dietary component designating 20:5n-3 as homeoviscously favorable in the upper thermal range above 12°C, and 22:6n-3 as favorable in the lower. Statistical analyses of variance demonstrate distinct cumulative mortalities among the 5 dietary treatments (P < 0.05) for each genetic variety at each thermal range, upper (>12°C) and ...
Effect Of Aeration Under Pressure On Diacetyl Production In Butter Cultures, 2017 Iowa State College
Effect Of Aeration Under Pressure On Diacetyl Production In Butter Cultures, C. R. Brewer, C. H. Werkman, M. B. Michaelian, B. W. Hammer
Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)
The results presented indicate that the production of diacetyl in butter cultures and pure cultures of citric acid fermenting streptococci can be greatly increased by growing the cultures under 30 pounds or more of air pressure per square inch, provided the cultures are agitated by aeration or stirring. This increase frequently amounts to several hundred percent. In some cases the yield of acetylmethylcarbinol was increased by aeration under pressure, and in other cases it was not. Occasionally, the increase was relatively large.
Pressure without agitation was not effective in increasing the diketone content. The cultures under pressure must be agitaed ...
The 'Pseudomonas Aeruginosa' Psl Polysaccharide Is A Social But Noncheatable Trait In Biofilms, 2017 University of Dayton
The 'Pseudomonas Aeruginosa' Psl Polysaccharide Is A Social But Noncheatable Trait In Biofilms, Yasuhiko Irie, Aled E. Roberts, Kasper N. Kragh, Vernita D. Gordon, Jaime B. Hutchison, Rosalind J. Allen, Gavin Melaugh, Thomas Bjarnsholt, Stuart A. West, Stephen P. Diggle
Biology Faculty Publications
Extracellular polysaccharides are compounds secreted by microorganisms into the surrounding environment, and they are important for surface attachment and maintaining structural integrity within biofilms. The social nature of many extracellular polysaccharides remains unclear, and it has been suggested that they could function as either cooperative public goods or as traits that provide a competitive advantage. Here, we empirically tested the cooperative nature of the PSL polysaccharide, which is crucial for the formation of biofilms in Pseudomonas aeruginosa. We show that (i) PSL is not metabolically costly to produce; (ii) PSL provides populationlevel benefits in biofilms, for both growth and antibiotic ...
Reduction Of Acetylmethylcarbinol And Diacetyl To 2,3-Butylene Glycol By The Citric Acid Fermenting Streptococci Of Butter Cultures, B. W. Hammer, G. L. Stahly, C. H. Werkman, M. B. Michaelian
Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)
When acetylmethylcarbinol or diacetyl was added to a tomato bouillon culture of one of the citric acid fermenting streptococci normally present in butter cultures, there was a rapid disappearance of the added reagent and an increase in 2,3-butylene glycol. The amount of the glycol produced accounted, in a general way, for the acetylmethylcarbinol or diacetyl that disappeared. The added reagent did not usually disappear completely. In trials with acetylmethylcarbinol the change of the carbinol to the glycol was delayed when sulfuric acid was added in amounts to yield a pH of from 3.8 to 4.0.
There was ...
Symptomatic Surgically Treated Non-Neoplastic Cysts Of The Central Nervous System: A Clinicopathological Study From Pakistan, Nasir Ud Din, Huma Arshad, Zubair Ahmad, Sheema H Hasan, Mohammad Ehsan Bar
Objective: To report clinicopathologic features of symptomatic surgically removed non-neoplastic cysts of the central nervous system (CNS). Study Design: Case series. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from 2003 to 2012. Methodology: All non-neoplastic CNS cysts reported during the study period were retrieved and reviewed. Age, gender, location, histologic type and clinical features were noted. Results: A total of 124 cysts were diagnosed in the study period. These included 44 epidermoid cysts (mean age 30.5 ± 13.8 years), 35 colloid cysts (mean age 31 ± 13.2 years), 32 arachnoid cysts (mean age 24.8 ...
In-House Daily Consensus Conference: An Important Quality Control/Quality Assurance Activity--Experience At A Major Referral Center., Amna Khurshid, Zubair Ahmad, Asim Qureshi
Background:For every practicing histopathologist, improvement of diagnostic accuracy is an important objective. Personal consults are an important component of quality control (QC)/quality assurance (QA) in our Section of Histopathology. In addition, the College of American Pathologists recommends a daily in-house consensus conference, which is a prospective system by which all difficult and problematic cases are reviewed and discussed and signed out by consensus. Design: In-house consensus conference is held daily using a multi-headed microscope. This collegial session is run by the seniormost consultant in the section and is attended by all histopathology consultants and residents. The consultants and ...
Histological Pattern Of Ovarian Neoplasma., 2017 Agha Khan University
Histological Pattern Of Ovarian Neoplasma., Zubair Ahmad, Naila Kayani, Sheema H. Hasan, Suhail Muzaffar, Muhammad Shafiq Gill
Abstract Objective: To see the morphological pattern of benign and malignant ovarian neoplasms. Method: Retrospective study of all consecutive cases of ovarian neoplasms diagnosed at Aga Khan University Hospital between 1st January 1993 and 30th September 1998. Setting: The Section of Histopathology, AKUH, Karachi. Observation: Of 855 ovarian tumours 506 (59.18%) were benign and 349(40.81%) malignant. Surface epithelial - stromal tumours comprised 63.50% of all tumours. Benign cystic teratoma was the commonest benign tumour (35.17% of all benign tumours) and serous cystadenocarcinoma was the commonest malignant tumour (33.33% of all malignant tumours). Mucinous cystadenocarcinomas are ...
Frequency Of Hereditary Thrombophilia: An Akuh Experience., 2017 Aga Khan University
Frequency Of Hereditary Thrombophilia: An Akuh Experience., Safoorah Khalid, Raihan Sajid, Salman Adil, Mohammad Khurshid
Salman Naseem Adil
Abstract Objective: To determine the frequency of various causes of hereditary thrombophilia at a referral laboratory and the age and gender distribution. Methods: This is a descriptive study incorporating a retrospective analysis of requests for thrombophilia screening sent to Clinical laboratory, Aga Khan University Hospital from November 1995 to May 2002.Patients were screened for hereditary causes of thrombophilia including Protein C, Protein S, antithrombin III, Factor V Leiden and homocysteine. Frequency of each disorder; and age and sex distribution was determined. Results: All the patients suspected clinically for thrombophilia were screened. Of the 2825 patients, 70 were diagnosed to ...