WorldWideScience

Sample records for biosynthesis electronic resource

  1. ELECTRONIC HUMAN RESOURCE MANAGEMENT

    OpenAIRE

    Dr. M. Panneerselvam

    2017-01-01

    Electronic Human Resource Management is an essence the revolution of human resource functions to management and employees. These functions are typically used via intranet and web technology. This helps the organization to improve their standards where they can able to review and forward. All those documents can be viewed within a fraction of second with help of client and server links. The phenomenon of E- HRM deserves closer and more fundamental roots to HR activity. The E-HRM develops and b...

  2. Electronic Resource Management and Design

    Science.gov (United States)

    Abrams, Kimberly R.

    2015-01-01

    We have now reached a tipping point at which electronic resources comprise more than half of academic library budgets. Because of the increasing work associated with the ever-increasing number of e-resources, there is a trend to distribute work throughout the library even in the presence of an electronic resources department. In 2013, the author…

  3. Managing electronic resources a LITA guide

    CERN Document Server

    Weir, Ryan O

    2012-01-01

    Informative, useful, current, Managing Electronic Resources: A LITA Guide shows how to successfully manage time, resources, and relationships with vendors and staff to ensure personal, professional, and institutional success.

  4. Implementing CORAL: An Electronic Resource Management System

    Science.gov (United States)

    Whitfield, Sharon

    2011-01-01

    A 2010 electronic resource management survey conducted by Maria Collins of North Carolina State University and Jill E. Grogg of University of Alabama Libraries found that the top six electronic resources management priorities included workflow management, communications management, license management, statistics management, administrative…

  5. Electronic Resources Management Project Presentation 2012

    KAUST Repository

    Ramli, Rindra M.

    2012-11-05

    This presentation describes the electronic resources management project undertaken by the KAUST library. The objectives of this project is to migrate information from MS Sharepoint to Millennium ERM module. One of the advantages of this migration is to consolidate all electronic resources into a single and centralized location. This would allow for better information sharing among library staff.

  6. Electronic Resources Management System: Recommendation Report 2017

    KAUST Repository

    Ramli, Rindra M.

    2017-05-01

    This recommendation report provides an overview of the selection process for the new Electronic Resources Management System. The library has decided to move away from Innovative Interfaces Millennium ERM module. The library reviewed 3 system as potential replacements namely: Proquest 360 Resource Manager, Ex Libris Alma and Open Source CORAL ERMS. After comparing and trialling the systems, it was decided to go for Proquest 360 Resource Manager.

  7. CHALLENGES OF ELECTRONIC INFORMATION RESOURCES IN ...

    African Journals Online (AJOL)

    This paper discusses the role of policy for proper and efficient library services in the electronic era. It points out ... New approaches in acquisition, accessing, selection, preservation and choices on whether to operate digital, or combine traditional print and digital resources in the library have to be worked out and adopted.

  8. 2015 Utilization of Electronic Information Resources in Ramat

    African Journals Online (AJOL)

    electronic resources, electronic books, electronic learning, electronic journals, as well as electronic archive among others is intensely powerful and has permeated all segments and sectors of the society. Electronic information resources (EIRS) as reported by Meitz (2004), are "Library materials produced in electronic format.

  9. The calculating rating of electronic resources

    OpenAIRE

    MUMINOV BAHODIR.BOLTAYEICH

    2016-01-01

    The rating of electron resources is devoted to count by theories, directions in this work. The calculating model of rating of ER by entering and exiting directions on bases of used widely PageRank is produced for calculating the rating of web pages in Google searching system. The rating of ER is taken into account for calculating the ratings of entering direction and the calculating exiting direction is accomplished by equitable distribution of ER. And also the calculating rating ER among kin...

  10. Making sense of the electronic resource marketplace: trends in health-related electronic resources.

    Science.gov (United States)

    Blansit, B D; Connor, E

    1999-07-01

    Changes in the practice of medicine and technological developments offer librarians unprecedented opportunities to select and organize electronic resources, use the Web to deliver content throughout the organization, and improve knowledge at the point of need. The confusing array of available products, access routes, and pricing plans makes it difficult to anticipate the needs of users, identify the top resources, budget effectively, make sound collection management decisions, and organize the resources effectively and seamlessly. The electronic resource marketplace requires much vigilance, considerable patience, and continuous evaluation. There are several strategies that librarians can employ to stay ahead of the electronic resource curve, including taking advantage of free trials from publishers; marketing free trials and involving users in evaluating new products; watching and testing products marketed to the clientele; agreeing to beta test new products and services; working with aggregators or republishers; joining vendor advisory boards; benchmarking institutional resources against five to eight competitors; and forming or joining a consortium for group negotiating and purchasing. This article provides a brief snapshot of leading biomedical resources; showcases several libraries that have excelled in identifying, acquiring, and organizing electronic resources; and discusses strategies and trends of potential interest to biomedical librarians, especially those working in hospital settings.

  11. Electronic resource management systems a workflow approach

    CERN Document Server

    Anderson, Elsa K

    2014-01-01

    To get to the bottom of a successful approach to Electronic Resource Management (ERM), Anderson interviewed staff at 11 institutions about their ERM implementations. Among her conclusions, presented in this issue of Library Technology Reports, is that grasping the intricacies of your workflow-analyzing each step to reveal the gaps and problems-at the beginning is crucial to selecting and implementing an ERM. Whether the system will be used to fill a gap, aggregate critical data, or replace a tedious manual process, the best solution for your library depends on factors such as your current soft

  12. Utilization of electronic information resources in Ramat Library ...

    African Journals Online (AJOL)

    ... printer, and audio-visuals are equally available. Student have unlimited accessibility in the utilization of electronic resources, students frequently utilized electronic information resources in Ramat Library. It is recommended, among others, that registered students should utilize and access electronic information resources ...

  13. Impact of electronic resources use on academic performance of ...

    African Journals Online (AJOL)

    Results indicated that use of electronic resources had a positive impact on students' academic performance. Based on the findings of this study, it is recommended that more emphasis should be laid on the acquisition of electronic resources so as to give room for wider and multiple access to information resources in order to ...

  14. Use of Electronic Resources in a Private University in Nigeria ...

    African Journals Online (AJOL)

    The study examined awareness and constraints in the use of electronic resources by lecturers and students of Ajayi Crowther University, Oyo, Nigeria. It aimed at justifying the resources expended in the provision of electronic resources in terms of awareness, patronage and factors that may be affecting awareness and use ...

  15. The Evolution of Selection Activities for Electronic Resources.

    Science.gov (United States)

    Davis, Trisha L.

    1997-01-01

    Selection of electronic resources--CD-ROMs, dial access databases, electronic journals, and World Wide Web products--requires a more extensive set of criteria than do print resources. Discusses two factors influencing collection development of electronic products: technology options and licensing issues, and outlines how traditional selection…

  16. Electronic Resource Management System. Vernetzung von Lizenzinformationen

    Directory of Open Access Journals (Sweden)

    Michaela Selbach

    2014-12-01

    Full Text Available In den letzten zehn Jahren spielen elektronische Ressourcen im Bereich der Erwerbung eine zunehmend wichtige Rolle: Eindeutig lässt sich hier ein Wandel in den Bibliotheken (fort vom reinen Printbestand zu immer größeren E-Only-Beständen feststellen. Die stetig wachsende Menge an E-Ressourcen und deren Heterogenität stellt Bibliotheken vor die Herausforderung, die E-Ressourcen effizient zu verwalten. Nicht nur Bibliotheken, sondern auch verhandlungsführende Institutionen von Konsortial- und Allianzlizenzen benötigen ein geeignetes Instrument zur Verwaltung von Lizenzinformationen, welches den komplexen Anforderungen moderner E-Ressourcen gerecht wird. Die Deutsche Forschungsgemeinschaft (DFG unterstützt ein Projekt des Hochschulbibliothekszentrums des Landes Nordrhein-Westfalen (hbz, der Universitätsbibliothek Freiburg, der Verbundzentrale des Gemeinsamen Bibliotheksverbundes (GBV und der Universitätsbibliothek Frankfurt, in dem ein bundesweit verfügbares Electronic Ressource Managementsystem (ERMS aufgebaut werden soll. Ein solches ERMS soll auf Basis einer zentralen Knowledge Base eine einheitliche Nutzung von Daten zur Lizenzverwaltung elektronischer Ressourcen auf lokaler, regionaler und nationaler Ebene ermöglichen. Statistische Auswertungen, Rechteverwaltung für alle angeschlossenen Bibliotheken, kooperative Datenpflege sowie ein über standardisierte Schnittstellen geführter Datenaustausch stehen bei der Erarbeitung der Anforderungen ebenso im Fokus wie die Entwicklung eines Daten- und Funktionsmodells. In the last few years the importance of electronic resources in library acquisitions has increased significantly. There has been a shift from mere print holdings to both e- and print combinations and even e-only subscriptions. This shift poses a double challenge for libraries: On the one hand they have to provide their e-resource collections to library users in an appealing way, on the other hand they have to manage these

  17. Electronic resources access and usage among the postgraduates of ...

    African Journals Online (AJOL)

    Electronic resources access and usage among the postgraduates of a Nigerian University of Technology. ... by postgraduates in using e-resources include takes too much time to find, e-resources are not always accessible, lack of supporting structures (connection, downloading, printing limits) and too many resources.

  18. Utilization of electronic information resources by academic staff at ...

    African Journals Online (AJOL)

    The study investigated the utilization of Electronic Information resources by the academic staff of Makerere University in Uganda. It examined the academic staff awareness of the resources available, the types of resources provided by the Makerere University Library, the factors affecting resource utilization. The study was ...

  19. The impact of electronic information resource use on research output

    African Journals Online (AJOL)

    This paper examines the impact of the use of electronic information resources on research output in the universities in Tanzania. Research for this paper was conducted in five public universities in Tanzania with varied levels of access to electronic information resources. The selection of the sample universities was ...

  20. Using Electronic Resources to Support Problem-Based Learning

    Science.gov (United States)

    Chang, Chen-Chi; Jong, Ay; Huang, Fu-Chang

    2012-01-01

    Students acquire skills in problem solving and critical thinking through the process as well as team work on problem-based learning courses. Many courses have started to involve the online learning environment and integrate these courses with electronic resources. Teachers use electronic resources in their classes. To overcome the problem of the…

  1. impact of the use of electronic resources on research output

    African Journals Online (AJOL)

    manda

    Abstract. This paper examines the impact of the use of electronic information resources on research output in the universities in Tanzania. Research for this paper was conducted in five public universities in Tanzania with varied levels of access to electronic information resources. The selection of the sample universities was ...

  2. The Role of the Acquisitions Librarian in Electronic Resources Management

    Science.gov (United States)

    Pomerantz, Sarah B.

    2010-01-01

    With the ongoing shift to electronic formats for library resources, acquisitions librarians, like the rest of the profession, must adapt to the rapidly changing landscape of electronic resources by keeping up with trends and mastering new skills related to digital publishing, technology, and licensing. The author sought to know what roles…

  3. Use of electronic resources by undergraduates in two selected ...

    African Journals Online (AJOL)

    The purpose of this study is to know the extent of use of electronic resources and identify the type of electronic resources used by undergraduates in universities in Nigeria. Questionnaire was used for data collection. The study population includes all undergraduate students in the faculty of engineering in Niger Delta ...

  4. Electronic resources preferred by pediatric hospitalists for clinical care.

    Science.gov (United States)

    Beck, Jimmy B; Tieder, Joel S

    2015-10-01

    There is little research on pediatric hospitalists' use of evidence-based resources. The aim of this study was to determine the electronic resources that pediatric hospitalists prefer. Using a web-based survey, the authors determined hospitalists' preferred electronic resources, as well as their attitudes toward lifelong learning, practice, and experience characteristics. One hundred sixteen hospitalists completed the survey. The most preferred resource for general information, patient handouts, and treatment was UpToDate. Online search engines were ranked second for general information and patient handouts. Pediatric hospitalists tend to utilize less rigorous electronic resources such as UpToDate and Google. These results can set a platform for discussing the quality of resources that pediatric hospitalists use.

  5. Library training to promote electronic resource usage

    DEFF Research Database (Denmark)

    Frandsen, Tove Faber; Tibyampansha, Dativa; Ibrahim, Glory

    2017-01-01

    of implementing training programmes to encourage the use of the e-library. Findings: Training sessions increase the usage of library e-resources significantly; however, the effect seems to be short-lived and training sessions alone may not increase the overall long-term usage. Originality/value: The present paper...

  6. Integrating Electronic Resources into the Library Catalog: A Collaborative Approach.

    Science.gov (United States)

    Herrera, Gail; Aldana, Lynda

    2001-01-01

    Describes a project at the University of Mississippi Libraries to catalog purchased electronic resources so that access to these resources is available only via the Web-based library catalog. Discusses collaboration between cataloging and systems personnel; and describes the MARC catalog record field that contains the information needed to locate…

  7. Utilisation of Electronic Information Resources By Lecturers in ...

    African Journals Online (AJOL)

    This study assesses the use of information resources, specifically, electronic databases by lecturers/teachers in Universities and Colleges of Education in South Western Nigeria. Information resources are central to teachers' education. It provides lecturers/teachers access to information that enhances research and ...

  8. Preservation and conservation of electronic information resources of ...

    African Journals Online (AJOL)

    The major holdings of the broadcast libraries of the Nigerian Television Authority (NTA) are electronic information resources; therefore, providing safe places for general management of these resources have aroused interest in the industry in Nigeria for sometimes. The need to study the preservation and conservation of ...

  9. Using XML Technologies to Organize Electronic Reference Resources

    OpenAIRE

    Huser, Vojtech; Del Fiol, Guilherme; Rocha, Roberto A.

    2005-01-01

    Provision of access to reference electronic resources to clinicians is becoming increasingly important. We have created a framework for librarians to manage access to these resources at an enterprise level, rather than at the individual hospital libraries. We describe initial project requirements, implementation details, and some preliminary results.

  10. Euler European Libraries and Electronic Resources in Mathematical Sciences

    CERN Document Server

    The Euler Project. Karlsruhe

    The European Libraries and Electronic Resources (EULER) Project in Mathematical Sciences provides the EulerService site for searching out "mathematical resources such as books, pre-prints, web-pages, abstracts, proceedings, serials, technical reports preprints) and NetLab (for Internet resources), this outstanding engine is capable of simple, full, and refined searches. It also offers a browse option, which responds to entries in the author, keyword, and title fields. Further information about the Project is provided at the EULER homepage.

  11. Building an electronic resource collection a practical guide

    CERN Document Server

    Lee, Stuart D

    2004-01-01

    This practical book guides information professionals step-by-step through building and managing an electronic resource collection. It outlines the range of electronic products currently available in abstracting and indexing, bibliographic, and other services and then describes how to effectively select, evaluate and purchase them.

  12. Organizational matters of competition in electronic educational resources

    Directory of Open Access Journals (Sweden)

    Ирина Карловна Войтович

    2015-12-01

    Full Text Available The article examines the experience of the Udmurt State University in conducting competitions of educational publications and electronic resources. The purpose of such competitions is to provide methodological support to educational process. The main focus is on competition of electronic educational resources. The technology of such contests is discussed through detailed analysis of the main stages of the contest. It is noted that the main task of the preparatory stage of the competition is related to the development of regulations on competition and the definition of criteria for selection of the submitted works. The paper also proposes a system of evaluation criteria of electronic educational resources developed by members of the contest organizing committee and jury members. The article emphasizes the importance of not only the preparatory stages of the competition, but also measures for its completion, aimed at training teachers create quality e-learning resources.

  13. USE OF VIDEO IN MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES

    Directory of Open Access Journals (Sweden)

    Svitlana Denisenko

    2015-10-01

    Full Text Available The widespread introduction of electronic educational resources in the educational process requires the development of a scientific basis for all aspects related to their creation and use. These modern means are designed not just to convey to learners the required course material, but also to create conditions for its most effective study. This is possible in conditions of reasonable approach to the presentation of educational material on the screen. The article is devoted to consideration of the problem of presenting educational material in electronic educational resources. Visuals are powerful didactic tool that enhances the perception and understanding of educational information. Particular attention is paid to the use of such a powerful medium like video. Investigated the role and importance of video in the learning process, their educational opportunities and benefits. Shows types of video and their use in electronic educational resources. Grounded requirements for training videos. The recommendations are given on the use of video in combination with other media in electronic educational resources. Adduced the example a real electronic multimedia educational resource and shows the possibility of using video.

  14. Why and How to Measure the Use of Electronic Resources

    Directory of Open Access Journals (Sweden)

    Jean Bernon

    2008-11-01

    Full Text Available A complete overview of library activity implies a complete and reliable measurement of the use of both electronic resources and printed materials. This measurement is based on three sets of definitions: document types, use types and user types. There is a common model of definitions for printed materials, but a lot of questions and technical issues remain for electronic resources. In 2006 a French national working group studied these questions. It relied on the COUNTER standard, but found it insufficient and pointed out the need for local tools such as web markers and deep analysis of proxy logs. Within the French national consortium COUPERIN, a new working group is testing ERMS, SUSHI standards, Shibboleth authentication, along with COUNTER standards, to improve the counting of the electronic resources use. At this stage this counting is insufficient and its improvement will be a European challenge for the future.

  15. The Study of Analytical Model of Library Electronic Resources Usage-A Case of Medical Electronic Resources

    Directory of Open Access Journals (Sweden)

    Chung-Yen Yu

    2014-10-01

    Full Text Available With the advents of internet, the importance of electronic resources is growing. Due to the increasing expensiveness of electronic resources, university libraries normally received budgets from parent institutions annually. They necessarily applied effective and systematic methods for decision making in electronic resources purchase or re-subscription. However, there are some difficulties in practices: First of all, libraries are unable to receive user records; second, the COUNTER statistics does not include details about users and their affiliation. As a result, one cannot conduct advanced user analysis based on the usage of users, institutions, and departments. To overcome the difficulties, this study presents a feasible model to analyze electronic resource usage effectively and flexibly. We set up a proxy server to collect actual usage raw data. By analyzing items in internet browsing records, associated with original library automatic system, this study aims at exploring how to use effective ways to analyze big data of website log data. We also propose the process of how original data to be transformed, cleared, integrated, and demonstrated. This study adopted a medical university library and its subscription of medical electronic resources as a case. Our data analysis includes (1 year of subscription,(2 title of journal, (3 affiliation, (4 subjects, and (5 specific journal requirements, etc. The findings of the study are contributed to obtain further understanding in policy making and user behavior analysis. The integrated data provides multiple applications in informatics research, information behavior, bibliomining, presenting diverse views and extended issues for further discussion.

  16. Access to electronic resources by visually impaired people

    Directory of Open Access Journals (Sweden)

    Jenny Craven

    2003-01-01

    Full Text Available Research into access to electronic resources by visually impaired people undertaken by the Centre for Research in Library and Information Management has not only explored the accessibility of websites and levels of awareness in providing websites that adhere to design for all principles, but has sought to enhance understanding of information seeking behaviour of blind and visually impaired people when using digital resources.

  17. Practical guide to electronic resources in the humanities

    CERN Document Server

    Dubnjakovic, Ana

    2010-01-01

    From full-text article databases to digitized collections of primary source materials, newly emerging electronic resources have radically impacted how research in the humanities is conducted and discovered. This book, covering high-quality, up-to-date electronic resources for the humanities, is an easy-to-use annotated guide for the librarian, student, and scholar alike. It covers online databases, indexes, archives, and many other critical tools in key humanities disciplines including philosophy, religion, languages and literature, and performing and visual arts. Succinct overviews of key eme

  18. Electronic Commerce Resource Centers. An Industry--University Partnership.

    Science.gov (United States)

    Gulledge, Thomas R.; Sommer, Rainer; Tarimcilar, M. Murat

    1999-01-01

    Electronic Commerce Resource Centers focus on transferring emerging technologies to small businesses through university/industry partnerships. Successful implementation hinges on a strategic operating plan, creation of measurable value for customers, investment in customer-targeted training, and measurement of performance outputs. (SK)

  19. Printed And Electronic Resources Utilization By Agricultural Science ...

    African Journals Online (AJOL)

    This paper examines the use of printed and electronic resources by agricultural science students in three Nigerian universities. A two-part questionnaire was designed to elicit necessary information from the respondents selected for the study. One thousand three hundred (1300) respondents from faculties of Agriculture in ...

  20. Electronic information resource sharing among university libraries in ...

    African Journals Online (AJOL)

    The study explored the state of electronic information resource sharing among university libraries in Southern part of Nigeria, highlighting the prospects and the challenges. The study was an empirical research which adopted the descriptive survey as the design. The questionnaire was used to collect data from the ...

  1. Page 170 Use of Electronic Resources by Undergraduates in Two ...

    African Journals Online (AJOL)

    undergraduate students use electronic resources such as NUC virtual library, HINARI, E- journals, CD-ROMs, AGORA, and ... to finance and geographical location. Furthermore, in developed countries like United Kingdom, students get access to .... databases, web sources and audio-video tapes. Furthermore, studies also ...

  2. Modern ICT Tools: Online Electronic Resources Sharing Using Web ...

    African Journals Online (AJOL)

    Modern ICT Tools: Online Electronic Resources Sharing Using Web 2.0 and Its Implications For Library And Information Practice In Nigeria. ... The PDF file you selected should load here if your Web browser has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader). If you would like more ...

  3. Users satisfaction with electronic information resources and services ...

    African Journals Online (AJOL)

    Users satisfaction with electronic information resources and services in A.B.U & UNIBEN MTN Net Libraries. ... Lastly, management of the MTN Net Libraries should conduct user studies annually in order to have feedback from users on how well the library is meeting their information needs. The results of the survey should ...

  4. ANALYTICAL REVIEW OF ELECTRONIC RESOURCES FOR THE STUDY OF LATIN

    Directory of Open Access Journals (Sweden)

    Olena Yu. Balalaieva

    2014-04-01

    Full Text Available The article investigates the current state of development of e-learning content in the Latin language. It is noted that the introduction of ICT in the educational space has expanded the possibility of studying Latin, opened access to digital libraries resources, made it possible to use scientific and educational potential and teaching Latin best practices of world's leading universities. A review of foreign and Ukrainian information resources and electronic editions for the study of Latin is given. Much attention was paid to the didactic potential of local and online multimedia courses of Latin, electronic textbooks, workbooks of interactive tests and exercises, various dictionaries and software translators, databases and digital libraries. Based on analysis of the world market of educational services and products the main trends in the development of information resources and electronic books are examined. It was found that multimedia courses with interactive exercises or workbooks with interactive tests, online dictionaries and translators are the most widely represented and demanded. The noticeable lagging of Ukrainian education and computer linguistics in quantitative and qualitative measures in this industry is established. The obvious drawback of existing Ukrainian resources and electronic editions for the study of Latin is their noninteractive nature. The prospects of e-learning content in Latin in Ukraine are outlined.

  5. Gender Analysis Of Electronic Information Resource Use: The Case ...

    African Journals Online (AJOL)

    This article is based on an empirical study that examined the association between gender and the use of electronic information resources among postgraduate students at the University of Dar es salaam, Tanzania. The study was conducted in December 2005 and integrated both qualitative and quantitative research ...

  6. Use of electronic information resources among the undergraduate ...

    African Journals Online (AJOL)

    The study aimed at finding out the use of electronic information resources among undergraduate students in the Federal University of Technology, Akure. The study is based on descriptive survey design method and the population consists of 16,962 undergraduate students across different schools at the Federal University ...

  7. Adoption and use of electronic information resources by medical ...

    African Journals Online (AJOL)

    This study investigated the adoption and use of electronic information resources by medical science students of the University of Benin. The descriptive survey research design was adopted for the study and 390 students provided the data. Data collected were analysed with descriptive Statistics(Simple percentage and ...

  8. Student Satisfaction with Electronic Library Resources at Wayne State University

    Science.gov (United States)

    Holley, Robert P.; Powell, Ronald R.

    2004-01-01

    This paper reports the results of a survey of student satisfaction with electronic library resources other than the online catalog at Wayne State University. Undertaken in Fall Term 2000 as a class project for a marketing course, a student team designed, administered, and analyzed a survey of a random sample of students. Almost 40% of the…

  9. Technical Communicator: A New Model for the Electronic Resources Librarian?

    Science.gov (United States)

    Hulseberg, Anna

    2016-01-01

    This article explores whether technical communicator is a useful model for electronic resources (ER) librarians. The fields of ER librarianship and technical communication (TC) originated and continue to develop in relation to evolving technologies. A review of the literature reveals four common themes for ER librarianship and TC. While the…

  10. Access to electronic information resources by students of federal ...

    African Journals Online (AJOL)

    The paper discusses access to electronic information resources by students of Federal Colleges of Education in Eha-Amufu and Umunze. Descriptive survey design was used to investigate sample of 526 students. Sampling technique used was a Multi sampling technique. Data for the study were generated using ...

  11. Development of transcriptomic resources for interrogating the biosynthesis of monoterpene indole alkaloids in medicinal plant species.

    Directory of Open Access Journals (Sweden)

    Elsa Góngora-Castillo

    Full Text Available The natural diversity of plant metabolism has long been a source for human medicines. One group of plant-derived compounds, the monoterpene indole alkaloids (MIAs, includes well-documented therapeutic agents used in the treatment of cancer (vinblastine, vincristine, camptothecin, hypertension (reserpine, ajmalicine, malaria (quinine, and as analgesics (7-hydroxymitragynine. Our understanding of the biochemical pathways that synthesize these commercially relevant compounds is incomplete due in part to a lack of molecular, genetic, and genomic resources for the identification of the genes involved in these specialized metabolic pathways. To address these limitations, we generated large-scale transcriptome sequence and expression profiles for three species of Asterids that produce medicinally important MIAs: Camptotheca acuminata, Catharanthus roseus, and Rauvolfia serpentina. Using next generation sequencing technology, we sampled the transcriptomes of these species across a diverse set of developmental tissues, and in the case of C. roseus, in cultured cells and roots following elicitor treatment. Through an iterative assembly process, we generated robust transcriptome assemblies for all three species with a substantial number of the assembled transcripts being full or near-full length. The majority of transcripts had a related sequence in either UniRef100, the Arabidopsis thaliana predicted proteome, or the Pfam protein domain database; however, we also identified transcripts that lacked similarity with entries in either database and thereby lack a known function. Representation of known genes within the MIA biosynthetic pathway was robust. As a diverse set of tissues and treatments were surveyed, expression abundances of transcripts in the three species could be estimated to reveal transcripts associated with development and response to elicitor treatment. Together, these transcriptomes and expression abundance matrices provide a rich resource

  12. Evaluating the appropriateness of electronic information resources for learning.

    Science.gov (United States)

    Saparova, Dinara; Nolan, Nathanial S

    2016-01-01

    Current US medical students have begun to rely on electronic information repositories-such as UpToDate, AccessMedicine, and Wikipedia-for their pre-clerkship medical education. However, it is unclear whether these resources are appropriate for this level of learning due to factors involving information quality, level of evidence, and the requisite knowledgebase. This study evaluated appropriateness of electronic information resources from a novel perspective: amount of mental effort learners invest in interactions with these resources and effects of the experienced mental effort on learning. Eighteen first-year medical students read about three unstudied diseases in the above-mentioned resources (a total of fifty-four observations). Their eye movement characteristics (i.e., fixation duration, fixation count, visit duration, and task-evoked pupillary response) were recorded and used as psychophysiological indicators of the experienced mental effort. Post reading, students' learning was assessed with multiple-choice tests. Eye metrics and test results constituted quantitative data analyzed according to the repeated Latin square design. Students' perceptions of interacting with the information resources were also collected. Participants' feedback during semi-structured interviews constituted qualitative data and was reviewed, transcribed, and open coded for emergent themes. Compared to AccessMedicine and Wikipedia, UpToDate was associated with significantly higher values of eye metrics, suggesting learners experienced higher mental effort. No statistically significant difference between the amount of mental effort and learning outcomes was found. More so, descriptive statistical analysis of the knowledge test scores suggested similar levels of learning regardless of the information resource used. Judging by the learning outcomes, all three information resources were found appropriate for learning. UpToDate, however, when used alone, may be less appropriate for first

  13. Ascorbate Biosynthesis in Mitochondria Is Linked to the Electron Transport Chain between Complexes III and IV1

    Science.gov (United States)

    Bartoli, Carlos G.; Pastori, Gabriela M.; Foyer, Christine H.

    2000-01-01

    Ascorbic acid is synthesized from galactono-γ-lactone (GL) in plant tissues. An improved extraction procedure involving ammonium sulfate precipitation of membrane proteins from crude leaf homogenates yielded a simple, quick method for determining tissue activities of galactono-γ-lactone dehydrogenase (GLDH). Total foliar ascorbate and GLDH activity decreased with leaf age. Subcellular fractionation experiments using marker enzymes demonstrated that 80% of the total GLDH activity was located on the inner mitochondrial membrane, and 20% in the microsomal fraction. Specific antibody raised against potato (Solanum tuberosum L.) tuber GLDH recognized a 56-kD polypeptide in extracts from the mitochondrial membranes but failed to detect the equivalent polypeptide in microsomes. We demonstrate that isolated intact mitochondria synthesize ascorbate in the presence of GL. GL stimulated mitochondrial electron transport rates. The respiration inhibitor antimycin A stimulated ascorbate biosynthesis, while cyanide inhibited both respiration and ascorbate production. GL-dependent oxygen uptake was observed in isolated intact mitochondria. This evidence suggests that GLDH delivers electrons to the mitochondrial electron transport chain between complexes III and IV. PMID:10806250

  14. TO QUESTION OF QUALITY EXAMINATION OF ELECTRONIC EDUCATIONAL RESOURCES

    OpenAIRE

    Svitlana G. Lytvynova

    2013-01-01

    The article deals with the scientific and methodological approaches to the examination of quality of electronic educational resources (EER) for secondary schools. It was defined conceptual apparatus, described the object of examination, clarified certain aspects of the functions of examination, determined the basic tasks of expertise, summarized the principles of expertise (scientific, personalization, active involvement in the learning process), described the requirements to the participants...

  15. Analysis of empty responses from electronic resources in infobutton managers.

    Science.gov (United States)

    Long, Jie; Hulse, Nathan C; Tao, Cui

    2015-01-01

    Infobuttons provide context-aware educational materials to both providers and patients and are becoming an important element in modern electronic health records (EHR) and patient health records (PHR). However, the content from different electronic resources (e-resource) as responses from infobutton manager has not been fully analyzed and evaluated. In this paper, we propose a method for automatically analyzing responses from infobutton manager. A tool is implemented to retrieve and analyze responses from infobutton manager. To test the tool, we extracted and sampled common and uncommon concepts from EHR usage data in Intermountain Healthcare's enterprise data warehouse. From the output of the tool, we evaluate infobutton performance by multiple categories, including against the most and less common used concepts, grouped by different modules in patient portal, by different e-resources, and by type of access (standardized Health Level Seven (HL7) vs not). Based on the results of our evaluation, we provide suggestions for further enhancements of infobuttons to the current implementation, including suggesting accessing priorities of e-resources and encouraging the use of the HL7 standard.

  16. Evaluating increased resource use in fibromyalgia using electronic health records

    Directory of Open Access Journals (Sweden)

    Margolis JM

    2016-11-01

    Full Text Available Jay M Margolis,1 Elizabeth T Masters,2 Joseph C Cappelleri,3 David M Smith,1 Steven Faulkner4 1Truven Health Analytics, Life Sciences, Outcomes Research, Bethesda, MD, 2Pfizer Inc, Outcomes & Evidence, New York, NY, 3Pfizer Inc, Statistics, Groton, CT, 4Pfizer Inc, North American Medical Affairs, Medical Outcomes Specialists, St Louis, MO, USA Objective: The management of fibromyalgia (FM, a chronic musculoskeletal disease, remains challenging, and patients with FM are often characterized by high health care resource utilization. This study sought to explore potential drivers of all-cause health care resource utilization and other factors associated with high resource use, using a large electronic health records (EHR database to explore data from patients diagnosed with FM. Methods: This was a retrospective analysis of de-identified EHR data from the Humedica database. Adults (≥18 years with FM were identified based on ≥2 International Classification of Diseases, Ninth Revision codes for FM (729.1 ≥30 days apart between January 1, 2008 and December 31, 2012 and were required to have evidence of ≥12 months continuous care pre- and post-index; first FM diagnosis was the index event; 12-month pre- and post-index reporting periods. Multivariable analysis evaluated relationships between variables and resource utilization. Results: Patients were predominantly female (81.4%, Caucasian (87.7%, with a mean (standard deviation age of 54.4 (14.8 years. The highest health care resource utilization was observed for the categories of “medication orders” and “physician office visits,” with 12-month post-index means of 21.2 (21.5 drug orders/patient and 15.1 (18.1 office visits/patient; the latter accounted for 73.3% of all health care visits. Opioids were the most common prescription medication, 44.3% of all patients. The chance of high resource use was significantly increased (P<0.001 26% among African-Americans vs Caucasians and for patients

  17. End-of-life resource recovery from emerging electronic products

    DEFF Research Database (Denmark)

    Parajuly, Keshav; Habib, Komal; Cimpan, Ciprian

    2016-01-01

    Integrating product design with appropriate end-of-life (EoL) processing is widely recognized to have huge potentials in improving resource recovery from electronic products. In this study, we investigate both the product characteristics and EoL processing of robotic vacuum cleaner (RVC), as a case......-case scenario, only 47% of the total materials in RVCs are ultimately recycled. While this low material recovery is mainly due to the lower plastic recycling rate, other market realities and the complex material flows in the recycling chain also contribute to it. The study provides a robust methodological...... approach for assessing the EoL performance based on the knowledge of a product and its complex recycling chain. The lessons learned can be used to support both the design and EoL processing of products with similar features, which carry a high potential for resource recovery, especially at the initial...

  18. Analysis of Human Resources Management Strategy in China Electronic Commerce Enterprises

    Science.gov (United States)

    Shao, Fang

    The paper discussed electronic-commerce's influence on enterprise human resources management, proposed and proved the human resources management strategy which electronic commerce enterprise should adopt from recruitment strategy to training strategy, keeping talent strategy and other ways.

  19. A multienzyme complex channels substrates and electrons through acetyl-CoA and methane biosynthesis pathways in Methanosarcina.

    Directory of Open Access Journals (Sweden)

    Dillon J Lieber

    Full Text Available Multienzyme complexes catalyze important metabolic reactions in many organisms, but little is known about the complexes involved in biological methane production (methanogenesis. A crosslinking-mass spectrometry (XL-MS strategy was employed to identify proteins associated with coenzyme M-coenzyme B heterodisulfide reductase (Hdr, an essential enzyme in all methane-producing archaea (methanogens. In Methanosarcina acetivorans, Hdr forms a multienzyme complex with acetyl-CoA decarbonylase synthase (ACDS, and F420-dependent methylene-H4MPT reductase (Mer. ACDS is essential for production of acetyl-CoA during growth on methanol, or for methanogenesis from acetate, whereas Mer is essential for methanogenesis from all substrates. Existence of a Hdr:ACDS:Mer complex is consistent with growth phenotypes of ACDS and Mer mutant strains in which the complex samples the redox status of electron carriers and directs carbon flux to acetyl-CoA or methanogenesis. We propose the Hdr:ACDS:Mer complex comprises a special class of multienzyme redox complex which functions as a "biological router" that physically links methanogenesis and acetyl-CoA biosynthesis pathways.

  20. Effects of Electronic Information Resources Skills Training for Lecturers on Pedagogical Practices and Research Productivity

    Science.gov (United States)

    Bhukuvhani, Crispen; Chiparausha, Blessing; Zuvalinyenga, Dorcas

    2012-01-01

    Lecturers use various electronic resources at different frequencies. The university library's information literacy skills workshops and seminars are the main sources of knowledge of accessing electronic resources. The use of electronic resources can be said to have positively affected lecturers' pedagogical practices and their work in general. The…

  1. Electronic Document Management: A Human Resource Management Case Study

    Directory of Open Access Journals (Sweden)

    Thomas Groenewald

    2004-11-01

    Full Text Available This case study serve as exemplar regarding what can go wrong with the implementation of an electronic document management system. Knowledge agility and knowledge as capital, is outlined against the backdrop of the information society and knowledge economy. The importance of electronic document management and control is sketched thereafter. The literature review is concluded with the impact of human resource management on knowledge agility, which includes references to the learning organisation and complexity theory. The intervention methodology, comprising three phases, follows next. The results of the three phases are presented thereafter. Partial success has been achieved with improving the human efficacy of electronic document management, however the client opted to discontinue the system in use. Opsomming Die gevalle studie dien as voorbeeld van wat kan verkeerd loop met die implementering van ’n elektroniese dokumentbestuur sisteem. Teen die agtergrond van die inligtingsgemeenskap en kennishuishouding word kennissoepelheid en kennis as kapitaal bespreek. Die literatuurstudie word afgesluit met die inpak van menslikehulpbronbestuur op kennissoepelheid, wat ook die verwysings na die leerorganisasie en kompleksietydsteorie insluit. Die metodologie van die intervensie, wat uit drie fases bestaan, volg daarna. Die resultate van die drie fases word vervolgens aangebied. Slegs gedeelte welslae is behaal met die verbetering van die menslike doeltreffendheid ten opsigte van elektroniese dokumentbestuur. Die klient besluit egter om nie voort te gaan om die huidige sisteem te gebruik nie.

  2. The TriForC database: a comprehensive up-to-date resource of plant triterpene biosynthesis.

    Science.gov (United States)

    Miettinen, Karel; Iñigo, Sabrina; Kreft, Lukasz; Pollier, Jacob; De Bo, Christof; Botzki, Alexander; Coppens, Frederik; Bak, Søren; Goossens, Alain

    2018-01-04

    Triterpenes constitute a large and important class of plant natural products with diverse structures and functions. Their biological roles range from membrane structural components over plant hormones to specialized plant defence compounds. Furthermore, triterpenes have great potential for a variety of commercial applications such as vaccine adjuvants, anti-cancer drugs, food supplements and agronomic agents. Their biosynthesis is carried out through complicated, branched pathways by multiple enzyme types that include oxidosqualene cyclases, cytochrome P450s, and UDP-glycosyltransferases. Given that the number of characterized triterpene biosynthesis enzymes has been growing fast recently, the need for a database specifically focusing on triterpene enzymology became eminent. Here, we present the TriForC database (http://bioinformatics.psb.ugent.be/triforc/), encompassing a comprehensive catalogue of triterpene biosynthesis enzymes. This highly interlinked database serves as a user-friendly access point to versatile data sets of enzyme and compound features, enabling the scanning of a complete catalogue of experimentally validated triterpene enzymes, their substrates and products, as well as the pathways they constitute in various plant species. The database can be accessed by direct browsing or through convenient search tools including keyword, BLAST, plant species and substructure options. This database will facilitate gene mining and creating genetic toolboxes for triterpene synthetic biology. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  3. TO QUESTION OF QUALITY EXAMINATION OF ELECTRONIC EDUCATIONAL RESOURCES

    Directory of Open Access Journals (Sweden)

    Svitlana G. Lytvynova

    2013-04-01

    Full Text Available The article deals with the scientific and methodological approaches to the examination of quality of electronic educational resources (EER for secondary schools. It was defined conceptual apparatus, described the object of examination, clarified certain aspects of the functions of examination, determined the basic tasks of expertise, summarized the principles of expertise (scientific, personalization, active involvement in the learning process, described the requirements to the participants of EER expertise, grounded EER accordance to didactic and methodological requirements, described an algorithm of preparation for  the examination object to determine compliance with the requirements of didactic. It is established that the assessment is aimed to the receipt from the experts of corresponding data and acceptance on their basis of competent decisions about expedience of the use in general educational establishments.

  4. NirN Protein from Pseudomonas aeruginosa is a Novel Electron-bifurcating Dehydrogenase Catalyzing the Last Step of Heme d1 Biosynthesis*

    Science.gov (United States)

    Adamczack, Julia; Hoffmann, Martin; Papke, Ulrich; Haufschildt, Kristin; Nicke, Tristan; Bröring, Martin; Sezer, Murat; Weimar, Rebecca; Kuhlmann, Uwe; Hildebrandt, Peter; Layer, Gunhild

    2014-01-01

    Heme d1 plays an important role in denitrification as the essential cofactor of the cytochrome cd1 nitrite reductase NirS. At present, the biosynthesis of heme d1 is only partially understood. The last step of heme d1 biosynthesis requires a so far unknown enzyme that catalyzes the introduction of a double bond into one of the propionate side chains of the tetrapyrrole yielding the corresponding acrylate side chain. In this study, we show that a Pseudomonas aeruginosa PAO1 strain lacking the NirN protein does not produce heme d1. Instead, the NirS purified from this strain contains the heme d1 precursor dihydro-heme d1 lacking the acrylic double bond, as indicated by UV-visible absorption spectroscopy and resonance Raman spectroscopy. Furthermore, the dihydro-heme d1 was extracted from purified NirS and characterized by UV-visible absorption spectroscopy and finally identified by high-resolution electrospray ionization mass spectrometry. Moreover, we show that purified NirN from P. aeruginosa binds the dihydro-heme d1 and catalyzes the introduction of the acrylic double bond in vitro. Strikingly, NirN uses an electron bifurcation mechanism for the two-electron oxidation reaction, during which one electron ends up on its heme c cofactor and the second electron reduces the substrate/product from the ferric to the ferrous state. On the basis of our results, we propose novel roles for the proteins NirN and NirF during the biosynthesis of heme d1. PMID:25204657

  5. Electronic Safety Resource Tools -- Supporting Hydrogen and Fuel Cell Commercialization

    Energy Technology Data Exchange (ETDEWEB)

    Barilo, Nick F.

    2014-09-29

    The Pacific Northwest National Laboratory (PNNL) Hydrogen Safety Program conducted a planning session in Los Angeles, CA on April 1, 2014 to consider what electronic safety tools would benefit the next phase of hydrogen and fuel cell commercialization. A diverse, 20-person team led by an experienced facilitator considered the question as it applied to the eight most relevant user groups. The results and subsequent evaluation activities revealed several possible resource tools that could greatly benefit users. The tool identified as having the greatest potential for impact is a hydrogen safety portal, which can be the central location for integrating and disseminating safety information (including most of the tools identified in this report). Such a tool can provide credible and reliable information from a trustworthy source. Other impactful tools identified include a codes and standards wizard to guide users through a series of questions relating to application and specific features of the requirements; a scenario-based virtual reality training for first responders; peer networking tools to bring users from focused groups together to discuss and collaborate on hydrogen safety issues; and a focused tool for training inspectors. Table ES.1 provides results of the planning session, including proposed new tools and changes to existing tools.

  6. Controlling user access to electronic resources without password

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Fred Hewitt

    2015-06-16

    Described herein are devices and techniques for remotely controlling user access to a restricted computer resource. The process includes pre-determining an association of the restricted computer resource and computer-resource-proximal environmental information. Indicia of user-proximal environmental information are received from a user requesting access to the restricted computer resource. Received indicia of user-proximal environmental information are compared to associated computer-resource-proximal environmental information. User access to the restricted computer resource is selectively granted responsive to a favorable comparison in which the user-proximal environmental information is sufficiently similar to the computer-resource proximal environmental information. In at least some embodiments, the process further includes comparing user-supplied biometric measure and comparing it with a predetermined association of at least one biometric measure of an authorized user. Access to the restricted computer resource is granted in response to a favorable comparison.

  7. Resources

    Science.gov (United States)

    ... Colon cancer - resources Cystic fibrosis - resources Depression - resources Diabetes - resources Digestive disease - resources Drug abuse - resources Eating disorders - resources Elder care - resources Epilepsy - resources Family ...

  8. The Internet School of Medicine: use of electronic resources by medical trainees and the reliability of those resources.

    Science.gov (United States)

    Egle, Jonathan P; Smeenge, David M; Kassem, Kamal M; Mittal, Vijay K

    2015-01-01

    Electronic sources of medical information are plentiful, and numerous studies have demonstrated the use of the Internet by patients and the variable reliability of these sources. Studies have investigated neither the use of web-based resources by residents, nor the reliability of the information available on these websites. A web-based survey was distributed to surgical residents in Michigan and third- and fourth-year medical students at an American allopathic and osteopathic medical school and a Caribbean allopathic school regarding their preferred sources of medical information in various situations. A set of 254 queries simulating those faced by medical trainees on rounds, on a written examination, or during patient care was developed. The top 5 electronic resources cited by the trainees were evaluated for their ability to answer these questions accurately, using standard textbooks as the point of reference. The respondents reported a wide variety of overall preferred resources. Most of the 73 responding medical trainees favored textbooks or board review books for prolonged studying, but electronic resources are frequently used for quick studying, clinical decision-making questions, and medication queries. The most commonly used electronic resources were UpToDate, Google, Medscape, Wikipedia, and Epocrates. UpToDate and Epocrates had the highest percentage of correct answers (47%) and Wikipedia had the lowest (26%). Epocrates also had the highest percentage of wrong answers (30%), whereas Google had the lowest percentage (18%). All resources had a significant number of questions that they were unable to answer. Though hardcopy books have not been completely replaced by electronic resources, more than half of medical students and nearly half of residents prefer web-based sources of information. For quick questions and studying, both groups prefer Internet sources. However, the most commonly used electronic resources fail to answer clinical queries more than half

  9. Developing Humanities Collections in the Digital Age: Exploring Humanities Faculty Engagement with Electronic and Print Resources

    Science.gov (United States)

    Kachaluba, Sarah Buck; Brady, Jessica Evans; Critten, Jessica

    2014-01-01

    This article is based on quantitative and qualitative research examining humanities scholars' understandings of the advantages and disadvantages of print versus electronic information resources. It explores how humanities' faculty members at Florida State University (FSU) use print and electronic resources, as well as how they perceive these…

  10. Checklist Manifesto for Electronic Resources: Getting Ready for the Fiscal Year and Beyond

    Science.gov (United States)

    England, Lenore; Fu, Li; Miller, Stephen

    2011-01-01

    Organization of electronic resources workflow is critical in the increasingly complicated and complex world of library management. A simple organizational tool that can be readily applied to electronic resources management (ERM) is the use of checklists. Based on the principles discussed in The Checklist Manifesto: How to Get Things Right, the…

  11. Electronic resource management practical perspectives in a new technical services model

    CERN Document Server

    Elguindi, Anne

    2012-01-01

    A significant shift is taking place in libraries, with the purchase of e-resources accounting for the bulk of materials spending. Electronic Resource Management makes the case that technical services workflows need to make a corresponding shift toward e-centric models and highlights the increasing variety of e-formats that are forcing new developments in the field.Six chapters cover key topics, including: technical services models, both past and emerging; staffing and workflow in electronic resource management; implementation and transformation of electronic resource management systems; the ro

  12. Use of Internet and Electronic Resources amongst Postgraduate ...

    African Journals Online (AJOL)

    Findings indicate that the study group has regular access to the internet , and preferred using free online resources from Google and Wikipedia to institutionally subscribed academic online resources in databases such as HINARI, EBSCO Host, Questia , JSTOR and High Beam.This shows that technology alone cannot help ...

  13. Strategic Planning for Electronic Resources Management: A Case Study at Gustavus Adolphus College

    Science.gov (United States)

    Hulseberg, Anna; Monson, Sarah

    2009-01-01

    Electronic resources, the tools we use to manage them, and the needs and expectations of our users are constantly evolving; at the same time, the roles, responsibilities, and workflow of the library staff who manage e-resources are also in flux. Recognizing a need to be more intentional and proactive about how we manage e-resources, the…

  14. Preservation of and Permanent Access to Electronic Information Resources

    National Research Council Canada - National Science Library

    Hodge, Gail

    2004-01-01

    The rapid growth in the creation and dissemination of electronic information has emphasized the digital environment's speed and ease of dissemination with little regard for its long-term preservation and access...

  15. Controlling user access to electronic resources without password

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Fred Hewitt

    2017-08-22

    Described herein are devices and techniques for remotely controlling user access to a restricted computer resource. The process includes obtaining an image from a communication device of a user. An individual and a landmark are identified within the image. Determinations are made that the individual is the user and that the landmark is a predetermined landmark. Access to a restricted computing resource is granted based on the determining that the individual is the user and that the landmark is the predetermined landmark. Other embodiments are disclosed.

  16. impact of the use of electronic resources on research output

    African Journals Online (AJOL)

    manda

    reported using free Internet resources including the search engines, while only a small proportion uses scholarly databases. For example, 22% of researchers reported using the. African Journals Online (AJOL) while 7% use Gale databases (see Table 2 for details). Additionally, the frequency of use also varied significantly ...

  17. Challenges associated with cataloguing of electronic resources in ...

    African Journals Online (AJOL)

    The aim of the paper is to identify challenges associated with the cataloguing of e resources in some selected university libraries in south –south Nigeria. The descriptive survey design involving the use of questionnaire as the research instrument was adopted. The population comprised of cataloguers in five selected ...

  18. X-ray scattering and electron cryomicroscopy study on the effect of carotenoid biosynthesis to the structure of Chlorobium tepidum chlorosomes

    DEFF Research Database (Denmark)

    Ikonen, T P; Li, H; Psencík, J

    2007-01-01

    Chlorosomes, the main antenna complexes of green photosynthetic bacteria, were isolated from null mutants of Chlorobium tepidum, each of which lacked one enzyme involved in the biosynthesis of carotenoids. The effects of the altered carotenoid composition on the structure of the chlorosomes were...... studied by means of x-ray scattering and electron cryomicroscopy. The chlorosomes from each mutant strain exhibited a lamellar arrangement of the bacteriochlorophyll c aggregates, which are the major constituents of the chlorosome interior. However, the carotenoid content and composition had a pronounced...... effect on chlorosome biogenesis and structure. The results indicate that carotenoids with a sufficiently long conjugated system are important for the biogenesis of the chlorosome baseplate. Defects in the baseplate structure affected the shape of the chlorosomes and were correlated with differences...

  19. Availability of Electronic Resources for Service Provision in ...

    African Journals Online (AJOL)

    The study also revealed that majority of the University libraries have adequate basic infrastructure for effective electronic information services. ... acquired by the library are put into maximal use by the library clientele, thereby ensuring the achievement of the library's objective which is satisfying the users, information needs.

  20. Growing an Electronic Library: Resources, Utility, Marketing and Politics.

    Science.gov (United States)

    Dugdale, David; Dugdale, Christine

    2000-01-01

    Describes the development of the ResIDe Electronic Library at the University of the West of England, Bristol. Analyzes potential of the system to increase economy, efficiency and effectiveness in library services and relates it to how the needs of sponsors and students can be met. (Author/LRW)

  1. MODELING OF QUALITY MANAGEMENT SYSTEM FOR ELECTRONIC LEARNING RESOURCES: THE INTEGRATED AND DIFFERENTIATED APPROACHES

    Directory of Open Access Journals (Sweden)

    H. M. Kravtsov

    2012-03-01

    Full Text Available Abstract. Results on modeling of quality management system of electronic information resources on the basis of the analysis of its elements functioning with use of the integrated and differentiated approaches are presented. Application of such model is illustrated on an example of calculation and optimization of parameters of a quality management system at the organization of the co-ordinated work of services of monitoring, an estimation of quality and support of electronic learning resources.

  2. A Study on Developing Evaluation Criteria for Electronic Resources in Evaluation Indicators of Libraries

    Science.gov (United States)

    Noh, Younghee

    2010-01-01

    This study aimed to improve the current state of electronic resource evaluation in libraries. While the use of Web DB, e-book, e-journal, and other e-resources such as CD-ROM, DVD, and micro materials is increasing in libraries, their use is not comprehensively factored into the general evaluation of libraries and may diminish the reliability of…

  3. Managing Selection for Electronic Resources: Kent State University Develops a New System to Automate Selection

    Science.gov (United States)

    Downey, Kay

    2012-01-01

    Kent State University has developed a centralized system that manages the communication and work related to the review and selection of commercially available electronic resources. It is an automated system that tracks the review process, provides selectors with price and trial information, and compiles reviewers' feedback about the resource. It…

  4. Video Killed the Radio Star: Language Students' Use of Electronic Resources-Reading or Viewing?

    Science.gov (United States)

    Kiliçkaya, Ferit

    2016-01-01

    The current study aimed to investigate language students' use of print and electronic resources for their research papers required in research techniques class, focusing on which reading strategies they used while reading these resources. The participants of the study were 90 sophomore students enrolled in the research techniques class offered at…

  5. Where Do Electronic Books Fit in the College Research Arsenal of Resources?

    Science.gov (United States)

    Barbier, Patricia

    2007-01-01

    Student use of electronic books has become an accepted supplement to traditional resources. Student use and satisfaction was monitored through an online course discussion board. Increased use of electronic books indicate this service is an accepted supplement to the print book collection.

  6. Biosynthesis of silver nanoparticles by Aspergillus niger , Fusarium ...

    African Journals Online (AJOL)

    ... scanning electron microscope (SEM). Results indicate the synthesis of silver nanoparticles in the reaction mixture. The synthesis of nanoparticles would be suitable for developing a microbial nanotechnology biosynthesis process for mass scale production. Keywords: Silver nanoparticles, biosynthesis, fungi, Aspergillus.

  7. The National Site Licensing of Electronic Resources: An Institutional Perspective

    Directory of Open Access Journals (Sweden)

    Xiaohua Zhu

    2011-06-01

    Full Text Available While academic libraries in most countries are struggling to negotiate with publishers and vendors individually or collaboratively via consortia, a few countries have experimented with a different model, national site licensing (NSL. Because NSL often involves government and large-scale collaboration, it has the potential to solve many problems in the complex licensing world. However, not many nations have adopted it. This study uses historical research approach and the comparative case study research method to explore the seemingly low level of adoption. The cases include the Canadian National Site Licensing Project (CNSLP, the United Kingdom’s National Electronic Site Licensing Initiative (NESLI, and the United States, which has not adopted NSL. The theoretical framework guiding the research design and data collection is W. Richard Scott’s institutional theory, which utilizes three supporting pillars—regulative, normative, and cultural-cognitive—to analyze institutional processes. In this study, the regulative pillar and the normative pillar of NSL adoption— an institutional construction and change—are examined. Data were collected from monographs, research articles, government documents, and relevant websites. Based on the analysis of these cases, a preliminary model is proposed for the adoption of NSL. The factors that support a country’s adoption of NSL include the need for new institutions, a centralized educational policy-making system and funding system, supportive political trends, and the tradition of cooperation. The factors that may prevent a country from adopting NSL include decentralized educational policy and funding, diversity and the large number of institutions, the concern for the “Big Deal,” and the concern for monopoly.

  8. Use of poisons information resources and satisfaction with electronic products by Victorian emergency department staff.

    Science.gov (United States)

    Luke, Stephen; Fountain, John S; Reith, David M; Braitberg, George; Cruickshank, Jaycen

    2014-10-01

    ED staff use a range of poisons information resources of varying type and quality. The present study aims to identify those resources utilised in the state of Victoria, Australia, and assess opinion of the most used electronic products. A previously validated self-administered survey was conducted in 15 EDs, with 10 questionnaires sent to each. The survey was then repeated following the provision of a 4-month period of access to Toxinz™, an Internet poisons information product novel to the region. The study was conducted from December 2010 to August 2011. There were 117 (78%) and 48 (32%) responses received from the first and second surveys, respectively, a 55% overall response rate. No statistically significant differences in professional group, numbers of poisoned patients seen or resource type accessed were identified between studies. The electronic resource most used in the first survey was Poisindex® (48.68%) and Toxinz™ (64.1%) in the second. There were statistically significant (P poisons information but would do so if a reputable product was available. The order of poisons information sources most utilised was: consultation with a colleague, in-house protocols and electronic resources. There was a significant difference in satisfaction with electronic poisons information resources and a movement away from existing sources when choice was provided. Interest in increased use of mobile solutions was identified. © 2014 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  9. Improving access to information – defining core electronic resources for research and wellbeing

    Directory of Open Access Journals (Sweden)

    Kristiina Hormia-Poutanen

    2007-11-01

    Full Text Available Research and innovation are listed as the key success factors for the future development of Finnish prosperity and the Finnish economy. The Finnish libraries have developed a scenario to support this vision. University, polytechnic and research institute libraries as well as public libraries have defined the core electronic resources necessary to improve access to information in Finland. The primary aim of this work has been to provide information and justification for central funding for electronic resources to support the national goals. The secondary aim is to help with the reallocation of existing central funds to better support access to information.

  10. Analytical Study of Usage of Electronic Information Resources at Pharmacopoeial Libraries in India

    Directory of Open Access Journals (Sweden)

    Sunil Tyagi

    2014-02-01

    Full Text Available The objective of this study is to know the rate and purpose of the use of e-resource by the scientists at pharmacopoeial libraries in India. Among other things, this study examined the preferences of the scientists toward printed books and journals, electronic information resources, and pattern of using e-resources. Non-probability sampling specially accidental and purposive technique was applied in the collection of primary data through administration of user questionnaire. The sample respondents chosen for the study consists of principle scientific officer, senior scientific officer, scientific officer, and scientific assistant of different division of the laboratories, namely, research and development, pharmaceutical chemistry, pharmacovigilance, pharmacology, pharmacogonosy, and microbiology. The findings of the study reveal the personal experiences and perceptions they have had on practice and research activity using e-resource. The major findings indicate that of the total anticipated participants, 78% indicated that they perceived the ability to use computer for electronic information resources. The data analysis shows that all the scientists belonging to the pharmacopoeial libraries used electronic information resources to address issues relating to drug indexes and compendia, monographs, drugs obtained through online databases, e-journals, and the Internet sources—especially polices by regulatory agencies, contacts, drug promotional literature, and standards.

  11. Eavesdropping on Electronic Guidebooks: Observing Learning Resources in Shared Listening Environments

    OpenAIRE

    Woodruff, Allison; Aoki, Paul M.; Grinter, Rebecca E.; Hurst, Amy; Szymanski, Margaret H.; Thornton, James D.

    2002-01-01

    We describe an electronic guidebook, Sotto Voce, that enables visitors to share audio information by eavesdropping on each other's guidebook activity. We have conducted three studies of visitors using electronic guidebooks in a historic house: one study with open air audio played through speakers and two studies with eavesdropped audio. An analysis of visitor interaction in these studies suggests that eavesdropped audio provides more social and interactive learning resources than open air aud...

  12. Elektronik Bilgi Kaynaklarının Seçimi / Selection of Electronic Information Resources

    Directory of Open Access Journals (Sweden)

    Pınar Al

    2003-04-01

    Full Text Available For many years, library users have used only from the printed media in order to get the information that they have needed. Today with the widespread use of the Web and the addition of electronic information resources to library collections, the use of information in the electronic environment as well as in printed media is started to be used. In time, such types of information resources as, electronic journals, electronic books, electronic encyclopedias, electronic dictionaries and electronic theses have been added to library collections. In this study, selection criteria that can be used for electronic information resources are discussed and suggestions are provided for libraries that try to select electronic information resources for their collections.

  13. The Acquisition and Management of Electronic Resources: Can Use Justify Cost?

    Science.gov (United States)

    Koehn, Shona L.; Hawamdeh, Suliman

    2010-01-01

    As library collections increasingly become digital, libraries are faced with many challenges regarding the acquisition and management of electronic resources. Some of these challenges include copyright and fair use, the first-sale doctrine, licensing versus ownership, digital preservation, long-term archiving, and, most important, the issue of…

  14. Awareness and use of electronic resources at a university campus in ...

    African Journals Online (AJOL)

    This study looks into the use of electronic resources by the faculty members of College of Technology Education, Kumasi of the University of Education, Winneba, Ghana. Sixty-two copies of a questionnaire were sent to the entire faculty and 31 were returned which gave a response rate of 50%. The responses showed very ...

  15. Arabinogalactan biosynthesis

    DEFF Research Database (Denmark)

    Poulsen, Christian Peter; Dilokpimol, Adiphol; Geshi, Naomi

    2015-01-01

    Arabinogalactan proteins are abundant cell surface proteoglycans in plants and are implicated to act as developmental markers during plant growth. We previously reported that AtGALT31A, AtGALT29A, and AtGLCAT14A-C, which are involved in the biosynthesis of arabinogalactan proteins, localize......GALT29A. Therefore, the electrostatic status of Y144, which is regulated by an unknown kinase/phosphatase system, may regulate AtGALT29A enzyme activity. Moreover, we have identified additional proteins, apyrase 3 (APY3; At1g14240) and UDPglucuronate epimerases 1 and 6 (GAE1, At4g30440; GAE6, At3g23820...

  16. REVIEW OF MOODLE PLUGINS FOR DESIGNING MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES FROM LANGUAGE DISCIPLINES

    Directory of Open Access Journals (Sweden)

    Anton M. Avramchuk

    2015-09-01

    Full Text Available Today the problem of designing multimedia electronic educational resources from language disciplines in Moodle is very important. This system has a lot of different, powerful resources, plugins to facilitate the learning of students with language disciplines. This article presents an overview and comparative analysis of the five Moodle plugins for designing multimedia electronic educational resources from language disciplines. There have been considered their key features and functionality in order to choose the best for studying language disciplines in the Moodle. Plugins are compared by a group of experts according to the criteria: efficiency, functionality and easy use. For a comparative analysis of the plugins it is used the analytic hierarchy process.

  17. Effects of the Use of Electronic Human Resource Management (EHRM Within Human Resource Management (HRM Functions at Universities

    Directory of Open Access Journals (Sweden)

    Chux Gervase Iwu

    2016-09-01

    Full Text Available This study set out to examine the effect of e-hrm systems in assisting human resource practitioners to execute their duties and responsibilities. In comparison to developed economies of the world, information technology adoption in sub-Saharan Africa has not been without certain glitches. Some of the factors that are responsible for these include poor need identification, sustainable funding, and insufficient skills. Besides these factors, there is also the issue of change management and users sticking to what they already know. Although, the above factors seem negative, there is strong evidence that information systems such as electronic human resource management present benefits to an organization. To achieve this, a dual research approach was utilized. Literature assisted immensely in both the development of the conceptual framework upon which the study hinged as well as in the development of the questionnaire items. The study also made use of an interview checklist to guide the participants. The findings reveal a mix of responses that indicate that while there are gains in adopting e-hrm systems, it is wiser to consider supporting resources as well as articulate the needs of the university better before any investment is made.

  18. USE OF ELECTRONIC EDUCATIONAL RESOURCES WHEN TRAINING IN WORK WITH SPREADSHEETS

    Directory of Open Access Journals (Sweden)

    Х А Гербеков

    2017-12-01

    Full Text Available Today the tools for maintaining training courses based on opportunities of information and communication technologies are developed. Practically in all directions of preparation and on all subject matters electronic textbook and self-instruction manuals are created. Nevertheless the industry of computer educational and methodical materials actively develops and gets more and more areas of development and introduction. In this regard more and more urgent is a problem of development of the electronic educational resources adequate to modern educational requirements. Creation and the organization of training courses with use of electronic educational resources in particular on the basis of Internet technologies remains a difficult methodical task.In article the questions connected with development of electronic educational resources for use when studying the substantial line “Information technologies” of a school course of informatics in particular for studying of spreadsheets are considered. Also the analysis of maintenance of a school course and the unified state examination from the point of view of representation of task in him corresponding to the substantial line of studying “Information technologies” on mastering technology of information processing in spreadsheets and the methods of visualization given by means of charts and schedules is carried out.

  19. Human Mitochondrial Ferredoxin 1 (FDX1) and Ferredoxin 2 (FDX2) Both Bind Cysteine Desulfurase and Donate Electrons for Iron–Sulfur Cluster Biosynthesis

    Science.gov (United States)

    2016-01-01

    Ferredoxins play an important role as an electron donor in iron–sulfur (Fe–S) cluster biosynthesis. Two ferredoxins, human mitochondrial ferredoxin 1 (FDX1) and human mitochondrial ferredoxin 2 (FDX2), are present in the matrix of human mitochondria. Conflicting results have been reported regarding their respective function in mitochondrial iron–sulfur cluster biogenesis. We report here biophysical studies of the interaction of these two ferredoxins with other proteins involved in mitochondrial iron–sulfur cluster assembly. Results from nuclear magnetic resonance spectroscopy show that both FDX1 and FDX2 (in both their reduced and oxidized states) interact with the protein complex responsible for cluster assembly, which contains cysteine desulfurase (NFS1), ISD11 (also known as LYRM4), and acyl carrier protein (Acp). In all cases, ferredoxin residues close to the Fe–S cluster are involved in the interaction with this complex. Isothermal titration calorimetry results showed that FDX2 binds more tightly to the cysteine desulfurase complex than FDX1 does. The reduced form of each ferredoxin became oxidized in the presence of the cysteine desulfurase complex when l-cysteine was added, leading to its conversion to l-alanine and the generation of sulfide. In an in vitro reaction, the reduced form of each ferredoxin was found to support Fe–S cluster assembly on ISCU; the rate of cluster assembly was faster with FDX2 than with FDX1. Taken together, these results show that both FDX1 and FDX2 can function in Fe–S cluster assembly in vitro. PMID:28001042

  20. Alkene hydrogenation activity of enoate reductases for an environmentally benign biosynthesis of adipic acid† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6sc02842j Click here for additional data file.

    Science.gov (United States)

    Khusnutdinova, Anna N.; Flick, Robert; Kim, Taeho; Bornscheuer, Uwe T.

    2017-01-01

    Adipic acid, a precursor for Nylon-6,6 polymer, is one of the most important commodity chemicals, which is currently produced from petroleum. The biosynthesis of adipic acid from glucose still remains challenging due to the absence of biocatalysts required for the hydrogenation of unsaturated six-carbon dicarboxylic acids to adipic acid. Here, we demonstrate the first enzymatic hydrogenation of 2-hexenedioic acid and muconic acid to adipic acid using enoate reductases (ERs). ERs can hydrogenate 2-hexenedioic acid and muconic acid producing adipic acid with a high conversion rate and yield in vivo and in vitro. Purified ERs exhibit a broad substrate spectrum including aromatic and aliphatic 2-enoates and a significant oxygen tolerance. The discovery of the hydrogenation activity of ERs contributes to an understanding of the catalytic mechanism of these poorly characterized enzymes and enables the environmentally benign biosynthesis of adipic acid and other chemicals from renewable resources. PMID:28616142

  1. Directions of use of electronic resources at training to computer science of students of a teacher training college

    OpenAIRE

    Светлана Анатольева Баженова

    2009-01-01

    Article is devoted questions of use of electronic resources at training to computer science in a teacher training college, principles of pedagogical expediency of use of electronic resources at training are specified computer science and positive aspects of such use for different forms of work of the student and the teacher are allocated.

  2. Availability, Level of Use and Constraints to Use of Electronic Resources by Law Lecturers in Public Universities in Nigeria

    Science.gov (United States)

    Amusa, Oyintola Isiaka; Atinmo, Morayo

    2016-01-01

    (Purpose) This study surveyed the level of availability, use and constraints to use of electronic resources among law lecturers in Nigeria. (Methodology) Five hundred and fifty-two law lecturers were surveyed and four hundred and forty-two responded. (Results) Data analysis revealed that the level of availability of electronic resources for the…

  3. A systematic review of portable electronic technology for health education in resource-limited settings.

    Science.gov (United States)

    McHenry, Megan S; Fischer, Lydia J; Chun, Yeona; Vreeman, Rachel C

    2017-08-01

    The objective of this study is to conduct a systematic review of the literature of how portable electronic technologies with offline functionality are perceived and used to provide health education in resource-limited settings. Three reviewers evaluated articles and performed a bibliography search to identify studies describing health education delivered by portable electronic device with offline functionality in low- or middle-income countries. Data extracted included: study population; study design and type of analysis; type of technology used; method of use; setting of technology use; impact on caregivers, patients, or overall health outcomes; and reported limitations. Searches yielded 5514 unique titles. Out of 75 critically reviewed full-text articles, 10 met inclusion criteria. Study locations included Botswana, Peru, Kenya, Thailand, Nigeria, India, Ghana, and Tanzania. Topics addressed included: development of healthcare worker training modules, clinical decision support tools, patient education tools, perceptions and usability of portable electronic technology, and comparisons of technologies and/or mobile applications. Studies primarily looked at the assessment of developed educational modules on trainee health knowledge, perceptions and usability of technology, and comparisons of technologies. Overall, studies reported positive results for portable electronic device-based health education, frequently reporting increased provider/patient knowledge, improved patient outcomes in both quality of care and management, increased provider comfort level with technology, and an environment characterized by increased levels of technology-based, informal learning situations. Negative assessments included high investment costs, lack of technical support, and fear of device theft. While the research is limited, portable electronic educational resources present promising avenues to increase access to effective health education in resource-limited settings, contingent

  4. Model of e-learning with electronic educational resources of new generation

    Directory of Open Access Journals (Sweden)

    A. V. Loban

    2017-01-01

    Full Text Available Purpose of the article: improving of scientific and methodical base of the theory of the е-learning of variability. Methods used: conceptual and logical modeling of the е-learning of variability process with electronic educational resource of new generation and system analysis of the interconnection of the studied subject area, methods, didactics approaches and information and communication technologies means. Results: the formalization complex model of the е-learning of variability with electronic educational resource of new generation is developed, conditionally decomposed into three basic components: the formalization model of the course in the form of the thesaurusclassifier (“Author of e-resource”, the model of learning as management (“Coordination. Consultation. Control”, the learning model with the thesaurus-classifier (“Student”. Model “Author of e-resource” allows the student to achieve completeness, high degree of didactic elaboration and structuring of the studied material in triples of variants: modules of education information, practical task and control tasks; the result of the student’s (author’s of e-resource activity is the thesaurus-classifier. Model of learning as management is based on the principle of personal orientation of learning in computer environment and determines the logic of interaction between the lecturer and the student when determining the triple of variants individually for each student; organization of a dialogue between the lecturer and the student for consulting purposes; personal control of the student’s success (report generation and iterative search for the concept of the class assignment in the thesaurus-classifier before acquiring the required level of training. Model “Student” makes it possible to concretize the learning tasks in relation to the personality of the student and to the training level achieved; the assumption of the lecturer about the level of training of a

  5. Review of material recovery from used electric and electronic equipment-alternative options for resource conservation.

    Science.gov (United States)

    Friege, Henning

    2012-09-01

    For waste from electric and electronic equipment, the WEEE Directive stipulates the separate collection of electric and electronic waste. As to new electric and electronic devices, the Restriction of Hazardous Substances (RoHS) Directive bans the use of certain chemicals dangerous for man and environment. From the implementation of the WEEE directive, many unsolved problems have been documented: poor collection success, emission of dangerous substances during collection and recycling, irretrievable loss of valuable metals among others. As to RoHS, data from the literature show a satisfying success. The problems identified in the process can be reduced to some basic dilemmas at the borders between waste management, product policy and chemical safety. The objectives of the WEEE Directive and the specific targets for use and recycling of appliances are not consistent. There is no focus on scarce resources. Extended producer responsibility is not sufficient to guarantee sustainable waste management. Waste management reaches its limits due to problems of implementation but also due to physical laws. A holistic approach is necessary looking at all branch points and sinks in the stream of used products and waste from electric and electronic equipment. This may be done with respect to the general rules for sustainable management of material streams covering the three dimensions of sustainable policy. The relationships between the players in the field of electric and electronic devices have to be taken into account. Most of the problems identified in the implementation process will not be solved by the current amendment of the WEEE Directive.

  6. [Use of internet and electronic resources among Spanish intensivist physicians. First national survey].

    Science.gov (United States)

    Gómez-Tello, V; Latour-Pérez, J; Añón Elizalde, J M; Palencia-Herrejón, E; Díaz-Alersi, R; De Lucas-García, N

    2006-01-01

    Estimate knowledge and use habits of different electronic resources in a sample of Spanish intensivists: Internet, E-mail, distribution lists, and use of portable electronic devices. Self-applied questionnaire. A 50-question questionnaire was distributed among Spanish intensivists through the hospital marketing delegates of a pharmaceutical company and of electronic forums. A total of 682 questionnaires were analyzed (participation: 74%). Ninety six percent of those surveyed used Internet individually: 67% admitted training gap. Internet was the second source of clinical consultations most used (61%), slightly behind consultation to colleagues (65%). The pages consulted most were bibliographic databases (65%) and electronic professional journals (63%), with limited use of Evidence Based Medicine pages (19%). Ninety percent of those surveyed used e-mail regularly in the practice of their profession, although 25% admitted that were not aware of its possibilities. The use of E-mail decreased significantly with increase in age. A total of 62% of the intensivists used distribution lists. Of the rest, 42% were not aware of its existence and 32% admitted they had insufficient training to handle them. Twenty percent of those surveyed had portable electronic devices and 64% considered it useful, basically due to its rapid consultation at bedside. Female gender was a negative predictive factor of its use (OR 0.35; 95% CI 0.2-0.63; p=0.0002). A large majority of the Spanish intensivists use Internet and E-mail. E-mail lists and use of portable devices are still underused resources. There are important gaps in training and infrequent use of essential pages. There are specific groups that require directed educational policies.

  7. Comparing Electronic Human Resource Management Systems Efficiency In Production Organization amp Service Organizations

    Directory of Open Access Journals (Sweden)

    Ali Hadian

    2015-08-01

    Full Text Available Today the organizations used information technology in performing human resource department affairs and this is called as electronic human resource management EHRM. In fact as the competitive complexity increases the need for implementing EHRM in production and service businesses increases too. This paper is written in order to specify the importance of implementing EHRM in production and service organizations and also to evaluate efficiency rate and the importance degree in these two ones. In this paper first the topics literature and the most important aspects of implementing these systems will be reviewed and after categorizing these views the hierarchal model will be proposed by applying AHP method. The result of analyzing this model by EXPERT CHOICE software shows that implementing EHRM in both kinds of organizations has the same importance however there is a large difference between them in implementing aspects.

  8. The Synthesis of the Hierarchical Structure of Information Resources for Management of Electronic Commerce Entities

    Directory of Open Access Journals (Sweden)

    Krutova Anzhelika S.

    2017-06-01

    Full Text Available The aim of the article is to develop the theoretical bases for the classification and coding of economic information and the scientific justification of the content of information resources of an electronic commerce enterprise. The essence of information resources for management of electronic business entities is investigated. It is proved that the organization of accounting in e-commerce systems is advisable to be built on the basis of two circuits: accounting for financial flows and accounting associated with transformation of business factors in products and services as a result of production activities. There presented a sequence of accounting organization that allows to combine the both circuits in a single information system, which provides a possibility for the integrated replenishment and distributed simultaneous use of the e-commerce system by all groups of users. It is proved that the guarantee of efficient activity of the information management system of electronic commerce entities is a proper systematization of the aggregate of information resources on economic facts and operations of an enterprise in accordance with the management tasks by building the hierarchy of accounting nomenclatures. It is suggested to understand nomenclature as an objective, primary information aggregate concerning a certain fact of the economic activity of an enterprise, which is characterized by minimum requisites, is entered into the database of the information system and is to be reflected in the accounting system. It is proposed to build a database of e-commerce systems as a part of directories (constants, personnel, goods / products, suppliers, buyers and the hierarchy of accounting nomenclatures. The package of documents regulating the organization of accounting at an enterprise should include: the provision on the accounting services, the order on the accounting policy, the job descriptions, the schedules of information exchange, the report card and

  9. Assessment of a land-locked Atlantic salmon (Salmo salar L.) population as a potential genetic resource with a focus on long-chain polyunsaturated fatty acid biosynthesis.

    Science.gov (United States)

    Betancor, M B; Olsen, R E; Solstorm, D; Skulstad, O F; Tocher, D R

    2016-03-01

    The natural food for Atlantic salmon (Salmo salar) in freshwater has relatively lower levels of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA) than found in prey for post-smolt salmon in seawater. Land-locked salmon such as the Gullspång population feed exclusively on freshwater type lipids during its entire life cycle, a successful adaptation derived from divergent evolution. Studying land-locked populations may provide insights into the molecular and genetic control mechanisms that determine and regulate n-3 LC-PUFA biosynthesis and retention in Atlantic salmon. A two factorial study was performed comparing land-locked and farmed salmon parr fed diets formulated with fish or rapeseed oil for 8 weeks. The land-locked parr had higher capacity to synthesise n-3 LC-PUFA as indicated by higher expression and activity of desaturase and elongase enzymes. The data suggested that the land-locked salmon had reduced sensitivity to dietary fatty acid composition and that dietary docosahexaenoic acid (DHA) did not appear to suppress expression of LC-PUFA biosynthetic genes or activity of the biosynthesis pathway, probably an evolutionary adaptation to a natural diet lower in DHA. Increased biosynthetic activity did not translate to enhanced n-3 LC-PUFA contents in the flesh and diet was the only factor affecting this parameter. Additionally, high lipogenic and glycolytic potentials were found in land-locked salmon, together with decreased lipolysis which in turn could indicate increased use of carbohydrates as an energy source and a sparing of lipid. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. THE MODEL OF LINGUISTIC TEACHERS’ COMPETENCY DEVELOPMENT ON DESIGNING MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES IN THE MOODLE SYSTEM

    Directory of Open Access Journals (Sweden)

    Anton M. Avramchuk

    2017-10-01

    Full Text Available The article is devoted to the problem of developing the competency of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system. The concept of "the competence of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system" is justified and defined. Identified and characterized the components by which the levels of the competency development of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system should be assessed. Developed a model for the development of the competency of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system, which is based on the main scientific approaches, used in adult education, and consists of five blocks: target, informative, technological, diagnostic and effective.

  11. Open-Source Electronic Health Record Systems for Low-Resource Settings: Systematic Review.

    Science.gov (United States)

    Syzdykova, Assel; Malta, André; Zolfo, Maria; Diro, Ermias; Oliveira, José Luis

    2017-11-13

    Despite the great impact of information and communication technologies on clinical practice and on the quality of health services, this trend has been almost exclusive to developed countries, whereas countries with poor resources suffer from many economic and social issues that have hindered the real benefits of electronic health (eHealth) tools. As a component of eHealth systems, electronic health records (EHRs) play a fundamental role in patient management and effective medical care services. Thus, the adoption of EHRs in regions with a lack of infrastructure, untrained staff, and ill-equipped health care providers is an important task. However, the main barrier to adopting EHR software in low- and middle-income countries is the cost of its purchase and maintenance, which highlights the open-source approach as a good solution for these underserved areas. The aim of this study was to conduct a systematic review of open-source EHR systems based on the requirements and limitations of low-resource settings. First, we reviewed existing literature on the comparison of available open-source solutions. In close collaboration with the University of Gondar Hospital, Ethiopia, we identified common limitations in poor resource environments and also the main requirements that EHRs should support. Then, we extensively evaluated the current open-source EHR solutions, discussing their strengths and weaknesses, and their appropriateness to fulfill a predefined set of features relevant for low-resource settings. The evaluation methodology allowed assessment of several key aspects of available solutions that are as follows: (1) integrated applications, (2) configurable reports, (3) custom reports, (4) custom forms, (5) interoperability, (6) coding systems, (7) authentication methods, (8) patient portal, (9) access control model, (10) cryptographic features, (11) flexible data model, (12) offline support, (13) native client, (14) Web client,(15) other clients, (16) code

  12. A preliminary categorization of end-of-life electrical and electronic equipment as secondary metal resources

    International Nuclear Information System (INIS)

    Oguchi, Masahiro; Murakami, Shinsuke; Sakanakura, Hirofumi; Kida, Akiko; Kameya, Takashi

    2011-01-01

    Highlights: → End-of-life electrical and electronic equipment (EEE) as secondary metal resources. → The content and the total amount of metals in specific equipment are both important. → We categorized 21 EEE types from contents and total amounts of various metals. → Important equipment types as secondary resources were listed for each metal kind. → Collectability and possible collection systems of various EEE types were discussed. - Abstract: End-of-life electrical and electronic equipment (EEE) has recently received attention as a secondary source of metals. This study examined characteristics of end-of-life EEE as secondary metal resources to consider efficient collection and metal recovery systems according to the specific metals and types of EEE. We constructed an analogy between natural resource development and metal recovery from end-of-life EEE and found that metal content and total annual amount of metal contained in each type of end-of-life EEE should be considered in secondary resource development, as well as the collectability of the end-of-life products. We then categorized 21 EEE types into five groups and discussed their potential as secondary metal resources. Refrigerators, washing machines, air conditioners, and CRT TVs were evaluated as the most important sources of common metals, and personal computers, mobile phones, and video games were evaluated as the most important sources of precious metals. Several types of small digital equipment were also identified as important sources of precious metals; however, mid-size information and communication technology (ICT) equipment (e.g., printers and fax machines) and audio/video equipment were shown to be more important as a source of a variety of less common metals. The physical collectability of each type of EEE was roughly characterized by unit size and number of end-of-life products generated annually. Current collection systems in Japan were examined and potentially appropriate collection

  13. Determining the level of awareness of the physicians in using the variety of electronic information resources and the effecting factors.

    Science.gov (United States)

    Papi, Ahmad; Ghazavi, Roghayeh; Moradi, Salimeh

    2015-01-01

    Understanding of the medical society's from the types of information resources for quick and easy access to information is an imperative task in medical researches and management of the treatment. The present study was aimed to determine the level of awareness of the physicians in using various electronic information resources and the factors affecting it. This study was a descriptive survey. The data collection tool was a researcher-made questionnaire. The study population included all the physicians and specialty physicians of the teaching hospitals affiliated to Isfahan University of Medical Sciences and numbered 350. The sample size based on Morgan's formula was set at 180. The content validity of the tool was confirmed by the library and information professionals and the reliability was 95%. Descriptive statistics were used including the SPSS software version 19. On reviewing the need of the physicians to obtain the information on several occasions, the need for information in conducting the researches was reported by the maximum number of physicians (91.9%) and the usage of information resources, especially the electronic resources, formed 65.4% as the highest rate with regard to meeting the information needs of the physicians. Among the electronic information databases, the maximum awareness was related to Medline with 86.5%. Among the various electronic information resources, the highest awareness (43.3%) was related to the E-journals. The highest usage (36%) was also from the same source. The studied physicians considered the most effective deterrent in the use of electronic information resources as being too busy and lack of time. Despite the importance of electronic information resources for the physician's community, there was no comprehensive knowledge of these resources. This can lead to less usage of these resources. Therefore, careful planning is necessary in the hospital libraries in order to introduce the facilities and full capabilities of the

  14. Resource conservation approached with an appropriate collection and upgrade-remanufacturing for used electronic products.

    Science.gov (United States)

    Zlamparet, Gabriel I; Tan, Quanyin; Stevels, A B; Li, Jinhui

    2018-03-01

    This comparative research represents an example for a better conservation of resources by reducing the amount of waste (kg) and providing it more value under the umbrella of remanufacturing. The three discussed cases will expose three issues already addressed separately in the literature. The generation of waste electrical and electronic equipment (WEEE) interacts with the environmental depletion. In this article, we gave the examples of addressed issues under the concept of remanufacturing. Online collection opportunity eliminating classical collection, a business to business (B2B) implementation for remanufactured servers and medical devices. The material reuse (recycling), component sustainability, reuse (part harvesting), product reuse (after repair/remanufacturing) indicates the recovery potential using remanufacturing tool for a better conservation of resources adding more value to the products. Our findings can provide an overview of new system organization for the general collection, market potential and the technological advantages using remanufacturing instead of recycling of WEEE or used electrical and electronic equipment. Copyright © 2017. Published by Elsevier Ltd.

  15. Use of Electronic Resources by M.Sc. Chemistry Students at Arts Science and Commerce College Chopda Dist-Jalgaon

    OpenAIRE

    Dr.Paithankar Rajeev; R., Mr.Kamble V.R.

    2017-01-01

    The libraries and information services has been changed due to the development of information and communication technology. Electronics resources role is very important as information repositories are use of information for various purposes like academic, research, teaching and learning process. E-resources gives solutions of the traditional libraries as like all data storage in digital format, users can access library without boundaries through internet so e-resources popularity is very cont...

  16. Making the Right Connections: Perceptions of Human Resource/Personnel Directors Concerning Electronic Job-Search Methods.

    Science.gov (United States)

    Hubbard, Joan C.; North, Alexa B.; Arjomand, H. Lari

    1997-01-01

    Examines methods used to search for entry-level managerial positions and assesses how human resource and personnel directors in Georgia perceive these methods. Findings indicate that few of the directors use electronic technology to fill such positions, but they view positively those applicants who use electronic job searching methods. (RJM)

  17. From Millennium ERM to Proquest 360 Resource Manager: Implementing a new Electronic Resources Management System ERMS in an International Graduate Research University in Saudi Arabia

    KAUST Repository

    Ramli, Rindra M.

    2017-05-17

    An overview of the Recommendation Study and the subsequent Implementation of a new Electronic Resources Management system ERMS in an international graduate research university in the Kingdom of Saudi Arabia. It covers the timeline, deliverables and challenges as well as lessons learnt by the Project Team.

  18. Biosynthesis of silver nanoparticles.

    Science.gov (United States)

    Poulose, Subin; Panda, Tapobrata; Nair, Praseetha P; Théodore, Thomas

    2014-02-01

    Metal nanoparticles have unique optical, electronic, and catalytic properties. There exist well-defined physical and chemical processes for their preparation. Those processes often yield small quantities of nanoparticles having undesired morphology, and involve high temperatures for the reaction and the use of hazardous chemicals. Relatively, the older technique of bioremediation of metals uses either microorganisms or their components for the production of nanoparticles. The nanoparticles obtained from bacteria, fungi, algae, plants and their components, etc. appear environment-friendly, as toxic chemicals are not used in the processes. In addition to this, the formation of nanoparticles takes place at almost normal temperature and pressure. Control of the shape and size of the nanoparticles is possible by appropriate selection of the pH and temperature. Three important steps are the bioconversion of Ag+ ions, conversion of desired crystals to nanoparticles, and nanoparticle stability. Generally, nanoparticles are characterized by the UV-visible spectroscopy and use of the electron microscope. Silver nanoparticles are used as antimicrobial agents and they possess antifungal, anti-inflammatory, and anti-angiogenic properties. This review highlights the biosynthesis of silver nanoparticles by various organisms, possible mechanisms of their synthesis, their characterization, and applications of silver nanoparticles.

  19. Electronic tracking of human resource skills and knowledge, just in time training, manageable due diligence

    Energy Technology Data Exchange (ETDEWEB)

    Kolodziej, M.A. [Quick Test International Inc., (Canada). Canadian Technology Human Resource Board; Baker, O. [KeySpan Energy Canada, Calgary, AB (Canada)

    2001-06-01

    KeySpan Energy Canada is in the process of obtaining recognition of various occupational profiles including pipeline operators, inspectors, and field and plant operators from various certifying organizations. The process of allowing individuals to obtain certification is recognized by Canadian Technology Human Resources Board as a step towards national standards for technologists and technicians. Proven competency is a must for workers in todays oil industry in response to increasingly stringent government safety regulations, environmental concerns and high public scrutiny. Quick Test international Inc. has developed a management tool in collaboration with end users at KeySpan Energy Canada. It is an electronic, Internet based competency tool for tracking personal competencies and maintaining continued competency. Response to the tool has been favourable. 2 refs., 4 figs.

  20. DEVELOPMENT AND USAGE OF THE ELECTRONIC VIDEO RESOURCES FOR EDUCATIONAL PURPOSES

    Directory of Open Access Journals (Sweden)

    Yaroslav M. Hlynsky

    2017-04-01

    Full Text Available This article discusses the theoretical foundation, the creation and implementation of the electronic educational video resources (EEVR in the example of the development and the usage of the collection of video tutorials in event-driven programming theme, which is studied in the framework of the subject "Informatics" by students of many specialties. It offers some development of the existing conceptual and categorical apparatus concerning EEVR development. It is alleged that the video tutorials allow you to automate the process of learning, redistribute instructional time for the benefit of students' independent work, to provide classroom release time for the teaching of the theoretical issues of the course that is aimed at improving the fundamental nature of training. Practical recommendations for the development of the effective EEVR, which may be useful for the authors of e-learning courses for students of different forms of training are proposed.

  1. Availability, Use and Constraints to Use of Electronic Information Resources by Postgraduates Students at the University of Ibadan

    Directory of Open Access Journals (Sweden)

    Dare Samuel Adeleke

    2017-12-01

    Full Text Available Availability, awareness and use of electronic resources provide access to authoritative, reliable, accurate and timely access to information. The use of electronic information resources (EIRs can enable innovation in teaching and increase timeliness in research of postgraduate students which will eventual result into encouragement of the expected research-led enquiry in this digital age. The study adopted a descriptive survey design. Samples of 300 of postgraduate students within seven out 13 Faculties were randomly selected. Data were collected using questionnaire designed to elicit response from respondents and data were analyzed using descriptive statistics methods percentages, mean, and standard deviation. Results indicated that internet was ranked most available and used in the university. Low level of usage of electronic resources, in particular, full texts data bases is linked to a number of constraints: Interrupted power supply was ranked highest among other factors as speed and capacity of computers, retrieval of records with high recall and low precision, retrieving records relevant to information need, lack of knowledge of search techniques to retrieve information effectively, non possession of requisite IT skills and problems accessing the internet. The study recommended that usage of electronic resources be made compulsory, intensifying awareness campaigns concerning the availability, training on use of electronic resources and the problem of power outage be addressed.

  2. Genetic-algorithm-based optimization of a fuzzy logic resource manager for electronic attack

    Science.gov (United States)

    Smith, James F., III; Rhyne, Robert D., II

    2000-04-01

    A fuzzy logic based expert system has been developed that automatically allocates electronic attack (EA) resources in real-time over many dissimilar platforms. The platforms can be very general, e.g., ships, planes, robots, land based facilities, etc. Potential foes the platforms deal with can also be general. This paper describes data mining activities related to development of the resource manager with a focus on genetic algorithm based optimization. A genetic algorithm requires the construction of a fitness function, a function that must be maximized to give optimal or near optimal results. The fitness functions are in general non- differentiable at many points and highly non-linear, neither property providing difficulty for a genetic algorithm. The fitness functions are constructed using insights from geometry, physics, engineering, and military doctrine. Examples are given as to how fitness functions are constructed including how the fitness function is averaged over a database of military scenarios. The use of a database of scenarios prevents the algorithm from having too narrow a range of behaviors, i.e., it creates a more robust solution.

  3. Factors Influencing Students' Use of Electronic Resources and their Opinions About this Use: The Case of Students at An-Najah National University

    Directory of Open Access Journals (Sweden)

    Wajeeh M. Daher

    2010-12-01

    Full Text Available Electronic resources are becoming an integral part of the modern life and of the educational scene, especially the high education scene. In this research we wanted to verify what influences first degree university students' use of electronic resources and their opinions regarding this use. Collecting data from 202 students and analyzing it using SPSS, we found that more than one half of the participants had high level of electronic media use and more than one third had moderate level of electronic media use. These levels of use indicate the students' awareness of the role and benefits of electronic media use. Regarding the factors that influence the students' se of electronic resources we found that the student's use of electronic resources had significant strong positive relationships with the provision of electronic resources by the academic institution. It had significant moderate positive relationships with the resources characteristics and the course requirement, and had significant weak relationships with the instructor's support and the student's characteristics. We explained these relationships as resulting from the influence of the surrounding community. Regarding the students' opinions about the use of electronic resources, we found that the student's opinion of electronic resources has significant strong positive relationships with student's use of electronic resources, level of this use, the academic institution available facilities, student's characteristics and resources characteristics. It does not have significant relationships with the instructor's support or the course requirement. We explained these relationships depending on activity theory and its integration with ecological psychology.

  4. The electronic encapsulation of knowledge in hydraulics, hydrology and water resources

    Science.gov (United States)

    Abbott, Michael B.

    The rapidly developing practice of encapsulating knowledge in electronic media is shown to lead necessarily to the restructuring of the knowledge itself. The consequences of this for hydraulics, hydrology and more general water-resources management are investigated in particular relation to current process-simulation, real-time control and advice-serving systems. The generic properties of the electronic knowledge encapsulator are described, and attention is drawn to the manner in which knowledge 'goes into hiding' through encapsulation. This property is traced in the simple situations of pure mathesis and in the more complex situations of taxinomia using one example each from hydraulics and hydrology. The consequences for systems architectures are explained, pointing to the need for multi-agent architectures for ecological modelling and for more general hydroinformatics systems also. The relevance of these developments is indicated by reference to ongoing projects in which they are currently being realised. In conclusion, some more general epistemological aspects are considered within the same context. As this contribution is so much concerned with the processes of signification and communication, it has been partly shaped by the theory of semiotics, as popularised by Eco ( A Theory of Semiotics, Indiana University, Bloomington, 1977).

  5. Resources

    Science.gov (United States)

    English in Australia, 1973

    1973-01-01

    Contains seven short resources''--units, lessons, and activities on the power of observation, man and his earth, snakes, group discussion, colloquial and slang, the continuous story, and retelling a story. (DD)

  6. THE FACTOR-CRITERIA MODEL OF ASSESSMENT OF ELECTRONIC EDUCATIONAL GAME RESOURCES IN MATHEMATICS FOR PRIMARY SCHOOL STUDENTS

    Directory of Open Access Journals (Sweden)

    Oksana M. Melnyk

    2016-05-01

    Full Text Available This article proves the need for a comprehensive assessment of electronic educational game resources in mathematics for the primary school students; gives the definition of “the factor-criteria model of the electronic educational game resources (EEGR”. It also describes the created model, which consists of requirements for the content, methodological and program parts of the electronic resources for primary school; identifies the factors and the criteria to each of them. It was proposed to assess the ratios within the group of factors and each group of criteria according to the arithmetic progression. The presented model can be a convenient tool both for primary school teachers and EEGR developers. It can also be a basis for a unified state comprehensive system of assessment of the EEGR.

  7. SAGES: a suite of freely-available software tools for electronic disease surveillance in resource-limited settings.

    Directory of Open Access Journals (Sweden)

    Sheri L Lewis

    Full Text Available Public health surveillance is undergoing a revolution driven by advances in the field of information technology. Many countries have experienced vast improvements in the collection, ingestion, analysis, visualization, and dissemination of public health data. Resource-limited countries have lagged behind due to challenges in information technology infrastructure, public health resources, and the costs of proprietary software. The Suite for Automated Global Electronic bioSurveillance (SAGES is a collection of modular, flexible, freely-available software tools for electronic disease surveillance in resource-limited settings. One or more SAGES tools may be used in concert with existing surveillance applications or the SAGES tools may be used en masse for an end-to-end biosurveillance capability. This flexibility allows for the development of an inexpensive, customized, and sustainable disease surveillance system. The ability to rapidly assess anomalous disease activity may lead to more efficient use of limited resources and better compliance with World Health Organization International Health Regulations.

  8. Utilization of Electronic Information Resources by Undergraduate Students of University of Ibadan: A Case Study of Social Sciences and Education

    Science.gov (United States)

    Owolabi, Sola; Idowu, Oluwafemi A.; Okocha, Foluke; Ogundare, Atinuke Omotayo

    2016-01-01

    The study evaluated utilization of electronic information resources by undergraduates in the Faculties of Education and the Social Sciences in University of Ibadan. The study adopted a descriptive survey design with a study population of 1872 undergraduates in the Faculties of Education and the Social Sciences in University of Ibadan, from which a…

  9. Impact of Electronic Resources and Usage in Academic Libraries in Ghana: Evidence from Koforidua Polytechnic & All Nations University College, Ghana

    Science.gov (United States)

    Akussah, Maxwell; Asante, Edward; Adu-Sarkodee, Rosemary

    2015-01-01

    The study investigates the relationship between impact of electronic resources and its usage in academic libraries in Ghana: evidence from Koforidua Polytechnic & All Nations University College, Ghana. The study was a quantitative approach using questionnaire to gather data and information. A valid response rate of 58.5% was assumed. SPSS…

  10. Systematic review of electronic surveillance of infectious diseases with emphasis on antimicrobial resistance surveillance in resource-limited settings.

    Science.gov (United States)

    Rattanaumpawan, Pinyo; Boonyasiri, Adhiratha; Vong, Sirenda; Thamlikitkul, Visanu

    2018-02-01

    Electronic surveillance of infectious diseases involves rapidly collecting, collating, and analyzing vast amounts of data from interrelated multiple databases. Although many developed countries have invested in electronic surveillance for infectious diseases, the system still presents a challenge for resource-limited health care settings. We conducted a systematic review by performing a comprehensive literature search on MEDLINE (January 2000-December 2015) to identify studies relevant to electronic surveillance of infectious diseases. Study characteristics and results were extracted and systematically reviewed by 3 infectious disease physicians. A total of 110 studies were included. Most surveillance systems were developed and implemented in high-income countries; less than one-quarter were conducted in low-or middle-income countries. Information technologies can be used to facilitate the process of obtaining laboratory, clinical, and pharmacologic data for the surveillance of infectious diseases, including antimicrobial resistance (AMR) infections. These novel systems require greater resources; however, we found that using electronic surveillance systems could result in shorter times to detect targeted infectious diseases and improvement of data collection. This study highlights a lack of resources in areas where an effective, rapid surveillance system is most needed. The availability of information technology for the electronic surveillance of infectious diseases, including AMR infections, will facilitate the prevention and containment of such emerging infectious diseases. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  11. The Use of Electronic Resources by Academic Staff at the University of Ilorin, Nigeria

    Science.gov (United States)

    Tella, Adeyinka; Orim, Faith; Ibrahim, Dauda Morenikeji; Memudu, Suleiman Ajala

    2018-01-01

    The use of e-resources is now commonplace among academics in tertiary educational institutions the world over. Many academics including those in the universities are exploring the opportunities of e-resources to facilitate teaching and research. As the use of e-resources is increasing particularly among academics at the University of Ilorin,…

  12. Use and Cost of Electronic Resources in Central Library of Ferdowsi University Based on E-metrics

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Davarpanah

    2012-07-01

    Full Text Available The purpose of this study was to investigate the usage of electronic journals in Ferdowsi University, Iran based on e-metrics. The paper also aimed to emphasize the analysis of cost-benefit and the correlation between the journal impact factors and the usage data. In this study experiences of Ferdowsi University library on licensing and usage of electronic resources was evaluated by providing a cost-benefit analysis based on the cost and usage statistics of electronic resources. Vendor-provided data were also compared with local usage data. The usage data were collected by tracking web-based access locally, and by collecting vender-provided usage data. The data sources were one-year of vendor-supplied e-resource usage data such as Ebsco, Elsevier, Proquest, Emerald, Oxford and Springer and local usage data collected from the Ferdowsi university web server. The study found that actual usage values differ for vendor-provided data and local usage data. Elsevier has got the highest usage degree in searches, sessions and downloads. Statistics also showed that a small number of journals satisfy significant amount of use while the majority of journals were used less frequent and some were never used at all. The users preferred the PDF rather than HTML format. The data in subject profile suggested that the provided e-resources were best suited to certain subjects. There was no correlation between IF and electronic journal use. Monitoring the usage of e-resources gained increasing importance for acquisition policy and budget decisions. The article provided information about local metrics for the six surveyed vendors/publishers, e.g. usage trends, requests per package, cost per use as related to the scientific specialty of the university.

  13. Changes in Charge Distribution, Molecular Volume, Accessible Surface Area and Electronic Structure along the Reaction Coordinate for a Carbocationic Triple Shift Rearrangement of Relevance to Diterpene Biosynthesis

    Czech Academy of Sciences Publication Activity Database

    Hong, Y.J.; Ponec, Robert; Tantillo, D.J.

    2012-01-01

    Roč. 116, č. 35 (2012), s. 8902-8909 ISSN 1089-5639 R&D Projects: GA ČR GA203/09/0118 Grant - others:NSF(US) CHE-0957416; NSF(US) CHE-030089 Institutional support: RVO:67985858 Keywords : carbocationic rearraangements * electron reorganization * multicenter bonding Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.771, year: 2012

  14. Challenges for international students in using electronic resources in the Learning Centre : a case study of Oslo University College

    OpenAIRE

    Rahman, Md. Anisur

    2011-01-01

    Joint Master Degree in Digital Library Learning (DILL) The purpose of this study is to find out the challenges facing by international students in using electronic resources in the OUC learning center. This research has used a qualitative approach and purposive, a non-probability techniques used for sampling of this study. A semi-structured face-to-face interviews method is used for the collection of data. The interview questions were open ended and the discourse analysis metho...

  15. RESEARCH OF INFLUENCE OF QUALITY OF ELECTRONIC EDUCATIONAL RESOURCES ON QUALITY OF TRAINING WITH USE OF DISTANCE TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    H. M. Kravtsov

    2013-03-01

    Full Text Available Communication improving of educational processes requires today new approaches to the management arrangements and forming of educational policy in the field of distance learning, which is based on the use of modern information and communication technologies. An important step in this process is the continuous monitoring of the development and implementation of information technology and, in particular, the distance learning systems in higher educational establishments. The main objective of the monitoring is the impact assessment on the development of distance learning following the state educational standards, curricula, methodical and technical equipment and other factors; factors revelation that influence the implementation and outcomes of distance learning; results comparison of educational institution functioning and distance education systems in order to determine the most efficient ways of its development. The paper presents the analysis results of the dependence of the quality of educational services on the electronic educational resources. Trends in educational services development was studied by comparing the quality influence of electronic educational resources on the quality of educational services of higher pedagogical educational institutions of Ukraine as of 2009-2010 and 2012-2013. Generally, the analysis of the survey results allows evaluating quality of the modern education services as satisfactory and it can be said that almost 70% of the success of their future development depends on the quality of the used electronic educational resources and distance learning systems in particular.

  16. Biosynthesis of tylophora alkaloids

    International Nuclear Information System (INIS)

    Mulchandani, N.B.; Iyer, S.S.; Badheka, L.P.

    1974-01-01

    Using labelled precursors, biosynthesis of the tylophora alkaloids, tylophorine, tylophorinidine and tylophorinide has been investigated in Tylophora asthmatica plants. The radioactive precursors, phenylalanine-2- 14 C, benzoic acid-1- 14 C, benzoic acid-ring 14 C, acetate-2- 14 C, ornithine-5- 14 C, acetate-2- 14 C, ornithine-5- 14 C and cinnamic acid-2- 14 C were administered to the plants individually by wick technique. Tylophorine was isolated in each case and assayed for its radioactivity to find out the incorporation of the label into it. The results indicate that: (1) phenylalanine via cinnamic acid is an important precursor in the biosynthesis of tylophorine (2) orinithine participates in tylophorine biosynthesis via pyrroline and (3) tylophorinidine may be a direct precursor of tylophorine. (M.G.B.)

  17. Aflatoxin biosynthesis: current frontiers.

    Science.gov (United States)

    Roze, Ludmila V; Hong, Sung-Yong; Linz, John E

    2013-01-01

    Aflatoxins are among the principal mycotoxins that contaminate economically important food and feed crops. Aflatoxin B1 is the most potent naturally occurring carcinogen known and is also an immunosuppressant. Occurrence of aflatoxins in crops has vast economic and human health impacts worldwide. Thus, the study of aflatoxin biosynthesis has become a focal point in attempts to reduce human exposure to aflatoxins. This review highlights recent advances in the field of aflatoxin biosynthesis and explores the functional connection between aflatoxin biosynthesis, endomembrane trafficking, and response to oxidative stress. Dissection of the regulatory mechanisms involves a complete comprehension of the aflatoxin biosynthetic process and the dynamic network of transcription factors that orchestrates coordinated expression of the target genes. Despite advancements in the field, development of a safe and effective multifaceted approach to solve the aflatoxin food contamination problem is still required.

  18. Tracking the Flow of Resources in Electronic Waste - The Case of End-of-Life Computer Hard Disk Drives.

    Science.gov (United States)

    Habib, Komal; Parajuly, Keshav; Wenzel, Henrik

    2015-10-20

    Recovery of resources, in particular, metals, from waste flows is widely seen as a prioritized option to reduce their potential supply constraints in the future. The current waste electrical and electronic equipment (WEEE) treatment system is more focused on bulk metals, where the recycling rate of specialty metals, such as rare earths, is negligible compared to their increasing use in modern products, such as electronics. This study investigates the challenges in recovering these resources in the existing WEEE treatment system. It is illustrated by following the material flows of resources in a conventional WEEE treatment plant in Denmark. Computer hard disk drives (HDDs) containing neodymium-iron-boron (NdFeB) magnets were selected as the case product for this experiment. The resulting output fractions were tracked until their final treatment in order to estimate the recovery potential of rare earth elements (REEs) and other resources contained in HDDs. The results further show that out of the 244 kg of HDDs treated, 212 kg comprising mainly of aluminum and steel can be finally recovered from the metallurgic process. The results further demonstrate the complete loss of REEs in the existing shredding-based WEEE treatment processes. Dismantling and separate processing of NdFeB magnets from their end-use products can be a more preferred option over shredding. However, it remains a technological and logistic challenge for the existing system.

  19. HELP (INFORMATION ELECTRONIC RESOURCE "CHRONICLE OF ONU: DATES, FACTS, EVENTS": HISTORY OF UNIVERSITY IN INFORMATION SPACE

    Directory of Open Access Journals (Sweden)

    А. М. Гавриленко

    2016-03-01

    Object of research is the help information resource "The chronicle of the Odessa national university of I. I. Mechnikov: dates, facts, events". The main objective of our article – to state the main methodological bases of creation of information resource. One of advantages of information resource is possibility of continuous updating and replenishment by new information. Main objective of creation of this information resource is systematization of material on stories of the Odessa national university of I. I. Mechnikov from the date of his basis to the present, ensuring interactive access to information on the main dates, the most significant events in life of university. The base of research are sources on the history of university, chronology of historical development, formation of infrastructure, cadres and scientific researches. In information resource the main stages of development, functioning and transformation of the Odessa University are analyzed, information on its divisions is collected. For creation of this information resource in Scientific library the method of work was developed, the main selection criteria of data are allocated. This information resource have practical value for all who is interested in history of university, historians, scientists-researchers of history of science and the city of Odessa.

  20. Effect of Access to an Electronic Medical Resource on Performance Characteristics of a Certification Examination: A Randomized Controlled Trial.

    Science.gov (United States)

    Lipner, Rebecca S; Brossman, Bradley G; Samonte, Kelli M; Durning, Steven J

    2017-09-05

    Electronic resources are increasingly used in medical practice. Their use during high-stakes certification examinations has been advocated by many experts, but whether doing so would affect the capacity to differentiate between high and low abilities is unknown. To determine the effect of electronic resources on examination performance characteristics. Randomized controlled trial. Medical certification program. 825 physicians initially certified by the American Board of Internal Medicine (ABIM) who passed the Internal Medicine Certification examination or sat for the Internal Medicine Maintenance of Certification (IM-MOC) examination in 2012 to 2015. Participants were randomly assigned to 1 of 4 conditions: closed book using typical or additional time, or open book (that is, UpToDate [Wolters Kluwer]) using typical or additional time. All participants took the same modified version of the IM-MOC examination. Primary outcomes included item difficulty (how easy or difficult the question was), item discrimination (how well the question differentiated between high and low abilities), and average question response time. Secondary outcomes included examination dimensionality (that is, the number of factors measured) and test-taking strategy. Item response theory was used to calculate question characteristics. Analysis of variance compared differences among conditions. Closed-book conditions took significantly less time than open-book conditions (mean, 79.2 seconds [95% CI, 78.5 to 79.9 seconds] vs. 110.3 seconds [CI, 109.2 to 111.4 seconds] per question). Mean discrimination was statistically significantly higher for open-book conditions (0.34 [CI, 0.32 to 0.35] vs. 0.39 [CI, 0.37 to 0.41] per question). A strong single dimension showed that the examination measured the same factor with or without the resource. Only 1 electronic resource was evaluated. Inclusion of an electronic resource with time constraints did not adversely affect test performance and did not change

  1. The level of the usage of the human resource information system and electronic recruitment in Croatian companies

    Directory of Open Access Journals (Sweden)

    Snježana Pivac

    2014-12-01

    Full Text Available Performing business according to contemporary requirements influences companies for continuous usage of modern managerial tools, such as a human resource information system (HRIS and electronic recruitment (ER. Human resources have been recognised as curtail resources and the main source of a competitive advantage in creation of successful business performance. In order to attract and select the top employees, companies use quality information software for attracting internal ones, and electronic recruitment for attracting the best possible external candidates. The main aim of this paper is to research the level of the usage of HRIS and ER within medium-size and large Croatian companies. Moreover, the additional aim of this paper is to evaluate the relationship among the usage of these modern managerial tools and the overall success of human resource management within these companies. For the purpose of this paper, primary and secondary research has been conducted in order to reveal the level of the usage of HRIS and ER as well as the overall success of human resource management in Croatian companies. The companies’ classification (HRIS and ER is done by using the non-hierarchical k-means cluster method as well as the nonparametric Kruskal Wallis test. Further, the companies are ranked by the multicriteria PROMETHEE method. Relevant nonparametric tests are used for testing the overall companies’ HRM. Finally, binary logistic regression is estimated, relating binary variable HRM and HRIS development. After detailed research, it can be concluded that large Croatian companies apply HRIS in majority (with a positive relation to HRM performance, but still require certain degrees of its development.

  2. QR Codes as Finding Aides: Linking Electronic and Print Library Resources

    Science.gov (United States)

    Kane, Danielle; Schneidewind, Jeff

    2011-01-01

    As part of a focused, methodical, and evaluative approach to emerging technologies, QR codes are one of many new technologies being used by the UC Irvine Libraries. QR codes provide simple connections between print and virtual resources. In summer 2010, a small task force began to investigate how QR codes could be used to provide information and…

  3. Supporting Learning and Information Sharing in Natural Resource Management with Technologies for Electronic Documents

    Science.gov (United States)

    Alem, Leila; McLean, Alistair

    2005-01-01

    Community participation is central to achieving sustainable natural resource management. A prerequisite to informed participation is that community and stakeholder groups have access to different knowledge sources, are more closely attuned to the different issues and viewpoints, and are sufficiently equipped to understand and maybe resolve complex…

  4. MendelWeb: An Electronic Science/Math/History Resource for the WWW.

    Science.gov (United States)

    Blumberg, Roger B.

    This paper describes a hypermedia resource, called MendelWeb that integrates elementary biology, discrete mathematics, and the history of science. MendelWeb is constructed from Gregor Menders 1865 paper, "Experiments in Plant Hybridization". An English translation of Mendel's paper, which is considered to mark the birth of classical and…

  5. Electronic Resources in a Next-Generation Catalog: The Case of WorldCat Local

    Science.gov (United States)

    Shadle, Steve

    2009-01-01

    In April 2007, the University of Washington Libraries debuted WorldCat Local (WCL), a localized version of the WorldCat database that interoperates with a library's integrated library system and fulfillment services to provide a single-search interface for a library's physical and electronic content. This brief will describe how WCL incorporates a…

  6. Survey of the use of electronic information resources by students in ...

    African Journals Online (AJOL)

    For libraries to continue to lead in this industry generally and academic libraries in particular, deliberate effort must be made to bring the IT education to every potential user of the libraries. This however must be done based on available data. This is what this study sought to provide- a survey of the use of electronic ...

  7. Bringing Up Gopher: Access to Local & Remote Electronic Resources for University Library Users.

    Science.gov (United States)

    Brown, Melvin Marlo; And Others

    Some of the administrative and organizational issues in creating a gopher, specifically a library gopher for university libraries, are discussed. In 1993 the Electronic Collections Task Force of the New Mexico State University library administration began to develop a library-based gopher system that would enable users to have unlimited access to…

  8. Eavesdropping on Electronic Guidebooks: Observing Learning Resources in Shared Listening Environments.

    Science.gov (United States)

    Woodruff, Allison; Aoki, Paul M.; Grinter, Rebecca E.; Hurst, Amy; Szymanski, Margaret H.; Thornton, James D.

    This paper describes an electronic guidebook, "Sotto Voce," that enables visitors to share audio information by eavesdropping on each others guidebook activity. The first section discusses the design and implementation of the guidebook device, key aspects of its user interface, the design goals for the audio environment, the eavesdropping…

  9. Data Resource Profile: Cardiovascular disease research using linked bespoke studies and electronic health records (CALIBER)

    Science.gov (United States)

    Denaxas, Spiros C; George, Julie; Herrett, Emily; Shah, Anoop D; Kalra, Dipak; Hingorani, Aroon D; Kivimaki, Mika; Timmis, Adam D; Smeeth, Liam; Hemingway, Harry

    2012-01-01

    The goal of cardiovascular disease (CVD) research using linked bespoke studies and electronic health records (CALIBER) is to provide evidence to inform health care and public health policy for CVDs across different stages of translation, from discovery, through evaluation in trials to implementation, where linkages to electronic health records provide new scientific opportunities. The initial approach of the CALIBER programme is characterized as follows: (i) Linkages of multiple electronic heath record sources: examples include linkages between the longitudinal primary care data from the Clinical Practice Research Datalink, the national registry of acute coronary syndromes (Myocardial Ischaemia National Audit Project), hospitalization and procedure data from Hospital Episode Statistics and cause-specific mortality and social deprivation data from the Office of National Statistics. Current cohort analyses involve a million people in initially healthy populations and disease registries with ∼105 patients. (ii) Linkages of bespoke investigator-led cohort studies (e.g. UK Biobank) to registry data (e.g. Myocardial Ischaemia National Audit Project), providing new means of ascertaining, validating and phenotyping disease. (iii) A common data model in which routine electronic health record data are made research ready, and sharable, by defining and curating with meta-data >300 variables (categorical, continuous, event) on risk factors, CVDs and non-cardiovascular comorbidities. (iv) Transparency: all CALIBER studies have an analytic protocol registered in the public domain, and data are available (safe haven model) for use subject to approvals. For more information, e-mail s.denaxas@ucl.ac.uk PMID:23220717

  10. Resource-efficient conception of waste electrical and electronic equipment collection groups

    OpenAIRE

    Gries, Nadja von; Wilts, Claas Henning

    2014-01-01

    Critical metals are in great demand by the electrical and electronics industry, so waste electrical and eletronic equipment represents a significant source of secondary raw materials. Owing to low recycling rates and the concomitant supply risks associated with critical metals, the closure of the material cycles is highly relevant to the German economy. Losses of these metals occur from collection until their material recovery, along the entire disposal chain of waste electrical and electroni...

  11. Preference and Use of Electronic Information and Resources by Blind/Visually Impaired in NCR Libraries in India

    Directory of Open Access Journals (Sweden)

    Shailendra Kumar

    2013-06-01

    Full Text Available This paper aims to determine the preference and use of electronic information and resources by blind/visually impaired users in the leading National Capital Region (NCR libraries of India. Survey methodology has been used as the basic research tool for data collection with the help of questionnaires. The 125 in total users surveyed in all the five libraries were selected randomly on the basis of willingness of the users with experience of working in digital environments to participate in the survey. The survey results were tabulated and analyzed with descriptive statistics methods using Excel software and 'Stata version 11'. The findings reveal that ICT have a positive impact in the lives of people with disabilities as it helps them to work independently and increases the level of confidence among them. The Internet is the most preferred medium of access to information among the majority of blind/visually impaired users. The 'Complexity of content available on the net' is found as the major challenge faced during Internet use by blind users of NCR libraries. 'Audio books on CDs/DVDs and DAISY books' are the most preferred electronic resources among the majority of blind/visually impaired users. This study will help the library professionals and organizations/institutions serving people with disabilities to develop effective library services for blind/visually impaired users in the digital environment on the basis of findings on information usage behavior in the study.

  12. An Exploratory study on the use of LibAnswers to Resolve, Track and Monitor Electronic Resources Issues: The KAUST Library experience

    KAUST Repository

    Ramli, Rindra M.

    2017-05-03

    An Exploratory study on KAUST library use of LibAnswers in resolving electronic resources questions received in LibAnswers. It describes the findings of the questions received in LibAnswers. The author made suggestions based on the findings to improve the reference services in responding to e-resources questions.

  13. Internet and electronic resources for inflammatory bowel disease: a primer for providers and patients.

    Science.gov (United States)

    Fortinsky, Kyle J; Fournier, Marc R; Benchimol, Eric I

    2012-06-01

    Patients with inflammatory bowel disease (IBD) are increasingly turning to the Internet to research their condition and engage in discourse on their experiences. This has resulted in new dynamics in the relationship between providers and their patients, with misinformation and advertising potentially presenting barriers to the cooperative patient-provider partnership. This article addresses important issues of online IBD-related health information and social media activity, such as quality, reliability, objectivity, and privacy. We reviewed the medical literature on the quality of online information provided to IBD patients, and summarized the most commonly accessed Websites related to IBD. We also assessed the activity on popular social media sites (such as Facebook, Twitter, and YouTube), and evaluated currently available applications for use by IBD patients and providers on mobile phones and tablets. Through our review of the literature and currently available resources, we developed a list of recommended online resources to strengthen patient participation in their care by providing reliable, comprehensive educational material. Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.

  14. Granulometric composition study of mineral resources using opto-electronic devices and Elsieve software system

    OpenAIRE

    Kaminski Stanislaw; Kaminski Piotr; Kaminska Dorota; Trzcinski Jerzy

    2016-01-01

    The use of mechanical sieves has a great impact on measurement results because occurrence of anisometric particles causes undercounting the average size. Such errors can be avoided by using opto-electronic measuring devices that enable measurement of particles from 10 μm up to a few dozen millimetres in size. The results of measurement of each particle size fraction are summed up proportionally to its weight with the use of Elsieve software system and for every type of material particle-size ...

  15. Microbial biosynthesis of nontoxic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Swarup, E-mail: swaruproy@klyuniv.ac.in [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Das, Tapan Kumar [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Maiti, Guru Prasad [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India); Department of Anesthesiology, Texas Tech University Health science Center, 3601 4th Street, Lubbock, TX 79430 (United States); Basu, Utpal [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India)

    2016-01-15

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  16. Microbial biosynthesis of nontoxic gold nanoparticles

    International Nuclear Information System (INIS)

    Roy, Swarup; Das, Tapan Kumar; Maiti, Guru Prasad; Basu, Utpal

    2016-01-01

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  17. Granulometric composition study of mineral resources using opto-electronic devices and Elsieve software system

    Directory of Open Access Journals (Sweden)

    Kaminski Stanislaw

    2016-01-01

    Full Text Available The use of mechanical sieves has a great impact on measurement results because occurrence of anisometric particles causes undercounting the average size. Such errors can be avoided by using opto-electronic measuring devices that enable measurement of particles from 10 μm up to a few dozen millimetres in size. The results of measurement of each particle size fraction are summed up proportionally to its weight with the use of Elsieve software system and for every type of material particle-size distribution can be obtained. The software allows further statistical interpretation of the results. Beam of infrared radiation identifies size of particles and counts them precisely. Every particle is represented by an electronic impulse proportional to its size. Measurement of particles in aqueous suspension that replaces the hydrometer method can be carried out by using the IPS L analyser (range from 0.2 to 600 μm. The IPS UA analyser (range from 0.5 to 2000 μm is designed for measurement in the air. An ultrasonic adapter enables performing measurements of moist and aggregated particles from 0.5 to 1000 μm. The construction and software system allow to determine second dimension of the particle, its shape coefficient and specific surface area. The AWK 3D analyser (range from 0.2 to 31.5 mm is devoted to measurement of various powdery materials with subsequent determination of particle shape. The AWK B analyser (range from 1 to 130 mm measures materials of thick granulation and shape of the grains. The presented method of measurement repeatedly accelerates and facilitates study of granulometric composition.

  18. [Optimization of oxytetracycline biosynthesis].

    Science.gov (United States)

    Maksimova, E A; Falkov, N N; Izmaĭlov, N N; Romanchuk, N N

    1988-06-01

    It was shown that rising of temperature up to 30 degrees C at the stage of the oxytetracycline-producing organism growth promoted acceleration of the culture growth rate and increasing of the antibiotic concentration by the 114th hour of the biosynthetic process. For the apparatus used in the study optimal aeration and agitation conditions were developed. To provide optimal parameters during biosynthesis of oxytetracycline, it was recommended to use the aeration rate of 1 v/v.min and the specific mechanical power for mixing of not less than 1 kW/m3.

  19. Biosynthesis of Rishirilide B

    Directory of Open Access Journals (Sweden)

    Philipp Schwarzer

    2018-03-01

    Full Text Available Rishirilide B was isolated from Streptomyces rishiriensis and Streptomyces bottropensis on the basis of its inhibitory activity towards alpha-2-macroglobulin. The biosynthesis of rishirilide B was investigated by feeding experiments with different 13C labelled precursors using the heterologous host Streptomyces albus J1074::cos4 containing a cosmid encoding of the gene cluster responsible for rishirilide B production. NMR spectroscopic analysis of labelled compounds demonstrate that the tricyclic backbone of rishirilide B is a polyketide synthesized from nine acetate units. One of the acetate units is decarboxylated to give a methyl group. The origin of the starter unit was determined to be isobutyrate.

  20. Electronic learning and open educational resources in the health sciences in ghana.

    Science.gov (United States)

    Adanu, Rmk; Adu-Sarkodie, Y; Opare-Sem, O; Nkyekyer, K; Donkor, P; Lawson, A; Engleberg, N C

    2010-12-01

    To determine whether a group of Ghanaian students are able to easily use electronic learning material and whether they perceive this method of learning as acceptable. The University of Ghana Medical School (UGMS) and the School of Medical Sciences (SMS), Kwame Nkrumah University of Science and Technology (KNUST) PARTICIPANTS: One hundred and fifty third year medical students at SMS and nineteen fifth year medical students at UGMS METHODS: Two e-learning materials were developed, one on the polymerase chain reaction and the other on total abdominal hysterectomy and these were distributed to selected medical students. Two weeks after the distribution of the programmes, a one-page, self-administered questionnaire was distributed to the target groups of students at the two institutions. Ninety three percent (139) of respondents at KNUST and 95% (18) at UG report having access to a computer for learning purposes. All of the UG students viewed the TAH programme; 82% (130) of the KNUST students viewed the PCR animations. All students who viewed the programmes at both institutions indicated that the e-learning pro-grammes were "more effective" in comparison to other methods of learning. Computer ownership or availability at both medical schools is sufficient to permit the distribution and viewing of e-learning materials by students and the medical students considered both programmes to be very helpful.

  1. Cardiovascular implantable electronic device function and longevity at autopsy: an underestimated resource.

    Science.gov (United States)

    Sinha, Sunil K; Crain, Barbara; Flickinger, Katie; Calkins, Hugh; Rickard, John; Cheng, Alan; Berger, Ronald; Tomaselli, Gordon; Marine, Joseph E

    2016-10-01

    The feasibility and safety of postmortem cardiovascular implantable electronic device (CIED; pacemaker or defibrillator) retrieval for reuse has been shown. To date, studies indicate a low yield of reusable postmortem CIEDs (17%-30%). The purpose of this study was to test the hypothesis that a higher rate of reusable CIEDs would be identified upon postmortem retrieval when an institutional protocol for systematic and routine acquisition, interrogation, reprogramming, and manufacturer analysis was used. Over a 6-year period, all subjects referred for autopsy underwent concomitant CIED pulse generator retrieval and enrollment in the Johns Hopkins Post-Mortem CIED Registry. CIEDs were interrogated, reprogrammed, and submitted for manufacturer analysis. In total, 84 autopsies had CIEDs (37 pacemakers, 47 implantable cardioverter-defibrillators). CIEDs were implanted 2.84 ± 2.32 years before death, with 30% implanted 60% of pacemakers and >50% of defibrillators demonstrated normal functional status with projected longevities >7 years on average. Formation of a national hospital-based "CIED donor network" would facilitate larger scale charitable efforts in underserved countries. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  2. (+)-Germacrene A Biosynthesis

    Science.gov (United States)

    de Kraker, Jan-Willem; Franssen, Maurice C.R.; de Groot, Aede; König, Wilfried A.; Bouwmeester, Harro J.

    1998-01-01

    The leaves and especially the roots of chicory (Cichorium intybus L.) contain high concentrations of bitter sesquiterpene lactones such as the guianolides lactupicrin, lactucin, and 8-deoxylactucin. Eudesmanolides and germacranolides are present in smaller amounts. Their postulated biosynthesis through the mevalonate-farnesyl diphosphate-germacradiene pathway has now been confirmed by the isolation of a (+)-germacrene A synthase from chicory roots. This sesquiterpene cyclase was purified 200-fold using a combination of anion-exchange and dye-ligand chromatography. It has a Km value of 6.6 μm, an estimated molecular mass of 54 kD, and a (broad) pH optimum around 6.7. Germacrene A, the enzymatic product, proved to be much more stable than reported in literature. Its heat-induced Cope rearrangement into (−)-β-elemene was utilized to determine its absolute configuration on an enantioselective gas chromatography column. To our knowledge, until now in sesquiterpene biosynthesis, germacrene A has only been reported as an (postulated) enzyme-bound intermediate, which, instead of being released, is subjected to additional cyclization(s) by the same enzyme that generated it from farnesyl diphosphate. However, in chicory germacrene A is released from the sesquiterpene cyclase. Apparently, subsequent oxidations and/or glucosylation of the germacrane skeleton, together with a germacrene cyclase, determine whether guaiane- or eudesmane-type sesquiterpene lactones are produced. PMID:9701594

  3. Green Supply Chain Collaboration for Fashionable Consumer Electronics Products under Third-Party Power Intervention—A Resource Dependence Perspective

    Directory of Open Access Journals (Sweden)

    Jiuh-Biing Sheu

    2014-05-01

    Full Text Available Under third-party power intervention (TPPI, which increases uncertainty in task environments, complex channel power interplays and restructuring are indispensable among green supply chain members as they move toward sustainable collaborative relationships for increased viability and competitive advantage. From the resource dependence perspective, this work presents a novel conceptual model to investigate the influence of political and social power on channel power restructuring and induced green supply chain collaboration in brander-retailer bidirectional green supply chains of fashionable consumer electronics products (FCEPs. An FCEP refers to the consumer electronics product (e.g., personal computers, mobile phones, computer notebooks, and game consoles with the features of a well-known brand associated, a short product lifecycle, timely and fashionable design fit for market trends, and quick responsiveness to the variations of market demands. The proposed model is tested empirically using questionnaire data obtained from retailers in the FCEP brander-retailer distribution channels. Analytical results reveal that as an extension of political and social power, TPPI positively affects the reciprocal interdependence of dyadic members and reduces power asymmetry, thereby enhancing the collaborative relationship of dyadic members and leading to improved green supply chain performance. Therein, reciprocal interdependence underlying collaborative relationship is the key to reducing the external environmental uncertainties in the TPPI context.

  4. Electronic medical record data to identify variables associated with a fibromyalgia diagnosis: importance of health care resource utilization

    Directory of Open Access Journals (Sweden)

    Masters ET

    2015-03-01

    Full Text Available Elizabeth T Masters,1 Jack Mardekian,1 Birol Emir,1 Andrew Clair,1 Max Kuhn,2 Stuart L Silverman,31Pfizer, Inc., New York, NY, 2Pfizer, Inc., Groton, CT, 3Cedars-Sinai Medical Center, Los Angeles, CA, USABackground: Diagnosis of fibromyalgia (FM is often challenging. Identifying factors associated with an FM diagnosis may guide health care providers in implementing appropriate diagnostic and management strategies.Methods: This retrospective study used the de-identified Humedica electronic medical record (EMR database to identify variables associated with an FM diagnosis. Cases (n=4,296 were subjects ≥18 years old with ≥2 International Classification of Diseases, Ninth Revision (ICD-9 codes for FM (729.1 ≥30 days apart during 2012, associated with an integrated delivery network, with ≥1 encounter with a health care provider in 2011 and 2012. Controls without FM (no-FM; n=583,665 did not have the ICD-9 codes for FM. Demographic, clinical, and health care resource utilization variables were extracted from structured EMR data. Univariate analysis identified variables showing significant differences between the cohorts based on odds ratios (ORs.Results: Consistent with FM epidemiology, FM subjects were predominantly female (78.7% vs 64.5%; P<0.0001 and slightly older (mean age 53.3 vs 52.7 years; P=0.0318. Relative to the no-FM cohort, the FM cohort was characterized by a higher prevalence of nearly all evaluated comorbidities; the ORs suggested a higher likelihood of an FM diagnosis (P<0.0001, especially for musculoskeletal and neuropathic pain conditions (OR 3.1 for each condition. Variables potentially associated with an FM diagnosis included higher levels of use of specific health care resources including emergency-room visits, outpatient visits, hospitalizations, and medications. Units used per subject for emergency-room visits, outpatient visits, hospitalizations, and medications were also significantly higher in the FM cohort (P<0

  5. Biosynthesis of Gold Nanoparticles Using Pseudomonas Aeruginosa

    International Nuclear Information System (INIS)

    Abd El-Aziz, M.; Badr, Y.; Mahmoud, M. A.

    2007-01-01

    Pseudomonas aeruginosa were used for extracellular biosynthesis of gold nanoparticles (Au NPs). Consequently, Au NPs were formed due to reduction of gold ion by bacterial cell supernatant of P. aeruginos ATCC 90271, P. aeruginos (2) and P. aeruginos (1). The UV-Vis. and fluorescence spectra of the bacterial as well as chemical prepared Au NPs were recorded. Transmission electron microscopy (TEM) micrograph showed the formation of well-dispersed gold nanoparticles in the range of 15-30 nm. The process of reduction being extracellular and may lead to the development of an easy bioprocess for synthesis of Au NPs

  6. Innovative direct energy conversion systems using electronic adiabatic processes of electron fluid in solid conductors: new plants of electrical power and hydrogen gas resources without environmental pollutions

    International Nuclear Information System (INIS)

    Kondoh, Y.; Kondo, M.; Shimoda, K.; Takahashi, T.

    2001-07-01

    It is shown that using a novel recycling process of the environmental thermal energy, innovative permanent auto-working direct energy converter systems (PA-DEC systems) from the environmental thermal to electrical and/or chemical potential (TE/CP) energies, abbreviated as PA-TE/CP-DEC systems, can be used for new auto-working electrical power plants and the plants of the compressible and conveyable hydrogen gas resources at various regions in the whole world, with contributions to the world peace and the economical development in the south part of the world. It is shown that the same physical mechanism by free electrons and electrical potential determined by temperature in conductors, which include semiconductors, leads to the Peltier effect and the Seebeck one. It is experimentally clarified that the long distance separation between two π type elements of the heat absorption (HAS) and the production one (HPS) of the Peltier effect circuit system or between the higher temperature side (HTS) and the lower one (LTS) of the Seebeck effect circuit one does not change in the whole for the both effects. By using present systems, we do not need to use petrified fuels such as coals, oils, and natural gases in order to decrease the greenhouse effect by the CO 2 surrounding the earth. Furthermore, we do not need plats of nuclear fissions that left radiating wastes, i.e., with no environmental pollutions. The PA-TE/CP-DEC systems can be applicable for several km scale systems to the micro ones, such as the plants of the electrical power, the compact transportable hydrogen gas resources, a large heat energy container, which can be settled at far place from thermal energy absorbing area, the refrigerators, the air conditioners, home electrical apparatuses, and further the computer elements. It is shown that the simplest PA-TE/CP-DEC system can be established by using only the Seebeck effect components and the resolving water ones. It is clarified that the externally applied

  7. Development of an electronic medical record based alert for risk of HIV treatment failure in a low-resource setting.

    Directory of Open Access Journals (Sweden)

    Nancy Puttkammer

    Full Text Available The adoption of electronic medical record systems in resource-limited settings can help clinicians monitor patients' adherence to HIV antiretroviral therapy (ART and identify patients at risk of future ART failure, allowing resources to be targeted to those most at risk.Among adult patients enrolled on ART from 2005-2013 at two large, public-sector hospitals in Haiti, ART failure was assessed after 6-12 months on treatment, based on the World Health Organization's immunologic and clinical criteria. We identified models for predicting ART failure based on ART adherence measures and other patient characteristics. We assessed performance of candidate models using area under the receiver operating curve, and validated results using a randomly-split data sample. The selected prediction model was used to generate a risk score, and its ability to differentiate ART failure risk over a 42-month follow-up period was tested using stratified Kaplan Meier survival curves.Among 923 patients with CD4 results available during the period 6-12 months after ART initiation, 196 (21.2% met ART failure criteria. The pharmacy-based proportion of days covered (PDC measure performed best among five possible ART adherence measures at predicting ART failure. Average PDC during the first 6 months on ART was 79.0% among cases of ART failure and 88.6% among cases of non-failure (p<0.01. When additional information including sex, baseline CD4, and duration of enrollment in HIV care prior to ART initiation were added to PDC, the risk score differentiated between those who did and did not meet failure criteria over 42 months following ART initiation.Pharmacy data are most useful for new ART adherence alerts within iSanté. Such alerts offer potential to help clinicians identify patients at high risk of ART failure so that they can be targeted with adherence support interventions, before ART failure occurs.

  8. Consumer reports [electronic resource

    National Research Council Canada - National Science Library

    1942-01-01

    ... only. A limited number of selected reports, advice on product selection and safety alerts are freely available, as are a five year listing of product recalls, a listing of major consumer product...

  9. Electronic Commerce Resource Centers

    National Research Council Canada - National Science Library

    Caprio, Kimberley

    1997-01-01

    ... No. 5AB-0052, "Audit of the Management and Administration of Research Projects Funded by the Defense Advanced Research Projects Agency," will discuss the adequacy of the Defense Advanced Research...

  10. Electronic Information Resources (EIR Adoption in Private University Libraries: The Moderating Effect of Productivity and Relative Advantage on Perceived Usefulness

    Directory of Open Access Journals (Sweden)

    Izuagbe, Roland

    2016-03-01

    Full Text Available The study tested a hybrid model with constructs drawn from the Technology Acceptance Model (TAM and Diffusion of Innovation (DOI theory in order to examine the moderating effect of productivity and relative advantage (RA on perceived usefulness (PU vis-à-vis electronic information resources (EIR adoption in private university libraries in Ogun and Osun States of Nigeria. The descriptive research design was adopted in the study. The population consisted of 61 (55.0% librarians and 50 (45.0% library officers (totaling 116—100% in Babcock University, Bells University, Covenant University, Bowen University, Oduduwa University, and Redeemer's University. Purposive sampling procedure was adopted after which total enumeration was used since the total population is small. The questionnaire was used for data collection. Of the 116 copies of the questionnaire administered, 111 (95.7% were found usable. The instrument was structured based on a 4-point Likert agreement scale of Strongly Agree, Agree, Disagree, and Strongly Disagree. Data were analyzed using descriptive statistics like tables of frequency counts and percentage. The findings revealed that productivity and relative advantage are significant moderators of perceived usefulness of EIR adoption in private university libraries in Ogun and Osun States, Nigeria.

  11. Serine biosynthesis and transport defects.

    Science.gov (United States)

    El-Hattab, Ayman W

    2016-07-01

    l-serine is a non-essential amino acid that is biosynthesized via the enzymes phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Besides its role in protein synthesis, l-serine is a potent neurotrophic factor and a precursor of a number of essential compounds including phosphatidylserine, sphingomyelin, glycine, and d-serine. Serine biosynthesis defects result from impairments of PGDH, PSAT, or PSP leading to systemic serine deficiency. Serine biosynthesis defects present in a broad phenotypic spectrum that includes, at the severe end, Neu-Laxova syndrome, a lethal multiple congenital anomaly disease, intermediately, infantile serine biosynthesis defects with severe neurological manifestations and growth deficiency, and at the mild end, the childhood disease with intellectual disability. A serine transport defect resulting from deficiency of the ASCT1, the main transporter for serine in the central nervous system, has been recently described in children with neurological manifestations that overlap with those observed in serine biosynthesis defects. l-serine therapy may be beneficial in preventing or ameliorating symptoms in serine biosynthesis and transport defects, if started before neurological damage occurs. Herein, we review serine metabolism and transport, the clinical, biochemical, and molecular aspects of serine biosynthesis and transport defects, the mechanisms of these diseases, and the potential role of serine therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. The BRIGHTEN Program: Implementation and Evaluation of a Program to Bridge Resources of an Interdisciplinary Geriatric Health Team via Electronic Networking

    Science.gov (United States)

    Emery, Erin E.; Lapidos, Stan; Eisenstein, Amy R.; Ivan, Iulia I.; Golden, Robyn L.

    2012-01-01

    Purpose: To demonstrate the feasibility of the BRIGHTEN Program (Bridging Resources of an Interdisciplinary Geriatric Health Team via Electronic Networking), an interdisciplinary team intervention for assessing and treating older adults for depression in outpatient primary and specialty medical clinics. The BRIGHTEN team collaborates "virtually"…

  13. The module of methodical support in system of electronic educational resources as the innovative element of the modern maintenance of formation

    Directory of Open Access Journals (Sweden)

    Ольга Николаевна Крылова

    2009-06-01

    Full Text Available The article introduces some results of research, which were devoted to evaluation of tearches' mobility to introduce innovations in the contents of education. The author considers innovative potential of modules of the methodical support for system of electronic educational resources.

  14. Charting a Course through CORAL: Texas A&M University Libraries' Experience Implementing an Open-Source Electronic Resources Management System

    Science.gov (United States)

    Hartnett, Eric; Beh, Eugenia; Resnick, Taryn; Ugaz, Ana; Tabacaru, Simona

    2013-01-01

    In 2010, after two previous unsuccessful attempts at electronic resources management system (ERMS) implementation, Texas A&M University (TAMU) Libraries set out once again to find an ERMS that would fit its needs. After surveying the field, TAMU Libraries selected the University of Notre Dame Hesburgh Libraries-developed, open-source ERMS,…

  15. 圖書館事業專欄/Marketing of Electronic Information Resources: A Case of The J.D. Rockefeller Research Library, Egerton University/Nerisa Kamar

    OpenAIRE

    Nerisa Kamar

    2008-01-01

    This paper gives a brief overview of electronic information resources and services offered by The J.D. Rockefeller Research Library at Egerton University and the marketing of these resources. The paper examines the various reasons for marketing electronic information resources, with emphasis on the various, and illustrates marketing strategies used by J.D Rockefeller Research library towards effective utilization of the available resources in supporting research, teaching and learnin...

  16. Carotenoid Biosynthesis in Fusarium

    Directory of Open Access Journals (Sweden)

    Javier Avalos

    2017-07-01

    Full Text Available Many fungi of the genus Fusarium stand out for the complexity of their secondary metabolism. Individual species may differ in their metabolic capacities, but they usually share the ability to synthesize carotenoids, a family of hydrophobic terpenoid pigments widely distributed in nature. Early studies on carotenoid biosynthesis in Fusarium aquaeductuum have been recently extended in Fusarium fujikuroi and Fusarium oxysporum, well-known biotechnological and phytopathogenic models, respectively. The major Fusarium carotenoid is neurosporaxanthin, a carboxylic xanthophyll synthesized from geranylgeranyl pyrophosphate through the activity of four enzymes, encoded by the genes carRA, carB, carT and carD. These fungi produce also minor amounts of β-carotene, which may be cleaved by the CarX oxygenase to produce retinal, the rhodopsin’s chromophore. The genes needed to produce retinal are organized in a gene cluster with a rhodopsin gene, while other carotenoid genes are not linked. In the investigated Fusarium species, the synthesis of carotenoids is induced by light through the transcriptional induction of the structural genes. In some species, deep-pigmented mutants with up-regulated expression of these genes are affected in the regulatory gene carS. The molecular mechanisms underlying the control by light and by the CarS protein are currently under investigation.

  17. Biosynthesis of Tetrahydroisoquinoline Antibiotics.

    Science.gov (United States)

    Tang, Gong-Li; Tang, Man-Cheng; Song, Li-Qiang; Zhang, Yue

    2016-01-01

    The tetrahydroisoquinoline (THIQ) alkaloids are naturally occurring antibiotics isolated from a variety of microorganisms and marine invertebrates. This family of natural products exhibit broad spectrum antimicrobial and strong antitumor activities, and the potency of clinical application has been validated by the marketing of ecteinascidin 743 (ET-743) as anticancer drug. In the past 20 years, the biosynthetic gene cluster of six THIQ antibiotics has been characterized including saframycin Mx1 from Myxococcus xanthus, safracin-B from Pseudomonas fluorescens, saframycin A, naphthyridinomycin, and quinocarcin from Streptomyces, as well as ET-743 from Ecteinascidia turbinata. This review gives a brief summary of the current status in understanding the molecular logic for the biosynthesis of these natural products, which provides new insights on the biosynthetic machinery involved in the nonribosomal peptide synthetase system. The proposal of the THIQ biosynthetic pathway not only shows nature's route to generate such complex molecules, but also set the stage to develop a different process for production of ET-743 by synthetic biology.

  18. Stereoselectivity in Polyphenol Biosynthesis

    Science.gov (United States)

    Lewis, Norman G.; Davin, Laurence B.

    1992-01-01

    Stereoselectivity plays an important role in the late stages of phenyl-propanoid metabolism, affording lignins, lignans, and neolignans. Stereoselectivity is manifested during monolignol (glucoside) synthesis, e.g., where the geometry (E or Z) of the pendant double bond affects the specificity of UDPG:coniferyl alcohol glucosyltransferases in different species. Such findings are viewed to have important ramifications in monolignol transport and storage processes, with roles for both E- and Z-monolignols and their glucosides in lignin/lignan biosynthesis being envisaged. Stereoselectivity is also of great importance in enantiose-lective enzymatic processes affording optically active lignans. Thus, cell-free extracts from Forsythia species were demonstrated to synthesize the enantiomerically pure lignans, (-)-secoisolariciresinol, and (-)-pinoresinol, when NAD(P)H, H2O2 and E-coniferyl alcohol were added. Progress toward elucidating the enzymatic steps involved in such highly stereoselective processes is discussed. Also described are preliminary studies aimed at developing methodologies to determine the subcellular location of late-stage phenylpropanoid metabolites (e.g., coniferyl alcohol) and key enzymes thereof, in intact tissue or cells. This knowledge is essential if questions regarding lignin and lignan tissue specificity and regulation of these processes are to be deciphered.

  19. Glycolipid biosynthesis in cyanobacteria

    International Nuclear Information System (INIS)

    Van Dusen, W.J.; Jaworski, J.G.

    1987-01-01

    The biosynthesis of monogalactosyldiacyl-glycerol (MGDG) was studied in five different cyanobacteria. Previous work has shown Anabaena variabilis to synthesize both MGDG and monoglucosyl-diacylglycerol (MG1cDG) with MG1cDG being the precursor of MGDG. They have examined four other cyanobacteria to determine if a similar relationship exists. The cyanobacteria studied were Anabaena variabilis, Chlorogloeopsis sp., Schizothrix calcicola, Anacystis nidulans, and Anacystis marina. Each were grown in liquid culture and lipids were labeled with 14 C]CO 2 for 20 min., 1.0 hr, 1.0 hr + 10 hr chase. Glycolipids were analyzed by initial separation of MGDG and MG1cDG by TLC followed by further analysis by HPLC. Complete separation of molecular species was obtained isocratically on an ODS column. All of the cyanobacteria labeled 16-C and 18-C fatty acids except for A. marina which labeled only 14-C and 16-C fatty acids. Desaturation of the fatty acids could be observed in the 1.0 hr and chase experiments. All were capable of labeling both MG1cDG and MGDG with the precursor-product relationship being observed. There does not appear to be a direct relationship between the epimerization of the sugar moiety and fatty acid desaturation

  20. Isoprenoid Biosynthesis Inhibitors Targeting Bacterial Cell Growth.

    Science.gov (United States)

    Desai, Janish; Wang, Yang; Wang, Ke; Malwal, Satish R; Oldfield, Eric

    2016-10-06

    We synthesized potential inhibitors of farnesyl diphosphate synthase (FPPS), undecaprenyl diphosphate synthase (UPPS), or undecaprenyl diphosphate phosphatase (UPPP), and tested them in bacterial cell growth and enzyme inhibition assays. The most active compounds were found to be bisphosphonates with electron-withdrawing aryl-alkyl side chains which inhibited the growth of Gram-negative bacteria (Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa) at ∼1-4 μg mL -1 levels. They were found to be potent inhibitors of FPPS; cell growth was partially "rescued" by the addition of farnesol or overexpression of FPPS, and there was synergistic activity with known isoprenoid biosynthesis pathway inhibitors. Lipophilic hydroxyalkyl phosphonic acids inhibited UPPS and UPPP at micromolar levels; they were active (∼2-6 μg mL -1 ) against Gram-positive but not Gram-negative organisms, and again exhibited synergistic activity with cell wall biosynthesis inhibitors, but only indifferent effects with other inhibitors. The results are of interest because they describe novel inhibitors of FPPS, UPPS, and UPPP with cell growth inhibitory activities as low as ∼1-2 μg mL -1 . © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Auxin biosynthesis and storage forms

    Science.gov (United States)

    Strader, Lucia C.

    2013-01-01

    The plant hormone auxin drives plant growth and morphogenesis. The levels and distribution of the active auxin indole-3-acetic acid (IAA) are tightly controlled through synthesis, inactivation, and transport. Many auxin precursors and modified auxin forms, used to regulate auxin homeostasis, have been identified; however, very little is known about the integration of multiple auxin biosynthesis and inactivation pathways. This review discusses the many ways auxin levels are regulated through biosynthesis, storage forms, and inactivation, and the potential roles modified auxins play in regulating the bioactive pool of auxin to affect plant growth and development. PMID:23580748

  2. Hypericin: chemical synthesis and biosynthesis.

    Science.gov (United States)

    Huang, Lin-Fang; Wang, Zeng-Hui; Chen, Shi-Lin

    2014-02-01

    Hypericin is one of the most important phenanthoperylene quinones extracted mainly from plants of the genus Hypericum belonging to the sections Euhypericum and Campylosporus of Keller's classification. Widespread attention to the antiviral and anti-tumor properties of hypericin has spurred investigations of the chemical synthesis and biosynthesis of this unique compound. However, the synthetic strategies are challenging for organic and biological chemists. In this review, specific significant advances in total synthesis, semi-synthesis, and biosynthesis in the past decades are summarized. Copyright © 2014 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  3. The electronic Trauma Health Record: design and usability of a novel tablet-based tool for trauma care and injury surveillance in low resource settings.

    Science.gov (United States)

    Zargaran, Eiman; Schuurman, Nadine; Nicol, Andrew J; Matzopoulos, Richard; Cinnamon, Jonathan; Taulu, Tracey; Ricker, Britta; Garbutt Brown, David Ross; Navsaria, Pradeep; Hameed, S Morad

    2014-01-01

    Ninety percent of global trauma deaths occur in under-resourced or remote environments, with little or no capacity for injury surveillance. We hypothesized that emerging electronic and web-based technologies could enable design of a tablet-based application, the electronic Trauma Health Record (eTHR), used by front-line clinicians to inform trauma care and acquire injury surveillance data for injury control and health policy development. The study was conducted in 3 phases: 1. Design of an electronic application capable of supporting clinical care and injury surveillance; 2. Preliminary feasibility testing of eTHR in a low-resource, high-volume trauma center; and 3. Qualitative usability testing with 22 trauma clinicians from a spectrum of high- and low-resource and urban and remote settings including Vancouver General Hospital, Whitehorse General Hospital, British Columbia Mobile Medical Unit, and Groote Schuur Hospital in Cape Town, South Africa. The eTHR was designed with 3 key sections (admission note, operative note, discharge summary), and 3 key capabilities (clinical checklist creation, injury severity scoring, wireless data transfer to electronic registries). Clinician-driven registry data collection proved to be feasible, with some limitations, in a busy South African trauma center. In pilot testing at a level I trauma center in Cape Town, use of eTHR as a clinical tool allowed for creation of a real-time, self-populating trauma database. Usability assessments with traumatologists in various settings revealed the need for unique eTHR adaptations according to environments of intended use. In all settings, eTHR was found to be user-friendly and have ready appeal for frontline clinicians. The eTHR has potential to be used as an electronic medical record, guiding clinical care while providing data for injury surveillance, without significantly hindering hospital workflow in various health-care settings. Copyright © 2014 American College of Surgeons. Published

  4. (vitamin B1) biosynthesis genes

    African Journals Online (AJOL)

    In this study, the gene transcripts of first two enzymes in thiamine biosynthesis pathway, THIC and THI1/THI4 were identified and amplified from oil palm tissues. Primers were designed based on sequence comparison of the genes from Arabidopsis thaliana, Zea mays, Oryza sativa and Alnus glutinosa. Oil palm's responses ...

  5. (-)-Menthol biosynthesis and molecular genetics

    Science.gov (United States)

    Croteau, Rodney B.; Davis, Edward M.; Ringer, Kerry L.; Wildung, Mark R.

    2005-12-01

    (-)-Menthol is the most familiar of the monoterpenes as both a pure natural product and as the principal and characteristic constituent of the essential oil of peppermint ( Mentha x piperita). In this paper, we review the biosynthesis and molecular genetics of (-)-menthol production in peppermint. In Mentha species, essential oil biosynthesis and storage is restricted to the peltate glandular trichomes (oil glands) on the aerial surfaces of the plant. A mechanical method for the isolation of metabolically functional oil glands, has provided a system for precursor feeding studies to elucidate pathway steps, as well as a highly enriched source of the relevant biosynthetic enzymes and of their corresponding transcripts with which cDNA libraries have been constructed to permit cloning and characterization of key structural genes. The biosynthesis of (-)-menthol from primary metabolism requires eight enzymatic steps, and involves the formation and subsequent cyclization of the universal monoterpene precursor geranyl diphosphate to the parent olefin (-)-(4 S)-limonene as the first committed reaction of the sequence. Following hydroxylation at C3, a series of four redox transformations and an isomerization occur in a general “allylic oxidation-conjugate reduction” scheme that installs three chiral centers on the substituted cyclohexanoid ring to yield (-)-(1 R, 3 R, 4 S)-menthol. The properties of each enzyme and gene of menthol biosynthesis are described, as are their probable evolutionary origins in primary metabolism. The organization of menthol biosynthesis is complex in involving four subcellular compartments, and regulation of the pathway appears to reside largely at the level of gene expression. Genetic engineering to up-regulate a flux-limiting step and down-regulate a side route reaction has led to improvement in the composition and yield of peppermint oil.

  6. Barriers to electronic access and delivery of educational information in resource constrained public schools: a case of Greater Tubatse Municipality

    CSIR Research Space (South Africa)

    Pholotho, T

    2016-05-01

    Full Text Available Information and Communication Technologies (ICTs) are capable of expanding access to quality education, educational resources and provide teachers with new skills. Nevertheless, a majority of rural public schools have limited ICTs, mainly due...

  7. Electronic Grey Literature in Accelerator Science and Its Allied Subjects : Selected Web Resources for Scientists and Engineers

    CERN Document Server

    Rajendiran, P

    2006-01-01

    Grey literature Web resources in the field of accelerator science and its allied subjects are collected for the scientists and engineers of RRCAT (Raja Ramanna Centre for Advanced Technology). For definition purposes the different types of grey literature are described. The Web resources collected and compiled in this article (with an overview and link for each) specifically focus on technical reports, preprints or e-prints, which meet the main information needs of RRCAT users.

  8. [Biosynthesis of adipic acid].

    Science.gov (United States)

    Han, Li; Chen, Wujiu; Yuan, Fei; Zhang, Yuanyuan; Wang, Qinhong; Ma, Yanhe

    2013-10-01

    Adipic acid is a six-carbon dicarboxylic acid, mainly for the production of polymers such as nylon, chemical fiber and engineering plastics. Its annual demand is close to 3 million tons worldwide. Currently, the industrial production of adipic acid is based on the oxidation of aromatics from non-renewable petroleum resources by chemo-catalytic processes. It is heavily polluted and unsustainable, and the possible alternative method for adipic acid production should be developed. In the past years, with the development of synthetic biology and metabolic engineering, green and clean biotechnological methods for adipic acid production attracted more attention. In this study, the research advances of adipic acid and its precursor production are reviewed, followed by addressing the perspective of the possible new pathways for adipic acid production.

  9. Recombinatorial biosynthesis of polyketides.

    Science.gov (United States)

    Starcevic, Antonio; Wolf, Kerstin; Diminic, Janko; Zucko, Jurica; Ruzic, Ida Trninic; Long, Paul F; Hranueli, Daslav; Cullum, John

    2012-03-01

    Modular polyketide synthases (PKSs) from Streptomyces and related genera of bacteria produce many important pharmaceuticals. A program called CompGen was developed to carry out in silico homologous recombination between gene clusters encoding PKSs and determine whether recombinants have cluster architectures compatible with the production of polyketides. The chemical structure of recombinant polyketides was also predicted. In silico recombination was carried out for 47 well-characterised clusters. The predicted recombinants would produce 11,796 different polyketide structures. The molecular weights and average degree of reduction of the chemical structures are dispersed around the parental structures indicating that they are likely to include pharmaceutically interesting compounds. The details of the recombinants and the chemical structures were entered in a database called r-CSDB. The virtual compound library is a useful resource for computer-aided drug design and chemoinformatics strategies for finding pharmaceutically relevant chemical entities. A strategy to construct recombinant Streptomyces strains to produce these polyketides is described and the critical steps of mobilizing large biosynthetic clusters and producing new linear cloning vectors are illustrated by experimental data.

  10. Web Accessibility Issues for Higher & Further Education. EDNER (Formative Evaluation of the Distributed National Electronic Resource) Project. Issues Paper.

    Science.gov (United States)

    Manchester Metropolitan Univ. (England).

    This issues paper, sixth in a series of eight, is intended to distill formative evaluation questions on topics that are central to the development of the higher and further education information environment in the United Kingdom. In undertaking formative evaluation studies, the Formative Evaluation of the Distributed National Electronic Resource…

  11. Analyzing the Academic Research Trends by Using University Digital Resources: A Bibliometric Study of Electronic Commerce in China

    Science.gov (United States)

    Fatima, Anam; Abbas, Asad; Ming, Wan; Zaheer, Ahmad Nawaz; Akhtar, Masood-ul-Hassan

    2017-01-01

    Technology plays a vital role in every field of life especially in business and education. Electronic commerce (EC) begins in the year of 1991 right after internet was introduced for commercial use. It is known to be the 12th five years' plan (2011 to 2015) of Chinese Ministry of Industry and Information Technology. The main "objective"…

  12. Clinician‐selected Electronic Information Resources do not Guarantee Accuracy in Answering Primary Care Physicians’ Information Needs. A review of: McKibbon, K. Ann, and Douglas B. Fridsma. “Effectiveness of Clinician‐selected Electronic Information Resources for Answering Primary Care Physicians’ Information Needs.” Journal of the American Medical Informatics Association 13.6 (2006: 653‐9.

    Directory of Open Access Journals (Sweden)

    Martha Ingrid Preddie

    2008-03-01

    Full Text Available Objective – To determine if electronic information resources selected by primary care physicians improve their ability to answer simulated clinical questions.Design – An observational study utilizing hour‐long interviews and think‐aloud protocols.Setting – The offices and clinics of primary care physicians in Canada and the United States.Subjects – Twenty‐five primary care physicians of whom 4 were women, 17 were from Canada, 22 were family physicians,and 24 were board certified.Methods – Participants provided responses to 23 multiple‐choice questions. Each physician then chose two questions and looked for the answers utilizing information resources of their own choice. The search processes, chosen resources and search times were noted. These were analyzed along with data on the accuracy of the answers and certainties related to the answer to each clinical question prior to the search.Main results – Twenty‐three physicians sought answers to 46 simulated clinical questions. Utilizing only electronic information resources, physicians spent a mean of 13.0 (SD 5.5 minutes searching for answers to the questions, an average of 7.3(SD 4.0 minutes for the first question and 5.8 (SD 2.2 minutes to answer the second question. On average, 1.8 resources were utilized per question. Resources that summarized information, such as the Cochrane Database of Systematic Reviews, UpToDate and Clinical Evidence, were favored 39.2% of the time, MEDLINE (Ovid and PubMed 35.7%, and Internet resources including Google 22.6%. Almost 50% of the search and retrieval strategies were keyword‐based, while MeSH, subheadings and limiting were used less frequently. On average, before searching physicians answered 10 of 23 (43.5% questions accurately. For questions that were searched using clinician‐selected electronic resources, 18 (39.1% of the 46 answers were accurate before searching, while 19 (42.1% were accurate after searching. The difference of

  13. SAGES: A Suite of Freely-Available Software Tools for Electronic Disease Surveillance in Resource-Limited Settings

    Science.gov (United States)

    2011-05-10

    3] Recently, the emergence of the novel 2009 influenza A ( H1N1 ) virus and the SARS coronavirus have demonstrated how rapidly pathogens can spread...standards in both minimum data sets for disease surveillance and routine diagnosis and care. Analysis & Visualization. As previously discussed, the...g002 SAGES Electronic Disease Surveillance PLoS ONE | www.plosone.org 3 May 2011 | Volume 6 | Issue 5 | e19750 for pandemic influenza as well as

  14. Share and share alike: encouraging the reuse of academic resources through the Scottish electronic Staff Development Library

    Directory of Open Access Journals (Sweden)

    Lorna M. Campbell

    2001-12-01

    Full Text Available The Scottish electronic Staff Development Library (http://www.sesdl.scotcit.acuk is an ongoing collaborative project involving the Universities of Edinburgh, Paisley and Strathclyde which has been funded by SHEFC as part of their current ScotCIT Programme (http:llwww.scotcit.ac.uk. This project is being developed in response to the increasing demand for flexible, high-quality staff development materials.

  15. Vitamin B biosynthesis in plants.

    Science.gov (United States)

    Roje, Sanja

    2007-07-01

    The vitamin B complex comprises water-soluble enzyme cofactors and their derivatives that are essential contributors to diverse metabolic processes in plants as well as in animals and microorganisms. Seven vitamins form this complex: B1 (thiamin (1)), B2 (riboflavin (2)), B3 (niacin (3)), B5 (pantothenic acid (4)), B6 (pyridoxine, pyridoxal (5), and pyridoxamine), B8 (biotin (6)), and B9 (folate (7)). All seven B vitamins are required in the human diet for proper nutrition because humans lack enzymes to synthesize these compounds de novo. This review aims to summarize the present knowledge of vitamin B biosynthesis in plants.

  16. Success factors for implementing and sustaining a mature electronic medical record in a low-resource setting: a case study of iSanté in Haiti.

    Science.gov (United States)

    deRiel, E; Puttkammer, N; Hyppolite, N; Diallo, J; Wagner, S; Honoré, J G; Balan, J G; Celestin, N; Vallès, J S; Duval, N; Thimothé, G; Boncy, J; Coq, N R L; Barnhart, S

    2018-03-01

    Electronic health information systems, including electronic medical records (EMRs), have the potential to improve access to information and quality of care, among other things. Success factors and challenges for novel EMR implementations in low-resource settings have increasingly been studied, although less is known about maturing systems and sustainability. One systematic review identified seven categories of implementation success factors: ethical, financial, functionality, organizational, political, technical and training. This case study applies this framework to iSanté, Haiti's national EMR in use in more than 100 sites and housing records for more than 750 000 patients. The author group, consisting of representatives of different agencies within the Haitian Ministry of Health (MSPP), funding partner the Centers for Disease Control and Prevention (CDC) Haiti, and implementing partner the International Training and Education Center for Health (I-TECH), identify successes and lessons learned according to the seven identified categories, and propose an additional cross-cutting category, sustainability. Factors important for long-term implementation success of complex information systems are balancing investments in hardware and software infrastructure upkeep, user capacity and data quality control; designing and building a system within the context of the greater eHealth ecosystem with a plan for interoperability and data exchange; establishing system governance and strong leadership to support local system ownership and planning for system financing to ensure sustainability. Lessons learned from 10 years of implementation of the iSanté EMR system are relevant to sustainability of a full range of increasingly interrelated information systems (e.g. for laboratory, supply chain, pharmacy and human resources) in the health sector in low-resource settings. © The Author 2017. Published by Oxford University Press in association with The London School of Hygiene

  17. A partnership model for implementing electronic health records in resource-limited primary care settings: experiences from two nurse-managed health centers.

    Science.gov (United States)

    Dennehy, Patricia; White, Mary P; Hamilton, Andrew; Pohl, Joanne M; Tanner, Clare; Onifade, Tiffiani J; Zheng, Kai

    2011-01-01

    To present a partnership-based and community-oriented approach designed to ease provider anxiety and facilitate the implementation of electronic health records (EHR) in resource-limited primary care settings. The approach, referred to as partnership model, was developed and iteratively refined through the research team's previous work on implementing health information technology (HIT) in over 30 safety net practices. This paper uses two case studies to illustrate how the model was applied to help two nurse-managed health centers (NMHC), a particularly vulnerable primary care setting, implement EHR and get prepared to meet the meaningful use criteria. The strong focus of the model on continuous quality improvement led to eventual implementation success at both sites, despite difficulties encountered during the initial stages of the project. There has been a lack of research, particularly in resource-limited primary care settings, on strategies for abating provider anxiety and preparing them to manage complex changes associated with EHR uptake. The partnership model described in this paper may provide useful insights into the work shepherded by HIT regional extension centers dedicated to supporting resource-limited communities disproportionally affected by EHR adoption barriers. NMHC, similar to other primary care settings, are often poorly resourced, understaffed, and lack the necessary expertise to deploy EHR and integrate its use into their day-to-day practice. This study demonstrates that implementation of EHR, a prerequisite to meaningful use, can be successfully achieved in this setting, and partnership efforts extending far beyond the initial software deployment stage may be the key.

  18. Biosynthesis of bacterial aromatic polyketides.

    Science.gov (United States)

    Zhan, Jixun

    2009-01-01

    Aromatic polyketides represent important members of the family of polyketides, which have displayed a wide assortment of bioactive properties, such as antibacterial, antitumor, and antiviral activities. Bacterial aromatic polyketides are mainly synthesized by type II polyketide synthases (PKSs). Whereas malonyl-CoA is exclusively used as the extender unit, starter units can vary in different aromatic polyketide biosynthetic pathways, leading to a variety of polyketide backbones. Once the polyketide chains are elongated by the minimal PKSs to the full length, the immediate tailoring enzymes including ketoreductases, oxygenases and cyclases will work on the nascent chains to form aromatic structures, which will be further decorated by those late tailoring enzymes such as methyltransferases and glycosyltransferases. The mechanistic studies on the biosynthetic pathways of aromatic polyketides such as oxytetracycline and pradimicin A have been extensively carried out in recent years. Engineered biosynthesis of novel "unnatural" polyketides has been achieved in heterologous hosts such as Streptomyces coelicolor and Escherichia coli. This review covers the most recent advances in aromatic polyketide biosynthesis, which provide new enzymes or methods for building novel polyketide biosynthetic machinery.

  19. Fatty acid biosynthesis in actinomycetes

    Science.gov (United States)

    Gago, Gabriela; Diacovich, Lautaro; Arabolaza, Ana; Tsai, Shiou-Chuan; Gramajo, Hugo

    2011-01-01

    All organisms that produce fatty acids do so via a repeated cycle of reactions. In mammals and other animals, these reactions are catalyzed by a type I fatty acid synthase (FAS), a large multifunctional protein to which the growing chain is covalently attached. In contrast, most bacteria (and plants) contain a type II system in which each reaction is catalyzed by a discrete protein. The pathway of fatty acid biosynthesis in Escherichia coli is well established and has provided a foundation for elucidating the type II FAS pathways in other bacteria (White et al., 2005). However, fatty acid biosynthesis is more diverse in the phylum Actinobacteria: Mycobacterium, possess both FAS systems while Streptomyces species have only the multi-enzyme FAS II system and Corynebacterium species exclusively FAS I. In this review we present an overview of the genome organization, biochemical properties and physiological relevance of the two FAS systems in the three genera of actinomycetes mentioned above. We also address in detail the biochemical and structural properties of the acyl-CoA carboxylases (ACCases) that catalyzes the first committed step of fatty acid synthesis in actinomycetes, and discuss the molecular bases of their substrate specificity and the structure-based identification of new ACCase inhibitors with anti-mycobacterial properties. PMID:21204864

  20. Genome of wild olive and the evolution of oil biosynthesis.

    Science.gov (United States)

    Unver, Turgay; Wu, Zhangyan; Sterck, Lieven; Turktas, Mine; Lohaus, Rolf; Li, Zhen; Yang, Ming; He, Lijuan; Deng, Tianquan; Escalante, Francisco Javier; Llorens, Carlos; Roig, Francisco J; Parmaksiz, Iskender; Dundar, Ekrem; Xie, Fuliang; Zhang, Baohong; Ipek, Arif; Uranbey, Serkan; Erayman, Mustafa; Ilhan, Emre; Badad, Oussama; Ghazal, Hassan; Lightfoot, David A; Kasarla, Pavan; Colantonio, Vincent; Tombuloglu, Huseyin; Hernandez, Pilar; Mete, Nurengin; Cetin, Oznur; Van Montagu, Marc; Yang, Huanming; Gao, Qiang; Dorado, Gabriel; Van de Peer, Yves

    2017-10-31

    Here we present the genome sequence and annotation of the wild olive tree ( Olea europaea var. sylvestris ), called oleaster, which is considered an ancestor of cultivated olive trees. More than 50,000 protein-coding genes were predicted, a majority of which could be anchored to 23 pseudochromosomes obtained through a newly constructed genetic map. The oleaster genome contains signatures of two Oleaceae lineage-specific paleopolyploidy events, dated at ∼28 and ∼59 Mya. These events contributed to the expansion and neofunctionalization of genes and gene families that play important roles in oil biosynthesis. The functional divergence of oil biosynthesis pathway genes, such as FAD2 , SACPD, EAR , and ACPTE , following duplication, has been responsible for the differential accumulation of oleic and linoleic acids produced in olive compared with sesame, a closely related oil crop. Duplicated oleaster FAD2 genes are regulated by an siRNA derived from a transposable element-rich region, leading to suppressed levels of FAD2 gene expression. Additionally, neofunctionalization of members of the SACPD gene family has led to increased expression of SACPD2 , 3 , 5 , and 7 , consequently resulting in an increased desaturation of steric acid. Taken together, decreased FAD2 expression and increased SACPD expression likely explain the accumulation of exceptionally high levels of oleic acid in olive. The oleaster genome thus provides important insights into the evolution of oil biosynthesis and will be a valuable resource for oil crop genomics.

  1. Microbial Biosynthesis of Silver Nanoparticles in Different Culture Media.

    Science.gov (United States)

    Luo, Ke; Jung, Samuel; Park, Kyu-Hwan; Kim, Young-Rok

    2018-01-31

    Microbial biosynthesis of metal nanoparticles has been extensively studied for the applications in biomedical sciences and engineering. However, the mechanism for their synthesis through microorganism is not completely understood. In this study, several culture media were investigated for their roles in the microbial biosynthesis of silver nanoparticles (AgNPs). The size and morphology of the synthesized AgNPs were analyzed by UV-vis spectroscopy, Fourier-transform-infrared (FT-IR), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The results demonstrated that nutrient broth (NB) and Mueller-Hinton broth (MHB) among tested media effectively reduced silver ions to form AgNPs with different particle size and shape. Although the involved microorganism enhanced the reduction of silver ions, the size and shape of the particles were shown to mainly depend on the culture media. Our findings suggest that the growth media of bacterial culture play an important role in the synthesis of metallic nanoparticles with regard to their size and shape. We believe our findings would provide useful information for further exploration of microbial biosynthesis of AgNPs and their biomedical applications.

  2. Comparative transcriptome analysis of different chemotypes elucidates withanolide biosynthesis pathway from medicinal plant Withania somnifera.

    Science.gov (United States)

    Gupta, Parul; Goel, Ridhi; Agarwal, Aditya Vikram; Asif, Mehar Hasan; Sangwan, Neelam Singh; Sangwan, Rajender Singh; Trivedi, Prabodh Kumar

    2015-12-21

    Withania somnifera is one of the most valuable medicinal plants synthesizing secondary metabolites known as withanolides. Despite pharmaceutical importance, limited information is available about the biosynthesis of withanolides. Chemo-profiling of leaf and root tissues of Withania suggest differences in the content and/or nature of withanolides in different chemotypes. To identify genes involved in chemotype and/or tissue-specific withanolide biosynthesis, we established transcriptomes of leaf and root tissues of distinct chemotypes. Genes encoding enzymes for intermediate steps of terpenoid backbone biosynthesis with their alternatively spliced forms and paralogous have been identified. Analysis suggests differential expression of large number genes among leaf and root tissues of different chemotypes. Study also identified differentially expressing transcripts encoding cytochrome P450s, glycosyltransferases, methyltransferases and transcription factors which might be involved in chemodiversity in Withania. Virus induced gene silencing of the sterol ∆7-reductase (WsDWF5) involved in the synthesis of 24-methylene cholesterol, withanolide backbone, suggests role of this enzyme in biosynthesis of withanolides. Information generated, in this study, provides a rich resource for functional analysis of withanolide-specific genes to elucidate chemotype- as well as tissue-specific withanolide biosynthesis. This genomic resource will also help in development of new tools for functional genomics and breeding in Withania.

  3. Exploring the fungal protein cadre in the biosynthesis of PbSe quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, Jaya Mary; Sharma, Sumit; Balakrishnan, Raj Mohan, E-mail: rajmohanbala@gmail.com

    2017-02-15

    Highlights: • Pb and Se stress activates specific metal detoxification surge in the fungus. • Fungus releases phytochelatins, metallothioneins, super oxide dismutases etc. • These mechanisms capacitate the fungi as bio-factories for synthesis of PbSe QDs. • A pathway for PbSe QD biosynthesis by marine Aspergillus terreus was elucidated - Abstract: While a large number of microbial sources have recently emerged as potent sources for biosynthesis of chalcogenide quantum dots (QDs), studies regarding their biomimetic strategies that initiate QD biosynthesis are scarce. The present study describes several mechanistic aspects of PbSe QD biosynthesis using marine Aspergillus terreus. Scanning electron microscopic (SEM) studies indicated distinctive morphological features such as abrasion and agglomeration on the fungal biomass after the biosynthesis reaction. Further, the biomass subsequent to the heavy metal/metalloid precursor was characterized with spectral signatures typical to primary and secondary stress factors such as thiol compounds and oxalic acid using Fourier Transform Infra-Red Spectroscopic (FTIR) analysis. An increase in the total protein content in the reaction mixture after biosynthesis was another noteworthy observation. Further, metal-phytochelatins were identified as the prominent metal-ion trafficking components in the reaction mixture using Liquid Chromatography Mass Spectroscopic analysis (LCMS). Subsequent assays confirmed the involvement of metal binding peptides namely metallothioneins and other anti-oxidant enzymes that might have played a prominent role in the microbial metal detoxification system for the biosynthesis of PbSe QDs. Based on these findings a possible mechanism for the biosynthesis of PbSe QDs by marine A. terreus has been elucidated.

  4. Tyrosine biosynthesis, metabolism, and catabolism in plants.

    Science.gov (United States)

    Schenck, Craig A; Maeda, Hiroshi A

    2018-05-01

    L-Tyrosine (Tyr) is an aromatic amino acid (AAA) required for protein synthesis in all organisms, but synthesized de novo only in plants and microorganisms. In plants, Tyr also serves as a precursor of numerous specialized metabolites that have diverse physiological roles as electron carriers, antioxidants, attractants, and defense compounds. Some of these Tyr-derived plant natural products are also used in human medicine and nutrition (e.g. morphine and vitamin E). While the Tyr biosynthesis and catabolic pathways have been extensively studied in microbes and animals, respectively, those of plants have received much less attention until recently. Accumulating evidence suggest that the Tyr biosynthetic pathways differ between microbes and plants and even within the plant kingdom, likely to support the production of lineage-specific plant specialized metabolites derived from Tyr. The interspecies variations of plant Tyr pathway enzymes can now be used to enhance the production of Tyr and Tyr-derived compounds in plants and other synthetic biology platforms. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. The regulation and biosynthesis of antimycins

    Directory of Open Access Journals (Sweden)

    Ryan F. Seipke

    2013-11-01

    Full Text Available Antimycins (>40 members were discovered nearly 65 years ago but the discovery of the gene cluster encoding antimycin biosynthesis in 2011 has facilitated rapid progress in understanding the unusual biosynthetic pathway. Antimycin A is widely used as a piscicide in the catfish farming industry and also has potent killing activity against insects, nematodes and fungi. The mode of action of antimycins is to inhibit cytochrome c reductase in the electron transport chain and halt respiration. However, more recently, antimycin A has attracted attention as a potent and selective inhibitor of the mitochondrial anti-apoptotic proteins Bcl-2 and Bcl-xL. Remarkably, this inhibition is independent of the main mode of action of antimycins such that an artificial derivative named 2-methoxyantimycin A inhibits Bcl-xL but does not inhibit respiration. The Bcl-2/Bcl-xL family of proteins are over-produced in cancer cells that are resistant to apoptosis-inducing chemotherapy agents, so antimycins have great potential as anticancer drugs used in combination with existing chemotherapeutics. Here we review what is known about antimycins, the regulation of the ant gene cluster and the unusual biosynthetic pathway.

  6. Utility of the electronic information resource UpToDate for clinical decision-making at bedside rounds.

    Science.gov (United States)

    Phua, J; See, K C; Khalizah, H J; Low, S P; Lim, T K

    2012-02-01

    Clinical questions often arise at daily hospital bedside rounds. Yet, little information exists on how the search for answers may be facilitated. The aim of this prospective study was, therefore, to evaluate the overall utility, including the feasibility and usefulness of incorporating searches of UpToDate, a popular online information resource, into rounds. Doctors searched UpToDate for any unresolved clinical questions during rounds for patients in general medicine and respiratory wards, and in the medical intensive care unit of a tertiary teaching hospital. The nature of the questions and the results of the searches were recorded. Searches were deemed feasible if they were completed during the rounds and useful if they provided a satisfactory answer. A total of 157 UpToDate searches were performed during the study period. Questions were raised by all ranks of clinicians from junior doctors to consultants. The searches were feasible and performed immediately during rounds 44% of the time. Each search took a median of three minutes (first quartile: two minutes, third quartile: five minutes). UpToDate provided a useful and satisfactory answer 75% of the time, a partial answer 17% of the time and no answer 9% of the time. It led to a change in investigations, diagnosis or management 37% of the time, confirmed what was originally known or planned 38% of the time and had no effect 25% of the time. Incorporating UpToDate searches into daily bedside rounds was feasible and useful in clinical decision-making.

  7. Regulatory variability of camalexin biosynthesis.

    Science.gov (United States)

    Schuhegger, Regina; Rauhut, Thomas; Glawischnig, Erich

    2007-05-01

    The anthranilate synthase ASA1, CYP79B2 and CYP71B15 (PAD3) are biosynthetic genes of the Arabidopsis phytoalexin camalexin, which are induced after pathogen infection and abiotic treatments like silver nitrate spraying. The natural variation of camalexin biosynthesis in response to Pseudomonas syringae infection was determined in several ecotypes, and differential CYP71B15 regulation as a potential basis for this variation was investigated. The expression of camalexin biosynthetic genes was restricted to the tissue undergoing cell death. After droplet infection with Alternaria alternata, a potent camalexin inducer in the Col-0 ecotype, camalexin formation and the induction of ASA1, CYP79B2 and CYP71B15 were strictly co-localized with the infection site.

  8. Analysis of RNA biosynthesis in tobacco cell infected by pimiento ring virus

    International Nuclear Information System (INIS)

    Silva, D.M.; Nogueira, N.L.; Lage, G.

    1984-01-01

    The results about the RNA biosynthesis of pimiento ring virus are analysed. The possible virus influence on the nucleolus, mitochondria and chloroplast of the cellular RNA is studied by electron microscopy radio-authogram. The presence of the virus in the cell seems to modify 3 H-uridine transport to hostess cell interior. (M.A.C.) [pt

  9. [Biosynthesis of silver nanoparticles with the participation of extracellular Mn-dependent peroxidase from Azospirillum].

    Science.gov (United States)

    Kupryashina, M A; Vetchinkina, E P; Nikitina, V E

    2016-01-01

    The accumulation of nanoparticles of colloidal silver with spherical shape in culture liquid of Azospirillum brasilense has been shown by transmission electron microscopy. Bacterial extracellular Mn-peroxidases were found to participate in silver reduction from silver nitrate with the formation of nanoparticles. A mechanism of extracellular biosynthesis of silver nanoparticles by A. brasilense bacteria was proposed

  10. Comprehensive evaluation of electronic medical record system use and user satisfaction at five low-resource setting hospitals in ethiopia.

    Science.gov (United States)

    Tilahun, Binyam; Fritz, Fleur

    2015-05-25

    Electronic medical record (EMR) systems are increasingly being implemented in hospitals of developing countries to improve patient care and clinical service. However, only limited evaluation studies are available concerning the level of adoption and determinant factors of success in those settings. The objective of this study was to assess the usage pattern, user satisfaction level, and determinants of health professional's satisfaction towards a comprehensive EMR system implemented in Ethiopia where parallel documentation using the EMR and the paper-based medical records is in practice. A quantitative, cross-sectional study design was used to assess the usage pattern, user satisfaction level, and determinant factors of an EMR system implemented in Ethiopia based on the DeLone and McLean model of information system success. Descriptive statistical methods were applied to analyze the data and a binary logistic regression model was used to identify determinant factors. Health professionals (N=422) from five hospitals were approached and 406 responded to the survey (96.2% response rate). Out of the respondents, 76.1% (309/406) started to use the system immediately after implementation and user training, but only 31.7% (98/309) of the professionals reported using the EMR during the study (after 3 years of implementation). Of the 12 core EMR functions, 3 were never used by most respondents, and they were also unaware of 4 of the core EMR functions. It was found that 61.4% (190/309) of the health professionals reported over all dissatisfaction with the EMR (median=4, interquartile range (IQR)=1) on a 5-level Likert scale. Physicians were more dissatisfied (median=5, IQR=1) when compared to nurses (median=4, IQR=1) and the health management information system (HMIS) staff (median=2, IQR=1). Of all the participants, 64.4% (199/309) believed that the EMR had no positive impact on the quality of care. The participants indicated an agreement with the system and information

  11. 圖書館事業專欄/Marketing of Electronic Information Resources: A Case of The J.D. Rockefeller Research Library, Egerton University/Nerisa Kamar

    Directory of Open Access Journals (Sweden)

    Nerisa Kamar

    2008-04-01

    Full Text Available

    This paper gives a brief overview of electronic information resources and services offered by The J.D. Rockefeller Research Library at Egerton University and the marketing of these resources. The paper examines the various reasons for marketing electronic information resources, with emphasis on the various, and illustrates marketing strategies used by J.D Rockefeller Research library towards effective utilization of the available resources in supporting research, teaching and learning. These strategies include use of posters, notices, brochures, telephone calls, Current Awareness Services (CAS, workshops and seminars, and decentralization of services, among others. It concludes with a discussion of cost effective use of these strategies in research and teaching.

    頁次:89-93

  12. Randomized Controlled Trial of Electronic Care Plan Alerts and Resource Utilization by High Frequency Emergency Department Users with Opioid Use Disorder

    Directory of Open Access Journals (Sweden)

    Niels Rathlev, MD

    2016-01-01

    Full Text Available Introduction: There is a paucity of literature supporting the use of electronic alerts for patients with high frequency emergency department (ED use. We sought to measure changes in opioid prescribing and administration practices, total charges and other resource utilization using electronic alerts to notify providers of an opioid-use care plan for high frequency ED patients. Methods: This was a randomized, non-blinded, two-group parallel design study of patients who had 1 opioid use disorder and 2 high frequency ED use. Three affiliated hospitals with identical electronic health records participated. Patients were randomized into “Care Plan” versus “Usual Care groups”. Between the years before and after randomization, we compared as primary outcomes the following: 1 opioids (morphine mg equivalents prescribed to patients upon discharge and administered to ED and inpatients; 2 total medical charges, and the numbers of; 3 ED visits, 4 ED visits with advanced radiologic imaging (computed tomography [CT] or magnetic resonance imaging [MRI] studies, and 5 inpatient admissions. Results: A total of 40 patients were enrolled. For ED and inpatients in the “Usual Care” group, the proportion of morphine mg equivalents received in the post-period compared with the pre-period was 15.7%, while in the “Care Plan” group the proportion received in the post-period compared with the pre-period was 4.5% (ratio=0.29, 95% CI [0.07-1.12]; p=0.07. For discharged patients in the “Usual Care” group, the proportion of morphine mg equivalents prescribed in the post-period compared with the pre-period was 25.7% while in the “Care Plan” group, the proportion prescribed in the post-period compared to the pre-period was 2.9%. The “Care Plan” group showed an 89% greater proportional change over the periods compared with the “Usual Care” group (ratio=0.11, 95% CI [0.01-0.092]; p=0.04. Care plans did not change the total charges, or, the numbers

  13. Monoterpene biosynthesis potential of plant subcellular compartments

    NARCIS (Netherlands)

    Dong, L.; Jongedijk, E.J.; Bouwmeester, H.J.; Krol, van der A.R.

    2016-01-01

    Subcellular monoterpene biosynthesis capacity based on local geranyl diphosphate (GDP) availability or locally boosted GDP production was determined for plastids, cytosol and mitochondria. A geraniol synthase (GES) was targeted to plastids, cytosol, or mitochondria. Transient expression in Nicotiana

  14. Antibacterial Targets in Fatty Acid Biosynthesis

    Science.gov (United States)

    Wright, H. Tonie; Reynolds, Kevin A.

    2008-01-01

    Summary The fatty acid biosynthesis pathway is an attractive but still largely unexploited target for development of new anti-bacterial agents. The extended use of the anti-tuberculosis drug isoniazid and the antiseptic triclosan, which are inhibitors of fatty acid biosynthesis, validates this pathway as a target for anti-bacterial development. Differences in subcellular organization of the bacterial and eukaryotic multi-enzyme fatty acid synthase systems offer the prospect of inhibitors with host vs. target specificity. Platensimycin, platencin, and phomallenic acids, newly discovered natural product inhibitors of the condensation steps in fatty acid biosynthesis, represent new classes of compounds with antibiotic potential. An almost complete catalogue of crystal structures for the enzymes of the type II fatty acid biosynthesis pathway can now be exploited in the rational design of new inhibitors, as well as the recently published crystal structures of type I FAS complexes. PMID:17707686

  15. Lincomycin, cultivation of producing strains and biosynthesis

    Czech Academy of Sciences Publication Activity Database

    Spížek, Jaroslav; Řezanka, Tomáš

    2004-01-01

    Roč. 63, - (2004), s. 510-519 ISSN 0175-7598 Institutional research plan: CEZ:AV0Z5020903 Keywords : lincomycin * cultivation * biosynthesis Subject RIV: EE - Microbiology, Virology Impact factor: 2.358, year: 2004

  16. Control of tylosin biosynthesis in Streptomyces fradiae.

    Science.gov (United States)

    Cundliffe, Eric

    2008-09-01

    Tylosin biosynthesis is controlled in cascade fashion by multiple transcriptional regulators, acting positively or negatively, in conjunction with a signalling ligand that acts as a classical inducer. The roles of regulatory gene products have been characterized by a combination of gene expression analysis and fermentation studies, using engineered strains of S. fradiae in which specific genes were inactivated or overexpressed. Among various novel features of the regulatory model, involvement of the signalling ligand is not essential for tylosin biosynthesis.

  17. Biosynthesis of antibiotic chuangxinmycin from Actinoplanes tsinanensis

    Directory of Open Access Journals (Sweden)

    Yuanyuan Shi

    2018-03-01

    Full Text Available Chuangxinmycin is an antibiotic isolated from Actinoplanes tsinanensis CPCC 200056 in the 1970s with a novel indole-dihydrothiopyran heterocyclic skeleton. Chuangxinmycin showed in vitro antibacterial activity and in vivo efficacy in mouse infection models as well as preliminary clinical trials. But the biosynthetic pathway of chuangxinmycin has been obscure since its discovery. Herein, we report the identification of a stretch of DNA from the genome of A. tsinanensis CPCC 200056 that encodes genes for biosynthesis of chuangxinmycin by bioinformatics analysis. The designated cxn cluster was then confirmed to be responsible for chuangxinmycin biosynthesis by direct cloning and heterologous expressing in Streptomyces coelicolor M1146. The cytochrome P450 CxnD was verified to be involved in the dihydrothiopyran ring closure reaction by the identification of seco-chuangxinmycin in S. coelicolor M1146 harboring the cxn gene cluster with an inactivated cxnD. Based on these results, a plausible biosynthetic pathway for chuangxinmycin biosynthesis was proposed, by hijacking the primary sulfur transfer system for sulfur incorporation. The identification of the biosynthetic gene cluster of chuangxinmycin paves the way for elucidating the detail biochemical machinery for chuangxinmycin biosynthesis, and provides the basis for the generation of novel chuangxinmycin derivatives by means of combinatorial biosynthesis and synthetic biology. KEY WORDS: Chuangxinmycin, Actinoplanes tsinanensis, Biosynthesis gene cluster, Heterologous expression, Cytochrome P450, Seco-chuangxinmycin, C–S bond formation, Sulfur incorporation

  18. There is a Relationship between Resource Expenditures and Reference Transactions in Academic Libraries. A Review of: Dubnjakovic, A. (2012. Electronic resource expenditure and the decline in reference transaction statistics in academic libraries. Journal of Academic Librarianship, 38(2, 94-100. doi:10.1016/j.acalib.2012.01.001

    Directory of Open Access Journals (Sweden)

    Annie M. Hughes

    2013-03-01

    Full Text Available Objective – To provide an analysis of the impact of expenditures on electronic resourcesand gate counts on the increase or decrease in reference transactions.Design – Analysis of results of existing survey data from the National Center for Educational Statistics (NCES 2006 Academic Library Survey(ALS.Setting – Academic libraries in the United States.Subjects – 3925 academic library respondents.Methods – The author chose to use survey data collected from the 2006 ALS conducted bythe NCES. The survey included data on various topics related to academic libraries, but in the case of this study, the author chose to analyze three of the 193 variables included. The three variables: electronic books expenditure, computer hardware and software, and expenditures on bibliographic utilities, were combined into one variable called electronic resource expenditure. Gate counts were also considered as a variable. Electronic resource expenditure was also split as a variable into three groups: low, medium, and high. Multiple regression analysis and general linear modeling, along with tests of reliability, were employed. Main Results – The author determined that low, medium, and high spenders with regard to electronic resources exhibited differences in gate counts, and gate counts have an effect on reference transactions in any given week. Gate counts tend to not have much of an effect on reference transactions for the higher spenders, and higher spenders tend to have a higher number of reference transactions overall. Low spenders have lower gate counts and also a lower amount of reference transactions.Conclusion – The findings from this study show that academic libraries spending more on electronic resources also tend to have an increase with regard to reference transactions. The author also concludes that library spaces are no longer the determining factor with regard to number of reference transactions. Spending more on electronic resources is

  19. Biosynthesis of silver nanoparticles using Ocimum sanctum (Tulsi) leaf extract and screening its antimicrobial activity

    Science.gov (United States)

    Singhal, Garima; Bhavesh, Riju; Kasariya, Kunal; Sharma, Ashish Ranjan; Singh, Rajendra Pal

    2011-07-01

    Development of green nanotechnology is generating interest of researchers toward ecofriendly biosynthesis of nanoparticles. In this study, biosynthesis of stable silver nanoparticles was done using Tulsi ( Ocimum sanctum) leaf extract. These biosynthesized nanoparticles were characterized with the help of UV-vis spectrophotometer, Atomic Absorption Spectroscopy (AAS), Dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Transmission electron microscopy (TEM). Stability of bioreduced silver nanoparticles was analyzed using UV-vis absorption spectra, and their antimicrobial activity was screened against both gram-negative and gram-positive microorganisms. It was observed that O. sanctum leaf extract can reduce silver ions into silver nanoparticles within 8 min of reaction time. Thus, this method can be used for rapid and ecofriendly biosynthesis of stable silver nanoparticles of size range 4-30 nm possessing antimicrobial activity suggesting their possible application in medical industry.

  20. Political Unrest and Educational Electronic Resource Usage in a Conflict Zone, Kashmir (Indian Administered Kashmir): Log Analysis as Politico Analytical Tool=Hindistan Tarafından Yönetilen Keşmir Anlaşmazlık Bölgesi’nde Siyasi Karışıklık ve Eğitimle İlgili Elektronik Kaynakların Kullanımı: Siyasi Analiz Aracı Olarak Log Analizleri

    OpenAIRE

    Sumeer Gul; Samrin Nabi; Samina Mushtaq; Tariq Ahmad Shah; Suhail Ahmad

    2013-01-01

    Electronic resource usage has proved as one of the best decision making tools in the library setups. Electronic resource usage in relation to the political disturbance can act as one of the tools to highlight the impact of political disturbance on educational setups in general and the electronic resource usage in particular. The study takes a serious look in the electronic resource usage in Kashmir and the impact of unrest on it. The paper highlights a relational platform between educat...

  1. The Spatial Organization of Glucosinolate Biosynthesis

    DEFF Research Database (Denmark)

    Nintemann, Sebastian

    between the individual classes of glucosinolates under constitutive and induced conditions and identified the source tissues of these defense compounds. Protein-protein interaction studies were carried out to investigate the subcellular organization of glucosinolate biosynthesis. We identified a family...... resistance and nutritional value and many plant specialized metabolites are of high value due to their health promoting characteristics. Glucosinolates are defense compounds found in many crops from the Brassicaceae family and are of high interest because of their nutritional and antinutritional properties...... cells is an open question. Likewise, it is not known how glucosinolate biosynthesis is orchestrated at the subcellular level. These open questions were addressed with several approaches in this project, with the aim of shedding light on the spatial organization of glucosinolate biosynthesis from...

  2. Biosynthesis and structural characterization of silver nanoparticles from bacterial isolates

    Energy Technology Data Exchange (ETDEWEB)

    Zaki, Sahar, E-mail: saharzaki@yahoo.com [Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, Mubarak City for Scientific Research and Technology Applications, Alexandria, 21934 New Burgelarab City (Egypt); El Kady, M.F. [Fabrication Technology Department, Advanced Technology and New Materials Research Institute (ATNMRI), Mubarak City for Scientific Research and Technology Applications, Alexandria (Egypt); Abd-El-Haleem, Desouky [Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, Mubarak City for Scientific Research and Technology Applications, Alexandria, 21934 New Burgelarab City (Egypt)

    2011-10-15

    Graphical abstract: In this study five bacterial isolates belong to different genera were found to be able to biosynthesize silver nanoparticles. Biosynthesis and spectral characterization are reported here. Highlights: {yields} About 300 bacterial isolates were screened for their ability to produce nanosilvers {yields} Five of them were potential candidates for synthesis of silver nanoparticles {yields} Production of silver nanoparticles was examined using UV-Vis, XRD, SEM and EDS. {yields} The presence of nanoparticles with all five bacterial isolates was confirmed. -- Abstract: This study aimed to develop a green process for biosynthesis of silver nanomaterials by some Egyptian bacterial isolates. This target was achieved by screening an in-house culture collection consists of 300 bacterial isolates for silver nanoparticle formation. Through screening process, it was observed that strains belonging to Escherichia coli (S30, S78), Bacillus megaterium (S52), Acinetobacter sp. (S7) and Stenotrophomonas maltophilia (S54) were potential candidates for synthesis of silver nanoparticles. The extracellular production of silver nanoparticles by positive isolates was investigated by UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results demonstrated that UV-visible spectrum of the aqueous medium containing silver ion showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy micrograph showed formation of silver nanoparticles in the range of 15-50 nm. XRD-spectrum of the silver nanoparticles exhibited 2{theta} values corresponding to the silver nanocrystal that produce in hexagonal and cubic crystal configurations with different plane of orientation. In addition, the signals of the silver atoms were observed by EDS-spectrum analysis that confirms the presence of silver nanoparticles (Ag

  3. Functional and Evolutionary Relationship between Arginine Biosynthesis and Prokaryotic Lysine Biosynthesis through α-Aminoadipate

    Science.gov (United States)

    Miyazaki, Junichi; Kobashi, Nobuyuki; Nishiyama, Makoto; Yamane, Hisakazu

    2001-01-01

    Our previous studies revealed that lysine is synthesized through α-aminoadipate in an extremely thermophilic bacterium, Thermus thermophilus HB27. Sequence analysis of a gene cluster involved in the lysine biosynthesis of this microorganism suggested that the conversion from α-aminoadipate to lysine proceeds in a way similar to that of arginine biosynthesis. In the present study, we cloned an argD homolog of T. thermophilus HB27 which was not included in the previously cloned lysine biosynthetic gene cluster and determined the nucleotide sequence. A knockout of the argD-like gene, now termed lysJ, in T. thermophilus HB27 showed that this gene is essential for lysine biosynthesis in this bacterium. The lysJ gene was cloned into a plasmid and overexpressed in Escherichia coli, and the LysJ protein was purified to homogeneity. When the catalytic activity of LysJ was analyzed in a reverse reaction in the putative pathway, LysJ was found to transfer the ɛ-amino group of N2-acetyllysine, a putative intermediate in lysine biosynthesis, to 2-oxoglutarate. When N2-acetylornithine, a substrate for arginine biosynthesis, was used as the substrate for the reaction, LysJ transferred the δ-amino group of N2-acetylornithine to 2-oxoglutarate 16 times more efficiently than when N2-acetyllysine was the amino donor. All these results suggest that lysine biosynthesis in T. thermophilus HB27 is functionally and evolutionarily related to arginine biosynthesis. PMID:11489859

  4. Interactive Electronic Decision Trees for the Integrated Primary Care Management of Febrile Children in Low Resource Settings - Review of existing tools.

    Science.gov (United States)

    Keitel, Kristina; D'Acremont, Valérie

    2018-04-20

    The lack of effective, integrated diagnostic tools pose a major challenge to the primary care management of febrile childhood illnesses. These limitations are especially evident in low-resource settings and are often inappropriately compensated by antimicrobial over-prescription. Interactive electronic decision trees (IEDTs) have the potential to close these gaps: guiding antibiotic use and better identifying serious disease. This narrative review summarizes existing IEDTs, to provide an overview of their degree of validation, as well as to identify gaps in current knowledge and prospects for future innovation. Structured literature review in PubMed and Embase complemented by google search and contact with developers. Six integrated IEDTs were identified: three (eIMCI, REC, and Bangladesh digital IMCI) based on Integrated Management of Childhood Illnesses (IMCI); four (SL eCCM, MEDSINC, e-iCCM, and D-Tree eCCM) on Integrated Community Case Management (iCCM); two (ALMANACH, MSFeCARE) with a modified IMCI content; and one (ePOCT) that integrates novel content with biomarker testing. The types of publications and evaluation studies varied greatly: the content and evidence-base was published for two (ALMANACH and ePOCT), ALMANACH and ePOCT were validated in efficacy studies. Other types of evaluations, such as compliance, acceptability were available for D-Tree eCCM, eIMCI, ALMANACH. Several evaluations are still ongoing. Future prospects include conducting effectiveness and impact studies using data gathered through larger studies to adapt the medical content to local epidemiology, improving the software and sensors, and Assessing factors that influence compliance and scale-up. IEDTs are valuable tools that have the potential to improve management of febrile children in primary care and increase the rational use of diagnostics and antimicrobials. Next steps in the evidence pathway should be larger effectiveness and impact studies (including cost analysis) and

  5. Triterpenoid biosynthesis in Euphorbia lathyris latex

    International Nuclear Information System (INIS)

    Hawkins, D.R.

    1987-11-01

    The structures of triterpenols, not previously been known, from Euphorbia lathyris latex are reported. A method for quantifying very small amounts of these compounds was developed. Concerning the biochemistry of the latex, no exogenous cofactors were required for the biosynthesis and the addition of compounds such as NADPAH and ATP do not stimulate the biosynthesis. The addition of DTE or a similar anti-oxidant was found to help reduce the oxidation of the latex, thus increasing the length of time that the latex remains active. The requirement of a divalent cation and the preference for Mn in the pellet was observed. The effect of several inhibitors on the biosynthesis of the triterpenoids was examined. Mevinolin was found to inhibit the biosynthesis of the triterpenoids from acetate, but not mevalonate. A dixon plot of the inhibition of acetate incorporation showed an I 50 concentration of 3.2 μM. Fenpropimorph was found to have little or no effect on the biosynthesis. Tridemorph was found to inhibit the biosynthesis of all of the triterpenoids with an I 50 of 4 μM. It was also observed that the cyclopropyl containing triterpenols, cycloartenol and 24-methylenecycloartenol were inhibited much more strongly than those containing an 8-9 double bond, lanosterol and 24-methylenelanosterol. The evidence indicates, but does not definetely prove, that lanosterol and 24-methylenelanosterol are not made from cycloartenol and 24-methylenecycloartenol via a ring-opening enzyme such as cycloeucalenol-obtusifoliol isomerase. The possibilty that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4- 3 H-mevalonic acid and incubating latex with a mixture of this and 14 C-mevalonic acid. From the 3 H/ 14 C ratio it was shown that cycloartenol and 24-methylenecycloartenol are not made via an intermediate containing as 8-9 double bond. 88 refs., 15 figs., 30 tabs

  6. Nucleoside antibiotics: biosynthesis, regulation, and biotechnology.

    Science.gov (United States)

    Niu, Guoqing; Tan, Huarong

    2015-02-01

    The alarming rise in antibiotic-resistant pathogens has coincided with a decline in the supply of new antibiotics. It is therefore of great importance to find and create new antibiotics. Nucleoside antibiotics are a large family of natural products with diverse biological functions. Their biosynthesis is a complex process through multistep enzymatic reactions and is subject to hierarchical regulation. Genetic and biochemical studies of the biosynthetic machinery have provided the basis for pathway engineering and combinatorial biosynthesis to create new or hybrid nucleoside antibiotics. Dissection of regulatory mechanisms is leading to strategies to increase the titer of bioactive nucleoside antibiotics. Copyright © 2014. Published by Elsevier Ltd.

  7. Combinatorial Biosynthesis of Polyketides – A Perspective

    Science.gov (United States)

    Wong, Fong T.; Khosla, Chaitan

    2012-01-01

    Since their discovery, polyketide synthases have been attractive targets of biosynthetic engineering to make “unnatural” natural products. Although combinatorial biosynthesis has made encouraging advances over the past two decades, the field remains in its infancy. In this enzyme-centric perspective, we discuss the scientific and technological challenges that could accelerate the adoption of combinatorial biosynthesis as a method of choice for the preparation of encoded libraries of bioactive small molecules. Borrowing a page from the protein structure prediction community, we propose a periodic challenge program to vet the most promising methods in the field, and to foster the collective development of useful tools and algorithms. PMID:22342766

  8. Method for determining heterologous biosynthesis pathways

    KAUST Repository

    Gao, Xin

    2017-08-10

    The present invention relates to a method and system for dynamically analyzing, determining, predicting and displaying ranked suitable heterologous biosynthesis pathways for a specified host. The present invention addresses the problem of finding suitable pathways for the endogenous metabolism of a host organism because the efficacy of heterologous biosynthesis is affected by competing endogenous pathways. The present invention is called MRE (Metabolic Route Explorer), and it was conceived and developed to systematically and dynamically search for, determine, analyze, and display promising heterologous pathways while considering competing endogenous reactions in a given host organism.

  9. Convergent Evolution of Ergothioneine Biosynthesis in Cyanobacteria.

    Science.gov (United States)

    Liao, Cangsong; Seebeck, Florian P

    2017-11-02

    Biosynthesis of N-α-trimethyl-2-thiohistidine (ergothioneine) is a frequent trait in cyanobacteria. This sulfur compound may provide essential relief from oxidative stress related to oxygenic photosynthesis. The central steps in ergothioneine biosynthesis are catalyzed by a histidine methyltransferase and an iron-dependent sulfoxide synthase. In this report, we present evidence that some cyanobacteria recruited and adapted a sulfoxide synthase from a different biosynthetic pathway to make ergothioneine. The discovery of a second origin of ergothioneine production underscores the physiological importance of this metabolite and highlights the evolutionary malleability of the thiohistidine biosynthetic machinery. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. RNA-Seq analysis for indigo biosynthesis pathway genes in Indigofera tinctoria and Polygonum tinctorium

    Directory of Open Access Journals (Sweden)

    Bijaya K. Sarangi

    2015-12-01

    Full Text Available Natural indigo is the most important blue dye for textile dyeing and valuable secondary metabolite biosynthesized in Indigofera tinctoria and Polygonum tinctorium plants. Present investigation is made to generation of gene resource for pathway enrichment and to understand possible gene expression involved in indigo biosynthesis. The data about raw reads and the transcriptome assembly project has been deposited at GenBank under the accessions SRA180766 and SRX692542 for I. tinctoria and P. tinctorium, respectively.

  11. Biosynthesis and metabolic pathways of pivalic acid

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Kolouchová, I.; Čejková, A.; Sigler, Karel

    2012-01-01

    Roč. 95, č. 6 (2012), s. 1371-1376 ISSN 0175-7598 R&D Projects: GA ČR(CZ) GAP503/11/0215 Institutional support: RVO:61388971 Keywords : Pivalic acid * Isooctane * Biosynthesis Subject RIV: EE - Microbiology, Virology Impact factor: 3.689, year: 2012

  12. Combinatorial biosynthesis of medicinal plant secondary metabolites

    NARCIS (Netherlands)

    Julsing, Mattijs K.; Koulman, Albert; Woerdenbag, Herman J.; Quax, Wim J.; Kayser, Oliver

    2006-01-01

    Combinatorial biosynthesis is a new tool in the generation of novel natural products and for the production of rare and expensive natural products. The basic concept is combining metabolic pathways in different organisms on a genetic level. As a consequence heterologous organisms provide precursors

  13. Biosynthesis of silver nanoparticles synthesized by Aspergillus

    Indian Academy of Sciences (India)

    In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities were investigated. Silver nanoparticles were extracellularly synthesized using Aspergillus flavus and the formation of nanoparticles was observed after 72 h of incubation. The results recorded from colour ...

  14. Bile acid biosynthesis and its regulation

    Directory of Open Access Journals (Sweden)

    Areta Hebanowska

    2010-10-01

    Full Text Available Bile acid biosynthesis is the main pathway of cholesterol catabolism. Bile acids are more soluble than cholesterol so are easier to excrete. As amphipathic molecules they participate in lipid digestion and absorption in the intestine and they help to excrete free cholesterol with bile. They are also ligands for nuclear receptors regulating the expression of genes involved in cholesterol metabolism. Interconversion of cholesterol into bile acids is an important point of its homeostasis. Seventeen enzymes are engaged in this process and many of them are cytochromes P450. Bile acid synthesis initiation may proceed with the “classical” pathway (starting with cholesterol hydroxylation at the C7α position or the “alternative” pathway (starting with cholesterol hydroxylation at the C27 position. Two additional pathways are possible, though their quantitative significance is small (initiated with cholesterol hydroxylations of C24 and C25 positions. Oxysterols produced are not only intermediates of bile acid biosynthesis but also important regulators of metabolism. Bile acid biosynthesis takes place in the liver, but some enzymes are also present in other organs, where they participate in regulation of cholesterol metabolism. Those enzymes are potential targets for new drugs against cholesterol metabolism disturbances. This article is a brief description of the bile acid biosynthesis pathway and participating enzymes.

  15. Biosynthesis of polyhydroxyalkanotes in wildtype yeasts | Desuoky ...

    African Journals Online (AJOL)

    Biosynthesis of the biodegradable polymers polyhydroxyalkanotes (PHAs) are studied extensively in wild type and genetically modified prokaryotic cells, however the content and structure of PHA in wild type yeasts are not well documented. The purpose of this study was to screen forty yeast isolates collected from different ...

  16. Unedoside derivatives in Nuxia and their biosynthesis

    DEFF Research Database (Denmark)

    Jensen, Søren Rosendal; Ravnkilde, Lene; Schripsema, Jan

    1998-01-01

    isolated, while from N. oppositifolia 2 "-acetyl-3 "-benzoyl-nuxioside was obtained. Both plants contained verbascoside. The biosynthesis of unedoside in N. floribunda was investigated and deoxyloganic acid was found to be a precursor, similar to wh;lt was found for the eight-carbon iridoids in Thunbergia...

  17. Biosynthesis of furanochromones in Pimpinella monoica

    Indian Academy of Sciences (India)

    polyketide origin of their aromatic and pyrone rings while the furan ring originates via an acetate-mevalonate pathway. The plant also utilises glycine and leucine as substrate via acetate. Biotransformation of 3-H-visnagin to (6) but not to (2) was also observed. Keywords. Biosynthesis; furochromones; polyketide origin; ...

  18. Biosynthesis of silver nanoparticles synthesized by Aspergillus ...

    Indian Academy of Sciences (India)

    In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities were investigated. Silver nanoparticles were extracellularly synthesized using Aspergillus flavus and the formation of nanoparticles was observed after 72 h of incubation. The results recorded from colour ...

  19. Biosynthesis of nanosilver particles using extract of Salmonella typhirium

    Directory of Open Access Journals (Sweden)

    Hamid Reza Ghorbani

    2017-05-01

    Full Text Available Development of reliable and eco-friendly processes for the synthesis of metallic nanoparticles is an important step in the field of application of nanotechnology. One of the options to achieve this objective is to use natural factories such as biological systems. In the present investigation, we report the biosynthesis of silver nanoparticles employing extract of Salmonella typhirium. Silver nanoparticles were synthesized through the reduction of aqueous Ag+ ion using the cell extract of bacterium Salmonella typhirium in the bright conditions. The synthetic process was fast and silver nanoparticles were formed within 30 min of silver ion coming in contact with the cell extract filtrate. UV–visible spectrum of the aqueous medium containing silver ion showed a peak at 415 nm corresponding to the plasmon absorbance of silver nanoparticles. The size of the nanoparticles was measured by dynamic light scattering (DLS and the morphology of nanoparticles was observed using transmission electron microscopy (TEM.

  20. Library resources on the Internet

    Science.gov (United States)

    Buchanan, Nancy L.

    1995-07-01

    Library resources are prevalent on the Internet. Library catalogs, electronic books, electronic periodicals, periodical indexes, reference sources, and U.S. Government documents are available by telnet, Gopher, World Wide Web, and FTP. Comparatively few copyrighted library resources are available freely on the Internet. Internet implementations of library resources can add useful features, such as full-text searching. There are discussion lists, Gophers, and World Wide Web pages to help users keep up with new resources and changes to existing ones. The future will bring more library resources, more types of library resources, and more integrated implementations of such resources to the Internet.

  1. Comparative Transcriptome Analysis Identifies Putative Genes Involved in the Biosynthesis of Xanthanolides in Xanthium strumarium L.

    Directory of Open Access Journals (Sweden)

    Yuanjun Li

    2016-08-01

    Full Text Available Xanthium strumarium L. is a traditional Chinese herb belonging to the Asteraceae family. The major bioactive components of this plant are sesquiterpene lactones, which include the xanthanolides. To date, the biogenesis of xanthanolides, especiallytheir downstream pathway, remains largely unknown. In X. strumarium, xanthanolides primarily accumulate in its glandular trichomes. To identify putative gene candidates involved in the biosynthesis of xanthanolides, three X. strumarium transcriptomes, which were derived from the young leaves of two different cultivars and the purified glandular trichomes from one of the cultivars, were constructed in this study. In total, 157 million clean reads were generated and assembled into 91,861 unigenes, of which 59,858 unigenes were successfully annotated. All the genes coding for known enzymes in the upstream pathway to the biosynthesis of xanthanolides were present in the X. strumarium transcriptomes. From a comparative analysis of the X. strumarium transcriptomes, this study identified a number of gene candidates that are putatively involved in the downstream pathway to the synthesis of xanthanolides, such as four unigenes encoding CYP71 P450s, 50 unigenes for dehydrogenases, and 27 genes for acetyltransferases. The possible functions of these four CYP71 candidates are extensively discussed. In addition, 116 transcription factors that were highly expressed in X. strumarium glandular trichomes were also identified. Their possible regulatory roles in the biosynthesis of sesquiterpene lactones are discussed. The global transcriptomic data for X. strumarium should provide a valuable resource for further research into the biosynthesis of xanthanolides.

  2. Herpes - resources

    Science.gov (United States)

    Genital herpes - resources; Resources - genital herpes ... following organizations are good resources for information on genital herpes : March of Dimes -- www.marchofdimes.com/pregnancy/complications- ...

  3. Analysis on Current Situation and Countermeasure of Domestic Electronic Commerce Logistics in the Internet Age——Based on Resource Dependence Theory

    Directory of Open Access Journals (Sweden)

    Zhang Jiapeng

    2017-01-01

    Full Text Available This paper analyzes the status of electric business logistics in the current Internet era in China, and combines the SWOT analysis with AHP to do the empirical analysis, then puts forward the countermeasure that the electric business logistics resource should be shared based on the resource dependence theory. Through the empirical analysis, it is found that the disadvantages and opportunities of the logistics status are important in the Internet era.The resource sharing strategy based on the resource dependence theory is more scientific. The rational use of Internet technology in electric business logistics industry can achieve “sharing”. It is of great significance for its balanced development, intelligent development and optimization and development.

  4. Combinatorial Biosynthesis – Potential and Problems

    Science.gov (United States)

    Floss, Heinz G.

    2007-01-01

    Because of their ecological functions, natural products have been optimized in evolution for interaction with biological systems and receptors. However, they have not necessarily been optimized for other desirable drug properties and thus can often be improved by structural modification. Using examples from the literature, this paper reviews the opportunities for increasing structural diversity among natural products by combinatorial biosynthesis, i.e., the genetic manipulation of biosynthetic pathways. It distinguishes between combinatorial biosynthesis in a narrower sense to generate libraries of modified structures, and metabolic engineering for the targeted formation of specific structural analogs. Some of the problems and limitations encountered with these approaches are also discussed. Work from the author’s laboratory on ansamycin antibiotics is presented which illustrates some of the opportunities and limitations. PMID:16414140

  5. Combinatorial biosynthesis of polyketides--a perspective.

    Science.gov (United States)

    Wong, Fong T; Khosla, Chaitan

    2012-04-01

    Since their discovery, polyketide synthases have been attractive targets of biosynthetic engineering to make 'unnatural' natural products. Although combinatorial biosynthesis has made encouraging advances over the past two decades, the field remains in its infancy. In this enzyme-centric perspective, we discuss the scientific and technological challenges that could accelerate the adoption of combinatorial biosynthesis as a method of choice for the preparation of encoded libraries of bioactive small molecules. Borrowing a page from the protein structure prediction community, we propose a periodic challenge program to vet the most promising methods in the field, and to foster the collective development of useful tools and algorithms. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Structural basis for phosphatidylinositol-phosphate biosynthesis

    Science.gov (United States)

    Clarke, Oliver B.; Tomasek, David; Jorge, Carla D.; Dufrisne, Meagan Belcher; Kim, Minah; Banerjee, Surajit; Rajashankar, Kanagalaghatta R.; Shapiro, Lawrence; Hendrickson, Wayne A.; Santos, Helena; Mancia, Filippo

    2015-10-01

    Phosphatidylinositol is critical for intracellular signalling and anchoring of carbohydrates and proteins to outer cellular membranes. The defining step in phosphatidylinositol biosynthesis is catalysed by CDP-alcohol phosphotransferases, transmembrane enzymes that use CDP-diacylglycerol as donor substrate for this reaction, and either inositol in eukaryotes or inositol phosphate in prokaryotes as the acceptor alcohol. Here we report the structures of a related enzyme, the phosphatidylinositol-phosphate synthase from Renibacterium salmoninarum, with and without bound CDP-diacylglycerol to 3.6 and 2.5 Å resolution, respectively. These structures reveal the location of the acceptor site, and the molecular determinants of substrate specificity and catalysis. Functional characterization of the 40%-identical ortholog from Mycobacterium tuberculosis, a potential target for the development of novel anti-tuberculosis drugs, supports the proposed mechanism of substrate binding and catalysis. This work therefore provides a structural and functional framework to understand the mechanism of phosphatidylinositol-phosphate biosynthesis.

  7. Occurrence and biosynthesis of carotenoids in phytoplankton.

    Science.gov (United States)

    Huang, Jim Junhui; Lin, Shaoling; Xu, Wenwen; Cheung, Peter Chi Keung

    2017-09-01

    Naturally occurring carotenoids are important sources of antioxidants, anti-cancer compounds and anti-inflammatory agents and there is thus considerable market demand for their pharmaceutical applications. Carotenoids are widely distributed in marine and freshwater organisms including microalgae, phytoplankton, crustaceans and fish, as well as in terrestrial plants and birds. Recently, phytoplankton-derived carotenoids have received much attention due to their abundance, rapid rate of biosynthesis and unique composition. The carotenoids that accumulate in particular phytoplankton phyla are synthesized by specific enzymes and play unique physiological roles. This review focuses on studies related to the occurrence of carotenoids in different phytoplankton phyla and the molecular aspects of their biosynthesis. Recent biotechnological advances in the isolation and characterization of some representative carotenoid synthases in phytoplankton are also discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Chemical genetics to examine cellulose biosynthesis

    Directory of Open Access Journals (Sweden)

    Seth eDebolt

    2013-01-01

    Full Text Available Long-term efforts to decode plant cellulose biosynthesis via molecular genetics and biochemical strategies are being enhanced by the ever-expanding scale of omics technologies. An alternative approach to consider are the prospects for inducing change in plant metabolism using exogenously supplied chemical ligands. Cellulose biosynthesis inhibitors (CBI have been identified among known herbicides, during diverse combinatorial chemical libraries screens, and natural chemical screens from microbial agents. In this review, we summarize the current knowledge of the inhibitory effects of CBIs and further group them by how they influence fluorescently tagged cellulose synthase A (CESA proteins. Additional attention is paid to the continuing development of the CBI toolbox to explore the cell biology and genetic mechanisms underpinning effector molecule activity.

  9. Tetrahydrobiopterin biosynthesis, utilization and pharmacological effects.

    Science.gov (United States)

    Werner-Felmayer, G; Golderer, G; Werner, E R

    2002-04-01

    Tetrahydrobiopterin (H4-biopterin) is an essential cofactor of a set of enzymes that are of central metabolic importance, i.e. the hydroxylases of the three aromatic amino acids phenylalanine, tyrosine, and tryptophan, of ether lipid oxidase, and of the three nitric oxide synthase (NOS) isoenzymes. As a consequence, H4-biopterin plays a key role in a vast number of biological processes and pathological states associated with neurotransmitter formation, vasorelaxation, and immune response. In mammals, its biosynthesis is controlled by hormones, cytokines and certain immune stimuli. This review aims to summarize recent developments concerning regulation of H4-biopterin biosynthetic and regulatory enzymes and pharmacological effects of H4-biopterin in various conditions, e.g. endothelial dysfunction or apoptosis of neuronal cells. Also, approaches towards gene therapy of diseases like the different forms of phenylketonuria or of Parkinson's disease are reviewed. Additional emphasis is given to H4-biopterin biosynthesis and function in non-mammalian species such as fruit fly, zebra fish, fungi, slime molds, the bacterium Nocardia as well as to the parasitic protozoan genus of Leishmania that is not capable of pteridine biosynthesis but has evolved a sophisticated salvage network for scavenging various pteridine compounds, notably folate and biopterin.

  10. Exopolysaccharide biosynthesis by Lactobacillus helveticus ATCC 15807.

    Science.gov (United States)

    Torino, M I; Mozzi, F; Font de Valdez, G

    2005-08-01

    Exopolysaccharide (EPS) production and the activities of the enzymes involved in sugar nucleotide biosynthesis in Lactobacillus helveticus ATCC 15807 under controlled pH conditions were investigated. Batch fermentations using lactose as energy source showed higher EPS synthesis by L. helveticus ATCC 15807 at pH 4.5 with respect to pH 6.2, the enzyme alpha-phosphoglucomutase (alpha-PGM) being correlated with both total and specific EPS production. When glucose was used as carbon source instead of lactose, the lower EPS synthesis obtained was linked to a decrease in alpha-PGM and galactose 1-phosphate-uridyltransferase (GalT) activities, the reduction of the latter being more pronounced. Higher EPS production by L. helveticus ATCC 15807 at the acidic constant pH of 4.5 requires that both alpha-PGM and GalT activities are high. These enzymes are needed to synthesize UDP-glucose and UDP-galactose for supplying the corresponding monomers for EPS biosynthesis. Although differences are observed in EPS production by this strain regarding the energy source (lactose or glucose), the monomeric composition of the polymers produced is independent of the carbohydrate used. The obtained results contribute to a better understanding of the physiological factors that affect EPS biosynthesis by lactobacilli, which could help in the correct handling of the fermentation parameters within the fermented dairy industry.

  11. Lipopolysaccharide Structure and Biosynthesis in Helicobacter pylori.

    Science.gov (United States)

    Li, Hong; Liao, Tingting; Debowski, Aleksandra W; Tang, Hong; Nilsson, Hans-Olof; Stubbs, Keith A; Marshall, Barry J; Benghezal, Mohammed

    2016-12-01

    This review covers the current knowledge and gaps in Helicobacter pylori lipopolysaccharide (LPS) structure and biosynthesis. H. pylori is a Gram-negative bacterium which colonizes the luminal surface of the human gastric epithelium. Both a constitutive alteration of the lipid A preventing TLR4 elicitation and host mimicry of the Lewis antigen decorated O-antigen of H. pylori LPS promote immune escape and chronic infection. To date, the complete structure of H. pylori LPS is not available, and the proposed model is a linear arrangement composed of the inner core defined as the hexa-saccharide (Kdo-LD-Hep-LD-Hep-DD-Hep-Gal-Glc), the outer core composed of a conserved trisaccharide (-GlcNAc-Fuc-DD-Hep-) linked to the third heptose of the inner core, the glucan, the heptan and a variable O-antigen, generally consisting of a poly-LacNAc decorated with Lewis antigens. Although the glycosyltransferases (GTs) responsible for the biosynthesis of the H. pylori O-antigen chains have been identified and characterized, there are many gaps in regard to the biosynthesis of the core LPS. These limitations warrant additional mutagenesis and structural studies to obtain the complete LPS structure and corresponding biosynthetic pathway of this important gastric bacterium. © 2016 John Wiley & Sons Ltd.

  12. De novo Sequencing and Analysis of Lemongrass Transcriptome Provides First Insights into the Essential Oil Biosynthesis of Aromatic Grasses

    Directory of Open Access Journals (Sweden)

    Seema Meena

    2016-07-01

    Full Text Available Aromatic grasses of the genus Cymbopogon (Poaceae family represent unique group of plants that produce diverse composition of monoterpene rich essential oils, which have great value in flavour, fragrance, cosmetic and aromatherapy industries. Despite the commercial importance of these natural aromatic oils, their biosynthesis at the molecular level remains unexplored. As the first step towards understanding the essential oil biosynthesis, we performed de novo transcriptome assembly and analysis of C. flexuosus (lemongrass by employing Illumina sequencing. Mining of transcriptome data and subsequent phylogenetic analysis led to identification of terpene synthases (TPS, pyrophosphatases (PPase, alcohol dehydrogenases (ADH, aldo-keto reductases (AKR, carotenoid cleavage dioxygenases (CCD, alcohol acetyltransferases (AAT and aldehyde dehydrogenases (ALDH, which are potentially involved in essential oil biosynthesis. Comparative essential oil profiling and mRNA expression analysis in three Cymbopogon species (C. flexuosus, aldehyde type; C. martinii, alcohol type; and C. winterianus, intermediate type with varying essential oil composition indicated the involvement of identified candidate genes in the formation of alcohols, aldehydes and acetates. Molecular modeling and docking further supported the role of identified enzymes in aroma formation in Cymbopogon. Also, simple sequence repeats (SSRs were found in the transcriptome with many linked to terpene pathway genes including the genes potentially involved in aroma biosynthesis. This work provides the first insights into the essential oil biosynthesis of aromatic grasses, and the identified candidate genes and markers can be a great resource for biotechnological and molecular breeding approaches to modulate the essential oil composition.

  13. De Novo Sequencing and Analysis of Lemongrass Transcriptome Provide First Insights into the Essential Oil Biosynthesis of Aromatic Grasses.

    Science.gov (United States)

    Meena, Seema; Kumar, Sarma R; Venkata Rao, D K; Dwivedi, Varun; Shilpashree, H B; Rastogi, Shubhra; Shasany, Ajit K; Nagegowda, Dinesh A

    2016-01-01

    Aromatic grasses of the genus Cymbopogon (Poaceae family) represent unique group of plants that produce diverse composition of monoterpene rich essential oils, which have great value in flavor, fragrance, cosmetic, and aromatherapy industries. Despite the commercial importance of these natural aromatic oils, their biosynthesis at the molecular level remains unexplored. As the first step toward understanding the essential oil biosynthesis, we performed de novo transcriptome assembly and analysis of C. flexuosus (lemongrass) by employing Illumina sequencing. Mining of transcriptome data and subsequent phylogenetic analysis led to identification of terpene synthases, pyrophosphatases, alcohol dehydrogenases, aldo-keto reductases, carotenoid cleavage dioxygenases, alcohol acetyltransferases, and aldehyde dehydrogenases, which are potentially involved in essential oil biosynthesis. Comparative essential oil profiling and mRNA expression analysis in three Cymbopogon species (C. flexuosus, aldehyde type; C. martinii, alcohol type; and C. winterianus, intermediate type) with varying essential oil composition indicated the involvement of identified candidate genes in the formation of alcohols, aldehydes, and acetates. Molecular modeling and docking further supported the role of identified protein sequences in aroma formation in Cymbopogon. Also, simple sequence repeats were found in the transcriptome with many linked to terpene pathway genes including the genes potentially involved in aroma biosynthesis. This work provides the first insights into the essential oil biosynthesis of aromatic grasses, and the identified candidate genes and markers can be a great resource for biotechnological and molecular breeding approaches to modulate the essential oil composition.

  14. Alkene hydrogenation activity of enoate reductases for an environmentally benign biosynthesis of adipic acid.

    Science.gov (United States)

    Joo, Jeong Chan; Khusnutdinova, Anna N; Flick, Robert; Kim, Taeho; Bornscheuer, Uwe T; Yakunin, Alexander F; Mahadevan, Radhakrishnan

    2017-02-01

    Adipic acid, a precursor for Nylon-6,6 polymer, is one of the most important commodity chemicals, which is currently produced from petroleum. The biosynthesis of adipic acid from glucose still remains challenging due to the absence of biocatalysts required for the hydrogenation of unsaturated six-carbon dicarboxylic acids to adipic acid. Here, we demonstrate the first enzymatic hydrogenation of 2-hexenedioic acid and muconic acid to adipic acid using enoate reductases (ERs). ERs can hydrogenate 2-hexenedioic acid and muconic acid producing adipic acid with a high conversion rate and yield in vivo and in vitro . Purified ERs exhibit a broad substrate spectrum including aromatic and aliphatic 2-enoates and a significant oxygen tolerance. The discovery of the hydrogenation activity of ERs contributes to an understanding of the catalytic mechanism of these poorly characterized enzymes and enables the environmentally benign biosynthesis of adipic acid and other chemicals from renewable resources.

  15. Biosynthesis and biotransformation of bile acids

    Directory of Open Access Journals (Sweden)

    Šarenac Tanja M.

    2017-01-01

    Full Text Available Bile acids are steroidal compounds, which contain 24 carbon atoms. They can be classified into two major groups: primary and secondary. The most abundant bile acids: The primary bile acids include cholic acid and chenodeoxycholic acid, while the major secondary bile acids are deoxycholic acid and litocholic acid. Bile acids are important physiological agents for intestinal absorption of nutrients and are used for biliary lipid secretion, toxic metabolites and xenobiotics. The aim of this paper is to analyze biosynthesis and biotransformation of bile acids, as preparation for practical usage in laboratory and clinical conditions. Topic: Biosynthesis and biotransformation of bile acids: The biosynthesis of bile acids is the dominant metabolic pathway for catabolism of cholesterol in humans. The classical route of biosynthesis of bile acids is embarking on the conversion of cholesterol into 7α-hydroxycholesterol using enzyme 7α-cholesterol hydroxylase (CYP7A1. This enzyme is one of the microsomal cytochrome P450 enzyme is localized exclusively in the liver. Classical road is the main road in the biosynthesis of bile acids, and its total contribution amounts to 90% for people, and 75% in mice. CYP 7A1 enzyme is considered to be sensitive to the inhibition of carbon monoxide, and the condition for the effect of NADPH, the oxygen, lecithin, and the NADPH-cytochrome P450 reductase. Bile acids are important signaling molecules and metabolic controls which activate the nuclear receptor and the G protein-coupled receptors (GPCR, a signaling lipid regulation of the liver, glucose and energy homeostasis. Also, bile acids maintain metabolic homeostasis. Biotransformation of bile acids: The conversion of cholesterol into bile acids just important for maintenance of cholesterol homeostasis, but also to prevent the accumulation of cholesterol, triglycerides and toxic metabolites as well as violations of the liver and other organs. Enterohepatic circulation of

  16. Photosynthesis and substrate supply for isoprene biosynthesis in poplar leaves

    Science.gov (United States)

    Magel, E.; Mayrhofer, S.; Müller, A.; Zimmer, I.; Hampp, R.; Schnitzler, J.-P.

    Gray poplar leaves emit high amounts of isoprene. In this context, we investigated the degree to which photosynthesis delivers necessary precursors for chloroplast isoprene biosynthesis, and whether this energy-consuming pathway could be involved in protecting the photosynthetic electron transport system. Such protection could result from consumption of a surplus in ATP and NADPH, generated under constricted net assimilation caused by high leaf temperatures and high light intensities. During the course of the day triose phosphate (TP) and dimethylallyl diphosphate (DMADP) concentrations showed pronounced diurnal variations closely related to net assimilation and isoprene emission rates, while other variables, e.g. energy (ATP/ADP) and redox (NADPH/NADP) ratio, as well as phosphoenolpyruvate (PEP) and pyruvate strongly scattered related to changing temperature and light intensities. Intra-day positive correlations were found mainly between leaf concentrations of TP and DMADP, and sucrose, ATP/ADP ratio and net assimilation rates. Under non-saturating light (200-400 μmol photons m -2 s -1), leaf DMADP pools were positively correlated mainly with PEP, starch, and fructose 2,6-bisphosphate (F26BP). Under saturating light, correlations improved and additionally involved sucrose, TP, and the ratio of NADPH/NADP. Study of temperature response curves showed that net assimilation and isoprene emission were negatively correlated to each other. This disconnection was mostly visible by the transient change of DMADP contents with maximum levels at 25 °C. At higher temperatures, declining pools of DMADP, TP and pyruvate indicated that DMADP consumption overcompensated DMADP production resulting in highest isoprene emission rates at declining pool sizes of precursors. In parallel to the reduction of net assimilation increases of NADPH/NADP and ATP/ADP ratios also portended that the MEP pathway dissipates a surplus of ATP and NADPH which cannot be used for carbon reduction under

  17. Heat stress differentially modifies ethylene biosynthesis and signaling in pea floral and fruit tissues.

    Science.gov (United States)

    Savada, Raghavendra P; Ozga, Jocelyn A; Jayasinghege, Charitha P A; Waduthanthri, Kosala D; Reinecke, Dennis M

    2017-10-01

    Ethylene biosynthesis is regulated in reproductive tissues in response to heat stress in a manner to optimize resource allocation to pollinated fruits with developing seeds. High temperatures during reproductive development are particularly detrimental to crop fruit/seed production. Ethylene plays vital roles in plant development and abiotic stress responses; however, little is known about ethylene's role in reproductive tissues during development under heat stress. We assessed ethylene biosynthesis and signaling regulation within the reproductive and associated tissues of pea during the developmental phase that sets the stage for fruit-set and seed development under normal and heat-stress conditions. The transcript abundance profiles of PsACS [encode enzymes that convert S-adenosyl-L-methionine to 1-aminocyclopropane-1-carboxylic acid (ACC)] and PsACO (encode enzymes that convert ACC to ethylene), and ethylene evolution were developmentally, environmentally, and tissue-specifically regulated in the floral/fruit/pedicel tissues of pea. Higher transcript abundance of PsACS and PsACO in the ovaries, and PsACO in the pedicels was correlated with higher ethylene evolution and ovary senescence and pedicel abscission in fruits that were not pollinated under control temperature conditions. Under heat-stress conditions, up-regulation of ethylene biosynthesis gene expression in pre-pollinated ovaries was also associated with higher ethylene evolution and lower retention of these fruits. Following successful pollination and ovule fertilization, heat-stress modified PsACS and PsACO transcript profiles in a manner that suppressed ovary ethylene evolution. The normal ethylene burst in the stigma/style and petals following pollination was also suppressed by heat-stress. Transcript abundance profiles of ethylene receptor and signaling-related genes acted as qualitative markers of tissue ethylene signaling events. These data support the hypothesis that ethylene biosynthesis is

  18. Green biosynthesis of silver nanoparticles using Curcuma longa tuber powder

    Directory of Open Access Journals (Sweden)

    Shameli K

    2012-10-01

    Full Text Available Kamyar Shameli,1,2 Mansor Bin Ahmad,1 Ali Zamanian,2 Parvanh Sangpour,2 Parvaneh Shabanzadeh,3 Yadollah Abdollahi,4 Mohsen Zargar51Department of Chemistry, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Materials and Energy Research Center, Karaj, Iran; 3Department of Mathematics, 4Advanced Materials and Nanotechnology Laboratory, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 5Department of Biology, Islamic Azad University, Qom, IranAbstract: Green synthesis of noble metal nanoparticles is a vastly developing area of research. Metallic nanoparticles have received great attention from chemists, physicists, biologists, and engineers who wish to use them for the development of a new-generation of nanodevices. In this study, silver nanoparticles were biosynthesized from aqueous silver nitrate through a simple and eco-friendly route using Curcuma longa tuber-powder extracts, which acted as a reductant and stabilizer simultaneously. Characterizations of nanoparticles were done using different methods, which included ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier-transform infrared spectroscopy. The ultraviolet-visible spectrum of the aqueous medium containing silver nanoparticles showed an absorption peak at around 415 nm. Transmission electron microscopy showed that mean diameter and standard deviation for the formation of silver nanoparticles was 6.30 ± 2.64 nm. Powder X-ray diffraction showed that the particles are crystalline in nature, with a face-centered cubic structure. The most needed outcome of this work will be the development of value-added products from C. longa for biomedical and nanotechnology-based industries.Keywords: silver nanoparticles, Curcuma longa, biosynthesis, green synthesis, transmission electron microscopy

  19. Innovative Resources for Education and Public Information: Electronic Services, Data and Information from NASA's Hubble Space Telescope and Other NASA Missions.

    Science.gov (United States)

    Christian, Carol A.

    The Space Telescope Science Institute (STScI), which supports the operation of the Hubble Space Telescope, is actively investigating and supporting innovative and experimental methods for improving science and math education content. The educational resources on the World Wide Web are derived from the latest data, scientific results, and advances…

  20. How Students Learn: Ways of Thinking about "Good Learning" in HE. EDNER (Formative Evaluation of the Distributed National Electronic Resource) Project. Issues Paper.

    Science.gov (United States)

    Manchester Metropolitan Univ. (England).

    This issues paper, one of a series of eight, is intended to distill formative evaluation questions on topics that are central to the development of the higher and further education information environment in the United Kingdom. The topic of this first issues paper is a conceptual framework that can help members of a project (information resource)…

  1. Rapid biosynthesis of silver nanoparticles using the marine red alga Laurencia catarinensis and their characterization

    Directory of Open Access Journals (Sweden)

    Neveen Abdel-Raouf

    2018-03-01

    Full Text Available Bio-synthesis of AgNPs (silver nanoparticles by using of the dry and solvent extract of red marine alga Laurencia catarinensis was conducted in the present work. Characterizations of the formed AgNPs was approved by UV–Visible Spectroscopy, Transmission Electron Microscopy, Dynamic Light Scattering and finally by Fourier Transform Infrared spectroscopy. We achieved the synthesis of AgNPs by the reduction of aqueous solutions of AgNO3 with the powder and extract of Laurencia catarinensis. Bio-synthesis of Ag nanoparticles was confirmed by visual inspection. The obtained algal nanoparticles were characterized by highly stable formation, short time of the biogenic process (2 min-3 h, small size (39.41–77.71 nm with several shapes (spherical, triangular, rectangle, polyhedral and hexagonal.

  2. 大學圖書館電子資源之需求分析與行銷策略之研究 A Study of Demands Analysis and Marketing Strategy of Electronic Resources in University Library

    Directory of Open Access Journals (Sweden)

    Huang-Yu Liu

    2008-03-01

    Full Text Available 電子資源的出現,使得知識載體有了新的突破,提高了使用者的便利性與即時性。對於圖書館而言,如何使電子資源的使用效益達到最高,必須思考一套有效的行銷策略。電子資源行銷概念應以讀者為導向,尊重讀者的資訊需求,並利用各種宣傳技巧,行銷電子資源,使圖書館能提供更完善的服務。本研究之目的旨在探討讀者的使用需求及電子資源的推廣策略,以獲致最有效益的行銷方式。研究對象以開南大學日間部四學院(商學院、運輸觀光學院、資訊學院、人文社會學院)學生為樣本,佐以缺口分析模型為分析架構,藉以找出個案中讀者/學生對於電子資源使用的真實需求,並進而歸納出提供服務的大學圖書館在其推廣或行銷服務上可有的因應策略。The emergence of electronic resources has made new breakthrough in knowledge carriers because of their ease of use, instant availability, and the characteristic of no time and space constraints. For public libraries to achieve maximum efficiency in its electronic resources, it is necessary to seek the most effective marketing strategies. Therefore, the marketing concept of the electronic resources should be reader oriented, such as respecting and understanding library user’s information needs. Libraries also need to utilize various media and techniques to market the electronic resources, so that more comprehensive services and experiences can be provided to readers. The purpose of this study is to investigate library user’s needs and promotion strategies of electronic resources in order to identify the most effective ways of marketing. This study focuses on the students of the four colleges (College of Business, College of Tourism, College of Information, and College of Humanities and Social Science in Kainan University as subjects in the survey questionnaire. It uses the Gap Analysis

  3. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

  4. Application of electronic learning tools for training of specialists in the field of information technologies for enterprises of mineral resources sector

    Directory of Open Access Journals (Sweden)

    Е. В. Катунцов

    2017-08-01

    Full Text Available The article shows the advantages of using modern electronic learning tools in the training of specialists for the mineral and raw materials complex and considers the basic principles of organizing training using these tools. The experience of using electronic learning tools using foreign teaching materials and involving foreign professors is described. A special attention is given to the electronic learning environment of the Cisco Networking Academy – Cisco NetAcad. The experience of teaching at the Networking Academy of the Saint-Petersburg Mining University is described. Details are given to modern virtual environments for laboratory work, such as Cisco Packet Tracer, GNS3 and Emulated Virtual Environment. The experience of using electronic learning technologies at the University of Economics of Bratislava is considered. It actively cooperates with a number of universities of other countries, such as the University of International Business (Almaty, the Eurasian National University named after LN Gumilyov (Astana and the Institute of Social and Humanitarian Knowledge (Kazan.

  5. The Biosynthesis of Capuramycin-type Antibiotics

    Science.gov (United States)

    Cai, Wenlong; Goswami, Anwesha; Yang, Zhaoyong; Liu, Xiaodong; Green, Keith D.; Barnard-Britson, Sandra; Baba, Satoshi; Funabashi, Masanori; Nonaka, Koichi; Sunkara, Manjula; Morris, Andrew J.; Spork, Anatol P.; Ducho, Christian; Garneau-Tsodikova, Sylvie; Thorson, Jon S.; Van Lanen, Steven G.

    2015-01-01

    A-500359s, A-503083s, and A-102395 are capuramycin-type nucleoside antibiotics that were discovered using a screen to identify inhibitors of bacterial translocase I, an essential enzyme in peptidoglycan cell wall biosynthesis. Like the parent capuramycin, A-500359s and A-503083s consist of three structural components: a uridine-5′-carboxamide (CarU), a rare unsaturated hexuronic acid, and an aminocaprolactam, the last of which is substituted by an unusual arylamine-containing polyamide in A-102395. The biosynthetic gene clusters for A-500359s and A-503083s have been reported, and two genes encoding a putative non-heme Fe(II)-dependent α-ketoglutarate:UMP dioxygenase and an l-Thr:uridine-5′-aldehyde transaldolase were uncovered, suggesting that C–C bond formation during assembly of the high carbon (C6) sugar backbone of CarU proceeds from the precursors UMP and l-Thr to form 5′-C-glycyluridine (C7) as a biosynthetic intermediate. Here, isotopic enrichment studies with the producer of A-503083s were used to indeed establish l-Thr as the direct source of the carboxamide of CarU. With this knowledge, the A-102395 gene cluster was subsequently cloned and characterized. A genetic system in the A-102395-producing strain was developed, permitting the inactivation of several genes, including those encoding the dioxygenase (cpr19) and transaldolase (cpr25), which abolished the production of A-102395, thus confirming their role in biosynthesis. Heterologous production of recombinant Cpr19 and CapK, the transaldolase homolog involved in A-503083 biosynthesis, confirmed their expected function. Finally, a phosphotransferase (Cpr17) conferring self-resistance was functionally characterized. The results provide the opportunity to use comparative genomics along with in vivo and in vitro approaches to probe the biosynthetic mechanism of these intriguing structures. PMID:25855790

  6. Heme biosynthesis and its regulation : Toward understanding and improvement of heme biosynthesis in filamentous fungi.

    NARCIS (Netherlands)

    S. de Weert; P.J. Punt; Christien Lokman; C.A. van den Hondel; A.C. Franken; A.F. Ram

    2011-01-01

    Heme biosynthesis in fungal host strains has acquired considerable interest in relation to the production of secreted heme-containing peroxidases. Class II peroxidase enzymes have been suggested as eco-friendly replacements of polluting chemical processes in industry. These peroxidases are naturally

  7. Heme biosynthesis and its regulation: Towards understanding and improvement of heme biosynthesis in filamentous fungi

    NARCIS (Netherlands)

    Franken, A.C.W.; Lokman, B.C.; Ram, A.F.J.; Punt, P.J.; Hondel, C.A.M.J.J. van den; Weert, S. de

    2011-01-01

    Heme biosynthesis in fungal host strains has acquired considerable interest in relation to the production of secreted heme-containing peroxidases. Class II peroxidase enzymes have been suggested as eco-friendly replacements of polluting chemical processes in industry. These peroxidases are naturally

  8. Unedoside derivatives in Nuxia and their biosynthesis

    DEFF Research Database (Denmark)

    Jensen, Søren Rosendal; Ravnkilde, Lene; Schripsema, Jan

    1998-01-01

    An investigation of two species of Nuxia showed that this genus is characterized by the presence of the eight-carbon iridoid glucoside unedoside and/or its derivatives. From N. floribunda unedoside, nuxioside (6-O-alpha-L-rhamnopyranosyl-unedoside) and 2 "-acetyl-3 "-cinnamoyl-nuxioside were...... isolated, while from N. oppositifolia 2 "-acetyl-3 "-benzoyl-nuxioside was obtained. Both plants contained verbascoside. The biosynthesis of unedoside in N. floribunda was investigated and deoxyloganic acid was found to be a precursor, similar to wh;lt was found for the eight-carbon iridoids in Thunbergia...

  9. Developing New Antibiotics with Combinatorial Biosynthesis

    Science.gov (United States)

    Pohl, Nicola L.

    2000-11-01

    Polyketide synthases (PKSs), a class of enzymes found in soil bacteria that produce antibiotics such as erythromycin, string together acetate units using basic organic reactions. The manipulation of the sequence of these reactions at the genetic level has resulted in an alteration of the corresponding chemical structure of the antibiotic produced by the bacteria. This process, called combinatorial biosynthesis, allows the generation of many presently unknown complex structures that can be tested for antibacterial activity, thereby contributing to the race against antibiotic-resistant infectious bacteria.

  10. Biosynthesis of silver nanoparticles using Saccharomyces cerevisiae.

    Science.gov (United States)

    Korbekandi, Hassan; Mohseni, Soudabeh; Mardani Jouneghani, Rasoul; Pourhossein, Meraj; Iravani, Siavash

    2016-01-01

    The objectives of this study were the biosynthesis of silver nanoparticles (NPs) by biotransformations using Saccharomyces cerevisiae and analysis of the sizes and shapes of the NPs produced. Dried and freshly cultured S. cerevisiae were used as the biocatalyst. Dried yeast synthesized few NPs, but freshly cultured yeast produced a large amount of them. Silver NPs were spherical, 2-20 nm in diameter, and the NPs with the size of 5.4 nm were the most frequent ones. NPs were seen inside the cells, within the cell membrane, attached to the cell membrane during the exocytosis, and outside of the cells.

  11. Positive Perceptions of Access to Online Library Resources Correlates with Quality and Quantity of Scholarly Publications among Finnish Academics. A Review of: Vakkari, Pertti. “Perceived Influence of the Use of Electronic Information Resources on Scholarly Work and Publication Productivity.” Journal of the American Society for Information Science and Technology 59.4 (Feb. 15, 2008: 602-12.

    Directory of Open Access Journals (Sweden)

    Scott Marsalis

    2008-12-01

    Full Text Available Objective – To investigate the relationship between academics’ use of library electronic resources and their opinions regarding how these resources have impacted their work, and to investigate the association between this perceived influence and publication productivity during the previous two years.Design – Two specific questions added to an annual online user-survey questionnaire; additional data mined from surveySetting – Twenty-two Finnish Universities served by FinELib, the Finnish Electronic Library.Subjects – Seven hundred and sixty seven academic staff and full-time doctoral students.Methods – A questionnaire was posted in April 2007 on FinELib’s homepage and advertised on each university library’s mainpage, and focused on respondents’ experience in the previous two years. Participants selected answers either from a list of category choices, or, when measuring perceptions, by rating agreement with statements along a four-point scale. Controlled variables measured were the respondents’ academic position, their discipline, membership in a research group, whether their literature use was discipline-specific or interdisciplinary, and their perception of the availability online of the relevant core literature. The independent variable measured was the scholars’ perception of the impact of the use of electronic library resources on their work. The dependent variable measured was the scholars’ self-reported publications in the two years preceding the survey.Main Results – Participants reported a positive impact on the efficiency of their work, most strongly in areas of ease of access, with lesser impacts in the range of materials available to them and the ease with which they can keep up-to-date in their field. To a lesser extent, the scholars perceived a positive impact on the quality of their work. Upon analysis, the study found that access to online library resources improved scholars’ work by the interconnected

  12. Fusion of ferredoxin and cytochrome P450 enables direct light-driven biosynthesis

    DEFF Research Database (Denmark)

    Mellor, Silas Busck; Nielsen, Agnieszka Janina Zygadlo; Burow, Meike

    2016-01-01

    , and their requirement for NADPH as a source of reducing power. We recently demonstrated targeting and insertion of plant P450s into the photosynthetic membrane, and photosynthesis-driven, NADPH-independent P450 catalytic activity mediated by the electron carrier protein ferredoxin. Here we report the fusion...... of ferredoxin with P450 CYP79A1 from the model plant Sorghum bicolor, which catalyzes the initial step in the pathway leading to biosynthesis of the cyanogenic glucoside dhurrin. Fusion with ferredoxin allows CYP79A1 to obtain electrons for catalysis by interacting directly with photosystem I. Furthermore......, electrons captured by the fused ferredoxin moiety are directed more effectively towards P450 catalytic activity, making the fusion better able to compete with endogenous electron sinks coupled to metabolic pathways. The P450-ferredoxin fusion enzyme obtains reducing power solely from its fused ferredoxin...

  13. Electronic collection management

    CERN Document Server

    Mcginnis, Suzan D

    2013-01-01

    Build and manage your collection of digital resources with these successful strategies! This comprehensive volume is a practical guide to the art and science of acquiring and organizing electronic resources. The collections discussed here range in size from small college libraries to large research libraries, but all are facing similar problems: shrinking budgets, increasing demands, and rapidly shifting formats. Electronic Collection Management offers new ideas for coping with these issues. Bringing together diverse aspects of collection development, Electronic Collection

  14. BIOSYNTHESIS AND PROPERTIES OF ANTIBIOTIC BATUMIN

    Directory of Open Access Journals (Sweden)

    V. V. Klochko

    2014-12-01

    Full Text Available Biosynthesis of antistaphylococcal antibiotic batumin under periodic conditions of Pseudomonas batumici growth has been studied. Antibiotic synthesis in fermenter occurred across the culture growth and achieved its maximal value after 50–55 hours. The active oxygen utilization by the producing strain was observed during 20–55 hours of fermentation with maximum after 40–45 hours. Antibiotic yield was 175–180 mg/l and depended on intensity of aeration. contrast to «freshly isolated» antibiotic after fermentation the long-term kept batumin has shown two identical by molecular mass peaks according to the chromato-mass spectrometric analysis. Taking into account of batumin molecule structure the conclusion has been made that the most probable isomerization type is keto-enolic tautomerism. At the same time batumin is diastereoisomer of kalimantacin A which has the same chemical structure. The optic rotation angle is [α]d25 = +56.3° for kalimantacin and [α]d25 = –13.5° for batumin. The simultaneous P. batumici growth and antibiotic biosynthesis and the ability of this molecule to optical isomerisation and keto-enolic forms formation allow us to suppose that batumin plays a certain role in metabolism of the producing strain.

  15. Essences in Metabolic Engineering of Lignan Biosynthesis

    Directory of Open Access Journals (Sweden)

    Honoo Satake

    2015-05-01

    Full Text Available Lignans are structurally and functionally diverse phytochemicals biosynthesized in diverse plant species and have received wide attentions as leading compounds of novel drugs for tumor treatment and healthy diets to reduce of the risks of lifestyle-related non-communicable diseases. However, the lineage-specific distribution and the low-amount of production in natural plants, some of which are endangered species, hinder the efficient and stable production of beneficial lignans. Accordingly, the development of new procedures for lignan production is of keen interest. Recent marked advances in the molecular and functional characterization of lignan biosynthetic enzymes and endogenous and exogenous factors for lignan biosynthesis have suggested new methods for the metabolic engineering of lignan biosynthesis cascades leading to the efficient, sustainable, and stable lignan production in plants, including plant cell/organ cultures. Optimization of light conditions, utilization of a wide range of elicitor treatments, and construction of transiently gene-transfected or transgenic lignan-biosynthesizing plants are mainly being attempted. This review will present the basic and latest knowledge regarding metabolic engineering of lignans based on their biosynthetic pathways and biological activities, and the perspectives in lignan production via metabolic engineering.

  16. Fatty acid biosynthesis in pea root plastids

    International Nuclear Information System (INIS)

    Stahl, R.J.; Sparace, S.A.

    1989-01-01

    Fatty acid biosynthesis from [1- 14 C]acetate was optimized in plastids isolated from primary root tips of 7-day-old germinating pea seeds. Fatty acid synthesis was maximum at approximately 80 nmoles/hr/mg protein in the presence of 200 μM acetate, 0.5 mM each of NADH, NADPH and CoA, 6 mM each of ATP and MgCl 2 , 1 mM each of the MnCl 2 and glycerol-3-phosphate, 15 mM KHCO 3 , and 0.1M Bis-tris-propane, pH 8.0 incubated at 35C. At the standard incubation temperature of 25C, fatty acid synthesis was linear from up to 6 hours with 80 to 100 μg/mL plastid protein. ATP and CoA were absolute requirements, whereas KHCO 3 , divalent cations and reduced nucleotides all improved activity by 80 to 85%. Mg 2+ and NADH were the preferred cation and nucleotide, respectively. Dithiothreitol and detergents were generally inhibitory. The radioactive products of fatty acid biosynthesis were approximately 33% 16:0, 10% 18:0 and 56% 18:1 and generally did not vary with increasing concentrations of each cofactor

  17. Benzylisoquinoline alkaloid biosynthesis in opium poppy.

    Science.gov (United States)

    Beaudoin, Guillaume A W; Facchini, Peter J

    2014-07-01

    Opium poppy (Papaver somniferum) is one of the world's oldest medicinal plants and remains the only commercial source for the narcotic analgesics morphine, codeine and semi-synthetic derivatives such as oxycodone and naltrexone. The plant also produces several other benzylisoquinoline alkaloids with potent pharmacological properties including the vasodilator papaverine, the cough suppressant and potential anticancer drug noscapine and the antimicrobial agent sanguinarine. Opium poppy has served as a model system to investigate the biosynthesis of benzylisoquinoline alkaloids in plants. The application of biochemical and functional genomics has resulted in a recent surge in the discovery of biosynthetic genes involved in the formation of major benzylisoquinoline alkaloids in opium poppy. The availability of extensive biochemical genetic tools and information pertaining to benzylisoquinoline alkaloid metabolism is facilitating the study of a wide range of phenomena including the structural biology of novel catalysts, the genomic organization of biosynthetic genes, the cellular and sub-cellular localization of biosynthetic enzymes and a variety of biotechnological applications. In this review, we highlight recent developments and summarize the frontiers of knowledge regarding the biochemistry, cellular biology and biotechnology of benzylisoquinoline alkaloid biosynthesis in opium poppy.

  18. Molecular Regulation of Antibiotic Biosynthesis in Streptomyces

    Science.gov (United States)

    Liu, Gang; Chandra, Govind; Niu, Guoqing

    2013-01-01

    SUMMARY Streptomycetes are the most abundant source of antibiotics. Typically, each species produces several antibiotics, with the profile being species specific. Streptomyces coelicolor, the model species, produces at least five different antibiotics. We review the regulation of antibiotic biosynthesis in S. coelicolor and other, nonmodel streptomycetes in the light of recent studies. The biosynthesis of each antibiotic is specified by a large gene cluster, usually including regulatory genes (cluster-situated regulators [CSRs]). These are the main point of connection with a plethora of generally conserved regulatory systems that monitor the organism's physiology, developmental state, population density, and environment to determine the onset and level of production of each antibiotic. Some CSRs may also be sensitive to the levels of different kinds of ligands, including products of the pathway itself, products of other antibiotic pathways in the same organism, and specialized regulatory small molecules such as gamma-butyrolactones. These interactions can result in self-reinforcing feed-forward circuitry and complex cross talk between pathways. The physiological signals and regulatory mechanisms may be of practical importance for the activation of the many cryptic secondary metabolic gene cluster pathways revealed by recent sequencing of numerous Streptomyces genomes. PMID:23471619

  19. Biosynthesis of nanoparticles using microbes- a review.

    Science.gov (United States)

    Hulkoti, Nasreen I; Taranath, T C

    2014-09-01

    The biosynthesis of nanoparticles by microorganism is a green and eco-friendly technology. This review focuses on the use of consortium of diverse microorganisms belonging to both prokaryotes and eukaryotes for the synthesis of metallic nanoparticles viz. silver, gold, platinum, zirconium, palladium, iron, cadmium and metal oxides such as titanium oxide, zinc oxide, etc. These microorganisms include bacteria, actinomycetes, fungi and algae. The synthesis of nanoparticles may be intracellular or extracellular. The several workers have reported that NADH dependent nitrate reductase enzyme plays a vital role in the conversion of metallic ions to nanoparticles. The FTIR study reveals that diverse biomolecules viz. carboxyl group, primary and secondary amines, amide I, II, and III bands etc serve as a tool for bioreduction and capping agents there by offering stability to particles by preventing agglomeration and growth. The size and shape of the nanoparticles vary with the organism employed and conditions employed during the synthesis which included pH, temperature and substrate concentration. The microorganisms provide diverse environment for biosynthesis of nanoparticles. These particles are safe and eco-friendly with a lot of applications in medicine, agriculture, cosmetic industry, drug delivery and biochemical sensors. The challenges for redressal include optimal production and minimal time to obtain desired size and shape, to enhance the stability of nanoparticles and optimization of specific microorganisms for specific application. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Comprehensive Characterization for Ginsenosides Biosynthesis in Ginseng Root by Integration Analysis of Chemical and Transcriptome

    Directory of Open Access Journals (Sweden)

    Jing-Jing Zhang

    2017-05-01

    Full Text Available Herbgenomics provides a global platform to explore the genetics and biology of herbs on the genome level. Panax ginseng C.A. Meyer is an important medicinal plant with numerous pharmaceutical effects. Previous reports mainly discussed the transcriptome of ginseng at the organ level. However, based on mass spectrometry imaging analyses, the ginsenosides varied among different tissues. In this work, ginseng root was separated into three tissues—periderm, cortex and stele—each for five duplicates. The chemical analysis and transcriptome analysis were conducted simultaneously. Gene-encoding enzymes involved in ginsenosides biosynthesis and modification were studied based on gene and molecule data. Eight widely-used ginsenosides were distributed unevenly in ginseng roots. A total of 182,881 unigenes were assembled with an N50 contig size of 1374 bp. About 21,000 of these unigenes were positively correlated with the content of ginsenosides. Additionally, we identified 192 transcripts encoding enzymes involved in two triterpenoid biosynthesis pathways and 290 transcripts encoding UDP-glycosyltransferases (UGTs. Of these UGTs, 195 UGTs (67.2% were more highly expressed in the periderm, and that seven UGTs and one UGT were specifically expressed in the periderm and stele, respectively. This genetic resource will help to improve the interpretation on complex mechanisms of ginsenosides biosynthesis, accumulation, and transportation.

  1. Biosynthesis of Polyunsaturated Fatty Acids in Marine Invertebrates: Recent Advances in Molecular Mechanisms

    Science.gov (United States)

    Monroig, Óscar; Tocher, Douglas R.; Navarro, Juan C.

    2013-01-01

    Virtually all polyunsaturated fatty acids (PUFA) originate from primary producers but can be modified by bioconversions as they pass up the food chain in a process termed trophic upgrading. Therefore, although the main primary producers of PUFA in the marine environment are microalgae, higher trophic levels have metabolic pathways that can produce novel and unique PUFA. However, little is known about the pathways of PUFA biosynthesis and metabolism in the levels between primary producers and fish that are largely filled by invertebrates. It has become increasingly apparent that, in addition to trophic upgrading, de novo synthesis of PUFA is possible in some lower animals. The unequivocal identification of PUFA biosynthetic pathways in many invertebrates is complicated by the presence of other organisms within them. These organisms include bacteria and algae with PUFA biosynthesis pathways, and range from intestinal flora to symbiotic relationships that can involve PUFA translocation to host organisms. This emphasizes the importance of studying biosynthetic pathways at a molecular level, and the continual expansion of genomic resources and advances in molecular analysis is facilitating this. The present paper highlights recent research into the molecular and biochemical mechanisms of PUFA biosynthesis in marine invertebrates, particularly focusing on cephalopod molluscs. PMID:24152561

  2. De Novo Assembly and Comparative Transcriptome Analysis Provide Insight into Lysine Biosynthesis in Toona sinensis Roem

    Directory of Open Access Journals (Sweden)

    Xia Zhang

    2016-01-01

    Full Text Available Toona sinensis Roem is a popular leafy vegetable in Chinese cuisine and is also used as a traditional Chinese medicine. In this study, leaf samples were collected from the same plant on two development stages and then used for high-throughput Illumina RNA-sequencing (RNA-Seq. 125,884 transcripts and 54,628 unigenes were obtained through de novo assembly. A total of 25,570 could be annotated with known biological functions, which indicated that the T. sinensis leaves and shoots were undergoing multiple developmental processes especially for active metabolic processes. Analysis of differentially expressed unigenes between the two libraries showed that the lysine biosynthesis was an enriched KEGG pathway, and candidate genes involved in the lysine biosynthesis pathway in T. sinensis leaves and shoots were identified. Our results provide a primary analysis of the gene expression files of T. sinensis leaf and shoot on different development stages and afford a valuable resource for genetic and genomic research on plant lysine biosynthesis.

  3. EFFECTIVE ELECTRONIC TUTORIAL

    Directory of Open Access Journals (Sweden)

    Andrei A. Fedoseev

    2014-01-01

    Full Text Available The article analyzes effective electronic tutorials creation and application based on the theory of pedagogy. Herewith the issues of necessary electronic tutorial functional, ways of the educational process organization with the use of information and communication technologies and the logistics of electronic educational resources are touched upon. 

  4. Rare cause of post-squalene disorder of cholesterol biosynthesis ...

    African Journals Online (AJOL)

    Errors of cholesterol biosynthesis represent a heterogeneous group of metabolic disorders. The aim of the authors of this article is to present a case of a patient with typical symptoms of a rare post-squalene disorder of cholesterol biosynthesis, its diagnostics and progress in neonatal period. The differential diagnosis of a ...

  5. Rapid biosynthesis of cadmium sulfide (CdS) nanoparticles using ...

    African Journals Online (AJOL)

    Rapid biosynthesis of cadmium sulfide (CdS) nanoparticles using culture supernatants of Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633 and Lactobacillus ... The process of extracellular and fast biosynthesis may help in the development of an easy and eco-friendly route for the synthesis of CdS nanoparticles.

  6. Ant trail pheromone biosynthesis is triggered by a neuropeptide hormone.

    Directory of Open Access Journals (Sweden)

    Man-Yeon Choi

    Full Text Available Our understanding of insect chemical communication including pheromone identification, synthesis, and their role in behavior has advanced tremendously over the last half-century. However, endocrine regulation of pheromone biosynthesis has progressed slowly due to the complexity of direct and/or indirect hormonal activation of the biosynthetic cascades resulting in insect pheromones. Over 20 years ago, a neurohormone, pheromone biosynthesis activating neuropeptide (PBAN was identified that stimulated sex pheromone biosynthesis in a lepidopteran moth. Since then, the physiological role, target site, and signal transduction of PBAN has become well understood for sex pheromone biosynthesis in moths. Despite that PBAN-like peptides (∼200 have been identified from various insect Orders, their role in pheromone regulation had not expanded to the other insect groups except for Lepidoptera. Here, we report that trail pheromone biosynthesis in the Dufour's gland (DG of the fire ant, Solenopsis invicta, is regulated by PBAN. RNAi knock down of PBAN gene (in subesophageal ganglia or PBAN receptor gene (in DG expression inhibited trail pheromone biosynthesis. Reduced trail pheromone was documented analytically and through a behavioral bioassay. Extension of PBAN's role in pheromone biosynthesis to a new target insect, mode of action, and behavioral function will renew research efforts on the involvement of PBAN in pheromone biosynthesis in Insecta.

  7. Metabolic engineering of ketocarotenoid biosynthesis in higher plants.

    Science.gov (United States)

    Zhu, Changfu; Naqvi, Shaista; Capell, Teresa; Christou, Paul

    2009-03-15

    Ketocarotenoids such as astaxanthin and canthaxanthin have important applications in the nutraceutical, cosmetic, food and feed industries. Astaxanthin is derived from beta-carotene by 3-hydroxylation and 4-ketolation at both ionone end groups. These reactions are catalyzed by beta-carotene hydroxylase and beta-carotene ketolase, respectively. The hydroxylation reaction is widespread in higher plants, but ketolation is restricted to a few bacteria, fungi, and some unicellular green algae. The recent cloning and characterization of beta-carotene ketolase genes in conjunction with the development of effective co-transformation strategies permitting facile co-integration of multiple transgenes in target plants provided essential resources and tools to produce ketocarotenoids in planta by genetic engineering. In this review, we discuss ketocarotenoid biosynthesis in general, and characteristics and functional properties of beta-carotene ketolases in particular. We also describe examples of ketocarotenoid engineering in plants and we conclude by discussing strategies to efficiently convert beta-carotene to astaxanthin in transgenic plants.

  8. Biosynthesis and biological functions of terpenoids in plants.

    Science.gov (United States)

    Tholl, Dorothea

    2015-01-01

    Terpenoids (isoprenoids) represent the largest and most diverse class of chemicals among the myriad compounds produced by plants. Plants employ terpenoid metabolites for a variety of basic functions in growth and development but use the majority of terpenoids for more specialized chemical interactions and protection in the abiotic and biotic environment. Traditionally, plant-based terpenoids have been used by humans in the food, pharmaceutical, and chemical industries, and more recently have been exploited in the development of biofuel products. Genomic resources and emerging tools in synthetic biology facilitate the metabolic engineering of high-value terpenoid products in plants and microbes. Moreover, the ecological importance of terpenoids has gained increased attention to develop strategies for sustainable pest control and abiotic stress protection. Together, these efforts require a continuous growth in knowledge of the complex metabolic and molecular regulatory networks in terpenoid biosynthesis. This chapter gives an overview and highlights recent advances in our understanding of the organization, regulation, and diversification of core and specialized terpenoid metabolic pathways, and addresses the most important functions of volatile and nonvolatile terpenoid specialized metabolites in plants.

  9. Biosynthesis of Gold and Silver Nanoparticles Using Extracts of Callus Cultures of Pumpkin (Cucurbita maxima).

    Science.gov (United States)

    Iyer, R Indira; Panda, Tapobrata

    2018-08-01

    The potential of callus cultures and field-grown organs of pumpkin (Cucurbita maxima) for the biosynthesis of nanoparticles of the noble metals gold and silver has been investigated. Biosynthesis of AuNPs (gold nanoparticles) and AgNPs (silver nanoparticles) was obtained with flowers of C. maxima but not with pulp and seeds. With callus cultures established in MS-based medium the biogenesis of both AuNPs and AgNPs could be obtained. At 65 °C the biogenesis of AuNPs and AgNPs by callus extracts was enhanced. The AuNPs and AgNPs have been characterized by UV-visible spectroscopy, TEM, DLS and XRD. Well-dispersed nanoparticles, which exhibited a remarkable diversity in size and shape, could be visualized by TEM. Gold nanoparticles were found to be of various shapes, viz., rods, triangles, star-shaped particles, spheres, hexagons, bipyramids, discoid particles, nanotrapezoids, prisms, cuboids. Silver nanoparticles were also of diverse shapes, viz., discoid, spherical, elliptical, triangle-like, belt-like, rod-shaped forms and cuboids. EDX analysis indicated that the AuNPs and AgNPs had a high degree of purity. The surface charges of the generated AuNPs and AgNPs were highly negative as indicated by zeta potential measurements. The AuNPs and AgNPs exhibited remarkable stability in solution for more than four months. FTIR studies indicated that biomolecules in the callus extracts were associated with the biosynthesis and stabilisation of the nanoparticles. The synthesized AgNPs could catalyse degradation of methylene blue and exhibited anti-bacterial activity against E. coli DH5α. There is no earlier report of the biosynthesis of nanoparticles by this plant species. Callus cultures of Cucurbita maxima are effective alternative resources of biomass for synthesis of nanoparticles.

  10. Nitric oxide metabolism and indole acetic acid biosynthesis cross-talk in Azospirillum brasilense SM.

    Science.gov (United States)

    Koul, Vatsala; Tripathi, Chandrakant; Adholeya, Alok; Kochar, Mandira

    2015-04-01

    Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase (nosZ), nitrous oxide reductase regulator (nosR) and nitric oxide reductase (norB) were identified in the plant-associated bacterium (PAB) Azospirillum brasilense SM. NO presence was confirmed in all overexpressing strains, while improvement in the plant growth response of these strains was mediated by increased NO and indole-3-acetic acid (IAA) levels in the strains. Electron microscopy showed random distribution to biofilm, with surface colonization of pleiomorphic Azospirilla. Quantitative IAA estimation highlighted a crucial role of nosR and norBC in regulating IAA biosynthesis. The NO quencher and donor reduced/blocked IAA biosynthesis by all strains, indicating their common regulatory role in IAA biosynthesis. Tryptophan (Trp) and l-Arginine (Arg) showed higher expression of NO genes tested, while in the case of ipdC, only Trp and IAA increased expression, while Arg had no significant effect. The highest nosR expression in SMnosR in the presence of IAA and Trp, along with its 2-fold IAA level, confirmed the relationship of nosR overexpression with Trp in increasing IAA. These results indicate a strong correlation between IAA and NO in A. brasilense SM and suggest the existence of cross-talk or shared signaling mechanisms in these two growth regulators. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  11. In situ biosynthesis of bacterial nanocellulose-CaCO3 hybrid bionanocomposite: One-step process.

    Science.gov (United States)

    Mohammadkazemi, Faranak; Faria, Marisa; Cordeiro, Nereida

    2016-08-01

    In this work, a simple and green route to the synthesis of the bacterial nanocellulose-calcium carbonate (BNC/CaCO3) hybrid bionanocomposites using one-step in situ biosynthesis was studied. The CaCO3 was incorporated in the bacterial nanocellulose structure during the cellulose biosynthesis by Gluconacetobacter xylinus PTCC 1734 bacteria. Hestrin-Schramm (HS) and Zhou (Z) culture media were used to the hybrid bionanocomposites production and the effect of ethanol addition was investigated. Attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, inverse gas chromatography and thermogravimetric analysis were used to characterize the samples. The experimental results demonstrated that the ethanol and culture medium play an important role in the BNC/CaCO3 hybrid bionanocomposites production, structure and properties. The BNC/CaCO3 biosynthesized in Z culture medium revealed higher O/C ratio and amphoteric surface character, which justify the highest CaCO3 content incorporation. The CaCO3 was incorporated into the cellulosic matrix decreasing the bacterial nanocellulose crystallinity. This work reveals the high potential of in situ biosynthesis of BNC/CaCO3 hybrid bionanocomposites and opens a new way to the high value-added applications of bacterial nanocellulose. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Laser-assisted biosynthesis for noble nanoparticles production

    Science.gov (United States)

    Kukhtarev, Tatiana; Edwards, Vernessa; Kukhtareva, Nickolai; Moses, Sherita

    2014-08-01

    Extracellular Biosynthesis technique (EBS) for nanoparticles production has attracted a lot of attention as an environmentally friendly and an inexpensive methodology. Our recent research was focused on the rapid approach of the green synthesis method and the reduction of the homogeneous size distribution of nanoparticles using pulse laser application. Noble nanoparticles (NNPs) were produced using various ethanol and water plant extracts. The plants were chosen based on their biomedical applications. The plants we used were Magnolia grandiflora, Geranium, Aloe `tingtinkie', Aloe barbadensis (Aloe Vera), Eucalyptus angophoroides, Sansevieria trifasciata, Impatiens scapiflora. Water and ethanol extract, were used as reducing agents to produce the nanoparticles. The reaction process was monitored using a UV-Visible spectroscopy. NNPs were characterized by Fourier Transfer Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and the Dynamic Light Scattering technique (DLS). During the pulse laser Nd-YAG illumination (λ=1064nm, 532nm, PE= 450mJ, 200mJ, 10 min) the blue shift of the surface plasmon resonance absorption peak was observed from ~424nm to 403nm for silver NP; and from ~530nm to 520 nm for gold NPs. In addition, NNPs solution after Nd-YAG illumination was characterized by the narrowing of the surface plasmon absorption resonance band, which corresponds to monodispersed NNPS distribution. FTIR, TEM, DLS, Zeta potential results demonstrated that NNPs were surrounded by biological molecules, which naturally stabilized nanosolutions for months. Cytotoxicity investigation of biosynthesized NNPs is in progress.

  13. Cysteine Biosynthesis Controls Serratia marcescens Phospholipase Activity.

    Science.gov (United States)

    Anderson, Mark T; Mitchell, Lindsay A; Mobley, Harry L T

    2017-08-15

    Serratia marcescens causes health care-associated opportunistic infections that can be difficult to treat due to a high incidence of antibiotic resistance. One of the many secreted proteins of S. marcescens is the PhlA phospholipase enzyme. Genes involved in the production and secretion of PhlA were identified by screening a transposon insertion library for phospholipase-deficient mutants on phosphatidylcholine-containing medium. Mutations were identified in four genes ( cyaA , crp , fliJ , and fliP ) that are involved in the flagellum-dependent PhlA secretion pathway. An additional phospholipase-deficient isolate harbored a transposon insertion in the cysE gene encoding a predicted serine O -acetyltransferase required for cysteine biosynthesis. The cysE requirement for extracellular phospholipase activity was confirmed using a fluorogenic phospholipase substrate. Phospholipase activity was restored to the cysE mutant by the addition of exogenous l-cysteine or O -acetylserine to the culture medium and by genetic complementation. Additionally, phlA transcript levels were decreased 6-fold in bacteria lacking cysE and were restored with added cysteine, indicating a role for cysteine-dependent transcriptional regulation of S. marcescens phospholipase activity. S. marcescens cysE mutants also exhibited a defect in swarming motility that was correlated with reduced levels of flhD and fliA flagellar regulator gene transcription. Together, these findings suggest a model in which cysteine is required for the regulation of both extracellular phospholipase activity and surface motility in S. marcescens IMPORTANCE Serratia marcescens is known to secrete multiple extracellular enzymes, but PhlA is unusual in that this protein is thought to be exported by the flagellar transport apparatus. In this study, we demonstrate that both extracellular phospholipase activity and flagellar function are dependent on the cysteine biosynthesis pathway. Furthermore, a disruption of cysteine

  14. In situ biosynthesis of bacterial nanocellulose-CaCO3 hybrid bionanocomposite: One-step process

    International Nuclear Information System (INIS)

    Mohammadkazemi, Faranak; Faria, Marisa; Cordeiro, Nereida

    2016-01-01

    In this work, a simple and green route to the synthesis of the bacterial nanocellulose-calcium carbonate (BNC/CaCO 3 ) hybrid bionanocomposites using one-step in situ biosynthesis was studied. The CaCO 3 was incorporated in the bacterial nanocellulose structure during the cellulose biosynthesis by Gluconacetobacter xylinus PTCC 1734 bacteria. Hestrin-Schramm (HS) and Zhou (Z) culture media were used to the hybrid bionanocomposites production and the effect of ethanol addition was investigated. Attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, inverse gas chromatography and thermogravimetric analysis were used to characterize the samples. The experimental results demonstrated that the ethanol and culture medium play an important role in the BNC/CaCO 3 hybrid bionanocomposites production, structure and properties. The BNC/CaCO 3 biosynthesized in Z culture medium revealed higher O/C ratio and amphoteric surface character, which justify the highest CaCO 3 content incorporation. The CaCO 3 was incorporated into the cellulosic matrix decreasing the bacterial nanocellulose crystallinity. This work reveals the high potential of in situ biosynthesis of BNC/CaCO 3 hybrid bionanocomposites and opens a new way to the high value-added applications of bacterial nanocellulose. - Graphical Abstract: Display Omitted - Highlights: • BNC/CaCO 3 hybrid bionanocomposites were produced using in situ biosynthesis process. • Ethanol and culture medium play an important role in the production and properties. • Z-BNC/CaCO 3 bionanocomposites revealed higher O/C ratio and amphoteric surface character. • CaCO 3 incorporated into the BNC decreased crystallinity.

  15. Merge of terminological resources

    DEFF Research Database (Denmark)

    Henriksen, Lina; Braasch, Anna

    2012-01-01

    – or merging – of terminology resources are strongly needed. This paper discusses prerequisites for successful merging with the focus on identification of candidate duplicates of a subject domain found in the resources to be merged, and it describes automatic merging strategies to be applied to such duplicates...... in electronic terminology resources. Further, some perspectives of manual, supplementary assessment methods supporting the automatic procedures are sketched. Our considerations are primarily based on experience gained in the IATE and EuroTermBank projects, as merging was a much discussed issue in both projects....

  16. Three Principles of Diversity-Generating Biosynthesis.

    Science.gov (United States)

    Gu, Wenjia; Schmidt, Eric W

    2017-10-17

    Natural products are significant therapeutic agents and valuable drug leads. This is likely owing to their three-dimensional structural complexity, which enables them to form complex interactions with biological targets. Enzymes from natural product biosynthetic pathways show great potential to generate natural product-like compounds and libraries. Many challenges still remain in biosynthesis, such as how to rationally synthesize small molecules with novel structures and how to generate maximum chemical diversity. In this Account, we describe recent advances from our laboratory in the synthesis of natural product-like libraries using natural biosynthetic machinery. Our work has focused on the pat and tru biosynthetic pathways to patellamides, trunkamide, and related compounds from cyanobacterial symbionts in marine tunicates. These belong to the cyanobactin class of natural products, which are part of the larger group of ribosomally synthesized and post-translationally modified peptides (RiPPs). These results have enabled the synthesis of rationally designed small molecules and libraries covering more than 1 million estimated derivatives. Because the RiPPs are translated on the ribosome and then enzymatically modified, they are highly compatible with recombinant technologies. This is important because it means that the resulting natural products, their derivatives, and wholly new compounds can be synthesized using the tools of genetic engineering. The RiPPs also represent possibly the most widespread group of bioactive natural products, although this is in part because of the broad definition of what constitutes a RiPP. In addition, the underlying ideas may form the basis for broad-substrate biosynthetic pathways beyond the RiPPs. For example, some of the ideas about kinetic ordering of broad substrate pathways may apply to polyketide or nonribosomal peptide biosynthesis as well. While making these products, we have sought to understand what makes biosynthetic

  17. Polyamine biosynthesis during germination of yeast ascospores.

    Science.gov (United States)

    Brawley, J V; Ferro, A J

    1979-01-01

    The role of the diamine putrescine during germination and outgrowth of ascospores of Saccharomyces cerevisiae was examined. Ornithine decarboxylase activity increased and declined rapidly during germination and outgrowth; peak activity was attained after the cells had proceeded through the G1 interval of the cell cycle, whereas minimal activity was present at the completion of the first cell division. alpha-Methylornithine inhibited both ornithine decarboxylase activity and the in vivo accumulation of putrescine. In the presence of alpha-methylornithireak dormancy and proceed through one cell division. Subsequent cellular growth, however, was retarded but not completely inhibited. The supplementation of Methylglyoxal bis(guanylhydrazone) to sporulation medium greatly inhibited this sexual process. These data suggest that the synthesis of putrescine is not required for the breaking of spore dormancy, but that polyamine biosynthesis may be essential for meiosis and sporulation. PMID:387744

  18. Biosynthesis and function of plant lipids

    International Nuclear Information System (INIS)

    Thomson, W.W.; Mudd, J.B.; Gibbs, M.

    1983-01-01

    The Sixth Annual Symposium in Botany and Plant Physiology was held January 13-15, 1983, at the University of California, Riverside. This volume comprises the papers that were presented. Subjects discussed at the symposium covered a wide range in the field of plant lipids. Biosynthesis of lipids occupied an important fraction of the presentations at the symposium. Subjects included detailed studies of the enzymes of fatty acid synthesis, several discussions of the incorporation of fatty acids into glycerolipids and the further modification of the fatty acids, and the synthesis of glycerolipids and desaturation of fatty acids in both maturing oilseeds and chloroplasts. The physicochemical studies of glycerolipids and sterols in artificial membranes have led to distinct conclusions about their behaviour which must be relevant in the biological membrane. Results on the functional consequences of modifying the galactolipid composition in the chloroplast were an encouraging sign of progress in the attempts to relate membrane lipid composition to physiological function

  19. Biosurfactant Mediated Biosynthesis of Selected Metallic Nanoparticles

    Science.gov (United States)

    Płaza, Grażyna A.; Chojniak, Joanna; Banat, Ibrahim M.

    2014-01-01

    Developing a reliable experimental protocol for the synthesis of nanomaterials is one of the challenging topics in current nanotechnology particularly in the context of the recent drive to promote green technologies in their synthesis. The increasing need to develop clean, nontoxic and environmentally safe production processes for nanoparticles to reduce environmental impact, minimize waste and increase energy efficiency has become essential in this field. Consequently, recent studies on the use of microorganisms in the synthesis of selected nanoparticles are gaining increased interest as they represent an exciting area of research with considerable development potential. Microorganisms are known to be capable of synthesizing inorganic molecules that are deposited either intra- or extracellularly. This review presents a brief overview of current research on the use of biosurfactants in the biosynthesis of selected metallic nanoparticles and their potential importance. PMID:25110864

  20. Terpenoids and Their Biosynthesis in Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Bagmi Pattanaik

    2015-01-01

    Full Text Available Terpenoids, or isoprenoids, are a family of compounds with great structural diversity which are essential for all living organisms. In cyanobacteria, they are synthesized from the methylerythritol-phosphate (MEP pathway, using glyceraldehyde 3-phosphate and pyruvate produced by photosynthesis as substrates. The products of the MEP pathway are the isomeric five-carbon compounds isopentenyl diphosphate and dimethylallyl diphosphate, which in turn form the basic building blocks for formation of all terpenoids. Many terpenoid compounds have useful properties and are of interest in the fields of pharmaceuticals and nutrition, and even potentially as future biofuels. The MEP pathway, its function and regulation, and the subsequent formation of terpenoids have not been fully elucidated in cyanobacteria, despite its relevance for biotechnological applications. In this review, we summarize the present knowledge about cyanobacterial terpenoid biosynthesis, both regarding the native metabolism and regarding metabolic engineering of cyanobacteria for heterologous production of non-native terpenoids.

  1. Terpenoids and Their Biosynthesis in Cyanobacteria

    Science.gov (United States)

    Pattanaik, Bagmi; Lindberg, Pia

    2015-01-01

    Terpenoids, or isoprenoids, are a family of compounds with great structural diversity which are essential for all living organisms. In cyanobacteria, they are synthesized from the methylerythritol-phosphate (MEP) pathway, using glyceraldehyde 3-phosphate and pyruvate produced by photosynthesis as substrates. The products of the MEP pathway are the isomeric five-carbon compounds isopentenyl diphosphate and dimethylallyl diphosphate, which in turn form the basic building blocks for formation of all terpenoids. Many terpenoid compounds have useful properties and are of interest in the fields of pharmaceuticals and nutrition, and even potentially as future biofuels. The MEP pathway, its function and regulation, and the subsequent formation of terpenoids have not been fully elucidated in cyanobacteria, despite its relevance for biotechnological applications. In this review, we summarize the present knowledge about cyanobacterial terpenoid biosynthesis, both regarding the native metabolism and regarding metabolic engineering of cyanobacteria for heterologous production of non-native terpenoids. PMID:25615610

  2. A Molecular Description of Cellulose Biosynthesis

    Science.gov (United States)

    McNamara, Joshua T.; Morgan, Jacob L.W.; Zimmer, Jochen

    2016-01-01

    Cellulose is the most abundant biopolymer on Earth, and certain organisms from bacteria to plants and animals synthesize cellulose as an extracellular polymer for various biological functions. Humans have used cellulose for millennia as a material and an energy source, and the advent of a lignocellulosic fuel industry will elevate it to the primary carbon source for the burgeoning renewable energy sector. Despite the biological and societal importance of cellulose, the molecular mechanism by which it is synthesized is now only beginning to emerge. On the basis of recent advances in structural and molecular biology on bacterial cellulose synthases, we review emerging concepts of how the enzymes polymerize glucose molecules, how the nascent polymer is transported across the plasma membrane, and how bacterial cellulose biosynthesis is regulated during biofilm formation. Additionally, we review evolutionary commonalities and differences between cellulose synthases that modulate the nature of the cellulose product formed. PMID:26034894

  3. Biosurfactant Mediated Biosynthesis of Selected Metallic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Grażyna A. Płaza

    2014-08-01

    Full Text Available Developing a reliable experimental protocol for the synthesis of nanomaterials is one of the challenging topics in current nanotechnology particularly in the context of the recent drive to promote green technologies in their synthesis. The increasing need to develop clean, nontoxic and environmentally safe production processes for nanoparticles to reduce environmental impact, minimize waste and increase energy efficiency has become essential in this field. Consequently, recent studies on the use of microorganisms in the synthesis of selected nanoparticles are gaining increased interest as they represent an exciting area of research with considerable development potential. Microorganisms are known to be capable of synthesizing inorganic molecules that are deposited either intra- or extracellularly. This review presents a brief overview of current research on the use of biosurfactants in the biosynthesis of selected metallic nanoparticles and their potential importance.

  4. Sterol Biosynthesis Pathway as Target for Anti-trypanosomatid Drugs

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    2009-01-01

    Full Text Available Sterols are constituents of the cellular membranes that are essential for their normal structure and function. In mammalian cells, cholesterol is the main sterol found in the various membranes. However, other sterols predominate in eukaryotic microorganisms such as fungi and protozoa. It is now well established that an important metabolic pathway in fungi and in members of the Trypanosomatidae family is one that produces a special class of sterols, including ergosterol, and other 24-methyl sterols, which are required for parasitic growth and viability, but are absent from mammalian host cells. Currently, there are several drugs that interfere with sterol biosynthesis (SB that are in use to treat diseases such as high cholesterol in humans and fungal infections. In this review, we analyze the effects of drugs such as (a statins, which act on the mevalonate pathway by inhibiting HMG-CoA reductase, (b bisphosphonates, which interfere with the isoprenoid pathway in the step catalyzed by farnesyl diphosphate synthase, (c zaragozic acids and quinuclidines, inhibitors of squalene synthase (SQS, which catalyzes the first committed step in sterol biosynthesis, (d allylamines, inhibitors of squalene epoxidase, (e azoles, which inhibit C14α-demethylase, and (f azasterols, which inhibit Δ24(25-sterol methyltransferase (SMT. Inhibition of this last step appears to have high selectivity for fungi and trypanosomatids, since this enzyme is not found in mammalian cells. We review here the IC50 values of these various inhibitors, their effects on the growth of trypanosomatids (both in axenic cultures and in cell cultures, and their effects on protozoan structural organization (as evaluted by light and electron microscopy and lipid composition. The results show that the mitochondrial membrane as well as the membrane lining the protozoan cell body and flagellum are the main targets. Probably as a consequence of these primary effects, other important changes take

  5. Merge of terminological resources

    DEFF Research Database (Denmark)

    Henriksen, Lina; Braasch, Anna

    2012-01-01

    In our globalized world, the amount of cross-national communication increases rapidly, which also calls for easy access to multi-lingual high quality terminological resources. Sharing of terminology resources is currently becoming common practice, and efficient strategies for integration...... – or merging – of terminology resources are strongly needed. This paper discusses prerequisites for successful merging with the focus on identification of candidate duplicates of a subject domain found in the resources to be merged, and it describes automatic merging strategies to be applied to such duplicates...... in electronic terminology resources. Further, some perspectives of manual, supplementary assessment methods supporting the automatic procedures are sketched. Our considerations are primarily based on experience gained in the IATE and EuroTermBank projects, as merging was a much discussed issue in both projects....

  6. Renewable energy resources

    DEFF Research Database (Denmark)

    Ellabban, Omar S.; Abu-Rub, Haitham A.; Blaabjerg, Frede

    2014-01-01

    Electric energy security is essential, yet the high cost and limited sources of fossil fuels, in addition to the need to reduce greenhouse gasses emission, have made renewable resources attractive in world energy-based economies. The potential for renewable energy resources is enormous because...... they can, in principle, exponentially exceed the world's energy demand; therefore, these types of resources will have a significant share in the future global energy portfolio, much of which is now concentrating on advancing their pool of renewable energy resources. Accordingly, this paper presents how...... renewable energy resources are currently being used, scientific developments to improve their use, their future prospects, and their deployment. Additionally, the paper represents the impact of power electronics and smart grid technologies that can enable the proportionate share of renewable energy...

  7. Acylphloroglucinol Biosynthesis in Strawberry Fruit1

    Science.gov (United States)

    Song, Chuankui; Ring, Ludwig; Hoffmann, Thomas; Huang, Fong-Chin; Slovin, Janet; Schwab, Wilfried

    2015-01-01

    Phenolics have health-promoting properties and are a major group of metabolites in fruit crops. Through reverse genetic analysis of the functions of four ripening-related genes in the octoploid strawberry (Fragaria × ananassa), we discovered four acylphloroglucinol (APG)-glucosides as native Fragaria spp. fruit metabolites whose levels were differently regulated in the transgenic fruits. The biosynthesis of the APG aglycones was investigated by examination of the enzymatic properties of three recombinant Fragaria vesca chalcone synthase (FvCHS) proteins. CHS is involved in anthocyanin biosynthesis during ripening. The F. vesca enzymes readily catalyzed the condensation of two intermediates in branched-chain amino acid metabolism, isovaleryl-Coenzyme A (CoA) and isobutyryl-CoA, with three molecules of malonyl-CoA to form phlorisovalerophenone and phlorisobutyrophenone, respectively, and formed naringenin chalcone when 4-coumaroyl-CoA was used as starter molecule. Isovaleryl-CoA was the preferred starter substrate of FvCHS2-1. Suppression of CHS activity in both transient and stable CHS-silenced fruit resulted in a substantial decrease of APG glucosides and anthocyanins and enhanced levels of volatiles derived from branched-chain amino acids. The proposed APG pathway was confirmed by feeding isotopically labeled amino acids. Thus, Fragaria spp. plants have the capacity to synthesize pharmaceutically important APGs using dual functional CHS/(phloriso)valerophenone synthases that are expressed during fruit ripening. Duplication and adaptive evolution of CHS is the most probable scenario and might be generally applicable to other plants. The results highlight that important promiscuous gene function may be missed when annotation relies solely on in silico analysis. PMID:26169681

  8. Biosynthesis of Anisotropic Silver Nanoparticles by Bhargavaea indica and Their Synergistic Effect with Antibiotics against Pathogenic Microorganisms

    OpenAIRE

    Singh, Priyanka; Kim, Yeon Ju; Singh, Hina; Mathiyalagan, Ramya; Wang, Chao; Yang, Deok Chun

    2015-01-01

    The strain Bhargavaea indica DC1 isolated from four-year-old P. ginseng rhizospheric soil was used to perform rapid and extracellular biosynthesis of anisotropic silver nanoparticles. The ultraviolet-visible (UV-vis) spectra of the reaction mixture containing silver nanoparticles showed a peak at 460 nm, corresponding to the surface plasmon absorbance of silver nanoparticles. Field-emission transmission electron microscopy (FE-TEM) structural characterization revealed the nanobar, pentagon, s...

  9. Tapping the unexploited plant resources for the synthesis of silver ...

    African Journals Online (AJOL)

    Tapping the unexploited plant resources for the synthesis of silver nanoparticles. ... H. annus was found to exhibit strong potential for rapid reduction of silver ions. It was observed that there is no ... synthesised. The work adds to the confirmation of previous reports on biosynthesis of nanometals using plant leaf extracts.

  10. Electronics and electronic systems

    CERN Document Server

    Olsen, George H

    1987-01-01

    Electronics and Electronic Systems explores the significant developments in the field of electronics and electronic devices. This book is organized into three parts encompassing 11 chapters that discuss the fundamental circuit theory and the principles of analog and digital electronics. This book deals first with the passive components of electronic systems, such as resistors, capacitors, and inductors. These topics are followed by a discussion on the analysis of electronic circuits, which involves three ways, namely, the actual circuit, graphical techniques, and rule of thumb. The remaining p

  11. Engineering E. coli for caffeic acid biosynthesis from renewable sugars.

    Science.gov (United States)

    Zhang, Haoran; Stephanopoulos, Gregory

    2013-04-01

    Caffeic acid is a valuable aromatic compound that possesses many important pharmacological activities. In structure, caffeic acid belongs to the hydroxycinnamic acid family and can be biosynthesized from the aromatic amino acid tyrosine. In the present paper, the caffeic acid biosynthesis pathway was reconstituted in engineered Escherichia coli to produce caffeic acid from simple biomass sugar glucose and xylose. Different engineering approaches were utilized to optimize the production. Specifically, two parallel biosynthesis routes leading from tyrosine to caffeic acid were studied. The copy number of the intermediate biosynthesis genes was varied to find appropriate gene doses for caffeic acid biosynthesis. Three different media, including a MOPS medium, a synthetic medium, and a rich medium, were also examined to improve the production. The highest specific caffeic acid production achieved was 38 mg/L/OD. Lastly, cultivation of engineered E. coli in a bioreactor resulted in a production of 106 mg/L caffeic acid after 4 days.

  12. Stimulation of artemisinin biosynthesis in Artemisia annua hairy ...

    African Journals Online (AJOL)

    , the OGA-induced reactive oxygen species (ROS) were involved in stimulating the artemisinin biosynthesis in the hairy roots. This is the first report on the stimulation of artemisinin production in hairy roots by an oligogalacturonide elicitor.

  13. Biosynthesis, regulation and biological role of strigolactones in rice

    NARCIS (Netherlands)

    Moura Luis Cardoso, De C.S.

    2014-01-01

    In her thesis Catarina Cardoso studied strigolactone biosynthesis in rice. Strigolactones are multifunctional compounds produced by plants. They are plant hormones that regulate plant architecture, but in addition plants release strigolactones into the soil to communicate and initiate beneficial

  14. NAD+ biosynthesis, aging, and disease [version 1; referees: 2 approved

    OpenAIRE

    Sean Johnson; Shin–ichiro Imai

    2018-01-01

    Nicotinamide adenine dinucleotide (NAD+) biosynthesis and its regulation have recently been attracting markedly increasing interest. Aging is marked by a systemic decrease in NAD+ across multiple tissues. The dysfunction of NAD+ biosynthesis plays a critical role in the pathophysiologies of multiple diseases, including age-associated metabolic disorders, neurodegenerative diseases, and mental disorders. As downstream effectors, NAD+-dependent enzymes, such as sirtuins, are involved in the pro...

  15. The Distant Siblings—A Phylogenomic Roadmap Illuminates the Origins of Extant Diversity in Fungal Aromatic Polyketide Biosynthesis

    Science.gov (United States)

    Koczyk, Grzegorz; Dawidziuk, Adam; Popiel, Delfina

    2015-01-01

    Abstract In recent years, the influx of newly sequenced fungal genomes has enabled sampling of secondary metabolite biosynthesis on an unprecedented scale. However, explanations of extant diversity which take into account both large-scale phylogeny reconstructions and knowledge gained from multiple genome projects are still lacking. We analyzed the evolutionary sources of genetic diversity in aromatic polyketide biosynthesis in over 100 model fungal genomes. By reconciling the history of over 400 nonreducing polyketide synthases (NR-PKSs) with corresponding species history, we demonstrate that extant fungal NR-PKSs are clades of distant siblings, originating from a burst of duplications in early Pezizomycotina and thinned by extensive losses. The capability of higher fungi to biosynthesize the simplest precursor molecule (orsellinic acid) is highlighted as an ancestral trait underlying biosynthesis of aromatic compounds. This base activity was modified during early evolution of filamentous fungi, toward divergent reaction schemes associated with biosynthesis of, for example, aflatoxins and fusarubins (C4–C9 cyclization) or various anthraquinone derivatives (C6–C11 cyclization). The functional plasticity is further shown to have been supplemented by modularization of domain architecture into discrete pieces (conserved splice junctions within product template domain), as well as tight linkage of key accessory enzyme families and divergence in employed transcriptional factors. Although the majority of discord between species and gene history is explained by ancient duplications, this landscape has been altered by more recent duplications, as well as multiple horizontal gene transfers. The 25 detected transfers include previously undescribed events leading to emergence of, for example, fusarubin biosynthesis in Fusarium genus. Both the underlying data and the results of present analysis (including alternative scenarios revealed by sampling multiple reconciliation

  16. Fenarimol, a Pyrimidine-Type Fungicide, Inhibits Brassinosteroid Biosynthesis

    Directory of Open Access Journals (Sweden)

    Keimei Oh

    2015-07-01

    Full Text Available The plant steroid hormone brassinosteroids (BRs are important signal mediators that regulate broad aspects of plant growth and development. With the discovery of brassinoazole (Brz, the first specific inhibitor of BR biosynthesis, several triazole-type BR biosynthesis inhibitors have been developed. In this article, we report that fenarimol (FM, a pyrimidine-type fungicide, exhibits potent inhibitory activity against BR biosynthesis. FM induces dwarfism and the open cotyledon phenotype of Arabidopsis seedlings in the dark. The IC50 value for FM to inhibit stem elongation of Arabidopsis seedlings grown in the dark was approximately 1.8 ± 0.2 μM. FM-induced dwarfism of Arabidopsis seedlings could be restored by brassinolide (BL but not by gibberellin (GA. Assessment of the target site of FM in BR biosynthesis by feeding BR biosynthesis intermediates indicated that FM interferes with the side chain hydroxylation of BR biosynthesis from campestanol to teasterone. Determination of the binding affinity of FM to purified recombinant CYP90D1 indicated that FM induced a typical type II binding spectrum with a Kd value of approximately 0.79 μM. Quantitative real-time PCR analysis of the expression level of the BR responsive gene in Arabidopsis seedlings indicated that FM induces the BR deficiency in Arabidopsis.

  17. Complete Biosynthesis of Anthocyanins Using E. coli Polycultures.

    Science.gov (United States)

    Jones, J Andrew; Vernacchio, Victoria R; Collins, Shannon M; Shirke, Abhijit N; Xiu, Yu; Englaender, Jacob A; Cress, Brady F; McCutcheon, Catherine C; Linhardt, Robert J; Gross, Richard A; Koffas, Mattheos A G

    2017-06-06

    Fermentation-based chemical production strategies provide a feasible route for the rapid, safe, and sustainable production of a wide variety of important chemical products, ranging from fuels to pharmaceuticals. These strategies have yet to find wide industrial utilization due to their inability to economically compete with traditional extraction and chemical production methods. Here, we engineer for the first time the complex microbial biosynthesis of an anthocyanin plant natural product, starting from sugar. This was accomplished through the development of a synthetic, 4-strain Escherichia coli polyculture collectively expressing 15 exogenous or modified pathway enzymes from diverse plants and other microbes. This synthetic consortium-based approach enables the functional expression and connection of lengthy pathways while effectively managing the accompanying metabolic burden. The de novo production of specific anthocyanin molecules, such as calistephin, has been an elusive metabolic engineering target for over a decade. The utilization of our polyculture strategy affords milligram-per-liter production titers. This study also lays the groundwork for significant advances in strain and process design toward the development of cost-competitive biochemical production hosts through nontraditional methodologies. IMPORTANCE To efficiently express active extensive recombinant pathways with high flux in microbial hosts requires careful balance and allocation of metabolic resources such as ATP, reducing equivalents, and malonyl coenzyme A (malonyl-CoA), as well as various other pathway-dependent cofactors and precursors. To address this issue, we report the design, characterization, and implementation of the first synthetic 4-strain polyculture. Division of the overexpression of 15 enzymes and transcription factors over 4 independent strain modules allowed for the division of metabolic burden and for independent strain optimization for module-specific metabolite needs

  18. Alternative oxidase impacts ganoderic acid biosynthesis by regulating intracellular ROS levels in Ganoderma lucidum.

    Science.gov (United States)

    Shi, Deng-Ke; Zhu, Jing; Sun, Ze-Hua; Zhang, Guang; Liu, Rui; Zhang, Tian-Jun; Wang, Sheng-Li; Ren, Ang; Zhao, Ming-Wen

    2017-10-01

    The alternative oxidase (AOX), which forms a branch of the mitochondrial respiratory electron transport pathway, functions to sustain electron flux and alleviate reactive oxygen species (ROS) production. In this article, a homologous AOX gene was identified in Ganoderma lucidum. The coding sequence of the AOX gene in G. lucidum contains 1038 nucleotides and encodes a protein of 39.48 kDa. RNA interference (RNAi) was used to study the function of AOX in G. lucidum, and two silenced strains (AOXi6 and AOXi21) were obtained, showing significant decreases of approximately 60 and 50 %, respectively, in alternative pathway respiratory efficiency compared to WT. The content of ganoderic acid (GA) in the mutant strains AOXi6 and AOXi21 showed significant increases of approximately 42 and 44 %, respectively, compared to WT. Elevated contents of intermediate metabolites in GA biosynthesis and elevated transcription levels of corresponding genes were also observed in the mutant strains AOXi6 and AOXi21. In addition, the intracellular ROS content in strains AOXi6 and AOXi21 was significantly increased, by approximately 1.75- and 1.93-fold, respectively, compared with WT. Furthermore, adding N-acetyl-l-cysteine (NAC), a ROS scavenger, significantly depressed the intracellular ROS content and GA accumulation in AOX-silenced strains. These results indicate that AOX affects GA biosynthesis by regulating intracellular ROS levels. Our research revealed the important role of AOX in the secondary metabolism of G. lucidum.

  19. Genomic analysis of the human gut microbiome suggests novel enzymes involved in quinone biosynthesis

    Directory of Open Access Journals (Sweden)

    Dmitry A Ravcheev

    2016-02-01

    Full Text Available Ubiquinone and menaquinone are membrane lipid-soluble carriers of electrons that are essential for cellular respiration. Eukaryotic cells can synthesize ubiquinone but not menaquinone, whereas prokaryotes can synthesize both quinones. So far, most of the human gut microbiome (HGM studies have been based on metagenomic analysis. Here, we applied an analysis of individual HGM genomes to the identification of ubiquinone and menaquinone biosynthetic pathways. In our opinion, the shift from metagenomics to analysis of individual genomes is a pivotal milestone in investigation of bacterial communities, including the HGM. The key results of this study are as follows. (i The distribution of the canonical pathways in the HGM genomes was consistent with previous reports and with the distribution of the quinone-dependent reductases for electron acceptors. (ii The comparative genomics analysis identified four alternative forms of the previously known enzymes for quinone biosynthesis. (iii Genes for the previously unknown part of the futalosine pathway were identified, and the corresponding biochemical reactions were proposed. We discuss the remaining gaps in the menaquinone and ubiquinone pathways in some of the microbes, which indicate the existence of further alternate genes or routes. Together, these findings provide further insight into the biosynthesis of quinones in bacteria and the physiology of the HGM.

  20. Preliminary studies of the biosynthesis of Austin

    International Nuclear Information System (INIS)

    Wicnienski, N.A.

    1979-01-01

    Aspergillus ustus is one of the most prevalent fungi in the soil. There are now two reports of the occurrence of toxin-producing strains of this fungus on stored foodstuffs. In addition, strains of A. ustus have been isolated along with Penicillium species from samples of South African cheeses. All A. ustus isolates tested were judged to be highly toxic to ducklings when grown on maize meal, however, the toxins involved were not isolated. Austin is the trivial name of one of the toxins made by the fungus found on stored food. Preliminary work to studying the biosynthesis of this compound using 13 C-labeled sodium acetate is reported here. The feasibility of the biosynthetic study was determined by feeding [1- 14 C]-sodium acetate to A. ustus cultures. The assignments made in the 13 C-nmr spectrum of Austin are shown. The lowest dilution factor obtained in [1- 14 C]-sodium acetate feeding experiments was 14. This dilution factor is sufficiently low to allow a successful feeding of [1,2- 13 C 2 ]-sodium acetate. A new metabolite of A. ustus, deacetylaustin, was isolated and identified. An alkaloid of unknown structure was also isolated from the fungus

  1. Biosynthesis of secondary metabolites in sugarcane

    Directory of Open Access Journals (Sweden)

    S.C. França

    2001-12-01

    Full Text Available A set of genes related to secondary metabolism was extracted from the sugarcane expressed sequence tag (SUCEST database and was used to investigate both the gene expression pattern of key enzymes regulating the main biosynthetic secondary metabolism pathways and the major classes of metabolites involved in the response of sugarcane to environmental and developmental cues. The SUCEST database was constructed with tissues in different physiological conditions which had been collected under varied situation of environmental stress. This database allows researchers to identify and characterize the expressed genes of a wide range of putative enzymes able to catalyze steps in the phenylpropanoid, isoprenoid and other pathways of the special metabolic mechanisms involved in the response of sugarcane to environmental changes. Our results show that sugarcane cDNAs encoded putative ultra-violet induced sesquiterpene cyclases (SC; chalcone synthase (CHS, the first enzyme in the pathway branch for flavonoid biosynthesis; isoflavone synthase (IFS, involved in plant defense and root nodulation; isoflavone reductase (IFR, a key enzyme in phenylpropanoid phytoalexin biosynthesis; and caffeic acid-O-methyltransferase, a key enzyme in the biosynthesis of lignin cell wall precursors. High levels of CHS transcripts from plantlets infected with Herbaspirillum rubri or Gluconacetobacter diazotroficans suggests that agents of biotic stress can elicit flavonoid biosynthesis in sugarcane. From this data we have predicted the profile of isoprenoid and phenylpropanoid metabolism in sugarcane and pointed the branches of secondary metabolism activated during tissue-specific stages of development and the adaptive response of sugarcane to agents of biotic and abiotic stress, although our assignment of enzyme function should be confirmed by careful biochemical and genetic supporting evidence.Este trabalho foi realizado com os objetivos de gerar uma coleção de genes

  2. Engineering bacteria for enhanced polyhydroxyalkanoates (PHA biosynthesis

    Directory of Open Access Journals (Sweden)

    Guo-Qiang Chen

    2017-09-01

    Full Text Available Polyhydroxyalkanoates (PHA have been produced by some bacteria as bioplastics for many years. Yet their commercialization is still on the way. A few issues are related to the difficulty of PHA commercialization: namely, high cost and instabilities on molecular weights (Mw and structures, thus instability on thermo-mechanical properties. The high cost is the result of complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and slow growth of microorganisms as well as difficulty of downstream separation. Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles, developments of engineering approaches for the extremophiles, increase on carbon substrates to PHA conversion and controlling Mw of PHA. The concept proof studies could still be conducted on E. coli or Pseudomonas spp. that are easily used for molecular manipulations. In this review, we will use E. coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.

  3. Engineering bacteria for enhanced polyhydroxyalkanoates (PHA) biosynthesis.

    Science.gov (United States)

    Chen, Guo-Qiang; Jiang, Xiao-Ran

    2017-09-01

    Polyhydroxyalkanoates (PHA) have been produced by some bacteria as bioplastics for many years. Yet their commercialization is still on the way. A few issues are related to the difficulty of PHA commercialization: namely, high cost and instabilities on molecular weights (Mw) and structures, thus instability on thermo-mechanical properties. The high cost is the result of complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and slow growth of microorganisms as well as difficulty of downstream separation. Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles, developments of engineering approaches for the extremophiles, increase on carbon substrates to PHA conversion and controlling Mw of PHA. The concept proof studies could still be conducted on E. coli or Pseudomonas spp. that are easily used for molecular manipulations. In this review, we will use E. coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.

  4. Biosynthesis of myristic acid in luminescent bacteria

    International Nuclear Information System (INIS)

    Byers, D.M.

    1987-01-01

    In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with [ 14 C] acetate in a nutrient-depleted medium accumulated substantial tree [ 14 C]fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with [ 14 C]acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition

  5. Control of triacylglycerol biosynthesis in plants

    Energy Technology Data Exchange (ETDEWEB)

    1993-01-31

    Seeds of most species of the Umbelliferae (Apiaciae), Araliaceae, and Garryaceae families are characterized by their high content of the unusual C[sub 18] monounsaturated fatty acid petroselinic acid (18:l[Delta][sup 6cis]). Prior to a recent report of this lab, little was known of the biosynthetic origin of the cis[Delta][sup 6] double bond of petroselinic acid. Such knowledge may be of both biochemical and biotechnological significance. Because petroselinic acid is potentially the product of a novel desaturase, information regarding its synthesis may contribute to an understanding of fatty acid desaturation mechanisms in plants. Through chemical cleavage at its double bond, petroselinic acid can be used as a precursor of lauric acid (12:0), a component of detergents and surfactants, and adipic acid (6:0 dicarboxylic), the monomeric component of nylon 6,6. Therefore, the development of an agronomic source of an oil rich in petroselinic acid is of biotechnological interest. As such, studies of petroselinic acid biosynthesis may provide basic information required for any attempt to genetically engineer the production and accumulation of this fatty acid in an existing oilseed.

  6. A Biotin Biosynthesis Gene Restricted to Helicobacter

    Science.gov (United States)

    Bi, Hongkai; Zhu, Lei; Jia, Jia; Cronan, John E.

    2016-01-01

    In most bacteria the last step in synthesis of the pimelate moiety of biotin is cleavage of the ester bond of pimeloyl-acyl carrier protein (ACP) methyl ester. The paradigm cleavage enzyme is Escherichia coli BioH which together with the BioC methyltransferase allows synthesis of the pimelate moiety by a modified fatty acid biosynthetic pathway. Analyses of the extant bacterial genomes showed that bioH is absent from many bioC-containing bacteria and is replaced by other genes. Helicobacter pylori lacks a gene encoding a homologue of the known pimeloyl-ACP methyl ester cleavage enzymes suggesting that it encodes a novel enzyme that cleaves this intermediate. We isolated the H. pylori gene encoding this enzyme, bioV, by complementation of an E. coli bioH deletion strain. Purified BioV cleaved the physiological substrate, pimeloyl-ACP methyl ester to pimeloyl-ACP by use of a catalytic triad, each member of which was essential for activity. The role of BioV in biotin biosynthesis was demonstrated using a reconstituted in vitro desthiobiotin synthesis system. BioV homologues seem the sole pimeloyl-ACP methyl ester esterase present in the Helicobacter species and their occurrence only in H. pylori and close relatives provide a target for development of drugs to specifically treat Helicobacter infections. PMID:26868423

  7. Estrogen biosynthesis in human uterine adenomyosis

    International Nuclear Information System (INIS)

    Urabe, Mamoru; Yamamoto, Takara; Kitawaki, Jo; Honjo, Hideo; Okada, Hiroji

    1989-01-01

    Estrogen biosynthesis (aromatiase activity) was investigated in human adenomyosis tissue and compared with that of the normal myometrium, endometrium, and endometrical cancer tissues. Homogenates were incubated with [1,2,6,7- 3 H]androstenedione and NADPH at 37 deg. C for 1 h. After stopping the enzymatic reaction with ethyl acetate, [4- 14 C]estrone and [4- 14 C]estradiol-17β were added to the incubated sample. Estrone and estradiol were purified and identified by Bio-Rad AG1-X2 column chromatography, thin-layer chromatography and co-crystallization. Estrogen formed in the incubated sample was calculated from the 3 H/ 14 C ratio of the final crystal. The value for estrone formed from androstenedione was 52-132 fmol . h -1. g -1 wet weight. Aromatase activity in the adenomyosis tissues was higher than that in normal endometrial or myometrial tissues, but lower than that found in myometrial or endometrial tumour tissue. Furthermore, we investigated the effect of danazol, progresterone, and medroxyprogesterone acetate on adenomyosis cells in primary cultures. Aromatase activity in adenomyosis was blocked by danazol, but stimulated by progesterone and MPA. These results indicate that aromatase activity in adenomyosis may contribute to the growth of the ectopic endometrial tissue which occurs in this disease. (author)

  8. Glycoprotein biosynthesis by human normal platelets

    International Nuclear Information System (INIS)

    Rodriguez, P.; Bello, O.; Apitz-Castro, R.

    1987-01-01

    Incorporation of radioactive Man, Gal, Fuc, Glc-N, and NANA into washed human normal platelets and endogenous glycoproteins has been found. Both parameters were time dependent. Analysis of hydrolyzed labeled glycoproteins by paper chromatography revealed that the radioactive monosaccharide incubated with the platelets had not been converted into other sugars. Acid hydrolysis demonstrates the presence of a glycosidic linkage. All the effort directed to the demonstration of the existence of a lipid-sugar intermediate in intact human platelets yielded negative results for Man and Glc-N used as precursors. The incorporation of these sugars into glycoproteins is insensitive to bacitracin, suggesting no involvement of lipid-linked saccharides in the synthesis of glycoproteins in human blood platelets. The absence of inhibition of the glycosylation process in the presence of cycloheximide suggests that the sugars are added to proteins present in the intact platelets. These results support the contention that glycoprotein biosynthesis in human blood platelets observed under our experimental conditions is effected through direct sugar nucleotide glycosylation

  9. Biosynthesis and metabolism of steroids in molluscs.

    Science.gov (United States)

    Fernandes, Denise; Loi, Barbara; Porte, Cinta

    2011-11-01

    Molluscs are the second most diverse animal group, they are ecologically important and they are considered excellent indicators of ecosystem health. Some species have been widely used in pollution biomonitoring programs; however, their endocrinology is still poorly known. Despite some studies reporting the presence of (vertebrate-type) steroids in molluscs, information regarding enzymatic pathways involved in steroid synthesis and further catabolism of those steroids is still fragmentary. Regarding steroidogenesis, a number of excellent studies were performed in the 70s using different radio-labelled steroid precursors and detecting the formation of different metabolites. But, since then a long gap of research exist until the late 90s when the 'endocrine disruption' issue raised the need of a better knowledge of mollusc (and invertebrate) endocrinology in order to assess alterations caused by pollutants. Here we summarize past and recent studies dealing with steroid biosynthesis and metabolism in different mollusc species. Most of these studies suggest the involvement of steroids in mollusc reproduction. However, the knowledge is still fragmentary and many questions remain to be answered. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Transcriptional analysis of apple fruit proanthocyanidin biosynthesis

    Science.gov (United States)

    Henry-Kirk, Rebecca A.

    2012-01-01

    Proanthocyanidins (PAs) are products of the flavonoid pathway, which also leads to the production of anthocyanins and flavonols. Many flavonoids have antioxidant properties and may have beneficial effects for human health. PAs are found in the seeds and fruits of many plants. In apple fruit (Malus × domestica Borkh.), the flavonoid biosynthetic pathway is most active in the skin, with the flavan-3-ols, catechin, and epicatechin acting as the initiating units for the synthesis of PA polymers. This study examined the genes involved in the production of PAs in three apple cultivars: two heritage apple cultivars, Hetlina and Devonshire Quarrenden, and a commercial cultivar, Royal Gala. HPLC analysis shows that tree-ripe fruit from Hetlina and Devonshire Quarrenden had a higher phenolic content than Royal Gala. Epicatechin and catechin biosynthesis is under the control of the biosynthetic enzymes anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR1), respectively. Counter-intuitively, real-time quantitative PCR analysis showed that the expression levels of Royal Gala LAR1 and ANR were significantly higher than those of both Devonshire Quarrenden and Hetlina. This suggests that a compensatory feedback mechanism may be active, whereby low concentrations of PAs may induce higher expression of gene transcripts. Further investigation is required into the regulation of these key enzymes in apple. Abbreviations:ANOVAanalysis of varianceANRanthocyanidin reductaseDADdiode array detectorDAFBdays after full bloomDFRdihydroflavonol reductaseLARleucoanthocyanidin reductaseLC-MSliquid chromatography/mass spectrometryPAproanthocyanidinqPCRreal-time quantitative PCR PMID:22859681

  11. Explorations into the biosynthesis of bioscorine

    Energy Technology Data Exchange (ETDEWEB)

    Michelson, R.H.

    1988-01-01

    The biosynthesis of dioscorine in Dioscorea hispida has been studied by the feeding of putative precursors labelled at specific positions with {sup 2}H, {sup 3}H, and {sup 14}C. Administration of (3-{sup 14}C)3-hydroxy-3-methylglutaric acid to D. hispida by the wick method afforded dioscorine labelled preferentially at the C{sub 10} position implying that the biosynthetic pathway to the acetate-derived half of the dioscorine skeleton is going through this compound. Administration of ethyl (6-{sup 14}C)orsellinate to D. hispida by the wick method failed to give an appreciable incorporation into dioscroine thereby disproving an alternative mechanism describing the formation of the acetate-derived half of the dioscorine skeleton. Two attempts to simulate the alternative mechanism by oxidatively cleaving ethyl orsellinate also failed, further disfavoring this mechanism. Administration of (2,3){sup 13}C{sub 2}, {sup 14}C{sub 2}succinic acid, (3-{sup 14}C)aspartic acid and (7a-{sup 14}C)tryptophan by the leaf painting method gave very low incorporations into dioscorine making determination of the source of the nicotinic acid half of the dioscorine skeleton inconclusive. Administration of (6-{sup 2}H, {sup 3}H)nicotinic acid to D. hispida by the wick method afforded dioscorine exhibiting complete retention of {sup 3}H thereby disfavoring a mechanism involving a 3,6-dihydropyridine intermediate in the formation of the dioscorine skeleton.

  12. Water Resources

    International Nuclear Information System (INIS)

    Abira, M.A.

    1997-01-01

    Water is essential for life and ecological sustenance; its availability is essential component of national welfare and productivity.The country's socio-economic activities are largely dependent on the natural endowment of water resources. Kenya's water resources comprises of surface waters (rivers, lakes and wetlands) and ground water. Surface water forms 86% of total water resources while the rest is ground water Geological, topographical and climatic factors influence the natural availability and distribution of water with the rainfall distribution having the major influence. Water resources in Kenya are continuously under threat of depletion and quality degradation owing to rising population, industrialization, changing land use and settlement activities as well as natural changes. However, the anticipated climate change is likely to exacerbate the situation resulting in increased conflict over water use rights in particular, and, natural resource utilisation in general. The impacts of climate change on the water resources would lead to other impacts on environmental and socio-economic systems

  13. Biosynthesis, characterization, and antimicrobial applications of silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Singh P

    2015-03-01

    Full Text Available Priyanka Singh,1 Yeon Ju Kim,2 Hina Singh,1 Chao Wang,2 Kyu Hyon Hwang,3 Mohamed El-Agamy Farh,1 Deok Chun Yang1,2 1Department of Oriental Medicinal Material and Processing, 2Graduate School of Biotechnology and Ginseng Bank, College of Life Sciences, Kyung Hee University, Yongin, 3Gyeonggi-Do Agricultural Research & Extension Services, Gyeonggi, Republic of Korea Abstract: In the present study, the strain Brevibacterium frigoritolerans DC2 was explored for the efficient and extracellular synthesis of silver nanoparticles. These biosynthesized silver nanoparticles were characterized by ultraviolet-visible spectrophotometry, which detected the formation of silver nanoparticles in the reaction mixture and showed a maximum absorbance at 420 nm. In addition, field emission transmission electron microscopy revealed the spherical shape of the nanoparticles. The dynamic light scattering results indicated the average particle size of the product was 97 nm with a 0.191 polydispersity index. Furthermore, the product was analyzed by energy dispersive X-ray spectroscopy, X-ray diffraction, and elemental mapping, which displayed the presence of elemental silver in the product. Moreover, on a medical platform, the product was checked against pathogenic microorganisms including Vibrio parahaemolyticus, Salmonella enterica, Bacillus anthracis, Bacillus cereus, Escherichia coli, and Candida albicans. The nanoparticles demonstrated antimicrobial activity against all of these pathogenic microorganisms. Additionally, the silver nanoparticles were evaluated for their combined effects with the commercial antibiotics lincomycin, oleandomycin, vancomycin, novobiocin, penicillin G, and rifampicin against these pathogenic microorganisms. These results indicated that the combination of antibiotics with biosynthesized silver nanoparticles enhanced the antimicrobial effects of antibiotics. Therefore, the current study is a demonstration of an efficient biological synthesis

  14. Comparative transcriptome reconstruction of four Hypericum species focused on hypericin biosynthesis

    Directory of Open Access Journals (Sweden)

    Miroslav Soták

    2016-07-01

    improve current knowledge about the selected Hypericumspp. with proposed relation to hypericin biosynthesis and will provide a useful resource ofgenomic information for consequential studies in the field of functional genomics, proteomicsand metabolomics.

  15. Dithiolopyrrolone Natural Products: Isolation, Synthesis and Biosynthesis

    Science.gov (United States)

    Qin, Zhiwei; Huang, Sheng; Yu, Yi; Deng, Hai

    2013-01-01

    Dithiolopyrrolones are a class of antibiotics that possess the unique pyrrolinonodithiole (4H-[1,2] dithiolo [4,3-b] pyrrol-5-one) skeleton linked to two variable acyl groups. To date, there are approximately 30 naturally occurring dithiolopyrrolone compounds, including holomycin, thiolutin, and aureothricin, and more recently thiomarinols, a unique class of hybrid marine bacterial natural products containing a dithiolopyrrolone framework linked by an amide bridge with an 8-hydroxyoctanoyl chain linked to a monic acid. Generally, dithiolopyrrolone antibiotics have broad-spectrum antibacterial activity against various microorganisms, including Gram-positive and Gram-negative bacteria, and even parasites. Holomycin appeared to be active against rifamycin-resistant bacteria and also inhibit the growth of the clinical pathogen methicillin-resistant Staphylococcus aureus N315. Its mode of action is believed to inhibit RNA synthesis although the exact mechanism has yet to be established in vitro. A recent work demonstrated that the fish pathogen Yersinia ruckeri employs an RNA methyltransferase for self-resistance during the holomycin production. Moreover, some dithiolopyrrolone derivatives have demonstrated promising antitumor activities. The biosynthetic gene clusters of holomycin have recently been identified in S. clavuligerus and characterized biochemically and genetically. The biosynthetic gene cluster of thiomarinol was also identified from the marine bacterium Pseudoalteromonas sp. SANK 73390, which was uniquely encoded by two independent pathways for pseudomonic acid and pyrrothine in a novel plasmid. The aim of this review is to give an overview about the isolations, characterizations, synthesis, biosynthesis, bioactivities and mode of action of this unique family of dithiolopyrrolone natural products, focusing on the period from 1940s until now. PMID:24141227

  16. Biosynthesis of 2'-deoxycoformycin by Streptomyces antibioticus

    International Nuclear Information System (INIS)

    Hanvey, J.C.

    1986-01-01

    The biosynthesis of 2'-deoxycoformycin by Streptomyces antibioticus has been investigated. Previous studies indicated that a purine nycleoside is the precursor for ten of the eleven carbons of deoxycoformycin. It was proposed that carbon-7 of the seven-membered, 1,3-diazepine-ring of deoxycoformycin is not derived from the purine ring but by an insertion of a one-carbon unit between N-1 and C-6 of the purine ring. Carbon-1 of D-ribose has now been identified as the precursor for carbon 7 (and 1') of deoxycoformycin. Although the tetrahydrofolate/one-carbon pool contributes one carbon units to carbons-2 and 8 of the purine ring, which become carbons-5 and 2 of deoxycoformycin, it is not involved in the formation of carbon-7. The retention of the tritium on carbon-2 of [2,8- 3 H]-adenosine in deoxycoformycin indicates that guanosine is not the nucleoside precursor of deoxycoformycin. The failure to detect the incorporation of 18 O from [6- 18 O]-inosine in deoxycoformycin suggests that inosine is not the purine nucleoside precursor of deoxycoformycin. Therefore, it is proposed that adenosine and carbon-1 and d-ribose are the carbon-nitrogen precursors of deoxycoformycin. A mechanism for the insertion of carbon-1 of d-ribose into the pyrimidine portion of the purine ring has been proposed. Using cell-free extracts of S. antibioticus, 8-ketodeoxycoformycin and 8-ketocoformycin can be converted to deoxycoformycin and coformycin, respectively. The enzyme which reduces the 8-keto groups has been characterized and partially purified

  17. Cohort profile of the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Case Register: current status and recent enhancement of an Electronic Mental Health Record-derived data resource.

    Science.gov (United States)

    Perera, Gayan; Broadbent, Matthew; Callard, Felicity; Chang, Chin-Kuo; Downs, Johnny; Dutta, Rina; Fernandes, Andrea; Hayes, Richard D; Henderson, Max; Jackson, Richard; Jewell, Amelia; Kadra, Giouliana; Little, Ryan; Pritchard, Megan; Shetty, Hitesh; Tulloch, Alex; Stewart, Robert

    2016-03-01

    The South London and Maudsley National Health Service (NHS) Foundation Trust Biomedical Research Centre (SLaM BRC) Case Register and its Clinical Record Interactive Search (CRIS) application were developed in 2008, generating a research repository of real-time, anonymised, structured and open-text data derived from the electronic health record system used by SLaM, a large mental healthcare provider in southeast London. In this paper, we update this register's descriptive data, and describe the substantial expansion and extension of the data resource since its original development. Descriptive data were generated from the SLaM BRC Case Register on 31 December 2014. Currently, there are over 250,000 patient records accessed through CRIS. Since 2008, the most significant developments in the SLaM BRC Case Register have been the introduction of natural language processing to extract structured data from open-text fields, linkages to external sources of data, and the addition of a parallel relational database (Structured Query Language) output. Natural language processing applications to date have brought in new and hitherto inaccessible data on cognitive function, education, social care receipt, smoking, diagnostic statements and pharmacotherapy. In addition, through external data linkages, large volumes of supplementary information have been accessed on mortality, hospital attendances and cancer registrations. Coupled with robust data security and governance structures, electronic health records provide potentially transformative information on mental disorders and outcomes in routine clinical care. The SLaM BRC Case Register continues to grow as a database, with approximately 20,000 new cases added each year, in addition to extension of follow-up for existing cases. Data linkages and natural language processing present important opportunities to enhance this type of research resource further, achieving both volume and depth of data. However, research projects still

  18. Abnormal Ergosterol Biosynthesis Activates Transcriptional Responses to Antifungal Azoles.

    Science.gov (United States)

    Hu, Chengcheng; Zhou, Mi; Wang, Wenzhao; Sun, Xianyun; Yarden, Oded; Li, Shaojie

    2018-01-01

    Fungi transcriptionally upregulate expression of azole efflux pumps and ergosterol biosynthesis pathway genes when exposed to antifungal agents that target ergosterol biosynthesis. To date, these transcriptional responses have been shown to be dependent on the presence of the azoles and/or depletion of ergosterol. Using an inducible promoter to regulate Neurospora crassa erg11 , which encodes the major azole target, sterol 14α-demethylase, we were able to demonstrate that the CDR4 azole efflux pump can be transcriptionally activated by ergosterol biosynthesis inhibition even in the absence of azoles. By analyzing ergosterol deficient mutants, we demonstrate that the transcriptional responses by cdr4 and, unexpectedly, genes encoding ergosterol biosynthesis enzymes ( erg genes) that are responsive to azoles, are not dependent on ergosterol depletion. Nonetheless, deletion of erg2 , which encodes C-8 sterol isomerase, also induced expression of cdr4 . Deletion of erg2 also induced the expression of erg24 , the gene encoding C-14 sterol reductase, but not other tested erg genes which were responsive to erg11 inactivation. This indicates that inhibition of specific steps of ergosterol biosynthesis can result in different transcriptional responses, which is further supported by our results obtained using different ergosterol biosynthesis inhibitors. Together with the sterol profiles, these results suggest that the transcriptional responses by cdr4 and erg genes are associated with accumulation of specific sterol intermediate(s). This was further supported by the fact that when the erg2 mutant was treated with ketoconazole, upstream inhibition overrode the effects by downstream inhibition on ergosterol biosynthesis pathway. Even though cdr4 expression is associated with the accumulation of sterol intermediates, intra- and extracellular sterol analysis by HPLC-MS indicated that the transcriptional induction of cdr4 did not result in efflux of the accumulated intermediate

  19. Application of statistical experimental design for optimization of silver nanoparticles biosynthesis by a nanofactory Streptomyces viridochromogenes.

    Science.gov (United States)

    El-Naggar, Noura El-Ahmady; Abdelwahed, Nayera A M

    2014-01-01

    Central composite design was chosen to determine the combined effects of four process variables (AgNO3 concentration, incubation period, pH level and inoculum size) on the extracellular biosynthesis of silver nanoparticles (AgNPs) by Streptomyces viridochromogenes. Statistical analysis of the results showed that incubation period, initial pH level and inoculum size had significant effects (Pbiosynthesis of silver nanoparticles at their individual level. The maximum biosynthesis of silver nanoparticles was achieved at a concentration of 0.5% (v/v) of 1 mM AgNO3, incubation period of 96 h, initial pH of 9 and inoculum size of 2% (v/v). After optimization, the biosynthesis of silver nanoparticles was improved by approximately 5-fold as compared to that of the unoptimized conditions. The synthetic process of silver nanoparticle generation using the reduction of aqueous Ag+ ion by the culture supernatants of S. viridochromogenes was quite fast, and silver nanoparticles were formed immediately by the addition of AgNO3 solution (1 mM) to the cell-free supernatant. Initial characterization of silver nanoparticles was performed by visual observation of color change from yellow to intense brown color. UV-visible spectrophotometry for measuring surface plasmon resonance showed a single absorption peak at 400 nm, which confirmed the presence of silver nanoparticles. Fourier Transform Infrared Spectroscopy analysis provided evidence for proteins as possible reducing and capping agents for stabilizing the nanoparticles. Transmission Electron Microscopy revealed the extracellular formation of spherical silver nanoparticles in the size range of 2.15-7.27 nm. Compared to the cell-free supernatant, the biosynthesized AgNPs revealed superior antimicrobial activity against Gram-negative, Gram-positive bacterial strains and Candida albicans.

  20. Jasmonate-induced biosynthesis of andrographolide in Andrographis paniculata.

    Science.gov (United States)

    Sharma, Shiv Narayan; Jha, Zenu; Sinha, Rakesh Kumar; Geda, Arvind Kumar

    2015-02-01

    Andrographolide is a prominent secondary metabolite found in Andrographis paniculata that exhibits enormous pharmacological effects. In spite of immense value, the normal biosynthesis of andrographolide results in low amount of the metabolite. To induce the biosynthesis of andrographolide, we attempted elicitor-induced activation of andrographolide biosynthesis in cell cultures of A. paniculata. This was carried out by using methyl jasmonate (MeJA) as an elicitor. Among the various concentrations of MeJA tested at different time periods, 5 µM MeJA yielded 5.25 times more andrographolide content after 24 h of treatment. The accumulation of andrographolide was correlated with the expression level of known regulatory genes (hmgs, hmgr, dxs, dxr, isph and ggps) of mevalonic acid (MVA) and 2-C-methyl-d-erythritol-4-phosphate (MEP) pathways. These results established the involvement of MeJA in andrographolide biosynthesis by inducing the transcription of its biosynthetic pathways genes. The coordination of isph, ggps and hmgs expression highly influenced the andrographolide biosynthesis. © 2014 Scandinavian Plant Physiology Society.

  1. Biosynthesis and functions of sulfur modifications in tRNA

    Directory of Open Access Journals (Sweden)

    Naoki eShigi

    2014-04-01

    Full Text Available Sulfur is an essential element for a variety of cellular constituents in all living organisms. In tRNA molecules, there are many sulfur-containing nucleosides, such as the derivatives of 2‑thiouridine (s2U, 4-thiouridine (s4U, 2-thiocytidine (s2C, and 2-methylthioadenosine (ms2A. Earlier studies established the functions of these modifications for accurate and efficient translation, including proper recognition of the codons in mRNA or stabilization of tRNA structure. In many cases, the biosynthesis of these sulfur modifications starts with cysteine desulfurases, which catalyze the generation of persulfide (an activated form of sulfur from cysteine. Many sulfur-carrier proteins are responsible for delivering this activated sulfur to each biosynthesis pathway. Finally, specific modification enzymes activate target tRNAs and then incorporate sulfur atoms. Intriguingly, the biosynthesis of 2-thiouridine in all domains of life is functionally and evolutionarily related to the ubiquitin-like post-translational modification system of cellular proteins in eukaryotes. This review summarizes the recent characterization of the biosynthesis of sulfur modifications in tRNA and the novel roles of this modification in cellular functions in various model organisms, with a special emphasis on 2-thiouridine derivatives. Each biosynthesis pathway of sulfur-containing molecules is mutually modulated via sulfur trafficking, and 2-thiouridine and codon usage bias have been proposed to control the translation of specific genes.

  2. [Biosynthesis of gold nanoparticles by Azospirillum brasilense].

    Science.gov (United States)

    Kupriashina, M A; Vetchinkina, E P; Burov, A M; Ponomareva, E G; Nikitina, V E

    2014-01-01

    Plant-associated nitrogen-fixing soil bacteria Azospirillum brasilense were shown to reduce the gold of chloroauric acid to elemental gold, resulting in formation of gold nanoparicles. Extracellular phenoloxidizing enzymes (laccases and Mn peroxidases) were shown to participate in reduction of Au+3 (HAuCl4) to Au(0). Transmission electron microscopy revealed accumulation of colloidal gold nanoparticles of diverse shape in the culture liquid of A. brasilense strains Sp245 and Sp7. The size of the electron-dense nanospheres was 5 to 50 nm, and the size of nanoprisms varied from 5 to 300 nm. The tentative mechanism responsible for formation of gold nanoparticles is discussed.

  3. Current Models for Transcriptional Regulation of Secondary Cell Wall Biosynthesis in Grasses

    Directory of Open Access Journals (Sweden)

    Xiaolan Rao

    2018-04-01

    Full Text Available Secondary cell walls mediate many crucial biological processes in plants including mechanical support, water and nutrient transport and stress management. They also provide an abundant resource of renewable feed, fiber, and fuel. The grass family contains the most important food, forage, and biofuel crops. Understanding the regulatory mechanism of secondary wall formation in grasses is necessary for exploiting these plants for agriculture and industry. Previous research has established a detailed model of the secondary wall regulatory network in the dicot model species Arabidopsis thaliana. Grasses, branching off from the dicot ancestor 140–150 million years ago, display distinct cell wall morphology and composition, suggesting potential for a different secondary wall regulation program from that established for dicots. Recently, combined application of molecular, genetic and bioinformatics approaches have revealed more transcription factors involved in secondary cell wall biosynthesis in grasses. Compared with the dicots, grasses exhibit a relatively conserved but nevertheless divergent transcriptional regulatory program to activate their secondary cell wall development and to coordinate secondary wall biosynthesis with other physiological processes.

  4. Analysis of the transcriptome of Isodon rubescens and key enzymes involved in terpenoid biosynthesis

    Directory of Open Access Journals (Sweden)

    Xiuhong Su

    2016-05-01

    Full Text Available Isodon rubescens is an important medicinal plant in China that has been shown to reduce tumour growth due to the presence of the compound oridonin. In an effort to facilitate molecular research on oridonin biosynthesis, we reported the use of next generation massively parallel sequencing technologies and de novo transcriptome assembly to gain a comprehensive overview of I. rubescens transcriptome. In our study, a total of 50,934,276 clean reads, 101,640 transcripts and 44,626 unigenes were generated through de novo transcriptome assembly. A number of unigenes – 23,987, 10,263, 7359, 18,245, 17,683, 19,485, 9361 – were annotated in the National Center for Biotechnology Information (NCBI non-redundant protein (Nr, NCBI nucleotide sequences (Nt, Kyoto Encyclopedia of Genes and Genomes (KEGG Orthology (KO, Swiss-Prot, protein family (Pfam, gene ontology (GO, eukaryotic ortholog groups (KOG databases, respectively. Furthermore, the annotated unigenes were functionally classified according to the GO, KOG and KEGG. Based on these results, candidate genes encoding enzymes involved in terpenoids backbone biosynthesis were detected. Our data provided the most comprehensive sequence resource available for the study on I. rubescens, as well as demonstrated the effective use of Illumina sequencing and de novo transcriptome assembly on a species lacking genomic information.

  5. The pomegranate (Punica granatum L.) genome and the genomics of punicalagin biosynthesis.

    Science.gov (United States)

    Qin, Gaihua; Xu, Chunyan; Ming, Ray; Tang, Haibao; Guyot, Romain; Kramer, Elena M; Hu, Yudong; Yi, Xingkai; Qi, Yongjie; Xu, Xiangyang; Gao, Zhenghui; Pan, Haifa; Jian, Jianbo; Tian, Yinping; Yue, Zhen; Xu, Yiliu

    2017-09-01

    Pomegranate (Punica granatum L.) is a perennial fruit crop grown since ancient times that has been planted worldwide and is known for its functional metabolites, particularly punicalagins. We have sequenced and assembled the pomegranate genome with 328 Mb anchored into nine pseudo-chromosomes and annotated 29 229 gene models. A Myrtales lineage-specific whole-genome duplication event was detected that occurred in the common ancestor before the divergence of pomegranate and Eucalyptus. Repetitive sequences accounted for 46.1% of the assembled genome. We found that the integument development gene INNER NO OUTER (INO) was under positive selection and potentially contributed to the development of the fleshy outer layer of the seed coat, an edible part of pomegranate fruit. The genes encoding the enzymes for synthesis and degradation of lignin, hemicelluloses and cellulose were also differentially expressed between soft- and hard-seeded varieties, reflecting differences in their accumulation in cultivars differing in seed hardness. Candidate genes for punicalagin biosynthesis were identified and their expression patterns indicated that gallic acid synthesis in tissues could follow different biochemical pathways. The genome sequence of pomegranate provides a valuable resource for the dissection of many biological and biochemical traits and also provides important insights for the acceleration of breeding. Elucidation of the biochemical pathway(s) involved in punicalagin biosynthesis could assist breeding efforts to increase production of this bioactive compound. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  6. Model for Presenting Resources in Scholar's Portal

    Science.gov (United States)

    Feeney, Mary; Newby, Jill

    2005-01-01

    Presenting electronic resources to users through a federated search engine introduces unique opportunities and challenges to libraries. This article reports on the decision-making tools and processes used for selecting collections of electronic resources by a project team at the University of Arizona (UA) Libraries for the Association of Research…

  7. Diabetes - resources

    Science.gov (United States)

    Resources - diabetes ... The following sites provide further information on diabetes: American Diabetes Association -- www.diabetes.org Juvenile Diabetes Research Foundation International -- www.jdrf.org National Center for Chronic Disease Prevention and Health Promotion -- ...

  8. Hemophilia - resources

    Science.gov (United States)

    Resources - hemophilia ... The following organizations provide further information on hemophilia : Centers for Disease Control and Prevention -- www.cdc.gov/ncbddd/hemophilia/index.html National Heart, Lung, and Blood Institute -- www.nhlbi.nih.gov/ ...

  9. Seaweed resources

    Digital Repository Service at National Institute of Oceanography (India)

    Deshmukhe, G.V.; Dhargalkar, V.K.; Untawale, A.G.

    The chapter summarizes our present knowledge of the seaweed resources of the Indian Ocean region with regard to the phytogeographical distribution, composition, biomass, utilization, cultivation, conservation and management. The voluminous data...

  10. Mineral resources

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.

    to the source, supply rate, sediment type and seabed topography. Indian Ocean is second largest and least explored for nonrenewable resources. Compared to deep-sea, relatively better knowledge is available for the near shore deposits. A concise account...

  11. Depression - resources

    Science.gov (United States)

    Resources - depression ... Depression is a medical condition. If you think you may be depressed, see a health care provider. ... following organizations are good sources of information on depression : American Psychological Association -- www.apa.org/topics/depression/ ...

  12. Arthritis - resources

    Science.gov (United States)

    Resources - arthritis ... The following organizations provide more information on arthritis : American Academy of Orthopaedic Surgeons -- orthoinfo.aaos.org/menus/arthritis.cfm Arthritis Foundation -- www.arthritis.org Centers for Disease Control and Prevention -- www. ...

  13. Regulation of anthocyanin biosynthesis in peach fruits.

    Science.gov (United States)

    Rahim, Md Abdur; Busatto, Nicola; Trainotti, Livio

    2014-11-01

    MYB10.1 and MYB10.3, with bHLH3, are the likely regulators of anthocyanin biosynthesis in peach fruit. MYB10.1/2/3 forms a cluster on the same genomic fragment where the Anther color ( Ag ) trait is located. Anthocyanins are bioactive compounds responsible for the pigmentation of many plant parts such as leaves, flowers, fruits and roots, and have potential benefits to human health. In peach [Prunus persica (L.) Batsch], peel color is a key determinant for fruit quality and is regulated by flavonoids including anthocyanins. The R2R3 MYB transcription factors (TFs) control the expression of anthocyanin biosynthetic genes with the help of co-activators belonging to the basic-helix-loop-helix (bHLH) and WD40 repeat families. In the peach genome six MYB10-like and three bHLH-like TFs were identified as candidates to be the regulators of the anthocyanin accumulation, which, in yellow flesh fruits, is highest in the peel, abundant in the part of the mesocarp surrounding the stone and lowest in the mesocarp. The expression of MYB10.1 and MYB10.3 correlates with anthocyanin levels of different peach parts. They also have positive correlation with the expression of key structural genes of the anthocyanin pathway, such as CHS, F3H, and UFGT. Functions of peach MYB10s were tested in tobacco and shown to activate key genes in the anthocyanin pathway when bHLHs were co-expressed as partners. Overexpression of MYB10.1/bHLH3 and MYB10.3/bHLH3 activated anthocyanin production by up-regulating NtCHS, NtDFR and NtUFGT while other combinations were not, or much less, effective. As three MYB10 genes are localized in a genomic region where the Ag trait, responsible for anther pigmentation, is localized, it is proposed they are key determinant to introduce new peach cultivars with higher antioxidant level and pigmented fruit.

  14. Forest Resources

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    Forest biomass is an abundant biomass feedstock that complements the conventional forest use of wood for paper and wood materials. It may be utilized for bioenergy production, such as heat and electricity, as well as for biofuels and a variety of bioproducts, such as industrial chemicals, textiles, and other renewable materials. The resources within the 2016 Billion-Ton Report include primary forest resources, which are taken directly from timberland-only forests, removed from the land, and taken to the roadside.

  15. Purine Biosynthesis Metabolically Constrains Intracellular Survival of Uropathogenic Escherichia coli

    Science.gov (United States)

    Shaffer, Carrie L.; Zhang, Ellisa W.; Dudley, Anne G.; Dixon, Beverly R. E. A.; Guckes, Kirsten R.; Breland, Erin J.; Floyd, Kyle A.; Casella, Daniel P.; Algood, Holly M. Scott; Clayton, Douglass B.

    2016-01-01

    ABSTRACT The ability to de novo synthesize purines has been associated with the intracellular survival of multiple bacterial pathogens. Uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections, undergoes a transient intracellular lifestyle during which bacteria clonally expand into multicellular bacterial communities within the cytoplasm of bladder epithelial cells. Here, we characterized the contribution of the conserved de novo purine biosynthesis-associated locus cvpA-purF to UPEC pathogenesis. Deletion of cvpA-purF, or of purF alone, abolished de novo purine biosynthesis but did not impact bacterial adherence properties in vitro or in the bladder lumen. However, upon internalization by bladder epithelial cells, UPEC deficient in de novo purine biosynthesis was unable to expand into intracytoplasmic bacterial communities over time, unless it was extrachromosomally complemented. These findings indicate that UPEC is deprived of purine nucleotides within the intracellular niche and relies on de novo purine synthesis to meet this metabolic requirement. PMID:27795353

  16. NAD+ biosynthesis, aging, and disease [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Sean Johnson

    2018-02-01

    Full Text Available Nicotinamide adenine dinucleotide (NAD+ biosynthesis and its regulation have recently been attracting markedly increasing interest. Aging is marked by a systemic decrease in NAD+ across multiple tissues. The dysfunction of NAD+ biosynthesis plays a critical role in the pathophysiologies of multiple diseases, including age-associated metabolic disorders, neurodegenerative diseases, and mental disorders. As downstream effectors, NAD+-dependent enzymes, such as sirtuins, are involved in the progression of such disorders. These recent studies implicate NAD+ biosynthesis as a potential target for preventing and treating age-associated diseases. Indeed, new studies have demonstrated the therapeutic potential of supplementing NAD+ intermediates, such as nicotinamide mononucleotide and nicotinamide riboside, providing a proof of concept for the development of an effective anti-aging intervention.

  17. Zincophorin – biosynthesis in Streptomyces griseus and antibiotic properties

    Directory of Open Access Journals (Sweden)

    Walther, Elisabeth

    2016-11-01

    Full Text Available Zincophorin is a polyketide antibiotic that possesses potent activity against Gram-positive bacteria, including human pathogens. While a number of total syntheses of this highly functionalized natural product were reported since its initial discovery, the genetic basis for the biosynthesis of zincophorin has remained unclear. In this study, the co-linearity inherent to polyketide pathways was used to identify the zincophorin biosynthesis gene cluster in the genome of the natural producer HKI 0741. Interestingly, the same locus is fully conserved in the streptomycin-producing actinomycete IFO 13350, suggesting that the latter bacterium is also capable of zincophorin biosynthesis. Biological profiling of zincophorin revealed a dose-dependent inhibition of the Gram-positive bacterium . The antibacterial effect, however, is accompanied by cytotoxicity. Antibiotic and cytotoxic activities were completely abolished upon esterification of the carboxylic acid group in zincophorin.

  18. Genes Involved in the Biosynthesis and Transport of Acinetobactin in

    Directory of Open Access Journals (Sweden)

    Tarik Hasan

    2015-03-01

    Full Text Available Pathogenic bacteria survive in iron-limited host environments by using several iron acquisition mechanisms. Acinetobacter baumannii, causing serious infections in compromised patients, produces an iron-chelating molecule, called acinetobactin, which is composed of equimolar quantities of 2,3-dihydroxybenzoic acid (DHBA, L-threonine, and N-hydroxyhistamine, to compete with host cells for iron. Genes that are involved in the production and transport of acinetobactin are clustered within the genome of A. baumannii. A recent study showed that entA, located outside of the acinetobactin gene cluster, plays important roles in the biosynthesis of the acinetobactin precursor DHBA and in bacterial pathogenesis. Therefore, understanding the genes that are associated with the biosynthesis and transport of acinetobactin in the bacterial genome is required. This review is intended to provide a general overview of the genes in the genome of A. baumannii that are required for acinetobactin biosynthesis and transport.

  19. Inhibitors of amino acids biosynthesis as antifungal agents.

    Science.gov (United States)

    Jastrzębowska, Kamila; Gabriel, Iwona

    2015-02-01

    Fungal microorganisms, including the human pathogenic yeast and filamentous fungi, are able to synthesize all proteinogenic amino acids, including nine that are essential for humans. A number of enzymes catalyzing particular steps of human-essential amino acid biosynthesis are fungi specific. Numerous studies have shown that auxotrophic mutants of human pathogenic fungi impaired in biosynthesis of particular amino acids exhibit growth defect or at least reduced virulence under in vivo conditions. Several chemical compounds inhibiting activity of one of these enzymes exhibit good antifungal in vitro activity in minimal growth media, which is not always confirmed under in vivo conditions. This article provides a comprehensive overview of the present knowledge on pathways of amino acids biosynthesis in fungi, with a special emphasis put on enzymes catalyzing particular steps of these pathways as potential targets for antifungal chemotherapy.

  20. Some aspects of genetic control of antibiotic biosynthesis in Streptomyces

    Directory of Open Access Journals (Sweden)

    М. P. Teplitskaya

    2005-12-01

    Full Text Available These work contain a review of basic hypotheses and experimental information in relation to the problem of antibiotic synthesis regulation by the bacteria of the Streptomyces family. Data on cluster organization of antibiotics biosynthesis genes in these microorganisms were generalized. The examples of the positive and negative specific control of antibiotic production genes were resulted. Except for it, proofs that confirm participation of a few genes of more high level in the process of initiation and expression of antibiotics biosynthesis genes also were found. In this connection А-factor role in the mechanism of cascade-organized process of streptomycin biosynthesis control, some other antibiotics and spore determinations is discussed in detail.

  1. Tannin biosynthesis of iron oxide nanoparticles

    Science.gov (United States)

    Herrera-Becerra, R.; Rius, J. L.; Zorrilla, C.

    2010-08-01

    In this work, iron oxide nanoparticles synthesized with gallic acid and tannic acid are characterized using High-Resolution Transmission Electron Microscopy (HRTEM). Its size, form, and structure are compared with nanoparticles obtained previously using alfalfa biomass in order to find a simpler, consistent, and environmentally friendly method in the production of iron oxide nanoparticles.

  2. Recent advances in combinatorial biosynthesis for drug discovery

    Directory of Open Access Journals (Sweden)

    Sun H

    2015-02-01

    Full Text Available Huihua Sun,1,* Zihe Liu,1,* Huimin Zhao,1,2 Ee Lui Ang1 1Metabolic Engineering Research Laboratory, Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research, Singapore; 2Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA *These authors contributed equally to this work Abstract: Because of extraordinary structural diversity and broad biological activities, natural products have played a significant role in drug discovery. These therapeutically important secondary metabolites are assembled and modified by dedicated biosynthetic pathways in their host living organisms. Traditionally, chemists have attempted to synthesize natural product analogs that are important sources of new drugs. However, the extraordinary structural complexity of natural products sometimes makes it challenging for traditional chemical synthesis, which usually involves multiple steps, harsh conditions, toxic organic solvents, and byproduct wastes. In contrast, combinatorial biosynthesis exploits substrate promiscuity and employs engineered enzymes and pathways to produce novel “unnatural” natural products, substantially expanding the structural diversity of natural products with potential pharmaceutical value. Thus, combinatorial biosynthesis provides an environmentally friendly way to produce natural product analogs. Efficient expression of the combinatorial biosynthetic pathway in genetically tractable heterologous hosts can increase the titer of the compound, eventually resulting in less expensive drugs. In this review, we will discuss three major strategies for combinatorial biosynthesis: 1 precursor-directed biosynthesis; 2 enzyme-level modification, which includes swapping of the entire domains, modules and subunits, site-specific mutagenesis, and directed evolution; 3 pathway-level recombination. Recent examples of combinatorial biosynthesis employing these

  3. Plant tolerance to excess light energy and photooxidative damage relies on plastoquinone biosynthesis.

    Science.gov (United States)

    Ksas, Brigitte; Becuwe, Noëlle; Chevalier, Anne; Havaux, Michel

    2015-06-03

    Plastoquinone-9 is known as a photosynthetic electron carrier to which has also been attributed a role in the regulation of gene expression and enzyme activities via its redox state. Here, we show that it acts also as an antioxidant in plant leaves, playing a central photoprotective role. When Arabidopsis plants were suddenly exposed to excess light energy, a rapid consumption of plastoquinone-9 occurred, followed by a progressive increase in concentration during the acclimation phase. By overexpressing the plastoquinone-9 biosynthesis gene SPS1 (solanesyl diphosphate synthase 1) in Arabidopsis, we succeeded in generating plants that specifically accumulate plastoquinone-9 and its derivative plastochromanol-8. The SPS1-overexpressing lines were much more resistant to photooxidative stress than the wild type, showing marked decreases in leaf bleaching, lipid peroxidation and PSII photoinhibition under excess light. Comparison of the SPS1 overexpressors with other prenyl quinone mutants indicated that the enhanced phototolerance of the former plants is directly related to their increased capacities for plastoquinone-9 biosynthesis.

  4. Biosynthesis of silver nanoparticles using Euglena gracilis, Euglena intermedia and their extract.

    Science.gov (United States)

    Li, Yong; Tang, Xiaoling; Song, Wenshuang; Zhu, Lina; Liu, Xingang; Yan, Xiaomin; Jin, Chengzhi; Ren, Qingguang

    2015-02-01

    Extracellular and intracellular biosynthesis of silver nanoparticles (AgNPs) by Euglena gracilis (EG) strain and Euglena intermedia (EI) strain are reported in this study. The obtained nanoparticles showed an absorption peak approximates 420 nm in the UV-visible spectrum, corresponding to the plasmon resonance of AgNPs. According to the result of inductively coupled plasma-atomic emission spectrometer, the intakes of silver ions by EI and EG are roughly equal. The transmission electron microscope (TEM) analysis of the successful in vivo and in vitro synthesised AgNPs indicated the sizes, ranging from 6 to 24 nm and 15 to 60 nm in diameter, respectively, and a spherical-shaped polydispersal of the particles. The successful formation of AgNPs has been confirmed by energy dispersive X-ray analysis connected to the TEM. The Fourier transform infrared spectroscopy measurements reveal the presence of bioactive functional groups such as amines are found to be the capping and stabilising agents of nanoparticles. To our knowledge, this is the first report where two kinds of Euglena microalga were used as the potential source for in vivo and in vitro biosynthesis of AgNPs.

  5. Enhancement of Thiamine Biosynthesis in Oil Palm Seedlings by Colonization of Endophytic Fungus Hendersonia toruloidea.

    Science.gov (United States)

    Kamarudin, Amirah N; Lai, Kok S; Lamasudin, Dhilia U; Idris, Abu S; Balia Yusof, Zetty N

    2017-01-01

    Thiamine, or vitamin B1 plays an indispensable role as a cofactor in crucial metabolic reactions including glycolysis, pentose phosphate pathway and the tricarboxylic acid cycle in all living organisms. Thiamine has been shown to play a role in plant adaptation toward biotic and abiotic stresses. The modulation of thiamine biosynthetic genes in oil palm seedlings was evaluated in response to root colonization by endophytic Hendersonia toruloidea . Seven-month-old oil palm seedlings were inoculated with H. toruloidea and microscopic analyses were performed to visualize the localization of endophytic H. toruloidea in oil palm roots. Transmission electron microscopy confirmed that H. toruloidea colonized cortical cells. The expression of thiamine biosynthetic genes and accumulation of total thiamine in oil palm seedlings were also evaluated. Quantitative real-time PCR was performed to measure transcript abundances of four key thiamine biosynthesis genes ( THI4 , THIC , TH1 , and TPK ) on days 1, 7, 15, and 30 in response to H. toruloidea colonization. The results showed an increase of up to 12-fold in the expression of all gene transcripts on day 1 post-inoculation. On days 7, 15, and 30 post-inoculation, the relative expression levels of these genes were shown to be downregulated. Thiamine accumulation was observed on day 7 post-colonization and subsequently decreased until day 30. This work provides the first evidence for the enhancement of thiamine biosynthesis by endophytic colonization in oil palm seedlings.

  6. Characterization of Human and Yeast Mitochondrial Glycine Carriers with Implications for Heme Biosynthesis and Anemia.

    Science.gov (United States)

    Lunetti, Paola; Damiano, Fabrizio; De Benedetto, Giuseppe; Siculella, Luisa; Pennetta, Antonio; Muto, Luigina; Paradies, Eleonora; Marobbio, Carlo Marya Thomas; Dolce, Vincenza; Capobianco, Loredana

    2016-09-16

    Heme is an essential molecule in many biological processes, such as transport and storage of oxygen and electron transfer as well as a structural component of hemoproteins. Defects of heme biosynthesis in developing erythroblasts have profound medical implications, as represented by sideroblastic anemia. The synthesis of heme requires the uptake of glycine into the mitochondrial matrix where glycine is condensed with succinyl coenzyme A to yield δ-aminolevulinic acid. Herein we describe the biochemical and molecular characterization of yeast Hem25p and human SLC25A38, providing evidence that they are mitochondrial carriers for glycine. In particular, the hem25Δ mutant manifests a defect in the biosynthesis of δ-aminolevulinic acid and displays reduced levels of downstream heme and mitochondrial cytochromes. The observed defects are rescued by complementation with yeast HEM25 or human SLC25A38 genes. Our results identify new proteins in the heme biosynthetic pathway and demonstrate that Hem25p and its human orthologue SLC25A38 are the main mitochondrial glycine transporters required for heme synthesis, providing definitive evidence of their previously proposed glycine transport function. Furthermore, our work may suggest new therapeutic approaches for the treatment of congenital sideroblastic anemia. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Biosynthesis and recovery of rod-shaped tellurium nanoparticles and their bactericidal activities

    Energy Technology Data Exchange (ETDEWEB)

    Zare, Bijan; Faramarzi, Mohammad Ali; Sepehrizadeh, Zargham [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451 Tehran (Iran, Islamic Republic of); Shakibaie, Mojtaba [Department of Pharmacognosy and Biotechnology, School of Pharmacy, Pharmaceutics Research Center, Kerman University of Medical Sciences, P.O. Box 76175-493 Kerman (Iran, Islamic Republic of); Rezaie, Sassan [Department of Medical Biotechnology, School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza, E-mail: shahverd@sina.tums.ac.ir [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451 Tehran (Iran, Islamic Republic of)

    2012-11-15

    Highlights: ► Biosynthesis of rod shape tellurium nanoparticles with a hexagonal crystal structure. ► Extraction procedure for isolation of tellurium nanoparticles from Bacillus sp. BZ. ► Extracted tellurium nanoparticles have good bactericidal activity against some bacteria. -- Abstract: In this study, a tellurium-transforming Bacillus sp. BZ was isolated from the Caspian Sea in northern Iran. The isolate was identified by various tests and 16S rDNA analysis, and then used to prepare elemental tellurium nanoparticles. The isolate was subsequently used for the intracellular biosynthesis of elemental tellurium nanoparticles. The biogenic nanoparticles were released by liquid nitrogen and purified by an n-octyl alcohol water extraction system. The shape, size, and composition of the extracted nanoparticles were characterized. The transmission electron micrograph showed rod-shaped nanoparticles with dimensions of about 20 nm × 180 nm. The energy dispersive X-ray and X-ray diffraction spectra respectively demonstrated that the extracted nanoparticles consisted of only tellurium and have a hexagonal crystal structure. This is the first study to demonstrate a biological method for synthesizing rod-shaped elemental tellurium by a Bacillus sp., its extraction and its antibacterial activity against different clinical isolates.

  8. Biosynthesis of silver nanoparticles using Moringa oleifera leaf extract and its application to optical limiting.

    Science.gov (United States)

    Sathyavathi, R; Krishna, M Bala Murali; Rao, D Narayana

    2011-03-01

    The Development of biologically inspired experimental processes for the synthesis of nanoparticles is evolving into an important branch of nanotechnology. The work presented here with the biosynthesis of silver nanoparticles using Moringa oleifera leaf extract as reducing and stabilizing agent and its application in nonlinear optics. The aqueous silver ions when exposed to Moringa oleifera leaf extract are reduced resulting in silver nanoparticles demonstrating the biosynthesis. The silver nanoparticles were characterized by UV-Visible, X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR) and transmission electron microscopy (TEM) techniques. TEM analysis shows a dispersion of the nanoparticles in a range of 5-80 nm with the average around 46 nm and are crystallized in face centred cubic symmetry. To show that these biosynthesized silver nanoparticles possess very good nonlinear properties similar to those nanoparticles synthesized by chemical route, we carried out the Z-scan studies with a 6 ns, 532 nm pulsed laser. We estimated the nonlinear absorption coefficient and compare it with the literature values of the nanoparticles synthesized through chemical route. The silver nanoparticles suspended in solution exhibited reverse saturable absorption with optical limiting threshold of 100 mJ/cm2.

  9. Biosynthesis of Bacterial Cellulose/Carboxylic Multi-Walled Carbon Nanotubes for Enzymatic Biofuel Cell Application

    Directory of Open Access Journals (Sweden)

    Pengfei Lv

    2016-03-01

    Full Text Available Novel nanocomposites comprised of bacterial cellulose (BC with carboxylic multi-walled carbon nanotubes (c-MWCNTs incorporated into the BC matrix were prepared through a simple method of biosynthesis. The biocathode and bioanode for the enzyme biological fuel cell (EBFC were prepared using BC/c-MWCNTs composite injected by laccase (Lac and glucose oxidase (GOD with the aid of glutaraldehyde (GA crosslinking. Biosynthesis of BC/c-MWCNTs composite was characterized by digital photos, scanning electron microscope (SEM, and Fourier Transform Infrared (FTIR. The experimental results indicated the successful incorporation of c-MWCNTs into the BC. The electrochemical and biofuel performance were evaluated by cyclic voltammetry (CV and linear sweep voltammetry (LSV. The power density and current density of EBFCs were recorded at 32.98 µW/cm3 and 0.29 mA/cm3, respectively. Additionally, the EBFCs also showed acceptable stability. Preliminary tests on double cells indicated that renewable BC have great potential in the application field of EBFCs.

  10. Highly efficient in vitro biosynthesis of silver nanoparticles using Lysinibacillus sphaericus MR-1 and their characterization

    Science.gov (United States)

    Gou, Yujun; Zhou, Rongying; Ye, Xiujuan; Gao, Shanshan; Li, Xiangqian

    2015-02-01

    Silver nanoparticles (AgNPs) have been widely used in diverse fields due to their superior properties. Currently the biosynthesis of AgNPs is in the limelight of modern nanotechnology because of its green properties. However, relatively low yield and inefficiency diminish the prospect of applying these biosynthesized AgNPs. In this work, a rapid mass AgNP biosynthesis method using the cell-free extract of a novel bacterial strain, Lysinibacillus sphaericus MR-1, which has been isolated from a chemical fertilizer plant, is reported. In addition, the optimum synthesis conditions of AgNPs were investigated. The optimum pH, temperature, dosage, and reaction time were 12, 70 °C, 20 mM AgNO3, and 75 min, respectively. Finally, AgNPs were characterized by optical absorption spectroscopy, zeta potential and size distribution analysis, x-ray diffraction, electron microscopy, and energy-dispersive x-ray spectroscopy. The results revealed that these biosynthesized AgNPs were bimolecular covered, stable, well-dispersed face centered cubic (fcc) spherical crystalline particles with diameters in the range 5-20 nm. The advantages of this approach are its simplicity, high efficiency, and eco-friendly and cost-effective features.

  11. Transcriptome analysis of Panax vietnamensis var. fuscidicus discovers putative ocotillol-type ginsenosides biosynthesis genes and genetic markers.

    Science.gov (United States)

    Zhang, Guang-Hui; Ma, Chun-Hua; Zhang, Jia-Jin; Chen, Jun-Wen; Tang, Qing-Yan; He, Mu-Han; Xu, Xiang-Zeng; Jiang, Ni-Hao; Yang, Sheng-Chao

    2015-03-08

    liquid chromatography (HPLC) and evaporative light scattering detector (ELSD). The genomic resources generated from P. vietnamensis var. fuscidiscus provide new insights into the identification of putative genes involved in triterpenoid saponins biosynthesis pathway. This will facilitate our understanding of the biosynthesis of triterpenoid saponins at molecular level. The SSR markers identified and developed in this study show genetic diversity for this important crop and will contribute to marker-assisted breeding for P. vietnamensis var. fuscidiscus.

  12. Flavonoid Biosynthesis Genes Putatively Identified in the Aromatic Plant Polygonum minus via Expressed Sequences Tag (EST Analysis

    Directory of Open Access Journals (Sweden)

    Zamri Zainal

    2012-02-01

    Full Text Available P. minus is an aromatic plant, the leaf of which is widely used as a food additive and in the perfume industry. The leaf also accumulates secondary metabolites that act as active ingredients such as flavonoid. Due to limited genomic and transcriptomic data, the biosynthetic pathway of flavonoids is currently unclear. Identification of candidate genes involved in the flavonoid biosynthetic pathway will significantly contribute to understanding the biosynthesis of active compounds. We have constructed a standard cDNA library from P. minus leaves, and two normalized full-length enriched cDNA libraries were constructed from stem and root organs in order to create a gene resource for the biosynthesis of secondary metabolites, especially flavonoid biosynthesis. Thus, large‑scale sequencing of P. minus cDNA libraries identified 4196 expressed sequences tags (ESTs which were deposited in dbEST in the National Center of Biotechnology Information (NCBI. From the three constructed cDNA libraries, 11 ESTs encoding seven genes were mapped to the flavonoid biosynthetic pathway. Finally, three flavonoid biosynthetic pathway-related ESTs chalcone synthase, CHS (JG745304, flavonol synthase, FLS (JG705819 and leucoanthocyanidin dioxygenase, LDOX (JG745247 were selected for further examination by quantitative RT-PCR (qRT-PCR in different P. minus organs. Expression was detected in leaf, stem and root. Gene expression studies have been initiated in order to better understand the underlying physiological processes.

  13. Deep sequencing of Lotus corniculatus L. reveals key enzymes and potential transcription factors related to the flavonoid biosynthesis pathway.

    Science.gov (United States)

    Wang, Ying; Hua, Wenping; Wang, Jian; Hannoufa, Abdelali; Xu, Ziqin; Wang, Zhezhi

    2013-04-01

    Lotus corniculatus L. is used worldwide as a forage crop due to its abundance of secondary metabolites and its ability to grow in severe environments. Although the entire genome of L. corniculatus var. japonicus R. is being sequenced, the differences in morphology and production of secondary metabolites between these two related species have led us to investigate this variability at the genetic level, in particular the differences in flavonoid biosynthesis. Our goal is to use the resulting information to develop more valuable forage crops and medicinal materials. Here, we conducted Illumina/Solexa sequencing to profile the transcriptome of L. corniculatus. We produced 26,492,952 short reads that corresponded to 2.38 gigabytes of total nucleotides. These reads were then assembled into 45,698 unigenes, of which a large number associated with secondary metabolism were annotated. In addition, we identified 2,998 unigenes based on homology with L. japonicus transcription factors (TFs) and grouped them into 55 families. Meanwhile, a comparison of four tag-based digital gene expression libraries, built from the flowers, pods, leaves, and roots, revealed distinct patterns of spatial expression of candidate unigenes in flavonoid biosynthesis. Based on these results, we identified many key enzymes from L. corniculatus which were different from reference genes of L. japonicus, and five TFs that are potential enhancers in flavonoid biosynthesis. Our results provide initial genetics resources that will be valuable in efforts to manipulate the flavonoid metabolic pathway in plants.

  14. De novo transcriptome of safflower and the identification of putative genes for oleosin and the biosynthesis of flavonoids.

    Directory of Open Access Journals (Sweden)

    Haiyan Li

    Full Text Available Safflower (Carthamus tinctorius L. is one of the most extensively used oil crops in the world. However, little is known about how its compounds are synthesized at the genetic level. In this study, Solexa-based deep sequencing on seed, leaf and petal of safflower produced a de novo transcriptome consisting of 153,769 unigenes. We annotated 82,916 of the unigenes with gene annotation and assigned functional terms and specific pathways to a subset of them. Metabolic pathway analysis revealed that 23 unigenes were predicted to be responsible for the biosynthesis of flavonoids and 8 were characterized as seed-specific oleosins. In addition, a large number of differentially expressed unigenes, for example, those annotated as participating in anthocyanin and chalcone synthesis, were predicted to be involved in flavonoid biosynthesis pathways. In conclusion, the de novo transcriptome investigation of the unique transcripts provided candidate gene resources for studying oleosin-coding genes and for investigating genes related to flavonoid biosynthesis and metabolism in safflower.

  15. Evidence for a Saponin Biosynthesis Pathway in the Body Wall of the Commercially Significant Sea Cucumber Holothuria scabra

    Directory of Open Access Journals (Sweden)

    Shahida Akter Mitu

    2017-11-01

    Full Text Available The sea cucumber (phylum Echinodermata body wall is the first line of defense and is well known for its production of secondary metabolites; including vitamins and triterpenoid glycoside saponins that have important ecological functions and potential benefits to human health. The genes involved in the various biosynthetic pathways are unknown. To gain insight into these pathways in an echinoderm, we performed a comparative transcriptome analysis and functional annotation of the body wall and the radial nerve of the sea cucumber Holothuria scabra; to define genes associated with body wall metabolic functioning and secondary metabolite biosynthesis. We show that genes related to signal transduction mechanisms were more highly represented in the H. scabra body wall, including genes encoding enzymes involved in energy production. Eight of the core triterpenoid biosynthesis enzymes were found, however, the identity of the saponin specific biosynthetic pathway enzymes remains unknown. We confirm the body wall release of at least three different triterpenoid saponins using solid phase extraction followed by ultra-high-pressure liquid chromatography-quadrupole time of flight-mass spectrometry. The resource we have established will help to guide future research to explore secondary metabolite biosynthesis in the sea cucumber.

  16. Final Report on Regulation of Guaiacyl and Syringyl Monolignol Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Vincent L. Chiang

    2006-03-09

    The focus of this research is to understand syringyl monolignol biosynthesis that leads to the formation of syringyl lignin, a type of lignin that can be easily removed during biomass conversion. We have achieved the three originally proposed goals for this project. (1) SAD and CAD genes (enzyme catalytic and kinetic properties) and their functional relevance to CAld5H/AldOMT pathway, (2) spatiotemporal expression patterns of Cald5H, AldOMT, SAD and CAD genes, and (3) functions of CAld5H, AldOMT, and SAD genes in vivo using transgenic aspen. Furthermore, we also found that microRNA might be involved in the upstream regulatory network of lignin biosynthesis and wood formation. The achievements are as below. (1) Based on biochemical and molecular studies, we discovered a novel syringyl-specific alcohol dehydrogenase (SAD) involved in monolignol biosynthesis in angiosperm trees. Through CAld5H/OMT/SAD mediation, syringyl monolignol biosynthesis branches out from guaiacyl pathway at coniferaldehyde; (2) The function of CAld5H gene in this syringyl monolignol biosynthesis pathway also was confirmed in vivo in transgenic Populus; (3) The proposed major monolignol biosynthesis pathways were further supported by the involving biochemical functions of CCR based on a detailed kinetic study; (4) Gene promoter activity analysis also supported the cell-type specific expression of SAD and CAD genes in xylem tissue, consistent with the cell-specific locations of SAD and CAD proteins and with the proposed pathways; (5) We have developed a novel small interfering RNA (siRNA)-mediated stable gene-silencing system in transgenic plants; (6) Using the siRNA and P. trichocarpa transformation/regeneration systems we are currently producing transgenic P. trichocarpa to investigate the interactive functions of CAD and SAD in regulating guaiacyl and syringyl lignin biosynthesis; (7) We have cloned for the first time from a tree species, P. trichocarpa, small regulatory RNAs termed micro

  17. Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

    Directory of Open Access Journals (Sweden)

    Franziska Hemmerling

    2016-07-01

    Full Text Available This review highlights the biosynthesis of heterocycles in polyketide natural products with a focus on oxygen and nitrogen-containing heterocycles with ring sizes between 3 and 6 atoms. Heterocycles are abundant structural elements of natural products from all classes and they often contribute significantly to their biological activity. Progress in recent years has led to a much better understanding of their biosynthesis. In this context, plenty of novel enzymology has been discovered, suggesting that these pathways are an attractive target for future studies.

  18. Topical problems in the biosynthesis of red blood pigment

    International Nuclear Information System (INIS)

    Franck, B.

    1982-01-01

    Uroporphyrinogen III plays a key role in the biosynthesis of heme, the red pigment of blood. In vivo studies with specifically 14 C- and 3 H-labeled precursors have revealed that the formation of uroporphyrinogen III in the organism follows several primary and subsidiary pathways. Model experiments on the pattern of biosynthesis have led to simple and effective methods of synthesizing uroporphyrin analogs and have shwon that their production is strongly favored thermodynamically, The biologically important porphyrins thus available permit a mechanistic explanantion of the light-induced dermatoses in porphyria diseases and suggest promising medical applications in diagnosis and therapy. (orig.)

  19. Carbon extension in peptidylnucleoside biosynthesis by radical-SAM enzymes

    Science.gov (United States)

    Lilla, Edward A.; Yokoyama, Kenichi

    2016-01-01

    Nikkomycins and polyoxins are antifungal peptidylnucleoside (PN) antibiotics active against human and plant pathogens. Here, we report that during PN biosynthesis in Streptomyces cacaoi and Streptomyces tendae, the C5′-extension of the nucleoside essential for downstream structural diversification is catalyzed by a conserved radical S-adenosyl-L-methionine (SAM) enzyme, PolH or NikJ. This is distinct from the nucleophilic mechanism reported for antibacterial nucleosides and represents a novel mechanism of nucleoside natural product biosynthesis. PMID:27642865

  20. Phosphoribosyl Diphosphate (PRPP): Biosynthesis, Enzymology, Utilization, and Metabolic Significance

    DEFF Research Database (Denmark)

    Hove-Jensen, Bjarne; Andersen, Kasper R; Kilstrup, Mogens

    2017-01-01

    . PRPP is utilized in the biosynthesis of purine and pyrimidine nucleotides, the amino acids histidine and tryptophan, the cofactors NAD and tetrahydromethanopterin, arabinosyl monophosphodecaprenol, and certain aminoglycoside antibiotics. The participation of PRPP in each of these metabolic pathways...... analysis. PRPP, furthermore, is an effector molecule of purine and pyrimidine nucleotide biosynthesis, either by binding to PurR or PyrR regulatory proteins or as an allosteric activator of carbamoylphosphate synthetase. Genetic analyses have disclosed a number of mutants altered in the PRPP synthase...

  1. [Biosynthesis of benzoisochromanequinones antibiotics from streptomycetes--a review].

    Science.gov (United States)

    Wang, Wei; Wang, Huili; Li, Aiying

    2012-05-04

    Benzoisochromanequinones antibiotics, a group of bioactive polyketide compounds with aromatic polyketide skeletal cores, are accumulated in streptomycetes. The biosynthesis of benzoisochromanequinones antibiotics has triggered great interest because they not only represent model biosynthetic mechanisms of aromatic polyketide skeletal structures, but also possess a variety of tailoring modifications rendering them highly structural and bioactive diversity. Here we reviewed important advances in biosynthesis of benzoisochromanequinones antibiotics in recent 25 years with focusing on the modification mechanisms of these compounds and on the prospects of the metabolic engineering and pharmaceutical discovery of benzoisochromanequinones antibiotics.

  2. Structure, Biosynthesis, and Occurrence of Bacterial Pyrrolizidine Alkaloids.

    Science.gov (United States)

    Schimming, Olivia; Challinor, Victoria L; Tobias, Nicholas J; Adihou, Hélène; Grün, Peter; Pöschel, Laura; Richter, Christian; Schwalbe, Harald; Bode, Helge B

    2015-10-19

    Pyrrolizidine alkaloids (PAs) are widespread plant natural products with potent toxicity and bioactivity. Herein, the identification of bacterial PAs from entomopathogenic bacteria using differential analysis by 2D NMR spectroscopy (DANS) and mass spectrometry is described. Their biosynthesis was elucidated to involve a non-ribosomal peptide synthetase. The occurrence of these biosynthesis gene clusters in Gram-negative and Gram-positive bacteria indicates an important biological function in bacteria. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Automotive electronics design fundamentals

    CERN Document Server

    Zaman, Najamuz

    2015-01-01

    This book explains the topology behind automotive electronics architectures and examines how they can be profoundly augmented with embedded controllers. These controllers serve as the core building blocks of today’s vehicle electronics. Rather than simply teaching electrical basics, this unique resource focuses on the fundamental concepts of vehicle electronics architecture, and details the wide variety of Electronic Control Modules (ECMs) that enable the increasingly sophisticated "bells & whistles" of modern designs.  A must-have for automotive design engineers, technicians working in automotive electronics repair centers and students taking automotive electronics courses, this guide bridges the gap between academic instruction and industry practice with clear, concise advice on how to design and optimize automotive electronics with embedded controllers.

  4. Internet and Electronic Information Management

    Science.gov (United States)

    2004-12-01

    centers to form consortia and share electronic information sources. Although traditional resource sharing arrangements encouraged competition rather... electronic information sources are a challenge for electronic information managers. Libraries and information centers are no longer “the only game in town...

  5. Electronics Environmental Benefits Calculator

    Science.gov (United States)

    The Electronics Environmental Benefits Calculator (EEBC) was developed to assist organizations in estimating the environmental benefits of greening their purchase, use and disposal of electronics.The EEBC estimates the environmental and economic benefits of: Purchasing Electronic Product Environmental Assessment Tool (EPEAT)-registered products; Enabling power management features on computers and monitors above default percentages; Extending the life of equipment beyond baseline values; Reusing computers, monitors and cell phones; and Recycling computers, monitors, cell phones and loads of mixed electronic products.The EEBC may be downloaded as a Microsoft Excel spreadsheet.See https://www.federalelectronicschallenge.net/resources/bencalc.htm for more details.

  6. Systems Level Engineering of Plant Cell Wall Biosynthesis to Improve Biofuel Feedstock Quality

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, Samuel

    2013-09-27

    Our new regulatory model of cell wall biosynthesis proposes original network architecture with several newly incorporated components. The mapped set of protein-DNA interactions will serve as a foundation for 1) understanding the regulation of a complex and integral plant component and 2) the manipulation of crop species for biofuel and biotechnology purposes. This study revealed interesting and novel aspects of grass growth and development and further enforce the importance of a grass model system. By functionally characterizing a suite of genes, we have begun to improve the sparse model for transcription regulation of biomass accumulation in grasses. In the process, we have advanced methodology and brachy molecular genetic tools that will serve as valuable community resource.

  7. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    The global electrical energy consumption is still rising and there is an urgent demand to increase the power capacity. It is expected that the power capacity has to be doubled within 20 years. The production, distribution and use of energy should be as efficient as possible and incentives to save...... energy at the end-user should also be set up. Deregulation of energy has in the past lowered the investment in larger power plants, which means the need for new electrical power sources will be high in the near future. Two major technologies will play important roles to solve the future problems. One...... is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...

  8. Comprehensive assessment of the genes involved in withanolide biosynthesis from Withania somnifera: chemotype-specific and elicitor-responsive expression.

    Science.gov (United States)

    Agarwal, Aditya Vikram; Gupta, Parul; Singh, Deeksha; Dhar, Yogeshwar Vikram; Chandra, Deepak; Trivedi, Prabodh Kumar

    2017-07-01

    Withania somnifera (L.) Dunal (Family, Solanaceae), is among the most valuable medicinal plants used in Ayurveda owing to its rich reservoir of pharmaceutically active secondary metabolites known as withanolides. Withanolides are C 28 -steroidal lactones having a triterpenoidal metabolic origin synthesised via mevalonate (MVA) pathway and methyl-D-erythritol-4-phosphate (MEP) pathway involving metabolic intermediacy of 24-methylene (C 30 -terpenoid) cholesterol. Phytochemical studies suggest differences in the content and/or nature of withanolides in different tissues of different chemotypes. Though development of genomic resources has provided information about putative genes encoding enzymes for biosynthesis of intermediate steps of terpenoid backbone, not much is known about their regulation and response to elicitation. In this study, we generated detailed molecular information about genes catalysing key regulatory steps of withanolide biosynthetic pathway. The full-length sequences of genes encoding enzymes for intermediate steps of terpenoid backbone biosynthesis and their paralogs have been characterized for their functional and structural properties as well as phylogeny using bioinformatics approach. The expression analysis suggests that these genes are differentially expressed in different tissues (with maximal expression in young leaf), chemotypes and in response to salicylic acid (SA) and methyl jasmonate (MJ) treatments. Sub-cellular localization studies suggest that both paralogs of sterol ∆-7 reductase (WsDWF5-1 and WsDWF5-2) are localized in the endoplasmic reticulum (ER) thus supporting their indispensible role in withanolide biosynthesis. Comprehensive information developed, in this study, will lead to elucidation of chemotype- as well as tissue-specific withanolide biosynthesis and development of new tools for functional genomics in this important medicinal plant.

  9. Differential Antioxidant Responses and Perturbed Porphyrin Biosynthesis after Exposure to Oxyfluorfen and Methyl Viologen in Oryza sativa.

    Science.gov (United States)

    Pham, Nhi-Thi; Kim, Jin-Gil; Jung, Sunyo

    2015-07-21

    We compared antioxidant responses and regulation of porphyrin metabolism in rice plants treated with oxyfluorfen (OF) or methyl viologen (MV). Plants treated with MV exhibited not only greater increases in conductivity and malondialdehyde but also a greater decline in Fv/Fm, compared to plants treated with OF. MV-treated plants had greater increases in activities of superoxide dismutase (SOD) and catalase (CAT) as well as transcript levels of SODA and CATA than OF-treated plants after 28 h of the treatments, whereas increases in ascorbate peroxidase (APX) activity and transcript levels of APXA and APXB were greater in OF-treated plants. Both OF- and MV-treated plants resulted in not only down-regulation of most genes involved in porphyrin biosynthesis but also disappearance of Mg-porphyrins during the late stage of photooxidative stress. By contrast, up-regulation of heme oxygenase 2 (HO2) is possibly part of an efficient antioxidant response to compensate photooxidative damage in both treatments. Our data show that down-regulated biosynthesis and degradation dynamics of porphyrin intermediates have important roles in photoprotection of plants from perturbed porphyrin biosynthesis and photosynthetic electron transport. This study suggests that porphyrin scavenging as well as strong antioxidative activities are required for mitigating reactive oxygen species (ROS) production under photooxidative stress caused by OF and MV.

  10. Optimization of silver nanoparticles biosynthesis mediated by Aspergillus niger NRC1731 through application of statistical methods: enhancement and characterization.

    Science.gov (United States)

    Elsayed, Maysa A; Othman, Abdelmageed M; Hassan, Mohamed M; Elshafei, Ali M

    2018-03-01

    The fungal-mediated silver nanoparticles (AgNPs) biosynthesis optimization via the application of central composite design (CCD) response surface to develop an effective ecofriendly and inexpensive green process was the aim of the current study. Nanosilver biosynthesis using the Aspergillus niger NRC1731 cell-free filtrate (CFF) was studied through involving the most parameters affecting the AgNPs green synthesis and its interactions effects. The statistical optimization models showed that using 59.37% of CFF in reaction containing 1.82 mM silver nitrate for 34 h at pH 7.0 is the optimum value to optimize the AgNPs biosynthesis. The obtained AgNPs were characterized by means of electron microscopy, UV/visible spectrophotometry, energy dispersive X-ray analysis and infrared spectroscopy to elucidate its almost spherical shape with diameter of 3-20 nm. The produced AgNPs exhibited a considerable antimicrobial activity against Bacillus mycoides , Escherichia coli in addition to Candida albicans .

  11. Leaf spot disease adversely affects human health-promoting constituents and withanolide biosynthesis in Withania somnifera (L.) Dunal.

    Science.gov (United States)

    Singh, V; Singh, B; Sharma, A; Kaur, K; Gupta, A P; Salar, R K; Hallan, V; Pati, P K

    2017-01-01

    The present work investigates the implication of leaf spot disease on the antioxidant potential and commercial value of pharmaceutically important constituents of Withania somnifera, a high-valued medicinal plant. Leaf spot disease was induced in W. somnifera by inoculating Alternaria alternata (Fr.) Keiss. pathogen. Total polyphenolic content and antioxidant potential showed a significant decrease during leaf spot disease. Evaluation of pharmaceutically active constituents withaferin A, withanone and withanolide A utilizing high-performance liquid chromatography showed a significant decrease in diseased samples as compared to healthy ones. Quantitative expression of major genes involved in withanolide biosynthesis also showed down-regulation in diseased samples. Alterations in the ultra-structure of chloroplasts were also analysed under transmission electron microscopy to get a better insight into the changes of withanolide biosynthesis in leaf during disease infestation. The present work suggests that when the pathogenic fungus invades the host plants, it evokes multiple responses, which could be studied at various levels. The knowledge gained from this work will provide appropriate rationale for controlling the bio-deterioration of the pharmaceutically active metabolites in W. somnifera and development of suitable strategies against leaf spot disease. This is the first study to investigate the effect of leaf spot disease on the human health-promoting constituents and withanolide biosynthesis in this high-valued medicinal plant. © 2016 The Society for Applied Microbiology.

  12. Differential Antioxidant Responses and Perturbed Porphyrin Biosynthesis after Exposure to Oxyfluorfen and Methyl Viologen in Oryza sativa

    Directory of Open Access Journals (Sweden)

    Nhi-Thi Pham

    2015-07-01

    Full Text Available We compared antioxidant responses and regulation of porphyrin metabolism in rice plants treated with oxyfluorfen (OF or methyl viologen (MV. Plants treated with MV exhibited not only greater increases in conductivity and malondialdehyde but also a greater decline in Fv/Fm, compared to plants treated with OF. MV-treated plants had greater increases in activities of superoxide dismutase (SOD and catalase (CAT as well as transcript levels of SODA and CATA than OF-treated plants after 28 h of the treatments, whereas increases in ascorbate peroxidase (APX activity and transcript levels of APXA and APXB were greater in OF-treated plants. Both OF- and MV-treated plants resulted in not only down-regulation of most genes involved in porphyrin biosynthesis but also disappearance of Mg-porphyrins during the late stage of photooxidative stress. By contrast, up-regulation of heme oxygenase 2 (HO2 is possibly part of an efficient antioxidant response to compensate photooxidative damage in both treatments. Our data show that down-regulated biosynthesis and degradation dynamics of porphyrin intermediates have important roles in photoprotection of plants from perturbed porphyrin biosynthesis and photosynthetic electron transport. This study suggests that porphyrin scavenging as well as strong antioxidative activities are required for mitigating reactive oxygen species (ROS production under photooxidative stress caused by OF and MV.

  13. Biosynthesis of allene oxides in Physcomitrella patens

    Directory of Open Access Journals (Sweden)

    Scholz Julia

    2012-11-01

    Full Text Available Abstract Background The moss Physcomitrella patens contains C18- as well as C20-polyunsaturated fatty acids that can be metabolized by different enzymes to form oxylipins such as the cyclopentenone cis(+-12-oxo phytodienoic acid. Mutants defective in the biosynthesis of cyclopentenones showed reduced fertility, aberrant sporophyte morphology and interrupted sporogenesis. The initial step in this biosynthetic route is the conversion of a fatty acid hydroperoxide to an allene oxide. This reaction is catalyzed by allene oxide synthase (AOS belonging as hydroperoxide lyase (HPL to the cytochrome P450 family Cyp74. In this study we characterized two AOS from P. patens, PpAOS1 and PpAOS2. Results Our results show that PpAOS1 is highly active with both C18 and C20-hydroperoxy-fatty acid substrates, whereas PpAOS2 is fully active only with C20-substrates, exhibiting trace activity (~1000-fold lower kcat/KM with C18 substrates. Analysis of products of PpAOS1 and PpHPL further demonstrated that both enzymes have an inherent side activity mirroring the close inter-connection of AOS and HPL catalysis. By employing site directed mutagenesis we provide evidence that single amino acid residues in the active site are also determining the catalytic activity of a 9-/13-AOS – a finding that previously has only been reported for substrate specific 13-AOS. However, PpHPL cannot be converted into an AOS by exchanging the same determinant. Localization studies using YFP-labeled AOS showed that PpAOS2 is localized in the plastid while PpAOS1 may be found in the cytosol. Analysis of the wound-induced cis(+-12-oxo phytodienoic acid accumulation in PpAOS1 and PpAOS2 single knock-out mutants showed that disruption of PpAOS1, in contrast to PpAOS2, results in a significantly decreased cis(+-12-oxo phytodienoic acid formation. However, the knock-out mutants of neither PpAOS1 nor PpAOS2 showed reduced fertility, aberrant sporophyte morphology or interrupted sporogenesis

  14. Bio-synthesis of gold nanoparticles by human epithelial cells, in vivo

    International Nuclear Information System (INIS)

    Larios-Rodriguez, E; Rangel-Ayon, C; Herrera-Urbina, R; Castillo, S J; Zavala, G

    2011-01-01

    Healthy epithelial cells, in vivo, have the ability to synthesize gold nanoparticles when aqueous tetrachloroauric acid is made to react with human skin. Neither a reducing agent nor a protecting chemical is needed for this bio-synthesis method. The first indication of gold nanoparticle formation is the staining of the skin, which turns deep purple. Stereoscopic optical micrographs of human skin tissue in contact with aqueous tetrachloroauric acid clearly show the staining of the epithelial cells. The UV-Vis spectrum of these epithelial cells shows an absorption band with a maximum at 553 nm. This absorption peak is within the wavelength region where the surface plasmon resonance (SPR) band of aqueous colloidal gold exhibits a maximum. Transmission electron micrographs show that gold nanoparticles synthesized by epithelial cells have sizes between 1 and 100 nm. The electron diffraction pattern of these nanoparticles reveals a crystalline structure whose interplanar distances correspond to fcc metallic gold. Transmission electron micrographs of ultra-thin (70 nm thick) slices of epithelial cells clearly and undoubtedly demonstrate that gold nanoparticles are inside the cell. According to high resolution transmission electron micrographs of intracellular single gold nanoparticles, they have the shape of a polyhedron.

  15. Marine Nucleosides: Structure, Bioactivity, Synthesis and Biosynthesis

    Directory of Open Access Journals (Sweden)

    Ri-Ming Huang

    2014-12-01

    Full Text Available Nucleosides are glycosylamines that structurally form part of nucleotide molecules, the building block of DNA and RNA. Both nucleosides and nucleotides are vital components of all living cells and involved in several key biological processes. Some of these nucleosides have been obtained from a variety of marine resources. Because of the biological importance of these compounds, this review covers 68 marine originated nucleosides and their synthetic analogs published up to June 2014. The review will focus on the structures, bioactivities, synthesis and biosynthetic processes of these compounds.

  16. 大學圖書館電子資源之需求分析與行銷策略之研究 A Study of Demands Analysis and Marketing Strategy of Electronic Resources in University Library

    OpenAIRE

    Huang-Yu Liu; Jung-Huei Shu

    2008-01-01

    電子資源的出現,使得知識載體有了新的突破,提高了使用者的便利性與即時性。對於圖書館而言,如何使電子資源的使用效益達到最高,必須思考一套有效的行銷策略。電子資源行銷概念應以讀者為導向,尊重讀者的資訊需求,並利用各種宣傳技巧,行銷電子資源,使圖書館能提供更完善的服務。本研究之目的旨在探討讀者的使用需求及電子資源的推廣策略,以獲致最有效益的行銷方式。研究對象以開南大學日間部四學院(商學院、運輸觀光學院、資訊學院、人文社會學院)學生為樣本,佐以缺口分析模型為分析架構,藉以找出個案中讀者/學生對於電子資源使用的真實需求,並進而歸納出提供服務的大學圖書館在其推廣或行銷服務上可有的因應策略。The emergence of electronic resources has made new breakthrough in knowledge carriers because of their ease of use, instant availability, and the characteristic of no time and space constraints. For public...

  17. In situ biosynthesis of bacterial nanocellulose-CaCO{sub 3} hybrid bionanocomposite: One-step process

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadkazemi, Faranak, E-mail: f_mkazemi@sbu.ac.ir [Department of Cellulose and Paper Technology, Faculty of New Technologies Engineering, Shahid Beheshti University, Science and Research Campus, Zirab, Savadkooh, Mazandaran (Iran, Islamic Republic of); Faria, Marisa; Cordeiro, Nereida [Faculty of Exact Science and Engineering, University of Madeira, Funchal (Portugal)

    2016-08-01

    In this work, a simple and green route to the synthesis of the bacterial nanocellulose-calcium carbonate (BNC/CaCO{sub 3}) hybrid bionanocomposites using one-step in situ biosynthesis was studied. The CaCO{sub 3} was incorporated in the bacterial nanocellulose structure during the cellulose biosynthesis by Gluconacetobacter xylinus PTCC 1734 bacteria. Hestrin-Schramm (HS) and Zhou (Z) culture media were used to the hybrid bionanocomposites production and the effect of ethanol addition was investigated. Attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, inverse gas chromatography and thermogravimetric analysis were used to characterize the samples. The experimental results demonstrated that the ethanol and culture medium play an important role in the BNC/CaCO{sub 3} hybrid bionanocomposites production, structure and properties. The BNC/CaCO{sub 3} biosynthesized in Z culture medium revealed higher O/C ratio and amphoteric surface character, which justify the highest CaCO{sub 3} content incorporation. The CaCO{sub 3} was incorporated into the cellulosic matrix decreasing the bacterial nanocellulose crystallinity. This work reveals the high potential of in situ biosynthesis of BNC/CaCO{sub 3} hybrid bionanocomposites and opens a new way to the high value-added applications of bacterial nanocellulose. - Graphical Abstract: Display Omitted - Highlights: • BNC/CaCO{sub 3} hybrid bionanocomposites were produced using in situ biosynthesis process. • Ethanol and culture medium play an important role in the production and properties. • Z-BNC/CaCO{sub 3} bionanocomposites revealed higher O/C ratio and amphoteric surface character. • CaCO{sub 3} incorporated into the BNC decreased crystallinity.

  18. [Advances and prospects of taxol biosynthesis by endophytic fungi].

    Science.gov (United States)

    Zhao, Kai; Yu, Lu; Jin, Yuyan; Ma, Xueling; Liu, Dan; Wang, Xiaohua; Wang, Xin

    2016-08-25

    Taxol is one of the most important chemotherapeutic drugs against cancer. Taxol has been mainly extracted from the bark of yews for a long time. However, methods for the extraction of taxol from the bark of Taxus species were inefficient and environmentally costly. As a result of the high ecological toll exacted on trees with the potential for Pacific yew extinction, investigators began to look for other methods of taxol production. Recently, increasing efforts have been made to develop alternative means of taxol production, such as using complete chemical synthesis, semi-synthesis, Taxus spp. plant cell culture and microbe fermentation. Using microbe fermentation in the production of taxol would be a very prospective method for obtaining a large amount of taxol. Therefore, it is necessary to understand the molecular basis and genetic regulation mechanisms of taxol biosynthesis by endophytic fungi, which may be helpful to construct the genetic engineering strain with high taxol output. In this paper, the taxol biosynthesis pathway from Taxus cells and the advantages of taxol biosynthesis by endophytic fungi were discussed. The study on the isolation and biodiversity of taxol-producing endophytic fungi and the taxol biosynthesis related genes are also discussed.

  19. Regulation of Isoprenoid Pheromone Biosynthesis in Bumblebee Males

    Czech Academy of Sciences Publication Activity Database

    Prchalová, Darina; Buček, Aleš; Brabcová, Jana; Žáček, Petr; Kindl, Jiří; Valterová, Irena; Pichová, Iva

    2016-01-01

    Roč. 17, č. 3 (2016), s. 260-267 ISSN 1439-4227 R&D Projects: GA MŠk LO1302; GA ČR GA15-06569S Institutional support: RVO:61388963 Keywords : biosynthesis * Bombus spp. * gene expression * isoprenoids * pheromones * transcriptional regulation Subject RIV: CE - Biochemistry Impact factor: 2.847, year: 2016

  20. Biosynthesis of the red antibiotic, prodigiosin, in Serratia

    DEFF Research Database (Denmark)

    Williamson, Neil R; Simonsen, Henrik Toft; Ahmed, Raef A A

    2005-01-01

    from Serratia sp. ATCC 39006. The biosynthetic intermediates accumulating in each mutant have been analysed by LC-MS, cross-feeding and genetic complementation studies. Based on these results we assign specific roles in the biosynthesis of MBC to the following Pig proteins: PigI, PigG, PigA, PigJ, Pig...

  1. Biosynthesis of lipophilic compounds in tomato fruit | Angaman ...

    African Journals Online (AJOL)

    A study performed with chromoplasts to know the origin of the precursors for carotenoids biosynthesis using a variety of 14C-labelled precursors showed that the most important incorporation was found in lipids. This study aims to understand the biochemical and metabolic processes operating during tomato fruit ripening.

  2. Temporal expression of genes involved in the biosynthesis of ...

    African Journals Online (AJOL)

    Jane

    2011-10-10

    Oct 10, 2011 ... Gibberellins (GAs) are a large family of endogenous plant growth regulators. Bioactive GAs influence nearly all processes during plant growth and development. In the present study, we cloned and identified 10 unique genes that are potentially involved in the biosynthesis of GAs, including one. BpGGDP ...

  3. Biosynthesis of silver nanoparticles and its antibacterial activity ...

    African Journals Online (AJOL)

    In the present research work, biosynthesis of silver nanoparticles and its activity on bacterial pathogens were investigated. Silver nanoparticles were rapidly synthesized using Urospora sp. and the formation of nanoparticles was observed within 30 min. The results recorded from UV–vis spectrum, Fourier Transform Infrared ...

  4. The magnesium chelation step in chlorophyll biosynthesis. Progress report 1993

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, J.D.

    1993-12-31

    Progress is reported on the identification and fractionation of Magnesium chealatase, an enzyme involved in addition of Mg to chlorophyll during the later`s biosynthesis. Progress is documented as a series of synopsis of published and unpublished papers by the author.

  5. Molecular and biochemical studies of fragrance biosynthesis in rose

    NARCIS (Netherlands)

    Sun, P.

    2017-01-01

    Roses are one of the most popular ornamental plants, whose floral volatiles are not only involved in environmental interactions but also widely used by industries. The biosynthesis of many of these volatiles in roses is not well understood. This thesis describes alternative pathways for the

  6. Biosynthesis of polyketides by trans-AT polyketide synthases.

    OpenAIRE

    Helfrich Eric J N; Piel Jörn

    2016-01-01

    This review discusses the biosynthesis of natural products that are generated by trans AT polyketide synthases a family of catalytically versatile enzymes that represents one of the major group of proteins involved in the production of bioactive polyketides. The article includes 609 references and covers the literature from 2009 through June 2015.

  7. Biosynthesis of polyketides by trans-AT polyketide synthases.

    Science.gov (United States)

    Helfrich, Eric J N; Piel, Jörn

    2016-02-01

    This review discusses the biosynthesis of natural products that are generated by trans-AT polyketide synthases, a family of catalytically versatile enzymes that represents one of the major group of proteins involved in the production of bioactive polyketides. The article includes 609 references and covers the literature from 2009 through June 2015.

  8. Biosynthesis of cellulolytic enzymes by Tricothecium roseum with ...

    African Journals Online (AJOL)

    Among various soluble carbon and complex nitrogen sources tested in this study, carboxymethylcellulose and peptone supported maximum production of both cellulolytic enzymes. Under all suitable growth conditions, the enzyme biosynthesis was remarkably increased when the inducer citric acid was added to the PDYE ...

  9. Anthocyanin biosynthesis in fruit tree crops: Genes and their regulation

    African Journals Online (AJOL)

    The anthocyanin biosynthesis pathway is a little complex with branches responsible for the synthesis of a variety of metabolites. In fruit tree crops, during the past decade, many structural genes encoding enzymes in the anthocyanin biosynthetic pathway and various regulatory genes encoding transcription factors that ...

  10. Temporal expression of genes involved in the biosynthesis of ...

    African Journals Online (AJOL)

    Gibberellins (GAs) are a large family of endogenous plant growth regulators. Bioactive GAs influence nearly all processes during plant growth and development. In the present study, we cloned and identified 10 unique genes that are potentially involved in the biosynthesis of GAs, including one BpGGDP gene, two BpCPS ...

  11. Expression profiles of genes involved in tanshinone biosynthesis of ...

    Indian Academy of Sciences (India)

    Expression profiles of genes involved in tanshinone biosynthesis of two. Salvia miltiorrhiza genotypes with different tanshinone contents. Zhenqiao Song, Jianhua Wang and Xingfeng Li. J. Genet. 95, 433–439. Table 1. S. miltiorrhiza genes and primer pairs used for qRT-PCR. Gene. GenBank accession. Primer name.

  12. Biosynthesis of silver nanoparticles by Leishmania tropica | Rahi ...

    African Journals Online (AJOL)

    A novel biosynthesis route for Silver Nanoparticles (Ag-NPs) was attempted in the present study using Leishmania tropica the causative agent of cutaneous leishmaniasis in different countries, particularly in Mediterranean region in Iraq. Silver nanoparticles were successfully synthesized from AgNO3 by reduction of ...

  13. Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species

    Directory of Open Access Journals (Sweden)

    Kamiar Zomorodian

    2016-01-01

    Full Text Available Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM. There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity.

  14. Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species

    Science.gov (United States)

    Pourshahid, Seyedmohammad; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

    2016-01-01

    Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM). There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity. PMID:27652264

  15. Hacking an Algal Transcription Factor for Lipid Biosynthesis.

    Science.gov (United States)

    Chen, Xiulai; Hu, Guipeng; Liu, Liming

    2018-03-01

    Transcriptional engineering is a viable means for engineering microalgae to produce lipid, but it often results in a trade-off between production and growth. A recent study shows that engineering a single transcriptional regulator enables efficient carbon partitioning to lipid biosynthesis with high biomass productivity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Arogenate Dehydratase Isoforms Differentially Regulate Anthocyanin Biosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Chen, Qingbo; Man, Cong; Li, Danning; Tan, Huijuan; Xie, Ye; Huang, Jirong

    2016-12-05

    Anthocyanins, a group of L-phenylalanine (Phe)-derived flavonoids, have been demonstrated to play important roles in plant stress resistance and interactions between plants and insects. Although the anthocyanin biosynthetic pathway and its regulatory mechanisms have been extensively studied, it remains unclear whether the level of Phe supply affects anthocyanin biosynthesis. Here, we investigated the roles of arogenate dehydratases (ADTs), the key enzymes that catalyze the conversion of arogenate into Phe, in sucrose-induced anthocyanin biosynthesis in Arabidopsis. Genetic analysis showed that all six ADT isoforms function redundantly in anthocyanin biosynthesis but have differential contributions. ADT2 contributes the most to anthocyanin accumulation, followed by ADT1 and ADT3, and ADT4-ADT6. We found that anthocyanin content is positively correlated with the levels of Phe and sucrose-induced ADT transcripts in seedlings. Consistently, addition of Phe to the medium could dramatically increase anthocyanin content in the wild-type plants and rescue the phenotype of the adt1 adt3 double mutant regarding the anthocyanin accumulation. Moreover, transgenic plants overexpressing ADT4, which appears to be less sensitive to Phe than overexpression of ADT2, hyperaccumulate Phe and produce elevated level of anthocyanins. Taken together, our results suggest that the level of Phe is an important regulatory factor for sustaining anthocyanin biosynthesis. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

  17. The pyrroloquinoline quinone biosynthesis pathway revisited: A structural approach

    Directory of Open Access Journals (Sweden)

    Schwarzenbacher Robert

    2008-03-01

    Full Text Available Abstract Background The biosynthesis pathway of Pyrroloquinoline quinone, a bacterial redox active cofactor for numerous alcohol and aldose dehydrogenases, is largely unknown, but it is proven that at least six genes in Klebsiella pneumoniae (PqqA-F are required, all of which are located in the PQQ-operon. Results New structural data of some PQQ biosynthesis proteins and their homologues provide new insights and functional assignments of the proteins in the pathway. Based on sequence analysis and homology models we propose the role and catalytic function for each enzyme involved in this intriguing biosynthesis pathway. Conclusion PQQ is derived from the two amino acids glutamate and tyrosine encoded in the precursor peptide PqqA. Five reactions are necessary to form this quinone cofactor. The PqqA peptide is recognised by PqqE, which links the C9 and C9a, afterwards it is accepted by PqqF which cuts out the linked amino acids. The next reaction (Schiff base is spontaneous, the following dioxygenation is catalysed by an unknown enzyme. The last cyclization and oxidation steps are catalysed by PqqC. Taken together the known facts of the different proteins we assign a putative function to all six proteins in PQQ biosynthesis pathway.

  18. Lincosamides: Chemical structure, biosynthesis, mechanism of action, resistance, and applications

    Czech Academy of Sciences Publication Activity Database

    Spížek, Jaroslav; Řezanka, Tomáš

    2017-01-01

    Roč. 133, June 1 SI (2017), s. 20-28 ISSN 0006-2952 Institutional support: RVO:61388971 Keywords : Lincosamides * Chemical structure * Biosynthesis and mechanism of action Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.581, year: 2016

  19. Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species.

    Science.gov (United States)

    Zomorodian, Kamiar; Pourshahid, Seyedmohammad; Sadatsharifi, Arman; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

    2016-01-01

    Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM). There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity.

  20. Stimulation of reserpine biosynthesis in the callus of Rauvolfia ...

    African Journals Online (AJOL)

    So enhancing this alkaloid in the already available system is a beneficial approach. Tryptophan is the starting material in the biosynthesis of reserpine. Callus was induced from leaf explants of Rauvolfia tetraphylla L. on MS medium supplemented with the combination of 9 μM 2,4-D and 25, 50, 75 and 100 mg/l tryptophan.

  1. Rapid biosynthesis and characterization of silver nanoparticles: an assessment of antibacterial and antimycotic activity

    Science.gov (United States)

    Kanawaria, Sajjan Kumar; Sankhla, Aryan; Jatav, Pradeep Kumar; Yadav, Raghvendra Singh; Verma, Kumar Sambhav; Velraj, Parthiban; Kachhwaha, Sumita; Kothari, Shanker Lal

    2018-04-01

    Bioassisted synthesis provides a facile, convenient, and promising approach to produce many inorganic nanostructures. Herein, we report a rapid biosynthesis of silver nanoparticles (AgNPs) using Thuja occidentalis (L.) leaf extract with an emphasis on their antibacterial and antimycotic activity. Interestingly, the synthesis of AgNPs was completed in a short duration of 35-40 min. The electron micrographs showed AgNPs with particles 15 mm. The antimycotic activity against Aspergillus niger, Fusarium spp., and Alternaria alternata species increased monotonically with nanoparticle concentration in the growth media. A 10 ppm solution of AgNP was detrimental to fungal growth. Thus, the technique provides an avenue to synthesize antibiotic AgNPs without use of other external agents.

  2. Biosynthesis and characterization of gold nanoparticles using extracts of tamarindus indica L leaves

    International Nuclear Information System (INIS)

    Correa, S N; Naranjo, A M; Herrera, A P

    2016-01-01

    This study reports the biosynthesis of gold nanoparticles using an extract of Tamarindus indica L. leaves. Phenols, ketones and carboxyls were present in the leaves of T. indica. These organic compounds that allowed the synthesis of nanoparticles were identified by gas chromatography coupled to mass spectrometry (GC/MS) and High Pressure Liquid Chromatographic (HPLC). Synthesis of gold nanoparticles was performed with the extract of T. indica leaves and an Au +3 aqueous solutions (HAuCl 4 ) at room temperature with one hour of reaction time. Characterization of gold nanoparticles was performed by UV visible spectroscopy, scanning electron microscopy (SEM) and EDX. The results indicated the formation of gold nanoparticles with a wavelength of 576nm and an average size of 52±5nm. The EDX technique confirmed the presence of gold nanoparticles with 12.88% in solution. (paper)

  3. Genus-wide physicochemical evidence of extracellular crystalline silver nanoparticles biosynthesis by Morganella spp.

    Directory of Open Access Journals (Sweden)

    Rasesh Y Parikh

    Full Text Available This study was performed to determine whether extracellular silver nanoparticles (AgNPs production is a genus-wide phenotype associated with all the members of genus Morganella, or only Morganella morganii RP-42 isolate is able to synthesize extracellular Ag nanoparticles. To undertake this study, all the available Morganella isolates were exposed to Ag+ ions, and the obtained nanoproducts were thoroughly analyzed using physico-chemical characterization tools such as transmission electron microscopy (TEM, UV-visible spectrophotometry (UV-vis, and X-ray diffraction (XRD analysis. It was identified that extracellular biosynthesis of crystalline silver nanoparticles is a unique biochemical character of all the members of genus Morganella, which was found independent of environmental changes. Significantly, the inability of other closely related members of the family Enterobacteriaceae towards AgNPs synthesis strongly suggests that AgNPs synthesis in the presence of Ag+ ions is a phenotypic character that is uniquely associated with genus Morganella.

  4. Biosynthesis and characterization of gold nanoparticles using extracts of tamarindus indica L leaves

    Science.gov (United States)

    Correa, S. N.; Naranjo, A. M.; Herrera, A. P.

    2016-02-01

    This study reports the biosynthesis of gold nanoparticles using an extract of Tamarindus indica L. leaves. Phenols, ketones and carboxyls were present in the leaves of T. indica. These organic compounds that allowed the synthesis of nanoparticles were identified by gas chromatography coupled to mass spectrometry (GC/MS) and High Pressure Liquid Chromatographic (HPLC). Synthesis of gold nanoparticles was performed with the extract of T. indica leaves and an Au+3 aqueous solutions (HAuCl4) at room temperature with one hour of reaction time. Characterization of gold nanoparticles was performed by UV visible spectroscopy, scanning electron microscopy (SEM) and EDX. The results indicated the formation of gold nanoparticles with a wavelength of 576nm and an average size of 52±5nm. The EDX technique confirmed the presence of gold nanoparticles with 12.88% in solution.

  5. Treatment with Antibiotics that Interfere with Peptidoglycan Biosynthesis Inhibits Chloroplast Division in the Desmid Closterium

    Science.gov (United States)

    Matsumoto, Hiroko; Takechi, Katsuaki; Sato, Hiroshi; Takio, Susumu; Takano, Hiroyoshi

    2012-01-01

    Charophytes is a green algal group closely related to land plants. We investigated the effects of antibiotics that interfere with peptidoglycan biosynthesis on chloroplast division in the desmid Closterium peracerosum–strigosum–littorale complex. To detect cells just after division, we used colchicine, which inhibits Closterium cell elongation after division. Although normal Closterium cells had two chloroplasts before and after cell division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only one chloroplast after cell division, suggesting that the cells divided without chloroplast division. The antibiotics bacitracin and vancomycin showed no obvious effect. Electron microscopic observation showed that irregular-shaped chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic treatments resulted in the appearance of long cells with irregular chloroplasts and cell death, we counted cell types in the culture. The results suggested that cells with one chloroplast appeared first and then a huge chloroplast was generated that inhibited cell division, causing elongation followed by cell death. PMID:22815801

  6. Novel use of Tat components to increase metabolic flux in light-driven biosynthesis

    DEFF Research Database (Denmark)

    Henriques de Jesus, Maria Perestrello Ramos

    Oxygenic photosynthesis provides plants, algae and cyanobacteria the ability to convert solar energy and CO2 into complex organic molecules. Thus tapping into photosynthesis for synthetic biology efforts has a huge potential for the industrial production of fuels and high value bioactive compounds...... relocating a biosynthetic pathway into the chloroplast, as well as possible solutions. Paper I compares the potential of chloroplasts and cyanobacteria as sustainable biosynthetic compartments and hosts for metabolic engineering. An estimation of the percentage of photosynthetic electrons that can...... be redirected into the biosynthesis of products is given. The availability of photosynthetic reducing power appears to be non-limiting whereas the redirection of the fixed carbon seems to be main challenge for achieving higher product yields. On paper II a novel strategy where the membrane anchors...

  7. Electronic Cigarettes

    Science.gov (United States)

    ... New FDA Regulations Text Size: A A A Electronic Cigarettes Electronic cigarettes (e-cigarettes) are battery operated products designed to ... more about: The latest news and events about electronic cigarettes on this FDA page Electronic cigarette basics on ...

  8. Resource Economics

    Science.gov (United States)

    Conrad, Jon M.

    2000-01-01

    Resource Economics is a text for students with a background in calculus, intermediate microeconomics, and a familiarity with the spreadsheet software Excel. The book covers basic concepts, shows how to set up spreadsheets to solve dynamic allocation problems, and presents economic models for fisheries, forestry, nonrenewable resources, stock pollutants, option value, and sustainable development. Within the text, numerical examples are posed and solved using Excel's Solver. These problems help make concepts operational, develop economic intuition, and serve as a bridge to the study of real-world problems of resource management. Through these examples and additional exercises at the end of Chapters 1 to 8, students can make dynamic models operational, develop their economic intuition, and learn how to set up spreadsheets for the simulation of optimization of resource and environmental systems. Book is unique in its use of spreadsheet software (Excel) to solve dynamic allocation problems Conrad is co-author of a previous book for the Press on the subject for graduate students Approach is extremely student-friendly; gives students the tools to apply research results to actual environmental issues

  9. Biosynthesis and characterization of layered iron phosphate

    International Nuclear Information System (INIS)

    Zhou Weijia; He Wen; Wang Meiting; Zhang Xudong; Yan Shunpu; Tian Xiuying; Sun Xianan; Han Xiuxiu; Li Peng

    2008-01-01

    Layered iron phosphate with uniform morphology has been synthesized by a precipitation method with yeast cells as a biosurfactant. The yeast cells are used to regulate the nucleation and growth of layered iron phosphate. The uniform layered structure is characterized by small-angle x-ray diffraction (SAXD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses. Fourier transform infrared spectroscopy (FT-IR) is used to analyze the chemical bond linkages in organic–inorganic hybrid iron phosphate. The likely synthetic mechanism of nucleation and oriented growth is discussed. The electrical conductivity of hybrid iron phosphate heat-treated at different temperatures is presented

  10. Electronic technology

    International Nuclear Information System (INIS)

    Kim, Jin Su

    2010-07-01

    This book is composed of five chapters, which introduces electronic technology about understanding of electronic, electronic component, radio, electronic application, communication technology, semiconductor on its basic, free electron and hole, intrinsic semiconductor and semiconductor element, Diode such as PN junction diode, characteristic of junction diode, rectifier circuit and smoothing circuit, transistor on structure of transistor, characteristic of transistor and common emitter circuit, electronic application about electronic equipment, communication technology and education, robot technology and high electronic technology.

  11. YCZ-18 Is a New Brassinosteroid Biosynthesis Inhibitor

    Science.gov (United States)

    Oh, Keimei; Matsumoto, Tadashi; Yamagami, Ayumi; Ogawa, Atushi; Yamada, Kazuhiro; Suzuki, Ryuichiro; Sawada, Takayuki; Fujioka, Shozo; Yoshizawa, Yuko; Nakano, Takeshi

    2015-01-01

    Plant hormone brassinosteroids (BRs) are a group of polyhydroxylated steroids that play critical roles in regulating broad aspects of plant growth and development. The structural diversity of BRs is generated by the action of several groups of P450s. Brassinazole is a specific inhibitor of C-22 hydroxylase (CYP90B1) in BR biosynthesis, and the application use of brassinazole has emerged as an effective way of complementing BR-deficient mutants to elucidate the functions of BRs. In this article, we report a new triazole-type BR biosynthesis inhibitor, YCZ-18. Quantitative analysis the endogenous levels of BRs in Arabidopsis indicated that YCZ-18 significantly decreased the BR contents in plant tissues. Assessment of the binding affinity of YCZ-18to purified recombinant CYP90D1 indicated that YCZ-18 induced a typical type II binding spectrum with a Kd value of approximately 0.79 μM. Analysis of the mechanisms underlying the dwarf phenotype associated with YCZ-18 treatment of Arabidopsis indicated that the chemically induced dwarf phenotype was caused by a failure of cell elongation. Moreover, dissecting the effect of YCZ-18 on the induction or down regulation of genes responsive to BRs indicated that YCZ-18 regulated the expression of genes responsible for BRs deficiency in Arabidopsis. These findings indicate that YCZ-18 is a potent BR biosynthesis inhibitor and has a new target site, C23-hydroxylation in BR biosynthesis. Application of YCZ-18 will be a good starting point for further elucidation of the detailed mechanism of BR biosynthesis and its regulation. PMID:25793645

  12. The Electron

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, George

    1972-01-01

    Electrons are elementary particles of atoms that revolve around and outside the nucleus and have a negative charge. This booklet discusses how electrons relate to electricity, some applications of electrons, electrons as waves, electrons in atoms and solids, the electron microscope, among other things.

  13. Biosynthesis of oligosaccharides and fructans in Agave vera cruz : Part III - Biosynthesis of fructans

    International Nuclear Information System (INIS)

    Satyanarayana, M.N.

    1976-01-01

    Evidence has been obtained for the biosynthesis of 'fructans' in Agave vera cruz. A hydrolase-free enzyme preparation from the stem juice with U- 14 C sucrose as substrate and the native fructan as primer leads to incorporation of 14 C fructose into a polymer like compound. This inference is based on criteria such as the chromatographic mobility of the product and the elution volume from a Sephadex G-25 column. Two optimum pHs 4.9 and 6.1 and optimum temperature 377degC are observed for the reaction. The activity is dependent on primer, enzyme, substrate concentration and duration of incubation. The ratio of substrate to primer appears to be a special factor; higher ratios retard synthesis (S:P 5:1, 1.14%, S:P 100:1, 0.36% incorporation), while lower ones enhance (reaching a maximum of 11.35% at an S:P ratio of 1.75 in hr). Inulin in place of the native fructan is less efficient as primer. Each of the higher homologues of sucrose, tri to hexasaccharides (tested so far), leads to fructan formation with elution volumes from a Sephadex G-25 column close to that of the primer. U- 14 C fructose or glucose in place of U- 14 C sucrose or absence of enzyme leads to no incorporation. Sucrose seems to have a key role both in the initiation and lengthening of the fructan chain. (author)

  14. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

  15. Recent advances in the elucidation of enzymatic function in natural product biosynthesis.

    Science.gov (United States)

    Tan, Gao-Yi; Deng, Zixin; Liu, Tiangang

    2015-01-01

    With the successful production of artemisinic acid in yeast, the promising potential of synthetic biology for natural product biosynthesis is now being realized. The recent total biosynthesis of opioids in microbes is considered to be another landmark in this field. The importance and significance of enzymes in natural product biosynthetic pathways have been re-emphasized by these advancements. Therefore, the characterization and elucidation of enzymatic function in natural product biosynthesis are undoubtedly fundamental for the development of new drugs and the heterologous biosynthesis of active natural products. Here, discoveries regarding enzymatic function in natural product biosynthesis over the past year are briefly reviewed.

  16. Chemical dependence - resources

    Science.gov (United States)

    Substance use - resources, Drug abuse - resources; Resources - chemical dependence ... organizations are a good resource for information on drug dependence: National Council on Alcoholism and Drug Dependence -- ncadd. ...

  17. Regulatory cross-talks and cascades in rice hormone biosynthesis pathways contribute to stress signaling

    Directory of Open Access Journals (Sweden)

    Arindam Deb

    2016-08-01

    Full Text Available Crosstalk among different hormone signaling pathways play an important role in modulating plant response to both biotic and abiotic stress. Hormone activity is controlled by its bio-availability, which is again influenced by its biosynthesis. Thus independent hormone biosynthesis pathways must be regulated and co-ordinated to mount an integrated response. One of the possibilities is to use cis-regulatory elements to orchestrate expression of hormone biosynthesis genes. Analysis of CREs, associated with differentially expressed hormone biosynthesis related genes in rice leaf under Magnaporthe oryzae attack and drought stress enabled us to obtain insights about cross-talk among hormone biosynthesis pathways at the transcriptional level. We identified some master transcription regulators that co-ordinate different hormone biosynthesis pathways under stress. We found that Abscisic acid and Brassinosteroid regulate Cytokinin conjugation; conversely Brassinosteroid biosynthesis is affected by both Abscisic acid and Cytokinin. Jasmonic acid and Ethylene biosynthesis may be modulated by Abscisic acid through DREB transcription factors. Jasmonic acid or Salicylic acid biosynthesis pathways are co-regulated but they are unlikely to influence each other’s production directly. Thus multiple hormones may modulate hormone biosynthesis pathways through a complex regulatory network, where biosynthesis of one hormone is affected by several other contributing hormones.

  18. Uranium resources

    International Nuclear Information System (INIS)

    1976-01-01

    This is a press release issued by the OECD on 9th March 1976. It is stated that the steep increases in demand for uranium foreseen in and beyond the 1980's, with doubling times of the order of six to seven years, will inevitably create formidable problems for the industry. Further substantial efforts will be needed in prospecting for new uranium reserves. Information is given in tabular or graphical form on the following: reasonably assured resources, country by country; uranium production capacities, country by country; world nuclear power growth; world annual uranium requirements; world annual separative requirements; world annual light water reactor fuel reprocessing requirements; distribution of reactor types (LWR, SGHWR, AGR, HWR, HJR, GG, FBR); and world fuel cycle capital requirements. The information is based on the latest report on Uranium Resources Production and Demand, jointly issued by the OECD's Nuclear Energy Agency (NEA) and the International Atomic Energy Agency. (U.K.)

  19. Algae Resources

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    Algae are highly efficient at producing biomass, and they can be found all over the planet. Many use sunlight and nutrients to create biomass, which contain key components—including lipids, proteins, and carbohydrates— that can be converted and upgraded to a variety of biofuels and products. A functional algal biofuels production system requires resources such as suitable land and climate, sustainable management of water resources, a supplemental carbon dioxide (CO2) supply, and other nutrients (e.g., nitrogen and phosphorus). Algae can be an attractive feedstock for many locations in the United States because their diversity allows for highpotential biomass yields in a variety of climates and environments. Depending on the strain, algae can grow by using fresh, saline, or brackish water from surface water sources, groundwater, or seawater. Additionally, they can grow in water from second-use sources such as treated industrial wastewater; municipal, agricultural, or aquaculture wastewater; or produced water generated from oil and gas drilling operations.

  20. Biosynthesis of butyric acid by Clostridium tyrobutyricum.

    Science.gov (United States)

    Huang, Jin; Tang, Wan; Zhu, Shengquan; Du, Meini

    2018-03-21

    Butyric acid (C 3 H 7 COOH) is an important chemical that is widely used in foodstuffs along with in the chemical and pharmaceutical industries. The bioproduction of butyric acid via large-scale fermentation has the potential to be more economical and efficient than petrochemical synthesis. In this paper, the metabolic pathways involved in the production of butyric acid from Clostridium tyrobutyricum using hexose and pentose as substrates are investigated, and approaches to enhance butyric acid production via genetic modification are discussed. Finally, bioreactor modifications (including fibrous bed bioreactor, inner disc-shaped matrix bioreactor, fibrous matrix packed in porous levitated sphere carriers), low-cost feedstocks and special treatments (including continuous fermentation with cell recycling, extractive fermentation with solvent, using different artificial electron carriers) intended to improve the feasibility of commercial butyric acid bioproduction are summarized.

  1. Resource Abundance and Resource Dependence in China

    NARCIS (Netherlands)

    Ji, K.; Magnus, J.R.; Wang, W.

    2010-01-01

    This paper reconsiders the ‘curse of resources’ hypothesis for the case of China, and distinguishes between resource abundance, resource rents, and resource dependence. Resource abundance and resource rents are shown to be approximately equivalent, and their association with resource dependence

  2. Gamma-aminobutyric acid mediates nicotine biosynthesis in tobacco under flooding stress

    Directory of Open Access Journals (Sweden)

    Xiaoming Zhang

    2016-02-01

    Full Text Available Gamma-aminobutyric acid (GABA is a four-carbon non-protein amino acid conserved from bacteria to plants and vertebrates. Increasing evidence supports a regulatory role for GABA in plant development and the plant's response to environmental stress. The biosynthesis of nicotine, the main economically important metabolite in tobacco, is tightly regulated. GABA has not hitherto been reported to function in nicotine biosynthesis. Here we report that water flooding treatment (hypoxia markedly induced the accumulation of GABA and stimulated nicotine biosynthesis. Suppressing GABA accumulation by treatment with glutamate decarboxylase inhibitor impaired flooding-induced nicotine biosynthesis, while exogenous GABA application directly induced nicotine biosynthesis. Based on these results, we propose that GABA triggers nicotine biosynthesis in tobacco seedlings subjected to flooding. Our results provide insight into the molecular mechanism of nicotine biosynthesis in tobacco plants exposed to environmental stress.

  3. Biosynthesis of titanium dioxide nanoparticles using Bacillus amyloliquefaciens culture and enhancement of its photocatalytic activity for the degradation of a sulfonated textile dye Reactive Red 31.

    Science.gov (United States)

    Khan, Razia; Fulekar, M H

    2016-08-01

    The present study aims at exploiting Bacillus amyloliquefaciens for the biosynthesis of titanium dioxide nanoparticles and also investigates role of bacterial enzymes in the biosynthesis of titanium dioxide nanoparticles. Bacterial synthesized as well as metal doped titanium dioxide nanoparticles were characterized by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDAX). Amylase activity (43.37IU) in culture supernatant evinced a potential involvement of extracellular enzyme in TiO2 nanoparticle biosynthesis. Crystallite size of bio-synthesized nanoparticles was found to be in the range of 15.23-87.6nm. FTIR spectroscopy and native-PAGE (Polyacrylamide Gel Electrophoresis) clearly indicated involvement of alpha amylase in biosynthesis of TiO2 nanoparticles and in their stabilization. TEM micrographs of the synthesized titanium dioxide nanoparticles revealed the formation of spherical nanoparticles with a size range of 22.11-97.28nm. Photocatalytic degradation of Reactive Red 31 (RR31) dye was carried out using bio-synthesized TiO2 nanoparticles under UV radiation. Photocatalytic activity of synthesized nanoparticles was enhanced by Ag, La, Zn and Pt doping. Platinum doped TiO2 showed highest potential (90.98%) in RR31 degradation as compared to undoped (75.83%). Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Electron radiography

    Science.gov (United States)

    Merrill, Frank E.; Morris, Christopher

    2005-05-17

    A system capable of performing radiography using a beam of electrons. Diffuser means receive a beam of electrons and diffuse the electrons before they enter first matching quadrupoles where the diffused electrons are focused prior to the diffused electrons entering an object. First imaging quadrupoles receive the focused diffused electrons after the focused diffused electrons have been scattered by the object for focusing the scattered electrons. Collimator means receive the scattered electrons and remove scattered electrons that have scattered to large angles. Second imaging quadrupoles receive the collimated scattered electrons and refocus the collimated scattered electrons and map the focused collimated scattered electrons to transverse locations on an image plane representative of the electrons' positions in the object.

  5. World resources of oil products

    International Nuclear Information System (INIS)

    Bonnaterre, Raymond

    2014-01-01

    In a first part, the author outlines that the issue of density of an oil product raises the question of the validity of a counting approach based on volumes. As oil industries produce always less heavy products and always more light products, this means that always less oil is needed to produce a gallon or a litre of fuel out of a refinery. The author comments the evolution of crude oil extraction. In a second part, he outlines that hydrocarbon productions become always more complex with respect to their origin. Thus, during gas extraction, humid gases are recovered which contain an important part of hydrocarbons similar to light oil. These aspects and the development of shale gas exploitation will make the USA the first oil producer in the world whereas they still have to import heavy oil to feed their refineries. He discusses the level of reserves and production costs with respect to the product type or its extraction location. He discusses the evolution of the estimates of world ultimately recoverable resources (synthesis processes excluded). He comments the level of condensate extraction ratio of the main shale gas fields in the USA and outlines the cost of natural gas imports for France. He outlines the importance of GTL (gas to liquid) processes, the increasing importance of bio-fuels (notably isobutanol biosynthesis and terpene biosynthesis). In the third part, the author states that the barrel price should keep on increasing and, in the fourth part, proposes a list of issues which will impact the future of the oil market

  6. Concholepas hemocyanin biosynthesis takes place in the hepatopancreas, with hemocytes being involved in its metabolism.

    Science.gov (United States)

    Manubens, Augusto; Salazar, Fabián; Haussmann, Denise; Figueroa, Jaime; Del Campo, Miguel; Pinto, Jonathan Martínez; Huaquín, Laura; Venegas, Alejandro; Becker, María Inés

    2010-12-01

    Hemocyanins are copper-containing glycoproteins in some molluscs and arthropods, and their best-known function is O(2) transport. We studied the site of their biosynthesis in the gastropod Concholepas concholepas by using immunological and molecular genetic approaches. We performed immunohistochemical staining of various organs, including the mantle, branchia, and hepatopancreas, and detected C. concholepas hemocyanin (CCH) molecules in circulating and tissue-associated hemocytes by electron microscopy. To characterize the hemocytes, we purified them from hemolymph. We identified three types of granular cells. The most abundant type was a phagocyte-like cell with small cytoplasmic granules. The second type contained large electron-dense granules. The third type had vacuoles containing hemocyanin molecules suggesting that synthesis or catabolism occurred inside these cells. Our failure to detect cch-mRNA in hemocytes by reverse transcription with the polymerase chain reaction (RT-PCR) led us to propose that hemocytes instead played a role in CCH metabolism. This hypothesis was supported by colloidal gold staining showing hemocyanin molecules in electron-dense granules inside hemocytes. RT-PCR analysis, complemented by in situ hybridization analyses with single-stranded antisense RNAs as specific probes, demonstrated the presence of cch-mRNA in the hepatopancreas; this was consistent with the specific hybridization signal and confirmed the hepatopancreas as the site of CCH synthesis. Finally, we investigated the possibility that CCH catabolism in hemocytes was involved in the host immune response and in the generation of secondary metabolites such as antimicrobial peptides and phenoloxidase.

  7. In Vivo Roles of Fatty Acid Biosynthesis Enzymes in Biosynthesis of Biotin and α-Lipoic Acid in Corynebacterium glutamicum.

    Science.gov (United States)

    Ikeda, Masato; Nagashima, Takashi; Nakamura, Eri; Kato, Ryosuke; Ohshita, Masakazu; Hayashi, Mikiro; Takeno, Seiki

    2017-10-01

    For fatty acid biosynthesis, Corynebacterium glutamicum uses two type I fatty acid synthases (FAS-I), FasA and FasB, in addition to acetyl-coenzyme A (CoA) carboxylase (ACC) consisting of AccBC, AccD1, and AccE. The in vivo roles of the enzymes in supplying precursors for biotin and α-lipoic acid remain unclear. Here, we report genetic evidence demonstrating that the biosynthesis of these cofactors is linked to fatty acid biosynthesis through the FAS-I pathway. For this study, we used wild-type C. glutamicum and its derived biotin vitamer producer BFI-5, which was engineered to express Escherichia coli bioBF and Bacillus subtilis bioI Disruption of either fasA or fasB in strain BFI-5 led to decreased production of biotin vitamers, whereas its amplification contributed to increased production, with a larger impact of fasA in both cases. Double disruptions of fasA and fasB resulted in no biotin vitamer production. The acc genes showed a positive effect on production when amplified simultaneously. Augmented fatty acid biosynthesis was also reflected in pimelic acid production when carbon flow was blocked at the BioF reaction. These results indicate that carbon flow down the FAS-I pathway is destined for channeling into the biotin biosynthesis pathway, and that FasA in particular has a significant impact on precursor supply. In contrast, fasB disruption resulted in auxotrophy for lipoic acid or its precursor octanoic acid in both wild-type and BFI-5 strains. The phenotypes were fully complemented by plasmid-mediated expression of fasB but not fasA These results reveal that FasB plays a specific physiological role in lipoic acid biosynthesis in C. glutamicum IMPORTANCE For the de novo biosynthesis of fatty acids, C. glutamicum exceptionally uses a eukaryotic multifunctional type I fatty acid synthase (FAS-I) system comprising FasA and FasB, in contrast to most bacteria, such as E. coli and B. subtilis , which use an individual nonaggregating type II fatty acid synthase

  8. Biosynthesis of highly porous bacterial cellulose nanofibers

    Science.gov (United States)

    Hosseini, Hadi; Kokabi, Mehrdad; Mousavi, Seyyed Mohammad

    2018-01-01

    Bacterial cellulose nanofibers (BCNFs) as a sustainable and biodegradable polymer has drawn tremendous research attention in tissue engineering, bacterial sensors and drug delivery due to its extraordinary properties such as high purity, high crystallinity, high water absorption capacity and excellent mechanical strength in the wet state. This awesome properties, is attributed to BCNFs structure, therefore its characterization is important. In this work, the bacterial strain, Gluconacetobacter xylinus (PTCC 1734, obtained from Iranian Research Organization for Science and Technology (IROST)), was used to produce BCNFs hydrogel using bacterial fermentation under static condition at 29 °C for 10 days in the incubator. Then, the biosynthesized BCNFs wet gel, were dried at ambient temperature and pressure and characterized using Brunauer-Emmett-Teller (BET) and Field emission scanning electron microscopy (FE-SEM) analysis. FESEM image displayed highly interconnected and porous structure composed of web-like continuous, nanofibers with an average diameter of 48.5±2.1 nm. BET result analysis depicted BCNFs dried at ambient conditions had IV isotherm type, according to the IUPAC classification, indicating that BCNFs dried at ambient condition is essentially mesoporous. On the other hand, BET results depicted, mesoporous structure is around 85%. In addition, Specific surface area (SBET) obtained 81.45 m2/g. These results are in accordance with the FESEM observation.

  9. Extracellular bio-synthesis of silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Abdullah Yousif Obaid

    2017-02-01

    Full Text Available The effect of cetyltrimethylammonium bromide, CTAB has been studied on the optical properties and morphology of advanced Ag-nanoparticles (AgNPs using Oriental plane leaves extract as a reducing-, stabilizing- and capping-agent for the first time. The formation of Ag-nanodisks was monitored by measuring the UV–vis spectra at different time intervals (5, 10, 20 and 30 min after adding the leaves extract (from 1 to 5 cm3 to the different AgNO3 solutions ([Ag+] = 4.0, 8.0, 12.0, 16.0 × 10−4 mol dm−3. The sigmoidal nature of the reaction-time plots suggests the involvements of an autocatalytic reaction path. In the presence of CTAB, the peak at 450 nm is shifted to shorter wavelength, i.e., 425 nm and sharpness of the surface resonance plasmon (SRP band also decreases. The results confirm a significant change in the morphology and/or agglomeration tendency with CTAB. Transmission electron microscopy (TEM results show the formation of stable AgNPs at different concentration of AgNO3 gives mostly spherical particles with diameter ranging from 10 to 30 nm.

  10. Energy resources

    CERN Document Server

    Simon, Andrew L

    1975-01-01

    Energy Resources mainly focuses on energy, including its definition, historical perspective, sources, utilization, and conservation. This text first explains what energy is and what its uses are. This book then explains coal, oil, and natural gas, which are some of the common energy sources used by various industries. Other energy sources such as wind, solar, geothermal, water, and nuclear energy sources are also tackled. This text also looks into fusion energy and techniques of energy conversion. This book concludes by explaining the energy allocation and utilization crisis. This publ

  11. Biosynthesis of glycosylated derivatives of tylosin in Streptomyces venezuelae.

    Science.gov (United States)

    Han, Ah Reum; Park, Sung Ryeol; Park, Je Won; Lee, Eun Yeol; Kim, Dong-Myung; Kim, Byung-Gee; Yoon, Yeo Joon

    2011-06-01

    Streptomyces venezuelae YJ028, bearing a deletion of the entire biosynthetic gene cluster encoding the pikromycin polyketide synthases and desosamine biosynthetic enzymes, was used as a bioconversion system for combinatorial biosynthesis of glycosylated derivatives of tylosin. Two engineered deoxysugar biosynthetic pathways for the biosynthesis of TDP-3-O-demethyl-D-chalcose or TDP-Lrhamnose in conjunction with the glycosyltransferaseauxiliary protein pair DesVII/DesVIII were expressed in a S. venezuelae YJ028 mutant strain. Supplementation of each mutant strain capable of producing TDP-3-O-demethyl- D-chalcose or TDP-L-rhamnose with tylosin aglycone tylactone resulted in the production of the 3-O-demethyl- D-chalcose, D-quinovose, or L-rhamnose-glycosylated tylactone.

  12. Biosynthesis of Anthocyanins and Their Regulation in Colored Grapes

    Directory of Open Access Journals (Sweden)

    Guo-Liang Yan

    2010-12-01

    Full Text Available Anthocyanins, synthesized via the flavonoid pathway, are a class of crucial phenolic compounds which are fundamentally responsible for the red color of grapes and wines. As the most important natural colorants in grapes and their products, anthocyanins are also widely studied for their numerous beneficial effects on human health. In recent years, the biosynthetic pathway of anthocyanins in grapes has been thoroughly investigated. Their intracellular transportation and accumulation have also been further clarified. Additionally, the genetic mechanism regulating their biosynthesis and the phytohormone influences on them are better understood. Furthermore, due to their importance in the quality of wine grapes, the effects of the environmental factors and viticulture practices on anthocyanin accumulation are being investigated increasingly. The present paper summarizes both the basic information and the most recent advances in the study of the anthocyanin biosynthesis in red grapes, emphasizing their gene structure, the transcriptional factors and the diverse exterior regulation factors.

  13. Cholesterol biosynthesis in polychlorinated biphenyl-treated rats

    International Nuclear Information System (INIS)

    Kling, D.; Gamble, W.

    1982-01-01

    After administration of polychlorinated biphenly (PCB) at 0.055 (w/w) of the diet to Wistar rats for 30 days, followed by intraperitioneal injection of tritiated water, [ 14 C]mevalonate, and [ 14 C]acetate, there was a decrease in cholesterol biosynthesis in rat liver. No significant change in cholesterol formation was observed when PCB was administered at 0.01% (w/w) of the diet. In vitro inhibition of cholesterol synthesis by rat liver microsomes was observed with PCB. Squalene 2,3-oxidocyclase activity of rat liver microsomes was not significantly altered. Desmosterol delta 24 reductase activity was inhibited only at relatively high concentrations of PCB. There was increased incorporation of radioactivity into squalene and lanosterol, in vitro, in the presence of PCB. The primary inhibition of cholesterol biosynthesis appears to be at the demethylation and rearrangement reactions between lanosterol and cholesterol in the biosynthetic pathway

  14. Biosynthesis of collagen by fibroblasts kept in culture

    International Nuclear Information System (INIS)

    Machado-Santelli, G.M.

    1978-01-01

    The sinthesis of collagen is studied in fibroblasts of different origins with the purpose of obtaining an appropriate system for the study of its biosynthesis and processing. The percentage of collagen synthesis vary according to the fibroblast origin. Experiences are performed with fibroblasts kept in culture from: chicken - and guinea pig embryos, carragheenin - induced granulomas in adult guinea pig and from human skin. The collagen pattern synthesized after acetic acid - or saline extractions in the presence of inhibitors is also determined. This pattern is then assayed by poliacrilamide - 5% - SDS gel electrophoresis accompanied by fluorography. The importance of the cell culture system in the elucidation of collagen biosynthesis is pointed out. (M.A.) [pt

  15. Ovarian ecdysteroid biosynthesis and female germline stem cells.

    Science.gov (United States)

    Ameku, Tomotsune; Yoshinari, Yuto; Fukuda, Ruriko; Niwa, Ryusuke

    2017-07-03

    The germline stem cells (GSCs) are critical for gametogenesis throughout the adult life. Stem cell identity is maintained by local signals from a specialized microenvironment called the niche. However, it is unclear how systemic signals regulate stem cell activity in response to environmental cues. In our previous article, we reported that mating stimulates GSC proliferation in female Drosophila. The mating-induced GSC proliferation is mediated by ovarian ecdysteroids, whose biosynthesis is positively controlled by Sex peptide signaling. Here, we characterized the post-eclosion and post-mating expression pattern of the genes encoding the ecdysteroidogenic enzymes in the ovary. We further investigated the biosynthetic functions of the ovarian ecdysteroid in GSC maintenance in the mated females. We also briefly discuss the regulation of the ecdysteroidogenic enzyme-encoding genes and the subsequent ecdysteroid biosynthesis in the ovary of the adult Drosophila.

  16. A protein interaction map of the kalimantacin biosynthesis assembly line

    Directory of Open Access Journals (Sweden)

    Birgit Uytterhoeven

    2016-11-01

    Full Text Available The antimicrobial secondary metabolite kalimantacin is produced by a hybrid polyketide/ non-ribosomal peptide system in Pseudomonas fluorescens BCCM_ID9359. In this study, the kalimantacin biosynthesis gene cluster is analyzed by yeast two-hybrid analysis, creating a protein-protein interaction map of the entire assembly line. In total, 28 potential interactions were identified, of which 13 could be confirmed further. These interactions include the dimerization of ketosynthase domains, a link between assembly line modules 9 and 10, and a specific interaction between the trans-acting enoyl reductase BatK and the carrier proteins of modules 8 and 10. These interactions reveal fundamental insight into the biosynthesis of secondary metabolites.This study is the first to reveal interactions in a complete biosynthetic pathway. Similar future studies could build a strong basis for engineering strategies in such clusters.

  17. Enzymatic Reductive Dehalogenation Controls the Biosynthesis of Marine Bacterial Pyrroles.

    Science.gov (United States)

    El Gamal, Abrahim; Agarwal, Vinayak; Rahman, Imran; Moore, Bradley S

    2016-10-12

    Enzymes capable of performing dehalogenating reactions have attracted tremendous contemporary attention due to their potential application in the bioremediation of anthropogenic polyhalogenated persistent organic pollutants. Nature, in particular the marine environment, is also a prolific source of polyhalogenated organic natural products. The study of the biosynthesis of these natural products has furnished a diverse array of halogenation biocatalysts, but thus far no examples of dehalogenating enzymes have been reported from a secondary metabolic pathway. Here we show that the penultimate step in the biosynthesis of the highly brominated marine bacterial product pentabromopseudilin is catalyzed by an unusual debrominase Bmp8 that utilizes a redox thiol mechanism to remove the C-2 bromine atom of 2,3,4,5-tetrabromopyrrole to facilitate oxidative coupling to 2,4-dibromophenol. To the best of our knowledge, Bmp8 is first example of a dehalogenating enzyme from the established genetic and biochemical context of a natural product biosynthetic pathway.

  18. Biosynthesis and chemical synthesis of presilphiperfolanol natural products.

    Science.gov (United States)

    Hong, Allen Y; Stoltz, Brian M

    2014-05-19

    Presilphiperfolanols constitute a family of biosynthetically important sesquiterpenes which can rearrange to diverse sesquiterpenoid skeletons. While the origin of these natural products can be traced to simple linear terpene precursors, the details of the enzymatic cyclization mechanism that forms the stereochemically dense tricyclic skeleton has required extensive biochemical, computational, and synthetic investigation. Parallel efforts to prepare the unique and intriguing structures of these compounds by total synthesis have also inspired novel strategies, thus resulting in four synthetic approaches and two completed syntheses. While the biosynthesis and chemical synthesis studies performed to date have provided much insight into the role and properties of these molecules, emerging questions regarding the biosynthesis of newer members of the family and subtle details of rearrangement mechanisms have yet to be explored. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Engineering fatty acid biosynthesis in microalgae for sustainable biodiesel.

    Science.gov (United States)

    Blatti, Jillian L; Michaud, Jennifer; Burkart, Michael D

    2013-06-01

    Microalgae are a promising feedstock for biodiesel and other liquid fuels due to their fast growth rate, high lipid yields, and ability to grow in a broad range of environments. However, many microalgae achieve maximal lipid yields only under stress conditions hindering growth and providing compositions not ideal for biofuel applications. Metabolic engineering of algal fatty acid biosynthesis promises to create strains capable of economically producing fungible and sustainable biofuels. The algal fatty acid biosynthetic pathway has been deduced by homology to bacterial and plant systems, and much of our understanding is gleaned from basic studies in these systems. However, successful engineering of lipid metabolism in algae will necessitate a thorough characterization of the algal fatty acid synthase (FAS) including protein-protein interactions and regulation. This review describes recent efforts to engineer fatty acid biosynthesis toward optimizing microalgae as a biodiesel feedstock. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Transcriptional profiling of sweetpotato (Ipomoea batatas) roots indicates down-regulation of lignin biosynthesis and up-regulation of starch biosynthesis at an early stage of storage root formation.

    Science.gov (United States)

    Firon, Nurit; LaBonte, Don; Villordon, Arthur; Kfir, Yanir; Solis, Julio; Lapis, Evgenia; Perlman, Temima Schnitzer; Doron-Faigenboim, Adi; Hetzroni, Amots; Althan, Leviah; Adani Nadir, Lahan

    2013-07-09

    The number of fibrous roots that develop into storage roots determines sweetpotato yield. The aim of the present study was to identify the molecular mechanisms involved in the initiation of storage root formation, by performing a detailed transcriptomic analysis of initiating storage roots using next-generation sequencing platforms. A two-step approach was undertaken: (1) generating a database for the sweetpotato root transcriptome using 454-Roche sequencing of a cDNA library created from pooled samples of two root types: fibrous and initiating storage roots; (2) comparing the expression profiles of initiating storage roots and fibrous roots, using the Illumina Genome Analyzer to sequence cDNA libraries of the two root types and map the data onto the root transcriptome database. Use of the 454-Roche platform generated a total of 524,607 reads, 85.6% of which were clustered into 55,296 contigs that matched 40,278 known genes. The reads, generated by the Illumina Genome Analyzer, were found to map to 31,284 contigs out of the 55,296 contigs serving as the database. A total of 8,353 contigs were found to exhibit differential expression between the two root types (at least 2.5-fold change). The Illumina-based differential expression results were validated for nine putative genes using quantitative real-time PCR. The differential expression profiles indicated down-regulation of classical root functions, such as transport, as well as down-regulation of lignin biosynthesis in initiating storage roots, and up-regulation of carbohydrate metabolism and starch biosynthesis. In addition, data indicated delicate control of regulators of meristematic tissue identity and maintenance, associated with the initiation of storage root formation. This study adds a valuable resource of sweetpotato root transcript sequences to available data, facilitating the identification of genes of interest. This resource enabled us to identify genes that are involved in the earliest stage of storage

  1. Transcriptional profiling of sweetpotato (Ipomoea batatas) roots indicates down-regulation of lignin biosynthesis and up-regulation of starch biosynthesis at an early stage of storage root formation

    Science.gov (United States)

    2013-01-01

    Background The number of fibrous roots that develop into storage roots determines sweetpotato yield. The aim of the present study was to identify the molecular mechanisms involved in the initiation of storage root formation, by performing a detailed transcriptomic analysis of initiating storage roots using next-generation sequencing platforms. A two-step approach was undertaken: (1) generating a database for the sweetpotato root transcriptome using 454-Roche sequencing of a cDNA library created from pooled samples of two root types: fibrous and initiating storage roots; (2) comparing the expression profiles of initiating storage roots and fibrous roots, using the Illumina Genome Analyzer to sequence cDNA libraries of the two root types and map the data onto the root transcriptome database. Results Use of the 454-Roche platform generated a total of 524,607 reads, 85.6% of which were clustered into 55,296 contigs that matched 40,278 known genes. The reads, generated by the Illumina Genome Analyzer, were found to map to 31,284 contigs out of the 55,296 contigs serving as the database. A total of 8,353 contigs were found to exhibit differential expression between the two root types (at least 2.5-fold change). The Illumina-based differential expression results were validated for nine putative genes using quantitative real-time PCR. The differential expression profiles indicated down-regulation of classical root functions, such as transport, as well as down-regulation of lignin biosynthesis in initiating storage roots, and up-regulation of carbohydrate metabolism and starch biosynthesis. In addition, data indicated delicate control of regulators of meristematic tissue identity and maintenance, associated with the initiation of storage root formation. Conclusions This study adds a valuable resource of sweetpotato root transcript sequences to available data, facilitating the identification of genes of interest. This resource enabled us to identify genes that are involved

  2. From Cholesterogenesis to Steroidogenesis: Role of Riboflavin and Flavoenzymes in the Biosynthesis of Vitamin D12

    Science.gov (United States)

    Pinto, John T.; Cooper, Arthur J. L.

    2014-01-01

    Flavin-dependent monooxygenases and oxidoreductases are located at critical branch points in the biosynthesis and metabolism of cholesterol and vitamin D. These flavoproteins function as obligatory intermediates that accept 2 electrons from NAD(P)H with subsequent 1-electron transfers to a variety of cytochrome P450 (CYP) heme proteins within the mitochondria matrix (type I) and the (microsomal) endoplasmic reticulum (type II). The mode of electron transfer in these systems differs slightly in the number and form of the flavin prosthetic moiety. In the type I mitochondrial system, FAD-adrenodoxin reductase interfaces with adrenodoxin before electron transfer to CYP heme proteins. In the microsomal type II system, a diflavin (FAD/FMN)-dependent cytochrome P450 oxidoreductase [NAD(P)H-cytochrome P450 reductase (CPR)] donates electrons to a multitude of heme oxygenases. Both flavoenzyme complexes exhibit a commonality of function with all CYP enzymes and are crucial for maintaining a balance of cholesterol and vitamin D metabolites. Deficits in riboflavin availability, imbalances in the intracellular ratio of FAD to FMN, and mutations that affect flavin binding domains and/or interactions with client proteins result in marked structural alterations within the skeletal and central nervous systems similar to those of disorders (inborn errors) in the biosynthetic pathways that lead to cholesterol, steroid hormones, and vitamin D and their metabolites. Studies of riboflavin deficiency during embryonic development demonstrate congenital malformations similar to those associated with genetic alterations of the flavoenzymes in these pathways. Overall, a deeper understanding of the role of riboflavin in these pathways may prove essential to targeted therapeutic designs aimed at cholesterol and vitamin D metabolism. PMID:24618756

  3. Biosynthesis of Titanium Dioxide Nanoparticles and Their Antibacterial Property

    OpenAIRE

    Prachi Singh

    2016-01-01

    This paper presents a low-cost, eco-friendly and reproducible microbe mediated biosynthesis of TiO2 nanoparticles. TiO2 nanoparticles synthesized using the bacterium, Bacillus subtilis, from titanium as a precursor, were confirmed by TEM analysis. The morphological characteristics state spherical shape, with the size of individual or aggregate nanoparticles, around 30-40 nm. Microbial resistance represents a challenge for the scientific community to develop new bioactive compounds. Here, the ...

  4. Oxylipin Pathway in the Biosynthesis of Fresh Tomato Volatiles

    OpenAIRE

    YILMAZ, Emin

    2001-01-01

    Fresh tomato volatiles are formed in intact fruit during ripening and upon tissue disruption. There are different pathways involved in the biosynthesis of these volatiles. The oxylipin pathway uses free unsaturated fatty acids with the sequential action of lipoxygenase, hydroperoxide lyase and alcohol dehydrogenase to produce volatile aldehyde and alcohol compounds. Oxylipin volatiles are the most important components in fresh tomato aroma. In order to genetically improve the quality of tomat...

  5. Biosynthesis and Application of Silver and Gold Nanoparticles

    OpenAIRE

    Sadowski, Zygmunt

    2010-01-01

    A green chemistry synthetic route has been used for both silver and gold nanoparticles synthesis. The reaction occurred at ambient temperature. Among the nanoparticles biological organism, some microorganisms such as bacteria, fungi, and yeast have been exploited for nanoparticles synthesis. Several plant biomass or plant extracts have been successfully used for extracellular biosynthesis of silver and gold nanoparticles. Analytical techniques, such as ultraviolet-visible spectroscopy (UV-vis...

  6. Biosynthesis of sterols and ecdysteroids in Ajuga hairy roots.

    Science.gov (United States)

    Fujimoto, Y; Ohyama, K; Nomura, K; Hyodo, R; Takahashi, K; Yamada, J; Morisaki, M

    2000-03-01

    Hairy roots of Ajuga reptans var. atropurpurea produce clerosterol, 22-dehydroclerosterol, and cholesterol as sterol constituents, and 20-hydroxyecdysone, cyasterone, isocyasterone, and 29-norcyasterone as ecdysteroid constituents. To better understand the biosynthesis of these steroidal compounds, we carried out feeding studies of variously 2H- and 13C-labeled sterol substrates with Ajuga hairy roots. In this article, we review our studies in this field. Feeding of labeled desmosterols, 24-methylenecholesterol, and 13C2-acetate established the mechanism of the biosynthesis of the two C29-sterols and a newly accumulated codisterol, including the metabolic correlation of C-26 and C-27 methyl groups. In Ajuga hairy roots, 3alpha-, 4alpha-, and 4beta-hydrogens of cholesterol were all retained at their original positions after conversion into 20-hydroxyecdysone, in contrast to the observations in a fern and an insect. Furthermore, the origin of 5beta-H of 20-hydroxyecdysone was found to be C-6 hydrogen of cholesterol exclusively, which is inconsistent with the results in the fern and the insect. These data strongly support the intermediacy of 7-dehydrocholesterol 5alpha,6alpha-epoxide. Moreover, 7-dehydrocholesterol, 3beta-hydroxy-5beta-cholest-7-en-6-one (5beta-ketol), and 3beta,14alpha-dihydroxy-5beta-cholest-7-en-6-one (5beta-ketodiol) were converted into 20-hydroxyecdysone. Thus, the pathway cholesterol-->7-dehydrocholesterol-->7-dehydrocholesterol 5alpha,6alpha-epoxide-->5beta-ketol-->5beta-k etodiol is proposed for the early stages of 20-hydroxyecdysone biosynthesis. 3beta-Hydroxy-5beta-cholestan-6-one was also incorporated into 20-hydroxyecdysone, suggesting that the introduction of a 7-ene function is not necessarily next to cholesterol. C-25 Hydroxylation during 20-hydroxyecdysone biosynthesis was found to proceed with ca. 70% retention and 30% inversion. Finally, clerosterol was shown to be a precursor of cyasterone and isocyasterone.

  7. Biosynthesis and engineering of kaempferol in Saccharomyces cerevisiae

    OpenAIRE

    Duan, Lijin; Ding, Wentao; Liu, Xiaonan; Cheng, Xiaozhi; Cai, Jing; Hua, Erbing; Jiang, Huifeng

    2017-01-01

    Background Kaempferol is a flavonol with broad bioactivity of anti-oxidant, anti-cancer, anti-diabetic, anti-microbial, cardio-protective and anti-asthma. Microbial synthesis of kaempferol is a promising strategy because of the low content in primary plant source. Methods In this study, the biosynthesis pathway of kaempferol was constructed in the budding yeast Saccharomyces cerevisiae to produce kaempferol de novo, and several biological measures were taken for high production. Results First...

  8. Sex differences in prostaglandin biosynthesis in neutrophils during acute inflammation

    OpenAIRE

    Pace, Simona; Rossi, Antonietta; Krauth, Verena; Dehm, Friederike; Troisi, Fabiana; Bilancia, Rossella; Weinigel, Christina; Rummler, Silke; Werz, Oliver; Sautebin, Lidia

    2017-01-01

    The severity and course of inflammatory processes differ between women and men, but the biochemical mechanisms underlying these sex differences are elusive. Prostaglandins (PG) and leukotrienes (LT) are lipid mediators linked to inflammation. We demonstrated superior LT biosynthesis in human neutrophils and monocytes, and in mouse macrophages from females, and we confirmed these sex differences in vivo where female mice produced more LTs during zymosan-induced peritonitis versus males. Here, ...

  9. Biosynthesis and regulation of cyclic lipopeptides in Pseudomonas fluorescens

    OpenAIRE

    Bruijn, de, I.

    2009-01-01

    Cyclic lipopeptides (CLPs) are surfactant and antibiotic metabolites produced by a variety of bacterial genera. For the genus Pseudomonas, many structurally different CLPs have been identified. CLPs play an important role in surface motility of Pseudomonas strains, but also in virulence and attachment/detachment to and from surfaces. In this Ph.D. thesis project, two new CLP biosynthesis clusters were identified in Pseudomonas fluorescens and fully sequenced. In P. fluorescens strain SBW2...

  10. Engineered polyketide biosynthesis and biocatalysis in Escherichia coli

    OpenAIRE

    Gao, Xue; Wang, Peng; Tang, Yi

    2010-01-01

    Polyketides are important bioactive natural products biosynthesized by bacteria, fungi, and plants. The enzymes that synthesize polyketides are collectively referred to as polyketide synthases (PKSs). Because many of the natural hosts that produce polyketides are difficult to culture or manipulate, establishing a universal heterologous host that is genetically tractable has become an important goal toward the engineered biosynthesis of polyketides and analogues. Here, we summarize the recent ...

  11. Engineered biosynthesis of bacterial aromatic polyketides in Escherichia coli.

    Science.gov (United States)

    Zhang, Wenjun; Li, Yanran; Tang, Yi

    2008-12-30

    Bacterial aromatic polyketides are important therapeutic compounds including front line antibiotics and anticancer drugs. It is one of the last remaining major classes of natural products of which the biosynthesis has not been reconstituted in the genetically superior host Escherichia coli. Here, we demonstrate the engineered biosynthesis of bacterial aromatic polyketides in E. coli by using a dissected and reassembled fungal polyketide synthase (PKS). The minimal PKS of the megasynthase PKS4 from Gibberella fujikuroi was extracted by using two approaches. The first approach yielded a stand-alone Ketosynthase (KS)_malonyl-CoA:ACP transferase (MAT) didomain and an acyl-carrier protein (ACP) domain, whereas the second approach yielded a compact PKS (PKS_WJ) that consists of KS, MAT, and ACP on a single polypeptide. Both minimal PKSs produced nonfungal polyketides cyclized via different regioselectivity, whereas the fungal-specific C2-C7 cyclization mode was not observed. The kinetic properties of the two minimal PKSs were characterized to confirm both PKSs can synthesize polyketides with similar efficiency as the parent PKS4 megasynthase. Both minimal PKSs interacted effectively with exogenous polyketide cyclases as demonstrated by the synthesis of predominantly PK8 3 or NonaSEK4 6 in the presence of a C9-C14 or a C7-C12 cyclase, respectively. When PKS_WJ and downstream tailoring enzymes were expressed in E. coli, the expected nonaketide anthraquinone SEK26 was recovered in good titer. High-cell density fermentation was performed to demonstrate the scale-up potential of the in vivo platform for the biosynthesis of bacterial polyketides. Using engineered fungal PKSs can therefore be a general approach toward the heterologous biosynthesis of bacterial aromatic polyketides in E. coli.

  12. A new strategy for aromatic ring alkylation in cylindrocyclophane biosynthesis.

    Science.gov (United States)

    Nakamura, Hitomi; Schultz, Erica E; Balskus, Emily P

    2017-08-01

    Alkylation of aromatic rings with alkyl halides is an important transformation in organic synthesis, yet an enzymatic equivalent is unknown. Here, we report that cylindrocyclophane biosynthesis in Cylindrospermum licheniforme ATCC 29412 involves chlorination of an unactivated carbon center by a novel halogenase, followed by a previously uncharacterized enzymatic dimerization reaction featuring sequential, stereospecific alkylations of resorcinol aromatic rings. Discovery of the enzymatic machinery underlying this unique biosynthetic carbon-carbon bond formation has implications for biocatalysis and metabolic engineering.

  13. Regulation of Neurosteroid Biosynthesis by Neurotransmitters and Neuropeptides

    OpenAIRE

    Do Rego, Jean Luc; Seong, Jae Young; Burel, Delphine; Leprince, Jerôme; Vaudry, David; Luu-The, Van; Tonon, Marie-Christine; Tsutsui, Kazuyoshi; Pelletier, Georges; Vaudry, Hubert

    2012-01-01

    The enzymatic pathways leading to the synthesis of bioactive steroids in the brain are now almost completely elucidated in various groups of vertebrates and, during the last decade, the neuronal mechanisms involved in the regulation of neurosteroid production have received increasing attention. This report reviews the current knowledge concerning the effects of neurotransmitters, peptide hormones, and neuropeptides on the biosynthesis of neurosteroids. Anatomical studies have been carried out...

  14. Regulation of neurosteroid biosynthesis by neurotransmitters and neuropeptides

    Directory of Open Access Journals (Sweden)

    Jean-Luc eDo-Rego

    2012-01-01

    Full Text Available The enzymatic pathways leading to the synthesis of bioactive steroids in the brain are now almost completely elucidated in various groups of vertebrates and, during the last decade, the neuronal mechanisms involved in the regulation of neurosteroid production have received increasing attention. This report reviews the current knowledge concerning the effects of neurotransmitters, peptide hormones and neuropeptides on the biosynthesis of neurosteroids. Anatomical studies have been carried out to visualize the neurotransmitter- or neuropeptide-containing fibers contacting steroid-synthesizing neurons as well as the neurotransmitter, peptide hormones or neuropeptide receptors expressed in these neurons. Biochemical experiments have been conducted to investigate the effects of neurotransmitters, peptide hormones or neuropeptides on neurosteroid biosynthesis, and to characterize the type of receptors involved. Thus, it has been found that glutamate, acting through kainate and/or AMPA receptors, rapidly inactivates P450arom, and that melatonin produced by the pineal gland and eye inhibits the biosynthesis of 7-hydroxypregnenolone (7-OH-5P, while prolactin produced by the adenohypophysis enhances the formation of 7-OH-5P. It has also been demonstrated that the biosynthesis of neurosteroids is inhibited by GABA, acting through GABAA receptors, and neuropeptide Y, acting through Y1 receptors. In contrast, it has been shown that the octadecaneuropetide ODN, acting through central-type benzodiazepine receptors, the triakontatetraneuropeptide TTN, acting though peripheral-type benzodiazepine receptors, and vasotocine, acting through V1a-like receptors, stimulate the production of neurosteroids. Since neurosteroids are implicated in the control of various neurophysiological and behavioral processes, these data suggest that some of the neurophysiological effects exerted by neurotransmitters and neuropeptides may be mediated via the regulation

  15. ENDOCANNABINOIDS AND EICOSAMOIDS: BIOSYNTHESIS AND INTERACTIONS WITH IMMUNE RESPONSE

    Directory of Open Access Journals (Sweden)

    Yu. K. Karaman

    2013-01-01

    Full Text Available The review is dedicated to modern concepts of arachidonic acid metabolites, i.e., endocannabinoids and eicosanoids, their biosynthetic pathways, cross-talk mechanisms and participation in immune response. New information from literature and own results include data concerning overlapping enzymatic pathways controlling biosynthesis of endocannabinoids and eicosanoids. Impact of synthetic cannabinoid receptor ligands upon production rates of proinflammatory cytokines and eicosanoids is discussed, as like as relationships among immune system reactivity and expression levels of cannabinoid receptors.

  16. A Comparison between Chemical Synthesis Magnetite Nanoparticles and Biosynthesis Magnetite

    OpenAIRE

    Seyed Abolghasem Kahani; Zahra Yagini

    2014-01-01

    The preparation of Fe3O4 from ferrous salt by air in alkaline aqueous solution at various temperatures was proposed. The synthetic magnetites have different particle size distributions. We studied the properties of the magnetite prepared by chemical methods compared with magnetotactic bacterial nanoparticles. The results show that crystallite size, morphology, and particle size distribution of chemically prepared magnetite at 293 K are similar to biosynthesis of magnetite. The new preparation...

  17. Protein biosynthesis in isolated human scalp hair follicles.

    Science.gov (United States)

    Vermorken, A J; Weterings, P J; Bloemendal, H

    1979-02-15

    The present study demonstrates that protein biosynthesis can be studied in single isolated human scalp hair follicles. The matrix and the sheath are the main regions where amino acids are built in. Incorporation is linear for at least five hours. The newly synthesized proteins can be separated into a water-soluble, a urea-soluble and a urea-insoluble fraction. Product analysis has been performed on the first two fractions, revealing different protein patterns.

  18. Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species

    OpenAIRE

    Zomorodian, Kamiar; Pourshahid, Seyedmohammad; Sadatsharifi, Arman; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

    2016-01-01

    Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in ...

  19. De novo transcriptome characterization of Lilium 'Sorbonne' and key enzymes related to the flavonoid biosynthesis.

    Science.gov (United States)

    Zhang, Ming-fang; Jiang, Ling-min; Zhang, Dong-mei; Jia, Gui-xia

    2015-02-01

    Lily is an important cut-flower and bulb crop in the commercial market. Here, transcriptome profiling of Lilium 'Sorbonne' was conducted through de novo sequencing based on Illumina platform. This research aims at revealing basic information and data that can be used for applied purposes especially the molecular regulatory information on flower color formation in lily. In total, 36,920,680 short reads which corresponded to 3.32 GB of total nucleotides, were produced through transcriptome sequencing. These reads were assembled into 39,636 Unigenes, of which 30,986 were annotated in Nr, Nt, Swiss-Prot, KEGG, COG, GO databases. Based on the three public protein databases, a total of 32,601 coding sequences were obtained. Meanwhile, 19,242 Unigenes were assigned to 128 KEGG pathways. Those with the greatest representation by unique sequences were for ''metabolic pathways'' (5,406 counts, 28.09 %). Our transcriptome revealed 156 Unigenes that encode key enzymes in the flavonoid biosynthesis pathway including CHS, CHI, F3H, FLS, DFR, etc. MISA software identified 2,762 simple sequence repeats, from which 1,975 primers pairs were designed. Over 2,762 motifs were identified, of which the most frequent was AG/CT (659, 23.86 %), followed by A/T (615, 22.27 %) and CCG/CGG (416, 15.06 %). Based on the results, we believe that the color formation of the Lilium 'Sorbonne' flower was mainly controlled by the flavonoid biosynthesis pathway. Additionally, this research provides initial genetic resources that will be valuable to the lily community for other molecular biology research, and the SSRs will facilitate marker-assisted selection in lily breeding.

  20. Feed-forward regulation of microbisporicin biosynthesis in Microbispora corallina.

    Science.gov (United States)

    Foulston, Lucy; Bibb, Mervyn

    2011-06-01

    Lantibiotics are ribosomally synthesized, posttranslationally modified peptide antibiotics. Microbisporicin is a potent lantibiotic produced by the actinomycete Microbispora corallina and contains unique chlorinated tryptophan and dihydroxyproline residues. The biosynthetic gene cluster for microbisporicin encodes several putative regulatory proteins, including, uniquely, an extracytoplasmic function (ECF) σ factor, σ(MibX), a likely cognate anti-σ factor, MibW, and a potential helix-turn-helix DNA binding protein, MibR. Here we examine the roles of these proteins in regulating microbisporicin biosynthesis. S1 nuclease protection assays were used to determine transcriptional start sites in the microbisporicin gene cluster and confirmed the presence of the likely ECF sigma factor -10 and -35 sequences in five out of six promoters. In contrast, the promoter of mibA, encoding the microbisporicin prepropeptide, has a typical Streptomyces vegetative sigma factor consensus sequence. The ECF sigma factor σ(MibX) was shown to interact with the putative anti-sigma factor MibW in Escherichia coli using bacterial two-hybrid analysis. σ(MibX) autoregulates its own expression but does not directly regulate expression of mibA. On the basis of quantitative reverse transcriptase PCR (qRT-PCR) data, we propose a model for the biosynthesis of microbisporicin in which MibR functions as an essential master regulator and the ECF sigma factor/anti-sigma factor pair, σ(MibX)/MibW, induces feed-forward biosynthesis of microbisporicin and producer immunity.

  1. Dual diaminopimelate biosynthesis pathways in Bacteroides fragilis and Clostridium thermocellum.

    Science.gov (United States)

    Hudson, André O; Klartag, Ayelet; Gilvarg, Charles; Dobson, Renwick C J; Marques, Felipe Garbelini; Leustek, Thomas

    2011-09-01

    Bacteroides fragilis and Clostridium thermocellum were recently found to synthesize diaminopimelate (DAP) by way of LL-DAP aminotransferase. Both species also contain an ortholog of meso-diaminopimelate dehydrogenase (Ddh), suggesting that they may have redundant pathways for DAP biosynthesis. The B. fragilis Ddh ortholog shows low homology with other examples of Ddh and this species belongs to a phylum, the Bacteriodetes, not previously known to contain this enzyme. By contrast, the C. thermocellum ortholog is well conserved with known examples of Ddh. Using in vitro and in vivo assays both the B. fragilis and C. thermocellum enzymes were found to be authentic examples of Ddh, displaying kinetic properties typical of this enzyme. The result indicates that B. fragilis contains a sequence diverged form of Ddh. Phylogenomic analysis of the microbial genome database revealed that 77% of species with a Ddh ortholog also contain a second pathway for DAP biosynthesis suggesting that Ddh evolved as an ancillary mechanism for DAP biosynthesis. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. The Stereochemistry of Complex Polyketide Biosynthesis by Modular Polyketide Synthases

    Directory of Open Access Journals (Sweden)

    David H. Kwan

    2011-07-01

    Full Text Available Polyketides are a diverse class of medically important natural products whose biosynthesis is catalysed by polyketide synthases (PKSs, in a fashion highly analogous to fatty acid biosynthesis. In modular PKSs, the polyketide chain is assembled by the successive condensation of activated carboxylic acid-derived units, where chain extension occurs with the intermediates remaining covalently bound to the enzyme, with the growing polyketide tethered to an acyl carrier domain (ACP. Carboxylated acyl-CoA precursors serve as activated donors that are selected by the acyltransferase domain (AT providing extender units that are added to the growing chain by condensation catalysed by the ketosynthase domain (KS. The action of ketoreductase (KR, dehydratase (DH, and enoylreductase (ER activities can result in unreduced, partially reduced, or fully reduced centres within the polyketide chain depending on which of these enzymes are present and active. The PKS-catalysed assembly process generates stereochemical diversity, because carbon–carbon double bonds may have either cis- or trans- geometry, and because of the chirality of centres bearing hydroxyl groups (where they are retained and branching methyl groups (the latter arising from use of propionate extender units. This review shall cover the studies that have determined the stereochemistry in many of the reactions involved in polyketide biosynthesis by modular PKSs.

  3. Purine Biosynthesis Metabolically Constrains Intracellular Survival of Uropathogenic Escherichia coli.

    Science.gov (United States)

    Shaffer, Carrie L; Zhang, Ellisa W; Dudley, Anne G; Dixon, Beverly R E A; Guckes, Kirsten R; Breland, Erin J; Floyd, Kyle A; Casella, Daniel P; Algood, Holly M Scott; Clayton, Douglass B; Hadjifrangiskou, Maria

    2017-01-01

    The ability to de novo synthesize purines has been associated with the intracellular survival of multiple bacterial pathogens. Uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections, undergoes a transient intracellular lifestyle during which bacteria clonally expand into multicellular bacterial communities within the cytoplasm of bladder epithelial cells. Here, we characterized the contribution of the conserved de novo purine biosynthesis-associated locus cvpA-purF to UPEC pathogenesis. Deletion of cvpA-purF, or of purF alone, abolished de novo purine biosynthesis but did not impact bacterial adherence properties in vitro or in the bladder lumen. However, upon internalization by bladder epithelial cells, UPEC deficient in de novo purine biosynthesis was unable to expand into intracytoplasmic bacterial communities over time, unless it was extrachromosomally complemented. These findings indicate that UPEC is deprived of purine nucleotides within the intracellular niche and relies on de novo purine synthesis to meet this metabolic requirement. Copyright © 2016 American Society for Microbiology.

  4. Peroxisomes contribute to biosynthesis of extracellular glycolipids in fungi.

    Science.gov (United States)

    Freitag, Johannes; Ast, Julia; Linne, Uwe; Stehlik, Thorsten; Martorana, Domenica; Bölker, Michael; Sandrock, Björn

    2014-07-01

    Many microorganisms secrete surface-active glycolipids. The basidiomycetous fungus Ustilago maydis produces two different classes of glycolipids, mannosylerythritol lipids (MEL) and ustilagic acids (UAs). Here we report that biosynthesis of MELs is partially localized in peroxisomes and coupled to peroxisomal fatty acid degradation. The acyltransferases, Mac1 and Mac2, which acylate mannosylerythritol with fatty acids of different length, contain a type 1 peroxisomal targeting signal (PTS1). We demonstrate that Mac1 and Mac2 are targeted to peroxisomes, while other enzymes involved in MEL production reside in different compartments. Mis-targeting of Mac1 and Mac2 to the cytosol did not block MEL synthesis but promoted production of MEL species with altered acylation pattern. This is in contrast to peroxisome deficient mutants that produced MELs similar to the wild type. We could show that cytosolic targeting of Mac1 and Mac2 reduces the amount of UA presumably due to competition for overlapping substrates. Interestingly, hydroxylated fatty acids characteristic for UAs appear in MELs corroborating cross-talk between both biosynthesis pathways. Therefore, peroxisomal localization of MEL biosynthesis is not only prerequisite for generation of the natural spectrum of MELs, but also facilitates simultaneous assembly of different glycolipids in a single cell. © 2014 John Wiley & Sons Ltd.

  5. Essential oil biosynthesis and regulation in the genus Cymbopogon.

    Science.gov (United States)

    Ganjewala, Deepak; Luthra, Rajesh

    2010-01-01

    Essential oils distilled from Cymbopogon species are of immense commercial value as flavors and fragrances in the perfumery, cosmetics, soaps, and detergents and in pharmaceutical industries. Two major constituents of the essential oil, geraniol and citral, due to their specific rose and lemon like aromas are widely used as flavors, fragrances and cosmetics. Citral is also used for the synthesis of vitamin A and ionones (for example, beta-ionone, methyl ionone). Moreover, Cymbopogon essential oils and constituents possess many useful biological activities including cytotoxic, anti-inflammatory and antioxidant. Despite the immense commercial and biological significance of the Cymbopogon essential oils, little is known about their biosynthesis and regulatory mechanisms. So far it is known that essential oils are biosynthesized via the classical acetate-MVA route and existence of a newly discovered MEP pathway in Cymbopogon remains as a topic for investigation. The aim of the present review is to discuss the biosynthesis and regulation of essential oils in the genus Cymbopogon with given emphasis to two elite members, lemongrass (C. flexuosus Nees ex Steud) and palmarosa (C. martinii Roxb.). This article highlights the work done so far towards understanding of essential oil biosynthesis and regulation in the genus Cymbopogon. Also, based on our experiences with Cymbopogon species, we would like to propose C. flexuosus as a model system for the study of essential oil metabolism beyond the much studied plant family Lamiaceae.

  6. Evaluation of Biosynthetic Pathway and Engineered Biosynthesis of Alkaloids

    Directory of Open Access Journals (Sweden)

    Shinji Kishimoto

    2016-08-01

    Full Text Available Varieties of alkaloids are known to be produced by various organisms, including bacteria, fungi and plants, as secondary metabolites that exhibit useful bioactivities. However, understanding of how those metabolites are biosynthesized still remains limited, because most of these compounds are isolated from plants and at a trace level of production. In this review, we focus on recent efforts in identifying the genes responsible for the biosynthesis of those nitrogen-containing natural products and elucidating the mechanisms involved in the biosynthetic processes. The alkaloids discussed in this review are ditryptophenaline (dimeric diketopiperazine alkaloid, saframycin (tetrahydroisoquinoline alkaloid, strictosidine (monoterpene indole alkaloid, ergotamine (ergot alkaloid and opiates (benzylisoquinoline and morphinan alkaloid. This review also discusses the engineered biosynthesis of these compounds, primarily through heterologous reconstitution of target biosynthetic pathways in suitable hosts, such as Escherichia coli, Saccharomyces cerevisiae and Aspergillus nidulans. Those heterologous biosynthetic systems can be used to confirm the functions of the isolated genes, economically scale up the production of the alkaloids for commercial distributions and engineer the biosynthetic pathways to produce valuable analogs of the alkaloids. In particular, extensive involvement of oxidation reactions catalyzed by oxidoreductases, such as cytochrome P450s, during the secondary metabolite biosynthesis is discussed in details.

  7. Lipophagy Contributes to Testosterone Biosynthesis in Male Rat Leydig Cells.

    Science.gov (United States)

    Ma, Yi; Zhou, Yan; Zhu, Yin-Ci; Wang, Si-Qi; Ping, Ping; Chen, Xiang-Feng

    2018-02-01

    In recent years, autophagy was found to regulate lipid metabolism through a process termed lipophagy. Lipophagy modulates the degradation of cholesteryl esters to free cholesterol (FC), which is the substrate of testosterone biosynthesis. However, the role of lipophagy in testosterone production is unknown. To investigate this, primary rat Leydig cells and varicocele rat models were administered to inhibit or promote autophagy, and testosterone, lipid droplets (LDs), total cholesterol (TC), and FC were evaluated. The results demonstrated that inhibiting autophagy in primary rat Leydig cells reduced testosterone production. Further studies demonstrated that inhibiting autophagy increased the number and size of LDs and the level of TC, but decreased the level of FC. Furthermore, hypoxia promoted autophagy in Leydig cells. We found that short-term hypoxia stimulated testosterone secretion; however, the inhibition of autophagy abolished stimulated testosterone release. Hypoxia decreased the number and size of LDs in Leydig cells, but the changes could be largely rescued by blocking autophagy. In experimental varicocele rat models, the administration of autophagy inhibitors substantially reduced serum testosterone. These data demonstrate that autophagy contributes to testosterone biosynthesis at least partially through degrading intracellular LDs/TC. Our observations might reveal an autophagic regulatory mode regarding testosterone biosynthesis. Copyright © 2018 Endocrine Society.

  8. Bacterial cellulose biosynthesis: diversity of operons, subunits, products and functions

    Science.gov (United States)

    Römling, Ute; Galperin, Michael Y.

    2015-01-01

    Summary Recent studies of bacterial cellulose biosynthesis, including structural characterization of a functional cellulose synthase complex, provided the first mechanistic insight into this fascinating process. In most studied bacteria, just two subunits, BcsA and BcsB, are necessary and sufficient for the formation of the polysaccharide chain in vitro. Other subunits – which differ among various taxa – affect the enzymatic activity and product yield in vivo by modulating expression of biosynthesis apparatus, export of the nascent β-D-glucan polymer to the cell surface, and the organization of cellulose fibers into a higher-order structure. These auxiliary subunits play key roles in determining the quantity and structure of the resulting biofilm, which is particularly important for interactions of bacteria with higher organisms that lead to rhizosphere colonization and modulate virulence of cellulose-producing bacterial pathogens inside and outside of host cells. Here we review the organization of four principal types of cellulose synthase operons found in various bacterial genomes, identify additional bcs genes that encode likely components of the cellulose biosynthesis and secretion machinery, and propose a unified nomenclature for these genes and subunits. We also discuss the role of cellulose as a key component of biofilms formed by a variety of free-living and pathogenic bacteria and, for the latter, in the choice between acute infection and persistence in the host. PMID:26077867

  9. Metabolic routes affecting rubber biosynthesis in Hevea brasiliensis latex

    Science.gov (United States)

    Chow, Keng-See; Mat-Isa, Mohd.-Noor; Bahari, Azlina; Ghazali, Ahmad-Kamal; Alias, Halimah; Mohd.-Zainuddin, Zainorlina; Hoh, Chee-Choong; Wan, Kiew-Lian

    2012-01-01

    The cytosolic mevalonate (MVA) pathway in Hevea brasiliensis latex is the conventionally accepted pathway which provides isopentenyl diphosphate (IPP) for cis-polyisoprene (rubber) biosynthesis. However, the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway may be an alternative source of IPP since its more recent discovery in plants. Quantitative RT-PCR (qRT-PCR) expression profiles of genes from both pathways in latex showed that subcellular compartmentalization of IPP for cis-polyisoprene synthesis is related to the degree of plastidic carotenoid synthesis. From this, the occurrence of two schemes of IPP partitioning and utilization within one species is proposed whereby the supply of IPP for cis-polyisoprene from the MEP pathway is related to carotenoid production in latex. Subsequently, a set of latex unique gene transcripts was sequenced and assembled and they were then mapped to IPP-requiring pathways. Up to eight such pathways, including cis-polyisoprene biosynthesis, were identified. Our findings on pre- and post-IPP metabolic routes form an important aspect of a pathway knowledge-driven approach to enhancing cis-polyisoprene biosynthesis in transgenic rubber trees. PMID:22162870

  10. ODORANT1 Regulates Fragrance Biosynthesis in Petunia FlowersW⃞

    Science.gov (United States)

    Verdonk, Julian C.; Haring, Michel A.; van Tunen, Arjen J.; Schuurink, Robert C.

    2005-01-01

    Floral scent is important to plant reproduction because it attracts pollinators to the sexual organs. Therefore, volatile emission is usually tuned to the foraging activity of the pollinators. In Petunia hybrida, volatile benzenoids determine the floral aroma. Although the pathways for benzenoid biosynthesis have been characterized, the enzymes involved are less well understood. How production and emission are regulated is unknown. By targeted transcriptome analyses, we identified ODORANT1 (ODO1), a member of the R2R3-type MYB family, as a candidate for the regulation of volatile benzenoids in Petunia hybrida cv W115 (Mitchell) flowers. These flowers are only fragrant in the evening and at night. Transcript levels of ODO1 increased before the onset of volatile emission and decreased when volatile emission declined. Downregulation of ODO1 in transgenic P. hybrida Mitchell plants strongly reduced volatile benzenoid levels through decreased synthesis of precursors from the shikimate pathway. The transcript levels of several genes in this pathway were reduced by suppression of ODO1 expression. Moreover, ODO1 could activate the promoter of the 5-enol-pyruvylshikimate-3-phosphate synthase gene. Flower pigmentation, which is furnished from the same shikimate precursors, was not influenced because color and scent biosynthesis occur at different developmental stages. Our studies identify ODO1 as a key regulator of floral scent biosynthesis. PMID:15805488

  11. Deconvoluting heme biosynthesis to target blood-stage malaria parasites

    Science.gov (United States)

    Sigala, Paul A; Crowley, Jan R; Henderson, Jeffrey P; Goldberg, Daniel E

    2015-01-01

    Heme metabolism is central to blood-stage infection by the malaria parasite Plasmodium falciparum. Parasites retain a heme biosynthesis pathway but do not require its activity during infection of heme-rich erythrocytes, where they can scavenge host heme to meet metabolic needs. Nevertheless, heme biosynthesis in parasite-infected erythrocytes can be potently stimulated by exogenous 5-aminolevulinic acid (ALA), resulting in accumulation of the phototoxic intermediate protoporphyrin IX (PPIX). Here we use photodynamic imaging, mass spectrometry, parasite gene disruption, and chemical probes to reveal that vestigial host enzymes in the cytoplasm of Plasmodium-infected erythrocytes contribute to ALA-stimulated heme biosynthesis and that ALA uptake depends on parasite-established permeability pathways. We show that PPIX accumulation in infected erythrocytes can be harnessed for antimalarial chemotherapy using luminol-based chemiluminescence and combinatorial stimulation by low-dose artemisinin to photoactivate PPIX to produce cytotoxic reactive oxygen. This photodynamic strategy has the advantage of exploiting host enzymes refractory to resistance-conferring mutations. DOI: http://dx.doi.org/10.7554/eLife.09143.001 PMID:26173178

  12. Plant-like biosynthesis of isoquinoline alkaloids in Aspergillus fumigatus.

    Science.gov (United States)

    Baccile, Joshua A; Spraker, Joseph E; Le, Henry H; Brandenburger, Eileen; Gomez, Christian; Bok, Jin Woo; Macheleidt, Juliane; Brakhage, Axel A; Hoffmeister, Dirk; Keller, Nancy P; Schroeder, Frank C

    2016-06-01

    Natural product discovery efforts have focused primarily on microbial biosynthetic gene clusters (BGCs) containing large multimodular polyketide synthases and nonribosomal peptide synthetases; however, sequencing of fungal genomes has revealed a vast number of BGCs containing smaller NRPS-like genes of unknown biosynthetic function. Using comparative metabolomics, we show that a BGC in the human pathogen Aspergillus fumigatus named fsq, which contains an NRPS-like gene lacking a condensation domain, produces several new isoquinoline alkaloids known as the fumisoquins. These compounds derive from carbon-carbon bond formation between two amino acid-derived moieties followed by a sequence that is directly analogous to isoquinoline alkaloid biosynthesis in plants. Fumisoquin biosynthesis requires the N-methyltransferase FsqC and the FAD-dependent oxidase FsqB, which represent functional analogs of coclaurine N-methyltransferase and berberine bridge enzyme in plants. Our results show that BGCs containing incomplete NRPS modules may reveal new biosynthetic paradigms and suggest that plant-like isoquinoline biosynthesis occurs in diverse fungi.

  13. Biosynthesis of Silver Nanoparticles Using Carum carvi Extract and its Inhibitory Effect on Growth of Candida albicans

    Directory of Open Access Journals (Sweden)

    Nasiri

    2016-08-01

    Full Text Available Background Biological synthesis of nanoparticles has emerged as a promising field of biotechnology. Various biological systems including fungi, yeasts, bacteria, and plants have been used for biosynthesis of nanoparticles. Silver nanoparticles have unique properties that make them ideal for various medical and industrial applications. Owing to high levels of organic reducing agents and ease of manipulation, plant extracts are widely used for biological generation of various types of metal nanoparticles. Objectives The objective of the present study was to evaluate efficacy of Carum carvi extract in biosynthesis of silver nanoparticles and to investigate antifungal effects of the biosynthesized nanoparticles. Methods Silver nanoparticles were synthesized by addition of silver nitrate solution into fresh extract of C. carvi. Characterization of the synthesized silver nanoparticles was performed by transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive spectrometry (EDS, and X-ray diffraction analysis (XRD. Inhibitory effect of silver nanoparticles on Candida albicans growth was evaluated by serial microdilution method. Results The results revealed the formation of spherical silver nanoparticles with an average size of 10 nm. Moreover, concentration of SNPs in a 25 mL sample containing both SNPs and plant extract biomass was 2.934 mg/L on average. Serial microdilution test showed that SNPs at the concentration of 50 μg/mL can inhibit growth of the pathogen. Conclusions The present study extends the existing literature about green synthesis of nanoparticles using plant tissues and extracts.

  14. Biosynthesis and the conjugation of magnetite nanoparticles with luteinizing hormone releasing hormone (LHRH)

    Energy Technology Data Exchange (ETDEWEB)

    Obayemi, J.D. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Department of Materials Science and Engineering, Kwara State University, Malete, Kwara State (Nigeria); Dozie-Nwachukwu, S. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Sheda Science and Technology Complex (SHESTCO) Abuja, Federal Capital Territory (Nigeria); Danyuo, Y. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Department of Electronics and Electricals Engineering, Nigerian Turkish Nile University, Abuja (Nigeria); Odusanya, O.S. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Sheda Science and Technology Complex (SHESTCO) Abuja, Federal Capital Territory (Nigeria); Anuku, N. [Department of Chemistry, Bronx Community College, New York, NY 10453 (United States); Princeton Institute of Science and Technology of Materials (PRISM), Princeton, NJ 08544 (United States); Malatesta, K. [Princeton Institute of Science and Technology of Materials (PRISM), Princeton, NJ 08544 (United States); Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544 (United States); Soboyejo, W.O., E-mail: soboyejo@princeton.edu [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Princeton Institute of Science and Technology of Materials (PRISM), Princeton, NJ 08544 (United States); Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544 (United States)

    2015-01-01

    This paper presents the results of an experimental study of the biosynthesis of magnetite nanoparticles (BMNPs) with particle sizes between 10 nm and 60 nm. The biocompatible magnetic nanoparticles are produced from Magnetospirillum magneticum (M.M.) bacteria that respond to magnetic fields. M.M. bacteria were cultured and used to synthesize magnetite nanoparticles. This was done in an enriched magnetic spirillum growth medium (EMSGM) at different pH levels. The nanoparticle concentrations were characterized with UV–Visible (UV–Vis) spectroscopy, while the particle shapes were elucidated via transmission electron microscopy (TEM). The structure of the particles was studied using X-ray diffraction (XRD), while the hydrodynamic radii, particle size distributions and polydispersity of the nanoparticles were characterized using dynamic light scattering (DLS). Carbodiimide reduction was also used to functionalize the BMNPs with a molecular recognition unit (luteinizing hormone releasing hormone, LHRH) that attaches specifically to receptors that are over-expressed on the surfaces of most breast cancer cell types. The resulting nanoparticles were examined using Fourier Transform Infrared (FTIR) spectroscopy and quantitative image analysis. The implications of the results are then discussed for the potential development of magnetic nanoparticles for the specific targeting and treatment of breast cancer. - Highlights: • Biosynthesis of MNPs with clinically relevant sizes between 10 and 60 nm. • New insights into the effects of pH and processing time on nanoparticle shapes and sizes. • Successful conjugation of biosynthesized magnetite nanoparticles to LHRH ligands. • Conjugated BMNPs that are monodispersed with potential biomedical relevance. • Magnetic properties of biosynthesized MNPs suggest potential for MRI enhancement.

  15. Biosynthesis of Silver Nanoparticles Using Oscillatoria Extract and Evaluation the Anticancer and Antibacterial Activities

    Directory of Open Access Journals (Sweden)

    T Ghasemipour

    2017-07-01

    Full Text Available Abstract Background and aim: The emergence of nanotechnology is one of the most promising areas for medical research. Today, biological methods of synthesizing nanoparticles have been considered in the fight against many diseases. The purpose of this study was to evaluate the anti-cancer and anti-bacterial activity of silver nanoparticles, biosynthesized with cyanobacteria acetate extract. Methods: In the present experimental study, the silver nanoparticles biosynthesis was performed using silver ions regeneration with cyanobacteria acetate extracts. Techniques such as X-ray diffraction, scanning electron microscopy and transient evaluation of silver nanoparticles were evaluated. In order to investigate the antibacterial activity of synthesized nanosilver, serial dilution method was used for broth microdilution test to determine minimum inhibitory concentration (MIC. The effects of silver nanoparticle toxicity on T47D breast cancer cell line were evaluated using MTT colorimetric method. Also, the proximal anxine 0.5 propidoid yodide kit and flow cytometry system were evaluated to evaluate the percentage of apoptosis and necrosis in cancer cells treated with silver nanoparticles. Results: Characterization of biosynthetic silver nanoparticles indicated that these nanoparticles had a mean size of 30 nm with dominant spherical morphology. The evaluation of the antibacterial properties of biosynthetic nanoparticles showed that the minimum inhibitory concentration for Escherichia coli, Acinetobacter Bumanni and Staphylococcus aureus was 25, 50 and 12.5 μg / ml, respectively. The results of cell proliferation of nanoparticles showed that its effect depends on the concentration and time of treatment of silver nanoparticles on cancerous cells. In addition, flow cytometric results showed an apoptotic cell death rate of 35% in the T47D cell line. Conclusion: Biosynthesis nanoparticles have anticancer and antibacterial activity and can be studied further

  16. Dithiolopyrrolones: biosynthesis, synthesis, and activity of a unique class of disulfide-containing antibiotics.

    Science.gov (United States)

    Li, Bo; Wever, Walter J; Walsh, Christopher T; Bowers, Albert A

    2014-07-01

    Covering: up to 2014. Dithiolopyrrolone (DTP) group antibiotics were first isolated in the early half of the 20th century, but only recently has research been reawakened by insights gained from the synthesis and biosynthesis of this structurally intriguing class of molecules. DTPs are characterized by an electronically unique bicyclic structure, which contains a compact disulfide bridge between two ene-thiols. Points of diversity within the compound class occur outside of the bicyclic core, at the two amide nitrogens. Such modifications distinguish three of the most well studied members of the class, holomycin, thiolutin, and aureothricin; the DTP core has also more recently been identified in the marine antibiotic thiomarinol, in which it is linked to a marinolic acid moiety, analog of the FDA-approved topical antibiotic Bactroban® (GlaxoSmithKline). Dithiolopyrrolones exhibit relatively broad-spectrum antibiotic activity against many Gram-positive and Gram-negative bacteria, as well as strains of Mycobacterium tuberculosis. Additionally, they have been shown to exhibit potent and selective anti-cancer activity. Despite this promising profile, there is still much unknown about the mechanisms of action for DTPs. Early reports suggested that they inhibit yeast growth at the level of transcription and that this effect is largely responsible for their distinctive microbial static properties; a similar mechanism is supported in bacteria. Elucidation of biosynthetic pathways for holomycin in Streptomyces clavuligerus and Yersinia ruckeri and thiomarinol in Alteromonas rava sp. nov. SANK 73390, have contributed evidence suggesting that multiple mechanisms may be operative in the activity of these compounds. This review will comprehensively cover the history and development of dithiolopyrrolones with particular emphasis on the biosynthesis, synthesis, biological activity and mechanism of action.

  17. Microorganism mediated biosynthesis of metal chalcogenides; a powerful tool to transform toxic effluents into functional nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Vena, M. Paula; Jobbágy, Matías; Bilmes, Sara A., E-mail: sarabil@qi.fcen.uba.ar

    2016-09-15

    Cadmium contained in soil and water can be taken up by certain crops and aquatic organisms and accumulate in the food-chain, thus removal of Cd from mining or industrial effluents – i.e. Ni-Cd batteries, electroplating, pigments, fertilizers – becomes mandatory for human health. In parallel, there is an increased interest in the production of luminescent Q-dots for applications in bioimaging, sensors and electronic devices, even the present synthesis methods are economic and environmentally costly. An alternative green pathway for producing Metal chalcogenides (MC: CdS, CdSe, CdTe) nanocrystals is based on the metabolic activity of living organisms. Intracellular and extracellular biosynthesis of can be achieved within a biomimetic approach feeding living organisms with Cd precursors providing new routes for combining bioremediation with green routes for producing MC nanoparticles. In this mini-review we present the state-of-the-art of biosynthesis of MC nanoparticles with a critical discussion of parameters involved and protocols. Few existing examples of scaling-up are also discussed. A modular reactor based on microorganisms entrapped in biocompatible mineral matrices – already proven for bioremediation of dissolved dyes – is proposed for combining both Cd-depletion and MC nanoparticle's production. - Highlights: • Removal of heavy metals by living matter is feasible trough biosorption and bioaccumulation • Algae, fungi, bacteria and yeasts can synthesize CdS, CdSe and CdTe Q-dots • Encapsulation of microorganisms in mineral gels provides building blocks for reactor design. • Depletion of Cd with production of Q-dots can be achieved with modular bioreactors with entrapped cells.

  18. Mineral resources

    International Nuclear Information System (INIS)

    1991-09-01

    This paper reports that to prevent the concentration of control over federal oil and gas resources in a few companies or individuals, Congress has limited the number of acres of oil and gas leases that one party may control in a single state. An exception to this limitation involves lease acreage within the boundaries of development contracts. These contracts permit oil and gas lease operators and pipeline companies to contract with enough lessees to economically justify large-scale drilling operations for the production and transportation of oil and gas, subject to approval by the Secretary of the Interior, who must find that such contracts are in the public interest. Since 1986 Interior has entered into or approved 10 contracts with 12 lease operators for exploration of largely unleased federal lands-ranging from about 180,000 to 3.5 million acres in four western states-and has designated them as developmental contracts. GAO believes that the 10 contracts do not satisfy the legal requirements for development contracts because they are for oil and gas exploration on largely unleased federal lands, rather than for developing existing leases. By designating the 10 contracts as development contracts, Interior has enabled nine of the 12 contract parties to accumulate lease acreage that vastly exceeds the statutory acreage limitation. All nine of the contract parties were major or large independent oil companies. As a result, other parties who wish to participate in developing federal oil and gas resources within the four states may be adversely affected because the parties to Interior's contracts have been able to compete for and obtain lease acreage beyond the statutory acreage limitation. Although Interior believes that the Secretary has the discretion under law to use development contracts in the current manner, in April 1989 it ceased issuing these contracts pending completion of GAO's review

  19. Biosynthesis of Cu, ZVI, and Ag nanoparticles using Dodonaea viscosa extract for antibacterial activity against human pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Kiruba Daniel, S. C. G.; Vinothini, G. [Anna University of Technology, Tiruchirappalli, Department of Nanoscience and Technology (India); Subramanian, N. [Anna University of Technology, Tiruchirappalli, Department of Pharmaceutical Technology (India); Nehru, K. [Anna University of Technology, Tiruchirappalli, Department of Chemistry (India); Sivakumar, M., E-mail: muthusiva@gmail.com [Anna University of Technology, Tiruchirappalli, Department of Nanoscience and Technology (India)

    2013-01-15

    Biosynthesis of copper, zero-valent iron (ZVI), and silver nanoparticles using leaf extract of Dodonaea viscosa has been investigated in this report. There are no additional surfactants/polymers used as capping or reducing agents for these syntheses. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, X-ray diffraction, atomic force microscopy, and high-resolution transmission electron microscopy. The phase analysis was performed using selected area electron diffraction. The pH dependence of surface plasmon resonance and subsequent size variation has been determined. The synthesized nanoparticles showed spherical morphology and the average size of 29, 27, and 16 nm for Cu, ZVI, and Ag nanoparticles, respectively. Finally, biosynthesized Cu, ZVI, and Ag nanoparticles were tested against human pathogens viz. Gram-negative Escherichia coli, Klebsiella pneumonia, Pseudomonas fluorescens and Gram-positive Staphylococcus aureus and Bacillus subtilis, and showed good antimicrobial activity.

  20. Biosynthesis of Cu, ZVI, and Ag nanoparticles using Dodonaea viscosa extract for antibacterial activity against human pathogens

    International Nuclear Information System (INIS)

    Kiruba Daniel, S. C. G.; Vinothini, G.; Subramanian, N.; Nehru, K.; Sivakumar, M.

    2013-01-01

    Biosynthesis of copper, zero-valent iron (ZVI), and silver nanoparticles using leaf extract of Dodonaea viscosa has been investigated in this report. There are no additional surfactants/polymers used as capping or reducing agents for these syntheses. The synthesized nanoparticles were characterized by UV–Vis spectroscopy, X-ray diffraction, atomic force microscopy, and high-resolution transmission electron microscopy. The phase analysis was performed using selected area electron diffraction. The pH dependence of surface plasmon resonance and subsequent size variation has been determined. The synthesized nanoparticles showed spherical morphology and the average size of 29, 27, and 16 nm for Cu, ZVI, and Ag nanoparticles, respectively. Finally, biosynthesized Cu, ZVI, and Ag nanoparticles were tested against human pathogens viz. Gram-negative Escherichia coli, Klebsiella pneumonia, Pseudomonas fluorescens and Gram-positive Staphylococcus aureus and Bacillus subtilis, and showed good antimicrobial activity.