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Sample records for economically important cyanobacterium

  1. Genomic Structure of an Economically Important Cyanobacterium, Arthrospira (Spirulina) platensis NIES-39

    PubMed Central

    Fujisawa, Takatomo; Narikawa, Rei; Okamoto, Shinobu; Ehira, Shigeki; Yoshimura, Hidehisa; Suzuki, Iwane; Masuda, Tatsuru; Mochimaru, Mari; Takaichi, Shinichi; Awai, Koichiro; Sekine, Mitsuo; Horikawa, Hiroshi; Yashiro, Isao; Omata, Seiha; Takarada, Hiromi; Katano, Yoko; Kosugi, Hiroki; Tanikawa, Satoshi; Ohmori, Kazuko; Sato, Naoki; Ikeuchi, Masahiko; Fujita, Nobuyuki; Ohmori, Masayuki

    2010-01-01

    A filamentous non-N2-fixing cyanobacterium, Arthrospira (Spirulina) platensis, is an important organism for industrial applications and as a food supply. Almost the complete genome of A. platensis NIES-39 was determined in this study. The genome structure of A. platensis is estimated to be a single, circular chromosome of 6.8 Mb, based on optical mapping. Annotation of this 6.7 Mb sequence yielded 6630 protein-coding genes as well as two sets of rRNA genes and 40 tRNA genes. Of the protein-coding genes, 78% are similar to those of other organisms; the remaining 22% are currently unknown. A total 612 kb of the genome comprise group II introns, insertion sequences and some repetitive elements. Group I introns are located in a protein-coding region. Abundant restriction-modification systems were determined. Unique features in the gene composition were noted, particularly in a large number of genes for adenylate cyclase and haemolysin-like Ca2+-binding proteins and in chemotaxis proteins. Filament-specific genes were highlighted by comparative genomic analysis. PMID:20203057

  2. [Myiases of economic importance].

    PubMed

    Touré, S M

    1994-12-01

    A simplified list of the principal Diptera capable of causing myiasis is followed by a brief presentation of the biology, lesions inflicted, and methods of treatment and control of the myiases of economic importance. Cochliomyiasis caused by Cochliomyia hominivorax is of greatest interest, in view of the damage and losses caused by this disease. A brief account of the outbreak of infestation in Libya illustrates the danger of this parasite. Other important traumatic myiases are described: that due to Chrysomya bezziana, which causes an African myiasis similar to cochliomyiasis, and those due to Lucilia cuprina and related species. Hypodermyiasis (warble fly infestation) and oestrosis (nasal bot fly infestation in sheep) still cause major economic losses in domestic animals, justifying their inclusion in control campaigns. The same applies to stomach bot flies of the family Gasterophilidae. The account of each myiasis includes notes on parasiticides which have been found to be effective. Given the rapidity with which a parasite can now be transported from one continent to another, it is important for Veterinary Services to be well-informed and vigilant.

  3. Biosafety of biotechnologically important microalgae: intrinsic suicide switch implementation in cyanobacterium Synechocystis sp. PCC 6803

    PubMed Central

    Čelešnik, Helena; Tanšek, Anja; Tahirović, Aneja; Vižintin, Angelika; Mustar, Jernej; Vidmar, Vita; Dolinar, Marko

    2016-01-01

    ABSTRACT In recent years, photosynthetic autotrophic cyanobacteria have attracted interest for biotechnological applications for sustainable production of valuable metabolites. Although biosafety issues can have a great impact on public acceptance of cyanobacterial biotechnology, biosafety of genetically modified cyanobacteria has remained largely unexplored. We set out to incorporate biocontainment systems in the model cyanobacterium Synechocystis sp. PCC 6803. Plasmid-encoded safeguards were constructed using the nonspecific nuclease NucA from Anabaena combined with different metal-ion inducible promoters. In this manner, conditional lethality was dependent on intracellular DNA degradation for regulated autokilling as well as preclusion of horizontal gene transfer. In cells carrying the suicide switch comprising the nucA gene fused to a variant of the copM promoter, efficient inducible autokilling was elicited. Parallel to nuclease-based safeguards, cyanobacterial toxin/antitoxin (TA) modules were examined in biosafety switches. Rewiring of Synechocystis TA pairs ssr1114/slr0664 and slr6101/slr6100 for conditional lethality using metal-ion responsive promoters resulted in reduced growth, rather than cell killing, suggesting cells could cope with elevated toxin levels. Overall, promoter properties and translation efficiency influenced the efficacy of biocontainment systems. Several metal-ion promoters were tested in the context of safeguards, and selected promoters, including a nrsB variant, were characterized by beta-galactosidase reporter assay. PMID:27029902

  4. The genome of Cyanothece 51142, a unicellular diazotrophic cyanobacterium important in the marine nitrogen cycle

    SciTech Connect

    Welsh, Eric A.; Liberton, Michelle L.; Stockel, Jana; Loh, Thomas; Elvitigala, Thanura R.; Wang, Chunyan; Wollam, Aye; Fulton, Robert S.; Clifton, Sandra W.; Jacobs, Jon M.; Aurora, Rajeev; Ghosh, Bijoy K.; Sherman, Louis A.; Smith, Richard D.; Wilson, Richard K.; Pakrasi, Himadri B.

    2008-09-30

    Cyanobacteria are oxygenic photosynthetic bacteria that have significant roles in global biological carbon sequestration and oxygen production. They occupy a diverse range of habitats, from open ocean, to hot springs, deserts, and arctic waters. Cyanobacteria are known as the progenitors of the chloroplasts of plants and algae, and are the simplest known organisms to exhibit circadian behavior4. Cyanothece sp. ATCC 51142 is a unicellular marine cyanobacterium capable of N2-fixation, a process that is biochemically incompatible with oxygenic photosynthesis. To resolve this problem, Cyanothece performs photosynthesis during the day and nitrogen fixation at night, thus temporally separating these processes in the same cell. The genome of Cyanothece 51142 was completely sequenced and found to contain a unique arrangement of one large circular chromosome, four small plasmids, and one linear chromosome, the first report of such a linear element in a photosynthetic bacterium. Annotation of the Cyanothece genome was aided by the use of highthroughput proteomics data, enabling the reclassification of 25% of the proteins with no informative sequence homology. Phylogenetic analysis suggests that nitrogen fixation is an ancient process that arose early in evolution and has subsequently been lost in many cyanobacterial strains. In cyanobacterial cells, the circadian clock influences numerous processes, including carbohydrate synthesis, nitrogen fixation, photosynthesis, respiration, and the cell division cycle. During a diurnal period, Cyanothece cells actively accumulate and degrade different storage inclusion bodies for the products of photosynthesis and N2-fixation. This ability to utilize metabolic compartmentalization and energy storage makes Cyanothece an ideal system for bioenergy research, as well as studies of how a unicellular organism balances multiple, often incompatible, processes in the same cell.

  5. The economic importance of Vermont's sawtimber

    Treesearch

    Joseph A. Michaels; M. Brian Stone; Paul E. Sendak; Paul E. Sendak

    1986-01-01

    This paper concentrates on the potential economic importance of Vermont's sawtimber. The timber industry employed over 9,000 workers in 1980, and the value of stumpage cut that year was worth approximately $459 million to the State's economy. Preliminary resurvey data indicate that sawtimber inventory now exceeds 14 billion board feet. Yet, sawtimber removals...

  6. The genome of Cyanothece 51142, a unicellular diazotrophic cyanobacterium important in the marine nitrogen cycle.

    PubMed

    Welsh, Eric A; Liberton, Michelle; Stöckel, Jana; Loh, Thomas; Elvitigala, Thanura; Wang, Chunyan; Wollam, Aye; Fulton, Robert S; Clifton, Sandra W; Jacobs, Jon M; Aurora, Rajeev; Ghosh, Bijoy K; Sherman, Louis A; Smith, Richard D; Wilson, Richard K; Pakrasi, Himadri B

    2008-09-30

    Unicellular cyanobacteria have recently been recognized for their contributions to nitrogen fixation in marine environments, a function previously thought to be filled mainly by filamentous cyanobacteria such as Trichodesmium. To begin a systems level analysis of the physiology of the unicellular N(2)-fixing microbes, we have sequenced to completion the genome of Cyanothece sp. ATCC 51142, the first such organism. Cyanothece 51142 performs oxygenic photosynthesis and nitrogen fixation, separating these two incompatible processes temporally within the same cell, while concomitantly accumulating metabolic products in inclusion bodies that are later mobilized as part of a robust diurnal cycle. The 5,460,377-bp Cyanothece 51142 genome has a unique arrangement of one large circular chromosome, four small plasmids, and one linear chromosome, the first report of a linear element in the genome of a photosynthetic bacterium. On the 429,701-bp linear chromosome is a cluster of genes for enzymes involved in pyruvate metabolism, suggesting an important role for the linear chromosome in fermentative processes. The annotation of the genome was significantly aided by simultaneous global proteomic studies of this organism. Compared with other nitrogen-fixing cyanobacteria, Cyanothece 51142 contains the largest intact contiguous cluster of nitrogen fixation-related genes. We discuss the implications of such an organization on the regulation of nitrogen fixation. The genome sequence provides important information regarding the ability of Cyanothece 51142 to accomplish metabolic compartmentalization and energy storage, as well as how a unicellular bacterium balances multiple, often incompatible, processes in a single cell.

  7. Economic importance of bats in agriculture

    USGS Publications Warehouse

    Boyles, Justin G.; Cryan, Paul M.; McCracken, Gary F.; Kunz, Thomas H.

    2011-01-01

    White-nose syndrome (WNS) and the increased development of wind-power facilities are threatening populations of insectivorous bats in North America. Bats are voracious predators of nocturnal insects, including many crop and forest pests. We present here analyses suggesting that loss of bats in North America could lead to agricultural losses estimated at more than $3.7 billion/year. Urgent efforts are needed to educate the public and policy-makers about the ecological and economic importance of insectivorous bats and to provide practical conservation solutions.

  8. Forests of Indiana: Their Economic Importance

    Treesearch

    Stephen Bratkovich; Joey Gallion; Earl Leatherberry; William Hoover; William Reading; Glenn Durham

    2007-01-01

    Mental images of Indiana often range from corn, soybeans, and hogs, to high school basketball. The average Hoosier has little knowledge, however, of the scope, productivity, and economic impact of Indiana's forestland. The State's best-kept secret is that its beautiful forests that draw many visitors are also economically vital to the State's economy....

  9. Beef cattle metabiomes and their relationships with economically important phenotypes

    USDA-ARS?s Scientific Manuscript database

    The selection and optimization of economically important phenotypes, i.e. feed efficiency, in cattle has long been an effort devoted to host genetics, management, and diet. Feed costs remain the largest variable cost in beef production, and consequently, the improvement of feed efficiency is of sig...

  10. [Strategic planning: an important economic action for German hospitals].

    PubMed

    Wiese, Christoph H R; Zink, Wolfgang; Russo, Sebastian G

    2011-11-01

    In medical systems, economic issues and means of action are in the course of dwindling human (physicians and nurses) and financial resources are more important. For this reason, physicians must understand basic economic principles. Only in this way, there may be medical autonomy from social systems and hospital administrators. The current work is an approach to present a model for strategic planning of an anesthesia department. For this, a "strengths", "weaknesses", "opportunities", and "threats" (SWOT) analysis is used. This display is an example of an exemplary anaesthetic department.

  11. How important are economic factors in choice of medical specialty?

    PubMed

    Thornton, James; Esposto, Fred

    2003-01-01

    An ongoing debate exists among health care researchers about the mechanism that allocates physicians across medical specialties, and appropriate policy measures to correct imbalances that may arise from time to time. Most researchers believe that choice of residency program by medical school graduates is key to understanding how physicians are distributed across specialties, but there is much disagreement about whether economic or non-economic factors are most influential in determining this choice. We undertake an empirical investigation of two potentially important economic factors: income and leisure. To do so, we specify a two way error component regression model to estimate the effects of expected earnings and available leisure time, and uncertainty of earnings and leisure, on specialty choices of medical residents. Our findings indicate that economic factors are an important influence in the specialty choice process; in particular, medical residents are attracted to specialties that offer the prospect of longer and more certain annual vacations, higher earnings, shorter residency programs, and more certain work schedules. Our results suggest that employment contracts that provide generous annual vacation time and promise regular weekly work schedules may be more effective than increased earnings in correcting the current perceived shortage of primary care physicians.

  12. The Economic Importance of Financial Literacy: Theory and Evidence

    PubMed Central

    Lusardi, Annamaria; Mitchell, Olivia S.

    2017-01-01

    This paper undertakes an assessment of a rapidly growing body of economic research on financial literacy. We start with an overview of theoretical research which casts financial knowledge as a form of investment in human capital. Endogenizing financial knowledge has important implications for welfare as well as policies intended to enhance levels of financial knowledge in the larger population. Next, we draw on recent surveys to establish how much (or how little) people know and identify the least financially savvy population subgroups. This is followed by an examination of the impact of financial literacy on economic decision-making in the United States and elsewhere. While the literature is still young, conclusions may be drawn about the effects and consequences of financial illiteracy and what works to remedy these gaps. A final section offers thoughts on what remains to be learned if researchers are to better inform theoretical and empirical models as well as public policy. PMID:28579637

  13. ECONOMIC IMPORTANCE OF THE PREVENTIVE MEASURES IN DENTISTRY

    PubMed Central

    Deljo, Emsudina; Sijercic, Zinaida; Mulaosmanovic, Amina; Musanovic, Alma; Prses, Nedim

    2016-01-01

    Introduction: Previous studies have shown that the state of oral health in the area of Podrinje Canton is really poor. Taking into account that in the last five years are implemented two projects in the municipality it is necessary to examine the impact of preventive measures in dentistry on the oral health. The research goals are: a) To evaluate the impact of continuing education and local fluoridation on the state of oral health; b) To analyze the economic importance of preventive measures. The examinees and methods: For the purpose of the research on activities of continuing education on the importance of oral health and local fluoridation of teeth and to determine the economic aspects of the application of preventive measures is tested and reviewed 900 students from fourth to ninth grade. The children were divided into three groups of 300 students in each group: a) In the first group of children is carried out continuous education about proper tooth brushing and the importance of oral hygiene and local fluoridation twice a year during the last three years, b) In the second group children carried out local fluoridation twice a year during the last three years while in the third group, there were no continuous prevention measures; c) Used is a single questionnaire for all respondents. Data obtained in this study were analyzed by descriptive and inferential statistical methods. The results and conclusions: The importance of continuing education and local fluoridation is clearly reflected in the different values DMF-index, which was the subject of research. In the first group, in which is carried out continuous education and local fluoridation value of DMF index was 2.7, in the second group with local fluorination this value was 3.56, while in the third group, in which is not implemented preventive measures, the value DMF- index was 5.93. From an economic point the preventive measures are the cheapest, most effective and the best solution in order to maintain oral

  14. Global Establishment Risk of Economically Important Fruit Fly Species (Tephritidae)

    PubMed Central

    Qin, Yujia; Paini, Dean R.; Wang, Cong; Fang, Yan; Li, Zhihong

    2015-01-01

    The global invasion of Tephritidae (fruit flies) attracts a great deal of attention in the field of plant quarantine and invasion biology because of their economic importance. Predicting which one in hundreds of potential invasive fruit fly species is most likely to establish in a region presents a significant challenge, but can be facilitated using a self organising map (SOM), which is able to analyse species associations to rank large numbers of species simultaneously with an index of establishment. A global presence/absence dataset including 180 economically significant fruit fly species in 118 countries was analysed using a SOM. We compare and contrast ranked lists from six countries selected from each continent, and also show that those countries geographically close were clustered together by the SOM analysis because they have similar fruit fly assemblages. These closely clustered countries therefore represent greater threats to each other as sources of invasive fruit fly species. Finally, we indicate how this SOM method could be utilized as an initial screen to support prioritizing fruit fly species for further research into their potential to invade a region. PMID:25588025

  15. Global establishment risk of economically important fruit fly species (Tephritidae).

    PubMed

    Qin, Yujia; Paini, Dean R; Wang, Cong; Fang, Yan; Li, Zhihong

    2015-01-01

    The global invasion of Tephritidae (fruit flies) attracts a great deal of attention in the field of plant quarantine and invasion biology because of their economic importance. Predicting which one in hundreds of potential invasive fruit fly species is most likely to establish in a region presents a significant challenge, but can be facilitated using a self organising map (SOM), which is able to analyse species associations to rank large numbers of species simultaneously with an index of establishment. A global presence/absence dataset including 180 economically significant fruit fly species in 118 countries was analysed using a SOM. We compare and contrast ranked lists from six countries selected from each continent, and also show that those countries geographically close were clustered together by the SOM analysis because they have similar fruit fly assemblages. These closely clustered countries therefore represent greater threats to each other as sources of invasive fruit fly species. Finally, we indicate how this SOM method could be utilized as an initial screen to support prioritizing fruit fly species for further research into their potential to invade a region.

  16. Histidine kinases play important roles in the perception and signal transduction of hydrogen peroxide in the cyanobacterium, Synechocystis sp. PCC 6803.

    PubMed

    Kanesaki, Yu; Yamamoto, Hiroshi; Paithoonrangsarid, Kalyanee; Shoumskaya, Maria; Suzuki, Iwane; Hayashi, Hidenori; Murata, Norio

    2007-01-01

    Oxidative stress caused by reactive oxygen species and, in particular, to hydrogen peroxide (H(2)O(2)) has a major impact on all biological systems, including plants and microorganisms. We investigated the H(2)O(2)-inducible expression of genes in the cyanobacterium Synechocystis sp. PCC 6803 using genome-wide DNA microarrays. Our systematic screening of a library of mutant lines with defects in histidine kinases (Hiks) by RNA slot-blot hybridization and DNA-microarray analysis suggested that four Hiks, namely, Hik33, Hik34, Hik16 and Hik41, are involved in the perception and transduction of H(2)O(2) signals that regulate the gene expression of 26 of the 77 H(2)O(2)-inducible genes with induction factors higher than 4.0. Among the four Hiks, Hik33 was the main contributor and was responsible for 22 of the 26 H(2)O(2)-inducible genes under the control of the Hiks. By contrast to Hik33, PerR encoding putative peroxide-sensing protein is involved in the regulation of only nine H(2)O(2)-inducible genes.

  17. Radon monitoring in sites of economical importance in Jamaica.

    PubMed

    Grant, C N; Lalor, G C; Balcázar, M

    2012-12-01

    The main task was to evaluate possible radon risk to the public and workers in four caves of economical importance. Green Grotto Cave is a large labyrinthine limestone cave, open to the tourism; kept Rn concentration in the range 30-40 Bq m(-3). Xtabil a coral limestone sea cave is part of a beach resort resulted in very low radon concentration of 10 Bq m(-3). Windsor is an intricate limestone cave system showed Rn concentration in the range 250-350 Bq m(-3). Whereas the Oxford caves, is situated in a region of high radioactivity in soil due to the bauxite mines, reached a maximum of 2592 Bq m(-3). Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Importance of Economic Evaluation in Health Care: An Indian Perspective.

    PubMed

    Dang, Amit; Likhar, Nishkarsh; Alok, Utkarsh

    2016-05-01

    Health economic studies provide information to decision makers for efficient use of available resources for maximizing health benefits. Economic evaluation is one part of health economics, and it is a tool for comparing costs and consequences of different interventions. Health technology assessment is a technique for economic evaluation that is well adapted by developed countries. The traditional classification of economic evaluation includes cost-minimization, cost-effectiveness analysis, cost-utility analysis, and cost-benefit analysis. There has been uncertainty in the conduct of such economic evaluations in India, due to some hesitancy with respect to the adoption of their guidelines. The biggest challenge in this evolutionary method is lack of understanding of methods in current use by all those involved in the provision and purchasing of health care. In some countries, different methods of economic evaluation have been adopted for decision making, most commonly to address the question of public subsidies for the purchase of medicines. There is limited evidence on the impact of health insurance on the health and economic well-being of beneficiaries in developing countries. India is currently pursuing several strategies to improve health services for its population, including investing in government-provided services as well as purchasing services from public and private providers through various schemes. Prospects for future growth and development in this field are required in India because rapid health care inflation, increasing rates of chronic conditions, aging population, and increasing technology diffusion will require greater economic efficiency into health care systems.

  19. The Economic Importance of Higher Education in Vermont.

    ERIC Educational Resources Information Center

    Vermont State Commission on Higher Education.

    The economic and social impact of the 22 colleges and universities in Vermont is summarized. Each institution used an economic impact estimating model developed by the Higher Education Planning Commission that measures short-term cash flows and expenditures, and additional surveys prepared by the project steering committee. Questionnaires from…

  20. Molecular markers for resistance against infectious diseases of economic importance

    PubMed Central

    Prajapati, B. M.; Gupta, J. P.; Pandey, D. P.; Parmar, G. A.; Chaudhari, J. D.

    2017-01-01

    Huge livestock population of India is under threat by a large number of endemic infectious (bacterial, viral, and parasitic) diseases. These diseases are associated with high rates of morbidity and mortality, particularly in exotic and crossbred cattle. Beside morbidity and mortality, economic losses by these diseases occur through reduced fertility, production losses, etc. Some of the major infectious diseases which have great economic impact on Indian dairy industries are tuberculosis (TB), Johne’s disease (JD), mastitis, tick and tick-borne diseases (TTBDs), foot and mouth disease, etc. The development of effective strategies for the assessment and control of infectious diseases requires a better understanding of pathogen biology, host immune response, and diseases pathogenesis as well as the identification of the associated biomarkers. Indigenous cattle (Bos indicus) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance in indigenous cattle is not well documented. The association studies of few of the genes associated with various diseases, namely, solute carrier family 11 member 1, Toll-like receptors 1, with TB; Caspase associated recruitment domain 15, SP110 with JD; CACNA2D1, CD14 with mastitis and interferon gamma, BoLA­-DRB3.2 alleles with TTBDs, etc., are presented. Breeding for genetic resistance is one of the promising ways to control the infectious diseases. High host resistance is the most important method for controlling such diseases, but till today no breed is total immune. Therefore, work may be undertaken under the hypothesis that the different susceptibility to these diseases are exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against infections. Achieving maximum resistance to these diseases is the ultimate goal, is technically

  1. Molecular markers for resistance against infectious diseases of economic importance.

    PubMed

    Prajapati, B M; Gupta, J P; Pandey, D P; Parmar, G A; Chaudhari, J D

    2017-01-01

    Huge livestock population of India is under threat by a large number of endemic infectious (bacterial, viral, and parasitic) diseases. These diseases are associated with high rates of morbidity and mortality, particularly in exotic and crossbred cattle. Beside morbidity and mortality, economic losses by these diseases occur through reduced fertility, production losses, etc. Some of the major infectious diseases which have great economic impact on Indian dairy industries are tuberculosis (TB), Johne's disease (JD), mastitis, tick and tick-borne diseases (TTBDs), foot and mouth disease, etc. The development of effective strategies for the assessment and control of infectious diseases requires a better understanding of pathogen biology, host immune response, and diseases pathogenesis as well as the identification of the associated biomarkers. Indigenous cattle (Bos indicus) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance in indigenous cattle is not well documented. The association studies of few of the genes associated with various diseases, namely, solute carrier family 11 member 1, Toll-like receptors 1, with TB; Caspase associated recruitment domain 15, SP110 with JD; CACNA2D1, CD14 with mastitis and interferon gamma, BoLA--DRB3.2 alleles with TTBDs, etc., are presented. Breeding for genetic resistance is one of the promising ways to control the infectious diseases. High host resistance is the most important method for controlling such diseases, but till today no breed is total immune. Therefore, work may be undertaken under the hypothesis that the different susceptibility to these diseases are exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against infections. Achieving maximum resistance to these diseases is the ultimate goal, is technically

  2. Health as an economic engine: evidence for the importance of health in economic development.

    PubMed

    Mirvis, David M; Chang, Cyril F; Cosby, Arthur

    2008-01-01

    Most discussions on the relationships between health and economic conditions have focused on the impact of differences in personal finances or national economic conditions on health. Recently, however, the role of health as an 'economic engine' has been promoted. This paradigm proposes that better health leads to economic development. Evidence from historical, national, and transnational studies have shown that improved health increases economic growth through impacts on micro- and macro-economic factors. In this review, we will summarize the evidence supporting these concepts as a basis for discussing their implications for underdeveloped regions within the United States.

  3. The Economic Importance of Human Capital in Modernization.

    ERIC Educational Resources Information Center

    Schultz, Theodore W.

    1993-01-01

    Human capital invests in new forms of physical capital, hence, human capital is key to economic progress. Lists eight attributes of human capital; for example, human capital cannot be separated from person who has it, and human capital is not visible. Human capital is necessary component when attempting to improve a person's income and welfare in…

  4. Culturally and economically important nontimber forest products of northern Maine

    Treesearch

    Michelle J. Baumflek; Marla R. Emery; Clare. Ginger

    2010-01-01

    Nontimber forest products (NTFPs) gathered for food, medicine, craft, spiritual, aesthetic, and utilitarian purposes make substantial contributions to the economic viability and cultural vitality of communities. In the St. John River watershed of northern Maine, people identifying with cultural groups including Acadian, Maliseet, Mi'kmaq, Scotch-Irish, and Swedish...

  5. The importance of economics in fire management analysis

    Treesearch

    Robert Mavsar; Armando González-Cabán; Verónica Farrera

    2010-01-01

    Wildfires are a societal problem that threatens many ecosystems, affects millions of people worldwide, and causes major ecosystem and economic impacts at local regional, national and global scales. In Europe, and especially in the Mediterranean countries (France, Greece, Italy, Portugal and Spain), wildfires continue to be a major environmental threat (Requardt et al....

  6. The Economic Importance of Human Capital in Modernization.

    ERIC Educational Resources Information Center

    Schultz, Theodore W.

    1993-01-01

    Human capital invests in new forms of physical capital, hence, human capital is key to economic progress. Lists eight attributes of human capital; for example, human capital cannot be separated from person who has it, and human capital is not visible. Human capital is necessary component when attempting to improve a person's income and welfare in…

  7. The Economic Importance of Higher Education in Vermont, 1982.

    ERIC Educational Resources Information Center

    Vermont State Dept. of Education, Montpelier.

    Benefits of Vermont's colleges and universities, and specifically the economic aspects, are identified. Employment data are presented for elementary, secondary, and higher education; manufacturing, agriculture, and eight nonmanufacturing employment fields. Higher education in Vermont has more than 15,000 full-time and part-time employees, has a…

  8. Economic importance of elk hunting in Jackson Hole, Wyoming

    USGS Publications Warehouse

    Koontz, Lynne; Loomis, John B.

    2005-01-01

    As more hunters come to an area, local businesses will purchase extra labor and supplies to meet the increase in demand for additional services. The income and employment resulting from purchases by hunter at local businesses represent the direct effects of hunter spending within the economy. In order to increase supplies to local businesses, input suppliers must also increase their purchases of inputs from other industries. The income and employment resulting from these secondary purchases by input suppliers are the indirect effects of hunter spending within the local economy. The input supplier’s new employees use their incomes to purchase goods and services. The resulting increased economic activity from new employee income is the induced effect associated with hunter spending. The indirect and induced effects are known as the secondary effects. Multipliers capture the size of the secondary effects, usually as a ratio of total effects to direct effects (Stynes, 1998). The sums of the direct and secondary effects describe the total economic impact of hunter spending in the local economy.

  9. Inbreeding depression for economically important traits of Mazandaran native fowls.

    PubMed

    Rahmanian, A; Hafezian, H; Rahimi, G H; Farhadi, A; Baneh, H

    2015-01-01

    1. The objective was to investigate inbreeding depression for some economic traits of Mazandaran native fowls using data collected from 1992 to 2012 (21 generations) using a REML 2. The mean inbreeding coefficient (F) for the whole population and dams was 4.67% and 4.12%, respectively, and most of the inbred birds (75.79%) and inbred dams (72.58%) had F < 12.5%. 3. Individual and dam inbreeding trends were 0.55% and 0.53% per year. 4. Inbreeding depression for body weight at hatch, at 8 weeks and 12 weeks of age, age at sexual maturity, weight at sexual maturity, egg weight at 1st d of laying and average egg weight at 28, 30 and 32 weeks of laying due to a 1% increase in individual inbreeding were -0.11 g, -3.1 g, -1.3 g, 0.15 d, 0.59 g, -0.05 g and -0.03 g, respectively. 5. A 1% increase in maternal inbreeding resulted in a reduction of 0.06, 0.6 and 3.6 g in body weight at hatch, 8 weeks and 12 weeks of age.

  10. The Important Role of Physics in Industry and Economic Development

    NASA Astrophysics Data System (ADS)

    Alvarado, Igor

    2012-10-01

    Good Physics requires good education. Good education translates into good Physics professionals. The process starts early with Science, Technology, Engineering and Mathematics (STEM) education programs for Middle and High-School students. Then it continues with competitive higher education programs (2 years and 4 years) at colleges and universities designed to satisfy the needs of industry and academia. The research work conducted by graduate students in Physics (and Engineering Physics) frequently translates into new discoveries and innovations that have direct impact in society (e.g. Proton Cancer Therapy). Some of the major and largest scientific experiments in the world today are physics-centered (e.g. Large Hadron Collider-LHC) that generate employment and business opportunities for thousands of scientists, academic research groups and companies from around the world. New superconducting magnets and advanced materials that have resulted from previous research in physics are commonly used in these extreme experiments. But not all physicists will end up working at these large high-energy physics experiments, universities or National Laboratories (e.g. Fermilab); industry requires new generations of (industrial) physicists in such sectors as semiconductor, energy, space, life sciences, defense and advanced manufacturing. This work presents an industry perspective about the role of Physics in economic development and the need for a collaborative Academic-Industry approach for a more effective translational research. A series of examples will be presented with emphasis in the measurement, control, diagnostics and computing capabilities needed to translate the science (physics) into innovations and practical solutions that can benefit society as a whole.

  11. Non-terrestrial resources of economic importance to earth

    NASA Technical Reports Server (NTRS)

    Lewis, John S.

    1991-01-01

    The status of research on the importation of energy and nonterrestrial materials is reviewed, and certain specific directions for new research are proposed. New technologies which are to be developed include aerobraking, in situ propellant production, mining and beneficiation of extraterresrrial minerals, nuclear power systems, electromagnetic launch, and solar thermal propulsion. Topics discussed include the system architecture for solar power satellite constellations, the return of nonterrestrial He-3 to earth for use as a clean fusion fuel, and the return to earth of platinum-group metal byproducts from processing of nonterrestrial native ferrous metals.

  12. Non-terrestrial resources of economic importance to earth

    NASA Technical Reports Server (NTRS)

    Lewis, John S.

    1991-01-01

    The status of research on the importation of energy and nonterrestrial materials is reviewed, and certain specific directions for new research are proposed. New technologies which are to be developed include aerobraking, in situ propellant production, mining and beneficiation of extraterresrrial minerals, nuclear power systems, electromagnetic launch, and solar thermal propulsion. Topics discussed include the system architecture for solar power satellite constellations, the return of nonterrestrial He-3 to earth for use as a clean fusion fuel, and the return to earth of platinum-group metal byproducts from processing of nonterrestrial native ferrous metals.

  13. Modeling The Economics Of PACS: What Is Important?

    NASA Astrophysics Data System (ADS)

    Saarinen, Allan O.; Haynor, David R.; Loop, John W.; Johnson, Linda; Russell, John; Mitchell, Kate; Nemerever, Marilyn

    1989-05-01

    Picture Archive and Communications Systems (PACS) represent a significant long term capital investment for radiology departments and hospitals. Many radiology departments want to acquire this new imaging technology, but they are still concerned about the cost of these systems. While a few studies have tried to quantify the costs and benefits of PACS, these studies have been limited in scope. The University of Washington is evaluating a Digital Imaging Network System (DINS) and PACS for the U.S. Army Medical Research and Development Command. Part of this evaluation includes developing a comprehensive cost model of PACS for one of the military's large health care facilities (a 400 bed hospital). The paper summarizes the methodology and multi-layered spreadsheet model developed at the University to forecast the costs and potential cost savings this health care facility might accrue if a hospital wide PACS is installed and film is eliminated. It also discusses the many important assumptions made in the model. A sensitivity analysis of the model is also presented. The model indicates that keeping PACS maintenance costs down is particularly critical to the cost effectiveness of PACS. That is, the film cost savings attributed to PACS can be largely offset by PACS equipment maintenance cost. The cost effectiveness of PACS will also hinge upon whether a number of intangible benefits, such as referring physician and support staff productivity gains can be attributed to PACS. This model also suggests that the pay back period for a hospital wide PACS will vary significantly dependent upon the mix of tangible versus intangible cost savings incorporated into the modeling process.

  14. Measuring socio-economic position in dietary research: is choice of socio-economic indicator important?

    PubMed

    Turrell, Gavin; Hewitt, Belinda; Patterson, Carla; Oldenburg, Brian

    2003-04-01

    To examine the association between socio-economic position (SEP) and diet, by assessing the unadjusted and simultaneously adjusted (independent) contributions of education, occupation and household income to food purchasing behaviour. The sample was randomly selected using a stratified two-stage cluster design, and the response rate was 66.4%. Data were collected by face-to-face interview. Food purchasing was examined on the basis of three composite indices that reflected a household's choice of grocery items (including meat and chicken), fruit and vegetables. Brisbane City, Australia, 2000. : Non-institutionalised residents of private dwellings located in 50 small areas (Census Collectors Districts). When shopping, respondents in lower socio-economic groups were less likely to purchase grocery foods that were high in fibre and low in fat, salt and sugar. Disadvantaged groups purchased fewer types of fresh fruits and vegetables, and less often, than their counterparts from more advantaged backgrounds. When the relationship between SEP and food purchasing was examined using each indicator separately, education and household income made an unadjusted contribution to purchasing behaviour for all three food indices; however, occupation was significantly related only with the purchase of grocery foods. When education and occupation were simultaneously adjusted for each other, the socio-economic patterning with food purchase remained largely unchanged, although the strength of the associations was attenuated. When household income was introduced into the analysis, the association between education, occupation and food purchasing behaviour was diminished or became non-significant; income, however, showed a strong, graded association with food choice. The food purchasing behaviours of socio-economically disadvantaged groups were least in accord with dietary guideline recommendations, and hence are more consistent with greater risk for the development of diet

  15. Draft Genome Sequence of Microcystis aeruginosa CACIAM 03, a Cyanobacterium Isolated from an Amazonian Freshwater Environment

    PubMed Central

    Castro, Wendel Oliveira; Lima, Alex Ranieri Jerônimo; Moraes, Pablo Henrique Gonçalves; Siqueira, Andrei Santos; Aguiar, Délia Cristina Figueira; Baraúna, Anna Rafaella Ferreira; Martins, Luisa Carício; Fuzii, Hellen Thais; de Lima, Clayton Pereira Silva; Vianez-Júnior, João Lídio Silva Gonçalves; Nunes, Márcio Roberto Teixeira; Dall'Agnol, Leonardo Teixeira

    2016-01-01

    Given its toxigenic potential, Microcystis aeruginosa is an important bloom-forming cyanobacterium. Here, we present a draft genome and annotation of the strain CACIAM 03, which was isolated from an Amazonian freshwater environment. PMID:27856592

  16. Complexity and reflexivity: two important issues for economic evaluation in health care.

    PubMed

    Lessard, Chantale

    2007-04-01

    Economic evaluations are analytic techniques to assess the relative costs and consequences of health care programmes and technologies. Their role is to provide rigorous data to inform the health care decision-making process. Economic evaluation may oversimplify complex health care decisions. These analyses often ignore important health consequences, contextual elements, relationships or other relevant modifying factors, which might not be appropriate in a multi-objective, multi-stakeholder issue. One solution would be to develop a new paradigm based on the issues of perspective and context. Complexity theory may provide a useful conceptual framework for economic evaluation in health care. Complexity thinking develops an awareness of issues including uncertainty, contextual issues, multiple perspectives, broader societal involvement, and transdisciplinarity. This points the economic evaluation field towards an accountability and epistemology based on pluralism and uncertainty, requiring new forms of lay-expert engagement and roles of lay knowledge into decision-making processes. This highlights the issue of reflexivity in economic evaluation in health care. A reflexive approach would allow economic evaluators to analyze how objective structures and subjective elements influence their practices. In return, this would point increase the integrity and reliability of economic evaluations. Reflexivity provides opportunities for critically thinking about the organization and activities of the intellectual field, and perhaps the potential of moving in new, creative directions. This paper argues for economic evaluators to have a less positivist attitude towards what is useful knowledge, and to use more imagination about the data and methodologies they use.

  17. Predictors of the Perceived Importance of Food Skills of Home Economics Teachers

    ERIC Educational Resources Information Center

    Fordyce-Voorham, Sandra P.

    2016-01-01

    Purpose: The purpose of this paper is to test an hypothesis that teachers' personal orientations toward food preparation, nutrition and environmental issues would be related to their perceived importance of food skills. Design/methodology/approach: Little research has been conducted on home economics teachers' views on the importance of the food…

  18. Predictors of the Perceived Importance of Food Skills of Home Economics Teachers

    ERIC Educational Resources Information Center

    Fordyce-Voorham, Sandra P.

    2016-01-01

    Purpose: The purpose of this paper is to test an hypothesis that teachers' personal orientations toward food preparation, nutrition and environmental issues would be related to their perceived importance of food skills. Design/methodology/approach: Little research has been conducted on home economics teachers' views on the importance of the food…

  19. [Economic determinants of the demand for importation of pharmacochemical and pharmaceutical products].

    PubMed

    Santos, Anderson Moreira Aristides Dos; Tejada, César Augusto Oviedo; Jacinto, Paulo de Andrade

    2017-09-28

    : This article analyzes the relationship between the demand for importation of pharmacochemical and pharmaceutical products and economic variables (exchange rate, import prices, and aggregate income) in Brazil, using monthly data from 1997-2014. The main results showed that increases in aggregate income and price reductions in imports have a positive and significant impact (elastic and inelastic, respectively) on imports. Exchange rate was only significant in the more aggregate model. Thus, aggregate income was a robust variable with strong impact on the importation of pharmacochemical and pharmaceutical products. The arguments in the literature that this industry's international trade deficit is related to a deficit in knowledge and technology and the current study's results provide evidence that as economic activity grows, there is a greater demand for this type of product. Additionally, if domestic production is insufficient, there is a need for imports, which can generate pressure on the trade deficit in the industry and contribute to Brazil's dependence on other countries.

  20. Unicellular cyanobacterium symbiotic with a single-celled eukaryotic alga.

    PubMed

    Thompson, Anne W; Foster, Rachel A; Krupke, Andreas; Carter, Brandon J; Musat, Niculina; Vaulot, Daniel; Kuypers, Marcel M M; Zehr, Jonathan P

    2012-09-21

    Symbioses between nitrogen (N)(2)-fixing prokaryotes and photosynthetic eukaryotes are important for nitrogen acquisition in N-limited environments. Recently, a widely distributed planktonic uncultured nitrogen-fixing cyanobacterium (UCYN-A) was found to have unprecedented genome reduction, including the lack of oxygen-evolving photosystem II and the tricarboxylic acid cycle, which suggested partnership in a symbiosis. We showed that UCYN-A has a symbiotic association with a unicellular prymnesiophyte, closely related to calcifying taxa present in the fossil record. The partnership is mutualistic, because the prymnesiophyte receives fixed N in exchange for transferring fixed carbon to UCYN-A. This unusual partnership between a cyanobacterium and a unicellular alga is a model for symbiosis and is analogous to plastid and organismal evolution, and if calcifying, may have important implications for past and present oceanic N(2) fixation.

  1. The Changing Importance of White Women's Economic Prospects for Assortative Mating

    ERIC Educational Resources Information Center

    Sweeney, Megan M.; Cancian, Maria

    2004-01-01

    Given recent changes in the labor force participation and economic standing of women, we ask whether a woman's position in the labor market has become a more important determinant of her position in the marriage market. Unlike much prior research on trends over time in assortative mating, we take an individual-level approach to the analysis and…

  2. The Economic Importance of Air Travel in High-Amenity Rural Areas

    ERIC Educational Resources Information Center

    Rasker, Ray; Gude, Patricia H.; Gude, Justin A.; van den Noort, Jeff

    2009-01-01

    The western United States offers a case study on the importance of access to large population centers and their markets, via road and air travel, for economic development. The vast distances between towns and cities in the American West can be a detriment to business, yet they also serve to attract technology and knowledge-based workers seeking to…

  3. Draft genome sequence of Erwinia tracheiphila, an economically important bacterial pathogen of cucurbits

    USDA-ARS?s Scientific Manuscript database

    Erwinia tracheiphila is one of the most economically important pathogen of cucumbers, melons, squashes, pumpkins, and gourds, in the Northeastern and Midwestern United States, yet the molecular pathology remains uninvestigated. Here we report the first draft genome sequence of an E. tracheiphila str...

  4. The Economic Importance of Air Travel in High-Amenity Rural Areas

    ERIC Educational Resources Information Center

    Rasker, Ray; Gude, Patricia H.; Gude, Justin A.; van den Noort, Jeff

    2009-01-01

    The western United States offers a case study on the importance of access to large population centers and their markets, via road and air travel, for economic development. The vast distances between towns and cities in the American West can be a detriment to business, yet they also serve to attract technology and knowledge-based workers seeking to…

  5. Flat Mites of the World interactive identification key for economically important species in the family Tenuipalpidae

    USDA-ARS?s Scientific Manuscript database

    Several flat mite species associated with fruit and crop trees, and ornamentals are commonly intercepted at U.S. ports-of-entry. These species complex are also the most complicated and part of the most diverse group in the flat mite family. Three of the most economically important species in the fa...

  6. Assessment of oil content and fatty acid composition variability in two economically important Hibiscus species.

    USDA-ARS?s Scientific Manuscript database

    The Hibiscus genus encompasses more than 300 species, but kenaf (H. cannabinus L.) and roselle (H. sabdariffa L.) are the two most economically important species within the genus. Seeds from these two Hibiscus species contain a relatively high amount of oil with two unusual fatty acids: dihydrosterc...

  7. Tropical food legumes: virus diseases of economic importance and their control.

    PubMed

    Hema, Masarapu; Sreenivasulu, Pothur; Patil, Basavaprabhu L; Kumar, P Lava; Reddy, Dodla V R

    2014-01-01

    Diverse array of food legume crops (Fabaceae: Papilionoideae) have been adopted worldwide for their protein-rich seed. Choice of legumes and their importance vary in different parts of the world. The economically important legumes are severely affected by a range of virus diseases causing significant economic losses due to reduction in grain production, poor quality seed, and costs incurred in phytosanitation and disease control. The majority of the viruses infecting legumes are vectored by insects, and several of them are also seed transmitted, thus assuming importance in the quarantine and in the epidemiology. This review is focused on the economically important viruses of soybean, groundnut, common bean, cowpea, pigeonpea, mungbean, urdbean, chickpea, pea, faba bean, and lentil and begomovirus diseases of three minor tropical food legumes (hyacinth bean, horse gram, and lima bean). Aspects included are geographic distribution, impact on crop growth and yields, virus characteristics, diagnosis of causal viruses, disease epidemiology, and options for control. Effectiveness of selection and planting with virus-free seed, phytosanitation, manipulation of crop cultural and agronomic practices, control of virus vectors and host plant resistance, and potential of transgenic resistance for legume virus disease control are discussed.

  8. Draft Genome Sequence of Erwinia tracheiphila, an Economically Important Bacterial Pathogen of Cucurbits.

    PubMed

    Shapiro, Lori R; Scully, Erin D; Roberts, Dana; Straub, Timothy J; Geib, Scott M; Park, Jihye; Stephenson, Andrew G; Salaau Rojas, Erika; Liu, Quin; Beattie, Gwyn; Gleason, Mark; De Moraes, Consuelo M; Mescher, Mark C; Fleischer, Shelby G; Kolter, Roberto; Pierce, Naomi; Zhaxybayeva, Olga

    2015-06-04

    Erwinia tracheiphila is one of the most economically important pathogens of cucumbers, melons, squashes, pumpkins, and gourds in the northeastern and midwestern United States, yet its molecular pathology remains uninvestigated. Here, we report the first draft genome sequence of an E. tracheiphila strain isolated from an infected wild gourd (Cucurbita pepo subsp. texana) plant. The genome assembly consists of 7 contigs and includes a putative plasmid and at least 20 phage and prophage elements.

  9. Draft Genome Sequence of Erwinia tracheiphila, an Economically Important Bacterial Pathogen of Cucurbits

    PubMed Central

    Scully, Erin D.; Roberts, Dana; Straub, Timothy J.; Geib, Scott M.; Park, Jihye; Stephenson, Andrew G.; Salaau Rojas, Erika; Liu, Quin; Beattie, Gwyn; Gleason, Mark; De Moraes, Consuelo M.; Mescher, Mark C.; Fleischer, Shelby G.; Kolter, Roberto; Pierce, Naomi; Zhaxybayeva, Olga

    2015-01-01

    Erwinia tracheiphila is one of the most economically important pathogens of cucumbers, melons, squashes, pumpkins, and gourds in the northeastern and midwestern United States, yet its molecular pathology remains uninvestigated. Here, we report the first draft genome sequence of an E. tracheiphila strain isolated from an infected wild gourd (Cucurbita pepo subsp. texana) plant. The genome assembly consists of 7 contigs and includes a putative plasmid and at least 20 phage and prophage elements. PMID:26044415

  10. Biology and management of economically important lepidopteran cereal stem borers in Africa.

    PubMed

    Kfir, Rami; Overholt, W A; Khan, Z R; Polaszek, A

    2002-01-01

    Cereals (maize, sorghum, millet, rice) are extremely important crops grown in Africa for human consumption. Of the various insect pests attacking cereal crops in Africa, lepidopteran stem borers are by far the most injurious. All 21 economically important stem borers of cultivated grasses in Africa are indigenous except Chilo partellus, which invaded the continent from India, and C. sacchariphagus, which has recently been found in sugarcane in Mozambique. C. partellus is competitively displacing indigenous stem borers in East and southern Africa. A parasitoid, Cotesia flavipes, was introduced from Pakistan for biological control of C. partellus and caused a 32-55% decrease in stem borer densities. This article is an attempt to summarize the status of knowledge about economically important cereal stem borers in Africa with emphasis on their distribution, pest status and yield losses, diapause, natural enemies, cultural control, host plant resistance, and biological control. Special attention is given to Busseola fusca and C. partellus, the most important pests of maize and grain sorghum.

  11. Institutional delivery in rural India: the relative importance of accessibility and economic status

    PubMed Central

    2010-01-01

    Background Skilled attendance at delivery is an important indicator in monitoring progress towards Millennium Development Goal 5 to reduce the maternal mortality ratio by three quarters between 1990 and 2015. In addition to professional attention, it is important that mothers deliver their babies in an appropriate setting, where life saving equipment and hygienic conditions can also help reduce the risk of complications that may cause death or illness to mother and child. Over the past decade interest has grown in examining influences on care-seeking behavior and this study investigates the determinants of place of delivery in rural India, with a particular focus on assessing the relative importance of community access and economic status. Methods A descriptive analysis of trends in place of delivery using data from two national representative sample surveys in 1992 and 1998 is followed by a two-level (child/mother and community) random-effects logistical regression model using the second survey to investigate the determinants. Results In this investigation of institutional care seeking for child birth in rural India, economic status emerges as a more crucial determinant than access. Economic status is also the strongest influence on the choice between a private-for-profit or public facility amongst institutional births. Conclusion Greater availability of obstetric services will not alone solve the problem of low institutional delivery rates. This is particularly true for the use of private-for-profit institutions, in which the distance to services does not have a significant adjusted effect. In the light of these findings a focus on increasing demand for existing services seems the most rational action. In particular, financial constraints need to be addressed, and results support current trials of demand side financing in India. PMID:20525393

  12. Institutional delivery in rural India: the relative importance of accessibility and economic status.

    PubMed

    Kesterton, Amy J; Cleland, John; Sloggett, Andy; Ronsmans, Carine

    2010-06-06

    Skilled attendance at delivery is an important indicator in monitoring progress towards Millennium Development Goal 5 to reduce the maternal mortality ratio by three quarters between 1990 and 2015. In addition to professional attention, it is important that mothers deliver their babies in an appropriate setting, where life saving equipment and hygienic conditions can also help reduce the risk of complications that may cause death or illness to mother and child. Over the past decade interest has grown in examining influences on care-seeking behavior and this study investigates the determinants of place of delivery in rural India, with a particular focus on assessing the relative importance of community access and economic status. A descriptive analysis of trends in place of delivery using data from two national representative sample surveys in 1992 and 1998 is followed by a two-level (child/mother and community) random-effects logistical regression model using the second survey to investigate the determinants. In this investigation of institutional care seeking for child birth in rural India, economic status emerges as a more crucial determinant than access. Economic status is also the strongest influence on the choice between a private-for-profit or public facility amongst institutional births. Greater availability of obstetric services will not alone solve the problem of low institutional delivery rates. This is particularly true for the use of private-for-profit institutions, in which the distance to services does not have a significant adjusted effect. In the light of these findings a focus on increasing demand for existing services seems the most rational action. In particular, financial constraints need to be addressed, and results support current trials of demand side financing in India.

  13. [Use of geographical information systems in parasitic diseases and the importance of animal health economics].

    PubMed

    Ciçek, Hasan; Ciçek, Hatice; Senkul, Cetin; Tandoğan, Murat

    2008-01-01

    In the world, economical losses due to the parasitic diseases reach enormous ratios in animal production. Both developed and developing countries set aside a considerable budget to control these parasitic diseases. This situation aids in the improvement of control methods of parasitic diseases. Also, it causes new ways of investigation that includes observation, evaluation and prevention of parasitic diseases. The Geographical Information System (GIS) has recently become one of the most common methods utilized to provide disease information technology with computer supported technology in many countries. The most important qualities of GIS are the formation of a powerful database, continual updating and rapid provision of coordination related to units. Many factors are evaluated at the same time by the system and also, results from analysis of data related to disease and their causes could reduce or prevent economical losses due to parasitic disease. In this study, possible uses of Geographical Information Systems against parasitic diseases and an approach in terms of animal health economics were presented.

  14. Olfactory responses of medically and economically important mites (Acari: Epidermoptidae and Acaridae) to volatile chemicals.

    PubMed

    Skelton, A C; Birkett, M A; Pickett, J A; Cameron, M M

    2007-03-01

    Dermatophagoides farinae Hughes (Acari: Epidermoptidae), the American house dust mite, and Tyrophagus putrescentiae (Schrank) (Acari: Acaridae), the mold mite, are medically and economically important but controlling them has proved difficult, and recolonization is commonplace. Their behavioral responses to different sources of volatile chemicals are still not fully elucidated. For the first time, the Y-tube olfactometer, which is an enclosed bioassay to resolve responses to test and control volatiles, has been successfully used with these mites. Mites were tested individually, and both T. putrescentiae and D. farinae responded to food volatiles. Y-tube olfactometers may be used to test for potential semiochemicals, thereby increasing knowledge of our behavior of astigmatic mites.

  15. Microsatellite primers in luohanguo (Siraitia grosvenorii, Cucurbitaceae), an economically important plant species.

    PubMed

    Wang, Yaofang; Zhang, Qiwei; Lin, Yanfang; Li, Boling; Tang, Shaoqing

    2011-11-01

    Microsatellite markers were developed in an economically important plant, Siraitia grosvenorii, to evaluate its genetic diversity. Using the combined biotin capture method, 15 microsatellite primer sets were isolated and characterized. All of these markers showed polymorphism, and the number of alleles per locus ranged from two to 12 across 98 individuals from cultivars and a wild population. The observed and expected heterozygosities ranged from 0.000 to 0.905 and from 0.000 to 0.845, respectively. These markers will facilitate the breeding and further study of the genetic diversity of S. grosvenorii.

  16. Farmers' breeding practices and traits of economic importance for indigenous chicken in RWANDA.

    PubMed

    Mahoro, J; Muasya, T K; Mbuza, F; Mbuthia, J; Kahi, A K

    2017-09-26

    Data on breeding practices and traits of economic importance for the indigenous chicken (IC) were collected through personal interviews using structured questionnaires and direct observations of chicken management practices. The study was conducted from November 2015 to January 2016 in Rwamagana, Rulindo, Ruhango, Kicukiro and Muhanga districts of Rwanda. Data were collected and analysed through computation of indices, which represented a weighted average of all rankings of a specific trait. Spearman's non-parametric rank correlation was calculated for ranking of traits of economic importance to indicate the directional effects. The results on chicken ecotypes and their attributes showed that prolificacy, mature weight, disease tolerance, egg number and heat tolerance were highly preferred. The dwarf ecotype was most abundantly reared (38.84%) and considered to be significantly smaller and to have poorer growth rate, but to have better prolificacy than other indigenous chicken ecotypes. Selection of breeding cock and hen was based on disease tolerance, body weight at sexual maturity, body size and growth rate. In addition, for hen, mothering ability and egg fertility (Fer) were considered. Indices for the traits perceived by farmers as of primary economic importance were egg yield (0.093), disease tolerance (0.091), high growth rate (0.089), prolificacy (0.088), high body weight (0.087) and egg fertility (0.083). The most important traits considered by the marketers were body weight (BW), disease tolerance (Dtol), plumage colour (Pcol), egg yolk colour (EYC), meat quality (MQ), growth rate (GR) and egg yield (EY) whereas for consumers, meat quality, egg yolk colour, egg yield, body weight and growth rate were considered. Among traits perceived as important by farmers, a positive and significant correlation was found between BW and GR and Fer. Correlation was moderate for BW and prolificacy, drought tolerance (Drtol), Dtol and EYC. BW was negatively correlated with

  17. West European economic security and international natural gas trade: optimal portfolios of gas imports

    SciTech Connect

    Greer, B.I.

    1985-01-01

    In 1981 the dependence of Western Europe on the Soviet Union for natural gas imports became a major issue in the debate over the European involvement in the Urengoi natural gas project. This analysis addresses the question spawned by this debate: how should West Europe diversify its natural gas imports to achieve the greatest security for its economy. The analysis presents a summary of the policy and institutional background of this Western European gas market, explains the nature of European gas markets, and establishes the relationship, between contract structure and economic vulnerability. By characterizing Western Europe's gas import problem as a portfolio decision, the analysis develops a simple static model that articulates the relationship between the cost of gas imports and commensurate risk. Using the portfolio framework, the analysis develops a dynamic model to characterize the intertemporal tradeoffs that are characteristic of a depletable resource in the optimal portfolio selection. An optimal control formulation provides insights that generalize the static portfolio model. Both the static and dynamic formulations provide the basis of computational models that produce empirical estimates of optimal natural gas import portfolios for Western Europe.

  18. Photosynthetic production of glycerol by a recombinant cyanobacterium.

    PubMed

    Savakis, Philipp; Tan, Xiaoming; Du, Wei; Branco dos Santos, Filipe; Lu, Xuefeng; Hellingwerf, Klaas J

    2015-02-10

    Cyanobacteria are prokaryotic organisms capable of oxygenic photosynthesis. Glycerol is an important commodity chemical. Introduction of phosphoglycerol phosphatase 2 from Saccharomyces cerevisiae into the model cyanobacterium Synechocystis sp. PCC6803 resulted in a mutant strain that produced a considerable amount of glycerol from light, water and COPhotosynthetic production . Mild salt stress (200 mM NaCl) on the cells led to an increase of the extracellular glycerol concentration of more than 20%. Under these conditions the mutant accumulated glycerol to an extracellular concentration of 14.3 mM after 17 days of culturing.

  19. Economically and ecologically important plant communities in high altitude coniferous forest of Malam Jabba, Swat, Pakistan.

    PubMed

    Sher, Hassan; Al Yemeni, Mohammad

    2011-01-01

    A study on the economically important plant communities was carried out during summer 2008 in various parts of Malam Jabba valley, Swat. The principal aim of the study was phytosociological evaluation with special reference to the occurrence of commercially important medicinal plant species in coniferous forest of the study area. Secondly to prepare ethnobotanical inventory of the plant resources of the area, as well as to evaluate the conservation status of important medicinal and aromatic plants (MAPs) through rapid vulnerable assessment (RVA) procedure. The study documented 90 species of ethnobotanical importance, out of these 71 spp used as medicinal plant, 20 spp fodder plant, 10 spp vegetables, 14 spp wild fruit, 18 spp fuel wood, 9 spp furniture and agricultural tools, 9 spp thatching, fencing and hedges, 4 spp honey bee, 2 spp evil eyes, 2 spp religious and 3 spp as poison. Phytosociologically six plant communities were found, comprising five herbs-shrubs-trees communities and one meadow community. Further study is, therefore, required to quantify the availability of species and to suggest suitable method for their production and conservation. Recommendations are also given in the spheres of training in identification, sustainable collection, value addition, trade monitoring and cooperative system of marketing.

  20. Economically and ecologically important plant communities in high altitude coniferous forest of Malam Jabba, Swat, Pakistan

    PubMed Central

    Sher, Hassan; Al_yemeni, Mohammad

    2010-01-01

    A study on the economically important plant communities was carried out during summer 2008 in various parts of Malam Jabba valley, Swat. The principal aim of the study was phytosociological evaluation with special reference to the occurrence of commercially important medicinal plant species in coniferous forest of the study area. Secondly to prepare ethnobotanical inventory of the plant resources of the area, as well as to evaluate the conservation status of important medicinal and aromatic plants (MAPs) through rapid vulnerable assessment (RVA) procedure. The study documented 90 species of ethnobotanical importance, out of these 71 spp used as medicinal plant, 20 spp fodder plant, 10 spp vegetables, 14 spp wild fruit, 18 spp fuel wood, 9 spp furniture and agricultural tools, 9 spp thatching, fencing and hedges, 4 spp honey bee, 2 spp evil eyes, 2 spp religious and 3 spp as poison. Phytosociologically six plant communities were found, comprising five herbs-shrubs-trees communities and one meadow community. Further study is, therefore, required to quantify the availability of species and to suggest suitable method for their production and conservation. Recommendations are also given in the spheres of training in identification, sustainable collection, value addition, trade monitoring and cooperative system of marketing. PMID:23961104

  1. Understanding United States Investigational Device Exemption Studies-Clinical Relevance and Importance for Healthcare Economics.

    PubMed

    Ament, Jared D; Mollan, Scott; Greenan, Krista; Binyamin, Tamar; Kim, Kee D

    2017-06-01

    The US Food and Drug Administration allows a previously unapproved device to be used clinically to collect safety and effectiveness data under their Investigational Device Exemption (IDE) category. The process usually falls under 3 different trial categories: noninferiority, equivalency, and superiority. To confidently inform our patients, understanding the basic concepts of these trials is paramount. The purpose of this manuscript was to provide a comprehensive review of these topics using recently published IDE trials and economic analyses of cervical total disc replacement as illustrative examples. In 2006, an IDE was initiated to study the safety and effectiveness of total disc replacement controlled against the standard of care, anterior cervical discectomy, and fusion. Under the IDE, randomized controlled trials comparing both 1 and 2 level cervical disease were completed. The sponsor designed the initial trial as noninferiority; however, using adaptive methodology, superiority could be claimed in the 2-level investigation. Healthcare economics are critical in medical decision making and reimbursement practices. Once both cost- and quality-adjusted life-year (QALY) are known for each patient, the incremental cost-effectiveness ratio is calculated. Willingness-to-pay is controversial, but a commonly cited guideline considers interventions costing below 20 000 $/QALY strongly cost effective and more than 100 000 $/QALY as not cost effective. While large Food and Drug Administration IDE studies are often besieged by complex statistical considerations and calculations, it is fundamentally important that clinicians understand at least the terminology and basic concepts on a practical level.

  2. Gram-Negative Marine Bacteria: Structural Features of Lipopolysaccharides and Their Relevance for Economically Important Diseases

    PubMed Central

    Anwar, Muhammad Ayaz; Choi, Sangdun

    2014-01-01

    Gram-negative marine bacteria can thrive in harsh oceanic conditions, partly because of the structural diversity of the cell wall and its components, particularly lipopolysaccharide (LPS). LPS is composed of three main parts, an O-antigen, lipid A, and a core region, all of which display immense structural variations among different bacterial species. These components not only provide cell integrity but also elicit an immune response in the host, which ranges from other marine organisms to humans. Toll-like receptor 4 and its homologs are the dedicated receptors that detect LPS and trigger the immune system to respond, often causing a wide variety of inflammatory diseases and even death. This review describes the structural organization of selected LPSes and their association with economically important diseases in marine organisms. In addition, the potential therapeutic use of LPS as an immune adjuvant in different diseases is highlighted. PMID:24796306

  3. Gram-negative marine bacteria: structural features of lipopolysaccharides and their relevance for economically important diseases.

    PubMed

    Anwar, Muhammad Ayaz; Choi, Sangdun

    2014-04-30

    Gram-negative marine bacteria can thrive in harsh oceanic conditions, partly because of the structural diversity of the cell wall and its components, particularly lipopolysaccharide (LPS). LPS is composed of three main parts, an O-antigen, lipid A, and a core region, all of which display immense structural variations among different bacterial species. These components not only provide cell integrity but also elicit an immune response in the host, which ranges from other marine organisms to humans. Toll-like receptor 4 and its homologs are the dedicated receptors that detect LPS and trigger the immune system to respond, often causing a wide variety of inflammatory diseases and even death. This review describes the structural organization of selected LPSes and their association with economically important diseases in marine organisms. In addition, the potential therapeutic use of LPS as an immune adjuvant in different diseases is highlighted.

  4. Draft Genome Sequence of the Thermotolerant Cyanobacterium Desertifilum sp. IPPAS B-1220

    PubMed Central

    Sinetova, Maria A.; Bolatkhan, Kenzhegul; Zayadan, Bolatkhan K.; Ustinova, Vera V.; Kupriyanova, Elena V.; Skrypnik, Alexandra N.; Gogoleva, Natalya E.; Gogolev, Yuriy V.; Los, Dmitry A.

    2016-01-01

    Here, we report the draft genome of the filamentous cyanobacterium Desertifilum sp. strain IPPAS B-1220, isolated from Lake Shar-Nuur, Mongolia. The genome of 6.1 Mb codes for 5,113 genes. Genome mining revealed 10 clusters for the synthesis of bioactive compounds (nonribosomal peptides, polyketides, bacteriocins, and lantipeptides) with potential biotechnological or medical importance. PMID:27856594

  5. Hospital-physician relations: the relative importance of economic, relational and professional attributes to organizational attractiveness

    PubMed Central

    2014-01-01

    Background Belgian hospitals face a growing shortage of physicians and increasingly competitive market conditions. In this challenging environment hospitals are struggling to build effective hospital-physician relationships which are considered to be a critical determinant of organizational success. Methods Employed physicians of a University hospital were surveyed. Organizational attributes were identified through the literature and two focus groups. Variables were measured using validated questionnaires. Descriptive analyses and linear regression were used to test the model and relative importance analyses were performed. Results The selected attributes predict hospital attractiveness significantly (79.3%). The relative importance analysis revealed that hospital attractiveness is most strongly predicted by professional attributes (35.3%) and relational attributes (29.7%). In particular, professional development opportunities (18.8%), hospital prestige (16.5%), organizational support (17.2%) and leader support (9.3%) were found to be most important. Besides these non-economic aspects, the employed physicians indicated pay and financial benefits (7.4%) as a significant predictor of hospital attractiveness. Work-life balance and job security were not significantly related to hospital attractiveness. Conclusions This study shows that initiatives aimed at strengthening physicians’ positive perceptions of professional and relational aspects of practicing medicine in hospitals, while assuring satisfactory financial conditions, may offer useful avenues for increasing the level of perceived hospital attractiveness. Overall, hospitals are advised to use a differentiated approach to increase their attractiveness to physicians. PMID:24884491

  6. Hospital-physician relations: the relative importance of economic, relational and professional attributes to organizational attractiveness.

    PubMed

    Trybou, Jeroen; Gemmel, Paul; Van Vaerenbergh, Yves; Annemans, Lieven

    2014-05-21

    Belgian hospitals face a growing shortage of physicians and increasingly competitive market conditions. In this challenging environment hospitals are struggling to build effective hospital-physician relationships which are considered to be a critical determinant of organizational success. Employed physicians of a University hospital were surveyed. Organizational attributes were identified through the literature and two focus groups. Variables were measured using validated questionnaires. Descriptive analyses and linear regression were used to test the model and relative importance analyses were performed. The selected attributes predict hospital attractiveness significantly (79.3%). The relative importance analysis revealed that hospital attractiveness is most strongly predicted by professional attributes (35.3%) and relational attributes (29.7%). In particular, professional development opportunities (18.8%), hospital prestige (16.5%), organizational support (17.2%) and leader support (9.3%) were found to be most important. Besides these non-economic aspects, the employed physicians indicated pay and financial benefits (7.4%) as a significant predictor of hospital attractiveness. Work-life balance and job security were not significantly related to hospital attractiveness. This study shows that initiatives aimed at strengthening physicians' positive perceptions of professional and relational aspects of practicing medicine in hospitals, while assuring satisfactory financial conditions, may offer useful avenues for increasing the level of perceived hospital attractiveness. Overall, hospitals are advised to use a differentiated approach to increase their attractiveness to physicians.

  7. Insights into the Importance of Economic Concepts to Other Introductory Business Courses

    ERIC Educational Resources Information Center

    Prenshaw, Penelope J.; Taylor, Susan Washburn

    2007-01-01

    Economics is a building block for additional business knowledge. In most business curricula, the principles of economics sequence is a prerequisite for further business study. Economists have their own ideas of which economic concepts are most valued by business peers, but the authors are unaware of any published study which specifically asks…

  8. Insights into the Importance of Economic Concepts to Other Introductory Business Courses

    ERIC Educational Resources Information Center

    Prenshaw, Penelope J.; Taylor, Susan Washburn

    2007-01-01

    Economics is a building block for additional business knowledge. In most business curricula, the principles of economics sequence is a prerequisite for further business study. Economists have their own ideas of which economic concepts are most valued by business peers, but the authors are unaware of any published study which specifically asks…

  9. 77 FR 76071 - The Economic Effects of Significant U.S. Import Restraints: Eighth Update Special Topic: Services...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-26

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION The Economic Effects of Significant U.S. Import Restraints: Eighth Update Special Topic: Services' Contribution to Manufacturing AGENCY: United States International Trade Commission. ACTION: Notice of...

  10. Relative importance of climatic, geographic and socio-economic determinants of malaria in Malawi

    PubMed Central

    2013-01-01

    Background Malaria transmission is influenced by variations in meteorological conditions, which impact the biology of the parasite and its vector, but also socio-economic conditions, such as levels of urbanization, poverty and education, which impact human vulnerability and vector habitat. The many potential drivers of malaria, both extrinsic, such as climate, and intrinsic, such as population immunity are often difficult to disentangle. This presents a challenge for the modelling of malaria risk in space and time. Methods A statistical mixed model framework is proposed to model malaria risk at the district level in Malawi, using an age-stratified spatio-temporal dataset of malaria cases from July 2004 to June 2011. Several climatic, geographic and socio-economic factors thought to influence malaria incidence were tested in an exploratory model. In order to account for the unobserved confounding factors that influence malaria, which are not accounted for using measured covariates, a generalized linear mixed model was adopted, which included structured and unstructured spatial and temporal random effects. A hierarchical Bayesian framework using Markov chain Monte Carlo simulation was used for model fitting and prediction. Results Using a stepwise model selection procedure, several explanatory variables were identified to have significant associations with malaria including climatic, cartographic and socio-economic data. Once intervention variations, unobserved confounding factors and spatial correlation were considered in a Bayesian framework, a final model emerged with statistically significant predictor variables limited to average precipitation (quadratic relation) and average temperature during the three months previous to the month of interest. Conclusions When modelling malaria risk in Malawi it is important to account for spatial and temporal heterogeneity and correlation between districts. Once observed and unobserved confounding factors are allowed for

  11. Relative importance of climatic, geographic and socio-economic determinants of malaria in Malawi.

    PubMed

    Lowe, Rachel; Chirombo, James; Tompkins, Adrian M

    2013-11-14

    Malaria transmission is influenced by variations in meteorological conditions, which impact the biology of the parasite and its vector, but also socio-economic conditions, such as levels of urbanization, poverty and education, which impact human vulnerability and vector habitat. The many potential drivers of malaria, both extrinsic, such as climate, and intrinsic, such as population immunity are often difficult to disentangle. This presents a challenge for the modelling of malaria risk in space and time. A statistical mixed model framework is proposed to model malaria risk at the district level in Malawi, using an age-stratified spatio-temporal dataset of malaria cases from July 2004 to June 2011. Several climatic, geographic and socio-economic factors thought to influence malaria incidence were tested in an exploratory model. In order to account for the unobserved confounding factors that influence malaria, which are not accounted for using measured covariates, a generalized linear mixed model was adopted, which included structured and unstructured spatial and temporal random effects. A hierarchical Bayesian framework using Markov chain Monte Carlo simulation was used for model fitting and prediction. Using a stepwise model selection procedure, several explanatory variables were identified to have significant associations with malaria including climatic, cartographic and socio-economic data. Once intervention variations, unobserved confounding factors and spatial correlation were considered in a Bayesian framework, a final model emerged with statistically significant predictor variables limited to average precipitation (quadratic relation) and average temperature during the three months previous to the month of interest. When modelling malaria risk in Malawi it is important to account for spatial and temporal heterogeneity and correlation between districts. Once observed and unobserved confounding factors are allowed for, precipitation and temperature in the

  12. Emerging phytopathogen Macrophomina phaseolina: biology, economic importance and current diagnostic trends.

    PubMed

    Kaur, Surinder; Dhillon, Gurpreet Singh; Brar, Satinder Kaur; Vallad, Gary Edward; Chand, Ramesh; Chauhan, Vijay Bahadur

    2012-05-01

    Macrophomina phaseolina (Tassi) Goid. is an important phytopathogenic fungus, infecting a large number of plant species and surviving for up to 15 years in the soil as a saprophyte. Although considerable research related to the biology and ecology of Macrophomina has been conducted, it continues to cause huge economic losses in many crops. Research is needed to improve the identification and characterization of genetic variability within their epidemiological and pathological niches. Better understanding of the variability within the pathogen population for traits that influence fitness and soil survival will certainly lead to improved management strategies for Macrophomina. In this context, the present review discusses various biological aspects and distribution of M. phaseolina throughout the world and their importance to different plant species. Accurate identification of the fungus has been aided with the use of nucleic acid-based molecular techniques. The development of PCR-based methods for identification and detection of M. phaseolina are highly sensitive and specific. Early diagnosis and accurate detection of pathogens is an essential step in plant disease management as well as quarantine. The progress in the development of various molecular tools used for the detection, identification and characterization of Macrophomina isolates were also discussed.

  13. The social, economic, and environmental importance of inland fish and fisheries

    USGS Publications Warehouse

    Lynch, Abigail J.; Cooke, Steven J.; Deines, Andrew M.; Bower, Shannon D.; Bunnell, David B.; Cowx, Ian G.; Nguyen, Vivian M.; Nohner, Joel K.; Phouthavong, Kaviphone; Riley, Betsy; Rogers, Mark W.; Taylor, William W.; Woelmer, Whitney; Youn, So-Jung; Beard, T. Douglas

    2016-01-01

    Though reported capture fisheries are dominated by marine production, inland fish and fisheries make substantial contributions to meeting the challenges faced by individuals, society, and the environment in a changing global landscape. Inland capture fisheries and aquaculture contribute over 40% to the world’s reported finfish production from less than 0.01% of the total volume of water on earth. These fisheries provide food for billions and livelihoods for millions of people worldwide. Herein, using supporting evidence from the literature, we review 10 reasons why inland fish and fisheries are important to the individual (food security, economic security, empowerment), to society (cultural services, recreational services, human health and well-being, knowledge transfer and capacity building), and to the environment (ecosystem function and biodiversity, as aquatic “canaries”, the “green food” movement). However, the current limitations to valuing the services provided by inland fish and fisheries make comparison with other water resource users extremely difficult. This list can serve to demonstrate the importance of inland fish and fisheries, a necessary first step to better incorporating them into agriculture, land-use, and water resource planning, where they are currently often underappreciated or ignored.

  14. The importance of eating rice: changing food habits among pregnant Indonesian women during the economic crisis.

    PubMed

    Hartini, T Ninuk S; Padmawati, R Siwi; Lindholm, Lars; Surjono, Achmad; Winkvist, Anna

    2005-07-01

    This article presents qualitative and quantitative research findings on food habits of pregnant Indonesian women in relation to the economic crisis that arose in 1997. Between 1996 and 1998, dietary intakes were estimated for 450 pregnant women in Central Java. Between January and June 1999, four focus group discussions, 16 in-depth interviews and four non-participant observations were held with women, two in-depth interviews were held with traditional birth attendants, and four with midwives. Women were categorized as urban or rural, rich or poor, and according to rice field ownership. The women reported that before the crisis they bought more foods and cooked more meals and snacks. During the crisis, cooking methods became simpler and cooking tasty foods was more important than cooking nutritious foods. This involved using plenty of spices and cooking oil, but reducing the use of expensive nutritious foods. The herbal drink jamu was drunk by 15% of pregnant women; its consumption was lower during than before the economic crisis. Twenty-six percent of the women avoided certain foods due to food taboos, and most of these women avoided beneficial foods; this phenomenon decreased during the crisis among the rich and the rural, poor, landless women. In spite of increased prices for rice, women did not decrease their rice consumption during the crisis because rice was believed to have the highest value for survival, to provide strength during pregnancy and delivery, and to be easier to store and cook. Finally, children and husbands had highest priority in being served food, and women were the last to eat.

  15. Importance of using roller compacted concrete in techno-economic investigation and design of small dams

    NASA Astrophysics Data System (ADS)

    Rouissat, Bouchrit; Smail, N.; Zenagui, S.

    2017-07-01

    In recent years, and under constraints caused by persistent drought, Algeria has launched a new mobilization strategy for surface water resources from small and medium dams. However, by making a review of the studies and achievements of twenty small dams in the west of Algeria, some deficiencies appeared. In addition to reservoir siltation assessment, operation spillways have been the major constraint on the reliability of these types of dams. The objective of this paper is to use the roller compacted concrete (RCC) for small dams' design for the benefit it offers and its ability to incorporate spillways. The development of this reflection was applied to the Khneg Azir earth dam situated in southwest of Algeria. Its uncontrolled lateral spillway has registered significant damage following the flood of October 2005, amounted, at that time, to more than 100 million Algerian dinars (1 million US Dollars). The present research encompasses a technical and economical comparative analysis concerning multiple criteria dam design types coupled with the conjugation of the spillways. Thus, on the basis of financial estimates calculated for all design types, the variant RCC remains competitive with that of the earth dam's spillway isolated (Less than 40% of the cost). To assess the mechanical behavior of the foundations for both types of dams, (earth and RCC dams), numerical modeling has been undertaken, according to the comparative analysis of deformations in the foundations. Analysis of deformations showed that the average foundation deformations was between (0.052-0.85) m for earth dam and (0.023-0.373) m for RCC dam. These economical and technical considerations open up important prospects for the use of RCC in the design of small dams.

  16. Chlorophyll f-driven photosynthesis in a cavernous cyanobacterium.

    PubMed

    Behrendt, Lars; Brejnrod, Asker; Schliep, Martin; Sørensen, Søren J; Larkum, Anthony W D; Kühl, Michael

    2015-09-01

    Chlorophyll (Chl) f is the most recently discovered chlorophyll and has only been found in cyanobacteria from wet environments. Although its structure and biophysical properties are resolved, the importance of Chl f as an accessory pigment in photosynthesis remains unresolved. We found Chl f in a cyanobacterium enriched from a cavernous environment and report the first example of Chl f-supported oxygenic photosynthesis in cyanobacteria from such habitats. Pigment extraction, hyperspectral microscopy and transmission electron microscopy demonstrated the presence of Chl a and f in unicellular cyanobacteria found in enrichment cultures. Amplicon sequencing indicated that all oxygenic phototrophs were related to KC1, a Chl f-containing cyanobacterium previously isolated from an aquatic environment. Microsensor measurements on aggregates demonstrated oxygenic photosynthesis at 742 nm and less efficient photosynthesis under 768- and 777-nm light probably because of diminished overlap with the absorption spectrum of Chl f and other far-red absorbing pigments. Our findings suggest the importance of Chl f-containing cyanobacteria in terrestrial habitats.

  17. Genetic manipulation of a cyanobacterium for heavy metal detoxivication

    SciTech Connect

    McCormick, P.; Cannon, G.; Heinhorst, S.

    1995-12-31

    Increasing heavy metal contamination of soil and water has produced a need for economical and effective methods to reduce toxic buildup of these materials. Biological systems use metallothionein proteins to sequester such metals as Cu, Cd, and Zn. Studies are underway to genetically engineer a cyanobacteria strain with increased ability for metallothionein production and increased sequestration capacity. Cyanobacteria require only sunlight and CO{sub 2}. Vector constructs are being developed in a naturally competent, unicellular cyanobacterium Anacystis nidulans R2. Closed copies of a yeast copper metallothionein gene have been inserted into a cyanobacterial shuttle vector as well as a vector designed for genomic integration. Transformation studies have produced recombinant cyanobacteria from both of these systems, and work is currently underway to assess the organism`s ability to withstand increasing Cu, Cd, and Zn concentrations.

  18. Phylogeny of economically important insect pests that infesting several crops species in Malaysia

    NASA Astrophysics Data System (ADS)

    Ghazali, Siti Zafirah; Zain, Badrul Munir Md.; Yaakop, Salmah

    2014-09-01

    This paper reported molecular data on insect pests of commercial crops in Peninsular Malaysia. Fifteen insect pests (Metisa plana, Calliteara horsefeldii, Cotesia vestalis, Bactrocera papayae, Bactrocera carambolae, Bactrocera latifrons, Conopomorpha cramella, Sesamia inferens, Chilo polychrysa, Rhynchophorus vulneratus, and Rhynchophorus ferrugineus) of nine crops were sampled (oil palm, coconut, paddy, cocoa, starfruit, angled loofah, guava, chili and mustard) and also four species that belong to the fern's pest (Herpetogramma platycapna) and storage and rice pests (Tribolium castaneum, Oryzaephilus surinamensis and Cadra cautella). The presented phylogeny summarized the initial phylogenetic hypothesis, which concerning by implementation of the economically important insect pests. In this paper, phylogenetic relationships among 39 individuals of 15 species that belonging to three orders under 12 genera were inferred from DNA sequences of mitochondrial marker, cytochrome oxidase subunit I (COI) and nuclear marker, ribosomal DNA 28S D2 region. The phylogenies resulted from the phylogenetic analyses of both genes are relatively similar, but differ in the sequence of evolution. Interestingly, this most recent molecular data of COI sequences data by using Bayesian Inference analysis resulted a more-resolved phylogeny that corroborated with traditional hypotheses of holometabolan relationships based on traditional hypotheses of holometabolan relationships and most of recently molecular study compared to 28S sequences. This finding provides the information on relationships of pests species, which infested several crops in Malaysia and also estimation on Holometabola's order relationships. The identification of the larval stages of insect pests could be done accurately, without waiting the emergence of adults and supported by the phylogenetic tree.

  19. Chemical analyses of geothermal waters and Strategic Petroleum Reserve brines for metals of economic importance

    SciTech Connect

    Harrar, J.E.; Raber, E.

    1984-01-01

    Waters from seven hydrothermal-geothermal, one geopressured-geothermal, and six Strategic Petroleum Reserve wells have been surveyed for 12 metals of economic importance using trace chemical analysis techniques. The elements sought were Cr, Co, Mn, Ta, Sn, V, Nb, Li, Sr, Pt, Au and Ag. Platinum was found at a concentration of approx. 50 ppb in a brine from the Salton Sea geothermal area. Brine from this region, as has been known from previous studies, is also rich in Li, Sr and Mn. Higher concentrations (approx. 900 ppm) of Sr are found in the high-salinity geopressured brines. None of the fluids contained interesting concentrations of the other metals. Good recovery of precious metals at sub-ppm concentrations from synthetic high salinity brines was achieved using Amborane reductive resin, but similar recovery in the laboratory using real brines could not be demonstrated. Several analytical techniques were compared in sensitivity for the determination of the precious metals; neutron activation analysis with carrier separation is the best for gold and platinum in geothermal brines. 26 references, 7 tables.

  20. Tracking cashew economically important diseases in the West African region using metagenomics

    PubMed Central

    Monteiro, Filipa; Romeiras, Maria M.; Figueiredo, Andreia; Sebastiana, Mónica; Baldé, Aladje; Catarino, Luís; Batista, Dora

    2015-01-01

    During the last decades, agricultural land-uses in West Africa were marked by dramatic shifts in the coverage of individual crops. Nowadays, cashew (Anacardium occidentale L.) is one of the most export-oriented horticulture crops, notably in Guinea-Bissau. Relying heavily on agriculture to increase their income, developing countries have been following a strong trend of moving on from traditional farming systems toward commercial production. Emerging infectious diseases, driven either by adaptation to local conditions or inadvertent importation of plant pathogens, are able to cause tremendous cashew production losses, with economic and social impact of which, in developing countries is often underestimated. Presently, plant genomics with metagenomics as an emergent tool, presents an enormous potential to better characterize diseases by providing extensive knowledge on plant pathogens at a large scale. In this perspective, we address metagenomics as a promising genomic tool to identify cashew fungal associated diseases as well as to discriminate the causal pathogens, aiming at obtaining tools to help design effective strategies for disease control and thus promote the sustainable production of cashew in West African Region. PMID:26175748

  1. Montane and coastal species diversification in the economically important Mexican grasshopper genus Sphenarium (Orthoptera: Pyrgomorphidae).

    PubMed

    Pedraza-Lara, Carlos; Barrientos-Lozano, Ludivina; Rocha-Sánchez, Aurora Y; Zaldívar-Riverón, Alejandro

    2015-03-01

    The genus Sphenarium (Pyrgomorphidae) is a small group of grasshoppers endemic to México and Guatemala that are economically and culturally important both as a food source and as agricultural pests. However, its taxonomy has been largely neglected mainly due to its conserved interspecific external morphology and the considerable intraspecific variation in colour pattern of some taxa. Here we examined morphological as well as mitochondrial and nuclear DNA sequence data to assess the species boundaries and evolutionary history in Sphenarium. Our morphological identification and DNA sequence-based species delimitation, carried out with three different approaches (DNA barcoding, general mixed Yule-coalescent model, Bayesian species delimitation), all recovered a higher number of putative species of Sphenarium than previously recognised. We unambiguously delimit seven species, and between five and ten additional species depending on the data/method analysed. Phylogenetic relationships within the genus strongly support two main clades, one exclusively montane, the other coastal. Divergence time estimates suggest late Miocene to Pliocene ages for the origin and most of the early diversification events in the genus, which were probably influenced by the formation of the Trans-Mexican Volcanic Belt. A series of Pleistocene events could have led to the current species diversification in both montane and coastal regions. This study not only reveals an overlooked species richness for the most popular edible insect in Mexico, but also highlights the influence of the dynamic geological and climatic history of the region in shaping its current diversity.

  2. Multispecies resource management of economically important marine plant communites of eastern Canada

    NASA Astrophysics Data System (ADS)

    Pringle, J. D.; Sharp, G. J.

    1980-03-01

    The annual 45,000 t harvest of six marine plant taxa, consisting principally of the alga Chondrus crispus, is worth 5 million annually to maritime fishermen. The harvesting techniques enable capture of associated biota and alter the abiotic structure of the habitat. Methods developed to assess ecological impact include permanent transects which are sampled for vegetation composition and dry biomass. C. crispus represents 80% of the plant biomass in commercial beds; 27 other genera comprise the remainder. Thirty-five associated invertebrate species include only one of direct economic importance, the lobster, Homarus americanus. On commercial Chondrus beds off western Prince Edward Island, lobsters were captured in basket dragrakes up to 5.4 h-1 during 1975 and 1976. Of the total lobster catch, the percentage injured by Chondrus dragrakes was 2.7% in 1975 and 1.3% in 1976. Chondrus dragrakes, as used in southwestern Nova Scotia, disrupt the drumlin substrate. Controlled dragraking for 2-h periods disrupted 0.25% to 1.5% of the bottom area. One month of normal harvest activity displaced 0.5% to 2.9% of the bottom of surveyed sites. A harvest of 1000 t of Laminaria spp. is projected for 1979. Dragrakes harvest entire plants averaging 5.0 ± 2.3 m in length. The residual population averaged 2.3 ± 1.9 m. Indirect effects of kelp harvesting on the benthic community are the subject of ongoing research.

  3. Sexual reproduction in Aspergillus species of medical or economical importance: why so fastidious?

    PubMed

    Kwon-Chung, Kyung J; Sugui, Janyce A

    2009-11-01

    Heterothallism is dependent upon the obligatory cross-mating between self-sterile homokaryotic individuals and represents a common pattern of sexuality in yeasts and molds. Heterothallic reproductive cycles have recently been discovered in three Aspergillus species of medical and economic importance, namely Aspergillus fumigatus,A. parasiticus and A. flavus. Together with Aspergillus udagawae (Neosartorya udagawae), heterothallism has now been discovered in a total of four aspergilli that affect human health or economy. These fungi appear to express relatively low levels of fertility compared to other heterothallic or homothallic aspergilli and require unusually fastidious environmental parameters to complete the sexual cycle. Because the purpose of sex is to reproduce, we favor the hypothesis that while fertility of these species is on the decline this is compensated by their proficiency to reproduce asexually in a wider range of environmental conditions. Heterothallism in these species could provide an invaluable tool for the recombinational analysis of factors relevant to pathogenicity or toxin production. There is concern, however, whether extensive recombinational analysis can be very practical in light of the fact that formation of ascospores in these species requires a long period of time and the construction of genetically marked strains is likely to decrease fertility even further.

  4. The genome-wide structure of two economically important indigenous Sicilian cattle breeds.

    PubMed

    Mastrangelo, S; Saura, M; Tolone, M; Salces-Ortiz, J; Di Gerlando, R; Bertolini, F; Fontanesi, L; Sardina, M T; Serrano, M; Portolano, B

    2014-11-01

    Genomic technologies, such as high-throughput genotyping based on SNP arrays, provided background information concerning genome structure in domestic animals. The aim of this work was to investigate the genetic structure, the genome-wide estimates of inbreeding, coancestry, effective population size (Ne), and the patterns of linkage disequilibrium (LD) in 2 economically important Sicilian local cattle breeds, Cinisara (CIN) and Modicana (MOD), using the Illumina Bovine SNP50K v2 BeadChip. To understand the genetic relationship and to place both Sicilian breeds in a global context, genotypes from 134 other domesticated bovid breeds were used. Principal component analysis showed that the Sicilian cattle breeds were closer to individuals of Bos taurus taurus from Eurasia and formed nonoverlapping clusters with other breeds. Between the Sicilian cattle breeds, MOD was the most differentiated, whereas the animals belonging to the CIN breed showed a lower value of assignment, the presence of substructure, and genetic links with the MOD breed. The average molecular inbreeding and coancestry coefficients were moderately high, and the current estimates of Ne were low in both breeds. These values indicated a low genetic variability. Considering levels of LD between adjacent markers, the average r(2) in the MOD breed was comparable to those reported for others cattle breeds, whereas CIN showed a lower value. Therefore, these results support the need of more dense SNP arrays for a high-power association mapping and genomic selection efficiency, particularly for the CIN cattle breed. Controlling molecular inbreeding and coancestry would restrict inbreeding depression, the probability of losing beneficial rare alleles, and therefore the risk of extinction. The results generated from this study have important implications for the development of conservation and/or selection breeding programs in these 2 local cattle breeds.

  5. Vocational Education and Training Plays an Important Role in Taiwan's Economic Miracle.

    ERIC Educational Resources Information Center

    Yuen, Steve Chi-Yin

    The explosive economic growth and rising prosperity of Taiwan is linked to the country's system of vocational education. Paralleling Taiwan's rapid economic transformation has been the growth of its national educational system. Both the government and the private sector have been making concerted efforts to develop education, resulting in constant…

  6. Epidemiological features and economical importance of bovine virus diarrhoea virus (BVDV) infections.

    PubMed

    Houe, H

    1999-01-01

    Infections with bovine virus diarrhoea virus (BVDV) are widespread throughout the world. Although the prevalence of infection varies among surveys, the infection tends to be endemic in many populations, reaching a maximum level of 1-2% of the cattle being persistently infected (PI) and 60-85% of the cattle being antibody positive. Persistently infected cattle are the main source for transmission of the virus. However, acutely infected cattle as well as other ruminants, either acutely or persistently infected, may transmit the virus. Transmission is most efficient by direct contact. However, as infections have been observed in closed, non-pasturing herds, other transmission routes seem likely to have some practical importance. Differences in BVDV prevalence among regions or introduction of virus in herds previously free of BVDV are often associated with particular epidemiological determinants such as cattle population density, animal trade and pasturing practices. However, on a few occasions there have been no obvious explanations for infection of individual herds. Estimates of economic losses due to BVDV infection vary depending on the immune status of the population and the pathogenicity of the infecting virus strains. Introduction of the infection into a totally susceptible population invariably causes extensive losses until a state of equilibrium is reached. Infection with highly virulent BVDV strains causing severe clinical signs and death after acute infection gives rise to substantial economical losses. At an estimated annual incidence of acute infections of 34%, the total annual losses were estimated as US$ 20 million per million calvings when modeling the losses due to a low-virulent BVDV strain. At the same incidence of infection, the losses due to a high-virulent BVDV strain were estimated as US$ 57 million per million calvings. Low-virulent BVDV infections caused maximum losses at an incidence of 45%, whereas high-virulent BVDV infections caused maximum

  7. The policy of import substitution as the basis for economic security and well-being of society

    NASA Astrophysics Data System (ADS)

    Makasheva, Yu S.; Makasheva, N. P.; Gromova, A. S.; Andreeva, N. V.; Ishtunov, S. A.

    2016-09-01

    The study presents the analysis of import substitution opportunities on separate branches of economic activity, preceding the realization of import substitution policy with the aim to support national economic security, which is essential for the contemporary society welfare insurance. Currently, social well-being is considered to be the reflection of economic activity, the instrument of state influence on the society, as well as an indicator of the social security system. Due to the fact that Russia is integrated into the world economy, the foreign-economic policy currently is playing an important role in the development of national security and the state's interest to the spheres of economy considering external and internal threats. Decline in external economic conditions may result in serious consequences for the functioning and development of the country as well as for the trade and investment activities, which will further lead to the decline in export, withdrawal of capital, recession of industrial production, trade and investment sphere, fall of GDP and living standards. Thus, considering the current state of instability in the world economy and the growing political tension in relation to Russian Federation, the measures to increase economic security in the country should be taken. The policy of import substitution is considered to be one of the major solutions nowadays.

  8. Relative importance of physical and economic factors in Appalachian coalbed gas assessment

    USGS Publications Warehouse

    Attanasi, E.D.

    1998-01-01

    In the 1995 National Assessment of Oil and Gas Resources prepared by the U.S. Geological Survey, only 20% of the assessed technically recoverable Appalachian Province coalbed gas resources were economic. Physical and economic variables are examined to explain the disparity between economic and technically recoverable coalbed gas. The Anticline and Syncline plays of the Northern Appalachian Basin, which account for 77% of the assessed technically recoverable coalbed gas, are not economic. Analysis shows marginal reductions in costs or rate of return will not turn these plays into commercial successes. Physical parameters that determine ultimate well recoverability and the rate of gas recovery are primary reasons the Northern Appalachian Basin plays are non-commercial. If the application of new well stimulation technology could offset slow gas desorption rates, Appalachian Province economic gas could increase to more then 70% of the technically recoverable gas. Similarly, if operators are able to develop strategies to selectively drill plays by avoiding dry holes and non-commercial occurrences, the economic fraction of technically recoverable gas could increase to over half.In the 1995 National Assessment of Oil and Gas Resources prepared by the U.S. Geological Survey, only 20% of the assessed technically recoverable Appalachian Province coalbed gas resources were economic. Physical and economic variables are examined to explain the disparity between economic and technically recoverable coalbed gas. The Anticline and Syncline plays of the Northern Appalachian Basin, which account for 77% of the assessed technically recoverable coalbed gas, are not economic. Analysis shows marginal reductions in costs or rate of return will not turn these plays into commercial successes. Physical parameters that determine ultimate well recoverability and the rate of gas recovery are primary reasons the Northern Appalachian Basin plays are non-commercial. If the application of new well

  9. Salt effects on functional traits in model and in economically important Lotus species.

    PubMed

    Uchiya, P; Escaray, F J; Bilenca, D; Pieckenstain, F; Ruiz, O A; Menéndez, A B

    2016-07-01

    A common stress on plants is NaCl-derived soil salinity. Genus Lotus comprises model and economically important species, which have been studied regarding physiological responses to salinity. Leaf area ratio (LAR), root length ratio (RLR) and their components, specific leaf area (SLA) and leaf mass fraction (LMF) and specific root length (SRL) and root mass fraction (RMF) might be affected by high soil salinity. We characterised L. tenuis, L. corniculatus, L. filicaulis, L. creticus, L. burtii and L. japonicus grown under different salt concentrations (0, 50, 100 and 150 mm NaCl) on the basis of SLA, LMF, SRL and RMF using PCA. We also assessed effects of different salt concentrations on LAR and RLR in each species, and explored whether changes in these traits provide fitness benefit. Salinity (150 mm NaCl) increased LAR in L. burtii and L. corniculatus, but not in the remaining species. The highest salt concentration caused a decrease of RLR in L. japonicus Gifu, but not in the remaining species. Changes in LAR and RLR would not be adaptive, according to adaptiveness analysis, with the exception of SLA changes in L. corniculatus. PCA revealed that under favourable conditions plants optimise surfaces for light and nutrient acquisition (SLA and SRL), whereas at higher salt concentrations they favour carbon allocation to leaves and roots (LMF and RMF) in detriment to their surfaces. PCA also showed that L. creticus subjected to saline treatment was distinguished from the remaining Lotus species. We suggest that augmented carbon partitioning to leaves and roots could constitute a salt-alleviating mechanism through toxic ion dilution.

  10. Genetic Linkage Mapping of Economically Important Traits in Cultivated Tetraploid Potato (Solanum tuberosum L.).

    PubMed

    Massa, Alicia N; Manrique-Carpintero, Norma C; Coombs, Joseph J; Zarka, Daniel G; Boone, Anne E; Kirk, William W; Hackett, Christine A; Bryan, Glenn J; Douches, David S

    2015-09-14

    The objective of this study was to construct a single nucleotide polymorphism (SNP)-based genetic map at the cultivated tetraploid level to locate quantitative trait loci (QTL) contributing to economically important traits in potato (Solanum tuberosum L.). The 156 F1 progeny and parents of a cross (MSL603) between "Jacqueline Lee" and "MSG227-2" were genotyped using the Infinium 8303 Potato Array. Furthermore, the progeny and parents were evaluated for foliar late blight reaction to isolates of the US-8 genotype of Phytophthora infestans (Mont.) de Bary and vine maturity. Linkage analyses and QTL mapping were performed using a novel approach that incorporates allele dosage information. The resulting genetic maps contained 1972 SNP markers with an average density of 1.36 marker per cM. QTL mapping identified the major source of late blight resistance in "Jacqueline Lee." The best SNP marker mapped ~0.54 Mb from a resistance hotspot on the long arm of chromosome 9. For vine maturity, the major-effect QTL was located on chromosome 5 with allelic effects from both parents. A candidate SNP marker for this trait mapped ~0.25 Mb from the StCDF1 gene, which is a candidate gene for the maturity trait. The identification of markers for P. infestans resistance will enable the introgression of multiple sources of resistance through marker-assisted selection. Moreover, the discovery of a QTL for late blight resistance not linked to the QTL for vine maturity provides the opportunity to use marker-assisted selection for resistance independent of the selection for vine maturity classifications. Copyright © 2015 Massa et al.

  11. Genetic Linkage Mapping of Economically Important Traits in Cultivated Tetraploid Potato (Solanum tuberosum L.)

    PubMed Central

    Massa, Alicia N.; Manrique-Carpintero, Norma C.; Coombs, Joseph J.; Zarka, Daniel G.; Boone, Anne E.; Kirk, William W.; Hackett, Christine A.; Bryan, Glenn J.; Douches, David S.

    2015-01-01

    The objective of this study was to construct a single nucleotide polymorphism (SNP)-based genetic map at the cultivated tetraploid level to locate quantitative trait loci (QTL) contributing to economically important traits in potato (Solanum tuberosum L.). The 156 F1 progeny and parents of a cross (MSL603) between “Jacqueline Lee” and “MSG227-2” were genotyped using the Infinium 8303 Potato Array. Furthermore, the progeny and parents were evaluated for foliar late blight reaction to isolates of the US-8 genotype of Phytophthora infestans (Mont.) de Bary and vine maturity. Linkage analyses and QTL mapping were performed using a novel approach that incorporates allele dosage information. The resulting genetic maps contained 1972 SNP markers with an average density of 1.36 marker per cM. QTL mapping identified the major source of late blight resistance in “Jacqueline Lee.” The best SNP marker mapped ∼0.54 Mb from a resistance hotspot on the long arm of chromosome 9. For vine maturity, the major-effect QTL was located on chromosome 5 with allelic effects from both parents. A candidate SNP marker for this trait mapped ∼0.25 Mb from the StCDF1 gene, which is a candidate gene for the maturity trait. The identification of markers for P. infestans resistance will enable the introgression of multiple sources of resistance through marker-assisted selection. Moreover, the discovery of a QTL for late blight resistance not linked to the QTL for vine maturity provides the opportunity to use marker-assisted selection for resistance independent of the selection for vine maturity classifications. PMID:26374597

  12. Assessment of oil content and fatty acid composition variability in two economically important Hibiscus species.

    PubMed

    Wang, Ming Li; Morris, Brad; Tonnis, Brandon; Davis, Jerry; Pederson, Gary A

    2012-07-04

    The Hibiscus genus encompasses more than 300 species, but kenaf (Hibiscus cannabinus L.) and roselle (Hibiscus sabdariffa L.) are the two most economically important species within the genus. Seeds from these two Hibiscus species contain a relatively high amount of oil with two unusual fatty acids: dihydrosterculic and vernolic acids. The fatty acid composition in the oil can directly affect oil quality and its utilization. However, the variability in oil content and fatty acid composition for these two species is unclear. For these two species, 329 available accessions were acquired from the USDA germplasm collection. Their oil content and fatty acid composition were determined by nuclear magnetic resonance (NMR) and gas chromatography (GC), respectively. Using NMR and GC analyses, we found that Hibiscus seeds on average contained 18% oil and seed oil was composed of six major fatty acids (each >1%) and seven minor fatty acids (each <1%). Hibiscus cannabinus seeds contained significantly higher amounts of oil (18.14%), palmitic (20.75%), oleic (28.91%), vernolic acids (VA, 4.16%), and significantly lower amounts of stearic (3.96%), linoleic (39.49%), and dihydrosterculic acids (DHSA, 1.08%) than H. sabdariffa seeds (17.35%, 18.52%, 25.16%, 3.52%, 4.31%, 44.72%, and 1.57%, respectively). For edible oils, a higher oleic/linoleic (O/L) ratio and lower level of DHSA are preferred, and for industrial oils a high level of VA is preferred. Our results indicate that seeds from H. cannabinus may be of higher quality than H. sabdariffa seeds for these reasons. Significant variability in oil content and major fatty acids was also detected within both species. The variability in oil content and fatty acid composition revealed from this study will be useful for exploring seed utilization and developing new cultivars in these Hibiscus species.

  13. Sustained H(2) production driven by photosynthetic water splitting in a unicellular cyanobacterium.

    PubMed

    Melnicki, Matthew R; Pinchuk, Grigoriy E; Hill, Eric A; Kucek, Leo A; Fredrickson, Jim K; Konopka, Allan; Beliaev, Alexander S

    2012-01-01

    The relationship between dinitrogenase-driven H(2) production and oxygenic photosynthesis was investigated in a unicellular cyanobacterium, Cyanothece sp. ATCC 51142, using a novel custom-built photobioreactor equipped with advanced process control. Continuously illuminated nitrogen-deprived cells evolved H(2) at rates up to 400 µmol ⋅ mg Chl(-1) ⋅ h(-1) in parallel with uninterrupted photosynthetic O(2) production. Notably, sustained coproduction of H(2) and O(2) occurred over 100 h in the presence of CO(2), with both gases displaying inverse oscillations which eventually dampened toward stable rates of 125 and 90 µmol ⋅ mg Chl(-1) ⋅ h(-1), respectively. Oscillations were not observed when CO(2) was omitted, and instead H(2) and O(2) evolution rates were positively correlated. The sustainability of the process was further supported by stable chlorophyll content, maintenance of baseline protein and carbohydrate levels, and an enhanced capacity for linear electron transport as measured by chlorophyll fluorescence throughout the experiment. In situ light saturation analyses of H(2) production displayed a strong dose dependence and lack of O(2) inhibition. Inactivation of photosystem II had substantial long-term effects but did not affect short-term H(2) production, indicating that the process is also supported by photosystem I activity and oxidation of endogenous glycogen. However, mass balance calculations suggest that carbohydrate consumption in the light may, at best, account for no more than 50% of the reductant required for the corresponding H(2) production over that period. Collectively, our results demonstrate that uninterrupted H(2) production in unicellular cyanobacteria can be fueled by water photolysis without the detrimental effects of O(2) and have important implications for sustainable production of biofuels. The study provides an important insight into the photophysiology of light-driven H(2) production by the nitrogen-fixing cyanobacterium

  14. Potential economic impact of introduction and spread of the red imported fire ant, Solenopsis invicta, in Hawaii

    USGS Publications Warehouse

    Gutrich, J.J.; VanGelder, E.; Loope, L.

    2007-01-01

    Globally, many invasive alien species have caused extensive ecological and economic damage from either accidental or intentional introduction. The red imported fire ant, Solenopsis invicta, has created billions of dollars in costs annually, spreading as an invasive species across the southern United States. In 1998, the red imported fire ant spread into California creating a highly probable future introduction via shipped products to Hawaii. This paper presents the estimation of potential economic impacts of the red imported fire ant (RIFA) to the state of Hawaii. Evaluation of impacts focuses on the economic sectors of (1) households, (2) agriculture (cattle and crop production), (3) infrastructure (cemeteries, churches, cities, electrical, telephone, and cable services, highways, hospitals and schools), (4) recreation, tourism and business (hotels/resort areas, golf courses, commercial businesses and tourists), and (5) government expenditures (with minimal intervention). The full annual economic costs of the red imported fire ant to Hawaii are estimated (in US$ 2006) to be $211 million/year, comprised of $77 million in damages and expenditures and $134 million in foregone outdoor opportunities to households and tourists. The present value of the projected costs of RIFA over a 20-year period after introduction total $2.5 billion. RIFA invasions across the globe indicate that economic cost-effective action in Hawaii entails implementation of prevention, early detection and rapid response treatment programs for RIFA. ?? 2007 Elsevier Ltd. All rights reserved.

  15. Health Economic Data in Reimbursement of New Medical Technologies: Importance of the Socio-Economic Burden as a Decision-Making Criterion.

    PubMed

    Iskrov, Georgi; Dermendzhiev, Svetlan; Miteva-Katrandzhieva, Tsonka; Stefanov, Rumen

    2016-01-01

    Assessment and appraisal of new medical technologies require a balance between the interests of different stakeholders. Final decision should take into account the societal value of new therapies. This perspective paper discusses the socio-economic burden of disease as a specific reimbursement decision-making criterion and calls for the inclusion of it as a counterbalance to the cost-effectiveness and budget impact criteria. Socio-economic burden is a decision-making criterion, accounting for diseases, for which the assessed medical technology is indicated. This indicator is usually researched through cost-of-illness studies that systematically quantify the socio-economic burden of diseases on the individual and on the society. This is a very important consideration as it illustrates direct budgetary consequences of diseases in the health system and indirect costs associated with patient or carer productivity losses. By measuring and comparing the socio-economic burden of different diseases to society, health authorities and payers could benefit in optimizing priority setting and resource allocation. New medical technologies, especially innovative therapies, present an excellent case study for the inclusion of socio-economic burden in reimbursement decision-making. Assessment and appraisal have been greatly concentrated so far on cost-effectiveness and budget impact, marginalizing all other considerations. In this context, data on disease burden and inclusion of explicit criterion of socio-economic burden in reimbursement decision-making may be highly beneficial. Realizing the magnitude of the lost socio-economic contribution resulting from diseases in question could be a reasonable way for policy makers to accept a higher valuation of innovative therapies.

  16. Health Economic Data in Reimbursement of New Medical Technologies: Importance of the Socio-Economic Burden as a Decision-Making Criterion

    PubMed Central

    Iskrov, Georgi; Dermendzhiev, Svetlan; Miteva-Katrandzhieva, Tsonka; Stefanov, Rumen

    2016-01-01

    Background: Assessment and appraisal of new medical technologies require a balance between the interests of different stakeholders. Final decision should take into account the societal value of new therapies. Objective: This perspective paper discusses the socio-economic burden of disease as a specific reimbursement decision-making criterion and calls for the inclusion of it as a counterbalance to the cost-effectiveness and budget impact criteria. Results/Conclusions: Socio-economic burden is a decision-making criterion, accounting for diseases, for which the assessed medical technology is indicated. This indicator is usually researched through cost-of-illness studies that systematically quantify the socio-economic burden of diseases on the individual and on the society. This is a very important consideration as it illustrates direct budgetary consequences of diseases in the health system and indirect costs associated with patient or carer productivity losses. By measuring and comparing the socio-economic burden of different diseases to society, health authorities and payers could benefit in optimizing priority setting and resource allocation. New medical technologies, especially innovative therapies, present an excellent case study for the inclusion of socio-economic burden in reimbursement decision-making. Assessment and appraisal have been greatly concentrated so far on cost-effectiveness and budget impact, marginalizing all other considerations. In this context, data on disease burden and inclusion of explicit criterion of socio-economic burden in reimbursement decision-making may be highly beneficial. Realizing the magnitude of the lost socio-economic contribution resulting from diseases in question could be a reasonable way for policy makers to accept a higher valuation of innovative therapies. PMID:27582707

  17. Interaction effects of mercury-pesticide combinations towards a cyanobacterium

    SciTech Connect

    Stratton, G.W.

    1985-05-01

    The present study supplies interaction data for combinations of mercuric ion (supplied as mercuric chloride), atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), and permethrin (3-phenoxybenzyl-(1RS)-cis,trans-3-(2,2-dichloro-vinyl)-2,2-dimethyl cyclopropanecarboxylate) when tested towards growth of the cyanobacterium (blue-green alga) Anabaena inaequalis. Mercury is one of the most important heavy metal pollutants and has been widely used in toxicology research. Atrazine is the most heavily used pesticide in the United States and its residues are widely distributed in terrestrial and aquatic ecosystems. Permethrin is an important insecticide with expanding markets and is presently being evaluated for its environmental impact. A. inaequalis has been used extensively in this laboratory in previous interaction studies.

  18. Socio-Economic Hazards and Impacts of Space Weather: The Important Range Between Mild and Extreme

    NASA Astrophysics Data System (ADS)

    Schrijver, Carolus J.

    2015-09-01

    Society needs to prepare for more severe space weather than it has experienced in the modern technological era. To enable that we must both quantify extreme-event characteristics and analyze impacts of lesser events that are frequent yet severe enough to be informative. Exploratory studies suggest that economic impacts of a century-level space hurricane and of a century of lesser space weather "gales" may turn out to be of the same order of magnitude. The economic benefits of effective mitigation of the impacts of space gales may substantially exceed the required investments, even as these investments provide valuable information to prepare for the worst possible storms.

  19. Mother's education is the most important factor in socio-economic inequality of child stunting in Iran.

    PubMed

    Emamian, Mohammad Hassan; Fateh, Mansooreh; Gorgani, Neman; Fotouhi, Akbar

    2014-09-01

    Malnutrition is one of the most important health problems, especially in developing countries. The present study aimed to describe the socio-economic inequality in stunting and its determinants in Iran for the first time. Cross-sectional, population-based survey, carried out in 2009. Using randomized cluster sampling, weight and height of children were measured and anthropometric indices were calculated based on child growth standards given by the WHO. Socio-economic status of families was determined using principal component analysis on household assets and social specifications of families. The concentration index was used to calculate socio-economic inequality in stunting and its determinants were measured by decomposition of this index. Factors affecting the gap between socio-economic groups were recognized by using the Oaxaca-Blinder decomposition method. Shahroud District in north-eastern Iran. Children (n 1395) aged <6 years. The concentration index for socio-economic inequality in stunting was -0·1913. Mother's education contributed 70 % in decomposition of this index. Mean height-for-age Z-score was -0·544 and -0·335 for low and high socio-economic groups, respectively. Mother's education was the factor contributing most to the gap between these two groups. There was a significant socio-economic inequality in the studied children. If mother's education is distributed equally in all the different groups of Iranian society, one can expect to eliminate 70 % of the socio-economic inequalities. Even in high socio-economic groups, the mean height-for-age Z-score was lower than the international standards. These issues emphasize the necessity of applying new interventions especially for the improvement of maternal education.

  20. Economics.

    PubMed

    Palley, Paul D; Parcero, Miriam E

    2016-10-01

    A review of literature in the calendar year 2015 dedicated to environmental policies and sustainable development, and economic policies. This review is divided into these sections: sustainable development, irrigation, ecosystems and water management, climate change and disaster risk management, economic growth, water supply policies, water consumption, water price regulation, and water price valuation.

  1. The Development of Interpersonal Aggression during Adolescence: The Importance of Parents, Siblings, and Family Economics

    ERIC Educational Resources Information Center

    Williams, Shannon Tierney; Conger, Katherine Jewsbury; Blozis, Shelley A.

    2007-01-01

    Latent growth curve modeling employed data from a longitudinal study of 451 sibling families to examine parents, siblings, and family economics as factors in individual differences in the developmental course of interpersonal aggression during adolescence. Findings suggest that individual change in interpersonal aggression during adolescence can…

  2. 50 CFR 14.33 - Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 1 2011-10-01 2011-10-01 false Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship. 14.33 Section 14.33 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING, POSSESSION, TRANSPORTATION,...

  3. 50 CFR 14.33 - Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 1 2014-10-01 2014-10-01 false Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship. 14.33 Section 14.33 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING, POSSESSION, TRANSPORTATION,...

  4. 50 CFR 14.33 - Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 1 2013-10-01 2013-10-01 false Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship. 14.33 Section 14.33 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING, POSSESSION, TRANSPORTATION,...

  5. 50 CFR 14.33 - Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 1 2012-10-01 2012-10-01 false Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship. 14.33 Section 14.33 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING, POSSESSION, TRANSPORTATION,...

  6. Personality Type and Student Performance in Upper-Level Economics Courses: The Importance of Race and Gender.

    ERIC Educational Resources Information Center

    Borg, Mary O.; Stranahan, Harriet A.

    2002-01-01

    Demonstrates that personality type is an important explanatory variable in student performance in upper level economics courses. Finds that certain personality types, combined with race and gender effects, produce students who outperform other students. Introverts and those with the Keirsey-Bates temperament combination of sensing/judging…

  7. The Importance of Socio-Economic Versus Environmental Risk Factors for Reported Dengue Cases in Java, Indonesia.

    PubMed

    Wijayanti, Siwi P M; Porphyre, Thibaud; Chase-Topping, Margo; Rainey, Stephanie M; McFarlane, Melanie; Schnettler, Esther; Biek, Roman; Kohl, Alain

    2016-09-01

    Dengue is a major mosquito-borne viral disease and an important public health problem. Identifying which factors are important determinants in the risk of dengue infection is critical in supporting and guiding preventive measures. In South-East Asia, half of all reported fatal infections are recorded in Indonesia, yet little is known about the epidemiology of dengue in this country. Hospital-reported dengue cases in Banyumas regency, Central Java were examined to build Bayesian spatial and spatio-temporal models assessing the influence of climatic, demographic and socio-economic factors on the risk of dengue infection. A socio-economic factor linking employment type and economic status was the most influential on the risk of dengue infection in the Regency. Other factors such as access to healthcare facilities and night-time temperature were also found to be associated with higher risk of reported dengue infection but had limited explanatory power. Our data suggest that dengue infections are triggered by indoor transmission events linked to socio-economic factors (employment type, economic status). Preventive measures in this area should therefore target also specific environments such as schools and work areas to attempt and reduce dengue burden in this community. Although our analysis did not account for factors such as variations in immunity which need further investigation, this study can advise preventive measures in areas with similar patterns of reported dengue cases and environment.

  8. The Importance of Socio-Economic Versus Environmental Risk Factors for Reported Dengue Cases in Java, Indonesia

    PubMed Central

    Chase-Topping, Margo; Rainey, Stephanie M.; McFarlane, Melanie; Schnettler, Esther; Biek, Roman; Kohl, Alain

    2016-01-01

    Background Dengue is a major mosquito-borne viral disease and an important public health problem. Identifying which factors are important determinants in the risk of dengue infection is critical in supporting and guiding preventive measures. In South-East Asia, half of all reported fatal infections are recorded in Indonesia, yet little is known about the epidemiology of dengue in this country. Methodology/Principal findings Hospital-reported dengue cases in Banyumas regency, Central Java were examined to build Bayesian spatial and spatio-temporal models assessing the influence of climatic, demographic and socio-economic factors on the risk of dengue infection. A socio-economic factor linking employment type and economic status was the most influential on the risk of dengue infection in the Regency. Other factors such as access to healthcare facilities and night-time temperature were also found to be associated with higher risk of reported dengue infection but had limited explanatory power. Conclusions/Significance Our data suggest that dengue infections are triggered by indoor transmission events linked to socio-economic factors (employment type, economic status). Preventive measures in this area should therefore target also specific environments such as schools and work areas to attempt and reduce dengue burden in this community. Although our analysis did not account for factors such as variations in immunity which need further investigation, this study can advise preventive measures in areas with similar patterns of reported dengue cases and environment. PMID:27603137

  9. The development of interpersonal aggression during adolescence: the importance of parents, siblings, and family economics.

    PubMed

    Williams, Shannon Tierney; Conger, Katherine Jewsbury; Blozis, Shelley A

    2007-01-01

    Latent growth curve modeling employed data from a longitudinal study of 451 sibling families to examine parents, siblings, and family economics as factors in individual differences in the developmental course of interpersonal aggression during adolescence. Findings suggest that individual change in interpersonal aggression during adolescence can be predicted by the gender and aggression of one's sibling; predictions varied by the gender composition of the sibling dyad. Rates of parental hostility predicted levels of interpersonal aggression for both older (mean age = 12 years) and younger siblings (mean age = 15), and growth in aggression for younger siblings. Family economic pressure predicted interpersonal aggression of both siblings indirectly through parental hostility. Implications for future research and preventive interventions are discussed.

  10. Economics.

    ERIC Educational Resources Information Center

    James, L. D.

    1978-01-01

    Presents a literature review of the economic aspects of water pollution control covering publications of 1976-77. This review also includes the policy issues of water management. A list of 77 references is presented. (HM)

  11. Economics.

    ERIC Educational Resources Information Center

    James, L. D.

    1978-01-01

    Presents a literature review of the economic aspects of water pollution control covering publications of 1976-77. This review also includes the policy issues of water management. A list of 77 references is presented. (HM)

  12. The Relationship Between Renewable Energy Production and Energy Imports Among Countries in the European Economic Area

    NASA Astrophysics Data System (ADS)

    Unbehaun, Sarah J.

    Most European countries must import fossil fuels due to a lack of domestic supplies but, in the interest of having a secure energy supply that is not susceptible to disruptions, would like to decrease their dependence on imports. It is possible that increasing renewable energy production could achieve this objective, in addition to providing environmental benefits. This analysis examines whether there is a relationship between renewable energy production and non-renewable energy imports, using data on European Union member countries and Norway from 1990-2014. Previous literature on the relationship between renewables and imports is scarce but provides suggestive evidence that production of renewables could lower import dependence, even if it cannot fully substitute for fossil fuels. However, the results of this analysis provide no evidence to support this position. Instead, I find that as renewable energy production increases, fossil fuel imports also increase.

  13. Migrant mortality from diabetes mellitus across Europe: the importance of socio-economic change.

    PubMed

    Vandenheede, Hadewijch; Deboosere, Patrick; Stirbu, Irina; Agyemang, Charles O; Harding, Seeromanie; Juel, Knud; Rafnsson, Snorri Björn; Regidor, Enrique; Rey, Grégoire; Rosato, Michael; Mackenbach, Johan P; Kunst, Anton E

    2012-02-01

    The first objective of this study was to determine and quantify variations in diabetes mortality by migrant status in different European countries. The second objective was to investigate the hypothesis that diabetes mortality is higher in migrant groups for whom the country of residence (COR) is more affluent than the country of birth (COB). We obtained mortality data from 7 European countries. To assess migrant diabetes mortality, we used direct standardization and Poisson regression. First, migrant mortality was estimated for each country separately. Then, we merged the data from all mortality registers. Subsequently, to examine the second hypothesis, we introduced gross domestic product (GDP) per capita of COB in the models, as an indicator of socio-economic circumstances. The overall pattern shows higher diabetes mortality in migrant populations compared to local-born populations. Mortality rate ratios (MRRs) were highest in migrants originating from either the Caribbean or South Asia. MRRs for the migrant population as a whole were 1.9 (95% CI 1.8-2.0) and 2.2 (95% CI 2.1-2.3) for men and women respectively. We furthermore found a consistently inverse association between GDP of COB and diabetes mortality. Most migrant groups have higher diabetes mortality rates than the local-born populations. Mortality rates are particularly high in migrants from North Africa, the Caribbean, South Asia or low-GDP countries. The inverse association between GDP of COB and diabetes mortality suggests that socio-economic change may be one of the key aetiological factors.

  14. Economics.

    ERIC Educational Resources Information Center

    Kemp, Rodger

    This course presents basic economic concepts and explores issues such as how goods and services are produced and distributed, what affects costs and profits, and how wealth is spread around or concentrated. The course is designed to be used with students enrolled in an adult high school diploma program; course content is appropriate to meet social…

  15. Genetic and genomic analyses for economically important traits and their applications in molecular breeding of cultured fish.

    PubMed

    Tong, JinGou; Sun, XiaoWen

    2015-02-01

    The traits of cultured fish must continually be genetically improved to supply high-quality animal protein for human consumption. Economically important fish traits are controlled by multiple gene quantitative trait loci (QTL), most of which have minor effects, but a few genes may have major effects useful for molecular breeding. In this review, we chose relevant studies on some of the most intensively cultured fish and concisely summarize progress on identifying and verifying QTLs for such traits as growth, disease and stress resistance and sex in recent decades. The potential applications of these major-effect genes and their associated markers in marker-assisted selection and molecular breeding, as well as future research directions are also discussed. These genetic and genomic analyses will be valuable for elucidating the mechanisms modulating economically important traits and to establish more effective molecular breeding techniques in fish.

  16. Genetic manipulation of a metabolic enzyme and a transcriptional regulator increasing succinate excretion from unicellular cyanobacterium.

    PubMed

    Osanai, Takashi; Shirai, Tomokazu; Iijima, Hiroko; Nakaya, Yuka; Okamoto, Mami; Kondo, Akihiko; Hirai, Masami Y

    2015-01-01

    Succinate is a building block compound that the U.S. Department of Energy (DOE) has declared as important in biorefineries, and it is widely used as a commodity chemical. Here, we identified the two genes increasing succinate production of the unicellular cyanobacterium Synechocystis sp. PCC 6803. Succinate was excreted under dark, anaerobic conditions, and its production level increased by knocking out ackA, which encodes an acetate kinase, and by overexpressing sigE, which encodes an RNA polymerase sigma factor. Glycogen catabolism and organic acid biosynthesis were enhanced in the mutant lacking ackA and overexpressing sigE, leading to an increase in succinate production reaching five times of the wild-type levels. Our genetic and metabolomic analyses thus demonstrated the effect of genetic manipulation of a metabolic enzyme and a transcriptional regulator on succinate excretion from this cyanobacterium with the data based on metabolomic technique.

  17. Genetic manipulation of a metabolic enzyme and a transcriptional regulator increasing succinate excretion from unicellular cyanobacterium

    PubMed Central

    Osanai, Takashi; Shirai, Tomokazu; Iijima, Hiroko; Nakaya, Yuka; Okamoto, Mami; Kondo, Akihiko; Hirai, Masami Y.

    2015-01-01

    Succinate is a building block compound that the U.S. Department of Energy (DOE) has declared as important in biorefineries, and it is widely used as a commodity chemical. Here, we identified the two genes increasing succinate production of the unicellular cyanobacterium Synechocystis sp. PCC 6803. Succinate was excreted under dark, anaerobic conditions, and its production level increased by knocking out ackA, which encodes an acetate kinase, and by overexpressing sigE, which encodes an RNA polymerase sigma factor. Glycogen catabolism and organic acid biosynthesis were enhanced in the mutant lacking ackA and overexpressing sigE, leading to an increase in succinate production reaching five times of the wild-type levels. Our genetic and metabolomic analyses thus demonstrated the effect of genetic manipulation of a metabolic enzyme and a transcriptional regulator on succinate excretion from this cyanobacterium with the data based on metabolomic technique. PMID:26500619

  18. Report: the current situation of sanitary landfills in Brazil and the importance of the application of economic models.

    PubMed

    Neto, Raul Oliveira; Petter, Carlos Otávio; Cortina, José Luis

    2009-12-01

    We present the development stage of the sanitary landfills in Brazil in the context of urban solid residue management, demonstrating the necessity and importance of the employment of economic models. In the article, a cost estimate model is proposed as the basis for studies to be applied by sector management, including the city council, companies, consultants and engineers, contributing to the choice of new areas, public bids, municipal consortia and private public partnerships.

  19. Economic analysis and costing of animal health: a literature review of methods and importance.

    PubMed

    Dehove, A; Commault, J; Petitclerc, M; Teissier, M; Macé, J

    2012-08-01

    Myriads of data, a host of methods, but no single universal indicator. The Performance of Veterinary Services (PVS) Gap Analysis helps to quantify the needs of national Veterinary Services. In a world of scarce public financial resources and heightened transparency and accountability, official Veterinary Services (national Veterinary Authorities) must be able to justify their needs in economic and budgetary terms to their line minister, national parliament and the public at large, or in negotiations with donors. Animal health and Veterinary Service activities are a global public good. It is the responsibility of governments to maintain animal health systems, including networks for the surveillance and control of animal diseases to ensure the early detection of suspected animal disease outbreaks, a rapid response and, where possible, eradication of animal disease outbreaks 'at source'. The establishment of animal health systems is a core responsibility of the State, and it requires the use of public funds, although it does not preclude public-private partnerships and strategies for ensuring complementarity between the partners concerned. The PVS Gap Analysis mission of the World Organisation for Animal Health (OIE) is a method for analysing and quantifying disparities between a baseline situation (determined by PVS Evaluation using the OIE PVS Tool) and the target levels set by the country itself in accordance with its priorities. An added advantage is that the method can be used for training and awareness raising.

  20. Quantity and economic importance of nine selected by-products used in California dairy rations.

    PubMed

    Grasser, L A; Fadel, J G; Garnett, I; DePeters, E J

    1995-04-01

    Food processing representatives, brokers, nutritionists, livestock producers, and trade associations were surveyed to quantify 9 by-products used for feeding livestock during 1992 in California. The commodities were almond hulls, dried beet pulp, wet brewers grains, wet citrus pulp, pressed citrus pulp, wet corn gluten feed, corn gluten meal, whole cottonseed, and rice bran. The 9 by-products contributed over 2.5 million tonnes and about 27% of the total feed concentrate moved within California during 1992. Market value of these 9 by-products was almost .25 billion dollars. Whole cottonseed accounted for about 31% of the total tonnage of these 9 by-products and provided about 66% of the total CP and 53% of the total NEL of these 9 by-products. The by-products were more valuable as energy sources than CP sources compared with NEL from corn and CP from soybean meal, respectively. Calculations of milk production, based on the CP content or NEL content of the by-products, showed that these 9 by-products could have contributed sufficient CP or NEL for over 31% of the milk produced in California during 1992. Ration formulations demonstrated that the economic value of by-products changed with feedstuffs available and, in general, would be used in rations over a range of market prices.

  1. Synergistic allelochemicals from a freshwater cyanobacterium

    PubMed Central

    Leão, Pedro N.; Pereira, Alban R.; Liu, Wei-Ting; Ng, Julio; Pevzner, Pavel A.; Dorrestein, Pieter C.; König, Gabriele M.; Vasconcelos, Vitor M.; Gerwick, William H.

    2010-01-01

    The ability of cyanobacteria to produce complex secondary metabolites with potent biological activities has gathered considerable attention due to their potential therapeutic and agrochemical applications. However, the precise physiological or ecological roles played by a majority of these metabolites have remained elusive. Several studies have shown that cyanobacteria are able to interfere with other organisms in their communities through the release of compounds into the surrounding medium, a phenomenon usually referred to as allelopathy. Exudates from the freshwater cyanobacterium Oscillatoria sp. had previously been shown to inhibit the green microalga Chlorella vulgaris. In this study, we observed that maximal allelopathic activity is highest in early growth stages of the cyanobacterium, and this provided sufficient material for isolation and chemical characterization of active compounds that inhibited the growth of C. vulgaris. Using a bioassay-guided approach, we isolated and structurally characterized these metabolites as cyclic peptides containing several unusually modified amino acids that are found both in the cells and in the spent media of Oscillatoria sp. cultures. Strikingly, only the mixture of the two most abundant metabolites in the cells was active toward C. vulgaris. Synergism was also observed in a lung cancer cell cytotoxicity assay. The binary mixture inhibited other phytoplanktonic organisms, supporting a natural function of this synergistic mixture of metabolites as allelochemicals. PMID:20534563

  2. Canada's Most Important Economic Investment: Increasing Access to College Education and Training. ACAATO Document

    ERIC Educational Resources Information Center

    Association of Colleges of Applied Arts and Technology of Ontario, 2004

    2004-01-01

    For Canada to succeed, all Canadians must have the opportunity to develop and use their skills and knowledge to the fullest. So said the government of Prime Minister Paul Martin in the Speech from the Throne that opened the 37th Parliament of Canada in February 2004: "Investing in people will be Canada's most important economic…

  3. The economics of prescription drug prices, government intervention, and the importation of drugs from Canada.

    PubMed

    Openshaw, Matthew S

    2005-01-01

    Popular attention has focused on the skyrocketing health care costs in the United States and specifically on increasing insurance and prescription drug prices. Individuals and some local governments have advocated importing price-controlled prescription drugs from Canada to help ease the financial burden. What effects would this have on consumer prices, drug companies' incentives, and the development of new medications?

  4. Prevalence and economic importance of cystic echinococcosis in slaughtered ruminants in Burdur, Turkey.

    PubMed

    Umur, S

    2003-06-01

    This study was conducted between April 2000 and March 2001, in 12-month period. During the study, local slaughterhouses were visited periodically for 1 year to examine the internal organs (livers, lungs, spleens and hearts) for the presence of cysts and total 1355 cattle, 218 sheep and 104 goats were examined for the cystic echinococcosis (CE). It was found that 13.5% of cattle, 26.6% of sheep and 22.1% of goats were infected with this disease. While cysts in cattle (P < 0.001) and goats (P > 0.05) were found mostly in lungs (88.5 and 82.6%, respectively), but they were mostly found in livers (P > 0.05) in sheep. In addition to this, three spleens and one heart in cattle were infected with CE. In this study, the prevalence of CE and the number of cysts in ruminants were found different when the cattle, sheep and goats examined were stratified based on age. The prevalence and the number of cysts increased with age approaching an asymptotic prevalence of one in the oldest animals (P < 0.05). The number of cysts in cattle, sheep and goats were increasing at a rate of 0.31, 0.63 and 0.42/year, respectively. The economic decrease in the value of the carcasses because of the discarded liver and lung as a result of CE was estimated as 1.1% (7.5 US dollars per cattle) for cattle, 4.37% (3.2 US dollars per sheep) for sheep and 4.26% (2.9 US dollars per goat) for goats. The minimum total loss for all infected animals was determined to be 583 US dollars in infected animals, based on the market prices in the year 2002.

  5. The importance of surgeon experience for clinical and economic outcomes from thyroidectomy.

    PubMed Central

    Sosa, J A; Bowman, H M; Tielsch, J M; Powe, N R; Gordon, T A; Udelsman, R

    1998-01-01

    OBJECTIVE: To determine whether individual surgeon experience is associated with improved short-term clinical and economic outcomes for patients with benign and malignant thyroid disease who underwent thyroid procedures in Maryland between 1991 and 1996. SUMMARY BACKGROUND DATA: There is a prevailing belief that surgeon experience affects patient outcomes in endocrine surgery, but there is a paucity of objective evidence outside of clinical series published by experienced surgeons that supports this view. METHODS: A cross-sectional analysis of all patients who underwent thyroidectomy in Maryland between 1991 and 1996 was conducted using a computerized statewide hospital discharge data base. Surgeons were categorized by volume of thyroidectomies over the 6-year study period: A (1 to 9 cases), B (10 to 29 cases), C (30 to 100 cases), and D (>100 cases). Multivariate regression was used to assess the relation between surgeon caseload and in-hospital complications, length of stay, and total hospital charges, adjusting for case mix and hospital volume. RESULTS: The highest-volume surgeons (group D) performed the greatest proportion of total thyroidectomies among the 5860 discharges, and they were more likely to operate on patients with cancer. After adjusting for case mix and hospital volume, highest-volume surgeons had the shortest length of stay (1.4 days vs. 1.7 days for groups B and C and 1.9 days for group A) and the lowest complication rate (5.1 % vs. 6.1% for groups B and C and 8.6% for group A). Length of stay and complications were more determined by surgeon experience than hospital volume, which had no consistent association with outcomes. CONCLUSIONS: Individual surgeon experience is significantly associated with complication rates and length of stay for thyroidectomy. PMID:9742915

  6. U.S. Irrigation. Extent and Economic Importance. Agriculture Information Bulletin Number 523.

    ERIC Educational Resources Information Center

    Day, John C.; Horner, Gerald L.

    Data for the years 1974, 1978, 1982, and 1984 are used to identify the principal features of irrigated farming in the United States and to assess the importance of irrigation to the farm economy. Irrigation of U.S. acreage declined 5.6 million acres between 1978 and 1984 to 44.7 million acres. In 1982 irrigated acreage represented 6 percent of the…

  7. DNA barcodes for bio-surveillance: regulated and economically important arthropod plant pests.

    PubMed

    Ashfaq, Muhammad; Hebert, Paul D N

    2016-11-01

    Many of the arthropod species that are important pests of agriculture and forestry are impossible to discriminate morphologically throughout all of their life stages. Some cannot be differentiated at any life stage. Over the past decade, DNA barcoding has gained increasing adoption as a tool to both identify known species and to reveal cryptic taxa. Although there has not been a focused effort to develop a barcode library for them, reference sequences are now available for 77% of the 409 species of arthropods documented on major pest databases. Aside from developing the reference library needed to guide specimen identifications, past barcode studies have revealed that a significant fraction of arthropod pests are a complex of allied taxa. Because of their importance as pests and disease vectors impacting global agriculture and forestry, DNA barcode results on these arthropods have significant implications for quarantine detection, regulation, and management. The current review discusses these implications in light of the presence of cryptic species in plant pests exposed by DNA barcoding.

  8. Wheat forecast economics effect study. [value of improved information on crop inventories, production, imports and exports

    NASA Technical Reports Server (NTRS)

    Mehra, R. K.; Rouhani, R.; Jones, S.; Schick, I.

    1980-01-01

    A model to assess the value of improved information regarding the inventories, productions, exports, and imports of crop on a worldwide basis is discussed. A previously proposed model is interpreted in a stochastic control setting and the underlying assumptions of the model are revealed. In solving the stochastic optimization problem, the Markov programming approach is much more powerful and exact as compared to the dynamic programming-simulation approach of the original model. The convergence of a dual variable Markov programming algorithm is shown to be fast and efficient. A computer program for the general model of multicountry-multiperiod is developed. As an example, the case of one country-two periods is treated and the results are presented in detail. A comparison with the original model results reveals certain interesting aspects of the algorithms and the dependence of the value of information on the incremental cost function.

  9. Development of microsatellites in Labisia pumila (Myrsinaceae), an economically important Malaysian herb.

    PubMed

    Tnah, Lee Hong; Lee, Chai Ting; Lee, Soon Leong; Ng, Chin Hong; Ng, Kevin Kit Siong

    2014-06-01

    The exploitation of Labisia pumila for commercial demand is gradually increasing. It is therefore important that conservation is prioritized to ensure sustainable utilization. We developed microsatellites for L. pumila var. alata and evaluated their polymorphism across var. alata, var. pumila, and var. lanceolata. • Ten polymorphic microsatellites of L. pumila were developed using the magnetic bead hybridization selection approach. A total of 84, 48, and 66 alleles were observed in L. pumila var. alata, var. pumila, and var. lanceolata, respectively. The species is likely a tetraploid, with the majority of the loci exhibiting up to four alleles per individual. • This is the first report on the development of microsatellites in L. pumila. The microsatellites will provide a good basis for investigating the population genetics of the species and will serve as a useful tool for DNA profiling.

  10. Development of microsatellites in Labisia pumila (Myrsinaceae), an economically important Malaysian herb1

    PubMed Central

    Tnah, Lee Hong; Lee, Chai Ting; Lee, Soon Leong; Ng, Chin Hong; Ng, Kevin Kit Siong

    2014-01-01

    • Premise of the study: The exploitation of Labisia pumila for commercial demand is gradually increasing. It is therefore important that conservation is prioritized to ensure sustainable utilization. We developed microsatellites for L. pumila var. alata and evaluated their polymorphism across var. alata, var. pumila, and var. lanceolata. • Methods and Results: Ten polymorphic microsatellites of L. pumila were developed using the magnetic bead hybridization selection approach. A total of 84, 48, and 66 alleles were observed in L. pumila var. alata, var. pumila, and var. lanceolata, respectively. The species is likely a tetraploid, with the majority of the loci exhibiting up to four alleles per individual. • Conclusions: This is the first report on the development of microsatellites in L. pumila. The microsatellites will provide a good basis for investigating the population genetics of the species and will serve as a useful tool for DNA profiling. PMID:25202631

  11. Cryptic diversity and habitat partitioning in an economically important aphid species complex.

    PubMed

    Savory, F R; Ramakrishnan, U

    2015-03-01

    Cardamom Bushy Dwarf Virus (CBDV) is an aphid-borne nanovirus which infects large cardamom, Amomum subulatum (Zingiberaceae family), in the Himalayan foothills of Northeast India, Nepal and Bhutan. Two aphid species have been reported to transmit CBDV, including Pentalonia nigronervosa and Micromyzus kalimpongensis (also described as Pentalonia kalimpongensis). However, P. nigronervosa was recently split into two species which exhibit different host plant affiliations. Whilst P. nigronervosa primarily feeds on banana plants, Pentaloniacaladii (previously considered a 'form' of P. nigronervosa) typically feeds on plants belonging to the Araceae, Heliconiaceae and Zingiberaceae families. This raises the possibility that CBDV vectors that were originally described as P. nigronervosa correspond to P. caladii. Accurate identification of vector species is important for understanding disease dynamics and for implementing management strategies. However, closely related species can be difficult to distinguish based on morphological characteristics. In this study, we used molecular markers (two mitochondrial loci and one nuclear locus) and Bayesian phylogenetic analyses to identify aphid specimens collected from 148 CBDV infected plants at a range of locations and elevations throughout Sikkim and the Darjeeling district of West Bengal (Northeast India). Our results revealed the presence of a diversity of lineages, comprising up to six distinct species in at least two related genera. These included the three species mentioned above, an unidentified Pentalonia species and two lineages belonging to an unknown genus. Surprisingly, P. caladii was only detected on a single infected plant, indicating that this species may not play an important role in CBDV transmission dynamics. Distinct elevation distributions were observed for the different species, demonstrating that the community composition of aphids which feed on large cardamom plants changes across an elevation gradient

  12. Factors contributing to the public health and economic importance of waterborne zoonotic parasites.

    PubMed

    Gajadhar, Alvin A; Allen, John R

    2004-12-09

    This is the first of a series of review articles in a Special Issue publication on waterborne zoonotic parasites. A brief historical overview of the occurrence and importance of waterborne parasites, dating from early civilization is presented. The article considers the diversity of parasites including protozoa, nematodes, cestodes and trematodes and the related zoonotic organism microsporidia. Many of the life cycle stages and their characteristics, which make parasites environmentally resistant and suitable for waterborne transmission are discussed. Surfaces of transmission stages consist of multiple layers of proteins, lipids, chitin or other substances capable of withstanding a variety of physical and chemical treatments. Delivery of waterborne parasites is facilitated by various mass distribution systems to consumers, and by transport and intermediate hosts such as fish and filter-feeding invertebrates which are consumed by humans. The article discusses the trends in global warming and climate change and potential for concurrent rise in waterborne disease outbreaks due to parasites. Impacts of technological modernization and globalization on the transmission of zoonotic waterborne zoonotic parasites are considered, including the effects of large-scale agricultural practices, rapid transportation of goods, and widespread movement of individuals and animals. Finally, transmission features and parasite attributes which contribute to concerns about accidental or orchestrated waterborne disease outbreaks are discussed.

  13. Parasites of economically important bivalves from the southern coast of Bahia State, Brazil.

    PubMed

    Zeidan, Gabriela Calvi; Luz, Mariane Dos Santos Aguiar; Boehs, Guisla

    2012-01-01

    This study investigated the parasites of three commercially important bivalve species (Crassostrea rhizophorae, Mytella guyanensis and Lucina pectinata) from the southern coast of Bahia, Brazil. A total of 540 specimens were collected in August 2009 and February 2010, at three localities. The bivalve specimens were measured on their longest axis, opened, and macroscopically examined for the presence of parasites or signs of disease. They were then fixed in Davidson' solution and subjected to routine histological processing, with paraffin embedding and H&E staining; next, the specimens were examined under a light microscope. No parasites were observed associated with L. pectinata. Rickettsia-like organisms (RLOs), Sphenophrya sp. (Ciliophora), Nematopsis sp. (Apicomplexa), Urastoma sp. (Turbellaria) and Bucephalus sp. (Digenea) were observed in both C. rhizophorae and M. guyanensis, as well as Ancistrocoma sp. (Ciliophora) and Tylocephalum sp. (Cestoda) in the former. A high prevalence of Nematopsis sp. was seen, but caused no apparent damage to the host. Bucephalus sp. caused the destruction of tissues, with castration, but showed low prevalence. The other parasites occurred in low prevalence and intensity, without causing significant damage.

  14. Local knowledge of traditional fishermen on economically important crabs (Decapoda: Brachyura) in the city of Conde, Bahia State, Northeastern Brazil.

    PubMed

    de Magalhães, Henrique Fernandes; Costa Neto, Eraldo Medeiros; Schiavetti, Alexandre

    2012-07-02

    This article records the traditional knowledge of crab gatherers in the city of Conde, in the North Coast Region of Bahia State, Northeastern Brazil. Data on biological and ecological aspects of economically important brachyuran crustaceans have been obtained from semi-structured interviews and in loco observations conducted from September 2007 to December 2009. A total of 57 fishermen of both genders, aged between 10 and 78 years have been interviewed (individually or collectively) in different contexts; interviewees were asked about aspects such as external morphology, life cycle, trophic ecology, and spatial and temporal distribution of the major economically important brachyuran crustaceans in the region. Seven fishing communities were visited: Siribinha, Sítio do Conde, Poças, Ilha das Ostras, Cobó, Buri and Sempre Viva. Data were analyzed by comparing the information provided by participants with those from the specialized academic literature. The results show that artisanal fishermen have a wide ranging and well-grounded knowledge on the ecological and biological aspects of crustaceans. Crab gatherers of Conde know about growth and reproductive behavior of the animals they interact with, especially with regard to the three major biological aspects: "molt", "walking dance" and "spawning". This knowledge constitutes an important source of information that should be considered in studies of management and sustainable use of fishery resources in the North Coast Region of Bahia State.

  15. TRIPATH: A Biological Genetic and Genomic Database of Three Economically Important Fungal Pathogen of Wheat – Rust: Smut: Bunt

    PubMed Central

    Garg, Swati; Pandey, Dinesh; Taj, Gohar; Goel, Anshita; Kumar, Anil

    2014-01-01

    Wheat, the major source of vegetable protein in human diet, provides staple food globally for a large proportion of the human population. With higher protein content than other major cereals, wheat has great socio- economic importance. Nonetheless for wheat, three important fungal pathogens i.e. rust, smut and bunt are major cause of significant yield losses throughout the world. Researchers are putting up a strong fight against devastating wheat pathogens, and have made progress in tracking and controlling disease outbreaks from East Africa to South Asia. The aim of the present work hence was to develop a fungal pathogens database dedicated to wheat, gathering information about different pathogen species and linking them to their biological classification, distribution and control. Towards this end, we developed an open access database Tripath: A biological, genetic and genomic database of economically important wheat fungal pathogens – rust: smut: bunt. Data collected from peer-reviewed publications and fungal pathogens were added to the customizable database through an extended relational design. The strength of this resource is in providing rapid retrieval of information from large volumes of text at a high degree of accuracy. Database TRIPATH is freely accessible. Availability http://www.gbpuat-cbsh.ac.in/departments/bi/database/tripath/ PMID:25187689

  16. Local knowledge of traditional fishermen on economically important crabs (Decapoda: Brachyura) in the city of Conde, Bahia State, Northeastern Brazil

    PubMed Central

    2012-01-01

    Background This article records the traditional knowledge of crab gatherers in the city of Conde, in the North Coast Region of Bahia State, Northeastern Brazil. Methods Data on biological and ecological aspects of economically important brachyuran crustaceans have been obtained from semi-structured interviews and in loco observations conducted from September 2007 to December 2009. A total of 57 fishermen of both genders, aged between 10 and 78 years have been interviewed (individually or collectively) in different contexts; interviewees were asked about aspects such as external morphology, life cycle, trophic ecology, and spatial and temporal distribution of the major economically important brachyuran crustaceans in the region. Seven fishing communities were visited: Siribinha, Sítio do Conde, Poças, Ilha das Ostras, Cobó, Buri and Sempre Viva. Data were analyzed by comparing the information provided by participants with those from the specialized academic literature. Results The results show that artisanal fishermen have a wide ranging and well-grounded knowledge on the ecological and biological aspects of crustaceans. Crab gatherers of Conde know about growth and reproductive behavior of the animals they interact with, especially with regard to the three major biological aspects: “molt”, “walking dance” and “spawning”. Conclusion This knowledge constitutes an important source of information that should be considered in studies of management and sustainable use of fishery resources in the North Coast Region of Bahia State. PMID:22449069

  17. The importance of actions and the worth of an object: dissociable neural systems representing core value and economic value.

    PubMed

    Brosch, Tobias; Coppin, Géraldine; Schwartz, Sophie; Sander, David

    2012-06-01

    Neuroeconomic research has delineated neural regions involved in the computation of value, referring to a currency for concrete choices and decisions ('economic value'). Research in psychology and sociology, on the other hand, uses the term 'value' to describe motivational constructs that guide choices and behaviors across situations ('core value'). As a first step towards an integration of these literatures, we compared the neural regions computing economic value and core value. Replicating previous work, economic value computations activated a network centered on medial orbitofrontal cortex. Core value computations activated medial prefrontal cortex, a region involved in the processing of self-relevant information and dorsal striatum, involved in action selection. Core value ratings correlated with activity in precuneus and anterior prefrontal cortex, potentially reflecting the degree to which a core value is perceived as internalized part of one's self-concept. Distributed activation pattern in insula and ACC allowed differentiating individual core value types. These patterns may represent evaluation profiles reflecting prototypical fundamental concerns expressed in the core value types. Our findings suggest mechanisms by which core values, as motivationally important long-term goals anchored in the self-schema, may have the behavioral power to drive decisions and behaviors in the absence of immediately rewarding behavioral options.

  18. The importance of actions and the worth of an object: dissociable neural systems representing core value and economic value

    PubMed Central

    Coppin, Géraldine; Schwartz, Sophie; Sander, David

    2012-01-01

    Neuroeconomic research has delineated neural regions involved in the computation of value, referring to a currency for concrete choices and decisions (‘economic value’). Research in psychology and sociology, on the other hand, uses the term ‘value’ to describe motivational constructs that guide choices and behaviors across situations (‘core value’). As a first step towards an integration of these literatures, we compared the neural regions computing economic value and core value. Replicating previous work, economic value computations activated a network centered on medial orbitofrontal cortex. Core value computations activated medial prefrontal cortex, a region involved in the processing of self-relevant information and dorsal striatum, involved in action selection. Core value ratings correlated with activity in precuneus and anterior prefrontal cortex, potentially reflecting the degree to which a core value is perceived as internalized part of one’s self-concept. Distributed activation pattern in insula and ACC allowed differentiating individual core value types. These patterns may represent evaluation profiles reflecting prototypical fundamental concerns expressed in the core value types. Our findings suggest mechanisms by which core values, as motivationally important long-term goals anchored in the self-schema, may have the behavioral power to drive decisions and behaviors in the absence of immediately rewarding behavioral options. PMID:21642352

  19. Green Algae from Coal Bed Methane Ponds as a Source of Fertilizer for Economically Important Plants of Montana

    NASA Astrophysics Data System (ADS)

    Ogunsakin, O. R.; Apple, M. E.; Zhou, X.; Peyton, B.

    2016-12-01

    The Tongue River Basin of northeastern Wyoming and southeastern Montana is the location of natural gas reserves and coal bed methane (CBM) acreage. Although the water that emanates from CBM extraction varies with site, it is generally of higher quality than the waters produced by conventional oil and gas wells, in part because it is low in volatile organic compounds. However, since CBM water contains dissolved solids, including sodium (Na), bicarbonate (HCO3) and chloride (Cl) ions, the water must be treated before it can be discharged into the river or wetlands, or used for stock ponds or irrigation. Several ponds have been constructed to serve as a holding facility for CBM water. Algae from the CBM ponds of the Tongue River Basin have the potential to be utilized as fertilizer on economically important plants of Montana. Two very important crop plants of Montana are wheat, Triticum aestivum, and potatoes, Solanum tuberosum. To explore this potential, isolates of unicellular green algae (Chlorella sp.) from the CBM ponds were cultured in aerated vessels with Bold's Basic Growth Medium and natural and/or supplemental light. Algal biomass was condensed in and collected from a valved funnel, after which cell density was determined via light microscopy and a hemacytometer. Algal/water slurries with known nutrient contents were added to seedlings of hard winter wheat, T.aestivum, grown in a greenhouse for three months before harves. When compared to wheat provided with just water, or with water and a commercially available fertilizer, the wheat fertilized with algae had a higher chlorophyll content, more tillers (side shoots), and a higher ratio of influorescences (groups of flowers) per stem. In a related experiment, Ranger Russet seed potatoes, S. tuberosum were given just water, water and Hoagland's nutrient solution, or water with algae in order to compare aboveground growth and potato production among the treatments. The results of this study suggest that

  20. ParaCalc®--a novel tool to evaluate the economic importance of worm infections on the dairy farm.

    PubMed

    Charlier, Johannes; Van der Voort, Mariska; Hogeveen, Henk; Vercruysse, Jozef

    2012-03-23

    Subclinical infections with gastrointestinal nematodes and liver fluke are important causes of production losses in grazing cattle. Although there is an extensive compilation of literature describing the effect of these infections on animal performance, only a few attempts have been made to convert these production losses to an economic cost. Here, we propose a novel tool (ParaCalc(®)), available as a web-application, to provide herd-specific estimates of the costs of these infections on dairy farms. ParaCalc(®) is a deterministic spread-sheet model where results from diagnostic methods to monitor the helminth infection status on a herd and anthelmintic usage are used as input parameters. Default values are provided to describe the effects of the infections on production and the cost of these production losses, but the latter can be adapted to improve the herd-specificity of the cost estimate. After development, ParaCalc(®) was applied on input parameters that were available for 93 Belgian dairy herds. In addition, the tool was provided to 6 veterinarians and their user experiences were evaluated. The estimated median [25th-75th percentile] cost per year per cow was € 46 [29-58] and € 6 [0-19] for gastrointestinal nematode and liver fluke infection, respectively. For both infections, the major components in the total costs were those associated with milk production losses in the adult cows. The veterinarians evaluated ParaCalc(®) as a useful tool to raise the farmers' awareness on the costs of worm infections, providing added value for their services. However, the score given for user-friendliness was diverse among users. Although the model behind ParaCalc(®) is a strong simplification of the real herd processes inducing economic losses, the tool may be used in the future to support economic decisions on helminth control.

  1. Appling Remote Sensing Technique to Monitoring Spatial Expansion of Important Cities in China-Indochina Peninsula Economic Corridor

    NASA Astrophysics Data System (ADS)

    Li, J.; Wang, H.; Wang, G.; Zhai, H.; Han, M.; Liu, X.

    2017-09-01

    Since twentieth Century, the process of economic globalization has made great progress, and Southeast Asia has developed rapidly under the background of international industrial transferring. In this paper, the 6 important nodes cities in China - Indochina Peninsula along the economic corridor are took as study area. The main data is time series Landsat data. The method of object-oriented random forest classification was used to extract the classification results of study area from 2000 to 2015. The urban expansion of the node cities was evaluated by calculating the expansion speed of the impervious surface and the landscape pattern metrics. The results indicated that the method of object oriented random forest classification can effectively extract the urban impervious surface. the overall accuracy is over 81 %, and the Kappa coefficient is over 0.82. In the past 15 years, the expansion speed of Vientiane city was fastest in 6 countries. The area of urban impervious surface expanded 8 times than that of 2000.The pattern of expansion is summarized as "gather first-diffuse then", "diffuse first-gather then" and "gather". Overall, the process of urbanization of these cities are still in the rising period.

  2. Geosciences: an important tool for the ethical advancement and the economic and cultural development of our society

    NASA Astrophysics Data System (ADS)

    Vito Graziano, Gian

    2013-04-01

    The development of a society in economic, cultural and ethical terms is always linked to the growth of the scientific and technical knowledge. It follows that the downsizing of the scientific research brings to a slower growth or even, as it is happening these days in Italy, a real cultural decay. The consequences of the economic crisis are evident to everyone, but it is precisely in times of crisis that the best strategies to restart the economy and give new cultural perspectives to society are studied. The crisis is also contrasted with ideas and ability to put them into practice. This, however, also presupposes a different cultural approach, which has to also include a review of values and beliefs, and a redefinition of the objectives to be pursued. This approach is modeled on the basis of several positive experiences that a country can boast. Among these experiences, there are those arising from the scientific culture: geology, for example, such as chemistry, biology or other sciences, can help to change vision. The research and practice of Earth sciences have important implications on the life and activities of the population and therefore the geoscientists, as active subjects in the society, should question their role and responsibilities. They should be at the service of society, especially in the fields of prevention from natural hazards and valorization of georesources. In this sense they can give important indications for economy and development of their country. The Italian Council of Geologists (Consiglio Nazionale dei Geologi - CNG) acts with the aim of highlighting the social role of geoscientists, hoping for a new cultural Renaissance, which leads to new researches, without obscurantism or prejudices. In an authoritative way, the CNG intends to put this social role before any demand from the professional category. Therefore, it has recently presented its political Manifesto, geared essentially to the good governance of the territory, to all the

  3. Genomic sequencing and microsatellite marker development for Boswellia papyrifera, an economically important but threatened tree native to dry tropical forests

    PubMed Central

    Addisalem, A. B.; Esselink, G. Danny; Bongers, F.; Smulders, M. J. M.

    2015-01-01

    Microsatellite (or simple sequence repeat, SSR) markers are highly informative DNA markers often used in conservation genetic research. Next-generation sequencing enables efficient development of large numbers of SSR markers at lower costs. Boswellia papyrifera is an economically important tree species used for frankincense production, an aromatic resinous gum exudate from bark. It grows in dry tropical forests in Africa and is threatened by a lack of rejuvenation. To help guide conservation efforts for this endangered species, we conducted an analysis of its genomic DNA sequences using Illumina paired-end sequencing. The genome size was estimated at 705 Mb per haploid genome. The reads contained one microsatellite repeat per 5.7 kb. Based on a subset of these repeats, we developed 46 polymorphic SSR markers that amplified 2–12 alleles in 10 genotypes. This set included 30 trinucleotide repeat markers, four tetranucleotide repeat markers, six pentanucleotide markers and six hexanucleotide repeat markers. Several markers were cross-transferable to Boswellia pirrotae and B. popoviana. In addition, retrotransposons were identified, the reads were assembled and several contigs were identified with similarity to genes of the terpene and terpenoid backbone synthesis pathways, which form the major constituents of the bark resin. PMID:25573702

  4. Amplified Fragment Length Polymorphism Mapping of Quantitative Trait Loci for Economically Important Traits in the Silkworm, Bombyx mori

    PubMed Central

    Mirhoseini, Seyed Z; Rabiei, Babak; Potki, Payam; Dalirsefat, Seyed B

    2010-01-01

    Cocoon related characteristics are economically important traits in the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae). In this study a genetic linkage map was developed that identified QTL controlling the cocoon weight, cocoon shell weight, and cocoon shell percentage using 161 amplified fragment length polymorphism (AFLP) markers. Twenty PstI/TaqI primer combinations were employed to genotype 78 F2 progenies derived from a cross between P107 Japanese inbred line and Khorasan Lemon Iranian native strain. Among polymorphic markers, 159 AFLP markers were assigned to 24 linkage groups at the LOD threshold of 2.5 that varied in length from 4 to 299 cM. The total length of the linkage map was 2747 cM, giving an average marker resolution of 19.31 cM. A total of 21 AFLP markers were identified that were distributed over the ten linkage groups linked to the three studied traits using the composite interval mapping method. The explained variation rate by QTL controlling cocoon weight, cocoon shell weight, and cocoon shell percentage ranged from 0.02% to 64.85%, 0.2% to 49.11%, and 0.04% to 84.20%, respectively. These QTL controlled by different actions as well as under dominance, additive, partial dominance, dominance, and over dominance. PMID:21070171

  5. Efficient germ-line transformation of the economically important pest species Lucilia cuprina and Lucilia sericata (Diptera, Calliphoridae).

    PubMed

    Concha, Carolina; Belikoff, Esther J; Carey, Brandi-lee; Li, Fang; Schiemann, Anja H; Scott, Maxwell J

    2011-01-01

    The green blowfly species Lucilia cuprina and Lucilia sericata are economically important pests for the sheep industries of Australia and New Zealand. L. cuprina has long been considered a good target for a genetic pest management program. In addition, L. sericata maggots are used in the cleaning of wounds and necrotic tissue of patients suffering from ulcers that are difficult to treat by other methods. Development of efficient transgenesis methods would greatly facilitate the development of strains ideal for genetic control programs or could potentially improve "maggot therapy". We have previously reported the germ-line transformation of L. cuprina and the design of a "female killing system" that could potentially be applied to this species. However, the efficiency of transformation obtained was low and transformed lines were difficult to detect due to the low expression of the EGFP marker used. Here we describe an efficient and reliable method for germ-line transformation of L. cuprina using new piggyBac vector and helper plasmids containing the strong promoter from the L. cuprina hsp83 gene to drive expression of the transposase and fluorescent protein marker gene. We also report, for the first time, the germ-line transformation of L. sericata using the new piggyBac vector/helper combination. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Genome Editing with Engineered Nucleases in Economically Important Animals and Plants: State of the Art in the Research Pipeline.

    PubMed

    Sovová, Tereza; Kerins, Gerard; Demnerová, Kateřina; Ovesná, Jaroslava

    2017-01-01

    After induced mutagenesis and transgenesis, genome editing is the next step in the development of breeding techniques. Genome editing using site-directed nucleases - including meganucleases, zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and the CRISPR/Cas9 system - is based on the mechanism of double strand breaks. The nuclease is directed to cleave the DNA at a specific place of the genome which is then repaired by natural repair mechanisms. Changes are introduced during the repair that are either accidental or can be targeted if a DNA template with the desirable sequence is provided. These techniques allow making virtually any change to the genome including specific DNA sequence changes, gene insertion, replacements or deletions with unprecedented precision and specificity while being less laborious and more straightforward compared to traditional breeding techniques or transgenesis. Therefore, the research in this field is developing quickly and, apart from model species, multiple studies have focused on economically important species and agronomically important traits that were the key subjects of this review. In plants, studies have been undertaken on disease resistance, herbicide tolerance, nutrient metabolism and nutritional value. In animals, the studies have mainly focused on disease resistance, meat production and allergenicity of milk. However, none of the promising studies has led to commercialization despite several patent applications. The uncertain legal status of genome-editing methods is one of the reasons for poor commercial development, as it is not clear whether the products would fall under the GMO regulation. We believe this issue should be clarified soon in order to allow promising methods to reach their full potential.

  7. High-yield production of extracellular type-I cellulose by the cyanobacterium Synechococcus sp. PCC 7002

    PubMed Central

    Zhao, Chi; Li, Zhongkui; Li, Tao; Zhang, Yingjiao; Bryant, Donald A; Zhao, Jindong

    2015-01-01

    Cellulose synthase, encoded by the cesA gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium Synechococcus sp. PCC 7002 naturally contains cellulose. Cellulose occurs as a possibly laminated layer between the inner and outer membrane, as well as being an important component of the extracellular glycocalyx in this cyanobacterium. Overexpression of six genes, cmc–ccp–cesAB–cesC–cesD–bgl, from Gluconacetobacter xylinus in Synechococcus sp. PCC 7002 resulted in very high-yield production of extracellular type-I cellulose. High-level cellulose production only occurred when the native cesA gene was inactivated and when cells were grown at low salinity. This system provides a method for the production of lignin-free cellulose from sunlight and CO2 for biofuel production and other biotechnological applications. PMID:27462405

  8. High-yield production of extracellular type-I cellulose by the cyanobacterium Synechococcus sp. PCC 7002.

    PubMed

    Zhao, Chi; Li, Zhongkui; Li, Tao; Zhang, Yingjiao; Bryant, Donald A; Zhao, Jindong

    2015-01-01

    Cellulose synthase, encoded by the cesA gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium Synechococcus sp. PCC 7002 naturally contains cellulose. Cellulose occurs as a possibly laminated layer between the inner and outer membrane, as well as being an important component of the extracellular glycocalyx in this cyanobacterium. Overexpression of six genes, cmc-ccp-cesAB-cesC-cesD-bgl, from Gluconacetobacter xylinus in Synechococcus sp. PCC 7002 resulted in very high-yield production of extracellular type-I cellulose. High-level cellulose production only occurred when the native cesA gene was inactivated and when cells were grown at low salinity. This system provides a method for the production of lignin-free cellulose from sunlight and CO2 for biofuel production and other biotechnological applications.

  9. Insecticide Resistance and Malaria Vector Control: The Importance of Fitness Cost Mechanisms in Determining Economically Optimal Control Trajectories

    PubMed Central

    Brown, Zachary S.; Dickinson, Katherine L.; Kramer, Randall A.

    2014-01-01

    The evolutionary dynamics of insecticide resistance in harmful arthropods has economic implications, not only for the control of agricultural pests (as has been well studied), but also for the control of disease vectors, such as malaria-transmitting Anopheles mosquitoes. Previous economic work on insecticide resistance illustrates the policy relevance of knowing whether insecticide resistance mutations involve fitness costs. Using a theoretical model, this article investigates economically optimal strategies for controlling malaria-transmitting mosquitoes when there is the potential for mosquitoes to evolve resistance to insecticides. Consistent with previous literature, we find that fitness costs are a key element in the computation of economically optimal resistance management strategies. Additionally, our models indicate that different biological mechanisms underlying these fitness costs (e.g., increased adult mortality and/or decreased fecundity) can significantly alter economically optimal resistance management strategies. PMID:23448053

  10. Identification of aphid (Hemiptera: Aphididae) species of economic importance in Kenya using DNA barcodes and PCR-RFLP-based approach.

    PubMed

    Kinyanjui, G; Khamis, F M; Mohamed, S; Ombura, L O; Warigia, M; Ekesi, S

    2016-02-01

    Aphids are among pests of economic importance throughout the world. Together with transmitting plant viruses, aphids are capable of inflicting severe crop production losses. They also excrete honeydew that favours the growth of sooty mold which reduces the quality of vegetables and fruits and hence their market values. Rapid and accurate identification of aphids to the species level is a critical component in effective pest management and plant quarantine systems. Even though morphological taxonomy has made a tremendous impact on species-level identifications, polymorphism, morphological plasticity and immature stages are among the many challenges to accurate identification. In addition, their small size, presence of cryptic species and damaged specimens dictate the need for a strategy that will ensure timely and accurate identification. In this study, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based on mitochondrial cytochrome c oxidase subunit I gene and DNA barcoding were applied to identify different aphid species collected from different agro-ecological zones of Kenya. Three restriction enzymes RsaI, AluI and Hinf1 produced patterns that allowed unambiguous identification of the species except Aphis craccivora and Aphis fabae. Analyses of the barcode region indicated intraspecific and interspecific sequence divergences of 0.08 and 6.63%, respectively. DNA barcoding identified all species, including the morphologically indistinguishable A. craccivora and A. fabae and separated two subspecies of A. fabae. Based on these results, both PCR-RFLPs and DNA barcoding could provide quick and accurate tools for identification of aphid species within Aphididae subsequently aiding in effective pest management programmes and enhance plant quarantine systems.

  11. Complete Sequence and Analysis of Plastid Genomes of Two Economically Important Red Algae: Pyropia haitanensis and Pyropia yezoensis

    PubMed Central

    Wang, Li; Mao, Yunxiang; Kong, Fanna; Li, Guiyang; Ma, Fei; Zhang, Baolong; Sun, Peipei; Bi, Guiqi; Zhang, Fangfang; Xue, Hongfan; Cao, Min

    2013-01-01

    Background Pyropia haitanensis and P. yezoensis are two economically important marine crops that are also considered to be research models to study the physiological ecology of intertidal seaweed communities, evolutionary biology of plastids, and the origins of sexual reproduction. This plastid genome information will facilitate study of breeding, population genetics and phylogenetics. Principal Findings We have fully sequenced using next-generation sequencing the circular plastid genomes of P. hatanensis (195,597 bp) and P. yezoensis (191,975 bp), the largest of all the plastid genomes of the red lineage sequenced to date. Organization and gene contents of the two plastids were similar, with 211–213 protein-coding genes (including 29–31 unknown-function ORFs), 37 tRNA genes, and 6 ribosomal RNA genes, suggesting a largest coding capacity in the red lineage. In each genome, 14 protein genes overlapped and no interrupted genes were found, indicating a high degree of genomic condensation. Pyropia maintain an ancient gene content and conserved gene clusters in their plastid genomes, containing nearly complete repertoires of the plastid genes known in photosynthetic eukaryotes. Similarity analysis based on the whole plastid genome sequences showed the distance between P. haitanensis and P. yezoensis (0.146) was much smaller than that of Porphyra purpurea and P. haitanensis (0.250), and P. yezoensis (0.251); this supports re-grouping the two species in a resurrected genus Pyropia while maintaining P. purpurea in genus Porphyra. Phylogenetic analysis supports a sister relationship between Bangiophyceae and Florideophyceae, though precise phylogenetic relationships between multicellular red alage and chromists were not fully resolved. Conclusions These results indicate that Pyropia have compact plastid genomes. Large coding capacity and long intergenic regions contribute to the size of the largest plastid genomes reported for the red lineage. Possessing the largest

  12. Complete sequence and analysis of plastid genomes of two economically important red algae: Pyropia haitanensis and Pyropia yezoensis.

    PubMed

    Wang, Li; Mao, Yunxiang; Kong, Fanna; Li, Guiyang; Ma, Fei; Zhang, Baolong; Sun, Peipei; Bi, Guiqi; Zhang, Fangfang; Xue, Hongfan; Cao, Min

    2013-01-01

    Pyropia haitanensis and P. yezoensis are two economically important marine crops that are also considered to be research models to study the physiological ecology of intertidal seaweed communities, evolutionary biology of plastids, and the origins of sexual reproduction. This plastid genome information will facilitate study of breeding, population genetics and phylogenetics. We have fully sequenced using next-generation sequencing the circular plastid genomes of P. hatanensis (195,597 bp) and P. yezoensis (191,975 bp), the largest of all the plastid genomes of the red lineage sequenced to date. Organization and gene contents of the two plastids were similar, with 211-213 protein-coding genes (including 29-31 unknown-function ORFs), 37 tRNA genes, and 6 ribosomal RNA genes, suggesting a largest coding capacity in the red lineage. In each genome, 14 protein genes overlapped and no interrupted genes were found, indicating a high degree of genomic condensation. Pyropia maintain an ancient gene content and conserved gene clusters in their plastid genomes, containing nearly complete repertoires of the plastid genes known in photosynthetic eukaryotes. Similarity analysis based on the whole plastid genome sequences showed the distance between P. haitanensis and P. yezoensis (0.146) was much smaller than that of Porphyra purpurea and P. haitanensis (0.250), and P. yezoensis (0.251); this supports re-grouping the two species in a resurrected genus Pyropia while maintaining P. purpurea in genus Porphyra. Phylogenetic analysis supports a sister relationship between Bangiophyceae and Florideophyceae, though precise phylogenetic relationships between multicellular red alage and chromists were not fully resolved. These results indicate that Pyropia have compact plastid genomes. Large coding capacity and long intergenic regions contribute to the size of the largest plastid genomes reported for the red lineage. Possessing the largest coding capacity and ancient gene content yet

  13. Antagonistic interactions between filamentous heterotrophs and the cyanobacterium Nostoc muscorum.

    PubMed

    Svercel, Miroslav; Saladin, Bianca; van Moorsel, Sofia J; Wolf, Sarah; Bagheri, Homayoun C

    2011-09-13

    Little is known about interactions between filamentous heterotrophs and filamentous cyanobacteria. Here, interactions between the filamentous heterotrophic bacteria Fibrella aestuarina (strain BUZ 2) and Fibrisoma limi (BUZ 3) with an axenic strain of the autotrophic filamentous cyanobacterium Nostoc muscorum (SAG 25.82) were studied in mixed cultures under nutrient rich (carbon source present in medium) and poor (carbon source absent in medium) conditions. F. aestuarina BUZ 2 significantly reduced the cyanobacterial population whereas F. limi BUZ 3 did not. Physical contact between heterotrophs and autotroph was observed and the cyanobacterial cells showed some level of damage and lysis. Therefore, either contact lysis or entrapment with production of extracellular compounds in close vicinity of host cells could be considered as potential modes of action.The supernatants from pure heterotrophic cultures did not have an effect on Nostoc cultures. However, supernatant from mixed cultures of BUZ 2 and Nostoc had a negative effect on cyanobacterial growth, indicating that the lytic compounds were only produced in the presence of Nostoc.The growth and survival of tested heterotrophs was enhanced by the presence of Nostoc or its metabolites, suggesting that the heterotrophs could utilize the autotrophs and its products as a nutrient source. However, the autotroph could withstand and out-compete the heterotrophs under nutrient poor conditions. Our results suggest that the nutrients in cultivation media, which boost or reduce the number of heterotrophs, were the important factor influencing the outcome of the interplay between filamentous heterotrophs and autotrophs. For better understanding of these interactions, additional research is needed. In particular, it is necessary to elucidate the mode of action for lysis by heterotrophs, and the possible defense mechanisms of the autotrophs.

  14. Reducing GHG emissions through genetic improvement for feed efficiency: effects on economically important traits and enteric methane production.

    PubMed

    Basarab, J A; Beauchemin, K A; Baron, V S; Ominski, K H; Guan, L L; Miller, S P; Crowley, J J

    2013-06-01

    Genetic selection for residual feed intake (RFI) is an indirect approach for reducing enteric methane (CH4) emissions in beef and dairy cattle. RFI is moderately heritable (0.26 to 0.43), moderately repeatable across diets (0.33 to 0.67) and independent of body size and production, and when adjusted for off-test ultrasound backfat thickness (RFI fat) is also independent of body fatness in growing animals. It is highly dependent on accurate measurement of individual animal feed intake. Within-animal repeatability of feed intake is moderate (0.29 to 0.49) with distinctive diurnal patterns associated with cattle type, diet and genotype, necessitating the recording of feed intake for at least 35 days. In addition, direct measurement of enteric CH4 production will likely be more variable and expensive than measuring feed intake and if conducted should be expressed as CH4 production (g/animal per day) adjusted for body size, growth, body composition and dry matter intake (DMI) or as residual CH4 production. A further disadvantage of a direct CH4 phenotype is that the relationships of enteric CH4 production on other economically important traits are largely unknown. Selection for low RFI fat (efficient, -RFI fat) will result in cattle that consume less dry matter (DMI) and have an improved feed conversion ratio (FCR) compared with high RFI fat cattle (inefficient; +RFI fat). Few antagonistic effects have been reported for the relationships of RFI fat on carcass and meat quality, fertility, cow lifetime productivity and adaptability to stress or extensive grazing conditions. Low RFI fat cattle also produce 15% to 25% less enteric CH4 than +RFI fat cattle, since DMI is positively related to enteric methane (CH4) production. In addition, lower DMI and feeding duration and frequency, and a different rumen bacterial profile that improves rumen fermentation in -RFI fat cattle may favor a 1% to 2% improvement in dry matter and CP digestibility compared with +RFI fat cattle. Rate

  15. Metabolic streamlining in an open-ocean nitrogen-fixing cyanobacterium.

    PubMed

    Tripp, H James; Bench, Shellie R; Turk, Kendra A; Foster, Rachel A; Desany, Brian A; Niazi, Faheem; Affourtit, Jason P; Zehr, Jonathan P

    2010-03-04

    Nitrogen (N(2))-fixing marine cyanobacteria are an important source of fixed inorganic nitrogen that supports oceanic primary productivity and carbon dioxide removal from the atmosphere. A globally distributed, periodically abundant N(2)-fixing marine cyanobacterium, UCYN-A, was recently found to lack the oxygen-producing photosystem II complex of the photosynthetic apparatus, indicating a novel metabolism, but remains uncultivated. Here we show, from metabolic reconstructions inferred from the assembly of the complete UCYN-A genome using massively parallel pyrosequencing of paired-end reads, that UCYN-A has a photofermentative metabolism and is dependent on other organisms for essential compounds. We found that UCYN-A lacks a number of major metabolic pathways including the tricarboxylic acid cycle, but retains sufficient electron transport capacity to generate energy and reducing power from light. Unexpectedly, UCYN-A has a reduced genome (1.44 megabases) that is structurally similar to many chloroplasts and some bacteria, in that it contains inverted repeats of ribosomal RNA operons. The lack of biosynthetic pathways for several amino acids and purines suggests that this organism depends on other organisms, either in close association or in symbiosis, for critical nutrients. However, size fractionation experiments using natural populations have so far not provided evidence of a symbiotic association with another microorganism. The UCYN-A cyanobacterium is a paradox in evolution and adaptation to the marine environment, and is an example of the tight metabolic coupling between microorganisms in oligotrophic oceanic microbial communities.

  16. Diurnal Rhythms Result in Significant Changes in the Cellular Protein Complement in the Cyanobacterium Cyanothece 51142

    SciTech Connect

    Stockel, Jana; Jacobs, Jon M.; Elvitigala, Thanura R.; Liberton, Michelle L.; Welsh, Eric A.; Polpitiya, Ashoka D.; Gritsenko, Marina A.; Nicora, Carrie D.; Koppenaal, David W.; Smith, Richard D.; Pakrasi, Himadri B.

    2011-02-22

    Cyanothece sp. ATCC 51142 is a diazotrophic cyanobacterium notable for its ability to perform oxygenic photosynthesis and dinitrogen fixation in the same single cell. Previous transcriptional analysis revealed that the existence of these incompatible cellular processes largely depends on tightly synchronized expression programs involving ,30% of genes in the genome. To expand upon current knowledge, we have utilized sensitive proteomic approaches to examine the impact of diurnal rhythms on the protein complement in Cyanothece 51142. We found that 250 proteins accounting for,5% of the predicted ORFs from the Cyanothece 51142 genome and 20% of proteins detected under alternating light/dark conditions exhibited periodic oscillations in their abundances. Our results suggest that altered enzyme activities at different phases during the diurnal cycle can be attributed to changes in the abundance of related proteins and key compounds. The integration of global proteomics and transcriptomic data further revealed that post-transcriptional events are important for temporal regulation of processes such as photosynthesis in Cyanothece 51142. This analysis is the first comprehensive report on global quantitative proteomics in a unicellular diazotrophic cyanobacterium and uncovers novel findings about diurnal rhythms.

  17. Cellular and functional specificity among ferritin-like proteins in the multicellular cyanobacterium Nostoc punctiforme.

    PubMed

    Ekman, Martin; Sandh, Gustaf; Nenninger, Anja; Oliveira, Paulo; Stensjö, Karin

    2014-03-01

    Ferritin-like proteins constitute a remarkably heterogeneous protein family, including ferritins, bacterioferritins and Dps proteins. The genome of the filamentous heterocyst-forming cyanobacterium Nostoc punctiforme encodes five ferritin-like proteins. In the present paper, we report a multidimensional characterization of these proteins. Our phylogenetic and bioinformatics analyses suggest both structural and physiological differences among the ferritin-like proteins. The expression of these five genes responded differently to hydrogen peroxide treatment, with a significantly higher rise in transcript level for Npun_F3730 as compared with the other four genes. A specific role for Npun_F3730 in the cells tolerance against hydrogen peroxide was also supported by the inactivation of Npun_F3730, Npun_R5701 and Npun_R6212; among these, only the ΔNpun_F3730 strain showed an increased sensitivity to hydrogen peroxide compared with wild type. Analysis of promoter-GFP reporter fusions of the ferritin-like genes indicated that Npun_F3730 and Npun_R5701 were expressed in all cell types of a diazotrophic culture, while Npun_F6212 was expressed specifically in heterocysts. Our study provides the first comprehensive analysis combining functional differentiation and cellular specificity within this important group of proteins in a multicellular cyanobacterium. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

  18. Indirect Interspecies Regulation: Transcriptional and Physiological Responses of a Cyanobacterium to Heterotrophic Partnership

    PubMed Central

    McClure, Ryan S.; Thiel, Vera; Sadler, Natalie C.; Kim, Young-Mo; Chrisler, William B.; Hill, Eric A.; Romine, Margaret F.; Jansson, Janet K.; Fredrickson, Jim K.; Beliaev, Alexander S.

    2017-01-01

    ABSTRACT The mechanisms by which microbes interact in communities remain poorly understood. Here, we interrogated specific interactions between photoautotrophic and heterotrophic members of a model consortium to infer mechanisms that mediate metabolic coupling and acclimation to partnership. This binary consortium was composed of a cyanobacterium, Thermosynechococcus elongatus BP-1, which supported growth of an obligate aerobic heterotroph, Meiothermus ruber strain A, by providing organic carbon, O2, and reduced nitrogen. Species-resolved transcriptomic analyses were used in combination with growth and photosynthesis kinetics to infer interactions and the environmental context under which they occur. We found that the efficiency of biomass production and resistance to stress induced by high levels of dissolved O2 increased, beyond axenic performance, as a result of heterotrophic partnership. Coordinated transcriptional responses transcending both species were observed and used to infer specific interactions resulting from the synthesis and exchange of resources. The cyanobacterium responded to heterotrophic partnership by altering expression of core genes involved with photosynthesis, carbon uptake/fixation, vitamin synthesis, and scavenging of reactive oxygen species (ROS). IMPORTANCE This study elucidates how a cyanobacterial primary producer acclimates to heterotrophic partnership by modulating the expression levels of key metabolic genes. Heterotrophic bacteria can indirectly regulate the physiology of the photoautotrophic primary producers, resulting in physiological changes identified here, such as increased intracellular ROS. Some of the interactions inferred from this model system represent putative principles of metabolic coupling in phototrophic-heterotrophic partnerships. PMID:28289730

  19. 75 FR 64351 - The Economic Effects of Significant U.S. Import Restraints: Seventh Update; Special Topic: Global...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-19

    ... Supply Chains AGENCY: United States International Trade Commission. ACTION: Notice of seventh update..., include an overview of global supply chains, including the economic forces behind them and current U.S... reveal the operations of the firm supplying the information. By order of the Commission. Issued: October...

  20. 75 FR 28652 - Certain Environmental Goods: Probable Economic Effect of Duty-Free Treatment for U.S. Imports...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... extent practical, identify tariff and non-tariff measures, government programs, and technological... section 332(g) of the Tariff Act of 1930 (19 U.S.C. 1332(g)), the U.S. International Trade Commission... probable economic effect on U.S. industries and on U.S. consumers of reducing U.S. tariffs to zero...

  1. Transcriptome analyses reveal protein and domain families that delineate stage-related development in the economically important parasitic nematodes, Ostertagia ostertagi and Cooperia oncophora

    USDA-ARS?s Scientific Manuscript database

    Cooperia oncophora and Ostertagia ostertagi are among the most important gastrointestinal nematodes of cattle worldwide. The economic losses caused by these parasites are on the order of hundreds of millions of dollars per year. Conventional treatment of these parasites is through anthelmintic drug...

  2. An Early-Branching Microbialite Cyanobacterium Forms Intracellular Carbonates

    NASA Astrophysics Data System (ADS)

    Couradeau, Estelle; Benzerara, Karim; Gérard, Emmanuelle; Moreira, David; Bernard, Sylvain; Brown, Gordon E.; López-García, Purificación

    2012-04-01

    Cyanobacteria have affected major geochemical cycles (carbon, nitrogen, and oxygen) on Earth for billions of years. In particular, they have played a major role in the formation of calcium carbonates (i.e., calcification), which has been considered to be an extracellular process. We identified a cyanobacterium in modern microbialites in Lake Alchichica (Mexico) that forms intracellular amorphous calcium-magnesium-strontium-barium carbonate inclusions about 270 nanometers in average diameter, revealing an unexplored pathway for calcification. Phylogenetic analyses place this cyanobacterium within the deeply divergent order Gloeobacterales. The chemical composition and structure of the intracellular precipitates suggest some level of cellular control on the biomineralization process. This discovery expands the diversity of organisms capable of forming amorphous calcium carbonates.

  3. A primitive cyanobacterium as pioneer microorganism for terraforming Mars.

    PubMed

    Friedmann, E I; Ocampo-Friedmann, R

    1995-03-01

    The primitive characteristics of the cyanobacterium Chroococcidiopsis suggest that it represents a very ancient type of the group. Its morphology is simple but shows a wide range of variability, and it resembles certain Proterozoic microfossils. Chroococcidiopsis is probably the most desiccation-resistant cyanobacterium, the sole photosynthetic organism in extreme arid habitats. It is also present in a wide range of other extreme environments, from Antarctic rocks to thermal springs and hypersaline habitats, but it is unable to compete with more specialized organisms. Genetic evidence suggests that all forms belong to a single species. Its remarkable tolerance of environmental extremes makes Chroococcidiopsis a prime candidate for use as a pioneer photosynthetic microorganism for terraforming of Mars. The hypolithic microbial growth form (which lives under stones of a desert pavement) could be used as a model for development of technologies for large-scale Martian farming.

  4. An early-branching microbialite cyanobacterium forms intracellular carbonates.

    PubMed

    Couradeau, Estelle; Benzerara, Karim; Gérard, Emmanuelle; Moreira, David; Bernard, Sylvain; Brown, Gordon E; López-García, Purificación

    2012-04-27

    Cyanobacteria have affected major geochemical cycles (carbon, nitrogen, and oxygen) on Earth for billions of years. In particular, they have played a major role in the formation of calcium carbonates (i.e., calcification), which has been considered to be an extracellular process. We identified a cyanobacterium in modern microbialites in Lake Alchichica (Mexico) that forms intracellular amorphous calcium-magnesium-strontium-barium carbonate inclusions about 270 nanometers in average diameter, revealing an unexplored pathway for calcification. Phylogenetic analyses place this cyanobacterium within the deeply divergent order Gloeobacterales. The chemical composition and structure of the intracellular precipitates suggest some level of cellular control on the biomineralization process. This discovery expands the diversity of organisms capable of forming amorphous calcium carbonates.

  5. Ecology and Physiology of the Pathogenic Cyanobacterium Roseofilum reptotaenium

    PubMed Central

    Richardson, Laurie L.; Stanić, Dina; May, Amanda; Brownell, Abigael; Gantar, Miroslav; Campagna, Shawn R.

    2014-01-01

    Roseofilum reptotaenium is a gliding, filamentous, phycoerythrin-rich cyanobacterium that has been found only in the horizontally migrating, pathogenic microbial mat, black band disease (BBD) on Caribbean corals. R. reptotaenium dominates the BBD mat in terms of biomass and motility, and the filaments form the mat fabric. This cyanobacterium produces the cyanotoxin microcystin, predominately MC-LR, and can tolerate high levels of sulfide produced by sulfate reducing bacteria (SRB) that are also associated with BBD. Laboratory cultures of R. reptotaenium infect coral fragments, suggesting that the cyanobacterium is the primary pathogen of BBD, but since this species cannot grow axenically and Koch’s Postulates cannot be fulfilled, it cannot be proposed as a primary pathogen. However, R. reptotaenium does play several major pathogenic roles in this polymicrobial disease. Here, we provide an overview of the ecology of this coral pathogen and present new information on R. reptotaenium ecophysiology, including roles in the infection process, chemotactic and other motility responses, and the effect of pH on growth and motility. Additionally, we show, using metabolomics, that exposure of the BBD microbial community to the cyanotoxin MC-LR affects community metabolite profiles, in particular those associated with nucleic acid biosynthesis. PMID:25517133

  6. Bartolosides E-K from a Marine Coccoid Cyanobacterium.

    PubMed

    Afonso, Tiago B; Costa, M Sofia; Rezende de Castro, Roberta; Freitas, Sara; Silva, Artur; Schneider, Maria Paula Cruz; Martins, Rosário; Leão, Pedro N

    2016-10-28

    The glycosylated and halogenated dialkylresorcinol (DAR) compounds bartolosides A-D (1-4) were recently discovered from marine cyanobacteria and represent a novel family of glycolipids, encoded by the brt biosynthetic gene cluster. Here, we report the isolation and NMR- and MS-based structure elucidation of monoglycosylated bartolosides E-K (5-11), obtained from Synechocystis salina LEGE 06099, a strain closely related to the cyanobacterium that produces the diglycosylated 2-4. In addition, a genome region containing orthologues of brt genes was identified in this cyanobacterium. Interestingly, the major bartoloside in S. salina LEGE 06099 was 1 (above 0.5% dry wt), originally isolated from the phylogenetically distant filamentous cyanobacterium Nodosilinea sp. LEGE 06102. Compounds 5-11 are analogues of 1, with different alkyl chain lengths or halogenation patterns. Their structures and the organization of the brt genes suggest that the DAR-forming ketosynthase BrtD can generate structural diversity by accepting fatty acyl-derived substrates of varying length. Compound 9 features a rare midchain gem-dichloro moiety, indicating that the putative halogenase BrtJ is able to act twice on the same midchain carbon.

  7. Genotype × genotype interactions between the toxic cyanobacterium Microcystis and its grazer, the waterflea Daphnia

    PubMed Central

    Lemaire, Veerle; Brusciotti, Silvia; van Gremberghe, Ineke; Vyverman, Wim; Vanoverbeke, Joost; De Meester, Luc

    2012-01-01

    Toxic algal blooms are an important problem worldwide. The literature on toxic cyanobacteria blooms in inland waters reports widely divergent results on whether zooplankton can control cyanobacteria blooms or cyanobacteria suppress zooplankton by their toxins. Here we test whether this may be due to genotype × genotype interactions, in which interactions between the large-bodied and efficient grazer Daphnia and the widespread cyanobacterium Microcystis are not only dependent on Microcystis strain or Daphnia genotype but are specific to genotype × genotype combinations. We show that genotype × genotype interactions are important in explaining mortality in short-time exposures of Daphnia to Microcystis. These genotype × genotype interactions may result in local coadaptation and a geographic mosaic of coevolution. Genotype × genotype interactions can explain why the literature on zooplankton–cyanobacteria interactions is seemingly inconsistent, and provide hope that zooplankton can contribute to the suppression of cyanobacteria blooms in restoration projects. PMID:25568039

  8. COGNITIVE ECONOMICS

    PubMed Central

    KIMBALL, MILES

    2017-01-01

    Cognitive economics is the economics of what is in people’s minds. It is a vibrant area of research (much of it within behavioural economics, labour economics and the economics of education) that brings into play novel types of data, especially novel types of survey data. Such data highlight the importance of heterogeneity across individuals and highlight thorny issues for welfare economics. A key theme of cognitive economics is finite cognition (often misleadingly called “bounded rationality”), which poses theoretical challenges that call for versatile approaches. Cognitive economics brings a rich toolbox to the task of understanding a complex world. PMID:28149186

  9. COGNITIVE ECONOMICS.

    PubMed

    Kimball, Miles

    2015-06-01

    Cognitive economics is the economics of what is in people's minds. It is a vibrant area of research (much of it within behavioural economics, labour economics and the economics of education) that brings into play novel types of data, especially novel types of survey data. Such data highlight the importance of heterogeneity across individuals and highlight thorny issues for welfare economics. A key theme of cognitive economics is finite cognition (often misleadingly called "bounded rationality"), which poses theoretical challenges that call for versatile approaches. Cognitive economics brings a rich toolbox to the task of understanding a complex world.

  10. Identification and Regulation of Genes for Cobalamin Transport in the Cyanobacterium Synechococcus sp. Strain PCC 7002

    PubMed Central

    Pérez, Adam A.; Rodionov, Dmitry A.

    2016-01-01

    ABSTRACT The cyanobacterium Synechococcus sp. strain PCC 7002 is a cobalamin auxotroph and utilizes this coenzyme solely for the synthesis of l-methionine by methionine synthase (MetH). Synechococcus sp. strain PCC 7002 is unable to synthesize cobalamin de novo, and because of the large size of this tetrapyrrole, an active-transport system must exist for cobalamin uptake. Surprisingly, no cobalamin transport system was identified in the initial annotation of the genome of this organism. With more sophisticated in silico prediction tools, a btuB-cpdA-btuC-btuF operon encoding components putatively required for a B12 uptake (btu) system was identified. The expression of these genes was predicted to be controlled by a cobalamin riboswitch. Global transcriptional profiling by high-throughput RNA sequencing of a cobalamin-independent form of Synechococcus sp. strain PCC 7002 grown in the absence or presence of cobalamin confirmed regulation of the btu operon by cobalamin. Pérez et al. (A. A. Pérez, Z. Liu, D. A. Rodionov, Z. Li, and D. A. Bryant, J Bacteriol 198:2743–2752, 2016, http://dx.doi.org/10.1128/JB.00475-16) developed a cobalamin-dependent yellow fluorescent protein reporter system in a Synechococcus sp. strain PCC 7002 variant that had been genetically modified to allow cobalamin-independent growth. This reporter system was exploited to validate components of the btu uptake system by assessing the ability of targeted mutants to transport cobalamin. The btuB promoter and a variant counterpart mutated in an essential element of the predicted cobalamin riboswitch were fused to a yfp reporter. The combined data indicate that the btuB-cpdA-btuF-btuC operon in this cyanobacterium is transcriptionally regulated by a cobalamin riboswitch. IMPORTANCE With a cobalamin-regulated reporter system for expression of yellow fluorescent protein, genes previously misidentified as encoding subunits of a siderophore transporter were shown to encode components of cobalamin

  11. Draft Genome Sequence of Exopolysaccharide-Producing Cyanobacterium Aphanocapsa montana BDHKU 210001

    PubMed Central

    Bhattacharyya, Sourav; Chandrababunaidu, Mathu Malar; Sen, Deeya; Panda, Arijit; Ghorai, Arpita; Bhan, Sushma; Sanghi, Neha

    2015-01-01

    We report for the first time the draft genome sequence of Aphanocapsa montana BDHKU 210001, a halotolerant cyanobacterium isolated from India. This is a marine exopolysaccharide (EPS)-producing cyanobacterium. The genome of this species is assembled into 11.50 million bases, with 296 scaffolds carrying approximately 7,296 protein-coding genes. PMID:25744997

  12. Carotenoid composition in the cyanobacterium Phormidium laminosum. Effect of nitrogen starvation.

    PubMed

    Fresnedo, O; Gomez, R; Serra, J L

    1991-05-06

    When pigments of the non-N2-fixing cyanobacterium Phormidium laminosum were carefully extracted and analyzed in a completely O2-free atmosphere, by either high performance liquid chromatography (HPLC) or thin layer chromatography (TLC), the presence of only two carotenoids (namely, beta-carotene and nostoxanthin) was detected. However, exposure of pigments to an air atmosphere during their manipulation led to the rapid appearance in the organic extracts of at least three additional carotenoids (identified as caloxanthin, zeaxanthin and beta-cryptoxanthin). This fact could explain the presence in cyanobacteria of such hydroxylated derivatives of beta-carotene widely reported in the literature. Nitrogen starvation also resulted in an important decrease on the relative beta-carotene/nostoxanthin content of cells, suggesting that this nutritional condition affects thylakoid membranes more drastically than cytoplasmic membranes.

  13. Utilization of a terrestrial cyanobacterium, Nostoc sp. HK-01, for space habitation

    NASA Astrophysics Data System (ADS)

    Kimura, Shunta; Tomita-Yokotani, Kaori; Arai, Mayumi; Yamashita, Masamichi; Katoh, Hiroshi; Ajioka, Reiko; Inoue, Kotomi

    2016-07-01

    A terrestrial cyanobacterium, Nostoc sp. HK-01 (hereafter HK-01), has several useful abilities for space habitation; photosynthesis, nitrogen fixation, and space environmental tolerances to vacuum, UV, gamma-ray, heavy particle beam, low and high temperature. Space environmental tolerances are important for transportation to Mars. HK-01 can grow on Martian regolith simulant (MRS) in vitro. Furthermore, HK-01 is useful as food. HK-01 may be utilized as oxygen supply, soil formation and food material for bio-chemical circulation in closed bio-ecosystems, including space habitation such as Mars. HK-01 was adopted as a biological material for the "TANPOPO" mission (JAXA et al.,), because of their high environmental tolerances. The "TANPOPO" mission is performing the space exposure experiments on the Japan Experimental Module (JEM) of the International Space Station (ISS). The results of these experiments will show the ability of HK-01 to survive in space.

  14. Major Role of the Cyanobacterium Trichodesmium in Nutrient Cycling in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Carpenter, Edward J.; Romans, Kristen

    1991-11-01

    The diazotrophic cyanobacterium Trichodesmium is a large (about 0.5 by 3 millimeters) phytoplankter that is common in tropical open-ocean waters. Measurements of abundance, plus a review of earlier observations, indicate that it, rather than the picophytoplankton, is the most important primary producer (about 165 milligrams of carbon per square meter per day) in the tropical North Atlantic Ocean. Furthermore, nitrogen fixation by Trichodesmium introduces the largest fraction of new nitrogen to the euphotic zone, approximately 30 milligrams of nitrogen per square meter per day, a value exceeding the estimated flux of nitrate across the thermocline. Inclusion of this organism, plus the abundant diazotrophic endosymbiont Richelia intracellularis that is present in some large diatoms, in biogeochemical studies of carbon and nitrogen may help explain the disparity between various methods of measuring productivity in the oligotrophic ocean. Carbon and nitrogen fixation by these large phytoplankters also introduces a new paradigm in the biogeochemistry of these elements in the sea.

  15. Live Cell Chemical Profiling of Temporal Redox Dynamics in a Photoautotrophic Cyanobacterium

    SciTech Connect

    Sadler, Natalie C.; Melnicki, Matthew R.; Serres, Margrethe H.; Merkley, Eric D.; Chrisler, William B.; Hill, Eric A.; Romine, Margaret F.; Kim, Sangtae; Zink, Erika M.; Datta, Suchitra; Smith, Richard D.; Beliaev, Alex S.; Konopka, Allan; Wright, Aaron T.

    2014-01-01

    Protein reduction-oxidation (redox) modification is an important mechanism that allows microorganisms to sense environmental changes and initiate cellular responses. We have developed a quantitative chemical probe approach for live cell labeling of proteins that are sensitive to redox modifications. We utilize this in vivo strategy to identify 176 proteins undergoing ~5-10 fold dynamic redox change in response to nutrient limitation and subsequent replenishment in the photoautotrophic cyanobacterium, Synechococcus sp. PCC 7002. We detect redox changes in as little as 30 seconds after nutrient perturbation, and oscillations in reduction and oxidation for 60 minutes following the perturbation. Many of the proteins undergoing dynamic redox transformations participate in the major components for the production (photosystems and electron transport chains) or consumption (Calvin-Benson cycle and protein synthesis) of reductant and/or energy in photosynthetic organisms. Thus, our in vivo approach reveals new redox-susceptible proteins, in addition to validating those previously identified in vitro.

  16. Oxidative stress management in the filamentous, heterocystous, diazotrophic cyanobacterium, Anabaena PCC7120.

    PubMed

    Banerjee, Manisha; Raghavan, Prashanth S; Ballal, Anand; Rajaram, Hema; Apte, S K

    2013-10-10

    Reactive oxygen species (ROS) are inevitably generated as by-products of respiratory/photosynthetic electron transport in oxygenic photoautotrophs. Unless effectively scavenged, these ROS can damage all cellular components. The filamentous, heterocystous, nitrogen-fixing strains of the cyanobacterium, Anabaena, serve as naturally abundant contributors of nitrogen biofertilizers in tropical rice paddy fields. Anabaena strains are known to tolerate several abiotic stresses, such as heat, UV, gamma radiation, desiccation, etc., that are known to generate ROS. ROS are detoxified by specific antioxidant enzymes like superoxide dismutases (SOD), catalases and peroxiredoxins. The genome of Anabaena PCC7120 encodes two SODs, two catalases and seven peroxiredoxins, indicating the presence of an elaborate antioxidant enzymatic machinery to defend its cellular components from ROS. This article summarizes recent findings and depicts important perspectives in oxidative stress management in Anabaena PCC7120.

  17. Ocean acidification adversely influences metabolism, extracellular pH and calcification of an economically important marine bivalve, Tegillarca granosa.

    PubMed

    Zhao, Xinguo; Shi, Wei; Han, Yu; Liu, Saixi; Guo, Cheng; Fu, Wandong; Chai, Xueliang; Liu, Guangxu

    2017-04-01

    Oceanic uptake of CO2 from the atmosphere has significantly reduced surface seawater pH and altered the carbonate chemistry within, leading to global Ocean Acidification (OA). The blood clam, Tegillarca granosa, is an economically and ecologically significant marine bivalve that is widely distributed along the coastal and estuarine areas of Asia. To investigate the physiological responses to OA, blood clams were exposed to ambient and three reduced seawater pH levels (8.1, 7.8, 7.6 and 7.4) for 40 days, respectively. Results obtained suggest that OA suppresses the feeding activity and aerobic metabolism, but elevates proteins catabolism of blood clams. OA also causes extracellular acidosis and decreases haemolymph Ca(2+) concentration. In addition, our data also suggest that OA impairs the calcification process and inner shell surface integrity. Overall, OA adversely influences metabolism, acid-base status and calcification of blood clams, subsequently leading to a decrease in the fitness of this marine bivalve species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The importance of socio-economic status and individual characteristics on the prevalence of head lice in schoolchildren.

    PubMed

    Willems, Sara; Lapeere, Hilde; Haedens, Nele; Pasteels, Inge; Naeyaert, Jean-Marie; De Maeseneer, Jan

    2005-01-01

    Pediculosis is a common infestation in schoolchildren but little is known about the factors influencing its prevalence. The aim of this study was to determine the prevalence of head lice in schoolchildren in Ghent and to investigate the independent association between individual characteristics of the child, socio-economic status (SES) of the family and head lice. The prevalence of head lice at baseline and 14 days after treatment advice was determined by the wet combing method in a total of 6,169 schoolchildren age 2.5 to 12 years from Ghent (Belgium). Age, sex, educational level and hair characteristics of the child, SES of the family, and number of children in the family was collected by the school health department. The prevalence of head lice was 8.9%. The only statistically significant factors at the child level are SES, the number of children in the family, hair length and hair colour. Treatment failure was recorded in 41% of the children positive at baseline screening and was significantly related to hair colour and SES. This study demonstrated that the prevalence of head lice is determined by clustering of children rather than by characteristics of the child. The management of head lice should take a community-based approach equally involving families, schools, health care professionals and the government.

  19. Designing and creating a modularized synthetic pathway in cyanobacterium Synechocystis enables production of acetone from carbon dioxide.

    PubMed

    Zhou, Jie; Zhang, Haifeng; Zhang, Yanping; Li, Yin; Ma, Yanhe

    2012-07-01

    Ketones are a class of important organic compounds. As the simplest ketone, acetone is widely used as solvents or precursors for industrial chemicals. Presently, million tonnes of acetone is produced worldwide annually, from petrochemical processes. Here we report a biotechnological process that can produce acetone from CO(2), by designing and creating a modularized synthetic pathway in engineered cyanobacterium Synechocystis sp. PCC 6803. The engineered Synechocystis cells are able to produce acetone (36.0 mgl(-1) culture medium) using CO(2) as the sole carbon source, thus opens the gateway for biosynthesis of ketones from CO(2).

  20. 50 CFR 14.33 - Permits to import or export wildlife at nondesignated port to alleviate undue economic hardship.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING, POSSESSION, TRANSPORTATION, SALE... description of the form in which it is to be imported, such as “live,” “frozen,” “raw hides,” or a full description of any manufactured product; (2) The country or place in which the wildlife was removed from the...

  1. 77 FR 34781 - Importation of Tomatoes From the Economic Community of West African States Into the Continental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-12

    ... systems approach that includes requirements for pest exclusion at the production site, fruit fly trapping... importation of tomatoes from various countries where the Mediterranean fruit fly (Medfly, Ceratitis capitata..., fruit fly trapping and monitoring, and procedures for packing the tomatoes. We also proposed to require...

  2. Chemokinetic motility responses of the cyanobacterium oscillatoria terebriformis

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Castenholz, Richard W.

    1989-01-01

    Oscillatoria terebriformis, a gliding, filamentous, thermophilic cyanobacterium, exhibited an inhibition of gliding motility upon exposure to fructose. The observed response was transient, and the duration of nonmotility was directly proportional to the concentration of fructose. Upon resumption of motility, the rate of motility was also inversely proportional to the concentration of fructose. Sulfide caused a similar response. The effect of sulfide was specific and not due to either anoxia or negative redox potential. Exposure to glucose, acetate, lactate, or mat interstitial water did not elicit any motility response.

  3. Hapalindole-related Alkaloids from the Cultured Cyanobacterium Fischerella ambigua

    PubMed Central

    Mo, Shunyan; Krunic, Aleksej; Santarsiero, Bernard D.; Franzblau, Scott G.; Orjala, Jimmy

    2010-01-01

    Four new hapalindole-related alkaloids, namely fischambiguines A and B, ambiguine P, ambiguine Q nitrile as well as ambiguine G nitrile were identified from the cultured cyanobacterium Fischerella ambigua (UTEX 1903). The structures were determined by spectroscopic analysis including MS, 1D and 2D NMR and X-ray crystallography. The alkaloids possessed fused penta- and hexacyclic carbon skeletons. Fischambiguine B displayed a strong inhibitory activity against Mycobacterium tuberculosis with an MIC value of 2 μM, with no detectable cytotoxicity in a Vero cell line. PMID:20965528

  4. Chemokinetic motility responses of the cyanobacterium oscillatoria terebriformis

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Castenholz, Richard W.

    1989-01-01

    Oscillatoria terebriformis, a gliding, filamentous, thermophilic cyanobacterium, exhibited an inhibition of gliding motility upon exposure to fructose. The observed response was transient, and the duration of nonmotility was directly proportional to the concentration of fructose. Upon resumption of motility, the rate of motility was also inversely proportional to the concentration of fructose. Sulfide caused a similar response. The effect of sulfide was specific and not due to either anoxia or negative redox potential. Exposure to glucose, acetate, lactate, or mat interstitial water did not elicit any motility response.

  5. Transcriptomic Analysis and Microscopic Observations in the Cyanobacterium UCYN-A during Diel Cycles

    NASA Astrophysics Data System (ADS)

    Muñoz-Marin, M. D. C.; Farnelid, H.; Zehr, J. P.

    2016-02-01

    Candidatus Atelocyanobacterium thalassa (UCYN-A) is a nitrogen-fixing marine cyanobacterium recently recognized for its widespread distribution and significant contributions to oceanic nitrogen (N2)-fixation. UCYN-A is a group of related cyanobacteria that are symbiotic with a single-celled eukaryotic phytoplankter, the haptophyte Braarudosphaera bigelowii. UCYN-A fixes N2 and expresses nitrogenase during the day. Since the nitrogenase is inactivated by oxygen evolved through photosynthesis, most cyanobacteria use temporal or spatial separation of photosynthesis and N2 fixation. Genomic studies revealed that UCYN-A lacks the entire PSII apparatus (photosystem II). The lack of oxygenic photosynthesis at least partially explains why they can fix nitrogen during the day, although the host is a photoautotroph. However, UCYN-A has retained photosystem I (PSI), and PSI activity may be important in the energetics of N2 fixation in the symbiosis. Because UCYN-A lacks photosystem II, which normally supplies electrons to photosystem I from water, UCYN-A needs alternative electron donors if it uses photosystem I to make the reductant NADPH. In order to determine if UCYN-A expresses photosynthetic genes and which other proteins may be involved with energy metabolism, we developed a whole genome array to examine gene transcription over the diel cycle in two strains. Our results show that there is a temporal separation of the expression of photosynthesis genes from the expression of nitrogenase genes. Moreover, the transcription profile of NADH dehydrogenases and hydrogenases suggest they may be involved as alternative electron donors for the N2 fixation. In addition, we used a double-CARD-FISH (Catalyzed Reporter Deposition-Fluorescence in situ Hybridization) assay to study cell division of the host and symbiont during diel cycles in relation to UCYN-A gene expression carried out during the transcriptomic analysis. These results help us move toward a deeper understanding of the

  6. Transcriptomic Responses in the Bloom-Forming Cyanobacterium Microcystis Induced during Exposure to Zooplankton

    PubMed Central

    Harke, Matthew J.; Jankowiak, Jennifer G.; Morrell, Brooke K.

    2016-01-01

    ABSTRACT The bloom-forming, toxic cyanobacterium Microcystis synthesizes multiple secondary metabolites and has been shown to deter zooplankton grazing. However, the biochemical and/or molecular basis by which Microcystis deters zooplankton remains unclear. This global transcriptomic study explored the response of Microcystis to direct and indirect exposures to multiple densities of two cladoceran grazers, Daphnia pulex and D. magna. Higher densities of both daphnids significantly reduced Microcystis cell densities and elicited a stronger transcriptional response in Microcystis. While many putative grazer deterrence genes (encoding microcystin, aeruginosin, cyanopeptolin, and microviridin) were largely unaffected by zooplankton, transcripts for heat shock proteins (hsp) increased in abundance. Beyond metabolites and hsp, large increases in the abundances of transcripts from photosynthetic processes were observed, evidencing energy acquisition pathways were stimulated by grazing. In addition, transcripts of genes associated with the production of extracellular polysaccharides and gas vesicles significantly increased in abundance. These genes have been associated with colony formation and may have been invoked to deter grazers. Collectively, this study demonstrates that daphnid grazers induce a significant transcriptomic response in Microcystis, suggesting this cyanobacterium upregulates specific biochemical pathways to adapt to predation. IMPORTANCE This work explores the transcriptomic responses of Microcystis aeruginosa following exposure to grazing by two cladocerans, Daphnia magna and D. pulex. Contrary to previous hypotheses, Microcystis did not employ putative grazing deterrent secondary metabolites in response to the cladocerans, suggesting they may have other roles within the cell, such as oxidative stress protection. The transcriptional metabolic signature during intense grazing was largely reflective of a growth and stress response, although increasing

  7. The importance of socio-economic context for social marketing models for improving reproductive health: Evidence from 555 years of program experience

    PubMed Central

    Meekers, Dominique; Rahaim, Stephen

    2005-01-01

    Background Over the past two decades, social marketing programs have become an important element of the national family planning and HIV prevention strategy in several developing countries. As yet, there has not been any comprehensive empirical assessment to determine which of several social marketing models is most effective for a given socio-economic context. Such an assessment is urgently needed to inform the design of future social marketing programs, and to avoid that programs are designed using an ineffective model. Methods This study addresses this issue using a database of annual statistics about reproductive health oriented social marketing programs in over 70 countries. In total, the database covers 555 years of program experience with social marketing programs that distribute and promote the use of oral contraceptives and condoms. Specifically, our analysis assesses to what extent the model used by different reproductive health social marketing programs has varied across different socio-economic contexts. We then use random effects regression to test in which socio-economic context each of the models is most successful at increasing use of socially marketed oral contraceptives and condoms. Results The results show that there has been a tendency to design reproductive health social marketing program with a management structure that matches the local context. However, the evidence also shows that this has not always been the case. While socio-economic context clearly influences the effectiveness of some of the social marketing models, program maturity and the size of the target population appear equally important. Conclusions To maximize the effectiveness of future social marketing programs, it is essential that more effort is devoted to ensuring that such programs are designed using the model or approach that is most suitable for the local context. PMID:15676068

  8. The importance of socio-economic context for social marketing models for improving reproductive health: evidence from 555 years of program experience.

    PubMed

    Meekers, Dominique; Rahaim, Stephen

    2005-01-27

    Over the past two decades, social marketing programs have become an important element of the national family planning and HIV prevention strategy in several developing countries. As yet, there has not been any comprehensive empirical assessment to determine which of several social marketing models is most effective for a given socio-economic context. Such an assessment is urgently needed to inform the design of future social marketing programs, and to avoid that programs are designed using an ineffective model. This study addresses this issue using a database of annual statistics about reproductive health oriented social marketing programs in over 70 countries. In total, the database covers 555 years of program experience with social marketing programs that distribute and promote the use of oral contraceptives and condoms. Specifically, our analysis assesses to what extent the model used by different reproductive health social marketing programs has varied across different socio-economic contexts. We then use random effects regression to test in which socio-economic context each of the models is most successful at increasing use of socially marketed oral contraceptives and condoms. The results show that there has been a tendency to design reproductive health social marketing program with a management structure that matches the local context. However, the evidence also shows that this has not always been the case. While socio-economic context clearly influences the effectiveness of some of the social marketing models, program maturity and the size of the target population appear equally important. To maximize the effectiveness of future social marketing programs, it is essential that more effort is devoted to ensuring that such programs are designed using the model or approach that is most suitable for the local context.

  9. The impact of past introductions on an iconic and economically important species, the red deer of Scotland.

    PubMed

    Pérez-Espona, Sílvia; Hall, Richard J; Pérez-Barbería, F Javier; Glass, Belinda C; Ward, Jamie F; Pemberton, Josephine M

    2013-01-01

    The red deer (Cervus elaphus) is an iconic species in Scotland and, due to its value as a game species, an important element of the Scottish rural economy. The native status of this species is sometimes questioned because of many recorded introductions of nonnative deer in the past that were an attempt to improve trophy size. In this study, we assessed the impact of past introductions on the genetic makeup of Scottish red deer by genotyping at 15 microsatellite loci a large number of samples (n = 1152), including mainland and island Scottish red deer and individuals from several putative external source populations used in introductions to improve trophy size. Population structure and introgression assessment analyses revealed that the impact of introductions was weak in Highland red deer populations but more prominent on the islands, especially on those where current red deer populations are mostly or entirely derived from introductions (Harris & Lewis, Arran, and Rum). Frequent imports of Central-Eastern European red deer into English deer parks were reflected in the higher genetic introgression values found in some of the individuals collected in parks.

  10. Diurnal Regulation of Cellular Processes in the Cyanobacterium Synechocystis sp. Strain PCC 6803: Insights from Transcriptomic, Fluxomic, and Physiological Analyses.

    PubMed

    Saha, Rajib; Liu, Deng; Hoynes-O'Connor, Allison; Liberton, Michelle; Yu, Jingjie; Bhattacharyya-Pakrasi, Maitrayee; Balassy, Andrea; Zhang, Fuzhong; Moon, Tae Seok; Maranas, Costas D; Pakrasi, Himadri B

    2016-05-03

    Synechocystis sp. strain PCC 6803 is the most widely studied model cyanobacterium, with a well-developed omics level knowledgebase. Like the lifestyles of other cyanobacteria, that of Synechocystis PCC 6803 is tuned to diurnal changes in light intensity. In this study, we analyzed the expression patterns of all of the genes of this cyanobacterium over two consecutive diurnal periods. Using stringent criteria, we determined that the transcript levels of nearly 40% of the genes in Synechocystis PCC 6803 show robust diurnal oscillating behavior, with a majority of the transcripts being upregulated during the early light period. Such transcripts corresponded to a wide array of cellular processes, such as light harvesting, photosynthetic light and dark reactions, and central carbon metabolism. In contrast, transcripts of membrane transporters for transition metals involved in the photosynthetic electron transport chain (e.g., iron, manganese, and copper) were significantly upregulated during the late dark period. Thus, the pattern of global gene expression led to the development of two distinct transcriptional networks of coregulated oscillatory genes. These networks help describe how Synechocystis PCC 6803 regulates its metabolism toward the end of the dark period in anticipation of efficient photosynthesis during the early light period. Furthermore, in silico flux prediction of important cellular processes and experimental measurements of cellular ATP, NADP(H), and glycogen levels showed how this diurnal behavior influences its metabolic characteristics. In particular, NADPH/NADP(+) showed a strong correlation with the majority of the genes whose expression peaks in the light. We conclude that this ratio is a key endogenous determinant of the diurnal behavior of this cyanobacterium. Cyanobacteria are photosynthetic microbes that use energy from sunlight and CO2 as feedstock. Certain cyanobacterial strains are amenable to facile genetic manipulation, thus enabling

  11. Diurnal Regulation of Cellular Processes in the Cyanobacterium Synechocystis sp. Strain PCC 6803: Insights from Transcriptomic, Fluxomic, and Physiological Analyses

    PubMed Central

    Saha, Rajib; Liu, Deng; Hoynes-O’Connor, Allison; Liberton, Michelle; Yu, Jingjie; Bhattacharyya-Pakrasi, Maitrayee; Balassy, Andrea; Zhang, Fuzhong; Maranas, Costas D.

    2016-01-01

    ABSTRACT Synechocystis sp. strain PCC 6803 is the most widely studied model cyanobacterium, with a well-developed omics level knowledgebase. Like the lifestyles of other cyanobacteria, that of Synechocystis PCC 6803 is tuned to diurnal changes in light intensity. In this study, we analyzed the expression patterns of all of the genes of this cyanobacterium over two consecutive diurnal periods. Using stringent criteria, we determined that the transcript levels of nearly 40% of the genes in Synechocystis PCC 6803 show robust diurnal oscillating behavior, with a majority of the transcripts being upregulated during the early light period. Such transcripts corresponded to a wide array of cellular processes, such as light harvesting, photosynthetic light and dark reactions, and central carbon metabolism. In contrast, transcripts of membrane transporters for transition metals involved in the photosynthetic electron transport chain (e.g., iron, manganese, and copper) were significantly upregulated during the late dark period. Thus, the pattern of global gene expression led to the development of two distinct transcriptional networks of coregulated oscillatory genes. These networks help describe how Synechocystis PCC 6803 regulates its metabolism toward the end of the dark period in anticipation of efficient photosynthesis during the early light period. Furthermore, in silico flux prediction of important cellular processes and experimental measurements of cellular ATP, NADP(H), and glycogen levels showed how this diurnal behavior influences its metabolic characteristics. In particular, NADPH/NADP+ showed a strong correlation with the majority of the genes whose expression peaks in the light. We conclude that this ratio is a key endogenous determinant of the diurnal behavior of this cyanobacterium. PMID:27143387

  12. Seasonal change in main alkaloids of jaborandi (Pilocarpus microphyllus Stapf ex Wardleworth), an economically important species from the Brazilian flora

    PubMed Central

    Véras, Leiz Maria Costa; Azevedo, Iábita Fabiana Sousa; Biase, Adriele Giaretta; Costa, Joana; Oliveira, Maria Beatriz P. P.; Mafra, Isabel

    2017-01-01

    Pilocarpus microphyllus Stapf ex Wardleworth (jaborandi, Rutaceae) is one of the most important Brazilian medicinal species owing to its content of pilocarpine (PIL), an alkaloid used for treating glaucoma and xerostomia. This species contains another alkaloid, epiisopiloturine (EPI), which has demonstrated effectiveness against schistosomiasis. The aim of this work was to assess seasonal changes of PIL and EPI in three populations of cultivated P. microphyllus from northeastern Brazil over one year, including the dry and rainy seasons. Alkaloid profiles were correlated to phenotypic and genetic patterns in the morphological and molecular characterizations. PIL was the primary alkaloid and its levels differed among populations in all months except September. The S01 population (green line) showed an especially high PIL content compared to populations S02 and S03 (traditional line), which had similar alkaloid contents. PIL content gradually decreased in the three populations in the rainy season.EPI content was significantly different between the green line (S01) and the traditional line (S02 and S03).S01 had a significantly lower EPI content in all months, demonstrating that it was not the best source for EPI extraction. Inter simple sequence repeat (ISSR) markers and morphological analyses clearly separated S01 from S02 and S03, in agreement with the alkaloid results. This study shows the first correlation between the chemical, morphological, and molecular markers of P. microphyllus and highlights the potential benefits of a multidisciplinary research approach aimed at supporting both industry and conservation of natural resources. PMID:28151972

  13. Searching for new loci and candidate genes for economically important traits through gene-based association analysis of Simmental cattle

    PubMed Central

    Xia, Jiangwei; Fan, Huizhong; Chang, Tianpeng; Xu, Lingyang; Zhang, Wengang; Song, Yuxin; Zhu, Bo; Zhang, Lupei; Gao, Xue; Chen, Yan; Li, Junya; Gao, Huijiang

    2017-01-01

    Single-marker genome-wide association study (GWAS) is a convenient strategy of genetic analysis that has been successful in detecting the association of a number of single-nucleotide polymorphisms (SNPs) with quantitative traits. However, analysis of individual SNPs can only account for a small proportion of genetic variation and offers only limited knowledge of complex traits. This inadequacy may be overcome by employing a gene-based GWAS analytic approach, which can be considered complementary to the single-SNP association analysis. Here we performed an initial single-SNP GWAS for bone weight (BW) and meat pH value with a total of 770,000 SNPs in 1141 Simmental cattle. Additionally, 21836 cattle genes collected from the Ensembl Genes 83 database were analyzed to find supplementary evidence to support the importance of gene-based association study. Results of the single SNP-based association study showed that there were 11 SNPs significantly associated with bone weight (BW) and two SNPs associated with meat pH value. Interestingly, all of these SNPs were located in genes detected by the gene-based association study. PMID:28169328

  14. [History and economic importance of cattle (Bos taurus L.) in Switzerland from Neolithic to Early Middle Ages].

    PubMed

    Schibler, J; Schlumbaum, A

    2007-01-01

    In Switzerland domestic cattle (Bos primigenius f. taurus resp. Bos taurus L.) first appear with the earliest Neolithic settlements (approximately 5000 BC). With the gradual deforestation of the landscape caused by human exploitation of the environment, cattle were used more intensive and in many ways. There is evidence that cattle were used as draught animal since ca. 3400 BC, probably even earlier milk was regularly used. The size of domestic cattle gradually decreased from Early Neolithic until Iron Age. Only with Roman influence larger animals are found. However, after the withdrawal of Romans the average size of cattle decreased again. Archaeogenetic studies will have to show, whether this is due to novel breeding strategies or the import of breeding stock. First genetic results showed that a female genetic type, which is rare in European breeds, is present in Swiss Evolène cattle and in one animal of Roman time cattle from Augusta Raurica. Is this a sign for influence of Roman cattle on today's Swiss breeds?

  15. Seasonal change in main alkaloids of jaborandi (Pilocarpus microphyllus Stapf ex Wardleworth), an economically important species from the Brazilian flora.

    PubMed

    Lima, David Fernandes; de Lima, Luiza Ianny; Rocha, Jefferson Almeida; de Andrade, Ivanilza Moreira; Grazina, Liliana Gonçalves; Villa, Caterina; Meira, Liliana; Véras, Leiz Maria Costa; Azevedo, Iábita Fabiana Sousa; Biase, Adriele Giaretta; Costa, Joana; Oliveira, Maria Beatriz P P; Mafra, Isabel; Leite, José Roberto de Souza de Almeida

    2017-01-01

    Pilocarpus microphyllus Stapf ex Wardleworth (jaborandi, Rutaceae) is one of the most important Brazilian medicinal species owing to its content of pilocarpine (PIL), an alkaloid used for treating glaucoma and xerostomia. This species contains another alkaloid, epiisopiloturine (EPI), which has demonstrated effectiveness against schistosomiasis. The aim of this work was to assess seasonal changes of PIL and EPI in three populations of cultivated P. microphyllus from northeastern Brazil over one year, including the dry and rainy seasons. Alkaloid profiles were correlated to phenotypic and genetic patterns in the morphological and molecular characterizations. PIL was the primary alkaloid and its levels differed among populations in all months except September. The S01 population (green line) showed an especially high PIL content compared to populations S02 and S03 (traditional line), which had similar alkaloid contents. PIL content gradually decreased in the three populations in the rainy season.EPI content was significantly different between the green line (S01) and the traditional line (S02 and S03).S01 had a significantly lower EPI content in all months, demonstrating that it was not the best source for EPI extraction. Inter simple sequence repeat (ISSR) markers and morphological analyses clearly separated S01 from S02 and S03, in agreement with the alkaloid results. This study shows the first correlation between the chemical, morphological, and molecular markers of P. microphyllus and highlights the potential benefits of a multidisciplinary research approach aimed at supporting both industry and conservation of natural resources.

  16. [Yellow fever in the Ribeirão Preto region at the turn of the 19th century: its scientific importance and economic repercussions].

    PubMed

    Figueiredo, L T

    1996-01-01

    Yellow fever in the Region of Ribeirao Preto at the turn of XIX century: scientific importance and economic repercussion. This historical review describes the bad situation of public health in Brazil during the XIX Century caused by multiple yellow fever outbreaks. The knowledge regarding to yellow fever at that time is also described. A short history is presented of the development of the Region of Ribeirao Preto, located in the Northeast of Sao Paulo State, Brazil, emphasising the actuation of immigrants and pioneer coffee farmers like Luiz Pereira Barreto. Yellow fever outbreaks occurred in the City of Sao Simao in 1896, 1898, and 1902 are described as well as an outbreak in the City of Ribeirao Preto occurring in 1903. It is shown that yellow fever outbreaks were stopped in the 2 cities by Emilio Ribas who led the fight against the transmitting mosquito Aedes aegypti. Emilio Ribas, helped by Adolpho, Lutz and Luiz Pereira Barreto, promoted scientific experiments in order to confirm the vectorial transmission of yellow fever and to annul the supposed importance of other kinds of contagion. The yellow fever outbreaks caused damage to the development of Sao Simao and influenced the transference of the economic pole of the region to the City of Ribeirao Preto. The vector control work done during yellow fever outbreak and the scientific experiments on the transmission of yellow fever were important for the development of medical science and fpublic health in Brazil.

  17. The freshwater cyanobacterium Anabaena doliolum transformed with ApGSMT-DMT exhibited enhanced salt tolerance and protection to nitrogenase activity, but became halophilic.

    PubMed

    Singh, Meenakshi; Sharma, Naveen K; Prasad, Shyam Babu; Yadav, Suresh Singh; Narayan, Gopeshwar; Rai, Ashwani K

    2013-03-01

    Glycine betaine (GB) is an important osmolyte synthesized in response to different abiotic stresses, including salinity. The two known pathways of GB synthesis involve: 1) two step oxidation of choline (choline → betaine aldehyde → GB), generally found in plants, microbes and animals; and 2) three step methylation of glycine (glycine → sarcosine → dimethylglycine → GB), mainly found in halophilic archaea, sulphur bacteria and the cyanobacterium Aphanothece (Ap.) halophytica. Here, we transformed a salt-sensitive freshwater diazotrophic filamentous cyanobacterium Anabaena (An.) doliolum with N-methyltransferase genes (ApGSMT-DMT) from Ap. halophytica using the triparental conjugation method. The transformed An. doliolum synthesized and accumulated GB in cells, and showed increased salt tolerance and protection to nitrogenase activity. The salt responsiveness of the transformant was also apparent as GB synthesis increased with increasing concentrations of NaCl in the nutrient solution, and maximal [12.92 µmol (g dry weight)(-1)] in cells growing at 0.5 M NaCl. Therefore, the transformed cyanobacterium has changed its behaviour from preferring freshwater to halophily. This study may have important biotechnological implications for the development of stress tolerant nitrogen-fixing cyanobacteria as biofertilizers for sustainable agriculture.

  18. Prevalence of SGHV among tsetse species of economic importance in Tanzania and their implication for SIT application.

    PubMed

    Malele, Imna I; Manangwa, Oliver; Nyingilili, Hamisi H; Kitwika, Winston A; Lyaruu, Eugene A; Msangi, Atway R; Ouma, Johnson O; Nkwangulila, Gamba; Abd-Alla, Adly M M

    2013-03-01

    Sterile Insect technique is an important component in area-wide integrated tsetse control. The presence of the salivary glands hypertrophy virus (SGHV) in the wild tsetse, which are the seeds for colony adaptations in the laboratory has become a stumbling block in establishing and maintaining colonies in the laboratory. The virus is transmitted both vertically (in the wild) and horizontally (in the laboratory). However, its prevalence is magnified in the laboratory as a result of the use of in vitro membrane feeding regimen. Fly species of Glossina fuscipes fuscipes, G. pallidipes, G. morsitans and G. swynnertoni were collected from the coastal and inland areas of Tanzania and virus infection rates were assessed microscopically and by PCR. The data showed that in a period of 4years, the virus was present in all species tested irrespective of their ages, sex, and season of the year. However, infection levels differed among species and from one location to another. Symptomatic infection determined by dissection was 1.2% (25/2164) from the coast as compared to 0.4% (6/1725) for inland collected flies. PCR analysis indicated a higher infection rate of 19.81% (104/525) of asymptomatic flies. From these observations, we conclude that care should be taken when planning to initiate tsetse laboratory colonies for use in SIT eradication program. All efforts should be made to select non-infected flies when initiating laboratory colonies and to try to minimize the infection with SGHV. Also management of SGHV infection in the established colony should be applied.

  19. Influence of physico-chemical properties on the abundance of a few economically important juvenile fin-fishes of Vellar estuary.

    PubMed

    Brinda, S; Bragadeeswaran, S

    2005-01-01

    Studies on the economically important juvenile fin-fishes such as Elops machnata, Chanos chanos, Lates calcarifer, Epinephelus sp., Sillago sihama, Etroplus suratensis, Mugil cephalus, Liza parsia and Liza tade with relation to the hydrographical parameters as rainfall, temperature, salinity, dissolved oxygen and pH of Vellar estuary during September 2001 to August 2002. The simple correlation co-efficient showed positive significance against juvenile density with water temperature and dissolved oxygen. The influence of hydrographical parameters to the fin-fishes and its abundance is discussed.

  20. Worst-Case Scenario Tsunami Hazard Assessment in Two Historically and Economically Important Districts in Eastern Sicily (Italy)

    NASA Astrophysics Data System (ADS)

    Armigliato, A.; Tinti, S.; Pagnoni, G.; Zaniboni, F.; Paparo, M. A.

    2015-12-01

    The portion of the eastern Sicily coastline (southern Italy), ranging from the southern part of the Catania Gulf (to the north) down to the southern-eastern end of the island, represents a very important geographical domain from the industrial, commercial, military, historical and cultural points of view. Here the two major cities of Augusta and Siracusa are found. In particular, the Augusta bay hosts one of the largest petrochemical poles in the Mediterranean, and Siracusa is listed among the UNESCO World Heritage Sites since 2005. This area was hit by at least seven tsunamis in the approximate time interval from 1600 BC to present, the most famous being the 365, 1169, 1693 and 1908 tsunamis. The choice of this area as one of the sites for the testing of innovative methods for tsunami hazard, vulnerability and risk assessment and reduction is then fully justified. This is being developed in the frame of the EU Project called ASTARTE - Assessment, STrategy And Risk Reduction for Tsunamis in Europe (Grant 603839, 7th FP, ENV.2013.6.4-3). We assess the tsunami hazard for the Augusta-Siracusa area through the worst-case credible scenario technique, which can be schematically divided into the following steps: 1) Selection of five main source areas, both in the near- and in the far-field (Hyblaean-Malta escarpment, Messina Straits, Ionian subduction zone, Calabria offshore, western Hellenic Trench); 2) Choice of potential and credible tsunamigenic faults in each area: 38 faults were selected, with properly assigned magnitude, geometry and focal mechanism; 3) Computation of the maximum tsunami wave elevations along the eastern Sicily coast on a coarse grid (by means of the in-house code UBO-TSUFD) and extraction of the 9 scenarios that produce the largest effects in the target areas of Augusta and Siracusa; 4) For each of the 9 scenarios we run numerical UBO-TSUFD simulations over a set of five nested grids, with grid cells size decreasing from 3 km in the open Ionian

  1. A reference consensus genetic map for molecular markers and economically important traits in faba bean (Vicia faba L.)

    PubMed Central

    2013-01-01

    Background Faba bean (Vicia faba L.) is among the earliest domesticated crops from the Near East. Today this legume is a key protein feed and food worldwide and continues to serve an important role in culinary traditions throughout Middle East, Mediterranean region, China and Ethiopia. Adapted to a wide range of soil types, the main faba bean breeding objectives are to improve yield, resistance to biotic and abiotic stresses, seed quality and other agronomic traits. Genomic approaches aimed at enhancing faba bean breeding programs require high-quality genetic linkage maps to facilitate quantitative trait locus analysis and gene tagging for use in a marker-assisted selection. The objective of this study was to construct a reference consensus map in faba bean by joining the information from the most relevant maps reported so far in this crop. Results A combination of two approaches, increasing the number of anchor loci in diverse mapping populations and joining the corresponding genetic maps, was used to develop a reference consensus map in faba bean. The map was constructed from three main recombinant inbreed populations derived from four parental lines, incorporates 729 markers and is based on 69 common loci. It spans 4,602 cM with a range from 323 to 1041 loci in six main linkage groups or chromosomes, and an average marker density of one locus every 6 cM. Locus order is generally well maintained between the consensus map and the individual maps. Conclusion We have constructed a reliable and fairly dense consensus genetic linkage map that will serve as a basis for genomic approaches in faba bean research and breeding. The core map contains a larger number of markers than any previous individual map, covers existing gaps and achieves a wider coverage of the large faba bean genome as a whole. This tool can be used as a reference resource for studies in different genetic backgrounds, and provides a framework for transferring genetic information when using different

  2. TEM Study of Manganese Biosorption by Cyanobacterium Synechocystis 6803

    SciTech Connect

    Dohnalkova, Alice; Bilskis, Christina L.; Kennedy, David W.

    2006-09-01

    The capture of solar energy and its conversion into chemical energy in photosynthetic organisms involves a series of charge reactions across photosynthetic membranes. Oxygen is generated by a proton-electron coupling in photosystem II (PSII) during a water oxidation process where hydrogen is extracted from water terminally bound to a Mn4Ca1Clx inorganic cluster [1]. Manganese is, therefore, an essential catalytic element for photosynthetic growth in cyanobacteria and plants. Since bioavailability of this micronutrient largely depends on the Mn concentration in natural environments, cells have to manage its uptake in order to endure Mn fluctuations. Previous studies have shown that metal biosorption in cyanobacteria can occur by passive adsorption to their outer membrane (pool A), and by metabolically mediated internal uptake [2]. The fresh water cyanobacterium Synechocystis 6803 has been widely used as a model organism for studying photosynthetic processes. This Gram-negative organism has an intricate architecture of internal thylakoid membranes where photosynthetic electron transfer takes place. Here we report on the spatial distribution of Mn biosorbed by cells in both external pool A and intracellular pool B, as observed and analyzed by methods of TEM. The Synechocystis 6803 cells were cultured in BG11 medium at 30 C with continuous irradiance and constant air bubbling. To determine the influence of solid or liquid Mn substrate and its oxidation state on the cell biosorption ability, cells were exposed to two Mn substrates: 1mM solution of MnCl2, and 0.5mM suspension of nanocrystalline MnO2. Cells were incubated with the respective Mn solutions for 48 hours, harvested, and processed using a modified protocol for plastic embedding of bacterial samples containing minerals that was developed in our laboratory [3]. In order to preserve the fragile redox conditions within the cells, all the common heavy metal-based fixatives and stains were omitted, resulting in

  3. Accumulation patterns of lipophilic organic contaminants in surface sediments and in economic important mussel and fish species from Jakarta Bay, Indonesia.

    PubMed

    Dwiyitno; Dsikowitzky, Larissa; Nordhaus, Inga; Andarwulan, Nuri; Irianto, Hari Eko; Lioe, Hanifah Nuryani; Ariyani, Farida; Kleinertz, Sonja; Schwarzbauer, Jan

    2016-09-30

    Non-target screening analyses were conducted in order to identify a wide range of organic contaminants in sediment and animal tissue samples from Jakarta Bay. High concentrations of di-iso-propylnaphthalenes (DIPNs), linear alkylbenzenes (LABs) and polycyclic aromatic hydrocarbons (PAHs) were detected in all samples, whereas phenylmethoxynaphthalene (PMN), DDT and DDT metabolites (DDX) were detected at lower concentrations. In order to evaluate the uptake and accumulation by economic important mussel (Perna viridis) and fish species, contaminant patterns of DIPNs, LABs and PAHs in different compartments were compared. Different patterns of these contaminant groups were found in sediment and animal tissue samples, suggesting compound-specific accumulation and metabolism processes. Significantly higher concentrations of these three contaminant groups in mussel tissue as compared to fish tissue from Jakarta Bay were found. Because P. viridis is an important aquaculture species in Asia, this result is relevant for food safety.

  4. Trichodesmium, a globally significant marine cyanobacterium

    SciTech Connect

    Capone, D.G.; Zehr, J.P.; Paerl, H.W.

    1997-05-23

    Planktonic marine cyanobacteria of the genus Trichodesmium occur throughout the oligotrophic tropical and subtropical oceans. Their unusual adaptations, from the molecular to the macroscopic level, contribute to their ecological success and biogeochemical importance. Trichodesmium fixes nitrogen gas (N{sub 2}) under fully aerobic conditions while photosynthetically evolving oxygen. Its temporal pattern of N{sub 2} fixation results from an enclogenous daily cycle that confines N{sub 2} fixation to daylight hours. Trichodesmium colonies provide a unique pelagic habitat that supports a complex assemblage of consortial organisms. These colonies often represent a large fraction of the plant biomass in tropical, oligotrophic waters and contribute substantially to primary production. N{sub 2} fixation by Trichodesmium is likely a major input to the marine and global nitrogen cycle.

  5. Tilapia: profile and economic importance

    USDA-ARS?s Scientific Manuscript database

    Nile tilapia’s various attributes and an increasing global demand for this fish make it one of the most cultured species, with a global production estimated at nearly 2.5 million tonnes in 2010, and an estimated value of approximately $5 billion. Increased demand in the U.S. market for tilapia produ...

  6. Cyanobacterium sp. host cell and vector for production of chemical compounds in Cyanobacterial cultures

    SciTech Connect

    Piven, Irina; Friedrich, Alexandra; Duhring, Ulf; Uliczka, Frank; Baier, Kerstin; Inaba, Masami; Shi, Tuo; Wang, Kui; Enke, Heike; Kramer, Dan

    2016-04-19

    A cyanobacterial host cell, Cyanobacterium sp., that harbors at least one recombinant gene for the production of a chemical compounds is provided, as well as vectors derived from an endogenous plasmid isolated from the cell.

  7. Mössbauer study of cobalt and iron in the cyanobacterium (blue green alga)

    NASA Astrophysics Data System (ADS)

    Ambe, Shizuko

    1990-07-01

    Mössbauer emission and absorption studies have been performed on cobalt and iron in the cyanobacterium (blue-green alga). The Mössbauer spectrum of the cyanobacterium cultivated with57Co is decomposed into two doublets. The parameters of the major doublet are in good agreement with those of cyanocobalamin (vitamin B12) labeled with57Co. The other minor doublet has parameters close to those of Fe(II) coordinated with six nitrogen atoms. These suggest that cobalt is used for the biosynthesis of vitamin B12 or its analogs in the cyanobacterium. The spectra of the cyanobacterium grown with57Fe show that iron is in the high-spin trivalent state and possibly in the form of ferritin, iron storage protein.

  8. Cyanobacterium sp. host cell and vector for production of chemical compounds in cyanobacterial cultures

    DOEpatents

    Piven, Irina; Friedrich, Alexandra; Duhring, Ulf; Uliczka, Frank; Baier, Kerstin; Inaba, Masami; Shi, Tuo; Wang, Kui; Enke, Heike; Kramer, Dan

    2014-09-30

    A cyanobacterial host cell, Cyanobacterium sp., that harbors at least one recombinant gene for the production of a chemical compounds is provided, as well as vectors derived from an endogenous plasmid isolated from the cell.

  9. Alkane production by the marine cyanobacterium Synechococcus sp. NKBG15041c possessing the α-olefin biosynthesis pathway.

    PubMed

    Yoshino, Tomoko; Liang, Yue; Arai, Daichi; Maeda, Yoshiaki; Honda, Toru; Muto, Masaki; Kakunaka, Natsumi; Tanaka, Tsuyoshi

    2015-02-01

    The production of alkanes in a marine cyanobacterium possessing the α-olefin biosynthesis pathway was achieved by introducing an exogenous alkane biosynthesis pathway. Cyanobacterial hydrocarbons are synthesized via two separate pathways: the acyl-acyl carrier protein (ACP) reductase/aldehyde-deformylating oxygenase (AAR/ADO) pathway for the alkane biosynthesis and the α-olefin synthase (OLS) pathway for the α-olefin biosynthesis. Coexistence of these pathways has not yet been reported. In this study, the marine cyanobacterium Synechococcus sp. NKBG15041c was shown to produce α-olefins similar to those of Synechococcus sp. PCC7002 via the α-olefin biosynthesis pathway. The production of heptadecane in Synechococcus sp. NKBG15041c was achieved by expressing the AAR/ADO pathway genes from Synechococcus elongatus PCC 7942. The production yields of heptadecane in Synechococcus sp. NKBG15041c varied with the expression level of the aar and ado genes. The maximal yield of heptadecane was 4.2 ± 1.2 μg/g of dried cell weight in the transformant carrying a homologous promoter. Our results also suggested that the effective activation of ADO may be more important for the enhancement of alkane production by cyanobacteria.

  10. An economic approach to assessing import policies designed to prevent the arrival of invasive species: the case of Puccinia psidii in Hawai'i

    USGS Publications Warehouse

    Burnett, Kimberly; D'Evelyn, Sean; Loope, Lloyd; Wada, Christopher A.

    2012-01-01

    Since its first documented introduction to Hawai‘i in 2005, the rust fungus Puccinia psidii has already severely damaged Syzygium jambos (Indian rose apple) trees and the federally endangered Eugenia koolauensis (nioi). Fortunately, the particular strain has yet to cause serious damage to Metrosideros polymorpha (‘ōhi‘a), which comprises roughly 80% of the state's native forests and covers 400,000 ha. Although the rust has affected less than 5% of Hawaii's ‘ōhi‘a trees thus far, the introduction of more virulent strains and the genetic evolution of the current strain are still possible. Since the primary pathway of introduction is Myrtaceae plant material imported from outside the state, potential damage to ‘ōhi‘a can be minimized by regulating those high-risk imports. We discuss the economic impact on the state's florist, nursery, landscaping, and forest plantation industries of a proposed rule that would ban the import of non-seed Myrtaceae plant material and require a 1-year quarantine of seeds. Our analysis suggests that the benefits to the forest plantation industry of a complete ban on non-seed material would likely outweigh the costs to other affected sectors, even without considering the reduction in risk to ‘ōhi‘a. Incorporating the value of ‘ōhi‘a protection would further increase the benefit–cost ratio in favor of an import ban.

  11. The economic importance of acaricides in the control of phytophagous mites and an update on recent acaricide mode of action research.

    PubMed

    Van Leeuwen, Thomas; Tirry, Luc; Yamamoto, Atsushi; Nauen, Ralf; Dermauw, Wannes

    2015-06-01

    Acaricides are one of the cornerstones of an efficient control program for phytophagous mites. An analysis of the global acaricide market reveals that spider mites such as Tetranychus urticae, Panonychus citri and Panonychus ulmi are by far the most economically important species, representing more than 80% of the market. Other relevant mite groups are false spider mites (mainly Brevipalpus), rust and gall mites and tarsonemid mites. Acaricides are most frequently used in vegetables and fruits (74% of the market), including grape vines and citrus. However, their use is increasing in major crops where spider mites are becoming more important, such as soybean, cotton and corn. As revealed by a detailed case study of the Japanese market, major shifts in acaricide use are partially driven by resistance development and the commercial availability of compounds with novel mode of action. The importance of the latter cannot be underestimated, although some compounds are successfully used for more than 30 years. A review of recent developments in mode of action research is presented, as such knowledge is important for devising resistance management programs. This includes spirocyclic keto-enols as inhibitors of acetyl-CoA carboxylase, the carbazate bifenazate as a mitochondrial complex III inhibitor, a novel class of complex II inhibitors, and the mite growth inhibitors hexythiazox, clofentezine and etoxazole that interact with chitin synthase I. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Characterization of corrinoid compounds from edible cyanobacterium Nostochopsis sp.

    PubMed

    Hashimoto, Eri; Yabuta, Yukinori; Takenaka, Shigeo; Yamaguchi, Yuji; Takenaka, Hiroyuki; Watanabe, Fumio

    2012-01-01

    Vitamin B₁₂ content of an edible cyanobacterium, Nostochopsis sp. was determined to be 140.6±16.2 μg/100 g dry weight by a microbiological method. To evaluate whether the Nostochopsis cells contain vitamin B₁₂ or inactive corrinoid compounds, corrinoid compounds were purified from the cells and then identified as pseudovitamin B₁₂ (97.4±11.8 μg/100 g dry weight) and vitamin B₁₂ (43.2±6.0 μg/100 g dry weight) on the basis of silica gel 60 TLC bioautograms and LC/ESI-MS/MS chromatograms. Vitamin B₁₂ content was significantly increased in the Nostochopsis cells (254.8±17.6 μg/100 g dry weight) grown in the vitamin B₁₂-supplemented medium.

  13. Genomes of diverse isolates of the marine cyanobacterium Prochlorococcus

    PubMed Central

    Biller, Steven J.; Berube, Paul M.; Berta-Thompson, Jessie W.; Kelly, Libusha; Roggensack, Sara E.; Awad, Lana; Roache-Johnson, Kathryn H.; Ding, Huiming; Giovannoni, Stephen J.; Rocap, Gabrielle; Moore, Lisa R.; Chisholm, Sallie W.

    2014-01-01

    The marine cyanobacterium Prochlorococcus is the numerically dominant photosynthetic organism in the oligotrophic oceans, and a model system in marine microbial ecology. Here we report 27 new whole genome sequences (2 complete and closed; 25 of draft quality) of cultured isolates, representing five major phylogenetic clades of Prochlorococcus. The sequenced strains were isolated from diverse regions of the oceans, facilitating studies of the drivers of microbial diversity—both in the lab and in the field. To improve the utility of these genomes for comparative genomics, we also define pre-computed clusters of orthologous groups of proteins (COGs), indicating how genes are distributed among these and other publicly available Prochlorococcus genomes. These data represent a significant expansion of Prochlorococcus reference genomes that are useful for numerous applications in microbial ecology, evolution and oceanography. PMID:25977791

  14. A New Lyngbyatoxin from the Hawaiian Cyanobacterium Moorea producens

    PubMed Central

    Jiang, Weina; Zhou, Wei; Uchida, Hajime; Kikumori, Masayuki; Irie, Kazuhiro; Watanabe, Ryuichi; Suzuki, Toshiyuki; Sakamoto, Bryan; Kamio, Michiya; Nagai, Hiroshi

    2014-01-01

    Lyngbyatoxin A from the marine cyanobacterium Moorea producens (formerly Lyngbya majuscula) is known as the causative agent of “swimmer’s itch” with its highly inflammatory effect. A new toxic compound was isolated along with lyngbyatoxin A from an ethyl acetate extract of M. producens collected from Hawaii. Analyses of HR-ESI-MS and NMR spectroscopies revealed the isolated compound had the same planar structure with that of lyngbyatoxin A. The results of optical rotation and CD spectra indicated that the compound was a new lyngbyatoxin A derivative, 12-epi-lyngbyatoxin A (1). While 12-epi-lyngbyatoxin A showed comparable toxicities with lyngbyatoxin A in cytotoxicity and crustacean lethality tests, it showed more than 100 times lower affinity for protein kinase Cδ (PKCδ) using the PKCδ-C1B peptide when compared to lyngbyatoxin A. PMID:24824022

  15. Photoinhibition and reactivation of photosynthesis in the cyanobacterium Anacystis nidulans

    SciTech Connect

    Samuelsson, G.; Loenneborg, A.; Rosenqvist, E.; Gustafsson, P.; Oequist, G.

    1985-12-01

    The susceptibility of photosynthesis to photoinhibition and its recovery were studied on cultures of the cyanobacterium Anacystis nidulans. Oxygen evolution and low temperature fluorescence kinetics were measured. Upon exposure to high light A. nidulans showed a rapid decrease in oxygen evolution followed by a quasi steady state rate of photosynthesis. This quasi steady state rate decreased with increasing photon flux density of the photoinhibitory light. Reactivation of photosynthesis in dim light after the photoinhibitory treatment was rapid: 85 to 95% recovery occurred within 2 hours. In the presence of the translation inhibitor, streptomycin (250 micrograms per milliliter), no reactivation occurred. We also found that the damage increased dramatically if the high light treatment was done with streptomycin added. A transcription inhibitor, rifampicin, did not inhibit the reactivation process. Based on these data we conclude that the photoinhibitory damage observed is the net result of a balance between the photoinhibitory process and the operation of the repairing mechanism(s).

  16. Putative recombination events and evolutionary history of five economically important viruses of fruit trees based on coat protein-encoding gene sequence analysis.

    PubMed

    Boulila, Moncef

    2010-06-01

    To enhance the knowledge of recombination as an evolutionary process, 267 accessions retrieved from GenBank were investigated, all belonging to five economically important viruses infecting fruit crops (Plum pox, Apple chlorotic leaf spot, Apple mosaic, Prune dwarf, and Prunus necrotic ringspot viruses). Putative recombinational events were detected in the coat protein (CP)-encoding gene using RECCO and RDP version 3.31beta algorithms. Based on RECCO results, all five viruses were shown to contain potential recombination signals in the CP gene. Reconstructed trees with modified topologies were proposed. Furthermore, RECCO performed better than the RDP package in detecting recombination events and exhibiting their evolution rate along the sequences of the five viruses. RDP, however, provided the possible major and minor parents of the recombinants. Thus, the two methods should be considered complementary.

  17. Construction and characterization of two bacterial artificial chromosome libraries of pea (Pisum sativum L.) for the isolation of economically important genes.

    PubMed

    Coyne, C J; McClendon, M T; Walling, J G; Timmerman-Vaughan, G M; Murray, S; Meksem, K; Lightfoot, D A; Shultz, J L; Keller, K E; Martin, R R; Inglis, D A; Rajesh, P N; McPhee, K E; Weeden, N F; Grusak, M A; Li, C-M; Storlie, E W

    2007-09-01

    Pea (Pisum sativum L.) has a genome of about 4 Gb that appears to share conserved synteny with model legumes having genomes of 0.2-0.4 Gb despite extensive intergenic expansion. Pea plant inventory (PI) accession 269818 has been used to introgress genetic diversity into the cultivated germplasm pool. The aim here was to develop pea bacterial artificial chromosome (BAC) libraries that would enable the isolation of genes involved in plant disease resistance or control of economically important traits. The BAC libraries encompassed about 3.2 haploid genome equivalents consisting of partially HindIII-digested DNA fragments with a mean size of 105 kb that were inserted in 1 of 2 vectors. The low-copy oriT-based T-DNA vector (pCLD04541) library contained 55 680 clones. The single-copy oriS-based vector (pIndigoBAC-5) library contained 65 280 clones. Colony hybridization of a universal chloroplast probe indicated that about 1% of clones in the libraries were of chloroplast origin. The presence of about 0.1% empty vectors was inferred by white/blue colony plate counts. The usefulness of the libraries was tested by 2 replicated methods. First, high-density filters were probed with low copy number sequences. Second, BAC plate-pool DNA was used successfully to PCR amplify 7 of 9 published pea resistance gene analogs (RGAs) and several other low copy number pea sequences. Individual BAC clones encoding specific sequences were identified. Therefore, the HindIII BAC libraries of pea, based on germplasm accession PI 269818, will be useful for the isolation of genes underlying disease resistance and other economically important traits.

  18. Competition and facilitation between the marine nitrogen-fixing cyanobacterium Cyanothece and its associated bacterial community.

    PubMed

    Brauer, Verena S; Stomp, Maayke; Bouvier, Thierry; Fouilland, Eric; Leboulanger, Christophe; Confurius-Guns, Veronique; Weissing, Franz J; Stal, LucasJ; Huisman, Jef

    2014-01-01

    N2-fixing cyanobacteria represent a major source of new nitrogen and carbon for marine microbial communities, but little is known about their ecological interactions with associated microbiota. In this study we investigated the interactions between the unicellular N2-fixing cyanobacterium Cyanothece sp. Miami BG043511 and its associated free-living chemotrophic bacteria at different concentrations of nitrate and dissolved organic carbon and different temperatures. High temperature strongly stimulated the growth of Cyanothece, but had less effect on the growth and community composition of the chemotrophic bacteria. Conversely, nitrate and carbon addition did not significantly increase the abundance of Cyanothece, but strongly affected the abundance and species composition of the associated chemotrophic bacteria. In nitrate-free medium the associated bacterial community was co-dominated by the putative diazotroph Mesorhizobium and the putative aerobic anoxygenic phototroph Erythrobacter and after addition of organic carbon also by the Flavobacterium Muricauda. Addition of nitrate shifted the composition toward co-dominance by Erythrobacter and the Gammaproteobacterium Marinobacter. Our results indicate that Cyanothece modified the species composition of its associated bacteria through a combination of competition and facilitation. Furthermore, within the bacterial community, niche differentiation appeared to play an important role, contributing to the coexistence of a variety of different functional groups. An important implication of these findings is that changes in nitrogen and carbon availability due to, e.g., eutrophication and climate change are likely to have a major impact on the species composition of the bacterial community associated with N2-fixing cyanobacteria.

  19. Phosphoproteome of the cyanobacterium Synechocystis sp. PCC 6803 and its dynamics during nitrogen starvation.

    PubMed

    Spät, Philipp; Maček, Boris; Forchhammer, Karl

    2015-01-01

    Cyanobacteria have shaped the earth's biosphere as the first oxygenic photoautotrophs and still play an important role in many ecosystems. The ability to adapt to changing environmental conditions is an essential characteristic in order to ensure survival. To this end, numerous studies have shown that bacteria use protein post-translational modifications such as Ser/Thr/Tyr phosphorylation in cell signaling, adaptation, and regulation. Nevertheless, our knowledge of cyanobacterial phosphoproteomes and their dynamic response to environmental stimuli is relatively limited. In this study, we applied gel-free methods and high accuracy mass spectrometry toward the detection of Ser/Thr/Tyr phosphorylation events in the model cyanobacterium Synechocystis sp. PCC 6803. We could identify over 300 phosphorylation events in cultures grown on nitrate as exclusive nitrogen source. Chemical dimethylation labeling was applied to investigate proteome and phosphoproteome dynamics during nitrogen starvation. Our dataset describes the most comprehensive (phospho)proteome of Synechocystis to date, identifying 2382 proteins and 183 phosphorylation events and quantifying 2111 proteins and 148 phosphorylation events during nitrogen starvation. Global protein phosphorylation levels were increased in response to nitrogen depletion after 24 h. Among the proteins with increased phosphorylation, the PII signaling protein showed the highest fold-change, serving as positive control. Other proteins with increased phosphorylation levels comprised functions in photosynthesis and in carbon and nitrogen metabolism. This study reveals dynamics of Synechocystis phosphoproteome in response to environmental stimuli and suggests an important role of protein Ser/Thr/Tyr phosphorylation in fundamental mechanisms of homeostatic control in cyanobacteria.

  20. Identifying obstacles and ranking common biological control research priorities for Europe to manage most economically important pests in arable, vegetable and perennial crops.

    PubMed

    Lamichhane, Jay Ram; Bischoff-Schaefer, Monika; Bluemel, Sylvia; Dachbrodt-Saaydeh, Silke; Dreux, Laure; Jansen, Jean-Pierre; Kiss, Jozsef; Köhl, Jürgen; Kudsk, Per; Malausa, Thibaut; Messéan, Antoine; Nicot, Philippe C; Ricci, Pierre; Thibierge, Jérôme; Villeneuve, François

    2017-01-01

    EU agriculture is currently in transition from conventional crop protection to integrated pest management (IPM). Because biocontrol is a key component of IPM, many European countries recently have intensified their national efforts on biocontrol research and innovation (R&I), although such initiatives are often fragmented. The operational outputs of national efforts would benefit from closer collaboration among stakeholders via transnationally coordinated approaches, as most economically important pests are similar across Europe. This paper proposes a common European framework on biocontrol R&I. It identifies generic R&I bottlenecks and needs as well as priorities for three crop types (arable, vegetable and perennial crops). The existing gap between the market offers of biocontrol solutions and the demand of growers, the lengthy and expensive registration process for biocontrol solutions and their varying effectiveness due to variable climatic conditions and site-specific factors across Europe are key obstacles hindering the development and adoption of biocontrol solutions in Europe. Considering arable, vegetable and perennial crops, a dozen common target pests are identified for each type of crop and ranked by order of importance at European level. Such a ranked list indicates numerous topics on which future joint transnational efforts would be justified. © 2016 Society of Chemical Industry.

  1. Genetic variability associated with photosynthetic pigment concentration, and photochemical and nonphotochemical quenching, in strains of the cyanobacterium Microcystis aeruginosa.

    PubMed

    Bañares-España, Elena; López-Rodas, Victoria; Costas, Eduardo; Salgado, Concepción; Flores-Moya, Antonio

    2007-06-01

    Although populations of cyanobacteria are usually considered to be clonal, their capacity to survive environmental changes suggests intrapopulation genetic variation. We therefore estimated the genetic variability on the basis of two processes important for any photoautotroph - photochemical and nonphotochemical quenching - as well as photosynthetic pigment concentrations. For this purpose, two parameters related to photochemical and nonphotochemical quenching were measured using specific experimental and statistical procedures, in 25 strains of the cyanobacterium Microcystis aeruginosa, along with their contents of chlorophyll a, total carotenoids and phycocyanin. The experimental procedure allowed discrimination between genetic and nongenetic (or residual) variability among strains. The high genetic variability found in photosynthetic pigments and both photosynthetic parameters denotes large differences even among strains isolated from the same community. The high genetic diversity within a population could be important for the evolutionary success of cyanobacteria.

  2. ABC Transporter Required for Intercellular Transfer of Developmental Signals in a Heterocystous Cyanobacterium

    PubMed Central

    Videau, Patrick; Rivers, Orion S.; Higa, Kelly C.

    2015-01-01

    ABSTRACT In the filamentous cyanobacterium Anabaena, patS and hetN encode peptide-derived signals with many of the properties of morphogens. These signals regulate the formation of a periodic pattern of heterocysts by lateral inhibition of differentiation. Here we show that intercellular transfer of the patS- and hetN-dependent developmental signals from heterocysts to vegetative cells requires HetC, a predicted ATP-binding cassette transporter (ABC transporter). Relative to the wild type, in a hetC mutant differentiation resulted in a reduced number of heterocysts that were incapable of nitrogen fixation, but deletion of patS or hetN restored heterocyst number and function in a hetC background. These epistasis results suggest that HetC is necessary for conferring self-immunity to the inhibitors on differentiating cells. Nine hours after induction of differentiation, HetC was required for neither induction of transcription of patS nor intercellular transfer of the patS-encoded signal to neighboring cells. Conversely, in strains lacking HetC, the patS- and hetN-encoded signals were not transferred from heterocyst cells to adjacent vegetative cells. The results support a model in which the patS-dependent signal is initially transferred between vegetative cells in a HetC-independent fashion, but some time before morphological differentiation of heterocysts is complete, transfer of both signals transitions to a HetC-dependent process. IMPORTANCE How chemical cues that regulate pattern formation in multicellular organisms move from one cell to another is a central question in developmental biology. In this study, we show that an ABC transporter, HetC, is necessary for transport of two developmental signals between different types of cells in a filamentous cyanobacterium. ABC transporters are found in organisms as diverse as bacteria and humans and, as the name implies, are often involved in the transport of molecules across a cellular membrane. The activity of HetC was

  3. Comparative Amperometric Study of Uptake Hydrogenase and Hydrogen Photoproduction Activities between Heterocystous Cyanobacterium Anabaena cylindrica B629 and Nonheterocystous Cyanobacterium Oscillatoria sp. Strain Miami BG7

    PubMed Central

    Kumazawa, S.; Mitsui, A.

    1985-01-01

    Heterocystous filamentous cyanobacterium Anabaena cylindrica B629 and nonheterocystous filamentous cyanobacterium Oscillatoria sp. strain Miami BG7 were cultured in media with N2 as the sole nitrogen source; and activities of oxygen-dependent hydrogen uptake, photohydrogen production, photooxygen evolution, and respiration were compared amperometrically under the same or similar experimental conditions for both strains. Distinct differences in these activities were observed in both strains. The rates of hydrogen photoproduction and hydrogen accumulation were significantly higher in Oscillatoria sp. strain BG7 than in A. cylindrica B629 at every light intensity tested. The major reason for the difference was attributable to the fact that the heterocystous cyanobacterium had a high rate of oxygen-dependent hydrogen consumption activity and the nonheterocystous cyanobacterium did not. The activity of oxygen photoevolution and respiration also contributed to the difference. Oscillatoria sp. strain BG7 had lower O2 evolution and higher respiration than did A. cylindrica B629. Thus, the effect of O2 on hydrogen photoproduction was minimized in Oscillatoria sp. strain BG7. PMID:16346850

  4. Draft Genome Sequence of the Axenic Strain Phormidesmispriestleyi ULC007, a Cyanobacterium Isolated from Lake Bruehwiler (Larsemann Hills, Antarctica).

    PubMed

    Lara, Yannick; Durieu, Benoit; Cornet, Luc; Verlaine, Olivier; Rippka, Rosmarie; Pessi, Igor S; Misztak, Agnieszka; Joris, Bernard; Javaux, Emmanuelle J; Baurain, Denis; Wilmotte, Annick

    2017-02-16

    Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacterium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein-encoding genes, of which 22.2% have no clear homologues in known genomes. To date, this draft genome is the first one ever determined for an axenic cyanobacterium from Antarctica.

  5. CRISPR/Cas9 mediated targeted mutagenesis of the fast growing cyanobacterium Synechococcus elongatus UTEX 2973

    DOE PAGES

    Wendt, Kristen E.; Ungerer, Justin; Cobb, Ryan E.; ...

    2016-06-23

    As autotrophic prokaryotes, cyanobacteria are ideal chassis organisms for sustainable production of various useful compounds. The newly characterized cyanobacterium Synechococcus elongatus UTEX 2973 is a promising candidate for serving as a microbial cell factory because of its unusually rapid growth rate. Here, we seek to develop a genetic toolkit that enables extensive genomic engineering of Synechococcus 2973 by implementing a CRISPR/Cas9 editing system. We targeted the nblA gene because of its important role in biological response to nitrogen deprivation conditions. First, we determined that the Streptococcus pyogenes Cas9 enzyme is toxic in cyanobacteria, and conjugational transfer of stable, replicating constructsmore » containing the cas9 gene resulted in lethality. However, after switching to a vector that permitted transient expression of the cas9 gene, we achieved markerless editing in 100 % of cyanobacterial exconjugants after the first patch. Moreover, we could readily cure the organisms of antibiotic resistance, resulting in a markerless deletion strain. In conclusion, high expression levels of the Cas9 protein in Synechococcus 2973 appear to be toxic and result in cell death. However, introduction of a CRISPR/Cas9 genome editing system on a plasmid backbone that leads to transient cas9 expression allowed for efficient markerless genome editing in a wild type genetic background.« less

  6. Response of photosynthetic systems to salinity stress in the desert cyanobacterium Scytonema javanicum

    NASA Astrophysics Data System (ADS)

    Hu, Jinlu; Jin, Liang; Wang, Xiaojuan; Cai, Wenkai; Liu, Yongding; Wang, Gaohong

    2014-01-01

    The present study investigated the physiological and biochemical characteristics of Scytonema javanicum, a pioneer species isolated from desert biological crusts, under salinity stress. Pigment analysis showed that salinity decreased chlorophyll a and phycocyanin content, while low salinity increased carotenoid concentration and high salinity decreased carotenoid concentration. Salinity also inhibited CO2 assimilation rate and photosynthetic oxygen evolution in this cyanobacterium. Chlorophyll a fluorescence transient parameters (φPo, φEo, ψO, RC/ABS, RC/CS, PIABS, and PICS) were decreased under salt stress, while dVo/dto(Mo), Vj and φDo were increased. The decrease of ETRmax and Yield and the change of chlorophyll a fluorescence transients showed that salt stress had an important influence on photosynthesis. These results indicated that the effects of salinity stress on photosynthesis in S. javanicum may depend on the inhibition of electron transport and the inactivation of the reaction centers, but this inhibition may occur in the electron transport pathway at the PSII donor and acceptor sites.

  7. CyanOmics: an integrated database of omics for the model cyanobacterium Synechococcus sp. PCC 7002

    PubMed Central

    Yang, Yaohua; Feng, Jie; Li, Tao; Ge, Feng; Zhao, Jindong

    2015-01-01

    Cyanobacteria are an important group of organisms that carry out oxygenic photosynthesis and play vital roles in both the carbon and nitrogen cycles of the Earth. The annotated genome of Synechococcus sp. PCC 7002, as an ideal model cyanobacterium, is available. A series of transcriptomic and proteomic studies of Synechococcus sp. PCC 7002 cells grown under different conditions have been reported. However, no database of such integrated omics studies has been constructed. Here we present CyanOmics, a database based on the results of Synechococcus sp. PCC 7002 omics studies. CyanOmics comprises one genomic dataset, 29 transcriptomic datasets and one proteomic dataset and should prove useful for systematic and comprehensive analysis of all those data. Powerful browsing and searching tools are integrated to help users directly access information of interest with enhanced visualization of the analytical results. Furthermore, Blast is included for sequence-based similarity searching and Cluster 3.0, as well as the R hclust function is provided for cluster analyses, to increase CyanOmics’s usefulness. To the best of our knowledge, it is the first integrated omics analysis database for cyanobacteria. This database should further understanding of the transcriptional patterns, and proteomic profiling of Synechococcus sp. PCC 7002 and other cyanobacteria. Additionally, the entire database framework is applicable to any sequenced prokaryotic genome and could be applied to other integrated omics analysis projects. Database URL: http://lag.ihb.ac.cn/cyanomics PMID:25632108

  8. Genomics of variation in nitrogen fixation activity in a population of the thermophilic cyanobacterium Mastigocladus laminosus.

    PubMed

    Hutchins, Patrick R; Miller, Scott R

    2017-01-01

    Variation in phenotypic traits that contribute to fitness influences a population's evolutionary response and its impact on ecosystem function following environmental change, yet its amount and nature are rarely known. Here, we investigated variation in nitrogen (N) fixation activity and its genetic basis for a random sample of laboratory strains of the cyanobacterium Mastigocladus laminosus from a N-limited, geothermally influenced stream in Yellowstone National Park. In a linear mixed-effects model, temperature and genetic differences among strains were the most important factors explaining variation in activity. Genome-wide analyses of genetic divergence between groups of strains that varied in N fixation activity revealed that few loci were strongly associated with these phenotypic differences. Notably, a single nonsynonymous polymorphism in the sulfate assimilation gene apsK explained >25% of the variation in activity at high temperature. We further identified a role for allelic variation of multiple terminal cytochrome oxidases for different aspects of N fixation. In addition, genomes of strains that fixed the most N overall contained a nonsense mutation in a histidine kinase gene that is expected to disrupt normal protein function and may result in transcriptional rewiring. This study illustrates how taking complementary approaches to link phenotype and genotype can inform our understanding of microbial population diversity.

  9. Optimization of photobioreactor growth conditions for a cyanobacterium expressing mosquitocidal Bacillus thuringiensis Cry proteins.

    PubMed

    Ketseoglou, Irene; Bouwer, Gustav

    2013-08-10

    An Anabaena strain (PCC 7120#11) that was genetically engineered to express Bacillus thuringiensis subsp. israelensis cry genes has shown good larvicidal activity against Anopheles arabiensis, a major vector of malaria in Africa. Response surface methodology was used to evaluate the relationship between key growth factors and the volumetric productivity of PCC 7120#11 in an indoor, flat-plate photobioreactor. The interaction of input CO₂ concentration and airflow rate had a statistically significant effect on the volumetric productivity of PCC 7120#11, as did the interaction of airflow rate and photosynthetic photon flux density. Model-based numerical optimization indicated that the optimal factor level combination for maximizing PCC 7120#11 volumetric productivity was a photosynthetic photon flux density of 154 μmol m⁻² s⁻¹ and air enriched with 3.18% (v/v) CO₂ supplied at a flow rate of 1.02 vessel volumes per minute. At the levels evaluated in the study, none of the growth factors had a significant effect on the median lethal concentration of PCC 7120#11 against An. arabiensis larvae. This finding is important because loss of mosquitocidal activity under growth conditions that maximize volumetric productivity would impact on the feasibility of using PCC 7120#11 in malaria vector control programs. The study showed the usefulness of response surface methodology for determination of the optimal growth conditions for a cyanobacterium that is genetically engineered to have larvicidal activity against malaria vectors.

  10. Enhanced ferrihydrite dissolution by a unicellular, planktonic cyanobacterium: a biological contribution to particulate iron bioavailability.

    PubMed

    Kranzler, Chana; Kessler, Nivi; Keren, Nir; Shaked, Yeala

    2016-12-01

    Iron (Fe) bioavailability, as determined by its sources, sinks, solubility and speciation, places severe environmental constraints on microorganisms in aquatic environments. Cyanobacteria are a widespread group of aquatic, photosynthetic microorganisms with especially high iron requirements. While iron exists predominantly in particulate form, little is known about its bioavailability to cyanobacteria. Some cyanobacteria secrete iron solubilizing ligands called siderophores, yet many environmentally relevant strains do not have this ability. This work explores the bioavailability of amorphous synthetic Fe-oxides (ferrihydrite) to the non-siderophore producing, unicellular cyanobacterium, Synechocystis sp PCC 6803. Iron uptake assays with (55) ferrihydrite established dissolution as a critical prerequisite for iron transport. Dissolution assays with the iron binding ligand, desferrioxamine B, demonstrated that Synechocystis 6803 enhances ferrihydrite dissolution, exerting siderophore-independent biological influence on ferrihydrite bioavailability. Dissolution mechanisms were studied using a range of experimental conditions; both cell-particle physical proximity and cellular electron flow were shown to be important determinants of bio-dissolution by Synechocystis 6803. Finally, the effects of ferrihydrite stability on bio-dissolution rates and cell physiology were measured, integrating biological and chemical aspects of ferrihydrite bioavailability. Collectively, these findings demonstrate that Synechocystis 6803 actively dissolves ferrihydrite, highlighting a significant biological component to mineral phase iron bioavailability in aquatic environments.

  11. Near-UV cyanobacteriochrome signaling system elicits negative phototaxis in the cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Song, Ji-Young; Cho, Hye Sun; Cho, Jung-Il; Jeon, Jong-Seong; Lagarias, J Clark; Park, Youn-Il

    2011-06-28

    Positive phototaxis systems have been well studied in bacteria; however, the photoreceptor(s) and their downstream signaling components that are responsible for negative phototaxis are poorly understood. Negative phototaxis sensory systems are important for cyanobacteria, oxygenic photosynthetic organisms that must contend with reactive oxygen species generated by an abundance of pigment photosensitizers. The unicellular cyanobacterium Synechocystis sp. PCC6803 exhibits type IV pilus-dependent negative phototaxis in response to unidirectional UV-A illumination. Using a reverse genetic approach, together with biochemical, molecular genetic, and RNA expression profiling analyses, we show that the cyanobacteriochrome locus (slr1212/uirS) of Synechocystis and two adjacent response regulator loci (slr1213/uirR and the PatA-type regulator slr1214/lsiR) encode a UV-A-activated signaling system that is required for negative phototaxis. We propose that UirS, which is membrane-associated via its ETR1 domain, functions as a UV-A photosensor directing expression of lsiR via release of bound UirR, which targets the lsiR promoter. Constitutive expression of LsiR induces negative phototaxis under conditions that normally promote positive phototaxis. Also induced by other stresses, LsiR thus integrates light inputs from multiple photosensors to determine the direction of movement.

  12. Near-UV cyanobacteriochrome signaling system elicits negative phototaxis in the cyanobacterium Synechocystis sp. PCC 6803

    PubMed Central

    Song, Ji-Young; Cho, Hye Sun; Cho, Jung-Il; Jeon, Jong-Seong; Lagarias, J. Clark; Park, Youn-Il

    2011-01-01

    Positive phototaxis systems have been well studied in bacteria; however, the photoreceptor(s) and their downstream signaling components that are responsible for negative phototaxis are poorly understood. Negative phototaxis sensory systems are important for cyanobacteria, oxygenic photosynthetic organisms that must contend with reactive oxygen species generated by an abundance of pigment photosensitizers. The unicellular cyanobacterium Synechocystis sp. PCC6803 exhibits type IV pilus-dependent negative phototaxis in response to unidirectional UV-A illumination. Using a reverse genetic approach, together with biochemical, molecular genetic, and RNA expression profiling analyses, we show that the cyanobacteriochrome locus (slr1212/uirS) of Synechocystis and two adjacent response regulator loci (slr1213/uirR and the PatA-type regulator slr1214/lsiR) encode a UV-A–activated signaling system that is required for negative phototaxis. We propose that UirS, which is membrane-associated via its ETR1 domain, functions as a UV-A photosensor directing expression of lsiR via release of bound UirR, which targets the lsiR promoter. Constitutive expression of LsiR induces negative phototaxis under conditions that normally promote positive phototaxis. Also induced by other stresses, LsiR thus integrates light inputs from multiple photosensors to determine the direction of movement. PMID:21670284

  13. Advances in the Function and Regulation of Hydrogenase in the Cyanobacterium Synechocystis PCC6803

    PubMed Central

    Cassier-Chauvat, Corinne; Veaudor, Théo; Chauvat, Franck

    2014-01-01

    In order to use cyanobacteria for the biological production of hydrogen, it is important to thoroughly study the function and the regulation of the hydrogen-production machine in order to better understand its role in the global cell metabolism and identify bottlenecks limiting H2 production. Most of the recent advances in our understanding of the bidirectional [Ni-Fe] hydrogenase (Hox) came from investigations performed in the widely-used model cyanobacterium Synechocystis PCC6803 where Hox is the sole enzyme capable of combining electrons with protons to produce H2 under specific conditions. Recent findings suggested that the Hox enzyme can receive electrons from not only NAD(P)H as usually shown, but also, or even preferentially, from ferredoxin. Furthermore, plasmid-encoded functions and glutathionylation (the formation of a mixed-disulfide between the cysteines residues of a protein and the cysteine residue of glutathione) are proposed as possible new players in the function and regulation of hydrogen production. PMID:25365180

  14. Engineered platform for bioethylene production by a cyanobacterium expressing a chimeric complex of plant enzymes.

    PubMed

    Jindou, Sadanari; Ito, Yuki; Mito, Natsumi; Uematsu, Keiji; Hosoda, Akifumi; Tamura, Hiroto

    2014-07-18

    Ethylene is an industrially important compound, but more sustainable production methods are desirable. Since cellulosomes increase the ability of cellulolytic enzymes by physically linking the relevant enzymes via dockerin-cohesin interactions, in this study, we genetically engineered a chimeric cellulosome-like complex of two ethylene-generating enzymes from tomato using cohesin-dockerins from the bacteria Clostridium thermocellum and Acetivibrio cellulolyticus. This complex was transformed into Escherichia coli to analyze kinetic parameters and enzyme complex formation and into the cyanobacterium Synechococcus elongatus PCC 7942, which was then grown with and without 0.1 mM isopropyl β-D-1-thiogalactopyranoside (IPTG) induction. Only at minimal protein expression levels (without IPTG), the chimeric complex produced 3.7 times more ethylene in vivo than did uncomplexed enzymes. Thus, cyanobacteria can be used to sustainably generate ethylene, and the synthetic enzyme complex greatly enhanced production efficiency. Artificial synthetic enzyme complexes hold great promise for improving the production efficiency of other industrial compounds.

  15. Membrane development in the cyanobacterium, Anacystis nidulans, during recovery from iron starvation

    SciTech Connect

    Pakrasi, H.B.; Goldenberg, A.; Sherman, L.A.

    1985-09-01

    Deprivation of iron from the growth medium results in physiological as well as structural changes in the unicellular cyanobacterium Anacystis nidulans R2. Important among these changes are alterations in the composition and function of the photosynthetic membranes. Room-temperature absorption spectra of iron-starved cyanobacterial cells show a chlorophyll absorption peak at 672 nanometers, 7 nanometers blue-shifted from its normal position at 679 nanometers. Iron-starved cells have decreased amounts of chlorophyll and phycobilins. Their fluorescence spectra (77K) have one prominent chlorophyll emission peak at 684 nanometers as compared to three peaks at 687, 696, and 717 nanometers from normal cells. Chlorophyll-protein analysis of iron-deprived cells indicated the absence of high molecular weight bands. Addition of iron to iron-starved cells induced a restoration process in which new components were initially synthesized and integrated into preexisting membranes; at later times, new membranes were assembled and cell division commenced. Synthesis of chlorophyll and phycocyanins started almost immediately after the addition of iron. The origin of the fluorescence emission at 687 and 696 nanometers is discussed in relation to the specific chlorophyll-protein complexes formed during iron reconstitution. 26 references, 2 figures, 1 table.

  16. A model of cyclic transcriptomic behavior in the cyanobacterium Cyanothece sp. ATCC 51142.

    PubMed

    McDermott, Jason E; Oehmen, Christopher S; McCue, Lee Ann; Hill, Eric; Choi, Daniel M; Stöckel, Jana; Liberton, Michelle; Pakrasi, Himadri B; Sherman, Louis A

    2011-08-01

    Systems biology attempts to reconcile large amounts of disparate data with existing knowledge to provide models of functioning biological systems. The cyanobacterium Cyanothece sp. ATCC 51142 is an excellent candidate for such systems biology studies because: (i) it displays tight functional regulation between photosynthesis and nitrogen fixation; (ii) it has robust cyclic patterns at the genetic, protein and metabolomic levels; and (iii) it has potential applications for bioenergy production and carbon sequestration. We have represented the transcriptomic data from Cyanothece 51142 under diurnal light/dark cycles as a high-level functional abstraction and describe development of a predictive in silico model of diurnal and circadian behavior in terms of regulatory and metabolic processes in this organism. We show that incorporating network topology into the model improves performance in terms of our ability to explain the behavior of the system under new conditions. The model presented robustly describes transcriptomic behavior of Cyanothece 51142 under different cyclic and non-cyclic growth conditions, and represents a significant advance in the understanding of gene regulation in this important organism.

  17. Refolding and enzyme kinetic studies on the ferrochelatase of the cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Storm, Patrik; Tibiletti, Tania; Hall, Michael; Funk, Christiane

    2013-01-01

    Heme is a cofactor for proteins participating in many important cellular processes, including respiration, oxygen metabolism and oxygen binding. The key enzyme in the heme biosynthesis pathway is ferrochelatase (protohaem ferrolyase, EC 4.99.1.1), which catalyzes the insertion of ferrous iron into protoporphyrin IX. In higher plants, the ferrochelatase enzyme is localized not only in mitochondria, but also in chloroplasts. The plastidic type II ferrochelatase contains a C-terminal chlorophyll a/b (CAB) motif, a conserved hydrophobic stretch homologous to the CAB domain of plant light harvesting proteins and light-harvesting like proteins. This type II ferrochelatase, found in all photosynthetic organisms, is presumed to have evolved from the cyanobacterial ferrochelatase. Here we describe a detailed enzymological study on recombinant, refolded and functionally active type II ferrochelatase (FeCh) from the cyanobacterium Synechocystis sp. PCC 6803. A protocol was developed for the functional refolding and purification of the recombinant enzyme from inclusion bodies, without truncation products or soluble aggregates. The refolded FeCh is active in its monomeric form, however, addition of an N-terminal His(6)-tag has significant effects on its enzyme kinetics. Strikingly, removal of the C-terminal CAB-domain led to a greatly increased turnover number, k(cat), compared to the full length protein. While pigments isolated from photosynthetic membranes decrease the activity of FeCh, direct pigment binding to the CAB domain of FeCh was not evident.

  18. Unusual marine unicellular symbiosis with the nitrogen-fixing cyanobacterium UCYN-A.

    PubMed

    Zehr, Jonathan P; Shilova, Irina N; Farnelid, Hanna M; Muñoz-MarínCarmen, Maria Del Carmen; Turk-Kubo, Kendra A

    2016-12-20

    Nitrogen fixation - the reduction of dinitrogen (N2) gas to biologically available nitrogen (N) - is an important source of N for terrestrial and aquatic ecosystems. In terrestrial environments, N2-fixing symbioses involve multicellular plants, but in the marine environment these symbioses occur with unicellular planktonic algae. An unusual symbiosis between an uncultivated unicellular cyanobacterium (UCYN-A) and a haptophyte picoplankton alga was recently discovered in oligotrophic oceans. UCYN-A has a highly reduced genome, and exchanges fixed N for fixed carbon with its host. This symbiosis bears some resemblance to symbioses found in freshwater ecosystems. UCYN-A shares many core genes with the 'spheroid bodies' of Epithemia turgida and the endosymbionts of the amoeba Paulinella chromatophora. UCYN-A is widely distributed, and has diversified into a number of sublineages that could be ecotypes. Many questions remain regarding the physical and genetic mechanisms of the association, but UCYN-A is an intriguing model for contemplating the evolution of N2-fixing organelles.

  19. Modeling culture profiles of the heterocystous N2-fixing cyanobacterium Anabaena flos-aquae.

    PubMed

    Pinzon, Neissa M; Ju, Lu-Kwang

    2006-01-01

    Heterocyst differentiation is a unique feature of nitrogen-fixing cyanobacteria, potentially important for photobiological hydrogen production. Despite the significant advances in genetic investigation on heterocyst differentiation, there were no quantitative culture-level models that describe the effects of cellular activities and cultivation conditions on the heterocyst differentiation. Such a model was developed in this study, incorporating photosynthetic growth of vegetative cells, heterocyst differentiation, self-shading effect on light penetration, and nitrogen fixation. The model parameters were determined by fitting experimental results from the growth of the heterocystous cyanobacterium Anabaena flos-aquae CCAP 1403/13f in media without and with different nitrate concentrations and under continuous illumination of white light at different light intensities (2, 5, 10, 17, 20 and 50 microE m-2 s-1). The model describes the experimental profiles well and gives reasonable predictions even for the transition of growth from that on external N source to that via nitrogen fixation, responding to the change in external N concentrations. The significance and implications of the best-fit values of the model parameters are discussed.

  20. Surplus Photosynthetic Antennae Complexes Underlie Diagnostics of Iron Limitation in a Cyanobacterium

    PubMed Central

    Schrader, Paul S.; Milligan, Allen J.; Behrenfeld, Michael J.

    2011-01-01

    Chlorophyll fluorescence from phytoplankton provides a tool to assess iron limitation in the oceans, but the physiological mechanism underlying the fluorescence response is not understood. We examined fluorescence properties of the model cyanobacterium Synechocystis PCC6803 and a ΔisiA knock-out mutant of the same species grown under three culture conditions which simulate nutrient conditions found in the open ocean: (1) nitrate and iron replete, (2) limiting-iron and high-nitrate, representative of natural high-nitrate, low-chlorophyll regions, and (3) iron and nitrogen co-limiting. We show that low variable fluorescence, a key diagnostic of iron limitation, results from synthesis of antennae complexes far in excess of what can be accommodated by the iron-restricted pool of photosynthetic reaction centers. Under iron and nitrogen co-limiting conditions, there are no excess antennae complexes and variable fluorescence is high. These results help to explain the well-established fluorescence characteristics of phytoplankton in high-nutrient, low-chlorophyll ocean regions, while also accounting for the lack of these properties in low-iron, low-nitrogen regions. Importantly, our results complete the link between unique molecular consequences of iron stress in phytoplankton and global detection of iron stress in natural populations from space. PMID:21533084

  1. Ecological specialization in a spatially structured population of the thermophilic cyanobacterium Mastigocladus laminosus.

    PubMed

    Miller, Scott R; Williams, Carin; Strong, Aaron L; Carvey, Darla

    2009-02-01

    Laboratory evolution experiments suggest the potential for microbial populations to contribute significant ecological variation to ecosystems, yet the functional importance of genetic diversity within natural populations of microorganisms is largely unknown. Here, we investigated the distribution of genetic and phenotypic variation for a population of the cyanobacterium Mastigocladus laminosus distributed along the temperature gradient of White Creek, Yellowstone NP. A total of 153 laboratory strains were directly isolated from five sites with mean annual temperatures ranging between 39 and 54 degrees C. Genetic characterization at four nitrogen metabolism genes identified 15 closely related lineages in the population sample. These lineages were distributed nonrandomly along White Creek, but the observed geographic structure could not be explained by limited dispersal capabilities. Temperature performance experiments with six M. laminosus lineages that maximized their respective relative abundances at different positions along the gradient provided evidence for niche differentiation within the population. Niche differentiation included a tradeoff in performance at high and low temperatures, respectively. The physiological variation of these lineages in laboratory culture was generally well matched to the prevailing temperature conditions experienced by these organisms in situ. These results suggest that sympatric diversification along an ecological selection gradient can be a potent source of evolutionary innovation in microbial populations.

  2. Refolding and Enzyme Kinetic Studies on the Ferrochelatase of the Cyanobacterium Synechocystis sp. PCC 6803

    PubMed Central

    Storm, Patrik; Tibiletti, Tania; Hall, Michael; Funk, Christiane

    2013-01-01

    Heme is a cofactor for proteins participating in many important cellular processes, including respiration, oxygen metabolism and oxygen binding. The key enzyme in the heme biosynthesis pathway is ferrochelatase (protohaem ferrolyase, EC 4.99.1.1), which catalyzes the insertion of ferrous iron into protoporphyrin IX. In higher plants, the ferrochelatase enzyme is localized not only in mitochondria, but also in chloroplasts. The plastidic type II ferrochelatase contains a C-terminal chlorophyll a/b (CAB) motif, a conserved hydrophobic stretch homologous to the CAB domain of plant light harvesting proteins and light-harvesting like proteins. This type II ferrochelatase, found in all photosynthetic organisms, is presumed to have evolved from the cyanobacterial ferrochelatase. Here we describe a detailed enzymological study on recombinant, refolded and functionally active type II ferrochelatase (FeCh) from the cyanobacterium Synechocystis sp. PCC 6803. A protocol was developed for the functional refolding and purification of the recombinant enzyme from inclusion bodies, without truncation products or soluble aggregates. The refolded FeCh is active in its monomeric form, however, addition of an N-terminal His6-tag has significant effects on its enzyme kinetics. Strikingly, removal of the C-terminal CAB-domain led to a greatly increased turnover number, kcat, compared to the full length protein. While pigments isolated from photosynthetic membranes decrease the activity of FeCh, direct pigment binding to the CAB domain of FeCh was not evident. PMID:23390541

  3. Biochemical Studies of the Lagunamides, Potent Cytotoxic Cyclic Depsipeptides from the Marine Cyanobacterium Lyngbya majuscula

    PubMed Central

    Tripathi, Ashootosh; Fang, Wanru; Leong, David Tai; Tan, Lik Tong

    2012-01-01

    Lagunamides A (1) and B (2) are potent cytotoxic cyclic depsipeptides isolated from the filamentous marine cyanobacterium, Lyngbya majuscula, from Pulau Hantu, Singapore. These compounds are structurally related to the aurilide-class of molecules, which have been reported to possess exquisite antiproliferative activities against cancer cells. The present study presents preliminary findings on the selectivity of lagunamides against various cancer cell lines as well as their mechanism of action by studying their effects on programmed cell death or apoptosis. Lagunamide A exhibited a selective growth inhibitory activity against a panel of cancer cell lines, including P388, A549, PC3, HCT8, and SK-OV3 cells, with IC50 values ranging from 1.6 nM to 6.4 nM. Morphological studies showed blebbing at the surface of cancer cells as well as cell shrinkage accompanied by loss of contact with the substratum and neighboring cells. Biochemical studies using HCT8 and MCF7 cancer cells suggested that the cytotoxic effect of 1 and 2 might act via induction of mitochondrial mediated apoptosis. Data presented in this study warrants further investigation on the mode of action and underscores the importance of the lagunamides as potential anticancer agents. PMID:22822361

  4. Species delimitation in asexual insects of economic importance: The case of black scale (Parasaissetia nigra), a cosmopolitan parthenogenetic pest scale insect.

    PubMed

    Lin, Yen-Po; Edwards, Robert D; Kondo, Takumasa; Semple, Thomas L; Cook, Lyn G

    2017-01-01

    Asexual lineages provide a challenge to species delimitation because species concepts either have little biological meaning for them or are arbitrary, since every individual is monophyletic and reproductively isolated from all other individuals. However, recognition and naming of asexual species is important to conservation and economic applications. Some scale insects are widespread and polyphagous pests of plants, and several species have been found to comprise cryptic species complexes. Parasaissetia nigra (Nietner, 1861) (Hemiptera: Coccidae) is a parthenogenetic, cosmopolitan and polyphagous pest that feeds on plant species from more than 80 families. Here, we implement multiple approaches to assess the species status of P. nigra, including coalescence-based analyses of mitochondrial and nuclear genes, and ecological niche modelling. Our results indicate that the sampled specimens of P. nigra should be considered to comprise at least two ecotypes (or "species") that are ecologically differentiated, particularly in relation to temperature and moisture. The presence of more than one ecotype under the current concept of P. nigra has implications for biosecurity because the geographic extent of each type is not fully known: some countries may currently have only one of the biotypes. Introduction of additional lineages could expand the geographic extent of damage by the pest in some countries.

  5. Species delimitation in asexual insects of economic importance: The case of black scale (Parasaissetia nigra), a cosmopolitan parthenogenetic pest scale insect

    PubMed Central

    Edwards, Robert D.; Kondo, Takumasa; Semple, Thomas L.; Cook, Lyn G.

    2017-01-01

    Asexual lineages provide a challenge to species delimitation because species concepts either have little biological meaning for them or are arbitrary, since every individual is monophyletic and reproductively isolated from all other individuals. However, recognition and naming of asexual species is important to conservation and economic applications. Some scale insects are widespread and polyphagous pests of plants, and several species have been found to comprise cryptic species complexes. Parasaissetia nigra (Nietner, 1861) (Hemiptera: Coccidae) is a parthenogenetic, cosmopolitan and polyphagous pest that feeds on plant species from more than 80 families. Here, we implement multiple approaches to assess the species status of P. nigra, including coalescence-based analyses of mitochondrial and nuclear genes, and ecological niche modelling. Our results indicate that the sampled specimens of P. nigra should be considered to comprise at least two ecotypes (or "species") that are ecologically differentiated, particularly in relation to temperature and moisture. The presence of more than one ecotype under the current concept of P. nigra has implications for biosecurity because the geographic extent of each type is not fully known: some countries may currently have only one of the biotypes. Introduction of additional lineages could expand the geographic extent of damage by the pest in some countries. PMID:28459805

  6. The abattoir condemnation of meat because of parasitic infection, and its economic importance: results of a retrospective study in north-eastern Iran.

    PubMed

    Borji, H; Parandeh, S

    2010-12-01

    In nine districts in the north of Khorasan province, in north-eastern Iran, a 5-year retrospective study was carried out to determine the prevalences, in livestock slaughtered in abattoirs, of the parasitic infections responsible for the condemnation of the animals' carcasses and viscera (and the economic importance of such infections in terms of lost meat and offal). Between 20 March 2005 and 19 March 2010, 436,620 animals (45,360 cattle, 275,439 sheep, 115,674 goats and 147 camels) were slaughtered in the study area and the livers of 30,207 (6.9%), the lungs of 23,259 (5.3%) and the carcasses of 1072 (0.2%) of these animals were condemned. Almost all (92.4%) of the condemned livers, most (68.9%) of the condemned lungs but only 10.8% of the condemned carcasses were rejected because of parasitic infection. The parasitic lesions observed in the condemned livers were attributed to Echinococcus granulosus, Fasciola hepatica and/or Dicrocoelium dendriticum (cattle, sheep and goats) or entirely to E. granulosus (camels). All the parasitic lesions observed in the condemned lungs (which also came from cattle, sheep, goats and camels) were attributed to E. granulosus. Sarcocystis cysts and/or Taenia cysticerci were found in ovine muscle while only Taenia cysticerci were detected in bovine muscle (no parasitic lesions were observed in the muscles of the goats and camels). Parasites were responsible for 80.8% of the condemned organs or carcasses, and the value of the food lost because of parasite-related condemnation (based on market prices in 2010) was estimated to be U.S.$421,826 (U.S.$47,980 for cattle, U.S.$316,344.0 for sheep, U.S.$57,372 for goats and U.S.$130 for camels). The parasites contributing most to the condemnation of otherwise marketable organs and muscles were E. granulosus (52.2%) and D. dendriticum flukes (29.5%). These parasites clearly remain too common and cause considerable economic loss in Khorasan and, presumably, other areas of Iran.

  7. Production of the neurotoxin BMAA by a marine cyanobacterium.

    PubMed

    Banack, Sandra Anne; Johnson, Holly E; Cheng, Ran; Cox, Paul Alan

    2007-12-06

    Diverse species of cyanobacteria have recently been discovered to produce the neurotoxic non-protein amino acid beta-methylamino-L-alanine (BMAA). In Guam, BMAA has been studied as a possible environmental toxin in the diets of indigenous Chamorro people known to have high levels of Amyotrophic Lateral Sclerosis/ Parkinsonism Dementia Complex (ALS/PDC). BMAA has been found to accumulate in brain tissues of patients with progressive neurodegenerative illness in North America. In Guam, BMAA was found to be produced by endosymbiotic cyanobacteria of the genus Nostoc which live in specialized cycad roots. We here report detection of BMAA in laboratory cultures of a free-living marine species of Nostoc. We successfully detected BMAA in this marine species of Nostoc with five different methods: HPLC-FD, UPLC-UV, Amino Acid Analyzer, LC/MS, and Triple Quadrupole LC/MS/MS. This consensus of five different analytical methods unequivocally demonstrates the presence of BMAA in this marine cyanobacterium. Since protein-associated BMAA can accumulate in increasing levels within food chains, it is possible that biomagnification of BMAA could occur in marine ecosystems similar to the biomagnification of BMAA in terrestrial ecosystems. Production of BMAA by marine cyanobacteria may represent another route of human exposure to BMAA. Since BMAA at low concentrations causes the death of motor neurons, low levels of BMAA exposure may trigger motor neuron disease in genetically vulnerable individuals.

  8. Export of Extracellular Polysaccharides Modulates Adherence of the Cyanobacterium Synechocystis

    SciTech Connect

    Fisher, ML; Allen, R; Luo, YQ; Curtiss, R

    2013-09-10

    The field of cyanobacterial biofuel production is advancing rapidly, yet we know little of the basic biology of these organisms outside of their photosynthetic pathways. We aimed to gain a greater understanding of how the cyanobacterium Synechocystis PCC 6803 (Synechocystis, hereafter) modulates its cell surface. Such understanding will allow for the creation of mutants that autoflocculate in a regulated way, thus avoiding energy intensive centrifugation in the creation of biofuels. We constructed mutant strains lacking genes predicted to function in carbohydrate transport or synthesis. Strains with gene deletions of slr0977 (predicted to encode a permease component of an ABC transporter), slr0982 (predicted to encode an ATP binding component of an ABC transporter) and slr1610 (predicted to encode a methyltransferase) demonstrated flocculent phenotypes and increased adherence to glass. Upon bioinformatic inspection, the gene products of slr0977, slr0982, and slr1610 appear to function in O-antigen (OAg) transport and synthesis. However, the analysis provided here demonstrated no differences between OAg purified from wild-type and mutants. However, exopolysaccharides (EPS) purified from mutants were altered in composition when compared to wild-type. Our data suggest that there are multiple means to modulate the cell surface of Synechocystis by disrupting different combinations of ABC transporters and/or glycosyl transferases. Further understanding of these mechanisms may allow for the development of industrially and ecologically useful strains of cyanobacteria. Additionally, these data imply that many cyanobacterial gene products may possess as-yet undiscovered functions, and are meritorious of further study.

  9. Ribulose diphosphate carboxylase of the cyanobacterium Spirulina platensis

    SciTech Connect

    Terekhova, I.V.; Chernyad'ev, I.I.; Doman, N.G.

    1986-11-20

    The ribulose diphosphate (RDP) carboxylase activity of the cyanobacterium Spirulina platensis is represented by two peaks when a cell homogenate is centrifuged in a sucrose density gradient. In the case of differential centrifugation (40,000 g, 1 h), the activity of the enzyme was distributed between the supernatant liquid (soluble form) and the precipitate (carboxysomal form). From the soluble fraction, in which 80-95% of the total activity of the enzyme is concentrated, electrophoretically homogeneous RDP carboxylase was isolated by precipitation with ammonium sulfate and centrifugation in a sucrose density gradient. The purified enzyme possessed greater electrophoretic mobility in comparison with the RDP carboxylase of beans Vicia faba. The molecular weight of the enzyme, determined by gel filtration, was 450,000. The enzyme consists of monotypic subunits with a molecular weight of 53,000. The small subunits were not detected in electrophoresis in polyacrylamide gel in the presence of SDS after fixation and staining of the gels by various methods.

  10. Sucrose secreted by the engineered cyanobacterium and its fermentability

    NASA Astrophysics Data System (ADS)

    Duan, Yangkai; Luo, Quan; Liang, Feiyan; Lu, Xuefeng

    2016-10-01

    The unicellular cyanobacterium, Synechococcus elongatus PCC 7942 (Syn7942), synthesizes sucrose as the only compatible solute under salt stress. A series of engineered Syn7942 strains for sucrose production were constructed. The overexpression of the native sps (encoding a natively fused protein of sucrose phosphate synthase SPS and sucrose phosphate phosphatase SPP) in Syn7942 wild type caused a 93% improvement of sucrose productivity. The strain FL130 co-overexpressing sps and cscB (encoding a sucrose transporter) exhibited a 74% higher extracellular sucrose production than that overexpressing cscB only. Both results showed the significant improvement of sucrose productivity by the double functional protein SPS-SPP. Afterwards, FL130 was cultivated under a modified condition, and the cell-free culture medium containing 1.5 g L-1 sucrose was pre-treated with an acid hydrolysis technique. Cultivated with the neutralized hydrolysates as the starting media, two widely used microorganisms, Escherichia coli and Saccharomyces cerevisiae, showed a comparable growth with that in the control media supplemented with glucose. These results clearly demonstrated that the cell-free culture of sucrose-secreting cyanobacteria can be applied as starting media in microbial cultivation.

  11. Construction of a cyanobacterium synthesizing cyclopropane fatty acids.

    PubMed

    Machida, Shuntaro; Shiraiwa, Yoshihiro; Suzuki, Iwane

    2016-09-01

    Microalgae have received much attention as a next-generation source of biomass energy. However, most of the fatty acids (FAs) from microalgae are multiply unsaturated; thus, the biofuels derived from them are fluid, but vulnerable to oxidation. In this study, we attempted to synthesize cyclopropane FAs in the cyanobacterium Synechocystis sp. PCC 6803 by expressing the cfa gene for cyclopropane FA synthase from Escherichia coli with the aim of producing FAs that are fluid and stable in response to oxidization. We successfully synthesized cyclopropane FAs in Synechocystis with a yield of ~30% of total FAs. Growth of the transformants was altered, particularly at low temperatures, but photosynthesis and respiration were not significantly affected. C16:1(∆9) synthesis in the desA(-)/desD(-) strain by expression of the desC2 gene for sn-2 specific ∆9 desaturase positively affected growth at low temperatures via promotion of various cellular processes, with the exceptions of photosynthesis and respiration. Estimation of the apparent activities of desaturases suggested that some acyl-lipid desaturases might recognize the lipid side chain.

  12. Potential effects of UV radiation on photosynthetic structures of the bloom-forming cyanobacterium Cylindrospermopsis raciborskii CYRF-01

    PubMed Central

    Noyma, Natália P.; Silva, Thiago P.; Chiarini-Garcia, Hélio; Amado, André M.; Roland, Fábio; Melo, Rossana C. N.

    2015-01-01

    Cyanobacteria are aquatic photosynthetic microorganisms. While of enormous ecological importance, they have also been linked to human and animal illnesses around the world as a consequence of toxin production by some species. Cylindrospermopsis raciborskii, a filamentous nitrogen-fixing cyanobacterium, has attracted considerable attention due to its potential toxicity and ecophysiological adaptability. We investigated whether C. raciborskii could be affected by ultraviolet (UV) radiation. Non-axenic cultures of C. raciborskii were exposed to three UV treatments (UVA, UVB, or UVA + UVB) over a 6 h period, during which cell concentration, viability and ultrastructure were analyzed. UVA and UVA + UVB treatments showed significant negative effects on cell concentration (decreases of 56.4 and 64.3%, respectively). This decrease was directly associated with cell death as revealed by a cell viability fluorescent probe. Over 90% of UVA + UVB- and UVA-treated cells died. UVB did not alter cell concentration, but reduced cell viability in almost 50% of organisms. Transmission electron microscopy (TEM) revealed a drastic loss of thylakoids, membranes in which cyanobacteria photosystems are localized, after all treatments. Moreover, other photosynthetic- and metabolic-related structures, such as accessory pigments and polyphosphate granules, were damaged. Quantitative TEM analyses revealed a 95.8% reduction in cell area occupied by thylakoids after UVA treatment, and reduction of 77.6 and 81.3% after UVB and UVA + UVB treatments, respectively. Results demonstrated clear alterations in viability and photosynthetic structures of C. raciborskii induced by various UV radiation fractions. This study facilitates our understanding of the subcellular organization of this cyanobacterium species, identifies specific intracellular targets of UVA and UVB radiation and reinforces the importance of UV radiation as an environmental stressor. PMID:26579108

  13. Global insights into high temperature and drought stress regulated genes by RNA-Seq in economically important oilseed crop Brassica juncea.

    PubMed

    Bhardwaj, Ankur R; Joshi, Gopal; Kukreja, Bharti; Malik, Vidhi; Arora, Priyanka; Pandey, Ritu; Shukla, Rohit N; Bankar, Kiran G; Katiyar-Agarwal, Surekha; Goel, Shailendra; Jagannath, Arun; Kumar, Amar; Agarwal, Manu

    2015-01-21

    Brassica juncea var. Varuna is an economically important oilseed crop of family Brassicaceae which is vulnerable to abiotic stresses at specific stages in its life cycle. Till date no attempts have been made to elucidate genome-wide changes in its transcriptome against high temperature or drought stress. To gain global insights into genes, transcription factors and kinases regulated by these stresses and to explore information on coding transcripts that are associated with traits of agronomic importance, we utilized a combinatorial approach of next generation sequencing and de-novo assembly to discover B. juncea transcriptome associated with high temperature and drought stresses. We constructed and sequenced three transcriptome libraries namely Brassica control (BC), Brassica high temperature stress (BHS) and Brassica drought stress (BDS). More than 180 million purity filtered reads were generated which were processed through quality parameters and high quality reads were assembled de-novo using SOAPdenovo assembler. A total of 77750 unique transcripts were identified out of which 69,245 (89%) were annotated with high confidence. We established a subset of 19110 transcripts, which were differentially regulated by either high temperature and/or drought stress. Furthermore, 886 and 2834 transcripts that code for transcription factors and kinases, respectively, were also identified. Many of these were responsive to high temperature, drought or both stresses. Maximum number of up-regulated transcription factors in high temperature and drought stress belonged to heat shock factors (HSFs) and dehydration responsive element-binding (DREB) families, respectively. We also identified 239 metabolic pathways, which were perturbed during high temperature and drought treatments. Analysis of gene ontologies associated with differentially regulated genes forecasted their involvement in diverse biological processes. Our study provides first comprehensive discovery of B. juncea

  14. The slugs of Britain and Ireland: undetected and undescribed species increase a well-studied, economically important fauna by more than 20%.

    PubMed

    Rowson, Ben; Anderson, Roy; Turner, James A; Symondson, William O C

    2014-01-01

    The slugs of Britain and Ireland form a well-studied fauna of economic importance. They include many widespread European species that are introduced elsewhere (at least half of the 36 currently recorded British species are established in North America, for example). To test the contention that the British and Irish fauna consists of 36 species, and to verify the identity of each, a species delimitation study was conducted based on a geographically wide survey. Comparisons between mitochondrial DNA (COI, 16S), nuclear DNA (ITS-1) and morphology were investigated with reference to interspecific hybridisation. Species delimitation of the fauna produced a primary species hypothesis of 47 putative species. This was refined to a secondary species hypothesis of 44 species by integration with morphological and other data. Thirty six of these correspond to the known fauna (two species in Arion subgenus Carinarion were scarcely distinct and Arion (Mesarion) subfuscus consisted of two near-cryptic species). However, by the same criteria a further eight previously undetected species (22% of the fauna) are established in Britain and/or Ireland. Although overlooked, none are strictly morphologically cryptic, and some appear previously undescribed. Most of the additional species are probably accidentally introduced, and several are already widespread in Britain and Ireland (and thus perhaps elsewhere). At least three may be plant pests. Some evidence was found for interspecific hybridisation among the large Arion species (although not involving A. flagellus) and more unexpectedly in species pairs in Deroceras (Agriolimacidae) and Limacus (Limacidae). In the latter groups, introgression appears to have occurred in one direction only, with recently-invading lineages becoming common at the expense of long-established or native ones. The results show how even a well-studied, macroscopic fauna can be vulnerable to cryptic and undetected invasions and changes.

  15. A Phylogenetic Analysis of Chloroplast Genomes Elucidates the Relationships of the Six Economically Important Brassica Species Comprising the Triangle of U

    PubMed Central

    Li, Peirong; Zhang, Shujiang; Li, Fei; Zhang, Shifan; Zhang, Hui; Wang, Xiaowu; Sun, Rifei; Bonnema, Guusje; Borm, Theo J. A.

    2017-01-01

    The Brassica genus comprises many economically important worldwide cultivated crops. The well-established model of the Brassica genus, U’s triangle, consists of three basic diploid plant species (Brassica rapa, Brassica oleracea, and Brassica nigra) and three amphidiploid species (Brassica napus, Brassica juncea, and Brassica carinata) that arose through interspecific hybridizations. Despite being extensively studied because of its commercial relevance, several aspects of the origin of the Brassica species and the relationships within and among these six species still remain open questions. Here, we successfully de novo assembled 60 complete chloroplast genomes of Brassica genotypes of all six species. A complete map of the single nucleotide variants and insertions and deletions in the chloroplast genomes of different Brassica species was produced. The chloroplast genome consists of a Large and a Small Single Copy (LSC and SSC) region between two inverted repeats, and while these regions of chloroplast genomes have very different molecular evolutionary rates, phylogenetic analyses of different regions yielded no contradicting topologies and separated the Brassica genus into four clades. B. carinata and B. juncea share their chloroplast genome with one of their hybridization donors B. nigra and B. rapa, respectively, which fits the U model. B. rapa, surprisingly, shows evidence of two types of chloroplast genomes, with one type specific to some Italian broccoletto accessions. B. napus clearly has evidence for two independent hybridization events, as it contains either B. rapa chloroplast genomes. The divergence estimation suggests that B. nigra and B. carinata diverged from the main Brassica clade 13.7 million years ago (Mya), while B. rapa and B. oleracea diverged at 2.18 Mya. The use of the complete chloroplast DNA sequence not only provides insights into comparative genome analysis but also paves the way for a better understanding of the phylogenetic

  16. The Slugs of Britain and Ireland: Undetected and Undescribed Species Increase a Well-Studied, Economically Important Fauna by More Than 20%

    PubMed Central

    Rowson, Ben; Anderson, Roy; Turner, James A.; Symondson, William O. C.

    2014-01-01

    The slugs of Britain and Ireland form a well-studied fauna of economic importance. They include many widespread European species that are introduced elsewhere (at least half of the 36 currently recorded British species are established in North America, for example). To test the contention that the British and Irish fauna consists of 36 species, and to verify the identity of each, a species delimitation study was conducted based on a geographically wide survey. Comparisons between mitochondrial DNA (COI, 16S), nuclear DNA (ITS-1) and morphology were investigated with reference to interspecific hybridisation. Species delimitation of the fauna produced a primary species hypothesis of 47 putative species. This was refined to a secondary species hypothesis of 44 species by integration with morphological and other data. Thirty six of these correspond to the known fauna (two species in Arion subgenus Carinarion were scarcely distinct and Arion (Mesarion) subfuscus consisted of two near-cryptic species). However, by the same criteria a further eight previously undetected species (22% of the fauna) are established in Britain and/or Ireland. Although overlooked, none are strictly morphologically cryptic, and some appear previously undescribed. Most of the additional species are probably accidentally introduced, and several are already widespread in Britain and Ireland (and thus perhaps elsewhere). At least three may be plant pests. Some evidence was found for interspecific hybridisation among the large Arion species (although not involving A. flagellus) and more unexpectedly in species pairs in Deroceras (Agriolimacidae) and Limacus (Limacidae). In the latter groups, introgression appears to have occurred in one direction only, with recently-invading lineages becoming common at the expense of long-established or native ones. The results show how even a well-studied, macroscopic fauna can be vulnerable to cryptic and undetected invasions and changes. PMID:24740519

  17. Recent advances in the cryopreservation of shoot-derived germplasm of economically important fruit trees of Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis.

    PubMed

    Benelli, Carla; De Carlo, Anna; Engelmann, Florent

    2013-01-01

    This paper presents the advances made over the last decade in cryopreservation of economically important vegetatively propagated fruit trees. Cryopreservation protocols have been established using both dormant buds sampled on field-grown plants and shoot tips sampled on in vitro plantlets. In the case of dormant buds, scions are partially dehydrated by storage at -5 °C, and then cooled slowly to -30 °C using low cooling rates (c.a. 1 °C/h) before immersion in liquid nitrogen. After slow rewarming and rehydration of samples, regrowth takes place either through grafting of buds on rootstocks or excision of apices and inoculation in vitro. In the case of shoot tips of in vitro plantlets, the cryopreservation techniques employed are the following: controlled rate cooling procedures involving slow prefreezing followed by immersion in liquid nitrogen or vitrification-based procedures including encapsulation-dehydration, vitrification, encapsulation-vitrification and droplet-vitrification. The current status of cryopreservation for a series of fruit tree species including Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis is presented. Routine application of cryopreservation for long-term germplasm storage in genebanks is currently limited to apple and pear, for which large cryopreserved collections have been established at NCGRP, Fort Collins (USA), using dormant buds and in vitro shoot tips, respectively. However, there are a growing number of examples of pilot scale testing experiments under way for different species in various countries. Progress in the further development and application of cryopreservation techniques will be made through a better understanding of the mechanisms involved in the induction of tolerance to dehydration and cryopreservation in frozen explants.

  18. An integrated genetic map based on four mapping populations and quantitative trait loci associated with economically important traits in watermelon (Citrullus lanatus).

    PubMed

    Ren, Yi; McGregor, Cecilia; Zhang, Yan; Gong, Guoyi; Zhang, Haiying; Guo, Shaogui; Sun, Honghe; Cai, Wantao; Zhang, Jie; Xu, Yong

    2014-01-20

    Modern watermelon (Citrullus lanatus L.) cultivars share a narrow genetic base due to many years of selection for desirable horticultural qualities. Wild subspecies within C. lanatus are important potential sources of novel alleles for watermelon breeding, but successful trait introgression into elite cultivars has had limited success. The application of marker assisted selection (MAS) in watermelon is yet to be realized, mainly due to the past lack of high quality genetic maps. Recently, a number of useful maps have become available, however these maps have few common markers, and were constructed using different marker sets, thus, making integration and comparative analysis among maps difficult. The objective of this research was to use single-nucleotide polymorphism (SNP) anchor markers to construct an integrated genetic map for C. lanatus. Under the framework of the high density genetic map, an integrated genetic map was constructed by merging data from four independent mapping experiments using a genetically diverse array of parental lines, which included three subspecies of watermelon. The 698 simple sequence repeat (SSR), 219 insertion-deletion (InDel), 36 structure variation (SV) and 386 SNP markers from the four maps were used to construct an integrated map. This integrated map contained 1339 markers, spanning 798 cM with an average marker interval of 0.6 cM. Fifty-eight previously reported quantitative trait loci (QTL) for 12 traits in these populations were also integrated into the map. In addition, new QTL identified for brix, fructose, glucose and sucrose were added. Some QTL associated with economically important traits detected in different genetic backgrounds mapped to similar genomic regions of the integrated map, suggesting that such QTL are responsible for the phenotypic variability observed in a broad array of watermelon germplasm. The integrated map described herein enhances the utility of genomic tools over previous watermelon genetic maps. A

  19. An integrated genetic map based on four mapping populations and quantitative trait loci associated with economically important traits in watermelon (Citrullus lanatus)

    PubMed Central

    2014-01-01

    Background Modern watermelon (Citrullus lanatus L.) cultivars share a narrow genetic base due to many years of selection for desirable horticultural qualities. Wild subspecies within C. lanatus are important potential sources of novel alleles for watermelon breeding, but successful trait introgression into elite cultivars has had limited success. The application of marker assisted selection (MAS) in watermelon is yet to be realized, mainly due to the past lack of high quality genetic maps. Recently, a number of useful maps have become available, however these maps have few common markers, and were constructed using different marker sets, thus, making integration and comparative analysis among maps difficult. The objective of this research was to use single-nucleotide polymorphism (SNP) anchor markers to construct an integrated genetic map for C. lanatus. Results Under the framework of the high density genetic map, an integrated genetic map was constructed by merging data from four independent mapping experiments using a genetically diverse array of parental lines, which included three subspecies of watermelon. The 698 simple sequence repeat (SSR), 219 insertion-deletion (InDel), 36 structure variation (SV) and 386 SNP markers from the four maps were used to construct an integrated map. This integrated map contained 1339 markers, spanning 798 cM with an average marker interval of 0.6 cM. Fifty-eight previously reported quantitative trait loci (QTL) for 12 traits in these populations were also integrated into the map. In addition, new QTL identified for brix, fructose, glucose and sucrose were added. Some QTL associated with economically important traits detected in different genetic backgrounds mapped to similar genomic regions of the integrated map, suggesting that such QTL are responsible for the phenotypic variability observed in a broad array of watermelon germplasm. Conclusions The integrated map described herein enhances the utility of genomic tools over

  20. Gene transfer to the desiccation-tolerant cyanobacterium Chroococcidiopsis.

    PubMed

    Billi, D; Friedmann, E I; Helm, R F; Potts, M

    2001-04-01

    The coccoid cyanobacterium Chroococcidiopsis dominates microbial communities in the most extreme arid hot and cold deserts. These communities withstand constraints that result from multiple cycles of drying and wetting and/or prolonged desiccation, through mechanisms which remain poorly understood. Here we describe the first system for genetic manipulation of Chroococcidiopsis. Plasmids pDUCA7 and pRL489, based on the pDU1 replicon of Nostoc sp. strain PCC 7524, were transferred to different isolates of Chroococcidiopsis via conjugation and electroporation. This report provides the first evidence that pDU1 replicons can be maintained in cyanobacteria other than Nostoc and Anabaena. Following conjugation, both plasmids replicated in Chroococcidiopsis sp. strains 029, 057, and 123 but not in strains 171 and 584. Both plasmids were electroporated into strains 029 and 123 but not into strains 057, 171, and 584. Expression of P(psbA)-luxAB on pRL489 was visualized through in vivo luminescence. Efficiencies of conjugative transfer for pDUCA7 and pRL489 into Chroococcidiopsis sp. strain 029 were approximately 10(-2) and 10(-4) transconjugants per recipient cell, respectively. Conjugative transfer occurred with a lower efficiency into strains 057 and 123. Electrotransformation efficiencies of about 10(-4) electrotransformants per recipient cell were achieved with strains 029 and 123, using either pDUCA7 or pRL489. Extracellular deoxyribonucleases were associated with each of the five strains. Phylogenetic analysis, based upon the V6 to V8 variable regions of 16S rRNA, suggests that desert strains 057, 123, 171, and 029 are distinct from the type species strain Chroococcidiopsis thermalis PCC 7203. The high efficiency of conjugative transfer of Chroococcidiopsis sp. strain 029, from the Negev Desert, Israel, makes this a suitable experimental strain for genetic studies on desiccation tolerance.

  1. Export of Extracellular Polysaccharides Modulates Adherence of the Cyanobacterium Synechocystis

    PubMed Central

    Fisher, Michael L.; Allen, Rebecca; Luo, Yingqin; Curtiss, Roy

    2013-01-01

    The field of cyanobacterial biofuel production is advancing rapidly, yet we know little of the basic biology of these organisms outside of their photosynthetic pathways. We aimed to gain a greater understanding of how the cyanobacterium Synechocystis PCC 6803 (Synechocystis, hereafter) modulates its cell surface. Such understanding will allow for the creation of mutants that autoflocculate in a regulated way, thus avoiding energy intensive centrifugation in the creation of biofuels. We constructed mutant strains lacking genes predicted to function in carbohydrate transport or synthesis. Strains with gene deletions of slr0977 (predicted to encode a permease component of an ABC transporter), slr0982 (predicted to encode an ATP binding component of an ABC transporter) and slr1610 (predicted to encode a methyltransferase) demonstrated flocculent phenotypes and increased adherence to glass. Upon bioinformatic inspection, the gene products of slr0977, slr0982, and slr1610 appear to function in O-antigen (OAg) transport and synthesis. However, the analysis provided here demonstrated no differences between OAg purified from wild-type and mutants. However, exopolysaccharides (EPS) purified from mutants were altered in composition when compared to wild-type. Our data suggest that there are multiple means to modulate the cell surface of Synechocystis by disrupting different combinations of ABC transporters and/or glycosyl transferases. Further understanding of these mechanisms may allow for the development of industrially and ecologically useful strains of cyanobacteria. Additionally, these data imply that many cyanobacterial gene products may possess as-yet undiscovered functions, and are meritorious of further study. PMID:24040267

  2. Arsenic biotransformation by a cyanobacterium Nostoc sp. PCC 7120.

    PubMed

    Xue, Xi-Mei; Yan, Yu; Xiong, Chan; Raber, Georg; Francesconi, Kevin; Pan, Ting; Ye, Jun; Zhu, Yong-Guan

    2017-09-01

    Nostoc sp. PCC 7120 (Nostoc), a typical filamentous cyanobacterium ubiquitous in aquatic system, is recognized as a model organism to study prokaryotic cell differentiation and nitrogen fixation. In this study, Nostoc cells incubated with arsenite (As(III)) for two weeks were extracted with dichloromethane/methanol (DCM/MeOH) and the extract was partitioned between water and DCM. Arsenic species in aqueous and DCM layers were determined using high performance liquid chromatography - inductively coupled plasma mass spectrometer/electrospray tandem mass spectrometry (HPLC-ICPMS/ESIMSMS). In addition to inorganic arsenic (iAs), the aqueous layer also contained monomethylarsonate (MAs(V)), dimethylarsinate (DMAs(V)), and the two arsenosugars, namely a glycerol arsenosugar (Oxo-Gly) and a phosphate arsenosugar (Oxo-PO4). Two major arsenosugar phospholipids (AsSugPL982 and AsSugPL984) were detected in DCM fraction. Arsenic in the growth medium was also investigated by HPLC/ICPMS and shown to be present mainly as the inorganic forms As(III) and As(V) accounting for 29%-38% and 29%-57% of the total arsenic respectively. The total arsenic of methylated arsenic, arsenosugars, and arsenosugar phospholipids in Nostoc cells with increasing As(III) exposure were not markedly different, indicating that the transformation to organoarsenic in Nostoc was not dependent on As(III) concentration in the medium. Our results provide new insights into the role of cyanobacteria in the biogeochemical cycling of arsenic. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Ferredoxin and flavodoxin from the cyanobacterium Synechocystis sp PCC 6803.

    PubMed

    Bottin, H; Lagoutte, B

    1992-07-06

    The unicellular cyanobacterium Synechocystis sp PCC 6803 is capable of synthesizing two different Photosystem-I electron acceptors, ferredoxin and flavodoxin. Under normal growth conditions a [2Fe-2S] ferredoxin was recovered and purified to homogeneity. The complete amino-acid sequence of this protein was established. The isoelectric point (pI = 3.48), midpoint redox potential (Em = -0.412 V) and stability under denaturing conditions were also determined. This ferredoxin exhibits an unusual electrophoretic behavior, resulting in a very low apparent molecular mass between 2 and 3.5 kDa, even in the presence of high concentrations of urea. However, a molecular mass of 10,232 Da (apo-ferredoxin) is calculated from the sequence. Free thiol assays indicate the presence of a disulfide bridge in this protein. A small amount of ferredoxin was also found in another fraction during the purification procedure. The amino-acid sequence and properties of this minor ferredoxin were similar to those of the major ferredoxin. However, its solubility in ammonium sulfate and its reactivity with antibodies directed against spinach ferredoxin were different. Traces of flavodoxin were also recovered from the same fraction. The amount of flavodoxin was dramatically increased under iron-deficient growth conditions. An acidic isoelectric point was measured (pI = 3.76), close to that of ferredoxin. The midpoint redox potentials of flavodoxin are Em1 = -0.433 V and Em2 = -0.238 V at pH 7.8. Sequence comparison based on the 42 N-terminal amino acids indicates that Synechocystis 6803 flavodoxin most likely belongs to the long-chain class, despite an apparent molecular mass of 15 kDa determined by SDS-PAGE.

  4. Impacts of diurnal variation of ultraviolet-B and photosynthetically active radiation on phycobiliproteins of the hot-spring cyanobacterium Nostoc sp. strain HKAR-2.

    PubMed

    Kannaujiya, Vinod K; Sinha, Rajeshwar P

    2017-01-01

    The effects of diurnal variation of photosynthetically active radiation (PAR; 400-700 nm) and ultraviolet-B (UV-B; 280-315 nm) radiation on phycobiliproteins (PBPs) and photosynthetic pigments (PP) have been studied in the hot-spring cyanobacterium Nostoc sp. strain HKAR-2. The variations in PBPs and PP were monitored by alternating light and dark under PAR, UV-B, and PAR + UV-B radiations over a period of 25 h. There was a decline in the amount of Chl a and PBPs during light periods of UV-B and PAR + UV-B and an increase during dark periods showing a circadian rhythm by destruction and resynthesis of pigment-protein complex. However, a marked induction in carotenoids was recorded during light periods of the same radiations. Moreover, the ratio of Chl a/PE and Chl a/PC was increased in dark periods showing the resynthesis of bleached Chl a. The wavelength shift in emission fluorescence of PBPs toward shorter wavelengths further indicated the bleaching and destruction of PBPs during light periods. Oxidative damage upon exposure to PAR, UV-B, and PAR + UV-B was alleviated by induction of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The studied cyanobacterium exhibits a significant increase in the activities of SOD, CAT, and APX upon exposure to UV-B and PAR + UV-B radiations. The results indicate that pigment-protein composition of Nostoc sp. stain HKAR-2 was significantly altered during diurnal variation of light/radiation, which might play an important role in optimization for their productivity in a particular cyanobacterium.

  5. Competition and facilitation between the marine nitrogen-fixing cyanobacterium Cyanothece and its associated bacterial community

    PubMed Central

    Brauer, Verena S.; Stomp, Maayke; Bouvier, Thierry; Fouilland, Eric; Leboulanger, Christophe; Confurius-Guns, Veronique; Weissing, Franz J.; Stal, LucasJ.; Huisman, Jef

    2014-01-01

    N2-fixing cyanobacteria represent a major source of new nitrogen and carbon for marine microbial communities, but little is known about their ecological interactions with associated microbiota. In this study we investigated the interactions between the unicellular N2-fixing cyanobacterium Cyanothece sp. Miami BG043511 and its associated free-living chemotrophic bacteria at different concentrations of nitrate and dissolved organic carbon and different temperatures. High temperature strongly stimulated the growth of Cyanothece, but had less effect on the growth and community composition of the chemotrophic bacteria. Conversely, nitrate and carbon addition did not significantly increase the abundance of Cyanothece, but strongly affected the abundance and species composition of the associated chemotrophic bacteria. In nitrate-free medium the associated bacterial community was co-dominated by the putative diazotroph Mesorhizobium and the putative aerobic anoxygenic phototroph Erythrobacter and after addition of organic carbon also by the Flavobacterium Muricauda. Addition of nitrate shifted the composition toward co-dominance by Erythrobacter and the Gammaproteobacterium Marinobacter. Our results indicate that Cyanothece modified the species composition of its associated bacteria through a combination of competition and facilitation. Furthermore, within the bacterial community, niche differentiation appeared to play an important role, contributing to the coexistence of a variety of different functional groups. An important implication of these findings is that changes in nitrogen and carbon availability due to, e.g., eutrophication and climate change are likely to have a major impact on the species composition of the bacterial community associated with N2-fixing cyanobacteria. PMID:25642224

  6. Phosphoproteome of the cyanobacterium Synechocystis sp. PCC 6803 and its dynamics during nitrogen starvation

    PubMed Central

    Spät, Philipp; Maček, Boris; Forchhammer, Karl

    2015-01-01

    Cyanobacteria have shaped the earth's biosphere as the first oxygenic photoautotrophs and still play an important role in many ecosystems. The ability to adapt to changing environmental conditions is an essential characteristic in order to ensure survival. To this end, numerous studies have shown that bacteria use protein post-translational modifications such as Ser/Thr/Tyr phosphorylation in cell signaling, adaptation, and regulation. Nevertheless, our knowledge of cyanobacterial phosphoproteomes and their dynamic response to environmental stimuli is relatively limited. In this study, we applied gel-free methods and high accuracy mass spectrometry toward the detection of Ser/Thr/Tyr phosphorylation events in the model cyanobacterium Synechocystis sp. PCC 6803. We could identify over 300 phosphorylation events in cultures grown on nitrate as exclusive nitrogen source. Chemical dimethylation labeling was applied to investigate proteome and phosphoproteome dynamics during nitrogen starvation. Our dataset describes the most comprehensive (phospho)proteome of Synechocystis to date, identifying 2382 proteins and 183 phosphorylation events and quantifying 2111 proteins and 148 phosphorylation events during nitrogen starvation. Global protein phosphorylation levels were increased in response to nitrogen depletion after 24 h. Among the proteins with increased phosphorylation, the PII signaling protein showed the highest fold-change, serving as positive control. Other proteins with increased phosphorylation levels comprised functions in photosynthesis and in carbon and nitrogen metabolism. This study reveals dynamics of Synechocystis phosphoproteome in response to environmental stimuli and suggests an important role of protein Ser/Thr/Tyr phosphorylation in fundamental mechanisms of homeostatic control in cyanobacteria. PMID:25873915

  7. Intercellular Diffusion of a Fluorescent Sucrose Analog via the Septal Junctions in a Filamentous Cyanobacterium

    PubMed Central

    Nürnberg, Dennis J.; Mariscal, Vicente; Bornikoel, Jan; Nieves-Morión, Mercedes; Krauß, Norbert; Herrero, Antonia

    2015-01-01

    ABSTRACT Many filamentous cyanobacteria produce specialized nitrogen-fixing cells called heterocysts, which are located at semiregular intervals along the filament with about 10 to 20 photosynthetic vegetative cells in between. Nitrogen fixation in these complex multicellular bacteria depends on metabolite exchange between the two cell types, with the heterocysts supplying combined-nitrogen compounds but dependent on the vegetative cells for photosynthetically produced carbon compounds. Here, we used a fluorescent tracer to probe intercellular metabolite exchange in the filamentous heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120. We show that esculin, a fluorescent sucrose analog, is incorporated by a sucrose import system into the cytoplasm of Anabaena cells. The cytoplasmic esculin is rapidly and reversibly exchanged across vegetative-vegetative and vegetative-heterocyst cell junctions. Our measurements reveal the kinetics of esculin exchange and also show that intercellular metabolic communication is lost in a significant fraction of older heterocysts. SepJ, FraC, and FraD are proteins located at the intercellular septa and are suggested to form structures analogous to gap junctions. We show that a ΔsepJ ΔfraC ΔfraD triple mutant shows an altered septum structure with thinner septa but a denser peptidoglycan layer. Intercellular diffusion of esculin and fluorescein derivatives is impaired in this mutant, which also shows a greatly reduced frequency of nanopores in the intercellular septal cross walls. These findings suggest that FraC, FraD, and SepJ are important for the formation of junctional structures that constitute the major pathway for feeding heterocysts with sucrose. PMID:25784700

  8. Evolving interactions between diazotrophic cyanobacterium and phage mediate nitrogen release and host competitive ability

    PubMed Central

    Coloma, Sebastián; Sivonen, Kaarina

    2016-01-01

    Interactions between nitrogen-fixing (i.e. diazotrophic) cyanobacteria and their viruses, cyanophages, can have large-scale ecosystem effects. These effects are mediated by temporal alterations in nutrient availability in aquatic systems owing to the release of nitrogen and carbon sources from cells lysed by phages, as well as by ecologically important changes in the diversity and fitness of cyanobacterial populations that evolve in the presence of phages. However, ecological and evolutionary feedbacks between phages and nitrogen-fixing cyanobacteria are still relative poorly understood. Here, we used an experimental evolution approach to test the effect of interactions between a common filamentous, nitrogen-fixing cyanobacterium (Nodularia sp.) and its phage on cellular nitrogen release and host properties. Ecological, community-level effects of phage-mediated nitrogen release were tested with a phytoplankton bioassay. We found that cyanobacterial nitrogen release increased significantly as a result of viral lysis, which was associated with enhanced growth of phytoplankton species in cell-free filtrates compared with phage-resistant host controls in which lysis and subsequent nutrient release did not occur after phage exposure. We also observed an ecologically important change among phage-evolved cyanobacteria with phage-resistant phenotypes, a short-filamentous morphotype with reduced buoyancy compared with the ancestral long-filamentous morphotype. Reduced buoyancy might decrease the ability of these morphotypes to compete for light compared with longer, more buoyant filaments. Together, these findings demonstrate the potential of cyanobacteria–phage interactions to affect ecosystem biogeochemical cycles and planktonic community dynamics. PMID:28083116

  9. A consensus linkage map for molecular markers and Quantitative Trait Loci associated with economically important traits in melon (Cucumis melo L.)

    PubMed Central

    2011-01-01

    Background A number of molecular marker linkage maps have been developed for melon (Cucumis melo L.) over the last two decades. However, these maps were constructed using different marker sets, thus, making comparative analysis among maps difficult. In order to solve this problem, a consensus genetic map in melon was constructed using primarily highly transferable anchor markers that have broad potential use for mapping, synteny, and comparative quantitative trait loci (QTL) analysis, increasing breeding effectiveness and efficiency via marker-assisted selection (MAS). Results Under the framework of the International Cucurbit Genomics Initiative (ICuGI, http://www.icugi.org), an integrated genetic map has been constructed by merging data from eight independent mapping experiments using a genetically diverse array of parental lines. The consensus map spans 1150 cM across the 12 melon linkage groups and is composed of 1592 markers (640 SSRs, 330 SNPs, 252 AFLPs, 239 RFLPs, 89 RAPDs, 15 IMAs, 16 indels and 11 morphological traits) with a mean marker density of 0.72 cM/marker. One hundred and ninety-six of these markers (157 SSRs, 32 SNPs, 6 indels and 1 RAPD) were newly developed, mapped or provided by industry representatives as released markers, including 27 SNPs and 5 indels from genes involved in the organic acid metabolism and transport, and 58 EST-SSRs. Additionally, 85 of 822 SSR markers contributed by Syngenta Seeds were included in the integrated map. In addition, 370 QTL controlling 62 traits from 18 previously reported mapping experiments using genetically diverse parental genotypes were also integrated into the consensus map. Some QTL associated with economically important traits detected in separate studies mapped to similar genomic positions. For example, independently identified QTL controlling fruit shape were mapped on similar genomic positions, suggesting that such QTL are possibly responsible for the phenotypic variability observed for this trait in

  10. Finished Genome Sequence of the Unicellular Cyanobacterium Synechocystis sp. Strain PCC 6714.

    PubMed

    Kopf, Matthias; Klähn, Stephan; Voss, Björn; Stüber, Kurt; Huettel, Bruno; Reinhardt, Richard; Hess, Wolfgang R

    2014-07-31

    Synechocystis sp. strain PCC 6714 is a unicellular cyanobacterium closely related to the popular model organism Synechocystis sp. strain PCC 6803. A combination of PacBio SMRT and Illumina GAIIx data results in a highly accurate finished genome sequence that provides a reliable resource for further comparative analyses.

  11. Genome Sequence of the Thermophilic Cyanobacterium Thermosynechococcus sp. Strain NK55a.

    SciTech Connect

    Stolyar, Sergey; Liu, Zhenfeng; Thiel, Vera; Tomsho, Lynn P.; Pinel, Nicolas; Nelson, William C.; Lindemann, Stephen R.; Romine, Margaret F.; Haruta, Shin; Schuster, Stephan C.; Bryant, Donald A.; Fredrickson, Jim K.

    2014-01-02

    The genome of the unicellular cyanobacterium, Thermosynechococcus sp. strain NK55a, isolated from Nakabusa hot spring, comprises a single, circular, 2.5-Mb chromosome. The genome is predicted to encode 2358 protein coding genes, including genes for all typical cyanobacterial photosynthetic and metabolic functions. No genes encoding hydrogenases or nitrogenase were identified.

  12. Lyngbyabellin B, a toxic and antifungal secondary metabolite from the marine cyanobacterium Lyngbya majuscula.

    PubMed

    Milligan, K E; Marquez, B L; Williamson, R T; Gerwick, W H

    2000-10-01

    Lyngbyabellin B (1) was isolated from a marine cyanobacterium, Lyngbya majuscula, collected near the Dry Tortugas National Park, Florida. This new cyclic depsipeptide displayed potent toxicity toward brine shrimp and the fungus Candida albicans. The planar structure was deduced using 1D and 2D NMR spectroscopic methods, and the stereochemistry is proposed through a combination of NMR and chiral GC/MS analysis.

  13. Draft Genome Sequence of Cyanobacterium sp. Strain IPPAS B-1200 with a Unique Fatty Acid Composition

    PubMed Central

    Starikov, Alexander Y.; Usserbaeva, Aizhan A.; Sinetova, Maria A.; Sarsekeyeva, Fariza K.; Zayadan, Bolatkhan K.; Ustinova, Vera V.; Kupriyanova, Elena V.; Los, Dmitry A.

    2016-01-01

    Here, we report the draft genome of Cyanobacterium sp. IPPAS strain B-1200, isolated from Lake Balkhash, Kazakhstan, and characterized by the unique fatty acid composition of its membrane lipids, which are enriched with myristic and myristoleic acids. The approximate genome size is 3.4 Mb, and the predicted number of coding sequences is 3,119. PMID:27856596

  14. Complete Genome Sequence of a Coastal Cyanobacterium, Synechococcus sp. Strain NIES-970

    PubMed Central

    Hirose, Yuu; Misawa, Naomi; Wakazuki, Sachiko; Fujisawa, Takatomo; Nakamura, Yasukazu; Kanesaki, Yu; Yamaguchi, Haruyo; Kawachi, Masanobu

    2017-01-01

    ABSTRACT Members of the cyanobacterial genus Synechococcus are abundant in marine environments. To better understand the genomic diversity of marine Synechococcus spp., we determined the complete genome sequence of a coastal cyanobacterium, Synechococcus sp. NIES-970. The genome had a size of 3.1 Mb, consisting of one chromosome and four plasmids. PMID:28385852

  15. Draft Genome Assembly of a Filamentous Euendolithic (True Boring) Cyanobacterium, Mastigocoleus testarum Strain BC008.

    PubMed

    Guida, Brandon S; Garcia-Pichel, Ferran

    2016-01-28

    Mastigocoleus testarum strain BC008 is a model organism used to study marine photoautotrophic carbonate dissolution. It is a multicellular, filamentous, diazotrophic, euendolithic cyanobacterium ubiquitously found in marine benthic environments. We present an accurate draft genome assembly of 172 contigs spanning 12,700,239 bp with 9,131 annotated genes with an average G+C% of 37.3.

  16. Temporal Variability in Nitrogenase Gene Expression in Natural Populations of the Marine Cyanobacterium Trichodesmium thiebautii

    PubMed Central

    Wyman, M.; Zehr, J. P.; Capone, D. G.

    1996-01-01

    We report a distinct diel periodicity in the abundance of nifH (dinitrogenase reductase) mRNA in natural populations of the nonheterocystous marine cyanobacterium Trichodesmium thiebautii. Our observations show that in addition to translational and posttranslational controls, Trichodesmium nitrogenase expression is also regulated at the transcriptional and/or posttranscriptional level. PMID:16535258

  17. Note to Budget Cutters: The Arts Are Good Business--Multiple Studies Point to Arts Education as an Important Economic Engine

    ERIC Educational Resources Information Center

    Olson, Catherine Applefeld

    2009-01-01

    They say desperate times call for desperate measures. But in this time of economic uncertainty, the desperate cutting of budgets for arts funding and, by extension, all types of arts education, including music, is not prudent. That is the consensus of several national and local studies, which converge on a single point--that the arts actually can…

  18. Education for Global Leadership: The Importance of International Studies and Foreign Language Education for U.S. Economic and National Security. Executive Summary

    ERIC Educational Resources Information Center

    Committee for Economic Development, 2006

    2006-01-01

    As we begin the twenty-first century, technological, economic, political, and social forces have created a new era. Technological advancements and lower trade barriers have paved the way for the globalization of markets, bringing intense competition to the U.S. economy. Political systems and movements around the world are having a profound impact…

  19. Ecological economics and economic growth.

    PubMed

    Victor, Peter A

    2010-01-01

    Boulding's 1966 paper on the economics of spaceship Earth established the framework for ecological economics and an understanding of economic growth. In ecological economics, economies are conceptualized as open subsystems of the closed biosphere and are subject to biophysical laws and constraints. Economic growth measured as an increase in real gross domestic product (GDP) has generally been associated with increases in the use of energy and materials and the generation of wastes. Scale, composition, and technology are the proximate determinants of environmental impacts. They are often reduced to two: scale (GDP) and intensity (impact per unit GDP). New work described in this paper defines "green" growth as intensity that declines faster than scale increases. Similarly, "brown" growth occurs when intensity declines more slowly than increases in scale, and "black" growth happens when both scale and intensity increase. These concepts are then related to the environmental Kuznets curve, which can be understood as a transition from brown to green growth. Ecological economics provides a macroperspective on economic growth. It offers broad policy principles, and it challenges the primacy of economic growth as a policy objective, but many important questions remain.

  20. Structural insight into photoactivation of an adenylate cyclase from a photosynthetic cyanobacterium

    PubMed Central

    Ohki, Mio; Sugiyama, Kanako; Kawai, Fumihiro; Tanaka, Hitomi; Nihei, Yuuki; Unzai, Satoru; Takebe, Masumi; Matsunaga, Shigeru; Adachi, Shin-ichi; Shibayama, Naoya; Zhou, Zhiwen; Koyama, Ryuta; Takahashi, Tetsuo; Tame, Jeremy R. H.; Iseki, Mineo; Park, Sam-Yong

    2016-01-01

    Cyclic-AMP is one of the most important second messengers, regulating many crucial cellular events in both prokaryotes and eukaryotes, and precise spatial and temporal control of cAMP levels by light shows great promise as a simple means of manipulating and studying numerous cell pathways and processes. The photoactivated adenylate cyclase (PAC) from the photosynthetic cyanobacterium Oscillatoria acuminata (OaPAC) is a small homodimer eminently suitable for this task, requiring only a simple flavin chromophore within a blue light using flavin (BLUF) domain. These domains, one of the most studied types of biological photoreceptor, respond to blue light and either regulate the activity of an attached enzyme domain or change its affinity for a repressor protein. BLUF domains were discovered through studies of photo-induced movements of Euglena gracilis, a unicellular flagellate, and gene expression in the purple bacterium Rhodobacter sphaeroides, but the precise details of light activation remain unknown. Here, we describe crystal structures and the light regulation mechanism of the previously undescribed OaPAC, showing a central coiled coil transmits changes from the light-sensing domains to the active sites with minimal structural rearrangement. Site-directed mutants show residues essential for signal transduction over 45 Å across the protein. The use of the protein in living human cells is demonstrated with cAMP-dependent luciferase, showing a rapid and stable response to light over many hours and activation cycles. The structures determined in this study will assist future efforts to create artificial light-regulated control modules as part of a general optogenetic toolkit. PMID:27247413

  1. Short RNA half-lives in the slow-growing marine cyanobacterium Prochlorococcus

    PubMed Central

    2010-01-01

    Background RNA turnover plays an important role in the gene regulation of microorganisms and influences their speed of acclimation to environmental changes. We investigated whole-genome RNA stability of Prochlorococcus, a relatively slow-growing marine cyanobacterium doubling approximately once a day, which is extremely abundant in the oceans. Results Using a combination of microarrays, quantitative RT-PCR and a new fitting method for determining RNA decay rates, we found a median half-life of 2.4 minutes and a median decay rate of 2.6 minutes for expressed genes - twofold faster than that reported for any organism. The shortest transcript half-life (33 seconds) was for a gene of unknown function, while some of the longest (approximately 18 minutes) were for genes with high transcript levels. Genes organized in operons displayed intriguing mRNA decay patterns, such as increased stability, and delayed onset of decay with greater distance from the transcriptional start site. The same phenomenon was observed on a single probe resolution for genes greater than 2 kb. Conclusions We hypothesize that the fast turnover relative to the slow generation time in Prochlorococcus may enable a swift response to environmental changes through rapid recycling of nucleotides, which could be advantageous in nutrient poor oceans. Our growing understanding of RNA half-lives will help us interpret the growing bank of metatranscriptomic studies of wild populations of Prochlorococcus. The surprisingly complex decay patterns of large transcripts reported here, and the method developed to describe them, will open new avenues for the investigation and understanding of RNA decay for all organisms. PMID:20482874

  2. Dependence of the Cyanobacterium Prochlorococcus on Hydrogen Peroxide Scavenging Microbes for Growth at the Ocean's Surface

    PubMed Central

    Morris, J. Jeffrey; Johnson, Zackary I.; Szul, Martin J.; Keller, Martin; Zinser, Erik R.

    2011-01-01

    The phytoplankton community in the oligotrophic open ocean is numerically dominated by the cyanobacterium Prochlorococcus, accounting for approximately half of all photosynthesis. In the illuminated euphotic zone where Prochlorococcus grows, reactive oxygen species are continuously generated via photochemical reactions with dissolved organic matter. However, Prochlorococcus genomes lack catalase and additional protective mechanisms common in other aerobes, and this genus is highly susceptible to oxidative damage from hydrogen peroxide (HOOH). In this study we showed that the extant microbial community plays a vital, previously unrecognized role in cross-protecting Prochlorococcus from oxidative damage in the surface mixed layer of the oligotrophic ocean. Microbes are the primary HOOH sink in marine systems, and in the absence of the microbial community, surface waters in the Atlantic and Pacific Ocean accumulated HOOH to concentrations that were lethal for Prochlorococcus cultures. In laboratory experiments with the marine heterotroph Alteromonas sp., serving as a proxy for the natural community of HOOH-degrading microbes, bacterial depletion of HOOH from the extracellular milieu prevented oxidative damage to the cell envelope and photosystems of co-cultured Prochlorococcus, and facilitated the growth of Prochlorococcus at ecologically-relevant cell concentrations. Curiously, the more recently evolved lineages of Prochlorococcus that exploit the surface mixed layer niche were also the most sensitive to HOOH. The genomic streamlining of these evolved lineages during adaptation to the high-light exposed upper euphotic zone thus appears to be coincident with an acquired dependency on the extant HOOH-consuming community. These results underscore the importance of (indirect) biotic interactions in establishing niche boundaries, and highlight the impacts that community-level responses to stress may have in the ecological and evolutionary outcomes for co-existing species

  3. Low temperature delays timing and enhances the cost of nitrogen fixation in the unicellular cyanobacterium Cyanothece

    PubMed Central

    Brauer, Verena S; Stomp, Maayke; Rosso, Camillo; van Beusekom, Sebastiaan AM; Emmerich, Barbara; Stal, Lucas J; Huisman, Jef

    2013-01-01

    Marine nitrogen-fixing cyanobacteria are largely confined to the tropical and subtropical ocean. It has been argued that their global biogeographical distribution reflects the physiologically feasible temperature range at which they can perform nitrogen fixation. In this study we refine this line of argumentation for the globally important group of unicellular diazotrophic cyanobacteria, and pose the following two hypotheses: (i) nitrogen fixation is limited by nitrogenase activity at low temperature and by oxygen diffusion at high temperature, which is manifested by a shift from strong to weak temperature dependence of nitrogenase activity, and (ii) high respiration rates are required to maintain very low levels of oxygen for nitrogenase, which results in enhanced respiratory cost per molecule of fixed nitrogen at low temperature. We tested these hypotheses in laboratory experiments with the unicellular cyanobacterium Cyanothece sp. BG043511. In line with the first hypothesis, the specific growth rate increased strongly with temperature from 18 to 30 °C, but leveled off at higher temperature under nitrogen-fixing conditions. As predicted by the second hypothesis, the respiratory cost of nitrogen fixation and also the cellular C:N ratio rose sharply at temperatures below 21 °C. In addition, we found that low temperature caused a strong delay in the onset of the nocturnal nitrogenase activity, which shortened the remaining nighttime available for nitrogen fixation. Together, these results point at a lower temperature limit for unicellular nitrogen-fixing cyanobacteria, which offers an explanation for their (sub)tropical distribution and suggests expansion of their biogeographical range by global warming. PMID:23823493

  4. Structural investigation of the antagonist LPS from the cyanobacterium Oscillatoria planktothrix FP1.

    PubMed

    Carillo, Sara; Pieretti, Giuseppina; Bedini, Emiliano; Parrilli, Michelangelo; Lanzetta, Rosa; Corsaro, Maria Michela

    2014-03-31

    Cyanobacteria are aquatic and photosynthetic microorganisms, which contribute up to 30% of the yearly oxygen production on the earth. They have the distinction of being the oldest known fossils, more than 3.5 billion years old, and are one of the largest and most important groups of bacteria on earth. Cyanobacteria are an emerging source of potentially pharmacologically active products and, among these, there are the lipopolysaccharides. Despite their significant and well documented activity, very little is known about the cyanobacteria lipopolysaccharides (LPS) structure. The aim of this work is to investigate the structure of the highly TLR4-antagonist lipopolysaccharide from the cyanobacterium Oscillatoria plankthotrix FP1. The LPS was purified and analysed by means of chemical analysis and 1H and 13C NMR spectroscopy. The LPS was then degraded by Smith degradation, HF and acetic acid hydrolyses. All the obtained products were investigated in detail by chemical analysis, NMR spectroscopy and by mass spectrometry. The LPS consists of a high molecular mass and very complex molecule lacking Kdo and heptose residues, where the polysaccharide chain is mainly constituted by a backbone of 3-substituted α-l-rhamnose units. The core region is rich in galacturonic acid and mannose residues. Moreover a glycolipid portion, similar to Gram-negative lipid A, was identified. This was built up of a non phosphorylated (1'→6) linked glucosamine disaccharide, acylated with 3-hydroxylated fatty acids. In particular 3-hydroxypentadecanoic and 3-hydroxyesadecanoic acids were found, together with esadecanoic and tetradecanoic ones. Finally the presence of a galacturonic acid residue at 6-position of the distal glucosamine in place of the Kdo residue is suggested. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Arsenic Sensing and Resistance System in the Cyanobacterium Synechocystis sp. Strain PCC 6803

    PubMed Central

    López-Maury, Luis; Florencio, Francisco J.; Reyes, José C.

    2003-01-01

    Arsenic is one of the most important global environmental pollutants. Here we show that the cyanobacterium Synechocystis sp. strain PCC 6803 contains an arsenic and antimony resistance operon consisting of three genes: arsB, encoding a putative arsenite and antimonite carrier, arsH, encoding a protein of unknown function, and arsC, encoding a putative arsenate reductase. While arsB mutant strains were sensitive to arsenite, arsenate, and antimonite, arsC mutants were sensitive only to arsenate. The arsH mutant strain showed no obvious phenotype under the conditions tested. In vivo the arsBHC operon was derepressed by oxyanions of arsenic and antimony (oxidation state, +3) and, to a lesser extent, by bismuth (oxidation state, +3) and arsenate (oxidation state, +5). In the absence of these effectors, the operon was repressed by a transcription repressor of the ArsR/SmtB family, encoded by an unlinked gene termed arsR. Thus, arsR null mutants showed constitutive derepression of the arsBHC operon. Expression of the arsR gene was not altered by the presence of arsenic or antimony compounds. Purified recombinant ArsR protein binds to the arsBHC promoter-operator region in the absence of metals and dissociates from the DNA in the presence of Sb(III) or As(III) but not in the presence of As(V), suggesting that trivalent metalloids are the true inducers of the system. DNase I footprinting experiments indicate that ArsR binds to two 17-bp direct repeats, with each one consisting of two inverted repeats, in the region from nucleotides −34 to + 17 of the arsBHC promoter-operator. PMID:12949088

  6. Low temperature delays timing and enhances the cost of nitrogen fixation in the unicellular cyanobacterium Cyanothece.

    PubMed

    Brauer, Verena S; Stomp, Maayke; Rosso, Camillo; van Beusekom, Sebastiaan A M; Emmerich, Barbara; Stal, Lucas J; Huisman, Jef

    2013-11-01

    Marine nitrogen-fixing cyanobacteria are largely confined to the tropical and subtropical ocean. It has been argued that their global biogeographical distribution reflects the physiologically feasible temperature range at which they can perform nitrogen fixation. In this study we refine this line of argumentation for the globally important group of unicellular diazotrophic cyanobacteria, and pose the following two hypotheses: (i) nitrogen fixation is limited by nitrogenase activity at low temperature and by oxygen diffusion at high temperature, which is manifested by a shift from strong to weak temperature dependence of nitrogenase activity, and (ii) high respiration rates are required to maintain very low levels of oxygen for nitrogenase, which results in enhanced respiratory cost per molecule of fixed nitrogen at low temperature. We tested these hypotheses in laboratory experiments with the unicellular cyanobacterium Cyanothece sp. BG043511. In line with the first hypothesis, the specific growth rate increased strongly with temperature from 18 to 30 °C, but leveled off at higher temperature under nitrogen-fixing conditions. As predicted by the second hypothesis, the respiratory cost of nitrogen fixation and also the cellular C:N ratio rose sharply at temperatures below 21 °C. In addition, we found that low temperature caused a strong delay in the onset of the nocturnal nitrogenase activity, which shortened the remaining nighttime available for nitrogen fixation. Together, these results point at a lower temperature limit for unicellular nitrogen-fixing cyanobacteria, which offers an explanation for their (sub)tropical distribution and suggests expansion of their biogeographical range by global warming.

  7. Multiplicity and specificity of siderophore uptake in the cyanobacterium Anabaena sp. PCC 7120.

    PubMed

    Rudolf, Mareike; Stevanovic, Mara; Kranzler, Chana; Pernil, Rafael; Keren, Nir; Schleiff, Enrico

    2016-09-01

    Many cyanobacteria secrete siderophores to sequester iron. Alternatively, mechanisms to utilize xenosiderophores have evolved. The overall uptake systems are comparable to that of other bacteria involving outer membrane transporters energized by TonB as well as plasma membrane-localized transporters. However, the function of the bioinformatically-inferred components is largely not established and recent studies showed a high diversity of the complexity of the uptake systems in different cyanobacteria. Thus, we approached the systems of the filamentous Anabaena sp. PCC 7120 as a model of a siderophore-secreting cyanobacterium. Anabaena sp. produces schizokinen and uptake of Fe-schizokinen involves the TonB-dependent transporter, schizokinen transporter (SchT), and the ABC-type transport system FhuBCD. We confirm that this system is also relevant for the uptake of structurally similar Fe-siderophore complexes like Fe-aerobactin. Moreover, we demonstrate a function of the TonB-dependent transporter IutA2 in Fe-schizokinen uptake in addition to SchT. The iutA2 mutant shows growth defects upon iron limitation, alterations in Fe-schizokinen uptake and in the transcription profile of the Fe-schizokinen uptake system. The physiological properties of the mutant confirm the importance of iron uptake for cellular function, e.g. for the Krebs cycle. Based on the relative relation of expression of schT and iutA2 as well as of the iron uptake rate to the degree of starvation, a model for the need of the co-existence of two different outer membrane transporters for the same substrate is discussed.

  8. Physiological and biochemical effects of allelochemical ethyl 2-methyl acetoacetate (EMA) on cyanobacterium Microcystis aeruginosa.

    PubMed

    Hong, Yu; Hu, Hong-Ying; Li, Feng-Min

    2008-10-01

    The physiological and biochemical effects of an allelochemical ethyl 2-methyl acetoacetate (EMA) isolated from reed (Phragmites communis) on bloom-forming cyanobacterium, Microcystis aeruginosa, were investigated. EMA significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The metabolic indices (represented by esterase and total dehydrogenase activities), the cellular redox status (represented by the level of reactive oxygen species (ROS)), and the oxidative damage index (represented by the content of malondialdehyde (MDA), the product of membrane lipid peroxidation) were used to evaluate the physiological and biochemical changes in M. aeruginosa after EMA exposure. Esterase activity in M. aeruginosa did not change (P>0.05) after 2 h of exposure to EMA, but increased greatly after 24 and 48 h (P<0.05). EMA exposure (>0.5 mg L(-1)) resulted in a remarkable loss of total dehydrogenase activity in M. aeruginosa after 4 h (P<0.01), but an increase after 40 h (P<0.05). EMA caused a great increase in ROS level of the algal cells. At high EMA concentration (4 mg L(-1)), the ROS level was remarkably elevated to 1.91 times as much as that in the controls after 2 h. Increases in the ROS level also occurred after 24 and 48 h. The increase in lipid peroxidation of M. aeruginosa was dependent upon EMA concentration and the exposure time. After 40 h of exposure, the MDA content at 4 mg L(-1) of EMA reached approximately 3.5 times (P<0.01) versus the controls. These results suggest that the cellular structure and metabolic activity of M. aeruginosa are influenced by EMA; the increased metabolic activity perhaps reflects the fact that the resistance of cellular response system to the stress from EMA is initiated during EMA exposure, and the oxidative damage induced by EMA via the oxidation of ROS may be an important factor responsible for the inhibition of EMA on the growth of M. aeruginosa.

  9. Sustained H2 Production Driven by Photosynthetic Water Splitting in a Unicellular Cyanobacterium

    PubMed Central

    Melnicki, Matthew R.; Pinchuk, Grigoriy E.; Hill, Eric A.; Kucek, Leo A.; Fredrickson, Jim K.; Konopka, Allan; Beliaev, Alexander S.

    2012-01-01

    ABSTRACT The relationship between dinitrogenase-driven H2 production and oxygenic photosynthesis was investigated in a unicellular cyanobacterium, Cyanothece sp. ATCC 51142, using a novel custom-built photobioreactor equipped with advanced process control. Continuously illuminated nitrogen-deprived cells evolved H2 at rates up to 400 µmol ⋅ mg Chl−1 ⋅ h−1 in parallel with uninterrupted photosynthetic O2 production. Notably, sustained coproduction of H2 and O2 occurred over 100 h in the presence of CO2, with both gases displaying inverse oscillations which eventually dampened toward stable rates of 125 and 90 µmol ⋅ mg Chl−1 ⋅ h−1, respectively. Oscillations were not observed when CO2 was omitted, and instead H2 and O2 evolution rates were positively correlated. The sustainability of the process was further supported by stable chlorophyll content, maintenance of baseline protein and carbohydrate levels, and an enhanced capacity for linear electron transport as measured by chlorophyll fluorescence throughout the experiment. In situ light saturation analyses of H2 production displayed a strong dose dependence and lack of O2 inhibition. Inactivation of photosystem II had substantial long-term effects but did not affect short-term H2 production, indicating that the process is also supported by photosystem I activity and oxidation of endogenous glycogen. However, mass balance calculations suggest that carbohydrate consumption in the light may, at best, account for no more than 50% of the reductant required for the corresponding H2 production over that period. Collectively, our results demonstrate that uninterrupted H2 production in unicellular cyanobacteria can be fueled by water photolysis without the detrimental effects of O2 and have important implications for sustainable production of biofuels. PMID:22872781

  10. Arsenic Demethylation by a C·As Lyase in Cyanobacterium Nostoc sp. PCC 7120.

    PubMed

    Yan, Yu; Ye, Jun; Xue, Xi-Mei; Zhu, Yong-Guan

    2015-12-15

    Arsenic, a ubiquitous toxic substance, exists mainly as inorganic forms in the environment. It is perceived that organoarsenicals can be demethylated and degraded into inorganic arsenic by microorganisms. Few studies have focused on the mechanism of arsenic demethylation in bacteria. Here, we investigated arsenic demethylation in a typical freshwater cyanobacterium Nostoc sp. PCC 7120. This bacterium was able to demethylate monomethylarsenite [MAs(III)] rapidly to arsenite [As(III)] and also had the ability to demethylate monomethylarsenate [MAs(V)] to As(III). The NsarsI encoding a C·As lyase responsible for MAs(III) demethylation was cloned from Nostoc sp. PCC 7120 and heterologously expressed in an As-hypersensitive strain Escherichia coli AW3110 (ΔarsRBC). Expression of NsarsI was shown to confer MAs(III) resistance through arsenic demethylation. The purified NsArsI was further identified and functionally characterized in vitro. NsArsI existed mainly as the trimeric state, and the kinetic data were well-fit to the Hill equation with K0.5 = 7.55 ± 0.33 μM for MAs(III), Vmax = 0.79 ± 0.02 μM min(-1), and h = 2.7. Both of the NsArsI truncated derivatives lacking the C-terminal 10 residues (ArsI10) or 23 residues (ArsI23) had a reduced ability of MAs(III) demethylation. These results provide new insights for understanding the important role of cyanobacteria in arsenic biogeochemical cycling in the environment.

  11. ESEA Reauthorization: The Importance of a World-Class K-12 Education for Our Economic Success. Hearing of the Committee on Health, Education, Labor, and Pensions, United States Senate, One Hundred Eleventh Congress, Second Session on Examining Elementary and Secondary Education Act (ESEA) Reauthorization, Focusing on K-12 Education for Economic Success (March 9, 2010). Senate Hearing 111-885

    ERIC Educational Resources Information Center

    US Senate, 2011

    2011-01-01

    This hearing of the Committee of Health, Education, Labor and Pensions focused on the reauthorization of the Elementary and Secondary Education Act. This hearing on the economic importance of having a world-class K-12 education system should remind everyone of the critical importance of this reauthorization. Well-educated Americans are the single…

  12. Evolution of Anabaenopeptin Peptide Structural Variability in the Cyanobacterium Planktothrix

    PubMed Central

    Entfellner, Elisabeth; Frei, Mark; Christiansen, Guntram; Deng, Li; Blom, Jochen; Kurmayer, Rainer

    2017-01-01

    Cyanobacteria are frequently involved in the formation of harmful algal blooms wherein, apart from the toxic microcystins, other groups of bioactive peptides are abundant as well, such as anabaenopeptins (APs). The APs are synthesized nonribosomally as cyclic hexapeptides with various amino acids at the exocyclic position. We investigated the presence and recombination of the AP synthesis gene cluster (apnA-E) through comparing 125 strains of the bloom-forming cyanobacterium Planktothrix spp., which were isolated from numerous shallow and deep water habitats in the temperate and tropical climatic zone. Ten ecologically divergent strains were purified and genome sequenced to compare their entire apnA-E gene cluster. In order to quantify apn gene distribution patterns, all the strains were investigated by PCR amplification of 2 kbp portions of the entire apn gene cluster without interruption. Within the 11 strains assigned to P. pseudagardhii, P. mougeotii, or P. tepida (Lineage 3), neither apnA-E genes nor remnants were observed. Within the P. agardhii/P. rubescens strains from shallow waters (Lineage 1, 52 strains), strains both carrying and lacking apn genes occurred, while among the strains lacking the apnA-E genes, the presence of the 5′end flanking region indicated a gene cluster deletion. Among the strains of the more derived deep water ecotype (Lineage 2, 62 strains), apnA-E genes were always present. A high similarity of apn genes of the genus Planktothrix when compared with strains of the genus Microcystis suggested its horizontal gene transfer during the speciation of P. agardhii/P. rubescens. Genetic analysis of the first (A1-) domain of the apnA gene, encoding synthesis of the exocyclic position of the AP molecule, revealed four genotype groups that corresponded with substrate activation. Groups of genotypes were either related to Arginine only, the coproduction of Arginine and Tyrosine or Arginine and Lysine, or even the coproduction of Arginine

  13. The importance of economic, social and cultural capital in understanding health inequalities: using a Bourdieu-based approach in research on physical and mental health perceptions.

    PubMed

    Pinxten, Wouter; Lievens, John

    2014-09-01

    In this article we adopt a Bourdieu-based approach to study social inequalities in perceptions of mental and physical health. Most research takes into account the impact of economic or social capital on health inequalities. Bourdieu, however, distinguishes between three forms of capital that can determine peoples' social position: economic, social and cultural capital. Health research examining the effects of cultural capital is scarce. By simultaneously considering and modelling indicators of each of Bourdieu's forms of capital, we further the understanding of the dynamics of health inequalities. Using data from a large-scale representative survey (N = 1825) in Flanders, Belgium, we find that each of the forms of capital has a net effect on perceptions of physical and mental health, which persists after controlling for the other forms of capital and for the effects of other correlates of perceived health. The only exception is that the cultural capital indicators are not related to mental health. These results confirm the value of a Bourdieu-based approach and indicate the need to consider economic, social and cultural capital to obtain a better understanding of social inequality in health.

  14. Dried Colony in Cyanobacterium, Nostoc sp. HK-01 — Several high Space Environment Tolerances for ``Tanpopo'' Mission

    NASA Astrophysics Data System (ADS)

    Tomita-Yokotani, K.; Kimura, S.; Kimura, Y.; Igarashi, Y.; Ajioka, R.; Sato, S.; Katoh, H.; Baba, K.

    2013-11-01

    A cyanobacterium, Nostoc sp. HK-01, has high several space environmental tolerance. Nostoc sp HK-01 would have high contribution for the “Tanpopo” mission in Japan Experimental Module of the International Space Station.

  15. Intercellular diffusion of a fluorescent sucrose analog via the septal junctions in a filamentous cyanobacterium.

    PubMed

    Nürnberg, Dennis J; Mariscal, Vicente; Bornikoel, Jan; Nieves-Morión, Mercedes; Krauß, Norbert; Herrero, Antonia; Maldener, Iris; Flores, Enrique; Mullineaux, Conrad W

    2015-03-17

    Many filamentous cyanobacteria produce specialized nitrogen-fixing cells called heterocysts, which are located at semiregular intervals along the filament with about 10 to 20 photosynthetic vegetative cells in between. Nitrogen fixation in these complex multicellular bacteria depends on metabolite exchange between the two cell types, with the heterocysts supplying combined-nitrogen compounds but dependent on the vegetative cells for photosynthetically produced carbon compounds. Here, we used a fluorescent tracer to probe intercellular metabolite exchange in the filamentous heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120. We show that esculin, a fluorescent sucrose analog, is incorporated by a sucrose import system into the cytoplasm of Anabaena cells. The cytoplasmic esculin is rapidly and reversibly exchanged across vegetative-vegetative and vegetative-heterocyst cell junctions. Our measurements reveal the kinetics of esculin exchange and also show that intercellular metabolic communication is lost in a significant fraction of older heterocysts. SepJ, FraC, and FraD are proteins located at the intercellular septa and are suggested to form structures analogous to gap junctions. We show that a ΔsepJ ΔfraC ΔfraD triple mutant shows an altered septum structure with thinner septa but a denser peptidoglycan layer. Intercellular diffusion of esculin and fluorescein derivatives is impaired in this mutant, which also shows a greatly reduced frequency of nanopores in the intercellular septal cross walls. These findings suggest that FraC, FraD, and SepJ are important for the formation of junctional structures that constitute the major pathway for feeding heterocysts with sucrose. Anabaena and its relatives are filamentous cyanobacteria that exhibit a sophisticated form of prokaryotic multicellularity, with the formation of differentiated cell types, including normal photosynthetic cells and specialized nitrogen-fixing cells called heterocysts. The question

  16. Draft Genome Sequence of the Axenic Strain Phormidesmis priestleyi ULC007, a Cyanobacterium Isolated from Lake Bruehwiler (Larsemann Hills, Antarctica)

    PubMed Central

    Durieu, Benoit; Cornet, Luc; Verlaine, Olivier; Rippka, Rosmarie; Pessi, Igor S.; Misztak, Agnieszka; Joris, Bernard; Javaux, Emmanuelle J.; Baurain, Denis

    2017-01-01

    ABSTRACT Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacterium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein-encoding genes, of which 22.2% have no clear homologues in known genomes. To date, this draft genome is the first one ever determined for an axenic cyanobacterium from Antarctica. PMID:28209814

  17. Information for Importers of Hazardous Waste from Canada, Chile, Mexico or Non-Organization of Economic Cooperation and Development (OECD) Countries

    EPA Pesticide Factsheets

    Information for importers of hazardous waste from Canada, Chile, Mexico, or non-OECD countries who are subject to the hazardous waste generator and importer requirements described in 40 CFR Part 262 Subpart A – D and F, under RCRA

  18. Characterization of Function of the GlgA2 Glycogen/Starch Synthase in Cyanobacterium sp. Clg1 Highlights Convergent Evolution of Glycogen Metabolism into Starch Granule Aggregation.

    PubMed

    Kadouche, Derifa; Ducatez, Mathieu; Cenci, Ugo; Tirtiaux, Catherine; Suzuki, Eiji; Nakamura, Yasunori; Putaux, Jean-Luc; Terrasson, Amandine Durand; Diaz-Troya, Sandra; Florencio, Francisco Javier; Arias, Maria Cecilia; Striebeck, Alexander; Palcic, Monica; Ball, Steven G; Colleoni, Christophe

    2016-07-01

    At variance with the starch-accumulating plants and most of the glycogen-accumulating cyanobacteria, Cyanobacterium sp. CLg1 synthesizes both glycogen and starch. We now report the selection of a starchless mutant of this cyanobacterium that retains wild-type amounts of glycogen. Unlike other mutants of this type found in plants and cyanobacteria, this mutant proved to be selectively defective for one of the two types of glycogen/starch synthase: GlgA2. This enzyme is phylogenetically related to the previously reported SSIII/SSIV starch synthase that is thought to be involved in starch granule seeding in plants. This suggests that, in addition to the selective polysaccharide debranching demonstrated to be responsible for starch rather than glycogen synthesis, the nature and properties of the elongation enzyme define a novel determinant of starch versus glycogen accumulation. We show that the phylogenies of GlgA2 and of 16S ribosomal RNA display significant congruence. This suggests that this enzyme evolved together with cyanobacteria when they diversified over 2 billion years ago. However, cyanobacteria can be ruled out as direct progenitors of the SSIII/SSIV ancestral gene found in Archaeplastida. Hence, both cyanobacteria and plants recruited similar enzymes independently to perform analogous tasks, further emphasizing the importance of convergent evolution in the appearance of starch from a preexisting glycogen metabolism network.

  19. Changes in primary metabolism under light and dark conditions in response to overproduction of a response regulator RpaA in the unicellular cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Iijima, Hiroko; Shirai, Tomokazu; Okamoto, Mami; Kondo, Akihiko; Hirai, Masami Yokota; Osanai, Takashi

    2015-01-01

    The study of the primary metabolism of cyanobacteria in response to light conditions is important for environmental biology because cyanobacteria are widely distributed among various ecological niches. Cyanobacteria uniquely possess circadian rhythms, with central oscillators consisting from three proteins, KaiA, KaiB, and KaiC. The two-component histidine kinase SasA/Hik8 and response regulator RpaA transduce the circadian signal from KaiABC to control gene expression. Here, we generated a strain overexpressing rpaA in a unicellular cyanobacterium Synechocystis sp. PCC 6803. The rpaA-overexpressing strain showed pleiotropic phenotypes, including slower growth, aberrant degradation of an RNA polymerase sigma factor SigE after the light-to-dark transition, and higher accumulation of sugar catabolic enzyme transcripts under dark conditions. Metabolome analysis revealed delayed glycogen degradation, decreased sugar phosphates and organic acids in the tricarboxylic acid cycle, and increased amino acids under dark conditions. The current results demonstrate that in this cyanobacterium, RpaA is a regulator of primary metabolism and involved in adaptation to changes in light conditions.

  20. A high constitutive catalase activity confers resistance to methyl viologen-promoted oxidative stress in a mutant of the cyanobacterium Nostoc punctiforme ATCC 29133.

    PubMed

    Moirangthem, Lakshmipyari Devi; Bhattacharya, Sudeshna; Stensjö, Karin; Lindblad, Peter; Bhattacharya, Jyotirmoy

    2014-04-01

    A spontaneous methyl viologen (MV)-resistant mutant of the nitrogen-fixing cyanobacterium Nostoc punctiforme ATCC 29133 was isolated and the major enzymatic antioxidants involved in combating MV-induced oxidative stress were evaluated. The mutant displayed a high constitutive catalase activity as a consequence of which, the intracellular level of reactive oxygen species in the mutant was lower than the wild type (N. punctiforme) in the presence of MV. The superoxide dismutase (SOD) activity that consisted of a SodA (manganese-SOD) and a SodB (iron-SOD) was not suppressed in the mutant following MV treatment. The mutant was, however, characterised by a lower peroxidase activity compared with its wild type, and its improved tolerance to externally added H₂O₂ could only be attributed to enhanced catalase activity. Furthermore, MV-induced toxic effects on the wild type such as (1) loss of photosynthetic performance assessed as maximal quantum yield of photosystem II, (2) nitrogenase inactivation, and (3) filament fragmentation and cell lysis were not observed in the mutant. These findings highlight the importance of catalase in preventing MV-promoted oxidative damage and cell death in the cyanobacterium N. punctiforme. Such oxidative stress resistant mutants of cyanobacteria are likely to be a better source of biofertilisers, as they can grow and fix nitrogen in an unhindered manner in agricultural fields that are often contaminated with the herbicide MV, also commonly known as paraquat.

  1. Phenotypic and genotypic characterization of multiple strains of the diazotrophic cyanobacterium, Crocosphaera watsonii, isolated from the open ocean.

    PubMed

    Webb, Eric A; Ehrenreich, Ian M; Brown, Susan L; Valois, Frederica W; Waterbury, John B

    2009-02-01

    Diazotrophic cyanobacteria have long been recognized as important sources of reduced nitrogen (N) and therefore are important ecosystem components. Until recently, species of the filamentous cyanobacterium Trichodesmium were thought to be the primary sources of fixed N to the open ocean euphotic zone. It is now recognized that unicellular cyanobacteria are also important contributors, with members of the oligotrophic genus Crocosphaera being the only cultured examples. Herein we genetically and phenotypically characterize 10 strains isolated from the tropical Atlantic and North Pacific Oceans, and show that although all of the strains are highly similar at the genetic level, with the internal transcribed sequence (ITS) region sequence varying by approximately 2 bp on average, there are many unexpected phenotypic differences between the isolates (e.g. cell size, temperature optima and range, extracellular material excretion and variability in rates of nitrogen fixation). However based on the observed sequence similarity, we propose that all of these isolates are members of the genus Crocosphaera (type strain Crocosphaera watsonii WH8501), and that the phenotypic diversity we see may reflect ecologically important variation relevant for modelling N(2) fixation in the oligotrophic ocean.

  2. Economic Growth.

    ERIC Educational Resources Information Center

    O'Neill, James B.; And Others

    1986-01-01

    A conceptual introduction for teachers explains economic growth and how it is measured. Four instructional units follow, beginning with a preschool and kindergarten unit which offers young students an opportunity to interview puppet workers, set up a classroom corner store, and learn the importance of capital resources for increasing productivity…

  3. Genetic structure of the rattan Calamus thwaitesii in core, buffer and peripheral regions of three protected areas in central Western Ghats, India: do protected areas serve as refugia for genetic resources of economically important plants?

    PubMed

    Ramesha, B T; Ravikanth, G; Nageswara Rao, M; Ganeshaiah, K N; Uma Shaanker, R

    2007-04-01

    Given the increasing anthropogenic pressures on forests, the various protected areas--national parks, sanctuaries, and biosphere reserves--serve as the last footholds for conserving biological diversity. However, because protected areas are often targeted for the conservation of selected species, particularly charismatic animals, concerns have been raised about their effectiveness in conserving nontarget taxa and their genetic resources. In this paper, we evaluate whether protected areas can serve as refugia for genetic resources of economically important plants that are threatened due to extraction pressures. We examine the population structure and genetic diversity of an economically important rattan, Calamus thwaitesii, in the core, buffer and peripheral regions of three protected areas in the central Western Ghats, southern India. Our results indicate that in all the three protected areas, the core and buffer regions maintain a better population structure, as well as higher genetic diversity, than the peripheral regions of the protected area. Thus, despite the escalating pressures of extraction, the protected areas are effective in conserving the genetic resources of rattan. These results underscore the importance of protected areas in conservation of nontarget species and emphasize the need to further strengthen the protected-area network to offer refugia for economically important plant species.

  4. Bloom of the cyanobacterium Moorea bouillonii on the gorgonian coral Annella reticulata in Japan

    PubMed Central

    Yamashiro, Hideyuki; Isomura, Naoko; Sakai, Kazuhiko

    2014-01-01

    Coral populations are in decline due to environmental changes and biological attacks by predators and infectious diseases. Here, we report a localized bloom of the benthic filamentous cyanobacterium Moorea bouillonii (formerly Lyngbya bouillonii) observed exclusively on the gorgonian (sea fan) coral Annella reticulata at around 20 m depth in Japan. The degree of infection has reached 26% among different sizes of Annella colonies. Thick and continuous growth of Moorea may be sustained partly by symbiotic alpheid shrimp, which affix Moorea filaments to gorgonian corals for use as food and shelter. Most filaments get entangled on the coral colony, some penetrate into the stem of the coral with a swollen end like a root hair, which appears to function as an anchor in Annella. In addition to the cyanobacterium–shrimp interaction, the new trait of anchoring by the cyanobacterium into gorgonian coral may contribute to persistence of this bloom. PMID:25112498

  5. Identification of a new-to-science cyanobacterium, Toxifilum mysidocida gen. nov. & sp. nov. (Cyanobacteria, Cyanophyceae).

    PubMed

    Zimba, Paul V; Huang, I-Shuo; Foley, Jennifer E; Linton, Eric W

    2017-02-01

    Cyanobacteria occupy many niches within terrestrial, planktonic, and benthic habitats. The diversity of habitats colonized, similarity of morphology, and phenotypic plasticity all contribute to the difficulty of cyanobacterial identification. An unknown marine filamentous cyanobacterium was isolated from an aquatic animal rearing facility having mysid mortality events. The cyanobacterium originated from Corpus Christi Bay, TX. Filaments are rarely solitary, benthic mat forming, unbranched, and narrowing at the ends. Cells are 2.1 × 3.1 μm (width × length). Thylakoids are peripherally arranged on the outer third of the cell; cyanophycin granules and polyphosphate bodies are present. Molecular phylogenetic analysis in addition to morphology (transmission electron microscopy and scanning electron microscopy) and chemical composition all confirm it as a new genus and species we name Toxifilum mysidocida. At least one identified Leptolyngbya appears (based on genetic evidence and TEM) to belong to this new genus.

  6. Cyanobacterium Microcystis aeruginosa response to pentachlorophenol and comparison with that of the microalga Chlorella vulgaris.

    PubMed

    de Morais, Paulo; Stoichev, Teodor; Basto, M Clara P; Ramos, V; Vasconcelos, V M; Vasconcelos, M Teresa S D

    2014-04-01

    Pentachlorophenol (PCP) effects on a strain of the cyanobacterium Microcystis aeruginosa were investigated at laboratory scale. This is the first systematic ecotoxicity study of the effects of PCP on an aquatic cyanobacterium. The microalga Chlorella vulgaris was studied in the same conditions as the cyanobacterium, in order to compare the PCP toxicity and its removal by the species. The cells were exposed to environmental levels of PCP during 10 days, in Fraquil culture medium, at nominal concentrations from 0.01 to 1000 μg L(-1), to the cyanobacterium, and 0.01 to 5000 μg L(-1), to the microalga. Growth was assessed by area under growth curve (AUC, optical density vs time) and chlorophyll a content (chla). The toxicity profiles of the two species were very different. The calculated effective concentrations EC20 and EC50 were much lower to M. aeruginosa, and its growth inhibition expressed by chla was concentration-dependent while by AUC was not concentration-dependent. The cells might continue to divide even with lower levels of chla. The number of C. vulgaris cells decreased with the PCP concentration without major impact on the chla. The effect of PCP on M. aeruginosa is hormetic: every concentration studied was toxic except 1 μg L(-1), which promoted its growth. The legal limit of PCP set by the European Union for surface waters (1 μg L(-1)) should be reconsidered since a toxic cyanobacteria bloom might occur. The study of the removal of PCP from the culture medium by the two species is an additional novelty of this work. M. aeruginosa could remove part of the PCP from the medium, at concentrations where toxic effects were observed, while C. vulgaris stabilized it. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Aeruginazole A, a novel thiazole-containing cyclopeptide from the cyanobacterium Microcystis sp.

    PubMed

    Raveh, Avi; Carmeli, Shmuel

    2010-08-06

    A novel thiazole-containing cyclic peptide, aeruginazole A (1), was isolated from the cyanobacterium Microcystis sp. strain (IL-323), which was collected from a water reservoir near Kfar-Yehoshua, Valley of Armageddon, Israel. The planar structure of aeruginazole A was established using homonuclear and inverse-heteronuclear 2D NMR techniques, as well as high-resolution mass spectrometry. The absolute configuration of the asymmetric centers was determined using Marfey's method. Aeruginazole A potently inhibited Bacillus subtilis.

  8. Alotamide A, a Novel Neuropharmacological Agent From the Marine Cyanobacterium Lyngbya bouillonii

    PubMed Central

    Soria-Mercado, Irma E.; Pereira, Alban; Cao, Zhengyu; Murray, Thomas F.; Gerwick, William H.

    2009-01-01

    Alotamide A (1), a structurally intriguing cyclic depsipeptide, was isolated from the marine mat-forming cyanobacterium Lyngbya bouillonii collected in Papua New Guinea. It features three contiguous peptidic residues and an unsaturated heptaketide with oxidations and methylations unlike those found in any other marine cyanobacterial metabolite. Pure alotamide A (1) displays an unusual calcium influx activation profile in murine cerebrocortical neurons with an EC50 of 4.18 μM. PMID:19754100

  9. Draft Genome Sequence of the Toxic Bloom-Forming Cyanobacterium Aphanizomenon flos-aquae NIES-81.

    PubMed

    Cao, Huansheng; Shimura, Yohei; Masanobu, Kawachi; Yin, Yanbin

    2014-02-13

    Aphanizomenon flos-aquae is a toxic filamentous cyanobacterium that causes water blooms in freshwaters across the globe. We present the draft genome sequence of the A. flos-aquae strain NIES-81, which was determined by 454 pyrosequencing technology. The draft genome is ~5.7 Mb, containing 5,802 predicted protein-coding genes and 58 RNA genes, with a G+C content of 38.5%.

  10. Draft Genome Sequence of the Toxic Bloom-Forming Cyanobacterium Aphanizomenon flos-aquae NIES-81

    PubMed Central

    Cao, Huansheng; Shimura, Yohei; Masanobu, Kawachi

    2014-01-01

    Aphanizomenon flos-aquae is a toxic filamentous cyanobacterium that causes water blooms in freshwaters across the globe. We present the draft genome sequence of the A. flos-aquae strain NIES-81, which was determined by 454 pyrosequencing technology. The draft genome is ~5.7 Mb, containing 5,802 predicted protein-coding genes and 58 RNA genes, with a G+C content of 38.5%. PMID:24526634

  11. Draft Genome Assembly of a Filamentous Euendolithic (True Boring) Cyanobacterium, Mastigocoleus testarum Strain BC008

    PubMed Central

    Guida, Brandon S.

    2016-01-01

    Mastigocoleus testarum strain BC008 is a model organism used to study marine photoautotrophic carbonate dissolution. It is a multicellular, filamentous, diazotrophic, euendolithic cyanobacterium ubiquitously found in marine benthic environments. We present an accurate draft genome assembly of 172 contigs spanning 12,700,239 bp with 9,131 annotated genes with an average G+C% of 37.3. PMID:26823575

  12. Comparative genomic analyses of the cyanobacterium, Lyngbya aestuarii BL J, a powerful hydrogen producer

    PubMed Central

    Kothari, Ankita; Vaughn, Michael; Garcia-Pichel, Ferran

    2013-01-01

    The filamentous, non-heterocystous cyanobacterium Lyngbya aestuarii is an important contributor to marine intertidal microbial mats system worldwide. The recent isolate L. aestuarii BL J, is an unusually powerful hydrogen producer. Here we report a morphological, ultrastructural, and genomic characterization of this strain to set the basis for future systems studies and applications of this organism. The filaments contain circa 17 μm wide trichomes, composed of stacked disk-like short cells (2 μm long), encased in a prominent, laminated exopolysaccharide sheath. Cellular division occurs by transversal centripetal growth of cross-walls, where several rounds of division proceed simultaneously. Filament division occurs by cell self-immolation of one or groups of cells (necridial cells) at the breakage point. Short, sheath-less, motile filaments (hormogonia) are also formed. Morphologically and phylogenetically L. aestuarii belongs to a clade of important cyanobacteria that include members of the marine Trichodesmiun and Hydrocoleum genera, as well as terrestrial Microcoleus vaginatus strains, and alkalyphilic strains of Arthrospira. A draft genome of strain BL J was compared to those of other cyanobacteria in order to ascertain some of its ecological constraints and biotechnological potential. The genome had an average GC content of 41.1%. Of the 6.87 Mb sequenced, 6.44 Mb was present as large contigs (>10,000 bp). It contained 6515 putative protein-encoding genes, of which, 43% encode proteins of known functional role, 26% corresponded to proteins with domain or family assignments, 19.6% encode conserved hypothetical proteins, and 11.3% encode apparently unique hypothetical proteins. The strain's genome reveals its adaptations to a life of exposure to intense solar radiation and desiccation. It likely employs the storage compounds, glycogen, and cyanophycin but no polyhydroxyalkanoates, and can produce the osmolytes, trehalose, and glycine betaine. According to its

  13. Cell envelope components influencing filament length in the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120.

    PubMed

    Burnat, Mireia; Schleiff, Enrico; Flores, Enrique

    2014-12-01

    Heterocyst-forming cyanobacteria grow as chains of cells (known as trichomes or filaments) that can be hundreds of cells long. The filament consists of individual cells surrounded by a cytoplasmic membrane and peptidoglycan layers. The cells, however, share a continuous outer membrane, and septal proteins, such as SepJ, are important for cell-cell contact and filament formation. Here, we addressed a possible role of cell envelope components in filamentation, the process of producing and maintaining filaments, in the model cyanobacterium Anabaena sp. strain PCC 7120. We studied filament length and the response of the filaments to mechanical fragmentation in a number of strains with mutations in genes encoding cell envelope components. Previously published peptidoglycan- and outer membrane-related gene mutants and strains with mutations in two genes (all5045 and alr0718) encoding class B penicillin-binding proteins isolated in this work were used. Our results show that filament length is affected in most cell envelope mutants, but the filaments of alr5045 and alr2270 gene mutants were particularly fragmented. All5045 is a dd-transpeptidase involved in peptidoglycan elongation during cell growth, and Alr2270 is an enzyme involved in the biosynthesis of lipid A, a key component of lipopolysaccharide. These results indicate that both components of the cell envelope, the murein sacculus and the outer membrane, influence filamentation. As deduced from the filament fragmentation phenotypes of their mutants, however, none of these elements is as important for filamentation as the septal protein SepJ.

  14. Integration of carbon and nitrogen metabolism with energy production is crucial to light acclimation in the cyanobacterium Synechocystis.

    PubMed

    Singh, Abhay K; Elvitigala, Thanura; Bhattacharyya-Pakrasi, Maitrayee; Aurora, Rajeev; Ghosh, Bijoy; Pakrasi, Himadri B

    2008-09-01

    Light drives the production of chemical energy and reducing equivalents in photosynthetic organisms required for the assimilation of essential nutrients. This process also generates strong oxidants and reductants that can be damaging to the cellular processes, especially during absorption of excess excitation energy. Cyanobacteria, like other oxygenic photosynthetic organisms, respond to increases in the excitation energy, such as during exposure of cells to high light (HL) by the reduction of antenna size and photosystem content. However, the mechanism of how Synechocystis sp. PCC 6803, a cyanobacterium, maintains redox homeostasis and coordinates various metabolic processes under HL stress remains poorly understood. In this study, we have utilized time series transcriptome data to elucidate the global responses of Synechocystis to HL. Identification of differentially regulated genes involved in the regulation, protection, and maintenance of redox homeostasis has offered important insights into the optimized response of Synechocystis to HL. Our results indicate a comprehensive integrated homeostatic interaction between energy production (photosynthesis) and energy consumption (assimilation of carbon and nitrogen). In addition, measurements of physiological parameters under different growth conditions showed that integration between the two processes is not a consequence of limitations in the external carbon and nitrogen levels available to the cells. We have also discovered the existence of a novel glycosylation pathway, to date known as an important nutrient sensor only in eukaryotes. Up-regulation of a gene encoding the rate-limiting enzyme in the hexosamine pathway suggests a regulatory role for protein glycosylation in Synechocystis under HL.

  15. Influence of Leaching Parameters on the Biological Removal of Uranium from Coal by a Filamentous Cyanobacterium

    PubMed Central

    Lorenz, Michael G.; Krumbein, Wolfgang E.

    1985-01-01

    Axenic cultures of the filamentous cyanobacterium LPP OL3 were incubated with samples of uraniumbearing coal from a German mining area. The influence of leaching parameters such as coal concentration (pulp density), initial biomass, particle size, temperature, and composition of the growth medium on the leaching of uranium from the ore by the cyanobacterial strain was studied. When low pulp densities were applied, the yield of biologically extracted uranium was optimal (reaching 96% at 1% [wt/vol] coal) and all released uranium was found in the culture liquid. Above 10% (wt/vol) coal in the medium, the amount of cell-bound uranium increased. Initial biomass concentration (protein content of the cultures) and particle size were not critical parameters of leaching by LPP OL3. However, temperature and composition of the growth medium profoundly influenced the leaching of uranium and growth of the cyanobacterium. The yield of leached uranium (at 10% [wt/vol] coal) could not be raised with a tank leaching apparatus. Also, coal ashes were not suitable substrates for the leaching of uranium by LPP OL3. In conclusion, the reactions of the cyanobacterium to variations in leaching parameters were different from reactions of acidic leaching organisms. Images PMID:16346934

  16. Role of manganese in protection against oxidative stress under iron starvation in cyanobacterium Anabaena 7120.

    PubMed

    Kaushik, Manish Singh; Srivastava, Meenakshi; Verma, Ekta; Mishra, Arun Kumar

    2015-06-01

    The cyanobacterium Anabaena sp. PCC 7120 was grown in presence and absence of iron to decipher the role of manganese in protection against the oxidative stress under iron starvation and growth, manganese uptake kinetics, antioxidative enzymes, lipid peroxidation, electrolyte leakage, thiol content, total peroxide, proline and NADH content was investigated. Manganese supported the growth of cyanobacterium Anabaena 7120 under iron deprived conditions where maximum uptake rate of manganese was observed with lower K(m) and higher V(max) values. Antioxidative enzymes were also found to be elevated in iron-starved conditions. Estimation of lipid peroxidation and electrolyte leakage depicted the role of manganese in stabilizing the integrity of the membrane which was considered as the prime target of oxygen free radicals in oxidative stress. The levels of total peroxide, thiol, proline and NADH content, which are the representative of oxidative stress response in Anabaena 7120, were also showed increasing trends in iron starvation. Hence, the results discerned, clearly suggested the role of manganese in protection against the oxidative stress in cyanobacterium Anabaena 7120 under iron starvation either due to its antioxidative properties or involvement as cofactor in a number of antioxidative enzymes.

  17. Ecological genomics of the newly discovered diazotrophic filamentous cyanobacterium ESFC-1

    NASA Astrophysics Data System (ADS)

    Everroad, C.; Bebout, B.; Bebout, L. E.; Detweiler, A. M.; Lee, J.; Mayali, X.; Singer, S. W.; Stuart, R.; Weber, P. K.; Woebken, D.; Pett-Ridge, J.

    2014-12-01

    Cyanobacteria-dominated microbial mats played a key role in the evolution of the early Earth and provide a model for exploring the relationships between ecology, evolution and biogeochemistry. A recently described nonheterocystous filamentous cyanobacterium, strain ESFC-1, has been shown to be a major diazotroph year round in the intertidal microbial mat system at Elkhorn Slough, CA, USA. Based on phylogenetic analyses of the 16s RNA gene, ESFC-1 appears to belong to a unique, genus-level divergence within the cyanobacteria. Consequently, the draft genome sequence of this strain has been determined. Here we report features of this genome, particularly as they relate to the ecological functions and capabilities of strain ESFC-1. One striking feature of this cyanobacterium is the apparent lack of a functional bi-directional hydrogenase typically expected to be found within a diazotroph; consortia- and culture-based experiments exploring the metabolic processes of ESFC-1 also indicate that this hydrogenase is absent. Co-culture studies with ESFC-1 and some of the dominant heterotrophic members within the microbial mat system, including the ubiquitous Flavobacterium Muricauda sp., which often is found associated with cyanobacteria in nature and in culture collections worldwide, have also been performed. We report on these species-species interactions, including materials exchange between the cyanobacterium and heterotrophic bacterium. The combination of genomics with culture- and consortia-based experimental research is a powerful tool for understanding microbial processes and interactions in complex ecosystems.

  18. Construction, implementation and testing of an image identification system using computer vision methods for fruit flies with economic importance (Diptera: Tephritidae).

    PubMed

    Wang, Jiang-Ning; Chen, Xiao-Lin; Hou, Xin-Wen; Zhou, Li-Bing; Zhu, Chao-Dong; Ji, Li-Qiang

    2017-07-01

    Many species of Tephritidae are damaging to fruit, which might negatively impact international fruit trade. Automatic or semi-automatic identification of fruit flies are greatly needed for diagnosing causes of damage and quarantine protocols for economically relevant insects. A fruit fly image identification system named AFIS1.0 has been developed using 74 species belonging to six genera, which include the majority of pests in the Tephritidae. The system combines automated image identification and manual verification, balancing operability and accuracy. AFIS1.0 integrates image analysis and expert system into a content-based image retrieval framework. In the the automatic identification module, AFIS1.0 gives candidate identification results. Afterwards users can do manual selection based on comparing unidentified images with a subset of images corresponding to the automatic identification result. The system uses Gabor surface features in automated identification and yielded an overall classification success rate of 87% to the species level by Independent Multi-part Image Automatic Identification Test. The system is useful for users with or without specific expertise on Tephritidae in the task of rapid and effective identification of fruit flies. It makes the application of computer vision technology to fruit fly recognition much closer to production level. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  19. The siderophilic cyanobacterium Leptolyngbya sp. strain JSC-1 acclimates to iron starvation by expressing multiple isiA-family genes.

    PubMed

    Shen, Gaozhong; Gan, Fei; Bryant, Donald A

    2016-06-01

    In the evolution of different cyanobacteria performing oxygenic photosynthesis, the core complexes of the two photosystems were highly conserved. However, cyanobacteria exhibit significant diversification in their light-harvesting complexes and have flexible regulatory mechanisms to acclimate to changes in their growth environments. In the siderophilic, filamentous cyanobacterium, Leptolyngbya sp. strain JSC-1, five different isiA-family genes occur in two gene clusters. During acclimation to Fe limitation, relative transcript levels for more than 600 genes increased more than twofold. Relative transcript levels were ~250 to 300 times higher for the isiA1 gene cluster (isiA1-isiB-isiC), and ~440- to 540-fold for the isiA2-isiA3-isiA4-cpcG2-isiA5 gene cluster after 48 h of iron starvation. Chl-protein complexes were isolated and further purified from cells grown under Fe-replete and Fe-depleted conditions. A single class of particles, trimeric PSI, was identified by image analysis of electron micrographs of negatively stained PSI complexes from Fe-replete cells. However, three major classes of particles were observed for the Chl-protein supercomplexes from cells grown under iron starvation conditions. Based on LC-MS-MS analyses, the five IsiA-family proteins were found in the largest supercomplexes together with core components of the two photosystems; however, IsiA5 was not present in complexes in which only the core subunits of PSI were detected. IsiA5 belongs to the same clade as PcbC proteins in a phylogenetic classification, and it is proposed that IsiA5 is most likely involved in supercomplexes containing PSII dimers. IsiA4, which is a fusion of an IsiA domain and a C-terminal PsaL domain, was found together with IsiA1, IsiA2, and IsiA3 in complexes with monomeric PSI. The data indicate that horizontal gene transfer, gene duplication, and divergence have played important roles in the adaptive evolution of this cyanobacterium to iron starvation conditions.

  20. Long-term economic impact of countervailing duties on coated free sheet paper imported by the United States from China, the Republic of Korea, and Indonesia

    Treesearch

    Shushuai Zhu; James A. Turner; Joseph Buongiorno

    2008-01-01

    The international effects of United States countervailing duties on imports of coated free sheet paper from China, the Republic of Korea, and Indonesia were predicted with the Global Forest Products Model, up to the year 2020. The results indicate that the production of printing and writing paper in China, Indonesia, and the Republic of Korea would be lower. The trade...

  1. Abattoir prevalence, organ distribution, public health and economic importance of major metacestodes in sheep, goats and cattle in Fars, southern Iran.

    PubMed

    Oryan, A; Goorgipour, S; Moazeni, M; Shirian, S

    2012-09-01

    Some of the metacestodes are not only zoonotic but are also responsible for severe tissue damage, reduction in milk and meat production, and considerable economic loss due to condemnation of the infected organs of the herbivorous animals. The aim of the present study was to determine the prevalence of Cysticercus ovis, Cysticercus tenuicollis, hydatid cyst and Coenurus gaigeri in sheep and goats and Cysticercus bovis, Cysticereus tenuicollis and hydatid cyst in cattle. A total of 1050 sheep, 950 goats and 500 cattle slaughtered at Shiraz Slaughterhouse were carefully examined for these metacestodes. Cysticercus tenuicollis was found in 184 (17.52%) sheep and 523 (55.05%) goats. The prevalence of C. tenuicollis was higher in males than females (P<0.01), and was higher in goats compared to sheep (P<0.01). Hydatid cyst was found in 478 (45.52%) sheep and 95 (10.0%) goats and its prevalence was higher in older animals compared to the younger ones. Coenurus gaigeri was found in 5 (0.48%) sheep and 17 (1.79%) goats and Cysticercus ovis was found in one male sheep only (0.09%). Cysticercus bovis was found in 3 male cattle (0.6%) and hydatid cyst was found in 58 (11.6%) cattle. The prevalence of hydatid cyst was higher in older cattle compared to the younger ones and higher in females than males. These results suggest that the high prevalence of the metacestodes infestations in this area is a great concern for both medical and veterinary authorities to design therapeutic and preventive programs to overcome this problem.

  2. Prevalence, risk factors and economic importance of infestations with Sarcoptes scabiei and Haematopinus suis in sows of pig breeding farms in Hesse, Germany.

    PubMed

    Damriyasa, I M; Failing, K; Volmer, R; Zahner, H; Bauer, C

    2004-12-01

    A cross-sectional survey was performed in 110 randomly selected pig-breeding farms of southern Hesse, Germany to estimate the prevalence of ectoparasite infestations and to find possible risk factors. Ear scrapings of, if available, 10 sows per farm were examined for Sarcoptes scabiei var. suis (De Geer) (Acaridida: Sarcoptidae) by the potassium hydroxide digestion method, and a total of 2754 sows was inspected for skin lesions and infestations with Haematopinus suis (L.) (Anoplurida: Haematopinidae). Data on farm profiles and sows were collected by a questionnaire. In total, 19.1% and 2.5% of the sows were found to be infested with S. scabiei or H. suis, respectively. The percentage of mite or louse infestation was significantly higher in sows showing pruritus than in those without skin lesions. Both ectoparasite infestations were related neither to the age of sows nor their reproduction status, nor to the time interval to last ectoparasite treatment. Using farms as the unit of analysis, the estimated prevalence of mange mite and louse infestations was 45.4% and 14.5%, respectively. There was no significant association between the presence of S. scabiei and H. suis in the farms. Risk factors for S. scabiei infestation were mixed housing of dry and nursing sows in the same unit (vs. separate housing) and straw bedding (vs. strawless). For louse infestation, only mechanical cleaning of stable units (vs. additional use of disinfection methods) and pasturing of gilts and dry sows were identified as risk factors. The economic loss by S. scabiei infestation in the study population was assessed at euro 4200 per affected farm and year on average.

  3. Halotolerant cyanobacterium Aphanothece halophytica contains NapA-type Na+/H+ antiporters with novel ion specificity that are involved in salt tolerance at alkaline pH.

    PubMed

    Wutipraditkul, Nuchanat; Waditee, Rungaroon; Incharoensakdi, Aran; Hibino, Takashi; Tanaka, Yoshito; Nakamura, Tatsunosuke; Shikata, Masamitsu; Takabe, Tetsuko; Takabe, Teruhiro

    2005-08-01

    Aphanothece halophytica is a halotolerant alkaliphilic cyanobacterium which can grow at NaCl concentrations up to 3.0 M and at pH values up to 11. The genome sequence revealed that the cyanobacterium Synechocystis sp. strain PCC 6803 contains five putative Na+/H+ antiporters, two of which are homologous to NhaP of Pseudomonas aeruginosa and three of which are homologous to NapA of Enterococcus hirae. The physiological and functional properties of NapA-type antiporters are largely unknown. One of NapA-type antiporters in Synechocystis sp. strain PCC 6803 has been proposed to be essential for the survival of this organism. In this study, we examined the isolation and characterization of the homologous gene in Aphanothece halophytica. Two genes encoding polypeptides of the same size, designated Ap-napA1-1 and Ap-napA1-2, were isolated. Ap-NapA1-1 exhibited a higher level of homology to the Synechocystis ortholog (Syn-NapA1) than Ap-NapA1-2 exhibited. Ap-NapA1-1, Ap-NapA1-2, and Syn-NapA1 complemented the salt-sensitive phenotypes of an Escherichia coli mutant and exhibited strongly pH-dependent Na+/H+ and Li+/H+ exchange activities (the highest activities were at alkaline pH), although the activities of Ap-NapA1-2 were significantly lower than the activities of the other polypeptides. Only one these polypeptides, Ap-NapA1-2, complemented a K+ uptake-deficient E. coli mutant and exhibited K+ uptake activity. Mutagenesis experiments suggested the importance of Glu129, Asp225, and Asp226 in the putative transmembrane segment and Glu142 in the loop region for the activity. Overexpression of Ap-NapA1-1 in the freshwater cyanobacterium Synechococcus sp. strain PCC 7942 enhanced the salt tolerance of cells, especially at alkaline pH. These findings indicate that A. halophytica has two NapA1-type antiporters which exhibit different ion specificities and play an important role in salt tolerance at alkaline pH.

  4. CRISPR/Cas9 mediated targeted mutagenesis of the fast growing cyanobacterium Synechococcus elongatus UTEX 2973

    SciTech Connect

    Wendt, Kristen E.; Ungerer, Justin; Cobb, Ryan E.; Zhao, Huimin; Pakrasi, Himadri B.

    2016-06-23

    As autotrophic prokaryotes, cyanobacteria are ideal chassis organisms for sustainable production of various useful compounds. The newly characterized cyanobacterium Synechococcus elongatus UTEX 2973 is a promising candidate for serving as a microbial cell factory because of its unusually rapid growth rate. Here, we seek to develop a genetic toolkit that enables extensive genomic engineering of Synechococcus 2973 by implementing a CRISPR/Cas9 editing system. We targeted the nblA gene because of its important role in biological response to nitrogen deprivation conditions. First, we determined that the Streptococcus pyogenes Cas9 enzyme is toxic in cyanobacteria, and conjugational transfer of stable, replicating constructs containing the cas9 gene resulted in lethality. However, after switching to a vector that permitted transient expression of the cas9 gene, we achieved markerless editing in 100 % of cyanobacterial exconjugants after the first patch. Moreover, we could readily cure the organisms of antibiotic resistance, resulting in a markerless deletion strain. In conclusion, high expression levels of the Cas9 protein in Synechococcus 2973 appear to be toxic and result in cell death. However, introduction of a CRISPR/Cas9 genome editing system on a plasmid backbone that leads to transient cas9 expression allowed for efficient markerless genome editing in a wild type genetic background.

  5. Functional characterization of a member of alanine or glycine: cation symporter family in halotolerant cyanobacterium Aphanothece halophytica.

    PubMed

    Bualuang, Aporn; Kageyama, Hakuto; Tanaka, Yoshito; Incharoensakdi, Aran; Takabe, Teruhiro

    2015-01-01

    Membrane proteins of amino acid-polyamine-organocation (APC) superfamily transport amino acids and amines across membranes and play important roles in the regulation of cellular processes. The alanine or glycine: cation symporter (AGCS) family belongs to APC superfamily and is found in prokaryotes, but its substrate specificity remains to be clarified. In this study, we found that a halotolerant cyanobacterium, Aphanothece halophytica has two putative ApagcS genes. The deduced amino acid sequence of one of genes, ApagcS1, exhibited high homology to Pseudomonas AgcS. The ApagcS1 gene was expressed in Escherichia coli JW4166 which is deficient in glycine uptake. Kinetics studies in JW4166 revealed that ApAgcS1 is a sodium-dependent glycine transporter. Competition experiments showed the significant inhibition by glutamine, asparagine, and glycine. The level of mRNA for ApagcS1 was induced by NaCl and nitrogen-deficient stresses. Uptake of glutamine by ApAgcS1 was also observed. Based on these data, the physiological role of ApAgcS1 was discussed.

  6. Seawater cultivation of freshwater cyanobacterium Synechocystis sp. PCC 6803 drastically alters amino acid composition and glycogen metabolism

    PubMed Central

    Iijima, Hiroko; Nakaya, Yuka; Kuwahara, Ayuko; Hirai, Masami Yokota; Osanai, Takashi

    2015-01-01

    Water use assessment is important for bioproduction using cyanobacteria. For eco-friendly reasons, seawater should preferably be used for cyanobacteria cultivation instead of freshwater. In this study, we demonstrated that the freshwater unicellular cyanobacterium Synechocystis sp. PCC 6803 could be grown in a medium based on seawater. The Synechocystis wild-type strain grew well in an artificial seawater (ASW) medium supplemented with nitrogen and phosphorus sources. The addition of HEPES buffer improved cell growth overall, although the growth in ASW medium was inferior to that in the synthetic BG-11 medium. The levels of proteins involved in sugar metabolism changed depending on the culture conditions. The biosynthesis of several amino acids including aspartate, glutamine, glycine, proline, ornithine, and lysine, was highly up-regulated by cultivation in ASW. Two types of natural seawater (NSW) were also made available for the cultivation of Synechocystis cells, with supplementation of both nitrogen and phosphorus sources. These results revealed the potential use of seawater for the cultivation of freshwater cyanobacteria, which would help to reduce freshwater consumption during biorefinery using cyanobacteria. PMID:25954257

  7. Do we Underestimate the Importance of Leaf Size in Plant Economics? Disproportional Scaling of Support Costs Within the Spectrum of Leaf Physiognomy

    PubMed Central

    Niinemets, Ülo; Portsmuth, Angelika; Tena, David; Tobias, Mari; Matesanz, Silvia; Valladares, Fernando

    2007-01-01

    characteristics differed among mid-ribs, petioles and laminas, implying that the mass-weighted average leaf N and C percentage, density, and dry to fresh mass ratio can have different functional values depending on the importance of within-leaf support investments. Conclusions These data demonstrate that variation in leaf size is associated with major changes in within-leaf support investments and in large modifications in integrated leaf chemical and structural characteristics. These size-dependent alterations can importantly affect general leaf structure vs. function scaling relationships. These data further demonstrate important life-form effects on and climatic differentiation in foliage support costs. PMID:17586597

  8. [Economic crime].

    PubMed

    Dinitz, S

    1976-01-01

    Economic crime, often also referred to as white collar crime, is one of the most incidious and predatory of offenses. Unlike street crime, for which there may well be some protection, the average citizen is completely at the mercy of the perpetrators of economic crimes. The concept of white collar crime was first identified by Edwin H. Sutherland. He dealt with the problem as a violation of trust involving either or both misrepresentation and duplicity. He argued for the use of criminal sanctions rather than civil remedies as a means of dealing with white collar offenses. Sutherland's views were attacked by the legal profession, by sociologists and criminologists and by public opinion specialists. They contended that an act treated in civil court is not a crime; that criminals are those persons who are defined as such and white collar criminals are neither so defined nor do they define themselves as criminals and, finally, that economic crime is universal. Can anyone be criminal, then, ask the critics? A number of studies by Clinard, Quinney, Black, Ball, Cressey, Newman and others have translated the interest in white collar crime into empirical terms. The last thirty-five years have also witnessed the elaboration and alteration of the theory itself. Geis' work has been particularly important in this respect. His "street" versus "suite" crime is a useful dichotomy. Most important, however, have been the monograph and papers by Herbert Edelhertz who has conceptualized the issues on various levels - from consumer fraud to the illegal activities of the multinational corporation. This article is concerned with the exposition of the theory and research in the field. Most significant, the paper raises serious doubts whether the problem of economic crime can be researched and studied; it raises even more difficult issues concerning the legal and sociological implications of economic crime and of its prevention, management and control.

  9. Effects of introgression on the genetic population structure of two ecologically and economically important conifer species: lodgepole pine (Pinus contorta var. latifolia) and jack pine (Pinus banksiana).

    PubMed

    Cullingham, Catherine I; Cooke, Janice E K; Coltman, David W

    2013-10-01

    Forest trees exhibit a remarkable range of adaptations to their environment, but as a result of frequent and long-distance gene flow, populations are often only weakly differentiated. Lodgepole and jack pine hybridize in western Canada, which adds the opportunity for introgression through hybridization to contribute to population structure and (or) adaptive variation. Access to large sample size, high density SNP datasets for these species would improve our ability to resolve population structure, parameterize introgression, and separate the influence of demography from adaptation. To accomplish this, 454 transcriptome reads for lodgepole and jack pine were assembled using Newbler and MIRA, the assemblies mined for SNPs, and 1536 SNPs were selected for typing on lodgepole pine, jack pine, and their hybrids (N = 536). We identified population structure using both Bayesian clustering and discriminate analysis of principle components. Introgressed SNP loci were identified and their influence on observed population structure was assessed. We found that introgressed loci resulted in increased differentiation both within lodgepole and jack pine populations. These findings are timely given the recent mountain pine beetle population expansion in the hybrid zone, and will facilitate future studies of adaptive traits in these ecologically important species.

  10. Economic impact

    SciTech Connect

    Technology Transfer Department

    2001-06-01

    In federal fiscal year 2000 (FY00), Berkeley Lab had 4,347 full- and part-time employees. In addition, at any given time of the year, there were more than 1,000 Laboratory guests. These guests, who also reside locally, have an important economic impact on the nine-county Bay Area. However, Berkeley Lab's total economic impact transcends the direct effects of payroll and purchasing. The direct dollars paid to the Lab's employees in the form of wages, salaries, and benefits, and payments made to contractors for goods and services, are respent by employees and contractors again and again in the local and greater economy. Further, while Berkeley Lab has a strong reputation for basic scientific research, many of the Lab's scientific discoveries and inventions have had direct application in industry, spawning new businesses and creating new opportunities for existing firms. This analysis updates the Economic Impact Analysis done in 1996, and its purpose is to describe the economic and geographic impact of Laboratory expenditures and to provide a qualitative understanding of how Berkeley Lab impacts and supports the local community. It is intended as a guide for state, local, and national policy makers as well as local community members. Unless otherwise noted, this analysis uses data from FY00, the most recent year for which full data are available.

  11. Trap capture of three economically important fruit fly species (Diptera: Tephritidae): evaluation of a solid formulation containing multiple male lures in a Hawaiian coffee field.

    PubMed

    Shelly, Todd; Nishimoto, Jon; Kurashima, Rick

    2012-08-01

    Invasive fruit flies (Diptera: Tephritidae) pose a global threat to agriculture through direct damage to food crops and the accompanying trade restrictions that often result. Early detection is vital to controlling fruit flies, because it increases the probability of limiting the growth and spread of the invasive population and thus may greatly reduce the monetary costs required for eradication or suppression. Male-specific lures are an important component of fruit fly detection, and three such lures are used widely: trimedlure (TML), cue lure (CL), and methyl eugenol (ME), attractive to Mediterranean fruit fly, Ceratitis capitata (Wiedemann); melon fly, Bactrocera cucurbitae (Coquillett); and oriental fruit fly, Bactrocera dorsalis (Hendel), respectively. In California, Florida, and Texas, the two Bactrocera lures are applied to separate species-specific traps as liquids (with a small amount of the insecticide naled added), whereas TML is delivered as a solid plug in another set of traps. Thus, the detection protocol involves considerable handling time as well as potential contact with a pesticide. The purpose of this study was to compare trap capture between liquid male lures and "trilure" wafers that contain TML, ME, raspberry ketone (RK, the hydroxy equivalent of CL), and the toxicant DDVP embedded within a solid matrix. Field studies were conducted in a Hawaiian coffee (Coffea arabica L.) field where the three aforementioned species co-occur, showed that the wafer captured at least as many flies as the liquid baits for all three species. This same result was obtained in comparisons using both fresh and aged (6-wk) baits. Moreover, the wafers performed as well as the single-lure traps in an ancillary experiment in which TML plugs were substituted for liquid TML. Additional experiments demonstrated explicitly that the presence of ME and RK had no effect on captures of C. capitata males and similarly that the presence of TML had no effect on the capture of B

  12. Acid-base physiology response to ocean acidification of two ecologically and economically important holothuroids from contrasting habitats, Holothuria scabra and Holothuria parva.

    PubMed

    Collard, Marie; Eeckhaut, Igor; Dehairs, Frank; Dubois, Philippe

    2014-12-01

    Sea cucumbers are dominant invertebrates in several ecosystems such as coral reefs, seagrass meadows and mangroves. As bioturbators, they have an important ecological role in making available calcium carbonate and nutrients to the rest of the community. However, due to their commercial value, they face overexploitation in the natural environment. On top of that, occurring ocean acidification could impact these organisms, considered sensitive as echinoderms are osmoconformers, high-magnesium calcite producers and have a low metabolism. As a first investigation of the impact of ocean acidification on sea cucumbers, we tested the impact of short-term (6 to 12 days) exposure to ocean acidification (seawater pH 7.7 and 7.4) on two sea cucumbers collected in SW Madagascar, Holothuria scabra, a high commercial value species living in the seagrass meadows, and H. parva, inhabiting the mangroves. The former lives in a habitat with moderate fluctuations of seawater chemistry (driven by day-night differences) while the second lives in a highly variable intertidal environment. In both species, pH of the coelomic fluid was significantly negatively affected by reduced seawater pH, with a pronounced extracellular acidosis in individuals maintained at pH 7.7 and 7.4. This acidosis was due to an increased dissolved inorganic carbon content and pCO2 of the coelomic fluid, indicating a limited diffusion of the CO2 towards the external medium. However, respiration and ammonium excretion rates were not affected. No evidence of accumulation of bicarbonate was observed to buffer the coelomic fluid pH. If this acidosis stays uncompensated for when facing long-term exposure, other processes could be affected in both species, eventually leading to impacts on their ecological role.

  13. A measles outbreak in Catania, Sicily: the importance of high vaccination coverage and early notification of cases for health and economic reasons.

    PubMed

    Celesia, Benedetto Maurizio; Fontana, Rossella; Pinzone, Marilia Rita; Cuccia, Mario; Bellissimo, Francesco; Rapisarda, Liliana; Rinnone, Sebastiano; Rapisarda, Venerando; Pavone, Piero; Cacopardo, Bruno; Nunnari, Giuseppe

    2014-09-01

    Measles is a paediatric exanthematous disease. Even though vaccination has dramatically reduced measles morbidity and mortality, outbreaks still occur due to insufficient vaccination coverage and importation of the virus from endemic regions. Although child vaccination coverage in Italy has been broadened (from 74% in 2000 to 90.1% in 2011), outbreaks are still observed at a regional level. We describe epidemiological and clinical characteristics of cases reported from January 2009 to May 2010 to the Epidemiology Service of the Provincial Health Authority of Catania. We obtained demographic data and vaccination status from the database of the Epidemiology Service and clinical features and laboratory data from medical records. In all, 522 cases were notified: 286 males (54%), median age 12 years (interquartile range (IQR) 4-18); 401 cases (77%) were notified by the hospital, and 121 (23%) by general practitioners. Only one patient had been previously vaccinated. 52 cases were hospitalized, median age 18 years (IQR 17-23). We observed hypertransaminasaemia in 20 patients (38%), thrombocytopenia in 22 patients (42%) and a creatine phosphokinase increase in 16 (30%). Complications (pneumonia, haemorrhagic cystitis, acute hepatitis) occurred in 10 patients (19%), all older than 18. Recent outbreaks show that immunization practices are still insufficient. Most cases were recorded in adolescents and young adults; even if the vaccine has limited virus circulation in childhood, it did not prevent the infection of other age groups. The number of notifications also suggests that the phenomenon is underestimated. In order to monitor the disease we need early notification of cases and increased vaccination coverage.

  14. A potent novel anti-HIV protein from the cultured cyanobacterium Scytonema varium.

    PubMed

    Bokesch, Heidi R; O'Keefe, Barry R; McKee, Tawnya C; Pannell, Lewis K; Patterson, Gregory M L; Gardella, Roberta S; Sowder, Raymond C; Turpin, Jim; Watson, Karen; Buckheit, Robert W; Boyd, Michael R

    2003-03-11

    A new anti-HIV protein, scytovirin, was isolated from aqueous extracts of the cultured cyanobacterium Scytonema varium. The protein displayed potent anticytopathic activity against laboratory strains and primary isolates of HIV-1 with EC50 values ranging from 0.3 to 22 nM. Scytovirin binds to viral coat proteins gp120, gp160, and gp41 but not to cellular receptor CD4 or other tested proteins. This unique protein consists of a single 95-amino acid chain with significant internal sequence duplication and 10 cysteines forming five intrachain disulfide bonds.

  15. Macrolactone Nuiapolide, Isolated from a Hawaiian Marine Cyanobacterium, Exhibits Anti-Chemotactic Activity

    PubMed Central

    Mori, Shogo; Williams, Howard; Cagle, Davey; Karanovich, Kristopher; Horgen, F. David; Smith, Roger; Watanabe, Coran M. H.

    2015-01-01

    A new bioactive macrolactone, nuiapolide (1) was identified from a marine cyanobacterium collected off the coast of Niihau, near Lehua Rock. The natural product exhibits anti-chemotactic activity at concentrations as low as 1.3 μM against Jurkat cells, cancerous T lymphocytes, and induces a G2/M phase cell cycle shift. Structural characterization of the natural product revealed the compound to be a 40-membered macrolactone with nine hydroxyl functional groups and a rare tert-butyl carbinol residue. PMID:26473885

  16. The amt gene cluster of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120.

    PubMed

    Paz-Yepes, Javier; Merino-Puerto, Victoria; Herrero, Antonia; Flores, Enrique

    2008-10-01

    The genome of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 bears a gene cluster including three amt genes that, based on homology of their protein products, we designate amt4, amt1, and amtB. Expression of the three genes took place upon ammonium withdrawal in combined nitrogen-free medium and was NtcA dependent. The genes were transcribed independently, but an amt4-amt1 dicistronic transcript was also produced, and expression was highest for the amt1 gene. A mutant with the whole amt region removed could grow under laboratory conditions using ammonium, nitrate, or dinitrogen as the nitrogen source.

  17. The Effects of the Toxic Cyanobacterium Limnothrix (Strain AC0243) on Bufo marinus Larvae

    PubMed Central

    Daniels, Olivia; Fabbro, Larelle; Makiela, Sandrine

    2014-01-01

    Limnothrix (strain AC0243) is a cyanobacterium, which has only recently been identified as toxin producing. Under laboratory conditions, Bufo marinus larvae were exposed to 100,000 cells mL−1 of Limnothrix (strain AC0243) live cultures for seven days. Histological examinations were conducted post mortem and revealed damage to the notochord, eyes, brain, liver, kidney, pancreas, gastrointestinal tract, and heart. The histopathological results highlight the toxicological impact of this strain, particularly during developmental stages. Toxicological similarities to β-N-Methylamino-l-alanine are discussed. PMID:24662524

  18. New anabaenopeptins, potent carboxypeptidase-A inhibitors from the cyanobacterium Aphanizomenon flos-aquae.

    PubMed

    Murakami, M; Suzuki, S; Itou, Y; Kodani, S; Ishida, K

    2000-09-01

    Anabaenopeptins I (1) and J (2), two new ureido bond-containing cyclic peptides, were isolated from the cultured cyanobacterium Aphanizomenon flos-aquae (NIES-81) as potent carboxypeptidase-A (CPA) inhibitors. The gross structures of 1 and 2 were established by spectroscopic analysis, including the 2D NMR techniques. The absolute configurations of 1 and 2 were determined by spectral and chemical methods. Anabaenopeptins I and J inhibited CPA with IC(50) values of 5.2 and 7.6 ng/mL, respectively.

  19. The amt Gene Cluster of the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120 ▿

    PubMed Central

    Paz-Yepes, Javier; Merino-Puerto, Victoria; Herrero, Antonia; Flores, Enrique

    2008-01-01

    The genome of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 bears a gene cluster including three amt genes that, based on homology of their protein products, we designate amt4, amt1, and amtB. Expression of the three genes took place upon ammonium withdrawal in combined nitrogen-free medium and was NtcA dependent. The genes were transcribed independently, but an amt4-amt1 dicistronic transcript was also produced, and expression was highest for the amt1 gene. A mutant with the whole amt region removed could grow under laboratory conditions using ammonium, nitrate, or dinitrogen as the nitrogen source. PMID:18689479

  20. Acetylome analysis reveals the involvement of lysine acetylation in photosynthesis and carbon metabolism in the model cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Mo, Ran; Yang, Mingkun; Chen, Zhuo; Cheng, Zhongyi; Yi, Xingling; Li, Chongyang; He, Chenliu; Xiong, Qian; Chen, Hui; Wang, Qiang; Ge, Feng

    2015-02-06

    Cyanobacteria are the oldest known life form inhabiting Earth and the only prokaryotes capable of performing oxygenic photosynthesis. Synechocystis sp. PCC 6803 (Synechocystis) is a model cyanobacterium used extensively in research on photosynthesis and environmental adaptation. Posttranslational protein modification by lysine acetylation plays a critical regulatory role in both eukaryotes and prokaryotes; however, its extent and function in cyanobacteria remain unexplored. Herein, we performed a global acetylome analysis on Synechocystis through peptide prefractionation, antibody enrichment, and high accuracy LC-MS/MS analysis; identified 776 acetylation sites on 513 acetylated proteins; and functionally categorized them into an interaction map showing their involvement in various biological processes. Consistent with previous reports, a large fraction of the acetylation sites are present on proteins involved in cellular metabolism. Interestingly, for the first time, many proteins involved in photosynthesis, including the subunits of phycocyanin (CpcA, CpcB, CpcC, and CpcG) and allophycocyanin (ApcA, ApcB, ApcD, ApcE, and ApcF), were found to be lysine acetylated, suggesting that lysine acetylation may play regulatory roles in the photosynthesis process. Six identified acetylated proteins associated with photosynthesis and carbon metabolism were further validated by immunoprecipitation and Western blotting. Our data provide the first global survey of lysine acetylation in cyanobacteria and reveal previously unappreciated roles of lysine acetylation in the regulation of photosynthesis. The provided data set may serve as an important resource for the functional analysis of lysine acetylation in cyanobacteria and facilitate the elucidation of the entire metabolic networks and photosynthesis process in this model cyanobacterium.

  1. Handbook of legumes of world economic importance

    SciTech Connect

    Duke, J.A.

    1981-01-01

    Treatments by 65 contributing authors are presented for some 150 species of Leguminosae (including major tree and shrub species) with information on: uses, folk medicine, chemistry, 'germplasm'; ecology; cultivation/harvesting/yields; and biotic factors affecting the species.

  2. Dolomite: occurrence, evolution and economically important associations

    NASA Astrophysics Data System (ADS)

    Warren, John

    2000-11-01

    Dolomite is not a simple mineral; it can form as a primary precipitate, a diagenetic replacement, or as a hydrothermal/metamorphic phase, all that it requires is permeability, a mechanism that facilitates fluid flow, and a sufficient supply of magnesium. Dolomite can form in lakes, on or beneath the shallow seafloor, in zones of brine reflux, and in early to late burial settings. It may form from seawater, from continental waters, from the mixing of basinal brines, the mixing of hypersaline brine with seawater, or the mixing of seawater with meteoric water, or via the cooling of basinal brines. Bacterial metabolism may aid the process of precipitation in settings where sulfate-reducing species flourish and microbial action may control primary precipitation in some hypersaline anoxic lake settings. Dolomite is a metastable mineral, early formed crystals can be replaced by later more stable phases with such replacements repeated a number of times during burial and metamorphism. Each new phase is formed by the partial or complete dissolution of an earlier dolomite. This continual re-equilibration during burial detracts from the ability of trace elements to indicate depositional conditions and resets the oxygen isotope signature of the dolomite at progressively higher temperatures. Because subsurface dolomite evolves via dissolution and reprecipitation, a bed of dolomite can retain or create porosity and permeability to much greater burial depths and into higher temperature realms than a limestone counterpart. Dolomitization also creates new crystals, with new rhomb growth following the dissolution of less stable precursors. Repetition of this process, without complete pore cementation, can generate intercrystalline porosity a number of times in the rock's burial history. Intercrystalline porosity is a highly interconnected style of porosity that gives dolomite reservoirs their good fluid storage capacity and efficient drainage. The fact that many dolomite reservoirs formed via brine reflux means that they sit beneath an evaporite seal in both platform and basinwide evaporite settings. The same association of evaporites (sulfate source) and entrained hydrocarbons means that burial conditions are also suitable for thermochemical sulfate reduction and the precipitation of base metals. This tends to occur at higher temperatures (>60°C-80°C) and so the resulting dolomites tend to be ferroan and consist of saddle-shaped crystals.

  3. Comparative genomics reveals diversified CRISPR-Cas systems of globally distributed Microcystis aeruginosa, a freshwater bloom-forming cyanobacterium

    PubMed Central

    Yang, Chen; Lin, Feibi; Li, Qi; Li, Tao; Zhao, Jindong

    2015-01-01

    Microcystis aeruginosa is one of the most common and dominant bloom-forming cyanobacteria in freshwater lakes around the world. Microcystis cells can produce toxic secondary metabolites, such as microcystins, which are harmful to human health. Two M. aeruginosa strains were isolated from two highly eutrophic lakes in China and their genomes were sequenced. Comparative genomic analysis was performed with the 12 other available M. aeruginosa genomes and closely related unicellular cyanobacterium. Each genome of M. aeruginosa containing at least one clustered regularly interspaced short palindromic repeat (CRISPR) locus and total 71 loci were identified, suggesting it is ubiquitous in M. aeruginosa genomes. In addition to the previously reported subtype I-D cas gene sets, three CAS subtypes I-A, III-A and III-B were identified and characterized in this study. Seven types of CRISPR direct repeat have close association with CAS subtype, confirming that different and specific secondary structures of CRISPR repeats are important for the recognition, binding and process of corresponding cas gene sets. Homology search of the CRISPR spacer sequences provides a history of not only resistance to bacteriophages and plasmids known to be associated with M. aeruginosa, but also the ability to target much more exogenous genetic material in the natural environment. These adaptive and heritable defense mechanisms play a vital role in keeping genomic stability and self-maintenance by restriction of horizontal gene transfer. Maintaining genomic stability and modulating genomic plasticity are both important evolutionary strategies for M. aeruginosa in adaptation and survival in various habitats. PMID:26029174

  4. Comparative genomics reveals diversified CRISPR-Cas systems of globally distributed Microcystis aeruginosa, a freshwater bloom-forming cyanobacterium.

    PubMed

    Yang, Chen; Lin, Feibi; Li, Qi; Li, Tao; Zhao, Jindong

    2015-01-01

    Microcystis aeruginosa is one of the most common and dominant bloom-forming cyanobacteria in freshwater lakes around the world. Microcystis cells can produce toxic secondary metabolites, such as microcystins, which are harmful to human health. Two M. aeruginosa strains were isolated from two highly eutrophic lakes in China and their genomes were sequenced. Comparative genomic analysis was performed with the 12 other available M. aeruginosa genomes and closely related unicellular cyanobacterium. Each genome of M. aeruginosa containing at least one clustered regularly interspaced short palindromic repeat (CRISPR) locus and total 71 loci were identified, suggesting it is ubiquitous in M. aeruginosa genomes. In addition to the previously reported subtype I-D cas gene sets, three CAS subtypes I-A, III-A and III-B were identified and characterized in this study. Seven types of CRISPR direct repeat have close association with CAS subtype, confirming that different and specific secondary structures of CRISPR repeats are important for the recognition, binding and process of corresponding cas gene sets. Homology search of the CRISPR spacer sequences provides a history of not only resistance to bacteriophages and plasmids known to be associated with M. aeruginosa, but also the ability to target much more exogenous genetic material in the natural environment. These adaptive and heritable defense mechanisms play a vital role in keeping genomic stability and self-maintenance by restriction of horizontal gene transfer. Maintaining genomic stability and modulating genomic plasticity are both important evolutionary strategies for M. aeruginosa in adaptation and survival in various habitats.

  5. Growth of Cyanobacterium aponinum influenced by increasing salt concentrations and temperature.

    PubMed

    Winckelmann, Dominik; Bleeke, Franziska; Bergmann, Peter; Klöck, Gerd

    2015-06-01

    The increasing requirement of food neutral biofuels demands the detection of alternative sources. The use of non-arable land and waste water streams is widely discussed in this regard. A Cyanobacterium was isolated on the area of a possible algae production side near a water treatment plant in the arid desert region al-Wusta. It was identified as Cyanobacterium aponinum PB1 and is a possible lipid source. To determine its suitability of a production process using this organism, a set of laboratory experiments were performed. Its growth behavior was examined in regard to high temperatures and increasing NaCl concentrations. A productivity of 0.1 g L(-1) per day was measured at an alga density below 0.75 g L(-1). C. aponinum PB1 showed no sign of altered growth behavior in media containing 70 g L(-1) NaCl or less. Detection of a negative effect of NaCl on the growth using Pulse-Amplitude-Modulation chlorophyll fluorescence analysis was not more sensitive than optical density measurement.

  6. Collapsing aged culture of the cyanobacterium Synechococcus elongatus produces compound(s) toxic to photosynthetic organisms.

    PubMed

    Cohen, Assaf; Sendersky, Eleonora; Carmeli, Shmuel; Schwarz, Rakefet

    2014-01-01

    Phytoplankton mortality allows effective nutrient cycling, and thus plays a pivotal role in driving biogeochemical cycles. A growing body of literature demonstrates the involvement of regulated death programs in the abrupt collapse of phytoplankton populations, and particularly implicates processes that exhibit characteristics of metazoan programmed cell death. Here, we report that the cell-free, extracellular fluid (conditioned medium) of a collapsing aged culture of the cyanobacterium Synechococcus elongatus is toxic to exponentially growing cells of this cyanobacterium, as well as to a large variety of photosynthetic organisms, but not to eubacteria. The toxic effect, which is light-dependent, involves oxidative stress, as suggested by damage alleviation by antioxidants, and the very high sensitivity of a catalase-mutant to the conditioned medium. At relatively high cell densities, S. elongatus cells survived the deleterious effect of conditioned medium in a process that required de novo protein synthesis. Application of conditioned medium from a collapsing culture caused severe pigment bleaching not only in S. elongatus cells, but also resulted in bleaching of pigments in a cell free extract. The latter observation indicates that the elicited damage is a direct effect that does not require an intact cell, and therefore, is mechanistically different from the metazoan-like programmed cell death described for phytoplankton. We suggest that S. elongatus in aged cultures are triggered to produce a toxic compound, and thus, this process may be envisaged as a novel regulated death program.

  7. Dynamics of the Toxin Cylindrospermopsin and the Cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum in a Mediterranean Eutrophic Reservoir

    PubMed Central

    Fadel, Ali; Atoui, Ali; Lemaire, Bruno J.; Vinçon-Leite, Brigitte; Slim, Kamal

    2014-01-01

    Chrysosporum ovalisporum is a cylindrospermopsin toxin producing cyanobacterium that was reported in several lakes and reservoirs. Its growth dynamics and toxin distribution in field remain largely undocumented. Chrysosporum ovalisporum was reported in 2009 in Karaoun Reservoir, Lebanon. We investigated the factors controlling the occurrence of this cyanobacterium and vertical distribution of cylindrospermopsin in Karaoun Reservoir. We conducted bi-weekly sampling campaigns between May 2012 and August 2013. Results showed that Chrysosporum ovalisporum is an ecologically plastic species that was observed in all seasons. Unlike the high temperatures, above 26 °C, which is associated with blooms of Chrysosporum ovalisporum in Lakes Kinneret (Israel), Lisimachia and Trichonis (Greece) and Arcos Reservoir (Spain), Chrysosporum ovalisporum in Karaoun Reservoir bloomed in October 2012 at a water temperature of 22 °C during weak stratification. Cylindrospermopsin was detected in almost all water samples even when Chrysosporum ovalisporum was not detected. Chrysosporum ovalisporum biovolumes and cylindrospermopsin concentrations were not correlated (n = 31, r2 = −0.05). Cylindrospermopsin reached a maximum concentration of 1.7 µg L−1. The vertical profiles of toxin concentrations suggested its possible degradation or sedimentation resulting in its disappearance from the water column. The field growth conditions of Chrysosporum ovalisporum in this study revealed that it can bloom at the subsurface water temperature of 22 °C increasing the risk of its development and expansion in lakes located in temperate climate regions. PMID:25354130

  8. Collapsing Aged Culture of the Cyanobacterium Synechococcus elongatus Produces Compound(s) Toxic to Photosynthetic Organisms

    PubMed Central

    Cohen, Assaf; Sendersky, Eleonora; Carmeli, Shmuel; Schwarz, Rakefet

    2014-01-01

    Phytoplankton mortality allows effective nutrient cycling, and thus plays a pivotal role in driving biogeochemical cycles. A growing body of literature demonstrates the involvement of regulated death programs in the abrupt collapse of phytoplankton populations, and particularly implicates processes that exhibit characteristics of metazoan programmed cell death. Here, we report that the cell-free, extracellular fluid (conditioned medium) of a collapsing aged culture of the cyanobacterium Synechococcus elongatus is toxic to exponentially growing cells of this cyanobacterium, as well as to a large variety of photosynthetic organisms, but not to eubacteria. The toxic effect, which is light-dependent, involves oxidative stress, as suggested by damage alleviation by antioxidants, and the very high sensitivity of a catalase-mutant to the conditioned medium. At relatively high cell densities, S. elongatus cells survived the deleterious effect of conditioned medium in a process that required de novo protein synthesis. Application of conditioned medium from a collapsing culture caused severe pigment bleaching not only in S. elongatus cells, but also resulted in bleaching of pigments in a cell free extract. The latter observation indicates that the elicited damage is a direct effect that does not require an intact cell, and therefore, is mechanistically different from the metazoan-like programmed cell death described for phytoplankton. We suggest that S. elongatus in aged cultures are triggered to produce a toxic compound, and thus, this process may be envisaged as a novel regulated death program. PMID:24959874

  9. Evaluation of the capacity of the cyanobacterium Microcystis novacekii to remove atrazine from a culture medium.

    PubMed

    Campos, Marcela M C; Faria, Vanessa H F; Teodoro, Taciane S; Barbosa, Francisco A R; Magalhães, Sérgia M S

    2013-01-01

    The bioaccumulation of atrazine and its toxicity were evaluated for the cyanobacterium Microcystis novacekii. Cyanobacterial cultures were grown in WC culture medium with atrazine at 50, 250 and 500 μg L(-1). After 96 hours of exposure, 27.2% of the atrazine had been removed from the culture supernatant. Spontaneous degradation was found to be insignificant (< 9% at 500 μg L(-1)), indicating a high efficiency for the bioaccumulation of atrazine by M. novacekii. There were no atrazine metabolites detected in the culture medium at any of the doses studied. The acute toxicity (EC(50)) of atrazine to the cyanobacterium was 4.2 mg L(-1) at 96 hours demonstrating the potential for M. novacekii to tolerate high concentrations of this herbicide in fresh water environments. The ability of M. novacekii to remove atrazine combined with its tolerance of the pesticide toxicity showed in this study makes it a potential biological resource for the restoration of contaminated surface waters. These findings support continued studies of the role of M. novacekii in the bioremediation of fresh water environments polluted by atrazine.

  10. Unique Thylakoid Membrane Architecture of a Unicellular N2-Fixing Cyanobacterium Revealed by Electron Tomography

    SciTech Connect

    Liberton, Michelle L.; Austin, Jotham R.; Berg, R. H.; Pakrasi, Himadri B.

    2011-04-01

    Cyanobacteria, descendants of the endosymbiont that gave rise to modern-day chloroplasts, are vital contributors to global biological energy conversion processes. A thorough understanding of the physiology of cyanobacteria requires detailed knowledge of these organisms at the level of cellular architecture and organization. In these prokaryotes, the large membrane protein complexes of the photosynthetic and respiratory electron transport chains function in the intracellular thylakoid membranes. Like plants, the architecture of the thylakoid membranes in cyanobacteria has direct impact on cellular bioenergetics, protein transport, and molecular trafficking. However, whole-cell thylakoid organization in cyanobacteria is not well understood. Here we present, by using electron tomography, an in-depth analysis of the architecture of the thylakoid membranes in a unicellular cyanobacterium, Cyanothece sp. ATCC 51142. Based on the results of three-dimensional tomographic reconstructions of near-entire cells, we determined that the thylakoids in Cyanothece 51142 form a dense and complex network that extends throughout the entire cell. This thylakoid membrane network is formed from the branching and splitting of membranes and encloses a single lumenal space. The entire thylakoid network spirals as a peripheral ring of membranes around the cell, an organization that has not previously been described in a cyanobacterium. Within the thylakoid membrane network are areas of quasi-helical arrangement with similarities to the thylakoid membrane system in chloroplasts. This cyanobacterial thylakoid arrangement is an efficient means of packing a large volume of membranes in the cell while optimizing intracellular transport and trafficking.

  11. Unique thylakoid membrane architecture of a unicellular N2-fixing cyanobacterium revealed by electron tomography

    SciTech Connect

    Liberton, Michelle; Austin II, Jotham R; Berg, R. Howard; Pakrasi, Himadri B

    2011-04-01

    Cyanobacteria, descendants of the endosymbiont that gave rise to modern-day chloroplasts, are vital contributors to global biological energy conversion processes. A thorough understanding of the physiology of cyanobacteria requires detailed knowledge of these organisms at the level of cellular architecture and organization. In these prokaryotes, the large membrane protein complexes of the photosynthetic and respiratory electron transport chains function in the intracellular thylakoid membranes. Like plants, the architecture of the thylakoid membranes in cyanobacteria has direct impact on cellular bioenergetics, protein transport, and molecular trafficking. However, whole-cell thylakoid organization in cyanobacteria is not well understood. Here we present, by using electron tomography, an in-depth analysis of the architecture of the thylakoid membranes in a unicellular cyanobacterium, Cyanothece sp. ATCC 51142. Based on the results of three-dimensional tomographic reconstructions of near-entire cells, we determined that the thylakoids in Cyanothece 51142 form a dense and complex network that extends throughout the entire cell. This thylakoid membrane network is formed from the branching and splitting of membranes and encloses a single lumenal space. The entire thylakoid network spirals as a peripheral ring of membranes around the cell, an organization that has not previously been described in a cyanobacterium. Within the thylakoid membrane network are areas of quasi-helical arrangement with similarities to the thylakoid membrane system in chloroplasts. This cyanobacterial thylakoid arrangement is an efficient means of packing a large volume of membranes in the cell while optimizing intracellular transport and trafficking.

  12. Aluminum Effects on Uptake and Metabolism of Phosphorus by the Cyanobacterium Anabaena cylindrica

    PubMed Central

    Pettersson, Annette; Hällbom, Lars; Bergman, Birgitta

    1988-01-01

    Aluminum severely affects the growth of the cyanobacterium Anabaena cylindrica and induces symptoms indicating phosphorus starvation. Preor post-treating the cells with high (90 micromolar) phosphorus reduces the toxicity of aluminum compared to cells receiving a lower orthophosphate concentration. In this study aluminum (ranging from 9 to 36 micromolar) and phosphorus concentrations were chosen so that the precipitation of insoluble AIPO4 never exceeded 10% of the total phosphate concentration. The uptake of 32P-phosphorus is not disturbed by aluminum either at high (100 micromolar) or low (10 micromolar) concentrations of phosphate. Also, the rapid accumulation of polyphosphate granules in cells exposed to aluminum indicates that the incorporation of phosphate is not disturbed. However, a significant decrease in the mobilization of the polyphosphates is observed, as is a lowered activity of the enzyme acid phosphatase, in aluminum treated cells. We conclude that aluminum acts on the intracellular metabolism of phosphate, which eventually leads to phosphorus starvation rather than on its uptake in the cyanobacterium A. cylindrica. PMID:16665849

  13. The Effect of Small Scale Turbulence on the Physiology of Microcystis aeruginosa cyanobacterium

    NASA Astrophysics Data System (ADS)

    Wilkinson, Anne; Hondzo, Miki; Guala, Michele

    2014-11-01

    Microcystis aeruginosa is a single-celled blue-green alga, or cyanobacterium, that is responsible for poor water quality and microcystin production, which in high concentrations can be harmful to humans and animals. These harmful effects arise during cyanobacterium blooms. Blooms occur mainly in the summer when the algae grow uncontrollably and bond together to form colonies which accumulate on the surface of freshwater ecosystems. The relationship between fluid motion generated by wind and internal waves in stratified aquatic ecosystems and Microcystis can help explain the mechanisms of such blooms. We investigated the effect of small scale fluid motion on the physiology of Microcystis in a reactor with two underwater speakers. Different turbulent intensities were achieved by systematically changing the input signal frequency (30-50 Hz) and magnitude (0.1-0.2V) to the speakers. The role of turbulence is quantified by relating energy dissipation rates with the cell number, chlorophyll amount, dissolved oxygen production/uptake, and pH. The results suggest that turbulence mediates the physiology of Microcystis. The findings could be instrumental in designing restoration strategies that can minimize Microcystis blooms. This work was supported by the NSF Graduate Research Fellowship and University of Minnesota start-up funding.

  14. The Plasma Membrane of the Cyanobacterium Gloeobacter violaceus Contains Segregated Bioenergetic Domains[C][W

    PubMed Central

    Rexroth, Sascha; Mullineaux, Conrad W.; Ellinger, Dorothea; Sendtko, Esther; Rögner, Matthias; Koenig, Friederike

    2011-01-01

    The light reactions of oxygenic photosynthesis almost invariably take place in the thylakoid membranes, a highly specialized internal membrane system located in the stroma of chloroplasts and the cytoplasm of cyanobacteria. The only known exception is the primordial cyanobacterium Gloeobacter violaceus, which evolved before the appearance of thylakoids and harbors the photosynthetic complexes in the plasma membrane. Thus, studies on G. violaceus not only shed light on the evolutionary origin and the functional advantages of thylakoid membranes but also might include insights regarding thylakoid formation during chloroplast differentiation. Based on biochemical isolation and direct in vivo characterization, we report here structural and functional domains in the cytoplasmic membrane of a cyanobacterium. Although G. violaceus has no internal membranes, it does have localized domains with apparently specialized functions in its plasma membrane, in which both the photosynthetic and the respiratory complexes are concentrated. These bioenergetic domains can be visualized by confocal microscopy, and they can be isolated by a simple procedure. Proteomic analysis of these domains indicates their physiological function and suggests a protein sorting mechanism via interaction with membrane-intrinsic terpenoids. Based on these results, we propose specialized domains in the plasma membrane as evolutionary precursors of thylakoids. PMID:21642550

  15. Unique thylakoid membrane architecture of a unicellular N2-fixing cyanobacterium revealed by electron tomography.

    PubMed

    Liberton, Michelle; Austin, Jotham R; Berg, R Howard; Pakrasi, Himadri B

    2011-04-01

    Cyanobacteria, descendants of the endosymbiont that gave rise to modern-day chloroplasts, are vital contributors to global biological energy conversion processes. A thorough understanding of the physiology of cyanobacteria requires detailed knowledge of these organisms at the level of cellular architecture and organization. In these prokaryotes, the large membrane protein complexes of the photosynthetic and respiratory electron transport chains function in the intracellular thylakoid membranes. Like plants, the architecture of the thylakoid membranes in cyanobacteria has direct impact on cellular bioenergetics, protein transport, and molecular trafficking. However, whole-cell thylakoid organization in cyanobacteria is not well understood. Here we present, by using electron tomography, an in-depth analysis of the architecture of the thylakoid membranes in a unicellular cyanobacterium, Cyanothece sp. ATCC 51142. Based on the results of three-dimensional tomographic reconstructions of near-entire cells, we determined that the thylakoids in Cyanothece 51142 form a dense and complex network that extends throughout the entire cell. This thylakoid membrane network is formed from the branching and splitting of membranes and encloses a single lumenal space. The entire thylakoid network spirals as a peripheral ring of membranes around the cell, an organization that has not previously been described in a cyanobacterium. Within the thylakoid membrane network are areas of quasi-helical arrangement with similarities to the thylakoid membrane system in chloroplasts. This cyanobacterial thylakoid arrangement is an efficient means of packing a large volume of membranes in the cell while optimizing intracellular transport and trafficking.

  16. Physiological conditions for nitrogen fixation in a unicellular marine cyanobacterium, Synechococcus sp. strain SF1.

    PubMed Central

    Spiller, H; Shanmugam, K T

    1987-01-01

    A marine, unicellular, nitrogen-fixing cyanobacterium was isolated from the blades of a brown alga, Sargassum fluitans. This unicellular cyanobacterium, identified as Synechococcus sp. strain SF1, is capable of photoautotrophic growth with bicarbonate as the sole carbon source and dinitrogen as the sole nitrogen source. Among the organic carbon compounds tested, glucose and sucrose supported growth. Of the nitrogen compounds tested, with bicarbonate serving as the carbon source, both ammonia and nitrate produced the highest growth rates. Most amino acids failed to support growth when present as sole sources of nitrogen. Nitrogenase activity in Synechococcus sp. strain SF1 was induced after depletion of ammonia from the medium. This activity required the photosynthetic utilization of bicarbonate, but pyruvate and hydrogen gas were also effective sources of reductant for nitrogenase activity. Glucose, fructose, and sucrose also supported nitrogenase activity but to a lesser extent. Optimum light intensity for nitrogenase activity was found to be 70 microE/m2 per s, while the optimum oxygen concentration in the gas phase for nitrogenase activity was about 1%. A hydrogenase activity was coinduced with nitrogenase activity. It is proposed that this light- and oxygen-insensitive hydrogenase functions in recycling the hydrogen produced by nitrogenase under microaerobic conditions. PMID:3119563

  17. The production of the sesquiterpene β-caryophyllene in a transgenic strain of the cyanobacterium Synechocystis.

    PubMed

    Reinsvold, Robert E; Jinkerson, Robert E; Radakovits, Randor; Posewitz, Matthew C; Basu, Chhandak

    2011-05-15

    The plant secondary metabolite, β-caryophyllene, is a ubiquitous component of many plant resins that has traditionally been used in the cosmetics industry to provide a woody, spicy aroma to cosmetics and perfumes. Clinical studies have shown it to be potentially effective as an antibiotic, anesthetic, and anti-inflammatory agent. Additionally, there is significant interest in engineering phototrophic microorganisms with sesquiterpene synthase genes for the production of biofuels. Currently, the isolation of β-caryophyllene relies on purification methods from oleoresins extracted from large amounts of plant material. An engineered cyanobacterium platform that produces β-caryophyllene may provide a more sustainable and controllable means of production. To this end, the β-caryophyllene synthase gene (QHS1) from Artemisia annua was stably inserted, via double homologous recombination, into the genome of the cyanobacterium Synechocystis sp. strain PCC6803. Gene insertion into Synechocystis was confirmed through PCR assays and sequencing reactions. Transcription and expression of QHS1 were confirmed using RT-PCR, and synthesis of β-caryophyllene was confirmed in the transgenic strain using GC-FID and GC-MS analysis. Copyright © 2010 Elsevier GmbH. All rights reserved.

  18. Discovery of an Endosymbiotic Nitrogen-Fixing Cyanobacterium UCYN-A in Braarudosphaera bigelowii (Prymnesiophyceae)

    PubMed Central

    Hagino, Kyoko; Onuma, Ryo; Kawachi, Masanobu; Horiguchi, Takeo

    2013-01-01

    Braarudosphaera bigelowii (Prymnesiophyceae) is a coastal coccolithophore with a long fossil record, extending back to the late Cretaceous (ca. 100 Ma). A recent study revealed close phylogenetic relationships between B. bigelowii, Chrysochromulina parkeae (Prymnesiophyceae), and a prymnesiophyte that forms a symbiotic association with the nitrogen-fixing cyanobacterium UCYN-A. In order to further examine these relationships, we conducted transmission electron microscopic and molecular phylogenetic studies of B. bigelowii. TEM studies showed that, in addition to organelles, such as the nucleus, chloroplasts and mitochondria, B. bigelowii contains one or two spheroid bodies with internal lamellae. In the 18S rDNA tree of the Prymnesiophyceae, C. parkeae fell within the B. bigelowii clade, and was close to B. bigelowii Genotype III (99.89% similarity). Plastid 16S rDNA sequences obtained from B. bigelowii were close to the unidentified sequences from the oligotrophic SE Pacific Ocean (e.g. HM133411) (99.86% similarity). Bacterial16S rDNA sequences obtained from B. bigelowii were identical to the UCYN-A sequence AY621693 from Arabian Sea, and fell in the UCYN-A clade. From these results, we suggest that; 1) C. parkeae is the alternate life cycle stage of B. bigelowii sensu stricto or that of a sibling species of B. bigelowii, and 2) the spheroid body of B. bigelowii originated from endosymbiosis of the nitrogen-fixing cyanobacterium UCYN-A. PMID:24324722

  19. Dynamics of the toxin cylindrospermopsin and the cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum in a Mediterranean eutrophic reservoir.

    PubMed

    Fadel, Ali; Atoui, Ali; Lemaire, Bruno J; Vinçon-Leite, Brigitte; Slim, Kamal

    2014-10-28

    Chrysosporum ovalisporum is a cylindrospermopsin toxin producing cyanobacterium that was reported in several lakes and reservoirs. Its growth dynamics and toxin distribution in field remain largely undocumented. Chrysosporum ovalisporum was reported in 2009 in Karaoun Reservoir, Lebanon. We investigated the factors controlling the occurrence of this cyanobacterium and vertical distribution of cylindrospermopsin in Karaoun Reservoir. We conducted bi-weekly sampling campaigns between May 2012 and August 2013. Results showed that Chrysosporum ovalisporum is an ecologically plastic species that was observed in all seasons. Unlike the high temperatures, above 26 °C, which is associated with blooms of Chrysosporum ovalisporum in Lakes Kinneret (Israel), Lisimachia and Trichonis (Greece) and Arcos Reservoir (Spain), Chrysosporum ovalisporum in Karaoun Reservoir bloomed in October 2012 at a water temperature of 22 °C during weak stratification. Cylindrospermopsin was detected in almost all water samples even when Chrysosporum ovalisporum was not detected. Chrysosporum ovalisporum biovolumes and cylindrospermopsin concentrations were not correlated (n = 31, r² = -0.05). Cylindrospermopsin reached a maximum concentration of 1.7 µg L⁻¹. The vertical profiles of toxin concentrations suggested its possible degradation or sedimentation resulting in its disappearance from the water column. The field growth conditions of Chrysosporum ovalisporum in this study revealed that it can bloom at the subsurface water temperature of 22 °C increasing the risk of its development and expansion in lakes located in temperate climate regions.

  20. Novel thermostable glycosidases in the extracellular matrix of the terrestrial cyanobacterium Nostoc commune.

    PubMed

    Morsy, Fatthy Mohamed; Kuzuha, Satomi; Takani, Yayoi; Sakamoto, Toshio

    2008-10-01

    The cyanobacterium Nostoc commune is adapted to the terrestrial environment and forms a visible colony in which the cells are embedded in extracellular polysaccharides (EPSs), which play a crucial role in the extreme desiccation tolerance of this organism. When natural colonies were immersed in water, degradation of the colonies occurred within 2 days and N. commune cells were released into the water. The activities that hydrolyze glycoside bonds in various N. commune fractions were examined using artificial nitrophenyl-linked sugars as substrates. A beta-D-glucosidase purified from the water-soluble fraction was resistant to 20 min of boiling. The beta-D-glucosidase, with a molecular mass of 20 kDa, was identified as a cyanobacterial fasciclin protein based on its N-terminal amino-acid sequence. The 36-kDa major protein in the water-soluble fraction was purified, and the N-terminal amino-acid sequence of the protein was found to be identical to that of the water-stress protein (WspA) of N. commune. This WspA protein also showed heat-resistant beta-D-galactosidase activity. The fasciclin protein and WspA in the extracellular matrix may play a role in the hydrolysis of the EPSs surrounding the cells, possibly as an aid in the dispersal of cells, thus expanding the colonies of this cyanobacterium.

  1. Crucial Role of Extracellular Polysaccharides in Desiccation and Freezing Tolerance in the Terrestrial Cyanobacterium Nostoc commune

    PubMed Central

    Tamaru, Yoshiyuki; Takani, Yayoi; Yoshida, Takayuki; Sakamoto, Toshio

    2005-01-01

    The cyanobacterium Nostoc commune is adapted to the terrestrial environment and has a cosmopolitan distribution. In this study, the role of extracellular polysaccharides (EPS) in the desiccation tolerance of photosynthesis in N. commune was examined. Although photosynthetic O2 evolution was not detected in desiccated colonies, the ability of the cells to evolve O2 rapidly recovered after rehydration. The air-dried colonies contained approximately 10% (wt/wt) water, and field-isolated, natural colonies with EPS were highly water absorbent and were rapidly hydrated by atmospheric moisture. The cells embedded in EPS in Nostoc colonies were highly desiccation tolerant, and O2 evolution was not damaged by air drying. Although N. commune was determined to be a mesophilic cyanobacterium, the cells with EPS were heat tolerant in a desiccated state. EPS could be removed from cells by homogenizing colonies with a blender and filtering with coarse filter paper. This treatment to remove EPS did not damage Nostoc cells or their ability to evolve O2, but O2 evolution was significantly damaged by desiccation treatment of the EPS-depleted cells. Similar to the EPS-depleted cells, the laboratory culture strain KU002 had only small amount of EPS and was highly sensitive to desiccation. In the EPS-depleted cells, O2 evolution was also sensitive to freeze-thaw treatment. These results strongly suggest that EPS of N. commune is crucial for the stress tolerance of photosynthesis during desiccation and during freezing and thawing. PMID:16269775

  2. Antiherpetic efficacy of aqueous extracts of the cyanobacterium Arthrospira fusiformis from Chad.

    PubMed

    Sharaf, M; Amara, A; Aboul-Enein, A; Helmi, S; Ballot, A; Schnitzler, P

    2013-05-01

    Natural substances offer interesting pharmacological perspectives for antiviral drug development with regard to broad spectrum antiviral properties and novel modes of action. Drugs currently used to treat cutaneous or genital herpetic infections are effective in limiting disease, but the emergence of drug-resistant viruses in immunocompromised individuals can be problematic. A nontoxic cyanobacterium Arthrospira strain from Chad has been characterized by sequence analysis of the intergenic spacer region of the phycocyanin gene. This cyanobacterium was identified as Arthrospira fusiformis by phylogenetic tree analysis. The antiherpetic activity of crude aqueous extracts from the Chad A. fusiformis isolate was determined. Antiviral efficacy against herpes simplex virus of cold water extract, hot water extract and phosphate buffer extract was assessed in plaque reduction assays and their mode of antiherpetic action was analysed. In virus suspension assays, cold water extract, hot water extract and phosphate buffer extract inhibited virus infectivity by 54.9%, 64.6%, and 99.8%, respectively, in a dose-dependent manner. The mode of antiviral action was determined by addition of cyanobacterial extracts separately at different time periods during the viral infection cycle. Extracts of A. fusiformis strain clearly inhibited herpesvirus multiplication before and during virus infection of host cells. The phosphate buffer extract of the A. fusiformis strain affected free herpes simplex virus prior to infection of host cells and inhibited intracellular viral replication. It is concluded, that Arthrospira compounds warrant further investigation to examine their potential role in the treatment of herpetic infections.

  3. Allelopathic effects of the toxic cyanobacterium Microcystis aeruginosa on duckweed, Lemna gibba L.

    PubMed

    LeBlanc, Susan; Pick, Frances R; Aranda-Rodriguez, Rocio

    2005-02-01

    Cyanotoxins are a group of compounds produced by cyanobacteria that can have severe physiological effects on other organisms, including humans. The potential allelopathic effects of Microcystis aeruginosa, a toxic cyanobacterium, on the duckweed plant, Lemna gibba L., were examined using three experimental methods: (1) a series of toxicity bioassays, (2) evaluation of toxin production by M. aeruginosa in the direct and indirect presence of L. gibba, and (3) inhibition of oxygen evolution in photosynthesis. The results showed that, first, there were no clear dose-dependent effects of the microcystin-LR standard or the toxic M. aeruginosa culture filtrate on any of the end points measured in the toxicity bioassays (plant and frond number, dry weight, growth rate, chlorophyll content; one-way ANOVA, p > 0.05). In those cases in which an EC(50) value could be obtained, chlorophyll a was the most sensitive end point, as it had the lowest EC(50) value (14.47 microg/L microcystin-LR) of all the end points. Second, the presence of L. gibba did not result in higher microcystin-LR production in the toxic M. aeruginosa culture. And, last, oxygen evolution was not affected in isolated chloroplasts exposed directly to microcystin-LR. Therefore, microcystins from the toxic cyanobacterium Microcystis aeruginosa do not appear to have an allelopathic effect on the common aquatic macrophyte Lemna gibba. (c) 2005 Wiley Periodicals, Inc.

  4. A Nostoc punctiforme sugar transporter necessary to establish a Cyanobacterium-plant symbiosis.

    PubMed

    Ekman, Martin; Picossi, Silvia; Campbell, Elsie L; Meeks, John C; Flores, Enrique

    2013-04-01

    In cyanobacteria-plant symbioses, the symbiotic nitrogen-fixing cyanobacterium has low photosynthetic activity and is supplemented by sugars provided by the plant partner. Which sugars and cyanobacterial sugar uptake mechanism(s) are involved in the symbiosis, however, is unknown. Mutants of the symbiotically competent, facultatively heterotrophic cyanobacterium Nostoc punctiforme were constructed bearing a neomycin resistance gene cassette replacing genes in a putative sugar transport gene cluster. Results of transport activity assays using (14)C-labeled fructose and glucose and tests of heterotrophic growth with these sugars enabled the identification of an ATP-binding cassette-type transporter for fructose (Frt), a major facilitator permease for glucose (GlcP), and a porin needed for the optimal uptake of both fructose and glucose. Analysis of green fluorescent protein fluorescence in strains of N. punctiforme bearing frt::gfp fusions showed high expression in vegetative cells and akinetes, variable expression in hormogonia, and no expression in heterocysts. The symbiotic efficiency of N. punctiforme sugar transport mutants was investigated by testing their ability to infect a nonvascular plant partner, the hornwort Anthoceros punctatus. Strains that were specifically unable to transport glucose did not infect the plant. These results imply a role for GlcP in establishing symbiosis under the conditions used in this work.

  5. Crucial role of extracellular polysaccharides in desiccation and freezing tolerance in the terrestrial cyanobacterium Nostoc commune.

    PubMed

    Tamaru, Yoshiyuki; Takani, Yayoi; Yoshida, Takayuki; Sakamoto, Toshio

    2005-11-01

    The cyanobacterium Nostoc commune is adapted to the terrestrial environment and has a cosmopolitan distribution. In this study, the role of extracellular polysaccharides (EPS) in the desiccation tolerance of photosynthesis in N. commune was examined. Although photosynthetic O2 evolution was not detected in desiccated colonies, the ability of the cells to evolve O2 rapidly recovered after rehydration. The air-dried colonies contained approximately 10% (wt/wt) water, and field-isolated, natural colonies with EPS were highly water absorbent and were rapidly hydrated by atmospheric moisture. The cells embedded in EPS in Nostoc colonies were highly desiccation tolerant, and O2 evolution was not damaged by air drying. Although N. commune was determined to be a mesophilic cyanobacterium, the cells with EPS were heat tolerant in a desiccated state. EPS could be removed from cells by homogenizing colonies with a blender and filtering with coarse filter paper. This treatment to remove EPS did not damage Nostoc cells or their ability to evolve O2, but O2 evolution was significantly damaged by desiccation treatment of the EPS-depleted cells. Similar to the EPS-depleted cells, the laboratory culture strain KU002 had only small amount of EPS and was highly sensitive to desiccation. In the EPS-depleted cells, O2 evolution was also sensitive to freeze-thaw treatment. These results strongly suggest that EPS of N. commune is crucial for the stress tolerance of photosynthesis during desiccation and during freezing and thawing.

  6. Bouillonamide: A Mixed Polyketide–Peptide Cytotoxin from the Marine Cyanobacterium Moorea bouillonii

    PubMed Central

    Tan, Lik Tong; Okino, Tatsufumi; Gerwick, William H.

    2013-01-01

    The tropical marine cyanobacterium, Moorea bouillonii, has gained recent attention as a rich source of bioactive natural products. Continued chemical investigation of this cyanobacterium, collected from New Britain, Papua New Guinea, yielded a novel cytotoxic cyclic depsipeptide, bouillonamide (1), along with previously reported molecules, ulongamide A and apratoxin A. Planar structure of bouillonamide was established by extensive 1D and 2D NMR experiments, including multi-edited HSQC, TOCSY, HBMC, and ROESY experiments. In addition to the presence of α-amino acid residues, compound 1 contained two unique polyketide-derived moieties, namely a 2-methyl-6-methylamino-hex-5-enoic acid (Mmaha) residue and a unit of 3-methyl-5-hydroxy-heptanoic acid (Mhha). Absolute stereochemistry of the α-amino acid units in bouillonamide was determined mainly by Marfey’s analysis. Compound 1 exhibited mild toxicity with IC50’s of 6.0 µM against the neuron 2a mouse neuroblastoma cells. PMID:23966034

  7. A stable, reusable, and highly active photosynthetic bioreactor by bio-interfacing an individual cyanobacterium with a mesoporous bilayer nanoshell.

    PubMed

    Jiang, Nan; Yang, Xiao-Yu; Deng, Zhao; Wang, Li; Hu, Zhi-Yi; Tian, Ge; Ying, Guo-Liang; Shen, Ling; Zhang, Ming-Xi; Su, Bao-Lian

    2015-05-06

    An individual cyanobacterium cell is interfaced with a nanoporous biohybrid layer within a mesoporous silica layer. The bio-interface acts as an egg membrane for cell protection and growth of outer shell. The resulting bilayer shell provides efficient functions to create a single cell photosynthetic bioreactor with high stability, reusability, and activity.

  8. Genome of the cyanobacterium Microcoleus vaginatus FGP-2, a photosynthetic ecosystem engineer of arid land soil biocrusts worldwide.

    PubMed

    Starkenburg, Shawn R; Reitenga, Krista G; Freitas, Tracey; Johnson, Shannon; Chain, Patrick S G; Garcia-Pichel, Ferran; Kuske, Cheryl R

    2011-09-01

    The filamentous cyanobacterium Microcoleus vaginatusis found in arid land soils worldwide. The genome of M. vaginatus strain FGP-2 allows exploration of genes involved in photosynthesis, desiccation tolerance, alkane production, and other features contributing to this organism's ability to function as a major component of biological soil crusts in arid lands.

  9. Draft Genome Sequence of a Thermophilic Cyanobacterium from the Family Oscillatoriales (Strain MTP1) from the Chalk River, Colorado.

    PubMed

    Hallenbeck, Patrick C; Grogger, Melanie; Mraz, Megan; Veverka, Donald

    2016-02-18

    The draft genome (57.7% GC, 7,647,882 bp) of the novel thermophilic cyanobacterium MTP1 was determined by metagenomics of an enrichment culture. The genome shows that it is in the family Oscillatoriales and encodes multiple heavy metal resistances as well as the capacity to make exopolysaccharides.

  10. Draft Genome Sequence of Leptolyngbya sp. KIOST-1, a Filamentous Cyanobacterium with Biotechnological Potential for Alimentary Purposes.

    PubMed

    Kim, Ji Hyung; Kang, Do-Hyung

    2016-09-15

    Here, we report the draft genome of cyanobacterium Leptolyngbya sp. KIOST-1 isolated from a microalgal culture pond in South Korea. The genome consists of 13 contigs containing 6,320,172 bp, and a total of 5,327 coding sequences were predicted. This genomic information will allow further exploitation of its biotechnological potential for alimentary purposes.

  11. Medium-tech industries may be of greater importance to a local economy than 'High-tech' firms: new methods for measuring the knowledge base of an economic system.

    PubMed

    Dolfsma, Wilfred; Leydesdorff, Loet

    2008-09-01

    In this paper we offer a way to measure the knowledge base of an economy in terms of probabilistic entropy. This measure, we hypothesize, is an indication of the extent to which a system, including the economic system, self-organizes. In a self-organizing system, interactions between dimensions or subsystems will unintentionally give rise to anticipations that are properly aligned. The potential reduction of uncertainty can be measured as negative entropy in the mutual information among three (or more) dimensions. For a knowledge-based economy, three dimensions can be considered as key: the distribution of firm sizes, the geographical locations, and the technological classifications of firms. Based on statistics of these three dimensions and drawing on a unique dataset of all Dutch firms registered with the Chambers of Commerce, we are able to refine well-known empirical findings for the geographical dimension. Counter-intuitive, however, are our empirical findings for the dimension of technology. Knowledge diffusion through medium-tech industry is much more important for a localized economy than knowledge creation in high-tech industry. Knowledge-intensive services tend to uncouple economic activities from the regional dimension.

  12. The importance of social support in the associations between psychological distress and somatic health problems and socio-economic factors among older adults living at home: a cross sectional study

    PubMed Central

    2012-01-01

    Background Little is known of the importance of social support in the associations between psychological distress and somatic health problems and socio-economic factors among older adults living at home. The objectives of the present study were to investigate the associations of social support, somatic health problems and socio-economic factors with psychological distress. We also examined changes in the association of somatic health problems and socio-economic factors with psychological distress after adjusting for social support. Methods A random sample of 4,000 persons aged 65 years or more living at home in Oslo was drawn. Questionnaires were sent by post, and the total response was 2,387 (64%). Psychological distress was assessed using Hopkins Symptom Checklist (HSCL-10) and social support with the Oslo-3 Social Support Scale (OSS-3). A principal component analysis (PCA) included all items of social support and psychological distress. Partial correlations were used, while associations were studied by logistic regression. Results After adjusting for socio-demographics and somatic health problems, we reported a statistically significant association between psychological distress and social support: “Number of close friends”, OR 0.61; 95% CI 0.47-0.80; “Concern and interest”, OR 0.68; 95% CI 0.55-0.84. A strong association between lack of social support and psychological distress, irrespective of variables adjusted for, indicated a direct effect. The associations between psychological distress and physical impairments were somewhat reduced when adjusted for social support, particularly for hearing, whereas the associations between somatic diagnoses and psychological distress were more or less eliminated. Income was found to be an independent determinant for psychological distress. Conclusions Lack of social support and somatic health problems were associated with psychological distress in elders. Social support acted as a mediator, implying that the

  13. Gas exchange in the filamentous cyanobacterium Nostoc punctiforme strain ATCC 29133 and Its hydrogenase-deficient mutant strain NHM5.

    PubMed

    Lindberg, Pia; Lindblad, Peter; Cournac, Laurent

    2004-04-01

    Nostoc punctiforme ATCC 29133 is a nitrogen-fixing, heterocystous cyanobacterium of symbiotic origin. During nitrogen fixation, it produces molecular hydrogen (H(2)), which is recaptured by an uptake hydrogenase. Gas exchange in cultures of N. punctiforme ATCC 29133 and its hydrogenase-free mutant strain NHM5 was studied. Exchange of O(2), CO(2), N(2), and H(2) was followed simultaneously with a mass spectrometer in cultures grown under nitrogen-fixing conditions. Isotopic tracing was used to separate evolution and uptake of CO(2) and O(2). The amount of H(2) produced per molecule of N(2) fixed was found to vary with light conditions, high light giving a greater increase in H(2) production than N(2) fixation. The ratio under low light and high light was approximately 1.4 and 6.1 molecules of H(2) produced per molecule of N(2) fixed, respectively. Incubation under high light for a longer time, until the culture was depleted of CO(2), caused a decrease in the nitrogen fixation rate. At the same time, hydrogen production in the hydrogenase-deficient strain was increased from an initial rate of approximately 6 micro mol (mg of chlorophyll a)(-1) h(-1) to 9 micro mol (mg of chlorophyll a)(-1) h(-1) after about 50 min. A light-stimulated hydrogen-deuterium exchange activity stemming from the nitrogenase was observed in the two strains. The present findings are important for understanding this nitrogenase-based system, aiming at photobiological hydrogen production, as we have identified the conditions under which the energy flow through the nitrogenase can be directed towards hydrogen production rather than nitrogen fixation.

  14. Differential operation of dual protochlorophyllide reductases for chlorophyll biosynthesis in response to environmental oxygen levels in the cyanobacterium Leptolyngbya boryana.

    PubMed

    Yamazaki, Shoji; Nomata, Jiro; Fujita, Yuichi

    2006-11-01

    Most oxygenic phototrophs, including cyanobacteria, have two structurally unrelated protochlorophyllide (Pchlide) reductases in the penultimate step of chlorophyll biosynthesis. One is light-dependent Pchlide reductase (LPOR) and the other is dark-operative Pchlide reductase (DPOR), a nitrogenase-like enzyme assumed to be sensitive to oxygen. Very few studies have been conducted on how oxygen-sensitive DPOR operates in oxygenic phototrophic cells. Here, we report that anaerobic conditions are required for DPOR to compensate for the loss of LPOR in cyanobacterial cells. An LPOR-lacking mutant of the cyanobacterium Leptolyngbya boryana (formerly Plectonema boryanum) failed to grow in high light conditions and this phenotype was overcome by cultivating it under anaerobic conditions (2% CO(2)/N(2)). The critical oxygen level enabling the mutant to grow in high light was determined to be 3% (v/v). Oxygen-sensitive Pchlide reduction activity was successfully detected as DPOR activity in cell-free extracts of anaerobically grown mutants, whereas activity was undetectable in the wild type. The content of two DPOR subunits, ChlL and ChlN, was significantly increased in mutant cells compared with wild type. This suggests that the increase in subunits stimulates the DPOR activity that is protected efficiently from oxygen by anaerobic environments, resulting in complementation of the loss of LPOR. These results provide important concepts for understanding how dual Pchlide reductases operate differentially in oxygenic photosynthetic cells grown under natural environments where oxygen levels undergo dynamic changes. The evolutionary implications of the coexistence of two Pchlide reductases are discussed.

  15. The uptake hydrogenase in the unicellular diazotrophic cyanobacterium Cyanothece sp. strain PCC 7822 protects nitrogenase from oxygen toxicity.

    PubMed

    Zhang, Xiaohui; Sherman, Debra M; Sherman, Louis A

    2014-02-01

    Cyanothece sp. strain PCC 7822 is a unicellular, diazotrophic cyanobacterium that can produce large quantities of H2 when grown diazotrophically. This strain is also capable of genetic manipulations and can represent a good model for improving H2 production from cyanobacteria. To this end, a knockout mutation was made in the hupL gene (ΔhupL), and we determined how this would affect the amount of H2 produced. The ΔhupL mutant demonstrated virtually no nitrogenase activity or H2 production when grown under N2-fixing conditions. To ensure that this mutation only affected the hupL gene, a complementation strain was constructed readily with wild-type properties; this indicated that the original insertion was only in hupL. The mutant had no uptake hydrogenase activity but had increased bidirectional hydrogenase (Hox) activity. Western blotting and immunocytochemistry under the electron microscope indicated that the mutant had neither HupL nor NifHDK, although the nif genes were transcribed. Interestingly, biochemical analysis demonstrated that both HupL and NifH could be membrane associated. The results indicated that the nif genes were transcribed but that NifHDK was either not translated or was translated but rapidly degraded. We hypothesized that the Nif proteins were made but were unusually susceptible to O2 damage. Thus, we grew the mutant cells under anaerobic conditions and found that they grew well under N2-fixing conditions. We conclude that in unicellular diazotrophs, like Cyanothece sp. strain PCC 7822, the HupLS complex helps remove oxygen from the nitrogenase, and that this is a more important function than merely oxidizing the H2 produced by the nitrogenase.

  16. Biosynthesis of platform chemical 3-hydroxypropionic acid (3-HP) directly from CO2 in cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Wang, Yunpeng; Sun, Tao; Gao, Xingyan; Shi, Mengliang; Wu, Lina; Chen, Lei; Zhang, Weiwen

    2016-03-01

    3-hydroxypropionic acid (3-HP) is an important platform chemical with a wide range of applications. So far large-scale production of 3-HP has been mainly through petroleum-based chemical processes, whose sustainability and environmental issues have attracted widespread attention. With the ability to fix CO2 directly, cyanobacteria have been engineered as an autotrophic microbial cell factory to produce fuels and chemicals. In this study, we constructed the biosynthetic pathway of 3-HP in cyanobacterium Synechocystis sp. PCC 6803, and then optimized the system through the following approaches: i) increasing expression of malonyl-CoA reductase (MCR) gene using different promoters and cultivation conditions; ii) enhancing supply of the precursor malonyl-CoA by overexpressing acetyl-CoA carboxylase and biotinilase; iii) improving NADPH supply by overexpressing the NAD(P) transhydrogenase gene; iv) directing more carbon flux into 3-HP by inactivating the competing pathways of PHA and acetate biosynthesis. Together, the efforts led to a production of 837.18 mg L(-1) (348.8 mg/g dry cell weight) 3-HP directly from CO2 in Synechocystis after 6 days cultivation, demonstrating the feasibility photosynthetic production of 3-HP directly from sunlight and CO2 in cyanobacteria. In addition, the results showed that overexpression of the ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) gene from Anabaena sp. PCC 7120 and Synechococcus sp. PCC 7942 led to no increase of 3-HP production, suggesting CO2 fixation may not be a rate-limiting step for 3-HP biosynthesis in Synechocystis.

  17. The influence of iron limitation on the growth and activity of Crocosphaera watsonii, an unicellular diazotrophic cyanobacterium

    NASA Astrophysics Data System (ADS)

    Jacq, V.; Ridame, C.

    2012-04-01

    Diazotrophic cyanobacteria are able to use atmospheric dinitrogen (N2) dissolved in seawater as source of nitrogen for primary production. This metabolic function confers an ecological advantage for such organisms in N-limited environments, such as tropical oligotrophic regions. There, N2 fixation represents a significant source of new nitrogen in the euphotic zone which is available for the non diazotrophic phytoplankton community. Thus, diazotrophic cyanobacteria contribute significantly to new production and play a key role in the global cycling of carbon and nitrogen. The filamentous diazotrophic cyanobacterium Trichodesmium is the best known and most studied marine diazotroph. However, recent research has highlighted the biogeochemical importance of unicellular diazotrophic cyanobacteria (UCYN), such as Crocosphaera watsonii. The factors that control N2 fixation have been intensively studied. Due to the high iron content of the nitrogenase enzyme complex, N2 fixation and growth of diazotrophic cyanobacteria can be controlled by iron bioavailability. Many studies have been conducted on the impact of iron limitation on Trichodesmium, but less is known for UCYN. Here, for the first time, we address the issue of iron limitation on the N2 fixation and growth of UCYN, namely Crocosphaera watsonii. We have designed a study on cultures of Crocosphaera watsonii strain WH8501 grown under a range of dissolved iron, from 2 nM to 400 nM, with a constant EDTA concentration of 2 µM. Our experiment encompasses low iron concentrations (2 nM), representative of those measured in the field. Preliminary findings demonstrate a major control of iron availability on the biomass and growth of Crocosphaera watsonii. These results, complemented with data on photosynthetic and diazotrophic activities, significantly contribute to our understanding of the dynamics of N2 fixation by unicellular diazotrophic cyanobacteria and of the role of iron in controlling this process. Keywords: N2

  18. Salinity Tolerance of Picochlorum atomus and the Use of Salinity for Contamination Control by the Freshwater Cyanobacterium Pseudanabaena limnetica

    PubMed Central

    von Alvensleben, Nicolas; Stookey, Katherine; Magnusson, Marie; Heimann, Kirsten

    2013-01-01

    Microalgae are ideal candidates for waste-gas and –water remediation. However, salinity often varies between different sites. A cosmopolitan microalga with large salinity tolerance and consistent biochemical profiles would be ideal for standardised cultivation across various remediation sites. The aims of this study were to determine the effects of salinity on Picochlorum atomus growth, biomass productivity, nutrient uptake and biochemical profiles. To determine if target end-products could be manipulated, the effects of 4-day nutrient limitation were also determined. Culture salinity had no effect on growth, biomass productivity, phosphate, nitrate and total nitrogen uptake at 2, 8, 18, 28 and 36 ppt. 11 ppt, however, initiated a significantly higher total nitrogen uptake. While salinity had only minor effects on biochemical composition, nutrient depletion was a major driver for changes in biomass quality, leading to significant increases in total lipid, fatty acid and carbohydrate quantities. Fatty acid composition was also significantly affected by nutrient depletion, with an increased proportion of saturated and mono-unsaturated fatty acids. Having established that P. atomus is a euryhaline microalga, the effects of culture salinity on the development of the freshwater cyanobacterial contaminant Pseudanabaena limnetica were determined. Salinity at 28 and 36 ppt significantly inhibited establishment of P. limnetica in P. atomus cultures. In conclusion, P. atomus can be deployed for bioremediation at sites with highly variable salinities without effects on end-product potential. Nutrient status critically affected biochemical profiles – an important consideration for end-product development by microalgal industries. 28 and 36 ppt slow the establishment of the freshwater cyanobacterium P. limnetica, allowing for harvest of low contaminant containing biomass. PMID:23667639

  19. Salinity tolerance of Picochlorum atomus and the use of salinity for contamination control by the freshwater cyanobacterium Pseudanabaena limnetica.

    PubMed

    von Alvensleben, Nicolas; Stookey, Katherine; Magnusson, Marie; Heimann, Kirsten

    2013-01-01

    Microalgae are ideal candidates for waste-gas and -water remediation. However, salinity often varies between different sites. A cosmopolitan microalga with large salinity tolerance and consistent biochemical profiles would be ideal for standardised cultivation across various remediation sites. The aims of this study were to determine the effects of salinity on Picochlorum atomus growth, biomass productivity, nutrient uptake and biochemical profiles. To determine if target end-products could be manipulated, the effects of 4-day nutrient limitation were also determined. Culture salinity had no effect on growth, biomass productivity, phosphate, nitrate and total nitrogen uptake at 2, 8, 18, 28 and 36 ppt. 11 ppt, however, initiated a significantly higher total nitrogen uptake. While salinity had only minor effects on biochemical composition, nutrient depletion was a major driver for changes in biomass quality, leading to significant increases in total lipid, fatty acid and carbohydrate quantities. Fatty acid composition was also significantly affected by nutrient depletion, with an increased proportion of saturated and mono-unsaturated fatty acids. Having established that P. atomus is a euryhaline microalga, the effects of culture salinity on the development of the freshwater cyanobacterial contaminant Pseudanabaena limnetica were determined. Salinity at 28 and 36 ppt significantly inhibited establishment of P. limnetica in P. atomus cultures. In conclusion, P. atomus can be deployed for bioremediation at sites with highly variable salinities without effects on end-product potential. Nutrient status critically affected biochemical profiles--an important consideration for end-product development by microalgal industries. 28 and 36 ppt slow the establishment of the freshwater cyanobacterium P. limnetica, allowing for harvest of low contaminant containing biomass.

  20. Proteomic approaches to identify substrates of the three Deg/HtrA proteases of the cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Tam, Lam X; Aigner, Harald; Timmerman, Evy; Gevaert, Kris; Funk, Christiane

    2015-06-15

    The family of Deg/HtrA proteases plays an important role in quality control of cellular proteins in a wide range of organisms. In the genome of the cyanobacterium Synechocystis sp. PCC 6803, a model organism for photosynthetic research and renewable energy products, three Deg proteases are encoded, termed HhoA, HhoB and HtrA. In the present study, we compared wild-type (WT) Synechocystis cells with the single insertion mutants ΔhhoA, ΔhhoB and ΔhtrA. Protein expression of the remaining Deg/HtrA proteases was strongly affected in the single insertion mutants. Detailed proteomic studies using DIGE (difference gel electrophoresis) and N-terminal COFRADIC (N-terminal combined fractional diagonal chromatography) revealed that inactivation of a single Deg protease has similar impact on the proteomes of the three mutants; differences to WT were observed in enzymes involved in the major metabolic pathways. Changes in the amount of phosphate permease system Pst-1 were observed only in the insertion mutant ΔhhoB. N-terminal COFRADIC analyses on cell lysates of ΔhhoB confirmed changed amounts of many cell envelope proteins, including the phosphate permease systems, compared with WT. In vitro COFRADIC studies were performed to identify the specificity profiles of the recombinant proteases rHhoA, rHhoB or rHtrA added to the Synechocystis WT proteome. The combined in vivo and in vitro N-terminal COFRADIC datasets propose RbcS as a natural substrate for HhoA, PsbO for HhoB and HtrA and Pbp8 for HtrA. We therefore suggest that each Synechocystis Deg protease protects the cell through different, but connected mechanisms. © The Authors Journal compilation © 2015 Biochemical Society.

  1. The Uptake Hydrogenase in the Unicellular Diazotrophic Cyanobacterium Cyanothece sp. Strain PCC 7822 Protects Nitrogenase from Oxygen Toxicity

    PubMed Central

    Zhang, Xiaohui; Sherman, Debra M.

    2014-01-01

    Cyanothece sp. strain PCC 7822 is a unicellular, diazotrophic cyanobacterium that can produce large quantities of H2 when grown diazotrophically. This strain is also capable of genetic manipulations and can represent a good model for improving H2 production from cyanobacteria. To this end, a knockout mutation was made in the hupL gene (ΔhupL), and we determined how this would affect the amount of H2 produced. The ΔhupL mutant demonstrated virtually no nitrogenase activity or H2 production when grown under N2-fixing conditions. To ensure that this mutation only affected the hupL gene, a complementation strain was constructed readily with wild-type properties; this indicated that the original insertion was only in hupL. The mutant had no uptake hydrogenase activity but had increased bidirectional hydrogenase (Hox) activity. Western blotting and immunocytochemistry under the electron microscope indicated that the mutant had neither HupL nor NifHDK, although the nif genes were transcribed. Interestingly, biochemical analysis demonstrated that both HupL and NifH could be membrane associated. The results indicated that the nif genes were transcribed but that NifHDK was either not translated or was translated but rapidly degraded. We hypothesized that the Nif proteins were made but were unusually susceptible to O2 damage. Thus, we grew the mutant cells under anaerobic conditions and found that they grew well under N2-fixing conditions. We conclude that in unicellular diazotrophs, like Cyanothece sp. strain PCC 7822, the HupLS complex helps remove oxygen from the nitrogenase, and that this is a more important function than merely oxidizing the H2 produced by the nitrogenase. PMID:24317398

  2. Teaching Economic Reasoning to Children.

    ERIC Educational Resources Information Center

    Schug, Mark C.

    1996-01-01

    Discusses differences between young peoples' perspectives of the social world and those offered by social science. Summarizes the economic thinking of young people and argues that economics presents students with an important perspective for social analysis. Provides three "economic mysteries" that introduce economic principles into the classroom.…

  3. Behavioral economics.

    PubMed

    Camerer, Colin F

    2014-09-22

    Behavioral economics uses evidence from psychology and other social sciences to create a precise and fruitful alternative to traditional economic theories, which are based on optimization. Behavioral economics may interest some biologists, as it shifts the basis for theories of economic choice away from logical calculation and maximization and toward biologically plausible mechanisms.

  4. Transatlantic abundance of the N2-fixing colonial cyanobacterium Trichodesmium.

    PubMed

    Davis, Cabell S; McGillicuddy, Dennis J

    2006-06-09

    Colonial diazotrophic cyanobacteria of the genus Trichodesmium are thought to play a significant role in the input of new nitrogen to upper layers of the tropical and subtropical oceanic ecosystems that cover nearly half of Earth's surface. Here we describe results of a transatlantic survey in which a noninvasive underwater digital microscope (the video plankton recorder), was towed across the North Atlantic at 6 meters per second while undulating between the surface and 130 meters. Colony abundance had a basin-scale trend, a clear association with anticyclonic eddies, and was not affected by hurricane-forced mixing. Subsurface abundance was higher than previously reported, which has important implications for the global ocean nitrogen cycle.

  5. Techno-economic analysis of a conceptual biofuel production process from bioethylene produced by photosynthetic recombinant cyanobacteria

    DOE PAGES

    Markham, Jennifer N.; Tao, Ling; Davis, Ryan; ...

    2016-08-25

    Ethylene is a petrochemical produced in large volumes worldwide. It serves as a building block for a wide variety of plastics, textiles, and chemicals, and can be converted into liquid transportation fuels. There is great interest in the development of technologies that produce ethylene from renewable resources, such as biologically derived CO2 and biomass. One of the metabolic pathways used by microbes to produce ethylene is via an ethylene-forming enzyme (EFE). By expressing a bacterial EFE gene in a cyanobacterium, ethylene has been produced through photosynthetic carbon fixation. Here, we present a conceptual design and techno-economic analysis of a processmore » of biofuel production based on the upgradation of ethylene generated by the recombinant cyanobacterium. This analysis focuses on potential near-term to long-term cost projections for the integrated process of renewable fuels derived from ethylene. The cost projections are important in showing the potential of this technology and determining research thrusts needed to reach target goals. The base case for this analysis is a midterm projection using tubular photobioreactors for cyanobacterial growth and ethylene production, cryogenic distillation for ethylene separation and purification, a two-step Ziegler oligomerization process with subsequent hydrotreatment and upgradation for fuel production, and a wastewater treatment process that utilizes anaerobic digestion of cyanobacterial biomass. The minimum fuel selling price (MFSP) for the midterm projection is 15.07 per gallon gasoline equivalent (GGE). Near-term and long-term projections are 28.66 per GGE and 5.36 per GGE, respectively. Single- and multi-point sensitivity analyses are conducted to determine the relative effect that chosen variables could have on the overall costs. This analysis identifies several key variables for improving the overall process economics and outlines strategies to guide future research directions. Finally, the

  6. Techno-economic analysis of a conceptual biofuel production process from bioethylene produced by photosynthetic recombinant cyanobacteria

    SciTech Connect

    Markham, Jennifer N.; Tao, Ling; Davis, Ryan; Voulis, Nina; Angenent, Largus T.; Ungerer, Justin; Yu, Jianping

    2016-08-25

    Ethylene is a petrochemical produced in large volumes worldwide. It serves as a building block for a wide variety of plastics, textiles, and chemicals, and can be converted into liquid transportation fuels. There is great interest in the development of technologies that produce ethylene from renewable resources, such as biologically derived CO2 and biomass. One of the metabolic pathways used by microbes to produce ethylene is via an ethylene-forming enzyme (EFE). By expressing a bacterial EFE gene in a cyanobacterium, ethylene has been produced through photosynthetic carbon fixation. Here, we present a conceptual design and techno-economic analysis of a process of biofuel production based on the upgradation of ethylene generated by the recombinant cyanobacterium. This analysis focuses on potential near-term to long-term cost projections for the integrated process of renewable fuels derived from ethylene. The cost projections are important in showing the potential of this technology and determining research thrusts needed to reach target goals. The base case for this analysis is a midterm projection using tubular photobioreactors for cyanobacterial growth and ethylene production, cryogenic distillation for ethylene separation and purification, a two-step Ziegler oligomerization process with subsequent hydrotreatment and upgradation for fuel production, and a wastewater treatment process that utilizes anaerobic digestion of cyanobacterial biomass. The minimum fuel selling price (MFSP) for the midterm projection is 15.07 per gallon gasoline equivalent (GGE). Near-term and long-term projections are 28.66 per GGE and 5.36 per GGE, respectively. Single- and multi-point sensitivity analyses are conducted to determine the relative effect that chosen variables could have on the overall costs. This analysis identifies several key variables for improving the overall process economics and outlines strategies to guide future research directions. Finally, the

  7. Techno-economic analysis of a conceptual biofuel production process from bioethylene produced by photosynthetic recombinant cyanobacteria

    SciTech Connect

    Markham, Jennifer N.; Tao, Ling; Davis, Ryan; Voulis, Nina; Angenent, Largus T.; Ungerer, Justin; Yu, Jianping

    2016-08-25

    Ethylene is a petrochemical produced in large volumes worldwide. It serves as a building block for a wide variety of plastics, textiles, and chemicals, and can be converted into liquid transportation fuels. There is great interest in the development of technologies that produce ethylene from renewable resources, such as biologically derived CO2 and biomass. One of the metabolic pathways used by microbes to produce ethylene is via an ethylene-forming enzyme (EFE). By expressing a bacterial EFE gene in a cyanobacterium, ethylene has been produced through photosynthetic carbon fixation. Here, we present a conceptual design and techno-economic analysis of a process of biofuel production based on the upgradation of ethylene generated by the recombinant cyanobacterium. This analysis focuses on potential near-term to long-term cost projections for the integrated process of renewable fuels derived from ethylene. The cost projections are important in showing the potential of this technology and determining research thrusts needed to reach target goals. The base case for this analysis is a midterm projection using tubular photobioreactors for cyanobacterial growth and ethylene production, cryogenic distillation for ethylene separation and purification, a two-step Ziegler oligomerization process with subsequent hydrotreatment and upgradation for fuel production, and a wastewater treatment process that utilizes anaerobic digestion of cyanobacterial biomass. The minimum fuel selling price (MFSP) for the midterm projection is 15.07 per gallon gasoline equivalent (GGE). Near-term and long-term projections are 28.66 per GGE and 5.36 per GGE, respectively. Single- and multi-point sensitivity analyses are conducted to determine the relative effect that chosen variables could have on the overall costs. This analysis identifies several key variables for improving the overall process economics and outlines strategies to guide future research directions. Finally, the

  8. Strategy to obtain axenic cultures from field-collected samples of the cyanobacterium Phormidium animalis.

    PubMed

    Vázquez-Martínez, Guadalupe; Rodriguez, Mario H; Hernández-Hernández, Fidel; Ibarra, Jorge E

    2004-04-01

    An efficient strategy, based on a combination of procedures, was developed to obtain axenic cultures from field-collected samples of the cyanobacterium Phormidium animalis. Samples were initially cultured in solid ASN-10 medium, and a crude separation of major contaminants from P. animalis filaments was achieved by washing in a series of centrifugations and resuspensions in liquid medium. Then, manageable filament fragments were obtained by probe sonication. Fragmentation was followed by forceful washing, using vacuum-driven filtration through an 8-microm pore size membrane and an excess of water. Washed fragments were cultured and treated with a sequential exposure to four different antibiotics. Finally, axenic cultures were obtained from serial dilutions of treated fragments. Monitoring under microscope examination and by inoculation in Luria-Bertani (LB) agar plates indicated either axenicity or the degree of contamination throughout the strategy.

  9. Unique modification of adenine in genomic DNA of the marine cyanobacterium Trichodesmium sp. strain NIBB 1067.

    PubMed Central

    Zehr, J P; Ohki, K; Fujita, Y; Landry, D

    1991-01-01

    The genomic DNA of the marine nonheterocystous nitrogen-fixing cyanobacterium Trichodesmium sp. strain NIBB 1067 was found to be highly resistant to DNA restriction endonucleases. The DNA was digested extensively by the restriction enzyme DpnI, which requires adenine methylation for activity. The DNA composition, determined by high-performance liquid chromatography (HPLC), was found to be 69% AT. Surprisingly, it was found that a modified adenine which was not methylated at the usual N6 position was present and made up 4.7 mol% of the nucleosides in Trichodesmium DNA (15 mol% of deoxyadenosine). In order for adenine residues to be modified at this many positions, there must be many modifying enzymes or at least one of the modifying enzymes must have a degenerate recognition site. The reason(s) for this extensive methylation has not yet been determined but may have implications for the ecological success of this microorganism in nature. Images FIG. 1 FIG. 2 PMID:1657876

  10. Flocculation properties of several microalgae and a cyanobacterium species during ferric chloride, chitosan and alkaline flocculation.

    PubMed

    Lama, Sanjaya; Muylaert, Koenraad; Karki, Tika Bahadur; Foubert, Imogen; Henderson, Rita K; Vandamme, Dries

    2016-11-01

    Flocculation holds great potential as a low-cost harvesting method for microalgae biomass production. Three flocculation methods (ferric chloride, chitosan, and alkaline flocculation) were compared in this study for the harvesting of 9 different freshwater and marine microalgae and one cyanobacterium species. Ferric chloride resulted in a separation efficiency greater than 90% with a concentration factor (CF) higher than 10 for all species. Chitosan flocculation worked generally very well for freshwater microalgae, but not for marine species. Alkaline flocculation was most efficient for harvesting of Nannochloropsis, Chlamydomonas and Chlorella sp. The concentration factor was highly variable between microalgae species. Generally, minimum flocculant dosages were highly variable across species, which shows that flocculation may be a good harvesting method for some species but not for others. This study shows that microalgae and cyanobacteria species should not be selected solely based on their productivity but also on their potential for low-cost separation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Back from the dead; the curious tale of the predatory cyanobacterium Vampirovibrio chlorellavorus

    PubMed Central

    Soo, Rochelle M.; Woodcroft, Ben J.; Parks, Donovan H.; Tyson, Gene W.

    2015-01-01

    An uncultured non-photosynthetic basal lineage of the Cyanobacteria, the Melainabacteria, was recently characterised by metagenomic analyses of aphotic environmental samples. However, a predatory bacterium, Vampirovibrio chlorellavorus, originally described in 1972 appears to be the first cultured representative of the Melainabacteria based on a 16S rRNA sequence recovered from a lyophilised co-culture of the organism. Here, we sequenced the genome of V. chlorellavorus directly from 36 year-old lyophilised material that could not be resuscitated confirming its identity as a member of the Melainabacteria. We identified attributes in the genome that likely allow V. chlorellavorus to function as an obligate predator of the microalga Chlorella vulgaris, and predict that it is the first described predator to use an Agrobacterium tumefaciens-like conjugative type IV secretion system to invade its host. V. chlorellavorus is the first cyanobacterium recognised to have a predatory lifestyle and further supports the assertion that Melainabacteria are non-photosynthetic. PMID:26038723

  12. Sesquiterpenes of the geosmin-producing cyanobacterium Calothrix PCC 7507 and their toxicity to invertebrates.

    PubMed

    Höckelmann, Claudia; Becher, Paul G; von Reuss, Stephan H; Jüttner, Friedrich

    2009-01-01

    The occurrence of sesquiterpenes was investigated with the geosmin-producing cyanobacterium Calothrix PCC 7507. The essential oil obtained by vacuum destillation was studied in more detail by GC-MS methods and superposition with authentic compounds. Geosmin was the dominating compound while the other sesquiterpenes were minor components. Sesquiterpenes that have not been described before in cyanobacteria were isodihydroagarofuran, eremophilone and 6,11-epoxyisodaucane. Closed-loop stripping analysis revealed that most of the sesquiterpenes were found in the biomass of Calothrix, while eremophilone was mainly observed in the medium of the axenic culture. Eremophilone showed acute toxicity (LC50) against Chironomus riparius (insecta) at 29 microM and against Thamnocephalus platyurus (crustacea) at 22 microM. The compound was not toxic for Plectus cirratus (nematoda). 6,11-Epoxyisodaucane and isodihydroagarofuran exhibited no toxicity to invertebrates when applied in concentrations up to 100 microM.

  13. Ribulose-1,5-bisphosphate carboxylase/oxygenase from thermophilic cyanobacterium Thermosynechococcus elongatus.

    PubMed

    Gubernator, Beata; Bartoszewski, Rafal; Kroliczewski, Jaroslaw; Wildner, Guenter; Szczepaniak, Andrzej

    2008-01-01

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) can be divided into two branches: the "red-like type" of marine algae and the "green-like type" of cyanobacteria, green algae, and higher plants. We found that the "green-like type" rubisco from the thermophilic cyanobacterium Thermosynechococcus elongatus has an almost 2-fold higher specificity factor compared with rubiscos of mesophilic cyanobacteria, reaching the values of higher plants, and simultaneously revealing an improvement in enzyme thermostability. The difference in the activation energies at the transition stages between the oxygenase and carboxylase reactions for Thermosynechococcus elongatus rubisco is very close to that of Galdieria partita and significantly higher than that of spinach. This is the first characterization of a "green-like type" rubisco from thermophilic organism.

  14. Sacrolide A, a new antimicrobial and cytotoxic oxylipin macrolide from the edible cyanobacterium Aphanothece sacrum

    PubMed Central

    Oku, Naoya; Matsumoto, Miyako; Yonejima, Kohsuke; Tansei, Keijiroh

    2014-01-01

    Summary Macroscopic gelatinous colonies of freshwater cyanobacterium Aphanothece sacrum, a luxury ingredient for Japanese cuisine, were found to contain a new oxylipin-derived macrolide, sacrolide A (1), as an antimicrobial component. The configuration of two chiral centers in 1 was determined by a combination of chiral anisotropy analysis and conformational analysis of different ring-opened derivatives. Compound 1 inhibited the growth of some species of Gram-positive bacteria, yeast Saccharomyces cerevisiae and fungus Penicillium chrysogenum, and was also cytotoxic to 3Y1 rat fibroblasts. Concern about potential food intoxication caused by accidental massive ingestion of A. sacrum was dispelled by the absence of 1 in commercial products. A manual procedure for degrading 1 in raw colonies was also developed, enabling a convenient on-site detoxification at restaurants or for personal consumption. PMID:25161741

  15. Sacrolide A, a new antimicrobial and cytotoxic oxylipin macrolide from the edible cyanobacterium Aphanothece sacrum.

    PubMed

    Oku, Naoya; Matsumoto, Miyako; Yonejima, Kohsuke; Tansei, Keijiroh; Igarashi, Yasuhiro

    2014-01-01

    Macroscopic gelatinous colonies of freshwater cyanobacterium Aphanothece sacrum, a luxury ingredient for Japanese cuisine, were found to contain a new oxylipin-derived macrolide, sacrolide A (1), as an antimicrobial component. The configuration of two chiral centers in 1 was determined by a combination of chiral anisotropy analysis and conformational analysis of different ring-opened derivatives. Compound 1 inhibited the growth of some species of Gram-positive bacteria, yeast Saccharomyces cerevisiae and fungus Penicillium chrysogenum, and was also cytotoxic to 3Y1 rat fibroblasts. Concern about potential food intoxication caused by accidental massive ingestion of A. sacrum was dispelled by the absence of 1 in commercial products. A manual procedure for degrading 1 in raw colonies was also developed, enabling a convenient on-site detoxification at restaurants or for personal consumption.

  16. BMAA inhibits nitrogen fixation in the cyanobacterium Nostoc sp. PCC 7120.

    PubMed

    Berntzon, Lotta; Erasmie, Sven; Celepli, Narin; Eriksson, Johan; Rasmussen, Ulla; Bergman, Birgitta

    2013-08-21

    Cyanobacteria produce a range of secondary metabolites, one being the neurotoxic non-protein amino acid β-N-methylamino-L-alanine (BMAA), proposed to be a causative agent of human neurodegeneration. As for most cyanotoxins, the function of BMAA in cyanobacteria is unknown. Here, we examined the effects of BMAA on the physiology of the filamentous nitrogen-fixing cyanobacterium Nostoc sp. PCC 7120. Our data show that exogenously applied BMAA rapidly inhibits nitrogenase activity (acetylene reduction assay), even at micromolar concentrations, and that the inhibition was considerably more severe than that induced by combined nitrogen sources and most other amino acids. BMAA also caused growth arrest and massive cellular glycogen accumulation, as observed by electron microscopy. With nitrogen fixation being a process highly sensitive to oxygen species we propose that the BMAA effects found here may be related to the production of reactive oxygen species, as reported for other organisms.

  17. Molecular cloning of a recA-like gene from the cyanobacterium Anabaena variabilis.

    PubMed Central

    Owttrim, G W; Coleman, J R

    1987-01-01

    A recA-like gene isolated from the cyanobacterium Anabaena variabilis was cloned and partially characterized. When introduced into Escherichia coli recA mutants, the 7.5-kilobase-pair plasmid-borne DNA insert restored resistance to methyl methanesulfonate and UV irradiation, as well as recombination proficiency when measured by Hfr-mediated conjugation. The cyanobacterial recA gene restored spontaneous but not mitomycin C-induced prophage production. Restriction analysis and subcloning yielded a 1.5-kilobase-pair Sau3A fragment which also restored methylmethane sulfonate resistance and coded for a 38- to 40-kilodalton polypeptide when expressed in an in vitro transcription-translation system. Images PMID:3032896

  18. Tiglicamides A–C, cyclodepsipeptides from the marine cyanobacterium Lyngbya confervoides

    PubMed Central

    Matthew, Susan; Paul, Valerie J.; Luesch, Hendrik

    2009-01-01

    The Floridian marine cyanobacterium Lyngbya confervoides afforded three new cyclodepsipeptides, termed tiglicamides A–C (1–3), along with their previously reported analogues largamides A–C (4–6), all of which possess an unusual tiglic acid moiety. Their structures were deduced by one- and two-dimensional NMR combined with mass spectrometry and the absolute configurations established by chiral HPLC and Marfey’s analysis of the degradation products. Compounds 1–3 moderately inhibited porcine pancreatic elastase in vitro with IC50 values from 2.14 to 7.28 µM. Compounds 1–6 differ from each other by one amino acid residue within the cyclic core structure, suggesting an unusually relaxed substrate specificity of the nonribosomal peptide synthetase that is the putative biosynthetic enzyme responsible for the corresponding amino acid incorporation. PMID:19815244

  19. Composition and occurrence of lipid droplets in the cyanobacterium Nostoc punctiforme

    PubMed Central

    Peramuna, Anantha; Summers, Michael L.

    2014-01-01

    Inclusions of neutral lipids termed lipid droplets (LDs) located throughout the cell were identified in the cyanobacterium Nostoc punctiforme by staining with lipophyllic fluorescent dyes. LDs increased in number upon entry into stationary phase and addition of exogenous fructose indicating a role for carbon storage, whereas high-light stress did not increase LD numbers. LD accumulation increased when nitrate was used as the nitrogen source during exponential growth as compared to added ammonia or nitrogen–fixing conditions. Analysis of isolated LDs revealed enrichment of triacylglycerol (TAG), - tochopherol, and C17 alkanes. LD TAG from exponential phase growth contained mainly saturated C16 and C18 fatty acids whereas stationary phase LD TAG had additional unsaturated fatty acids characteristic of whole cells. This is the first characterization of cyanobacterial LD composition and conditions leading to their production. Based upon their abnormally large size and atypical location these structures represent a novel sub-organelle in cyanobacteria. PMID:25135835

  20. Space-environmental tolerances in a cyanobacterium, Nostoc sp. HK-01

    NASA Astrophysics Data System (ADS)

    Tomita-Yokotani, Kaori; Yokobori, Shin-ichi; Kimura, Shunta; Sato, Seigo; Katoh, Hiroshi; Ajioka, Reiko; Yamagishi, Akihiko; Inoue, Kotomi

    2016-07-01

    We have been investigating the tolerances to space-environments of a cyanobacterium, Nostoc sp. HK-01 (hereafter referred to as HK-01). Dry colonies of HK-01 had high tolerance to dry conditions, but more detailed information about tolerance to high-temperature, UV, gamma-ray and heavy particle beams were not deeply investigated. The obtained dry colonies of HK-01 after exposure to each of the conditions described above were investigated. In all of the tested colonies of HK-01 after exposure, all or some of the cells in the colonies were alive. One of the purposes of space agriculture is growing plants on Mars. In the early stages, of our research, cyanobacteria are introduced on Mars to promote the oxidation of the atmosphere and the formation of soil from Mars's regolith. HK-01 will contribute to each of these factors in the future.

  1. BMAA Inhibits Nitrogen Fixation in the Cyanobacterium Nostoc sp. PCC 7120

    PubMed Central

    Berntzon, Lotta; Erasmie, Sven; Celepli, Narin; Eriksson, Johan; Rasmussen, Ulla; Bergman, Birgitta

    2013-01-01

    Cyanobacteria produce a range of secondary metabolites, one being the neurotoxic non-protein amino acid β-N-methylamino-L-alanine (BMAA), proposed to be a causative agent of human neurodegeneration. As for most cyanotoxins, the function of BMAA in cyanobacteria is unknown. Here, we examined the effects of BMAA on the physiology of the filamentous nitrogen-fixing cyanobacterium Nostoc sp. PCC 7120. Our data show that exogenously applied BMAA rapidly inhibits nitrogenase activity (acetylene reduction assay), even at micromolar concentrations, and that the inhibition was considerably more severe than that induced by combined nitrogen sources and most other amino acids. BMAA also caused growth arrest and massive cellular glycogen accumulation, as observed by electron microscopy. With nitrogen fixation being a process highly sensitive to oxygen species we propose that the BMAA effects found here may be related to the production of reactive oxygen species, as reported for other organisms. PMID:23966039

  2. Isolation, purification and characterization of the ATPase complex from the thermophilic cyanobacterium Synechococcus 6716.

    PubMed

    Lubberding, H J; Zimmer, G; van Walraven, H S; Schrickx, J; Kraayenhof, R

    1983-12-01

    The ATPase complex is isolated and purified from membrane vesicles of the thermophilic cyanobacterium Synechococcus 6716 by octyl glucoside and cholic acid by a modification of the procedure for its extraction from spinach chloroplasts. The complex is purified by differential centrifugation and ammonium sulfate precipitation and by gel filtration on Sepharose 6B. The purified fraction, without any phycocyanin contamination, shows ATP hydrolysis activity and Pi/ATP exchange activity of 1564 and 350 nmol X min-1 X mg protein-1, respectively. N,N'-Dicyclohexylcarbodiimide inhibits the ATP hydrolysis activity of this purified fraction. On polyacrylamide gels most typical F1 ATPase polypeptides are identified, but the low-molecular weight polypeptides visible cannot be ascribed to the F0 part of the complex with certainty; non-identified bands around 30 kDa are also present.

  3. Synthetic Biology Toolbox for Controlling Gene Expression in the Cyanobacterium Synechococcus sp. strain PCC 7002

    PubMed Central

    2015-01-01

    The application of synthetic biology requires characterized tools to precisely control gene expression. This toolbox of genetic parts previously did not exist for the industrially promising cyanobacterium, Synechococcus sp. strain PCC 7002. To address this gap, two orthogonal constitutive promoter libraries, one based on a cyanobacterial promoter and the other ported from Escherichia coli, were built and tested in PCC 7002. The libraries demonstrated 3 and 2.5 log dynamic ranges, respectively, but correlated poorly with E. coli expression levels. These promoter libraries were then combined to create and optimize a series of IPTG inducible cassettes. The resultant induction system had a 48-fold dynamic range and was shown to out-perform Ptrc constructs. Finally, a RBS library was designed and tested in PCC 7002. The presented synthetic biology toolbox will enable accelerated engineering of PCC 7002. PMID:25216157

  4. Metabolism of phenanthrene by the marine cyanobacterium Agmenellum quadruplicatum PR-6

    SciTech Connect

    Narro, M.L.; Baalen, C. van ); Cerniglia, C.E. ); Gibson, D.T. )

    1992-04-01

    Under photoautotrophic growth conditions, the marine cyanobacterium Agmenellum quadruplicatum PR-6 metabolized phenanthrene to form trans-9,10-dihydrophenanthrene (phenanthrene trans-9,10-dihydrodiol) and 1-methoxyphenanthrene as the major ethyl acetate-extractable metabolites. Small amounts of phenanthrols were also formed. The metabolites were purified by high-pressure liquid chromatography and identified from their UV, infrared, mass and proton magnetic resonance spectral properties. A. quadruplicatum PR-6 formed phenanthrene trans-9,10-dihydrodiol with a 22% enantiomeric excess of the ({minus})-9S,10S-enantiomer. Incorporation experiments with {sup 18}O{sub 2} showed that one atom of oxygen from O{sub 2} was incorporated into the dihydrodiol. Toxicity studies, using an algal lawn bioassay, indicated that 9-phenanthrol and 9,10-phenanthrenequinone inhibit the growth of A. quadruplicatum PR-6.

  5. The carmaphycins: new proteasome inhibitors exhibiting an α,β-epoxyketone warhead from a marine cyanobacterium.

    PubMed

    Pereira, Alban R; Kale, Andrew J; Fenley, Andrew T; Byrum, Tara; Debonsi, Hosana M; Gilson, Michael K; Valeriote, Frederick A; Moore, Bradley S; Gerwick, William H

    2012-04-16

    Two new peptidic proteasome inhibitors were isolated as trace components from a Curaçao collection of the marine cyanobacterium Symploca sp. Carmaphycin A (1) and carmaphycin B (2) feature a leucine-derived α,β-epoxyketone warhead directly connected to either methionine sulfoxide or methionine sulfone. Their structures were elucidated on the basis of extensive NMR and MS analyses and confirmed by total synthesis, which in turn provided more material for further biological evaluations. Pure carmaphycins A and B were found to inhibit the β5 subunit (chymotrypsin-like activity) of the S. cerevisiae 20S proteasome in the low nanomolar range. Additionally, they exhibited strong cytotoxicity to lung and colon cancer cell lines, as well as exquisite antiproliferative effects in the NCI60 cell-line panel. These assay results as well as initial structural biology studies suggest a distinctive binding mode for these new inhibitors.

  6. Laucysteinamide A, a Hybrid PKS/NRPS Metabolite from a Saipan Cyanobacterium, cf. Caldora penicillata.

    PubMed

    Zhang, Chen; Naman, C Benjamin; Engene, Niclas; Gerwick, William H

    2017-04-14

    A bioactivity guided study of a cf. Caldora penicillata species, collected during a 2013 expedition to the Pacific island of Saipan, Northern Mariana Islands (a commonwealth of the USA), led to the isolation of a new thiazoline-containing alkaloid, laucysteinamide A (1). Laucysteinamide A is a new monomeric analogue of the marine cyanobacterial metabolite, somocystinamide A (2), a disulfide-bonded dimeric compound that was isolated previously from a Fijian marine cyanobacterium. The structure and absolute configuration of laucysteinamide A (1) was determined by a detailed analysis of its NMR, MS, and CD spectra. In addition, the highly bioactive lipid, curacin D (3), was also found to be present in this cyanobacterial extract. The latter compound was responsible for the potent cytotoxicity of this extract to H-460 human non-small cell lung cancer cells in vitro.

  7. Regulatory effect of hydrogen on nitrogenase activity of the blue-green alga (cyanobacterium) Nostoc muscorum.

    PubMed

    Scherer, S; Kerfin, W; Böger, P

    1980-03-01

    Preincubation of the blue-green alga (cyanobacterium) Nostoc muscorum under an atmosphere of argon plus acetylene in the light led to a greater than fourfold increase of light-induced hydrogen evolution and to a 50% increase of acetylene reduction, as compared to cells that had not been preconditioned. The basic and the increased hydrogen evolution were both due to nitrogenase activity. Furthermore, after preincubation the hydrogen uptake, usually observed with unconditional cells, was abolished. Nostoc preincubated under acetylene evolved hydrogen in the light even in the presence of nitrogen for at least 2 h, with a 15-fold increase as compared to the unconditioned cells. These acetylene effects could be completely abolished by the presence of hydrogen during acetylene preincubation. These findings indicate that the hydrogen concentration in N. muscorum cells plays a role in regulation of nitrogenase activity.

  8. Period doubling observed in the circadian photosynthetic rhythm of the prokaryotic cyanobacterium Cyanothece RF-1

    NASA Astrophysics Data System (ADS)

    Yen, Tsu-Chiang; Cheng, Da-Long

    2005-03-01

    The circadian rhythm is an endogenous biological clock that governs biochemical phenomena or behavior in organisms. The Cyanothece RF-1 is the first prokaryote shown to exhibit circadian nitrogen-fixing rhythm. The observation of the circadian photosynthetic rhythm of this strain was recently reported by the authors. In this work, the dissolved-oxygen variation in the culture of Cyanothece RF-1 was recorded, which would reveal the photosynthetic activity of the strain. For a culture of about 1x10^8 cells/ml in concentration, a period-doubling pattern was clearly displayed in the circadian photosynthetic rhythm signals. The mechanism corresponding to this nonlinear effect will be discussed. These results represent the first observation of the period doubling in the circadian rhythm of a prokaryotic cyanobacterium.

  9. Salinity induced synthesis of UV-screening compound scytonemin in the cyanobacterium Lyngbya aestuarii.

    PubMed

    Rath, Jnanendra; Mandal, Sikha; Adhikary, Siba Prasad

    2012-10-03

    Lyngbya aestuarii is the dominant cyanobacterium in Chilika lagoon occurring in all the seasons irrespective of variation in the salinity regime ranging from 3 to 28 ppt. The organism possess the UV screening scytonemin pigment, which was maximum when grown at 56 ppt salinity. Three different forms of scytonemin were detected in L. aestuarii with retention time (RT) 1.76, 2.42 and 2.94 min, however, occurrence of these forms was influenced by the salinity. Scytonemin with RT 2.42 was sensitive to higher salinity and its maximum concentration was obtained at 28 ppt salinity correlated with the highest salinity level of Chilika. Formation of multilayer colored sheath around the trichome was prominently observed at the salinity of the culture from 28 to 56 ppt. But at salinity below 7 ppt and also at more than 56 ppt salinity degradation of sheath with corresponding decrease in scytonemin was observed.

  10. Composition and occurrence of lipid droplets in the cyanobacterium Nostoc punctiforme.

    PubMed

    Peramuna, Anantha; Summers, Michael L

    2014-12-01

    Inclusions of neutral lipids termed lipid droplets (LDs) located throughout the cell were identified in the cyanobacterium Nostoc punctiforme by staining with lipophylic fluorescent dyes. LDs increased in number upon entry into stationary phase and addition of exogenous fructose indicating a role for carbon storage, whereas high-light stress did not increase LD numbers. LD accumulation increased when nitrate was used as the nitrogen source during exponential growth as compared to added ammonia or nitrogen-fixing conditions. Analysis of isolated LDs revealed enrichment of triacylglycerol (TAG), α-tocopherol, and C17 alkanes. LD TAG from exponential phase growth contained mainly saturated C16 and C18 fatty acids, whereas stationary phase LD TAG had additional unsaturated fatty acids characteristic of whole cells. This is the first characterization of cyanobacterial LD composition and conditions leading to their production. Based upon their abnormally large size and atypical location, these structures represent a novel sub-organelle in cyanobacteria.

  11. Molecular cloning of a recA-like gene from the cyanobacterium Anabaena variabilis

    SciTech Connect

    Owttrim, G.W.; Coleman, J.R.

    1987-05-01

    A recA-like gene isolated from the cyanobacterium Anabaena variabilis was cloned and partially characterized. When introduced into Escherichia coli recA mutants, the 7.5-kilobase-pair plasmid-borne DNA insert restored resistance to methyl methanesulfonate and UV irradiation, as well as recombination proficiency when measured by Hfr-mediated conjugation. The cyanobacterial recA gene restored spontaneous but not mitomycin C-induced prophage production. Restriction analysis and subcloning yielded a 1.5-kilobase-pair Sau3A fragment which also restored methylmethane sulfonate resistance and coded for a 38- to 40-kilodalton polypeptide when expressed in an in vitro transcription-translation system.

  12. Growth and biopigment accumulation of cyanobacterium Spirulina platensis at different light intensities and temperature

    PubMed Central

    Kumar, Manoj; Kulshreshtha, Jyoti; Singh, Gajendra Pal

    2011-01-01

    In order to find out optimum culture condition for algal growth, the effect of light irradiance and temperature on growth rate, biomass composition and pigment production of Spirulina platensis were studied in axenic batch cultures. Growth kinetics of cultures showed a wide range of temperature tolerance from 20 °C to 40 °C. Maximum growth rate, cell production with maximum accumulation of chlorophyll and phycobilliproteins were found at temperature 35 °C and 2,000 lux light intensity. But with further increase in temperature and light intensity, reduction in growth rate was observed. Carotenoid content was found maximum at 3,500 lux. Improvement in the carotenoid content with increase in light intensity is an adaptive mechanism of cyanobacterium S.platensis for photoprotection, could be a good basis for the exploitation of microalgae as a source of biopigments. PMID:24031731

  13. Genetic transformation of marine cyanobacterium Synechococcus sp. CC9311 (Cyanophyceae) by electroporation

    NASA Astrophysics Data System (ADS)

    Chen, Huaxin; Lin, Hanzhi; Jiang, Peng; Li, Fuchao; Qin, Song

    2013-03-01

    Synechococcus sp. CC9311 is a marine cyanobacterium characterized by type IV chromatic acclimation (CA). A genetic transformation system was developed as a first step to elucidate the molecular mechanism of CA. The results show that Synechococcus sp. CC9311 cells were sensitive to four commonly used antibiotics: ampicillin, kanamycin, spectinomycin, and chloramphenicol. An integrative plasmid to disrupt the putative phycoerythrin lyase gene mpeV, using a kanamycin resistance gene as selectable marker, was constructed by recombinant polymerase chain reaction. The plasmid was then transformed into Synechococcus sp. CC9311 via electroporation. High transformation efficiency was achieved at a field strength of 2 kV/cm. DNA analysis showed that mpeV was fully disrupted following challenge of the transformants with a high concentration of kanamycin. In addition, the transformants that displayed poor growth on agar SN medium could be successfully plated on agarose SN medium.

  14. Metabolomic analysis of NAD kinase-deficient mutants of the cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Ishikawa, Yuuma; Miyagi, Atsuko; Haishima, Yuto; Ishikawa, Toshiki; Nagano, Minoru; Yamaguchi, Masatoshi; Hihara, Yukako; Kawai-Yamada, Maki

    2016-10-20

    NAD kinase (NADK) phosphorylates NAD(H) to NADP(H). The enzyme has a crucial role in the regulation of the NADP(H)/NAD(H) ratio in various organisms. The unicellular cyanobacterium Synechocystis sp. PCC 6803 possesses two NADK-encoding genes, sll1415 and slr0400. To elucidate the metabolic change in NADK-deficient mutants growing under photoautotrophic conditions, we conducted metabolomic analysis using capillary electrophoresis mass spectrometry (CE-MS). The growth curves of the wild-type parent (WT) and NADK-deficient mutants (Δ1415 and Δ0400) did not show any differences under photoautotrophic conditions. The NAD(P)(H) balance showed abnormality in both mutants. However, only the metabolite pattern of Δ0400 showed differences compared to WT. These results indicated that the two NADK isoforms have distinct functions in cyanobacterial metabolism. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. Sll1783, a monooxygenase associated with polysaccharide processing in the unicellular cyanobacterium Synechocystis PCC 6803.

    PubMed

    Miranda, Hélder; Immerzeel, Peter; Gerber, Lorenz; Hörnaeus, Katarina; Lind, Sara Bergström; Pattanaik, Bagmi; Lindberg, Pia; Mamedov, Fikret; Lindblad, Peter

    2017-10-01

    Cyanobacteria play a pivotal role as the primary producer in many aquatic ecosystems. The knowledge on the interacting processes of cyanobacteria with its environment - abiotic and biotic factors - is still very limited. Many potential exocytoplasmic proteins in the model unicellular cyanobacterium Synechocystis PCC 6803 have unknown functions and their study is essential to improve our understanding of this photosynthetic organism and its potential for biotechnology use. Here we characterize a deletion mutant of Synechocystis PCC 6803, Δsll1783, a strain that showed a remarkably high light resistance which is related with its lower thylakoid membrane formation. Our results suggests Sll1783 to be involved in a mechanism of polysaccharide degradation and uptake and we hypothesize it might function as a sensor for cell density in cyanobacterial cultures. © 2017 Scandinavian Plant Physiology Society.

  16. ADP-ribosylation of glutamine synthetase in the cyanobacterium Synechocystis sp. strain PCC 6803.

    PubMed Central

    Silman, N J; Carr, N G; Mann, N H

    1995-01-01

    Glutamine synthetase (GS) inactivation was observed in crude cell extracts and in the high-speed supernatant fraction from the cyanobacterium Synechocystis sp. strain PCC 6803 following the addition of ammonium ions, glutamine, or glutamate. Dialysis of the high-speed supernatant resulted in loss of inactivation activity, but this could be restored by the addition of NADH, NADPH, or NADP+ and, to a lesser extent, NAD+, suggesting that inactivation of GS involved ADP-ribosylation. This form of modification was confirmed both by labelling experiments using [32P]NAD+ and by chemical analysis of the hydrolyzed enzyme. Three different forms of GS, exhibiting no activity, biosynthetic activity only, or transferase activity only, could be resolved by chromatography, and the differences in activity were correlated with the extent of the modification. Both biosynthetic and transferase activities were restored to the completely inactive form of GS by treatment with phosphodiesterase. PMID:7768863

  17. Ammonia triggers photodamage of photosystem II in the cyanobacterium Synechocystis sp. strain PCC 6803.

    PubMed

    Drath, Miriam; Kloft, Nicole; Batschauer, Alfred; Marin, Kay; Novak, Jens; Forchhammer, Karl

    2008-05-01

    Ammonia has long been known to be toxic for many photosynthetic organisms; however, the target for its toxicity remains elusive. Here, we show that in the cyanobacterium Synechocystis sp. strain PCC 6803, ammonia triggers a rapid photodamage of photosystem II (PSII). Whereas wild-type cells can cope with this damage by turning on the FtsH2-dependent PSII repair cycle, the FtsH2-deficient mutant is highly sensitive and loses PSII activity at millimolar concentration of ammonia. Ammonia-triggered PSII destruction is light dependent and occurs already at low photon fluence rates. Experiments with monochromatic light showed that ammonia-promoted PSII photoinhibition is executed by wavebands known to directly destroy the manganese cluster in the PSII oxygen-evolving complex, suggesting that the oxygen-evolving complex may be a direct target for ammonia toxicity.

  18. ADP-ribosylation of glutamine synthetase in the cyanobacterium Synechocystis sp. strain PCC 6803.

    PubMed

    Silman, N J; Carr, N G; Mann, N H

    1995-06-01

    Glutamine synthetase (GS) inactivation was observed in crude cell extracts and in the high-speed supernatant fraction from the cyanobacterium Synechocystis sp. strain PCC 6803 following the addition of ammonium ions, glutamine, or glutamate. Dialysis of the high-speed supernatant resulted in loss of inactivation activity, but this could be restored by the addition of NADH, NADPH, or NADP+ and, to a lesser extent, NAD+, suggesting that inactivation of GS involved ADP-ribosylation. This form of modification was confirmed both by labelling experiments using [32P]NAD+ and by chemical analysis of the hydrolyzed enzyme. Three different forms of GS, exhibiting no activity, biosynthetic activity only, or transferase activity only, could be resolved by chromatography, and the differences in activity were correlated with the extent of the modification. Both biosynthetic and transferase activities were restored to the completely inactive form of GS by treatment with phosphodiesterase.

  19. Ammonia Triggers Photodamage of Photosystem II in the Cyanobacterium Synechocystis sp. Strain PCC 68031[OA

    PubMed Central

    Drath, Miriam; Kloft, Nicole; Batschauer, Alfred; Marin, Kay; Novak, Jens; Forchhammer, Karl

    2008-01-01

    Ammonia has long been known to be toxic for many photosynthetic organisms; however, the target for its toxicity remains elusive. Here, we show that in the cyanobacterium Synechocystis sp. strain PCC 6803, ammonia triggers a rapid photodamage of photosystem II (PSII). Whereas wild-type cells can cope with this damage by turning on the FtsH2-dependent PSII repair cycle, the FtsH2-deficient mutant is highly sensitive and loses PSII activity at millimolar concentration of ammonia. Ammonia-triggered PSII destruction is light dependent and occurs already at low photon fluence rates. Experiments with monochromatic light showed that ammonia-promoted PSII photoinhibition is executed by wavebands known to directly destroy the manganese cluster in the PSII oxygen-evolving complex, suggesting that the oxygen-evolving complex may be a direct target for ammonia toxicity. PMID:18322144

  20. Cytochrome c-553 is not required for photosynthetic activity in the cyanobacterium Synechococcus.

    PubMed Central

    Laudenbach, D E; Herbert, S K; McDowell, C; Fork, D C; Grossman, A R; Straus, N A

    1990-01-01

    In cyanobacteria, the water-soluble cytochrome c-553 functions as a mobile carrier of electrons between the membrane-bound cytochrome b6-f complex and P-700 reaction centers of Photosystem I. The structural gene for cytochrome c-553 (designated cytA) of the cyanobacterium Synechococcus sp. PCC 7942 was cloned, and the deduced amino acid sequence was shown to be similar to known cyanobacterial cytochrome c-553 proteins. A deletion mutant was constructed that had no detectable cytochrome c-553 based on spectral analyses and tetramethylbenzidine-hydrogen peroxide staining of proteins resolved by polyacrylamide gel electrophoresis. The mutant strain was not impaired in overall photosynthetic activity. However, this mutant exhibited a decreased efficiency of cytochrome f oxidation. These results indicate that cytochrome c-553 is not an absolute requirement for reducing Photosystem I reaction centers in Synechococcus sp. PCC 7942. PMID:1967057

  1. Elementary Economics: A Bibliography.

    ERIC Educational Resources Information Center

    Federal Reserve Bank of Chicago, IL.

    Elementary educators have realized in recent years the life-long importance of developing students' economic decision-making skills. Many now include economic education in the curriculum. This annotated bibliography was developed to support and encourage these efforts and to bring to educators' attention some of the excellent materials available…

  2. Temporal Gene Expression of the Cyanobacterium Arthrospira in Response to Gamma Rays.

    PubMed

    Badri, Hanène; Monsieurs, Pieter; Coninx, Ilse; Nauts, Robin; Wattiez, Ruddy; Leys, Natalie

    2015-01-01

    The edible cyanobacterium Arthrospira is resistant to ionising radiation. The cellular mechanisms underlying this radiation resistance are, however, still largely unknown. Therefore, additional molecular analysis was performed to investigate how these cells can escape from, protect against, or repair the radiation damage. Arthrospira cells were shortly exposed to different doses of 60Co gamma rays and the dynamic response was investigated by monitoring its gene expression and cell physiology at different time points after irradiation. The results revealed a fast switch from an active growth state to a kind of 'survival modus' during which the cells put photosynthesis, carbon and nitrogen assimilation on hold and activate pathways for cellular protection, detoxification, and repair. The higher the radiation dose, the more pronounced this global emergency response is expressed. Genes repressed during early response, suggested a reduction of photosystem II and I activity and reduced tricarboxylic acid (TCA) and Calvin-Benson-Bassham (CBB) cycles, combined with an activation of the pentose phosphate pathway (PPP). For reactive oxygen species detoxification and restoration of the redox balance in Arthrospira cells, the results suggested a powerful contribution of the antioxidant molecule glutathione. The repair mechanisms of Arthrospira cells that were immediately switched on, involve mainly proteases for damaged protein removal, single strand DNA repair and restriction modification systems, while recA was not induced. Additionally, the exposed cells showed significant increased expression of arh genes, coding for a novel group of protein of unknown function, also seen in our previous irradiation studies. This observation confirms our hypothesis that arh genes are key elements in radiation resistance of Arthrospira, requiring further investigation. This study provides new insights into phasic response and the cellular pathways involved in the radiation resistance of

  3. Cellular responses and bioremoval of nonylphenol by the bloom-forming cyanobacterium Planktothrix agardhii 1113

    NASA Astrophysics Data System (ADS)

    Medvedeva, Nadezda; Zaytseva, Tatyana; Kuzikova, Irina

    2017-07-01

    Nonylphenol (NP) is extensively used in agricultural, industrial and household applications. Moreover, NP is the major breakdown product of the nonionic surfactants, nonylphenol ethoxylates (NPEOs), the most widely used group of surfactants. Nonylphenol is persistent in the environment, highly toxic to aquatic organisms and is a potential endocrine disruptor. NP and NPEOs have been identified as priority hazardous substances under the Environmental Quality Standards Directive 2013/39/EU and are referred to in the list of substances of particular risk to the Baltic Sea. The toxicity of NP to the bloom-forming cyanobacterium Planktothrix agardhii 1113 isolated from the eastern Gulf of Finland, Baltic Sea and the bioremoval of NP by P. agardhii were studied. NP in concentrations > 0.4 mg L- 1 suppressed cyanobacterial growth. The median effective concentration of NP for P. agardhii after 4 days of treatment (EC50) was 1.5 mg L- 1. The removal of NP from the culture medium was primarily due to abiotic processes and biodegradation by the cyanobacterium rather than sorption by the cells. NP significantly increased the photosynthetic pigments, extracellular proteins and soluble exopolysaccharides content. The cyanobacterial growth inhibition was accompanied by the increased synthesis of microcystin dm-RR and of the odorous metabolites, geosmin and 2-methylisoborneol (MIB), by P. agardhii 1113. NP also notably increased the microcystin released into the environment. Increased levels of extracellular proteins, soluble exopolysaccharides, microcystins and odorous metabolites may affect the microbial loop in aquatic ecosystems. An increased level of malondialdehyde (MDA) was indicative of the formation of free radicals in P. agardhii under NP stress, whereas increased levels of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and proline indicated the occurrence of a scavenging mechanism.

  4. Temporal Gene Expression of the Cyanobacterium Arthrospira in Response to Gamma Rays

    PubMed Central

    Badri, Hanène; Monsieurs, Pieter; Coninx, Ilse; Nauts, Robin; Wattiez, Ruddy; Leys, Natalie

    2015-01-01

    The edible cyanobacterium Arthrospira is resistant to ionising radiation. The cellular mechanisms underlying this radiation resistance are, however, still largely unknown. Therefore, additional molecular analysis was performed to investigate how these cells can escape from, protect against, or repair the radiation damage. Arthrospira cells were shortly exposed to different doses of 60Co gamma rays and the dynamic response was investigated by monitoring its gene expression and cell physiology at different time points after irradiation. The results revealed a fast switch from an active growth state to a kind of 'survival modus' during which the cells put photosynthesis, carbon and nitrogen assimilation on hold and activate pathways for cellular protection, detoxification, and repair. The higher the radiation dose, the more pronounced this global emergency response is expressed. Genes repressed during early response, suggested a reduction of photosystem II and I activity and reduced tricarboxylic acid (TCA) and Calvin-Benson-Bassham (CBB) cycles, combined with an activation of the pentose phosphate pathway (PPP). For reactive oxygen species detoxification and restoration of the redox balance in Arthrospira cells, the results suggested a powerful contribution of the antioxidant molecule glutathione. The repair mechanisms of Arthrospira cells that were immediately switched on, involve mainly proteases for damaged protein removal, single strand DNA repair and restriction modification systems, while recA was not induced. Additionally, the exposed cells showed significant increased expression of arh genes, coding for a novel group of protein of unknown function, also seen in our previous irradiation studies. This observation confirms our hypothesis that arh genes are key elements in radiation resistance of Arthrospira, requiring further investigation. This study provides new insights into phasic response and the cellular pathways involved in the radiation resistance of

  5. Introducing Economics.

    ERIC Educational Resources Information Center

    Federal Reserve Bank of Boston, MA.

    The booklet outlines and presents examples of basic economics concepts. Objectives are to help elementary and secondary teachers introduce economic concepts in the classroom and to help teachers grasp some of the fundamentals of economics. The document is divided into seven sections. Each section presents concepts, offers three supporting…

  6. Economic Socialization.

    ERIC Educational Resources Information Center

    Armento, Beverly

    This paper identifies economic roles in terms of personal and social contexts and defines economic socialization as a life-long, complex, interactional, and multi-disciplinary set of processes that involve the development of ideological beliefs about economic systems and individual roles within an economy. Socialization is influenced by…

  7. Television Economics.

    ERIC Educational Resources Information Center

    Owen, Bruce M.; And Others

    Intended as an introduction to the economics of commercial television for the general reader, this volume considers the theory and analytical basis of television and the policy implications of those economics. Part I considers the economics of television markets with particular attention of the determinants of viewer markets; the supply of…

  8. Stimulating Economics

    ERIC Educational Resources Information Center

    Banaian, King

    2009-01-01

    With the current economic slump possibly the deepest since the Great Depression, interest in the subject of macroeconomics has reignited, and the number of students majoring in economics has increased during the last two years. While this would appear to be good news for educators in the economics field, the profession is nervous about more than…

  9. Proteomic and metabolomic analyses reveal metabolic responses to 3-hydroxypropionic acid synthesized internally in cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Wang, Yunpeng; Chen, Lei; Zhang, Weiwen

    2016-01-01

    3-hydroxypropionic acid (3-HP) is an important platform chemical with a wide range of applications. In our previous study, the biosynthetic pathway of 3-HP was constructed and optimized in cyanobacterium Synechocystis sp. PCC 6803, which led to 3-HP production directly from CO2 at a level of 837.18 mg L(-1) (348.8 mg/g dry cell weight). As the production and accumulation of 3-HP in cells affect cellular metabolism, a better understanding of cellular responses to 3-HP synthesized internally in Synechocystis will be important for further increasing 3-HP productivity in cyanobacterial chassis. Using a engineered 3-HP-producing SM strain, in this study, the cellular responses to 3-HP internally produced were first determined using a quantitative iTRAQ-LC-MS/MS proteomics approach and a LC-MS-based targeted metabolomics. A total of 2264 unique proteins were identified, which represented about 63 % of all predicted protein in Synechocystis in the proteomic analysis; meanwhile intracellular abundance of 24 key metabolites was determined by a comparative metabolomic analysis of the 3-HP-producing strain SM and wild type. Among all identified proteins, 204 proteins were found up-regulated and 123 proteins were found down-regulated, respectively. The proteins related to oxidative phosphorylation, photosynthesis, ribosome, central carbon metabolism, two-component systems and ABC-type transporters were up-regulated, along with the abundance of 14 metabolites related to central metabolism. The results suggested that the supply of ATP and NADPH was increased significantly, and the precursor malonyl-CoA and acetyl-CoA may also be supplemented when 3-HP was produced at a high level in Synechocystis. Confirmation of proteomic and metabolomic results with RT-qPCR and gene-overexpression strains of selected genes was also conducted, and the overexpression of three transporter genes putatively involved in cobalt/nickel, manganese and phosphate transporting (i.e., sll0385, sll1598

  10. Comparative toxicity of bentazon and molinate on growth, photosynthetic pigments, photosynthesis, and respiration of the Portuguese ricefield cyanobacterium Nostoc muscorum.

    PubMed

    Galhano, Victor; Peixoto, Francisco; Gomes-Laranjo, José; Fernández-Valiente, Eduardo

    2010-04-01

    Bentazon and molinate are selective herbicides recommended for integrated weed management in rice. Their toxicity on growth and some biochemical and physiological parameters of Nostoc muscorum, an abundant cyanobacterium in Portuguese rice fields, was evaluated under laboratory conditions during time- and concentration-dependent exposure for 72 h. Results showed that toxic concentrations (0.75-2 mM) of both herbicides have pleiotropic effects on the cyanobacterium. Molinate was more toxic than bentazon to growth, respiration, chlorophyll-a, carotenoids, and phycobiliproteins contents. Protein content was increased by both herbicides although the effect was particularly evident with higher concentrations of molinate (1.5-2 mM). The herbicides had contrasting effects on carbohydrates content: molinate increased this organic fraction whereas bentazon decreased it. Photosynthesis and respiration were inhibited by both herbicides.

  11. Nitric oxide ameliorates the damaging effects of oxidative stress induced by iron deficiency in cyanobacterium Anabaena 7120.

    PubMed

    Kaushik, Manish Singh; Srivastava, Meenakshi; Srivastava, Alka; Singh, Anumeha; Mishra, Arun Kumar

    2016-11-01

    In cyanobacterium Anabaena 7120, iron deficiency leads to oxidative stress with unavoidable consequences. Nitric oxide reduces pigment damage and supported the growth of Anabaena 7120 in iron-deficient conditions. Elevation in nitric oxide accumulation and reduced superoxide radical production justified the role of nitric oxide in alleviating oxidative stress in iron deficiency. Increased activities of antioxidative enzymes and higher levels of ROS scavengers (ascorbate, glutathione and thiol) in iron deficiency were also observed in the presence of nitric oxide. Nitric oxide also supported the membrane integrity of Anabaena cells and reduces protein and DNA damage caused by oxidative stress induced by iron deficiency. Results suggested that nitric oxide alleviates the damaging effects of oxidative stress induced by iron deficiency in cyanobacterium Anabaena 7120.

  12. Draft Genome Assembly of the Bloom-Forming Cyanobacterium Nodularia spumigena Strain CENA596 in Shrimp Production Ponds

    PubMed Central

    Popin, Rafael Vicentini; Rigonato, Janaina; Abreu, Vinicius Augusto Carvalho; Andreote, Ana Paula Dini; Silveira, Savênia Bonoto; Odebrecht, Clarisse

    2016-01-01

    We report here the draft genome assembly of the brackish cyanobacterium Nodularia spumigena strain CENA596 isolated from a shrimp production pond in Rio Grande do Sul, Brazil. The draft genome consists of 291 contigs with a total size of 5,189,679 bp. Secondary metabolite annotations resulted in several predicted gene clusters, including those responsible for encoding the hepatotoxin nodularin. PMID:27284148

  13. Draft Genome Sequence of Microcystis aeruginosa NIES-98, a Non-Microcystin-Producing Cyanobacterium from Lake Kasumigaura, Japan

    PubMed Central

    Suzuki, Shigekatsu; Sano, Tomoharu; Tanabe, Yuuhiko; Nakajima, Nobuyoshi; Kawachi, Masanobu

    2016-01-01

    Microcystis aeruginosa is a well-known bloom-forming cyanobacterium. We newly sequenced the whole genome of M. aeruginosa NIES-98, which is a non-microcystin-producing strain isolated from Lake Kasumigaura, Japan. The genome contains approximately 5.0 Mbp, with an average G+C content of 42.41% and 5,140 predicted protein-coding genes. PMID:27834696

  14. Identification of the n-1 fatty acid as an antibacterial constituent from the edible freshwater cyanobacterium Nostoc verrucosum.

    PubMed

    Oku, Naoya; Yonejima, Kohsuke; Sugawa, Takao; Igarashi, Yasuhiro

    2014-01-01

    The cyanobacterium Nostoc verrucosum occurs in cool, clear streams and its gelatinous colonies, called "ashitsuki," have been eaten in ancient Japan. Its ethanolic extract was found to inhibit the growth of Gram-positive bacteria and activity-guided fractionation yielded an unusual n-1 fatty acid, (9Z,12Z)-9,12,15-hexadecatrienoic acid (1), as one of the active principles. It inhibited the growth of Staphylococcus aureus at MIC 64 μg/mL.

  15. Genome-scale modeling of light-driven reductant partitioning and carbon fluxes in diazotrophic unicellular cyanobacterium Cyanothece sp. ATCC 51142

    SciTech Connect

    Vu, Trang; Stolyar, Sergey; Pinchuk, Grigoriy E.; Hill, Eric A.; Kucek, Leo A.; Brown, Roslyn N.; Lipton, Mary S.; Osterman, Andrei L.; Fredrickson, Jim K.; Konopka, Allan; Beliaev, Alex S.; Reed, Jennifer L.

    2012-04-05

    Genome-scale metabolic models have proven useful for answering fundamental questions about metabolic capabilities of a variety of microorganisms, as well as informing their metabolic engineering. However, only a few models are available for oxygenic photosynthetic microorganisms, particularly in cyanobacteria in which photosynthetic and respiratory electron transport chains (ETC) share components. We addressed the complexity of cyanobacterial ETC by developing a genome-scale model for the diazotrophic cyanobacterium, Cyanothece sp. ATCC 51142. The resulting metabolic reconstruction, iCce806, consists of 806 genes associated with 667 metabolic reactions and includes a detailed representation of the ETC and a biomass equation based on experimental measurements. Both computational and experimental approaches were used to investigate light-driven metabolism in Cyanothece sp. ATCC 51142, with a particular focus on reductant production and partitioning within the ETC. The simulation results suggest that growth and metabolic flux distributions are substantially impacted by the relative amounts of light going into the individual photosystems. When photosystem II flux is high, terminal oxidases of respiratory electron transport are predicted to be an important mechanism for removing excess electrons. When photosystem I flux is high cyclic electron transport becomes important. Model predictions of growth rates were in good quantitative agreement with measured growth rates, and predictions of reaction usage were qualitatively consistent with protein and mRNA expression data, when these latter datasets were used to constrain the model.

  16. Genome-Scale Modeling of Light-Driven Reductant Partitioning and Carbon Fluxes in Diazotrophic Unicellular Cyanobacterium Cyanothece sp. ATCC 51142

    SciTech Connect

    Vu, Trang; Stolyar, Sergey; Pinchuk, Grigoriy E.; Hill, Eric A.; Kucek, Leo A.; Brown, Roslyn N.; Lipton, Mary S.; Osterman, Andrei L.; Fredrickson, Jim K.; Konopka, Allan; Beliaev, Alex S.; Reed, Jennifer L.

    2012-04-05

    Genome-scale metabolic models have proven useful for answering fundamental questions about metabolic capabilities of a variety of microorganisms, as well as informing their metabolic engineering. However, only a few models are available for oxygenic photosynthetic microorganisms, particularly in cyanobacteria in which photosynthetic and respiratory electron transport chains (ETC) share components. We addressed the complexity of cyanobacterial ETC by developing a genome-scale model for the diazotrophic cyanobacterium, Cyanothece sp. ATCC 51142. The resulting metabolic reconstruction, iCce806, consists of 806 genes associated with 667 metabolic reactions and includes a detailed representation of the ETC and a biomass equation based on experimental measurements. Both computational and experimental approaches were used to investigate light-driven metabolism in Cyanothece sp. ATCC 51142, with a particular focus on reductant production and partitioning within the ETC. The simulation results suggest that growth and metabolic flux distributions are substantially impacted by the relative amounts of light going into the individual photosystems. When photosystem II flux is high, terminal oxidases of respiratory electron transport are predicted to be an important mechanism for removing excess electrons. When photosystem I flux is high cyclic electron transport becomes important. Model predictions of growth rates were in good quantitative agreement with measured growth rates, and predictions of reaction usage were ualitatively consistent with protein and mRNA expression data, when these latter datasets were used to constrain the model.

  17. Responses of a rice-field cyanobacterium Anabaena siamensis TISTR-8012 upon exposure to PAR and UV radiation.

    PubMed

    Rastogi, Rajesh P; Incharoensakdi, Aran; Madamwar, Datta

    2014-10-15

    The effects of PAR and UV radiation and subsequent responses of certain antioxidant enzymatic and non-enzymatic defense systems were studied in a rice field cyanobacterium Anabaena siamensis TISTR 8012. UV radiation resulted in a decline in growth accompanied by a decrease in chlorophyll a and photosynthetic efficiency. Exposure of cells to UV radiation significantly affected the differentiation of vegetative cells into heterocysts or akinetes. UV-B radiation caused the fragmentation of the cyanobacterial filaments conceivably due to the observed oxidative stress. A significant increase of reactive oxygen species in vivo and DNA strand breaks were observed in UV-B exposed cells followed by those under UV-A and PAR radiation, respectively. The UV-induced oxidative damage was alleviated due to an induction of antioxidant enzymatic/non-enzymatic defense systems. In response to UV irradiation, the studied cyanobacterium exhibited a significant increase in antioxidative enzyme activities of superoxide dismutase, catalase and peroxidase. Moreover, the cyanobacterium also synthesized some UV-absorbing/screening substances. HPLC coupled with a PDA detector revealed the presence of three compounds with UV-absorption maxima at 326, 331 and 345 nm. The induction of the biosynthesis of these UV-absorbing compounds was found under both PAR and UV radiation, thus suggesting their possible function as an active photoprotectant.

  18. Effects of Cylindrospermopsin Producing Cyanobacterium and Its Crude Extracts on a Benthic Green Alga—Competition or Allelopathy?

    PubMed Central

    B-Béres, Viktória; Vasas, Gábor; Dobronoki, Dalma; Gonda, Sándor; Nagy, Sándor Alex; Bácsi, István

    2015-01-01

    Cylindrospermopsin (CYN) is a toxic secondary metabolite produced by filamentous cyanobacteria which could work as an allelopathic substance, although its ecological role in cyanobacterial-algal assemblages is mostly unclear. The competition between the CYN-producing cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum, and the benthic green alga Chlorococcum sp. was investigated in mixed cultures, and the effects of CYN-containing cyanobacterial crude extract on Chlorococcum sp. were tested by treatments with crude extracts containing total cell debris, and with cell debris free crude extracts, modelling the collapse of a cyanobacterial water bloom. The growth inhibition of Chlorococcum sp. increased with the increasing ratio of the cyanobacterium in mixed cultures (inhibition ranged from 26% to 87% compared to control). Interestingly, inhibition of the cyanobacterium growth also occurred in mixed cultures, and it was more pronounced than it was expected. The inhibitory effects of cyanobacterial crude extracts on Chlorococcum cultures were concentration-dependent. The presence of C. ovalisporum in mixed cultures did not cause significant differences in nutrient content compared to Chlorococcum control culture, so the growth inhibition of the green alga could be linked to the presence of CYN and/or other bioactive compounds. PMID:26528991

  19. Effects of Cylindrospermopsin Producing Cyanobacterium and Its Crude Extracts on a Benthic Green Alga-Competition or Allelopathy?

    PubMed

    B-Béres, Viktória; Vasas, Gábor; Dobronoki, Dalma; Gonda, Sándor; Nagy, Sándor Alex; Bácsi, István

    2015-10-30

    Cylindrospermopsin (CYN) is a toxic secondary metabolite produced by filamentous cyanobacteria which could work as an allelopathic substance, although its ecological role in cyanobacterial-algal assemblages is mostly unclear. The competition between the CYN-producing cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum, and the benthic green alga Chlorococcum sp. was investigated in mixed cultures, and the effects of CYN-containing cyanobacterial crude extract on Chlorococcum sp. were tested by treatments with crude extracts containing total cell debris, and with cell debris free crude extracts, modelling the collapse of a cyanobacterial water bloom. The growth inhibition of Chlorococcum sp. increased with the increasing ratio of the cyanobacterium in mixed cultures (inhibition ranged from 26% to 87% compared to control). Interestingly, inhibition of the cyanobacterium growth also occurred in mixed cultures, and it was more pronounced than it was expected. The inhibitory effects of cyanobacterial crude extracts on Chlorococcum cultures were concentration-dependent. The presence of C. ovalisporum in mixed cultures did not cause significant differences in nutrient content compared to Chlorococcum control culture, so the growth inhibition of the green alga could be linked to the presence of CYN and/or other bioactive compounds.

  20. Behavioral Economics

    PubMed Central

    Reed, Derek D.; Niileksela, Christopher R.; Kaplan, Brent A.

    2013-01-01

    In recent years, behavioral economics has gained much attention in psychology and public policy. Despite increased interest and continued basic experimental studies, the application of behavioral economics to therapeutic settings remains relatively sparse. Using examples from both basic and applied studies, we provide an overview of the principles comprising behavioral economic perspectives and discuss implications for behavior analysts in practice. A call for further translational research is provided. PMID:25729506

  1. De novo assembly and characterization of the floral transcriptome of an economically important tree species, Lindera glauca (Lauraceae), including the development of EST-SSR markers for population genetics.

    PubMed

    Zhu, Shanshan; Ding, Yanqian; Yap, Zhaoyan; Qiu, Yingxiong

    2016-11-01

    Lindera glauca (Lauraceae) is an economically important East Asian forest tree characterized by a dioecy in China and apomixis in Japan. However, patterns of population genetic diversity and structure of this species remain unknown for this species due to a lack of efficient molecular markers. In this study, we employed Illumina sequencing to analyze the transcriptomes of the female and male flower buds of L. glauca. We retrieved 59,753 and 75,075 unigenes for the female and male buds, respectively. Based on sequence similarity, 44,379 (74.27 %) unigenes for the female and 45,414 (60.49 %) unigenes for the male were matched to public databases. We identified 11,127 putative differentially expressed genes between the female and male buds and 20,048 expressed sequence tag-simple sequence repeats (EST-SSRs). From 3147 primer pairs designed successfully, 120 were selected for validation of polymorphism, and 13 could reliably amplify polymorphic bands and exhibited moderate levels of genetic diversity (e.g., N A = 4.42; H E = 0.56) when surveyed across 96 individuals of altogether six L. glauca populations from China and Japan. One of the three population genetic clusters identified in China was fixed in Japan, suggesting a historical population bottleneck following island immigration. The present study has generated a wealth of transcriptome data for future functional genomic research focused on the variable reproductive system of L. glauca (dioecy, apomixis) as well as EST-SSR markers for population genetics studies and its intriguing evolutionary shift from dioecy to apomixis in the wake of island colonization.

  2. Molecular exploration of the highly radiation resistant cyanobacterium Arthrospira sp. PCC 8005

    NASA Astrophysics Data System (ADS)

    Badri, Hanène; Leys, Natalie; Wattiez, Ruddy

    Arthrospira (Spirulina) is a photosynthetic cyanobacterium able to use sunlight to release oxygen from water and remove carbon dioxide and nitrate from water. In addition, it is suited for human consumption (edible). For these traits, the cyanobacterium Arthrospira sp. PCC 8005 was selected by the European Space Agency (ESA) as part of the life support system MELiSSA for recycling oxygen, water, and food during future long-haul space missions. However, during such extended missions, Arthrospira sp. PCC 8005 will be exposed to continuous artificial illumination and harmful cosmic radiation. The aim of this study was to investigate how Arthrospira will react and behave when exposed to such stress environment. The cyanobacterium Arthrospira sp. PCC 8005 was exposed to high gamma rays doses in order to unravel in details the response of this bacterium following such stress. Test results showed that after acute exposure to high doses of 60Co gamma radiation upto 3200 Gy, Arthrospira filaments were still able to restart photosynthesis and proliferate normally. Doses above 3200 Gy, did have a detrimental effect on the cells, and delayed post-irradiation proliferation. The photosystem activity, measured as the PSII quantum yield immediately after irradiation, decreased significantly at radiation doses above 3200 Gy. Likewise through pigment content analysis a significant decrease in phycocyanin was observed following exposure to 3200 Gy. The high tolerance of this bacterium to 60Co gamma rays (i.e. ca. 1000x more resistant than human cells for example) raised our interest to investigate in details the cellular and molecular mechanisms behind this amazing resistance. Optimised DNA, RNA and protein extraction methods and a new microarray chip specific for Arthrospira sp. PCC 8005 were developed to identify the global cellular and molecular response following exposure to 3200 Gy and 5000 Gy A total of 15,29 % and 30,18 % genes were found differentially expressed in RNA

  3. Lab-Scale Study of the Calcium Carbonate Dissolution and Deposition by Marine Cyanobacterium Phormidium subcapitatum

    NASA Technical Reports Server (NTRS)

    Karakis, S. G.; Dragoeva, E. G.; Lavrenyuk, T. I.; Rogochiy, A.; Gerasimenko, L. M.; McKay, D. S.; Brown, I. I.

    2006-01-01

    Suggestions that calcification in marine organisms changes in response to global variations in seawater chemistry continue to be advanced (Wilkinson, 1979; Degens et al. 1985; Kazmierczak et al. 1986; R. Riding 1992). However, the effect of [Na+] on calcification in marine cyanobacteria has not been discussed in detail although [Na+] fluctuations reflect both temperature and sea-level fluctuations. The goal of these lab-scale studies therefore was to study the effect of environmental pH and [Na+] on CaCO3 deposition and dissolution by marine cyanobacterium Phormidium subcapitatum. Marine cyanobacterium P. subcapitatum has been cultivated in ASN-III medium. [Ca2+] fluctuations were monitored with Ca(2+) probe. Na(+) concentrations were determined by the initial solution chemistry. It was found that the balance between CaCO3 dissolution and precipitation induced by P. subcapitatum grown in neutral ASN III medium is very close to zero. No CaCO3 precipitation induced by cyanobacterial growth occurred. Growth of P. subcapitatum in alkaline ASN III medium, however, was accompanied by significant oscillations in free Ca(2+) concentration within a Na(+) concentration range of 50-400 mM. Calcium carbonate precipitation occurred during the log phase of P. subcapitatum growth while carbonate dissolution was typical for the stationary phase of P. subcapitatum growth. The highest CaCO3 deposition was observed in the range of Na(+) concentrations between 200-400 mM. Alkaline pH also induced the clamping of P. subcapitatum filaments, which appeared to have a strong affinity to envelop particles of chemically deposited CaCO3 followed by enlargement of those particles size. EDS analysis revealed the presence of Mg-rich carbonate (or magnesium calcite) in the solution containing 10-100 mM Na(+); calcite in the solution containing 200 mM Na(+); and aragonite in the solution containing with 400 mM Na(+). Typical present-day seawater contains xxmM Na(+). Early (Archean) seawater was

  4. Specific Glucoside Transporters Influence Septal Structure and Function in the Filamentous, Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120.

    PubMed

    Nieves-Morión, Mercedes; Lechno-Yossef, Sigal; López-Igual, Rocío; Frías, José E; Mariscal, Vicente; Nürnberg, Dennis J; Mullineaux, Conrad W; Wolk, C Peter; Flores, Enrique

    2017-04-01

    When deprived of combined nitrogen, some filamentous cyanobacteria contain two cell types: vegetative cells that fix CO2 through oxygenic photosynthesis and heterocysts that are specialized in N2 fixation. In the diazotrophic filament, the vegetative cells provide the heterocysts with reduced carbon (mainly in the form of sucrose) and heterocysts provide the vegetative cells with combined nitrogen. Septal junctions traverse peptidoglycan through structures known as nanopores and appear to mediate intercellular molecular transfer that can be traced with fluorescent markers, including the sucrose analog esculin (a coumarin glucoside) that is incorporated into the cells. Uptake of esculin by the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 was inhibited by the α-glucosides sucrose and maltose. Analysis of Anabaena mutants identified components of three glucoside transporters that move esculin into the cells: GlsC (Alr4781) and GlsP (All0261) are an ATP-binding subunit and a permease subunit of two different ABC transporters, respectively, and HepP (All1711) is a major facilitator superfamily (MFS) protein that was shown previously to be involved in formation of the heterocyst envelope. Transfer of fluorescent markers (especially calcein) between vegetative cells of Anabaena was impaired by mutation of glucoside transporter genes. GlsP and HepP interact in bacterial two-hybrid assays with the septal junction-related protein SepJ, and GlsC was found to be necessary for the formation of a normal number of septal peptidoglycan nanopores and for normal subcellular localization of SepJ. Therefore, beyond their possible role in nutrient uptake in Anabaena, glucoside transporters influence the structure and function of septal junctions.IMPORTANCE Heterocyst-forming cyanobacteria have the ability to perform oxygenic photosynthesis and to assimilate atmospheric CO2 and N2 These organisms grow as filaments that fix these gases specifically in vegetative

  5. Specific Glucoside Transporters Influence Septal Structure and Function in the Filamentous, Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120

    PubMed Central

    Nieves-Morión, Mercedes; Lechno-Yossef, Sigal; López-Igual, Rocío; Frías, José E.; Mariscal, Vicente; Nürnberg, Dennis J.; Mullineaux, Conrad W.; Wolk, C. Peter

    2017-01-01

    ABSTRACT When deprived of combined nitrogen, some filamentous cyanobacteria contain two cell types: vegetative cells that fix CO2 through oxygenic photosynthesis and heterocysts that are specialized in N2 fixation. In the diazotrophic filament, the vegetative cells provide the heterocysts with reduced carbon (mainly in the form of sucrose) and heterocysts provide the vegetative cells with combined nitrogen. Septal junctions traverse peptidoglycan through structures known as nanopores and appear to mediate intercellular molecular transfer that can be traced with fluorescent markers, including the sucrose analog esculin (a coumarin glucoside) that is incorporated into the cells. Uptake of esculin by the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 was inhibited by the α-glucosides sucrose and maltose. Analysis of Anabaena mutants identified components of three glucoside transporters that move esculin into the cells: GlsC (Alr4781) and GlsP (All0261) are an ATP-binding subunit and a permease subunit of two different ABC transporters, respectively, and HepP (All1711) is a major facilitator superfamily (MFS) protein that was shown previously to be involved in formation of the heterocyst envelope. Transfer of fluorescent markers (especially calcein) between vegetative cells of Anabaena was impaired by mutation of glucoside transporter genes. GlsP and HepP interact in bacterial two-hybrid assays with the septal junction-related protein SepJ, and GlsC was found to be necessary for the formation of a normal number of septal peptidoglycan nanopores and for normal subcellular localization of SepJ. Therefore, beyond their possible role in nutrient uptake in Anabaena, glucoside transporters influence the structure and function of septal junctions. IMPORTANCE Heterocyst-forming cyanobacteria have the ability to perform oxygenic photosynthesis and to assimilate atmospheric CO2 and N2. These organisms grow as filaments that fix these gases specifically in

  6. Effects of cyanobacterium Fischerella ambigua isolates and cell free culture media on zebrafish (Danio rerio) embryo development.

    PubMed

    Wright, Anthony D; Papendorf, Olaf; König, Gabriele M; Oberemm, Axel

    2006-10-01

    The toxic effects of several species of fresh water cyanobacteria, notably Microcystis species and associated toxins, the microcystins, Anabaena species (anatoxin), Nodularia sp. (nodularin), and Cylindrospermopsis raciborskii (cylindrospermopsin), are well known. Little, however, is known about the effects of secondary metabolites other than alkaloids. Early life stage tests with zebrafish (Danio rerio) were used to detect bioactive properties of compounds released by healthy cyanobacteria (Fischerella ambigua), particularly on the early developmental stages of fish. This approach, using F. ambigua is probably most valuable as it shows the toxicity of healthy growing cyanobacteria. The effects of cyanobacterial secondary metabolites on the embryonic stages of fish are of considerable interest as many aquatic creatures, particularly fish, are unable to avoid the potential toxins that may be released by undesirable algal blooms or as a result of allelopathic effects. In the current study, the zebrafish (D. rerio) was used as a model experimental system to investigate the effects of ambigols A and C, tjipanazole D and C, 2,4-dichlorobenzoic acid, cell free culture media, and media extracts of a terrestrial/fresh water strain of the cyanobacterium F. ambigua on embryo development. Fish embryo tests performed with the cell free culture medium showed that after 3h of exposure to undiluted culture medium all fish embryos died. At a tenfold dilution the process of epiboly (formation of the gastrula) was retarded in all embryos, lesions were observed, and their general development was significantly arrested, finally followed by death. The same tests performed with extracts (dichloromethane, n-butanol, and residual cell free culture medium) of the cell free culture medium, ambigol A, ambigol C, 2,4-dichlorobenzoic acid and tjipanazole D showed only ambigol A to have an influence on zebrafish development at concentrations>or=1 mg/l (2.06 microM). After 55 h all embryos

  7. Proteomic Analysis of the Marine Cyanobacterium Synechococcus WH8102 and Implications for Estimates of the Cellular Iron Content

    NASA Astrophysics Data System (ADS)

    Saito, M. A.; Bertrand, E. M.; Bulygin, V.; Moran, D.; Waterbury, J. B.

    2008-12-01

    The proteome of the marine cyanobacterium Synechococcus WH8102 was analyzed by nanospray liquid chromatography mass spectrometry (nLC-MS) with two major goals: to provide a first examination of the relative abundance of the most abundant proteins in this important microbe and to provide the necessary mass spectra for future quantification of biogeochemically significant proteins. Analyses of 37 nLC-MS runs of whole cell tryptic digestions and SDS-PAGE gel separated tryptic digestions resulted in a total of 636 proteins identified, 376 identified with two or more tryptic peptides. The identifications used the Sequest algorithm with stringent data filters on 54003 observed peptides, 3066 of which were unique, with a false positive rate of 2.2%. These measured proteins represent ~ 25.2% (14.8% with >= 2 peptides) of the open reading frames (ORFs) in the genome, similar to or higher than the percentage found in other cyanobacterial proteome studies thus far. The relative abundance of the more abundant proteins in the proteome was examined using the exponentially modified protein abundance index from a single nLC-MS run that identified 372 proteins (14.7% of the ORFs) from 7743 observed peptides (1224 unique peptides). Estimates of the relative abundance showed the photosynthesis and respiration category contributing approximately 32% of the total detected protein, hypothetical proteins contributing about 16%, and translation about 12%. Of biogeochemical interest, multiple types of nitrogen assimilation systems were observed to be simultaneously expressed as proteins, only 5 of the 21 B12 biosynthesis proteins were identified likely due to low abundance, and the metalloproteins metallothionein and nickel superoxide dismutase were relatively abundant. In contrast to previous predictions of a high photosystem I: photosystem II ratio of approximately 3 in the cyanobacteria and a resultant high cellular iron content, the ratio of the average relative abundances of all

  8. Elucidation of Insertion Elements Carried on Plasmids and In Vitro Construction of Shuttle Vectors from the Toxic Cyanobacterium Planktothrix

    PubMed Central

    Christiansen, Guntram; Goesmann, Alexander

    2014-01-01

    Several gene clusters that are responsible for toxin synthesis in bloom-forming cyanobacteria have been found to be associated with transposable elements (TEs). In particular, insertion sequence (IS) elements were shown to play a role in the inactivation or recombination of the genes responsible for cyanotoxin synthesis. Plasmids have been considered important vectors of IS element distribution to the host. In this study, we aimed to elucidate the IS elements propagated on the plasmids and the chromosome of the toxic cyanobacterium Planktothrix agardhii NIVA-CYA126/8 by means of high-throughput sequencing. In total, five plasmids (pPA5.5, pPA14, pPA50, pPA79, and pPA115, of 5, 6, 50, 79, and 120 kbp, respectively) were elucidated, and two plasmids (pPA5.5, pPA115) were found to propagate full IS element copies. Large stretches of shared DNA information between plasmids were constituted of TEs. Two plasmids (pPA5.5, pPA14) were used as candidates to engineer shuttle vectors (named pPA5.5SV and pPA14SV, respectively) in vitro by PCR amplification and the subsequent transposition of the Tn5 cat transposon containing the R6Kγ origin of replication of Escherichia coli. While pPA5.5SV was found to be fully segregated, pPA14SV consistently co-occurred with its wild-type plasmid even under the highest selective pressure. Interestingly, the Tn5 cat transposon became transferred by homologous recombination into another plasmid, pPA50. The availability of shuttle vectors is considered to be of relevance in investigating genome plasticity as a consequence of homologous recombination events. Combining the potential of high-throughput sequencing and in vitro production of shuttle vectors makes it simple to produce species-specific shuttle vectors for many cultivable prokaryotes. PMID:24907328

  9. PSP toxin release from the cyanobacterium Raphidiopsis brookii D9 (Nostocales) can be induced by sodium and potassium ions.

    PubMed

    Soto-Liebe, Katia; Méndez, Marco A; Fuenzalida, Loreto; Krock, Bernd; Cembella, Allan; Vásquez, Mónica

    2012-12-01

    Paralytic shellfish poisoning (PSP) toxins are a group of naturally occurring neurotoxic alkaloids produced among several genera of primarily freshwater cyanobacteria and marine dinoflagellates. Although saxitoxin (STX) and analogs are all potent Na(+) channel blockers in vertebrate cells, the functional role of these compounds for the toxigenic microorganisms is unknown. Based upon the known importance of monovalent cations (such as sodium) in the maintenance of cellular homeostasis and ion channel function, we examined the effect of high extracellular concentrations of these ions on growth, cellular integrity, toxin production and release to the external medium in the filamentous freshwater cyanobacterium, Raphidiopsis brookii D9; a gonyautoxins (GTX2/3) and STX producing toxigenic strain. We observed a toxin export in response to high (17 mM) NaCl and KCl concentrations in the growth medium that was not primarily related to osmotic stress effects, compared to the osmolyte mannitol. Addition of exogenous PSP toxins with the same compositional profile as the one produced by R. brookii D9 was able to partially mitigate this effect of high Na⁺ (17 mM). The PSP toxin biosynthetic gene cluster (sxt) in D9 has two genes (sxtF and sxtM) that encode for a MATE (multidrug and toxic compound extrusion) transporter. This protein family, represented by NorM in the bacterium Vibrio parahaemolyticus, confers resistance to multiple cationic toxic agents through Na⁺/drug antiporters. Conserved domains for Na⁺ and drug recognition have been described in NorM. For the D9 sxt cluster, the Na⁺ recognition domain is conserved in both SxtF and SxtM, but the drug recognition domain differs between them. These results suggest that PSP toxins are exported directly in response to the presence of monovalent cations (Na⁺, K⁺) at least at elevated concentrations. Thus, the presence of both genes in the sxt cluster from strain D9 can be explained as a selective recognition

  10. Nebraska Home Economics Needs Assessment.

    ERIC Educational Resources Information Center

    Johnson, Julie M.

    An assessment of the needs of the economically disadvantaged measured the importance of specific home economics content for high school students. Mailed questionnaires were returned by 470 parents of economically and noneconomically disadvantaged students and representatives from the Nebraska Department of Social Services. The 136 concepts used in…

  11. [Growth and metabolite production of the marine cyanobacterium Synechococcus sp. (Chroococcales) in function to irradiance].

    PubMed

    Rosales-Loaiza, Néstor; Guevara, Miguel; Lodeiros, César; Morales, Ever

    2008-06-01

    Changes in salinity, temperature and irradiance during wet and dry seasons have induced metabolic versatility in cyanobacteria from saline environments. Cyanobacteria from these environments have biotechnological potential for the production of metabolites with pharmaceutical and industrial interest. We studied the growth, dry mass and metabolite production of the cyanobacterium Synechococcus sp. MOF-03 in function of irradiance (78, 156 and 234 micromol q m(-2) s(-1)). All batch cultures were maintained by triplicate in constant aeration, 12:12 h photoperiod, 30 +/- 2 degrees C and 35% per hundred. Maximum values of protein, carbohydrates and lipids, of 530.19 +/- 11.16, 408.94 +/- 4.27 and 56.20 +/- 1.17 microg ml(-1), respectively, were achieved at 78 micromol q m(-2) s(-1). Pigments, analyzed by HPLC, showed maximum values at 78 micromol q m(-2) s(-1) for chlorophyll a with 7.72 +/- 0.16 microg ml(-1), and at 234 micromol q m(-2) s(-1) for beta-carotene and zeaxanthin with 0.70 +/- 0.01 and 0.67 +/- 0.05 microg ml(-1). Chlorophyll a:beta-carotene ratio decreased from 17.15 to 6.91 at 78 and 234 micromol q m(-2) s(-'1); whereas beta-carotene:zeaxanthin ratio showed no changes between 78 and 156 micromol q m(-2) s(-1), around 1.21, and decreased at 234 micromol q m(-2) s(-1), to 1.04. Also, this cyanobacterium produced the greatest cell density and dry mass at 156 micromol q m(-2) s(-1), with 406.13 +/- 21.74 x l0(6) cell ml(-1) and 1.49 +/- 0.11 mg ml(-1), respectively. Exopolysaccharide production was stable between 156 y 234 micromol q m(-2) s(-1), around 110 microg ml(-1). This Synechococcus strain shows a great potential for the production of enriched biomass with high commercial value metabolites.

  12. Economic Stabilization Policies. Economic Topic Series.

    ERIC Educational Resources Information Center

    Lewis, Wilfred

    This pamphlet was derived from a discussion paper prepared for a Joint Council conference. It was specifically revised for this series to bring an important subject to the attention of students and concerned citizens. Part One defines the problem of economic stabilization and explains the fiscal and monetary measures used to help control the…

  13. Mutation of a Gene Encoding a Putative Glycoprotease Leads to Reduced Salt Tolerance, Altered Pigmentation, and Cyanophycin Accumulation in the Cyanobacterium Synechocystis sp. Strain PCC 6803

    PubMed Central

    Zuther, Ellen; Schubert, Hendrik; Hagemann, Martin

    1998-01-01

    The salt-sensitive mutant 549 of the cyanobacterium Synechocystis sp. strain PCC 6803 was genetically and physiologically characterized. The mutated site and corresponding wild-type site were cloned and partially sequenced. The genetic analysis revealed that during the mutation about 1.8 kb was deleted from the chromosome of mutant 549. This deletion affected four open reading frames: a gcp gene homolog, the psaFJ genes, and an unknown gene. After construction of mutants with single mutations, only the gcp mutant showed a reduction in salt tolerance comparable to that of the initial mutant, indicating that the deletion of this gene was responsible for the salt sensitivity and that the other genes were of minor importance. Besides the reduced salt tolerance, a remarkable change in pigmentation was observed that became more pronounced in salt-stressed cells. The phycobilipigment content decreased, and that of carotenoids increased. Investigations of changes in the ultrastructure revealed an increase in the amount of characteristic inclusion bodies containing the high-molecular-weight nitrogen storage polymer cyanophycin (polyaspartate and arginine). The salt-induced accumulation of cyanophycin was confirmed by chemical estimations. The putative glycoprotease encoded by the gcp gene might be responsible for the degradation of cyanophycin in Synechocystis. Mutation of this gene leads to nitrogen starvation of the cells, accompanied by characteristic changes in pigmentation, ultrastructure, and salt tolerance level. PMID:9537367

  14. Genome-Scale Modeling of Light-Driven Reductant Partitioning and Carbon Fluxes in Diazotrophic Unicellular Cyanobacterium Cyanothece sp. ATCC 51142

    PubMed Central

    Pinchuk, Grigoriy E.; Hill, Eric A.; Kucek, Leo A.; Brown, Roslyn N.; Lipton, Mary S.; Osterman, Andrei; Fredrickson, Jim K.; Konopka, Allan E.; Beliaev, Alexander S.; Reed, Jennifer L.

    2012-01-01

    Genome-scale metabolic models have proven useful for answering fundamental questions about metabolic capabilities of a variety of microorganisms, as well as informing their metabolic engineering. However, only a few models are available for oxygenic photosynthetic microorganisms, particularly in cyanobacteria in which photosynthetic and respiratory electron transport chains (ETC) share components. We addressed the complexity of cyanobacterial ETC by developing a genome-scale model for the diazotrophic cyanobacterium, Cyanothece sp. ATCC 51142. The resulting metabolic reconstruction, iCce806, consists of 806 genes associated with 667 metabolic reactions and includes a detailed representation of the ETC and a biomass equation based on experimental measurements. Both computational and experimental approaches were used to investigate light-driven metabolism in Cyanothece sp. ATCC 51142, with a particular focus on reductant production and partitioning within the ETC. The simulation results suggest that growth and metabolic flux distributions are substantially impacted by the relative amounts of light going into the individual photosystems. When growth is limited by the flux through photosystem I, terminal respiratory oxidases are predicted to be an important mechanism for removing excess reductant. Similarly, under photosystem II flux limitation, excess electron carriers must be removed via cyclic electron transport. Furthermore, in silico calculations were in good quantitative agreement with the measured growth rates whereas predictions of reaction usage were qualitatively consistent with protein and mRNA expression data, which we used to further improve the resolution of intracellular flux values. PMID:22529767

  15. PrpJ, a PP2C-type protein phosphatase located on the plasma membrane, is involved in heterocyst maturation in the cyanobacterium Anabaena sp. PCC 7120.

    PubMed

    Jang, Jichan; Wang, Li; Jeanjean, Robert; Zhang, Cheng-Cai

    2007-04-01

    Protein phosphatases play important roles in the regulation of cell growth, division and differentiation. The cyanobacterium Anabaena PCC 7120 is able to differentiate heterocysts specialized in nitrogen fixation. To protect the nitrogenase from inactivation by oxygen, heterocyst envelope possesses a layer of polysaccharide and a layer of glycolipids. In the present study, we characterized All1731 (PrpJ), a protein phosphatase from Anabaena PCC 7120. prpJ was constitutively expressed in both vegetative cells and heterocysts. Under diazotrophic conditions, the mutant DeltaprpJ (S20) did not grow, lacked only one of the two heterocyst glycolipids, and fragmented extensively at the junctions between developing cells and vegetative cells. No heterocyst glycolipid layer could be observed in the mutant by electron microscopy. The inactivation of prpJ affected the expression of hglE(A) and nifH, two genes necessary for the formation of the glycolipid layer of heterocysts and the nitrogenase respectively. PrpJ displayed a phosphatase activity characteristic of PP2C-type protein phosphatases, and was localized on the plasma membrane. The function of prpJ establishes a new control point for heterocyst maturation because it regulates the synthesis of only one of the two heterocyst glycolipids while all other genes so far analysed regulate the synthesis of both heterocyst glycolipids.

  16. The 5' untranslated region of the rbp1 mRNA is required for translation of its mRNA under low temperatures in the cyanobacterium Synechococcus elongatus.

    PubMed

    Hayashi, Rie; Sugita, Chieko; Sugita, Mamoru

    2017-01-01

    The unicellular cyanobacterium Synechococcus elongatus has three RNA-binding protein (Rbp) genes, rbp1, rbp2 and rbp3. The rbp1 gene was upregulated by cold treatment while rbp2 and rbp3 expression decreased remarkably after exposure to cold temperatures. To investigate the mechanism underlying cold-induced rbp1 expression, a series of rbp1-luxAB transcriptional fusion constructs were expressed in S. elongatus PCC 7942 under cold conditions. The results showed that the region from -33 to -3 of the transcription initiation site contains an essential sequence for basal transcription of the rbp1 gene and that the 120-bp region (-34 to -153) does not contain critical cis-elements required for cold-shock induction. In contrast, mutational analysis carrying the 5'-untranslated region (UTR) of rbp1-luxAB translational fusions indicated that the 5'-UTR of rbp1 plays an important role in cold induction of the rbp1 gene product. Taken together, we conclude that the cold induction of rbp1 may be regulated at a posttranscriptional level rather than at the transcriptional level.

  17. Molecular Cloning and Biochemical Characterization of the Iron Superoxide Dismutase from the Cyanobacterium Nostoc punctiforme ATCC 29133 and Its Response to Methyl Viologen-Induced Oxidative Stress.

    PubMed

    Moirangthem, Lakshmipyari Devi; Ibrahim, Kalibulla Syed; Vanlalsangi, Rebecca; Stensjö, Karin; Lindblad, Peter; Bhattacharya, Jyotirmoy

    2015-12-01

    Superoxide dismutase (SOD) detoxifies cell-toxic superoxide radicals and constitutes an important component of antioxidant machinery in aerobic organisms, including cyanobacteria. The iron-containing SOD (SodB) is one of the most abundant soluble proteins in the cytosol of the nitrogen-fixing cyanobacterium Nostoc punctiforme ATCC 29133, and therefore, we investigated its biochemical properties and response to oxidative stress. The putative SodB-encoding open reading frame Npun_R6491 was cloned and overexpressed in Escherichia coli as a C-terminally hexahistidine-tagged protein. The purified recombinant protein had a SodB specific activity of 2560 ± 48 U/mg protein at pH 7.8 and was highly thermostable. The presence of a characteristic iron absorption peak at 350 nm, and its sensitivity to H2O2 and azide, confirmed that the SodB is an iron-containing SOD. Transcript level of SodB in nitrogen-fixing cultures of N. punctiforme decreased considerably (threefold) after exposure to an oxidative stress-generating herbicide methyl viologen for 4 h. Furthermore, in-gel SOD activity analysis of such cultures grown at increasing concentrations of methyl viologen also showed a loss of SodB activity. These results suggest that SodB is not the primary scavenger of superoxide radicals induced by methyl viologen in N. punctiforme.

  18. Ammonium/methylammonium permeases of a Cyanobacterium. Identification and analysis of three nitrogen-regulated amt genes in synechocystis sp. PCC 6803.

    PubMed

    Montesinos, M L; Muro-Pastor, A M; Herrero, A; Flores, E

    1998-11-20

    Ammonium is an important nitrogen source for many microorganisms and plants. Ammonium transporters whose activity can be probed with [14C]methylammonium have been described in several organisms including some cyanobacteria, and amt genes encoding ammonium/methylammonium permeases have been recently identified in yeast, Arabidopsis thaliana, and some bacteria. The unicellular cyanobacterium Synechocystis sp. PCC 6803 exhibited a [14C]methylammonium uptake activity that was inhibited by externally added ammonium. Three putative amt genes that are found in the recently published complete sequence of the chromosome of strain PCC 6803 were inactivated by insertion of antibiotic resistance-encoding gene-cassettes. The corresponding mutant strains were impaired in uptake of [14C]methylammonium. Open reading frame sll0108 (amt1) was responsible for a high affinity uptake activity (Ks for methylammonium, 2.7 microM), whereas open reading frames sll1017 (amt2) and sll0537 (amt3) made minor contributions to uptake at low substrate concentrations. Expression of the three amt genes was higher in nitrogen-starved cells than in cells incubated in the presence of a source of nitrogen (either ammonium or nitrate), but amt1 was expressed at higher levels than the other two amt genes. Transcription of amt1 was found to take place from a promoter bearing the structure of the cyanobacterial promoters activated by the nitrogen control transcription factor, NtcA.

  19. Contribution of a Sodium Ion Gradient to Energy Conservation during Fermentation in the Cyanobacterium Arthrospira (Spirulina) maxima CS-328 ▿ †

    PubMed Central

    Carrieri, Damian; Ananyev, Gennady; Lenz, Oliver; Bryant, Donald A.; Dismukes, G. Charles

    2011-01-01

    Sodium gradients in cyanobacteria play an important role in energy storage under photoautotrophic conditions but have not been well studied during autofermentative metabolism under the dark, anoxic conditions widely used to produce precursors to fuels. Here we demonstrate significant stress-induced acceleration of autofermentation of photosynthetically generated carbohydrates (glycogen and sugars) to form excreted organic acids, alcohols, and hydrogen gas by the halophilic, alkalophilic cyanobacterium Arthrospira (Spirulina) maxima CS-328. When suspended in potassium versus sodium phosphate buffers at the start of autofermentation to remove the sodium ion gradient, photoautotrophically grown cells catabolized more intracellular carbohydrates while producing 67% higher yields of hydrogen, acetate, and ethanol (and significant amounts of lactate) as fermentative products. A comparable acceleration of fermentative carbohydrate catabolism occurred upon dissipating the sodium gradient via addition of the sodium-channel blocker quinidine or the sodium-ionophore monensin but not upon dissipating the proton gradient with the proton-ionophore dinitrophenol (DNP). The data demonstrate that intracellular energy is stored via a sodium gradient during autofermentative metabolism and that, when this gradient is blocked, the blockage is compensated by increased energy conversion via carbohydrate catabolism. PMID:21890670

  20. Impact of Different Group 2 Sigma Factors on Light Use Efficiency and High Salt Stress in the Cyanobacterium Synechocystis sp. PCC 6803

    PubMed Central

    Tyystjärvi, Taina; Huokko, Tuomas; Rantamäki, Susanne; Tyystjärvi, Esa

    2013-01-01

    Sigma factors of RNA polymerase recognize promoters and have a central role in controlling transcription initiation and acclimation to changing environmental conditions. The cyanobacterium Synechocystis sp. PCC 6803 encodes four non-essential group 2 sigma factors, SigB, SigC, SigD and SigE that closely resemble the essential SigA factor. Three out of four group 2 sigma factors were simultaneously inactivated and acclimation responses of the triple inactivation strains were studied. All triple inactivation strains grew slowly in low light, and our analysis suggests that the reason is a reduced capacity to adjust the perception of light. Simultaneous inactivation of SigB and SigD hampered growth also in high light. SigB is the most important group 2 sigma factor for salt acclimation, and elimination of all the other group 2 sigma factors slightly improved the salt tolerance of Synechocystis. Presence of only SigE allowed full salt acclimation including up-regulation of hspA and ggpS genes, but more slowly than SigB. Cells with only SigD acclimated to high salt but the acclimation processes differed from those of the control strain. Presence of only SigC prevented salt acclimation. PMID:23638176

  1. Overexpression of serine hydroxymethyltransferase from halotolerant cyanobacterium in Escherichia coli results in increased accumulation of choline precursors and enhanced salinity tolerance.

    PubMed

    Waditee-Sirisattha, Rungaroon; Sittipol, Daungjai; Tanaka, Yoshito; Takabe, Teruhiro

    2012-08-01

    Serine hydroxymethyltransferase (SHMT) is a key enzyme in cellular one-carbon pathway and has been studied in many living organisms from bacteria to higher plants and mammals. However, biochemical and molecular characterization of SHMT from photoautotrophic microorganisms remains a challenge. Here, we isolated the SHMT gene from a halotolerant cyanobacterium Aphanothece halophytica (ApSHMT) and expressed it in Escherichia coli. Purified recombinant ApSHMT protein exhibited catalytic reactions for dl-threo-3-phenylserine as well as for l-serine. Catalytic reaction for l-serine was strongly inhibited by NaCl, but not to that level with glycine betaine. Overexpression of ApSHMT in E. coli resulted in the increased accumulation of glycine and serine. Choline and glycine betaine levels were also significantly increased. Under high salinity, the growth rate of ApSHMT-expressing cells was faster compared to its respective control. High salinity also strongly induced the transcript level of ApSHMT in A. halophytica. Our results indicate the importance of a novel pathway; salt-induced ApSHMT increased the level of glycine betaine via serine and choline and conferred the tolerance to salinity stress.

  2. Economic Realities.

    ERIC Educational Resources Information Center

    Van Alstyne, Carol

    Concerns relating to the economics of higher education, including inflation, are considered. It is suggested that future sources of rising costs are energy, equipment, books, and federal requirements, and that another major economic concern involves trends in enrollments and in tuition revenues. Projections of declining enrollments should be…

  3. Economics 301.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education, Winnipeg.

    The purpose of this one-credit economics course for secondary schools in Manitoba (Canada) is to help students develop skills in business education and to provide them with basic information about how the Canadian economic system affects business, government, and the individual. The course requires 110 to 220 hours of instruction. Students study…

  4. Economics Pupils

    ERIC Educational Resources Information Center

    Scott, Alexander; Straker-Cook, Dawn

    1976-01-01

    This paper contains survey information relating to the relative performance of economics pupils at"A" level, their feelings about the subject, and the type of teaching to which they are exposed. The primary concern is to stimulate debate about the issues raised. Journal is available from: Economics Association, Room 340, Hamilton House, Mabledon…

  5. China: An Unlikely Economic Hegemon

    DTIC Science & Technology

    2014-01-01

    boom cannot remain in place once a certain level of power is reached. Based on this conflict, Samuel Huntington’s observation that “economic growth...have created an economic boom for China in recent years, its growing economic power will make it increasingly difficult to keep its currency value...final aspect to this lopsided picture, but perhaps one of the most important dynamics to the current economic boom , is massive state in- vestment in

  6. Intercellular transfer along the trichomes of the invasive terminal heterocyst forming cyanobacterium Cylindrospermopsis raciborskii CS-505.

    PubMed

    Plominsky, Álvaro M; Delherbe, Nathalie; Mandakovic, Dinka; Riquelme, Brenda; González, Karen; Bergman, Birgitta; Mariscal, Vicente; Vásquez, Mónica

    2015-03-01

    Cylindrospermopsis raciborskii CS-505 is an invasive freshwater filamentous cyanobacterium that when grown diazotrophically may develop trichomes of up to 100 vegetative cells while differentiating only two end heterocysts, the sole sites for their N2-fixation process. We examined the diazotrophic growth and intercellular transfer mechanisms in C. raciborskii CS-505. Subjecting cultures to a combined-nitrogen-free medium to elicit N2 fixation, the trichome length remained unaffected while growth rates decreased. The structures and proteins for intercellular communication showed that while a continuous periplasmic space was apparent along the trichomes, the putative septal junction sepJ gene is divided into two open reading frames and lacks several transmembrane domains unlike the situation in Anabaena, differentiating a 5-fold higher frequency of heterocysts. FRAP analyses also showed that the dyes calcein and 5-CFDA were taken up by heterocysts and vegetative cells, and that the transfer from heterocysts and 'terminal' vegetative cells showed considerably higher transfer rates than that from vegetative cells located in the middle of the trichomes. The data suggest that C. raciborskii CS-505 compensates its low-frequency heterocyst phenotype by a highly efficient transfer of the fixed nitrogen towards cells in distal parts of the trichomes (growing rapidly) while cells in central parts suffers (slow growth).

  7. Ultrafast primary processes in photosystem I of the cyanobacterium Synechocystis sp. PCC 6803.

    PubMed Central

    Savikhin, S; Xu, W; Soukoulis, V; Chitnis, P R; Struve, W S

    1999-01-01

    Ultrafast primary processes in the trimeric photosystem I core antenna-reaction center complex of the cyanobacterium Synechocystis sp. PCC 6803 have been examined in pump-probe experiments with approximately 100 fs resolution. A global analysis of two-color profiles, excited at 660 nm and probed at 5 nm intervals from 650 to 730 nm, reveals 430 fs kinetics for spectral equilibration among bulk antenna chlorophylls. At least two lifetime components (2.0 and 6.5 ps in our analysis) are required to describe equilibration of bulk chlorophylls with far red-absorbing chlorophylls (>700 nm). Trapping at P700 occurs with 24-ps kinetics. The multiphasic bulk left arrow over right arrow red equilibration kinetics are intriguing, because prior steady-state spectral studies have suggested that the core antenna in Synechocystis sp. contains only one red-absorbing chlorophyll species (C708). The disperse kinetics may arise from inhomogeneous broadening in C708. The one-color optical anisotropy at 680 nm (near the red edge of the bulk antenna) decays with 590 fs kinetics; the corresponding anisotropy at 710 nm shows approximately 3.1 ps kinetics. The latter may signal equilibration among symmetry-equivalent red chlorophylls, bound to different monomers within trimeric photosystem I. PMID:10354453

  8. Paired cloning vectors for complementation of mutations in the cyanobacterium Anabaena sp. strain PCC 7120

    SciTech Connect

    Wolk, C. Peter Wolk; Fan, Qing; Zhou, Ruanbao; Huang, Guocun; Lechno-Yossef, Sigal; Kuritz, Tanya; Wojciuch, Elizabeth

    2007-01-01

    The clones generated in a sequencing project represent a resource for subsequent analysis of the organism whose genome has been sequenced. We describe an interrelated group of cloning vectors that either integrate into the genome or replicate, and that enhance the utility, for developmental and other studies, of the clones used to determine the genomic sequence of the cyanobacterium, Anabaena sp. strain PCC 7120. One integrating vector is a mobilizable BAC vector that was used both to generate bridging clones and to complement transposon mutations. Upon addition of a cassette that permits mobilization and selection, pUC-based sequencing clones can also integrate into the genome and thereupon complement transposon mutations. The replicating vectors are based on cyanobacterial plasmid pDU1, whose sequence we report, and on broad-host-range plasmid RSF1010. The RSF1010- and pDU1-based vectors provide the opportunity to express different genes from either cell-type-specific or -generalist promoters, simultaneously from different plasmids in the same cyanobacterial cells. We show that pDU1 ORF4 and its upstream region play an essential role in the replication and copy number of pDU1, and that ORFs alr2887 and alr3546 (hetF{sub A}) of Anabaena sp. are required specifically for fixation of dinitrogen under oxic conditions.

  9. Anoxygenic photosynthesis controls oxygenic photosynthesis in a cyanobacterium from a sulfidic spring.

    PubMed

    Klatt, Judith M; Al-Najjar, Mohammad A A; Yilmaz, Pelin; Lavik, Gaute; de Beer, Dirk; Polerecky, Lubos

    2015-03-01

    Before the Earth's complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium, Pseudanabaena strain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism's affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However, Pseudanabaena FS39 additionally assimilated NO3 (-) during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life.

  10. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs.

    PubMed

    Klatt, Judith M; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    2015-09-01

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2 S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2 S: (i) H2 S accelerated the recovery of photosynthesis after prolonged exposure to darkness and anoxia. We suggest that this is possibly due to regulatory effects of H2 S on photosystem I components and/or on the Calvin cycle. (ii) H2 S concentrations of up to 210 μM temporarily enhanced the photosynthetic rates at low irradiance. Modelling showed that this enhancement is plausibly based on changes in the light-harvesting efficiency. (iii) Above a certain light-dependent concentration threshold H2 S also acted as an inhibitor. Intriguingly, this inhibition was not instant but occurred only after a specific time interval that decreased with increasing light intensity. That photosynthesis is most sensitive to inhibition at high light intensities suggests that H2 S inactivates an intermediate of the oxygen evolving complex that accumulates with increasing light intensity. We discuss the implications of these three effects of H2 S in the context of cyanobacterial photosynthesis under conditions with diurnally fluctuating light and H2 S concentrations, such as those occurring in microbial mats and biofilms.

  11. Isolation and characterization of a new reported cyanobacterium Leptolyngbya bijugata coproducing odorous geosmin and 2-methylisoborneol.

    PubMed

    Wang, Zhongjie; Xiao, Peng; Song, Gaofei; Li, Yeguang; Li, Renhui

    2015-08-01

    The earthy-musty compounds geosmin and 2-methylisoborneol (MIB) produced by cyanobacteria are considered as the main biological causes of off-flavor events, especially in aquatic ecosystems. More than 50 filamentous cyanobacteria species have been documented as geosmin or MIB producers; however, little is known about the species coproducing these two metabolites. In this study, an epiphytic sample was collected from a river in Hubei, China. Three isolated strains (A2, B2, and B4) producing earthy odors were successfully isolated and identified as the cyanobacterium Leptolyngbya bijugata Anagnostidis et Komárek 1988 based on morphology and 16S rDNA sequences. Gas chromatography analysis confirmed that the isolated L. bijugata strains were geosmin and MIB coproducers, with accumulation ranging from 13.6 to 22.4 and 12.3 to 57.5 μg L(-1), respectively. The partial fragments of geosmin and MIB synthesis genes in the L. bijugata strains were cloned and sequenced. Further sequences and phylogenetic analysis indicated the high conservation and a common origin of these genes in cyanobacteria. This study is the first to report and characterize the coproduction of geosmin and MIB by L. bijugata, representing a new source for potential risk of off-flavor events.

  12. Diazotrophic specific cytochrome c oxidase required to overcome light stress in the cyanobacterium Nostoc muscorum.

    PubMed

    Bhargava, Santosh; Chouhan, Shweta

    2016-01-01

    Diazotrophic, filamentous and heterocystous cyanobacterium Nostoc muscorum perform photosynthesis in vegetative whereas nitrogen fixation occurs in heterocyst only. However, despite their metabolic plasticity, respiration takes place both in vegetative cells and heterocysts. The role of the respiratory electron transport system and terminal oxidases under light stress is not evident so far. As compared to the diazotrophically grown cultures, the non-diazotrophically grown cultures of the N. muscorum show a slight decrease in their growth, chlorophyll a contents and photosynthetic O2 evolution under light stress. Whereas respiratory O2 uptake under identical stress condition increases several fold. Likewise, nitrogen fixing enzyme i.e. nitrogenase over-expresses itself under light stress condition. The terminal enzyme of respiratory electron transport chain i.e. cytochrome c oxidase shows more activity under light stress, whilst light stress has no impact on Ca(++)-dependent ATPase activity. This leads to the conclusion that under light stress, cytochrome c oxidase plays a vital role in mitigating given light stress.

  13. Structural Elucidation and Molecular Docking of a Novel Antibiotic Compound from Cyanobacterium Nostoc sp. MGL001.

    PubMed

    Niveshika; Verma, Ekta; Mishra, Arun K; Singh, Angad K; Singh, Vinay K

    2016-01-01

    Cyanobacteria are rich source of array of bioactive compounds. The present study reports a novel antibacterial bioactive compound purified from cyanobacterium Nostoc sp. MGL001 using various chromatographic techniques viz. thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Further characterization was done using electrospray ionization mass spectroscopy (ESIMS) and nuclear magnetic resonance (NMR) and predicted structure of bioactive compound was 9-Ethyliminomethyl-12-(morpholin - 4 - ylmethoxy) -5, 8, 13, 16-tetraaza-hexacene - 2, 3 dicarboxylic acid (EMTAHDCA). Structure of EMTAHDCA clearly indicated that it is a novel compound that was not reported in literature or natural product database. The compound exhibited growth inhibiting effects mainly against the gram negative bacterial strains and produced maximum zone of inhibition at 150 μg/mL concentration. The compound was evaluated through in silico studies for its ability to bind 30S ribosomal fragment (PDB ID: 1YRJ, 1MWL, 1J7T, and 1LC4) and OmpF porin protein (4GCP, 4GCQ, and 4GCS) which are the common targets of various antibiotic drugs. Comparative molecular docking study revealed that EMTAHDCA has strong binding affinity for these selected targets in comparison to a number of most commonly used antibiotics. The ability of EMTAHDCA to bind the active sites on the proteins and 30S ribosomal fragments where the antibiotic drugs generally bind indicated that it is functionally similar to the commercially available drugs.

  14. Excitation energy transfer in phycobiliproteins of the cyanobacterium Acaryochloris marina investigated by spectral hole burning.

    PubMed

    Pieper, Jörg; Rätsep, Margus; Golub, Maksym; Schmitt, Franz-Josef; Artene, Petrica; Eckert, Hann-Jörg

    2017-09-01

    The cyanobacterium Acaryochloris marina developed two types of antenna complexes, which contain chlorophyll-d (Chl d) and phycocyanobilin (PCB) as light-harvesting pigment molecules, respectively. The latter membrane-extrinsic complexes are denoted as phycobiliproteins (PBPs). Spectral hole burning was employed to study excitation energy transfer and electron-phonon coupling in PBPs. The data reveal a rich spectral substructure with a total of four low-energy electronic states whose absorption bands peak at 633, 644, 654, and at about 673 nm. The electronic states at ~633 and 644 nm can be tentatively attributed to phycocyanin (PC) and allophycocyanin (APC), respectively. The remaining low-energy electronic states including the terminal emitter at 673 nm may be associated with different isoforms of PC, APC, or the linker protein. Furthermore, the hole burning data reveal a large number of excited state vibrational frequencies, which are characteristic for the chromophore PCB. In summary, the results are in good agreement with the low-energy level structure of PBPs and electron-phonon coupling parameters reported by Gryliuk et al. (BBA 1837:1490-1499, 2014) based on difference fluorescence line-narrowing experiments.

  15. Proteome-Wide Analysis and Diel Proteomic Profiling of the Cyanobacterium Arthrospira platensis PCC 8005

    PubMed Central

    Matallana-Surget, Sabine; Derock, Jérémy; Leroy, Baptiste; Badri, Hanène; Deschoenmaeker, Frédéric; Wattiez, Ruddy

    2014-01-01

    The filamentous cyanobacterium Arthrospira platensis has a long history of use as a food supply and it has been used by the European Space Agency in the MELiSSA project, an artificial microecosystem which supports life during long-term manned space missions. This study assesses progress in the field of cyanobacterial shotgun proteomics and light/dark diurnal cycles by focusing on Arthrospira platensis. Several fractionation workflows including gel-free and gel-based protein/peptide fractionation procedures were used and combined with LC-MS/MS analysis, enabling the overall identification of 1306 proteins, which represents 21% coverage of the theoretical proteome. A total of 30 proteins were found to be significantly differentially regulated under light/dark growth transition. Interestingly, most of the proteins showing differential abundance were related to photosynthesis, the Calvin cycle and translation processes. A novel aspect and major achievement of this work is the successful improvement of the cyanobacterial proteome coverage using a 3D LC-MS/MS approach, based on an immobilized metal affinity chromatography, a suitable tool that enabled us to eliminate the most abundant protein, the allophycocyanin. We also demonstrated that cell growth follows a light/dark cycle in A. platensis. This preliminary proteomic study has highlighted new characteristics of the Arthrospira platensis proteome in terms of diurnal regulation. PMID:24914774

  16. Crystal Structure of Allophycocyanin from Marine Cyanobacterium Phormidium sp. A09DM

    PubMed Central

    Gupta, Gagan Deep; Madamwar, Datta

    2015-01-01

    Isolated phycobilisome (PBS) sub-assemblies have been widely subjected to X-ray crystallography analysis to obtain greater insights into the structure-function relationship of this light harvesting complex. Allophycocyanin (APC) is the phycobiliprotein always found in the PBS core complex. Phycocyanobilin (PCB) chromophores, covalently bound to conserved Cys residues of α- and β- subunits of APC, are responsible for solar energy absorption from phycocyanin and for transfer to photosynthetic apparatus. In the known APC structures, heterodimers of α- and β- subunits (known as αβ monomers) assemble as trimer or hexamer. We here for the first time report the crystal structure of APC isolated from a marine cyanobacterium (Phormidium sp. A09DM). The crystal structure has been refined against all the observed data to the resolution of 2.51 Å to Rwork (Rfree) of 0.158 (0.229) with good stereochemistry of the atomic model. The Phormidium protein exists as a trimer of αβ monomers in solution and in crystal lattice. The overall tertiary structures of α- and β- subunits, and trimeric quaternary fold of the Phormidium protein resemble the other known APC structures. Also, configuration and conformation of the two covalently bound PCB chromophores in the marine APC are same as those observed in fresh water cyanobacteria and marine red algae. More hydrophobic residues, however, constitute the environment of the chromophore bound to α-subunit of the Phormidium protein, owing mainly to amino acid substitutions in the marine protein. PMID:25923120

  17. Silanimonas algicola sp. nov., isolated from laboratory culture of a bloom-forming cyanobacterium, Microcystis.

    PubMed

    Chun, Seong-Jun; Cui, Yingshun; Ko, So-Ra; Lee, Hyung-Gwan; Oh, Hee-Mock; Ahn, Chi-Yong

    2017-09-01

    A Gram-stain-negative, aerobic, rod-shaped and motile bacterium, designated M23T, was isolated from a laboratory culture of a bloom-forming cyanobacterium, Microcystis, which was isolated from a eutrophic lake in Korea. The strain grew optimally without NaCl and at 25-30 °C on R2A agar medium. Phylogenetic analysis based on 16S rRNA gene sequences positioned the novel strain among the genus Silanimonas, with the highest similarity to Silanimonas lenta DSM 16282T (98.5 %). DNA-DNA relatedness between strain M23T and the closely related species in the genus Silanimonas was <30 %. Strain M23T contained iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and iso-C16 : 0 as major fatty acids and ubiquinone-8 (Q-8) as the major quinone. Strain M23T contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylmethylethanolamine as major polar lipids. The DNA G+C content of strain M23T was 69.6 mol%. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain M23T represents a novel species in the genus Silanimonas, for which the name Silanimonas algicola sp. nov. is proposed. The type strain is M23T (=KCTC 52219T=JCM 31889T).

  18. A biliverdin-binding cyanobacteriochrome from the chlorophyll d–bearing cyanobacterium Acaryochloris marina

    PubMed Central

    Narikawa, Rei; Nakajima, Takahiro; Aono, Yuki; Fushimi, Keiji; Enomoto, Gen; Ni-Ni-Win; Itoh, Shigeru; Sato, Moritoshi; Ikeuchi, Masahiko

    2015-01-01

    Cyanobacteriochromes (CBCRs) are linear tetrapyrrole-binding photoreceptors in cyanobacteria that absorb visible and near-ultraviolet light. CBCRs are divided into two types based on the type of chromophore they contain: phycocyanobilin (PCB) or phycoviolobilin (PVB). PCB-binding CBCRs reversibly photoconvert at relatively long wavelengths, i.e., the blue-to-red region, whereas PVB-binding CBCRs reversibly photoconvert at shorter wavelengths, i.e., the near-ultraviolet to green region. Notably, prior to this report, CBCRs containing biliverdin (BV), which absorbs at longer wavelengths than do PCB and PVB, have not been found. Herein, we report that the typical red/green CBCR AM1_1557 from the chlorophyll d–bearing cyanobacterium Acaryochloris marina can bind BV almost comparable to PCB. This BV-bound holoprotein reversibly photoconverts between a far red light–absorbing form (Pfr, λmax = 697 nm) and an orange light–absorbing form (Po, λmax = 622 nm). At room temperature, Pfr fluoresces with a maximum at 730 nm. These spectral features are red-shifted by 48~77 nm compared with those of the PCB-bound domain. Because the absorbance of chlorophyll d is red-shifted compared with that of chlorophyll a, the BV-bound AM1_1557 may be a physiologically relevant feature of A. marina and is potentially useful as an optogenetic switch and/or fluorescence imager. PMID:25609645

  19. Sequential splicing of a group II twintron in the marine cyanobacterium Trichodesmium

    PubMed Central

    Pfreundt, Ulrike; Hess, Wolfgang R.

    2015-01-01

    The marine cyanobacterium Trichodesmium is unusual in its genomic architecture as 40% of the genome is occupied by non-coding DNA. Although the majority of it is transcribed into RNA, it is not well understood why such a large non-coding genome fraction is maintained. Mobile genetic elements can contribute to genome expansion. Many bacteria harbor introns whereas twintrons, introns-in-introns, are rare and not known to interrupt protein-coding genes in bacteria. Here we show the sequential in vivo splicing of a 5400 nt long group II twintron interrupting a highly conserved gene that is associated with RNase HI in some cyanobacteria, but free-standing in others, including Trichodesmium erythraeum. We show that twintron splicing results in a putatively functional mRNA. The full genetic arrangement was found conserved in two geospatially distinct metagenomic datasets supporting its functional relevance. We further show that splicing of the inner intron yields the free intron as a true circle. This reaction requires the spliced exon reopening (SER) reaction to provide a free 5′ exon. The fact that Trichodesmium harbors a functional twintron fits in well with the high intron load of these genomes, and suggests peculiarities in its genetic machinery permitting such arrangements. PMID:26577185

  20. Changes in photosynthesis and pigmentation in an agp deletion mutant of the cyanobacterium Synechocystis sp.

    PubMed

    Miao, Xiaoling; Wu, Qingyu; Wu, Guifang; Zhao, Nanming

    2003-03-01

    The agp gene encoding ADP-glucose pyrophosphorylase is involved in cyanobacterial glycogen synthesis. By in vitro DNA recombination technology, agp deletion mutant (agp-) of cyanobacterium Synechocystis sp. PCC 6803 was constructed. This mutation led to a complete absence of glycogen biosynthesis. As compared with WT (wild type), a 60% decrease in ratio of the c-phycocyanine/chlorophyll a and no significant change in the carotenoid/chlorophyll a were observed in agp- cells. The agp- mutant had 38% less photosynthetic capacity when grown in light over 600 micromol m(-2) s(-1). Under lower light intensity, the final biomass of the mutant strain was only 1.1 times of that of the WT strain under mixotrophic condition after 6 d culture. Under higher light intensity, however, the final biomass of the WT strain under mixotrophic conditions was 3 times that of the mutant strain after 6 d culture and 1.5 times under photoautotrophic conditions. The results indicate that there is a minimum requirement for glycogen synthesis for normal growth and development in cyanobacteria.

  1. Structural Elucidation and Molecular Docking of a Novel Antibiotic Compound from Cyanobacterium Nostoc sp. MGL001

    PubMed Central

    Niveshika; Verma, Ekta; Mishra, Arun K.; Singh, Angad K.; Singh, Vinay K.

    2016-01-01

    Cyanobacteria are rich source of array of bioactive compounds. The present study reports a novel antibacterial bioactive compound purified from cyanobacterium Nostoc sp. MGL001 using various chromatographic techniques viz. thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Further characterization was done using electrospray ionization mass spectroscopy (ESIMS) and nuclear magnetic resonance (NMR) and predicted structure of bioactive compound was 9-Ethyliminomethyl-12-(morpholin - 4 - ylmethoxy) -5, 8, 13, 16–tetraaza–hexacene - 2, 3 dicarboxylic acid (EMTAHDCA). Structure of EMTAHDCA clearly indicated that it is a novel compound that was not reported in literature or natural product database. The compound exhibited growth inhibiting effects mainly against the gram negative bacterial strains and produced maximum zone of inhibition at 150 μg/mL concentration. The compound was evaluated through in silico studies for its ability to bind 30S ribosomal fragment (PDB ID: 1YRJ, 1MWL, 1J7T, and 1LC4) and OmpF porin protein (4GCP, 4GCQ, and 4GCS) which are the common targets of various antibiotic drugs. Comparative molecular docking study revealed that EMTAHDCA has strong binding affinity for these selected targets in comparison to a number of most commonly used antibiotics. The ability of EMTAHDCA to bind the active sites on the proteins and 30S ribosomal fragments where the antibiotic drugs generally bind indicated that it is functionally similar to the commercially available drugs. PMID:27965634

  2. The dynamic behavior of phycobilisome movement during light state transitions in cyanobacterium Synechocystis PCC6803.

    PubMed

    Yang, Shuzhen; Zhang, Rui; Hu, Changchao; Xie, Jie; Zhao, Jingquan

    2009-02-01

    Light state transition is a physiological function of oxygenic organisms to balance the excitation of photosystem II (PSII) and photosystem I (PSI), hence a prerequisite of oxygen-evolving photosynthesis. For cyanobacteria, phycobilisome (PBS) movement during light state transition has long been expected, but never observed. Here the dynamic behavior of PBS movement during state transition in cyanobacterium Synechocystis PCC6803 is experimentally detected via time-dependent fluorescence fluctuation. Under continuous excitation of PBSs in the intact cells, time-dependent fluorescence fluctuations resemble "damped oscillation" mode, which indicates dynamic searching of a PBS in an "overcorrection" manner for the "balance" position where PSII and PSI are excited equally. Based on the parallel model, it is suggested that the "damped oscillation" fluorescence fluctuation is originated from a collective movement of all the PBSs to find the "balance" position. Based on the continuous fluorescence fluctuation during light state transition and also variety of solar spectra, it may be deduced that light state transition of oxygen-evolution organisms is a natural behavior that occurs daily rather than an artificial phenomenon at extreme light conditions in laboratory.

  3. Proteome-wide analysis and diel proteomic profiling of the cyanobacterium Arthrospira platensis PCC 8005.

    PubMed

    Matallana-Surget, Sabine; Derock, Jérémy; Leroy, Baptiste; Badri, Hanène; Deschoenmaeker, Frédéric; Wattiez, Ruddy

    2014-01-01

    The filamentous cyanobacterium Arthrospira platensis has a long history of use as a food supply and it has been used by the European Space Agency in the MELiSSA project, an artificial microecosystem which supports life during long-term manned space missions. This study assesses progress in the field of cyanobacterial shotgun proteomics and light/dark diurnal cycles by focusing on Arthrospira platensis. Several fractionation workflows including gel-free and gel-based protein/peptide fractionation procedures were used and combined with LC-MS/MS analysis, enabling the overall identification of 1306 proteins, which represents 21% coverage of the theoretical proteome. A total of 30 proteins were found to be significantly differentially regulated under light/dark growth transition. Interestingly, most of the proteins showing differential abundance were related to photosynthesis, the Calvin cycle and translation processes. A novel aspect and major achievement of this work is the successful improvement of the cyanobacterial proteome coverage using a 3D LC-MS/MS approach, based on an immobilized metal affinity chromatography, a suitable tool that enabled us to eliminate the most abundant protein, the allophycocyanin. We also demonstrated that cell growth follows a light/dark cycle in A. platensis. This preliminary proteomic study has highlighted new characteristics of the Arthrospira platensis proteome in terms of diurnal regulation.

  4. Anaerobic biosynthesis of unsaturated fatty acids in the cyanobacterium, Oscillatoria limnetica

    NASA Technical Reports Server (NTRS)

    Jahnke, L. L.; Lee, B.; Sweeney, M. J.; Klein, H. P.

    1989-01-01

    The mechanism for synthesis of monounsaturated fatty acids under aerobic and anaerobic conditions was studied in the facultative anaerobic cyanobacterium, Oscillatoria limnetica. The hexadecenoic acid (C16:1) of aerobically grown O. limnetica was shown to contain both the delta 7 (79%) and delta 9 (21%) isomers, while the octadecenoic (C18:1) acid was entirely the delta 9 acid. Incorporation of [2-14C] acetate into the fatty acids under aerobic conditions resulted in synthesis of the delta 7 and delta 9 C16:1 and the delta 9 C18:1. Synthesis of unsaturated fatty acids in the presence of DCMU required sulfide. Anaerobic incubations in the presence of DCMU and sulfide (less than 0.003% atmospheric oxygen) resulted in a two-fold increase in monounsaturated fatty acids of both delta 7 and delta 9 C16:1 and delta 9 and delta 11 C18:1. The synthesis of these is characteristic of a bacterial-type, anaerobic pathway.

  5. Nitrate transport in the cyanobacterium Anacystis nidulans R2. Kinetic and energetic aspects.

    PubMed Central

    Rodríguez, R; Lara, C; Guerrero, M G

    1992-01-01

    Nitrate transport has been studied in the cyanobacterium Anacystis nidulans R2 by monitoring intracellular nitrate accumulation in intact cells of the mutant strain FM6, which lacks nitrate reductase activity and is therefore unable to reduce the transported nitrate. Kinetic analysis of nitrate transport as a function of external nitrate concentration revealed apparent substrate inhibition, with a peak velocity at 20-25 microM-nitrate. A Ks (NO3-) of 1 microM was calculated. Nitrate transport exhibited a stringent requirement for Na+. Neither Li+ nor K+ could substitute for Na+. Monensin depressed nitrate transport in a concentration-dependent manner, inhibition being more than 60% at 2 microM, indicating that the Na(+)-dependence of active nitrate transport relies on the maintenance of a Na+ electrochemical gradient. The operation of an Na+/NO3- symport system is suggested. Nitrite behaved as an effective competitive inhibitor of nitrate transport, with a Ki (NO2-) of 3 microM. The time course of nitrite inhibition of nitrate transport was consistent with competitive inhibition by mixed alternative substrates. Nitrate and nitrite might be transported by the same carrier. PMID:1554347

  6. Growth inhibition of bloom-forming cyanobacterium Microcystis aeruginosa by rice straw extract.

    PubMed

    Park, M-H; Han, M-S; Ahn, C-Y; Kim, H-S; Yoon, B-D; Oh, H-M

    2006-09-01

    To inhibit the growth of the bloom-forming cyanobacterium Microcystis aeruginosa using a rice straw extract. The cell numbers of the algal strain M. aeruginosa UTEX 2388 significantly decreased after treatment with different concentrations (0.01, 0.1, 1 and 10 mg l(-1)) of a rice straw extract for an 8-day cultivation period. Among seven tested allelochemicals from rice straw, salicylic acid at 0.1 mg l(1) exhibited the highest allelopathic activity (26%) on day 8. A synergistic effect on algal growth inhibition was found when adding two or three phenolic compounds from the rice straw. The growth of M. aeruginosa was inhibited by rice straw extract concentrations ranging from 0.01 to 10 mg l(1). This activity was due to the synergistic effects of various phenolic compounds in the rice straw. The identification of rice straw as an effective material for the growth inhibition of M. aeruginosa implies it may have the potential to be used as an environment-friendly biomaterial for controlling the algal bloom of M. aeruginosa in eutrophic water.

  7. Molecular weight determination of an active photosystem I preparation from a thermophilic cyanobacterium, Synechococcus elongatus

    SciTech Connect

    Schafheutle, M.E.; Setlikova, E.; Timmins, P.A.; Johner, H.; Gutgesell, P.; Setlik, I.; Welte, W. )

    1990-02-06

    An active photosystem I (PSI) complex was isolated from the thermophilic cyanobacterium Synechococcus elongatus by a procedure consisting of three steps: First, extraction of photosystem II from the thylakoids by a sulfobetaine detergent yields PSI-enriched membranes. Second, the latter are treated with Triton X-100 to extract PSI particles, which are further purified by preparative isoelectric focusing. Third, anion-exchange chromatography is used to remove contaminating phycobilisome polypeptides. The purified particles show three major bands in sodium dodecyl sulfate gel electrophoresis of apparent molecular mass of 110, 15, and 10 kDa. Charge separation was monitored by the kinetics of flash-induced absorption changes at 820 nm. A chlorophyll/P700 ratio of 60 was found. When the particles are stored at 4 degrees C, charge separation was stable for weeks. The molecular mass of the PSI particles, determined by measurement of zero-angle neutron scattering intensity, was 217,000 Da. The PSI particles thus consist of one heterodimer of the 60-80-kDa polypeptides and presumably one copy of the 15- and 10-kDa polypeptides, respectively.

  8. Type II Toxin–Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803

    PubMed Central

    Kopfmann, Stefan; Roesch, Stefanie K.; Hess, Wolfgang R.

    2016-01-01

    Bacterial toxin–antitoxin (TA) systems are genetic elements, which are encoded by plasmid as well as chromosomal loci. They mediate plasmid and genomic island maintenance through post-segregational killing mechanisms but may also have milder effects, acting as mobile stress response systems that help certain cells of a population in persisting adverse growth conditions. Very few cyanobacterial TA system have been characterized thus far. In this work, we focus on the cyanobacterium Synechocystis 6803, a widely used model organism. We expand the number of putative Type II TA systems from 36 to 69 plus seven stand-alone components. Forty-seven TA pairs are located on the chromosome and 22 are plasmid-located. Different types of toxins are associated with various antitoxins in a mix and match principle. According to protein domains and experimental data, 81% of all toxins in Synechocystis 6803 likely exhibit RNase activity, suggesting extensive potential for toxicity-related RNA degradation and toxin-mediated transcriptome remodeling. Of particular interest is the Ssr8013–Slr8014 system encoded on plasmid pSYSG, which is part of a larger defense island or the pSYSX system Slr6056–Slr6057, which is linked to a bacterial ubiquitin-like system. Consequently, Synechocystis 6803 is one of the most prolific sources of new information about these genetic elements. PMID:27455323

  9. The hierarchy of transition metal homeostasis: iron controls manganese accumulation in a unicellular cyanobacterium.

    PubMed

    Sharon, Shir; Salomon, Eitan; Kranzler, Chana; Lis, Hagar; Lehmann, Robert; Georg, Jens; Zer, Hagit; Hess, Wolfgang R; Keren, Nir

    2014-12-01

    Iron and manganese are part of a small group of transition metals required for photosynthetic electron transport. Here, we present evidence for a functional link between iron and manganese homeostasis. In the unicellular cyanobacterium, Synechocystis sp. PCC 6803, Fe and Mn deprivation resulted in distinct modifications of the physiological status. The effect on growth and photosynthetic activity under Fe limitation were more severe than those observed under Mn limitation. Moreover, the intracellular elemental quotas of Fe and Mn were found to be linked. Fe limitation reduced the intracellular Mn quota. Mn limitation did not exert a reciprocal effect on Fe quotas. Microarray analysis comparing Mn and Fe limitation revealed a stark difference in the extent of the transcriptional response to the two limiting conditions, reflective of the physiological responses. The effects of Fe limitation on the transcriptional network are widespread while the effects on Mn limitation are highly specific. Our analysis also revealed an overlap in the transcriptional response of specific Fe and Mn transporters. This overlap provides a framework for explaining Fe limitation induced changes in Mn quotas.

  10. Composition of the carbohydrate granules of the cyanobacterium, Cyanothece sp. strain ATCC 51142

    NASA Technical Reports Server (NTRS)

    Schneegurt, M. A.; Sherman, D. M.; Sherman, L. A.; Mitchell, C. A. (Principal Investigator)

    1997-01-01

    Cyanothece sp. strain ATCC 51142 is an aerobic, unicellular, diazotrophic cyanobacterium that temporally separates O2-sensitive N2 fixation from oxygenic photosynthesis. The energy and reducing power needed for N2 fixation appears to be generated by an active respiratory apparatus that utilizes the contents of large interthylakoidal carbohydrate granules. We report here on the carbohydrate and protein composition of the granules of Cyanothece sp. strain ATCC 51142. The carbohydrate component is a glucose homopolymer with branches every nine residues and is chemically identical to glycogen. Granule-associated protein fractions showed temporal changes in the number of proteins and their abundance during the metabolic oscillations observed under diazotrophic conditions. There also were temporal changes in the protein pattern of the granule-depleted supernatant fractions from diazotrophic cultures. None of the granule-associated proteins crossreacted with antisera directed against several glycogen-metabolizing enzymes or nitrogenase, although these proteins were tentatively identified in supernatant fractions. It is suggested that the granule-associated proteins are structural proteins required to maintain a complex granule architecture.

  11. Toxin Release of Cyanobacterium Microcystis aeruginosa after Exposure to Typical Tetracycline Antibiotic Contaminants

    PubMed Central

    Ye, Jing; Du, Yuping; Wang, Lumei; Qian, Jingru; Chen, Jiejing; Wu, Qingwen; Hu, Xiaojun

    2017-01-01

    The global usage of veterinary antibiotics is significant. Antibiotics can be released into aquatic environments and elicit toxic effects on non-target organisms. In this study, the growth characteristics and toxin release of the cyanobacterium Microcystis aeruginosa (M. aeruginosa) were examined to investigate the physiological effects of tetracycline antibiotics on aquatic life. Results showed that the degree of toxicities of the following target antibiotics was TC (tetracycline hydrochloride) > CTC (chlortetracycline hydrochloride) > OTC (oxytetracycline hydrochloride) in terms of growth parameters, EC10 (0.63, 1.86, and 3.02 mg/L, respectively), and EC20 (1.58, 4.09, and 4.86 mg/L, respectively) values. These antibiotics inhibited the production of microcystin-LR (MC-LR) to varying degrees. CTC interfered M. aeruginosa cells and decreased their ability to release MC-LR, but this antibiotic stimulated the ability of these cells to synthesize MC-LR at 2 and 5 mg/L. OTC elicited a relatively weaker toxicity than CTC did and reduced MC-LR release. TC was the most toxic among the three antibiotics, and this antibiotic simultaneously reduced intracellular and extracellular MC-LR equivalents. Our results helped elucidate the effects of tetracycline antibiotics on M. aeruginosa, which is essential for environmental evaluation and protection. Our results are also helpful for guiding the application of veterinary antibiotics in agricultural settings. PMID:28230795

  12. Photosynthetic performance of a helical tubular photobioreactor incorporating the cyanobacterium Spirulina platensis

    SciTech Connect

    Watanabe, Yoshitomo; Hall, D.O.; Nouee, J. De La

    1995-07-20

    The photosynthetic performance of a helical tubular photobioreactor (``Biocoil``), incorporating the filamentous cyanobacterium Spirulina platensis, was investigated. The photobioreactor was constructed in a cylindrical shape with a 0.25-m{sup 2} basal area and a photostage comprising 60 m of transparent PVC tubing of 1.6-cm inner diameter. The inner surface of the cylinder was illuminated with cool white fluorescent lamps; the energy input of photosynthetically active radiation into the photobioreactor was 2,920 kJ per day. An air-lift system incorporating 4% CO{sub 2} was used to circulate the growth medium in the tubing. The maximum productivity achieved in batch culture was 7.18 g dry biomass per day which corresponded to a photosynthetic (PAR) efficiency of 5.45%. The CO{sub 2} was efficiently removed from the gaseous stream; monitoring the CO{sub 2} in the outlet and inlet gas streams showed a 70% removal of CO{sub 2} from the inlet gas over an 8-h period with almost maximum growth rate.

  13. An integrative approach to energy, carbon, and redox metabolism in the cyanobacterium Synechocystis sp. PCC 6803

    SciTech Connect

    Vermaas, Willem F.J.

    2006-03-14

    The broader goal of this project was to merge knowledge from genomic, metabolic, ultrastructural and other perspectives to understand how cyanobacteria live, adapt and are regulated. This understanding aids in metabolic engineering and synthetic biology efforts using this group of organisms that contribute greatly to global photosynthetic CO2 fixation and that are closely related to the ancestors of chloroplasts. This project focused on photosynthesis and respiration in the cyanobacterium Synechocystis sp. PCC 6803, which is spontaneously transformable and has a known genome sequence. Modification of these fundamental processes in this organism can lead to improved carbon sequestration and hydrogen production, as well as to generation of high-quality biomass. In our GTL-supported studies at Arizona State University we focus on cell structure and cell physiology in Synechocystis, with particular emphasis on thylakoid membrane formation and on metabolism related to photosynthesis and respiration. Results on (a) thylakoid membrane biogenesis, (b) fluxes through central carbon utilization pathways, and (c) distribution mechanisms between carbon storage compounds are presented. Together, these results help pave the way for metabolic engineering efforts that are likely to result in improved solar-powered carbon sequestration and bioenergy conversion. Fueled by the very encouraging results obtained in this project, we already have attracted interest from major companies in the use of cyanobacteria for biofuel production.

  14. Functional Diversity of Transcriptional Regulators in the Cyanobacterium Synechocystis sp. PCC 6803

    PubMed Central

    Shi, Mengliang; Zhang, Xiaoqing; Pei, Guangsheng; Chen, Lei; Zhang, Weiwen

    2017-01-01

    Functions of transcriptional regulators (TRs) are still poorly understood in the model cyanobacterium Synechocystis sp. PCC 6803. To address the issue, we constructed knockout mutants for 32 putative TR-encoding genes of Synechocystis, and comparatively analyzed their phenotypes under autotrophic growth condition and metabolic profiles using liquid chromatography-mass spectrometry-based metabolomics. The results showed that only four mutants of TR genes, sll1872 (lytR), slr0741 (phoU), slr0395 (ntcB), and slr1871 (pirR), showed differential growth patterns in BG11 medium when compared with the wild type; however, in spite of no growth difference observed for the remaining TR mutants, metabolomic profiling showed that they were different at the metabolite level, suggesting significant functional diversity of TRs in Synechocystis. In addition, an integrative metabolomic and gene families’ analysis of all TR mutants led to the identification of five pairs of TR genes that each shared close relationship in both gene families and metabolomic clustering trees, suggesting possible conserved functions of these TRs during evolution. Moreover, more than a dozen pairs of TR genes with different origin and evolution were found with similar metabolomic profiles, suggesting a possible functional convergence of the TRs during genome evolution. Finally, a protein–protein network analysis was performed to predict regulatory targets of TRs, allowing inference of possible regulatory gene targets for 4 out of five pairs of TRs. This study provided new insights into the regulatory functions and evolution of TR genes in Synechocystis. PMID:28270809

  15. Multiple modes of iron uptake by the filamentous, siderophore-producing cyanobacterium, Anabaena sp. PCC 7120.

    PubMed

    Rudolf, Mareike; Kranzler, Chana; Lis, Hagar; Margulis, Ketty; Stevanovic, Mara; Keren, Nir; Schleiff, Enrico

    2015-08-01

    Iron is a member of a small group of nutrients that limits aquatic primary production. Mechanisms for utilizing iron have to be efficient and adapted according to the ecological niche. In respect to iron acquisition cyanobacteria, prokaryotic oxygen evolving photosynthetic organisms can be divided into siderophore- and non-siderophore-producing strains. The results presented in this paper suggest that the situation is far more complex. To understand the bioavailability of different iron substrates and the advantages of various uptake strategies, we examined iron uptake mechanisms in the siderophore-producing cyanobacterium Anabaena sp. PCC 7120. Comparison of the uptake of iron complexed with exogenous (desferrioxamine B, DFB) or to self-secreted (schizokinen) siderophores by Anabaena sp. revealed that uptake of the endogenous produced siderophore complexed to iron is more efficient. In addition, Anabaena sp. is able to take up dissolved, ferric iron hydroxide species (Fe') via a reductive mechanism. Thus, Anabaena sp. exhibits both, siderophore- and non-siderophore-mediated iron uptake. While assimilation of Fe' and FeDFB are not induced by iron starvation, FeSchizokinen uptake rates increase with increasing iron starvation. Consequently, we suggest that Fe' reduction and uptake is advantageous for low-density cultures, while at higher densities siderophore uptake is preferred.

  16. Palmyramide A, a Cyclic Depsipeptide from a Palmyra Atoll Collection of the Marine Cyanobacterium Lyngbya majuscula

    PubMed Central

    Taniguchi, Masatoshi; Nunnery, Joshawna K.; Engene, Niclas; Esquenazi, Eduardo; Byrum, Tara; Dorrestein, Pieter C.; Gerwick, William H.

    2010-01-01

    Bioassay-guided fractionation of the extract of a consortium of a marine cyanobacterium and a red alga (Rhodophyta) led to the discovery of a novel compound, palmyramide A, along with the known compounds curacin D and malyngamide C. The planar structure of palmyramide A was determined by one- and two-dimensional NMR studies and mass spectrometry. Palmyramide A is a cyclic depsipeptide which features an unusual arrangement of three amino acids and three hydroxy acids; one of the hydroxy acids is the rare 2,2-dimethyl-3-hydroxyhexanoic acid unit (Dmhha). The absolute configurations of the six residues were determined by Marfey’s analysis, chiral HPLC analysis and GC/MS analysis of the hydrolysate. Morphological and phylogenetic studies revealed the sample to be composed of a Lyngbya majuscula-Centroceras sp. association. MALDI-imaging analysis of the cultured L. majuscula indicated that it was the true producer of this new depsipeptide. Pure palmyramide A showed sodium channel blocking activity in neuro-2a cells and cytotoxic activity in H-460 human lung carcinoma cells. PMID:19839606

  17. A review of the global ecology, genomics, and biogeography of the toxic cyanobacterium, Microcystis spp.

    PubMed

    Harke, Matthew J; Steffen, Morgan M; Gobler, Christopher J; Otten, Timothy G; Wilhelm, Steven W; Wood, Susanna A; Paerl, Hans W

    2016-04-01

    This review summarizes the present state of knowledge regarding the toxic, bloom-forming cyanobacterium, Microcystis, with a specific focus on its geographic distribution, toxins, genomics, phylogeny, and ecology. A global analysis found documentation suggesting geographic expansion of Microcystis, with recorded blooms in at least 108 countries, 79 of which have also reported the hepatatoxin microcystin. The production of microcystins (originally "Fast-Death Factor") by Microcystis and factors that control synthesis of this toxin are reviewed, as well as the putative ecophysiological roles of this metabolite. Molecular biological analyses have provided significant insight into the ecology and physiology of Microcystis, as well as revealed the highly dynamic, and potentially unstable, nature of its genome. A genetic sequence analysis of 27 Microcystis species, including 15 complete/draft genomes are presented. Using the strictest biological definition of what constitutes a bacterial species, these analyses indicate that all Microcystis species warrant placement into the same species complex since the average nucleotide identity values were above 95%, 16S rRNA nucleotide identity scores exceeded 99%, and DNA-DNA hybridization was consistently greater than 70%. The review further provides evidence from around the globe for the key role that both nitrogen and phosphorus play in controlling Microcystis bloom dynamics, and the effect of elevated temperature on bloom intensification. Finally, highlighted is the ability of Microcystis assemblages to minimize their mortality losses by resisting grazing by zooplankton and bivalves, as well as viral lysis, and discuss factors facilitating assemblage resilience.

  18. Growth enhancing effect of exogenous glycine and characterization of its uptake in halotolerant cyanobacterium Aphanothece halophytica.

    PubMed

    Bualuang, Aporn; Incharoensakdi, Aran

    2015-02-01

    Alkaliphilic halotolerant cyanobacterium Aphanothece halophytica showed optimal growth in the medium containing 0.5 M NaCl. The increase of exogenously added glycine to the medium up to 10 mM significantly promoted cell growth under both normal (0.5 M NaCl) a