WorldWideScience

Sample records for parasite growth development

  1. Risk Factors and Relationship Between Intestinal Parasites and the Growth Retardation and Psychomotor Development Delays of Children in Şanlıurfa, Turkey.

    Science.gov (United States)

    Yentur Doni, Nebiye; Yildiz Zeyrek, Fadile; Simsek, Zeynep; Gurses, Gulcan; Sahin, İbrahim

    2015-12-01

    The objective of this study was to determine the risk factors for and relationship among parasitic infections, growth retardation, and psychomotor developmental delays in children aged 6 years and below. This case-control study was performed in Şanlıurfa in southeastern Turkey between October and December 2007. Data were collected using a structured questionnaire, anthropometry, Ankara Development Screening Inventory, and laboratory analysis of stool specimens. The most common parasite was Giardia intestinalis (42.53%) followed by Enterobius vermicularis (27.58%), Ascaris lumbricoides (18.39%), Hymenolepis nana (5.75%), Trichuris trichiura (3.45%), Escherichia coli (1.15%), and Blastocystis spp. (1.15%). Fifty-eight percent of all children were infected with intestinal parasites; 55.2% had only one parasite, whereas 44.8% had multiple parasites. The children infected with G. intestinalis and other intestinal parasites had significantly higher levels of growth retardation and psychomotor development delay than non-infected children. Children with parasitic infections had growth delay up to 2.9 times, general development delay up to 1.9 times, language-cognitive development delay up to 2.2 times, and fine motor development delay up to 2.9 times higher than children without any parasitic infections. However, no significant relationship among intestinal parasites, gross motor development, social-self skills, and development delay was identified. The education level of parents, poor economic situation, number of households, not washing hands, playing with soil, family history of parasitic infection were the significant risk factors for intestinal parasites. Our study indicates that the presence of either malnutrition or intestinal parasites may put a child in a high-risk group for developmental delays and growth retardation. Therefore, public health interventions can embrace nationwide deworming in children.

  2. Development of growth rate measuring method for intracellular, parasitic acid-fast bacteria using radioisotopes

    International Nuclear Information System (INIS)

    Nakata, Noboru; Fukutomi, Yasuo

    1998-01-01

    To prevent and treat infections diseases caused by pathogenic acid-fast bacteria such as Mycobacterium leprae, Tubercle bacillus, it is important to elucidate the mechanisms of intracellular proliferations of these bacteria. This research project was started to make DNA library using a new constructed shuttle vector. Development of in vitro evaluation method for intracellular proliferation of mycobacterium and its transformed cells was attempted on the basis of Buddemeyer method. This method was able to precisely determine the metabolic activities as low as those in leprae and its modified method using 14 C-palmitic acid was highly sensitive and the results were obtainable in a shorter period. The generated CO 2 was satisfactorily absorbed into scintillator without using a filter paper. A new culture medium from which arginine, a NO-producing compound was eliminated was used to repress the sterilizing effects of NO, but the metabolic activities of leprae was not enhanced. (M.N.)

  3. Development of growth rate measuring method for intracellular, parasitic acid-fast bacteria using radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Noboru; Fukutomi, Yasuo [National Inst. of Infectious Deseases, Tokyo (Japan)

    1998-02-01

    To prevent and treat infections diseases caused by pathogenic acid-fast bacteria such as Mycobacterium leprae, Tubercle bacillus, it is important to elucidate the mechanisms of intracellular proliferations of these bacteria. This research project was started to make DNA library using a new constructed shuttle vector. Development of in vitro evaluation method for intracellular proliferation of mycobacterium and its transformed cells was attempted on the basis of Buddemeyer method. This method was able to precisely determine the metabolic activities as low as those in leprae and its modified method using {sup 14}C-palmitic acid was highly sensitive and the results were obtainable in a shorter period. The generated CO{sub 2} was satisfactorily absorbed into scintillator without using a filter paper. A new culture medium from which arginine, a NO-producing compound was eliminated was used to repress the sterilizing effects of NO, but the metabolic activities of leprae was not enhanced. (M.N.)

  4. Ned-19 inhibition of parasite growth and multiplication suggests a role for NAADP mediated signalling in the asexual development of Plasmodium falciparum.

    Science.gov (United States)

    Suárez-Cortés, Pablo; Gambara, Guido; Favia, Annarita; Palombi, Fioretta; Alano, Pietro; Filippini, Antonio

    2017-09-12

    Although malaria is a preventable and curable human disease, millions of people risk to be infected by the Plasmodium parasites and to develop this illness. Therefore, there is an urgent need to identify new anti-malarial drugs. Ca 2+ signalling regulates different processes in the life cycle of Plasmodium falciparum, representing a suitable target for the development of new drugs. This study investigated for the first time the effect of a highly specific inhibitor of nicotinic acid adenine dinucleotide phosphate (NAADP)-induced Ca 2+ release (Ned-19) on P. falciparum, revealing the inhibitory effect of this compound on the blood stage development of this parasite. Ned-19 inhibits both the transition of the parasite from the early to the late trophozoite stage and the ability of the late trophozoite to develop to the multinucleated schizont stage. In addition, Ned-19 affects spontaneous intracellular Ca 2+ oscillations in ring and trophozoite stage parasites, suggesting that the observed inhibitory effects may be associated to regulation of intracellular Ca 2+ levels. This study highlights the inhibitory effect of Ned-19 on progression of the asexual life cycle of P. falciparum. The observation that Ned-19 inhibits spontaneous Ca 2+ oscillations suggests a potential role of NAADP in regulating Ca 2+ signalling of P. falciparum.

  5. Impacts of parasites in early life: contrasting effects on juvenile growth for different family members.

    Directory of Open Access Journals (Sweden)

    Thomas E Reed

    Full Text Available Parasitism experienced early in ontogeny can have a major impact on host growth, development and future fitness, but whether siblings are affected equally by parasitism is poorly understood. In birds, hatching asynchrony induced by hormonal or behavioural mechanisms largely under parental control might predispose young to respond to infection in different ways. Here we show that parasites can have different consequences for offspring depending on their position in the family hierarchy. We experimentally treated European Shag (Phalacrocorax aristoteli nestlings with the broad-spectrum anti-parasite drug ivermectin and compared their growth rates with nestlings from control broods. Average growth rates measured over the period of linear growth (10 days to 30 days of age and survival did not differ for nestlings from treated and control broods. However, when considering individuals within broods, parasite treatment reversed the patterns of growth for individual family members: last-hatched nestlings grew significantly slower than their siblings in control nests but grew faster in treated nests. This was at the expense of their earlier-hatched brood-mates, who showed an overall growth rate reduction relative to last-hatched nestlings in treated nests. These results highlight the importance of exploring individual variation in the costs of infection and suggest that parasites could be a key factor modulating within-family dynamics, sibling competition and developmental trajectories from an early age.

  6. Glutathione-deficient Plasmodium berghei parasites exhibit growth delay and nuclear DNA damage.

    Science.gov (United States)

    Padín-Irizarry, Vivian; Colón-Lorenzo, Emilee E; Vega-Rodríguez, Joel; Castro, María Del R; González-Méndez, Ricardo; Ayala-Peña, Sylvette; Serrano, Adelfa E

    2016-06-01

    Plasmodium parasites are exposed to endogenous and exogenous oxidative stress during their complex life cycle. To minimize oxidative damage, the parasites use glutathione (GSH) and thioredoxin (Trx) as primary antioxidants. We previously showed that disruption of the Plasmodium berghei gamma-glutamylcysteine synthetase (pbggcs-ko) or the glutathione reductase (pbgr-ko) genes resulted in a significant reduction of GSH in intraerythrocytic stages, and a defect in growth in the pbggcs-ko parasites. In this report, time course experiments of parasite intraerythrocytic development and morphological studies showed a growth delay during the ring to schizont progression. Morphological analysis shows a significant reduction in size (diameter) of trophozoites and schizonts with increased number of cytoplasmic vacuoles in the pbggcs-ko parasites in comparison to the wild type (WT). Furthermore, the pbggcs-ko mutants exhibited an impaired response to oxidative stress and increased levels of nuclear DNA (nDNA) damage. Reduced GSH levels did not result in mitochondrial DNA (mtDNA) damage or protein carbonylations in neither pbggcs-ko nor pbgr-ko parasites. In addition, the pbggcs-ko mutant parasites showed an increase in mRNA expression of genes involved in oxidative stress detoxification and DNA synthesis, suggesting a potential compensatory mechanism to allow for parasite proliferation. These results reveal that low GSH levels affect parasite development through the impairment of oxidative stress reduction systems and damage to the nDNA. Our studies provide new insights into the role of the GSH antioxidant system in the intraerythrocytic development of Plasmodium parasites, with potential translation into novel pharmacological interventions. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Parasitic Infections In A Developing Country: The Vermiform ...

    African Journals Online (AJOL)

    The vermiform appendix may become a yielding target and an innocent victim of intestinal parasitism. This is likely to occur more readily in those parts of the developing world in which the parasitic load in the community is high. This high parasitic load more commonly afflicts people of low socio-economic class. This report is ...

  8. Parasites

    Centers for Disease Control (CDC) Podcasts

    2010-05-06

    In this podcast, a listener wants to know what to do if he thinks he has a parasite or parasitic disease.  Created: 5/6/2010 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 5/6/2010.

  9. Gastrointestinal parasite control during prepuberty improves mammary parenchyma development in Holstein heifers

    OpenAIRE

    Perri, AF; Mejía, ME; Licoff, N; Diab, SS; Formía, N; Ornstein, A; Becú-Villalobos, D; Lacau-Mengido, IM

    2013-01-01

    Parasitism during development impairs normal growth and delays the onset of puberty through altered hormone profiles, including insulin-like growth factor one (IGF-1).Asmammary gland development during prepuberty is strongly dependent on IGF-1, we determined if antiparasitic treatment during this stage of growth improved mammary gland development. One group of Holstein heifers was treated monthly, rotationally with antiparasitic drugs from birth to 70 weeks of age, a secon...

  10. Growth strategies of passerine birds are related to brood parasitism by the brown-headed cowbird (Molothrus ater).

    Science.gov (United States)

    Remes, Vladimír

    2006-08-01

    Sibling competition was proposed as an important selective agent in the evolution of growth and development. Brood parasitism by the brown-headed cowbird (Molothrus ater) intensifies sibling competition in the nests of its hosts by increasing host chick mortality and exposing them to a genetically unrelated nestmate. Intranest sibling competition for resources supplied by parents is size dependent. Thus, it should select for high development rates and short nestling periods, which would alleviate negative impacts of brood parasitic chicks on host young. I tested these predictions on 134 North American passerines by comparative analyses. After controlling for covariates and phylogeny, I showed that high parasitism rate was associated with higher nestling growth rate, lower mass at fledging, and shorter nestling periods. These effects were most pronounced in species in which sibling competition is most intense (i.e., weighing over about 30 g). When species were categorized as nonhosts versus old hosts (parasitized for thousands of years) versus new hosts (parasitized the last 100-200 years), there was a clear effect of this parasitism category on growth strategies. Nestling growth rate was the most evolutionarily flexible trait, followed by mass at fledging and nestling period duration. Adjustments during incubation (incubation period length, egg volume) were less pronounced and generally disappeared after controlling for phylogeny. I show that sibling competition caused by brood parasites can have strong effects on the evolution of host growth strategies and that the evolution of developmental traits can take place very rapidly. Human alteration of habitats causing spread of brood parasites to new areas thus cascades into affecting the evolution of life-history traits in host species.

  11. Development of a method to measure intracellular growth rate of parasitic acid-fast bacteria using radio-isotope and its improvement

    International Nuclear Information System (INIS)

    Nakata, Noboru; Fukutomi, Yasuo

    1999-01-01

    Development of measurement method for intracellular growth rate was attempted using gene-transfected acid-fast bacteria and Mycobacterium leprae. M. leprae was inoculated into a well, which was filled with fetus bovine serum containing a cover slip pasted with mouse monocyte-derived malignant cell lines, J774 and P388D1 and cultured for 3-4 hours. Then, the cells on the cover slip were mobilized with 0.1 N NaOH. The metabolic activity of M. leprae was assessed based on the β-oxidation activity of 14 C-palmitic acid. Then, it was investigated whether TNF is produced by the cell culture added with M. leprae or LPS. J774 cells abundantly produced TNF after sensitization with LPS and its production was depending on the amount of added bacteria, whereas TNF production after sensitization with LPS or M. leprae was little in P388D1 cells. Staining for acid-fast bacteria revealed that either of these cell lines has phagocytic activity for M. leprae. To identify the bacterial factor involved to the intracellular proliferation of acid-fast bacteria, transposon insertion mutagenesis was attempted to M. avium complex (MAC) and the degrees of drug-resistance in M. avium mino, M. intracellulare JATA-52 and 8 clinically isolated M. intracellulare strains were determined. M. intracellulare JATA-52 was resistant to kanamycin and plasmid pAL8 and pYT937 were both able to transform the strain with dose-dependency. Since M. intracellulare is pathogenic to human and the strain proliferates with a generation time shorter than that of M. tuberculosis, the former strain is thought suitable for the analysis of a mutated gene. Thus, it became possible to study transposition insertion mutagenesis in M. intracellulare. (M.N.)

  12. Development of a method to measure intracellular growth rate of parasitic acid-fast bacteria using radio-isotope and its improvement

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Noboru; Fukutomi, Yasuo [National Inst. of Infectious Diseases, Tokyo (Japan)

    1999-02-01

    Development of measurement method for intracellular growth rate was attempted using gene-transfected acid-fast bacteria and Mycobacterium leprae. M. leprae was inoculated into a well, which was filled with fetus bovine serum containing a cover slip pasted with mouse monocyte-derived malignant cell lines, J774 and P388D1 and cultured for 3-4 hours. Then, the cells on the cover slip were mobilized with 0.1 N NaOH. The metabolic activity of M. leprae was assessed based on the {beta}-oxidation activity of {sup 14}C-palmitic acid. Then, it was investigated whether TNF is produced by the cell culture added with M. leprae or LPS. J774 cells abundantly produced TNF after sensitization with LPS and its production was depending on the amount of added bacteria, whereas TNF production after sensitization with LPS or M. leprae was little in P388D1 cells. Staining for acid-fast bacteria revealed that either of these cell lines has phagocytic activity for M. leprae. To identify the bacterial factor involved to the intracellular proliferation of acid-fast bacteria, transposon insertion mutagenesis was attempted to M. avium complex (MAC) and the degrees of drug-resistance in M. avium mino, M. intracellulare JATA-52 and 8 clinically isolated M. intracellulare strains were determined. M. intracellulare JATA-52 was resistant to kanamycin and plasmid pAL8 and pYT937 were both able to transform the strain with dose-dependency. Since M. intracellulare is pathogenic to human and the strain proliferates with a generation time shorter than that of M. tuberculosis, the former strain is thought suitable for the analysis of a mutated gene. Thus, it became possible to study transposition insertion mutagenesis in M. intracellulare. (M.N.)

  13. Nematode parasites of animals are more prone to develop xenobiotic resistance than nematode parasites of plants

    Directory of Open Access Journals (Sweden)

    Silvestre A.

    2004-06-01

    Full Text Available In this paper, we concentrate on a comparison of plant and animal-parasitic nematodes, to gain insight into the factors that influence the acquisition of the drug resistance by nematodes. Comparing nematode parasite of domestic animals and cultivated plants, it appears that drug resistance threatens only domestic animal production. Does the paucity of report on nematicide field resistance reflect reality or, is nematicide resistance bypassed by other management practices, specific to cultivated plants (i.e. agricultural control ? First, it seems that selection pressure by treatments in plants is not as efficient as selection pressure in ruminants. Agronomic practices (i.e. sanitation, early planting, usage of nematodes resistant cultivar and crop rotation are frequently used to control parasitic-plant nematodes. Although the efficiency of such measures is generally moderate to high, integrated approaches are developing successfully in parasitic-plant nematode models. Secondly, the majority of anthelmintic resistance cases recorded in animal-parasitic nematodes concern drug families that are not used in plant-parasitic nematodes control (i.e. benzimidazoles, avermectines and levamisole. Thirdly, particular life traits of parasitic-plant nematodes (low to moderate fecundity and reproductive strategy are expected to reduce probability of appearance and transmission of drug resistance genes. It has been demonstrated that, for a large number of nematodes such as Meloidogyne spp., the mode of reproduction by mitotic parthenogenesis reduced genetic diversity of populations which may prevent a rapid drug resistance development. In conclusion, anthelmintic resistance develops in nematode parasite of animals as a consequence of an efficient selection pressure. Early detection of anthelmintic resistance is then crucial : it is not possible to avoid it, but only to delay its development in farm animal industry.

  14. Signaling in Parasitic Nematodes: Physicochemical Communication Between Host and Parasite and Endogenous Molecular Transduction Pathways Governing Worm Development and Survival.

    Science.gov (United States)

    Lok, James B

    2016-12-01

    Signaling or communication between host and parasite may occur over relatively long ranges to enable host finding and acquisition by infective parasitic nematode larvae. Innate behaviors in infective larvae transmitted from the soil that enhance the likelihood of host contact, such as negative geotaxis and hypermotility, are likely mediated by mechanoreception and neuromuscular signaling. Host cues such as vibration of the substratum, elevated temperature, exhaled CO 2 , and other volatile odorants are perceived by mechanosensory and chemosensory neurons of the amphidial complex. Beyond this, the molecular systems that transduce these external cues within the worm are unknown at this time. Overall, the signal transduction mechanisms that regulate switching between dauer and continuous reproductive development in Caenorhabditis elegans , and doubtless other free-living nematodes, have provided a useful framework for testing hypotheses about how the morphogenesis and development of infective parasitic nematode larvae and the lifespan of adult parasites are regulated. In C. elegans , four major signal transduction pathways, G protein-coupled receptor signaling, insulin/insulin-like growth factor signaling, TGFβ-like signaling and steroid-nuclear hormone receptor signaling govern the switch between dauer and continuous development and regulate adult lifespan. Parasitic nematodes appear to have conserved the functions of G-protein-coupled signaling, insulin-like signaling and steroid-nuclear hormone receptor signaling to regulate larval development before and during the infective process. By contrast, TGFβ-like signaling appears to have been adapted for some other function, perhaps modulation of the host immune response. Of the three signal transduction pathways that appear to regulate development in parasitic nematodes, steroid-nuclear hormone signaling is the most straightforward to manipulate with administered small molecules and may form the basis of new

  15. Leishmania development in sand flies: parasite-vector interactions overview.

    Science.gov (United States)

    Dostálová, Anna; Volf, Petr

    2012-12-03

    Leishmaniases are vector-borne parasitic diseases with 0.9 - 1.4 million new human cases each year worldwide. In the vectorial part of the life-cycle, Leishmania development is confined to the digestive tract. During the first few days after blood feeding, natural barriers to Leishmania development include secreted proteolytic enzymes, the peritrophic matrix surrounding the ingested blood meal and sand fly immune reactions. As the blood digestion proceeds, parasites need to bind to the midgut epithelium to avoid being excreted with the blood remnant. This binding is strictly stage-dependent as it is a property of nectomonad and leptomonad forms only. While the attachment in specific vectors (P. papatasi, P. duboscqi and P. sergenti) involves lipophosphoglycan (LPG), this Leishmania molecule is not required for parasite attachment in other sand fly species experimentally permissive for various Leishmania. During late-stage infections, large numbers of parasites accumulate in the anterior midgut and produce filamentous proteophosphoglycan creating a gel-like plug physically obstructing the gut. The parasites attached to the stomodeal valve cause damage to the chitin lining and epithelial cells of the valve, interfering with its function and facilitating reflux of parasites from the midgut. Transformation to metacyclic stages highly infective for the vertebrate host is the other prerequisite for effective transmission. Here, we review the current state of knowledge of molecular interactions occurring in all these distinct phases of parasite colonization of the sand fly gut, highlighting recent discoveries in the field.

  16. Normal growth and development

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002456.htm Normal growth and development To use the sharing features on this page, please enable JavaScript. A child's growth and development can be divided into four periods: ...

  17. [Effects of Cuscuta australis parasitism on the growth, reproduction and defense of Solidago canadensis].

    Science.gov (United States)

    Yang, Bei-fen; Du, Le-shan; Li, Jun-min

    2015-11-01

    In order to find out how parasitic Cuscuta australis influences the growth and reproduction of Solidago canadensis, the effects of the parasitism of C. australis on the morphological, growth and reproductive traits of S. canadensis were examined and the relationships between the biomass and the contents of the secondary metabolites were analyzed. The results showed that the parasitism significantly reduced the plant height, basal diameter, root length, root diameter, root biomass, stem biomass, leaf biomass, total biomass, number of inflorescences branches, axis length of inflorescence, and number of inflorescence. In particular, plant height, number of inflorescence and the stem biomass of parasitized S. canadensis were only 1/2, 1/5 and 1/8 of non-parasitized plants, respectively. There was no significant difference of plant height, root length, stem biomass and total biomass between plants parasitized with high and low intensities. But the basal diameter, root volume, leaf biomass, root biomass, the number of inflorescences branches, axis length of inflorescence and number of inflorescence of S. canadensis parasitized with high intensity were significantly lower than those of plants parasitized with low intensity. The parasitism of C. australis significantly increased the tannins content in the root and the flavonoids content in the stem of S. canadensis. The biomass of S. canadensis was significantly negatively correlated with the tannin content in the root and the flavonoids content in the stem. These results indicated that the parasitism of C. australis could inhibit the growth of S. canadensis by changing the resources allocation patterns as well as reducing the resources obtained by S. canadensis.

  18. Traffic pathways of Plasmodium vivax antigens during intraerythrocytic parasite development.

    Science.gov (United States)

    Bracho, Carmen; Dunia, Irene; De, La Rosa Mercedes; Benedetti, Ennio-Lucio; Perez, Hilda A

    2002-03-01

    We investigated the secretory traffic of a Plasmodium vivax antigen (Pv-148) synthesised by the parasite during the blood cycle, exported into the host cell cytosol and then transported to the surface membrane of the infected erythrocyte. Studies of the ultrastructure of erythrocytes infected with P. vivax showed that intracellular schizogony is accompanied by the generation of parasite-induced membrane profiles in the erythrocyte cytoplasm. These structures are detectable soon after the parasite invades the erythrocyte and develop an elaborate organisation, leading to a tubovesicular membrane (TVM) network, in erythrocytes infected with mature trophozoites. Interestingly, the clefts formed stacked, flattened cisternae resembling a classical Golgi apparatus. The TVM network stained with the fluorescent Golgi marker Bodipy-ceramide. Specific immunolabelling showed that Pv-148 was transferred from the parasite to the erythrocyte surface membrane via the clefts and the TVM network. These findings suggest that the TVM network is part of the secretory pathways involved in parasite protein transport across the Plasmodium-infected erythrocyte and that Pv- 148 may represent a marker that links the parasite with the host cell cytoplasm and, in turn, with the extracellular milieu.

  19. Inhibitory effect of apicidin on in vitro and in vivo growth of Babesia parasites

    OpenAIRE

    Munkhjargal, T; Aboulaila, M.R.A; Sivakumar, T; Yokoyama, Naoaki; Igarashi, Ikuo

    2009-01-01

    Apicidin, a histone deacetylase inhibitor, has a broad spectrum of anti-protozoal activities against apicomplexan parasites. In the present study, we evaluated the inhibitory effect of apicidin on the asexual growth of bovine Babesia parasites (B. bovis and B. bigemina) in vitro, as well as on the in vivo growth of B. microti in mice. The growth of B. bovis and B. bigemina was significantly inhibited in the presence of 3 ng/ml apicidin. Complete inhibition of B. bovis and B. bigemina growth w...

  20. Parasitic castration, growth, and sex steroids in the freshwater bonefish Cyphocharax gilbert (Curimatidae infested by Riggia paranensis (Cymothoidea

    Directory of Open Access Journals (Sweden)

    Neuza R. W. Lima

    Full Text Available Cyphocharax gilbert shows parasitic castration when infested by the crustacean Riggia paranensis, being unable to reproduce. Fish were sampled in the middle rio Itabapoana, Brazil, to study the prevalence of parasitism, growth, and sex steroid concentrations, considering the body size, sex, and reproductive condition of specimens. Most of the fish analyzed were infested (56.0%. The presence of two lines on the scales was more frequent among infested fish (22.0% than among fish without parasites (12.0% for females and 10.0% for males. The occurrence of three lines on the scales was rare (3.5% among infested and 2.0% among females without parasites. These results suggest that growth of the host is faster than that of non infested fish. The serum concentrations of sex steroids from fish without parasites varied at different gonadal development stages (17 beta-estradiol: 60.0 to 976.7 pg/ml; total testosterone: 220.0 to 3,887.7 pg/ml. All infested fish had lower levels of the two sex steroids and undeveloped gonads. Sex steroids levels in infested females were close to those in females at post-spawning stages. Total testosterone concentrations of infested males were below those of males at early gonadal maturation stage. These results suggest that R. paranensis reduces the reproductive capacity of C. gilbert by affecting the host endocrine system.

  1. Toddler Growth and Development

    Science.gov (United States)

    ... the AAP Schedule of Well-Child Care Visits . ​​ Toddler Growth & Development Physical Skills Walks alone Pulls toys behind when ... 18 to 23 Month Old Language Delays in Toddlers: Information for Parents ... Physical Appearance and Growth: Your 1 Year Old Physical Appearance and Growth: ...

  2. Schistosoma mansoni infection suppresses the growth of Plasmodium yoelii parasites in the liver and reduces gametocyte infectivity to mosquitoes.

    Directory of Open Access Journals (Sweden)

    Taeko Moriyasu

    2018-01-01

    Full Text Available Malaria and schistosomiasis are major parasitic diseases causing morbidity and mortality in the tropics. Epidemiological surveys have revealed coinfection rates of up to 30% among children in Sub-Saharan Africa. To investigate the impact of coinfection of these two parasites on disease epidemiology and pathology, we carried out coinfection studies using Plasmodium yoelii and Schistosoma mansoni in mice. Malaria parasite growth in the liver following sporozoite inoculation is significantly inhibited in mice infected with S. mansoni, so that when low numbers of sporozoites are inoculated, there is a large reduction in the percentage of mice that go on to develop blood stage malaria. Furthermore, gametocyte infectivity is much reduced in mice with S. mansoni infections. These results have profound implications for understanding the interactions between Plasmodium and Schistosoma species, and have implications for the control of malaria in schistosome endemic areas.

  3. Aid, growth, and development

    DEFF Research Database (Denmark)

    Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

    2010-01-01

    The micro-macro paradox has been revived. Despite broadly positive evaluations at the micro- and meso-levels, recent literature doubts the ability of foreign aid to foster economic growth and development. This paper assesses the aid-growth literature and, taking inspiration from the program...... evaluation literature, we re-examine key hypotheses. In our findings, aid has a positive and statistically significant causal effect on growth over the long run, with confidence intervals conforming to levels suggested by growth theory. Aid remains a key tool for enhancing the development prospects of poor...

  4. Quantitative Analysis of a Parasitic Antiviral Strategy

    OpenAIRE

    Kim, Hwijin; Yin, John

    2004-01-01

    We extended a computer simulation of viral intracellular growth to study a parasitic antiviral strategy that diverts the viral replicase toward parasite growth. This strategy inhibited virus growth over a wide range of conditions, while minimizing host cell perturbations. Such parasitic strategies may inhibit the development of drug-resistant virus strains.

  5. Treatment of erythrocytes with the 2-cys peroxiredoxin inhibitor, Conoidin A, prevents the growth of Plasmodium falciparum and enhances parasite sensitivity to chloroquine.

    Directory of Open Access Journals (Sweden)

    Mariana Brizuela

    Full Text Available The human erythrocyte contains an abundance of the thiol-dependant peroxidase Peroxiredoxin-2 (Prx2, which protects the cell from the pro-oxidant environment it encounters during its 120 days of life in the blood stream. In malarial infections, the Plasmodium parasite invades red cells and imports Prx2 during intraerythrocytic development, presumably to supplement in its own degradation of peroxides generated during cell metabolism, especially hemoglobin (Hb digestion. Here we demonstrate that an irreversible Prx2 inhibitor, Conoidin A (2,3-bis(bromomethyl-1,4-dioxide-quinoxaline; BBMQ, has potent cytocidal activity against cultured P. falciparum. Parasite growth was also inhibited in red cells that were treated with BBMQ and then washed prior to parasite infection. These cells remained susceptible to merozoite invasion, but failed to support normal intraerythrocytic development. In addition the potency of chloroquine (CQ, an antimalarial drug that prevents the detoxification of Hb-derived heme, was significantly enhanced in the presence of BBMQ. CQ IC50 values decreased an order of magnitude when parasites were either co-incubated with BBMQ, or introduced into BBMQ-pretreated cells; these effects were equivalent for both drug-resistant and drug-sensitive parasite lines. Together these results indicate that treatment of red cells with BBMQ renders them incapable of supporting parasite growth and increases parasite sensitivity to CQ. We also propose that molecules such as BBMQ that target host cell proteins may constitute a novel host-directed therapeutic approach for treating malaria.

  6. Pollen extracts and constituent sugars increase growth of a trypanosomatid parasite of bumble bees

    Directory of Open Access Journals (Sweden)

    Evan C. Palmer-Young

    2017-05-01

    Full Text Available Phytochemicals produced by plants, including at flowers, function in protection against plant diseases, and have a long history of use against trypanosomatid infection. Floral nectar and pollen, the sole food sources for many species of insect pollinators, contain phytochemicals that have been shown to reduce trypanosomatid infection in bumble and honey bees when fed as isolated compounds. Nectar and pollen, however, consist of phytochemical mixtures, which can have greater antimicrobial activity than do single compounds. This study tested the hypothesis that pollen extracts would inhibit parasite growth. Extracts of six different pollens were tested for direct inhibitory activity against cell cultures of the bumble bee trypanosomatid gut parasite Crithidia bombi. Surprisingly, pollen extracts increased parasite growth rather than inhibiting it. Pollen extracts contained high concentrations of sugars, mainly the monosaccharides glucose and fructose. Experimental manipulations of growth media showed that supplemental monosaccharides (glucose and fructose increased maximum cell density, while a common floral phytochemical (caffeic acid with inhibitory activity against other trypanosomatids had only weak inhibitory effects on Crithidia bombi. These results indicate that, although pollen is essential for bees and other pollinators, pollen may promote growth of intestinal parasites that are uninhibited by pollen phytochemicals and, as a result, can benefit from the nutrients that pollen provides.

  7. Growth of the fish parasite Ichthyophonus hoferi under food relevant conditions

    DEFF Research Database (Denmark)

    Spanggaard, Bettina; Huss, Hans Henrik

    1996-01-01

    The physical and chemical limits for growth of the internal fish parasite, Ichthyophonus hoferi, have been studied to understand better the ecology of I. hoferi both as a possible food contaminant and a fish pathogen. The effect of temperature (0 degrees-30 degrees C), pH (3-7) and NaCl (0%-10%w...

  8. Trophic Relationships between the Parasitic Plant Species Phelipanche ramosa (L.) and Different Hosts Depending on Host Phenological Stage and Host Growth Rate

    Science.gov (United States)

    Moreau, Delphine; Gibot-Leclerc, Stéphanie; Girardin, Annette; Pointurier, Olivia; Reibel, Carole; Strbik, Florence; Fernández-Aparicio, Mónica; Colbach, Nathalie

    2016-01-01

    Phelipanche ramosa (L.) Pomel (branched broomrape) is a holoparasitic plant that reproduces on crops and also on weeds, which contributes to increase the parasite seed bank in fields. This parasite extracts all its nutrients at the host’s expense so that host–parasite trophic relationships are crucial to determine host and parasite growth. This study quantified the intensity with which P. ramosa draws assimilates from its host and analyzed whether it varied with host species, host phenological stage and host growth rate. A greenhouse experiment was conducted on three host species: the crop species Brassica napus (L.) (oilseed rape) and two weed species, Capsella bursa-pastoris (L.) Medik. and Geranium dissectum (L.). Plants were grown with or without P. ramosa and under three light levels to modulate host growth rate. The proportion of host biomass loss due to parasitism by P. ramosa differed between host species (at host fructification, biomass loss ranged from 34 to 84%). B. napus and C. bursa-pastoris displayed a similar response to P. ramosa, probably because they belong to the same botanical family. The sensitivity to P. ramosa in each host species could be related to the precocity of P. ramosa development on them. Host compartments could be ranked as a function of their sensitivity to parasitism, with the reproductive compartment being the most severely affected, followed by stems and roots. The proportion of biomass allocated to leaves was not reduced by parasitism. The proportion of pathosystem biomass allocated to the parasite depended on host species. It generally increased with host stage progression but was constant across light induced-host growth rate, showing that P. ramosa adapts its growth to host biomass production. The rank order of host species in terms of sink strength differed from that in terms of host sensitivity. Finally, for B. napus, the biomass of individual parasite shoots decreased with increasing their number per host plant

  9. Trophic relationships between the parasitic plant species Phelipanche ramosa (L. and different hosts depending on host phenological stage and host growth rate

    Directory of Open Access Journals (Sweden)

    Delphine Moreau

    2016-07-01

    Full Text Available Phelipanche ramosa (L. Pomel (branched broomrape is a holoparasitic plant that reproduces on crops and also on weeds, which contributes to increase the parasite seed bank in fields. This parasite extracts all its nutrients at the host's expense so that host-parasite trophic relationships are crucial to determine host and parasite growth. This study quantified the intensity with which P. ramosa draws assimilates from its host and analyzed whether it varied with host species, host phenological stage and host growth rate. A greenhouse experiment was conducted on three host species: the crop species Brassica napus (L. (oilseed rape and two weed species, Capsella bursa-pastoris (L. Medik. and Geranium dissectum (L.. Plants were grown with or without P. ramosa and under three light levels to modulate host growth rate. The proportion of host biomass loss due to parasitism by P. ramosa differed between host species (at host fructification, biomass loss ranged from 34% to 84%. Brassica napus and C. bursa-pastoris displayed a similar response to P. ramosa, probably because they belong to the same botanical family. The sensitivity to P. ramosa in each host species could be related to the precocity of P. ramosa development on them. Host compartments could be ranked as a function of their sensitivity to parasitism, with the reproductive compartment being the most severely affected, followed by stems and roots. The proportion of biomass allocated to leaves was not reduced by parasitism. The proportion of pathosystem biomass allocated to the parasite depended on host species. It generally increased with host stage progression but was constant across light induced-host growth rate, showing that P. ramosa adapts its growth to host biomass production. The rank order of host species in terms of sink strength differed from that in terms of host sensitivity. Finally, for B. napus, the biomass of individual parasite shoots decreased with increasing their number per

  10. Inhibition of protein synthesis and malaria parasite development by drug targeting of methionyl-tRNA synthetases.

    Science.gov (United States)

    Hussain, Tahir; Yogavel, Manickam; Sharma, Amit

    2015-04-01

    Aminoacyl-tRNA synthetases (aaRSs) are housekeeping enzymes that couple cognate tRNAs with amino acids to transmit genomic information for protein translation. The Plasmodium falciparum nuclear genome encodes two P. falciparum methionyl-tRNA synthetases (PfMRS), termed PfMRS(cyt) and PfMRS(api). Phylogenetic analyses revealed that the two proteins are of primitive origin and are related to heterokonts (PfMRS(cyt)) or proteobacteria/primitive bacteria (PfMRS(api)). We show that PfMRS(cyt) localizes in parasite cytoplasm, while PfMRS(api) localizes to apicoplasts in asexual stages of malaria parasites. Two known bacterial MRS inhibitors, REP3123 and REP8839, hampered Plasmodium growth very effectively in the early and late stages of parasite development. Small-molecule drug-like libraries were screened against modeled PfMRS structures, and several "hit" compounds showed significant effects on parasite growth. We then tested the effects of the hit compounds on protein translation by labeling nascent proteins with (35)S-labeled cysteine and methionine. Three of the tested compounds reduced protein synthesis and also blocked parasite growth progression from the ring stage to the trophozoite stage. Drug docking studies suggested distinct modes of binding for the three compounds, compared with the enzyme product methionyl adenylate. Therefore, this study provides new targets (PfMRSs) and hit compounds that can be explored for development as antimalarial drugs. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  11. Parasites and steroid hormones: corticosteroid and sex steroid synthesis, their role in the parasite physiology and development.

    Directory of Open Access Journals (Sweden)

    Marta C. Romano

    2015-06-01

    Full Text Available In many cases parasites display highly complex life cycles that include establishment of the larva or adults within host organs, but even in those that have only one host reciprocal intricate interactions occur. A bulk of evidence indicates that steroid hormones influence the development and course of parasitic infections, the host gender susceptibility to the infection and the associate differences in immunological response are good examples of the host-parasite interplay. However, the capacity of these organisms to synthesize their own steroidogenic hormones still has more questions than answers. It is now well known that many parasites synthesize ecdysteroids, but limited information is available on sex steroid and corticosteroid synthesis. This review intends to summarize some of the existing information in the field. In many but not all parasitosis the host hormonal environment determines the susceptibility, the course and severity of parasite infections. In most cases the infection disturbs the host environment, and activate immune responses that finally affect the endocrine system. Furthermore, sex steroids and corticosteroids may also directly modify the parasite reproduction and molting. Available information indicates that parasites synthesize some steroid hormones like ecdysteroids and sex steroids and the presence and activity of related enzymes have been demonstrated. More recently, the synthesis of corticosteroid like compounds has been shown in Taenia solium and tapeworms and in Taenia crassiceps WFU cysticerci. Deeper knowledge of the endocrine properties of parasites will contribute to understand their reproduction and reciprocal interactions with the host, and also may contribute to design tools to combat the infection in some clinical situations.

  12. Dynamic environments of fungus-farming termite mounds exert growth-modulating effects on fungal crop parasites.

    Science.gov (United States)

    Katariya, Lakshya; Ramesh, Priya B; Borges, Renee M

    2018-03-01

    This study investigated for the first time the impact of the internal mound environment of fungus-growing termites on the growth of fungal crop parasites. Mounds of the termite Odontotermes obesus acted as (i) temperature and relative humidity (RH) 'stabilisers' showing dampened daily variation and (ii) 'extreme environments' exhibiting elevated RH and CO 2 levels, compared to the outside. Yet, internal temperatures exhibited seasonal dynamics as did daily and seasonal CO 2 levels. During in situ experiments under termite-excluded conditions within the mound, the growth of the crop parasite Pseudoxylaria was greater inside than outside the mound, i.e., Pseudoxylaria is 'termitariophilic'. Also, ex situ experiments on parasite isolates differing in growth rates and examined under controlled conditions in the absence of termites revealed a variable effect with fungal growth decreasing only under high CO 2 and low temperature conditions, reflecting the in situ parasite growth fluctuations. In essence, the parasite appears to be adapted to survive in the termite mound. Thus the mound microclimate does not inhibit the parasite but the dynamic environmental conditions of the mound affect its growth to varying extents. These results shed light on the impact of animal-engineered structures on parasite ecology, independent of any direct role of animal engineers. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  13. Gastrointestinal parasite control during prepuberty improves mammary parenchyma development in Holstein heifers.

    Science.gov (United States)

    Perri, Adrián F; Mejía, Miguel E; Licoff, Nicolás; Diab, Santiago S; Formía, Néstor; Ornstein, Ana; Becú-Villalobos, Damasia; Lacau-Mengido, Isabel M

    2013-12-06

    Parasitism during development impairs normal growth and delays the onset of puberty through altered hormone profiles, including insulin-like growth factor one (IGF-1). As mammary gland development during prepuberty is strongly dependent on IGF-1, we determined if antiparasitic treatment during this stage of growth improved mammary gland development. One group of Holstein heifers was treated monthly, rotationally with antiparasitic drugs from birth to 70 weeks of age, a second group was untreated. Treated heifer calves had between 56% and 65% less EPG counts than untreated ones. Presence of Ostertagia, Cooperia, Haemonchus and Trichostrongylus was demonstrated. Treatment effectively advanced the onset of puberty and increased IGF-1 levels. At 20, 30, 40 and 70 weeks of age biopsies from the mammary gland were taken and histological sections were prepared and stained with hematoxylin-eosin. Pictures were analyzed to compare parenchyma area in relation to total mammary tissue between groups. Mammary samples from treated heifers had higher ratios of parenchyma/total area than untreated ones. As mammary development during prepuberty is crucial for mammary performance during lactation, these results add new evidence to the importance of gastrointestinal parasite control in heifers. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Bot fly parasitism of the red-backed vole: host survival, infection risk, and population growth.

    Science.gov (United States)

    Lemaître, Jérôme; Fortin, Daniel; Montiglio, Pierre-Olivier; Darveau, Marcel

    2009-03-01

    Parasites can play an important role in the dynamics of host populations, but empirical evidence remains sparse. We investigated the role of bot fly (Cuterebra spp.) parasitism in red-backed voles (Myodes gapperi) by first assessing the impacts of the parasite on the probability of vole survival under stressful conditions as well as on the reproductive activity of females. We then identified the main factors driving both the individual risk of infection and the abundance of bot flies inside red-backed voles. Finally, we evaluated the impacts of bot fly prevalence on the growth rate of vole populations between mid-July and mid-August. Thirty-six populations of red-backed voles were sampled in the boreal forest of Québec, Canada. The presence and the abundance of parasites in voles, two host life history traits (sex and body condition), three indices of habitat complexity (tree basal area, sapling basal area, coarse woody debris volume), and vole abundance were considered in models evaluating the effects of bot flies on host populations. We found that the probability of survival of red-backed voles in live traps decreased with bot fly infection. Both the individual risk of infection and the abundance of bot flies in red-backed voles were driven mainly by vole abundance rather than by the two host life history traits or the three variables of habitat complexity. Parasitism had population consequences: bot fly prevalence was linked to a decrease in short-term growth rate of vole populations over the summer. We found that bot flies have the potential to reduce survival of red-backed voles, an effect that may apply to large portions of populations.

  15. A Trypanosoma brucei kinesin heavy chain promotes parasite growth by triggering host arginase activity.

    Directory of Open Access Journals (Sweden)

    Géraldine De Muylder

    2013-10-01

    Full Text Available In order to promote infection, the blood-borne parasite Trypanosoma brucei releases factors that upregulate arginase expression and activity in myeloid cells.By screening a cDNA library of T. brucei with an antibody neutralizing the arginase-inducing activity of parasite released factors, we identified a Kinesin Heavy Chain isoform, termed TbKHC1, as responsible for this effect. Following interaction with mouse myeloid cells, natural or recombinant TbKHC1 triggered SIGN-R1 receptor-dependent induction of IL-10 production, resulting in arginase-1 activation concomitant with reduction of nitric oxide (NO synthase activity. This TbKHC1 activity was IL-4Rα-independent and did not mirror M2 activation of myeloid cells. As compared to wild-type T. brucei, infection by TbKHC1 KO parasites was characterized by strongly reduced parasitaemia and prolonged host survival time. By treating infected mice with ornithine or with NO synthase inhibitor, we observed that during the first wave of parasitaemia the parasite growth-promoting effect of TbKHC1-mediated arginase activation resulted more from increased polyamine production than from reduction of NO synthesis. In late stage infection, TbKHC1-mediated reduction of NO synthesis appeared to contribute to liver damage linked to shortening of host survival time.A kinesin heavy chain released by T. brucei induces IL-10 and arginase-1 through SIGN-R1 signaling in myeloid cells, which promotes early trypanosome growth and favors parasite settlement in the host. Moreover, in the late stage of infection, the inhibition of NO synthesis by TbKHC1 contributes to liver pathogenicity.

  16. Common dietary flavonoids inhibit the growth of the intraerythrocytic malaria parasite

    Directory of Open Access Journals (Sweden)

    Saliba Kevin J

    2008-06-01

    Full Text Available Abstract Background Flavonoids are abundant plant phenolic compounds. More than 6000 have been identified to date, and some have been shown to possess antiparasitic activity. Here we investigate the effects of a range of common dietary flavonoids on the growth of two strains of the human malaria parasite Plasmodium falciparum. Findings A chloroquine-sensitive (3D7 and a chloroquine-resistant (7G8 strain of P. falciparum were tested for in vitro susceptibility to a range of individual dietary flavonoids and flavonoid combinations. Parasite susceptibility was measured in 96-well plates over 96 h using a previously described [3H]hypoxanthine incorporation assay. Of the eleven flavonoids tested, eight showed antiplasmodial activity against the 3D7 strain (with IC50 values between 11 and 66 μM, and all showed activity against the 7G8 strain (with IC50 values between 12 and 76 μM. The most active compound against both strains was luteolin, with IC50 values of 11 ± 1 μM and 12 ± 1 μM for 3D7 and 7G8, respectively. Luteolin was found to prevent the progression of parasite growth beyond the young trophozoite stage, and did not affect parasite susceptibility to the antimalarial drugs chloroquine or artemisinin. Combining low concentrations of flavonoids was found to produce an apparent additive antiplasmodial effect. Conclusion Certain common dietary flavonoids inhibit the intraerythrocytic growth of the 3D7 and 7G8 strains of P. falciparum. Flavonoid combinations warrant further investigation as antiplasmodial agents.

  17. Growth, Development and Sustainability

    Directory of Open Access Journals (Sweden)

    Irina-Virginia Dragulanescu

    2013-11-01

    Full Text Available Describing the relationship of interdependence through the materials balance, will be argued how the economy is a subset of the environment and the environment the natural limit to any economic initiative, or the limits imposed by the laws of thermodynamics. The theoretical debate moves, then, from the concept of growth to that of development, understood this in its three dimensions: economic, social, environmental. Bring the different environmental positions in four versions of sustainability, with the gained awareness that it’s “a spectrum of overlapping sustainability positions from very weak to very strong”.

  18. Structural specificity of chloroquine-hematin binding related to inhibition of hematin polymerization and parasite growth.

    Science.gov (United States)

    Vippagunta, S R; Dorn, A; Matile, H; Bhattacharjee, A K; Karle, J M; Ellis, W Y; Ridley, R G; Vennerstrom, J L

    1999-11-04

    Considerable data now support the hypothesis that chloroquine (CQ)-hematin binding in the parasite food vacuole leads to inhibition of hematin polymerization and parasite death by hematin poisoning. To better understand the structural specificity of CQ-hematin binding, 13 CQ analogues were chosen and their hematin binding affinity, inhibition of hematin polymerization, and inhibition of parasite growth were measured. As determined by isothermal titration calorimetry (ITC), the stoichiometry data and exothermic binding enthalpies indicated that, like CQ, these analogues bind to two or more hematin mu-oxo dimers in a cofacial pi-pi sandwich-type complex. Association constants (K(a)'s) ranged from 0.46 to 2.9 x 10(5) M(-1) compared to 4.0 x 10(5) M(-1) for CQ. Remarkably, we were not able to measure any significant interaction between hematin mu-oxo dimer and 11, the 6-chloro analogue of CQ. This result indicates that the 7-chloro substituent in CQ is a critical structural determinant in its binding affinity to hematin mu-oxo dimer. Molecular modeling experiments reinforce the view that the enthalpically favorable pi-pi interaction observed in the CQ-hematin mu-oxo dimer complex derives from a favorable alignment of the out-of-plane pi-electron density in CQ and hematin mu-oxo dimer at the points of intermolecular contact. For 4-aminoquinolines related to CQ, our data suggest that electron-withdrawing functional groups at the 7-position of the quinoline ring are required for activity against both hematin polymerization and parasite growth and that chlorine substitution at position 7 is optimal. Our results also confirm that the CQ diaminoalkyl side chain, especially the aliphatic tertiary nitrogen atom, is an important structural determinant in CQ drug resistance. For CQ analogues 1-13, the lack of correlation between K(a) and hematin polymerization IC(50) values suggests that other properties of the CQ-hematin mu-oxo dimer complex, rather than its association

  19. Lung growth and development.

    Science.gov (United States)

    Joshi, Suchita; Kotecha, Sailesh

    2007-12-01

    Human lung growth starts as a primitive lung bud in early embryonic life and undergoes several morphological stages which continue into postnatal life. Each stage of lung growth is a result of complex and tightly regulated events governed by physical, environmental, hormonal and genetic factors. Fetal lung liquid and fetal breathing movements are by far the most important determinants of lung growth. Although timing of the stages of lung growth in animals do not mimic that of human, numerous animal studies, mainly on sheep and rat, have given us a better understanding of the regulators of lung growth. Insight into the genetic basis of lung growth has helped us understand and improve management of complex life threatening congenital abnormalities such as congenital diaphragmatic hernia and pulmonary hypoplasia. Although advances in perinatal medicine have improved survival of preterm infants, premature birth is perhaps still the most important factor for adverse lung growth.

  20. Glucosinolates from Host Plants Influence Growth of the Parasitic Plant Cuscuta gronovii and Its Susceptibility to Aphid Feeding.

    Science.gov (United States)

    Smith, Jason D; Woldemariam, Melkamu G; Mescher, Mark C; Jander, Georg; De Moraes, Consuelo M

    2016-09-01

    Parasitic plants acquire diverse secondary metabolites from their hosts, including defense compounds that target insect herbivores. However, the ecological implications of this phenomenon, including the potential enhancement of parasite defenses, remain largely unexplored. We studied the translocation of glucosinolates from the brassicaceous host plant Arabidopsis (Arabidopsis thaliana) into parasitic dodder vines (Convolvulaceae; Cuscuta gronovii) and its effects on the parasite itself and on dodder-aphid interactions. Aliphatic and indole glucosinolates reached concentrations in parasite tissues higher than those observed in corresponding host tissues. Dodder growth was enhanced on cyp79B2 cyp79B3 hosts (without indole glucosinolates) but inhibited on atr1D hosts (with elevated indole glucosinolates) relative to wild-type hosts, which responded to parasitism with localized elevation of indole and aliphatic glucosinolates. These findings implicate indole glucosinolates in defense against parasitic plants. Rates of settling and survival on dodder vines by pea aphids (Acyrthosiphon pisum) were reduced significantly when dodder parasitized glucosinolate-producing hosts (wild type and atr1D) compared with glucosinolate-free hosts (cyp79B2 cyp79B3 myb28 myb29). However, settling and survival of green peach aphids (Myzus persicae) were not affected. M. persicae population growth was actually reduced on dodder parasitizing glucosinolate-free hosts compared with wild-type or atr1D hosts, even though stems of the former contain less glucosinolates and more amino acids. Strikingly, this effect was reversed when the aphids fed directly upon Arabidopsis, which indicates an interactive effect of parasite and host genotype on M. persicae that stems from host effects on dodder. Thus, our findings indicate that glucosinolates may have both direct and indirect effects on dodder-feeding herbivores. © 2016 American Society of Plant Biologists. All rights reserved.

  1. Glucosinolates from Host Plants Influence Growth of the Parasitic Plant Cuscuta gronovii and Its Susceptibility to Aphid Feeding1[OPEN

    Science.gov (United States)

    2016-01-01

    Parasitic plants acquire diverse secondary metabolites from their hosts, including defense compounds that target insect herbivores. However, the ecological implications of this phenomenon, including the potential enhancement of parasite defenses, remain largely unexplored. We studied the translocation of glucosinolates from the brassicaceous host plant Arabidopsis (Arabidopsis thaliana) into parasitic dodder vines (Convolvulaceae; Cuscuta gronovii) and its effects on the parasite itself and on dodder-aphid interactions. Aliphatic and indole glucosinolates reached concentrations in parasite tissues higher than those observed in corresponding host tissues. Dodder growth was enhanced on cyp79B2 cyp79B3 hosts (without indole glucosinolates) but inhibited on atr1D hosts (with elevated indole glucosinolates) relative to wild-type hosts, which responded to parasitism with localized elevation of indole and aliphatic glucosinolates. These findings implicate indole glucosinolates in defense against parasitic plants. Rates of settling and survival on dodder vines by pea aphids (Acyrthosiphon pisum) were reduced significantly when dodder parasitized glucosinolate-producing hosts (wild type and atr1D) compared with glucosinolate-free hosts (cyp79B2 cyp79B3 myb28 myb29). However, settling and survival of green peach aphids (Myzus persicae) were not affected. M. persicae population growth was actually reduced on dodder parasitizing glucosinolate-free hosts compared with wild-type or atr1D hosts, even though stems of the former contain less glucosinolates and more amino acids. Strikingly, this effect was reversed when the aphids fed directly upon Arabidopsis, which indicates an interactive effect of parasite and host genotype on M. persicae that stems from host effects on dodder. Thus, our findings indicate that glucosinolates may have both direct and indirect effects on dodder-feeding herbivores. PMID:27482077

  2. Advanced dendritic web growth development

    Science.gov (United States)

    Hopkins, R. H.

    1985-01-01

    A program to develop the technology of the silicon dendritic web ribbon growth process is examined. The effort is being concentrated on the area rate and quality requirements necessary to meet the JPL/DOE goals for terrestrial PV applications. Closed loop web growth system development and stress reduction for high area rate growth is considered.

  3. Factors influencing growth and intestinal parasitic infections in preschoolers attending philanthropic daycare centers in Salvador, Northeast Region of Brazil.

    Science.gov (United States)

    Lander, Rebecca L; Lander, Alastair G; Houghton, Lisa; Williams, Sheila M; Costa-Ribeiro, Hugo; Barreto, Daniel L; Mattos, Angela P; Gibson, Rosalind S

    2012-11-01

    Poor growth and intestinal parasitic infections are widespread in disadvantaged urban children. This cross-sectional study assessed factors influencing poor growth and intestinal parasites in 376 children aged three to six years in daycare centers in Salvador, in the Northeast Region of Brazil. Data was obtained from seven daycare centers on child weight, height, socio-economic status, health and intestinal parasites in stool samples. Prevalence of moderate underweight ( -2SD), wasting and stunting was 12%, 16% and 6% respectively. Socioeconomic status, birth order, and maternal weight were predictors of poor anthropometric status. Almost 30% of children were infected with more than one intestinal parasite. Helminths (17.8%), notably Trichuris trichiura (12%) and Ascaris lumbricoides (10.5%), and protozoan Giardia duodenalis (13%) were the most common types of parasites detected. One percent of children had hookworm and Cryptosporidium sp. and 25% had non-pathogenic protozoan cysts. Boys from families with very low socio-economic status had lower linear growth and presented a greater risk of helminth infection. Deworming is considered an alternative for reducing the prevalence of intestinal parasitic infections in this age group.

  4. Licochalcone A, a new antimalarial agent, inhibits in vitro growth of the human malaria parasite Plasmodium falciparum and protects mice from P. yoelii infection

    DEFF Research Database (Denmark)

    Chen, M; Theander, T G; Christensen, S B

    1994-01-01

    Licochalcone A, isolated from Chinese licorice roots, inhibited the in vitro growth of both chloroquine-susceptible (3D7) and chloroquine-resistant (Dd2) Plasmodium falciparum strains in a [3H]hypoxanthine uptake assay. The growth inhibition of the chloroquine-resistant strain by licochalcone A w...... that licochalcone A exhibits potent antimalarial activity and might be developed into a new antimalarial drug....... A was similar to that of the chloroquine-susceptible strain. To examine the activity of licochalcone A on the different asexual blood stages of the parasite, licochalcone A was added to highly synchronized cultures containing rings, trophozoites, and schizonts. The growth of the parasites at all stages...... was inhibited by licochalcone A. The in vivo activity of licochalcone A was tested in a mouse model of infection with P. yoelii. Licochalcone A administered either intraperitoneally or orally for 3 to 6 days protected the mice from the otherwise lethal P. yoelii infection. These results demonstrate...

  5. Genetic Validation of Leishmania donovani Lysyl-tRNA Synthetase Shows that It Is Indispensable for Parasite Growth and Infectivity.

    Science.gov (United States)

    Chadha, Sanya; Mallampudi, N Arjunreddy; Mohapatra, Debendra K; Madhubala, Rentala

    2017-01-01

    Leishmania donovani is a protozoan parasite that causes visceral leishmaniasis. Increasing resistance and severe side effects of existing drugs have led to the need to identify new chemotherapeutic targets. Aminoacyl-tRNA synthetases (aaRSs) are ubiquitous and are required for protein synthesis. aaRSs are known drug targets for bacterial and fungal pathogens. Here, we have characterized and evaluated the essentiality of L. donovani lysyl-tRNA synthetase ( Ld LysRS). Two different coding sequences for lysyl-tRNA synthetases are annotated in the Leishmania genome database. Ld LysRS-1 (LdBPK_150270.1), located on chromosome 15, is closer to apicomplexans and eukaryotes, whereas Ld LysRS-2 (LdBPK_300130.1), present on chromosome 30, is closer to bacteria. In the present study, we have characterized Ld LysRS-1. Recombinant Ld LysRS-1 displayed aminoacylation activity, and the protein localized to the cytosol. The Ld LysRS-1 heterozygous mutants had a restrictive growth phenotype and attenuated infectivity. Ld LysRS-1 appears to be an essential gene, as a chromosomal knockout of Ld LysRS-1 could be generated when the gene was provided on a rescuing plasmid. Cladosporin, a fungal secondary metabolite and a known inhibitor of LysRS, was more potent against promastigotes (50% inhibitory concentration [IC 50 ], 4.19 µM) and intracellular amastigotes (IC 50 , 1.09 µM) than were isomers of cladosporin (3-epi-isocladosporin and isocladosporin). These compounds exhibited low toxicity to mammalian cells. The specificity of inhibition of parasite growth caused by these inhibitors was further assessed using Ld LysRS-1 heterozygous mutant strains and rescue mutant promastigotes. These inhibitors inhibited the aminoacylation activity of recombinant Ld LysRS. Our data provide a framework for the development of a new class of drugs against this parasite. IMPORTANCE Aminoacyl-tRNA synthetases are housekeeping enzymes essential for protein translation, providing charged tRNAs for

  6. Aid, Growth, and Development

    DEFF Research Database (Denmark)

    Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

    ) ability to pay, and (iv) level of interaction with public officials. Moreover, when informal firms become formal the probability of paying bribes increases. Becoming formal is also associated with a revenue growth premium that is not driven by self-selection of well-performing firms. On average...

  7. Human Development and Economic Growth

    OpenAIRE

    Ranis, Gustav

    2004-01-01

    Recent literature has contrasted Human Development, described as the ultimate goal of the development process, with economic growth, described as an imperfect proxy for more general welfare, or as a means toward enhanced human development. This debate has broadened the definitions and goals of development but still needs to define the important interrelations between human development (HD) and economic growth (EG). To the extent that greater freedom and capabilities improve economic performan...

  8. Developing principles of growth

    DEFF Research Database (Denmark)

    Neergaard, Helle; Fleck, Emma

    of the principles of growth among women-owned firms. Using an in-depth case study methodology, data was collected from women-owned firms in Denmark and Ireland, as these countries are similar in contextual terms, e.g. population and business composition, dominated by micro, small and medium-sized enterprises....... Extending on principles put forward in effectuation theory, we propose that women grow their firms according to five principles which enable women’s enterprises to survive in the face of crises such as the current financial world crisis....

  9. Leishmania eukaryotic initiation factor (LeIF inhibits parasite growth in murine macrophages.

    Directory of Open Access Journals (Sweden)

    Olga Koutsoni

    Full Text Available The leishmaniases constitute neglected global public health problems that require adequate control measures, prophylactic clinical vaccines and effective and non-toxic drug treatments. In this study, we explored the potential of Leishmania infantum eukaryotic initiation factor (LieIF, an exosomal protein, as a novel anti-infective therapeutic molecule. More specifically, we assessed the efficacy of recombinant LieIF, in combination with recombinant IFN-γ, in eliminating intracellular L. donovani parasites in an in vitro macrophage model. J774A.1 macrophages were initially treated with LieIF/IFN-γ prior to in vitro infection with L. donovani stationary phase promastigotes (pre-infection treatment, and resistance to infection was observed 72 h after infection. J774A.1 macrophages were also treated with LieIF/IFN-γ after L. donovani infection (post-infection treatment, and resistance to infection was also observed at both time points tested (19 h and 72 h after infection. To elucidate the LieIF/IFN-γ-induced mechanism(s that mediate the reduction of intracellular parasite growth, we examined the generation of potent microbicidal molecules, such as nitric oxide (NO and reactive oxygen species (ROS, within infected macrophages. Furthermore, macrophages pre-treated with LieIF/IFN-γ showed a clear up-regulation in macrophage inflammatory protein 1α (MIP-1α as well as tumor necrosis factor alpha (TNF-α expression. However, significant different protein levels were not detected. In addition, macrophages pre-treated with LieIF/IFN-γ combined with anti-TNF-α monoclonal antibody produced significantly lower amounts of ROS. These data suggest that during the pre-treatment state, LieIF induces intramacrophage parasite growth inhibition through the production of TNF-α, which induces microbicidal activity by stimulating NO and ROS production. The mechanisms of NO and ROS production when macrophages are treated with LieIF after infection are probably

  10. Growth and Development

    Science.gov (United States)

    ... Development Infections Diseases & Conditions Pregnancy & Baby Nutrition & Fitness Emotions & Behavior School & Family Life First Aid & Safety Doctors & ... With Preschoolers Encouraging Your Child's Sense of Humor Games for Preschoolers Games for Toddlers Gifted Education Group ...

  11. Scaffold proteins LACK and TRACK as potential drug targets in kinetoplastid parasites: Development of inhibitors

    Directory of Open Access Journals (Sweden)

    Nir Qvit

    2016-04-01

    Full Text Available Parasitic diseases cause ∼500,000 deaths annually and remain a major challenge for therapeutic development. Using a rational design based approach, we developed peptide inhibitors with anti-parasitic activity that were derived from the sequences of parasite scaffold proteins LACK (Leishmania's receptor for activated C-kinase and TRACK (Trypanosoma receptor for activated C-kinase. We hypothesized that sequences in LACK and TRACK that are conserved in the parasites, but not in the mammalian ortholog, RACK (Receptor for activated C-kinase, may be interaction sites for signaling proteins that are critical for the parasites' viability. One of these peptides exhibited leishmanicidal and trypanocidal activity in culture. Moreover, in infected mice, this peptide was also effective in reducing parasitemia and increasing survival without toxic effects. The identified peptide is a promising new anti-parasitic drug lead, as its unique features may limit toxicity and drug-resistance, thus overcoming central limitations of most anti-parasitic drugs. Keywords: Chagas disease, Leishmaniasis, Peptide, LACK, TRACK, Scaffold protein

  12. Identification of loci controlling restriction of parasite growth in experimental Taenia crassiceps cysticercosis.

    Directory of Open Access Journals (Sweden)

    Ruben Ramirez-Aquino

    2011-12-01

    Full Text Available Human neurocysticercosis (NC caused by Taenia solium is a parasitic disease of the central nervous system that is endemic in many developing countries. In this study, a genetic approach using the murine intraperitoneal cysticercosis caused by the related cestode Taenia crassiceps was employed to identify host factors that regulate the establishment and proliferation of the parasite. A/J mice are permissive to T. crassiceps infection while C57BL/6J mice (B6 are comparatively restrictive, with a 10-fold difference in numbers of peritoneal cysticerci recovered 30 days after infection. The genetic basis of this inter-strain difference was explored using 34 AcB/BcA recombinant congenic strains derived from A/J and B6 progenitors, that were phenotyped for T. crassiceps replication. In agreement with their genetic background, most AcB strains (A/J-derived were found to be permissive to infection while most BcA strains (B6-derived were restrictive with the exception of a few discordant strains, together suggesting a possible simple genetic control. Initial haplotype association mapping using >1200 informative SNPs pointed to linkages on chromosomes 2 (proximal and 6 as controlling parasite replication in the AcB/BcA panel. Additional linkage analysis by genome scan in informative [AcB55xDBA/2]F1 and F2 mice (derived from the discordant AcB55 strain, confirmed the effect of chromosome 2 on parasite replication, and further delineated a major locus (LOD = 4.76, p<0.01; peak marker D2Mit295, 29.7 Mb that we designate Tccr1 (T. crassiceps cysticercosis restrictive locus 1. Resistance alleles at Tccr1 are derived from AcB55 and are inherited in a dominant fashion. Scrutiny of the minimal genetic interval reveals overlap of Tccr1 with other host resistance loci mapped to this region, most notably the defective Hc/C5 allele which segregates both in the AcB/BcA set and in the AcB55xDBA/2 cross. These results strongly suggest that the complement component 5 (C5

  13. Identification of Loci Controlling Restriction of Parasite Growth in Experimental Taenia crassiceps Cysticercosis

    Science.gov (United States)

    Fortin, Anny; Sciutto-Conde, Edda; Fragoso-González, Gladis; Gros, Philippe; Aguilar-Delfin, Irma

    2011-01-01

    Human neurocysticercosis (NC) caused by Taenia solium is a parasitic disease of the central nervous system that is endemic in many developing countries. In this study, a genetic approach using the murine intraperitoneal cysticercosis caused by the related cestode Taenia crassiceps was employed to identify host factors that regulate the establishment and proliferation of the parasite. A/J mice are permissive to T. crassiceps infection while C57BL/6J mice (B6) are comparatively restrictive, with a 10-fold difference in numbers of peritoneal cysticerci recovered 30 days after infection. The genetic basis of this inter-strain difference was explored using 34 AcB/BcA recombinant congenic strains derived from A/J and B6 progenitors, that were phenotyped for T. crassiceps replication. In agreement with their genetic background, most AcB strains (A/J-derived) were found to be permissive to infection while most BcA strains (B6-derived) were restrictive with the exception of a few discordant strains, together suggesting a possible simple genetic control. Initial haplotype association mapping using >1200 informative SNPs pointed to linkages on chromosomes 2 (proximal) and 6 as controlling parasite replication in the AcB/BcA panel. Additional linkage analysis by genome scan in informative [AcB55xDBA/2]F1 and F2 mice (derived from the discordant AcB55 strain), confirmed the effect of chromosome 2 on parasite replication, and further delineated a major locus (LOD = 4.76, p<0.01; peak marker D2Mit295, 29.7 Mb) that we designate Tccr1 (T. crassiceps cysticercosis restrictive locus 1). Resistance alleles at Tccr1 are derived from AcB55 and are inherited in a dominant fashion. Scrutiny of the minimal genetic interval reveals overlap of Tccr1 with other host resistance loci mapped to this region, most notably the defective Hc/C5 allele which segregates both in the AcB/BcA set and in the AcB55xDBA/2 cross. These results strongly suggest that the complement component 5 (C5) plays a

  14. [Design and development of an online system of parasite's images for training and evaluation].

    Science.gov (United States)

    Yuan-Chun, Mao; Sui, Xu; Jie, Wang; Hua-Yun, Zhou; Jun, Cao

    2017-08-08

    To design and develop an online training and evaluation system for parasitic pathogen recognition. The system was based on a Parasitic Diseases Specimen Image Digitization Construction Database by using MYSQL 5.0 as the system of database development software, and PHP 5 as the interface development language. It was mainly used for online training and evaluation of parasitic pathology diagnostic techniques. The system interface was designed simple, flexible, and easy to operate for medical staff. It enabled full day and 24 hours accessible to online training study and evaluation. Thus, the system broke the time and space constraints of the traditional training models. The system provides a shared platform for the professional training of parasitic diseases, and a reference for other training tasks.

  15. An interplay between 2 signaling pathways: Melatonin-cAMP and IP3–Ca2+ signaling pathways control intraerythrocytic development of the malaria parasite Plasmodium falciparum

    International Nuclear Information System (INIS)

    Furuyama, Wakako; Enomoto, Masahiro; Mossaad, Ehab; Kawai, Satoru; Mikoshiba, Katsuhiko; Kawazu, Shin-ichiro

    2014-01-01

    Highlights: • A melatonin receptor antagonist blocked Ca 2+ oscillation in P. falciparum and inhibited parasite growth. • P. falciparum development is controlled by Ca 2+ - and cAMP-signaling pathways. • The cAMP-signaling pathway at ring form and late trophozoite stages governs parasite growth of P. falciparum. - Abstract: Plasmodium falciparum spends most of its asexual life cycle within human erythrocytes, where proliferation and maturation occur. Development into the mature forms of P. falciparum causes severe symptoms due to its distinctive sequestration capability. However, the physiological roles and the molecular mechanisms of signaling pathways that govern development are poorly understood. Our previous study showed that P. falciparum exhibits stage-specific spontaneous Calcium (Ca 2+ ) oscillations in ring and early trophozoites, and the latter was essential for parasite development. In this study, we show that luzindole (LZ), a selective melatonin receptor antagonist, inhibits parasite growth. Analyses of development and morphology of LZ-treated P. falciparum revealed that LZ severely disrupted intraerythrocytic maturation, resulting in parasite death. When LZ was added at ring stage, the parasite could not undergo further development, whereas LZ added at the trophozoite stage inhibited development from early into late schizonts. Live-cell Ca 2+ imaging showed that LZ treatment completely abolished Ca 2+ oscillation in the ring forms while having little effect on early trophozoites. Further, the melatonin-induced cAMP increase observed at ring and late trophozoite stage was attenuated by LZ treatment. These suggest that a complex interplay between IP 3 –Ca 2+ and cAMP signaling pathways is involved in intraerythrocytic development of P. falciparum

  16. Reciprocal cross infection of sticklebacks with the diphyllobothriidean cestode Schistocephalus solidus reveals consistent population differences in parasite growth and host resistance.

    Science.gov (United States)

    Kalbe, Martin; Eizaguirre, Christophe; Scharsack, Jörn P; Jakobsen, Per J

    2016-03-08

    In host-parasite evolutionary arms races, parasites are generally expected to adapt more rapidly, due to their large population sizes and short generation times. There exist systems, though, where parasites cannot outpace their hosts because of similar generation times in both antagonists. In those cases concomitant adaptation is expected. We tested this hypothesis in the three-spined stickleback-Schistocephalus solidus tapeworm system, where generation times are comparable in both organisms. We chose two populations of sticklebacks which differ prominently in the prevalence of S. solidus and consequently in its level of selective pressure. We performed a full factorial common garden experiment. Particularly, Norwegian (NO) and German (DE) sticklebacks, as well as hybrids between both stickleback populations and in both parental combinations, were exposed each to a single S. solidus originating from the same two host populations. We found the infection phenotype to depend on the host population, the parasite population, but not their interaction. NO-parasites showed higher infectivity than DE-parasites, with NO-sticklebacks also being more resistant to DE-parasites than to the sympatric NO-parasite. Reciprocally, DE-hosts were more susceptible to the allopatric NO-parasite while DE-parasites grew less than NO-parasites in all stickleback groups. Despite this asymmetry, the ratio of worm to host weight, an indicator of parasite virulence, was identical in both sympatric combinations, suggesting an optimal virulence as a common outcome of parallel coevolved systems. In hybrid sticklebacks, intermediate infection rates and growth of S. solidus from either origin suggests a simple genetic basis of resistance. However, comparison of infection phenotypes in NO-maternal and DE-maternal hybrid sticklebacks indicates local adaptation to the sympatric counterpart in both the host and the parasite. Host-parasite systems with similar generation time show evidence for

  17. Limonene Arrests Parasite Development and Inhibits Isoprenylation of Proteins in Plasmodium falciparum

    Science.gov (United States)

    Moura, Ivan Cruz; Wunderlich, Gerhard; Uhrig, Maria L.; Couto, Alicia S.; Peres, Valnice J.; Katzin, Alejandro M.; Kimura, Emília A.

    2001-01-01

    Isoprenylation is an essential protein modification in eukaryotic cells. Herein, we report that in Plasmodium falciparum, a number of proteins were labeled upon incubation of intraerythrocytic forms with either [3H]farnesyl pyrophosphate or [3H]geranylgeranyl pyrophosphate. By thin-layer chromatography, we showed that attached isoprenoids are partially modified to dolichol and other, uncharacterized, residues, confirming active isoprenoid metabolism in this parasite. Incubation of blood-stage P. falciparum treated with the isoprenylation inhibitor limonene significantly decreased the parasites' progression from the ring stage to the trophozoite stage and at 1.22 mM, 50% of the parasites died after the first cycle. Using Ras- and Rap-specific monoclonal antibodies, putative Rap and Ras proteins of P. falciparum were immunoprecipitated. Upon treatment with 0.5 mM limonene, isoprenylation of these proteins was significantly decreased, possibly explaining the observed arrest of parasite development. PMID:11502528

  18. The transcriptomic changes associated with the development of social parasitism in the honeybee Apis mellifera capensis

    Science.gov (United States)

    Aumer, Denise; Mumoki, Fiona N.; Pirk, Christian W. W.; Moritz, Robin F. A.

    2018-04-01

    Social insects are characterized by the division of labor. Queens usually dominate reproduction, whereas workers fulfill non-reproductive age-dependent tasks to maintain the colony. Although workers are typically sterile, they can activate their ovaries to produce their own offspring. In the extreme, worker reproduction can turn into social parasitism as in Apis mellifera capensis. These intraspecific parasites occupy a host colony, kill the resident queen, and take over the reproductive monopoly. Because they exhibit a queenlike behavior and are also treated like queens by the fellow workers, they are so-called pseudoqueens. Here, we compare the development of parasitic pseudoqueens and social workers at different time points using fat body transcriptome data. Two complementary analysis methods—a principal component analysis and a time course analysis—led to the identification of a core set of genes involved in the transition from a social worker into a highly fecund parasitic pseudoqueen. Comparing our results on pseudoqueens with gene expression data of honeybee queens revealed many similarities. In addition, there was a set of specific transcriptomic changes in the parasitic pseudoqueens that differed from both, queens and social workers, which may be typical for the development of the social parasitism in A. m. capensis.

  19. Laboratory Studies on Molting and Growth of the Shore Crab, Hemigrapsus sanguineus de Haan, Parasitized by a Rhizocephalan Barnacle.

    Science.gov (United States)

    Takahashi, T; Matsuura, S

    1994-06-01

    Molting of shore crabs (Hemigrapsus sanguineus) parasitized by rhizocephalans (Sacculina senta) was observed in the laboratory, and the growth of the molted crabs was compared with that of unparasitized animals. Molting of the host was obstructed by the infestation, but was still possible. After the release of several broods of larvae, the externa (the external reproductive system of the parasite) detached from the host. Subsequent molting occurred within 40 days in about 80% of the animals, but in the remainder, it was delayed for at most 4 months. Soon after molting, a new externa protruded from the abdomen of every crab. Thus, the life-span of the externa and the molting of the host would seem to be closely connected. In the female, the molt frequency was reduced, but the molt increment of the parasitized crabs was not different from that in the unparasitized ones. In the male, however, both the molt frequency and the molt increment were reduced. Thus, the annual growth of parasitized males and females was about half that of unparasitized crabs.

  20. Dynamics of sterol synthesis during development of Leishmania spp. parasites to their virulent form.

    Science.gov (United States)

    Yao, Chaoqun; Wilson, Mary E

    2016-04-12

    The Leishmania spp. protozoa, the causative agents of the "neglected" tropical disease leishmaniasis, are transmitted to mammals by sand fly vectors. Within the sand fly, parasites transform from amastigotes to procyclic promastigotes, followed by development of virulent (metacyclic) promastigote forms. The latter are infectious to mammalian hosts. Biochemical components localized in the parasite plasma membrane such as proteins and sterols play a pivotal role in Leishmania pathogenesis. Leishmania spp. lack the enzymes for cholesterol synthesis, and the dynamics of sterol acquisition and biosynthesis in parasite developmental stages are not understood. We hypothesized that dynamic changes in sterol composition during metacyclogenesis contribute to the virulence of metacyclic promastigotes. Sterols were extracted from logarithmic phase or metacyclic promastigotes grown in liquid culture with or without cholesterol, and analyzed qualitatively and quantitatively by gas chromatograph-mass spectrometry (GC-MS). TriTrypDB was searched for identification of genes involved in Leishmania sterol biosynthetic pathways. In total nine sterols were identified. There were dynamic changes in sterols during promastigote metacyclogenesis. Cholesterol in the culture medium affected sterol composition in different parasite stages. There were qualitative and relative quantitative differences between the sterol content of virulent versus avirulent parasite strains. A tentative sterol biosynthetic pathway in Leishmania spp. promastigotes was identified. Significant differences in sterol composition were observed between promastigote stages, and between parasites exposed to different extracellular cholesterol in the environment. These data lay the foundation for further investigating the role of sterols in the pathogenesis of Leishmania spp. infections.

  1. Survival and growth of parasitic Maculinea alcon caterpillars (Lepidoptera: Lycaenidae) in nests of three Myrmica ant species

    DEFF Research Database (Denmark)

    Nash, D. R.; Als, Thomas Damm; Boomsma, J. J.

    2011-01-01

    The Alcon blue butterfly (Maculinea alcon) parasitizes the nests of several Myrmica ant species. In Denmark, it uses M. rubra and M. ruginodis, but never M. scabrinodis. To further examine the basis of this specificity and local co-adaptation between host and parasite, the pattern of growth...... and survival of newly-adopted caterpillars of M. alcon in Myrmica subcolonies was examined in the laboratory. M. alcon caterpillars were collected from three populations differing in their host use, and reared in laboratory nests of all three ant species collected from each M. alcon population. While...... there were differences in the pattern of growth of caterpillars from different populations during the first few months after adoption, which depended on host ant species and the site from which the ants were collected, there was no evidence of major differences in final size achieved. Survival was, however...

  2. Identification of a secreted casein kinase 1 in Leishmania donovani: effect of protein over expression on parasite growth and virulence.

    Directory of Open Access Journals (Sweden)

    Mary Dan-Goor

    Full Text Available Casein kinase 1 (CK1 plays an important role in eukaryotic signaling pathways, and their substrates include key regulatory proteins involved in cell differentiation, proliferation and chromosome segregation. The Leishmania genome encodes six potential CK1 isoforms, of which five have orthologs in other trypanosomatidae. Leishmania donovani CK1 isoform 4 (Ldck1.4, orthologous to LmjF27.1780 is unique to Leishmania and contains a putative secretion signal peptide. The full-length gene and three shorter constructs were cloned and expressed in E. coli as His-tag proteins. Only the full-length 62.3 kDa protein showed protein kinase activity indicating that the N-terminal and C-terminal domains are essential for protein activity. LdCK1.4-FLAG was stably over expressed in L. donovani, and shown by immunofluorescence to be localized primarily in the cytosol. Western blotting using anti-FLAG and anti-CK1.4 antibodies showed that this CK1 isoform is expressed and secreted by promastigotes. Over expression of LdCK1.4 had a significant effect on promastigote growth in culture with these parasites growing to higher cell densities than the control parasites (wild-type or Ld:luciferase, P<0.001. Analysis by flow cytometry showed a higher percentage, ∼4-5-fold, of virulent metacyclic promastigotes on day 3 among the LdCK1.4 parasites. Finally, parasites over expressing LdCK1.4 gave significantly higher infections of mouse peritoneal macrophages compared to wild-type parasites, 28.6% versus 6.3%, respectively (p = 0.0005. These results suggest that LdCK1.4 plays an important role in parasite survival and virulence. Further studies are needed to validate CK1.4 as a therapeutic target in Leishmania.

  3. Antibodies against the Plasmodium falciparum glutamate-rich protein from naturally exposed individuals living in a Brazilian malaria-endemic area can inhibit in vitro parasite growth

    DEFF Research Database (Denmark)

    Pratt-Riccio, Lilian Rose; Bianco, Cesare; Totino, Paulo Renato Rivas

    2011-01-01

    The glutamate-rich protein (GLURP) is an exoantigen expressed in all stages of the Plasmodium falciparum life cycle in humans. Anti-GLURP antibodies can inhibit parasite growth in the presence of monocytes via antibody-dependent cellular inhibition (ADCI), and a major parasite-inhibitory region h...

  4. Growth charts of human development

    NARCIS (Netherlands)

    Van Buuren, Stef

    2014-01-01

    This article reviews and compares two types of growth charts for tracking human development over age. Both charts assume the existence of a continuous latent variable, but relate to the observed data in different ways. The D-score diagram summarizes developmental indicators into a single aggregate

  5. Proteomic profiling of Plasmodium sporozoite maturation identifies new proteins essential for parasite development and infectivity

    DEFF Research Database (Denmark)

    Lasonder, Edwin; Janse, Chris J; van Gemert, Geert-Jan

    2008-01-01

    Plasmodium falciparum sporozoites that develop and mature inside an Anopheles mosquito initiate a malaria infection in humans. Here we report the first proteomic comparison of different parasite stages from the mosquito -- early and late oocysts containing midgut sporozoites, and the mature...... whose annotation suggest an involvement in sporozoite maturation, motility, infection of the human host and associated metabolic adjustments. Analyses of proteins identified in the P. falciparum sporozoite proteomes by orthologous gene disruption in the rodent malaria parasite, P. berghei, revealed...... three previously uncharacterized Plasmodium proteins that appear to be essential for sporozoite development at distinct points of maturation in the mosquito. This study sheds light on the development and maturation of the malaria parasite in an Anopheles mosquito and also identifies proteins that may...

  6. Employment growth and regional development

    DEFF Research Database (Denmark)

    Eriksson, Rikard; Hansen, Høgni Kalsø; Winther, Lars

    2017-01-01

    This paper explores the potential drivers behind uneven regional development in the context of employment growth in Denmark and Sweden. In particular, we are interested in the roles of urbanization, industrial change and the rise of the new economy as manifested in the growth of the two economies...... in 2002–2007. The aim of this paper is, therefore, to analyse the impact of a number of key industrial sectors on regional employment growth in the two countries. The empirical analysis is based on longitudinal matched employer–employee data retrieved from official registers in each economy from 2002...... economies, we find that, although in general these economies react relatively similarly to changes, embarking on a narrower analysis of the individual sectors reveals marked national differences. This indicates that context matters in the analysis of regional economic dynamics in terms of structure, system...

  7. Using process algebra to develop predator-prey models of within-host parasite dynamics.

    Science.gov (United States)

    McCaig, Chris; Fenton, Andy; Graham, Andrea; Shankland, Carron; Norman, Rachel

    2013-07-21

    As a first approximation of immune-mediated within-host parasite dynamics we can consider the immune response as a predator, with the parasite as its prey. In the ecological literature of predator-prey interactions there are a number of different functional responses used to describe how a predator reproduces in response to consuming prey. Until recently most of the models of the immune system that have taken a predator-prey approach have used simple mass action dynamics to capture the interaction between the immune response and the parasite. More recently Fenton and Perkins (2010) employed three of the most commonly used prey-dependent functional response terms from the ecological literature. In this paper we make use of a technique from computing science, process algebra, to develop mathematical models. The novelty of the process algebra approach is to allow stochastic models of the population (parasite and immune cells) to be developed from rules of individual cell behaviour. By using this approach in which individual cellular behaviour is captured we have derived a ratio-dependent response similar to that seen in the previous models of immune-mediated parasite dynamics, confirming that, whilst this type of term is controversial in ecological predator-prey models, it is appropriate for models of the immune system. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Generation of genetically attenuated blood-stage malaria parasites; characterizing growth and virulence in a rodent model of malaria

    NARCIS (Netherlands)

    Lin, Jingwen

    2013-01-01

    Despite intense efforts over the past 50 years to develop a vaccine, there is currently no licensed malaria vaccine available. The limited success in inducing sufficient protection against malaria with subunit-vaccines has renewed an interest in whole-parasite vaccination strategies. While

  9. Population growth and economic development.

    Science.gov (United States)

    Corbridge, S

    1989-01-01

    The Malthusian and neo-Malthusian approaches to the role of population growth in economic development and resource depletion are briefly outlined. Three arguments are then presented that emphasize demographic determinism, empirical evidence, and cause and effect. The author concludes that non-coercive family planning programs may have a role to play in countries that are unable to reduce inequalities, particularly for the poor and for women.

  10. Patterns of development of trypanosomes and related parasites in insect hosts

    International Nuclear Information System (INIS)

    Molyneux, D.H.

    1980-01-01

    The trypanosome parasites of man and his domestic animals and the closely related Leishmania parasites pathogenic to man have widely different patterns of development in their various vector species. However, certain common features of the development of these parasites are exhibited when they develop in insects. These features include temporary storage in the crop; transformation from mammalian forms to primary multiplicative forms; avoidance of digestion by host enzymes; association with the peritrophic membrane; establishment of infection and, associated with this, attachment and colonization of surfaces; migration to different areas of gut to sites of development; formation of a reservoir of forms to ensure sufficient organisms are available for transformation to forms infective to the vertebrate host; subsequent transmission by bite or by contamination of host surfaces. The different features of development outlined above are discussed in relation to trypanosomes and related parasites. The utilization of different model systems for use in this type of study are discussed in view of difficulties in obtaining adequate numbers of infected flies (e.g. Glossina, or sandflies), and the costs and frequent problems of maintaining such colonies. Recent studies (1) on Glossina-transmitted Salivarian trypanosomes are described which indicate possible behavioural differences between infected and uninfected flies that have a bearing on epidemiology and epizootiology; (2) on the fluid mechanics of the Glossina labrum infected and uninfected with trypanosomes; and (3) on attachment of trypanosomes and Leishmania to insect gut wall surfaces. (author)

  11. Proteomic profiling of Plasmodium sporozoite maturation identifies new proteins essential for parasite development and infectivity.

    NARCIS (Netherlands)

    Lasonder, E.; Janse, C.J.; Gemert, G.J.A. van; Mair, G.R.; Vermunt, A.M.W.; Douradinha, B.G.; Noort, V. van; Huynen, M.A.; Luty, A.J.F.; Kroeze, H.; Khan, S.M.; Sauerwein, R.W.; Waters, A.P.; Mann, M.; Stunnenberg, H.G.

    2008-01-01

    Plasmodium falciparum sporozoites that develop and mature inside an Anopheles mosquito initiate a malaria infection in humans. Here we report the first proteomic comparison of different parasite stages from the mosquito -- early and late oocysts containing midgut sporozoites, and the mature,

  12. Inducible Costimulator Expressing T Cells Promote Parasitic Growth During Blood Stage Plasmodium berghei ANKA Infection

    Directory of Open Access Journals (Sweden)

    Gajendra M. Jogdand

    2018-05-01

    Full Text Available The lethality of blood stage Plasmodium berghei ANKA (PbA infection is associated with the expression of T-bet and production of cytokine IFN-γ. Expression of inducible costimulator (ICOS and its downstream signaling has been shown to play a critical role in the T-bet expression and IFN-γ production. Although earlier studies have examined the role of ICOS in the control of acute blood-stage infection of Plasmodium chabaudi chabaudi AS (a non-lethal model of malaria infection, its significance in the lethal blood-stage of PbA infection remains unclear. Thus, to address the seminal role of ICOS in lethal blood-stage of PbA infection, we treated PbA-infected mice with anti-ICOS antibody and observed that these mice survived longer than their infected counterparts with significantly lower parasitemia. Anti-ICOS treatment notably depleted ICOS expressing CD4+ and CD8+ T cells with a concurrent reduction in plasma IFN-γ, which strongly indicated that ICOS expressing T cells are major IFN-γ producers. Interestingly, we observed that while ICOS expressing CD4+ and CD8+ T cells produced IFN-γ, ICOS−CD8+ T cells were also found to be producers of IFN-γ. However, we report that ICOS+CD8+ T cells were higher producers of IFN-γ than ICOS−CD8+ T cells. Moreover, correlation of ICOS expression with IFN-γ production in ICOS+IFN-γ+ T cell population (CD4+ and CD8+ T cells suggested that ICOS and IFN-γ could positively regulate each other. Further, master transcription factor T-bet importantly involved in regulating IFN-γ production was also found to be expressed by ICOS expressing CD4+ and CD8+ T cells during PbA infection. As noted above with IFN-γ and ICOS, a positive correlation of expression of ICOS with the transcription factor T-bet suggested that both of them could regulate each other. Taken together, our results depicted the importance of ICOS expressing CD4+ and CD8+ T cells in malaria parasite growth and lethality through IFN

  13. Effect of clinically approved HDAC inhibitors on Plasmodium, Leishmania and Schistosoma parasite growth.

    Science.gov (United States)

    Chua, Ming Jang; Arnold, Megan S J; Xu, Weijun; Lancelot, Julien; Lamotte, Suzanne; Späth, Gerald F; Prina, Eric; Pierce, Raymond J; Fairlie, David P; Skinner-Adams, Tina S; Andrews, Katherine T

    2017-04-01

    Malaria, schistosomiasis and leishmaniases are among the most prevalent tropical parasitic diseases and each requires new innovative treatments. Targeting essential parasite pathways, such as those that regulate gene expression and cell cycle progression, is a key strategy for discovering new drug leads. In this study, four clinically approved anti-cancer drugs (Vorinostat, Belinostat, Panobinostat and Romidepsin) that target histone/lysine deacetylase enzymes were examined for in vitro activity against Plasmodium knowlesi, Schistosoma mansoni, Leishmania amazonensis and L. donovani parasites and two for in vivo activity in a mouse malaria model. All four compounds were potent inhibitors of P. knowlesi malaria parasites (IC 50 9-370 nM), with belinostat, panobinostat and vorinostat having 8-45 fold selectivity for the parasite over human neonatal foreskin fibroblast (NFF) or human embryonic kidney (HEK 293) cells, while romidepsin was not selective. Each of the HDAC inhibitor drugs caused hyperacetylation of P. knowlesi histone H4. None of the drugs was active against Leishmania amastigote or promastigote parasites (IC 50  > 20 μM) or S. mansoni schistosomula (IC 50  > 10 μM), however romidepsin inhibited S. mansoni adult worm parings and egg production (IC 50 ∼10 μM). Modest in vivo activity was observed in P. berghei infected mice dosed orally with vorinostat or panobinostat (25 mg/kg twice daily for four days), with a significant reduction in parasitemia observed on days 4-7 and 4-10 after infection (P < 0.05), respectively. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Effect of clinically approved HDAC inhibitors on Plasmodium, Leishmania and Schistosoma parasite growth

    Directory of Open Access Journals (Sweden)

    Ming Jang Chua

    2017-04-01

    Full Text Available Malaria, schistosomiasis and leishmaniases are among the most prevalent tropical parasitic diseases and each requires new innovative treatments. Targeting essential parasite pathways, such as those that regulate gene expression and cell cycle progression, is a key strategy for discovering new drug leads. In this study, four clinically approved anti-cancer drugs (Vorinostat, Belinostat, Panobinostat and Romidepsin that target histone/lysine deacetylase enzymes were examined for in vitro activity against Plasmodium knowlesi, Schistosoma mansoni, Leishmania amazonensis and L. donovani parasites and two for in vivo activity in a mouse malaria model. All four compounds were potent inhibitors of P. knowlesi malaria parasites (IC50 9–370 nM, with belinostat, panobinostat and vorinostat having 8–45 fold selectivity for the parasite over human neonatal foreskin fibroblast (NFF or human embryonic kidney (HEK 293 cells, while romidepsin was not selective. Each of the HDAC inhibitor drugs caused hyperacetylation of P. knowlesi histone H4. None of the drugs was active against Leishmania amastigote or promastigote parasites (IC50 > 20 μM or S. mansoni schistosomula (IC50 > 10 μM, however romidepsin inhibited S. mansoni adult worm parings and egg production (IC50 ∼10 μM. Modest in vivo activity was observed in P. berghei infected mice dosed orally with vorinostat or panobinostat (25 mg/kg twice daily for four days, with a significant reduction in parasitemia observed on days 4–7 and 4–10 after infection (P < 0.05, respectively.

  15. Changes in lipid composition during sexual development of the malaria parasite Plasmodium falciparum.

    Science.gov (United States)

    Tran, Phuong N; Brown, Simon H J; Rug, Melanie; Ridgway, Melanie C; Mitchell, Todd W; Maier, Alexander G

    2016-02-06

    The development of differentiated sexual stages (gametocytes) within human red blood cells is essential for the propagation of the malaria parasite, since only mature gametocytes will survive in the mosquito's midgut. Hence gametocytogenesis is a pre-requisite for transmission of the disease. Physiological changes involved in sexual differentiation are still enigmatic. In particular the lipid metabolism-despite being central to cellular regulation and development-is not well explored. Here the lipid profiles of red blood cells infected with the five different sexual stages of Plasmodium falciparum were analysed by mass spectrometry and compared to those from uninfected and asexual trophozoite infected erythrocytes. Fundamental differences between erythrocytes infected with the different parasite stages were revealed. In mature gametocytes many lipids that decrease in the trophozoite and early gametocyte infected red blood cells are regained. In particular, regulators of membrane fluidity, cholesterol and sphingomyelin, increased significantly during gametocyte maturation. Neutral lipids (serving mainly as caloriometric reserves) increased from 3 % of total lipids in uninfected to 27 % in stage V gametocyte infected red blood cells. The major membrane lipid class (phospholipids) decreased during gametocyte development. The lipid profiles of infected erythrocytes are characteristic for the particular parasite life cycle and maturity stages of gametocytes. The obtained lipid profiles are crucial in revealing the lipid metabolism of malaria parasites and identifying targets to interfere with this deadly disease.

  16. Heritable Variation in Quinone-Induced Haustorium Development in the Parasitic Plant Triphysaria1

    Science.gov (United States)

    Jamison, Denneal S.; Yoder, John I.

    2001-01-01

    We are using the facultative hemiparasite, Triphysaria, as a model for studying host-parasite signaling in the Scrophulariaceae. Parasitic members of this family form subterranean connections, or haustoria, on neighboring host roots to access host water and nutrients. These parasitic organs develop in response to haustorial-inducing factors contained in host root exudates. A well-characterized inducing factor, 2, 6-dimethoxy-p-benzoquinone (DMBQ), can be used to trigger in vitro haustorium formation in the roots of Triphysaria. We have assayed three species, Triphysaria eriantha (Benth.) Chuang and Heckard, Triphysaria pusilla (Benth.) Chuang and Heckard, and Triphysaria versicolor Fischer and C. Meyer, for haustorium development in response to DMBQ. There were significant differences between the species in their ability to recognize and respond to this quinone. Ninety percent of T. versicolor individuals responded, whereas only 40% of T. pusilla and less than 10% of T. eriantha formed haustoria. Within field collections of self-pollinating T. pusilla, differential responsiveness to DMBQ was seen in distinct maternal families. Assaying haustorium development in subsequent generations of self-pollinated T. pusilla showed that DMBQ responsiveness was heritable. Reciprocal crosses between T. eriantha and T. versicolor demonstrated that DMBQ responsiveness was influenced by maternal factors. These results demonstrate heritable, natural variation in the recognition of a haustorial-inducing factor by a parasitic member of the Scrophulariaceae. PMID:11299366

  17. Exo-erythrocytic development of avian malaria and related haemosporidian parasites.

    Science.gov (United States)

    Valkiūnas, Gediminas; Iezhova, Tatjana A

    2017-03-03

    Avian malaria parasites (Plasmodium spp.) and related haemosporidians (Haemosporida) are responsible for diseases which can be severe and even lethal in avian hosts. These parasites cause not only blood pathology, but also damage various organs due to extensive exo-erythrocytic development all over the body, which is not the case during Plasmodium infections in mammals. However, exo-erythrocytic development (tissue merogony or schizogony) remains the most poorly investigated part of life cycle in all groups of wildlife haemosporidian parasites. In spite of remarkable progress in studies of genetic diversity, ecology and evolutionary biology of avian haemosporidians during the past 20 years, there is not much progress in understanding patterns of exo-erythrocytic development in these parasites. The purpose of this review is to overview the main information on exo-erythrocytic development of avian Plasmodium species and related haemosporidian parasites as a baseline for assisting academic and veterinary medicine researchers in morphological identification of these parasites using tissue stages, and to define future research priorities in this field of avian malariology. The data were considered from peer-reviewed articles and histological material that was accessed in zoological collections in museums of Australia, Europe and the USA. Articles describing tissue stages of avian haemosporidians were included from 1908 to the present. Histological preparations of various organs infected with the exo-erythrocytic stages of different haemosporidian parasites were examined. In all, 229 published articles were included in this review. Exo-erythrocytic stages of avian Plasmodium, Fallisia, Haemoproteus, Leucocytozoon, and Akiba species were analysed, compared and illustrated. Morphological characters of tissue stages that can be used for diagnostic purposes were specified. Recent molecular studies combined with histological research show that avian haemosporidians are more

  18. Development of fluorescent Plasmodium falciparum for in vitro growth inhibition assays

    Directory of Open Access Journals (Sweden)

    Crabb Brendan S

    2010-06-01

    Full Text Available Abstract Background Plasmodium falciparum in vitro growth inhibition assays are widely used to evaluate and quantify the functional activity of acquired and vaccine-induced antibodies and the anti-malarial activity of known drugs and novel compounds. However, several constraints have limited the use of these assays in large-scale population studies, vaccine trials and compound screening for drug discovery and development. Methods The D10 P. falciparum line was transfected to express green fluorescent protein (GFP. In vitro growth inhibition assays were performed over one or two cycles of P. falciparum asexual replication using inhibitory polyclonal antibodies raised in rabbits, an inhibitory monoclonal antibody, human serum samples, and anti-malarials. Parasitaemia was evaluated by microscopy and flow cytometry. Results Transfected parasites expressed GFP throughout all asexual stages and were clearly detectable by flow cytometry and fluorescence microscopy. Measurement of parasite growth inhibition was the same when determined by detection of GFP fluorescence or staining with ethidium bromide. There was no difference in the inhibitory activity of samples when tested against the transfected parasites compared to the parental line. The level of fluorescence of GFP-expressing parasites increased throughout the course of asexual development. Among ring-stages, GFP-fluorescent parasites were readily separated from uninfected erythrocytes by flow cytometry, whereas this was less clear using ethidium bromide staining. Inhibition by serum and antibody samples was consistently higher when tested over two cycles of growth compared to one, and when using a 1 in 10 sample dilution compared to 1 in 20, but there was no difference detected when using a different starting parasitaemia to set-up growth assays. Flow cytometry based measurements of parasitaemia proved more reproducible than microscopy counts. Conclusions Flow cytometry based assays using GFP

  19. Predators and patterns of within-host growth can mediate both among-host competition and evolution of transmission potential of parasites.

    Science.gov (United States)

    Auld, Stuart K J R; Hall, Spencer R; Housley Ochs, Jessica; Sebastian, Mathew; Duffy, Meghan A

    2014-08-01

    Parasite prevalence shows tremendous spatiotemporal variation. Theory indicates that this variation might stem from life-history characteristics of parasites and key ecological factors. Here, we illustrate how the interaction of an important predator and the schedule of transmission potential of two parasites can explain parasite abundance. A field survey showed that a noncastrating fungus (Metschnikowia bicuspidata) commonly infected a dominant zooplankton host (Daphnia dentifera), while a castrating bacterial parasite (Pasteuria ramosa) was rare. This result seemed surprising given that the bacterium produces many more infectious propagules (spores) than the fungus upon host death. The fungus's dominance can be explained by the schedule of within-host growth of parasites (i.e., how transmission potential changes over the course of infection) and the release of spores from "sloppy" predators (Chaoborus spp., who consume Daphnia prey whole and then later regurgitate the carapace and parasite spores). In essence, sloppy predators create a niche that the faster-schedule fungus currently occupies. However, a selection experiment showed that the slower-schedule bacterium can evolve into this faster-schedule, predator-mediated niche (but pays a cost in maximal spore yield to do so). Hence, our study shows how parasite life history can interact with predation to strongly influence the ecology, epidemiology, and evolution of infectious disease.

  20. Growth charts of human development.

    Science.gov (United States)

    van Buuren, Stef

    2014-08-01

    This article reviews and compares two types of growth charts for tracking human development over age. Both charts assume the existence of a continuous latent variable, but relate to the observed data in different ways. The D-score diagram summarizes developmental indicators into a single aggregate score measuring global development. The relations between the indicators should be consistent with the Rasch model. If true, the D-score is a measure with interval scale properties, and allows for the calculation of meaningful differences both within and across age. The stage line diagram describes the natural development of ordinal indicators. The method models the transition probabilities between successive stages of the indicator as smoothly varying functions of age. The location of each stage is quantified by the mid-P-value. Both types of diagrams assist in identifying early and delayed development, as well as finding differences in tempo. The relevant techniques are illustrated to track global development during infancy and early childhood (0-2 years) and Tanner pubertal stages (8-21 years). New reference values for both applications are provided. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  1. Disrupting Mosquito Reproduction and Parasite Development for Malaria Control.

    Directory of Open Access Journals (Sweden)

    Lauren M Childs

    2016-12-01

    Full Text Available The control of mosquito populations with insecticide treated bed nets and indoor residual sprays remains the cornerstone of malaria reduction and elimination programs. In light of widespread insecticide resistance in mosquitoes, however, alternative strategies for reducing transmission by the mosquito vector are urgently needed, including the identification of safe compounds that affect vectorial capacity via mechanisms that differ from fast-acting insecticides. Here, we show that compounds targeting steroid hormone signaling disrupt multiple biological processes that are key to the ability of mosquitoes to transmit malaria. When an agonist of the steroid hormone 20-hydroxyecdysone (20E is applied to Anopheles gambiae females, which are the dominant malaria mosquito vector in Sub Saharan Africa, it substantially shortens lifespan, prevents insemination and egg production, and significantly blocks Plasmodium falciparum development, three components that are crucial to malaria transmission. Modeling the impact of these effects on Anopheles population dynamics and Plasmodium transmission predicts that disrupting steroid hormone signaling using 20E agonists would affect malaria transmission to a similar extent as insecticides. Manipulating 20E pathways therefore provides a powerful new approach to tackle malaria transmission by the mosquito vector, particularly in areas affected by the spread of insecticide resistance.

  2. Modification of host erythrocyte membranes by trypsin and chymotrypsin treatments and effects on the in vitro growth of bovine and equine Babesia parasites.

    Science.gov (United States)

    Okamura, Masashi; Yokoyama, Naoaki; Takabatake, Noriyuki; Okubo, Kazuhiro; Ikehara, Yuzuru; Igarashi, Ikuo

    2007-02-01

    In the present study, we investigated the effects of protease pretreatments of host erythrocytes (RBC) on the in vitro growth of bovine Babesia parasites (Babesia bovis and B. bigemina) and equine Babesia parasites (B. equi and B. caballi). The selected proteases, trypsin and chymotrypsin, clearly modified several membrane proteins of both bovine and equine RBC, as demonstrated by SDS-PAGE analysis; however, the protease treatments also modified the sialic acid content exclusively in bovine RBC, as demonstrated by lectin blot analysis. An in vitro growth assay using the protease-treated RBC showed that the trypsin-treated bovine RBC, but not the chymotrypsin-treated ones, significantly reduced the growth of B. bovis and B. bigemina as compared to the control. In contrast, the growth of B. equi and B. caballi was not affected by any of these proteases. Thus, the bovine, but not the equine, Babesia parasites require the trypsin-sensitive membrane (sialoglyco) proteins to infect the RBC.

  3. Survival, reproduction, growth, and parasite resistance of aquatic organisms exposed on-site to wastewater treated by advanced treatment processes.

    Science.gov (United States)

    Schlüter-Vorberg, Lisa; Knopp, Gregor; Cornel, Peter; Ternes, Thomas; Coors, Anja

    2017-05-01

    Advanced wastewater treatment technologies are generally known to be an effective tool for reducing micropollutant discharge into the aquatic environment. Nevertheless, some processes such as ozonation result in stable transformation products with often unknown toxicity. In the present study, whole effluents originating from nine different steps of advanced treatment combinations were compared for their aquatic toxicity. Assessed endpoints were survival, growth and reproduction of Lumbriculus variegatus, Daphnia magna and Lemna minor chronically exposed in on-site flow-through tests based on standard guidelines. The treatment combinations were activated sludge treatment followed by ozonation with subsequent filtration by granular activated carbon or biofilters and membrane bioreactor treatment of raw wastewater followed by ozonation. Additionally, the impact of treated wastewater on the immune response of invertebrates was investigated by challenging D. magna with a bacterial endoparasite. Conventionally treated wastewater reduced reproduction of L. variegatus by up to 46%, but did not affect D. magna and L. minor with regard to survival, growth, reproduction and parasite resistance. Instead, parasite susceptibility was significantly reduced in D. magna exposed to conventionally treated as well as ozonated wastewater in comparison to D. magna exposed to the medium control. None of the three test organisms provided clear evidence that wastewater ozonation leads to increased aquatic toxicity. Rather than to the presence of toxic transformation products, the affected performance of L. variegatus could be linked to elevated concentrations of ammonium and nitrite that likely resulted from treatment failures. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. An Ancient Protein Phosphatase, SHLP1, Is Critical to Microneme Development in Plasmodium Ookinetes and Parasite Transmission

    Directory of Open Access Journals (Sweden)

    Eva-Maria Patzewitz

    2013-03-01

    Full Text Available Signaling pathways controlled by reversible protein phosphorylation (catalyzed by kinases and phosphatases in the malaria parasite Plasmodium are of great interest, for both increased understanding of parasite biology and identification of novel drug targets. Here, we report a functional analysis in Plasmodium of an ancient bacterial Shewanella-like protein phosphatase (SHLP1 found only in bacteria, fungi, protists, and plants. SHLP1 is abundant in asexual blood stages and expressed at all stages of the parasite life cycle. shlp1 deletion results in a reduction in ookinete (zygote development, microneme formation, and complete ablation of oocyst formation, thereby blocking parasite transmission. This defect is carried by the female gamete and can be rescued by direct injection of mutant ookinetes into the mosquito hemocoel, where oocysts develop. This study emphasizes the varied functions of SHLP1 in Plasmodium ookinete biology and suggests that it could be a novel drug target for blocking parasite transmission.

  5. Cellulose filtration of blood from malaria patients for improving ex vivo growth of Plasmodium falciparum parasites

    DEFF Research Database (Denmark)

    Mkumbaye, Sixbert I; Minja, Daniel T R; Jespersen, Jakob S

    2017-01-01

    faster than non-filtered parasites seemingly due to a higher development ratio of ring stage parasites progressing into the late stages. Cellulose filtration had no apparent effect on clonality or var gene expression; however, evident differences were observed after only 4 days of culture in both...

  6. Brood parasite and host eggshells undergo similar levels of decalcification during embryonic development

    Czech Academy of Sciences Publication Activity Database

    Igic, B.; Hauber, M. E.; Moskát, C.; Grim, T.; Shawkey, M. D.; Procházka, Petr; Honza, Marcel

    2017-01-01

    Roč. 301, č. 3 (2017), s. 165-173 ISSN 0952-8369 R&D Projects: GA ČR(CZ) GAP506/12/2404 Institutional support: RVO:68081766 Keywords : Acrocephalus arundinaceus * brood parasitism * Cuculus canorus * decalcification * eggshell thickness * embryonic development * common cuckoo * scanning electron microscopy Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 2.186, year: 2016

  7. A Trematode Parasite Derived Growth Factor Binds and Exerts Influences on Host Immune Functions via Host Cytokine Receptor Complexes.

    Directory of Open Access Journals (Sweden)

    Azad A Sulaiman

    2016-11-01

    Full Text Available The trematode Fasciola hepatica is responsible for chronic zoonotic infection globally. Despite causing a potent T-helper 2 response, it is believed that potent immunomodulation is responsible for rendering this host reactive non-protective host response thereby allowing the parasite to remain long-lived. We have previously identified a growth factor, FhTLM, belonging to the TGF superfamily can have developmental effects on the parasite. Herein we demonstrate that FhTLM can exert influence over host immune functions in a host receptor specific fashion. FhTLM can bind to receptor members of the Transforming Growth Factor (TGF superfamily, with a greater affinity for TGF-β RII. Upon ligation FhTLM initiates the Smad2/3 pathway resulting in phenotypic changes in both fibroblasts and macrophages. The formation of fibroblast CFUs is reduced when cells are cultured with FhTLM, as a result of TGF-β RI kinase activity. In parallel the wound closure response of fibroblasts is also delayed in the presence of FhTLM. When stimulated with FhTLM blood monocyte derived macrophages adopt an alternative or regulatory phenotype. They express high levels interleukin (IL-10 and arginase-1 while displaying low levels of IL-12 and nitric oxide. Moreover they also undergo significant upregulation of the inhibitory receptor PD-L1 and the mannose receptor. Use of RNAi demonstrates that this effect is dependent on TGF-β RII and mRNA knock-down leads to a loss of IL-10 and PD-L1. Finally, we demonstrate that FhTLM aids newly excysted juveniles (NEJs in their evasion of antibody-dependent cell cytotoxicity (ADCC by reducing the NO response of macrophages-again dependent on TGF-β RI kinase. FhTLM displays restricted expression to the F. hepatica gut resident NEJ stages. The altered fibroblast responses would suggest a role for dampened tissue repair responses in facilitating parasite migration. Furthermore, the adoption of a regulatory macrophage phenotype would allow

  8. Transcriptome analysis in oak uncovers a strong impact of endogenous rhythmic growth on the interaction with plant-parasitic nematodes.

    Science.gov (United States)

    Maboreke, Hazel R; Feldhahn, Lasse; Bönn, Markus; Tarkka, Mika T; Buscot, Francois; Herrmann, Sylvie; Menzel, Ralph; Ruess, Liliane

    2016-08-12

    Pedunculate oak (Quercus robur L.), an important forest tree in temperate ecosystems, displays an endogenous rhythmic growth pattern, characterized by alternating shoot and root growth flushes paralleled by oscillations in carbon allocation to below- and aboveground tissues. However, these common plant traits so far have largely been neglected as a determining factor for the outcome of plant biotic interactions. This study investigates the response of oak to migratory root-parasitic nematodes in relation to rhythmic growth, and how this plant-nematode interaction is modulated by an ectomycorrhizal symbiont. Oaks roots were inoculated with the nematode Pratylenchus penetrans solely and in combination with the fungus Piloderma croceum, and the systemic impact on oak plants was assessed by RNA transcriptomic profiles in leaves. The response of oaks to the plant-parasitic nematode was strongest during shoot flush, with a 16-fold increase in the number of differentially expressed genes as compared to root flush. Multi-layered defence mechanisms were induced at shoot flush, comprising upregulation of reactive oxygen species formation, hormone signalling (e.g. jasmonic acid synthesis), and proteins involved in the shikimate pathway. In contrast during root flush production of glycerolipids involved in signalling cascades was repressed, suggesting that P. penetrans actively suppressed host defence. With the presence of the mycorrhizal symbiont, the gene expression pattern was vice versa with a distinctly stronger effect of P. penetrans at root flush, including attenuated defence, cell and carbon metabolism, likely a response to the enhanced carbon sink strength in roots induced by the presence of both, nematode and fungus. Meanwhile at shoot flush, when nutrients are retained in aboveground tissue, oak defence reactions, such as altered photosynthesis and sugar pathways, diminished. The results highlight that gene response patterns of plants to biotic interactions, both

  9. A novel genetic technique in Plasmodium berghei allows liver stage analysis of genes required for mosquito stage development and demonstrates that de novo heme synthesis is essential for liver stage development in the malaria parasite.

    Directory of Open Access Journals (Sweden)

    Upeksha L Rathnapala

    2017-06-01

    Full Text Available The combination of drug resistance, lack of an effective vaccine, and ongoing conflict and poverty means that malaria remains a major global health crisis. Understanding metabolic pathways at all parasite life stages is important in prioritising and targeting novel anti-parasitic compounds. The unusual heme synthesis pathway of the rodent malaria parasite, Plasmodium berghei, requires eight enzymes distributed across the mitochondrion, apicoplast and cytoplasm. Deletion of the ferrochelatase (FC gene, the final enzyme in the pathway, confirms that heme synthesis is not essential in the red blood cell stages of the life cycle but is required to complete oocyst development in mosquitoes. The lethality of FC deletions in the mosquito stage makes it difficult to study the impact of these mutations in the subsequent liver stage. To overcome this, we combined locus-specific fluorophore expression with a genetic complementation approach to generate viable, heterozygous oocysts able to produce a mix of FC expressing and FC deficient sporozoites. These sporozoites show normal motility and can invade liver cells, where FC deficient parasites can be distinguished by fluorescence and phenotyped. Parasites lacking FC exhibit a severe growth defect within liver cells, with development failure detectable in the early to mid stages of liver development in vitro. FC deficient parasites could not complete liver stage development in vitro nor infect naïve mice, confirming liver stage arrest. These results validate the heme pathway as a potential target for prophylactic drugs targeting liver stage parasites. In addition, we demonstrate that our simple genetic approach can extend the phenotyping window beyond the insect stages, opening considerable scope for straightforward reverse genetic analysis of genes that are dispensable in blood stages but essential for completing mosquito development.

  10. A novel genetic technique in Plasmodium berghei allows liver stage analysis of genes required for mosquito stage development and demonstrates that de novo heme synthesis is essential for liver stage development in the malaria parasite.

    Science.gov (United States)

    Rathnapala, Upeksha L; Goodman, Christopher D; McFadden, Geoffrey I

    2017-06-01

    The combination of drug resistance, lack of an effective vaccine, and ongoing conflict and poverty means that malaria remains a major global health crisis. Understanding metabolic pathways at all parasite life stages is important in prioritising and targeting novel anti-parasitic compounds. The unusual heme synthesis pathway of the rodent malaria parasite, Plasmodium berghei, requires eight enzymes distributed across the mitochondrion, apicoplast and cytoplasm. Deletion of the ferrochelatase (FC) gene, the final enzyme in the pathway, confirms that heme synthesis is not essential in the red blood cell stages of the life cycle but is required to complete oocyst development in mosquitoes. The lethality of FC deletions in the mosquito stage makes it difficult to study the impact of these mutations in the subsequent liver stage. To overcome this, we combined locus-specific fluorophore expression with a genetic complementation approach to generate viable, heterozygous oocysts able to produce a mix of FC expressing and FC deficient sporozoites. These sporozoites show normal motility and can invade liver cells, where FC deficient parasites can be distinguished by fluorescence and phenotyped. Parasites lacking FC exhibit a severe growth defect within liver cells, with development failure detectable in the early to mid stages of liver development in vitro. FC deficient parasites could not complete liver stage development in vitro nor infect naïve mice, confirming liver stage arrest. These results validate the heme pathway as a potential target for prophylactic drugs targeting liver stage parasites. In addition, we demonstrate that our simple genetic approach can extend the phenotyping window beyond the insect stages, opening considerable scope for straightforward reverse genetic analysis of genes that are dispensable in blood stages but essential for completing mosquito development.

  11. The Fatty Acid Biosynthesis Enzyme FabI Plays a Key Role In the Development of Liver Stage Malarial Parasites

    Science.gov (United States)

    Yu, Min; Santha Kumar, T. R.; Nkrumah, Louis J.; Coppi, Alida; Retzlaff, Silke; Li, Celeste D.; Kelly, Brendan J.; Moura, Pedro A.; Lakshmanan, Viswanathan; Freundlich, Joel S.; Valderramos, Juan-Carlos; Vilcheze, Catherine; Siedner, Mark; Tsai, Jennifer H.-C.; Falkard, Brie; Sidhu, Amar bir Singh; Purcell, Lisa A.; Gratraud, Paul; Kremer, Laurent; Waters, Andy P.; Schiehser, Guy; Jacobus, David P.; Janse, Chris J.; Ager, Arba; Jacobs, William R.; Sacchettini, James C.; Heussler, Volker; Sinnis, Photini; Fidock, David A.

    2008-01-01

    SUMMARY Fatty acid biosynthesis has been viewed as an important biological function of and therapeutic target for Plasmodium falciparum asexual blood stage infection. This apicoplast-resident type II pathway, distinct from the mammalian type I process, includes FabI. Here, we report synthetic chemistry and transfection studies concluding that Plasmodium FabI is not the target of the antimalarial activity of the bacterial FabI inhibitor triclosan. Disruption of fabI in P. falciparum or the rodent parasite P. berghei does not impede blood stage growth. In contrast, mosquito-derived fabI-deficient P. berghei sporozoites are markedly less infective for mice and typically fail to complete liver stage development in vitro. This is characterized by an inability to form intra-hepatic merosomes that normally initiate blood stage infections. These data illuminate key differences between liver and blood stage parasites in their requirements for host versus de novo synthesized fatty acids, and create new prospects for stage-specific antimalarial interventions. PMID:19064257

  12. CT arteriography via the right inferior phrenic artery developed parasitic perfusion into the liver

    International Nuclear Information System (INIS)

    Inaba, Yoshitaka; Arai, Yasuaki; Sueyoshi, Satoshi; Yamagami, Takuji; Aramaki, Takeshi; Yamaura, Hidekazu; Matsueda, Kiyoshi; Sasaki, Fumio; Takeuchi, Yoshihito.

    1998-01-01

    The distribution of arterial blood flow via the right inferior phrenic artery (rt-IPA) developing parasitic perfusion into the liver was evaluated by CT arteriography (CTA) in 50 cases with hepatic tumors. In all cases, CTA via rt-IPA showed hyperperfusion area including hepatic tumors in the posterior segment and the caudate lobe of the liver, and adding the left hepatic lobe in cases with hepatic arterial occlusion. In 82% of 33 cases obtained both CTA via rt-IPA and CTA via hepatic artery, the hyperperfusion area on CTA via rt-IPA exactly corresponded to perfusion defect area on CTA via hepatic artery. CTA was much useful for understanding hemodynamics in cases with parasitic perfusion into the liver and it could make transcatheter arterial therapy more effective. (author)

  13. CT arteriography via the right inferior phrenic artery developed parasitic perfusion into the liver

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Yoshitaka; Arai, Yasuaki; Sueyoshi, Satoshi; Yamagami, Takuji; Aramaki, Takeshi; Yamaura, Hidekazu; Matsueda, Kiyoshi; Sasaki, Fumio [Aichi Cancer Center, Nagoya (Japan); Takeuchi, Yoshihito

    1998-02-01

    The distribution of arterial blood flow via the right inferior phrenic artery (rt-IPA) developing parasitic perfusion into the liver was evaluated by CT arteriography (CTA) in 50 cases with hepatic tumors. In all cases, CTA via rt-IPA showed hyperperfusion area including hepatic tumors in the posterior segment and the caudate lobe of the liver, and adding the left hepatic lobe in cases with hepatic arterial occlusion. In 82% of 33 cases obtained both CTA via rt-IPA and CTA via hepatic artery, the hyperperfusion area on CTA via rt-IPA exactly corresponded to perfusion defect area on CTA via hepatic artery. CTA was much useful for understanding hemodynamics in cases with parasitic perfusion into the liver and it could make transcatheter arterial therapy more effective. (author)

  14. On the importance of targeting parasite stem cells in anti-echinococcosis drug development

    Directory of Open Access Journals (Sweden)

    Brehm Klaus

    2014-01-01

    Full Text Available The life-threatening diseases alveolar and cystic echinococcoses are caused by larvae of the tapeworms Echinococcus multilocularis and E. granulosus, respectively. In both cases, intermediate hosts, such as humans, are infected by oral uptake of oncosphere larvae, followed by asexual multiplication and almost unrestricted growth of the metacestode within host organs. Besides surgery, echinococcosis treatment relies on benzimidazole-based chemotherapy, directed against parasite beta-tubulin. However, since beta-tubulins are highly similar between cestodes and humans, benzimidazoles can only be applied at parasitostatic doses and are associated with adverse side effects. Mostly aiming at identifying alternative drug targets, the nuclear genome sequences of E. multilocularis and E. granulosus have recently been characterized, revealing a large number of druggable targets that are expressed by the metacestode. Furthermore, recent cell biological investigations have demonstrated that E. multilocularis employs pluripotent stem cells, called germinative cells, which are the only parasite cells capable of proliferation and which give rise to all differentiated cells. Hence, the germinative cells are the crucial cell type mediating proliferation of E. multilocularis, and most likely also E. granulosus, within host organs and should also be responsible for parasite recurrence upon discontinuation of chemotherapy. Interestingly, recent investigations have also indicated that germinative cells might be less sensitive to chemotherapy because they express a beta-tubulin isoform with limited affinity to benzimidazoles. In this article, we briefly review the recent findings concerning Echinococcus genomics and stem cell research and propose that future research into anti-echinococcosis drugs should also focus on the parasite’s stem cell population.

  15. Immunity to parasitic infection

    National Research Council Canada - National Science Library

    Lamb, Tracey J

    2012-01-01

    ... may be manipulated to develop therapeutic interventions against parasitic infection. For easy reference, the most commonly studied parasites are examined in individual chapters written by investigators at the forefront of their field...

  16. Immunity to parasitic infection

    National Research Council Canada - National Science Library

    Lamb, Tracey J

    2012-01-01

    .... Often endemic in developing countries many parasitic diseases are neglected in terms of research funding and much remains to be understood about parasites and the interactions they have with the immune system...

  17. An interplay between 2 signaling pathways: Melatonin-cAMP and IP{sub 3}–Ca{sup 2+} signaling pathways control intraerythrocytic development of the malaria parasite Plasmodium falciparum

    Energy Technology Data Exchange (ETDEWEB)

    Furuyama, Wakako [National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555 (Japan); Enomoto, Masahiro [Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7 Toronto, Ontario (Canada); Mossaad, Ehab [National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555 (Japan); Kawai, Satoru [Laboratory of Tropical Medicine and Parasitology, Dokkyo Medical University, Mibu, Tochigi 321-0293 (Japan); Mikoshiba, Katsuhiko [Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Wako, Saitama 351-0198 (Japan); Kawazu, Shin-ichiro, E-mail: skawazu@obihiro.ac.jp [National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555 (Japan)

    2014-03-28

    Highlights: • A melatonin receptor antagonist blocked Ca{sup 2+} oscillation in P. falciparum and inhibited parasite growth. • P. falciparum development is controlled by Ca{sup 2+}- and cAMP-signaling pathways. • The cAMP-signaling pathway at ring form and late trophozoite stages governs parasite growth of P. falciparum. - Abstract: Plasmodium falciparum spends most of its asexual life cycle within human erythrocytes, where proliferation and maturation occur. Development into the mature forms of P. falciparum causes severe symptoms due to its distinctive sequestration capability. However, the physiological roles and the molecular mechanisms of signaling pathways that govern development are poorly understood. Our previous study showed that P. falciparum exhibits stage-specific spontaneous Calcium (Ca{sup 2+}) oscillations in ring and early trophozoites, and the latter was essential for parasite development. In this study, we show that luzindole (LZ), a selective melatonin receptor antagonist, inhibits parasite growth. Analyses of development and morphology of LZ-treated P. falciparum revealed that LZ severely disrupted intraerythrocytic maturation, resulting in parasite death. When LZ was added at ring stage, the parasite could not undergo further development, whereas LZ added at the trophozoite stage inhibited development from early into late schizonts. Live-cell Ca{sup 2+} imaging showed that LZ treatment completely abolished Ca{sup 2+} oscillation in the ring forms while having little effect on early trophozoites. Further, the melatonin-induced cAMP increase observed at ring and late trophozoite stage was attenuated by LZ treatment. These suggest that a complex interplay between IP{sub 3}–Ca{sup 2+} and cAMP signaling pathways is involved in intraerythrocytic development of P. falciparum.

  18. Mitosis in the Human Malaria Parasite Plasmodium falciparum ▿

    OpenAIRE

    Gerald, Noel; Mahajan, Babita; Kumar, Sanjai

    2011-01-01

    Malaria is caused by intraerythrocytic protozoan parasites belonging to Plasmodium spp. (phylum Apicomplexa) that produce significant morbidity and mortality, mostly in developing countries. Plasmodium parasites have a complex life cycle that includes multiple stages in anopheline mosquito vectors and vertebrate hosts. During the life cycle, the parasites undergo several cycles of extreme population growth within a brief span, and this is critical for their continued transmission and a contri...

  19. Forward genetic screening identifies a small molecule that blocks Toxoplasma gondii growth by inhibiting both host- and parasite-encoded kinases.

    Directory of Open Access Journals (Sweden)

    Kevin M Brown

    2014-06-01

    Full Text Available The simultaneous targeting of host and pathogen processes represents an untapped approach for the treatment of intracellular infections. Hypoxia-inducible factor-1 (HIF-1 is a host cell transcription factor that is activated by and required for the growth of the intracellular protozoan parasite Toxoplasma gondii at physiological oxygen levels. Parasite activation of HIF-1 is blocked by inhibiting the family of closely related Activin-Like Kinase (ALK host cell receptors ALK4, ALK5, and ALK7, which was determined in part by use of an ALK4,5,7 inhibitor named SB505124. Besides inhibiting HIF-1 activation, SB505124 also potently blocks parasite replication under normoxic conditions. To determine whether SB505124 inhibition of parasite growth was exclusively due to inhibition of ALK4,5,7 or because the drug inhibited a second kinase, SB505124-resistant parasites were isolated by chemical mutagenesis. Whole-genome sequencing of these mutants revealed mutations in the Toxoplasma MAP kinase, TgMAPK1. Allelic replacement of mutant TgMAPK1 alleles into wild-type parasites was sufficient to confer SB505124 resistance. SB505124 independently impacts TgMAPK1 and ALK4,5,7 signaling since drug resistant parasites could not activate HIF-1 in the presence of SB505124 or grow in HIF-1 deficient cells. In addition, TgMAPK1 kinase activity is inhibited by SB505124. Finally, mice treated with SB505124 had significantly lower tissue burdens following Toxoplasma infection. These data therefore identify SB505124 as a novel small molecule inhibitor that acts by inhibiting two distinct targets, host HIF-1 and TgMAPK1.

  20. Development of lymphatic filarial parasite Wuchereria bancrofti (Spirurida: Onchocercidae) in mosquito species (Diptera: Culicidae) fed artificially on microfilaremic blood.

    Science.gov (United States)

    Paily, K P; Hoti, S L; Balaraman, K

    2006-11-01

    The efficiency of laboratory colonies of mosquitoes such as Anopheles stephensi Liston, Aedes aegypti (L.) Liverpool strain, Ae. aegypti wild type, Aedes albopictus (Skuse), Culex tritaeniorhynchus Giles, Culex sitiens Wiedemann, and Armigeres subalbatus Coquillett in supporting the development of Wuchereria bancrofti (Cobbold) (Spirurida: Onchocercidae) microfilariae to infective larvae was investigated. The mosquitoes were fed on heparinized microfilaremic human blood by using a membrane-feeding unit with Parafilm as membrane. The rate of infection, parasite development, and parasite burden were compared with that in the known vector mosquito Culex quinquefasciatus Say. Cx. quinquefasciatus showed the highest percentage of infection, followed by Ae. aegypti Liverpool strain and An. stephensi. The rate of development of the parasite was more or less similar in all the three species, and infective larvae were found on day 13. When the larvae were harvested on day 17, Cx. quinquefasciatus yielded the highest numbers, followed by Ae. aegypti Liverpool strain and An. stephensi. The percentage of infection was low, and the development was slow in Cx. tritaeniorhynchus compared with the other susceptible species. The parasite developed to second-stage larvae only by day 22 and to infective larvae by day 28. When 2-wk-old Cx. tritaeniorhynchus were fed on microfilaremic blood, they could develop the parasite to infective larvae by day 13 postfeeding. All other species of mosquitoes tested were found to be refractory to parasite development. It is shown that Cx. quinquefasciatus is the most suitable mosquito host for the production of infective larvae. However, Ae. aegypti Liverpool strain, which is commonly used for Brugia malayi filarial parasite, also can be used for generation of W. bancrofti infective larvae to circumvent the problem of maintaining two mosquito species.

  1. Financial development, uncertainty and economic growth

    NARCIS (Netherlands)

    Lensink, B.W.

    By performing a cross-country growth regression for the 1970-1998 period this paper finds evidence for the fact that the impact of policy uncertainty on economic growth depends on the development of the financial sector. It appears that a higher level of financial development partly mitigates the

  2. Financial Development, Environmental Quality and Economic Growth

    Directory of Open Access Journals (Sweden)

    Shushu Li

    2015-07-01

    Full Text Available In this study, the relationships between financial development, environmental quality and economic growth are studied based on data from 102 countries over the period 1980–2010 using the generalized method of moments (GMM estimation. The econometric results show the following three basic conclusions: First, both financial development and environmental quality have a significant impact on economic growth and should be included in the production function of the economic growth model as important variables. Second, there is a significant and robust “inverted U-shaped” relationship between financial development and economic growth; with the improvement of the level of financial development, economic growth would first increase and then decrease, which is consistent with the results of previous studies. Third, there is also a significant and robust “inverted U-shaped” relationship between economic growth and carbon emissions, indicating that there exists a “critical point” at which achieving economic growth comes at the expense of environmental quality, and after passing the critical point, the deterioration of environmental quality will lead to a significant slowdown in economic growth. In addition, the econometric analysis in this paper also shows that there was a mutually promoting and strengthening relationship between financial development and environmental quality. Specifically, the degree of financial development can further strengthen the promoting effect of environmental quality on economic growth; meanwhile, an improvement in environmental quality can also strengthen the promoting effect of financial development on economic growth. Financial development and environmental quality could influence economic growth through strengthening the marginal product effects of capital and labor, which further indicates the that both financial and environmental factors play an important role in modern economic development.

  3. Seasonal patterns in growth, blood consumption, and effects on hosts by parasitic-phase sea lampreys in the Great Lakes: an individual-based model approach

    Science.gov (United States)

    Madenjian, Charles P.; Cochran, Philip A.; Bergstedt, Roger A.

    2003-01-01

    An individual-based model (IBM) was developed for sea lamprey (Petromyzon marinus) populations in the Laurentian Great Lakes. The IBM was then calibrated to observed growth, by season, for sea lampreys in northern Lake Huron under two different water temperature regimes: a regime experienced by Seneca-strain lake trout (Salvelinus namaycush) and a regime experienced by Marquettestrain lake trout. Modeling results indicated that seasonal blood consumption under the Seneca regime was very similar to that under the Marquette regime. Simulated mortality of lake trout directly due to blood removal by sea lampreys occurred at nearly twice the rate during August and September under the Marquette regime than under the Seneca regime. However, cumulative sea lamprey-induced mortality on lake trout over the entire duration of the sea lamprey's parasitic phase was only 7% higher for the Marquette regime compared with the Seneca regime. Thus, these modeling results indicated that the strain composition of the host (lake trout) population was not important in determining total number of lake trout deaths or total blood consumption attributable to the sea lamprey population, given the sea lamprey growth pattern. Regardless of water temperature regime, both blood consumption rate by sea lampreys and rate of sea lamprey-induced mortality on lake trout peaked in late October. Elevated blood consumption in late October appeared to be unrelated to changes in water temperature. The IBM approach should prove useful in optimizing control of sea lampreys in the Laurentian Great Lakes.

  4. Electricity, growth and development in India

    International Nuclear Information System (INIS)

    Debeir, Jean-Claude

    2014-01-01

    In India, the revenue generated by rapid economic growth have been used neither to relieve the enormous social injustices affecting the oppressed, nor to develop the physical-and especially electric power-infrastructure in a determined and planned way. This growth has not reduced poverty, and it has caused huge ecological degradations

  5. Fluorescence Imaging in the Red and Far-Red Region during Growth of Sunflower Plantlets. Diagnosis of the Early Infection by the Parasite Orobanche cumana

    Science.gov (United States)

    Ortiz-Bustos, Carmen M.; Pérez-Bueno, María L.; Barón, Matilde; Molinero-Ruiz, Leire

    2016-01-01

    Broomrape, caused by the root holoparasite Orobanche cumana, is the main biotic constraint to sunflower oil production worldwide. By the time broomrape emerges, most of the metabolic imbalance has been produced by O. cumana to sunflower plants. UV-induced multicolor fluorescence imaging (MCFI) provides information on the fluorescence emitted by chlorophyll (Chl) a of plants in the spectral bands with peaks near 680 nm (red, F680) and 740 nm (far-red, F740). In this work MCFI was extensively applied to sunflowers, either healthy or parasitized plants, for the first time. The distribution of red and far-red fluorescence was analyzed in healthy sunflower grown in pots under greenhouse conditions. Fluorescence patterns were analyzed across the leaf surface and throughout the plant by comparing the first four leaf pairs (LPs) between the second and fifth week of growth. Similar fluorescence patterns, with a delay of 3 or 4 days between them, were obtained for LPs of healthy sunflower, showing that red and far-red fluorescence varied with the developmental stage of the leaf. The use of F680 and F740 as indicators of sunflower infection by O. cumana during underground development stages of the parasite was also evaluated under similar experimental conditions. Early increases in F680 and F740 as well as decreases in F680/F740 were detected upon infection by O. cumana. Significant differences between inoculated and control plants depended on the LP that was considered at any time. Measurements of Chl contents and final total Chl content supported the results of MCFI, but they were less sensitive in differentiating healthy from inoculated plants. Sunflower infection was confirmed by the presence of broomrape nodules in the roots at the end of the experiment. The potential of MCFI in the red and far-red region for an early detection of O. cumana infection in sunflower was revealed. This technique might have a particular interest for early phenotyping in sunflower breeding

  6. Stages of growth in economic development

    Czech Academy of Sciences Publication Activity Database

    Kejak, Michal

    2003-01-01

    Roč. 27, č. 5 (2003), s. 771-800 ISSN 0165-1889 Institutional research plan: CEZ:AV0Z7085904 Keywords : growth * human capital * development Subject RIV: AH - Economics Impact factor: 0.690, year: 2003

  7. Intestinal parasites and tuberculosis

    Directory of Open Access Journals (Sweden)

    Anuar Alonso Cedeño-Burbano

    2017-10-01

    Conclusions: The available evidence was insufficient to affirm that intestinal parasites predispose to developing tuberculous. The studies carried out so far have found statistically insignificant results.

  8. Current progress in the development and use of artemether for chemoprophylaxis of major human schistosome parasites.

    Science.gov (United States)

    Utzinger, J; Xiao, S; Keiser, J; Chen, M; Zheng, J; Tanner, M

    2001-12-01

    Human schistosomiasis, a chronic and debilitating parasitic disease of the tropics, is ranked second after malaria in terms of public health importance. At present, there is no vaccine available, and chemotherapy is the cornerstone of schistosomiasis control. Praziquantel is the drug of choice. Oxamniquine has become difficult to obtain and metrifonate has recently been withdrawn from the market. Rapid re-infection following treatment and concern about praziquantel resistance called for the search of novel drugs for prevention and cure of schistosomiasis. Significant progress has been made with artemether, the methyl ether of dihydroartemisinin, already widely used for the treatment of malaria. The present article reviews the literature that led to the development of artemether for chemoprophylaxis in schistosomiasis, and it summarises the experiences so far obtained with its use to control schistosomiasis in different endemic settings. Topics covered include an overview of the global burden of schistosomiasis and approaches for its control; the nature and features of artemisinin and related derivatives, initially discovered as antimalarials, other bioactivities, and their recent discovery of antischistosomal properties; a historic account disclosing the antischistosomal activity of artemether; in vivo assessment of drug susceptibility of different developmental stages of schistosome parasites; artemether-induced pathology evidenced by scanning and transmission electron microscopy; the possible mechanism of action; in vivo studies with combination therapy of artemether and praziquantel; results of randomised controlled clinical trials of oral artemether for the prevention of patent infection and morbidity; and, ultimately the translation of this knowledge into public health action in different endemic settings towards a more integrated approach of schistosomiasis control.

  9. Subclinical Enteric Parasitic Infections and Growth Faltering in Infants in São Tomé, Africa: A Birth Cohort Study

    Science.gov (United States)

    Garzón, Marisol; Seixas, Jorge; Papoila, Ana Luísa; Alves, Marta

    2018-01-01

    The associations between enteric pathogenic parasites and growth in infants in São Tomé were explored using a refined anthropometric approach to recognize early growth faltering. A birth cohort study was conducted with follow-up to 24 months of age. Microscopic examination for protozoa and soil-transmitted helminths was performed. Anthropometric assessments included: z-scores for weight-for-length (WLZ), length-for-age (LAZ), weight (WAVZ) and length velocities (LAVZ), length-for-age difference (LAD), and wasting and stunting risk (≤−1 SD). Generalized additive mixed effects regression models were used to explore the associations between anthropometric parameters and enteric parasitic infections and cofactors. A total of 475 infants were enrolled, and 282 completed the study. The great majority of infants were asymptomatic. Giardia lamblia was detected in 35.1% of infants in at least one stool sample, helminths in 30.4%, and Cryptosporidium spp. in 14.7%. Giardia lamblia and helminth infections were significantly associated with mean decreases of 0.10 in LAZ and 0.32 in LAD, and of 0.16 in LAZ and 0.48 in LAD, respectively. Cryptosporidium spp. infection was significantly associated with a mean decrease of 0.43 in WAVZ and 0.55 in LAVZ. The underestimated association between subclinical parasitic enteric infections and mild growth faltering in infants should be addressed in public health policies. PMID:29621166

  10. POVERTY, GROWTH AND INEQUALITY IN DEVELOPING COUNTRIES

    Directory of Open Access Journals (Sweden)

    Guiga Housseima

    2012-01-01

    Full Text Available The purpose of this paper is to assess the position of some developing countries in relation to different theories about the relationship between poverty, growth and inequality. We conducted an econometric analysis through a study using panel data from 52 developing countries over the period 1990-2005, to determine the main sources of poverty reduction and show the interdependence between poverty, inequality and growth by using a system of simultaneous equations. This method is rarely applied econometric panel data and especially in the case studies on poverty. Our results indicate that the state investment in social sectors such as education and health and improving the living conditions of the rural population can promote economic growth and reducing inequality. Therefore, the Kuznets hypothesis is based on a relationship between economic growths to income inequality is most appropriate.

  11. Fiscal Policy and Growth in Developing Asia

    OpenAIRE

    Abdon, Arnelyn May; Estrada, Gemma Esther; Lee, Minsoo; Park, Donghyun

    2014-01-01

    In this paper we empirically explore the relationship between fiscal policy and economic growth in developing Asia. The region's overall level of taxes and government spending are substantially lower than those prevailing in advanced economies. Nevertheless, there are conceptual grounds why fiscal policy, including the composition of taxes and government spending, can have a significant effect on growth, as our empirical analysis shows. In line with economic theory, property taxes have a more...

  12. Financial Development, Growth and Equity in Brazil

    OpenAIRE

    Armando Castelar Pinheiro; Regis Bonelli

    2015-01-01

    Financial markets help to foster growth and productivity through their role in mobilizing savings to finance investment and production, selecting and monitoring investment projects, diversifying risks, and allowing investment and production to be carried out in the most productive scale and time frame. This paper examines the links between financial development, growth and equity. The focus is on the Brazilian case, but we also aim at contributing to a broader discussion on the role of financ...

  13. Filarial parasites develop faster and reproduce earlier in response to host immune effectors that determine filarial life expectancy.

    Science.gov (United States)

    Babayan, Simon A; Read, Andrew F; Lawrence, Rachel A; Bain, Odile; Allen, Judith E

    2010-10-19

    Humans and other mammals mount vigorous immune assaults against helminth parasites, yet there are intriguing reports that the immune response can enhance rather than impair parasite development. It has been hypothesized that helminths, like many free-living organisms, should optimize their development and reproduction in response to cues predicting future life expectancy. However, immune-dependent development by helminth parasites has so far eluded such evolutionary explanation. By manipulating various arms of the immune response of experimental hosts, we show that filarial nematodes, the parasites responsible for debilitating diseases in humans like river blindness and elephantiasis, accelerate their development in response to the IL-5 driven eosinophilia they encounter when infecting a host. Consequently they produce microfilariae, their transmission stages, earlier and in greater numbers. Eosinophilia is a primary host determinant of filarial life expectancy, operating both at larval and at late adult stages in anatomically and temporally separate locations, and is implicated in vaccine-mediated protection. Filarial nematodes are therefore able to adjust their reproductive schedules in response to an environmental predictor of their probability of survival, as proposed by evolutionary theory, thereby mitigating the effects of the immune attack to which helminths are most susceptible. Enhancing protective immunity against filarial nematodes, for example through vaccination, may be less effective at reducing transmission than would be expected and may, at worst, lead to increased transmission and, hence, pathology.

  14. Filarial parasites develop faster and reproduce earlier in response to host immune effectors that determine filarial life expectancy.

    Directory of Open Access Journals (Sweden)

    Simon A Babayan

    Full Text Available Humans and other mammals mount vigorous immune assaults against helminth parasites, yet there are intriguing reports that the immune response can enhance rather than impair parasite development. It has been hypothesized that helminths, like many free-living organisms, should optimize their development and reproduction in response to cues predicting future life expectancy. However, immune-dependent development by helminth parasites has so far eluded such evolutionary explanation. By manipulating various arms of the immune response of experimental hosts, we show that filarial nematodes, the parasites responsible for debilitating diseases in humans like river blindness and elephantiasis, accelerate their development in response to the IL-5 driven eosinophilia they encounter when infecting a host. Consequently they produce microfilariae, their transmission stages, earlier and in greater numbers. Eosinophilia is a primary host determinant of filarial life expectancy, operating both at larval and at late adult stages in anatomically and temporally separate locations, and is implicated in vaccine-mediated protection. Filarial nematodes are therefore able to adjust their reproductive schedules in response to an environmental predictor of their probability of survival, as proposed by evolutionary theory, thereby mitigating the effects of the immune attack to which helminths are most susceptible. Enhancing protective immunity against filarial nematodes, for example through vaccination, may be less effective at reducing transmission than would be expected and may, at worst, lead to increased transmission and, hence, pathology.

  15. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes.

    Science.gov (United States)

    Roques, Magali; Wall, Richard J; Douglass, Alexander P; Ramaprasad, Abhinay; Ferguson, David J P; Kaindama, Mbinda L; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, Zineb; Brady, Declan; Guttery, David S; Wheatley, Sally P; Yamano, Hiroyuki; Holder, Anthony A; Pain, Arnab; Wickstead, Bill; Tewari, Rita

    2015-11-01

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

  16. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

    KAUST Repository

    Roques, Magali; Wall, Richard J.; Douglass, Alexander P.; Ramaprasad, Abhinay; Ferguson, David J. P.; Kaindama, Mbinda L.; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, ‍ Zineb; Brady, Declan; Guttery, David S.; Wheatley, Sally P.; Yamano, Hiroyuki; Holder, Anthony A.; Pain, Arnab; Wickstead, Bill; Tewari, Rita

    2015-01-01

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

  17. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

    KAUST Repository

    Roques, Magali

    2015-11-13

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei.

  18. Malaria parasites: the great escape

    Directory of Open Access Journals (Sweden)

    Laurent Rénia

    2016-11-01

    Full Text Available Parasites of the genus Plasmodium have a complex life cycle. They alternate between their final mosquito host and their intermediate hosts. The parasite can be either extra- or intracellular, depending on the stage of development. By modifying their shape, motility, and metabolic requirements, the parasite adapts to the different environments in their different hosts. The parasite has evolved to escape the multiple immune mechanisms in the host that try to block parasite development at the different stages of their development. In this article, we describe the mechanisms reported thus far that allow the Plasmodium parasite to evade innate and adaptive immune responses.

  19. From commensalism to parasitism in Carapidae (Ophidiiformes: heterochronic modes of development?

    Directory of Open Access Journals (Sweden)

    Eric Parmentier

    2016-03-01

    Full Text Available Phenotypic variations allow a lineage to move into new regions of the adaptive landscape. The purpose of this study is to analyse the life history of the pearlfishes (Carapinae in a phylogenetic framework and particularly to highlight the evolution of parasite and commensal ways of life. Furthermore, we investigate the skull anatomy of parasites and commensals and discuss the developmental process that would explain the passage from one form to the other. The genus Carapus forms a paraphyletic grouping in contrast to the genus Encheliophis, which forms a monophyletic cluster. The combination of phylogenetic, morphologic and ontogenetic data clearly indicates that parasitic species derive from commensal species and do not constitute an iterative evolution from free-living forms. Although the head morphology of Carapus species differs completely from Encheliophis, C. homei is the sister group of the parasites. Interestingly, morphological characteristics allowing the establishment of the relation between Carapus homei and Encheliophis spp. concern the sound-producing mechanism, which can explain the diversification of the taxon but not the acquisition of the parasite morphotype. Carapus homei already has the sound-producing mechanism typically found in the parasite form but still has a commensal way of life and the corresponding head structure. Moreover, comparisons between the larval and adult Carapini highlight that the adult morphotype “Encheliophis” is obtained by going beyond the adult stage reached by Carapus. The entrance into the new adaptive landscape could have been realised by at least two processes: paedomorphosis and allometric repatterning.

  20. [Growth and development of children in Cuba].

    Science.gov (United States)

    Jordán Rodríguez, J; Bebel Agua, A; Rubén, M; Hernández, J

    1980-01-01

    During the years 1972 to 1974, a great scale study was carried out on development and growth taking at random a stratified sample of multiple stages of 50,311 children from birth to 20 years. Fifteen anthropometric dimensions were considered and evaluation was made of sexual development in both sexes. In girls, the age of menarche was registered. An X-ray of the hand was taken to 10% of the sample. One year later, 30% of the sample was X-rayed again to determine speed of growth. Response of the population was close to 94%. The importance of a national system of growth is recognized, together with the colaboration of the orgaism of masses to achieve these purposes. Information related with some of measurements reported is offered and comments related with these findings are made.

  1. Endogenous growth theory and regional development policy

    Directory of Open Access Journals (Sweden)

    Cvetanović Slobodan

    2015-01-01

    Full Text Available The numerous versions of endogenous explanations of economic growth emphasize the importance of technological change driving forces, as well as the existence of appropriate institutional arrangements. Endogenous growth theory contributes to a better understanding of various experiences with long-term growth of countries and regions. It changes the key assumptions of the Neoclassical growth theory and participates in the modern regional development physiology explanation. Based on these conclusions, the paper: a explicates the most important theoretical postulates of the theory, b explains the most important factors of economic growth in the regions in light of the Endogenous growth theory messages and c emphasizes the key determinants of regional competitiveness which in our view is conceptually between the phenomena of micro- and macro-competitiveness and represents their necessary and unique connection. First of all, micro-competitiveness is transformed into a regional competitiveness; then regional competitiveness is transformed into a macro-competitiveness. In turn, macro - influences the microeconomic competitiveness, and the circle is closed. After that, the process starts over again.

  2. Parasites: Water

    Science.gov (United States)

    ... Consultations, and General Public. Contact Us Parasites Home Water Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir Parasites can live in natural water sources. When outdoors, treat your water before drinking ...

  3. Disturbances of bone growth and development

    International Nuclear Information System (INIS)

    Ledesma-Medina, J.; Newman, B.; Oh, K.S.

    1988-01-01

    ''What is growth anyway? Can one talk about positive growth in childhood, neutral growth in maturity, and negative growth in old age? Our goal is to help promote normal positive growth in infants and children. To achieve this, we must be cognizant of the morphologic changes of both normal and abnormal bone formation as they are reflected in the radiographic image of the skeleton. The knowledge of the various causes and the pathophysiologic mechanisms of the disturbances of bone growth and development allows us to recognize the early radiographic manifestations. Endocrine and metabolic disorders affect the whole skeleton, but the early changes are best seen in the distal ends of the femurs, where growth rate is most rapid. In skeletal infections and in some vascular injuries two-or three-phase bone scintigraphy supercedes radiography early in the course of the disease. MRI has proved to be very helpful in the early detection of avascular bone necrosis, osteomyelitis, and tumor. Some benign bone tumors and many bone dysplasias have distinct and diagnostic radiographic findings that may preclude further studies. In constitutional diseases of bone, including chromosomal aberrations, skeletal surveys of the patient and all family members together with biochemical and cytogenetic studies are essential for both diagnosis and genetic counseling. Our role is to perform the least invasive and most informative diagnostic imaging modalities that corroborate the biochemical and histologic findings to establish the definitive diagnosis. Unrecognized, misdiagnosed, or improperly treated disturbance of bone growth can result in permanent deformity usually associated with disability. 116 references

  4. Genome-wide functional analysis of plasmodium protein phosphatases reveals key regulators of parasite development and differentiation

    KAUST Repository

    Guttery, David S.

    2014-07-09

    Reversible protein phosphorylation regulated by kinases and phosphatases controls many cellular processes. Although essential functions for the malaria parasite kinome have been reported, the roles of most protein phosphatases (PPs) during Plasmodium development are unknown. We report a functional analysis of the Plasmodium berghei protein phosphatome, which exhibits high conservation with the P. falciparum phosphatome and comprises 30 predicted PPs with differential and distinct expression patterns during various stages of the life cycle. Gene disruption analysis of P. berghei PPs reveals that half of the genes are likely essential for asexual blood stage development, whereas six are required for sexual development/sporogony in mosquitoes. Phenotypic screening coupled with transcriptome sequencing unveiled morphological changes and altered gene expression in deletion mutants of two N-myristoylated PPs. These findings provide systematic functional analyses of PPs in Plasmodium, identify how phosphatases regulate parasite development and differentiation, and can inform the identification of drug targets for malaria. © 2014 The Authors.

  5. Genome-wide functional analysis of plasmodium protein phosphatases reveals key regulators of parasite development and differentiation

    KAUST Repository

    Guttery, David  S.; Poulin, Benoit; Ramaprasad, Abhinay; Wall, Richard  J.; Ferguson, David  J.P.; Brady, Declan; Patzewitz, Eva-Maria; Whipple, Sarah; Straschil, Ursula; Wright, Megan  H.; Mohamed, Alyaa  M.A.H.; Radhakrishnan, Anand; Arold, Stefan T.; Tate, Edward  W.; Holder, Anthony  A.; Wickstead, Bill; Pain, Arnab; Tewari, Rita

    2014-01-01

    Reversible protein phosphorylation regulated by kinases and phosphatases controls many cellular processes. Although essential functions for the malaria parasite kinome have been reported, the roles of most protein phosphatases (PPs) during Plasmodium development are unknown. We report a functional analysis of the Plasmodium berghei protein phosphatome, which exhibits high conservation with the P. falciparum phosphatome and comprises 30 predicted PPs with differential and distinct expression patterns during various stages of the life cycle. Gene disruption analysis of P. berghei PPs reveals that half of the genes are likely essential for asexual blood stage development, whereas six are required for sexual development/sporogony in mosquitoes. Phenotypic screening coupled with transcriptome sequencing unveiled morphological changes and altered gene expression in deletion mutants of two N-myristoylated PPs. These findings provide systematic functional analyses of PPs in Plasmodium, identify how phosphatases regulate parasite development and differentiation, and can inform the identification of drug targets for malaria. © 2014 The Authors.

  6. Development of nuclear techniques in food and life engineering - Irradiation of food and drinking water to control parasitic infections

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Jong; Shin, Eun Hee; Guk, Sang Mee; Han, Eun Taek; Kim, Jae Lip [Seoul National University, Seoul (Korea)

    2000-04-01

    To prevent some intestinal trematodes which are highly prevalent in Korea, the effect of irradiation on fishes and metacercariae has been analyzed for control of parasites. The metacercariae of intestinal trematodes were irradiated with various doses, and the infection rates and developmental status were assayed for estimation of optimal radiation doses. In addition, to examine the differences of susceptibility to radiation among the parasites, superoxide dismutase (SOD) activities were determined, and degree of apoptosis were observed. As a result, 100 Gy irradiation was sufficient for Metagonimus yokogawai to redue their infectivity and development, and 200 Gy was for Gymnophalloides seoi. While Neodiplostomum seoulense, a kind of intestinal rematode, was proved to be highly susceptible to radiation, sparganum and Anisakis were resistant to radiation. These might result from the differences of SOD activity among parasites. The apoptosis of parasites was mainly observed after 100 Gy irradiation, and further study was required to decide whether these phenomenon influences the susceptibility to radiation. 21 refs., 7 figs., 4 tabs. (Author)

  7. Public Education and Growth in Developing Countries

    DEFF Research Database (Denmark)

    Schuppert, Christiane; Wirz, Nadja

    Human capital plays a key role in fostering technology adoption, the major source of economic growth in developing countries. Consequently, enhancing the level of human capital should be a matter of public concern. The present paper studies public education incentives in an environment in which...... governments can invest in human capital to facilitate the adoption of new technologies invented abroad or, instead, focus on consumptive public spending. Although human capital is pivotal for growth, the model reveals that incentives to invest in public education vanish if a country is poorly endowed...

  8. An improved axenic system for studying pre-infection development of the parasitic plant Orobanche ramosa.

    Science.gov (United States)

    González-Verdejo, Clara Isabel; Barandiaran, Xabier; Moreno, Maria Teresa; Cubero, Jose Ignacio; Di Pietro, Antonio

    2005-11-01

    stages of parasitic development in Orobanche.

  9. Development and reproductive biology of the egg-pupal parasite, Fopius arisanus in Anastrepha suspensa, a new tephritid host

    International Nuclear Information System (INIS)

    Lawrence, Pauline O.; Harris, Ernest J.; Bautist, Renato C.

    2000-01-01

    Fopius (=Biosteres) arisanus (Sonan) (=Opius oophilus Fullaway) (Hymenoptera: Braconidae) is a solitary egg parasite (parasitoid) that attacks tephritid fruit fly (Diptera: Tephritidae) eggs and first instars (Haramoto 1953, Clausen et al. 1965, Harris and Okamoto 1991). It completes its development within the host's larva and pupa and emerges from the latter as an adult and as such, is an egg-pupal endoparasite. F. arisanus is known to attack at least seven tephritid fruit fly species (Wharton and Gilstrap 1983) and appears to be the only egg-pupal parasite of tephritids in the Western Hemisphere. It is considered to be the most successful of the parasites that attack the Oriental fruit fly, Bactrocera dorsalis (Hendel) and the Mediterranean fruit fly (Medfly), Ceratitis capitata (Weidmann) in Hawaii (Knipling 1995), resulting in 74-92% of total parasites recovered from both host species (Wong and Ramadan 1987). However, in Malaysia, Palacio et al. (1992) found that F. arisanus was outcompeted by the larval endoparasite, Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) in multiple parasitised B. dorsalis. While several larval parasites of tephritids had been cultured successfully in the laboratory (Ramadan 1991) and utilised in inundative release programmes, F. arisanus proved difficult to maintain in culture. In recent years, a laboratory strain of F. arisanus (termed the 'Harris strain') has been established on B. dorsalis (Harris and Okamoto 1991). Efforts are currently in progress to mass rear this strain on the Medfly and other tephritid pests. F. arisanus was first released into Florida from Hawaii in 1974-75 as a biological control agent against the Caribbean fruit fly (Caribfly) Anastrepha suspensa (Loew) (Diptera: Tephritidae) but this was unsuccessful (Baranowski et al. 1993). Interestingly, it was also introduced into Costa Rica from Hawaii and was subsequently reared from puparia of Anastrepha spp. (Wharton et al. 1981), indicating its

  10. Interaction between Orobanche crenata and its host legumes: unsuccessful haustorial penetration and necrosis of the developing parasite.

    Science.gov (United States)

    Pérez-DE-Luque, A; Rubiales, D; Cubero, J I; Press, M C; Scholes, J; Yoneyama, K; Takeuchi, Y; Plakhine, D; Joel, D M

    2005-05-01

    Orobanche species represent major constraints to crop production in many parts of the world as they reduce yield and alter root/shoot allometry. Although much is known about the histology and effect of Orobanche spp. on susceptible hosts, less is known about the basis of host resistance to these parasites. In this work, histological aspects related to the resistance of some legumes to Orobanche crenata have been investigated in order to determine which types of resistance responses are involved in the unsuccessful penetration of O. crenata. Samples of resistance reactions against O. crenata on different genotypes of resistant legumes were collected. The samples were fixed, sectioned and stained using different procedures. Sections were observed using a transmission light microscope and by epi-fluorescence. Lignification of endodermal and pericycle host cells seems to prevent parasite intrusion into the root vascular cylinder at early infection stages. But in other cases, established tubercles became necrotic and died. Contrary to some previous studies, it was found that darkening at the infection site in these latter cases does not correspond to death of host tissues, but to the secretion of substances that fill the apoplast in the host-parasite interface and in much of the infected host tissues. The secretions block neighbouring host vessels. This may interfere with the nutrient flux between host and parasite, and may lead to necrosis and death of the developing parasite. The unsuccessful penetration of O. crenata seedlings into legume roots cannot be attributed to cell death in the host. It seems to be associated with lignification of host endodermis and pericycle cells at the penetration site. The accumulation of secretions at the infection site, may lead to the activation of xylem occlusion, another defence mechanism, which may cause further necrosis of established tubercles.

  11. Social Parasites

    Science.gov (United States)

    Lopez, Miguel A.; Nguyen, HoangKim T.; Oberholzer, Michael; Hill, Kent L.

    2011-01-01

    Summary of recent advances Protozoan parasites cause tremendous human suffering worldwide, but strategies for therapeutic intervention are limited. Recent studies illustrate that the paradigm of microbes as social organisms can be brought to bear on questions about parasite biology, transmission and pathogenesis. This review discusses recent work demonstrating adaptation of social behaviors by parasitic protozoa that cause African sleeping sickness and malaria. The recognition of social behavior and cell-cell communication as a ubiquitous property of bacteria has transformed our view of microbiology, but protozoan parasites have not generally been considered in this context. Works discussed illustrate the potential for concepts of sociomicrobiology to provide insight into parasite biology and should stimulate new approaches for thinking about parasites and parasite-host interactions. PMID:22020108

  12. Robust inducible Cre recombinase activity in the human malaria parasite Plasmodium falciparum enables efficient gene deletion within a single asexual erythrocytic growth cycle.

    Science.gov (United States)

    Collins, Christine R; Das, Sujaan; Wong, Eleanor H; Andenmatten, Nicole; Stallmach, Robert; Hackett, Fiona; Herman, Jean-Paul; Müller, Sylke; Meissner, Markus; Blackman, Michael J

    2013-05-01

    Asexual blood stages of the malaria parasite, which cause all the pathology associated with malaria, can readily be genetically modified by homologous recombination, enabling the functional study of parasite genes that are not essential in this part of the life cycle. However, no widely applicable method for conditional mutagenesis of essential asexual blood-stage malarial genes is available, hindering their functional analysis. We report the application of the DiCre conditional recombinase system to Plasmodium falciparum, the causative agent of the most dangerous form of malaria. We show that DiCre can be used to obtain rapid, highly regulated site-specific recombination in P. falciparum, capable of excising loxP-flanked sequences from a genomic locus with close to 100% efficiency within the time-span of a single erythrocytic growth cycle. DiCre-mediated deletion of the SERA5 3' UTR failed to reduce expression of the gene due to the existence of alternative cryptic polyadenylation sites within the modified locus. However, we successfully used the system to recycle the most widely used drug resistance marker for P. falciparum, human dihydrofolate reductase, in the process producing constitutively DiCre-expressing P. falciparum clones that have broad utility for the functional analysis of essential asexual blood-stage parasite genes. © 2013 John Wiley & Sons Ltd.

  13. Conjoint effect of oil-seed cakes and Pseudomonas fluorescens on the growth of chickpea in relation to the management of plant-parasitic nematodes

    Directory of Open Access Journals (Sweden)

    Rose Rizvi

    2012-12-01

    Full Text Available Soil application of organics has been explored as an alternative means of organic management of plant-parasitic nematodes. Efficiency of different oil-seed cakes of neem (Azadirachta indica, castor (Ricinus communis, groundnut (Arachis hypogaea, linseed (Linum usitatissimum, sunflower (Helianthus annuus and soybean (Glycine max were evaluated in field conditions with association of Pseudomonas fluorescens in relation to growth parameters of chickpea and population of plant-parasitic nematodes. Their efficacious nature was highly effective in reducing the population of these dominant soil nematodes. Significant improvement was observed in plant-growth parameters such as plant weight, percent pollen fertility, pod numbers, root-nodulation and chlorophyll content of chickpea, seemed to be due to reduction in disease incidence and might be due to growth promoting substances secreted by P. fluorescens. The multiplication rate of nematodes was less in the presence of P. fluorescens as compared to its absence. Most effective combination of P. fluorescens was observed with neem cake.

  14. Population growth and development: the Kenyan experience.

    Science.gov (United States)

    Nyamwange, M

    1995-01-01

    Rapid population growth in Kenya and high fertility impacts negatively on economic development. The growth and high fertility results in declines in gross national product, per capita food consumption, and land quality; a high dependency ratio; urban crowding; and inadequate health systems. East Africa has the highest crude birth rates in Africa, and Kenya has the highest birth rate of 54/1000 population in East Africa. The African crude death rate is 50% higher than the world average, but Kenya's death rate is the lowest in East Africa and comparable to North American and European death rates. Kenya has the highest rate of natural increase of about 4%. Population growth rates rose over the decades. Kenya's average population density is well above the sub-Saharan African average and much lower than very high density countries. Population is unequally distributed. Regional densities are widely divergent, and the highest densities in Western province are well above densities in Rwanda and Burundi. Urban growth has increased, as has migration to urban areas. Nairobi has 57% of urban population. Improved health and nutrition have contributed to increased life expectancy. The desired family size is large. The impact of demographic factors on economic conditions is evident in the decline in gross national product per capita growth to under 1% during 1972-88. A slight upswing occurred during 1988-93, but other crises are emerging. Food production has not kept pace with population growth. Production has been low due to serious land degradation, short fallow periods, and traditional farming practices. Population pressure has forced families to shift agriculture onto marginal lands, and desertification has increased. A growing proportion of the population is unemployed or underemployed. Population programs should address the underlying conditions for fertility decline.

  15. Nuclear DNA replication and repair in parasites of the genus Leishmania: Exploiting differences to develop innovative therapeutic approaches.

    Science.gov (United States)

    Uzcanga, Graciela; Lara, Eliana; Gutiérrez, Fernanda; Beaty, Doyle; Beske, Timo; Teran, Rommy; Navarro, Juan-Carlos; Pasero, Philippe; Benítez, Washington; Poveda, Ana

    2017-03-01

    Leishmaniasis is a common tropical disease that affects mainly poor people in underdeveloped and developing countries. This largely neglected infection is caused by Leishmania spp, a parasite from the Trypanosomatidae family. This parasitic disease has different clinical manifestations, ranging from localized cutaneous to more harmful visceral forms. The main limitations of the current treatments are their high cost, toxicity, lack of specificity, and long duration. Efforts to improve treatments are necessary to deal with this infectious disease. Many approved drugs to combat diseases as diverse as cancer, bacterial, or viral infections take advantage of specific features of the causing agent or of the disease. Recent evidence indicates that the specific characteristics of the Trypanosomatidae replication and repair machineries could be used as possible targets for the development of new treatments. Here, we review in detail the molecular mechanisms of DNA replication and repair regulation in trypanosomatids of the genus Leishmania and the drugs that could be useful against this disease.

  16. History and development of research on wildlife parasites in southern Africa, with emphasis on terrestrial mammals, especially ungulates

    Directory of Open Access Journals (Sweden)

    Kerstin Junker

    2015-04-01

    Full Text Available The history of wildlife parasitology in South Africa, and to some extent southern Africa, is reviewed, giving a brief overview of the early years and following its development from the founding of the Onderstepoort Veterinary Institute in 1908 until the turn of the century. An emphasis is placed on game species. The main findings on protozoan parasites, including those of carnivores, are presented, starting in the 1890s and leading up to the first decade of the 21st century. Important developments with regard to the studies of arthropod and helminth parasites took place during a period of three decades, starting from the 1970s. Because of the sheer volume of work done by parasitologists during this time, this particular part of the overview concentrates on South African authors or authors working in South Africa at the time, and is limited to hosts that are members of the order Perissodactyla and the superorder Cetartiodactyla.

  17. History and development of research on wildlife parasites in southern Africa, with emphasis on terrestrial mammals, especially ungulates

    Science.gov (United States)

    Junker, Kerstin; Horak, Ivan G.; Penzhorn, Banie

    2014-01-01

    The history of wildlife parasitology in South Africa, and to some extent southern Africa, is reviewed, giving a brief overview of the early years and following its development from the founding of the Onderstepoort Veterinary Institute in 1908 until the turn of the century. An emphasis is placed on game species. The main findings on protozoan parasites, including those of carnivores, are presented, starting in the 1890s and leading up to the first decade of the 21st century. Important developments with regard to the studies of arthropod and helminth parasites took place during a period of three decades, starting from the 1970s. Because of the sheer volume of work done by parasitologists during this time, this particular part of the overview concentrates on South African authors or authors working in South Africa at the time, and is limited to hosts that are members of the order Perissodactyla and the superorder Cetartiodactyla. PMID:25830101

  18. Social and economic growth of developing nations

    International Nuclear Information System (INIS)

    Gregersen, H.M.; Laarman, J.G.

    1989-01-01

    This paper reports on social and economic growth of developing nations. Trees and forests are often of immeasurable importance to developing countries of the world. To be of value, however, effective and efficient institutions, programs, and policies must be designed and focused on such resources. Forest economics and policy researchers can contribute much to such activities. To be most effective, forest economics research should be designed to improve understanding of social forestry, watershed management, and nontimber forest outputs; enhance ability to effectively address environmental consequences of forestry development; heighten skill in guiding development of industrial forestry enterprises; and improve effectiveness of international aid for forestry development. Guided by such strategic directions, forest economics research can contribute much to the economic and social well-being of developing nations

  19. Mammalian oocyte growth and development in vitro.

    Science.gov (United States)

    Eppig, J J; O'Brien, M; Wigglesworth, K

    1996-06-01

    This paper is a review of the current status of technology for mammalian oocyte growth and development in vitro. It compares and contrasts the characteristics of the various culture systems that have been devised for the culture of either isolated preantral follicles or the oocyte-granulosa cell complexes form preantral follicles. The advantages and disadvantages of these various systems are discussed. Endpoints for the evaluation of oocyte development in vitro, including oocyte maturation and embryogenesis, are described. Considerations for the improvement of the culture systems are also presented. These include discussions of the possible effects of apoptosis and inappropriate differentiation of oocyte-associated granulosa cells on oocyte development. Finally, the potential applications of the technology for oocyte growth and development in vitro are discussed. For example, studies of oocyte development in vitro could help to identify specific molecules produced during oocyte development that are essential for normal early embryogenesis and perhaps recognize defects leading to infertility or abnormalities in embryonic development. Moreover, the culture systems may provide the methods necessary to enlarge the populations of valuable agricultural, pharmaceutical product-producing, and endangered animals, and to rescue the oocytes of women about to undergo clinical procedures that place oocytes at risk.

  20. Growth models and analysis of development

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, G

    1979-10-01

    This paper deals with remnants of neoclassical elements in Keynesian and post-Keynesian thought, and attempts to demonstrate that the elimination of these elements from our modes of thinking would not impoverish economic analysis as a means of solving real problems. In the Keynesian analysis the causation from investment to savings is exhibited in terms of income determination. When put in terms of a capital-theory model, the vector of savings is represented in two ways: real savings and counterpart real savings. The former coincides with the investment vector and the latter with the vector of consumption goods foregone for diverting resources towards equipment making. Thus the Keynesian causation in capital theory terms makes the concept of national savings as an independent variable redudant. The Robinsonian causation in a golden age with full employment and its reversal of direction in a steady state with non-employment are then considered. But in each of these, variables like rate of savings and output/capital ratio are found to be dormant variables. They are termed as null variables which, being of no account in both full-employment and unemployment situations, could, without loss, be deleted from the repertory of analytical tools. The Harrod formula of warranted rate of growth, when put in causal form, thus becomes a redundant portion of economics of growth. The real determinants of the growth rate and real wage rate on which the analysis of growth or of development should be based, are also depicted.

  1. The Cytoplasmic Prolyl-tRNA Synthetase of the Malaria Parasite is a Dual-Stage Target for Drug Development

    Science.gov (United States)

    Herman, Jonathan D.; Pepper, Lauren R.; Cortese, Joseph F.; Estiu, Guillermina; Galinsky, Kevin; Zuzarte-Luis, Vanessa; Derbyshire, Emily R.; Ribacke, Ulf; Lukens, Amanda K.; Santos, Sofia A.; Patel, Vishal; Clish, Clary B.; Sullivan, William J.; Zhou, Huihao; Bopp, Selina E.; Schimmel, Paul; Lindquist, Susan; Clardy, Jon; Mota, Maria M.; Keller, Tracy L.; Whitman, Malcolm; Wiest, Olaf; Wirth, Dyann F.; Mazitschek, Ralph

    2015-01-01

    The emergence of drug resistance is a major limitation of current antimalarials. The discovery of new druggable targets and pathways including those that are critical for multiple life cycle stages of the malaria parasite is a major goal for the development of the next-generation of antimalarial drugs. Using an integrated chemogenomics approach that combined drug-resistance selection, whole genome sequencing and an orthogonal yeast model, we demonstrate that the cytoplasmic prolyl-tRNA synthetase (PfcPRS) of the malaria parasite Plasmodium falciparum is a biochemical and functional target of febrifugine and its synthetic derivatives such as halofuginone. Febrifugine is the active principle of a traditional Chinese herbal remedy for malaria. We show that treatment with febrifugine derivatives activated the amino acid starvation response in both P. falciparum and a transgenic yeast strain expressing PfcPRS. We further demonstrate in the P. berghei mouse model of malaria that halofuginol, a new halofuginone analog that we developed, is highly active against both liver and asexual blood stages of the malaria parasite. Halofuginol, unlike halofuginone and febrifugine, is well tolerated at efficacious doses, and represents a promising lead for the development of dual-stage next generation antimalarials. PMID:25995223

  2. The NAD+ metabolism of Leishmania, notably the enzyme nicotinamidase involved in NAD+ salvage, offers prospects for development of anti-parasite chemotherapy.

    Science.gov (United States)

    Michels, Paul A M; Avilán, Luisana

    2011-10-01

    NAD+ plays multiple, essential roles in the cell. As a cofactor in many redox reactions it is key in the cellular energy metabolism and as a substrate it participates in many reactions leading to a variety of covalent modifications of enzymes with major roles in regulation of expression and metabolism. Cells may have the ability to produce this metabolite either via alternative de novo synthesis pathways and/or by different salvage pathways. In this issue of Molecular Microbiology, Gazanion et al. (2011) demonstrate that Leishmania species can only rely on the salvage of NAD+ building blocks. One of the enzymes involved, nicotinamidase, is absent from human cells. The enzyme is important for growth of Leishmania infantum and essential for establishing an infection. The crystal structure of the parasite protein has been solved and shows prospects for design of inhibitors to be used as leads for development of new drugs. Indeed, NAD+ metabolism is currently being considered as a promising drug target in various diseases and the vulnerability of Leishmania for interference of this metabolism has been proved in previous work by the same group, by showing that administration of NAD+ precursors has detrimental effect on the pathogenic, amastigote stage of this parasite. © 2011 Blackwell Publishing Ltd.

  3. The fatty acid biosynthesis enzyme FabI plays a key role in the development of liver-stage malarial parasites.

    Science.gov (United States)

    Yu, Min; Kumar, T R Santha; Nkrumah, Louis J; Coppi, Alida; Retzlaff, Silke; Li, Celeste D; Kelly, Brendan J; Moura, Pedro A; Lakshmanan, Viswanathan; Freundlich, Joel S; Valderramos, Juan-Carlos; Vilcheze, Catherine; Siedner, Mark; Tsai, Jennifer H-C; Falkard, Brie; Sidhu, Amar Bir Singh; Purcell, Lisa A; Gratraud, Paul; Kremer, Laurent; Waters, Andrew P; Schiehser, Guy; Jacobus, David P; Janse, Chris J; Ager, Arba; Jacobs, William R; Sacchettini, James C; Heussler, Volker; Sinnis, Photini; Fidock, David A

    2008-12-11

    The fatty acid synthesis type II pathway has received considerable interest as a candidate therapeutic target in Plasmodium falciparum asexual blood-stage infections. This apicoplast-resident pathway, distinct from the mammalian type I process, includes FabI. Here, we report synthetic chemistry and transfection studies concluding that Plasmodium FabI is not the target of the antimalarial activity of triclosan, an inhibitor of bacterial FabI. Disruption of fabI in P. falciparum or the rodent parasite P. berghei does not impede blood-stage growth. In contrast, mosquito-derived, FabI-deficient P. berghei sporozoites are markedly less infective for mice and typically fail to complete liver-stage development in vitro. This defect is characterized by an inability to form intrahepatic merosomes that normally initiate blood-stage infections. These data illuminate key differences between liver- and blood-stage parasites in their requirements for host versus de novo synthesized fatty acids, and create new prospects for stage-specific antimalarial interventions.

  4. Functional characterization of malaria parasites deficient in the K+ channel Kch2

    DEFF Research Database (Denmark)

    Ellekvist, Peter; Mlambo, Godfree; Kumar, Nirbhay

    2017-01-01

    parasite P. berghei, the functional significance of K+ channel homologue PbKch2 was studied using targeted gene knock-out. The knockout parasites were characterized in a mouse model in terms of growth-kinetics and infectivity in the mosquito vector. Furthermore, using a tracer-uptake technique with 86Rb...... of forming oocysts in female Anopheles stephensi mosquitoes. 86Rb+ uptake in Kch2-deficient blood-stage P. berghei parasites (Kch2-null) did not differ from that of wild-type (WT) parasites. About two-thirds of the 86Rb+ uptake in WT and in Kch2-null parasites could be inhibited by K+ channel blockers...... and could be inferred to the presence of functional Kch1 in Kch2 knockout parasites. Kch2 is therefore not required for transport of K+ in P. berghei and is not essential to mosquito-stage sporogonic development of the parasite....

  5. Genetic Validation of Leishmania donovani Lysyl-tRNA Synthetase Shows that It Is Indispensable for Parasite Growth and Infectivity

    OpenAIRE

    Sanya Chadha; N. Arjunreddy Mallampudi; Debendra K. Mohapatra; Rentala Madhubala; Ira J. Blader; Greg Matlashewski; Frederick Buckner

    2017-01-01

    ABSTRACT Leishmania donovani is a protozoan parasite that causes visceral leishmaniasis. Increasing resistance and severe side effects of existing drugs have led to the need to identify new chemotherapeutic targets. Aminoacyl-tRNA synthetases (aaRSs) are ubiquitous and are required for protein synthesis. aaRSs are known drug targets for bacterial and fungal pathogens. Here, we have characterized and evaluated the essentiality of L.?donovani lysyl-tRNA synthetase (LdLysRS). Two different codin...

  6. Plasmodium berghei Δp52&p36 parasites develop independent of a parasitophorous vacuole membrane in Huh-7 liver cells.

    Science.gov (United States)

    Ploemen, Ivo H J; Croes, Huib J; van Gemert, Geert-Jan J; Wijers-Rouw, Mietske; Hermsen, Cornelus C; Sauerwein, Robert W

    2012-01-01

    The proteins P52 and P36 are expressed in the sporozoite stage of the murine malaria parasite Plasmodium berghei. Δp52&p36 sporozoites lacking expression of both proteins are severely compromised in their capability to develop into liver stage parasites and abort development soon after invasion; presumably due to the absence of a parasitophorous vacuole membrane (PVM). However, a small proportion of P. berghei Δp52&p36 parasites is capable to fully mature in hepatocytes causing breakthrough blood stage infections. We have studied the maturation of replicating Δp52&p36 parasites in cultured Huh-7 hepatocytes. Approximately 50% of Δp52&p36 parasites developed inside the nucleus of the hepatocyte but did not complete maturation and failed to produce merosomes. In contrast cytosolic Δp52&p36 parasites were able to fully mature and produced infectious merozoites. These Δp52&p36 parasites developed into mature schizonts in the absence of an apparent parasitophorous vacuole membrane as shown by immunofluorescence and electron microscopy. Merozoites derived from these maturing Δp52&p36 liver stages were infectious for C57BL/6 mice.

  7. Effect of Giardia infection on growth and psychomotor development of children aged 0-5 years.

    Science.gov (United States)

    Simsek, Z; Zeyrek, F Yildiz; Kurcer, M A

    2004-04-01

    Giardiasis, an intestinal protozoan infection caused by Giardia intestinalis, is common in southeastern Anatolia, Turkey. In this cross-sectional survey, to investigate the role of giardiasis on growth and psychomotor development, we studied 160 children aged 0-5 years. Data were collected using a structured questionnaire, anthropometry, Ankara Developmental Screening Inventory, and laboratory analysis of fecal samples. The results showed that 50 per cent of the subjects were infected with at least one pathogen of intestinal parasitic infections. Giardia intestinalis was the most frequent pathogenic parasite. Giardia-infected children had a risk for stunted (OR = 7.67, 95 per cent CI = 2.25-26.16; p = 0.001) and poor psychomotor development (OR = 2.68, 95 per cent CI = 1.09-6.58; p = 0.030). The data indicate that Giardia intestinalis infection has an adverse impact on child linear growth and psychomotor development. In the primary healthcare centers, during the programme of the monitoring growth and developmental status of children, following children in terms of Giardia, diagnosis and treatment will have a positive effect on child health.

  8. Monitoring Plasmodium falciparum growth and development by UV flow cytometry using an optimized Hoechst-thiazole orange staining strategy.

    Science.gov (United States)

    Grimberg, Brian T; Erickson, John J; Sramkoski, R Michael; Jacobberger, James W; Zimmerman, Peter A

    2008-06-01

    The complex life cycle of Plasmodium falciparum (Pf) makes it difficult to limit infections and reduce the risk of severe malaria. Improved understanding of Pf blood-stage growth and development would provide new opportunities to evaluate and interfere with successful completion of the parasite's life cycle. Cultured blood stage Pf was incubated with Hoechst 33342 (HO) and thiazole orange (TO) to stain DNA and total nucleic acids, respectively. Correlated HO and TO fluorescence emissions were then measured by flow cytometry. Complex bivariate data patterns were analyzed by manual cluster gating to quantify parasite life cycle stages. The permutations of viable staining with both reagents were tested for optimal detection of parasitized RBC (pRBC). Pf cultures were exposed to HO and TO simultaneously to achieve optimal staining of pRBC and consistent quantification of early and late stages of the replicative cycle (rings through schizonts). Staining of Pf nucleic acids allows for analysis of parasite development in the absence of fixatives, lysis, or radioactivity to enable examination of erythrocytes from parasite invasion through schizont rupture using sensitive and rapid assay procedures. Investigation of the mechanisms by which anti-malarial drugs and antibodies act against different Pf lifecycle stages will be aided by this cytometric strategy. (c) 2008 International Society for Advancement of Cytometry.

  9. Strongyloides stercoralis age-1: a potential regulator of infective larval development in a parasitic nematode.

    Directory of Open Access Journals (Sweden)

    Jonathan D Stoltzfus

    Full Text Available Infective third-stage larvae (L3i of the human parasite Strongyloides stercoralis share many morphological, developmental, and behavioral attributes with Caenorhabditis elegans dauer larvae. The 'dauer hypothesis' predicts that the same molecular genetic mechanisms control both dauer larval development in C. elegans and L3i morphogenesis in S. stercoralis. In C. elegans, the phosphatidylinositol-3 (PI3 kinase catalytic subunit AGE-1 functions in the insulin/IGF-1 signaling (IIS pathway to regulate formation of dauer larvae. Here we identify and characterize Ss-age-1, the S. stercoralis homolog of the gene encoding C. elegans AGE-1. Our analysis of the Ss-age-1 genomic region revealed three exons encoding a predicted protein of 1,209 amino acids, which clustered with C. elegans AGE-1 in phylogenetic analysis. We examined temporal patterns of expression in the S. stercoralis life cycle by reverse transcription quantitative PCR and observed low levels of Ss-age-1 transcripts in all stages. To compare anatomical patterns of expression between the two species, we used Ss-age-1 or Ce-age-1 promoter::enhanced green fluorescent protein reporter constructs expressed in transgenic animals for each species. We observed conservation of expression in amphidial neurons, which play a critical role in developmental regulation of both dauer larvae and L3i. Application of the PI3 kinase inhibitor LY294002 suppressed L3i in vitro activation in a dose-dependent fashion, with 100 µM resulting in a 90% decrease (odds ratio: 0.10, 95% confidence interval: 0.08-0.13 in the odds of resumption of feeding for treated L3i in comparison to the control. Together, these data support the hypothesis that Ss-age-1 regulates the development of S. stercoralis L3i via an IIS pathway in a manner similar to that observed in C. elegans dauer larvae. Understanding the mechanisms by which infective larvae are formed and activated may lead to novel control measures and treatments for

  10. De Novo Assembly and Characterization of the Transcriptome of the Parasitic Weed Dodder Identifies Genes Associated with Plant Parasitism1[C][W][OPEN

    Science.gov (United States)

    Ranjan, Aashish; Ichihashi, Yasunori; Farhi, Moran; Zumstein, Kristina; Townsley, Brad; David-Schwartz, Rakefet; Sinha, Neelima R.

    2014-01-01

    Parasitic flowering plants are one of the most destructive agricultural pests and have major impact on crop yields throughout the world. Being dependent on finding a host plant for growth, parasitic plants penetrate their host using specialized organs called haustoria. Haustoria establish vascular connections with the host, which enable the parasite to steal nutrients and water. The underlying molecular and developmental basis of parasitism by plants is largely unknown. In order to investigate the process of parasitism, RNAs from different stages (i.e. seed, seedling, vegetative strand, prehaustoria, haustoria, and flower) were used to de novo assemble and annotate the transcriptome of the obligate plant stem parasite dodder (Cuscuta pentagona). The assembled transcriptome was used to dissect transcriptional dynamics during dodder development and parasitism and identified key gene categories involved in the process of plant parasitism. Host plant infection is accompanied by increased expression of parasite genes underlying transport and transporter categories, response to stress and stimuli, as well as genes encoding enzymes involved in cell wall modifications. By contrast, expression of photosynthetic genes is decreased in the dodder infective stages compared with normal stem. In addition, genes relating to biosynthesis, transport, and response of phytohormones, such as auxin, gibberellins, and strigolactone, were differentially expressed in the dodder infective stages compared with stems and seedlings. This analysis sheds light on the transcriptional changes that accompany plant parasitism and will aid in identifying potential gene targets for use in controlling the infestation of crops by parasitic weeds. PMID:24399359

  11. Transglutaminase activity in equine strongyles and its potential role in growth and development.

    Science.gov (United States)

    Rao, U R; Chapman, M R; Singh, R N; Mehta, K; Klei, T R

    1999-06-01

    Transglutaminases (E.C. 2.3.3.13) are a family of Ca(2+)-dependent enzymes that stabilize protein structure by catalyzing the formation of isopeptide bonds. A novel form of transglutaminase has been identified and characterized that seem to play an important role in growth, development, and molting in adult and larval stages of filarial nematodes. The aim of this study was to identify the ubiquitous nature of this enzyme in other nematodes and to measure its significance to larval growth, molting, and development. For this purpose, equine Strongylus spp. were used. Activity of this enzyme was identified in extracts of larvae and adults of Strongylus vulgaris, S. edentatus, Parascaris equorum and Cylicocyclus insigne. The significance of transglutaminase in the early growth and development of Strongylus vulgaris, S. edentatus and S. equinus was tested by adding specific inhibitors, monodansylcadaverine (MDC) or cystamine (CS), to in vitro cultures of third (L3) and fourth stage larvae (L4). The viability, molting and growth of these nematode species were affected by both inhibitors. Cystamine promoted abnormal development of Strongylus edentatus L3, resulting in an aberrant expansion of the anterior end. Addition of these inhibitors to cultures of L4 also reduced growth of the three species. The results indicated that transglutaminase is present in a wide array of nematode parasites and may be important in growth and development of their larval stages.

  12. Disturbance of physical growth and development

    International Nuclear Information System (INIS)

    Nakamura, Nori; Akiyama, Mitoshi

    1992-01-01

    It has been thought that physical growth, such as height, weight, sitting height, chest circumference, and head circumference, was retarded among A-bomb survivors exposed in childhood. In this paper, physical growth and development among A-bomb survivors are discussed in the context of exposure doses estimated by T65D. The 1966-1968 survey for Hiroshima's survivors has shown that there was no consistent tendency for either height or weight among A-bomb survivors under the age of 11 when the estimated doses were 99 rad or less. In the group of 100 rad or more, however, both height and weight were found to be lower than the average among these age groups of A-bomb survivors. Similar findings were observed among girls in Nagasaki's survivors. According to the distance from the hypocenter, height was definitely shorter at the age of both 10 and 17 years among in uterus exposed A-bomb survivors in the group of 100 rad or more than the group of less than 100 rad; this was common in both Hiroshima and Nagasaki. Similarly, head circumstance was also smaller at the age of both 10 and 17 years in such A-bomb survivors. There was no evidence of correlation between physical growth and A-bomb radiation in F 1 offspring of A-bomb survivors. (N.K.)

  13. Inclusive growth versus pro-poor growth: Implications for tourism development

    NARCIS (Netherlands)

    Bakker, Martine; Messerli, H.R.

    2017-01-01

    Inclusive growth and pro-poor growth are terms embraced but not fully understood in the tourism community. This paper discusses the main concepts of inclusive growth and their implication for tourism development across the developing world. Is inclusive growth simply another term for pro-poor in

  14. Fish parasites

    DEFF Research Database (Denmark)

    This book contains 22 chapters on some of the most important parasitic diseases in wild and farmed fish. International experts give updated reviews and provide solutions to the problems......This book contains 22 chapters on some of the most important parasitic diseases in wild and farmed fish. International experts give updated reviews and provide solutions to the problems...

  15. Parasitic diseases

    International Nuclear Information System (INIS)

    Rozenshtraukh, L.S.

    1983-01-01

    Foundations of roentgenological semiotics of parasitic diseases of lungs, w hich are of the greatest practical value, are presented. Roentgenological pictu res of the following parasitic diseases: hydatid and alveolar echinococcosis, pa ragonimiasis, toxoplasmosis, ascariasis, amebiasis, bilharziasis (Schistosomias is) of lungs, are considered

  16. Effect of BMAP-28 antimicrobial peptides on Leishmania major promastigote and amastigote growth: role of leishmanolysin in parasite survival.

    Directory of Open Access Journals (Sweden)

    Miriam A Lynn

    Full Text Available Protozoan parasites, such as Leishmania, still pose an enormous public health problem in many countries throughout the world. Current measures are outdated and have some associated drug resistance, prompting the search into novel therapies. Several innovative approaches are under investigation, including the utilization of host defence peptides (HDPs as emerging anti-parasitic therapies. HDPs are characterised by their small size, amphipathic nature and cationicity, which induce permeabilization of cell membranes, whilst modulating the immune response of the host. Recently, members of the cathelicidin family of HDPs have demonstrated significant antimicrobial activities against various parasites including Leishmania. The cathelicidin bovine myeloid antimicrobial peptide 28 (BMAP-28 has broad antimicrobial activities and confers protection in animal models of bacterial infection or sepsis. We tested the effectiveness of the use of BMAP-28 and two of its isomers the D-amino acid form (D-BMAP-28 and the retro-inverso form (RI-BMAP-28, as anti-leishmanial agents against the promastigote and amastigote intracellular Leishmania major lifecycle stages.An MTS viability assay was utilized to show the potent antiparasitic activity of BMAP-28 and its protease resistant isomers against L. major promastigotes in vitro. Cell membrane permeability assays, caspase 3/7, Tunel assays and morphologic studies suggested that this was a late stage apoptotic cell death with early osmotic cell lysis caused by the antimicrobial peptides. Furthermore, BMAP-28 and its isomers demonstrated anti-leishmanial activities against intracellular amastigotes within a macrophage infection model.Interestingly, D-BMAP-28 appears to be the most potent antiparasitic of the three isomers against wild type L. major promastigotes and amastigotes. These exciting results suggest that BMAP-28 and its protease resistant isomers have significant therapeutic potential as novel anti-leishmanials.

  17. Normocyte-binding protein required for human erythrocyte invasion by the zoonotic malaria parasitePlasmodium knowlesi

    KAUST Repository

    Moon, Robert W.; Sharaf, Hazem; Hastings, Claire H.; Ho, Yung Shwen; Nair, Mridul; Rchiad, ‍ Zineb; Knuepfer, Ellen; Ramaprasad, Abhinay; Mohring, Franziska; Amir, Amirah; Yusuf, Noor A.; Hall, Joanna; Almond, Neil; Lau, Yee Ling; Pain, Arnab; Blackman, Michael J.; Holder, Anthony A.

    2016-01-01

    The dominant cause of malaria in Malaysia is now Plasmodium knowlesi, a zoonotic parasite of cynomolgus macaque monkeys found throughout South East Asia. Comparative genomic analysis of parasites adapted to in vitro growth in either cynomolgus or human RBCs identified a genomic deletion that includes the gene encoding normocyte-binding protein Xa (NBPXa) in parasites growing in cynomolgus RBCs but not in human RBCs. Experimental deletion of the NBPXa gene in parasites adapted to growth in human RBCs (which retain the ability to grow in cynomolgus RBCs) restricted them to cynomolgus RBCs, demonstrating that this gene is selectively required for parasite multiplication and growth in human RBCs. NBPXa-null parasites could bind to human RBCs, but invasion of these cells was severely impaired. Therefore, NBPXa is identified as a key mediator of P. knowlesi human infection and may be a target for vaccine development against this emerging pathogen.

  18. Normocyte-binding protein required for human erythrocyte invasion by the zoonotic malaria parasitePlasmodium knowlesi

    KAUST Repository

    Moon, Robert W.

    2016-06-15

    The dominant cause of malaria in Malaysia is now Plasmodium knowlesi, a zoonotic parasite of cynomolgus macaque monkeys found throughout South East Asia. Comparative genomic analysis of parasites adapted to in vitro growth in either cynomolgus or human RBCs identified a genomic deletion that includes the gene encoding normocyte-binding protein Xa (NBPXa) in parasites growing in cynomolgus RBCs but not in human RBCs. Experimental deletion of the NBPXa gene in parasites adapted to growth in human RBCs (which retain the ability to grow in cynomolgus RBCs) restricted them to cynomolgus RBCs, demonstrating that this gene is selectively required for parasite multiplication and growth in human RBCs. NBPXa-null parasites could bind to human RBCs, but invasion of these cells was severely impaired. Therefore, NBPXa is identified as a key mediator of P. knowlesi human infection and may be a target for vaccine development against this emerging pathogen.

  19. Green economic growth premise for sustainable development

    Directory of Open Access Journals (Sweden)

    Carmen Lenuţa TRICĂ

    2013-01-01

    Full Text Available Accelerating the global issues such as natural resource depletion, damage to the natural environment, economic and financial crises and consumption growth led to the shift of the development paradigm from consumption to sustainable development and recognition of the new path, namely green economy.At the European level a number of international organizations discussed issues of transition to green economy (EC, UNEP, OECD. In 2008, UNEP launched “Green Economy Initiative to Get the Global Markets Back to Work”, aiming to mobilize and re-focuse the global economy towards.This is the twin challenge of moving towards a green economy: radically reducing the footprint of developed countries, while simultaneously raising levels of social and material well being in developing countries.Without public intervention, the related market failures (i.e. market prices that do not fully reflect the environmental degradation generated by economic activity may delay or even prevent the development of environmentally-friendly technologies.Furthermore, in sectors such as electricity, network effects arising from existing infrastructures create additional barriers to the adoption of alternative sources of power, further hampering incentives to invest in new technologies.Given that the transition to a green economy requires increasing of investment in economic sectors that contribute to enhancing of natural capital and reduce environmental risks, we intend to analyze the main measures taken by Romania to ensure transition to green economy.

  20. Crescimento micelial e parasitismo de Paecilomyces lilacinus sobre ovos de Meloidogyne paranaensis em diferentes temperaturas"in vitro" "In vitro" mycelial growth and parasitism of Paecilomyces lilacinus on Meloidogyne paranaensis eggs at different temperatures

    Directory of Open Access Journals (Sweden)

    Marina Capparelli Cadioli

    2007-04-01

    Full Text Available Paecilomyces lilacinus é um fungo de solo, parasita facultativo de ovos de nematóides, que pode crescer rapidamente "in vitro". Este trabalho teve como objetivo avaliar o crescimento micelial de P. lilacinus em diferentes temperaturas e selecionar os melhores isolados quanto à capacidade de parasitar ovos de Meloidogyne paranaensis. Foram avaliados isolados de P. lilacinus, obtidos de solos coletados na região de Londrina, PR. Para o isolamento empregou-se a técnica de diluição seriada dos solos e plaqueamento em meio de cultura semi-seletivo. A determinação do crescimento micelial e do parasitismo "in vitro" dos isolados sobre M. paranaensis foi realizada em placas de Petri contendo meio BDA. Os isolados foram incubados em B.O.D. a temperaturas de 20ºC, 22,5ºC, 25ºC, 27,5ºC e 30ºC. A avaliação do crescimento foi interrompida quando em um dos tratamentos a colônia do fungo atingiu a borda da placa de Petri e a determinação do parasitismo foi realizada depois de oito dias de incubação, calculando-se a porcentagem de ovos parasitados. O crescimento micelial dos isolados de P. lilacinus teve grande dependência da temperatura de incubação a que foram submetidos, sendo mais rápido à temperatura de 22,5ºC. Os isolados de P. lilacinus revelaram habilidade para infectar os ovos de M. paranaensis em meio BDA, principalmente na temperatura de 25ºC.Paecilomyces lilacinus is a soil fungus, facultative parasite of nematode eggs, which develops quickly "in vitro". The mycelial growth of P. lilacinus isolates was evaluated at different temperatures and the best isolates, regarding the capacity to parasite Meloidogyne paranaensis eggs, were chosen. P. lilacinus soil isolates from Londrina, Parana state, were evaluated. Isolation was done using serial dilution of the soils and plating it in semi-selective agar medium. The determination of mycelial growth and "in vitro" parasitism of these isolates was done using Petri plates

  1. Transfection of Eimeria mitis with yellow fluorescent protein as reporter and the endogenous development of the transgenic parasite.

    Directory of Open Access Journals (Sweden)

    Mei Qin

    Full Text Available BACKGROUND: Advancements have been made in the genetic manipulation of apicomplexan parasites. Both the in vitro transient and in vivo stable transfection of Eimeria tenella have been developed successfully. Herein, we report the transient and stable transfection of Eimeria mitis. METHODS AND FINDINGS: Sporozoites of E. mitis transfected with enhanced yellow fluorescent protein (EYFP expression plasmid were inoculated into chickens via the cloacal route. The recovered fluorescent oocysts were sorted by fluorescence activated cell sorting (FACS and then passaged 6 generations successively in chickens. The resulting population was analyzed by genome walking and Western blot. The endogenous development of the transgenic E. mitis was observed and its reproduction potential was tested. The stable transfection of E. mitis was developed. Genome walking confirmed the random integration of plasmid DNA into the genome; while Western blot analysis demonstrated the expression of foreign proteins. Constitutive expression of EYFP was observed in all stages of merogony, gametogony and sporogony. The peak of the transgenic oocyst output was delayed by 24 h and the total oocyst reproduction was reduced by 7-fold when compared to the parental strain. CONCLUSION: Stable transfection of E. mitis was successfully developed. The expression of foreign antigens in the transgenic parasites will facilitate the development of transgenic E. mitis as a vaccine vector.

  2. Plasmodium P-Type Cyclin CYC3 Modulates Endomitotic Growth during Oocyst Development in Mosquitoes

    Science.gov (United States)

    Ferguson, David J. P.; Kaindama, Mbinda L.; Brusini, Lorenzo; Joshi, Nimitray; Rchiad, Zineb; Brady, Declan; Guttery, David S.; Wheatley, Sally P.; Yamano, Hiroyuki; Holder, Anthony A.; Pain, Arnab; Wickstead, Bill; Tewari, Rita

    2015-01-01

    Cell-cycle progression and cell division in eukaryotes are governed in part by the cyclin family and their regulation of cyclin-dependent kinases (CDKs). Cyclins are very well characterised in model systems such as yeast and human cells, but surprisingly little is known about their number and role in Plasmodium, the unicellular protozoan parasite that causes malaria. Malaria parasite cell division and proliferation differs from that of many eukaryotes. During its life cycle it undergoes two types of mitosis: endomitosis in asexual stages and an extremely rapid mitotic process during male gametogenesis. Both schizogony (producing merozoites) in host liver and red blood cells, and sporogony (producing sporozoites) in the mosquito vector, are endomitotic with repeated nuclear replication, without chromosome condensation, before cell division. The role of specific cyclins during Plasmodium cell proliferation was unknown. We show here that the Plasmodium genome contains only three cyclin genes, representing an unusual repertoire of cyclin classes. Expression and reverse genetic analyses of the single Plant (P)-type cyclin, CYC3, in the rodent malaria parasite, Plasmodium berghei, revealed a cytoplasmic and nuclear location of the GFP-tagged protein throughout the lifecycle. Deletion of cyc3 resulted in defects in size, number and growth of oocysts, with abnormalities in budding and sporozoite formation. Furthermore, global transcript analysis of the cyc3-deleted and wild type parasites at gametocyte and ookinete stages identified differentially expressed genes required for signalling, invasion and oocyst development. Collectively these data suggest that cyc3 modulates oocyst endomitotic development in Plasmodium berghei. PMID:26565797

  3. Evaluation Of Growth And Development In Mango Fruits Cvs. Julie ...

    African Journals Online (AJOL)

    Evaluation Of Growth And Development In Mango Fruits Cvs. Julie And Peter To Determine Maturity. ... Two mango cultivars viz., Julie and Peter, were studied for growth and development of fruits in 2001 and 2002 ... HOW TO USE AJOL.

  4. ECONOMIC GROWTH – COSTS AND DEVELOPMENT DISCREPANCES

    OpenAIRE

    Ion Bucur

    2007-01-01

    The economic growth shows an ascending tendency of the economic evolution over a long period of time, having favorable social and economic effects. Each economic growth factor acts simultaneous trough three dimensions.

  5. Development of Low Parasitic Light Sensitivity and Low Dark Current 2.8 μm Global Shutter Pixel †

    Science.gov (United States)

    Yokoyama, Toshifumi; Tsutsui, Masafumi; Suzuki, Masakatsu; Nishi, Yoshiaki; Mizuno, Ikuo; Lahav, Assaf

    2018-01-01

    We developed a low parasitic light sensitivity (PLS) and low dark current 2.8 μm global shutter pixel. We propose a new inner lens design concept to realize both low PLS and high quantum efficiency (QE). 1/PLS is 7700 and QE is 62% at a wavelength of 530 nm. We also propose a new storage-gate based memory node for low dark current. P-type implants and negative gate biasing are introduced to suppress dark current at the surface of the memory node. This memory node structure shows the world smallest dark current of 9.5 e−/s at 60 °C. PMID:29370146

  6. De novo assembly and characterization of the transcriptome of the parasitic weed dodder identifies genes associated with plant parasitism.

    Science.gov (United States)

    Ranjan, Aashish; Ichihashi, Yasunori; Farhi, Moran; Zumstein, Kristina; Townsley, Brad; David-Schwartz, Rakefet; Sinha, Neelima R

    2014-11-01

    Parasitic flowering plants are one of the most destructive agricultural pests and have major impact on crop yields throughout the world. Being dependent on finding a host plant for growth, parasitic plants penetrate their host using specialized organs called haustoria. Haustoria establish vascular connections with the host, which enable the parasite to steal nutrients and water. The underlying molecular and developmental basis of parasitism by plants is largely unknown. In order to investigate the process of parasitism, RNAs from different stages (i.e. seed, seedling, vegetative strand, prehaustoria, haustoria, and flower) were used to de novo assemble and annotate the transcriptome of the obligate plant stem parasite dodder (Cuscuta pentagona). The assembled transcriptome was used to dissect transcriptional dynamics during dodder development and parasitism and identified key gene categories involved in the process of plant parasitism. Host plant infection is accompanied by increased expression of parasite genes underlying transport and transporter categories, response to stress and stimuli, as well as genes encoding enzymes involved in cell wall modifications. By contrast, expression of photosynthetic genes is decreased in the dodder infective stages compared with normal stem. In addition, genes relating to biosynthesis, transport, and response of phytohormones, such as auxin, gibberellins, and strigolactone, were differentially expressed in the dodder infective stages compared with stems and seedlings. This analysis sheds light on the transcriptional changes that accompany plant parasitism and will aid in identifying potential gene targets for use in controlling the infestation of crops by parasitic weeds. © 2014 American Society of Plant Biologists. All Rights Reserved.

  7. Vaccine development against the Taenia solium parasite: the role of recombinant protein expression in Escherichia coli.

    Science.gov (United States)

    Gauci, Charles; Jayashi, César; Lightowlers, Marshall W

    2013-01-01

    Taenia solium is a zoonotic parasite that causes cysticercosis. The parasite is a major cause of human disease in impoverished communities where it is transmitted to humans from pigs which act as intermediate hosts. Vaccination of pigs to prevent transmission of T. solium to humans is an approach that has been investigated to control the disease. A recombinant vaccine antigen, TSOL18, has been remarkably successful at reducing infection of pigs with T. solium in several experimental challenge trials. The vaccine has been shown to eliminate transmission of naturally acquired T. solium in a field trial conducted in Africa. We recently reported that the vaccine was also effective in a field trial conducted in Peru. The TSOL18 recombinant antigen for each of these trials has been produced by expression in Escherichia coli. Here we discuss research that has been undertaken on the TSOL18 antigen and related antigens with a focus on improved methods of preparation of recombinant TSOL18 and optimized expression in Escherichia coli.

  8. Maternal androgens in avian brood parasites and their hosts: responses to parasitism and competition?

    Science.gov (United States)

    Hahn, Caldwell; Wingfield, John C.; Fox, David M.; Walker, Brian G.; Thomley, Jill E

    2017-01-01

    In the coevolutionary dynamic of avian brood parasites and their hosts, maternal (or transgenerational) effects have rarely been investigated. We examined the potential role of elevated yolk testosterone in eggs of the principal brood parasite in North America, the brown-headed cowbird, and three of its frequent host species. Elevated maternal androgens in eggs are a common maternal effect observed in many avian species when breeding conditions are unfavorable. These steroids accelerate embryo development, shorten incubation period, increase nestling growth rate, and enhance begging vigor, all traits that can increase the survival of offspring. We hypothesized that elevated maternal androgens in host eggs are a defense against brood parasitism. Our second hypothesis was that elevated maternal androgens in cowbird eggs are a defense against intra-specific competition. For host species, we found that elevated yolk testosterone was correlated with parasitized nests of small species, those whose nest success is most reduced by cowbird parasitism. For cowbirds, we found that elevated yolk testosterone was correlated with eggs in multiply-parasitized nests, which indicate intra-specific competition for nests due to high cowbird density. We propose experimental work to further examine the use of maternal effects by cowbirds and their hosts.

  9. Cryptosporidium parvum infection in SCID mice infected with only one oocyst: qPCR assessment of parasite replication in tissues and development of digestive cancer.

    Directory of Open Access Journals (Sweden)

    Sadia Benamrouz

    Full Text Available Dexamethasone (Dex treated Severe Combined Immunodeficiency (SCID mice were previously described as developing digestive adenocarcinoma after massive infection with Cryptosporidium parvum as soon as 45 days post-infection (P.I.. We aimed to determine the minimum number of oocysts capable of inducing infection and thereby gastrointestinal tumors in this model. Mice were challenged with calibrated oocyst suspensions containing intended doses of: 1, 10, 100 or 10(5 oocysts of C. parvum Iowa strain. All administered doses were infective for animals but increasing the oocyst challenge lead to an increase in mice infectivity (P = 0.01. Oocyst shedding was detected at 7 days P.I. after inoculation with more than 10 oocysts, and after 15 days in mice challenged with one oocyst. In groups challenged with lower inocula, parasite growth phase was significantly higher (P = 0.005 compared to mice inoculated with higher doses. After 45 days P.I. all groups of mice had a mean of oocyst shedding superior to 10,000 oocyst/g of feces. The most impressive observation of this study was the demonstration that C. parvum-induced digestive adenocarcinoma could be caused by infection with low doses of Cryptosporidium, even with only one oocyst: in mice inoculated with low doses, neoplastic lesions were detected as early as 45 days P.I. both in the stomach and ileo-caecal region, and these lesions could evolve in an invasive adenocarcinoma. These findings show a great amplification effect of parasites in mouse tissues after challenge with low doses as confirmed by quantitative PCR. The ability of C. parvum to infect mice with one oocyst and to develop digestive adenocarcinoma suggests that other mammalian species including humans could be also susceptible to this process, especially when they are severely immunocompromised.

  10. Cryptosporidium parvum infection in SCID mice infected with only one oocyst: qPCR assessment of parasite replication in tissues and development of digestive cancer.

    Science.gov (United States)

    Benamrouz, Sadia; Guyot, Karine; Gazzola, Sophie; Mouray, Anthony; Chassat, Thierry; Delaire, Baptiste; Chabé, Magali; Gosset, Pierre; Viscogliosi, Eric; Dei-Cas, Eduardo; Creusy, Colette; Conseil, Valerie; Certad, Gabriela

    2012-01-01

    Dexamethasone (Dex) treated Severe Combined Immunodeficiency (SCID) mice were previously described as developing digestive adenocarcinoma after massive infection with Cryptosporidium parvum as soon as 45 days post-infection (P.I.). We aimed to determine the minimum number of oocysts capable of inducing infection and thereby gastrointestinal tumors in this model. Mice were challenged with calibrated oocyst suspensions containing intended doses of: 1, 10, 100 or 10(5) oocysts of C. parvum Iowa strain. All administered doses were infective for animals but increasing the oocyst challenge lead to an increase in mice infectivity (P = 0.01). Oocyst shedding was detected at 7 days P.I. after inoculation with more than 10 oocysts, and after 15 days in mice challenged with one oocyst. In groups challenged with lower inocula, parasite growth phase was significantly higher (P = 0.005) compared to mice inoculated with higher doses. After 45 days P.I. all groups of mice had a mean of oocyst shedding superior to 10,000 oocyst/g of feces. The most impressive observation of this study was the demonstration that C. parvum-induced digestive adenocarcinoma could be caused by infection with low doses of Cryptosporidium, even with only one oocyst: in mice inoculated with low doses, neoplastic lesions were detected as early as 45 days P.I. both in the stomach and ileo-caecal region, and these lesions could evolve in an invasive adenocarcinoma. These findings show a great amplification effect of parasites in mouse tissues after challenge with low doses as confirmed by quantitative PCR. The ability of C. parvum to infect mice with one oocyst and to develop digestive adenocarcinoma suggests that other mammalian species including humans could be also susceptible to this process, especially when they are severely immunocompromised.

  11. Biodiversity and springtime patterns of egg production and development for parasites of the Chisana Caribou herd, Yukon Territory, Canada

    Directory of Open Access Journals (Sweden)

    Bryanne Hoar

    2009-12-01

    Full Text Available We investigated the biodiversity and springtime patterns of parasite egg/oocyst and larval production from feces and parasite development in the environment for the Chisana caribou herd in the southwest Yukon Territory, Canada from 29 March to 14 June 2006. Fecal samples from 50 adult cows that were housed in a temporary enclosure within the herd’s natural range at Boundary Lake, Yukon Territory were collected and analyzed during 5 sampling periods. A minimum of 6 parasite genera were recovered: eggs of Trichostrongylidae species (most likely Ostertagia gruehneri and Teladorsagia boreoarcticus, Marshallagia sp., Anoplocephalidae cestodes, and Skrjabinema sp.; oocysts of Eimeria spp.; and dorsal-spined first-stage protostrongylid larvae, including Parelaphostrongylus andersoni. Prevalence of Trichostrongylidae spp. eggs in fresh fecals was at or near 100% throughout the sampling period, however, the median intensity increased significantly from 8 to 34 eggs per gram (epg at the peak of calving and then decreased to 12 epg 2 weeks post-calving (P = 2.83e-07. Three plots of feces collected from these animals were established outside of the enclosure on 4 May 2006 and monitored every 10 days to investigate patterns of parasite development under natural conditions. The total number of Trichostrongylidae spp. (eggs + larvae in fecal plots did not change over time, but as the number of larvae increased, egg counts decreased. The presence of other parasite species in the fecal plots remained constant over time. This study is the first to document the parasite diversity for the Chisana caribou herd and to exam¬ine the development and survival of eggs and larvae in feces throughout the spring and early summer. Abstract in Norwegian / Sammendrag: Parasitters artssammensetning og forløp av eggproduksjon og parasittutvikling om våren hos Chisanavillreinen i Yukon, Canada I en periode fra 29. mars til 14. juni 2006 tok vi prøver fra reinmøkk og under

  12. Animal studies on growth and development.

    Science.gov (United States)

    Lerchl, Alexander

    2011-12-01

    Despite the fact that no plausible biological mechanism has yet been identified how electromagnetic fields below recommended exposure limits could negatively affect health of animals or humans, many experiments have been performed in various animal species, mainly mice and rats, to investigate the possible effects on growth and development. While older studies often suffered from sub-optimal exposure conditions, recent investigations, using sophisticated exposure devices and thus preventing thermal effects, have been performed without these limitations. In principle, two types of studies can be addressed: those which have investigated the carcinogenic or co-carcinogenic effects of exposure in developing animals, and those which have been done in developing animals without the focus on carcinogenic or co-carcinogenic effects. In both areas, the vast majority of publications did not show adverse effects. The largest study so far has been done in normal mice which have been chronically exposed to UMTS signals up to 1.3 W/kg SAR, thus 16 times higher than the whole-body exposure limit for humans. Even after four generations, no systematic or dose-dependent alterations in development or fertility could be found, supporting the view that negative effects on humans are very unlikely. Ongoing experiments in our laboratory investigate the effects of head-only exposure in rats (up to 10 W/kg local SAR) which are exposed from 14 days of age daily for 2 h. A battery of behavioral tests is performed in young, adult, and pre-senile animals. The results will help to clarify possible effects of exposure on brain development. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Does globalization contribute to economic growth in developing ...

    African Journals Online (AJOL)

    This paper examines empirically whether or not globalization contributes to economic growth in developing countries, drawing empirical lessons from Nigeria. The globalization – growth link, is anchored on Husain Schematic representation, Solow model, and the new growth (endogenous growth) theory. The paper adopts ...

  14. Testicular growth and development in puberty.

    Science.gov (United States)

    Koskenniemi, Jaakko J; Virtanen, Helena E; Toppari, Jorma

    2017-06-01

    To describe pubertal testicular growth in humans, changes in testicular cell populations that result in testicular growth, and the role of testosterone and gonadotrophins follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in testicular growth. When human data were not available, studies in nonhuman primates and/or rodents were used as surrogates. Testicular growth in puberty follows a sigmoidal growth curve, with a large variation in timing of testicular growth and adult testicular volume. Testicular growth early in puberty is due to increase in Sertoli cell number and length of seminiferous tubules, whereas the largest and fastest growth results from the increase in the diameter of the seminiferous tubules first due to spermatogonial proliferation and then due to the expansion of meiotic and haploid germ cells. FSH stimulates Sertoli cell and spermatogonial proliferation, whereas LH/testosterone is mandatory to complete spermatogenesis. However, FSH and LH/testosterone work in synergy and are both needed for normal spermatogenesis. Testicular growth during puberty is rapid, and mostly due to germ cell expansion and growth in seminiferous tubule diameter triggered by androgens. Pre-treatment with FSH before the induction of puberty may improve the treatment of hypogonadotropic hypogonadism, but remains to be proven.

  15. Interspecific RNA interference of SHOOT MERISTEMLESS-like disrupts Cuscuta pentagona plant parasitism.

    Science.gov (United States)

    Alakonya, Amos; Kumar, Ravi; Koenig, Daniel; Kimura, Seisuke; Townsley, Brad; Runo, Steven; Garces, Helena M; Kang, Julie; Yanez, Andrea; David-Schwartz, Rakefet; Machuka, Jesse; Sinha, Neelima

    2012-07-01

    Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA-mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection.

  16. Structural analysis of malaria-parasite lysyl-tRNA synthetase provides a platform for drug development.

    Science.gov (United States)

    Khan, Sameena; Garg, Ankur; Camacho, Noelia; Van Rooyen, Jason; Kumar Pole, Anil; Belrhali, Hassan; Ribas de Pouplana, Lluis; Sharma, Vinay; Sharma, Amit

    2013-05-01

    Aminoacyl-tRNA synthetases are essential enzymes that transmit information from the genetic code to proteins in cells and are targets for antipathogen drug development. Elucidation of the crystal structure of cytoplasmic lysyl-tRNA synthetase from the malaria parasite Plasmodium falciparum (PfLysRS) has allowed direct comparison with human LysRS. The authors' data suggest that PfLysRS is dimeric in solution, whereas the human counterpart can also adopt tetrameric forms. It is shown for the first time that PfLysRS is capable of synthesizing the signalling molecule Ap4a (diadenosine tetraphosphate) using ATP as a substrate. The PfLysRS crystal structure is in the apo form, such that binding to ATP will require rotameric changes in four conserved residues. Differences in the active-site regions of parasite and human LysRSs suggest the possibility of exploiting PfLysRS for selective inhibition. These investigations on PfLysRS further validate malarial LysRSs as attractive antimalarial targets and provide new structural space for the development of inhibitors that target pathogen LysRSs selectively.

  17. Plasmodium chabaudi chabaudi malaria parasites can develop stable resistance to atovaquone with a mutation in the cytochrome b gene

    Directory of Open Access Journals (Sweden)

    Alves Ana C

    2010-05-01

    Full Text Available Abstract Background Plasmodium falciparum, has developed resistance to many of the drugs in use. The recommended treatment policy is now to use drug combinations. The atovaquone-proguanil (AP drug combination, is one of the treatment and prophylaxis options. Atovaquone (ATQ exerts its action by inhibiting plasmodial mitochondria electron transport at the level of the cytochrome bc1 complex. Plasmodium falciparum in vitro resistance to ATQ has been associated with specific point mutations in the region spanning codons 271-284 of the cytochrome b gene. ATQ -resistant Plasmodium yoelii and Plasmodium berghei lines have been obtained and resistant lines have amino acid mutations in their CYT b protein sequences. Plasmodium chabaudi model for studying drug-responses and drug-resistance selection is a very useful rodent malaria model but no ATQ resistant parasites have been reported so far. The aim of this study was to determine the ATQ sensitivity of the P. chabaudi clones, to select a resistant parasite line and to perform genotypic characterization of the cytb gene of these clones. Methods To select for ATQ resistance, Plasmodium. chabaudi chabaudi clones were exposed to gradually increasing concentrations of ATQ during several consecutive passages in mice. Plasmodium chabaudi cytb gene was amplified and sequenced. Results ATQ resistance was selected from the clone AS-3CQ. In order to confirm whether an heritable genetic mutation underlies the response of AS-ATQ to ATQ, the stability of the drug resistance phenotype in this clone was evaluated by measuring drug responses after (i multiple blood passages in the absence of the drug, (ii freeze/thawing of parasites in liquid nitrogen and (iii transmission through a mosquito host, Anopheles stephensi. ATQ resistance phenotype of the drug-selected parasite clone kept unaltered. Therefore, ATQ resistance in clone AS-ATQ is genetically encoded. The Minimum Curative Dose of AS-ATQ showed a six

  18. Do Technological Developments and Financial Development Promote Economic Growth: Fresh Evidence from Romania

    OpenAIRE

    Ur Rehman, Ijaz; Shahbaz, Muhammad; Kyophilavong, Phouphet

    2013-01-01

    We study the relationship between financial development, technological development and economic growth in Romania. We construct aggregate indices of financial development and technological development using principal component analysis. The ARDL bounds testing approach shows the presence of cointegration between financial development, technological development and economic growth. Financial development and technological development contribute to economic growth. Moreover, financial developmen...

  19. Growth

    Science.gov (United States)

    John R. Jones; George A. Schier

    1985-01-01

    This chapter considers aspen growth as a process, and discusses some characteristics of the growth and development of trees and stands. For the most part, factors affecting growth are discussed elsewhere, particularly in the GENETICS AND VARIATION chapter and in chapters in PART 11. ECOLOGY. Aspen growth as it relates to wood production is examined in the WOOD RESOURCE...

  20. Description of the first cryptic avian malaria parasite, Plasmodium homocircumflexum n. sp., with experimental data on its virulence and development in avian hosts and mosquitoes.

    Science.gov (United States)

    Palinauskas, Vaidas; Žiegytė, Rita; Ilgūnas, Mikas; Iezhova, Tatjana A; Bernotienė, Rasa; Bolshakov, Casimir; Valkiūnas, Gediminas

    2015-01-01

    For over 100 years studies on avian haemosporidian parasite species have relied on similarities in their morphology to establish a species concept. Some exceptional cases have also included information about the life cycle and sporogonic development. More than 50 avian Plasmodium spp. have now been described. However, PCR-based studies show a much broader diversity of haemosporidian parasites, indicating the possible existence of a diverse group of cryptic species. In the present study, using both similarity and phylogenetic species definition concepts, we believe that we report the first characterised cryptic speciation case of an avian Plasmodium parasite. We used sequence information on the mitochondrial cytochrome b gene and constructed phylogenies of identified Plasmodium spp. to define their position in the phylogenetic tree. After analysis of blood stages, the morphology of the parasite was shown to be identical to Plasmodium circumflexum. However, the geographic distribution of the new parasite, the phylogenetic information, as well as patterns of development of infection, indicate that this parasite differs from P. circumflexum. Plasmodium homocircumflexum n. sp. was described based on information about genetic differences from described lineages, phylogenetic position and biological characters. This parasite develops parasitemia in experimentally infected birds - the domestic canary Serinus canaria domestica, siskin Carduelis spinus and crossbill Loxia curvirostra. Anaemia caused by high parasitemia, as well as cerebral paralysis caused by exoerythrocytic stages in the brain, are the main reasons for mortality. Exoerythrocytic stages also form in other organs (heart, kidneys, liver, lungs, spleen, intestines and pectoral muscles). DNA amplification was unsuccessful from faecal samples of heavily infected birds. The sporogonic development initiates, but is abortive, at the oocyst stage in two common European mosquito species, Culex pipiens pipiens (forms

  1. Attracting Foreign Direct Investment for Growth and Development in ...

    African Journals Online (AJOL)

    Foreign Direct Investment (FDI) plays an important role in fostering economic growth ... growth and development efforts, it also brings with it skills and new technology. ... Malaysia, Thailand and China, FDI inflows into sub-Saharan Africa pale.

  2. Clinical chemistry since 1800: growth and development.

    Science.gov (United States)

    Rosenfeld, Louis

    2002-01-01

    The 19th and 20th centuries witnessed the growth and development of clinical chemistry. Many of the individuals and the significance of their contributions are not very well known, especially to new members of the profession. This survey should help familiarize them with the names and significance of the contributions of physicians and chemists such as Fourcroy, Berzelius, Liebig, Prout, Bright, and Rees. Folin and Van Slyke are better known, and it was their work near the end of the second decade of the 20th century that brought the clinical chemist out of the annex of the mortuary and into close relationship with the patient at the bedside. However, the impact on clinical chemistry and the practice of medicine by the 1910 exposé written by Abraham Flexner is not as well known as it deserves to be, nor is the impetus that World War I gave to the spread of laboratory medicine generally known. In the closing decades of the 20th century, automated devices produced an overabundance, and an overuse and misuse, of testing to the detriment of careful history taking and bedside examination of the patient. This is attributable in part to a fascination with machine-produced data. There was also an increased awareness of the value of chemical methods of diagnosis and the need to bring clinician and clinical chemist into a closer partnership. Clinical chemists were urged to develop services into dynamic descriptions of the diagnostic values of laboratory results and to identify medical relevance in interpreting significance for the clinician.

  3. Definition of the complete Schistosoma mansoni hemoglobinase mRNA sequence and gene expression in developing parasites.

    Science.gov (United States)

    el Meanawy, M A; Aji, T; Phillips, N F; Davis, R E; Salata, R A; Malhotra, I; McClain, D; Aikawa, M; Davis, A H

    1990-07-01

    Schistosoma mansoni uses a variety of proteases termed hemoglobinases to obtain nutrition from host globin. Previous reports have characterized cDNAs encoding 1 of these enzymes. However, these sequences did not define the primary structures of the mRNA and protein. The complete sequence of the 1390 base mRNA has now been determined. It encodes a 50 kDa primary translation product. In vitro translations coupled with immunoprecipitations and Western blots of parasite lysates allowed visualization of the 50 kDa form. Production of the 31 kDa mature hemoglobinase from the 50 kDa species involves removal of both NH2 and COOH terminal residues from the primary translation product. Expression of hemoglobinase mRNA and protein was examined during larval parasite development. Low levels were observed in young schistosomula. After 6-9 days in culture, high hemoglobinase levels were seen which correlated with the onset of red blood cell feeding. Immunoelectron microscopy was employed to examine hemoglobinase location and function. In adult worms the enzyme was associated with the gut lumen and gut epithelium. In cercariae, the protease was observed in the head gland, suggesting new roles for the protease.

  4. Population Growth and Poverty in the Developing World.

    Science.gov (United States)

    Birdsall, Nancy

    1980-01-01

    The link between rapid population growth and the absolute poverty which currently afflicts 780 million people in developing countries (excluding China and other centrally planned economies) is examined. As a result of rapid population growth, many countries suffer slow per capita income growth, a lack of progress in reducing income inequality, and…

  5. The evolution of development of vascular cambia and secondary growth

    Science.gov (United States)

    Andrew Groover; Rachel Spicer

    2010-01-01

    Secondary growth from vascular cambia results in radial, woody growth of stems. The innovation of secondary vascular development during plant evolution allowed the production of novel plant forms ranging from massive forest trees to flexible, woody lianas. We present examples of the extensive phylogenetic variation in secondary vascular growth and discuss current...

  6. Development of Low Parasitic Light Sensitivity and Low Dark Current 2.8 μm Global Shutter Pixel

    Directory of Open Access Journals (Sweden)

    Toshifumi Yokoyama

    2018-01-01

    Full Text Available Abstract: We developed a low parasitic light sensitivity (PLS and low dark current 2.8 μm global shutter pixel. We propose a new inner lens design concept to realize both low PLS and high quantum efficiency (QE. 1/PLS is 7700 and QE is 62% at a wavelength of 530 nm. We also propose a new storage-gate based memory node for low dark current. P-type implants and negative gate biasing are introduced to suppress dark current at the surface of the memory node. This memory node structure shows the world smallest dark current of 9.5 e−/s at 60 °C.

  7. The Development and Evaluation of a Teleprocessed Computer-Assisted Instruction Course in the Recognition of Malarial Parasites. Final Report; May 1, 1967 - June 30, 1968.

    Science.gov (United States)

    Mitzel, Harold E.

    A computer-assisted instruction course in the recognition of malarial parasites was developed and evaluated. The course includes stage discrimination, species discrimination, and case histories. Segments developed use COURSEWRITER as an author language and are presented via a display terminal that permits two-way communication with an IBM computer…

  8. Parasitic Apologies

    Science.gov (United States)

    Galatolo, Renata; Ursi, Biagio; Bongelli, Ramona

    2016-01-01

    The action of apologizing can be accomplished as the main business of the interaction or incidentally while participants are doing something else. We refer to these apologies as "parasitic apologies," because they are produced "en passant" (Schegloff, 2007), and focus our analysis on this type of apology occurring at the…

  9. Development and application of an eDNA method to detect and quantify a pathogenic parasite in aquatic ecosystems.

    Science.gov (United States)

    Huver, J R; Koprivnikar, J; Johnson, P T J; Whyard, S

    2015-06-01

    Approaches based on organismal DNA found in the environment (eDNA) have become increasingly utilized for ecological studies and biodiversity inventories as an alternative to traditional field survey methods. Such DNA-based techniques have largely been used to establish the presence of free-living organisms, but have much potential for detecting and quantifying infectious agents in the environment, which is necessary to evaluate disease risk. We developed an eDNA method to examine the distribution and abundance of the trematode Ribeiroia ondatrae, a pathogenic parasite known to cause malformations in North American amphibians. In addition to comparing this eDNA approach to classical host necropsy, we examined the detectability of R. ondatrae in water samples subject to different degradation conditions (time and temperature). Our test exhibited high specificity and sensitivity to R. ondatrae, capable of detecting as little as 14 fg (femtograms) of this parasite's DNA (1/2500th of a single infectious stage) from field water samples. Compared to our results from amphibian host necropsy, quantitative PCR was -90% concordant with respect to R. ondatrae detection from 15 field sites and was also a significant predictor of host infection abundance. DNA was still detectable in lab samples after 21 days at 25°C, indicating that our method is robust to field conditions. By comparing the advantages and disadvantages of eDNA vs. traditional survey methods for determining pathogen presence and abundance in the field, we found that the lower cost and effort associated with eDNA approaches provide many advantages. The development of alternative tools is critical for disease ecology, as wildlife management and conservation efforts require reliable establishment and monitoring of pathogens.

  10. Host modulation by a parasite: how Leishmania infantum modifies the intestinal environment of Lutzomyia longipalpis to favor its development.

    Directory of Open Access Journals (Sweden)

    Vania Cristina Santos

    Full Text Available Some reports have described the interference of Leishmania on sand flies physiology, and such behavior most likely evolved to favor the development and transmission of the parasite. Most of these studies showed that Leishmania could modulate the level of proteases in the midgut after an infective blood meal, and decreased proteolytic activity is indeed beneficial for the development of promastigotes in the gut of sand flies. In the present study, we performed a detailed investigation of the intestinal pH in Lutzomyia longipalpis females naturally infected with Leishmania infantum and investigated the production of trypsin by these insects using different approaches. Our results allowed us to propose a mechanism by which these parasites interfere with the physiology of L. longipalpis to decrease the production of proteolytic enzymes. According to our hypothesis L. infantum promastigotes indirectly interfere with the production of trypsin by modulating the mechanism that controls the intestinal pH via the action of a yet non-identified substance released by promastigote forms inside the midgut. This substance is not an acid, whose action would be restrict on to release H+ to the medium, but is a substance that is able to interfere with midgut physiology through a mechanism involving pH control. According to our hypothesis, as the pH decreases, the proteolytic enzymes efficiency is also reduced, leading to a decline in the supply of amino acids to the enterocytes: this decline reduces the stimulus for protease production because it is regulated by the supply of amino acids, thus leading to a delay in digestion.

  11. Growth and development and their environmental and biological determinants

    Directory of Open Access Journals (Sweden)

    Kelly da Rocha Neves

    2016-05-01

    Conclusion: The results showed a high prevalence of stunting and below‐average results for cognitive/language development among the participating children. Both environmental and biological factors were related to growth and development. However, biological variables showed a greater association with growth, whereas environmental variables were associated with development.

  12. BANKING SECTOR DEVELOPMENT AND ECONOMIC GROWTH INPALESTINE; 1995-2014

    Directory of Open Access Journals (Sweden)

    Gaber H. Abugamea

    2016-07-01

    Full Text Available This study uses both OLS regression estimation and Granger Causality test toinvestigate the relationship between the banking sector development andeconomic growth in Palestine over the period 1995-2014.OLS results show asignificant impact of banking size with a negative sign, insignificant impact ofcredit lending with a marginal one for lag credit andinsignificant impact ofefficiency on economic growth, respectively.Granger Causality testresultsshowone way causality runningfrom banking size to(GDPeconomic growthandfrom banking efficiency to(GDP per capitaeconomic growth one. Overall resultsreveals a weak nexus between banking sector development and economic growth.In specific, it recommends more improving in banking lending policy to beeffective in promoting economic growth.

  13. Cultivation of parasitic leptospires: effect of pyruvate.

    Science.gov (United States)

    Johnson, R C; Walby, J; Henry, R A; Auran, N E

    1973-07-01

    Sodium pyruvate (100 mug/ml) is a useful addition to the Tween 80-albumin medium for the cultivation of parasitic serotypes. It is most effective in promoting growth from small inocula and growth of the nutritionally fastidious serotypes.

  14. Employment and Growth | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Our investments increase employment and economic opportunities for women and youth. ... The Employment and Growth program seeks to enhance the employment and economic opportunities of ... The untold story: IDRC supported researchers transform economic policy in Africa ... Careers · Contact Us · Site map.

  15. THE EVOLUTION OF PARASITES FROM THEIR HOSTS: A CASE STUDY IN THE PARASITIC RED ALGAE.

    Science.gov (United States)

    Goff, Lynda J; Ashen, Jon; Moon, Debra

    1997-08-01

    Morphological similarities of many parasites and their hosts have led to speculation that some groups of plant, animal, fungal, and algal parasites may have evolved directly from their hosts. These parasites, which have been termed adelphoparasites in the botanical literature, and more recently, agastoparasites in the insect literature, may evolve monophyletically from one host and radiate secondarily to other hosts or, these parasites may arise polyphyletically, each arising from its own host. In this study we compare the internal transcribed spacer regions of the nuclear ribosomal repeats of species and formae specialis (host races) included in the red algal parasite genus Asterocolax with its hosts, which all belong to the Phycodrys group of the Delesseriaceae and with closely related nonhost taxa of the Delesseriaceae. These analyses reveal that species of Asterocolax have evolved polyphyletically. Asterocolax erythroglossi from the North Atlantic host Erythroglossum laciniatum appears to have evolved from its host, whereas taxa included in the north Pacific species Asterocolax gardneri have had two independent origins. Asterocolax gardneri from the host Polyneura latissima probably arose directly from this host. In contrast, all other A. gardneri formae specialis appear to have originated from either Phycodrys setchellii or P. isabelliae and radiated secondarily onto other closely related taxa of the Phycodrys group, including Nienburgia andersoniana and Anisocladella pacifica. Gamete crossing experiments confirm that A. gardneri from each host is genetically isolated from both its host, and from other A. gardneri and their hosts. Cross-infection experiments reveal that A. gardneri develops normally only on its natural host, although some abberrant growth may occur on alternate hosts. The ability of red algal parasites to radiate secondarily to other red algal taxa, where they may become isolated genetically and speciate, suggests that this process of

  16. Analysing growth and development of plants jointly using developmental growth stages.

    Science.gov (United States)

    Dambreville, Anaëlle; Lauri, Pierre-Éric; Normand, Frédéric; Guédon, Yann

    2015-01-01

    Plant growth, the increase of organ dimensions over time, and development, the change in plant structure, are often studied as two separate processes. However, there is structural and functional evidence that these two processes are strongly related. The aim of this study was to investigate the co-ordination between growth and development using mango trees, which have well-defined developmental stages. Developmental stages, determined in an expert way, and organ sizes, determined from objective measurements, were collected during the vegetative growth and flowering phases of two cultivars of mango, Mangifera indica. For a given cultivar and growth unit type (either vegetative or flowering), a multistage model based on absolute growth rate sequences deduced from the measurements was first built, and then growth stages deduced from the model were compared with developmental stages. Strong matches were obtained between growth stages and developmental stages, leading to a consistent definition of integrative developmental growth stages. The growth stages highlighted growth asynchronisms between two topologically connected organs, namely the vegetative axis and its leaves. Integrative developmental growth stages emphasize that developmental stages are closely related to organ growth rates. The results are discussed in terms of the possible physiological processes underlying these stages, including plant hydraulics, biomechanics and carbohydrate partitioning. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Development of Technology Transfer Economic Growth Metrics

    Science.gov (United States)

    Mastrangelo, Christina M.

    1998-01-01

    The primary objective of this project is to determine the feasibility of producing technology transfer metrics that answer the question: Do NASA/MSFC technical assistance activities impact economic growth? The data for this project resides in a 7800-record database maintained by Tec-Masters, Incorporated. The technology assistance data results from survey responses from companies and individuals who have interacted with NASA via a Technology Transfer Agreement, or TTA. The goal of this project was to determine if the existing data could provide indications of increased wealth. This work demonstrates that there is evidence that companies that used NASA technology transfer have a higher job growth rate than the rest of the economy. It also shows that the jobs being supported are jobs in higher wage SIC codes, and this indicates improvements in personal wealth. Finally, this work suggests that with correct data, the wealth issue may be addressed.

  18. In vitro Plasmodium falciparum drug sensitivity assay: inhibition of parasite growth by incorporation of stomatocytogenic amphiphiles into the erythrocyte membrane

    DEFF Research Database (Denmark)

    Ziegler, Hanne L; Staerk, Dan; Christensen, Jette

    2002-01-01

    Lupeol, which shows in vitro inhibitory activity against Plasmodium falciparum 3D7 strain with a 50% inhibitory concentration (IC50) of 27.7 +/- 0.5 microM, was shown to cause a transformation of the human erythrocyte shape toward that of stomatocytes. Good correlation between the IC50 value...... culture continued to grow well in untreated erythrocytes. Thus, the antiplasmodial activity of lupeol appears to be indirect, being due to stomatocytic transformation of the host cell membrane and not to toxic effects via action on a drug target within the parasite. A number of amphiphiles that cause...... for development of new antimalarial drugs, care must be exercised in the interpretation of results of screening of plant extracts and natural product libraries by an in vitro Plasmodium toxicity assay....

  19. Corruption and growth in developing countries

    OpenAIRE

    Lacroix, Jean

    2013-01-01

    Corruption is morally condemnable but what about its economical effect on the efficiency of on economy? Different transmission channels positively and negatively correlated with growth exist. The aim of this work is to catch the overall reality behind this impressively high number of transmission channels. Another task is to show the concrete consequences of corruption on a little economy like Haïti and what could be the consequences of the weaknesses induced by corruption. A presentation of ...

  20. Growth and project finance in the least developed countries

    OpenAIRE

    Lisbeth F. la Cour; Jennifer Müller

    2014-01-01

    This article examines the effects of project finance on economic growth in the least developed countries (LDC). Inspired by the neoclassical growth model we set up an econometric model to estimate the effects of project finance for a sample consisting of 38 of the least developed countries using data from the period 1994-2007. The results of our study suggest, that project finance has a significant positive effect on economic growth and therefore constitute an important source of ...

  1. Factors contributing to the development of anaemia in Plasmodium falciparum malaria: what about drug-resistant parasites?

    DEFF Research Database (Denmark)

    Quashie, Neils Ben; Akanmori, Bartholomew D; Ofori-Adjei, David

    2006-01-01

    implicated in its pathogenesis. Since resolution of malaria restores erythropoiesis, we hypothesized that drug-resistant strains of Plasmodium falciparum would increase the risk of severe anaemia developing from initially uncomplicated malaria. Using both in vivo and in vitro drug-sensitivity tests we...... compared the prevalence of drug-resistant malaria between severe malarial anaemia SA and non-anaemic malaria NAM patients. Assessment of treatment outcome using the WHO in vivo criteria showed no significant difference in parasite resistance between the two groups. The mean parasite clearance time was also......-treatment blood levels of chloroquine did not differ much between the two groups. Findings from this study could not therefore implicate drug-resistant parasites in the pathogenesis of severe malarial anaemia....

  2. Uncertainty, financial development and economic growth : an empirical analysis

    NARCIS (Netherlands)

    Lensink, Robert

    1999-01-01

    This paper examines whether financial sector development may partly undo growth-reducing effects of policy uncertainty. By performing a cross-country growth regression for the 1970-1995 period I find evidence that countries with a more developed financial sector are better able to nullify the

  3. Wealth, welfare and sustainable growth and development

    Energy Technology Data Exchange (ETDEWEB)

    Moe, Thorvald

    2011-07-01

    This Policy Note discuses, based on modern development theory and wealth accounting, challenges for economic- and fiscal policies in resource-producing countries defined as countries - both developed and developing low income countries - which rely heavily on non-renewable or exhaustible natural wealth.(Author)

  4. Financing Human Development for Sectorial Growth: A Time Series Analysis

    Directory of Open Access Journals (Sweden)

    Shobande Abdul Olatunji

    2017-06-01

    Full Text Available The role which financing human development plays in fostering the sectorial growth of an economy cannot be undermined. It is a key instrument which can be utilized to alleviate poverty, create employment and ensure the sustenance of economic growth and development. Thus financing human development for sectorial growth has taken the center stage of economic growth and development strategies in most countries. In a constructive effort to examine the in-depth relationship between the variables in the Nigerian space, this paper provides evidence on the impact of financing human development and sectorial growth in Nigeria between 1982 and 2016, using the Johansen co-integration techniques to test for co-integration among the variables and the Vector Error Correction Model (VECM to ascertain the speed of adjustment of the variables to their long run equilibrium position. The analysis shows that a long and short run relationship exists between financing human capital development and sectorial growth during the period reviewed. Therefore, the paper argues that for an active foundation for sustainable sectorial growth and development, financing human capital development across each unit is urgently required through increased budgetary allocation for both health and educational sectors since they are key components of human capital development in a nation.

  5. Interspecific RNA Interference of SHOOT MERISTEMLESS-Like Disrupts Cuscuta pentagona Plant Parasitism[C][W][OA

    Science.gov (United States)

    Alakonya, Amos; Kumar, Ravi; Koenig, Daniel; Kimura, Seisuke; Townsley, Brad; Runo, Steven; Garces, Helena M.; Kang, Julie; Yanez, Andrea; David-Schwartz, Rakefet; Machuka, Jesse; Sinha, Neelima

    2012-01-01

    Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA–mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection. PMID:22822208

  6. Growth and development studies Hiroshima and Nagasaki: research plan

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S C; Jablon, S; Hrubec, Zdenek

    1962-03-21

    This report summarizes the research plan for prospective evaluation of growth and development in those exposed to varying amounts of ionizing radiation during childhood or while in utero in Hiroshima or Nagasaki. Some experimental observations are briefly presented to provide background information, and the results of previous studies of growth and development at the Atomic Bomb Casualty Commission (ABCC) are reviewed. Procedures have been described for determining the top of the growth curve for the in utero exposed and the maximum growth and development of those exposed during childhood in comparison to their nonexposed counterparts. Differences in growth and development found between exposed and nonexposed individuals will be analysed in relation to radiation dose, age at time of exposure, sex, and socioeconomic factors. Attempts will be made to determine whether or not abnormalities in visual acuity are increased in those exposed while in utero or during childhood as compared to nonexposed or comparable ages. 23 references, 2 tables.

  7. Past Intestinal Parasites.

    Science.gov (United States)

    Le Bailly, Matthieu; Araújo, Adauto

    2016-08-01

    This chapter aims to provide some key points for researchers interested in the study of ancient gastrointestinal parasites. These few pages are dedicated to my colleague and friend, Prof. Adauto Araújo (1951-2015), who participated in the writing of this chapter. His huge efforts in paleoparasitology contributed to the development and promotion of the discipline during more than 30 years.

  8. Trophic structure of arthropods in Starling nests matter to blood parasites and thereby to nestling development

    NARCIS (Netherlands)

    Wolfs, Peter H. J.; Lesna, Izabela K.; Sabelis, Maurice W.; Komdeur, Jan; Bairlein, F.

    Nestling development and long-term survival in many bird species depend on factors such as parental feeding, time of breeding and environmental conditions. However, little research has been carried out on the effect of ectoparasites on nestling development, and no research on the impact of the

  9. Trophic structure of arthropods in Starling nests matter to blood parasites and thereby to nestling development

    NARCIS (Netherlands)

    Wolfs, P.H.J.; Lesna, I.K.; Sabelis, M.W.; Komdeur, J.

    2012-01-01

    Nestling development and long-term survival in many bird species depend on factors such as parental feeding, time of breeding and environmental conditions. However, little research has been carried out on the effect of ectoparasites on nestling development, and no research on the impact of the

  10. Worker remittances, migration, accumulation and growth in poor developing countries

    OpenAIRE

    Ziesemer, T.H.W.

    2008-01-01

    The impact of migration and worker remittances on literacy, accumulation of capital and growth is analyzed for a panel of countries with per capita income below $1200 (2000). We estimate regressions for dynamic equations of migration, worker remittances, savings, investment, tax revenues, public expenditure on education, interest rates, literacy, labour force growth, development aid and GDP per capita growth, using dynamic panel data methods. The estimated equations are then integrated to a d...

  11. Protozoan Parasites in Drinking Water: A System Approach for Improved Water, Sanitation and Hygiene in Developing Countries.

    Science.gov (United States)

    Omarova, Alua; Tussupova, Kamshat; Berndtsson, Ronny; Kalishev, Marat; Sharapatova, Kulyash

    2018-03-12

    Improved water, sanitation and hygiene (WASH) are significant in preventing diarrhea morbidity and mortality caused by protozoa in low- and middle-income countries. Due to the intimate and complex relationships between the different WASH components, it is often necessary to improve not just one but all of these components to have sustainable results. The objective of this paper was to review the current state of WASH-related health problems caused by parasitic protozoa by: giving an overview and classification of protozoa and their effect on people's health, discussing different ways to improve accessibility to safe drinking water, sanitation services and personal hygiene behavior; and suggesting an institutional approach to ensure improved WASH. The findings indicate that Giardia and Cryptosporidium are more often identified during waterborne or water-washed outbreaks and they are less sensitive than most of the bacteria and viruses to conventional drinking water and wastewater treatment methods. There are various institutions of control and prevention of water-related diseases caused by protozoa in developed countries. Unfortunately, the developing regions do not have comparable systems. Consequently, the institutional and systems approach to WASH is necessary in these countries.

  12. Protozoan Parasites in Drinking Water: A System Approach for Improved Water, Sanitation and Hygiene in Developing Countries

    Science.gov (United States)

    Tussupova, Kamshat; Berndtsson, Ronny; Sharapatova, Kulyash

    2018-01-01

    Improved water, sanitation and hygiene (WASH) are significant in preventing diarrhea morbidity and mortality caused by protozoa in low- and middle-income countries. Due to the intimate and complex relationships between the different WASH components, it is often necessary to improve not just one but all of these components to have sustainable results. The objective of this paper was to review the current state of WASH-related health problems caused by parasitic protozoa by: giving an overview and classification of protozoa and their effect on people’s health, discussing different ways to improve accessibility to safe drinking water, sanitation services and personal hygiene behavior; and suggesting an institutional approach to ensure improved WASH. The findings indicate that Giardia and Cryptosporidium are more often identified during waterborne or water-washed outbreaks and they are less sensitive than most of the bacteria and viruses to conventional drinking water and wastewater treatment methods. There are various institutions of control and prevention of water-related diseases caused by protozoa in developed countries. Unfortunately, the developing regions do not have comparable systems. Consequently, the institutional and systems approach to WASH is necessary in these countries. PMID:29534511

  13. Protozoan Parasites in Drinking Water: A System Approach for Improved Water, Sanitation and Hygiene in Developing Countries

    Directory of Open Access Journals (Sweden)

    Alua Omarova

    2018-03-01

    Full Text Available Improved water, sanitation and hygiene (WASH are significant in preventing diarrhea morbidity and mortality caused by protozoa in low- and middle-income countries. Due to the intimate and complex relationships between the different WASH components, it is often necessary to improve not just one but all of these components to have sustainable results. The objective of this paper was to review the current state of WASH-related health problems caused by parasitic protozoa by: giving an overview and classification of protozoa and their effect on people’s health, discussing different ways to improve accessibility to safe drinking water, sanitation services and personal hygiene behavior; and suggesting an institutional approach to ensure improved WASH. The findings indicate that Giardia and Cryptosporidium are more often identified during waterborne or water-washed outbreaks and they are less sensitive than most of the bacteria and viruses to conventional drinking water and wastewater treatment methods. There are various institutions of control and prevention of water-related diseases caused by protozoa in developed countries. Unfortunately, the developing regions do not have comparable systems. Consequently, the institutional and systems approach to WASH is necessary in these countries.

  14. Solar Energy - It's Growth, Development, and Use

    Science.gov (United States)

    dropdown arrow Site Map A-Z Index Menu Synopsis Solar Energy Resources with Additional Information Solar has played a major role in solar energy development through previous research and ongoing activities . As a result of research and development, the "cost of solar energy has been reduced 100-fold

  15. Growth and development after hematopoietic cell transplant in children.

    Science.gov (United States)

    Sanders, J E

    2008-01-01

    Hematopoietic cell transplantation (HCT) following high-dose chemotherapy or chemoradiotherapy for children with malignant or nonmalignant hematologic disorders has resulted in an increasing number of long-term disease-free survivors. The preparative regimens include high doses of alkylating agents, such as CY with or without BU, and may include TBI. These agents impact the neuroendocrine system in growing children and their subsequent growth and development. Children receiving high-dose CY or BUCY have normal thyroid function, but those who receive TBI-containing regimens may develop thyroid function abnormalities. Growth is not impacted by chemotherapy-only preparative regimens, but TBI is likely to result in growth hormone deficiency and decreased growth rates that need to be treated with synthetic growth hormone therapy. Children who receive high-dose CY-only have normal development through puberty, whereas those who receive BUCY have a high incidence of delayed pubertal development. Following fractionated TBI preparative regimens, approximately half of the patients have normal pubertal development. These data demonstrate that the growth and development problems after HCT are dependent upon the preparative regimen received. All children should be followed for years after HCT for detection of growth and development abnormalities that are treatable with appropriate hormone therapy.

  16. Why higher economic growth cannot always enhance human development

    OpenAIRE

    Ahmed, Md Montasir

    2017-01-01

    This paper studies why higher economic growth cannot always enhance human development. In general, these two dimensions have a strong and positive relationship, but some countries appear unable to balance this relationship. As a consequence, there are some countries with high economic growth but sluggish human development progress. This paper studies how other factors besides GDP – women labor force participation, urbanization, and inequality - are correlated to human development. I construct...

  17. Development of anti-infectives using phage display: biological agents against bacteria, viruses, and parasites.

    Science.gov (United States)

    Huang, Johnny X; Bishop-Hurley, Sharon L; Cooper, Matthew A

    2012-09-01

    The vast majority of anti-infective therapeutics on the market or in development are small molecules; however, there is now a nascent pipeline of biological agents in development. Until recently, phage display technologies were used mainly to produce monoclonal antibodies (MAbs) targeted against cancer or inflammatory disease targets. Patent disputes impeded broad use of these methods and contributed to the dearth of candidates in the clinic during the 1990s. Today, however, phage display is recognized as a powerful tool for selecting novel peptides and antibodies that can bind to a wide range of antigens, ranging from whole cells to proteins and lipid targets. In this review, we highlight research that exploits phage display technology as a means of discovering novel therapeutics against infectious diseases, with a focus on antimicrobial peptides and antibodies in clinical or preclinical development. We discuss the different strategies and methods used to derive, select, and develop anti-infectives from phage display libraries and then highlight case studies of drug candidates in the process of development and commercialization. Advances in screening, manufacturing, and humanization technologies now mean that phage display can make a significant contribution in the fight against clinically important pathogens.

  18. Irradiation growth of Zircaloy (LWBR) development program

    International Nuclear Information System (INIS)

    Williard, H.J.

    1984-01-01

    Irradiation growth of recrystallized annealed (RXA) Zircaloy is divided into four stages and a model is presented to account for each stage. Stage I is a short time, low-strain transient caused by the accumulation of point defects, small interstitial loops, and vacancy clusters. Stage II is a quasi-steady-state region of relatively low strain rate during which the loops grow and intrinsic dislocations climb. Stage III is a transient during which the strain rate increases due to the production and motion of irradiation-induced dislocation lines. Stage IV is a high-strain-rate, steady-state region during which nonrecoverable strain is caused predominantly by glide of the irradiationinduced dislocations. The proposed model is based on two new mechanisms: (1) direct production of an interstitial dislocation loop accompanied by a vacancy cluster in the primary damage event, and (2) production of dislocations due to the activation of Frank-Read sources by internal stresses caused by interaction of the loops with themselves and with intrinsic (cold work) dislocations. Nonconservative, recoverable strain is due to climb of all dislocations, whereas conservative, nonrecoverable strain is caused by glide of irradiation-induced and intrinsic dislocations under the action of the internal stress. The conservative strain follows a (1-3f) texture dependence

  19. Networks: Innovation, Growth and Sustainable Development

    Directory of Open Access Journals (Sweden)

    Peter Johnston

    2013-05-01

    Full Text Available The emergence of the Internet as a measureable manifestation of our social and economic relationships changed the domination of networks in our lives. From about 2000, the internet has allowed us to study and understand the type of networks in which we live, and to model their behaviour. The Internet has fundamentally changed the distribution of wealth. The rich became richer simply because of the larger scale of the trading network and stretched national wealth distributions. Network effects are therefore likely to be responsible for much of the perceived increases in inequalities in the last 20-30 years, and policies to tackle poverty must therefore address the extent to which the poor can engage with society's networks of wealth creation. The greatest challenge to continued growth and prosperity, and therefore to peace and justice, is climate change. The potential cost of inaction on climate change could be as high. Our self-organising social networks have structured our societies and economies, and are now reflected in our technology networks. We can now replicate their evolution in computer simulations and can therefore better assess how to deal with the greatest challenges facing us in the next few decades.

  20. International Trade as an Engine of Growth in Developing Countries ...

    African Journals Online (AJOL)

    This study examines international trade as an engine of growth in developing countries, a case study of Nigeria. A review of the literature reveals that countries that are more open to international trade tends to experience higher growth rate and per-capital income than countries who do not trade or closed economy.

  1. Africa's Growth and Development Strategies: A Critical Review ...

    African Journals Online (AJOL)

    At independence in the late 1950s and early 1960s, there were high hopes about the growth prospects of the new politically independent. African states. Economic conditions, such as per capita real income, were comparable to other developing countries like South Korea and. Taiwan. By the mid-1970s, the growth profile ...

  2. Symbiotic regulation of plant growth, development and reproduction

    Science.gov (United States)

    Russell J. Rodriguez; D. Carl Freeman; E. Durant McArthur; Yong Ok Kim; Regina S. Redman

    2009-01-01

    The growth and development of rice (Oryzae sativa) seedlings was shown to be regulated epigenetically by a fungal endophyte. In contrast to un-inoculated (nonsymbiotic) plants, endophyte colonized (symbiotic) plants preferentially allocated resources into root growth until root hairs were well established. During that time symbiotic roots expanded at...

  3. The Use of Twitter for Professional Growth and Development

    Science.gov (United States)

    Gerstein, Jackie

    2011-01-01

    Twitter, the micro blogging tool, has seen unprecedented growth in the past year and is expected to continue into the future. Twitter's power, engagement, and popularity lie in its endless networking opportunities. Its potential as a venue for professional growth and development needs to be explored, discussed, and ultimately used as such. A brief…

  4. How Stock Markets Development Affect Endogenous Growth Theory

    Directory of Open Access Journals (Sweden)

    Najeb Masoud

    2013-10-01

    Full Text Available This paper can bedescribed as a significant exploratory study that will provide a significantcontribution to knowledge to consider crucial issues which need to be barriersto understanding or a temptation/ requirement to judge some practices as‘better’ than others for stock market development effective approach andimplement successful stock market performance and economic growth. Recentanalysis of the link between financial development and growth, gained frominsights acquired as a result of using the technique of endogenous growthmodels, has illustrated that growth without exogenous technical progress andthat growth rates could be related to technology, income distribution andinstitutional arrangements. This provides the theoretical background thatempirical studies have lacked; illustrating that financial intermediationaffects the level of economic growth. Resulting models have provided newimpetus to empirical research of the effects of financial development. Thebirth of the new endogenous growth theory has facilitated the development ofimproved growth models where the long-term rate could be affected by a numberof elements. These included technology, education and health policies in theprocess of economic development, capital accumulation, government policies andinstitutional activities in the role of financial development in economicgrowth.

  5. Remittances, financial development and economic growth: Empirical evidence from Lesotho

    Directory of Open Access Journals (Sweden)

    Athenia Bongani Sibindi

    2014-11-01

    Full Text Available Increasingly remittances now constitute a great source of foreign currency inflows for many developing countries. In some instances remittances have outpaced the growth of foreign direct investment (FDI. Amongst others, remittances can be used as a vehicle of savings mobilisation as well as fostering the supply of credit by providing liquidity to the market. In this article we investigate the causal relationship between the remittances, financial development and economic growth in Lesotho for the period 1975 to 2010. We make use of per capita remittances, real per capita broad money supply and real per capita growth domestic product as the proxies for remittances, financial development and economic growth respectively. We then test for cointegration amongst the variables by applying the Johansen procedure and then test for Granger causality based on the vector error correction model (VECM. Our results confirm the existence of at least one cointegrating relationship and also indicate that the direction of causality runs from remittances to the economy without feedback. The results also suggest that financial development Granger causes economic growth without feedback which is consistent with ‘supply-leading’ growth hypothesis. The results also confirm a causal relationship running from financial development to remittances without feedback. The results also lend credence to the “complementarity’ hypothesis in that, remittances complement rather than substitute financial development in bringing about economic growth.

  6. Leptin administration affects growth and skeletal development in a rat intrauterine growth restriction model: preliminary study.

    Science.gov (United States)

    Bar-El Dadon, Shimrit; Shahar, Ron; Katalan, Vered; Monsonego-Ornan, Efrat; Reifen, Ram

    2011-09-01

    Skeletal abnormalities are one of the hallmarks of growth delay during gestation. The aim of this study was to determine changes induced by leptin in skeletal growth and development in a rat model of intrauterine growth retardation (IUGR) and to elucidate the possible underlying mechanisms. Intrauterine growth retardation was induced prepartum and the effects of leptin to mothers prenatally or to offspring postnatally were studied. Radii were harvested and tested mechanically and structurally. Tibias were evaluated for growth-plate morphometry. On day 40 postpartum, total bone length and mineral density and tibial growth-plate width and numbers of cells within its zones of offspring treated with leptin were significantly greater than in the control group. Postnatal leptin administration in an IUGR model improves the structural properties and elongation rate of bone. These findings could pave the way to preventing some phenotypic presentations of IUGR. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Developing a Model of Health Behavior Change to Reduce Parasitic Disease in Vietnam

    Science.gov (United States)

    Petersen, Suni; Do, Trina; Shaw, Christy; Brake, Kaile

    2016-01-01

    Worldwide more deaths occur due to conditions that can be ameliorated by behavior change. Changing health behaviors using models popularized in non-western countries has not proven particularly successful. The purpose of this study was to test variables elicited during qualitative interviews and cultural conversations to develop a model of health…

  8. Growth & development of Indian children adopted in Sweden.

    Science.gov (United States)

    Proos, Lemm A

    2009-11-01

    More than 6800 children from India have been adopted in Sweden over the last four decades. At arrival many were undernourished and suffered from infectious diseases. Catch-up growth was common. Unexpectedly, cases of early pubertal development were subsequently reported. In order to investigate the growth and development of adopted children more in detail we studied 114 children adopted from India prospectively during two years. The majority were stunted at arrival and caught up in height and weight after two years. Psychomotor retardation and common infections diminished fairly soon. Those that were stunted did not attain the higher catch-up levels of those not stunted at arrival. Low birthweight also limited the degree of catch-up growth. 107 girls were analysed retrospectively in another study. The median menarcheal age was 11.6 yr (range 7.3-14.6 yr) which is significantly earlier than the mean in Swedish and privileged Indian girls (13.0 and 12.4-12.9 yr, respectively). The pubertal linear growth component was normal in duration and magnitude but likewise started 1.5 yr earlier. The final height/age was 154 cm (-1.4 SDS) and the weight/age 46.9 kg (-1.1 SDS) 8 per cent were 145 cm or shorter. Stunting limited catch-up growth and final height. Those that were most stunted at arrival, and had the fastest catch-up growth, had the earliest menarche. Good maternal and child nutrition is necessary for full expression of a child's growth potential. What is lost in growth early in life can only partially be recovered by catch-up growth. Such growth is associated with risk for early pubertal development which abbreviates the childhood growth period and limits final height. The mechanism underlying the early pubertal development, and the optimal management of nutrition rehabilitation after chronic malnutrition, need to be clarified by further studies.

  9. GROWTH ECONOMICS AND DEVELOPMENT ECONOMICS: WHAT SHOULD DEVELOPMENT ECONOMISTS LEARN (IF ANYTHING) FROM THE NEW GROWTH THEORY?

    OpenAIRE

    Ruttan, Vernon W.

    1998-01-01

    Since their emergence as a distinct fields of inquiry in the early post World War II period there has been an uneasy relationship between growth economics and development economics. The emergence of a richer new growth economics' has opened up the possibilities of a more fruitful dialogue between the two subdisciplines. In spite of recent advances, particularly with respect to the human capital, and understanding of differences in growth rates and income levels across countries remains elusiv...

  10. Attenuation of a drug-sensitive strain of a turkey protozoan parasite Eimeria meleagrimitis by selection for precocious development.

    Science.gov (United States)

    Rathinam, T; Gadde, U; Chapman, H D

    2016-01-30

    An attenuated line of Eimeria meleagrimitis was established by repeated propagation of the parasite in 9-day old turkey poults and subsequent selection for precocious development. Following 20 passages, the prepatent period decreased from 120 to 104h. A series of experiments were conducted to evaluate the pathogenicity, immunogenicity and fecundity of the newly selected line. Judged by body weight gain, feed consumption and feed efficiency following infection, the attenuated line had appreciably reduced pathogenicity. Immunogenicity of the attenuated line was examined by infecting poults successively with incremental doses of 10(2), 10(3) and 10(4) oocysts at 0, 7, and 14 days of age respectively. No oocysts were detected following challenge with 5×10(2) oocysts, indicating that the attenuated line had retained immunogenicity. Fecundity was assessed by infecting two-week old birds with 5×10(2) oocysts of either parent or attenuated line. Oocyst production from 96 to 240h post-infection showed that the patent period of the attenuated line commenced earlier and was of shorter duration than the parent line. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Development and reproductive potential of Tyrophagus putrescentiae (Acari: Acaridae) on plant-parasitic nematodes and artificial diets.

    Science.gov (United States)

    Abou El-Atta, Doaa Abd El-Maksoud; Osman, Mohamed Ali

    2016-04-01

    This study investigated development, reproduction and life table parameters of the astigmatid mold mite Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) feeding on egg-masses or adult females of the nematode Meloidogyne incognita, egg-masses of the nematode Rotylenchulus reniformis, ras cheese or yeast at 25 ± 1 °C, 70 ± 10 % RH in the dark. Immature developmental times were shorter when the mite was fed females of M. incognita followed by yeast. Different prey/diet types had no significant effect on longevity and lifespan of both males and females. Daily oviposition rate (eggs/female/day) was highest for mites fed yeast (20.8 ± 1.8 eggs) and lowest for mites fed females of M. incognita (6.6 ± 0.5). Intrinsic rate of natural increase (r m) was highest for mites fed yeast compared to other prey/diet; no significant differences in r m were observed among mites fed on non-yeast diets. This result may suggest a role of T. putrescentiae as biocontrol agent of plant-parasitic nematodes and the yeast may be used for mite mass-production purposes.

  12. Financial Development Following Economic Growth: The Chinese Case

    Directory of Open Access Journals (Sweden)

    Chan il Park

    2003-06-01

    Full Text Available The purpose of this paper is to investigate the relationship between financial development and economic growth based on Chinese experiences during the period of 1979~2000. This study places more emphasis on the causality running from economic growth to financThe purpose of this paper is to investigate the relationship between financial development and economic growth based on Chinese experiences during the period of 1979~2000. This study places more emphasis on the causality running from economic growth to financial development contrary to the mainstream view, which asserts that the well-functioning financial systems exert a large positive impact on economic growth via two channels- capital accumulation and technological innovations. The reverse causality is postulated by considering two factors in developments of the country's financial system. Firstly, this paper argues that the rapid accumulation of financial assets and the remarkable expansion of the financial system during the examined period are due primarily to income rises and changes in industrial structures rather than inefficient financial reforms. Secondly, it is recognized in this study that various financial reform measures undertaken by the state since 1994 are emerged endogenously in response to Chinese financial disorders and macroeconomic imbalances built up during the 1979~93 period. This line of thinking is not following the mainstream view in which financial reforms are regarded as policy variables (or exogenous variables in promoting economic growth. These two factors imply that the causality may run from economic growth to financial development at least in China.

  13. Financial Development and Inclusive Growth in Nigeria: A Threshold Analysis

    Directory of Open Access Journals (Sweden)

    Taofeek Olusola Ayinde

    2016-10-01

    Full Text Available This study investigates the relationship between financial development and inclusive growth in Nigeria for the period 1980 – 2013. The technique of analysis is the quantile regression; which is to obtain a threshold for which the former impacts on the latter. The result shows a threshold level of 90th percentile. Interestingly, the study also found that the impact of financial development on inclusive growth depends on the measure of the former up to the threshold level and not beyond. Through a granger causality test, the direction of causality is through the inclusive growth rather than through financial development; through the financial deepening measure. While the study found that either a low level or high level of openness on trade and capital investment are desirable for inclusive growth in Nigeria, the results also reveal that government involvement in the workings of the Nigeria economy and financial openness are sensitive to the pattern of financial development. With financial deepening, both are negatively related to inclusive growth but positively related to inclusive growth when financial widening is considered. This suggests that government intervention in the activities of the private sector is detrimental when the latter are to drive financial development process. However, the involvement of government in ensuring the appropriate level of financial widening, through the central bank operations, produces a positive impact on growth.

  14. Financial Development and Inclusive Growth in Nigeria: A Threshold Analysis

    Directory of Open Access Journals (Sweden)

    Taofeek Olusola Ayinde

    2016-08-01

    Full Text Available This study investigates the relationship between financial development and inclusive growth in Nigeria for the period 1980 – 2013. The technique of analysis is the quantile regression; which is to obtain a threshold for which the former impacts on the latter. The result shows a threshold level of 90th percentile. Interestingly, the study also found that the impact of financial development on inclusive growth depends on the measure of the former up to the threshold level and not beyond. Through a granger causality test, the direction of causality is through the inclusive growth rather than through financial development; through the financial deepening measure. While the study found that either a low level or high level of openness on trade and capital investment are desirable for inclusive growth in Nigeria, the results also reveal that government involvement in the workings of the Nigeria economy and financial openness are sensitive to the pattern of financial development. With financial deepening, both are negatively related to inclusive growth but positively related to inclusive growth when financial widening is considered. This suggests that government intervention in the activities of the private sector is detrimental when the latter are to drive financial development process. However, the involvement of government in ensuring the appropriate level of financial widening, through the central bank operations, produces a positive impact on growth.

  15. Foreign aid, governance quality, and economic growth in developing countries : foreign aid and growth

    OpenAIRE

    Biboh, Nkoumboh Henrietta

    2007-01-01

    Most poor developing countries, especially those with limited natural resources, low savings and investment levels, natural disaster stricken, need help from the affluent nations in order to meet some of their development objectives. Still, some that are rich in natural resources equally depend on some form of aid. Though most growth theories stress on investment as an important step to steady economic growth, they are mostly silent on the importance of aid as a component of in vestment and...

  16. Growth and Project Finance in the Least Developed Countries

    DEFF Research Database (Denmark)

    la Cour, Lisbeth F.; Müller, Jennifer

    2014-01-01

    for economic growth in LDCs. We find that a higher regulatory quality, lower government consumption and a higher level of education helps increase growth. The significance of these variables are, however, not as consistently robust as the results for project finance.......This article examines the effects of project finance on economic growth in the least developed countries (LDC). Inspired by the neoclassical growth model we set up an econometric model to estimate the effects of project finance for a sample consisting of 38 of the least developed countries using...... data from the period 1994-2007. The results of our study suggest, that project finance has a significant positive effect on economic growth and therefore constitute an important source of financing in the selected set of countries. Additionally, the project sheds light on other factors of importance...

  17. Framework for Creating a Smart Growth Economic Development Strategy

    Science.gov (United States)

    This step-by-step guide can help small and mid-sized cities, particularly those that have limited population growth, areas of disinvestment, and/or a struggling economy, build a place-based economic development strategy.

  18. Inclusive growth and development: An IDRC-World Economic Forum ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Advancing economic growth while achieving broad-based progress in living ... It will develop regional and global platforms whereby the private sector, local ... cooperation agreement to support joint research projects in December 2017.

  19. Postnatal growth, age estimation and development of foraging ...

    Indian Academy of Sciences (India)

    Unknown

    mothers. There was no significant difference in the growth pattern of the young maintained in captivity compared ..... interactions, and development of vocalizations in the vesper- ... Kunz T H and Hood W R 2000 Parental care and postnatal.

  20. How do mean division shares affect growth and development

    Directory of Open Access Journals (Sweden)

    Shao Liang Frank

    2017-01-01

    Full Text Available The Gini coefficient is widely used in academia to discuss how income inequality affects development and growth. However, different Lorenz curves may provide different development and growth outcomes while still leading to the same Gini coefficient. This paper studies the development effects of “mean division shares”, i.e., the share of income (mean income share held by people whose household disposable income per capita is below the mean income and the share of the population (mean population share with this income, using panel data. Our analysis explores how this income share and population share impact development and growth. It shows that the income and population shares affect growth in significantly different ways and that an analysis of these metrics provides substantial value compared to that of the Gini coefficient.

  1. The Effect of Temperature on Synchronization of Brood Development of the Bopyrid Isopod Parasite Probopyrus pandalicola with Molting of Its Host, the Daggerblade Grass Shrimp Palaemonetes pugio.

    Science.gov (United States)

    Brinton, Brigette A; Curran, Mary Carla

    2015-08-01

    The bopyrid isopod Probopyrus pandalicola is a hematophagous ectoparasite that sexually sterilizes some palaemonid shrimps, including female daggerblade grass shrimp Palaemonetes pugio. The reproduction of parasitic isopods is thought to occur synchronously with host molting because the brood would be unsuccessful if molting occurred before the larvae were free swimming. Temperature affects the length of the molting cycle of shrimp, and therefore may also affect the incubation time of isopod broods. The purpose of the present study was to determine the effect of temperature on brood development of the parasite and on the degree of synchronization with the molting of its host. Parasitized P. pugio were monitored daily at 2 experimental temperatures, 23 and 15 C, in temperature-controlled chambers for the duration of a full parasite reproductive cycle. Developmental stage was determined by the visible coloration of the brood through the exoskeleton of the host, and was designated as egg, embryo I, embryo II, or epicaridium larvae. Temperature significantly affected median brood incubation time, which was only 11 days at 23 C, as compared to 35 days at 15 C. The final developmental stage (epicaridium larvae) was 3 times shorter at 23 C (median 3 days; n = 45) than at 15 C (median 9 days; n = 15). Temperature significantly affected the intermolt period of parasitized shrimp, which was shorter at 23 C (median 12 days) than at 15 C (median 37 days). A smaller percentage of the intermolt period elapsed between larval release and shrimp molting at 23 C (0.0%) than at 15 C (3.1%), indicating closer synchronization between host molting and parasite reproduction at the warmer temperature. At 15 C, the isopods utilized a smaller proportion of the time that was available for brood incubation during the intermolt period of their host. Brood size ranged from 391 to 4,596 young and was positively correlated with parasite and host size. Because development progressed more rapidly

  2. Law, Economic Growth and Human Development: Evidence from Africa

    OpenAIRE

    Asongu Simplice

    2011-01-01

    This paper cuts adrift the mainstream approach to the legal-origins debate on the law-growth nexus by integrating both overall economic and human components in our understanding of how regulation quality and the rule of law lie at the heart of economic and inequality adjusted human developments. Findings summarily reveal that legal-origin does not explain economic growth and human development beyond the mechanisms of law. Our results support the current consensus that, English common-law coun...

  3. Financial development and economic growth in Ghana: Does the measure of financial development matter?

    Directory of Open Access Journals (Sweden)

    George Adu

    2013-07-01

    Full Text Available The aim of this paper is to investigate the long-run growth effects of financial development in Ghana. We find that the growth effect of financial development is sensitive to the choice of proxy. Both the credit to the private sector as ratios to GDP and total domestic credit are conducive for growth, while broad money stock to GDP ratio is not growth-inducing. The indexes created from principal component analysis confirmed the sensitivity of the effect to the choice of proxy. The findings here suggest that whether financial development is good or bad for growth depends on the indicator used to proxy for financial development.

  4. Financial Development and Economic Growth: Experiences of Selected Developing Economies

    OpenAIRE

    Ahmed, Syed; Horner, James; Rafiq, Rafiqul Bhuyan

    2008-01-01

    The last two decades of the twentieth century witnessed a series of financial reforms in emerging economics of Asia, Africa and Latin America. The seminal works of R.I. McKinnon and E.S. Shaw, which attribute the slow growth of these economies to financial repression, inspired many of these reforms. The McKinnon-Shaw thesis demonstrates how government regulations cause low savings and investment, and ultimately engender financial repression. Financial liberalization, in this view, creates mar...

  5. Nuclear energy consumption and economic growth in nine developed countries

    International Nuclear Information System (INIS)

    Wolde-Rufael, Yemane; Menyah, Kojo

    2010-01-01

    This article attempts to test the causal relationship between nuclear energy consumption and real GDP for nine developed countries for the period 1971-2005 by including capital and labour as additional variables. Using a modified version of the Granger causality test developed by Toda and Yamamoto (1995), we found a unidirectional causality running from nuclear energy consumption to economic growth in Japan, Netherlands and Switzerland; the opposite uni-directional causality running from economic growth to nuclear energy consumption in Canada and Sweden; and a bi-directional causality running between economic growth and nuclear energy consumption in France, Spain, the United Kingdom and the United States. In Spain, the United Kingdom and the USA, increases in nuclear energy consumption caused increases in economic growth implying that conservation measures taken that reduce nuclear energy consumption may negatively affect economic growth. In France, Japan, Netherlands and Switzerland increases in nuclear energy consumption caused decreases in economic growth, suggesting that energy conservation measure taken that reduce nuclear energy consumption may help to mitigate the adverse effects of nuclear energy consumption on economic growth. In Canada and Sweden energy conservation measures affecting nuclear energy consumption may not harm economic growth.

  6. Redefining Individual Growth and Development Indicators: Oral Language

    Science.gov (United States)

    Bradfield, Tracy A.; Besner, Amanda C.; Wackerle-Hollman, Alisha K.; Albano, Anthony D.; Rodriguez, Michael C.; McConnell, Scott R.

    2014-01-01

    Language skills developed during preschool contribute strongly to later reading and academic achievement. Effective preschool assessment and intervention should focus on core components of language development, specifically oral language skills. The Early Language and Literacy Individual Growth and Development Indicators (IGDIs) are a set of…

  7. Using GIS for Developing Sustainable Urban Growth Case Kyrenia Region

    Science.gov (United States)

    Kara, C.; Akçit, N.

    2018-03-01

    It is critical to develop urban layers for analysis sustainable urban development possibilities within planning process. Kyrenia Region has many physical, environmental or economic issues that may danger the growth possibilities in sustainable manner. From this point, this study uses different spatial layers such as slope, distance to roads, distance to central zone, vegetation, soil productivity, environmental protection zones, distance to open/green space, distance to education for supporting sustainable urban growth policies and define suitable areas for urban development within this perspective. The study tries to convert sustainable urban growth policies such as; compact growth, environmental protection, equal accessibility to basic services; into spatial layers and establish proper framework for multi criteria evaluation in Kyrenia Region within using geographical information systems. It shows suitability values for Kyrenia region and constraints zones at final section. It clearly presents the suitable areas for the sustainable urbanization and also unsuitable or risky areas for reducing the possible disasters and may happen in the future.

  8. A new system for sodium flux growth of bulk GaN. Part I: System development

    Science.gov (United States)

    Von Dollen, Paul; Pimputkar, Siddha; Alreesh, Mohammed Abo; Albrithen, Hamad; Suihkonen, Sami; Nakamura, Shuji; Speck, James S.

    2016-12-01

    Though several methods exist to produce bulk crystals of gallium nitride (GaN), none have been commercialized on a large scale. The sodium flux method, which involves precipitation of GaN from a sodium-gallium melt supersaturated with nitrogen, offers potentially lower cost production due to relatively mild process conditions while maintaining high crystal quality. We successfully developed a novel apparatus for conducting crystal growth of bulk GaN using the sodium flux method which has advantages with respect to prior reports. A key task was to prevent sodium loss or migration from the growth environment while permitting N2 to access the growing crystal. We accomplished this by implementing a reflux condensing stem along with a reusable capsule containing a hermetic seal. The reflux condensing stem also enabled direct monitoring of the melt temperature, which has not been previously reported for the sodium flux method. Furthermore, we identified and utilized molybdenum and the molybdenum alloy TZM as a material capable of directly containing the corrosive sodium-gallium melt. This allowed implementation of a crucible-free system, which may improve process control and potentially lower crystal impurity levels. Nucleation and growth of parasitic GaN ("PolyGaN") on non-seed surfaces occurred in early designs. However, the addition of carbon in later designs suppressed PolyGaN formation and allowed growth of single crystal GaN. Growth rates for the (0001) Ga face (+c-plane) were up to 14 μm/h while X-ray omega rocking (ω-XRC) curve full width half-max values were 731″ for crystals grown using a later system design. Oxygen levels were high, >1019 atoms/cm3, possibly due to reactor cleaning and handling procedures.

  9. Growth and development of children with congenital heart disease.

    Science.gov (United States)

    Chen, Chi-Wen; Li, Chung-Yi; Wang, Jou-Kou

    2004-08-01

    Children with congenital heart disease (CHD) commonly experience delayed growth. Because growth and development are closely related, both should be considered when a child's progress is examined. This paper reports a study to evaluate and compare the growth and development of preschool children with CHD to those of normal preschool children. The heights and weights of 42 preschool children with CHD and 116 normal preschool children were compared with standard growth curves. Differences in development of personal and social skills, fine motor skills and adaptability, language, and gross motor skills were evaluated. Developmental skills were assessed using the Denver Developmental Screening Test II. A significant difference was found in both body height (P motor sections (P development. Learning about the growth and developmental differences between children with CHD and normal children may help parents of the former to detect problems associated with delayed growth and development earlier. These children and their families should have the opportunity to participate in a long-term, follow-up programme that provides information and encourages developmental progress. The results could serve as a reference for those in both clinical and community workers who provide nursing care to children with CHD.

  10. Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure-Activity Relationship Study.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Masi, Marco; Maddau, Lucia; Cimmino, Alessio; Evidente, Marco; Rubiales, Diego; Evidente, Antonio

    2016-06-29

    Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by testing the haustorium-inducing activity of the natural cyclohexene oxides, seven already known and four new hemisynthetic derivatives, in O. cumana, O. crenata, and S. hermonthica, to find a molecular specificity model required for haustorium induction. The results suggested that the haustorium-inducing activity is due to the possibility to convert the natural sphaeropsidone and natural and hemisynthetic derivatives in the corresponding 3-methoxyquinone and that the stereochemistry at C-5 also seems to affect this activity.

  11. Parasitic diseases of lungs

    International Nuclear Information System (INIS)

    Rozenshtraukh, L.C.; Rybakova, N.I.; Vinner, M.G.

    1987-01-01

    Roentgenologic semiotics of the main parasitic diseases of lungs is described: echinococcosis, paragonimiasis, cysticercosis, toxoplasmosis, ascariasis, amebiosis and some rarely met parasitic diseases

  12. Life insurance, financial development and economic growth in South Africa

    Directory of Open Access Journals (Sweden)

    Athenia Bongani Sibindi

    2014-09-01

    Full Text Available The life insurance sector may contribute to economic growth by its very mechanism of savings mobilisation and thereby performing an intermediation role in the economy. This ensures that capital is provided to deficient units who are in need of capital to finance their working capital requirements and invest in technology thereby resulting in an increase in output. In this way, it could be argued that life insurance development spurs financial development. In this article we investigate the causal relationship between the life insurance sector, financial development and economic growth in South Africa for the period 1990 to 2012. We make use of life insurance density as the proxy for life insurance development, real per capita growth domestic product as the proxy for economic growth and real broad money per capita as the proxy for financial development. We test for cointegration amongst the variables by applying the Johansen procedure and then proceed to test for Granger causality based on the vector error correction model (VECM. Our results confirm the existence of at least one cointegrating relationship amongst the variables. The results indicate that the direction of causality runs from the economy to the life insurance sector which is consistent with the “demand-following” insurance-growth hypothesis. There is also evidence of causality running from the economy to financial development which is consistent with the “demand following” finance-growth hypothesis. The results also reveal that life insurance complements economic growth in bringing about financial development further lending credence to the “complementarity” hypothesis

  13. Altered T cell memory and effector cell development in chronic lymphatic filarial infection that is independent of persistent parasite antigen.

    Directory of Open Access Journals (Sweden)

    Cathy Steel

    2011-04-01

    Full Text Available Chronic lymphatic filarial (LF infection is associated with suppression of parasite-specific T cell responses that persist even following elimination of infection. While several mechanisms have been implicated in mediating this T cell specific downregulation, a role for alterations in the homeostasis of T effector and memory cell populations has not been explored. Using multiparameter flow cytometry, we investigated the role of persistent filarial infection on the maintenance of T cell memory in patients from the filarial-endemic Cook Islands. Compared to filarial-uninfected endemic normals (EN, microfilaria (mf positive infected patients (Inf had a reduced CD4 central memory (T(CM compartment. In addition, Inf patients tended to have more effector memory cells (T(EM and fewer effector cells (T(EFF than did ENs giving significantly smaller T(EFF:T(EM ratios. These contracted T(CM and T(EFF populations were still evident in patients previously mf+ who had cleared their infection (CLInf. Moreover, the density of IL-7Rα, necessary for T memory cell maintenance (but decreased in T effector cells, was significantly higher on memory cells of Inf and CLInf patients, although there was no evidence for decreased IL-7 or increased soluble IL7-Rα, both possible mechanisms for signaling defects in memory cells. However, effector cells that were present in Inf and CLInf patients had lower percentages of HLA-DR suggesting impaired function. These changes in T cell populations appear to reflect chronicity of infection, as filarial-infected children, despite the presence of active infection, did not show alterations in the frequencies of these T cell phenotypes. These data indicate that filarial-infected patients have contracted T(CM compartments and a defect in effector cell development, defects that persist even following clearance of infection. The fact that these global changes in memory and effector cell compartments do not yet occur in infected children

  14. Insulin-like growth factors in embryonic and fetal growth and skeletal development (Review).

    Science.gov (United States)

    Agrogiannis, Georgios D; Sifakis, Stavros; Patsouris, Efstratios S; Konstantinidou, Anastasia E

    2014-08-01

    The insulin-like growth factors (IGF)-I and -II have a predominant role in fetal growth and development. IGFs are involved in the proliferation, differentiation and apoptosis of fetal cells in vitro and the IGF serum concentration has been shown to be closely correlated with fetal growth and length. IGF transcripts and peptides have been detected in almost every fetal tissue from as early in development as pre‑implantation to the final maturation stage. Furthermore, IGFs have been demonstrated to be involved in limb morphogenesis. However, although ablation of Igf genes in mice resulted in growth retardation and delay in skeletal maturation, no impact on outgrowth and patterning of embryonic limbs was observed. Additionally, various molecular defects in the Igf1 and Igf1r genes in humans have been associated with severe intrauterine growth retardation and impaired skeletal maturation, but not with truncated limbs or severe skeletal dysplasia. The conflicting data between in vitro and in vivo observations with regard to bone morphogenesis suggests that IGFs may not be the sole trophic factors involved in fetal skeletal growth and that redundant mechanisms may exist in chondro- and osteogenesis. Further investigation is required in order to elucidate the functions of IGFs in skeletal development.

  15. Effect of young maternal age and skeletal growth on placental growth and development.

    Science.gov (United States)

    Hayward, C E; Greenwood, S L; Sibley, C P; Baker, P N; Jones, R L

    2011-12-01

    Teenagers are susceptible to delivering small-for-gestational-age infants. Previous studies implicate continued skeletal growth as a contributory factor, and impaired placental development was the primary cause of fetal growth restriction in growing adolescent sheep. The aims of this study were to examine the impact of young maternal age and growth on placental development. Placentas were collected from 31 teenagers, of which 12 were growing and 17 non-growing based on knee height measurements. An adult control group (n = 12) was included. Placental weight and morphometric measurements of villous, syncytiotrophoblast, fibrin and vessel areas, as well as indices of proliferation and apoptosis, were analysed in relation to maternal growth and age. Growing teenagers had a higher birthweight:placental weight ratio than non-growing teenagers (p adult and teenage pregnancies. Maternal smoking, a potential confounding factor, did not exert a major influence on the placental parameters examined, except for a stimulatory effect on placental proliferation (p development, and is consistent with our recent observations that maternal growth was not detrimental to fetal growth. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Capital Market Development: A Spur to Economic Growth in Nigeria

    Directory of Open Access Journals (Sweden)

    Ismail O. Fasanya

    2013-10-01

    Full Text Available This paper examines the relationship between capital market development and Nigeria’s economic growth using data covering the range of 1981 to 2010 using a Johansen Cointegration technique to test for long run relationship among the variables under study. The empirical findings from the research work suggest that the capital market is an essential catalyst for economic growth and is on the average and beneficial to the economy. However, the high costs of raising capital and structural imbalances in the market as well as inconsistent government policies may distorts the speedy growth of the market and thus, limit its positive impact on the economy.

  17. Parasitic infections of the external eye.

    Science.gov (United States)

    Pahuja, Shivani; Puranik, Charuta; Jelliti, Bechir; Khairallah, Moncef; Sangwan, Virender S

    2013-08-01

    To review the published literature on parasitic infections of external eye. Published articles and case reports on parasitic infections of external eye were reviewed and relevant information was collected. Parasitic infections of the eye are rare. However, being more commonly seen in developing nations, they require active measures for screening, diagnosis, and therapy. Parasites of importance causing external ocular disease are protozoan parasites, such as Leishmania; metazoans, such as nematodes (roundworms), cestodes (tapeworms), and trematodes (flatworms); or ectoparasites, such as Phthirus pubis and Demodex.

  18. Growth and development and their environmental and biological determinants.

    Science.gov (United States)

    da Rocha Neves, Kelly; de Souza Morais, Rosane Luzia; Teixeira, Romero Alves; Pinto, Priscilla Avelino Ferreira

    2016-01-01

    To investigate child growth, cognitive/language development, and their environmental and biological determinants. This was a cross-sectional, predictive correlation study with all 92 children aged 24-36 months who attended the municipal early childhood education network in a town in the Vale do Jequitinhonha region, in 2011. The socioeconomic profile was determined using the questionnaire of the Associação Brasileira de Empresas de Pesquisa. The socio-demographicand maternal and child health profiles were created through a self-prepared questionnaire. The height-for-age indicator was selected to represent growth. Cognitive/language development was assessed through the Bayley Scale of Infant and Toddler Development. The quality of educational environments was assessed by Infant/Toddler Environment Scale; the home environment was assessed by the Home Observation for Measurement of the Environment. The neighborhood quality was determined by a self-prepared questionnaire. A multivariate linear regression analysis was performed. Families were predominantly from socioeconomic class D, with low parental education. The prevalence of stunted growth was 14.1%; cognitive and language development were below average at 28.6% and 28.3%, respectively. Educational institutions were classified as inadequate, and 69.6% of homes were classified as presenting a risk for development. Factors such as access to parks and pharmacies and perceived security received the worst score regarding neighborhood environment. Biological variables showed a greater association with growth and environmental variables with development. The results showed a high prevalence of stunting and below-average results for cognitive/language development among the participating children. Both environmental and biological factors were related to growth and development. However, biological variables showed a greater association with growth, whereas environmental variables were associated with development

  19. Growth and development and their environmental and biological determinants

    Directory of Open Access Journals (Sweden)

    Kelly da Rocha Neves

    2016-06-01

    Full Text Available Abstract Objective To investigate child growth, cognitive/language development, and their environmental and biological determinants. Methods This was a cross-sectional, predictive correlation study with all 92 children aged 24-36 months who attended the municipal early childhood education network in a town in the Vale do Jequitinhonha region, in 2011. The socioeconomic profile was determined using the questionnaire of the Associação Brasileira de Empresas de Pesquisa. The socio-demographicand maternal and child health profiles were created through a self-prepared questionnaire. The height-for-age indicator was selected to represent growth. Cognitive/language development was assessed through the Bayley Scale of Infant and Toddler Development. The quality of educational environments was assessed by Infant/Toddler Environment Scale; the home environment was assessed by the Home Observation for Measurement of the Environment. The neighborhood quality was determined by a self-prepared questionnaire. A multivariate linear regression analysis was performed. Results Families were predominantly from socioeconomic class D, with low parental education. The prevalence of stunted growth was 14.1%; cognitive and language development were below average at 28.6% and 28.3%, respectively. Educational institutions were classified as inadequate, and 69.6% of homes were classified as presenting a risk for development. Factors such as access to parks and pharmacies and perceived security received the worst score regarding neighborhood environment. Biological variables showed a greater association with growth and environmental variables with development. Conclusion The results showed a high prevalence of stunting and below-average results for cognitive/language development among the participating children. Both environmental and biological factors were related to growth and development. However, biological variables showed a greater association with growth, whereas

  20. Developing a financial inclusion index and inclusive growth in India

    OpenAIRE

    Susanta Kumar SETHY

    2016-01-01

    Financial inclusion is one of the systems through which Inclusive Growth can be achieved in developing countries like India where large sections are unable or hopeless to contribute in the financial system. An inclusive financial system mobilizes more resources for productive purposes leading to higher economic growth, better opportunities and reduction of poverty. This study, proposed an Index of financial inclusion – a multidimensional measure. The Financial Inclusion Index c...

  1. Human Capital, Population Growth and Economic Development: Beyond Correlations

    OpenAIRE

    Rosenzweig, Mark R.

    1987-01-01

    Empirical evidence on three assertions commonly-made by population policy advocates about the relationships among population growth, human capital formation and economic development is discussed and evaluated in the light of economic-biological models of household behavior and of its relevance to population policy. The three assertions are that (a) population growth and human capital investments jointly reflect and respond to changes in the economic environment, (b) larger families directly i...

  2. Gender Inequality in Education: Impact on Income, Growth and Development

    OpenAIRE

    Moheyuddin, Ghulam

    2005-01-01

    This Paper explains the causes of the Gender Inequality of education and analyze how the gender inequality in education impacts the economic growth & development, investment and population growth etc. The paper finds that the gender inequality in education is as an endogenous variable and show that it can be explained to a considerable extent by religious preference, regional factors, and civil freedom. For some of these variables, the direction of the effect depends on the particular measure...

  3. Growth and development of the impala Aepyceros melampus

    Directory of Open Access Journals (Sweden)

    N. Fairall

    1976-08-01

    Full Text Available Growth and development of the prenatal impala has been described by Fairall (1969 and Roettcher, Hoffman and Kayanja (1970 while weights and measurements of the mature animal have been reported by Sachs (1967 and Talbot and McCulloch (1965. Child (1964 has investigated growth in this species. This paper serves as a baseline for comparison of future changes in morphology of the species, as the animals were all obtained at the beginning of the culling programme.

  4. Auxin-BR Interaction Regulates Plant Growth and Development

    Science.gov (United States)

    Tian, Huiyu; Lv, Bingsheng; Ding, Tingting; Bai, Mingyi; Ding, Zhaojun

    2018-01-01

    Plants develop a high flexibility to alter growth, development, and metabolism to adapt to the ever-changing environments. Multiple signaling pathways are involved in these processes and the molecular pathways to transduce various developmental signals are not linear but are interconnected by a complex network and even feedback mutually to achieve the final outcome. This review will focus on two important plant hormones, auxin and brassinosteroid (BR), based on the most recent progresses about these two hormone regulated plant growth and development in Arabidopsis, and highlight the cross-talks between these two phytohormones. PMID:29403511

  5. Development and Validation of a Biodynamic Model for Mechanistically Predicting Metal Accumulation in Fish-Parasite Systems.

    Directory of Open Access Journals (Sweden)

    T T Yen Le

    Full Text Available Because of different reported effects of parasitism on the accumulation of metals in fish, it is important to consider parasites while interpreting bioaccumulation data from biomonitoring programmes. Accordingly, the first step is to take parasitism into consideration when simulating metal bioaccumulation in the fish host under laboratory conditions. In the present study, the accumulation of metals in fish-parasite systems was simulated by a one-compartment toxicokinetic model and compared to uninfected conspecifics. As such, metal accumulation in fish was assumed to result from a balance of different uptake and loss processes depending on the infection status. The uptake by parasites was considered an efflux from the fish host, similar to elimination. Physiological rate constants for the uninfected fish were parameterised based on the covalent index and the species weight while the parameterisation for the infected fish was carried out based on the reported effects of parasites on the uptake kinetics of the fish host. The model was then validated for the system of the chub Squalius cephalus and the acanthocephalan Pomphorhynchus tereticollis following 36-day exposure to waterborne Pb. The dissolved concentration of Pb in the exposure tank water fluctuated during the exposure, ranging from 40 to 120 μg/L. Generally, the present study shows that the one-compartment model can be an effective method for simulating the accumulation of metals in fish, taking into account effects of parasitism. In particular, the predicted concentrations of Cu, Fe, Zn, and Pb in the uninfected chub as well as in the infected chub and the acanthocephalans were within one order of magnitude of the measurements. The variation in the absorption efficiency and the elimination rate constant of the uninfected chub resulted in variations of about one order of magnitude in the predicted concentrations of Pb. Inclusion of further assumptions for simulating metal accumulation

  6. Growth and development rates have different thermal responses.

    Science.gov (United States)

    Forster, Jack; Hirst, Andrew G; Woodward, Guy

    2011-11-01

    Growth and development rates are fundamental to all living organisms. In a warming world, it is important to determine how these rates will respond to increasing temperatures. It is often assumed that the thermal responses of physiological rates are coupled to metabolic rate and thus have the same temperature dependence. However, the existence of the temperature-size rule suggests that intraspecific growth and development are decoupled. Decoupling of these rates would have important consequences for individual species and ecosystems, yet this has not been tested systematically across a range of species. We conducted an analysis on growth and development rate data compiled from the literature for a well-studied group, marine pelagic copepods, and use an information-theoretic approach to test which equations best describe these rates. Growth and development rates were best characterized by models with significantly different parameters: development has stronger temperature dependence than does growth across all life stages. As such, it is incorrect to assume that these rates have the same temperature dependence. We used the best-fit models for these rates to predict changes in organism mass in response to temperature. These predictions follow a concave relationship, which complicates attempts to model the impacts of increasing global temperatures on species body size.

  7. The impact of globalization on the industrial growth of developing ...

    African Journals Online (AJOL)

    This paper is an attempt to investigate the impact of globalization on the industrial growth of developing economies with special reference to Nigeria. Globalization has facilitated the increased flow of ideas; people, goods and services across national frontiers. Some developing countries as a result of globalization have ...

  8. Foreign direct investment, financial development and economic growth

    NARCIS (Netherlands)

    Hermes, C.L.M.; Lensink, B.W.

    2003-01-01

    This article argues that the development of the financial system of the recipient country is an important precondition for FDI to have a positive impact on economic growth. A more developed financial system positively contributes to the process of technological diffusion associated with FDI. The

  9. Double impact: natural molluscicide for schistosomiasis vector control also impedes development of Schistosoma mansoni cercariae into adult parasites.

    Directory of Open Access Journals (Sweden)

    Ronaldo de Carvalho Augusto

    2017-07-01

    Full Text Available Schistosomiasis has been reported in 78 endemic countries and affects 240 million people worldwide. The digenetic parasite Schistosoma mansoni needs fresh water to compete its life cycle. There, it is susceptible to soluble compounds that can affect directly and/or indirectly the parasite's biology. The cercariae stage is one of the key points in which the parasite is vulnerable to different soluble compounds that can significantly alter the parasite's life cycle. Molluscicides are recommended by the World Health Organization for the control of schistosomiasis transmission and Euphorbia milii latex is effective against snails intermediate hosts.We used parasitological tools and electron microscopy to verify the effects of cercariae exposure to natural molluscicide (Euphorbia milii latex on morphology, physiology and fitness of adult parasite worms. In order to generate insights into key metabolic pathways that lead to the observed phenotypes we used comparative transcriptomics and proteomics.We describe here that the effect of latex on the adult is not due to direct toxicity but it triggers an early change in developmental trajectory and perturbs cell memory, mobility, energy metabolism and other key pathways. We conclude that latex has not only an effect on the vector but applies also long lasting schistosomastatic action. We believe that these results are of interest not only to parasitologists since it shows that natural compounds, presumably without side effects, can have an impact that occurred unexpectedly on developmental processes. Such collateral damage is in this case positive, since it impacts the true target of the treatment campaign. This type of treatment could also provide a rational for the control of other pests. Our results will contribute to enforce the use of E. milii latex in Brazil and other endemic countries as cheap alternative or complement to mass drug treatment with Praziquantel, the only available drug to cure the

  10. Population growth, human development, and deforestation in biodiversity hotspots.

    Science.gov (United States)

    Jha, S; Bawa, K S

    2006-06-01

    Human population and development activities affect the rate of deforestation in biodiversity hotspots. We quantified the effect of human population growth and development on rates of deforestation and analyzed the relationship between these causal factors in the 1980s and 1990s. We compared the averages of population growth, human development index (HDI, which measures income, health, and education), and deforestation rate and computed correlations among these variables for countries that contain biodiversity hotspots. When population growth was high and HDI was low there was a high rate of deforestation, but when HDI was high, rate of deforestation was low, despite high population growth. The correlation among variables was significant for the 1990s but not for the 1980s. The relationship between population growth and HDI had a regional pattern that reflected the historical process of development. Based on the changes in HDI and deforestation rate over time, we identified two drivers of deforestation: policy choice and human-development constraints. Policy choices that disregard conservation may cause the loss of forests even in countries that are relatively developed. Lack of development in other countries, on the other hand, may increase the pressure on forests to meet the basic needs of the human population. Deforestation resulting from policy choices may be easier to fix than deforestation arising from human development constraints. To prevent deforestation in the countries that have such constraints, transfer of material and intellectual resources from developed countries may be needed. Popular interest in sustainable development in developed countries can facilitate the transfer of these resources.

  11. Plant Growth Research for Food Production: Development and Testing of Expandable Tuber Growth Module

    Science.gov (United States)

    Cordova, Brennan A.

    2017-01-01

    Controlled and reliable growth of a variety of vegetable crops is an important capability for manned deep space exploration systems for providing nutritional supplementation and psychological benefits to crew members. Because current systems have been limited to leafy vegetables that require minimal root space, a major goal for these systems is to increase their ability to grow new types of crops, including tuber plants and root vegetables that require a large root space. An expandable root zone module and housing was developed to integrate this capability into the Veggie growth system. The expandable module uses a waterproof, gas-permeable bag with a structure that allows for root space to increase vertically throughout the growth cycle to accommodate for expanding tuber growth, while minimizing the required media mass. Daikon radishes were chosen as an ideal tuber crop for their subterraneous tuber size and rapid growth cycle, and investigations were done to study expanding superabsorbent hydrogels as a potential growth media. These studies showed improved water retention, but restricted oxygen availability to roots with pure gel media. It was determined that these hydrogels could be integrated in lower proportions into standard soil to achieve media expansion and water retention desired. Using the constructed module prototype and ideal gel and soil media mixture, Daikon radishes were grown in the system to test the capability and success of the system through a full growth cycle.

  12. Engineered nanomaterials for plant growth and development: A perspective analysis.

    Science.gov (United States)

    Verma, Sandeep Kumar; Das, Ashok Kumar; Patel, Manoj Kumar; Shah, Ashish; Kumar, Vinay; Gantait, Saikat

    2018-07-15

    With the overwhelmingly rapid advancement in the field of nanotechnology, the engineered nanomaterials (ENMs) have been extensively used in various areas of the plant system, including quality improvement, growth and nutritional value enhancement, gene preservation etc. There are several recent reports on the ENMs' influence on growth enhancements, growth inhibition as well as certain toxic impacts on plant. However, translocation, growth responses and stress modulation mechanisms of ENMs in the plant systems call for better and in-depth understanding. Herein, we are presenting a comprehensive and critical account of different types of ENMs, their applications and their positive, negative and null impacts on physiological and molecular aspects of plant growth, development and stress responses. Recent reports revealed mixed effects on plants, ranging from enhanced crop yield, epi/genetic alterations, and phytotoxicity, resulting from the ENMs' exposure. Creditable research in recent years has revealed that the effects of ENMs on plants are species specific and are variable among plant species. ENM exposures are reported to trigger free radical formation, responsive scavenging, and antioxidant armories in the exposed plants. The ENMs are also reported to induce aberrant expressions of microRNAs, the key post-transcriptional regulators of plant growth, development and stress-responses of plants. However, these modulations, if judiciously done, may lead to improved plant growth and yield. A better understanding of the interactions between ENMs and plant responses, including their uptake transport, internalization, and activity, could revolutionize crop production through increased disease resistance, nutrient utilization, and crop yield. Therefore, in this review, we are presenting a critical account of the different selected ENMs, their uptake by the plants, their positive/negative impacts on plant growth and development, along with the resultant ENM-responsive post

  13. Evidence on Economic Growth and Financial Development in Montenegro

    Directory of Open Access Journals (Sweden)

    Milena Lipovina-Bozovic

    2016-12-01

    Full Text Available Macroeconomic development must be supported by a stable and efficient financial system. There are many different measures of financial development that are suggested when the relationship between growth and financial system is analyzed. In this paper we will identify the most important indicators of the financial development in Montenegro. Due to the fact that in the last decade Montenegrin financial market has been developing, we want to see if that fact had an influence on the economic growth, as well as if there is significant positive relationship between the growth and financial development. The intention of this article is to use principal components in order to examine correlation among indicators and find means or main components. This technique has the advantage of giving more general measures of financial development rather than individual variables for bank or stock market development. It could be concluded that it is difficult to identify the specific components of the financial system most associated with the economic growth.

  14. Posterior cranial base natural growth and development: A systematic review.

    Science.gov (United States)

    Currie, Kris; Sawchuk, Dena; Saltaji, Humam; Oh, Heesoo; Flores-Mir, Carlos; Lagravere, Manuel

    2017-11-01

    To provide a synthesis of the published studies evaluating the natural growth and development of the human posterior cranial base (S-Ba). The search was performed on MEDLINE, Embase, PubMed, and all EBM Reviews electronic databases. In addition, reference lists of the included studies were hand-searched. Articles were included if they analyzed posterior cranial-base growth in humans specifically. Study selection, data extraction, and risk of bias assessment were completed in duplicate. A meta-analysis was not justified. Finally, 23 published studies were selected: 5 cross-sectional and 18 cohort studies. Articles were published between 1955 and 2015, and all were published in English. The sample sizes varied between 20 and 397 individuals and consisted of craniofacial measurements from either living or deceased human skulls. Validity of the measurements was not determined in any of the studies, while six papers reported some form of reliability assessment. All the articles included multiple time points within the same population or data from multiple age groups. Growth of S-Ba was generally agreed to be from spheno-occipital synchondrosis growth. Basion displaced downward and backward and sella turcica moved downward and backward during craniofacial growth. Timing of cessation of S-Ba growth was not conclusive due to limited identified evidence. Current evidence suggests that S-Ba is not totally stable, as its dimensions change throughout craniofacial growth and a minor dimensional change is observed even in late adulthood.

  15. Ketoconazole inhibits the growth and development of Ichthyophonus sp. (Mesomycetozoa) in vitro.

    Science.gov (United States)

    Hontoria, Francisco; González, M Angeles; Sitjà-Bobadilla, Ariadna; Palenzuela, Oswaldo; Alvarez-Pellitero, Pilar

    2009-01-01

    We determined the in vitro effect of the azol-derivative antifungal ketoconazole (KZ) on the morphology, growth, and development of teleost fish parasite Ichthyophonus sp. The KZ was delivered to culture medium using liposomes (L) or a lipid emulsion (E) at five different doses (i.e. 5, 50, 100, 200, and 400 microg/ml) for both L and E formulations. Controls consisted of Eagle's minimum essential medium (MEM) supplemented with 10% foetal bovine serum (MEM-10) alone (C-MEM) or containing amounts of L or E equivalent to those used in the KZ100 and KZ400 treatments (i.e. 100L, 400L, 100E, and 400E, respectively). Morphological alterations, such as a decrease in the number of dividing spores and nuclei, and condensation or even destruction of the cytoplasm, were observed using light and electron microscopy in the MEM-cultured organisms receiving KZ formulations, especially with KZ400L preparations, at both 7- and 14-d postinoculation. The KZ treatments also demonstrated a statistically significant inhibition of Ichthyophonus growth in MEM. These treatments also had an inhibitory effect on subsequent Ichthyophonus germination in Earle's fish saline agar (EFSA) medium, which was more evident for L formulations when the organism was treated for 7 d and for E formulations at 14 d. Our results endorse the potential use of KZ for the treatment for ichthyophonosis and provide support to proceed to in vivo assays.

  16. Metropolitan migration and population growth in selected developing countries.

    Science.gov (United States)

    1983-01-01

    The purpose of this article is to estimate the components of metropolitan population growth in selected developing countries during 1960-1970 period. The study examines population growth in 26 cities: 5 are in Africa, 8 in Asia, and 13 in Latin America, using data from national census publications. These cities in general are the political capitals of their countries, but some additional large cities were selected in Brazil, Mexico, and South Africa. All cities, at the beginning of the 1960-1970 decade had over 500,000 population; Accra, the only exception, reached this population level during the 1960s. Some cities had over 4 million residents in 1970. Net migration contributed about 37% to total metropolitan population growth; the remainder of the growth is attributable to natural increase. Migration has a much stronger impact on metropolitan growth than suggested by the above figure: 1) Several metropolitan areas, for various reasons, are unlikely to receive many migrants; without those cities, the share of metropolitan growth from net migration is 44%. 2) Estimates of the natural increase of migrants after their arrival in the metropolitan areas, when added to migration itself, changes the total contribution of migration to 49% in some metropolitan areas. 3) Even where net migration contributes a smaller proportion to metropolitan growth than natural increase, the rates of net migration are generally high and should be viewed in the context of rapid metropolitan population growth from natural increase alone. Finally, the paper also compares the components of metropolitan growth with the components of growth in the remaining urban areas. The results show that the metropolitan areas, in general, grow faster than the remaining urban areas, and that this more rapid growth is mostly due to a higher rate of net migration. Given the significance of migration for metropolitan growth, further investigations of the effects of these migration streams, particularly with

  17. Dectin-1 Positive Dendritic Cells Expand after Infection with Leishmania major Parasites and Represent Promising Targets for Vaccine Development

    Science.gov (United States)

    Zimara, Nicole; Chanyalew, Menberework; Aseffa, Abraham; van Zandbergen, Ger; Lepenies, Bernd; Schmid, Maximilian; Weiss, Richard; Rascle, Anne; Wege, Anja Kathrin; Jantsch, Jonathan; Schatz, Valentin; Brown, Gordon D.; Ritter, Uwe

    2018-01-01

    Resistant mouse strains mount a protective T cell-mediated immune response upon infection with Leishmania (L.) parasites. Healing correlates with a T helper (Th) cell-type 1 response characterized by a pronounced IFN-γ production, while susceptibility is associated with an IL-4-dependent Th2-type response. It has been shown that dermal dendritic cells are crucial for inducing protective Th1-mediated immunity. Additionally, there is growing evidence that C-type lectin receptor (CLR)-mediated signaling is involved in directing adaptive immunity against pathogens. However, little is known about the function of the CLR Dectin-1 in modulating Th1- or Th2-type immune responses by DC subsets in leishmaniasis. We characterized the expression of Dectin-1 on CD11c+ DCs in peripheral blood, at the site of infection, and skin-draining lymph nodes of L. major-infected C57BL/6 and BALB/c mice and in peripheral blood of patients suffering from cutaneous leishmaniasis (CL). Both mouse strains responded with an expansion of Dectin-1+ DCs within the analyzed tissues. In accordance with the experimental model, Dectin-1+ DCs expanded as well in the peripheral blood of CL patients. To study the role of Dectin-1+ DCs in adaptive immunity against L. major, we analyzed the T cell stimulating potential of bone marrow-derived dendritic cells (BMDCs) in the presence of the Dectin-1 agonist Curdlan. These experiments revealed that Curdlan induces the maturation of BMDCs and the expansion of Leishmania-specific CD4+ T cells. Based on these findings, we evaluated the impact of Curdlan/Dectin-1 interactions in experimental leishmaniasis and were able to demonstrate that the presence of Curdlan at the site of infection modulates the course of disease in BALB/c mice: wild-type BALB/c mice treated intradermally with Curdlan developed a protective immune response against L. major whereas Dectin-1−/− BALB/c mice still developed the fatal course of disease after Curdlan treatment. Furthermore

  18. Large-area sheet task advanced dendritic web growth development

    Science.gov (United States)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.

    1984-01-01

    The thermal models used for analyzing dendritic web growth and calculating the thermal stress were reexamined to establish the validity limits imposed by the assumptions of the models. Also, the effects of thermal conduction through the gas phase were evaluated and found to be small. New growth designs, both static and dynamic, were generated using the modeling results. Residual stress effects in dendritic web were examined. In the laboratory, new techniques for the control of temperature distributions in three dimensions were developed. A new maximum undeformed web width of 5.8 cm was achieved. A 58% increase in growth velocity of 150 micrometers thickness was achieved with dynamic hardware. The area throughput goals for transient growth of 30 and 35 sq cm/min were exceeded.

  19. Influence of Schistosoma japonicum programmed cell death protein 10 on the growth and development of schistosomula.

    Science.gov (United States)

    Gao, Yan Ru; Huang, Wen Ling; Tang, Chun Lian; Liu, Rong; Zhao, Qin Ping; Ming, Zhen Ping; Dong, Hui Fen

    2018-01-18

    Schistosomiasis caused by Schistosoma japonicum is among the most serious endemic zoonoses in China. To study interactions between schistosomula, the pre-adult juvenile stage, and hosts, it is important to study the functions of key genes involved in schistosomula growth and development. Programmed cell death protein 10 (pcdp10) is an important apoptosis-related gene with various biological functions. This study described the molecular characterization of S. japonicum PCDP10 (SjPCDP10) and evaluated its functions in schistosomula. Real-time quantitative polymerase chain reaction (qPCR) and western blot were used to detect Sjpcdp10 mRNA and protein levels, respectively, at different developmental stages. Immunolocalization was performed to determine SjPCDP10 expression in the parasite. RNA interference (RNAi) experiments were used to assess gene functions associated with SjPCDP10 in schistosomula growth and development. Real-time qPCR revealed that Sjpcdp10 was expressed during all investigated developmental stages and upregulated during schistosomula growth and development. Histochemical localization showed that SjPCDP10 was mainly distributed in the teguments of schistosomula in all investigated stages and part of the parenchymal area of 14-, 18-, and 21-day-old schistosomula. Following Sjpcdp10 knockdown by RNAi, the lengths, widths, areas, and volumes of schistosomula were significantly lower than those in the control group. Scanning electron microscopy showed that the body surfaces of schistosomula subjected to RNAi were seriously damaged, with few tegumental spines and sensory papillae. Transmission electron microscopy indicated that the teguments of Sjpcdp10-knockdown schistosomula were incomplete, the number of layers was reduced, and the thickness decreased significantly as compared with those in the control group. Furthermore, terminal deoxynucleotidyl transferase dUTP nick-end labelling results showed that the rate of apoptosis in Sjpcdp10-knockdown

  20. Eye growth and myopia development: Unifying theory and Matlab model.

    Science.gov (United States)

    Hung, George K; Mahadas, Kausalendra; Mohammad, Faisal

    2016-03-01

    The aim of this article is to present an updated unifying theory of the mechanisms underlying eye growth and myopia development. A series of model simulation programs were developed to illustrate the mechanism of eye growth regulation and myopia development. Two fundamental processes are presumed to govern the relationship between physiological optics and eye growth: genetically pre-programmed signaling and blur feedback. Cornea/lens is considered to have only a genetically pre-programmed component, whereas eye growth is considered to have both a genetically pre-programmed and a blur feedback component. Moreover, based on the Incremental Retinal-Defocus Theory (IRDT), the rate of change of blur size provides the direction for blur-driven regulation. The various factors affecting eye growth are shown in 5 simulations: (1 - unregulated eye growth): blur feedback is rendered ineffective, as in the case of form deprivation, so there is only genetically pre-programmed eye growth, generally resulting in myopia; (2 - regulated eye growth): blur feedback regulation demonstrates the emmetropization process, with abnormally excessive or reduced eye growth leading to myopia and hyperopia, respectively; (3 - repeated near-far viewing): simulation of large-to-small change in blur size as seen in the accommodative stimulus/response function, and via IRDT as well as nearwork-induced transient myopia (NITM), leading to the development of myopia; (4 - neurochemical bulk flow and diffusion): release of dopamine from the inner plexiform layer of the retina, and the subsequent diffusion and relay of neurochemical cascade show that a decrease in dopamine results in a reduction of proteoglycan synthesis rate, which leads to myopia; (5 - Simulink model): model of genetically pre-programmed signaling and blur feedback components that allows for different input functions to simulate experimental manipulations that result in hyperopia, emmetropia, and myopia. These model simulation programs

  1. Ethylene production throughout growth and development of plants

    Science.gov (United States)

    Wheeler, Raymond M.; Peterson, Barbara V.; Stutte, Gary W.

    2004-01-01

    Ethylene production by 10 or 20 m2 stands of wheat, soybean, lettuce, potato, and tomato was monitored throughout growth and development in an atmospherically closed plant chamber. Chamber ethylene levels varied among species and rose during periods of canopy expansion and rapid growth for all species. Following this, ethylene levels either declined during seed fill and maturation for wheat and soybean, or remained relatively constant for potato and tomato (during flowering and early fruit development). Lettuce plants were harvested during rapid growth and peak ethylene production. Chamber ethylene levels increased rapidly during tomato ripening, reaching concentrations about 10 times that measured during vegetative growth. The highest ethylene production rates during vegetative growth ranged from 1.6 to 2.5 nmol m-2 d-1 during rapid growth of lettuce and wheat stands, or about 0.3 to 0.5 nmol g-1 fresh weight per hour. Estimates of stand ethylene production during tomato ripening showed that rates reached 43 nmol m-2 d-1 in one study and 93 nmol m-2 d-1 in a second study with higher lighting, or about 50x that of the rate during vegetative growth of tomato. In a related test with potato, the photoperiod was extended from 12 to 24 hours (continuous light) at 58 days after planting (to increase tuber yield), but this change in the environment caused a sharp increase in ethylene production from the basal rate of 0.4 to 6.2 nmol m-2 d-1. Following this, the photoperiod was changed back to 12 h at 61 days and ethylene levels decreased. The results suggest three separate categories of ethylene production were observed with whole stands of plants: 1) production during rapid vegetative growth, 2) production during climacteric fruit ripening, and 3) production from environmental stress.

  2. Research & development and growth: A Bayesian model averaging analysis

    Czech Academy of Sciences Publication Activity Database

    Horváth, Roman

    2011-01-01

    Roč. 28, č. 6 (2011), s. 2669-2673 ISSN 0264-9993. [Society for Non-linear Dynamics and Econometrics Annual Conferencen. Washington DC, 16.03.2011-18.03.2011] R&D Projects: GA ČR GA402/09/0965 Institutional research plan: CEZ:AV0Z10750506 Keywords : Research and development * Growth * Bayesian model averaging Subject RIV: AH - Economic s Impact factor: 0.701, year: 2011 http://library.utia.cas.cz/separaty/2011/E/horvath-research & development and growth a bayesian model averaging analysis.pdf

  3. Teaching child growth and development: the Christmas shoebox.

    Science.gov (United States)

    Epp, Sheila M; McAulay, Judy E

    2008-01-01

    Teaching growth and development to nursing students can be dry, uninteresting, and labor-intensive. Engaging students in learning this material was the challenge of a short, 4-week pediatric experience. Students use growth and development knowledge to select toys and activities that fit in a shoebox and explain to their classmates the rationale for their selection. The Christmas shoebox activity increases their ability to transfer knowledge to both the examination questions and the clinical setting and provides a charitable service to the community.

  4. Lazy males and hardworking females? Sexual conflict over parental care in a brood parasite host and its consequences for chick growth

    Czech Academy of Sciences Publication Activity Database

    Požgayová, Milica; Beňo, Radovan; Procházka, Petr; Jelínek, Václav; Abraham, Marek Mihai; Honza, Marcel

    2015-01-01

    Roč. 69, č. 6 (2015), s. 1053-1061 ISSN 0340-5443 R&D Projects: GA ČR(CZ) GAP506/12/2404 Institutional support: RVO:68081766 Keywords : Acrocephalus arundinaceus * Brood parasitism * Cuculus canorus * Feeding * Parental investment * Social polygyny Subject RIV: EG - Zoology Impact factor: 2.382, year: 2015

  5. BUILDING NEW BUSINESS MODELS FOR SUSTAINABLE GROWTH AND DEVELOPMENT

    OpenAIRE

    Taco C. R. van Someren; Shuhua van Someren-Wang

    2011-01-01

    Considered are issues of methodology and methods, as well as ideology of strategic innovation. Using the tools of this approach is offered as mechanisms to develop and build business models for sustainable socio-economic economic growth and development of different regions. The connection between key problems of sustainable development and management policy of different economic entities is studied. The consultancy company Ynnovate’s experience in addressing these issues in the EU and China i...

  6. Ihh signaling regulates mandibular symphysis development and growth.

    Science.gov (United States)

    Sugito, H; Shibukawa, Y; Kinumatsu, T; Yasuda, T; Nagayama, M; Yamada, S; Minugh-Purvis, N; Pacifici, M; Koyama, E

    2011-05-01

    Symphyseal secondary cartilage is important for mandibular development, but the molecular mechanisms underlying its formation remain largely unknown. Here we asked whether Indian hedgehog (Ihh) regulates symphyseal cartilage development and growth. By embryonic days 16.5 to 18.5, Sox9-expressing chondrocytes formed within condensed Tgfβ-1/Runx2-expressing mesenchymal cells at the prospective symphyseal joint site, and established a growth-plate-like structure with distinct Ihh, collagen X, and osteopontin expression patterns. In post-natal life, mesenchymal cells expressing the Ihh receptor Patched1 were present anterior to the Ihh-expressing secondary cartilage, proliferated, differentiated into chondrocytes, and contributed to anterior growth of alveolar bone. In Ihh-null mice, however, symphyseal development was defective, mainly because of enhanced chondrocyte maturation and reduced proliferation of chondroprogenitor cells. Proliferation was partially restored in dual Ihh;Gli3 mutants, suggesting that Gli3 is normally a negative regulator of symphyseal development. Thus, Ihh signaling is essential for symphyseal cartilage development and anterior mandibular growth.

  7. The role of population on economic growth and development: evidence from developing countries

    OpenAIRE

    Atanda, Akinwande A.; Aminu, Salaudeen B.; Alimi, Olorunfemi Y.

    2012-01-01

    The precise relationship between population growth and per capita income has been inconclusive in the literature and the nexus has been found not clearly explain the determinants of rapid population growth in developing countries that lacks fertility control and management framework. This forms the rationale for this study to access the trend of factors that influence rapid population growth in developing countries between 1980 and 2010. This paper examined the comparative trend review of pop...

  8. Economic Growth of a Rapidly Developing Economy: Theoretical Formulation

    Directory of Open Access Journals (Sweden)

    Oleg Sergeyevich Sukharev

    2016-06-01

    Full Text Available The subject matter of the article is the description of economic growth. Modern economy is characterized by a high rate of changes. These changes are the limiting parameters of modern development, which requires a modification of the basic models of growth, the substantiation of the expediency and necessity of a rapid development strategy. In a simple mathematical form, the statement of the problem of economic growth in the “green economy” is examined, in which the costs of environmental measures are not considered a priori as hampering economic development (as it is common for a number of modern neoclassical and neo-Keynesian growth models. The methodological basis of the article are the econometric approach and modelling method. The article has a theoretical character. The main hypothesis supposes that the rapid development strategy cannot make an adequate development strategy under certain conditions, but may be acceptable in other its specific conditions. In this sense, the important growth conditions are the availability of resources, the effectiveness of institutions and the current economic structure, the technological effectiveness of economy, as well as the conditions of technological development (“green economy” and the path of such development. In the article, on the theoretical level of analysis, the substantiation of the adequacy of the rapid development strategy for an economic system is given, whose goal is to achieve the standard of living of the countryleader. Based on the assumptions introduced, the period for which the rapid development strategy might be implemented and the economic lag of the country might be reduced from the country-leader is determined. The conditions that ensure the impact of innovations on the rate of economic development are summarized. The introduced range of dependencies and relations can be useful for the elaboration of the theory of innovation development and for the formation of a new

  9. Life Insurance Contribution, Insurance Development and Economic Growth in China

    Directory of Open Access Journals (Sweden)

    Wang Ying

    2017-07-01

    Full Text Available Under L-type economy, remodelling the growth power in the medium and long term is essential. The insurance industry during the 13th Five-year Plan period has been given a heavy expectation on promoting economic quality and upgrading economic efficiency, so it will try to accelerate its innovation and development process which serves national needs, market demand and people's requirements. Referring to the previous researches of Solow and Zhang and measuring Capital Stock and Total Factor Productivity independently, the paper analyses the inherent correlation between insurance (including life insurance and non-life insurance and economic growth, reveals the contribution law of the insurance development in economic growth in the short and long term from both economic scale and quality respectively. It also shows enlightenments on policy decision for insurance industry, thus helps economic stability under the downturn periods.

  10. Large area sheet task: Advanced dendritic web growth development

    Science.gov (United States)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D.; Schruben, J.

    1981-01-01

    The growth of silicon dendritic web for photovoltaic applications was investigated. The application of a thermal model for calculating buckling stresses as a function of temperature profile in the web is discussed. Lid and shield concepts were evaluated to provide the data base for enhancing growth velocity. An experimental web growth machine which embodies in one unit the mechanical and electronic features developed in previous work was developed. In addition, evaluation of a melt level control system was begun, along with preliminary tests of an elongated crucible design. The economic analysis was also updated to incorporate some minor cost changes. The initial applications of the thermal model to a specific configuration gave results consistent with experimental observation in terms of the initiation of buckling vs. width for a given crystal thickness.

  11. Growth of a species, an association, a science: 80 years of growth and development research.

    Science.gov (United States)

    Sherwood, Richard J; Duren, Dana L

    2013-01-01

    Physical anthropological research was codified in the United States with the creation of the American Association of Physical Anthropology (AAPA) in 1929. That same year, a study began in yellow springs, Ohio, with a goal of identifying "what makes people different." The approach used to answer that question was to study the growth and development of Homo sapiens. The resulting study, the Fels Longitudinal Study, is currently the longest continuous study of human growth and development in the world. Although the AAPA and the Fels Longitudinal Study have existed as separate entities for more than 80 years now, it is not surprising, given the relationship between anatomical and developmental research, there has been considerable overlap between the two. As the field of physical anthropology has blossomed to include subdisciplines such as forensics, genetics, primatology, as well as sophisticated statistical methodologies, the importance of growth and development research has escalated. Although current Fels Longitudinal Study research is largely directed at biomedical questions, virtually all findings are relevant to physical anthropology, providing insights into basic biological processes and life history parameters. Some key milestones from the early years of the AAPA and the Fels Longitudinal Study are highlighted here that address growth and development research in physical anthropology. These are still held as fundamental concepts that underscore the importance of this line of inquiry, not only across the subdisciplines of physical anthropology, but also among anthropological, biological, and biomedical inquiries. Copyright © 2012 Wiley Periodicals, Inc.

  12. Alteration of rice growth and development via antisense expression ...

    African Journals Online (AJOL)

    user

    OsGA20ox2 in regulating plant growth and development, we used reverse genomic approach to ... pathways. Similarly, Carmen et al. (2007) suggested that. Carrizo citrange plants have produced antisense ... universal SP6 and T7 primers to conform their reality (Sangon, ..... Optimising the tissue culture conditions for.

  13. Economic Growth and Development in the Undergraduate Curriculum

    Science.gov (United States)

    Acemoglu, Daron

    2013-01-01

    A central theme of this article is that economics instructors should spend more time teaching about economic growth and development at the undergraduate level because the topic is of interest to students, is less abstract than other macroeconomic topics, and is the focus of exciting research in economics. Facts and data can be presented to…

  14. Development of a minimal growth medium for Lactobacillus plantarum

    NARCIS (Netherlands)

    Wegkamp, H.B.A.; Teusink, B.; Vos, de W.M.; Smid, E.J.

    2010-01-01

    Aim: A medium with minimal requirements for the growth of Lactobacillus plantarum WCFS was developed. The composition of the minimal medium was compared to a genome-scale metabolic model of L. plantarum. Methods and Results: By repetitive single omission experiments, two minimal media were

  15. Foreign direct investment, financial development and economic growth

    NARCIS (Netherlands)

    Hermes, Niels; Lensink, Robert

    2000-01-01

    FDI may help to raise economic growth in recipient countries. Yet, the contribution FDI can make may strongly depend on the circumstances in the recipient countries. This paper argues that the development of the financial system of the recipient country is an important precondition for FDI to have a

  16. The Contribution of food plants to the growth, development and ...

    African Journals Online (AJOL)

    The Contribution of food plants to the growth, development and fecundity of Zonocerus variegatus (L) ... African Journal of Biotechnology ... The performance of the variegated grasshopper, Zonocerus variegatus (L) fed on different food plants namely cassava (Manihot esculenta), pawpaw (Carica papaya) and acalypha ...

  17. Impact of Personal Growth Projects on Leadership Identity Development

    Science.gov (United States)

    Odom, Summer F.; Boyd, Barry L.; Williams, Jennifer

    2012-01-01

    Within personal leadership education courses, leadership educators should include experiences which help students develop themselves as leaders. In this article, the authors discuss results from a qualitative research study involving the analysis of Personal Growth Project (PGP) assignments in a personal leadership education collegiate course. The…

  18. The Role of Stock Market Development on Economic Growth in ...

    African Journals Online (AJOL)

    The method of analysis used is Ordinary Least Square (OLS) techniques. The study measures the relationship between stock market development indices and economic growth. The stock market capitalization ratio was used as a proxy for market size while value traded ratio and turnover ratio were used as proxy for market ...

  19. Foreign direct investment and economic growth in developing ...

    African Journals Online (AJOL)

    It has been widely claimed that foreign direct investment (FDI) stimulates economic growth. In this study, an attempt is made to verify this for ten selected Sub-Saharan African (SSA) countries using data spanning from 2008 to 2013 obtained from world development indicators. Preliminary analysis conducted indicates that ...

  20. Financial development and corporate growth in the EU single market

    Czech Academy of Sciences Publication Activity Database

    Bena, J.; Jurajda, Štěpán

    2011-01-01

    Roč. 78, č. 311 (2011), s. 401-428 ISSN 0013-0427 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : financial development * corporate growth * access to financial markets Subject RIV: AH - Economics Impact factor: 1.152, year: 2011

  1. Financial development and growth in direct firm-level comparisons

    Czech Academy of Sciences Publication Activity Database

    Bena, Jan; Jurajda, Š.

    -, č. 6395 (2007), s. 1-26 ISSN 0265-8003 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : access to financial markets * corporate growth * financial development Subject RIV: AH - Economics http://www.cepr.org/pubs/new-dps/dplist.asp?dpno=6395

  2. Financial development and growth in direct firm-level comparisons

    Czech Academy of Sciences Publication Activity Database

    Bena, Jan; Jurajda, Š.

    -, č. 317 (2007), s. 1-40 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : financial development * corporate growth * access to financial markets Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp317.pdf

  3. Financial development and growth in direct firm-level comparisons

    Czech Academy of Sciences Publication Activity Database

    Bena, J.; Jurajda, Štěpán

    -, č. 6395 (2007), s. 1-26 ISSN 0265-8003 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:MSM0021620846 Keywords : access to financial markets * corporate growth * financial development Subject RIV: AH - Economics http://www.cepr.org/pubs/new-dps/dplist.asp?dpno=6395

  4. Financial development and growth in direct firm-level comparisons

    Czech Academy of Sciences Publication Activity Database

    Bena, J.; Jurajda, Štěpán

    -, Č. 317 (2007), s. 1-40 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:MSM0021620846 Keywords : financial development * corporate growth * access to financial markets Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp317.pdf

  5. Effects of polymeric carbohydrates on growth and development in pigs

    DEFF Research Database (Denmark)

    Knudsen, Knud Erik Bach

    2011-01-01

    carbohydrates influence growth and development through different mechanisms. First, the proportion of starch to NSP plays an important role for the content of available energy (i.e., DE, ME, and NE); available energy relative to protein is crucial for performance and carcass quality. Second, the proportion...

  6. Models of economic growth and development in the context of ...

    African Journals Online (AJOL)

    It is argued that a very necessary condition for growth and transformational development in Africa is heavy investment in human capital. It is pointed out that countries that invest much human capital to produce highly educated populaces usually reap the benefits of such in terms of high per capita GDPs, regardless of the ...

  7. Soil science, population growth and food production: some historical developments

    NARCIS (Netherlands)

    Hartemink, A.E.

    2007-01-01

    The world¿s population has doubled since 1960. Currently, the developing world accounts for about 95% of the population growth with Africa as the world¿s fastest growing continent. The growing population has many implications but most of all it requires an increase in agricultural production to meet

  8. [Evaluation of growth and development of institutionalized children].

    Science.gov (United States)

    Chaves, Caroline Magna Pessoa; Lima, Francisca Elisângela Teixeira; Mendonça, Larissa Bento de Araújo; Custódio, Ires Lopes; Matias, Erica Oliveira

    2013-01-01

    The study aimed to evaluate the growth and development of institutionalized children from 0-6 years old. It had a descriptive, transversal and quantitative approach, and was held in a shelter from the Bureau of Labor and Social Development of the Government of the State of Ceará, in the months of March and April 2011. The sample comprised 44 children. It the sample prevailed male children (59.1%), aged 24 to 72 months (56.8%) and with time of sheltering more than one year (72.7%). It was found that the children were in the normal range of nutrition; however, 65.9% of children did not achieve at least one of the development milestones proposed by the Ministry of Health. The study suggests a reflection on how children living in shelters are being assisted by the health team, making it necessary follow up their growth and development, in order to intervene on the alterations.

  9. Explaining development aid allocation by growth: A meta study

    DEFF Research Database (Denmark)

    Doucouliagos, Hristos; Paldam, Martin

      an interesting factor for two reasons: (1) It is relatively easy to interpret the results, and (2) it  is an important piece in the picture which suggests aid ineffectiveness. The paper is a meta-analysis of the 211 growth-aid estimates found in the 30 empirical studies. Additionally, we present new evidence...... using a panel data for 147 countries for the period 1967-2004. The result from both the meta-analysis and the primary data analysis is that growth does generate aid, so the dominating sign is positive. This result is driven partly by the large development banks....

  10. Scaling of fecundity, growth and development in marine planktonic copepods

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Sabatini, M.

    1995-01-01

    We compiled information from the literature on female and egg sizes and maximum egg production, growth and developmental rates in marine planktonic copepods. While specific growth and developmental rates are invariant with body mass, weight- specific fecundity scales with female body mass(-0...... to 50% and have weight-specific fecundities that are 2.5 times and egg production rates that are 7.5 times those of the former, Nauplii develop faster (by a factor of 2) but grow slower (by 20 to 40%) than copepodites in both spawning types. The main demographic implications of these findings are (1...

  11. High power blue LED development using different growth modes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong S.; Florescu, Doru I.; Ramer, Jeff C.; Merai, Vinod; Parekh, Aniruddh; Begarney, Michael J.; Armour, Eric A. [Veeco TurboDisc Operations, 394 Elizabeth Avenue, Somerset, NJ 08873 (United States); Lu Dong [Veeco TurboDisc Operations, 394 Elizabeth Avenue, Somerset, NJ 08873 (United States); School of Engineering, Rutgers University, Piscataway, NJ 08854 (United States)

    2004-09-01

    Blue high brightness light emitting diodes (HB-LEDs) have been developed using different growth modes in the active layers. Piezoelectric field engineering improves the optical output power in multiple quantum well (MQW) LEDs by inserting an optimized transitional superlattice (TSL) before the active MQW layers. Within single quantum well (SQW) LEDs, quasi-Quantum Dot (QD) growth for Indium localization has been realized. The SQW LED output power exceeds the strain engineered MQW LEDs. The experimental data indicates that Indium localization enhances overall quantum efficiency and results in increased output power for HB-LEDs. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. A novel phytomyxean parasite associated with galls on the bull-kelp Durvillaea antarctica (Chamisso) Hariot.

    Science.gov (United States)

    Goecke, Franz; Wiese, Jutta; Núñez, Alejandra; Labes, Antje; Imhoff, Johannes F; Neuhauser, Sigrid

    2012-01-01

    Durvillaea antarctica (Fucales, Phaeophyceae) is a large kelp of high ecological and economic significance in the Southern Hemisphere. In natural beds along the central coast of Chile (Pacific Ocean), abnormal growth characterized by evident gall development and discolorations of the fronds/thallus was observed. Analysing these galls by light microscopy and scanning electron microscopy revealed the presence of endophytic eukaryotes showing typical characteristics for phytomyxean parasites. The parasite developed within enlarged cells of the subcortical tissue of the host. Multinucleate plasmodia developed into many, single resting spores. The affiliation of this parasite to the Phytomyxea (Rhizaria) was supported by 18S rDNA data, placing it within the Phagomyxida. Similar microorganisms were already reported once 23 years ago, indicating that these parasites are persistent and widespread in D. antarctica beds for long times. The symptoms caused by this parasite are discussed along with the ecological and economic consequences. Phytomyxean parasites may play an important role in the marine ecosystem, but they remain understudied in this environment. Our results demonstrate for the first time the presence of resting spores in Phagomyxida, an order in which resting spores were thought to be absent making this the first record of a phagomyxean parasite with a complete life cycle so far, challenging the existing taxonomic concepts within the Phytomyxea. The importance of the here described resting spores for the survival and ecology of the phagomyxid parasite will be discussed together with the impact this parasite may have on 'the strongest seaweed of the world', which is an important habitat forming and economic resource from the Southern Hemisphere.

  13. A novel phytomyxean parasite associated with galls on the bull-kelp Durvillaea antarctica (Chamisso Hariot.

    Directory of Open Access Journals (Sweden)

    Franz Goecke

    Full Text Available Durvillaea antarctica (Fucales, Phaeophyceae is a large kelp of high ecological and economic significance in the Southern Hemisphere. In natural beds along the central coast of Chile (Pacific Ocean, abnormal growth characterized by evident gall development and discolorations of the fronds/thallus was observed. Analysing these galls by light microscopy and scanning electron microscopy revealed the presence of endophytic eukaryotes showing typical characteristics for phytomyxean parasites. The parasite developed within enlarged cells of the subcortical tissue of the host. Multinucleate plasmodia developed into many, single resting spores. The affiliation of this parasite to the Phytomyxea (Rhizaria was supported by 18S rDNA data, placing it within the Phagomyxida. Similar microorganisms were already reported once 23 years ago, indicating that these parasites are persistent and widespread in D. antarctica beds for long times. The symptoms caused by this parasite are discussed along with the ecological and economic consequences. Phytomyxean parasites may play an important role in the marine ecosystem, but they remain understudied in this environment. Our results demonstrate for the first time the presence of resting spores in Phagomyxida, an order in which resting spores were thought to be absent making this the first record of a phagomyxean parasite with a complete life cycle so far, challenging the existing taxonomic concepts within the Phytomyxea. The importance of the here described resting spores for the survival and ecology of the phagomyxid parasite will be discussed together with the impact this parasite may have on 'the strongest seaweed of the world', which is an important habitat forming and economic resource from the Southern Hemisphere.

  14. THE SUSTAINABLE DEVELOPMENT OF THE BRASOV GROWTH POLE

    Directory of Open Access Journals (Sweden)

    Aida CATANA

    2016-12-01

    Full Text Available The demographic dynamics analysed in the context of the relationship between economic development and social inclusion presents an image of the sustainable development of a community as well as the manner how the financial resources have been used. With an allocation of 74.3 million euro in the programming period 2007-2013, the Brasov Growth Pole has pursued the contribution to the achievement of sustainable development since 2005 by the participation in the Agenda 21. The implementation of projects with European financing in areas such as transport, social and educational infrastructure or tourism have generated changes/demographic movements, which this paper proposes to present. The evolution of the stable population, its dynamics at the level of each locality that is part of the Brasov growth pole as well as the dynamics of the number of employees or the development of the unemployment rate are presented by the cluster analysis. The effects of the European financing obtained from Regional Operational Programme 2007-2013 are thus reflected in the sustainable development of the Brasov growth pole from the point of view of the dynamics of the population

  15. Convergent development of a parasitoid wasp on three host species with differing mass and growth potential

    NARCIS (Netherlands)

    Harvey, J.A.; Molina, A.C.; Bezemer, T.M.; Malcicka, M.

    2015-01-01

    Koinobiont parasitoids develop in hosts that continue feeding and growing during the course of parasitism. Here, we compared development of a solitary koinobiont endoparasitoid, Meteorus pulchricornis Westmael (Hymenoptera: Braconidae), in second (L2) and fourth (L4) instars of three host species

  16. Intestinal parasite infections in immigrant children in the city of Rome, related risk factors and possible impact on nutritional status

    Directory of Open Access Journals (Sweden)

    Manganelli Laura

    2012-11-01

    Full Text Available Abstract Background Parasitic diseases can represent a social and economic problem among disadvantaged people - even in developed countries. Due to the limited data available concerning Europe, the aims of the present study were to evaluate the presence of parasites in immigrant children and the risk factors favouring the spread of parasites. Subsequently, the possible correlation between nutritional status and parasitic infections was also investigated. Findings A convenience sample of two hundred and forty seven immigrant children (aged 0–15 attending the Poliambulatorio della Medicina Solidale in Rome was examined. Data were collected using structured questionnaires, and parasitological and anthropometric tests were applied. Chi-squared test and binary logistic multiple-regression models were used for statistical analysis. Thirty-seven children (15% tested positive to parasites of the following species: Blastocystis hominis, Entamoeba coli, Giardia duodenalis, Enterobius vermicularis, Ascaris lumbricoides and Strongyloides stercoralis. A monospecific infection was detected in 30 (81% out of 37 parasitized children, while the others (19% presented a polyparasitism. The major risk factors were housing, i.e. living in shacks, and cohabitation with other families (p Conclusions This study shows that parasite infection in children is still quite common, even in a developed country and that children’s growth and parasitism may be related. Extensive improvements in the living, social and economic conditions of immigrants are urgently needed in order to overcome these problems.

  17. Parasites and poverty: the case of schistosomiasis.

    Science.gov (United States)

    King, Charles H

    2010-02-01

    Simultaneous and sequential transmission of multiple parasites, and their resultant overlapping chronic infections, are facts of life in many underdeveloped rural areas. These represent significant but often poorly measured health and economic burdens for affected populations. For example, the chronic inflammatory process associated with long-term schistosomiasis contributes to anaemia and undernutrition, which, in turn, can lead to growth stunting, poor school performance, poor work productivity, and continued poverty. To date, most national and international programs aimed at parasite control have not considered the varied economic and ecological factors underlying multi-parasite transmission, but some are beginning to provide a coordinated approach to control. In addition, interest is emerging in new studies for the re-evaluation and recalibration of the health burden of helminthic parasite infection. Their results should highlight the strong potential of integrated parasite control in efforts for poverty reduction. Copyright 2009 Elsevier B.V. All rights reserved.

  18. RNA trafficking in parasitic plant systems

    Science.gov (United States)

    LeBlanc, Megan; Kim, Gunjune; Westwood, James H.

    2012-01-01

    RNA trafficking in plants contributes to local and long-distance coordination of plant development and response to the environment. However, investigations of mobile RNA identity and function are hindered by the inherent difficulty of tracing a given molecule of RNA from its cell of origin to its destination. Several methods have been used to address this problem, but all are limited to some extent by constraints associated with accurately sampling phloem sap or detecting trafficked RNA. Certain parasitic plant species form symplastic connections to their hosts and thereby provide an additional system for studying RNA trafficking. The haustorial connections of Cuscuta and Phelipanche species are similar to graft junctions in that they are able to transmit mRNAs, viral RNAs, siRNAs, and proteins from the host plants to the parasite. In contrast to other graft systems, these parasites form connections with host species that span a wide phylogenetic range, such that a high degree of nucleotide sequence divergence may exist between host and parasites and allow confident identification of most host RNAs in the parasite system. The ability to identify host RNAs in parasites, and vice versa, will facilitate genomics approaches to understanding RNA trafficking. This review discusses the nature of host–parasite connections and the potential significance of host RNAs for the parasite. Additional research on host–parasite interactions is needed to interpret results of RNA trafficking studies, but parasitic plants may provide a fascinating new perspective on RNA trafficking. PMID:22936942

  19. RNA trafficking in parasitic plant systems

    Directory of Open Access Journals (Sweden)

    Megan L LeBlanc

    2012-08-01

    Full Text Available RNA trafficking in plants contributes to local and long-distance coordination of plant development and response to the environment. However, investigations of mobile RNA identity and function are hindered by the inherent difficulty of tracing a given molecule of RNA from its cell of origin to its destination. Several methods have been used to address this problem, but all are limited to some extent by constraints associated with accurately sampling phloem sap or detecting trafficked RNA. Certain parasitic plant species form symplastic connections to their hosts and thereby provide an additional system for studying RNA trafficking. The haustorial connections of Cuscuta and Phelipanche species are similar to graft junctions in that they are able to transmit mRNAs, viral RNAs, siRNAs and proteins from the host plants to the parasite. In contrast to other graft systems, these parasites form connections with host species that span a wide phylogenetic range, such that a high degree of nucleotide sequence divergence may exist between host and parasites and allow confident identification of most host RNAs in the parasite system. The ability to identify host RNAs in parasites, and vice versa, will facilitate genomics approaches to understanding RNA trafficking. This review discusses the nature of host parasite connections and the potential significance of host RNAs for the parasite. Additional research on host-parasite interactions is needed to interpret results of RNA trafficking studies, but parasitic plants may provide a fascinating new perspective on RNA trafficking.

  20. BUILDING NEW BUSINESS MODELS FOR SUSTAINABLE GROWTH AND DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Taco C. R. van Someren

    2011-06-01

    Full Text Available Considered are issues of methodology and methods, as well as ideology of strategic innovation. Using the tools of this approach is offered as mechanisms to develop and build business models for sustainable socio-economic economic growth and development of different regions. The connection between key problems of sustainable development and management policy of different economic entities is studied. The consultancy company Ynnovate’s experience in addressing these issues in the EU and China is shown. It is offered to the use its experience and tools in exploring the areas of cross-border economic cooperation between territories of the Russian Far East and China

  1. Decapentaplegic and growth control in the developing Drosophila wing.

    Science.gov (United States)

    Akiyama, Takuya; Gibson, Matthew C

    2015-11-19

    As a central model for morphogen action during animal development, the bone morphogenetic protein 2/4 (BMP2/4)-like ligand Decapentaplegic (Dpp) is proposed to form a long-range signalling gradient that directs both growth and pattern formation during Drosophila wing disc development. While the patterning role of Dpp secreted from a stripe of cells along the anterior-posterior compartmental boundary is well established, the mechanism by which a Dpp gradient directs uniform cell proliferation remains controversial and poorly understood. Here, to determine the precise spatiotemporal requirements for Dpp during wing disc development, we use CRISPR-Cas9-mediated genome editing to generate a flippase recognition target (FRT)-dependent conditional null allele. By genetically removing Dpp from its endogenous stripe domain, we confirm the requirement of Dpp for the activation of a downstream phospho-Mothers against dpp (p-Mad) gradient and the regulation of the patterning targets spalt (sal), optomotor blind (omb; also known as bifid) and brinker (brk). Surprisingly, however, third-instar wing blade primordia devoid of compartmental dpp expression maintain relatively normal rates of cell proliferation and exhibit only mild defects in growth. These results indicate that during the latter half of larval development, the Dpp morphogen gradient emanating from the anterior-posterior compartment boundary is not directly required for wing disc growth.

  2. Periconceptional growth hormone treatment alters fetal growth and development in lambs.

    Science.gov (United States)

    Koch, J M; Wilmoth, T A; Wilson, M E

    2010-05-01

    Research in the area of fetal programming has focused on intrauterine growth restriction. Few studies have attempted to examine programming mechanisms that ultimately lead to lambs with a greater potential for postnatal growth. We previously demonstrated that treatment of ewes with GH at the time of breeding led to an increase in birth weight. Therefore, the objective of this study was to determine the effects of a single injection of sustained-release GH given during the periconceptional period on fetal growth and development and to determine if the GH axis would be altered in these offspring. Estrus was synchronized using 2 injections of PGF(2alpha); at the time of the second injection, ewes assigned to treatment were also given an injection of sustained-release GH. A maternal jugular vein sample was taken weekly to analyze IGF-I as a proxy for GH to estimate the duration of the treatment effect. In ewes treated with GH, IGF-I increased (P brain weights were obtained, as well as left and right ventricular wall thicknesses. On postnatal d 100, a subset of ewe lambs were weighed and challenged with an intravenous injection of GHRH. Lambs from treated ewes had increased (P left ventricular wall was thinner (P development. Lambs born to ewes treated with GH were larger at birth and had altered organ development, which may indicate that early maternal GH treatment may lead to permanent changes in the developing fetus. The ewe lambs maintained their growth performance to at least 100 d of postnatal life and appeared to have an altered GH axis, as demonstrated by the altered response to GHRH.

  3. Tongue Growth during Prenatal Development in Korean Fetuses and Embryos

    Directory of Open Access Journals (Sweden)

    Soo Jeong Hong

    2015-11-01

    Full Text Available Background: Prenatal tongue development may affect oral-craniofacial structures, but this muscular organ has rarely been investigated. Methods: In order to document the physiology of prenatal tongue growth, we histologically examined the facial and cranial base structures of 56 embryos and 106 fetuses. Results: In Streeter’s stages 13–14 (fertilization age [FA], 28 to 32 days, the tongue protruded into the stomodeal cavity from the retrohyoid space to the cartilaginous mesenchyme of the primitive cranial base, and in Streeter’s stage 15 (FA, 33 to 36 days, the tongue rapidly swelled and compressed the cranial base to initiate spheno-occipital synchondrosis and continued to swell laterally to occupy most of the stomodeal cavity in Streeter’s stage 16–17 (FA, 37 to 43 days. In Streeter’s stage 18–20 (FA, 44 to 51 days, the tongue was vertically positioned and filled the posterior nasopharyngeal space. As the growth of the mandible and maxilla advanced, the tongue was pulled down and protruded anteriorly to form the linguomandibular complex. Angulation between the anterior cranial base (ACB and the posterior cranial base (PCB was formed by the emerging tongue at FA 4 weeks and became constant at approximately 124°–126° from FA 6 weeks until birth, which was consistent with angulations measured on adult cephalograms. Conclusions: The early clockwise growth of the ACB to the maxillary plane became harmonious with the counter-clockwise growth of the PCB to the tongue axis during the early prenatal period. These observations suggest that human embryonic tongue growth affects ACB and PCB angulation, stimulates maxillary growth, and induces mandibular movement to achieve the essential functions of oral and maxillofacial structures.

  4. Impact of accelerated plant growth on seed variety development

    Science.gov (United States)

    Christophersen, Eric

    1998-01-01

    The commercial lives of agricultural seed products have steadily declined in recent years. The introduction of genetically engineered crop seeds in 1966 has accentuated that trend. Widespread grower demand for genetically engineered seed requires competitive response by industry followers in order to avert market share losses to the industry leaders. Limitations on plant transformation technology, regulatory requirements and patent impediments require companies to rapidly convert transformed lines into elite commercial products. Massive multigenerational backcrossing efforts are required to distribute genetically engineered traits into a broad product mix. Significant incidents of expression failures, or ``gene silencing,'' have occurred unexpectedly, requiring product substitution strategies. First-to-market strategies, competitive response, broad germplasm conversion and rescue of product failures all share the element of urgency. Technologies which reliably accelerate product development rates can expect favorable reception by commercial seed developers. A growth chamber which dramatically accelerates the rate of plant growth is described.

  5. Development of silicon growth techniques from melt with surface heating

    Science.gov (United States)

    Kravtsov, Anatoly

    2018-05-01

    The paper contains literary and personal data on the development history of silicon-growing technology with volumetric and surface melt heating. It discusses the advantages and disadvantages of surface-heating technology. Examples are given of the implementation of such processes in the 60s-70s of the last century, and the reasons for the discontinuation of the relevant work. It describes the main solutions for the implementation of crystal growth process with the electron-beam heating of the melt surface, implemented by KEPP EU (Latvia). It discusses differences in the management of the growth process for the crystals with constant diameters compared to the Czochralski method. It lists geometrical and electro-physical properties of the obtained crystals. It describes the possible use of such crystals and the immediate challenges of technology development.

  6. Effects of polymeric carbohydrates on growth and development

    DEFF Research Database (Denmark)

    Knudsen, Knud Erik Bach

    , metabolized and net energy); available energy relative to protein is crucial for performance and carcass quality; second, the proportion of starch to NSP will influence rate and type of metabolites (glucose vs. SCFA) deriving from carbohydrate assimilation, and finally, type of starch (types A, B, and C......The main objective of the presentation is to provide insight into the role of polymeric carbohydrates in growth and development of pigs. Polymeric carbohydrates—starch and non-starch polysaccharides (NSP)—quantitatively represent the largest portion of the diets for pigs and are therefore...... at a slower and more constant rate and with SCFA being absorbed by passive diffusion. Type and levels of polymeric carbohydrates influence growth and development through different mechanisms; first, the proportion of starch to NSP plays an important role for the content of available energy (digestible...

  7. Energy consumption, economic growth and prices: A reassessment using panel VECM for developed and developing countries

    International Nuclear Information System (INIS)

    Mahadevan, Renuka; Asafu-Adjaye, John

    2007-01-01

    This paper reinvestigates the energy consumption-GDP growth nexus in a panel error correction model using data on 20 net energy importers and exporters from 1971 to 2002. Among the energy exporters, there was bidirectional causality between economic growth and energy consumption in the developed countries in both the short and long run, while in the developing countries energy consumption stimulates growth only in the short run. The former result is also found for energy importers and the latter result exists only for the developed countries within this category. In addition, compared to the developing countries, the developed countries' elasticity response in terms of economic growth from an increase in energy consumption is larger although its income elasticity is lower and less than unitary. Lastly, the implications for energy policy calling for a more holistic approach are discussed

  8. Women and Parasitic Diseases

    Science.gov (United States)

    ... Consultations, and General Public. Contact Us Parasites Home Women Recommend on Facebook Tweet Share Compartir Infection with ... of parasites can lead to unique consequences for women. Some examples are given below. Infection with Toxoplasma ...

  9. Pets and Parasites

    Science.gov (United States)

    ... good news is that this rarely happens. Most pet-to-people diseases can be avoided by following a few ... your doctor Can a parasite cause death in people and pets? Can human disease from a parasite be treated ...

  10. Functional characterization of CLE peptides from a plant-parasitic nematode Globodera rostochiensis

    Science.gov (United States)

    Plant CLAVATA3/ESR (CLE) proteins are a large family of secreted peptide ligands that play important roles in plant growth and development. Recent evidence suggests that plant-parasitic cyst nematodes secrete ligand mimics of plant CLE peptides to modify selected host root cells into multinucleate f...

  11. Do multiple micronutrient interventions improve child health, growth, and development?

    Science.gov (United States)

    Ramakrishnan, Usha; Goldenberg, Tamar; Allen, Lindsay H

    2011-11-01

    Micronutrient deficiencies are common and often co-occur in many developing countries. Several studies have examined the benefits of providing multiple micronutrient (MMN) interventions during pregnancy and childhood, but the implications for programs remain unclear. The key objective of this review is to summarize what is known about the efficacy of MMN interventions during early childhood on functional outcomes, namely, child health, survival, growth, and development, to guide policy and identify gaps for future research. We identified review articles including meta-analyses and intervention studies that evaluated the benefits of MMN interventions (3 or more micronutrients) in children (growth. Two studies found no effects on child mortality. The findings for respiratory illness and diarrhea are mixed, although suggestive of benefit when provided as fortified foods. There is evidence from several controlled trials (>25) and 2 meta-analyses that MMN interventions improve hemoglobin concentrations and reduce anemia, but the effects were small compared to providing only iron or iron with folic acid. Two recent meta-analyses and several intervention trials also indicated that MMN interventions improve linear growth compared to providing a placebo or single nutrients. Much less is known about the effects on MMN interventions during early childhood on motor and mental development. In summary, MMN interventions may result in improved outcomes for children in settings where micronutrient deficiencies are widespread.

  12. Redox signaling in the growth and development of colonial hydroids.

    Science.gov (United States)

    Blackstone, Neil W

    2003-02-01

    Redox signaling provides a quick and efficient mechanism for clonal or colonial organisms to adapt their growth and development to aspects of the environment, e.g. the food supply. A 'signature' of mitochondrial redox signaling, particularly as mediated by reactive oxygen species (ROS), can be elucidated by experimental manipulation of the electron transport chain. The major sites of ROS formation are found at NADH dehydrogenase of complex I and at the interface between coenzyme Q and complex III. Inhibitors of complex III should thus upregulate ROS from both sites; inhibitors of complex I should upregulate ROS from the first but not the second site, while uncouplers of oxidative phosphorylation should downregulate ROS from both sites. To investigate the possibility of such redox signaling, perturbations of colony growth and development were carried out using the hydroid Podocoryna carnea. Oxygen uptake of colonies was measured to determine comparable physiological doses of antimycin A(1) (an inhibitor of complex III), rotenone (an inhibitor of complex I) and carbonyl cyanide m-chlorophenylhydrazone (CCCP; an uncoupler of oxidative phosphorylation). Using these doses, clear effects on colony growth and development were obtained. Treatment with antimycin A(1) results in 'runner-like' colony growth, with widely spaced polyps and stolon branches, while treatment with CCCP results in 'sheet-like' growth, with closely spaced polyps and stolon branches. Parallel results have been obtained previously with azide, an inhibitor of complex IV, and dinitrophenol, another uncoupler of oxidative phosphorylation. Perhaps surprisingly, rotenone produced effects on colony development similar to those of CCCP. Assays of peroxides using 2',7'-dichlorofluorescin diacetate and fluorescent microscopy suggest a moderate difference in ROS formation between the antimycin and rotenone treatments. The second site of ROS formation (the interface between coenzyme Q and complex III) may thus

  13. Parasites as prey

    NARCIS (Netherlands)

    Goedknegt, M.A.; Welsh, J.E.; Thieltges, D.W.

    2012-01-01

    Parasites are usually considered to use their hosts as a resource for energy. However, there is increasing awareness that parasites can also become a resource themselves and serve as prey for other organisms. Here we describe various types of predation in which parasites act as prey for other

  14. Neglected Parasitic Infections: Toxocariasis

    Centers for Disease Control (CDC) Podcasts

    This podcast is an overview of the Clinician Outreach and Communication Activity (COCA) Call: Neglected Parasitic Infections in the United States. Neglected Parasitic Infections are a group of diseases that afflict vulnerable populations and are often not well studied or diagnosed. A subject matter expert from CDC's Division of Parasitic Diseases and Malaria describes the epidemiology, diagnosis, and treatment of toxocariasis.

  15. Growth and Psychological Development in Postoperative Patients With Anterior Encephaloceles.

    Science.gov (United States)

    Dutta, Hemonta Kumar; Khangkeo, Chow Wachana; Baruah, Kaberi; Borbora, Debasish

    2017-06-01

    Anterior encephaloceles are rare malformations that are frequently associated with other brain anomalies. This study evaluates the growth and psychological development of children following encephalocele repair. Growth and psychological assessment was done in 24 children with only encephalocele (group I); nine children with encephalocele and hydrocephalus (group II); seven children with encephalocele, hydrocephalus, and secondary malformations (group III); and 40 apparently healthy control subjects. Psychological assessment was done by evaluating intelligence and temperament. Single-stage repair was performed in 38 children, and two underwent multistage repair. Major postoperative complications were noted in three individuals. The follow-up period ranged from 12 to 168 months, and during this time the growth velocity declined significantly among group II and group III patients when compared with control subjects. After adjusting the body mass index for age, our data revealed that group III participants had a significantly (P = 0.02) lower body mass index than the control group. Group III also had poor indices for intelligence quotient (P ≤ 0.01) and temperament (P ≤ 0.01). Female patients had lower temperament indices when compared with unaffected females with regard to approach withdrawal (P ≤ 0.01), mood (P = 0.026), and intensity (P = 0.03). Overall, increased disease severity adversely affected the psychological indices. Individuals with anterior encephalocele without associated intracranial defects had excellent postoperative outcomes in terms of growth and psychological developments. Hydrocephalus and agenesis of corpus callosum had the least impact on psychological development. However, the presence of secondary brain defects led to developmental delays. Gender differences in temperament may suggest a need for distinct treatment regimens to assess psychosocial well-being for males and females. Copyright © 2017 Elsevier Inc. All rights

  16. Nigerian population growth and its implications for economic development.

    Science.gov (United States)

    Okpala, A O

    1990-12-01

    The population of Nigeria is growing at a rate of 3.75%/year indicating a doubling of the population every 22 years. Demographers estimated the population to be 91,178,000 in 1985. Even though population density is high (288 people/square mile), it is not equally distributed. It is highest in the south and southwest urban areas such as Lagos (1045 people/square mile) and lowest in the northeast (75 people/square mile). Moreover rural-urban migration is growing. A major reason for rural-urban migration is the dual nature of the economy in Nigeria. In urban areas, economic development brings about higher standards of living, but, in rural areas, a subsistence economy predominates. This coupled with rapid population growth results in small or no growth in per capita income. Only if the government were to integrate redistribution policies into complete economic development plans should it consider redistributing the population. It should stress rural development (e.g., incentives for firms to set up in rural areas). Further it should move some government offices to rural areas. The government also needs to adopt population policies encouraging the lowering of fertility levels. If it were to provide education through the secondary and prevocational education level free of charge, educated women will lower their fertility. Sex education should be included in the curriculum. Further the government must play an active role in family planning programs, especially educating rural women about family planning. It should also use the mass media to promote small family size, but it should not dictate family size. It also needs to recognize that population growth puts much pressure on the environment. For example, population growth causes soil erosion, nutrient exhaustion, rapid deforestation, and other problems which render the land unusable for agriculture.

  17. The ecology of fish parasites with particular reference to helminth parasites and their salmonid fish hosts in Welsh rivers: a review of some of the central questions.

    Science.gov (United States)

    Thomas, J D

    2002-01-01

    was positively correlated with the condition factor and the adipose index. Two testable hypotheses were advanced to explain these observations. First, the more dominant well-conditioned fish in the hierarchy are more likely to acquire parasites because they ingest more food items and spend more time in sheltered habitats with depositing sediments where transmission mainly occurs. Second, the parasites may release factors that stimulate the host's immune and endocrinological systems to produce factors that enhance somatic growth and inhibit reproduction of the host. This benign relationship is considered to be indicative of long-term coevolution. The sex of the fish had a significant influence on the abundance of the parasites in total and also on particular species with the bias in all cases being in favour of the female fish. This review shows that sex bias in parasitism is generally not strong and that male bias in parasitism is not a general rule. Taken as a whole, the results fail to support most of the predictions based on the Hamilton-Zuk and the immunocompetence hypotheses. Possible hypotheses to explain why parasitism tends to be higher in female than in male trout include testosterone immunosuppression, corticosteroid-based immune suppression and differences between the size and behaviour of the sexes. However, the latter two hypotheses have more credence, although testosterone levels are higher in female than male trout. Between the early 1950s and 1998 there has been a marked decline in the prevalence, abundance and diversity of the helminth parasite communities in salmonid fish as well as their intermediate hosts. Possible reasons for these declines include heavy metal pollution, increased acidity and habitat degradation linked to changes in land use. It is concluded that although helminth parasites can provide supplementary information on pollution. the use of biotic indices based on the Biological monitoring working party (BMWP) or River invertebrate

  18. Cultivation of Parasitic Leptospires: Effect of Pyruvate

    Science.gov (United States)

    Johnson, R. C.; Walby, J.; Henry, R. A.; Auran, N. E.

    1973-01-01

    Sodium pyruvate (100 μg/ml) is a useful addition to the Tween 80-albumin medium for the cultivation of parasitic serotypes. It is most effective in promoting growth from small inocula and growth of the nutritionally fastidious serotypes. Images PMID:4580191

  19. Systems analysis of chaperone networks in the malarial parasite Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Soundara Raghavan Pavithra

    2007-09-01

    Full Text Available Molecular chaperones participate in the maintenance of cellular protein homeostasis, cell growth and differentiation, signal transduction, and development. Although a vast body of information is available regarding individual chaperones, few studies have attempted a systems level analysis of chaperone function. In this paper, we have constructed a chaperone interaction network for the malarial parasite, Plasmodium falciparum. P. falciparum is responsible for several million deaths every year, and understanding the biology of the parasite is a top priority. The parasite regularly experiences heat shock as part of its life cycle, and chaperones have often been implicated in parasite survival and growth. To better understand the participation of chaperones in cellular processes, we created a parasite chaperone network by combining experimental interactome data with in silico analysis. We used interolog mapping to predict protein-protein interactions for parasite chaperones based on the interactions of corresponding human chaperones. This data was then combined with information derived from existing high-throughput yeast two-hybrid assays. Analysis of the network reveals the broad range of functions regulated by chaperones. The network predicts involvement of chaperones in chromatin remodeling, protein trafficking, and cytoadherence. Importantly, it allows us to make predictions regarding the functions of hypothetical proteins based on their interactions. It allows us to make specific predictions about Hsp70-Hsp40 interactions in the parasite and assign functions to members of the Hsp90 and Hsp100 families. Analysis of the network provides a rational basis for the anti-malarial activity of geldanamycin, a well-known Hsp90 inhibitor. Finally, analysis of the network provides a theoretical basis for further experiments designed toward understanding the involvement of this important class of molecules in parasite biology.

  20. Polygenic Risk, Rapid Childhood Growth, and the Development of Obesity

    Science.gov (United States)

    Belsky, Daniel W.; Moffitt, Terrie E.; Houts, Renate; Bennett, Gary G.; Biddle, Andrea K.; Blumenthal, James A.; Evans, James P.; Harrington, HonaLee; Sugden, Karen; Williams, Benjamin; Poulton, Richie; Caspi, Avshalom

    2012-01-01

    Objective To test how genomic loci identified in genome-wide association studies influence the development of obesity. Design A 38-year prospective longitudinal study of a representative birth cohort. Setting The Dunedin Multidisciplinary Health and Development Study, Dunedin, New Zealand. Participants One thousand thirty-seven male and female study members. Main Exposures We assessed genetic risk with a multilocus genetic risk score. The genetic risk score was composed of single-nucleotide polymorphisms identified in genome-wide association studies of obesity-related phenotypes. We assessed family history from parent body mass index data collected when study members were 11 years of age. Main Outcome Measures Body mass index growth curves, developmental phenotypes of obesity, and adult obesity outcomes were defined from anthropometric assessments at birth and at 12 subsequent in-person interviews through 38 years of age. Results Individuals with higher genetic risk scores were more likely to be chronically obese in adulthood. Genetic risk first manifested as rapid growth during early childhood. Genetic risk was unrelated to birth weight. After birth, children at higher genetic risk gained weight more rapidly and reached adiposity rebound earlier and at a higher body mass index. In turn, these developmental phenotypes predicted adult obesity, mediating about half the genetic effect on adult obesity risk. Genetic associations with growth and obesity risk were independent of family history, indicating that the genetic risk score could provide novel information to clinicians. Conclusions Genetic variation linked with obesity risk operates, in part, through accelerating growth in the early childhood years after birth. Etiological research and prevention strategies should target early childhood to address the obesity epidemic. PMID:22665028

  1. Methodology and application of flow cytometry for investigation of human malaria parasites.

    Science.gov (United States)

    Grimberg, Brian T

    2011-03-31

    Historically, examinations of the inhibition of malaria parasite growth/invasion, whether using drugs or antibodies, have relied on the use of microscopy or radioactive hypoxanthine uptake. These are considered gold standards for measuring the effectiveness of antimalarial treatments, however, these methods have well known shortcomings. With the advent of flow cytometry coupled with the use of fluorescent DNA stains allowed for increased speed, reproducibility, and qualitative estimates of the effectiveness of antibodies and drugs to limit malaria parasite growth which addresses the challenges of traditional techniques. Because materials and machines available to research facilities are so varied, different methods have been developed to investigate malaria parasites by flow cytometry. This review is intended to serve as a reference guide for advanced users and importantly, as a primer for new users, to support expanded use and improvements to malaria flow cytometry, particularly in endemic countries. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Malaria parasite-synthesized heme is essential in the mosquito and liver stages and complements host heme in the blood stages of infection.

    Directory of Open Access Journals (Sweden)

    Viswanathan Arun Nagaraj

    Full Text Available Heme metabolism is central to malaria parasite biology. The parasite acquires heme from host hemoglobin in the intraerythrocytic stages and stores it as hemozoin to prevent free heme toxicity. The parasite can also synthesize heme de novo, and all the enzymes in the pathway are characterized. To study the role of the dual heme sources in malaria parasite growth and development, we knocked out the first enzyme, δ-aminolevulinate synthase (ALAS, and the last enzyme, ferrochelatase (FC, in the heme-biosynthetic pathway of Plasmodium berghei (Pb. The wild-type and knockout (KO parasites had similar intraerythrocytic growth patterns in mice. We carried out in vitro radiolabeling of heme in Pb-infected mouse reticulocytes and Plasmodium falciparum-infected human RBCs using [4-(14C] aminolevulinic acid (ALA. We found that the parasites incorporated both host hemoglobin-heme and parasite-synthesized heme into hemozoin and mitochondrial cytochromes. The similar fates of the two heme sources suggest that they may serve as backup mechanisms to provide heme in the intraerythrocytic stages. Nevertheless, the de novo pathway is absolutely essential for parasite development in the mosquito and liver stages. PbKO parasites formed drastically reduced oocysts and did not form sporozoites in the salivary glands. Oocyst production in PbALASKO parasites recovered when mosquitoes received an ALA supplement. PbALASKO sporozoites could infect mice only when the mice received an ALA supplement. Our results indicate the potential for new therapeutic interventions targeting the heme-biosynthetic pathway in the parasite during the mosquito and liver stages.

  3. Role of micronutrients for physical growth and mental development.

    Science.gov (United States)

    Singh, Meharban

    2004-01-01

    Due to control of florid and severe cases of protein-energy malnutrition, deficiencies of micronutrients in children have assumed public health importance. According to National Nutrition Monitoring Bureau of India, over 50% of apparently healthy looking children have subclinical or biochemical deficiencies of vitamin A, vitamins B2, B6, folate and vitamin C. Over two-third of children have clinical evidences of iron deficiency while deficiency of trace minerals like iodine and zinc is quite common in certain populations. Children have food preferences and they are quite fussy to take green leafy vegetables and fruits thus compromising their intake of micronutrients from dietary sources. The full genetic potential of the child for physical growth and mental development may be compromised due to subclinical deficiencies of micronutrients which are commonly referred to as "hidden hunger". Micronutrients are required for the integrity and optimal functioning of immune system. Children with subclinical deficiency of micronutrients are more vulnerable to develop frequent and more severe common day-to-day infections thus triggering a vicious cycle of undernutrition and recurrent infections. A number of micronutrients are required for optimal physical growth and neuromotor development. Isolated deficiencies of micronutrients are rare in clinical practice and usually deficiencies of multiple micronutrients co-exist. The first 3 years of life are most crucial and vulnerable to the hazards of undernutrition. All efforts should be made so that preschool children are given a balanced and nutritious home-based diet. However, it has been shown that it is not possible to meet 100% requirements of recommended dietary allowances (RDA's) of micronutrients from dietary sources alone and most preschool children need administration of nutritional supplements to optimize their genetic potential for physical growth and mental development.

  4. Sustainable development and low carbon growth strategy for India

    International Nuclear Information System (INIS)

    Parikh, Kirit

    2012-01-01

    For India, sustainable strategy means one that is economically, environmentally and socially sustainable. This calls for rapid economic growth to deal with poverty and human development. However, the relatively meagre energy resources of the country pose a huge challenge. At the same time concern for climate change has raised the bar on the use of the one energy resource that India has in some abundance, namely coal. India's strategy for sustainable development has to explore all options of reducing energy needs, enhancing efficiency of use of conventional energy resources and develop new and renewable sources. The paper identifies various technical options, their potential roles and alternative policy measures to realize them in a cost effective manner. Even for the same objectives different policy instruments are available and how one chooses a particular instrument is often critical for the success. Self-implementing incentive compatible policy that does not create vested interests that would get entrenched should be preferred. -- Highlights: ► Energy efficiency is critical for sustainable development. ► India can reduce its emission intensity by 25 % by 2020 as proposed by India at Copenhagen. ► With a more aggressive effort even 35% reduction is attainable even with 8% or 9% growth. ► Energy efficient appliances, vehicles, buildings and industrial processes are needed. ► Policies that incentivize adoption of these pose critical challenges.

  5. The Use of Biofuel for Sustainable Growth in Developing Countries

    Science.gov (United States)

    Tsang, J.

    2014-12-01

    The biofuel industry is divided into four categories comprising of feedstocks used in 1st and 2nd generation bioethanol and biodiesel. In order to identify and quantify each biofuel feedstock's potential for sustainable growth, each were evaluated according to self-developed social, financial, and environmental criteria. From the investigation and analysis carried out, 1st generation biodiesel and bioethanol were determined to be feedstocks not capable of facilitating sustainable growth. Results showed low earnings before interest, taxes, depreciation and amortization (EBITDA) of -0.5 to 1 USD per gallon for biodiesel and 0.25 to 0.5 USD per gallon for bioethanol. Results also showed a poor return on asset (ROA). The energy required to produce one MJ of 1st generation biofuel fuel was at least 0.4 MJ, showing poor energy balance. Furthermore, high land, water, pesticide, and fertilizer requirements strained surrounding ecosystems by affecting the food web, thus reducing biodiversity. Over 55% of land used by the biodiesel industry in Indonesia and Malaysia involved the deforestation of local rainforests. This not only displaced indigenous organisms from their habitat and decreased their scope of nutrition, but also contributed to soil erosion and increased the probability of flooding. If left unregulated, imbalances in the ecosystem due to unsustainable growth will result in a permanent reshaping of tropical rainforest ecosystems in Southeast Asia. Algae, an example of 2nd generation biodiesel feedstock, was concluded to be the biofuel feedstock most capable of supporting sustainable growth. This is due to its low production costs of $1-1.5/gal, high biological productivity of 5000 gallons of biodiesel per acre per year, and high ROA of 25-35%. Additionally, algae's adaptability to varying environmental conditions also makes it an appealing candidate for businesses in developing countries, where access to resource supplies is unstable. Additionally, its reduced net

  6. Signalling in malaria parasites. The MALSIG consortium.

    NARCIS (Netherlands)

    Doerig, C.; Baker, D.; Billker, O.; Blackman, M.J.; Chitnis, C.; Dhar Kumar, S.; Heussler, V.; Holder, A.A.; Kocken, C.; Krishna, S.; Langsley, G.; Lasonder, E.; Menard, R.; Meissner, M.; Pradel, G.; Ranford-Cartwright, L.; Sharma, A.; Sharma, P.; Tardieux, T.; Tatu, U.; Alano, P.

    2009-01-01

    Depending on their developmental stage in the life cycle, malaria parasites develop within or outside host cells, and in extremely diverse contexts such as the vertebrate liver and blood circulation, or the insect midgut and hemocoel. Cellular and molecular mechanisms enabling the parasite to sense

  7. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

    Science.gov (United States)

    Smith, Ryan C; Vega-Rodríguez, Joel; Jacobs-Lorena, Marcelo

    2014-01-01

    Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission. PMID:25185005

  8. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

    Directory of Open Access Journals (Sweden)

    Ryan C Smith

    2014-08-01

    Full Text Available Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.

  9. Development of regional growth centres and impact on regional growth: A case study of Thailand’s Northeastern region

    Directory of Open Access Journals (Sweden)

    Nattapon Sang-arun

    2013-01-01

    Full Text Available This study investigates the spatial economic structure and inequality in Thailand at the national and regional levels, with a particular focus on the Northeastern region in the period from 1987 to 2007. The study has three main points: 1 examination of the economic structure and inequality at the national level and in the Northeastern region according to the Theil index, 2 determination of regional growth centres and satellite towns by using growth pole theory as a conceptual framework and incorporating spatial interaction analysis and 3 analysis of the relationship between regional growth centres and satellite towns with regard to the impact on growth and inequality. The results show that the Northeastern region is definitely the lagging region in the nation, by both gross domestic product (GDP and gross regional product (GRP per capita. It was therefore selected for a case study. Spatial analysis identified Nakhon Ratchasima, Khon Kaen, Udon Thani and Ubon Ratchathani as regional growth centres. Each of them has its own sphere of influence (or satellite towns, and the total area of regional growth centres and satellite towns are classified as sub-regions. The development of regional growth centres has a direct impact on sub-regional economic growth through economic and social relationships: urbanisation, industrial development, per capita growth, the number of higher educational institutes and so on. However, such growth negatively correlates with economic equality among the provinces in a sub-region. The inequality trend is obviously on an upswing. This study suggests that industrial links between regional growth centres and their satellite towns should be improved in order for regional growth centre development to have a consistently desirable effect on both economic growth and equality. Such a strong process means that the growth of regional growth centres will spread, leading to the development of their surrounding areas.

  10. Immunodiagnosis of parasitic infections using nuclear techniques

    International Nuclear Information System (INIS)

    1985-07-01

    This report documents the recommendations of the ''Advisory Group on Immunodiagnosis of Parasitic Infections Using Nuclear Techniques'' with a focus on malaria, schistosomiasis and filariasis. Radionuclide tracers are considered an important component of present and future immunological methods for the assessment of the host's humoral and cellular immunity to the parasite and the detection of parasite antigen(s) in human body fluids. The Advisory Group has concluded that there is a continuing need for the development and application of immunodiagnostic methods in parasitic diseases. This report concerns methods which are currently or potentially applicable to immunodiagnostic investigations in parasitic diseases. Reference is made, where appropriate, to recent developments in research which may lead to improvement and standardization of methods now available and the development of new methodology. Separate abstracts on various papers presented were prepared

  11. Paradigms for parasite conservation.

    Science.gov (United States)

    Dougherty, Eric R; Carlson, Colin J; Bueno, Veronica M; Burgio, Kevin R; Cizauskas, Carrie A; Clements, Christopher F; Seidel, Dana P; Harris, Nyeema C

    2016-08-01

    Parasitic species, which depend directly on host species for their survival, represent a major regulatory force in ecosystems and a significant component of Earth's biodiversity. Yet the negative impacts of parasites observed at the host level have motivated a conservation paradigm of eradication, moving us farther from attainment of taxonomically unbiased conservation goals. Despite a growing body of literature highlighting the importance of parasite-inclusive conservation, most parasite species remain understudied, underfunded, and underappreciated. We argue the protection of parasitic biodiversity requires a paradigm shift in the perception and valuation of their role as consumer species, similar to that of apex predators in the mid-20th century. Beyond recognizing parasites as vital trophic regulators, existing tools available to conservation practitioners should explicitly account for the unique threats facing dependent species. We built upon concepts from epidemiology and economics (e.g., host-density threshold and cost-benefit analysis) to devise novel metrics of margin of error and minimum investment for parasite conservation. We define margin of error as the risk of accidental host extinction from misestimating equilibrium population sizes and predicted oscillations, while minimum investment represents the cost associated with conserving the additional hosts required to maintain viable parasite populations. This framework will aid in the identification of readily conserved parasites that present minimal health risks. To establish parasite conservation, we propose an extension of population viability analysis for host-parasite assemblages to assess extinction risk. In the direst cases, ex situ breeding programs for parasites should be evaluated to maximize success without undermining host protection. Though parasitic species pose a considerable conservation challenge, adaptations to conservation tools will help protect parasite biodiversity in the face of

  12. Ecological network analysis for economic systems: growth and development and implications for sustainable development.

    Science.gov (United States)

    Huang, Jiali; Ulanowicz, Robert E

    2014-01-01

    The quantification of growth and development is an important issue in economics, because these phenomena are closely related to sustainability. We address growth and development from a network perspective in which economic systems are represented as flow networks and analyzed using ecological network analysis (ENA). The Beijing economic system is used as a case study and 11 input-output (I-O) tables for 1985-2010 are converted into currency networks. ENA is used to calculate system-level indices to quantify the growth and development of Beijing. The contributions of each direct flow toward growth and development in 2010 are calculated and their implications for sustainable development are discussed. The results show that during 1985-2010, growth was the main attribute of the Beijing economic system. Although the system grew exponentially, its development fluctuated within only a small range. The results suggest that system ascendency should be increased in order to favor more sustainable development. Ascendency can be augmented in two ways: (1) strengthen those pathways with positive contributions to increasing ascendency and (2) weaken those with negative effects.

  13. Growth and development in children born very low birthweight.

    Science.gov (United States)

    Scharf, Rebecca J; Stroustrup, Annemarie; Conaway, Mark R; DeBoer, Mark D

    2016-09-01

    To examine the relationships between growth (birth to age 2 years) and developmental outcomes in children born with very low birthweight (VLBW). Motor and mental development in children born with VLBW were regressed on anthropometric measurements at birth, 9 months and 2 years using multivariable regression. The Early Childhood Longitudinal Study-Birth Cohort, a longitudinal cohort, community sample, designed to be representative of children born across the USA. 950 children born with VLBW (children exhibited poor growth, with length-for-age z-scores children at 9 months (adjusted for prematurity) and 34.2% of children at 2 years. Compared with children having z-scores >-2, children with growth shortfalls in head circumference, length and weight had a higher adjusted OR (aOR) of low Bayley motor scores at 9 months and 2 years (aOR ranging from 1.8 to 3.3, all pchildren born with VLBW. While careful length measures may be a particularly useful marker, deficits in all anthropometric measures were risk factors for developmental delays. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  14. Congenital hypothyroidism: etiology and growth-development outcome.

    Science.gov (United States)

    Dalili, Setila; Rezvani, Seyed Mahmood; Dalili, Hossein; Mohtasham Amiri, Zahra; Mohammadi, Hamid; Abrisham Kesh, Sahar; Novin, Mohammad Hassan; Medghalchi, Abdolreza; Gholamnezhad, Hajar

    2014-01-01

    One of the most preventable causes of mental and growth retardation is congenital hypothyroidism (CH). This study tries to investigate growth and mental outcome of patients with CH. Since November 2006 and November 2007 in Guilan province, north of Iran, all neonates who were diagnosed with CH, evaluated for etiology of CH by laboratory follow up, thyroid sonography or scan. Growth and development of patients with CH were compared with healthy children in same age, geographical area, social and economical classes in four years old. Demographic characteristics including height, weight, and head circumference at birth, follow up time (four years old) and IQ (Good enough test) were recorded in questionnaires. Among 28904 screened neonates, 37 patients with CH were diagnosed. Incidence of CH was 1:781 in live births, 20 (54%) in female neonates and 17 (46%) in male neonates. The incidences of permanent and transient hypothyroidism were 43.2% (16 cases) and 56. 8% (21 cases) respectively. The incidence of permanent and transient hypothyroidism were 16 (43.2%) and 21 (56, 8%), respectively. In permanent CH, 11 cases (%.68.2) had dyshormonogenesis and 5 cases (%.31.2) had thyroid dysgenesis. Significant statistical difference was only in family history of thyroid disease (34, 3% Positive family history in CH vs. 13.2% in control group, P-value 0.03). All other demographic characteristics and IQ had no statistical difference. Patients with CH diagnosed through neonatal screening and treated had normal growth as general population that indicates effective screening program and treatment in this area (3.2%).

  15. Development and validation of an extensive growth and growth boundary model for psychrotolerant Lactobacillus spp. in seafood and meat products

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Dalgaard, Paw

    2013-01-01

    A new and extensive growth and growth boundary model for psychrotolerant Lactobacillus spp. was developed and validated for processed and unprocessed products of seafood and meat. The new model was developed by refitting and expanding an existing cardinal parameter model for growth and the growth...... of psychrotolerant Lactobacillus spp. was clearly demonstrated. The new model can be used to predict growth of psychrotolerant Lactobacillus spp. in seafood and meat products e.g. prediction of the time to a critical cell concentration of bacteria is considered useful for establishing the shelf life. In addition...... boundary of lactic acid bacteria (LAB) in processed seafood (O. Mejlholm and P. Dalgaard, J. Food Prot. 70. 2485–2497, 2007). Initially, to estimate values for the maximum specific growth rate at the reference temperature of 25°C (μref) and the theoretical minimum temperature that prevents growth...

  16. Gene expression during ovarian differentiation in parasitic and non-parasitic lampreys: implications for fecundity and life history types.

    Science.gov (United States)

    Spice, Erin K; Whyard, Steven; Docker, Margaret F

    2014-11-01

    Lampreys diverged from the jawed vertebrate lineage approximately 500million years ago. Lampreys undergo sex differentiation much later than most other vertebrates, and ovarian differentiation occurs several years before testicular differentiation. The genetic basis of lamprey sex differentiation is of particular interest both because of the phylogenetic importance of lampreys and because of their unusual pattern of sex differentiation. As well, differences between parasitic and non-parasitic lampreys may first become evident at ovarian differentiation. However, nothing is known about the genetic basis of ovarian differentiation in lampreys. This study examined potential differences in gene expression before, during, and after ovarian differentiation in parasitic chestnut lamprey Ichthyomyzon castaneus and non-parasitic northern brook lamprey Ichthyomyzonfossor. Eight target genes (17β-hydroxysteroid dehydrogenase, germ cell-less, estrogen receptor β, insulin-like growth factor 1 receptor, daz-associated protein 1, cytochrome c oxidase subunit III, Wilms' tumour suppressor protein 1, and dehydrocholesterol reductase 7) were examined. Northern brook lamprey displayed higher expression of cytochrome c oxidase subunit III, whereas chestnut lamprey displayed higher expression of insulin-like growth factor 1 receptor; these genes may be involved in apoptosis and oocyte growth, respectively. Presumptive male larvae had higher expression of Wilms' tumour suppressor protein 1, which may be involved in the undifferentiated gonad and/or later testicular development. Differentiated females had higher expression of 17β hydroxysteroid dehydrogenase and daz-associated protein 1, which may be involved in female development. This study is the first to identify genes that may be involved in ovarian differentiation and fecundity in lampreys. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Paternity-parasitism trade-offs: a model and test of host-parasite cooperation in an avian conspecific brood parasite.

    Science.gov (United States)

    Lyon, Bruce E; Hochachka, Wesley M; Eadie, John M

    2002-06-01

    Efforts to evaluate the evolutionary and ecological dynamics of conspecific brood parasitism in birds and other animals have focused on the fitness costs of parasitism to hosts and fitness benefits to parasites. However, it has been speculated recently that, in species with biparental care, host males might cooperate with parasitic females by allowing access to the host nest in exchange for copulations. We develop a cost-benefit model to explore the conditions under which such host-parasite cooperation might occur. When the brood parasite does not have a nest of her own, the only benefit to the host male is siring some of the parasitic eggs (quasi-parasitism). Cooperation with the parasite is favored when the ratio of host male paternity of his own eggs relative to his paternity of parasitic eggs exceeds the cost of parasitism. When the brood parasite has a nest of her own, a host male can gain additional, potentially more important benefits by siring the high-value, low-cost eggs laid by the parasite in her own nest. Under these conditions, host males should be even more likely to accept parasitic eggs in return for copulations with the parasitic female. We tested these predictions for American coots (Fulica americana), a species with a high frequency of conspecific brood parasitism. Multilocus DNA profiling indicated that host males did not sire any of the parasitic eggs laid in host nests, nor did they sire eggs laid by the parasite in her own nest. We used field estimates of the model parameters from a four-year study of coots to predict the minimum levels of paternity required for the costs of parasitism to be offset by the benefits of mating with brood parasites. Observed levels of paternity were significantly lower than those predicted under a variety of assumptions, and we reject the hypothesis that host males cooperated with parasitic females. Our model clarifies the specific costs and benefits that influence host-parasite cooperation and, more generally

  18. Effects of stocking density on growth performance, feather growth, intestinal development, and serum parameters of geese.

    Science.gov (United States)

    Yin, L Y; Wang, Z Y; Yang, H M; Xu, L; Zhang, J; Xing, H

    2017-09-01

    This experiment was conducted to evaluate the effects of stocking density on the growth performance, feather growth, intestinal development, and serum parameters of geese. In total, 336 healthy, 28-day-old, male Yangzhou goslings were randomly allotted to 30 plastic wire-floor pens according to 5 stocking densities (2, 3, 4, 5 and 6 birds/m2). The results showed that with the stocking density increased from 2 birds/m2 to 6 birds/m2, the body weights of geese at 42 d (P density was increased to 6 birds/m2. Serum concentrations of alkaline phosphatase (P = 0.013) and triiodothyronine (P density increased. The serum thyroxine concentration of geese from the 6 birds/m2 group was lower than that of geese from the other groups (P density will adversely influence thyroid function and the developments of the body weight, body size, feathers, and small intestine. Under our experimental conditions, we recommend that the stocking density of geese should be kept to 5 or fewer birds/m2 to avoid the negative effects of high stocking density on geese. © 2017 Poultry Science Association Inc.

  19. Parasitism and calfhood diseases.

    Science.gov (United States)

    Herlich, H; Douvres, F W

    1977-02-01

    That animals can and do acquire an effective immunity against helminth parasites has been demonstrated extensively experimentally, and the fact that domestic animals such as cattle, sheep, and horses become adults while maintaining good health in spite of constant exposure to reinfection long has suggested that immunity must be important to such survival. Although our attempts to date to vaccinate calves against helminth parasites have either failed or been unsatisfactory because of the pathosis induced by the experimental vaccines, the results are not surprising or discouraging. In contrast to the long history of immunization research on bacterial and viral diseases, only within a relatively short time have serious efforts been directed at exploiting hostal immunity for prevention and control of helminthic diseases. Unlike the comparatively simple structures of viruses and bacteria, helminths are complex multicellular animals with vast arrays of antigens and complicated physiological and immunological interactions with their hosts. Much more fundamental information on helminth-bovine interactions, on helminth antigens, and on cattle antibody systems must be developed before progress on control of cattle helminths by vaccination can be meaningful.

  20. Development Of Biosteres sp Parasitation On Larvae Of Bactrocera carambolae (Drew and Hancock) As Complementary Of Sterile Insect Technique

    International Nuclear Information System (INIS)

    Sikumbang, Darmawi; Nasution, Indah A.; Indarwatmi, M.; Kuswadi, Achmad N.

    2002-01-01

    Sterile insect technique was compatible with biological control after parasitoid releasing. In order to find out suitable life stage of B. carambolae to use as host in the mass rearing of Biosteres sp. parasitoid, an efectivity of the parasitoid infestation on different age of B. carambolae egg by putting fruits in cage containing 200 pairs of B. carambolae flies for the 1 hour. The fruit of infected fruit fly larvae with the different age i.e. 1,2,3, and 4 days were offered to 80 pairs of adult pamsitoid age 1,2, and 3 weeks for old for two hours i.e. 7.00-9.00; 9.00- 11.00; 11.00-13.00; 13.00-15.00; and 15.00-17.00. Numbers of parasitoid emerge from each fruit were observed. Results of the parasitation effectiveness assays show that 1-2 days old larvae were the most severely infested larvae infestation by the done at 7-15 of the day by the day parasitoid. Infestation mostly done by parasitoid of 7-14 days old

  1. Bilateral asymmetry of the humerus during growth and development.

    Science.gov (United States)

    Blackburn, Amanda

    2011-08-01

    The development of handedness throughout growth can be investigated by using bilateral asymmetry of the humerus as a proxy for this trait. A large skeletal sample of nonadults from English archaeological sites was examined using standard metric techniques to assess when right-sided asymmetry first appears in the human skeleton. Results of this work indicate a change in directional asymmetry during growth and development, with infants and young children exhibiting no significant asymmetry and older children and adolescents demonstrating right-sidedness. This trend is consistent with what has been observed in previous studies of upper limb asymmetry in skeletal material and behaviorally in living children, adding further strength to the premise that biomechanical forces strongly influence bilateral asymmetry in the upper limb bones. Variability in the magnitude of asymmetry between different features of the humerus was also noted. This characteristic can be explained by differing degrees of genetic canalization, with length and articular dimensions being more strongly canalized than diaphyseal properties. Copyright © 2011 Wiley-Liss, Inc.

  2. Taxes and Economic Growth in Developing Countries : A Dynamic Panel Approach

    OpenAIRE

    NANTOB, N'Yilimon

    2014-01-01

    This paper looks at the effects of taxes increase on economic growth of 47 developing countries. In developing countries, there is no magic tax strategy to encourage economic growth. Some countries with high tax burdens have high growth rates and some countries with low tax burdens have low growth rates. Despite much theoretical and empirical inquiry as well as political and policy controversy, no simple answer exists concerning the relationship of taxes on economic growth in developing count...

  3. Growth with pollution: unsustainable development in Taiwan and its consequences.

    Science.gov (United States)

    Chi, C C

    1994-01-01

    Mutually supportive relationships between the Koumington (KMT) government and the private economic sector in Taiwan foster economic growth, which is incompatible with environmental protection. Environmental degradation in Taiwan is due almost exclusively to rapid economic growth; Taiwan should not be used as an example for developing countries. Taiwan's economic success was made possible because it did not have restrictions on pollution that its trading partners did. Air pollution reports in 1989 amounted to about 24 cases per day of appeals to environmental agencies country-wide. Major urban pollution sources include car, motorcycle, and industrial emissions. Acts passed in 1975 and 1982 have had little impact. Water pollution is caused by domestic sewage (25%), industrial waste water (54%), and domestic animal waste (21%). Untreated sewage in the water contributes to a high rate of hepatitis. Soil contamination is due to industrial development and agricultural intensification. Hazardous waste is dumped in the countryside; 3000 people in 1986 were poisoned by PCB-contaminated waste. Noise pollution standards are set at 60 decibels in residential areas and 65 decibels outside residential areas, but most find these levels too high. Industrial and toxic waste amounted in 1988 to 57,499 tons per day or 50% of Japan's volume. Waste is freely dumped into the air, water, and land. The food chain has been affected, and occupational diseases and cancer have doubled in 30 years. Deforestation on steep slopes contributes to serious soil erosion and fresh water resources problems. Economic growth maintains political legitimacy, sustains relationships between the government and the capitalist elites, and contributes to its monopoly of economic activities. The KMT government control of enterprises increased from 1 to 94 between the 1970s and 1986, while production by public enterprises declined over the same period. The Environmental Protection Agency has not been effective

  4. Apicomplexa-specific tRip facilitates import of exogenous tRNAs into malaria parasites.

    Science.gov (United States)

    Bour, Tania; Mahmoudi, Nassira; Kapps, Delphine; Thiberge, Sabine; Bargieri, Daniel; Ménard, Robert; Frugier, Magali

    2016-04-26

    The malaria-causing Plasmodium parasites are transmitted to vertebrates by mosquitoes. To support their growth and replication, these intracellular parasites, which belong to the phylum Apicomplexa, have developed mechanisms to exploit their hosts. These mechanisms include expropriation of small metabolites from infected host cells, such as purine nucleotides and amino acids. Heretofore, no evidence suggested that transfer RNAs (tRNAs) could also be exploited. We identified an unusual gene in Apicomplexa with a coding sequence for membrane-docking and structure-specific tRNA binding. This Apicomplexa protein-designated tRip (tRNA import protein)-is anchored to the parasite plasma membrane and directs import of exogenous tRNAs. In the absence of tRip, the fitness of the parasite stage that multiplies in the blood is significantly reduced, indicating that the parasite may need host tRNAs to sustain its own translation and/or as regulatory RNAs. Plasmodium is thus the first example, to our knowledge, of a cell importing exogenous tRNAs, suggesting a remarkable adaptation of this parasite to extend its reach into host cell biology.

  5. Deposit growth and property development in coal-fired furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L. [Sandia National Lab., Livermore, CA (United States)

    1995-11-01

    The objectives of this research project are: (1) to provide a self-consistent database of simultaneously measured, time-resolved ash deposit properties in well-controlled and well-defined environments and (2) to provide analytical expressions that relate deposit composition and structure to deposit properties of immediate relevance to PETC`s Combustion 2000 program. This project is distinguished from related work being done elsewhere by: (1) the development and deployment of in-situ diagnostics to monitor deposit properties, including heat transfer coefficients, porosity, emissivity, tenacity, strength, density, and viscosity; (2) the time resolution of such properties during deposit growth; (3) simultaneous measurement of structural and composition properties; (4) development of algorithms from a self-consistent, simultaneously measured database that includes the interdependence of properties; and (5) application of the results to technologically relevant environments such as those being planned under Combustion 2000 program. Work completed during FY94 emphasized diagnostic development. During FY95, this development work will be completed and we will emphasize application of the diagnostics to meet the other project objectives. Included in this work are the development and application of two in-situ, real-time diagnostic systems for monitoring the properties of inorganic materials on Heat transfer surfaces and in the gas-phase during controlled combustion of selected coal samples in Sandia`s Multifuel Combustor (MFC). Also, several diagnostics are being incorporated into the MFC that will eventually be used to characterize ash deposit properties.

  6. Foodborne parasites from wildlife

    DEFF Research Database (Denmark)

    Kapel, Christian Moliin Outzen; Fredensborg, Brian Lund

    2015-01-01

    The majority of wild foods consumed by humans are sourced from intensively managed or semi-farmed populations. Management practices inevitably affect wildlife density and habitat characteristics, which are key elements in the transmission of parasites. We consider the risk of transmission...... of foodborne parasites to humans from wildlife maintained under natural or semi-natural conditions. A deeper understanding will be useful in counteracting foodborne parasites arising from the growing industry of novel and exotic foods....

  7. Parasites, Plants, and People.

    Science.gov (United States)

    Johnson, Marion; Moore, Tony

    2016-06-01

    Anthelminthic resistance is acknowledged worldwide and is a major problem in Aotearoa New Zealand, thus alternative parasite management strategies are imperative. One Health is an initiative linking animal, human, and environmental health. Parasites, plants, and people illustrate the possibilities of providing diverse diets for stock thereby lowering parasite burdens, improving the cultural wellbeing of a local community, and protecting the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Burden of non-sexually transmitted infections on adolescent growth and development in the developing world.

    Science.gov (United States)

    Di Pentima, Cecilia

    2009-12-01

    A vast majority of children living in developing countries face their teen years following a childhood of malnutrition and limited access to education and health care. In this environment of disadvantages, exposure to old and reemerging infections become a significant determinant of their likelihood to overcome poverty: tuberculosis and its rapid progression during adolescence may anticipate a premature death; malaria, as well as its debilitating recurrent febrile episodes and anemia, is responsible for most of their lost time at school or work. Furthermore, the burden of anemia and malnutrition is aggravated by infestation with common intestinal worms such as with hookworms, Trichuris trichiura and Ascaris lumbricoides. These parasites compete for iron and nutrients and produce mucosal damage and inflammation causing anorexia and worsening the intake and absorption of their marginal diets. Other infections among the many neglected tropical infectious diseases, many others common to adolescents in developed countries, and some that could be controlled by access to vaccines, add scores against the physical and intellectual fitness of millions of teens in tropical developing countries.

  9. Parasitism shaping host life-history evolution

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2006-01-01

    1. Variation in life-history strategies among conspecific populations indicates the action of local selective pressures; recently, parasitism has been suggested as one of these local forces. 2. Effects of trematode infections on reproductive effort, juvenile growth, size at maturity and susceptib......1. Variation in life-history strategies among conspecific populations indicates the action of local selective pressures; recently, parasitism has been suggested as one of these local forces. 2. Effects of trematode infections on reproductive effort, juvenile growth, size at maturity...

  10. Decades of urban growth and development on the Asian megadeltas

    Science.gov (United States)

    Small, Christopher; Sousa, Daniel; Yetman, Gregory; Elvidge, Christopher; MacManus, Kytt

    2018-06-01

    The current and ongoing expansion of urban areas worldwide represents the largest mass migration in human history. It is well known that the world's coastal zones are associated with large and growing concentrations of population, urban development and economic activity. Among coastal environments, deltas have long been recognized for both benefits and hazards. This is particularly true on the Asian megadeltas, where the majority of the world's deltaic populations reside. Current trends in urban migration, combined with demographic momentum suggest that the already large populations on the Asian megadeltas will continue to grow. In this study, we combine recently released gridded population density (circa 2010) with a newly developed night light change product (1992 to 2012) and a digital elevation model to quantify the spatial distribution of population and development on the nine Asian megadeltas. Bivariate distributions of population as functions of elevation and coastal proximity quantify potential exposure of deltaic populations to flood and coastal hazards. Comparison of these distributions for the Asian megadeltas show very different patterns of habitation with peak population elevations ranging from 2 to 11 m above sea level over a wide range of coastal proximities. Over all nine megadeltas, over 174 million people reside below a peak population elevation of 7 m. Changes in the spatial extent of anthropogenic night light from 1992 to 2012 show widely varying extents and changes of lighted urban development. All of the deltas except the Indus show the greatest increases in night light brightness occurring at elevations <10 m. At global and continental scales, growth of settlements of all sizes takes the form of evolving spatial networks of development. Spatial networks of lighted urban development in Asia show power law scaling properties consistent with other continents, but much higher rates of growth. The three largest networks of development in China all

  11. Development of radiation utilization for economic growth in China

    International Nuclear Information System (INIS)

    Lu Yanxiao

    1994-01-01

    The program of radiation utilization in China was initiated with the development of nuclear industry in the late 1950s. From then on, the establishment of relatively comprehensive nuclear industrial system and a fair number of talent technical personnel have laid the foundation for radiation utilization in industry, agriculture, medicine and so on. Radioisotopes and radiation become one of the most effective means for acquiring data and information and changing material properties in modern techniques. They are, in many respects, unique and cannot replaced by other techniques. In recent years the considerable progress in the development, commercialization and large-scale utilization of radioisotopes and radiation has been creating economic and social benefits for Chinese modernization. The applications in agriculture have mainly embodied in mutation breeding of crops and so on through radiation or in combination with other methods to provide excellent mutant varieties. The important applications in medicine are the medical diagnosis with radioimmunoassay (RIA) and radiopharmaceutical imaging, and cancer therapy with radioisotopes and electron beam. Well-established methods have bee offered for routine clinic applications to help to heal the patients and rescue the lives. The industrial applications are of key importance in economic growth in China. In fact, radiation processing and nucleonic control systems (NCS) for industrial utilization are very useful to technological transformation of Chinese traditional industries. The radiation utilization in industries can be emerging as new high-tech industries. A fuller exploitation of radiation utilization is expected to meet the requirements of high growth of national economy and to bridge the gap between China and the developed countries in the world in nuclear application. (author)

  12. Regional growth and atlasing of the developing human brain.

    Science.gov (United States)

    Makropoulos, Antonios; Aljabar, Paul; Wright, Robert; Hüning, Britta; Merchant, Nazakat; Arichi, Tomoki; Tusor, Nora; Hajnal, Joseph V; Edwards, A David; Counsell, Serena J; Rueckert, Daniel

    2016-01-15

    Detailed morphometric analysis of the neonatal brain is required to characterise brain development and define neuroimaging biomarkers related to impaired brain growth. Accurate automatic segmentation of neonatal brain MRI is a prerequisite to analyse large datasets. We have previously presented an accurate and robust automatic segmentation technique for parcellating the neonatal brain into multiple cortical and subcortical regions. In this study, we further extend our segmentation method to detect cortical sulci and provide a detailed delineation of the cortical ribbon. These detailed segmentations are used to build a 4-dimensional spatio-temporal structural atlas of the brain for 82 cortical and subcortical structures throughout this developmental period. We employ the algorithm to segment an extensive database of 420 MR images of the developing brain, from 27 to 45weeks post-menstrual age at imaging. Regional volumetric and cortical surface measurements are derived and used to investigate brain growth and development during this critical period and to assess the impact of immaturity at birth. Whole brain volume, the absolute volume of all structures studied, cortical curvature and cortical surface area increased with increasing age at scan. Relative volumes of cortical grey matter, cerebellum and cerebrospinal fluid increased with age at scan, while relative volumes of white matter, ventricles, brainstem and basal ganglia and thalami decreased. Preterm infants at term had smaller whole brain volumes, reduced regional white matter and cortical and subcortical grey matter volumes, and reduced cortical surface area compared with term born controls, while ventricular volume was greater in the preterm group. Increasing prematurity at birth was associated with a reduction in total and regional white matter, cortical and subcortical grey matter volume, an increase in ventricular volume, and reduced cortical surface area. Copyright © 2015 The Authors. Published by

  13. Development of radiation utilization for economic growth in China

    Energy Technology Data Exchange (ETDEWEB)

    Yanxiao, Lu [China Nuclear Information Center, Beijing, BJ (China)

    1994-01-01

    The program of radiation utilization in China was initiated with the development of nuclear industry in the late 1950s. From then on, the establishment of relatively comprehensive nuclear industrial system and a fair number of talent technical personnel have laid the foundation for radiation utilization in industry, agriculture, medicine and so on. Radioisotopes and radiation become one of the most effective means for acquiring data and information and changing material properties in modern techniques. They are, in many respects, unique and cannot replaced by other techniques. In recent years the considerable progress in the development, commercialization and large-scale utilization of radioisotopes and radiation has been creating economic and social benefits for Chinese modernization. The applications in agriculture have mainly embodied in mutation breeding of crops and so on through radiation or in combination with other methods to provide excellent mutant varieties. The important applications in medicine are the medical diagnosis with radioimmunoassay (RIA) and radiopharmaceutical imaging, and cancer therapy with radioisotopes and electron beam. Well-established methods have bee offered for routine clinic applications to help to heal the patients and rescue the lives. The industrial applications are of key importance in economic growth in China. In fact, radiation processing and nucleonic control systems (NCS) for industrial utilization are very useful to technological transformation of Chinese traditional industries. The radiation utilization in industries can be emerging as new high-tech industries. A fuller exploitation of radiation utilization is expected to meet the requirements of high growth of national economy and to bridge the gap between China and the developed countries in the world in nuclear application. (author).

  14. Neglected Parasitic Infections: Toxocariasis

    Centers for Disease Control (CDC) Podcasts

    2012-01-05

    This podcast is an overview of the Clinician Outreach and Communication Activity (COCA) Call: Neglected Parasitic Infections in the United States. Neglected Parasitic Infections are a group of diseases that afflict vulnerable populations and are often not well studied or diagnosed. A subject matter expert from CDC's Division of Parasitic Diseases and Malaria describes the epidemiology, diagnosis, and treatment of toxocariasis.  Created: 1/5/2012 by Center for Global Health, Division of Parasitic Diseases and Malaria (DPDM); Emergency Risk Communication Branch (ERCB)/Joint Information Center (JIC), Office of Public Health Preparedness and Response (OPHPR).   Date Released: 1/9/2012.

  15. A life cycle database for parasitic acanthocephalans, cestodes, and nematodes

    Science.gov (United States)

    Benesh, Daniel P.; Lafferty, Kevin D.; Kuris, Armand

    2017-01-01

    Parasitologists have worked out many complex life cycles over the last ~150 years, yet there have been few efforts to synthesize this information to facilitate comparisons among taxa. Most existing host-parasite databases focus on particular host taxa, do not distinguish final from intermediate hosts, and lack parasite life-history information. We summarized the known life cycles of trophically transmitted parasitic acanthocephalans, cestodes, and nematodes. For 973 parasite species, we gathered information from the literature on the hosts infected at each stage of the parasite life cycle (8510 host-parasite species associations), what parasite stage is in each host, and whether parasites need to infect certain hosts to complete the life cycle. We also collected life-history data for these parasites at each life cycle stage, including 2313 development time measurements and 7660 body size measurements. The result is the most comprehensive data summary available for these parasite taxa. In addition to identifying gaps in our knowledge of parasite life cycles, these data can be used to test hypotheses about life cycle evolution, host specificity, parasite life-history strategies, and the roles of parasites in food webs.

  16. Developing a dynamic growth model for teak plantations in India

    Directory of Open Access Journals (Sweden)

    Vindhya Prasad Tewari

    2014-05-01

    Full Text Available Background Tectona grandis (teak is one of the most important tropical timber speciesoccurring naturally in India. Appropriate growth models, based on advanced modeling techniques,are not available but are necessary for the successful management of teak stands in the country.Long-term forest planning requires mathematical models, and the principles of Dynamical SystemTheory provide a solid foundation for these. Methods The state-space approach makes it possible to accommodate disturbances and avarying environment. In this paper, an attempt has been made to develop a dynamic growthmodel based on the limited data, consisting of three annual measurements, collected from 22 teak sample plots in Karnataka, Southern India. Results A biologically consistent whole-stand growth model has been presented which uses thestate-space approach for modelling rates of change of three state-variables viz., dominant height,stems per hectare and stand basal area. Moreover, the model includes a stand volume equationas an output function to estimate this variable at any point in time. Transition functions werefitted separately and simultaneously. Moreover, a continuous autoregressive error structure isalso included in the modelling process. For fitting volume equation, generalized method of moments was used to get efficient parameter estimates under heteroscedastic conditions. Conclusions A simple model containing few free parameters performed well and is particularlywell suited to situations where available data is scarce.

  17. Symbiotic regulation of plant growth, development and reproduction

    Science.gov (United States)

    Rodriguez, R.J.; Freeman, D. Carl; McArthur, E.D.; Kim, Y.-O.; Redman, R.S.

    2009-01-01

    The growth and development of rice (Oryzae sativa) seedlings was shown to be regulated epigenetically by a fungal endophyte. In contrast to un-inoculated (nonsymbiotic) plants, endophyte colonized (symbiotic) plants preferentially allocated resources into root growth until root hairs were well established. During that time symbiotic roots expanded at five times the rate observed in nonsymbiotic plants. Endophytes also influenced sexual reproduction of mature big sagebrush (Artemisia tridentata) plants. Two spatially distinct big sagebrush subspecies and their hybrids were symbiotic with unique fungal endophytes, despite being separated by only 380 m distance and 60 m elevation. A double reciprocal transplant experiment of parental and hybrid plants, and soils across the hybrid zone showed that fungal endophytes interact with the soils and different plant genotypes to confer enhanced plant reproduction in soil native to the endophyte and reduced reproduction in soil alien to the endophyte. Moreover, the most prevalent endophyte of the hybrid zone reduced the fitness of both parental subspecies. Because these endophytes are passed to the next generation of plants on seed coats, this interaction provides a selective advantage, habitat specificity, and the means of restricting gene flow, thereby making the hybrid zone stable, narrow and potentially leading to speciation. ?? 2009 Landes Bioscience.

  18. (macro- Evolutionary ecology of parasite diversity: From determinants of parasite species richness to host diversification

    Directory of Open Access Journals (Sweden)

    Serge Morand

    2015-04-01

    Full Text Available The present review summarized the factors or determinants that may explain parasite diversity among host species and the consequences of this parasite diversity on the evolution of host-life history traits. As host–parasite interactions are asymmetrical exploited–exploiter relationships, ecological and epidemiological theories produce hypotheses to find the potential determinants of parasite species richness, while life-history theory helps for testing potential consequences on parasite diversity on the evolution of hosts. This review referred only to studies that have specifically controlled or took into account phylogenetic information illustrated with parasites of mammals. Several points needing more investigation were identified with a special emphasis to develop the metabolic theory of epidemiology.

  19. Growth patterns in children with intrauterine growth retardation and their correlation to neurocognitive development.

    Science.gov (United States)

    Fattal-Valevski, Aviva; Toledano-Alhadef, Hagit; Leitner, Yael; Geva, Ronny; Eshel, Rina; Harel, Shaul

    2009-07-01

    The relationship between somatic growth and neurocognitive outcome was studied in a cohort of 136 children with intrauterine growth retardation. The children were followed up from birth to 9 to 10 years of age by annual measurements of growth parameters, neurodevelopmental evaluations, and IQ. The rate of catch-up for height between 1 and 2 years of age was significantly higher than the catch-up for weight (P importance for prediction of subsequent neurodevelopmental outcome in children with intrauterine growth retardation.

  20. Subversion of complement by hematophagous parasites.

    Science.gov (United States)

    Schroeder, Hélène; Skelly, Patrick J; Zipfel, Peter F; Losson, Bertrand; Vanderplasschen, Alain

    2009-01-01

    The complement system is a crucial part of innate and adaptive immunity which exerts a significant evolutionary pressure on pathogens. It has selected for those pathogens, mainly microorganisms but also parasites, that have evolved countermeasures. The characterization of how pathogens evade complement attack is a rapidly developing field of current research. In recent years, multiple complement evasion strategies have been characterized. In this review, we focus on complement escape mechanisms expressed by hematophagous parasites, a heterogeneous group of metazoan parasites that share the property of ingesting the whole blood of their host. Complement inhibition is crucial for parasite survival within the host tissue or to facilitate blood feeding. Finally, complement inhibition by hematophagous parasites may also contribute to their success as pathogen vectors.

  1. Fetal, neonatal, infant, and child international growth standards: an unprecedented opportunity for an integrated approach to assess growth and development.

    Science.gov (United States)

    Garza, Cutberto

    2015-07-01

    The recent publication of fetal growth and gestational age-specific growth standards by the International Fetal and Newborn Growth Consortium for the 21st Century Project and the previous publication by the WHO of infant and young child growth standards based on the WHO Multicentre Growth Reference Study enable evaluations of growth from ∼9 wk gestation to 5 y. The most important features of these projects are the prescriptive approach used for subject selection and the rigorous testing of the assertion that growth is very similar among geographically and ethnically diverse nonisolated populations when health, nutrition, and other care needs are met and the environment imposes minimal constraints on growth. Both studies documented that with adequate controls, the principal source of variability in growth during gestation and early childhood resides among individuals. Study sites contributed much less to observed variability. The agreement between anthropometric measurements common to both studies also is noteworthy. Jointly, these studies provide for the first time, to my knowledge, a conceptually consistent basis for worldwide and localized assessments and comparisons of growth performance in early life. This is an important contribution to improving the health care of children across key periods of growth and development, especially given the appropriate interest in pursuing "optimal" health in the "first 1000 d," i.e., the period covering fertilization/implantation, gestation, and postnatal life to 2 y of age. © 2015 American Society for Nutrition.

  2. Nuclear Research and Development Capabilities Needed to Support Future Growth

    Energy Technology Data Exchange (ETDEWEB)

    Wham, Robert M. [ORNL, P.O. Box 2008, Oak Ridge, TN 37831-6154 (United States); Kearns, Paul [Battelle Memorial Institute (United States); Marston, Ted [Marston Consulting (United States)

    2009-06-15

    The energy crisis looming before the United States can be resolved only by an approach that integrates a 'portfolio' of options. Nuclear energy, already an important element in the portfolio, should play an even more significant role in the future as the U.S. strives to attain energy independence and reduce carbon emissions. The DOE Office of Nuclear Energy asked Battelle Memorial Institute to obtain input from the commercial power generation industry on industry's vision for nuclear energy over the next 30-50 years. With this input, Battelle was asked to generate a set of research and development capabilities necessary for DOE to support the anticipated growth in nuclear power generation. This presentation, based on the report generated for the Office of Nuclear Energy, identifies the current and future nuclear research and development capabilities required to make this happen. The capabilities support: (1) continued, safe operation of the current fleet of nuclear plants; (2) the availability of a well qualified and trained workforce; (3) demonstration of the next generation nuclear plants; (4) development of a sustainable fuel cycle; (5) advanced technologies for maximizing resource utilization and minimization of waste and (6) advanced modeling and simulation for rapid and reliable development and deployment of new nuclear technologies. In order to assure these capabilities are made available, a Strategic Nuclear Energy Capability Initiative is proposed to provide the required resources during this critical period of time. (authors)

  3. Parasitic nematode interactions with mammals and plants.

    Science.gov (United States)

    Jasmer, Douglas P; Goverse, Aska; Smant, Geert

    2003-01-01

    Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent reinfection of host species. In addition, development of resistance to nematicides and anthelmintics by these parasites and reduced availability of some nematicides, for environmental protection, pose significant obstacles for current and future prospects of effective parasite control. Due to marked differences in host species, research on animal and plant parasitic nematodes often proceeds independently. Despite the differences between animals and plants, basic cellular properties are shared among these host organisms. Some common properties may be important for mechanisms [homologous or convergent (homoplastic)] by which nematodes successfully infect these diverse hosts or by which animal and plant hosts resist infections by these pathogens. Here we compare host/parasite interactions between plant parasitic nematodes (PPN) and animal parasitic nematodes, with an emphasis on mammalian hosts (MPN). Similarities and differences are considered in the context of progress on molecular dissection of these interactions. A comprehensive coverage is not possible in the space allotted. Instead, an illustrative approach is used to establish examples that, it is hoped, exemplify the value of the comparative approach.

  4. New mechanisms of disease and parasite-host interactions.

    Science.gov (United States)

    de Souza, Tiago Alves Jorge; de Carli, Gabriel Jose; Pereira, Tiago Campos

    2016-09-01

    An unconventional interaction between a patient and parasites was recently reported, in which parasitic cells invaded host's tissues, establishing several tumors. This finding raises various intriguing hypotheses on unpredicted forms of interplay between a patient and infecting parasites. Here we present four unusual hypothetical host-parasite scenarios with intriguing medical consequences. Relatively simple experimental designs are described in order to evaluate such hypotheses. The first one refers to the possibility of metabolic disorders in parasites intoxicating the host. The second one is on possibility of patients with inborn errors of metabolism (IEM) being more resistant to parasites (due to accumulation of toxic compounds in the bloodstream). The third one refers to a mirrored scenario: development of tumors in parasites due to ingestion of host's circulating cancer cells. The last one describes a complex relationship between parasites accumulating a metabolite and supplying it to a patient with an IEM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Does moving up a food chain increase aggregation in parasites?

    Science.gov (United States)

    Lester, R J G; McVinish, R

    2016-05-01

    General laws in ecological parasitology are scarce. Here, we evaluate data on numbers of fish parasites published by over 200 authors to determine whether acquiring parasites via prey is associated with an increase in parasite aggregation. Parasite species were grouped taxonomically to produce 20 or more data points per group as far as possible. Most parasites that remained at one trophic level were less aggregated than those that had passed up a food chain. We use a stochastic model to show that high parasite aggregation in predators can be solely the result of the accumulation of parasites in their prey. The model is further developed to show that a change in the predators feeding behaviour with age may further increase parasite aggregation. © 2016 The Author(s).

  6. The young athlete: challenges of growth, development, and society.

    Science.gov (United States)

    Bergeron, Michael F

    2010-01-01

    Youth sports provide numerous health-enhancing and other important benefits to participating children and adolescents. However, the motivations and goals of young athletes often conflict with those of adult stakeholders, and they are redirected. The youth sports industry has become exclusionary, as the professional model of development increasingly is prevalent and accepted. Youth who follow this model often cannot keep up with the unrealistic expectations and excessive demands. Too much play, training, travel, and pressure frequently lead to a variety of physical and psychological problems, particularly concurrent with the vulnerability of a young athlete going through pre- or early adolescence and the rapid growth phase. The need for alternative models, emphasizing fun and fundamentals, is becoming increasingly clear and urgent. With appropriate changes, youth sports once again can be an effective entry point for a lifetime of healthy sports participation and enjoyment.

  7. Growth and development in children with classic congenital adrenal hyperplasia.

    Science.gov (United States)

    Bonfig, Walter

    2017-02-01

    Final height outcome in classic congenital adrenal hyperplasia (CAH) has been of interest for many years. With analysis of growth patterns and used glucocorticoid regimens, enhanced treatment strategies have been developed and are still under development. Most of the current reports on final height outcome are confirmative of previous results. Final height data is still reported in cohorts that were diagnosed clinically and not by newborn screening. Clinical diagnosis of CAH leads to delayed diagnosis especially of simple virilizing CAH with significantly advanced bone age resulting in early pubertal development and reduced final height. In contrast salt-wasting CAH is diagnosed at an earlier stage in most cases resulting in better final height outcome in some cohorts. Nevertheless, final height outcome in patients with CAH treated with glucocorticoids is lower than the population norm and also at the lower end of genetic potential. Achievement of regular adult height is still a challenge with conventional glucocorticoid treatment in patients with CAH, which is why new hydrocortisone formulations and new treatment options for CAH are underway.

  8. Development and melt growth of novel scintillating halide crystals

    Science.gov (United States)

    Yoshikawa, Akira; Yokota, Yuui; Shoji, Yasuhiro; Kral, Robert; Kamada, Kei; Kurosawa, Shunsuke; Ohashi, Yuji; Arakawa, Mototaka; Chani, Valery I.; Kochurikhin, Vladimir V.; Yamaji, Akihiro; Andrey, Medvedev; Nikl, Martin

    2017-12-01

    Melt growth of scintillating halide crystals is reviewed. The vertical Bridgman growth technique is still considered as very popular method that enables production of relatively large and commercially attractive crystals. On the other hand, the micro-pulling-down method is preferable when fabrication of small samples, sufficient for preliminary characterization of their optical and/or scintillation performance, is required. Moreover, bulk crystal growth is also available using the micro-pulling-down furnace. The examples of growths of various halide crystals by industrially friendly melt growth techniques including Czochralski and edge-defined film-fed growth methods are also discussed. Finally, traveling molten zone growth that in some degree corresponds to horizontal zone melting is briefly overviewed.

  9. PARASITES OF FISH

    Science.gov (United States)

    The intent of this chapter is to describe the parasites of importance to fishes maintained and used in laboratory settings. In contrast to the frist edition, the focus will be only on those parasites that pose a serious threat to or are common in fishes held in these confined en...

  10. Parasites from the Past

    DEFF Research Database (Denmark)

    Søe, Martin Jensen; Fredensborg, Brian Lund; Nejsum, Peter

    will investigate how the diversity of food-borne parasitic infections has changed with cultural and dietary habits, hunting practice and intensity of animal husbandry. This is done by isolating and typing ancient DNA remains from parasite eggs found in archeological samples from across Denmark....

  11. Interactions between microbial agents and gypsy moth parasites

    Science.gov (United States)

    Ronald M. Weseloh

    1985-01-01

    The parasite Cotesia melanoscelus attacks small gypsy moth larvae more successfully than large ones, and Bacillus thuringiensis retards the growth of caterpillars it does not kill. Together, both factors lead to higher parasitism by C. melanoscelus in areas sprayed with B. thuringiensis than...

  12. Intrauterine Growth Restriction Alters Mouse Intestinal Architecture during Development.

    Science.gov (United States)

    Fung, Camille M; White, Jessica R; Brown, Ashley S; Gong, Huiyu; Weitkamp, Jörn-Hendrik; Frey, Mark R; McElroy, Steven J

    2016-01-01

    Infants with intrauterine growth restriction (IUGR) are at increased risk for neonatal and lifelong morbidities affecting multiple organ systems including the intestinal tract. The underlying mechanisms for the risk to the intestine remain poorly understood. In this study, we tested the hypothesis that IUGR affects the development of goblet and Paneth cell lineages, thus compromising the innate immunity and barrier functions of the epithelium. Using a mouse model of maternal thromboxane A2-analog infusion to elicit maternal hypertension and resultant IUGR, we tested whether IUGR alters ileal maturation and specifically disrupts mucus-producing goblet and antimicrobial-secreting Paneth cell development. We measured body weights, ileal weights and ileal lengths from birth to postnatal day (P) 56. We also determined the abundance of goblet and Paneth cells and their mRNA products, localization of cellular tight junctions, cell proliferation, and apoptosis to interrogate cellular homeostasis. Comparison of the murine findings with human IUGR ileum allowed us to verify observed changes in the mouse were relevant to clinical IUGR. At P14 IUGR mice had decreased ileal lengths, fewer goblet and Paneth cells, reductions in Paneth cell specific mRNAs, and decreased cell proliferation. These findings positively correlated with severity of IUGR. Furthermore, the decrease in murine Paneth cells was also seen in human IUGR ileum. IUGR disrupts the normal trajectory of ileal development, particularly affecting the composition and secretory products of the epithelial surface of the intestine. We speculate that this abnormal intestinal development may constitute an inherent "first hit", rendering IUGR intestine susceptible to further injury, infection, or inflammation.

  13. Growth and psychomotor development of patients with Duchenne muscular dystrophy.

    Science.gov (United States)

    Sarrazin, Elisabeth; von der Hagen, Maja; Schara, Ulrike; von Au, Katja; Kaindl, Angela M

    2014-01-01

    Duchenne muscular dystrophy (DMD) is one of the most common hereditary degenerative neuromuscular diseases and caused by mutations in the dystrophin gene. The objective of the retrospective study was to describe growth and psychomotor development of patients with DMD and to detect a possible genotype-phenotype correlation. Data from 263 patients with DMD (mean age 7.1 years) treated at the Departments of Pediatric Neurology in three German University Hospitals was assessed with respect to body measurements (length, weight, body mass index BMI, head circumference OFC), motor and cognitive development as well as genotype (site of mutation). Anthropometric measures and developmental data were compared to those of a reference population and deviations were analyzed for their frequency in the cohort as well as in relation to the genotypes. Corticosteroid therapy was implemented in 29 from 263 patients. Overall 30% of the patients exhibit a short statue (length development at 2-5 years of age, and this is even more prevalent when steroid therapy is applied (45% of patients with steroid therapy). The BMI shows a rightwards shift (68% > 50th centile) and the OFC a leftwards shift (65% development is delayed in a third of the patients (mean age at walking 18.3 months, 30% > 18 months, 8% > 24 months). Almost half of the patients show cognitive impairment (26% learning disability, 17% intellectual disability). Although there is no strict genotype-phenotype correlation, particularly mutations in the distal part of the dystrophin gene are frequently associated with short stature and a high rate of microcephaly as well as cognitive impairment. Copyright © 2013 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  14. Growth and development of infants with asymptomatic congenital cytomegalovirus infection.

    Science.gov (United States)

    Shan, Ruobing; Wang, Xiaoliang; Fu, Ping

    2009-10-31

    To observe changes in audiology, intellectual development, behavior development, and physical growth during systematic follow-up of infants with asymptomatic congenital human cytomegalovirus (HCMV) infection. Fifty-two infants diagnosed with asymptomatic congenital HCMV infection from July 2003 to July 2007 served as the infection group, and 21 healthy infants served as the control group. All infants were confirmed to have HCMV infection by Fluorescent Quantative polymerase chain reaction (FQ-PCR). In both the infection and control groups, the neonates and infants at 3 months, 6 months, and 1 year of age underwent examinations. 1) 20 items of National Black Nurses Association (NBNA) scores of neonates 12-14 days after birth in 2 groups were 38.3 +/- 1.95 and 38.5 +/- 2.29, without significant differences. 2) Auditory test: 50 ears of 25 cases in the infection group showed abnormal auditory thresholds in V waves with an abnormal rate of 14%, while no abnormalities were found in 21 cases in the control group. 3) Mental and psychomotor development index scores in the control group (107.49 +/- 11.31 and 107.19 +/- 10.98) were compared with those in 41 asymptomatically infected infants at 1 year of age (107.21 +/- 9.96 and 108.31 +/- 11.25), and no statistically significant difference was noted. 1) An elevated threshold in the V wave was present in asymptomatically infected infants, but could not be detected through otoacoustic emission (OAE) screening. 2) Either in the neonatal or infant periods, asymptomatic congenital HCMV infection did not have a significant influence on nervous behavior or on physical and intellectual development.

  15. Wealth and well-being, economic growth, and integral development.

    Science.gov (United States)

    Bunge, Mario

    2012-01-01

    This essay tackles a bimillenary problem in psychology, ethics, economics, and political philosophy: that of the relations between wealth and well-being. What are they, and should we live for pleasure, or rather seek to live a full and useful life? This is the ancient dilemma between hedonism, the cult of pleasure, and eudemonism, the search for a good life. Economists, almost without exception, have opted for hedonism, but they have not found out what percentage of the goods that ordinary people want are not merchandises. This gap is currently being filled by psychologists, sociologists, socioeconomists, and other workers in the new "science of happiness". Their main finding, that happiness is not for sale, might surprise the orthodox economists. On the social level, the former problem, concerning individuals, gets translated into the question of national development: what kind of development should we seek, and for whom? In particular, should economic growth be prioritized, or should we promote the simultaneous development of all sectors of society, including the political and cultural? In either case, should development benefit the chosen few or everybody? And should it enhance the well-being of the individual and make that of her offspring possible? This problem, of course, lies at the intersection of three sciences--psychology, economics, and political science--and two chapters of philosophy--ethics and political philosophy. Consequently, anyone daring to propose original solutions to the problem in question will risk being criticized by experts distributed among these five fields, who are not used to talking to one another.

  16. Inevitability of Genetic Parasites

    Science.gov (United States)

    Iranzo, Jaime; Puigbò, Pere; Lobkovsky, Alexander E.; Wolf, Yuri I.

    2016-01-01

    Abstract Almost all cellular life forms are hosts to diverse genetic parasites with various levels of autonomy including plasmids, transposons and viruses. Theoretical modeling of the evolution of primordial replicators indicates that parasites (cheaters) necessarily evolve in such systems and can be kept at bay primarily via compartmentalization. Given the (near) ubiquity, abundance and diversity of genetic parasites, the question becomes pertinent: are such parasites intrinsic to life? At least in prokaryotes, the persistence of parasites is linked to the rate of horizontal gene transfer (HGT). We mathematically derive the threshold value of the minimal transfer rate required for selfish element persistence, depending on the element duplication and loss rates as well as the cost to the host. Estimation of the characteristic gene duplication, loss and transfer rates for transposons, plasmids and virus-related elements in multiple groups of diverse bacteria and archaea indicates that most of these rates are compatible with the long term persistence of parasites. Notably, a small but non-zero rate of HGT is also required for the persistence of non-parasitic genes. We hypothesize that cells cannot tune their horizontal transfer rates to be below the threshold required for parasite persistence without experiencing highly detrimental side-effects. As a lower boundary to the minimum DNA transfer rate that a cell can withstand, we consider the process of genome degradation and mutational meltdown of populations through Muller’s ratchet. A numerical assessment of this hypothesis suggests that microbial populations cannot purge parasites while escaping Muller’s ratchet. Thus, genetic parasites appear to be virtually inevitable in cellular organisms. PMID:27503291

  17. Disease dynamics in a specialized parasite of ant societies

    DEFF Research Database (Denmark)

    Andersen, Sandra Breum; Ferrari, Matthew; Evans, Harry C.

    2012-01-01

    Coevolution between ant colonies and their rare specialized parasites are intriguing, because lethal infections of workers may correspond to tolerable chronic diseases of colonies, but the parasite adaptations that allow stable coexistence with ants are virtually unknown. We explore the trade......-offs experienced by Ophiocordyceps parasites manipulating ants into dying in nearby graveyards. We used field data from Brazil and Thailand to parameterize and fit a model for the growth rate of graveyards. We show that parasite pressure is much lower than the abundance of ant cadavers suggests...

  18. Financial development and economic growth nexus in Russia

    Directory of Open Access Journals (Sweden)

    Shigeki Ono

    2017-09-01

    Full Text Available This paper examines the finance-growth nexus in Russia with the vector autoregression model, taking oil prices and foreign exchange rates into account. The analyzed period is from 1999 through 2008 (Subperiod 1 and from 2009 through 2014 (Subperiod 2. The results for Subperiod 1 suggest that there is causality from economic growth to money supply and bank lending, which implies demand-following responses. The results for Subperiod 2 show that economic growth Granger causes bank lending while there is no causality from money supply to economic growth, which could be related to the dramatic decrease in the amount of intervention in foreign exchange markets.

  19. One Health: parasites and beyond.

    Science.gov (United States)

    Blake, Damer P; Betson, Martha

    2017-01-01

    ://www.bsp.uk.net/home/) was focused on One Health, running under the title 'One Health: parasites and beyond…'. The meeting, held at the Royal Veterinary College (RVC) in Camden, London from September 14th to 15th, drew upon a blend of specialist parasitology reinforced with additional complementary expertise. Scientists, advocates, policy makers and industry representatives were invited to present at the meeting, promoting and developing One Health understanding with relevance to parasitology. The decision to widen the scope of the meeting to non-parasitological, but informative topics, is reflected in the diversity of the articles included in this special issue. A key feature of the meeting was encouragement of early career scientists, with more than 35% of the delegates registered as students and 25 posters.

  20. Spontaneous growth in growth hormone deficiency from birth until 7 years of age: development of disease-specific growth curves.

    Science.gov (United States)

    Mayer, M; Schmitt, K; Kapelari, K; Frisch, H; Köstl, G; Voigt, M

    2010-01-01

    Little is known about spontaneous growth of growth hormone (GH)-deficient children during infancy and childhood. Retrospectively, we calculated disease-specific pretreatment percentiles for height, weight, BMI and growth velocity of 113 GH-deficient boys and 41 GH-deficient girls from birth until 7 years of age, by mean and standard deviation. Infants with idiopathic GH deficiency (GHD) grow in disease-specific percentile channels. There is a significant difference in length and weight from birth onward compared to regional reference (pgrowth velocity, despite a wide variance in the first years, so height deficit became more evident with increasing age. GHD is a congenital disease no matter when height deficit becomes clinically evident, because GH-deficient children grow in disease-specific percentile channels with a highly significantly reduced length and weight, which demonstrates that GH is essential for adequate growth in infancy and early childhood. Copyright (c) 2010 S. Karger AG, Basel.

  1. Identifying energy constraints to parasite resistance.

    Science.gov (United States)

    Allen, D E; Little, T J

    2011-01-01

    Life-history theory suggests that energetically expensive traits may trade off against each other, resulting in costs associated with the development or maintenance of a particular phenotype. The deployment of resistance mechanisms during parasite exposure is one such trait, and thus their potential benefit in fighting off parasites may be offset by costs to other fitness-related traits. In this study, we used trade-off theory as a basis to test whether stimulating an increased development rate in juvenile Daphnia would reveal energetic constraints to its ability to resist infection upon subsequent exposure to the castrating parasite, Pasteuria ramosa. We show that the presumably energetically expensive process of increased development rate does result in more infected hosts, suggesting that parasite resistance requires the allocation of resources from a limited source, and thus has the potential to be costly.

  2. Development of disease-specific growth charts in Turner syndrome and Noonan syndrome

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Isojima

    2017-12-01

    Full Text Available Many congenital diseases are associated with growth failure, and patients with these diseases have specific growth patterns. As the growth patterns of affected individuals differ from those of normal populations, it is challenging to detect additional conditions that can influence growth using standard growth charts. Disease-specific growth charts are thus very useful tools and can be helpful for understanding the growth pattern and pathogenesis of congenital diseases. In addition, disease-specific growth charts allow doctors to detect deviations from the usual growth patterns for early diagnosis of an additional condition and can be used to evaluate the effects of growth-promoting treatment for patients. When developing these charts, factors that can affect the reliability of the charts should be considered. These factors include the definition of the disease with growth failure, selection bias in the measurements used to develop the charts, secular trends of the subjects, the numbers of subjects of varying ages and ethnicities, and the statistical method used to develop the charts. In this review, we summarize the development of disease-specific growth charts for Japanese individuals with Turner syndrome and Noonan syndrome and evaluate the efforts to collect unbiased measurements of subjects with these diseases. These charts were the only available disease-specific growth charts of Turner syndrome and Noonan syndrome for Asian populations and were developed using a Japanese population. Therefore, when these charts are adopted for Asian populations other than Japanese, different growth patterns should be considered.

  3. Development of disease-specific growth charts in Turner syndrome and Noonan syndrome.

    Science.gov (United States)

    Isojima, Tsuyoshi; Yokoya, Susumu

    2017-12-01

    Many congenital diseases are associated with growth failure, and patients with these diseases have specific growth patterns. As the growth patterns of affected individuals differ from those of normal populations, it is challenging to detect additional conditions that can influence growth using standard growth charts. Disease-specific growth charts are thus very useful tools and can be helpful for understanding the growth pattern and pathogenesis of congenital diseases. In addition, disease-specific growth charts allow doctors to detect deviations from the usual growth patterns for early diagnosis of an additional condition and can be used to evaluate the effects of growth-promoting treatment for patients. When developing these charts, factors that can affect the reliability of the charts should be considered. These factors include the definition of the disease with growth failure, selection bias in the measurements used to develop the charts, secular trends of the subjects, the numbers of subjects of varying ages and ethnicities, and the statistical method used to develop the charts. In this review, we summarize the development of disease-specific growth charts for Japanese individuals with Turner syndrome and Noonan syndrome and evaluate the efforts to collect unbiased measurements of subjects with these diseases. These charts were the only available disease-specific growth charts of Turner syndrome and Noonan syndrome for Asian populations and were developed using a Japanese population. Therefore, when these charts are adopted for Asian populations other than Japanese, different growth patterns should be considered.

  4. MALDI-TOF MS Profiling-Advances in Species Identification of Pests, Parasites, and Vectors

    Directory of Open Access Journals (Sweden)

    Jayaseelan Murugaiyan

    2017-05-01

    Full Text Available Invertebrate pests and parasites of humans, animals, and plants continue to cause serious diseases and remain as a high treat to agricultural productivity and storage. The rapid and accurate species identification of the pests and parasites are needed for understanding epidemiology, monitoring outbreaks, and designing control measures. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS profiling has emerged as a rapid, cost effective, and high throughput technique of microbial species identification in modern diagnostic laboratories. The development of soft ionization techniques and the release of commercial pattern matching software platforms has resulted in the exponential growth of applications in higher organisms including parasitology. The present review discusses the proof-of-principle experiments and various methods of MALDI MS profiling in rapid species identification of both laboratory and field isolates of pests, parasites and vectors.

  5. MALDI-TOF MS Profiling-Advances in Species Identification of Pests, Parasites, and Vectors.

    Science.gov (United States)

    Murugaiyan, Jayaseelan; Roesler, Uwe

    2017-01-01

    Invertebrate pests and parasites of humans, animals, and plants continue to cause serious diseases and remain as a high treat to agricultural productivity and storage. The rapid and accurate species identification of the pests and parasites are needed for understanding epidemiology, monitoring outbreaks, and designing control measures. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling has emerged as a rapid, cost effective, and high throughput technique of microbial species identification in modern diagnostic laboratories. The development of soft ionization techniques and the release of commercial pattern matching software platforms has resulted in the exponential growth of applications in higher organisms including parasitology. The present review discusses the proof-of-principle experiments and various methods of MALDI MS profiling in rapid species identification of both laboratory and field isolates of pests, parasites and vectors.

  6. The growth and development of Schistosoma mansoni in mice exposed to sublethal doses of radiation

    International Nuclear Information System (INIS)

    Aitken, R.; Wilson, R.A.

    1989-01-01

    The maturation of Schistosoma mansoni was studied in mice exposed to various sublethal doses of radiation. Although the treatment of mice with 500 rads of radiation prior to infection did not alter parasite maturation, doses in excess of 500 rads led to a reduction in worm burden. This could not be attributed to a delay in the arrival of parasites in the hepatic portal system. Worms developing in mice treated with 800 rads commenced egg-laying about 1 wk later than worms in intact mice, and the rate of egg deposition appeared to be lower in irradiated hosts. The data demonstrate that exposure of C57BL/6 mice to doses of radiation in excess of 500 rads impairs their ability to carry infections of S. mansoni. The findings do not support the hypothesis that primary worm burdens in the mouse are controlled by a host immune response

  7. Development and validation of extensive growth and growth boundary models for psychrotolerant pseudomonads in seafood, meat and vegetable products

    DEFF Research Database (Denmark)

    Martinez Rios, Veronica; Dalgaard, Paw

    Extensive growth and growth boundary models were developed and validated for psychrotolerant pseudomonads growing in seafood, meat and vegetable products. The new models were developed by expanding anexisting cardinal parameter-type model for growth of pseudomonads in milk (Martinez-Rios et al......, when observed and predicted μmax -values were compared. Thus, on average μmax -values for seafood and meat products were overestimated by 14%. Additionally, the reference growth rate parameter μref25˚C was calibrated by fitting the model to 21 μmax -values in vegetable products. This resulted in a μref......25˚C -value of 0.54 1/h. The calibrated vegetable model wassuccessfully validated using 51 μmax -values for psychrotolerant pseudomonads in vegetables. Average bias and accuracy factor values of 1.24 and 1.38 were obtained, respectively. Lag time models were developed by using relative lag times from...

  8. Efeito do sistema de manejo sobre o comportamento em pastejo, desempenho ponderal e infestação parasitária em ovinos Suffolk Effect of a management system on grazing behaviour, ponderal growth and parasitic infestation of Suffolk ewes

    Directory of Open Access Journals (Sweden)

    Eduardo Antonio da Cunha

    1997-07-01

    Full Text Available Foi estudado o comportamento em pastejo, o desempenho ponderal e o nível de infestação parasitária em ovelhas da raça Suffolk, no período de 1994 a 1995, em Nova Odessa, SP. Comparou-se dois sistemas de manejo: pastejo restrito, onde os animais foram soltos às 9:50h e presos às 17:30h e pastejo em período integral, no qual os animais não eram recolhidos, tendo a disposição abrigo para passarem a noite. Foram utilizadas 34 fêmeas adultas no verão (17 em pastejo livre e 17 em pastejo restrito e 42 fêmeas adultas no inverno (21 em pastejo livre e 21 em pastejo restrito. Trabalhou-se ainda com 12 animais traçadores em cada estação do ano, sendo metade em cada sistema de manejo visando a contagem de nematódeos no trato digestivo dos animais. Durante 3 dias consecutivos nos meses de janeiro/fevereiro (verão e julho/agosto (inverno estudou-se, através da observação dos animais, a cada 30 minutos entre as 7:00 e 17:30h, o hábito de pastejo (pastando ou não; na sombra ou no sol. Acompanhou-se o nível de infestação parasitária dos animais em cada sistema, pela contagem do OPG do rebanho e dos traçadores e nematódeos recuperados nos traçadores. Concluiu-se que a restrição do horário de pastejo isoladamente não propiciou um controle efetivo da infestação parasitária nos animais mostrando. A restrição do tempo de pastejo é compensada pela maior atividade dos animais nas horas mais quentes do dia, todavia este comportamento afetou o desempenho, resultando em menor ganho de peso. A maior disponibilidade de forragem, em relação ao consumo estimado, pode explicar a similaridade entre os tempos de pastejo verificados nos dois sistemas de manejo, tanto no verão como no inverno.Grazing behaviour, ponderal growth and level of parasitic infestation were studied in Suffolk breed sheep, from 1994 to 1995, in Nova Odessa, São Paulo. Two management systems were compared: restricted grazing, where the animals were released to

  9. Inca expansion and parasitism in the Lluta Valley: preliminary data

    Directory of Open Access Journals (Sweden)

    Santoro Calogero

    2003-01-01

    Full Text Available Assessing the impact of cultural change on parasitism has been a central goal in archaeoparasitology. The influence of civilization and the development of empires on parasitism has not been evaluated. Presented here is a preliminary analysis of the change in human parasitism associated with the Inca conquest of the Lluta Valley in Northern Chile. Changes in parasite prevalence are described. It can be seen that the change in life imposed on the inhabitants of the Lluta Valley by the Incas caused an increase in parasitism.

  10. Inca expansion and parasitism in the lluta valley: preliminary data.

    Science.gov (United States)

    Santoro, Calogero; Vinton, Sheila Dorsey; Reinhard, Karl J

    2003-01-01

    Assessing the impact of cultural change on parasitism has been a central goal in archaeoparasitology. The influence of civilization and the development of empires on parasitism has not been evaluated. Presented here is a preliminary analysis of the change in human parasitism associated with the Inca conquest of the Lluta Valley in Northern Chile. Changes in parasite prevalence are described. It can be seen that the change in life imposed on the inhabitants of the Lluta Valley by the Incas caused an increase in parasitism.

  11. Thermal time model for Egyptian broomrape ‎‎(Phelipanche aegyptiaca parasitism dynamics in carrot ‎‎(Daucus carota L.: Field validation ‎

    Directory of Open Access Journals (Sweden)

    Amnon Cochavi

    2016-12-01

    Full Text Available Carrot, a highly profitable crop in Israel, is severely damaged by Phelipanche aegyptiaca ‎parasitism. Herbicides can effectively control the parasite and prevent damage, but for ‎optimal results, knowledge about the soil-subsurface phenological stage of the parasite is ‎essential. Parasitism dynamics models have been successfully developed for the parasites P. ‎aegyptiaca, Orobanche cumana and O. minor in the summer crops, tomato, sunflower and ‎red clover, respectively. However, these models, which are based on a linear relationship ‎between thermal time and the parasitism dynamics, may not necessarily be directly ‎applicable to the P. aegyptiaca-carrot system. The objective of the current study was to ‎develop a thermal time model to predict the effect of P. aegyptiaca parasitism dynamics on ‎carrot growth. For development and validation of the models, data was collected from a ‎temperature-controlled growth experiment and from 13 plots naturally infested with P. ‎aegyptiaca in commercial carrot fields. Our results revealed that P. aegyptiaca development ‎is related to soil temperature. Moreover, unlike P. aegyptiaca parasitism in sunflower and ‎tomato, which could be predicted both a linear model, P. aegyptiaca parasitism dynamics ‎on carrot roots required a nonlinear model, due to the wider range of growth temperatures of ‎both the carrot and the parasite. Hence, two different nonlinear models were developed for ‎optimizing the prediction of P. aegyptiaca parasitism dynamics. Both models, a beta ‎function model and combined model composed of a beta function and a sigmoid curve, were ‎able to predict first P. aegyptiaca attachment. However, overall P. aegyptiaca dynamics was ‎described more accurately by the combined model (RMSE =14.58 and 10.79, respectively. ‎The results of this study will complement previous studies on P. aegyptiaca management by ‎herbicides to facilitate optimal carrot growth and

  12. Pyramidal cell development: postnatal spinogenesis, dendritic growth, axon growth, and electrophysiology.

    Directory of Open Access Journals (Sweden)

    Guy eElston

    2014-08-01

    Full Text Available Here we review recent findings related to postnatal spinogenesis, dendritic and axon growth, pruning and electrophysiology of neocortical pyramidal cells in the developing primate brain. Pyramidal cells in sensory, association and executive cortex grow dendrites, spines and axons at different rates, and vary in the degree of pruning. Of particular note is the fact that pyramidal cells in primary visual area (V1 prune more spines than they grow during postnatal development, whereas those in inferotemporal (TEO and TE and granular prefrontal cortex (gPFC; Brodmann’s area 12 grow more than they prune. Moreover, pyramidal cells in TEO, TE and the gPFC continue to grow larger dendritic territories from birth into adulthood, replete with spines, whereas those in V1 become smaller during this time. The developmental profile of intrinsic axons also varies between cortical areas: those in V1, for example, undergo an early proliferation followed by pruning and local consolidation into adulthood, whereas those in area TE tend to establish their territory and consolidate it into adulthood with little pruning. We correlate the anatomical findings with the electrophysiological properties of cells in the different cortical areas, including membrane time constant, depolarizing sag, duration of individual action potentials, and spike-frequency adaptation. All of the electrophysiological variables ramped up before 7 months of age in V1, but continued to ramp up over a protracted period of time in area TE. These data suggest that the anatomical and electrophysiological profiles of pyramidal cells vary among cortical areas at birth, and continue to diverge into adulthood. Moreover, the data reveal that the use it or lose it notion of synaptic reinforcement may speak to only part of the story, use it but you still might lose it may be just as prevalent in the cerebral cortex.

  13. Morphological development and allometric growth patterns of Acipenser persicus Borodin, 1897 (Actinopterygii, Acipenseridae during early development

    Directory of Open Access Journals (Sweden)

    Soheil Eagderi

    2017-06-01

    Full Text Available Morphological development and allometric growth patterns of reared Persian sturgeon, Acipenser persicus, were studied from hatching to 50 days post-hatching (dph. The larvae were sampled, their left sides photographed and seven morphometric characters, including total length, head length, tail length, trunk length, snout length, caudal peduncle and predorsal length were measured. Allometric growth patterns were calculated as a power function of total length and described using the growth coefficient to find important steps in early life history. The total length of the newly hatched larvae and fry were 10.59±0.8 and 38.8±2.9 mm at 1 and 50 dph, respectively. Morphogenesis and differentiation were the highest rates during the first 11 days of early development, i.e. endogenous feeding period. There were higher growth rate of head, snout and tail regions compared with those of other organs from the hatch up to yolk sac absorption, followed by positive or almost isometric patterns, after the begin of exogenous feeding, showing priority to enhance the feeding and swimming capabilities. This study confirmed that most of morphological changes of this species are occurred from hatching until the onset of exogenous feeding i.e. during the lecithotrophic phase.

  14. Smart Parasitic Nematodes Use Multifaceted Strategies to Parasitize Plants

    Directory of Open Access Journals (Sweden)

    Muhammad A. Ali

    2017-10-01

    Full Text Available Nematodes are omnipresent in nature including many species which are parasitic to plants and cause enormous economic losses in various crops. During the process of parasitism, sedentary phytonematodes use their stylet to secrete effector proteins into the plant cells to induce the development of specialized feeding structures. These effectors are used by the nematodes to develop compatible interactions with plants, partly by mimicking the expression of host genes. Intensive research is going on to investigate the molecular function of these effector proteins in the plants. In this review, we have summarized which physiological and molecular changes occur when endoparasitic nematodes invade the plant roots and how they develop a successful interaction with plants using the effector proteins. We have also mentioned the host genes which are induced by the nematodes for a compatible interaction. Additionally, we discuss how nematodes modulate the reactive oxygen species (ROS and RNA silencing pathways in addition to post-translational modifications in their own favor for successful parasitism in plants.

  15. In vitro spore germination and gametophytic growth development of ...

    African Journals Online (AJOL)

    The effects of sucrose, pH and plant growth hormones on spore germination percentage and gametophyte growths of Pteris tripartita were studied. Various morphological structures of gametophytes were observed namely, filamentous, spatulate and heart stages in the MS culture medium with hormones. After 15 days, the ...

  16. Sugar signals and the control of plant growth and development

    NARCIS (Netherlands)

    Lastdrager, Jeroen|info:eu-repo/dai/nl/357520076; Hanson, Johannes|info:eu-repo/dai/nl/304822299; Smeekens, Sjef|info:eu-repo/dai/nl/072489995

    2014-01-01

    Sugars have a central regulatory function in steering plant growth. This review focuses on information presented in the past 2 years on key players in sugar-mediated plant growth regulation, with emphasis on trehalose 6-phosphate, target of rapamycin kinase, and Snf1-related kinase 1 regulatory

  17. Postnatal growth, age estimation and development of foraging ...

    Indian Academy of Sciences (India)

    Unknown

    growth after the first year (Kunz and Stern 1995). The values of the lengths of forearm and epiphyseal gap dur- ing their linear phases of growth increased during the preflight period and decreased during the postflight period, and were reliable for deriving equations to esti- mate the age of young bats (e.g. Kunz and Robson ...

  18. Implications of population growth for Nigeria's development | Fan ...

    African Journals Online (AJOL)

    Nigeria's population that was 16 million in 1911 is about 140 million today. Attention invariably turns to the implications of this growth to the qualities of life for her inhabitants. The paper notes that high birth rate, low death rate and migration are the sources of the high population growth in Nigeria. The population then ...

  19. Economics of Sustainable Development. Competitiveness and Economic Growth

    Directory of Open Access Journals (Sweden)

    Dorel AILENEI

    2011-02-01

    Full Text Available Economic growth is one of the most important issues of humanity. Both in national economies and world economy, recession and prosperity periods are regularly succeeding with different amplitudes. But beyond these fluctuations and their effects, the results are important: performance and economic growth. Because of the problematical issue of economic growth, the authors are trying to critically reflect on the economic growth concept and on its implications on the praxis area. Although there is a large literature about economic growth modeling, it is intriguing that there still are some serious obstacles for conceptualization and praxis. Only the simple fact that the economic growth process needs serious thinking on the time dimension is sufficient for understanding the real difficulties of this problematical issue. As for the economic growth praxis, a clear analysis of the interests system within an economy is needed. Without trying to find miraculous solutions for the economic growth issue, the authors suggest a clear and correct analysis of this important subject.

  20. Disease dynamics in a specialized parasite of ant societies.

    Directory of Open Access Journals (Sweden)

    Sandra B Andersen

    Full Text Available Coevolution between ant colonies and their rare specialized parasites are intriguing, because lethal infections of workers may correspond to tolerable chronic diseases of colonies, but the parasite adaptations that allow stable coexistence with ants are virtually unknown. We explore the trade-offs experienced by Ophiocordyceps parasites manipulating ants into dying in nearby graveyards. We used field data from Brazil and Thailand to parameterize and fit a model for the growth rate of graveyards. We show that parasite pressure is much lower than the abundance of ant cadavers suggests and that hyperparasites often castrate Ophiocordyceps. However, once fruiting bodies become sexually mature they appear robust. Such parasite life-history traits are consistent with iteroparity--a reproductive strategy rarely considered in fungi. We discuss how tropical habitats with high biodiversity of hyperparasites and high spore mortality has likely been crucial for the evolution and maintenance of iteroparity in parasites with low dispersal potential.

  1. Noonan syndrome: an update on growth and development.

    Science.gov (United States)

    Yart, Armelle; Edouard, Thomas

    2018-02-01

    To provide an update on recent developments on Noonan syndrome with a special focus on endocrinology, bone, and metabolism aspects. The key issues still to be resolved and the future therapeutic perspectives will be discussed. The discovery of the molecular genetic causes of Noonan syndrome and Noonan-syndrome-related disorders has permitted us to better understand the mechanisms underlying the different symptoms of these diseases and to establish genotype-phenotype correlations (in growth patterns for example). In addition to the classical clinical hallmarks of Noonan syndrome, new important aspects include decreased fertility in men, lean phenotype with increased energy expenditure and possible impact on carbohydrate metabolism/insulin sensitivity, and impaired bone health. Further clinical studies are needed to investigate the long-term impact of these findings and their possible interconnections. Finally, the understanding of the crucial role of RAS/mitogen-activated protein kinases dysregulation in the pathophysiology of Noonan syndrome allows us to devise new therapeutic approaches. Some agents are currently undergoing clinical trials in Noonan syndrome patients. On the last 10 years, our knowledge of the molecular basis and the pathophysiology of Noonan syndrome has greatly advanced allowing us to gain insight in all the aspects of this disease and to devise new specific therapeutic strategies.

  2. The early growth and development study: a prospective adoption design.

    Science.gov (United States)

    Leve, Leslie D; Neiderhiser, Jenae M; Ge, Xiaojia; Scaramella, Laura V; Conger, Rand D; Reid, John B; Shaw, Daniel S; Reiss, David

    2007-02-01

    The Early Growth and Development Study is a prospective adoption study of birth parents, adoptive parents, and adopted children (N=359 triads) that was initiated in 2003. The primary study aims are to examine how family processes mediate or moderate the expression of genetic influences in order to aid in the identification of specific family processes that could serve as malleable targets for intervention. Participants in the study are recruited through adoption agencies located throughout the United States, following the birth of a child. Assessments occur at 6-month intervals until the child reaches 3 years of age. Data collection includes the following primary constructs: infant and toddler temperament, social behavior, and health; birth and adoptive parent personality characteristics, psychopathology, competence, stress, and substance use; adoptive parenting and marital relations; and prenatal exposure to drugs and maternal stress. Preliminary analyses suggest the representativeness of the sample and minimal confounding effects of current trends in adoption practices, including openness and selective placement. Future plans are described.

  3. Parasite transmission in a natural multihost–multiparasite community

    Science.gov (United States)

    2017-01-01

    Understanding the transmission and dynamics of infectious diseases in natural communities requires understanding the extent to which the ecology, evolution and epidemiology of those diseases are shaped by alternative hosts. We performed laboratory experiments to test how parasite spillover affected traits associated with transmission in two co-occurring parasites: the bacterium Pasteuria ramosa and the fungus Metschnikowia bicuspidata. Both parasites were capable of transmission from the reservoir host (Daphnia dentifera) to the spillover host (Ceriodaphnia dubia), but this occurred at a much higher rate for the fungus than the bacterium. We quantified transmission potential by combining information on parasite transmission and growth rate, and used this to compare parasite fitness in the two host species. For both parasites, transmission potential was lower in the spillover host. For the bacterium, virulence was higher in the spillover host. Transmission back to the original host was high for both parasites, with spillover influencing transmission rate of the fungus but not the bacterium. Thus, while inferior, the spillover host is not a dead-end for either parasite. Overall, our results demonstrate that the presence of multiple hosts in a community can have important consequences for disease transmission, and host and parasite fitness. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289264

  4. Parasite transmission in a natural multihost-multiparasite community.

    Science.gov (United States)

    Auld, Stuart K J R; Searle, Catherine L; Duffy, Meghan A

    2017-05-05

    Understanding the transmission and dynamics of infectious diseases in natural communities requires understanding the extent to which the ecology, evolution and epidemiology of those diseases are shaped by alternative hosts. We performed laboratory experiments to test how parasite spillover affected traits associated with transmission in two co-occurring parasites: the bacterium Pasteuria ramosa and the fungus Metschnikowia bicuspidata Both parasites were capable of transmission from the reservoir host ( Daphnia dentifera ) to the spillover host ( Ceriodaphnia dubia ), but this occurred at a much higher rate for the fungus than the bacterium. We quantified transmission potential by combining information on parasite transmission and growth rate, and used this to compare parasite fitness in the two host species. For both parasites, transmission potential was lower in the spillover host. For the bacterium, virulence was higher in the spillover host. Transmission back to the original host was high for both parasites, with spillover influencing transmission rate of the fungus but not the bacterium. Thus, while inferior, the spillover host is not a dead-end for either parasite. Overall, our results demonstrate that the presence of multiple hosts in a community can have important consequences for disease transmission, and host and parasite fitness.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'. © 2017 The Author(s).

  5. Overview on the effects of parasites on fish health

    Science.gov (United States)

    Iwanowicz, D.D.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.

    2011-01-01

    It is believed by many that parasites are only as important as the fish they infect. Parasites are ubiquitous, primarily surviving in a dynamic equilibrium with their host(s) and they are often overlooked in fish health assessments. Changes in the environment, both anthropogenic and environmental, can alter the parasite/host equilibrium and cause disease or mortality in fish. Therefore it is imperative that we have knowledge of both parasites and parasitic communities within a given population. When fish kills occur, it can often be associated with changes in parasite density and community composition. Often the damage associated with these fish is relative to the rate of infestation with the parasite; a fish that is lightly infected will show few signs of the parasite, while a heavily infected fish may become physiologically impaired and even die. Parasites can cause mechanical damage (fusion of gill lamellae, tissue replacement), physiological damage (cell proliferation, immunomodulation, detrimental behavioral responses, altered growth) and reproductive damage. As parasitism is the most common lifestyle on the planet, understanding its role in the environment may help researchers understand changes in a given fish population or stream ecosystem.

  6. Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

    Science.gov (United States)

    Silver, Emily J.; D'Amato, Anthony W.; Fraver, Shawn; Palik, Brian J.; Bradford, John B.

    2013-01-01

    The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types. Moreover, the effectiveness of approaches recommended for restoring old-growth structural conditions to managed forests, such as the application of extended rotation forestry, has been little studied. This study uses several long-term datasets from old growth, extended rotation, and unmanaged second growth Pinus resinosa (red pine) forests in northern Minnesota, USA, to quantify the range of variation in structural conditions for this forest type and to evaluate the effectiveness of extended rotation forestry at promoting the development of late-successional structural conditions. Long-term tree population data from permanent plots for one of the old-growth stands and the extended rotation stands (87 and 61 years, respectively) also allowed for an examination of the long-term structural dynamics of these systems. Old-growth forests were more structurally complex than unmanaged second-growth and extended rotation red pine stands, due in large part to the significantly higher volumes of coarse woody debris (70.7 vs. 11.5 and 4.7 m3/ha, respectively) and higher snag basal area (6.9 vs. 2.9 and 0.5 m2/ha, respectively). In addition, old-growth forests, although red pine-dominated, contained a greater abundance of other species, including Pinus strobus, Abies balsamea, and Picea glauca relative to the other stand types examined. These differences between stand types largely reflect historic gap-scale disturbances within the old-growth systems and their corresponding structural and compositional legacies. Nonetheless, extended rotation thinning treatments, by accelerating advancement to larger tree diameter

  7. Parasitism, productivity, and population growth: response of Least Bell's Vireos (Vireo bellii pusillus) and Southwestern Willow Flycatchers (Empidonax traillii extimus) to cowbird (Molothrus spp.) control

    Science.gov (United States)

    Kus, Barbara E.; Whitfield, Mary J.

    2005-01-01

    Cowbird (Molothrus spp.) control is a major focus of recovery-oriented management of two endangered riparian bird species,the Least Bell's Vireo (Vireo bellii pusillus) and Southwestern Willow Flycatcher (Empidonax traillii extimus). During the past 20 years, annual trapping of cowbirds at Least Bell's Vireo and Southwestern Willow Flycatcher breeding sites has eliminated or reduced parasitism in comparison with pretrapping rates and, thereby, significantly increased seasonal productivity of nesting pairs. Enhanced productivity, in turn, has resulted in an 8-fold increase in numbers of Least Bell's Vireos; Southwestern Willow Flycatcher abundance, however, has changed little, and at some sites has declined despite cowbird control. Although generally successful by these short-term measures of host population response, cowbird control poses potential negative consequences for long-term recovery of endangered species. As currently employed, cowbird control lacks predetermined biological criteria to trigger an end to the control, making these species' dependence on human intervention open-ended. Prolonged reliance on cowbird control to manage endangered species can shift attention from identifying and managing other factors that limit populations--in particular, habitat availability. On the basis of our analysis of these long-term programs, we suggest that cowbird control be reserved for short-term crisis management and be replaced, when appropriate, by practices emphasizing restoration and maintenance of natural processes on which species depend. /// El manejo orientado hacia la recuperación de dos especies de aves ribereñas Vireo belli pusillus y Empidonax trailli extimus se ha focalizado principalmente en el control de los Molothrus spp parásitos. Durante los pasados 20 años, la captura anual de los Molothrus en las áreas de nidificación de Vireo belli pusillus y Empidonax trailli extimus ha eliminado o reducido el parasitismo en comparación con las tasas

  8. Mechanisms of cellular invasion by intracellular parasites.

    Science.gov (United States)

    Walker, Dawn M; Oghumu, Steve; Gupta, Gaurav; McGwire, Bradford S; Drew, Mark E; Satoskar, Abhay R

    2014-04-01

    Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.

  9. Parasitism, personality and cognition in fish.

    Science.gov (United States)

    Barber, I; Mora, A B; Payne, E M; Weinersmith, K L; Sih, A

    2017-08-01

    It is well established that parasites can have profound effects on the behaviour of host organisms, and that individual differences in behaviour can influence susceptibility to parasite infections. Recently, two major themes of research have developed. First, there has been a growing interest in the proximate, mechanistic processes underpinning parasite-associated behaviour change, and the interactive roles of the neuro-, immune, and other physiological systems in determining relationships between behaviour and infection susceptibility. Secondly, as the study of behaviour has shifted away from one-off measurements of single behaviours and towards a behavioural syndromes/personality framework, research is starting to focus on the consequences of parasite infection for temporal and contextual consistency of behaviour, and on the implications of different personality types for infection susceptibility. In addition, there is increasing interest in the potential for relationships between cognition and personality to also have implications for host-parasite interactions. As models well-suited to both the laboratory study of behaviour and experimental parasitology, teleost fish have been used as hosts in many of these studies. In this review we provide a broad overview of the range of mechanisms that potentially generate links between fish behaviour, personality, and parasitism, and illustrate these using examples drawn from the recent literature. In addition, we examine the potential interactions between cognition, personality and parasitism, and identify questions that may be usefully investigated with fish models. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. New Record of Rhinopoma microphyllum with the Invested Parasites and Microbes in the Developed Ecotourism Area of South Lombok Island NTB

    Science.gov (United States)

    Fajri, S. R.; NPrimawati, S.; Hadi, I.; Tresnani, G.

    2018-01-01

    Rhinopoma microphyllum is a bat species that lives in a habitat covered by grove of trees and shrubs in the primary forest vegetation. These species is included in the IUCN Red List list with Least Concern (LC) status or at the least information. This study was to describe of R. microphyllum as a new record in the southern of Lombok, and to examine the parasites and microbes that infest it. The study was carried out in the developed ecotourism area of southern Lombok Island of NTB during February-April 2017. A modified net and quadrant for cave ceiling was used to collect bat sample. Ectoparasite collection was done by combing the bat’s hair and the falling specimens were collected. The endoparasite examination was done by the flotation methods of intestinal contents, while microbial examination was done by collecting the microbes from oral cavity and feces. The results showed the discovery of R. microphyllum in two ecotourism development sites, The Buwun Cave and The Gale Gale Bangkang Cave Prabu Village, Central Lombok. The endoparasit examination found 4 species of endoparasit, 1 species of Coccidia sp, 2 species of Trematodes from Lecithodendridae Family (Prosthodendrium sp and Acanthatrium sp) and 1 unidentified Nematode specimen. The ectoparasite examination found only 1 species, Ischnopsyllus hexactenus (The long Eared Bat Flea), and the microbes found from oral cavity analysis are the Gram positive Coccus (Stphylococcus aureus) and faecal analysis are the Coccobacil Gram negative (Providensia penneri).

  11. A REVIEW OF FINANCE–GROWTH NEXUS THEORIES: HOW DOES DEVELOPMENT FINANCE FITS IN?

    OpenAIRE

    MARWA Nyankomo; ZHANJE Stephen

    2015-01-01

    The finance growth-nexus debates have been contentious over the past three decades both empirically and theoretically. To contribute to this debate, the current paper presents a concise review of finance-growths nexus theoretical development and the current debate around growth-finance nexus theories. Then, it extends the current theoretical debate to include development finance within the broader scheme of finance-growth discourse. The key emerging trend is that, most of the contemporary the...

  12. Low transformation growth factor-β1 production and collagen synthesis correlate with the lack of hepatic periportal fibrosis development in undernourished mice infected with Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Andreia Ferreira Barros

    2014-04-01

    Full Text Available Undernourished mice infected (UI submitted to low and long-lasting infections by Schistosoma mansoni are unable to develop the hepatic periportal fibrosis that is equivalent to Symmers’ fibrosis in humans. In this report, the effects of the host’s nutritional status on parasite (worm load, egg viability and maturation and host (growth curves, biology, collagen synthesis and characteristics of the immunological response were studied and these are considered as interdependent factors influencing the amount and distribution of fibrous tissue in hepatic periovular granulomas and portal spaces. The nutritional status of the host influenced the low body weight and low parasite burden detected in UI mice as well as the number, viability and maturation of released eggs. The reduced oviposition and increased number of degenerated or dead eggs were associated with low protein synthesis detected in deficient hosts, which likely induced the observed decrease in transformation growth factor (TGF-β1 and liver collagen. Despite the reduced number of mature eggs in UI mice, the activation of TGF-β1 and hepatic stellate cells occurred regardless of the unviability of most miracidia, due to stimulation by fibrogenic proteins and eggshell glycoproteins. However, changes in the repair mechanisms influenced by the nutritional status in deficient animals may account for the decreased liver collagen detected in the present study.

  13. Development and Evaluation of Herbal Formulations for Hair Growth

    Directory of Open Access Journals (Sweden)

    Lipi Purwal

    2008-01-01

    Full Text Available Hair formulation of Emblica officinalis (Euphorbiaceae, Bacopa, monnieri (Scrophulariaceae, Trigonella foenumgraecum (Leguminosae, Murraya koenigii (Rutaceae in various concentrations in the form of herbal oil were studied for their hair growth activity. Each drug was tested for their hair growth activity in a concentration range for 1-10% separately. Based on these results mixture of crude drugs Murraya koeniigi, leaf (Rutaceae, Bacopa monnieri, leaf (Scrophulariaceae, Trigonella foenumgraecum (Leguminosae, Murraya koenigii (Rutaceae were prepared in varying concentration in the form of herbal hair oil by three different oils preparation techniques and were tested for hair growth activity. The result revealed that the hair growth activity of each drug was found proportional to the concentration range tested. Similarly higher concentrations of drug in the formulation were found to have higher hair growth activities. But looking towards the formulation viscosity the maximum concentration of combined drug was found to be 30% at their maximum level. The formulation containing 7.5% of each drug used for the study and showed excellent hair growth activity with standard (2% minoxidil ethanolic solution by an enlargement of follicular size and prolongation of the anagen phase. It holds the promise of potent herbal alternative for minoxidil. Excellent results of hair growth were seen in formulation prepared by cloth pouch decoction method of oils preparation technique.

  14. Regulation of Gene Expression in Protozoa Parasites

    Directory of Open Access Journals (Sweden)

    Consuelo Gomez

    2010-01-01

    Full Text Available Infections with protozoa parasites are associated with high burdens of morbidity and mortality across the developing world. Despite extensive efforts to control the transmission of these parasites, the spread of populations resistant to drugs and the lack of effective vaccines against them contribute to their persistence as major public health problems. Parasites should perform a strict control on the expression of genes involved in their pathogenicity, differentiation, immune evasion, or drug resistance, and the comprehension of the mechanisms implicated in that control could help to develop novel therapeutic strategies. However, until now these mechanisms are poorly understood in protozoa. Recent investigations into gene expression in protozoa parasites suggest that they possess many of the canonical machineries employed by higher eukaryotes for the control of gene expression at transcriptional, posttranscriptional, and epigenetic levels, but they also contain exclusive mechanisms. Here, we review the current understanding about the regulation of gene expression in Plasmodium sp., Trypanosomatids, Entamoeba histolytica and Trichomonas vaginalis.

  15. Regulation of gene expression in protozoa parasites.

    Science.gov (United States)

    Gomez, Consuelo; Esther Ramirez, M; Calixto-Galvez, Mercedes; Medel, Olivia; Rodríguez, Mario A

    2010-01-01

    Infections with protozoa parasites are associated with high burdens of morbidity and mortality across the developing world. Despite extensive efforts to control the transmission of these parasites, the spread of populations resistant to drugs and the lack of effective vaccines against them contribute to their persistence as major public health problems. Parasites should perform a strict control on the expression of genes involved in their pathogenicity, differentiation, immune evasion, or drug resistance, and the comprehension of the mechanisms implicated in that control could help to develop novel therapeutic strategies. However, until now these mechanisms are poorly understood in protozoa. Recent investigations into gene expression in protozoa parasites suggest that they possess many of the canonical machineries employed by higher eukaryotes for the control of gene expression at transcriptional, posttranscriptional, and epigenetic levels, but they also contain exclusive mechanisms. Here, we review the current understanding about the regulation of gene expression in Plasmodium sp., Trypanosomatids, Entamoeba histolytica and Trichomonas vaginalis.

  16. Growth and development of male "little" mice assessed with Parks' theory of feeding and growth.

    Science.gov (United States)

    Puche, Rodolfo C; Alloatti, Rosa; Chapo, Gustavo

    2002-01-01

    This work was designed to characterize the appetite kinetics and growth of male C57BL/6J (lit) mice. Those variables were assessed with Parks' function of ad libitum feeding and growth. Heterozygous mice (lit/+) attained their mature weight at 12-15 weeks of age, peak growth rate (3.5 g/week) at 5 weeks and displayed the normal decay of food conversion efficiency as a function of age. The homozygous genotype has a chronic defect in the synthesis and secretion of growth hormone (GH). Homozygous mice could not be assessed with Park's function. From the 4th to the 15th week of age, body weight increased linearly and exhibited constant food conversion efficiency. Food intake of both genotypes was commensurate with their body weights. Lit/lit mice became progressively obese. At 40 weeks of age, body fat of lit/lit mice was fivefold that of lit/+ and their body weight was similar to their heterozygous controls. The chronic deficiency of growth hormone produced a lower bone mass (compared to heterozygous controls). Bone mass of both genotypes attained maturity at 12-15 weeks with a maximum growth rate at 5 weeks. Body weight and bone mass grow harmoniously in lit/+ but not in lit/lit mice.

  17. Children and Parasitic Diseases

    Science.gov (United States)

    ... because they disproportionately affect impoverished people. More on: Neglected Tropical Diseases Prevention One of the most important ways to help prevent these parasitic diseases is to teach children the importance of washing hands correctly with soap ...

  18. Parasites and the skin

    African Journals Online (AJOL)

    2009-06-11

    Jun 11, 2009 ... those conditions that are encountered in daily practice and to remind you of those ... care conditions. Parasitic infections can be solely confined to the skin, as seen ..... endemic areas or may become chronic and disseminate.

  19. Parasitic Diseases: Glossary

    Science.gov (United States)

    ... of the leg. Endemic: A disease that is native to a particular geographic region. Epidemiology: The study ... parasites/glossary.html) T Telediagnosis: The transmission of digital images captured from a clinical specimen and sent ...

  20. How second-growth northern hardwoods develop after thinning

    Science.gov (United States)

    Robert W., Jr. Wilson

    1953-01-01

    In the northern hardwood region, second-growth stands occupy thousands of acres. These stands are of all ages, in all conditions. They were brought about by fire, charcoal and fuelwood cuttings, land abandonment, or a combination of these causes.

  1. Redefining prosperity : resource productivity, economic growth and sustainable development

    OpenAIRE

    Sustainable Development Commission

    2003-01-01

    This report seeks to stimulate debate on how we define prosperity and addresses the inadequacies of standard definitions of Gross Domestic Product and economic growth as yardsticks for well-being. Publisher PDF

  2. Immunogene and viral transcript dynamics during parasitic Varroa destructor mite infection of developing honey bee (Apis mellifera) pupae.

    Science.gov (United States)

    Kuster, Ryan D; Boncristiani, Humberto F; Rueppell, Olav

    2014-05-15

    The ectoparasitic Varroa destructor mite is a major contributor to the ongoing honey bee health crisis. Varroa interacts with honey bee viruses, exacerbating their pathogenicity. In addition to vectoring viruses, immunosuppression of the developing honey bee hosts by Varroa has been proposed to explain the synergy between viruses and mites. However, the evidence for honey bee immune suppression by V. destructor is contentious. We systematically studied the quantitative effects of experimentally introduced V. destructor mites on immune gene expression at five specific time points during the development of the honey bee hosts. Mites reproduced normally and were associated with increased titers of deformed wing virus in the developing bees. Our data on different immune genes show little evidence for immunosuppression of honey bees by V. destructor. Experimental wounding of developing bees increases relative immune gene expression and deformed wing virus titers. Combined, these results suggest that mite feeding activity itself and not immunosuppression may contribute to the synergy between viruses and mites. However, our results also suggest that increased expression of honey bee immune genes decreases mite reproductive success, which may be explored to enhance mite control strategies. Finally, our expression data for multiple immune genes across developmental time and different experimental treatments indicates co-regulation of several of these genes and thus improves our understanding of the understudied honey bee immune system. © 2014. Published by The Company of Biologists Ltd.

  3. House and stable fly (Diptera: Muscidae) seasonal abundance, larval development substrates, and natural parasitism on small equine farms in Florida

    Science.gov (United States)

    This 1-year study was designed to determine adult fly population levels and development substrates on four small equine farms. Results showed that pest flies were present year-round, but differences existed in population levels among farms and seasons. Fly larvae were not found on two of the farms, ...

  4. Productivity Growth and the Regional Dynamics of Antebellum Southern Development

    OpenAIRE

    Alan L. Olmstead; Paul W. Rhode

    2010-01-01

    Between 1800 and 1860, the United States became the preeminent world supplier of cotton as output increased sixty-fold. Technological changes, including the introduction of improved cotton varieties, contributed significantly to this growth. Measured output per worker in the cotton sector rose four-fold and large regional differences emerged. By 1840, output per worker in the New South was twice that in the Old South. The economy-wide increase is explained, in equal measure, by growth in outp...

  5. Imaging of parasitic diseases

    International Nuclear Information System (INIS)

    Haddad, Maurice C.

    2008-01-01

    This book provides an overview of the imaging findings of parasitic diseases using modern imaging equipment. The chapters consist of short descriptions of causative pathogens, epidemiology, modes of transmission, pathology, clinical manifestations, laboratory tests, and imaging findings, with illustrative examples of parasitic diseases that can affect various systems of the human body. Tables summarizing key diagnostic features and clinical data pertinent to diagnosis are also included. This book is intended for radiologists worldwide. (orig.)

  6. Imaging of parasitic diseases

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, Maurice C. [American Univ. of Beirut Medical Center (Lebanon). Dept. of Diagnostic Radiology; Abd El Bagi, Mohamed E. [Riyadh Military Hospital (Saudi Arabia). Radiology and Imaging Dept. 920W; Tamraz, Jean C. (eds.) [CHU Hotel-Dieu de France, Beirut (Lebanon)

    2008-07-01

    This book provides an overview of the imaging findings of parasitic diseases using modern imaging equipment. The chapters consist of short descriptions of causative pathogens, epidemiology, modes of transmission, pathology, clinical manifestations, laboratory tests, and imaging findings, with illustrative examples of parasitic diseases that can affect various systems of the human body. Tables summarizing key diagnostic features and clinical data pertinent to diagnosis are also included. This book is intended for radiologists worldwide. (orig.)

  7. Pathoecology of Chiribaya parasitism

    Directory of Open Access Journals (Sweden)

    Martinson Elizabeth

    2003-01-01

    Full Text Available The excavations of Chiribaya culture sites in the Osmore drainage of southern Peru focused on the recovery of information about prehistoric disease, including parasitism. The archaeologists excavated human, dog, guinea pig, and llama mummies. These mummies were analyzed for internal and external parasites. The results of the analysis and reconstruction of prehistoric life from the excavations allows us to interpret the pathoecology of the Chiribaya culture.

  8. Developing countries are combating climate change. Actions in developing countries that slow growth in carbon emissions

    International Nuclear Information System (INIS)

    Reid, Walter V.; Goldemberg, Jose

    1998-01-01

    The role of developing countries in helping to solve the problem of climate change is increasingly a focus of political controversy. With levels of greenhouse gas emissions projected to exceed those of developed countries by 2020, some industrialized countries are calling on developing countries to take stronger action to meet the commitments they have made in the Framework Convention on Climate Change (FCCC). This review of recent policy changes in developing countries, however, suggests that they are already taking little appreciated steps that reduce rates of growth in carbon emissions. Indeed, since the 1992 signing of the FCCC, carbon emission savings in developing countries may be greater than those attained by industrialized countries. A major source of these gains can be attributed to energy price reforms that are likely to have led to substantial gains in production and end-use efficiency. (author)

  9. Prevalence of Parasitic Contamination

    Science.gov (United States)

    Ismail, Yazan

    2016-01-01

    One of the main ways in transmitting parasites to humans is through consuming contaminated raw vegetables. The aim of this study was to evaluate the prevalence of parasitological contamination (helminthes eggs, Giardia and Entamoeba histolytica cysts) of salad vegetables sold at supermarkets and street vendors in Amman and Baqa’a – Jordan. A total of 133 samples of salad vegetables were collected and examined for the prevalence of parasites. It was found that 29% of the samples were contaminated with different parasites. Of the 30 lettuce, 33 tomato, 42 parsley and 28 cucumber samples examined the prevalence of Ascaris spp. eggs was 43%, 15%, 21% and 4%; Toxocara spp. eggs was 30%, 0%, 0% and 4%; Giardia spp. cysts was 23%, 6%, 0% and 0%; Taenia/Echinococcus eggs was 20%, 0%, 5% and 0%; Fasciola hepatica eggs was 13%, 3%, 2% and 0%; and E. histolytica cysts was 10%, 6%, 0% and 0%, respectively. There was no significant difference in the prevalence of parasite in salad vegetables either between supermarkets and street vendors, or between Amman and Baqa’a, Ascaris spp. was found to be the highest prevalent parasite in salad vegetables from supermarkets and street vendors and from Amman and Baqa’a. Our results pointed out that, the parasitic contamination of salad vegetables found in our study might be caused by irrigating crops with faecal contaminated water. We concluded that salad vegetables sold in Amman and Baqa’a may cause a health risk to consumers.

  10. Molecular genetic transfection of the coccidian parasite Sarcocystis neurona.

    Science.gov (United States)

    Gaji, Rajshekhar Y; Zhang, Deqing; Breathnach, Cormac C; Vaishnava, Shipra; Striepen, Boris; Howe, Daniel K

    2006-11-01

    Sarcocystis neurona is an apicomplexan parasite that is the major cause of equine protozoal myeloencephalitis (EPM). The biology of this pathogen remains poorly understood in part due to unavailability of molecular genetic tools. Hence, with an objective to develop DNA transfection capabilities for S. neurona, the 5' flanking region of the SnSAG1 gene was isolated from a genomic library and used to construct expression plasmids. In transient assays, the reporter molecules beta-galactosidase (beta-gal) and yellow fluorescent protein (YFP) could be detected in electroporated S. neurona, thereby confirming the feasibility of transgene expression in this organism. Stable transformation of S. neurona was achieved using a mutant dihydrofolate reductase thymidylate synthase (DHFR-TS) gene of Toxoplasma gondii that confers resistance to pyrimethamine. This selection system was used to create transgenic S. neurona that stably express beta-gal and YFP. As shown in this study, these transgenic clones can be useful for analyzing growth rate of parasites in vitro and for assessing drug sensitivities. More importantly, the DNA transfection methods described herein should greatly facilitate studies examining intracellular parasitism by this important coccidian pathogen.

  11. Parasites in marine food webs

    Science.gov (United States)

    Lafferty, Kevin D.

    2013-01-01

    Most species interactions probably involve parasites. This review considers the extent to which marine ecologists should consider parasites to fully understand marine communities. Parasites are influential parts of food webs in estuaries, temperate reefs, and coral reefs, but their ecological importance is seldom recognized. Though difficult to observe, parasites can have substantial biomass, and they can be just as common as free-living consumers after controlling for body mass and trophic level. Parasites have direct impacts on the energetics of their hosts and some affect host behaviors, with ecosystem-level consequences. Although they cause disease, parasites are sensitive components of ecosystems. In particular, they suffer secondary extinctions due to biodiversity loss. Some parasites can also return to a system after habitat restoration. For these reasons, parasites can make good indicators of ecosystem integrity. Fishing can indirectly increase or decrease parasite populations and the effects of climate change on parasites are likely to be equally as complex.

  12. Beyond the reproductive effect of sex steroids: their role during immunity to helminth parasite infections.

    Science.gov (United States)

    Hernández-Bello, R; Nava-Castro, K; Muñiz-Hernández, S; Nava-Luna, P; Trejo-Sánchez, Itztli; Tiempos-Guzmán, N; Mendoza-Rodríguez, Y; Morales-Montor, J

    2012-10-01

    During the helminth infections, the immune system tends to be modulated by host's sex hormones. Actually, many studies show the reciprocal relationship between sex steroids, the immune system and the elimination or establishment of helminth parasites. Is well known that innate immune response determines the type of adaptive immune response, so the effects in the innate immune response by hormones may affect subsequent adaptive immunity. The sex steroids as estrogens, progesterone and testosterone regulate growth, differentiation, survival and function of many cell types that could be involved in process like homeostasis and immunity, but also have a direct effect on the helminthes, that may probably be mediated by specific receptors on these parasites. Sex steroids, parasites and immunity are closely connected, and their interconnection is involved in the maintenance of elimination or establishment of helminthes in an immunocompetent host. For that reason, understanding the action's mechanisms of sex steroids on immune cells and its direct effect on helminth parasites is important for further progress in the development of novel therapies for chronic helminth diseases associated to immune dysregulation. In this review, we will describe the effects of sex steroids on the immune response during helminth infections as well as the direct effect in these parasites, and the possible implications of these effects on the incidence of several helminth infections.

  13. Polyamine uptake by the intraerythrocytic malaria parasite, Plasmodium falciparum.

    Science.gov (United States)

    Niemand, J; Louw, A I; Birkholtz, L; Kirk, K

    2012-09-01

    Polyamines and the enzymes involved in their biosynthesis are present at high levels in rapidly proliferating cells, including cancer cells and protozoan parasites. Inhibition of polyamine biosynthesis in asexual blood-stage malaria parasites causes cytostatic arrest of parasite development under in vitro conditions, but does not cure infections in vivo. This may be due to replenishment of the parasite's intracellular polyamine pool via salvage of exogenous polyamines from the host. However, the mechanism(s) of polyamine uptake by the intraerythrocytic parasite are not well understood. In this study, the uptake of the polyamines, putrescine and spermidine, into Plasmodium falciparum parasites functionally isolated from their host erythrocyte was investigated using radioisotope flux techniques. Both putrescine and spermidine were taken up into isolated parasites via a temperature-dependent process that showed cross-competition between different polyamines. There was also some inhibition of polyamine uptake by basic amino acids. Inhibition of polyamine biosynthesis led to an increase in the total amount of putrescine and spermidine taken up from the extracellular medium. The uptake of putrescine and spermidine by isolated parasites was independent of extracellular Na(+) but increased with increasing external pH. Uptake also showed a marked dependence on the parasite's membrane potential, decreasing with membrane depolarization and increasing with membrane hyperpolarization. The data are consistent with polyamines being taken up into the parasite via an electrogenic uptake process, energised by the parasite's inwardly negative membrane potential. Copyright © 2012 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  14. Influence of growth retardant on growth and development of Euphorbia pulcherrima Willd. ex Klotzsch

    Directory of Open Access Journals (Sweden)

    Anna Pobudkiewicz

    2014-09-01

    Full Text Available This study was undertaken to evaluate the influence of single foliar flurprimidol treatment on morphology and transpiration of ‘Roman’ and ‘Freedom Red’ poinsettias. The growth retardant flurprimidol (Topflor 015 SL was applied once as a foliar spray at concentrations of 5, 10 or 15 mg × dm-3 when lateral shoots were about 5 cm in length. Single foliar flurprimidol treatment was sufficient to inhibit stem elongation of both poinsettia cultivars. The degree of growth inhibition depended on cultivar and growth retardant concentration. As compared to the control, the shoots of flurprimidol treated ‘Roman’ and ‘Freedom Red’ plants were up to 44% and 37% shorter, respectively. The desirable plant heights for ‘Roman’ and ‘Freedom Red’ poinsettias were obtained with flurprimidol at concentrations of 5 and 10 mg × dm-3, respectively. The shoots of flurprimidol sprayed poinsettia were also more rigid and aligned relative to each other and thus the bracts on the plant were placed on the same level. The diameters of growth retardant treated poinsettias were up to 13% narrower. The leaf areas, petiole lengths, fresh and dry weights of ‘Roman’ and ‘Freedom Red’ poinsettias treated with flurprimidol were substantially smaller as compared to the control. The bract diameters of both poinsettia cultivars were only slightly affected by growth retardant application. Plants exposed to flurprimidol had also intensified green leaf pigmentation. There was almost no abscission of the oldest leaves in the low portions of growth retardant treated plants, compared to those of the control ones. Flurprimidol had no effect on transpiration rate per unit leaf area and stomatal conductance in both poinsettia cultivars. No phytotoxicity was observed in flurprimidol treated plants. Chemical name used: α-(1-methylethyl-α-[4-(trifluromethoxyphenyl]-5-pyrimidinemethanol (flurprimidol.

  15. Growth Hormone Research Society perspective on the development of long-acting growth hormone preparations

    DEFF Research Database (Denmark)

    Christiansen, Jens Sandahl; Backeljauw, Philippe F; Bidlingmaier, Martin

    2016-01-01

    OBJECTIVE: The Growth Hormone (GH) Research Society (GRS) convened a workshop to address important issues regarding trial design, efficacy, and safety of long-acting growth hormone preparations (LAGH). PARTICIPANTS: A closed meeting of 55 international scientists with expertise in GH, including...... and revised in an open forum on the concluding day. This was edited further and then circulated to attendees from academic institutions for review after the meeting. Participants from pharmaceutical companies did not participate in the planning, writing, or in the discussions and text revision on the final...

  16. Parasitic myoma after supracervical laparoscopic histerectomy

    Directory of Open Access Journals (Sweden)

    Maurício Paulo Angelo Mieli

    2013-06-01

    Full Text Available Parasitic myoma is a condition defined as a myoma of extrauterine nourishing. It may occur spontaneously or as a consequence of surgical iatrogeny, after myomectomy or videolaparoscopic supracervical hysterectomy, due to remaining residues of uterine tissue fragments in the pelvic cavity after morcellation. The authors describe two cases in which the patients were submitted to videolaparoscopic supracervical hysterectomy and uterine body removal through morcellation. The sites of development of the parasitic myomas were next to the cervix stump in Case 1, and next to the right round ligament in Case 2. These parasitic myomas were removed by videolaparoscopy. After myomectomies or videolaparoscopic supracervical hysterectomies followed by uterine fragments removal from the pelvic cavity through morcellation, meticulous searching for residues or fragments of uterine tissue is mandatory to prevent the occurrence of parasitic myomas.

  17. Oxygen-sensitive regulation and neuroprotective effects of growth hormone-dependent growth factors during early postnatal development.

    Science.gov (United States)

    Jung, Susan; Boie, Gudrun; Doerr, Helmuth-Guenther; Trollmann, Regina

    2017-04-01

    Perinatal hypoxia severely disrupts metabolic and somatotrophic development, as well as cerebral maturational programs. Hypoxia-inducible transcription factors (HIFs) represent the most important endogenous adaptive mechanisms to hypoxia, activating a broad spectrum of growth factors that contribute to cell survival and energy homeostasis. To analyze effects of systemic hypoxia and growth hormone (GH) therapy (rhGH) on HIF-dependent growth factors during early postnatal development, we compared protein (using ELISA) and mRNA (using quantitative RT PCR) levels of growth factors in plasma and brain between normoxic and hypoxic mice (8% O 2 , 6 h; postnatal day 7 , P7) at P14. Exposure to hypoxia led to reduced body weight ( P controls and was associated with significantly reduced plasma levels of mouse GH ( P controls. In addition, rhGH treatment increased cerebral IGF-1, IGF-2, IGFBP-2, and erythropoietin mRNA levels, resulting in significantly reduced apoptotic cell death in the hypoxic, developing mouse brain. These data indicate that rhGH may functionally restore hypoxia-induced systemic dysregulation of the GH/IGF-1 axis and induce upregulation of neuroprotective, HIF-dependent growth factors in the hypoxic developing brain. Copyright © 2017 the American Physiological Society.

  18. Neuropsychological development in preschool children born with asymmetrical intrauterine growth restriction and impact of postnatal head growth.

    Science.gov (United States)

    Klaric, Andrea Simić; Galić, Slavka; Kolundzić, Zdravko; Bosnjak, Vlatka Mejaski

    2013-07-01

    Neuropsychological development and the impact of postnatal head growth were studied in preschool children with asymmetrical intrauterine growth restriction. Examinees born at term with a birth weight below the 10th percentile were matched to the control group according to chronological and gestational age, gender, and maternal education. Fifty children were in each group, with a mean age of 6 years, 4 months. The Touwen neurological examination, the Čuturić developmental test, an imitative hand positions test, and a visual attention test were performed. There were significant differences (Pmotor variables, the developmental quotient, and the imitative hand positions test. Fine motor skills had the most discriminative power. Relative growth of the head in relation to weight gain was positively correlated to neurocognitive outcome. Intrauterine growth-restricted children with a current head circumference ≤10th percentile had poorer outcomes. Conclusively, intrauterine growth restriction has a negative impact on neurocognitive development. Slow postnatal head growth is correlated with a poorer neuropsychological outcome.

  19. Deiodinase knockdown during early zebrafish development affects growth, development, energy metabolism, motility and phototransduction.

    Directory of Open Access Journals (Sweden)

    Enise Bagci

    Full Text Available Thyroid hormone (TH balance is essential for vertebrate development. Deiodinase type 1 (D1 and type 2 (D2 increase and deiodinase type 3 (D3 decreases local intracellular levels of T3, the most important active TH. The role of deiodinase-mediated TH effects in early vertebrate development is only partially understood. Therefore, we investigated the role of deiodinases during early development of zebrafish until 96 hours post fertilization at the level of the transcriptome (microarray, biochemistry, morphology and physiology using morpholino (MO knockdown. Knockdown of D1+D2 (D1D2MO and knockdown of D3 (D3MO both resulted in transcriptional regulation of energy metabolism and (muscle development in abdomen and tail, together with reduced growth, impaired swim bladder inflation, reduced protein content and reduced motility. The reduced growth and impaired swim bladder inflation in D1D2MO could be due to lower levels of T3 which is known to drive growth and development. The pronounced upregulation of a large number of transcripts coding for key proteins in ATP-producing pathways in D1D2MO could reflect a compensatory response to a decreased metabolic rate, also typically linked to hypothyroidism. Compared to D1D2MO, the effects were more pronounced or more frequent in D3MO, in which hyperthyroidism is expected. More specifically, increased heart rate, delayed hatching and increased carbohydrate content were observed only in D3MO. An increase of the metabolic rate, a decrease of the metabolic efficiency and a stimulation of gluconeogenesis using amino acids as substrates may have been involved in the observed reduced protein content, growth and motility in D3MO larvae. Furthermore, expression of transcripts involved in purine metabolism coupled to vision was decreased in both knockdown conditions, suggesting that both may impair vision. This study provides new insights, not only into the role of deiodinases, but also into the importance of a correct

  20. Financial Development, Econmic Growth and R&D Cyclical Movement

    OpenAIRE

    Fung, Ka Wai Terence; Lau, Chi Keung Marco

    2013-01-01

    This paper builds up an endogenous growth model à la Aghion and Howitt (1992) and Boucekkine et al (2005). We assume that R&D firms use only investment good as input, instead of final good as hypothesized in the above two models. We show that investment price will be a negative function of aggregate quality index; and thus decline over time. In this model, subsidy on R&D has growth-enhancing effect. Moreover, this model predicts unambiguously that R&D is procyclical.

  1. Life History theory hypotheses on child growth: Potential implications for short and long-term child growth, development and health.

    Science.gov (United States)

    Said-Mohamed, Rihlat; Pettifor, John M; Norris, Shane A

    2018-01-01

    Life history theory integrates ecological, physiological, and molecular layers within an evolutionary framework to understand organisms' strategies to optimize survival and reproduction. Two life history hypotheses and their implications for child growth, development, and health (illustrated in the South African context) are reviewed here. One hypothesis suggests that there is an energy trade-off between linear growth and brain growth. Undernutrition in infancy and childhood may trigger adaptive physiological mechanisms prioritizing the brain at the expense of body growth. Another hypothesis is that the period from conception to infancy is a critical window of developmental plasticity of linear growth, the duration of which may vary between and within populations. The transition from infancy to childhood may mark the end of a critical window of opportunity for improving child growth. Both hypotheses emphasize the developmental plasticity of linear growth and the potential determinants of growth variability (including the role of parent-offspring conflict in maternal resources allocation). Implications of these hypotheses in populations with high burdens of undernutrition and infections are discussed. In South Africa, HIV/AIDS during pregnancy (associated with adverse birth outcomes, short duration of breastfeeding, and social consequences) may lead to a shortened window of developmental plasticity of growth. Furthermore, undernutrition and infectious diseases in children living in South Africa, a country undergoing a rapid nutrition transition, may have adverse consequences on individuals' cognitive abilities and risks of cardio-metabolic diseases. Studies are needed to identify physiological mechanisms underlying energy allocation between biological functions and their potential impacts on health. © 2017 Wiley Periodicals, Inc.

  2. Development and validation of SUCROS-Cotton : A potential crop growth simulation model for cotton

    NARCIS (Netherlands)

    Zhang, L.; Werf, van der W.; Cao, W.; Li, B.; Pan, X.; Spiertz, J.H.J.

    2008-01-01

    A model for the development, growth and potential production of cotton (SUCROS-Cotton) was developed. Particular attention was given to the phenological development of the plant and the plasticity of fruit growth in response to temperature, radiation, daylength, variety traits, and management. The

  3. International Trade and Productivity Growth: Exploring the Sectoral Effects for Developing Countries

    OpenAIRE

    Ehsan U. Choudhri; Dalia S. Hakura

    2000-01-01

    The paper estimates an empirical relation based on Krugman's "technological gap" model to explore the influence of the pattern of international trade and production on the overall productivity growth of a developing country. A key result is that increased import competition in medium-growth (but not in low- or high-growth) manufacturing sectors enhances overall productivity growth. The authors also find that a production-share weighted average of (technological leaders') sectoral productivity...

  4. Infection of Gymnodinium sanguineum by the dinoflagellate Amoebophrya sp.: effect of nutrient environment on parasite generation time, reproduction, and infectivity.

    Science.gov (United States)

    Yih, W; Coats, D W

    2000-01-01

    Preliminary attempts to culture Amoebophrya sp., a parasite of Gymnodinium sanguineum from Chesapeake Bay, indicated that success may be influenced by water quality. To explore that possibility, we determined development time, reproductive output, and infectivity of progeny (i.e. dinospores) for Amoebophyra sp. maintained on G. sanguineum grown in four different culture media. The duration of the parasite's intracellular growth phase showed no significant difference among treatments; however, the time required for completion of multiple parasite generations did, with elapsed time to the middle of the third generation being shorter in nutrient-replete media. Parasites of hosts grown in nutrient-replete medium also produced three to four times more dinospores than those infecting hosts under low-nutrient conditions, with mean values of 380 and 130 dinospores/host, respectively. Dinospore production relative to host biovolume also differed, with peak values of 7.4 per 1,000 microm3 host for nutrient-replete medium and 4.8 per 1,000 microm3 host for nutrient-limited medium. Furthermore, dinospores produced by "high-nutrient" parasites had a higher success rate than those formed by "low-nutrient" parasites. Results suggest that Amoebophrya sp. is well adapted to exploit G. sanguineum populations in nutrient-enriched environments.

  5. Protease-associated cellular networks in malaria parasite Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Lilburn Timothy G

    2011-12-01

    Full Text Available Abstract Background Malaria continues to be one of the most severe global infectious diseases, responsible for 1-2 million deaths yearly. The rapid evolution and spread of drug resistance in parasites has led to an urgent need for the development of novel antimalarial targets. Proteases are a group of enzymes that play essential roles in parasite growth and invasion. The possibility of designing specific inhibitors for proteases makes them promising drug targets. Previously, combining a comparative genomics approach and a machine learning approach, we identified the complement of proteases (degradome in the malaria parasite Plasmodium falciparum and its sibling species 123, providing a catalog of targets for functional characterization and rational inhibitor design. Network analysis represents another route to revealing the role of proteins in the biology of parasites and we use this approach here to expand our understanding of the systems involving the proteases of P. falciparum. Results We investigated the roles of proteases in the parasite life cycle by constructing a network using protein-protein association data from the STRING database 4, and analyzing these data, in conjunction with the data from protein-protein interaction assays using the yeast 2-hybrid (Y2H system 5, blood stage microarray experiments 678, proteomics 9101112, literature text mining, and sequence homology analysis. Seventy-seven (77 out of 124 predicted proteases were associated with at least one other protein, constituting 2,431 protein-protein interactions (PPIs. These proteases appear to play diverse roles in metabolism, cell cycle regulation, invasion and infection. Their degrees of connectivity (i.e., connections to other proteins, range from one to 143. The largest protease-associated sub-network is the ubiquitin-proteasome system which is crucial for protein recycling and stress response. Proteases are also implicated in heat shock response, signal peptide

  6. Development and validation of PCR-based assays for diagnosis of American cutaneous leishmaniasis and identificatio nof the parasite species

    Directory of Open Access Journals (Sweden)

    Grazielle Cardoso da Graça

    2012-08-01

    Full Text Available In this study, PCR assays targeting different Leishmania heat-shock protein 70 gene (hsp70 regions, producing fragments ranging in size from 230-390 bp were developed and evaluated to determine their potential as a tool for the specific molecular diagnosis of cutaneous leishmaniasis (CL. A total of 70 Leishmania strains were analysed, including seven reference strains (RS and 63 previously typed strains. Analysis of the RS indicated a specific region of 234 bp in the hsp70 gene as a valid target that was highly sensitive for detection of Leishmania species DNA with capacity of distinguishing all analyzed species, after polymerase chain reaction-restriction fragment length polymorfism (PCR-RFLP. This PCR assay was compared with other PCR targets used for the molecular diagnosis of leishmaniasis: hsp70 (1400-bp region, internal transcribed spacer (ITS1 and glucose-6-phosphate dehydrogenase (G6pd. A good agreement among the methods was observed concerning the Leishmania species identification. Moreover, to evaluate the potential for molecular diagnosis, we compared the PCR targets hsp70-234 bp, ITS1, G6pd and mkDNA using a panel of 99 DNA samples from tissue fragments collected from patients with confirmed CL. Both PCR-hsp70-234 bp and PCR-ITS1 detected Leishmania DNA in more than 70% of the samples. However, using hsp70-234 bp PCR-RFLP, identification of all of the Leishmania species associated with CL in Brazil can be achieved employing a simpler and cheaper electrophoresis protocol.

  7. Development Aid and Growth: An association converging to zero

    DEFF Research Database (Denmark)

    Doucouliagos,, Hristos; Paldam, Martin

    report aid effects that have been steadily falling over time. The newer studies find a steady continuation of the downward trend. Using meta-regression analysis, we show that total aid has never had an effect on economic growth. Theoretically, this result might be due to simultaneity bias...

  8. Effect of selection for lean growth on gonadal development of ...

    African Journals Online (AJOL)

    A primary objective of commercial pig production is lean meat yield in order to satisfy consumer needs. The majority of the commercial pig breeds in South Africa have been selected for high lean growth potential and reduced backfat thickness. There are indications that selection for high lean meat yield may affect the ...

  9. Private Sector and Enterprise Development: Fostering Growth in the ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    31 janv. 2011 ... This important and well-researched book examines the challenges to private sector growth in 12 Middle East and North African countries, assessing comparative performance against a number of indicators and focusing on the special role of small and medium-sized enterprises (SMEs) and entrepreneurial ...

  10. Group Leader Development: Effects of Personal Growth and Psychoeducational Groups

    Science.gov (United States)

    Ohrt, Jonathan H.; Robinson, E. H., III; Hagedorn, W. Bryce

    2013-01-01

    The purpose of this quasi-experimental study was to compare the effects of personal growth groups and psychoeducational groups on counselor education students' (n = 74) empathy and group leader self-efficacy. Additionally, we compared the degree to which participants in each group valued: (a) cohesion, (b) catharsis, and (c) insight. There were no…

  11. Models of Economic Growth and Development in the Context of ...

    African Journals Online (AJOL)

    The better-known models of economic growth such as the Lewis, Rostow,. Harrod-Domar ... produce highly educated populaces usually reap the benefits of such in terms of high per capita ..... The Russian revolution of 1917 led by Lenin proposed in theory a .... This was about government intervention into the economy to ...

  12. Influence of plant growth regulators on development and ...

    African Journals Online (AJOL)

    Therefore propagation of the plant material by cell cultures and the extraction of potential pharmaceutical active compounds are of great interest. Calli were established on different media from roots and shoots of seedlings and softness and colour of the tissue were compared. Optimum growth of callus cultures was ...

  13. Growth and development of the reproductive organs of female ...

    African Journals Online (AJOL)

    The variation in the weight of the ovary probably reflects differences in the laying pattern of individuals, and this lends itself to simulating the ovulatory cycle and consequently gaining a better understanding of the process, which would in turn aid in determining the requirement for the nutrients responsible for the growth of ...

  14. 525 Population Growth, Hysteresis and Development Outcomes in ...

    African Journals Online (AJOL)

    technique of analysis is the Auto-Regressive Distributed Lag (ARDL) Bound test for long-run ..... Where; y is the actual income; λ is the adjustment factor and gy is output per ... income per capita if population growth leaves the ratio of workers to total ..... 0.00 and 0.01 probability values are not normally distributed around the.

  15. Disasters and development: natural disasters, credit constraints, and economic growth

    NARCIS (Netherlands)

    McDermott, T.K.J.; Barry, F.; Tol, R.S.J.

    2014-01-01

    Using a simple two-period model of the economy, we demonstrate the potential effects of natural disasters on economic growth over the medium to long term. In particular, we focus on the effect of such shocks on investment. We examine two polar cases: an economy in which agents have unconstrained

  16. Effect of generator (exhaust) fumes on the growth and development ...

    African Journals Online (AJOL)

    The leaf number per plant increased as the distance of the plants from the source of pollution increased with significant effects on plant from distance of 3 m and 6 m at the later stage of their growth (p < 0.05). Significant differences (p < 0.05) were observed among the plants in the different treatments for the different ...

  17. The current Russian model of social development, and economic growth

    Directory of Open Access Journals (Sweden)

    V V Paramonov

    2016-12-01

    Full Text Available Although the Article 7 of the Constitution of Russia adopted in 1993 defines the country as a social state, the contemporary social and economic situation is significantly different from this declaration. The author considers the current situation focusing on the foundations of the welfare state. The indicators of social inequality and stratification that allow to identify the country as a social state prove the widening gap between the rich and poor. In recent years, nothing has been done to achieve the more equitable distribution of income and national wealth, which led to the further growth of social inequality exceeding the global indices. The author believes that the high level of social inequality negatively affects the economic growth. Based on the studies of Russian scientists he concludes that equal distribution of income provides higher rates of economic growth and prosperity of the country. The modified theory of the factors of production explains this interconnection, and adds a few more factors, including such a specific resource as sales market, to three factors introduced by J.B. Say at the beginning of the XIX century. The huge social inequality and, consequently, a significant number of the poor deprive the country of such an important resource. To change the situation, the author proposes to return to the progressive tax scale and introduce the zero rate of income tax for the poorest groups in order to create prerequisites for the growth of consumer demand under the economic crisis.

  18. What founders in developing countries learn about organizing microenterprise growth

    DEFF Research Database (Denmark)

    Pötz, Katharina Anna; Hjortsø, Carsten Nico Portefée

    organizational failure. In this regard, we find that only those founders that rapidly make sense of ineffective processes, gain management knowledge from different sources, and devote time and energy to managerial tasks, manage to sustain organizational growth by learning to make ‘fixes’ for internal problems...

  19. road sector development and economic growth in ethiopia1

    African Journals Online (AJOL)

    Eyerusalem

    Regarding community roads, both the management and accountancy .... previous years and its impact on overall and sectoral economic growth. Descriptive analysis is deployed to capture the link between the road transport sector and performance indicators, like rural accessibility, road density, road network, road financing ...

  20. Road Sector Development and Economic Growth in Ethiopia ...

    African Journals Online (AJOL)

    The study attempts to see the trends, stock of achievements, and impact of road network on economic growth in Ethiopia. To do so, descriptive and econometric analyses are utilized. From the descriptive analysis, the findings indicate that the stock of road network is by now growing at an encouraging pace.

  1. AN ANALYSIS OF HUMAN CAPITAL DEVELOPMENT AND PRODUCTIVITY GROWTH- CASE STUDY, NIGERIA

    Directory of Open Access Journals (Sweden)

    Opeyemi Oluwabunmi Adejumo

    2017-09-01

    Full Text Available In order to address the direction of causality between human capital and productivity growth in Nigeria, the study first investigated the pattern of productivity growth in Nigeria between 1970 and 2010. Following the endogenous growth model, which argued that technical progress, through an effective labor force, could lead to long-run growth which can be determined from within an economy; but it actually depends on the efficiency with which resources available to such an economy are utilized. This is against the exogenous growth model which emphasized that long-run growth can be attained by some unexplained technological progress, which is exogenous to any economy. Based on this controversy in literature, this study empirically determined the productivity growth in Nigeria, as well as the causal relation between human capital development and productivity growth in Nigeria using the Engle-Granger causality test. The results revealed that productivity growth has been very low and unstable in Nigeria as it oscillated between -1.5% and 0.6%. In addition, the nexus between human capital and productivity growth was examined. The findings revealed that while productivity growth caused human capital development, human capital development did not cause productivity growth.

  2. Direction of Causality Between Financial Development and Economic Growth. Evidence for Developing Countries

    Directory of Open Access Journals (Sweden)

    Borlea Sorin Nicolae

    2016-06-01

    Full Text Available The results of extensive studies that analyzed the existence and meaning of correlations between the economic growth and the financial market development lead us to a more thorough study of these correlations. Therefore, we performed a broad study of the developing countries from around the world (the developing part of each region constructed by the World Bank through its Statistics Bureau. The regions taken into analysis were: Europe and Central Asia, South Asia, East Asia and the Pacific, the Arab world, Latin America & and the Caribbean, the Middle East and North Africa, and Sub-Saharan Africa. For comparison purposes, we have also included in the sample the North American countries, the Euro Area and the European Union as a whole, because these last three areas are the main benchmarks of the financial markets. The results are consistent with those from previous studies on the subject and vary depending on region and financial indicator considered.

  3. Plant hormone cytokinins control cell cycle progression and plastid replication in apicomplexan parasites.

    Science.gov (United States)

    Andrabi, Syed Bilal Ahmad; Tahara, Michiru; Matsubara, Ryuma; Toyama, Tomoko; Aonuma, Hiroka; Sakakibara, Hitoshi; Suematsu, Makoto; Tanabe, Kazuyuki; Nozaki, Tomoyoshi; Nagamune, Kisaburo

    2018-02-01

    Cytokinins are plant hormones that are involved in regulation of cell proliferation, cell cycle progression, and cell and plastid development. Here, we show that the apicomplexan parasites Toxoplasma gondii and Plasmodium berghei, an opportunistic human pathogen and a rodent malaria agent, respectively, produce cytokinins via a biosynthetic pathway similar to that in plants. Cytokinins regulate the growth and cell cycle progression of T. gondii by mediating expression of the cyclin gene TgCYC4. A natural form of cytokinin, trans-zeatin (t-zeatin), upregulated expression of this cyclin, while a synthetic cytokinin, thidiazuron, downregulated its expression. Immunofluorescence microscopy and quantitative PCR analysis showed that t-zeatin increased the genome-copy number of apicoplast, which are non-photosynthetic plastid, in the parasite, while thidiazuron led to their disappearance. Thidiazuron inhibited growth of T. gondii and Plasmodium falciparum, a human malaria parasite, suggesting that thidiazuron has therapeutic potential as an inhibitor of apicomplexan parasites. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Pitting of malaria parasites and spherocyte formation

    Directory of Open Access Journals (Sweden)

    Gichuki Charity W

    2006-07-01

    Full Text Available Abstract Background A high prevalence of spherocytes was detected in blood smears of children enrolled in a case control study conducted in the malaria holoendemic Lake Victoria basin. It was speculated that the spherocytes reflect intraerythrocytic removal of malarial parasites with a concurrent removal of RBC membrane through a process analogous to pitting of intraerythrocytic inclusion bodies. Pitting and re-circulation of RBCs devoid of malaria parasites could be a host mechanism for parasite clearance while minimizing the anaemia that would occur were the entire parasitized RBC removed. The prior demonstration of RBCs containing ring-infected erythrocyte surface antigen (pf 155 or RESA but no intracellular parasites, support the idea of pitting. Methods An in vitro model was developed to examine the phenomenon of pitting and spherocyte formation in Plasmodium falciparum infected RBCs (iRBC co-incubated with human macrophages. In vivo application of this model was evaluated using blood specimens from patients attending Kisumu Ditrict Hospital. RBCs were probed with anti-RESA monoclonal antibody and a DNA stain (propidium iodide. Flow cytometry and fluorescent microscopy was used to compare RBCs containing both the antigen and the parasites to those that were only RESA positive. Results Co-incubation of iRBC and tumor necrosis factor-alpha activated macrophages led to pitting (14% ± 1.31% macrophages with engulfed trophozoites as opposed to erythrophagocytosis (5.33% ± 0.95% (P Conclusion It is proposed that in malaria holoendemic areas where prevalence of asexual stage parasites approaches 100% in children, RBCs with pitted parasites are re-circulated and pitting may produce spherocytes.

  5. Linking parasite populations in hosts to parasite populations in space through Taylor's law and the negative binomial distribution.

    Science.gov (United States)

    Cohen, Joel E; Poulin, Robert; Lagrue, Clément

    2017-01-03

    The spatial distribution of individuals of any species is a basic concern of ecology. The spatial distribution of parasites matters to control and conservation of parasites that affect human and nonhuman populations. This paper develops a quantitative theory to predict the spatial distribution of parasites based on the distribution of parasites in hosts and the spatial distribution of hosts. Four models are tested against observations of metazoan hosts and their parasites in littoral zones of four lakes in Otago, New Zealand. These models differ in two dichotomous assumptions, constituting a 2 × 2 theoretical design. One assumption specifies whether the variance function of the number of parasites per host individual is described by Taylor's law (TL) or the negative binomial distribution (NBD). The other assumption specifies whether the numbers of parasite individuals within each host in a square meter of habitat are independent or perfectly correlated among host individuals. We find empirically that the variance-mean relationship of the numbers of parasites per square meter is very well described by TL but is not well described by NBD. Two models that posit perfect correlation of the parasite loads of hosts in a square meter of habitat approximate observations much better than two models that posit independence of parasite loads of hosts in a square meter, regardless of whether the variance-mean relationship of parasites per host individual obeys TL or NBD. We infer that high local interhost correlations in parasite load strongly influence the spatial distribution of parasites. Local hotspots could influence control and conservation of parasites.

  6. Cholesterol supplementation improves growth rates of Histomonas meleagridis in vitro.

    Science.gov (United States)

    Gruber, Janine; Pletzer, Alena; Hess, Michael

    2018-02-01

    Research on the energy metabolism of various protozoan parasites showed the essentiality and benefits of cholesterol in the cultivation of these organisms. However, not much is known about the energy metabolism of Histomonas meleagridis, although such information is of high importance to improve cultivation of the parasite for advancements in diagnostics, research and vaccine development. By supplementing a serum enriched cultivation medium with cholesterol, numbers of parasites could be doubled in comparison to unsupplemented negative controls. This effect was demonstrated for two different strains of the parasite, at different levels of in vitro-passages and for histomonads under xenic or monoxenic settings. Supplementing medium free of serum with cholesterol, resulted in significant growth of the parasite over 72 h. However, there were differences in growth behaviour in serum free medium between the different histomonad cultures and continuous passaging of the cultures without serum was not possible. Monitoring the bacterial growth of two different co-cultivated E. coli strains in monoxenic histomonad cultures during these experiments showed that there was no significant impact of cholesterol on the bacteria. Therefore, a direct effect of cholesterol on the parasite itself could be demonstrated. The results of these experiments supply new insights into the metabolism of H. meleagridis and it can be concluded that cholesterol is an important component to enhance parasite growth in vitro. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Growth, characterization and device development in monocrystalline diamond films

    Science.gov (United States)

    Davis, R. F.; Glass, J. T.; Nemanich, R. J.; Bozeman, S. P.; Sowers, A. T.

    1995-06-01

    Experimental and theoretical studies concerned with interface interactions of diamond with Si, Ni, and Ni3Si substrates have been conducted. Oriented diamond films deposited on (100) Si were characterized by polar Raman, polar x-ray diffraction (XRD), and cross-sectional high resolution transmission electron microscopy (HRTEM). These sutides showed that the diamond(100)/Si(100) interface adopted the 3:2-match arrangement rather than a 45 deg rotation. Extended Hueckel tight-binding (EHTB) electronic structure calculations for a model system revealed that the interface interaction favors the 3:2-match arrangement. Growth on polycrystalline Ni3Si resulted in oriented diamond particles; under the same growth conditions, graphite was formed on the nickel substrate. Our EHTB electronic structure calculations showed that the (111) and (100) surfaces of Ni3Si have a strong preference for diamond nucleation over graphite nucleation, but this was not the case for the (111) and (100) surfaces of Ni.

  8. Causality tests between stock market development and economic growth in West African Monetary Union

    Directory of Open Access Journals (Sweden)

    Maman Tachiwou ABOUDOU

    2009-12-01

    Full Text Available This paper examines the causal relationship between stock market development and economic growth for the West African Monetary Union economy over the last decade or so. By applying the techniques of unit–root tests and the long–run Granger noncausality test proposed by Toda and Yamamoto (1995, the causal relationships between the real GDP growth rate and two stock market development proxies are tested. The results are in line with the supply leading hypothesis in the sense that there is strong causal flow from the stock market development to economic growth. A unidirectional causal relationship is also observed between real market capitalization ratio and economic growth.

  9. Temperature effects on early season cotton growth and development

    International Nuclear Information System (INIS)

    Reddy, K.R.; Hodges, H.F.; Reddy, V.R.

    1992-01-01

    Temperature is a primary environmental factor controlling growth and developmental rates of plants, yet little specific information is available regarding cotton (Gossypium hisutum L.) responses to temperature. Information covering a wide range of temperatures would be useful for predicting both developmental and growth rates in cotton. Therefore, an experiment was conducted in naturally lit, temperature- and CO 2 -controlled cabinets from soon after emergence until 56 d after emergence (DAE). The cabinets were maintained at 20/12, 25/17, 30/22, 35/27, and 40/32C day/night cycles. Plant heights, number of nodes, and leaf areas were determined weekly throughout the experiment, and dry weight measurements were obtained at three intervals. Mainstem elongation, leaf area growth, and biomass accumulation rates were very sensitive to temperature about 3 wk after emergence. Prior to that time, they were relatively insensitive to temperature. The temperature optimum for stem elongation, leaf area expansion, and biomass accumulation was 30/22 C. Developmental rates, as depicted by number of mainstem nodes produced, number of fruiting branches, and fruiting branch nodes, were not as sensitive to temperatures above 30/22 C as were growth rates. Four times as many fruiting branches were produced at 30/22 C as at 20/12 C; whereas more vegetative branches were produced at low temperatures. All flower buds abscised from plants grown at 40/32 C. Essentially, all bolls and squares were retained at 30/22 C while a 10% boll and square loss was observed at 35/27 C during the early reproductive period. Less time was required for this cultivar to produce squares at any temperature, suitable for growing cotton, than was suggested by previous experiments

  10. Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

    Science.gov (United States)

    Emily J. Silver; Anthony W. D' Amato; Shawn Fraver; Brian J. Palik; John B. Bradford

    2013-01-01

    The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types....

  11. Information-communication technology impact on labor productivity growth of EU developing countries

    Directory of Open Access Journals (Sweden)

    Ljiljana Lovrić

    2012-12-01

    Full Text Available The aim of this study is to investigate the ICT impact on labor productivity growth of EU developing countries. Empirical studies of the role of ICT as one of the main determinants of productivity growth, for developing countries have produced disagreement. To help clear up the subject, this paper employs a Generalized Method of Moments (GMM through a dynamic panel data approach on the sample of 25 European developed and developing countries over the period of 2001-2010. The results indicate a positive and significant impact of ICT on labor productivity growth in developed and developing countries, but the terms of impact in developing countries rely on human capital, a contribution of a higher educational level, advanced research qualifications and development activity. Comparing to developed countries, the growth accounting approach indicate that developing countries have similar relative ICT contribution to labor productivity growth, but their average growth rate of labor productivity is 6.8 times higher. The main conclusion is that education, especially of higher levels, is the critical factor of productivity and growth of EU developing countries and that must be taken as development policy implication in these countries.

  12. Internal parasites of reptiles.

    Science.gov (United States)

    Raś-Noryńska, Małgorzata; Sokół, Rajmund

    2015-01-01

    Nowadays a growing number of exotic reptiles are kept as pets. The aim of this study was to determine the species of parasites found in reptile patients of veterinary practices in Poland. Fecal samples obtained from 76 lizards, 15 turtles and 10 snakes were examined by flotation method and direct smear stained with Lugol's iodine. In 63 samples (62.4%) the presence of parasite eggs and oocysts was revealed. Oocysts of Isospora spp. (from 33% to 100% of the samples, depending on the reptilian species) and Oxyurids eggs (10% to 75%) were predominant. In addition, isolated Eimeria spp. oocysts and Giardia intestinalis cysts were found, as well as Strongylus spp. and Hymenolepis spp. eggs. Pet reptiles are often infected with parasites, some of which are potentially dangerous to humans. A routine parasitological examination should be done in such animals.

  13. Linkages between financial development, financial instability, financial liberalisation and economic growth in Africa

    OpenAIRE

    Enowbi Batuo, M.; Mlambo, Kupukile; Asongu, Simplice

    2017-01-01

    In the aftermath of the 2008 global financial crisis, the implications of financial liberalisation for stability and economic growth has come under increased scrutiny. One strand of literature posits a positive relationship between financial liberalisation and economic growth and development. However, others emphasise the link between financial liberalisation is intrinsically associated with financial instability which may be harmful to economic growth and development. This study assesses ...

  14. Private sector development Aligning goals for economic growth and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2014-04-10

    Apr 10, 2014 ... In helping developing countries pursue private sector development strategies ... rates of entrepreneurship are generally much higher in developing ... Mini soap operas foster financial education and inclusion of women in Peru.

  15. Chicken or egg : financial development and economic growth in China, 1992-2004

    NARCIS (Netherlands)

    Fan, Xuejun; Jacobs, Jan; Lensink, Robert

    2005-01-01

    This paper contributes to the empirical finance-growth literature by examining the relationship between financial depth, banking sector development, stock market development and economic growth in China. After an extensive survey on recent financial reforms in China, we apply Granger (non-)causality

  16. Development of an attached microalgal growth system for biofuel production.

    Science.gov (United States)

    Johnson, Michael B; Wen, Zhiyou

    2010-01-01

    Algal biofuel production has gained a renewed interest in recent years but is still not economically feasible due to several limitations related to algal culture. The objective of this study is to explore a novel attached culture system for growing the alga Chlorella sp. as biodiesel feedstock, with dairy manure wastewater being used as growth medium. Among supporting materials tested for algal attachment, polystyrene foam led to a firm attachment, high biomass yield (25.65 g/m(2), dry basis), and high fatty acid yield (2.31 g/m(2)). The biomass attached on the supporting material surface was harvested by scraping; the residual colonies left on the surface served as inoculum for regrowth. The algae regrowth on the colony-established surface resulted in a higher biomass yield than that from the initial growth on fresh surface due to the downtime saved for initial algal attachment. The 10-day regrowth culture resulted in a high biodiesel production potential with a fatty acid methyl esters yield of 2.59 g/m(2) and a productivity of 0.26 g/m(-2) day(-1). The attached algal culture also removed 61-79% total nitrogen and 62-93% total phosphorus from dairy manure wastewater, depending on different culture conditions. The biomass harvested from the attached growth system (through scraping) had a water content of 93.75%, similar to that harvested from suspended culture system (through centrifugation). Collectively, the attached algal culture system with polystyrene foam as a supporting material demonstrated a good performance in terms of biomass yield, biodiesel production potential, ease to harvest biomass, and physical robustness for reuse.

  17. AFRICA’S DEVELOPMENT: INSTITUTIONS, ECONOMIC REFORMS AND GROWTH

    Directory of Open Access Journals (Sweden)

    Aloysius Ajab Amin

    2013-01-01

    Full Text Available The paper examines the importance of relative prices, institutional quality and other factors which are regressed on the estimated total factor productivity (TFP. With panel data of 26 African countries for the period 1980-2011, the results show that relative prices have significant effects on TFP. Also the quality of institutions is an important determinant of non-input component of output growth. The macroeconomic measures to get “prices right” in sub Saharan Africa may also be constrained by the linkages of institutions to the macroeconomic variables. Thus, policies of getting prices right with establishing strong institutions are worth continuously pursuing with vigor.

  18. Growth and remodeling play opposing roles during postnatal human heart valve development.

    Science.gov (United States)

    Oomen, Pim J A; Holland, Maria A; Bouten, Carlijn V C; Kuhl, Ellen; Loerakker, Sandra

    2018-01-19

    Tissue growth and remodeling are known to govern mechanical homeostasis in biological tissue, but their relative contributions to homeostasis remain unclear. Here, we use mechanical models, fueled by experimental findings, to demonstrate that growth and remodeling have different effects on heart valve stretch homeostasis during physiological postnatal development. Two developmental stages were considered: early-stage (from infant to adolescent) and late-stage (from adolescent to adult) development. Our models indicated that growth and remodeling play opposing roles in preserving tissue stretch and with time. During early-stage development, excessive tissue stretch was decreased by tissue growth and increased by remodeling. In contrast, during late-stage development tissue stretch was decreased by remodeling and increased by growth. Our findings contribute to an improved understanding of native heart valve adaptation throughout life, and are highly relevant for the development of tissue-engineered heart valves.

  19. Host and parasite morphology influence congruence between host and parasite phylogenies.

    Science.gov (United States)

    Sweet, Andrew D; Bush, Sarah E; Gustafsson, Daniel R; Allen, Julie M; DiBlasi, Emily; Skeen, Heather R; Weckstein, Jason D; Johnson, Kevin P

    2018-03-23

    Comparisons of host and parasite phylogenies often show varying degrees of phylogenetic congruence. However, few studies have rigorously explored the factors driving this variation. Multiple factors such as host or parasite morphology may govern the degree of phylogenetic congruence. An ideal analysis for understanding the factors correlated with congruence would focus on a diverse host-parasite system for increased variation and statistical power. In this study, we focused on the Brueelia-complex, a diverse and widespread group of feather lice that primarily parasitise songbirds. We generated a molecular phylogeny of the lice and compared this tree with a phylogeny of their avian hosts. We also tested for the contribution of each host-parasite association to the overall congruence. The two trees overall were significantly congruent, but the contribution of individual associations to this congruence varied. To understand this variation, we developed a novel approach to test whether host, parasite or biogeographic factors were statistically associated with patterns of congruence. Both host plumage dimorphism and parasite ecomorphology were associated with patterns of congruence, whereas host body size, other plumage traits and biogeography were not. Our results lay the framework for future studies to further elucidate how these factors influence the process of host-parasite coevolution. Copyright © 2018 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

  20. About teaching and bioecological importance of the increasing parasitic organisms

    International Nuclear Information System (INIS)

    Huseynova, L.S.

    2008-01-01

    The vital cycle of parasitic organisms borrows researches of duplication, development of special places in studing of fauna. The purpose of the presented work consists of what promote teachers of average schools to finish the pupil of data about duplication, development and vital cycles of parasitic organisms in wider, clean and clear form