نتایج جستجو برای: parasite numbers

تعداد نتایج: 234509  

Journal: :Folia parasitologica 2008
Peter D Walker Jack E Harris Gerard van der Velde Sjoerd E Wendelaar Bonga

In this study we examine differences in the occurrence of life history stages of the destructive fish ectoparasite Argulus foliaceus (L., 1758) on eight fish species (stickleback, rudd, roach, gudgeon, bream, tench, crucian carp and common carp) sampled from a mixed-species recreational fishing lake on nine occasions during late spring and summer. Total numbers ofA. foliaceus, as well as the nu...

2010
Gisela Llaveria Esther Garcés Oliver N. Ross Rosa Isabel Figueroa Nagore Sampedro Elisa Berdalet

Small-scale turbulence and parasite infection are 2 important factors that govern the dynamics and fate of phytoplankton populations. We experimentally investigated the influence of turbulent mixing on the infectivity of the parasite Parvilucifera sinerae to dinoflagellates. Natural phytoplankton communities were collected during 3 stages of a bloom event in Arenys de Mar Harbour (NW Mediterran...

Journal: :کنترل بیولوژیک آفات و بیماری های گیاهی 0
مریم راشکی گروه اکولوژی، پژوهشگاه علوم و تکنولوژی پیشرفته و علوم محیطی، دانشگاه تحصیلات تکمیلی صنعتی و فناوری پیشرفته، کرمان عزیز خرازی پاکدل گروه گیاهپزشکی، دانشکدة علوم و مهندسی کشاورزی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران، کرج حسین اللهیاری گروه گیاهپزشکی، دانشکدة علوم و مهندسی کشاورزی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران، کرج اصغر شیروانی گروه گیاهپزشکی، دانشکدة کشاورزی، دانشگاه شهید باهنر کرمان الهام رضوان نژاد گروه بیوتکنولوژی، پژوهشگاه علوم و تکنولوژی پیشرفته و علوم محیطی، دانشگاه تحصیلات تکمیلی صنعتی و فناوری پیشرفته، کرمان ژاک فن آلفن پژوهشگاه تنوع زیستی و دینامیک اکوسیستم، دانشگاه آمستردام، هلند

in this research, the effect of entomopathogenic fungus, beauveria bassiana (ascomycota, hypocreales), on functional response (in laboratory) and reproduction (in microcosm) of parasitoid wasp, aphidius matricariae haliday (hym.: braconidae) on its host, myzus persicae (sulzer) (hem.: aphididae) was investigated. illustrating number of mummified aphids versus initial density of green peach aphi...

2002
K. Wilson O. N. Bjørnstad A. P. Dobson S. Merler G. Poglayen S. E. Randolph A. F. Read A. Skorping

Animals vary markedly in the number of parasites they harbour-most have just a few, but some have many. In this chapter, we ask why there is so much variation between individuals, how do we quantify this variation and what are the consequences of these heterogeneities for the dynamics of the host-parasite interaction? 2.1 Background Exhaustive empirical surveys have shown that, almost without e...

Journal: :Infection and immunity 2000
M Belen Carrillo W Gao M Herrera J Alroy J B Moore S M Beverley M A Pereira

Earlier studies showed that mice primed for a few hours with the trans-sialidase (TS) of Trypanosoma cruzi, the agent of Chagas' disease, become highly susceptible to trypanosomal infection. These studies suggest that TS affects parasite virulence independent of antigenic stimulation. Potentially, TS could enhance or reduce the virulence of heterologous microbes depending on the mechanism of TS...

2010
Lilian Lacerda Bueno Cristiane Guimarães Morais Fernanda Fortes Araújo Juliana Assis Silva Gomes Rodrigo Corrêa-Oliveira Irene Silva Soares Marcus Vinícius Lacerda Ricardo Toshio Fujiwara Érika Martins Braga

Circulation CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) have been associated with the delicate balancing between control of overwhelming acute malaria infection and prevention of immune pathology due to disproportionate inflammatory responses to erythrocytic stage of the parasite. While the role of Tregs has been well-documented in murine models and P. falciparum infection, the phenotype a...

Journal: :Diseases of aquatic organisms 2017
Inês Fontes Hanna Hartikainen Jason W Holland Chris J Secombes Beth Okamura

Tetracapsuloides bryosalmonae is a myxozoan parasite of freshwater bryozoans and salmonids, causing proliferative kidney disease in the latter. To date, detection of the parasite has required collection of hosts and subsequent molecular or histological examination. The release of infectious spores from both hosts offers an opportunity to detect the parasite in water samples. We developed a nove...

2013
Jennifer L. Guler Daniel L. Freeman Vida Ahyong Rapatbhorn Patrapuvich John White Ramesh Gujjar Margaret A. Phillips Joseph DeRisi Pradipsinh K. Rathod

Malaria drug resistance contributes to up to a million annual deaths. Judicious deployment of new antimalarials and vaccines could benefit from an understanding of early molecular events that promote the evolution of parasites. Continuous in vitro challenge of Plasmodium falciparum parasites with a novel dihydroorotate dehydrogenase (DHODH) inhibitor reproducibly selected for resistant parasite...

Journal: :Parasitology 2013
Robert Poulin

Aggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data f...

Journal: :Infection and immunity 1986
S M Mahan L Hendershot S J Black

After infection with a cloned population of Trypanosoma vivax, C57BL/6 mice controlled parasitemia during the exponential growth phase and survived, with intermittent parasitemia, for several weeks. In contrast, most mice of the C3H/He strain did not control the first wave of parasitemia and died within 9 to 13 days after infection. Control of parasitemia in C57BL/6 mice was mediated by the pro...

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