1,623 research outputs found

    Host-parasite dialogue: fecundity compensation mechanisms of Fissurella crassa

    Get PDF
    Parasites can alter the reproductive performance of their hosts, and to avoid or mitigate the resulting fitness loss, hosts may increase their current reproductive output to compensate for the future loss due to the parasitic infection. Fecundity compensation can be exploited by parasites for their own transmission (exploitation of host compensatory responses by parasites). However, this phenomenon has rarely been reported in second intermediate hosts of trematodes and its mechanisms and consequences largely unexplored. Along the east coast of the South Pacific, the second intermediate host, the mollusk Fissurella crassa, has been observed to display higher muscular foot, greater shell length and weight, and a higher gonadosomatic index when parasitized by metacercariaes of Proctoeces humboldti compared to non-parasitized hosts. In this study, we examined the histology, biochemistry (glucose, lipids, and proteins), and levels of sex hormones (estradiol and progesterone) in both parasitized and non-parasitized female individuals of F. crassa. Our findings revealed that the gonad of parasitized limpets had a higher density of oocytes, but these had a smaller individual area. Additionally, the gonadal tissue of parasitized limpets exhibited lower glucose content but higher lipid content. Notably, the levels of progesterone increased with parasite intensity. These results suggest that F. crassa possesses the ability to compensate for the negative effects of parasites by increasing the number of oocytes through biochemical and hormonal mechanisms. Our study contributes to the limited research on the impact of metacercariae on the reproduction of second intermediate hosts. Furthermore, we discuss how these changes in parasitized limpets could benefit parasite transmission

    Evolutionary ecology of obligate fungal and microsporidian invertebrate pathogens

    Get PDF
    The interactions between hosts and their parasites and pathogens are omnipresent in the natural world. These symbioses are not only key players in ecosystem functioning, but also drive genetic diversity through co-evolutionary adaptations. Within the speciose invertebrates, a plethora of interactions with obligate fungal and microsporidian pathogens exist, however the known interactions is likely only a fraction of the true diversity. Obligate invertebrate fungal and microsporidian pathogen require a host to continue their life cycle, some of which have specialised in certain host species and require host death to transmit to new hosts. Due to their requirement to kill a host to spread to a new one, obligate fungal and microsporidian pathogens regulate invertebrate host populations. Pathogen specialisation to a single or very few hosts has led to some fungi evolving the ability to manipulate their host’s behaviour to maximise transmission. The entomopathogenic fungus, Entomophthora muscae, infects houseflies (Musca domestica) over a week-long proliferation cycle, resulting in flies climbing to elevated positions, gluing their mouthparts to the substrate surface, and raising their wings to allow for a clear exit from fungal conidia through the host abdomen. These sequential behaviours are all timed to occur within a few hours of sunset. The E. muscae mechanisms used in controlling the mind of the fly remain relatively unknown, and whether other fitness costs ensue from an infection are understudied.European Commissio

    Assessing the immunomodulatory and haemostatic role of platelets in the type 2 inflammatory response to Schistosoma mansoni

    Get PDF
    Beyond their role in haemostasis, platelets have been shown to be strongly immunomodulatory, particularly in type 1 inflammatory responses to bacteria and viruses. However, the role of platelets in type 2 inflammation, that characterises helminth infection and allergy is poorly understood. More than 200 million people globally are chronically infected with schistosome parasites which has a massive burden of >3 million disability adjusted life years. Despite large (~1cm long) worms residing in the vasculature for 5-10 years, they do not induce severe inflammation or coagulation. However, infected individuals display a plethora of debilitating symptoms including hepatosplenomegaly and intestinal haemorrhaging due to thousands of schistosome eggs transiting through and lodging within host tissues. This thesis aims to assess the haemostatic alterations and functional consequences of platelet-immune cell cross-talk in schistosomiasis. We used a murine model of chronic Schistosoma mansoni infection to examine specific platelet-leukocyte interactions and the effect these have on inflammation. Chronic schistosome infection induces thrombocytopenia (~500x10^3/mm^3) that persists after drug-mediated worm clearance. In vivo platelet tracking revealed accelerated hepatic and splenic platelet clearance in schistosome infection, and this occurred in an Fcő≥R-independent manner. Furthermore, there was a significant increase in platelets aggregating with specific hepatic macrophage subsets (Ly6Cň°ŠĶí MHCIIň°ŠĶí RELMőĪ į‚ĀĪ). Live cell imaging in vitro experiments revealed that platelets enhanced the phagocytic ability of M2 macrophages without altering MHCII or RELMőĪ expression. Surprisingly, platelets from schistosome-infected mice spontaneously aggregated in the absence of exogenous agonists despite not having an activated platelet phenotype, yet show prolonged clotting time. We used multiple experimental strategies to deplete or increase platelet numbers in schistosome infection, and this highlighted the challenges of separating the haemostatic and immunological roles of platelets in vivo. Work in this thesis demonstrates how schistosome infection disrupts platelet lifespan and functionality, whilst promoting enhanced interactions with immune cells

    Socio-environmental impacts of non-native and transplanted aquatic mollusc species in South America: What do we really know?

    Get PDF
    The impacts of biological invasions remain poorly known for some habitats, regions and taxa. To date, there has been no comprehensive effort to review and synthesize the impacts of invasive mollusc species in South America. In this paper, we provide a synoptic view on what is known on documented socio-ecological impacts of aquatic no-native mollusc species (NNMS) and transplanted mollusc species (TMS) from South America. An expert group involving malacologists and taxonomists from different countries, the ‚ÄúSouth America Alien Molluscs Specialists‚ÄĚ (eMIAS), shared and summarized the scientific literature, databases, and published and unpublished information on confirmed impacts of NNMS and TMS in South America. Three broad categories, non-mutually exclusive were used as a framework: ‚ÄúEnvironmental/Biodiversity impacts‚ÄĚ, ‚ÄúEconomic and social effects‚ÄĚ, and ‚ÄúHuman health impacts‚ÄĚ. Some 21 NNMS and seven TMS have documented impacts on at least one of those three categories. We encourage targeting the less known areas of research, such as economic valuation of human health (and veterinary) impacts attributable to NNMS or TMS and expand our knowledge of environmental impacts for the species listed in this study.Fil: Carranza, Alvar. Universidad de la Rep√ļblica; Uruguay. Museo Nacional de Historia Natural Uruguay; UruguayFil: Agudo Padr√≥n, Ignacio. Projeto ‚Äúavulsos Malacol√≥gicos‚ÄĚ; BrasilFil: Collado, Gonzalo A.. Universidad del Bio Bio; Chile. Sociedad Malacol√≥gica Chile; ChileFil: Damborenea, Maria Cristina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Divisi√≥n Zoolog√≠a Invertebrados; Argentina. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata; ArgentinaFil: Fabres, Alejandra. Sociedad Malacol√≥gica Chile; Chile. Universidad Cat√≥lica de Maule; ChileFil: Gutierrez Gregoric, Diego Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Divisi√≥n Zoolog√≠a Invertebrados; Argentina. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata; ArgentinaFil: Lodeiros, Cesar. Universidad T√©cnica de Manab√≠; Ecuador. Universidad de Oriente; VenezuelaFil: Ludwig, Sandra. Universidade Federal de Minas Gerais; BrasilFil: Pastorino, Roberto Santiago Guido. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Oficina de Coordinaci√≥n Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Oficina de Coordinaci√≥n Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Salvador, Rodrigo B.. Museum of New Zealand Te Papa Tongarewa,; Nueva Zelanda. The Artic University of Norway; NoruegaFil: Spotorno, Paula. Universidade Federal do Rio Grande; BrasilFil: Thiengo, Silvana. Fundaci√≥n Oswaldo Cruz; BrasilFil: Vidigal, Teofania Heloisa Dutra Amorim. Universidade Federal de Minas Gerais; BrasilFil: Darrigran, Gustavo Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Divisi√≥n de Zoolog√≠a Invertebrados; Argentina. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata; Argentin

    IL-4 induces CD22 expression to restrain the effector program of self-reactive virtual memory T cells

    Full text link
    Abstract Parasitic helminths induce the production of interleukin (IL)-4 which causes the expansion of virtual memory CD8+ T cells (Tvm), a cell subset contributing to the control of viral coinfection. However, the mechanisms regulating IL-4-dependent Tvm activation and expansion during worm infection remain ill defined. We used single-cell RNA sequencing of CD8+ T cells to investigate IL-4-dependent Tvm responses upon helminth infection in mice. Gene signature analysis of CD8+ T cells identified a cell cluster marked by CD22, a canonical regulator of B cell activation, as a specific and selective surface marker of IL-4-induced Tvm cells. CD22+ Tvm were enriched for IFN-ő≥ and granzyme A and retained a diverse TCR repertoire, while enriched in CDR3 sequences with features of self-reactivity. Deletion of CD22 expression in CD8+ T cells enhanced Tvm responses to helminth infection, indicating that this inhibitory receptor modulates Tvm responses. Thus, helminth-induced IL-4 drives the expansion and activation of self-reactive Tvm in the periphery that is counter-inhibited by CD22

    Seasonal patterns of Schistosoma mansoni infection within Biomphalaria snails at the Ugandan shorelines of Lake Albert and Lake Victoria

    Get PDF
    Intestinal schistosomiasis is hyperendemic in many sub-Saharan African countries. In Uganda, it is endemic at both Lake Albert (LA) and Lake Victoria (LV) and caused by S. mansoni that uses Biomphalaria snails as obligatory intermediate snail hosts. To shed light on local patterns of infection, we utilised two PCR-based methods to detect S. mansoni within Biomphalaria spp. as collected at the Ugandan shorelines of Lake Albert and Lake Victoria from 2009‚Äď2010. Overall, at our Lake Albert sites, the mean infection prevalence was 12.5% (15 of 120 snails), while at our Lake Victoria sites the prevalence was 5% (3 of 60 snails). At our Lake Albert sites, the highest infection prevalence of 13.3% (8 of 60 snails) was at Walukuba, while at our Lake Victoria sites, the highest infection prevalence of 10% (2 of 20 snails) was at Lwanika. Three species of Biomphalaria, B. pfeifferi, B. stanleyi and B. sudanica, were identified at our Lake Albert collection sites, while only a single species, B. choanomphala, was identified at our Lake Victoria collection sites. Biomphalaria stanleyi (2 of 20 snails; 15%) had the highest infection prevalence, followed by B. sudanica (5 of 60 snails; 13.3%), B. pfeifferi (4 of 40 snails; 10%) and B. choanomphala (3 of 60 snails; 5%). Of the Biomphalaria species identified, B. choanomphala had the highest haplotype (gene) diversity score, followed by B. stanleyi, B. sudanica and B. pfeifferi. Sites with a higher mean prevalence of S. mansoni infection had higher intra-species haplotype diversity scores than sites with a lower mean prevalence. The wet seasons (LA: 13.3%; LV: 8.7%) had a consistently higher mean infection prevalence of S. mansoni than the dry seasons (LA: 9.5%; LV: 5%) for all species and all sites tested at both Lake Albert (n = 480) and Lake Victoria (n = 320), though the difference was not statistically significant

    Influence of exposure Heterorhabditis bacteriophora HP88, (Rhabditida: Heterorhabditidae) on biological and physiological parameters of Pseudosuccinea columella (Basommatophora: Lymnaeidae)

    Get PDF
    Abstract Many studies about fasciolosis control have been carried out, whether acting on the adult parasite or in Pseudosuccinea columella, compromising the development of the larval stages. The present study aimed to evaluate, under laboratory conditions, the susceptibility of P. columella to Heterorhabditis bacteriophora HP88, during for 24 and 48 hours of exposure. The snails were evaluated for 21 days for accumulated mortality; number of eggs laid; hatchability rate; biochemical changes; and histopathological analysis. We found that exposure induced a reduction in glucose and glycogen levels, characterizing a negative energy balance, due to the depletion of energy reserves as a result of the direct competition established by the nematode/endosymbiont bacteria complex in such substrates. A mortality rate of 48.25% and 65.52% was observed in the group exposed for 24 h and 48 h, respectively, along with significant impairment of reproductive biology in both exposed groups in relation to the respective controls. The results presented here show that P. columella is susceptible to the nematode H. bacteriophora, with the potential to be used as an alternative bioagent in the control of this mollusk, especially in areas considered endemic for fascioliasis, in line with the position expressed by the World Health Organization Health

    The development, constitution and functions of the gland apparatus in schistosome cercariae and endopeptidases in its contents

    Get PDF
    Flukes of the family Schistosomatidae are blood parasites with two-host life cycles involving aquatic snails as intermediate hosts and avian or mammalian definitive hosts. Cercariae, as invasive aquatic stages of schistosomes, enter the lumen of vessels by penetrating the skin of the definitive host. During their short life, cercariae possess a glandular apparatus consisting of three types of glands with external secretion: penetration glands, escape glands, and a head gland. These glands secrete granules containing, among other things, proteolytic enzymes, which play an important role in the process of penetrating the host's skin, but at the same time they occupy many other functions during the life of the cercaria and other life stages of schistosomes. This thesis summarizes basic knowledge about the anatomy, function and development of the gland apparatus of schistosome cercariae and further focuses on the representation of proteolytic enzymes in these glands, specifically endopeptidases. At the end, it briefly compares the different representation of endopeptidases in some members of the family.Motolice ńćeledi Schistosomatidae jsou krevn√≠ parazit√© s dvouhostitelsk√Ĺmi Ňĺivotn√≠mi cykly zahrnuj√≠c√≠mi vodn√≠ plŇĺe jako mezihostitele a definitivn√≠ hostitele z Ňôad pt√°kŇĮ ńći savcŇĮ. Cerk√°rie jakoŇĺto invazivn√≠ vodn√≠ st√°dia schistosom se do lumen c√©v dost√°vaj√≠ penetrac√≠ kŇĮŇĺe definitivn√≠ho hostitele. V prŇĮbńõhu sv√©ho kr√°tk√©ho Ňĺivota disponuj√≠ cerk√°rie Ňĺl√°zov√Ĺm apar√°tem sest√°vaj√≠c√≠m ze tŇô√≠ typŇĮ Ňĺl√°z s vnńõjŇ°√≠ sekrec√≠: penetrańćn√≠ch Ňĺl√°z, √ļnikov√Ĺch Ňĺl√°z a hlavov√© Ňĺl√°zy. Tyto Ňĺl√°zy vyluńćuj√≠ sekretorick√° granula obsahuj√≠c√≠ mimo jin√© proteolytick√© enzymy, kter√© hraj√≠ dŇĮleŇĺitou roli v procesu penetrace kŇĮŇĺe hostitele, ale z√°roveŇą zauj√≠maj√≠ mnoho dalŇ°√≠ch funkc√≠ v prŇĮbńõhu Ňĺivota cerk√°rie i dalŇ°√≠ch Ňĺivotn√≠ch st√°di√≠ schistosom. Tato pr√°ce shrnuje z√°kladn√≠ poznatky o anatomii, funkci a v√Ĺvoji Ňĺl√°zov√©ho apar√°tu cerk√°ri√≠ schistosom a d√°le se zamńõŇôuje na zastoupen√≠ proteolytick√Ĺch enzymŇĮ v tńõchto Ňĺl√°z√°ch, konkr√©tnńõ endopeptid√°z. Na z√°vńõr struńćnńõ porovn√°v√° rozd√≠ln√© zastoupen√≠ endopeptid√°z u rŇĮzn√Ĺch z√°stupcŇĮ ńćeledi.Katedra parazitologieDepartment of ParasitologyFaculty of SciencePŇô√≠rodovńõdeck√° fakult

    2010 GREAT Day Program

    Get PDF
    SUNY Geneseo’s Fourth Annual GREAT Day. This file has a supplement of three additional pages, linked in this record.https://knightscholar.geneseo.edu/program-2007/1004/thumbnail.jp
    • ‚Ķ