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1.
Aim Populations of free‐living vertebrates on islands frequently differ from their mainland counterparts by a series of changes in morphometric, life‐history, behavioural, physiological and genetic traits, collectively referred to as the ‘island syndrome’. It is not known, however, whether the ‘island syndrome’ also affects parasitic organisms. The present study establishes the colonization pattern of the Mediterranean islands by the nematode Heligmosomoides polygyrus, a direct and specific parasite of rodent hosts of the Apodemus genus, and evaluates the effects of island colonization by this species on two components of the island syndrome: the loss of genetic diversity and the enlargement of the ecological niche. Location Heligmosomoides polygyrus was sampled on seven western Mediterranean islands ? Corsica, Crete, Elba, Majorca, Minorca, Sardinia and Sicily ? as well as in 20 continental locations covering the Mediterranean basin. Methods The mitochondrial cytochrome b gene (690 base pairs) was sequenced in 166 adult H. polygyrus individuals sampled in the 27 continental and island locations. Phylogenetic reconstructions in distance, parsimony, maximum likelihood and Bayesian posterior probabilities were carried out on the whole cytochrome b gene data set. The levels of nucleotide, haplotype and genetic divergence (Kimura two‐parameter distance estimator) diversities were estimated in each island population and in the various continental lineages. Results Phylogenetic reconstructions show that the mainland origins of H. polygyrus were continental Spain for the Balearic Islands (Majorca, Minorca), northern Italy for the Tyrrhenian Islands (Corsica, Sardinia, Elba), southern Italy for Sicily, and the Balkan region for Crete. A comparison of island H. polygyrus populations with their mainland source populations revealed two characteristic components of the island syndrome in this parasite. First, island H. polygyrus populations display a significant loss of genetic diversity, which is related (r2 = 0.73) to the distance separating the island from the mainland source region. Second, H. polygyrus exhibits a niche enlargement following insularization. Indeed, H. polygyrus in Corsica is present in both A. sylvaticus and Mus musculus domesticus, while mainland H. polygyrus populations are present exclusively in Apodemus hosts. Main conclusions Our results show that H. polygyrus has undergone a loss of genetic diversity and a niche (host) enlargement following colonization of the western Mediterranean islands. To our knowledge, this study provides the first evidence for components of the ‘island syndrome’ in a parasitic nematode species.  相似文献   

2.
A total of 1,708 small mammals (1,617 rodents and 91 soricomorphs), including Apodemus agrarius (n = 1,400), Microtus fortis (167), Crocidura lasiura (91), Mus musculus (32), Myodes (= Eothenomys) regulus (9), Micromys minutus (6), and Tscherskia (= Cricetulus) triton (3), were live-trapped at US/Republic of Korea (ROK) military training sites near the demilitarized zone (DMZ) of Paju, Pocheon, and Yeoncheon, Gyeonggi Province from December 2004 to December 2009. Small mammals were examined for their intestinal nematodes by necropsy. A total of 1,617 rodents (100%) and 91 (100%) soricomorphs were infected with at least 1 nematode species, including Nippostrongylus brasiliensis, Heligmosomoides polygyrus, Syphacia obvelata, Heterakis spumosa, Protospirura muris, Capillaria spp., Trichuris muris, Rictularia affinis, and an unidentified species. N. brasiliensis was the most common species infecting small mammals (1,060; 62.1%) followed by H. polygyrus (617; 36.1%), S. obvelata (370; 21.7%), H. spumosa (314; 18.4%), P. muris (123; 7.2%), and Capillaria spp. (59; 3.5%). Low infection rates (0.1-0.8%) were observed for T. muris, R. affinis, and an unidentified species. The number of recovered worms was highest for N. brasiliensis (21,623 worms; mean 20.4 worms/infected specimen) followed by S. obvelata (9,235; 25.0 worms), H. polygyrus (4,122; 6.7 worms), and H. spumosa (1,160; 3.7 worms). A. agrarius demonstrated the highest prevalence for N. brasiliensis (70.9%), followed by M. minutus (50.0%), T. triton (33.3%), M. fortis (28.1%), M. musculus (15.6%), C. lasiura (13.2%), and M. regulus (0%). This is the first report of nematode infections in small mammals captured near the DMZ in ROK.  相似文献   

3.
To determine geographical patterns of natural parasite infections among wild rodents, a total of 46 wild rodents from 3 different localities in northern Gangwon-do (Province), Korea were examined for intestinal parasite infections. Along with nematodes such as hookworms and Syphacia spp., Plagiorchis muris (2 specimens) (Trematoda) were collected from striped field mice, Apodemus agrarius. In a Korean wood mouse, Apodemus peninsulae, the overall nematode infections were similar to A. agrarius, but an adult worm of Echinostoma hortense (Trematoda) was collected. In addition, 2 species of cestodes, i.e., Hymenolepis nana and Hymenolepis diminuta, were collected from A. agrarius. Through this survey, A. agrarius and A. peninsule were confirmed as the natural definite hosts for zoonotic intestinal helminths, i.e., P. muris, E. hortense, H. nana, and H. diminuta, in northern Gangwon-do, Korea. Considering increased leisure activities around these areas, seasonal and further comprehensive surveys on wild rodents seem to be needed to prevent zoonotic parasite infections.  相似文献   

4.
Heligmosomoides polygyrus (formerly known as Nematospiroides dubius, and also referred to by some as H. bakeri) is a gastrointestinal helminth that employs multiple immunomodulatory mechanisms to establish chronic infection in mice and closely resembles prevalent human helminth infections. H. polygyrus has been studied extensively in the field of helminth-derived immune regulation and has been found to potently suppress experimental models of allergy and autoimmunity (both with active infection and isolated secreted products). The protocol described in this paper outlines management of the H. polygyrus life cycle for consistent production of L3 larvae, recovery of adult parasites, and collection of their excretory-secretory products (HES).  相似文献   

5.
Primary exposure of mice to gastrointestinal nematode infection with Heligmosomoides polygyrus reduces inflammation in an experimental model of multiple sclerosis. In this study, we aimed to evaluate the ability of H. polygyrus L4 larvae and adults infection to reduce the symptoms of ongoing experimental autoimmune encephalomyelitis (EAE) in female C57Bl/6 mice. EAE was induced by myelin oligodendrocyte glycoprotein MOGp35–55 and after 21 days mice were orally infected with 200 infective larvae (L3) of H. polygyrus. Reduction in EAE symptoms was observed from 2 days post infection and the symptoms were almost completely inhibited at 6 days post infection. This effect was associated with limited total protein content in the cerebrospinal fluid; CSF, and significant decreased pro-inflammatory IL-12p40 concentration and increased concentration of the regulatory cytokines IL-10, TGF-β and IL-6 in the CSF and in the serum. The reduction of EAE symptoms in the enteral phase was associated with higher IL-12p40 concentration in the CSF and very low concentrations of IL-17A and IL-2 in the serum. The fourth stage of gastrointestinal nematode can reverse systemic inflammation in animal models of multiple sclerosis by reducing IL-12 and promoting regulatory cytokines production. The mechanism induced by adult nematodes which sustained EAE inhibition can be provoked by regulatory mechanism connected with reduce IL-17A concentration.  相似文献   

6.
Glutathione S-transferases have been partially characterised from the gastrointestinal nematode Heligmosomoides polygyrus. Two major subunit families were purified (24 and 23 kDa) with N-terminal homology to the mammalian Alpha family. Four dimeric forms of GST were purified from the nematode by glutathione-affinity chromatography, two major enzymes (pI 8.1, 5.0) and two minor forms (pI 5.8, 5.3). The purified GST pool could neutralize model and lipid peroxides via peroxidase activity but not peroxidation derived reactive carbonyls via glutathione transferase activity. Antisera raised to the pooled nematode GSTs appeared to recognize other Strongylida GSTs more strongly on Western blotting compared to mammalian GSTs.  相似文献   

7.
Approximately 2 billion people worldwide and a significant part of the domestic livestock are infected with soil-transmitted helminths, of which many establish chronic infections causing substantial economic and welfare burdens. Beside intensive research on helminth-triggered mucosal and systemic immune responses, the local mechanism that enables infective larvae to cross the intestinal epithelial barrier and invade mucosal tissue remains poorly addressed. Here, we show that Heligmosomoides polygyrus infective L3s secrete acetate and that acetate potentially facilitates paracellular epithelial tissue invasion by changed epithelial tight junction claudin expression. In vitro, impedance-based real-time epithelial cell line barrier measurements together with ex vivo functional permeability assays in intestinal organoid cultures revealed that acetate decreased intercellular barrier function via the G-protein coupled free fatty acid receptor 2 (FFAR2, GPR43). In vivo validation experiments in FFAR2?/? mice showed lower H. polygyrus burdens, whereas oral acetate-treated C57BL/6 wild type mice showed higher burdens. These data suggest that locally secreted acetate – as a metabolic product of the energy metabolism of H. polygyrus L3s – provides a significant advantage to the parasite in crossing the intestinal epithelial barrier and invading mucosal tissues. This is the first and a rate-limiting step for helminths to establish chronic infections in their hosts and if modulated could have profound consequences for their life cycle.  相似文献   

8.
Apyrases are a recurrent feature of secretomes from numerous species of parasitic nematodes. Here we characterise the five apyrases secreted by Heligmosomoides polygyrus, a natural parasite of mice and a widely used laboratory model for intestinal nematode infection. All five enzymes are closely related to soluble calcium-activated nucleotidases described in a variety of organisms, and distinct from the CD39 family of ecto-nucleotidases. Expression is maximal in adult worms and restricted to adults and L4s. Recombinant apyrases were produced and purified from Pichia pastoris. The five enzymes showed very similar biochemical properties, with strict calcium dependence and a broad substrate specificity, catalysing the hydrolysis of all nucleoside tri- and diphosphates, with no activity against nucleoside monophosphates. Natural infection of mice provoked very low antibodies to any enzyme, but immunisation with an apyrase cocktail showed partial protection against reinfection, with reduced egg output and parasite recovery. The most likely role for nematode secreted apyrases is hydrolysis of extracellular ATP, which acts as an alarmin for cellular release of IL-33 and initiation of type 2 immunity.  相似文献   

9.
Neilson J.T. McL., Forrester D.J. and Thompson N.P. 1973. Immunologic studies on Heligmosomoides polygyrus infection in the mouse: The dynamics of single and multiple infections and the effect of DDT upon acquired resistance. International Journal for Parasitology3: 371–378. Swiss Webster mice were given infections of 100,200, 300 and 400 Heligmosomoides polygyrus (= Nematospiroides dubius) larvae respectively at intervals of 4 weeks. Where appropriate, the preceding infection was terminated with anthelmintic 7 days prior to the subsequent infection. Animals were killed at regular inteivals following each infection and the worm burdens compared with those found in control mice given a primary infection of similar size. The expulsion of worms in mice given three previous infections occurred after day 3 and before day 7 postinfection indicating that those larvae moulting from the fourth to fifth stages may be most susceptible to the host's resistance mechanisms. The administration of p,p'-DDT to hyperinfected mice did not interfere with the immunologic expulsion of worms.  相似文献   

10.
Many laboratory studies and epidemiological observations confirm that nematodes prevent some immune-mediated diseases. The development of immunologically well-defined laboratory models of intestinal nematode infection has allowed significant advances to be made in understanding the immunological basis of effector mechanisms operating during infection under controlled laboratory conditions. The Heligmosomoides polygyrus- mouse system is used for studies of parasite immunomodulation. H. polygyrus causes a chronic, asymptomatic intestinal infection and effectively maintains both local and systemic tolerance to reduce allergic and autoimmune inflammation. However, exposure of mice to H. polygyrus antigen reduced spontaneous and glucocorticoid-induced apoptosis of CD4- positive T cells in mesenteric lymph node (MLN). In this study we evaluate the proliferation, cytokine secretion, cell cycle progression and expression of apoptosis related genes in MLN CD4 T cells of uninfected and H. polygyrus infected mice ex vivo and in vitro after restimulation with parasite excretory secretory antigen (ESAg), somatic antigen (SAg) and fraction 9 (F9Ag) of somatic antigen. For the first time we explain the influence of H. polygyrus antigens on the intrinsic pathway of apoptosis. We found that the proliferation provoked by fraction 9 and inhibition of apoptosis was dependent on a low Bax/Bcl-2 ratio, dramatical upregulation of survivin, D1 cyclin, P-glycoprotein, and loss of p27Kip1 protein with inhibition of active caspase-3 but not caspase- 8.  相似文献   

11.
Nematode spermatozoa are amoeboid cells. In Caernorhabditis elegans and Ascaris suum, previous studies have reported that sperm motility does not involve actin, but, instead, requires a specific cytoskeletal protein, name y major-sperm-protein (MSP). In Heligmosomoides polygyrus, a species with large and elongate spermatids and spermatozoa, cell organelles are easily identified even with light microscopy. Electrophoresis of Heligmosomoides sperm proteins indicates that the main protein band has a molecular weight of about 15 kDa, as MSP in other nematodes, and is specifically labelled by an anti-MSP antibody raised against C. elegans MSP. A minor band at 43 kDa was specifically labelled by an anti-actin antibody. Reaction of anti-actin and anti-MSP antibodies is specific to, and restricted to, their respective targets. Actin and MSP localisation, studied by indirect immunofluorescence in male germ cells of Heligmosomoides polygyrus, are similar: spermatids show rows of dots, corresponding to the fibrous bodies, around an unlabelled central longitudinal core; spermatozoa are labelled strictly in an anterior crescent-shaped cap, at the opposite pole to the nucleus, which contains fibres of the MSP cytoskeleton. Phalloidin labelling shows that F-actin is present in spermatids, but absent in spermatozoa. Tropomyosin shows a distinct pattern in spermatids, but is located in the MSP and actin-containing cap in spermatozoa. It is hypothesized that actin plays a role in the shaping of the cell and in the arrangement of its organelles during nematode spermiogenesis, when MSP is present, in an inactive state, in the fibrous bodies. The concentration of actin and tropomyosin in the anterior cap is not compatible with previous theories about the MSP cytoskeleton which is supposed to act in the absence of actin. © 1996 Wiley-Liss, Inc.  相似文献   

12.
Mice infected with 200 to 300 Heligmosomoides polygyrus had reduced serum hemagglutinin titers following a series of oral inoculations of sheep erythrocytes (SRBC) when compared to similarly inoculated uninfected mice. Study of antibody-producing cells by the indirect hemolytic plaque technique demonstrated a low splenic response to oral immunization in which IgA predominated. No alteration was evident in the proportions of antibody-containing cells in the different Ig classes with infection. Comparison of the immune response to oral and intraperitoneal routes of SRBC inoculation in infected and uninfected mice demonstrated a similar reduction in antibody titer with both routes of inoculation, although immunosuppression following intraperitoneal inoculations was not consistantly observed. The data are discussed in relation to the influence of the helminth infection on intestinal immune response and systemic immune response.  相似文献   

13.
Hp-FAR-1 is a major, secreted antigen of the parasitic nematode Heligmosomoides polygyrus, a laboratory mouse model frequently used to study the cellular mechanisms of chronic helminth infections. The DNA encoding Hp-FAR-1 was recovered by screening a fourth larval (L(4)) H. polygyrus cDNA expression library using antibodies raised against L(4) stage excretory/secretory (E/S) proteins. Predictions of secondary structure based on the Hp-FAR-1 amino acid sequence indicated that an alpha-helix predominates in Hp-FAR-1, possibly with some coiled-coil conformation, with no beta-structure. Fluorescence-based ligand binding analysis confirmed that the recombinant Hp-FAR-1 (rHp-FAR-1) binds the fluorescent fatty acid analog 11-((5-[dimethylaminoaphthalene-1-sulfonyl)amino)undecanoic acid (DAUDA), and by competition oleic acid. RT-PCR amplification of the hp-far-1 gene indicated that the gene is transcribed in all parasitic stages of the organism's life cycle. The presence of a secreted FAR protein in the well-defined laboratory model of H. polygyrus provides an excellent model for the further study and analysis of the in vivo role of secreted FAR proteins in parasitism, and supports the mounting evidence that secreted FAR proteins play a major role in nematode parasitism.  相似文献   

14.
A total of 1,498 small mammals (rodents and insectivores), including Apodemus agrarius (n = 1,366), Crocidura lasiura (54), Mus musculus (32), Micronytus fortis (28), Eothenomys regulus (9), Micronys minutes (6), and Cricetulus triton (3), were live-trapped in Gyeonggi-do (Province) (Paju-si, Pocheon-gun, and Yeoncheon-gun) near the demilitarized zone (DMZ) from December 2004 to September 2005. A. agrarius was found to be infected with 3 species of echinostomes (Echinostoma hortense, Echinostoma cinetorchis, and Euparyphium murinum), while C. lasiura was infected with 1 species (Echinochasmus japonicas) of echinostome. Other mammals were free from echinostome infections. Total 16 E. hortense were detected in 7 (0.5%) mice, 9 E. cinetorchis from 5 (0.4%), and 3 E. murinum from 2 (0.1%) out of 1.366 A. agrarius examined. E. japonicus was found only in 1 (1.9%; total 3 specimens) C. lasiura. These results demonstrate that A. agrarius and C. lasiura, inhabiting near the DMZ of Gyeonggi-do serve as the natural definitive hosts for several species of echinostomes, although their infection rates are low. This is the first record of natural infections of A. agrarius with E. cinetorchis and C. lasiura with E. japonicus in the Republic of Korea.  相似文献   

15.
Coinfections with parasitic helminths and microparasites are highly common in nature and can lead to complex within-host interactions between parasite species which can cause negative health outcomes for humans, and domestic and wild animals. Many of these negative health effects worsen with increasing parasite burdens. However, even though many studies have identified several key factors that determine worm burdens across various host systems, less is known about how the immune response interacts with these factors and what the consequences are for the outcome of within-host parasite interactions. We investigated two interacting gastrointestinal parasites of wild wood mice, Heligmosomoides polygyrus (nematode) and Eimeria spp. (coccidia), in order to investigate how host demographic factors, coinfection and the host’s immune response affected parasite burdens and infection probability, and to determine what factors predict parasite-specific and total antibody levels. We found that antibody levels were the only factors that significantly influenced variation in both H. polygyrus burden and infection probability, and Eimeria spp. infection probability. Total faecal IgA was negatively associated with H. polygyrus burden and Eimeria spp. infection, whereas H. polygyrus-specific IgG1 was positively associated with H. polygyrus infection. We further found that the presence of Eimeria spp. had a negative effect on both faecal IgA and H. polygyrus-specific IgG1. Our results show that even in the context of natural demographic and immunological variation amongst individuals, we were able to decipher a role for the host humoral immune response in shaping the within-host interaction between H. polygyrus and Eimeria spp.  相似文献   

16.
Although the caterpillars are well-known for the stings and magnificent coloration, the systematics of Limacodidae is historically neglected and chaotic due to the difficulty in matching the larval with adult stages as well as the very conservative and convergent adult morphology. One of the biggest taxonomic problems surrounds a collective group from Southeastern Asia, termed the “green limacodid moths”, which harbours at least 90 species placed in the genus Parasa Walker, 1859 and 14 “subunits”. The P. undulata group was previously composed of 3 species from China and Taiwan, and characterized only by wing pattern. This species group is extensively studied herein with two new species described, i.e. P. viridiflamma sp. n. (Taiwan) and P. minwangi sp. n. (S. China), and discovery of female genitalia of three species, presenting new phylogenetic insights in this potentially paraphyletic genus. In addition, one limacodid larva was found to be feeding exclusively on Picea (Pinaceae) in Taiwan. Its identity, Parasa pygmy Solovyev, 2010 in P. undulata group, is confirmed through matching its COI sequence to the adult. This discovery is also biologically significant because the previous known host breadth of Parasa was of polyphagy on various angiosperm plant families. This case, therefore, represents the first record of conifer-feeding behavior in this family as well as the first of specialized herbivory in the genus. Meanwhile, the background match between Picea leaves and larval coloration is shared with other Picea-feeding insects. This phenomenon is worth of further investigation in the aspect of convergent evolution of crypsis associated with a particular plant.  相似文献   

17.
Uwe Kallweit 《ZooKeys》2013,(269):11-32
The distribution of Acomopterella species in the Palaearctic region has been re-examined in this study, using recently collected material. The European species was found to be distributed in the eastern Palaearctic as well. A second Palaearctic species from Honshu (Japan) is herein described. The morphology of adult specimens was studied by light microscopy and scanning electron microscopy. The shape of functional specialized setae on mid tibiae in Acomopterella and seven further fungus gnat genera is described and the suitability of this character for systematic studies is discussed. Details of a “hind tibial organ” are described.The position of Acomopterella in the tribe Gnoristini is briefly discussed. Acomopterella is found to be more closely related to Speolepta Edwards, 1925, than to any other recent genus.  相似文献   

18.
A new species, Cherax snowden sp. n., from the Oinsok River Drainage, Sawiat District in the central part of the Kepala Burung (Vogelkop) Peninsula, West Papua, Indonesia, is described, figured and compared with the closest related species, Cherax holthuisi Lukhaup & Pekny, 2006. This species is collected and exported for ornamental purposes and its commercial name in the pet trade is “orange tip” or “green orange tip”. Both species may be easily distinguished morphologically or by using sequence divergence, which is substantial, for considering Cherax snowden sp. n. to be a new species.  相似文献   

19.
The taxonomy, biology, and population status of flying foxes (Pteropus spp.) remain little investigated in the Caroline Islands, Micronesia, where multiple endemic taxa occur. Our study evaluated the taxonomic relationships between the flying foxes of the Mortlock Islands (a subgroup of the Carolines) and two closely related taxa from elsewhere in the region, and involved the first ever field study of the Mortlock population. Through a review of historical literature, the name Pteropus pelagicus Kittlitz, 1836 is resurrected to replace the prevailing but younger name Pteropus phaeocephalus Thomas, 1882 for the flying fox of the Mortlocks. On the basis of cranial and external morphological comparisons, Pteropus pelagicus is united taxonomically with Pteropus insularis “Hombron and Jacquinot, 1842” (with authority herein emended to Jacquinot and Pucheran 1853), and the two formerly monotypic species are now treated as subspecies — Pteropus pelagicus pelagicus in the Mortlocks, and Pteropus phaeocephalus insularis on the islands of Chuuk Lagoon and Namonuito Atoll. The closest relative of Pteropus pelagicus is Pteropus tokudae Tate, 1934, of Guam, which is best regarded as a distinct species. Pteropus pelagicus pelagicus is the only known resident bat in the Mortlock Islands, a chain of more than 100 atoll islands with a total land area of <12 km2. Based on field observations in 2004, we estimated a population size of 925–1,200 bats, most of which occurred on Satawan and Lukunor Atolls, the two largest and southernmost atolls in the chain. Bats were absent on Nama Island and possibly extirpated from Losap Atoll in the northern Mortlocks. Resident Mortlockese indicated bats were more common in the past, but that the population generally has remained stable in recent years. Most Pteropus phaeocephalus pelagicus roosted alone or in groups of 5–10 bats; a roost of 27 was the largest noted. Diet is comprised of at least eight plant species, with breadfruit (Artocarpus spp.) being a preferred food. Records of females with young (April, July) and pregnant females (July) suggest an extended breeding season. Pteropus pelagicus pelagicus appears most threatened by the prospect of sea level rise associated with global climate change, which has the potential to submerge or reduce the size of atolls in the Mortlocks. Occasional severe typhoons probably temporarily reduce populations on heavily damaged atolls, but hunting and ongoing habitat loss are not current problems for the subspecies.  相似文献   

20.
During a survey of entomopathogenic nematodes (EPNs) in the eastern Black Sea region of Turkey in 2009–2012, a steinernematid species was recorded and isolated using the Galleria-baiting method. The isolate was identified as Steinernema kraussei based on its morphological and molecular properties. The analysis of the ITS rDNA sequence placed the Turkish population of S. kraussei in the “feltiae-kraussei” group in the clade that contains different isolates of the species. This is the first record of S. kraussei from Turkey. The efficacy of S. kraussei was tested on Agrotis segetum (Lepidoptera: Noctuidea) larvae at different densities (100, 300, and 500 infective juveniles (IJs) g−1 dry sand ) in laboratory conditions at 25 °C. The highest mortality (98%) was obtained with 500 IJs g−1 dry sand within 7 d after inoculation. Our results indicate that the new isolate is a highly promising biological control agent against A. segetum, one of the most serious soil pests of agricultural area and fruits worldwide.  相似文献   

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