scholarly journals LARVAE OF NEOTROMBICULA TALMIENSIS (SCHLUGER, 1955) (ACARIFORMES, TROMBICULIDAE) AND THEIR FEATURES PARASITISM ON NATURAL HOSTS

2020 ◽  
Author(s):  
A.B. Shatrov ◽  
Keyword(s):  
Feeding Mode ◽  
Bank Voles ◽  
Pale Pink ◽  
Highly Effective ◽  
Natural Hosts ◽  
Siberian Chipmunk ◽  
Feeding Substrate ◽  
Species Specific ◽  
Host Tissues

Parasitengonina mites being a highly diverse and specialized phyletic lineage of the higher Acariformes, possess small and simply organized larvae. These larvae show a highly effective feeding mode of the proteinaceous feeding substrate consisting of the pre-oral digested host tissues. This capability is a result of the stylostome formation and allows larvae to overcome easily a high ontogenetic threshold between the larval organization and that of post-larval phases. Larvae of N. talmiensis evolve an identically organized pale-pink stylostome during feeding on both bank voles and Siberian chipmunk that confirm a hypothesis of the genus- or even species-specific stylostome organization.

scholarly journals Discovery of a Natural Microsporidian Pathogen with a Broad Tissue Tropism in Caenorhabditis elegans

2016 ◽  
Author(s):  
Robert J. Luallen ◽  
Aaron W. Reinke ◽  
Linda Tong ◽  
Michael R. Botts ◽  
Marie-Anne Félix ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Single Species ◽  
Microbial Pathogens ◽  
Specific Gene ◽  
Tissue Tropism ◽  
Microsporidian Parasite ◽  
C Elegans ◽  
Host Microbe Interactions ◽  
Species Specific ◽  
Host Tissues

AbstractMicrobial pathogens often establish infection within particular niches of their host for replication. Determining how infection occurs preferentially in specific host tissues is a key aspect of understanding host-microbe interactions. Here, we describe the discovery of a natural microsporidian parasite of the nematode Caenorhabditis elegans that has a unique tissue tropism compared to other parasites of C. elegans. We characterize the life cycle of this new species, Nematocida displodere, including pathogen entry, intracellular replication, and exit. N. displodere can invade multiple host tissues, including the epidermis, muscle, neurons, and intestine of C. elegans. Despite robust invasion of the intestine very little replication occurs there, with the majority of replication occurring in the muscle and epidermis. This feature distinguishes N. displodere from two closely related microsporidian pathogens, N. parisii and N. sp. 1, which exclusively invade and replicate in the intestine. Comparison of the N. displodere genome with N. parisii and N. sp. 1 reveals that N. displodere is the earliest diverging species of the Nematocida genus and devotes over 10% of its genome to a single species-specific gene family that may be mediating host interactions upon infection. Altogether, this system provides a convenient whole-animal model to investigate factors responsible for pathogen growth in different tissue niches.

scholarly journals PrPCGoverns Susceptibility to Prion Strains in Bank Vole, While Other Host Factors Modulate Strain Features

2016 ◽  
Vol 90 (23) ◽  
pp. 10660-10669 ◽  
Author(s):  
J. C. Espinosa ◽  
R. Nonno ◽  
M. Di Bari ◽  
P. Aguilar-Calvo ◽  
L. Pirisinu ◽  
...  
Keyword(s):  
Mouse Model ◽  
Transgenic Mice ◽  
Transgenic Mouse ◽  
Bank Vole ◽  
Differential Susceptibility ◽  
Transgenic Mouse Model ◽  
Host Factors ◽  
Bank Voles ◽  
Prion Strains ◽  
Species Specific

ABSTRACTBank vole is a rodent species that shows differential susceptibility to the experimental transmission of different prion strains. In this work, the transmission features of a panel of diverse prions with distinct origins were assayed both in bank vole expressing methionine at codon 109 (Bv109M) and in transgenic mice expressing physiological levels of bank vole PrPC(the BvPrP-Tg407 mouse line). This work is the first systematic comparison of the transmission features of a collection of prion isolates, representing a panel of diverse prion strains, in a transgenic-mouse model and in its natural counterpart. The results showed very similar transmission properties in both the natural species and the transgenic-mouse model, demonstrating the key role of the PrP amino acid sequence in prion transmission susceptibility. However, differences in the PrPSctypes propagated by Bv109M and BvPrP-Tg407 suggest that host factors other than PrPCmodulate prion strain features.IMPORTANCEThe differential susceptibility of bank voles to prion strains can be modeled in transgenic mice, suggesting that this selective susceptibility is controlled by the vole PrP sequence alone rather than by other species-specific factors. Differences in the phenotypes observed after prion transmissions in bank voles and in the transgenic mice suggest that host factors other than the PrPCsequence may affect the selection of the substrain replicating in the animal model.

scholarly journals Pseudorabies Virus EP0 Protein Counteracts an Interferon-Induced Antiviral State in a Species-Specific Manner

2006 ◽  
Vol 80 (21) ◽  
pp. 10871-10873 ◽  
Author(s):  
Alla Brukman ◽  
L. W. Enquist
Keyword(s):  
Pseudorabies Virus ◽  
Host Cells ◽  
Broad Host Range ◽  
Primary Cells ◽  
Varicella Zoster ◽  
Specific Manner ◽  
Natural Hosts ◽  
Species Specific ◽  
Simplex Virus

ABSTRACT Pseudorabies virus (PRV), an alphaherpesvirus related to herpes simplex virus type 1 and varicella-zoster virus, infects a broad host range of mammals. A striking characteristic of PRV infection is the different symptoms and outcomes of infection in natural and nonnatural hosts. Adult pigs, the natural hosts of PRV, survive infection with only mild respiratory symptoms, while nonnatural hosts, including rodents and cattle, invariably die after exhibiting neurological symptoms. Here, we show that the PRV EP0 protein is necessary to overcome an interferon-mediated antiviral response in primary cells from the natural host of PRV but is not necessary in nonnatural-host cells.

scholarly journals The genome of the plague-resistant great gerbil reveals species-specific duplication of an MHCII gene

2018 ◽  
Author(s):  
Pernille Nilsson ◽  
Monica H. Solbakken ◽  
Boris V. Schmid ◽  
Russell J. S. Orr ◽  
Ruichen Lv ◽  
...  
Keyword(s):  
Adaptive Immune Response ◽  
Gene Families ◽  
Comparative Genomic ◽  
Immune Gene ◽  
Gene Repertoire ◽  
Great Gerbil ◽  
Genomic Landscape ◽  
A Genome ◽  
Natural Hosts ◽  
Species Specific

AbstractThe great gerbil (Rhombomys opimus) is a social rodent living in permanent, complex burrow systems distributed throughout Central Asia, where it serves as the main host of several important vector-borne infectious diseases and is defined as a key reservoir species for plague (Yersinia pestis). Studies from the wild have shown that the great gerbil is largely resistant to plague but the genetic basis for resistance is yet to be determined. Here, we present a highly contiguous annotated genome assembly of great gerbil, covering over 96 % of the estimated 2.47 Gb genome. Comparative genomic analyses focusing on the immune gene repertoire, reveal shared gene losses within TLR gene families (i.e. TLR8, TLR10 and all members of TLR11-subfamily) for the Gerbillinae lineage, accompanied with signs of diversifying selection of TLR7 and TLR9. Most notably, we find a great gerbil-specific duplication of the MHCII DRB locus. In silico analyses suggest that the duplicated gene provides high peptide binding affinity for Yersiniae epitopes. The great gerbil genome provides new insights into the genomic landscape that confers immunological resistance towards plague. The high affinity for Yersinia epitopes could be key in our understanding of the high resistance in great gerbils, putatively conferring a faster initiation of the adaptive immune response leading to survival of the infection. Our study demonstrates the power of studying zoonosis in natural hosts through the generation of a genome resource for further comparative and experimental work on plague survival and evolution of host-pathogen interactions.

scholarly journals Prevalence of simian malaria parasites in macaques of Singapore

2021 ◽  
Vol 15 (1) ◽  
pp. e0009110
Author(s):  
Meizhi Irene Li ◽  
Diyar Mailepessov ◽  
Indra Vythilingam ◽  
Vernon Lee ◽  
Patrick Lam ◽  
...  
Keyword(s):  
Human Population ◽  
Malaria Parasite ◽  
Parasite Species ◽  
Plasmodium Knowlesi ◽  
Malaria Parasites ◽  
Simian Malaria ◽  
Specific Pcr ◽  
Natural Hosts ◽  
Multiple Species ◽  
Species Specific

Plasmodium knowlesi is a simian malaria parasite currently recognized as the fifth causative agent of human malaria. Recently, naturally acquired P. cynomolgi infection in humans was also detected in Southeast Asia. The main reservoir of both parasites is the long-tailed and pig-tailed macaques, which are indigenous in this region. Due to increased urbanization and changes in land use, there has been greater proximity and interaction between the long-tailed macaques and the general population in Singapore. As such, this study aims to determine the prevalence of simian malaria parasites in local macaques to assess the risk of zoonosis to the general human population. Screening for the presence of malaria parasites was conducted on blood samples from 660 peridomestic macaques collected between Jan 2008 and Mar 2017, and 379 wild macaques collected between Mar 2009 and Mar 2017, using a Pan-Plasmodium-genus specific PCR. Positive samples were then screened using a simian Plasmodium species-specific nested PCR assay to identify the species of parasites (P. knowlesi, P. coatneyi, P. fieldi, P. cynomolgi, and P. inui) present. All the peridomestic macaques sampled were tested negative for malaria, while 80.5% of the 379 wild macaques were infected. All five simian Plasmodium species were detected; P. cynomolgi being the most prevalent (71.5%), followed by P. knowlesi (47.5%), P. inui (42.0%), P. fieldi (32.5%), and P. coatneyi (28.5%). Co-infection with multiple species of Plasmodium parasites was also observed. The study revealed that Singapore’s wild long-tailed macaques are natural hosts of the five simian malaria parasite species, while no malaria was detected in all peridomestic macaques tested. Therefore, the risk of simian malaria transmission to the general human population is concluded to be low. However, this can be better demonstrated with the incrimination of the vectors of simian malaria parasites in Singapore.

Determination of axial polarity in the urodele limb regeneration blastema

Development ◽  
1982 ◽  
Vol 71 (1) ◽  
pp. 193-214
Author(s):  
David L. Stocum
Keyword(s):  
Limb Regeneration ◽  
Normal Number ◽  
Supernumerary Limbs ◽  
Graft Tissue ◽  
Species Specific ◽  
Host Tissues ◽  
Regeneration Blastema ◽  
Anterior Posterior ◽  
Thin Band

The state of determination of the anterior-posterior, dorsal-ventral and proximal-distal axes of the undifferentiated limb regeneration blastema was evaluated by heterografting and autografting experiments in which these axes were reversed with respect to the limb stump. Species-specific size differences in skeletal elements were used as markers to trace the origin of regenerate tissues in the heterografting experiments, and differences in the skeletal patterns of hindlimbs and forelimbs were used as markers in the autografting experiments. The resulting primary regenerates fell into two categories, those composed wholly or partly of donor tissues, and those composed entirely of host tissues. Regenerate structures formed from donor tissues always maintained the handedness of origin, while regenerates formed from host tissues always displayed host-side handedness. These results demonstrate that the axes of the blastema are determined from the start of regeneration, and that previous claims of axial lability in reversal experiments are based on an illusion created by resorption of graft tissue, accompanied by regeneration from the host. Reversal of the transverse axes resulted in the formation of supernumerary limbs. Analysis of heterograft cases in which the anterior-posterior axis was reversed showed that 50% of the supernumeraries were constructed partly of donor blastema tissue whose axial polarity was reversed with respect to the adjacent primary regenerate. The vast majority of the primary regenerates in these cases possessed the normal number of digits. It is thus likely that the reprogrammed donor blastema cells used to construct the supernumeraries are derived by division of a thin band of cells at the edge of the graft adjacent to the supernumerary.

scholarly journals Human Papillomavirus Type 31 Uses a Caveolin 1- and Dynamin 2-Mediated Entry Pathway for Infection of Human Keratinocytes

2007 ◽  
Vol 81 (18) ◽  
pp. 9922-9931 ◽  
Author(s):  
Jessica L. Smith ◽  
Samuel K. Campos ◽  
Michelle A. Ozbun
Keyword(s):  
Human Papillomavirus ◽  
Human Keratinocytes ◽  
Dominant Negative ◽  
Half Time ◽  
Caveolin 1 ◽  
Entry Pathway ◽  
Natural Hosts ◽  
Species Specific ◽  
Infectious Entry ◽  
Dynamin 2

ABSTRACT Papillomaviruses are species-specific and epitheliotropic DNA viruses that cause tumors in their natural hosts. Certain infections with genital human papillomavirus (HPV) types are causally related to cervical cancer development. Most papillomaviruses are thought to infect cells via a clathrin-dependent pathway, yet no studies have determined the entry route in permissive host epithelial cells. Employing fluorescently labeled and native virions, we tested the effects of dominant-negative and biochemical inhibitors of cellular endocytosis pathways. Infections of human keratinocytes, a natural host cell type for HPVs, were assessed visually and by infectious entry assays. We found that HPV type 31 (HPV31) entry and initiation of early infection events require both caveolin 1 and dynamin 2 and occur independently of clathrin-mediated endocytosis. Treatment with chlorpromazine and filipin had opposing effects on HPV31 and HPV16 infection. HPV31 entry was remarkably slow, with a half-time of ≈14 h, whereas the entry half-time of HPV16 was 4 h. Consistent with a caveola-mediated entry pathway for HPV31, the virions associated with detergent-resistant lipid rafts. During a 16-h microscopic tracking of HPV31 and HPV16 virions, no colocalization of the two viral types was observed. These data suggest that HPV31 and HPV16 virions use distinct routes for host epithelial cell entry.

Animal models of human cytomegalovirus congenital infection

2015 ◽  
Vol 36 (4) ◽  
pp. 196
Author(s):  
Helen Farrell
Keyword(s):  
Animal Models ◽  
Human Cytomegalovirus ◽  
Hcmv Infection ◽  
Phylogenetic Analyses ◽  
Congenital Infection ◽  
Host Responses ◽  
Laboratory Animals ◽  
Natural Hosts ◽  
Congenital Hcmv Infection ◽  
Species Specific

Human cytomegalovirus (HCMV) infection is highly species-specific, which means that it is unable to productively infect laboratory animals. Despite this caveat, studies of animal CMV counterparts in their natural hosts have revealed significant correlations with observed neuropathological effects of congenital HCMV infection and have improved our understanding of host responses to vaccination. The biological relatedness between human and animal CMVs has been confirmed by phylogenetic analyses; the conservation of ‘core' genes that are essential for virus replication as well as genes that contribute similar mechanisms for virus persistence in their respective host species. The common animal models of HCMV congenital infection include Rhesus CMV (RhCMV), guinea-pig CMV (GPCMV) and mouse CMV (MCMV). Whilst animal models of CMV do not fully recapitulate HCMV infection, they each offer specific advantages in understanding HCMV congenital/perinatal infection (summarised in Table 1).

scholarly journals The gastric properties of free-ranging harp (Pagophilus groenlandicus (Erxleben, 1777)) and hooded (Cystophora cristata (Erxleben, 1777)) seals

2004 ◽  
Vol 61 (2) ◽  
pp. 287-292 ◽  
Author(s):  
Jørgen S. Christiansen ◽  
Asbjørn Gildberg ◽  
Kjell T. Nilssen ◽  
Charlotta Lindblom ◽  
Tore Haug
Keyword(s):  
Trophic Relationships ◽  
Feeding Mode ◽  
Hooded Seal ◽  
Mean Values ◽  
Cystophora Cristata ◽  
Pagophilus Groenlandicus ◽  
Individual Variations ◽  
Species Specific ◽  
Stomach Weight ◽  
Free Ranging

Abstract The study of trophic relationships in seals is based primarily on prey remains recovered from the digestive tract or scats. Basic data on the gastric properties of seals are scarce and are considered to be important to interpret data from dietary studies of these animals. Hence, we examined the key properties of the gastric chyme post mortem (i.e. temperature, acidity, and the concentration of the proteolytic enzyme pepsin) in free-ranging harp (Pagophilus groenlandicus, n=40) and hooded (Cystophora cristata, n=41) seals. Seals displayed huge inter-individual variations in their gastric properties with ranges in temperature: 23.9–37.9°C, acidity: pH 1.16–7.34, and pepsin concentration: 11–1059 μg ml−1 chyme. The stomach weight and the mean values of gastric parameters revealed, however, significant species-specific differences. The stomach weight relative to body weight of hooded seal exceeded that of harp seal (t=13.77, d.f.=75, p<0.001). Furthermore, the gastric temperature and pepsin concentration were lower for harp (32.8°C and 75 μg ml−1) compared to that for hooded (35.3°C and 344 μg ml−1) seal. The reason for this disparity may be linked to the feeding mode and diet composition displayed by these seal species.

Host-induced variations in Haematoloechus buttensis (Trematoda: Haematoloechidae)

1980 ◽  
Vol 58 (3) ◽  
pp. 427-442 ◽  
Author(s):  
Murray J. Kennedy
Keyword(s):  
Life Cycle ◽  
Egg Size ◽  
Morphological Variations ◽  
As Species ◽  
Prior Use ◽  
Natural Hosts ◽  
Rana Pretiosa ◽  
Species Specific ◽  
Anterior Extent ◽  
Uninfected Host

The life cycle of Haematoloechus buttensis was maintained in the laboratory by using the usual natural hosts: Rana pretiosa, Physa nuttalli, and Ischnura perparva. Morphological variations in important taxonomic characters were studied and compared with those found when one of the usual hosts was replaced by a sympatric, but usually uninfected, host. In all, six species of Amphibia, three of Insecta, and three Mollusca were used.The effect of host size, sex, and ambient temperature was also studied using R. pretiosa as definitive host.The most reliable taxonomic characters were determined to be the sucker ratio, egg size of 21-day-old and older worms, position of the testes, and the anterior extent of the extracaecal uterine loops.The unreliability of other characters and their prior use as species-specific features suggests that many of the currently recognized species of Haematoloechus are not valid.

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