Susceptibility of common alder (Alnus glutinosa) seeds and seedlings to Phytophthora alni and other Phytophthora species

Energy Technology Data Exchange (ETDEWEB)

Haque, M. M.; Diez, J. J.

2012-11-01

Phytophthora alni is a highly destructive host specific pathogen to alders (Alnus spp.) spreading all over Europe. Recently this pathogen has been reported to cause diseases in common alder (Alnus glutinosa) in Spain. Seeds and seedlings of A. glutinosa were tested in vitro for their susceptibility to alder Phytophthora and other Phytophthora species. Isolates of P. alni ssp. alni, P. cinnamomi, P. citrophthora, P. nicotianae and P. palmivora were used in the experiments. Seeds and seedlings were inoculated with a zoospore suspension and uniform mycelial blocks of agar of the Phytophthora species. Susceptibility was calculated in terms of pathogen virulence on seed germination and seedling mortality 42 and 67 days after inoculation respectively. Seed germination and seedling mortality rates varied differently among the isolates used. Results implied that common alder and its seeds and seedlings are at risk to be infected by P. alni. In addition, other Phytophthora species are able to infect this kind of material showing their relative host non-specificity. This is one important finding concerning alder regeneration in infected areas, and the possibility of disease spread on this plant material. (Author) 42 refs.

Susceptibility of Staphylococcus species and subspecies to fleroxacin.

Science.gov (United States)

Bannerman, T L; Wadiak, D L; Kloos, W E

1991-01-01

Twenty-four Staphylococcus species or subspecies were examined for their susceptibilities to the fluoroquinolone fleroxacin (Ro 23-6240) by disk diffusion (5-micrograms disk) and by agar dilution for the determination of MICs. Resistant strains were further tested for their susceptibilities to oxacillin and the fluoroquinolone ciprofloxacin. Reference strains of the novobiocin-resistant species (Staphylococcus saprophyticus, Staphylococcus cohnii, Staphylococcus xylosus, Staphylococcus arlettae, and Staphylococcus gallinarum) had an intrinsic intermediate susceptibility (MIC, 4 micrograms/ml) to fleroxacin. Fleroxacin resistance was not observed in the reference strains of the novobiocin-susceptible species (MIC, 0.5 to 2.0 micrograms/ml). Clinical isolates of coagulase-negative species were generally less susceptible to fleroxacin than were reference strains. Seven percent of the Staphylococcus epidermidis clinical strains were resistant (MIC, greater than or equal to 8 micrograms/ml) to fleroxacin. Of these strains, 77% were resistant to oxacillin and 50% were resistant to ciprofloxacin. Thirty-four percent of the Staphylococcus haemolyticus clinical strains were resistant to fleroxacin, and 9% had intermediate susceptibility. Of the resistant strains, 95% were resistant to oxacillin and 77% were resistant to ciprofloxacin, while 23% had intermediate susceptibility to ciprofloxacin. Fleroxacin is an effective antimicrobial agent against most staphylococci. PMID:1759838

Cattle Tick Rhipicephalus microplus-Host Interface: A Review of Resistant and Susceptible Host Responses

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Ala E. Tabor

2017-12-01

Full Text Available Ticks are able to transmit tick-borne infectious agents to vertebrate hosts which cause major constraints to public and livestock health. The costs associated with mortality, relapse, treatments, and decreased production yields are economically significant. Ticks adapted to a hematophagous existence after the vertebrate hemostatic system evolved into a multi-layered defense system against foreign invasion (pathogens and ectoparasites, blood loss, and immune responses. Subsequently, ticks evolved by developing an ability to suppress the vertebrate host immune system with a devastating impact particularly for exotic and crossbred cattle. Host genetics defines the immune responsiveness against ticks and tick-borne pathogens. To gain an insight into the naturally acquired resistant and susceptible cattle breed against ticks, studies have been conducted comparing the incidence of tick infestation on bovine hosts from divergent genetic backgrounds. It is well-documented that purebred and crossbred Bos taurus indicus cattle are more resistant to ticks and tick-borne pathogens compared to purebred European Bos taurus taurus cattle. Genetic studies identifying Quantitative Trait Loci markers using microsatellites and SNPs have been inconsistent with very low percentages relating phenotypic variation with tick infestation. Several skin gene expression and immunological studies have been undertaken using different breeds, different samples (peripheral blood, skin with tick feeding, infestation protocols and geographic environments. Susceptible breeds were commonly found to be associated with the increased expression of toll like receptors, MHC Class II, calcium binding proteins, and complement factors with an increased presence of neutrophils in the skin following tick feeding. Resistant breeds had higher levels of T cells present in the skin prior to tick infestation and thus seem to respond to ticks more efficiently. The skin of resistant breeds also

Environment and host species shape the skin microbiome of captive neotropical bats

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Tromas, Nicolas; Shapiro, B. Jesse; Lapointe, François-Joseph

2016-01-01

Background A wide range of microorganisms inhabit animal skin. This microbial community (microbiome) plays an important role in host defense against pathogens and disease. Bats (Chiroptera: Mammalia) are an ecologically and evolutionarily diversified group with a relatively unexplored skin microbiome. The bat skin microbiome could play a role in disease resistance, for example, to white nose syndrome (WNS), an infection which has been devastating North American bat populations. However, fundamental knowledge of the bat skin microbiome is needed before understanding its role in health and disease resistance. Captive neotropical frugivorous bats Artibeus jamaicensis and Carollia perspicillataprovide a simple controlled system in which to characterize the factors shaping the bat microbiome. Here, we aimed to determine the relative importance of habitat and host species on the bat skin microbiome. Methods We performed high-throughput 16S rRNA gene sequencing of the skin microbiome of two different bat species living in captivity in two different habitats. In the first habitat, A. jamaicensis and C. perspicillata lived together, while the second habitat contained only A. jamaicensis. Results We found that both habitat and host species shape the composition and diversity of the skin microbiome, with habitat having the strongest influence. Cohabitating A. jamaicensis and C. perspicillata shared more similar skin microbiomes than members of the same species (A. jamaicensis) across two habitats. Discussion These results suggest that in captivity, the skin microbial community is homogenised by the shared environments and individual proximities of bats living together in the same habitat, at the expense of the innate host species factors. The predominant influence of habitat suggests that environmental microorganisms or pathogens might colonize bat skin. We also propose that bat populations could differ in pathogen susceptibility depending on their immediate environment and

Environment and host species shape the skin microbiome of captive neotropical bats

Directory of Open Access Journals (Sweden)

Virginie Lemieux-Labonté

2016-09-01

Full Text Available Background A wide range of microorganisms inhabit animal skin. This microbial community (microbiome plays an important role in host defense against pathogens and disease. Bats (Chiroptera: Mammalia are an ecologically and evolutionarily diversified group with a relatively unexplored skin microbiome. The bat skin microbiome could play a role in disease resistance, for example, to white nose syndrome (WNS, an infection which has been devastating North American bat populations. However, fundamental knowledge of the bat skin microbiome is needed before understanding its role in health and disease resistance. Captive neotropical frugivorous bats Artibeus jamaicensis and Carollia perspicillataprovide a simple controlled system in which to characterize the factors shaping the bat microbiome. Here, we aimed to determine the relative importance of habitat and host species on the bat skin microbiome. Methods We performed high-throughput 16S rRNA gene sequencing of the skin microbiome of two different bat species living in captivity in two different habitats. In the first habitat, A. jamaicensis and C. perspicillata lived together, while the second habitat contained only A. jamaicensis. Results We found that both habitat and host species shape the composition and diversity of the skin microbiome, with habitat having the strongest influence. Cohabitating A. jamaicensis and C. perspicillata shared more similar skin microbiomes than members of the same species (A. jamaicensis across two habitats. Discussion These results suggest that in captivity, the skin microbial community is homogenised by the shared environments and individual proximities of bats living together in the same habitat, at the expense of the innate host species factors. The predominant influence of habitat suggests that environmental microorganisms or pathogens might colonize bat skin. We also propose that bat populations could differ in pathogen susceptibility depending on their immediate

Host susceptibility hypothesis for shell disease in American lobsters.

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Tlusty, Michael F; Smolowitz, Roxanna M; Halvorson, Harlyn O; DeVito, Simone E

2007-12-01

Epizootic shell disease (ESD) in American lobsters Homarus americanus is the bacterial degradation of the carapace resulting in extensive irregular, deep erosions. The disease is having a major impact on the health and mortality of some American lobster populations, and its effects are being transferred to the economics of the fishery. While the onset and progression of ESD in American lobsters is undoubtedly multifactorial, there is little understanding of the direct causality of this disease. The host susceptibility hypothesis developed here states that although numerous environmental and pathological factors may vary around a lobster, it is eventually the lobster's internal state that is permissive to or shields it from the final onset of the diseased state. To support the host susceptibility hypothesis, we conceptualized a model of shell disease onset and severity to allow further research on shell disease to progress from a structured model. The model states that shell disease onset will occur when the net cuticle degradation (bacterial degradation, decrease of host immune response to bacteria, natural wear, and resorption) is greater than the net deposition (growth, maintenance, and inflammatory response) of the shell. Furthermore, lesion severity depends on the extent to which cuticle degradation exceeds deposition. This model is consistent with natural observations of shell disease in American lobster.

Colonization and infection with Trichosporon species in the immunosuppressed host.

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Haupt, H M; Merz, W G; Beschorner, W E; Vaughan, W P; Saral, R

1983-02-01

Trichosporon beigelii and Trichosporon capitatum have recently been recognized as systemic pathogens in the immunosuppressed host. We studied the incidence of colonization and systemic infection with these organisms in 353 highly immunocompromised patients over a 37-month period. Thirteen patients (3.7%) had positive surveillance cultures for Trichosporon species in stool, skin, or urine. Three of the 13 patients developed systemic infections after having positive surveillance cultures. In two of these three patients, urine cultures were positive near the time of systemic infection. The route of entry appeared to have been enteric in two patients and cutaneous in one patient. Both colonizing and infecting organisms showed in vitro susceptibility to amphotericin B and nystatin. This study suggests that positive surveillance cultures for Trichosporon species may correlate with systemic infection in the severely immunocompromised patient and that repeated positive urine cultures may indicate dissemination.

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

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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

SeqAPASS: Predicting chemical susceptibility to threatened/endangered species

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Conservation of a molecular target across species can be used as a line-of-evidence to predict the likelihood of chemical susceptibility. The web-based Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS; https://seqapass.epa.gov/seqapass/) application was devel...

Host specific glycans are correlated with susceptibility to infection by lagoviruses, but not with their virulence.

Science.gov (United States)

Lopes, Ana M; Breiman, Adrien; Lora, Mónica; Le Moullac-Vaidye, Béatrice; Galanina, Oxana; Nyström, Kristina; Marchandeau, Stephane; Le Gall-Reculé, Ghislaine; Strive, Tanja; Neimanis, Aleksija; Bovin, Nicolai V; Ruvoën-Clouet, Nathalie; Esteves, Pedro J; Abrantes, Joana; Le Pendu, Jacques

2017-11-29

The rabbit hemorrhagic disease virus (RHDV) and the European brown hare syndrome virus (EBHSV) are two lagoviruses from the family Caliciviridae that cause fatal diseases in two leporid genera, Oryctolagus and Lepus , respectively. In the last few years, several examples of host jumps of lagoviruses among leporids were recorded. In addition, a new pathogenic genotype of RHDV emerged and many non-pathogenic strains of lagoviruses have been described. The molecular mechanisms behind host shifts and the emergence of virulence are unknown. Since RHDV uses glycans of the histo-blood group antigen type as attachment factors to initiate infection, we studied if glycan specificities of the new pathogenic RHDV genotype, non-pathogenic lagoviruses and EBHSV potentially play a role in determining host range and virulence of lagoviruses. We observed binding to A, B or H antigens of the histo-blood group family for all strains known to primarily infect European rabbits ( Oryctolagus cuniculus ), that have recently been classified as GI strains. Yet, we could not explain the emergence of virulence since similar glycan specificities were found between several pathogenic and non-pathogenic strains. By contrast, EBHSV, recently classified as GII.1, bound to terminal β-linked N-acetylglucosamine residues of O-glycans. Expression of these attachment factors in the upper respiratory and digestive tracts in three lagomorph species ( Oryctolagus cuniculus, Lepus europaeus and Sylvilagus floridanus ) showed species-specific patterns regarding the susceptibility to infection by these viruses, indicating that species-specific glycan expression is likely a major contributor to lagoviruses host specificity and range. IMPORTANCE Lagoviruses constitute a genus of the Caliciviridae family, comprising highly pathogenic viruses, RHDV and EBHSV, which infect rabbits and hares, respectively. Recently, non-pathogenic strains were discovered and new pathogenic strains have emerged. In addition, host

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

Anaerobic bacteraemia revisited: species and susceptibilities.

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Ng, Lily S Y; Kwang, Lee Ling; Rao, Suma; Tan, Thean Yen

2015-01-01

This retrospective study was performed to evaluate the frequency of anaerobic bacteraemia over a 10-year period, and to provide updated antibiotic susceptibilities for the more clinically relevant anaerobes causing blood stream infection. Data were retrieved from the laboratory information system for the period 2003 to 2012. During this time, blood cultures were inoculated in Bactec™ Plus vials (BD, USA) and continuously monitored in the Bactec™ 9000 blood culture system (BD, USA). Anaerobic organisms were identified using commercial identification kits, predominantly API 20 A (bioMérieux, France) supplemented with Vitek ANC cards (bioMérieux, France) and AN-Ident discs (Oxoid, United Kingdom). A representative subset of isolates were retrieved from 2009 to 2011 and antimicrobial susceptibilities to penicillin, amoxicillin-clavulanate, clindamycin, imipenem, moxifloxacin, piperacillin-tazobactam and metronidazole were determined using the Etest method. Anaerobes comprised 4.1% of all positive blood culture with 727 obligate anaerobes recovered over the 10-year period, representing a positivity rate of 0.35%. The only significant change in anaerobe positivity rates occurred between 2003 and 2004, with an increase of 0.2%. The Bacteroides fragilis group (45%) were the predominant anaerobic pathogens, followed by Clostridium species (12%), Propioniobacterium species (11%) and Fusobacterium species (6%). The most active in vitro antibiotics were imipenem, piperacillin-tazobactam, amoxicillin-clavulanate and metronidazole, with susceptibilities of 95.0%, 93.3%, 90.8% and 90.8% respectively. Resistance was high to penicillin, clindamycin and moxifl oxacin. However, there were apparent differences for antibiotic susceptibilities between species. This study indicates that the anaerobes comprise a small but constant proportion of bloodstream isolates. Antibiotic resistance was high to some antibiotics, but metronidazole, the beta-lactam/beta-lactamase inhibitors and

Blood Groups in Infection and Host Susceptibility.

Science.gov (United States)

Cooling, Laura

2015-07-01

Blood group antigens represent polymorphic traits inherited among individuals and populations. At present, there are 34 recognized human blood groups and hundreds of individual blood group antigens and alleles. Differences in blood group antigen expression can increase or decrease host susceptibility to many infections. Blood groups can play a direct role in infection by serving as receptors and/or coreceptors for microorganisms, parasites, and viruses. In addition, many blood group antigens facilitate intracellular uptake, signal transduction, or adhesion through the organization of membrane microdomains. Several blood groups can modify the innate immune response to infection. Several distinct phenotypes associated with increased host resistance to malaria are overrepresented in populations living in areas where malaria is endemic, as a result of evolutionary pressures. Microorganisms can also stimulate antibodies against blood group antigens, including ABO, T, and Kell. Finally, there is a symbiotic relationship between blood group expression and maturation of the gastrointestinal microbiome. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Blood Groups in Infection and Host Susceptibility

Science.gov (United States)

2015-01-01

SUMMARY Blood group antigens represent polymorphic traits inherited among individuals and populations. At present, there are 34 recognized human blood groups and hundreds of individual blood group antigens and alleles. Differences in blood group antigen expression can increase or decrease host susceptibility to many infections. Blood groups can play a direct role in infection by serving as receptors and/or coreceptors for microorganisms, parasites, and viruses. In addition, many blood group antigens facilitate intracellular uptake, signal transduction, or adhesion through the organization of membrane microdomains. Several blood groups can modify the innate immune response to infection. Several distinct phenotypes associated with increased host resistance to malaria are overrepresented in populations living in areas where malaria is endemic, as a result of evolutionary pressures. Microorganisms can also stimulate antibodies against blood group antigens, including ABO, T, and Kell. Finally, there is a symbiotic relationship between blood group expression and maturation of the gastrointestinal microbiome. PMID:26085552

A model to estimate effects of SNPs on host susceptibility and infectivity for an endemic infectious disease.

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Biemans, Floor; de Jong, Mart C M; Bijma, Piter

2017-06-30

Infectious diseases in farm animals affect animal health, decrease animal welfare and can affect human health. Selection and breeding of host individuals with desirable traits regarding infectious diseases can help to fight disease transmission, which is affected by two types of (genetic) traits: host susceptibility and host infectivity. Quantitative genetic studies on infectious diseases generally connect an individual's disease status to its own genotype, and therefore capture genetic effects on susceptibility only. However, they usually ignore variation in exposure to infectious herd mates, which may limit the accuracy of estimates of genetic effects on susceptibility. Moreover, genetic effects on infectivity will exist as well. Thus, to design optimal breeding strategies, it is essential that genetic effects on infectivity are quantified. Given the potential importance of genetic effects on infectivity, we set out to develop a model to estimate the effect of single nucleotide polymorphisms (SNPs) on both host susceptibility and host infectivity. To evaluate the quality of the resulting SNP effect estimates, we simulated an endemic disease in 10 groups of 100 individuals, and recorded time-series data on individual disease status. We quantified bias and precision of the estimates for different sizes of SNP effects, and identified the optimum recording interval when the number of records is limited. We present a generalized linear mixed model to estimate the effect of SNPs on both host susceptibility and host infectivity. SNP effects were on average slightly underestimated, i.e. estimates were conservative. Estimates were less precise for infectivity than for susceptibility. Given our sample size, the power to estimate SNP effects for susceptibility was 100% for differences between genotypes of a factor 1.56 or more, and was higher than 60% for infectivity for differences between genotypes of a factor 4 or more. When disease status was recorded 11 times on each

Toxicogenetics: In Search of Host Susceptibility to Environmental Toxicants

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Gelareh eAlam

2014-09-01

Full Text Available Heavy metals, various pesticide and herbicides are implicated as risk factors for human health. Paraquat, maneb, and rotenone, carbamate and organophospherous insecticides are examples of toxicants for which acute and chronic exposure are associated with multiple neurological disorders including Parkinson’s disease (PD. Nevertheless, the role of pesticide exposure in neurodegenerative diseases is not clear-cut, as there are inconsistencies in both the epidemiological and preclinical research. The aim of this short review is to show that the inconsistencies are related to individual differences in susceptibility to the effects of neurotoxicants, individual differences that can be traced to the genetic constitution of the individuals and animals studies, i.e., host-based susceptibility.

Molecular systematics of pinniped hookworms (Nematoda: Uncinaria): species delimitation, host associations and host-induced morphometric variation.

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Nadler, Steven A; Lyons, Eugene T; Pagan, Christopher; Hyman, Derek; Lewis, Edwin E; Beckmen, Kimberlee; Bell, Cameron M; Castinel, Aurelie; Delong, Robert L; Duignan, Padraig J; Farinpour, Cher; Huntington, Kathy Burek; Kuiken, Thijs; Morgades, Diana; Naem, Soraya; Norman, Richard; Parker, Corwin; Ramos, Paul; Spraker, Terry R; Berón-Vera, Bárbara

2013-12-01

Hookworms of the genus Uncinaria have been widely reported from juvenile pinnipeds, however investigations of their systematics has been limited, with only two species described, Uncinaria lucasi from northern fur seals (Callorhinus ursinus) and Uncinaria hamiltoni from South American sea lions (Otaria flavescens). Hookworms were sampled from these hosts and seven additional species including Steller sea lions (Eumetopias jubatus), California sea lions (Zalophus californianus), South American fur seals (Arctocephalus australis), Australian fur seals (Arctocephalus pusillus), New Zealand sea lions (Phocarctos hookeri), southern elephant seals (Mirounga leonina), and the Mediterranean monk seal (Monachus monachus). One hundred and thirteen individual hookworms, including an outgroup species, were sequenced for four genes representing two loci (nuclear ribosomal DNA and mitochondrial DNA). Phylogenetic analyses of these sequences recovered seven independent evolutionary lineages or species, including the described species and five undescribed species. The molecular evidence shows that U. lucasi parasitises both C. ursinus and E. jubatus, whereas U. hamiltoni parasitises O. flavescens and A. australis. The five undescribed hookworm species were each associated with single host species (Z. californianus, A. pusillus, P. hookeri, M. leonina and M. monachus). For parasites of otarids, patterns of Uncinaria host-sharing and phylogenetic relationships had a strong biogeographic component with separate clades of parasites from northern versus southern hemisphere hosts. Comparison of phylogenies for these hookworms and their hosts suggests that the association of U. lucasi with northern fur seals results from a host-switch from Steller sea lions. Morphometric data for U. lucasi shows marked host-associated size differences for both sexes, with U. lucasi individuals from E. jubatus significantly larger. This result suggests that adult growth of U. lucasi is reduced within the

MicroRNA-Based Attenuation of Influenza Virus across Susceptible Hosts.

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Waring, Barbara M; Sjaastad, Louisa E; Fiege, Jessica K; Fay, Elizabeth J; Reyes, Ismarc; Moriarity, Branden; Langlois, Ryan A

2018-01-15

RNAs were used previously to attenuate influenza A viruses. We propose the development of a novel platform to produce live attenuated vaccines that are highly customizable, efficacious across a broad species range, and exhibit enhanced safety over traditional vaccination methods. This strategy exploits a microRNA that is expressed abundantly in influenza virus-susceptible hosts. By eliminating this ubiquitous microRNA from a cell line, targeted viruses that are attenuated across susceptible strains can be generated. This approach greatly increases the plasticity of the microRNA targeting approach and enhances vaccine safety. Copyright © 2018 American Society for Microbiology.

Host Phylogeny Determines Viral Persistence and Replication in Novel Hosts

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Longdon, Ben; Hadfield, Jarrod D.; Webster, Claire L.

2011-01-01

Pathogens switching to new hosts can result in the emergence of new infectious diseases, and determining which species are likely to be sources of such host shifts is essential to understanding disease threats to both humans and wildlife. However, the factors that determine whether a pathogen can infect a novel host are poorly understood. We have examined the ability of three host-specific RNA-viruses (Drosophila sigma viruses from the family Rhabdoviridae) to persist and replicate in 51 different species of Drosophilidae. Using a novel analytical approach we found that the host phylogeny could explain most of the variation in viral replication and persistence between different host species. This effect is partly driven by viruses reaching a higher titre in those novel hosts most closely related to the original host. However, there is also a strong effect of host phylogeny that is independent of the distance from the original host, with viral titres being similar in groups of related hosts. Most of this effect could be explained by variation in general susceptibility to all three sigma viruses, as there is a strong phylogenetic correlation in the titres of the three viruses. These results suggest that the source of new emerging diseases may often be predictable from the host phylogeny, but that the effect may be more complex than simply causing most host shifts to occur between closely related hosts. PMID:21966271

Fast Decline of Pythium zingiberum in Soil and Its Recolonization by Cultivating Susceptible Host Plants

OpenAIRE

ICHITANI, Takio; SHIMIZU, Tokiya

1984-01-01

This experiment demonstrates the fast decline of Pythium zingiberum in soil and its recolonization by cultivating mioga, susceptible host plant, and discusses growth and survival of the pathogen in the host rhizosphere in cultivated fields.

In silico site-directed mutagenesis informs species-specific predictions of chemical susceptibility derived from the Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool

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The Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool was developed to address needs for rapid, cost effective methods of species extrapolation of chemical susceptibility. Specifically, the SeqAPASS tool compares the primary sequence (Level 1), functiona...

Fish, fans and hydroids: host species of pygmy seahorses

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Bastian Reijnen

2011-06-01

Full Text Available An overview of the octocoral and hydrozoa host species of pygmy seahorses is provided, based on recently collected data for H. bargibanti, H. denise and H. pontohi and literature records. Seven new interspecific host-species associations are recognized, and an overview of the so far documented number of host species is given. Detailed re-examination of octocoral type material and a review of the taxonomic history are included, as a baseline for further studies. The host-specificity and colour morphs of pygmy seahorses are discussed, as well as the validity of (previous identifications and conservations issues.

antimicrobial susceptibility pattern of Salmonella species

African Journals Online (AJOL)

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GLOBAL JOURNAL OF COMMUNITY MEDICINE VOL. 2 NO. 1 & 2 2009: 5 - ... This study is a review of the contemporary antimicrobial susceptibility pattern of. Salmonella species. ... south-east Asia, parts of Latin America, the. Caribbean, and ...

Species associations among larval helminths in an amphipod intermediate host.

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Dezfuli, B S; Giari, L; Poulin, R

2000-10-01

Larval helminths that share the same intermediate host may or may not also share the same definitive hosts. If one or more of these helminth species can manipulate the phenotype of the intermediate host, there can be great advantages or severe costs for other helminths resulting from co-occurring with a manipulator, depending on whether they have the same definitive host or not. Among 2372 specimens of the amphipod Echinogammarus stammeri collected from the river Brenta, northern Italy, there was a positive association between two acanthocephalan species with the same fish definitive hosts, the relatively common Pomphorhynchus laevis and the much less prevalent Acanthocephalus clavula. The number of cystacanths of P. laevis per infected amphipod, which ranged from one to five, did not influence the likelihood that the amphipod would also host A. clavula. A third acanthocephalan species, Polymorphus minutus,which matures in birds, showed no association with either of the two other species. These results show that associations among helminth species in intermediate hosts are not random, and are instead the product of selection favouring certain pathways of transmission.

Antimicrobial susceptibility profile of Listeria species isolated from ...

African Journals Online (AJOL)

The antimicrobial susceptibility profile of L. monocytogenes and other Listeria species isolated from some ready-to-eat (RTE) foods sold in Kano metropolis, north-western Nigeria was carried out using disc-diffusion method. The results obtained showed that L. monocytogenes was moderately susceptible to all the ...

Host-parasite interactions in sympatric and allopatric populations of European bitterling.

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Francová, Kateřina; Ondračková, Markéta

2011-09-01

Susceptibility to parasite infection was examined in a field experiment for four populations of 0+ juvenile European bitterling (Rhodeus amarus): one sympatric to local parasite fauna, one allopatric, and two hybrid populations. Significantly higher parasite abundance was recorded in the allopatric bitterling population, suggesting a maladaptation of parasites to their sympatric host. Type of parasite life cycle played an important role in host-parasite interactions. While the abundance of allogenic species between populations was comparable, a significant difference was found in abundance of autogenic parasite species between fish populations, with the allopatric population more infected. These results correspond with a prediction of higher dispersion probability and higher gene flow among geographically distant populations of allogenic species as compared to autogenic species. Increased susceptibility to parasites that do not occur within the natural host's geographical distribution was found in the allopatric host, but only for autogenic species. A difference in infection susceptibility was detected among populations of early-hatched bitterling exposed to infection during a period of high parasite abundance and richness in the environment. Differences in parasite abundance and species diversity among populations diminished, however, with increasing time of exposure. No difference was found within late-hatched populations, probably due to a lower probability of infection in late-hatched cohorts.

Reservoir-host amplification of disease impact in an endangered amphibian.

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Scheele, Ben C; Hunter, David A; Brannelly, Laura A; Skerratt, Lee F; Driscoll, Don A

2017-06-01

Emerging wildlife pathogens are an increasing threat to biodiversity. One of the most serious wildlife diseases is chytridiomycosis, caused by the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which has been documented in over 500 amphibian species. Amphibians vary greatly in their susceptibility to Bd; some species tolerate infection, whereas others experience rapid mortality. Reservoir hosts-species that carry infection while maintaining high abundance but are rarely killed by disease-can increase extinction risk in highly susceptible, sympatric species. However, whether reservoir hosts amplify Bd in declining amphibian species has not been examined. We investigated the role of reservoir hosts in the decline of the threatened northern corroboree frog (Pseudophryne pengilleyi) in an amphibian community in southeastern Australia. In the laboratory, we characterized the response of a potential reservoir host, the (nondeclining) common eastern froglet (Crinia signifera), to Bd infection. In the field, we conducted frog abundance surveys and Bd sampling for both P. pengilleyi and C. signifera. We built multinomial logistic regression models to test whether Crinia signifera and environmental factors were associated with P. pengilleyi decline. C. signifera was a reservoir host for Bd. In the laboratory, many individuals maintained intense infections (>1000 zoospore equivalents) over 12 weeks without mortality, and 79% of individuals sampled in the wild also carried infections. The presence of C. signifera at a site was strongly associated with increased Bd prevalence in sympatric P. pengilleyi. Consistent with disease amplification by a reservoir host, P. pengilleyi declined at sites with high C. signifera abundance. Our results suggest that when reservoir hosts are present, population declines of susceptible species may continue long after the initial emergence of Bd, highlighting an urgent need to assess extinction risk in remnant populations of other declined

Differential host susceptibility to Batrachochytrium dendrobatidis, an emerging amphibian pathogen

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C.L. Searle; S.S. Gervasi; J. Hua; J.I. Hammond; R.A. Relyea; D.H. Olson; A.R. Blaustein

2011-01-01

The amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd) has received considerable attention due to its role in amphibian population declines worldwide. Although many amphibian species appear to be affected by Bd, there is little information on species-specific differences in susceptibility to this pathogen. We used a comparative...

Host phylogeny determines viral persistence and replication in novel hosts.

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Ben Longdon

2011-09-01

Full Text Available Pathogens switching to new hosts can result in the emergence of new infectious diseases, and determining which species are likely to be sources of such host shifts is essential to understanding disease threats to both humans and wildlife. However, the factors that determine whether a pathogen can infect a novel host are poorly understood. We have examined the ability of three host-specific RNA-viruses (Drosophila sigma viruses from the family Rhabdoviridae to persist and replicate in 51 different species of Drosophilidae. Using a novel analytical approach we found that the host phylogeny could explain most of the variation in viral replication and persistence between different host species. This effect is partly driven by viruses reaching a higher titre in those novel hosts most closely related to the original host. However, there is also a strong effect of host phylogeny that is independent of the distance from the original host, with viral titres being similar in groups of related hosts. Most of this effect could be explained by variation in general susceptibility to all three sigma viruses, as there is a strong phylogenetic correlation in the titres of the three viruses. These results suggest that the source of new emerging diseases may often be predictable from the host phylogeny, but that the effect may be more complex than simply causing most host shifts to occur between closely related hosts.

Host phenology and leaf effects on susceptibility of California bay laurel to Phytophthora ramorum

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Steven F. Johnston; Michael F. Cohen; Tamas Torok; Ross K. Meentemeyer; Nathan E. Rank

2016-01-01

Spread of the plant pathogen Phytophthora ramorum, causal agent of the forest disease sudden oak death, is driven by a few competent hosts that support spore production from foliar lesions. The relationship between traits of a principal foliar host, California bay laurel (Umbellularia californica), and susceptibility to

Cross-species infection trials reveal cryptic parasite varieties and a putative polymorphism shared among host species.

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Luijckx, Pepijn; Duneau, David; Andras, Jason P; Ebert, Dieter

2014-02-01

A parasite's host range can have important consequences for ecological and evolutionary processes but can be difficult to infer. Successful infection depends on the outcome of multiple steps and only some steps of the infection process may be critical in determining a parasites host range. To test this hypothesis, we investigated the host range of the bacterium Pasteuria ramosa, a Daphnia parasite, and determined the parasites success in different stages of the infection process. Multiple genotypes of Daphnia pulex, Daphnia longispina and Daphnia magna were tested with four Pasteuria genotypes using infection trials and an assay that determines the ability of the parasite to attach to the hosts esophagus. We find that attachment is not specific to host species but is specific to host genotype. This may suggest that alleles on the locus controlling attachment are shared among different host species that diverged 100 million year. However, in our trials, Pasteuria was never able to reproduce in nonnative host species, suggesting that Pasteuria infecting different host species are different varieties, each with a narrow host range. Our approach highlights the explanatory power of dissecting the steps of the infection process and resolves potentially conflicting reports on parasite host ranges. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Revisiting Trypanosoma rangeli Transmission Involving Susceptible and Non-Susceptible Hosts.

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Luciana de Lima Ferreira

Full Text Available Trypanosoma rangeli infects several triatomine and mammal species in South America. Its transmission is known to occur when a healthy insect feeds on an infected mammal or when an infected insect bites a healthy mammal. In the present study we evaluated the classic way of T. rangeli transmission started by the bite of a single infected triatomine, as well as alternative ways of circulation of this parasite among invertebrate hosts. The number of metacyclic trypomastigotes eliminated from salivary glands during a blood meal was quantified for unfed and recently fed nymphs. The quantification showed that ~50,000 parasites can be liberated during a single blood meal. The transmission of T. rangeli from mice to R. prolixus was evaluated using infections started through the bite of a single infected nymph. The mice that served as the blood source for single infected nymphs showed a high percentage of infection and efficiently transmitted the infection to new insects. Parasites were recovered by xenodiagnosis in insects fed on mice with infections that lasted approximately four months. Hemolymphagy and co-feeding were tested to evaluate insect-insect T. rangeli transmission. T. rangeli was not transmitted during hemolymphagy. However, insects that had co-fed on mice with infected conspecifics exhibited infection rates of approximately 80%. Surprisingly, 16% of the recipient nymphs became infected when pigeons were used as hosts. Our results show that T. rangeli is efficiently transmitted between the evaluated hosts. Not only are the insect-mouse-insect transmission rates high, but parasites can also be transmitted between insects while co-feeding on a living host. We show for the first time that birds can be part of the T. rangeli transmission cycle as we proved that insect-insect transmission is feasible during a co-feeding on these hosts.

Susceptibility of Japanese Cyprininae fish species to cyprinid herpesvirus 2 (CyHV-2).

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Ito, Takafumi; Maeno, Yukio

2014-03-14

Cyprinid herpesvirus 2 (CyHV-2) is known as the causative agent of herpesviral haematopoietic necrosis (HVHN) of goldfish (Carassius auratus). Recently, the virus has also been detected from Prussian carp (C. gibelio) and crucian carp (C. carassius) from European and Asian countries. To analyze the risk of spreading to new host species, the susceptibility of other fish species to the virus is essential. In this study experimental infections of indigenous Cyprininae species in Japan were performed by immersion in and intraperitoneal injection of a CyHV-2 isolate. Although Edonishiki, a variety of goldfish, immersed with the virus showed a cumulative mortality of 90%, no mortality was observed in ginbuna C. auratus langsdorfii, nagabuna C. auratus buergeri, nigorobuna C. auratus grandoculis and common carp Cyprinus carpio. Cumulative mortality was 100, 20 and 10% in intraperitoneally injected Edonishiki, ginbuna and nagabuna, respectively. Furthermore all Edonishiki immersed with the virus died. However, even after stimuli of sudden temperature changes, the immersed ginbuna and nagabuna did not die. Moreover no mortality was observed in co-reared Ranchu, another variety of goldfish, with immersed ginbuna and nagabuna although all three Ranchu co-reared with immersed Edonishiki died. CyHV-2 DNA was detected and the virus was re-isolated from all dead fish. Moreover CyHV-2 DNA was detected from some of the surviving Carassius spp. These results revealed that susceptibility of Japanese indigenous Cyprininae fish species to CyHV-2 is much lower than for goldfish. In addition, ability of replication of CyHV-2 might be different among Carassius fish species. Copyright © 2014 Elsevier B.V. All rights reserved.

The impact of Fusarium mycotoxins on human and animal host susceptibility to infectious diseases.

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Antonissen, Gunther; Martel, An; Pasmans, Frank; Ducatelle, Richard; Verbrugghe, Elin; Vandenbroucke, Virginie; Li, Shaoji; Haesebrouck, Freddy; Van Immerseel, Filip; Croubels, Siska

2014-01-28

Contamination of food and feed with mycotoxins is a worldwide problem. At present, acute mycotoxicosis caused by high doses is rare in humans and animals. Ingestion of low to moderate amounts of Fusarium mycotoxins is common and generally does not result in obvious intoxication. However, these low amounts may impair intestinal health, immune function and/or pathogen fitness, resulting in altered host pathogen interactions and thus a different outcome of infection. This review summarizes the current state of knowledge about the impact of Fusarium mycotoxin exposure on human and animal host susceptibility to infectious diseases. On the one hand, exposure to deoxynivalenol and other Fusarium mycotoxins generally exacerbates infections with parasites, bacteria and viruses across a wide range of animal host species. Well-known examples include coccidiosis in poultry, salmonellosis in pigs and mice, colibacillosis in pigs, necrotic enteritis in poultry, enteric septicemia of catfish, swine respiratory disease, aspergillosis in poultry and rabbits, reovirus infection in mice and Porcine Reproductive and Respiratory Syndrome Virus infection in pigs. However, on the other hand, T-2 toxin has been shown to markedly decrease the colonization capacity of Salmonella in the pig intestine. Although the impact of the exposure of humans to Fusarium toxins on infectious diseases is less well known, extrapolation from animal models suggests possible exacerbation of, for instance, colibacillosis and salmonellosis in humans, as well.

Relationships between host viremia and vector susceptibility for arboviruses.

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Lord, Cynthia C; Rutledge, C Roxanne; Tabachnick, Walter J

2006-05-01

Using a threshold model where a minimum level of host viremia is necessary to infect vectors affects our assessment of the relative importance of different host species in the transmission and spread of these pathogens. Other models may be more accurate descriptions of the relationship between host viremia and vector infection. Under the threshold model, the intensity and duration of the viremia above the threshold level is critical in determining the potential numbers of infected mosquitoes. A probabilistic model relating host viremia to the probability distribution of virions in the mosquito bloodmeal shows that the threshold model will underestimate the significance of hosts with low viremias. A probabilistic model that includes avian mortality shows that the maximum number of mosquitoes is infected by feeding on hosts whose viremia peaks just below the lethal level. The relationship between host viremia and vector infection is complex, and there is little experimental information to determine the most accurate model for different arthropod-vector-host systems. Until there is more information, the ability to distinguish the relative importance of different hosts in infecting vectors will remain problematic. Relying on assumptions with little support may result in erroneous conclusions about the importance of different hosts.

Commensal Bacteroides species induce colitis in host-genotype-specific fashion in a mouse model of inflammatory bowel disease

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Bloom, Seth M.; Bijanki, Vinieth N.; Nava, Gerardo M.; Sun, Lulu; Malvin, Nicole P.; Donermeyer, David L.; Dunne, W. Michael; Allen, Paul M.; Stappenbeck, Thaddeus S.

2011-01-01

SUMMARY The intestinal microbiota is important for induction of inflammatory bowel disease (IBD). IBD is associated with complex shifts in microbiota composition, but it is unclear whether specific bacterial subsets induce IBD and, if so, whether their proportions in the microbiota are altered during disease. Here we fulfilled Koch’s postulates in host-genotype-specific fashion using a mouse model of IBD with human-relevant disease-susceptibility mutations. From screening experiments we isolated common commensal Bacteroides species, introduced them into antibiotic-pretreated mice, and quantitatively re-isolated them in culture. The bacteria colonized IBD-susceptible and non-susceptible mice equivalently, but induced disease exclusively in susceptible animals. Conversely, commensal Enterobacteriaceae were >100-fold enriched during spontaneous disease but an Enterobacteriaceae isolate failed to induce disease in antibiotic-pretreated mice despite robust colonization. We thus demonstrate that IBD-associated microbiota alterations do not necessarily reflect underlying disease etiology. These findings establish important experimental criteria and a conceptual framework for understanding microbial contributions to IBD. PMID:21575910

Immune and biochemical responses in skin differ between bovine hosts genetically susceptible and resistant to the cattle tick Rhipicephalus microplus.

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Franzin, Alessandra Mara; Maruyama, Sandra Regina; Garcia, Gustavo Rocha; Oliveira, Rosane Pereira; Ribeiro, José Marcos Chaves; Bishop, Richard; Maia, Antônio Augusto Mendes; Moré, Daniela Dantas; Ferreira, Beatriz Rossetti; Santos, Isabel Kinney Ferreira de Miranda

2017-01-31

Ticks attach to and penetrate their hosts' skin and inactivate multiple components of host responses in order to acquire a blood meal. Infestation loads with the cattle tick, Rhipicephalus microplus, are heritable: some breeds carry high loads of reproductively successful ticks, whereas in others, few ticks feed and reproduce efficiently. In order to elucidate the mechanisms that result in the different outcomes of infestations with cattle ticks, we examined global gene expression and inflammation induced by tick bites in skins from one resistant and one susceptible breed of cattle that underwent primary infestations with larvae and nymphs of R. microplus. We also examined the expression profiles of genes encoding secreted tick proteins that mediate parasitism in larvae and nymphs feeding on these breeds. Functional analyses of differentially expressed genes in the skin suggest that allergic contact-like dermatitis develops with ensuing production of IL-6, CXCL-8 and CCL-2 and is sustained by HMGB1, ISG15 and PKR, leading to expression of pro-inflammatory chemokines and cytokines that recruit granulocytes and T lymphocytes. Importantly, this response is delayed in susceptible hosts. Histopathological analyses of infested skins showed inflammatory reactions surrounding tick cement cones that enable attachment in both breeds, but in genetically tick-resistant bovines they destabilized the cone. The transcription data provided insights into tick-mediated activation of basophils, which have previously been shown to be a key to host resistance in model systems. Skin from tick-susceptible bovines expressed more transcripts encoding enzymes that detoxify tissues. Interestingly, these enzymes also produce volatile odoriferous compounds and, accordingly, skin rubbings from tick-susceptible bovines attracted significantly more tick larvae than rubbings from resistant hosts. Moreover, transcripts encoding secreted modulatory molecules by the tick were significantly more

Phylogeny, life history, and ecology contribute to differences in amphibian susceptibility to ranaviruses.

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Hoverman, Jason T; Gray, Matthew J; Haislip, Nathan A; Miller, Debra L

2011-09-01

Research that identifies the potential host range of generalist pathogens as well as variation in host susceptibility is critical for understanding and predicting the dynamics of infectious diseases within ecological communities. Ranaviruses have been linked to amphibian die-off events worldwide with the greatest number of reported mortality events occurring in the United States. While reports of ranavirus-associated mortality events continue to accumulate, few data exist comparing the relative susceptibility of different species. Using a series of laboratory exposure experiments and comparative phylogenetics, we compared the susceptibilities of 19 amphibian species from two salamander families and five anurans families for two ranavirus isolates: frog virus 3 (FV3) and an FV3-like isolate from an American bullfrog culture facility. We discovered that ranaviruses were capable of infecting 17 of the 19 larval amphibian species tested with mortality ranging from 0 to 100%. Phylogenetic comparative methods demonstrated that species within the anuran family Ranidae were generally more susceptible to ranavirus infection compared to species from the other five families. We also found that susceptibility to infection was associated with species that breed in semi-permanent ponds, develop rapidly as larvae, and have limited range sizes. Collectively, these results suggest that phylogeny, life history characteristics, and habitat associations of amphibians have the potential to impact susceptibility to ranaviruses.

Host location by ichneumonid parasitoids is associated with nest dimensions of the host bee species.

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Flores-Prado, L; Niemeyer, H M

2012-08-01

Parasitoid fitness depends on the ability of females to locate a host. In some species of Ichneumonoidea, female parasitoids detect potential hosts through vibratory cues emanating from them or through vibrational sounding produced by antennal tapping on the substrate. In this study, we (1) describe host location behaviors in Grotea gayi Spinola (Hymenoptera: Ichneumonidae) and Labena sp. on nests of Manuelia postica Spinola (Hymenoptera: Apidae), (2) compare nest dimensions between parasitized and unparasitized nests, (3) correlate the length of M. postica nests with the number of immature individuals developing, and (4) establish the relative proportion of parasitized nests along the breeding period of M. postica. Based on our results, we propose that these parasitoids use vibrational sounding as a host location mechanism and that they are able to assess host nest dimensions and choose those which may provide them with a higher fitness. Finally, we discuss an ancestral host-parasitoid relationship between Manuelia and ichneumonid species.

Host switching in a generalist parasitoid: contrasting transient and transgenerational costs associated with novel and original host species.

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Jones, Thomas S; Bilton, Adam R; Mak, Lorraine; Sait, Steven M

2015-01-01

Parasitoids face challenges by switching between host species that influence survival and fitness, determine their role in structuring communities, influence species invasions, and affect their importance as biocontrol agents. In the generalist parasitoid, Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), we investigated the costs in encapsulation, survival, and body size on juveniles when adult parasitoids switched from their original host, Plodia interpunctella (Hübner) (Lepidotera, Pyralidae) to a novel host, Ephestia kuehniella (Zeller) (Lepidoptera, Pyralidae), over multiple generations. Switching had an initial survival cost for juvenile parasitoids in the novel host, but increased survival occurred within two generations. Conversely, mortality in the original host increased. Body size, a proxy for fecundity, also increased with the number of generations in the novel host species, reflecting adaptation or maternal effects due to the larger size of the novel host, and therefore greater resources available to the developing parasitoid. Switching to a novel host appears to have initial costs for a parasitoid, even when the novel host may be better quality, but the costs rapidly diminish. We predict that the net cost of switching to a novel host for parasitoids will be complex and will depend on the initial reduction in fitness from parasitizing a novel host versus local adaptations against parasitoids in the original host.

[The susceptibility of different animal species to synanthropic and natural populations of Trichinella].

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Artemenko, Iu G; Artemenko, L P

1997-01-01

Pigs have been found to be highly susceptible to the synanthropic (domestic) population of Trichinella [correction of Trachina] and weakly susceptible to the natural (native) one. Fur-bearing animals (polar foxes and foxes) are more susceptible to the natural population of Trichinella [correction of Trachina], but minks are equally sensible to the two variants of T. spiralis. In the host's body, synanthropic Trichinella [correction of Trachinas] form capsules of lemon-like, less frequently, oval shape, but the native population do round capsules. There is larval adaptation when Trichinella [correction of Trachina] larvae enter the nonspecific host's body after their prepassage through the organism of domestic carnivorous animals (cats, dogs). The pig is successfully infected with T. spiralis nativa via the cat or dog; the infection rate is approximately close to that observed during control infection of pigs with synanthropic Trichinella [correction of Trachina].

Do host species evolve a specific response to slave-making ants?

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Delattre Olivier

2012-12-01

Full Text Available Abstract Background Social parasitism is an important selective pressure for social insect species. It is particularly the case for the hosts of dulotic (so called slave-making ants, which pillage the brood of host colonies to increase the worker force of their own colony. Such raids can have an important impact on the fitness of the host nest. An arms race which can lead to geographic variation in host defenses is thus expected between hosts and parasites. In this study we tested whether the presence of a social parasite (the dulotic ant Myrmoxenus ravouxi within an ant community correlated with a specific behavioral defense strategy of local host or non-host populations of Temnothorax ants. Social recognition often leads to more or less pronounced agonistic interactions between non-nestmates ants. Here, we monitored agonistic behaviors to assess whether ants discriminate social parasites from other ants. It is now well-known that ants essentially rely on cuticular hydrocarbons to discriminate nestmates from aliens. If host species have evolved a specific recognition mechanism for their parasite, we hypothesize that the differences in behavioral responses would not be fully explained simply by quantitative dissimilarity in cuticular hydrocarbon profiles, but should also involve a qualitative response due to the detection of particular compounds. We scaled the behavioral results according to the quantitative chemical distance between host and parasite colonies to test this hypothesis. Results Cuticular hydrocarbon profiles were distinct between species, but host species did not show a clearly higher aggression rate towards the parasite than toward non-parasite intruders, unless the degree of response was scaled by the chemical distance between intruders and recipient colonies. By doing so, we show that workers of the host and of a non-host species in the parasitized site displayed more agonistic behaviors (bites and ejections towards parasite

Fish, fans and hydroids: host species of pygmy seahorses.

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Reijnen, Bastian T; van der Meij, Sancia E T; van Ofwegen, Leen P

2011-01-01

An overview of the octocoral and hydrozoan host species of pygmy seahorses is provided based on literature records and recently collected field data for Hippocampus bargibanti, Hippocampus denise and Hippocampus pontohi. Seven new associations are recognized and an overview of the so far documented host species is given. A detailed re-examination of octocoral type material and a review of the taxonomic history of the alcyonacean genera Annella (Subergorgiidae) and Muricella (Acanthogorgiidae) are included as baseline for future revisions. The host specificity and colour morphs of pygmy seahorses are discussed, as well as the reliability of (previous) identifications and conservation issues.

Host differentiation and variability of Orobanche crenata populations from legume species in Morocco as revealed by cross-infestation and molecular analysis.

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Ennami, Mounia; Briache, Fatima Zahra; Gaboun, Fatima; Abdelwahd, Rabha; Ghaouti, Lamiae; Belqadi, Loubna; Westwood, James; Mentag, Rachid

2017-08-01

Orobanche crenata represents a major biotic constraint to production of faba bean and lentil in Morocco. While this parasitic plant attacks both of these crops, the extent to which Orobanche biotypes specialise in parasitising specific crops is unknown. To address this question, we studied O. crenata that grew on different hosts and quantified their host specificity to faba bean and lentil. The virulence of O. crenata populations on each host was investigated through field trials, pot and Petri dishes assays. Genetic diversity of the parasite populations was also assessed through molecular analyses. The two legume species showed distinct patterns of specificity. Faba bean was more susceptible to both O. crenata populations, while the specificity for lentil by lentil-grown O. crenata was evident at the final stage of the parasite life cycle as shown by correspondence factorial analyses. Considerable internal variation (81%) within O. crenata populations parasitising both legume species was observed by molecular analyses, but significant divergence (19%; Ø = 0.189; P = 0.010) among the populations was detected. These results indicate that O. crenata can adapt to specific host species, which is important knowledge when developing integrated pest management practices for parasitic weed control. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Arabidopsis thaliana is a susceptible host plant for the holoparasite Cuscuta spec.

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Birschwilks, Mandy; Sauer, Norbert; Scheel, Dierk; Neumann, Stefanie

2007-10-01

Arabidopsis thaliana and Cuscuta spec. represent a compatible host-parasite combination. Cuscuta produces a haustorium that penetrates the host tissue. In early stages of development the searching hyphae on the tip of the haustorial cone are connected to the host tissue by interspecific plasmodesmata. Ten days after infection, translocation of the fluorescent dyes, Texas Red (TR) and 5,6-carboxyfluorescein (CF), demonstrates the existence of a continuous connection between xylem and phloem of the host and parasite. Cuscuta becomes the dominant sink in this host-parasite system. Transgenic Arabidopsis plants expressing genes encoding the green fluorescent protein (GFP; 27 kDa) or a GFP-ubiquitin fusion (36 kDa), respectively, under the companion cell (CC)-specific AtSUC2 promoter were used to monitor the transfer of these proteins from the host sieve elements to those of Cuscuta. Although GFP is transferred unimpedly to the parasite, the GFP-ubiquitin fusion could not be detected in Cuscuta. A translocation of the GFP-ubiquitin fusion protein was found to be restricted to the phloem of the host, although a functional symplastic pathway exists between the host and parasite, as demonstrated by the transport of CF. These results indicate a peripheral size exclusion limit (SEL) between 27 and 36 kDa for the symplastic connections between host and Cuscuta sieve elements. Forty-six accessions of A. thaliana covering the entire range of its genetic diversity, as well as Arabidopsis halleri, were found to be susceptible towards Cuscuta reflexa.

Host species and developmental stage, but not host social structure, affects bacterial community structure in socially polymorphic bees.

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McFrederick, Quinn S; Wcislo, William T; Hout, Michael C; Mueller, Ulrich G

2014-05-01

Social transmission and host developmental stage are thought to profoundly affect the structure of bacterial communities associated with honey bees and bumble bees, but these ideas have not been explored in other bee species. The halictid bees Megalopta centralis and M. genalis exhibit intrapopulation social polymorphism, which we exploit to test whether bacterial communities differ by host social structure, developmental stage, or host species. We collected social and solitary Megalopta nests and sampled bees and nest contents from all stages of host development. To survey these bacterial communities, we used 16S rRNA gene 454 pyrosequencing. We found no effect of social structure, but found differences by host species and developmental stage. Wolbachia prevalence differed between the two host species. Bacterial communities associated with different developmental stages appeared to be driven by environmentally acquired bacteria. A Lactobacillus kunkeei clade bacterium that is consistently associated with other bee species was dominant in pollen provisions and larval samples, but less abundant in mature larvae and pupae. Foraging adults appeared to often reacquire L. kunkeei clade bacteria, likely while foraging at flowers. Environmental transmission appears to be more important than social transmission for Megalopta bees at the cusp between social and solitary behavior. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Dual transcriptomics of virus-host interactions: comparing two Pacific oyster families presenting contrasted susceptibility to ostreid herpesvirus 1.

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Segarra, Amélie; Mauduit, Florian; Faury, Nicole; Trancart, Suzanne; Dégremont, Lionel; Tourbiez, Delphine; Haffner, Philippe; Barbosa-Solomieu, Valérie; Pépin, Jean-François; Travers, Marie-Agnès; Renault, Tristan

2014-07-09

Massive mortality outbreaks affecting Pacific oyster (Crassostrea gigas) spat in various countries have been associated with the detection of a herpesvirus called ostreid herpesvirus type 1 (OsHV-1). However, few studies have been performed to understand and follow viral gene expression, as it has been done in vertebrate herpesviruses. In this work, experimental infection trials of C. gigas spat with OsHV-1 were conducted in order to test the susceptibility of several bi-parental oyster families to this virus and to analyze host-pathogen interactions using in vivo transcriptomic approaches. The divergent response of these oyster families in terms of mortality confirmed that susceptibility to OsHV-1 infection has a significant genetic component. Two families with contrasted survival rates were selected. A total of 39 viral genes and five host genes were monitored by real-time PCR. Initial results provided information on (i) the virus cycle of OsHV-1 based on the kinetics of viral DNA replication and transcription and (ii) host defense mechanisms against the virus. In the two selected families, the detected amounts of viral DNA and RNA were significantly different. This result suggests that Pacific oysters are genetically diverse in terms of their susceptibility to OsHV-1 infection. This contrasted susceptibility was associated with dissimilar host gene expression profiles. Moreover, the present study showed a positive correlation between viral DNA amounts and the level of expression of selected oyster genes.

Molecules at the interface of Cryptococcus and the host that determine disease susceptibility.

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Wozniak, Karen L; Olszewski, Michal A; Wormley, Floyd L

2015-05-01

Cryptococcus neoformans and Cryptococcus gattii, the predominant etiological agents of cryptococcosis, are fungal pathogens that cause disease ranging from a mild pneumonia to life-threatening infections of the central nervous system (CNS). Resolution or exacerbation of Cryptococcus infection is determined following complex interactions of several host and pathogen derived factors. Alternatively, interactions between the host and pathogen may end in an impasse resulting in the establishment of a sub-clinical Cryptococcus infection. The current review addresses the delicate interaction between the host and Cryptococcus-derived molecules that determine resistance or susceptibility to infection. An emphasis will be placed on data highlighted at the recent 9th International Conference on Cryptococcus and Cryptococcosis (ICCC). Copyright © 2015. Published by Elsevier Inc.

Antimicrobial Susceptibility Patterns of Brachyspira Species Isolated from Swine Herds in the United States

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Mirajkar, Nandita S.; Davies, Peter R.

2016-01-01

Outbreaks of swine dysentery, caused by Brachyspira hyodysenteriae and the recently discovered “Brachyspira hampsonii,” have reoccurred in North American swine herds since the late 2000s. Additionally, multiple Brachyspira species have been increasingly isolated by North American diagnostic laboratories. In Europe, the reliance on antimicrobial therapy for control of swine dysentery has been followed by reports of antimicrobial resistance over time. The objectives of our study were to determine the antimicrobial susceptibility trends of four Brachyspira species originating from U.S. swine herds and to investigate their associations with the bacterial species, genotypes, and epidemiological origins of the isolates. We evaluated the susceptibility of B. hyodysenteriae, B. hampsonii, Brachyspira pilosicoli, and Brachyspira murdochii to tiamulin, valnemulin, doxycycline, lincomycin, and tylosin by broth microdilution and that to carbadox by agar dilution. In general, Brachyspira species showed high susceptibility to tiamulin, valnemulin, and carbadox, heterogeneous susceptibility to doxycycline, and low susceptibility to lincomycin and tylosin. A trend of decreasing antimicrobial susceptibility by species was observed (B. hampsonii > B. hyodysenteriae > B. murdochii > B. pilosicoli). In general, Brachyspira isolates from the United States were more susceptible to these antimicrobials than were isolates from other countries. Decreased antimicrobial susceptibility was associated with the genotype, stage of production, and production system from which the isolate originated, which highlights the roles of biosecurity and husbandry in disease prevention and control. Finally, this study also highlights the urgent need for Clinical and Laboratory Standards Institute-approved clinical breakpoints for Brachyspira species, to facilitate informed therapeutic and control strategies. PMID:27252458

Antimicrobial Susceptibility Patterns of Brachyspira Species Isolated from Swine Herds in the United States.

Science.gov (United States)

Mirajkar, Nandita S; Davies, Peter R; Gebhart, Connie J

2016-08-01

Outbreaks of swine dysentery, caused by Brachyspira hyodysenteriae and the recently discovered "Brachyspira hampsonii," have reoccurred in North American swine herds since the late 2000s. Additionally, multiple Brachyspira species have been increasingly isolated by North American diagnostic laboratories. In Europe, the reliance on antimicrobial therapy for control of swine dysentery has been followed by reports of antimicrobial resistance over time. The objectives of our study were to determine the antimicrobial susceptibility trends of four Brachyspira species originating from U.S. swine herds and to investigate their associations with the bacterial species, genotypes, and epidemiological origins of the isolates. We evaluated the susceptibility of B. hyodysenteriae, B. hampsonii, Brachyspira pilosicoli, and Brachyspira murdochii to tiamulin, valnemulin, doxycycline, lincomycin, and tylosin by broth microdilution and that to carbadox by agar dilution. In general, Brachyspira species showed high susceptibility to tiamulin, valnemulin, and carbadox, heterogeneous susceptibility to doxycycline, and low susceptibility to lincomycin and tylosin. A trend of decreasing antimicrobial susceptibility by species was observed (B. hampsonii > B. hyodysenteriae > B. murdochii > B. pilosicoli). In general, Brachyspira isolates from the United States were more susceptible to these antimicrobials than were isolates from other countries. Decreased antimicrobial susceptibility was associated with the genotype, stage of production, and production system from which the isolate originated, which highlights the roles of biosecurity and husbandry in disease prevention and control. Finally, this study also highlights the urgent need for Clinical and Laboratory Standards Institute-approved clinical breakpoints for Brachyspira species, to facilitate informed therapeutic and control strategies. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Commensal Bacteroides species induce colitis in host-genotype-specific fashion in a mouse model of inflammatory bowel disease.

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Bloom, Seth M; Bijanki, Vinieth N; Nava, Gerardo M; Sun, Lulu; Malvin, Nicole P; Donermeyer, David L; Dunne, W Michael; Allen, Paul M; Stappenbeck, Thaddeus S

2011-05-19

The intestinal microbiota is important for induction of inflammatory bowel disease (IBD). IBD is associated with complex shifts in microbiota composition, but it is unclear whether specific bacterial subsets induce IBD and, if so, whether their proportions in the microbiota are altered during disease. Here, we fulfilled Koch's postulates in host-genotype-specific fashion using a mouse model of IBD with human-relevant disease-susceptibility mutations. From screening experiments we isolated common commensal Bacteroides species, introduced them into antibiotic-pretreated mice, and quantitatively reisolated them in culture. The bacteria colonized IBD-susceptible and -nonsusceptible mice equivalently, but induced disease exclusively in susceptible animals. Conversely, commensal Enterobacteriaceae were >100-fold enriched during spontaneous disease, but an Enterobacteriaceae isolate failed to induce disease in antibiotic-pretreated mice despite robust colonization. We thus demonstrate that IBD-associated microbiota alterations do not necessarily reflect underlying disease etiology. These findings establish important experimental criteria and a conceptual framework for understanding microbial contributions to IBD. Copyright © 2011 Elsevier Inc. All rights reserved.

Identification of the same polyomavirus species in different African horseshoe bat species is indicative of short-range host-switching events.

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Carr, Michael; Gonzalez, Gabriel; Sasaki, Michihito; Dool, Serena E; Ito, Kimihito; Ishii, Akihiro; Hang'ombe, Bernard M; Mweene, Aaron S; Teeling, Emma C; Hall, William W; Orba, Yasuko; Sawa, Hirofumi

2017-10-06

Polyomaviruses (PyVs) are considered to be highly host-specific in different mammalian species, with no well-supported evidence for host-switching events. We examined the species diversity and host specificity of PyVs in horseshoe bats (Rhinolophus spp.), a broadly distributed and highly speciose mammalian genus. We annotated six PyV genomes, comprising four new PyV species, based on pairwise identity within the large T antigen (LTAg) coding region. Phylogenetic comparisons revealed two instances of highly related PyV species, one in each of the Alphapolyomavirus and Betapolyomavirus genera, present in different horseshoe bat host species (Rhinolophus blasii and R. simulator), suggestive of short-range host-switching events. The two pairs of Rhinolophus PyVs in different horseshoe bat host species were 99.9 and 88.8 % identical with each other over their respective LTAg coding sequences and thus constitute the same virus species. To corroborate the species identification of the bat hosts, we analysed mitochondrial cytb and a large nuclear intron dataset derived from six independent and neutrally evolving loci for bat taxa of interest. Bayesian estimates of the ages of the most recent common ancestors suggested that the near-identical and more distantly related PyV species diverged approximately 9.1E4 (5E3-2.8E5) and 9.9E6 (4E6-18E6) years before the present, respectively, in contrast to the divergence times of the bat host species: 12.4E6 (10.4E6-15.4E6). Our findings provide evidence that short-range host-switching of PyVs is possible in horseshoe bats, suggesting that PyV transmission between closely related mammalian species can occur.

Infection of non-host model plant species with the narrow-host-range Cacao swollen shoot virus.

Science.gov (United States)

Friscina, Arianna; Chiappetta, Laura; Jacquemond, Mireille; Tepfer, Mark

2017-02-01

Cacao swollen shoot virus (CSSV) is a major pathogen of cacao (Theobroma cacao) in Africa, and long-standing efforts to limit its spread by the culling of infected trees have had very limited success. CSSV is a particularly difficult virus to study, as it has a very narrow host range, limited to several tropical tree species. Furthermore, the virus is not mechanically transmissible, and its insect vector can only be used with difficulty. Thus, the only efficient means to infect cacao plants that have been experimentally described so far are by particle bombardment or the agroinoculation of cacao plants with an infectious clone. We have genetically transformed three non-host species with an infectious form of the CSSV genome: two experimental hosts widely used in plant virology (Nicotiana tabacum and N. benthamiana) and the model species Arabidopsis thaliana. In transformed plants of all three species, the CSSV genome was able to replicate, and, in tobacco, CSSV particles could be observed by immunosorbent electron microscopy, demonstrating that the complete virus cycle could be completed in a non-host plant. These results will greatly facilitate the preliminary testing of CSSV control strategies using plants that are easy to raise and to transform genetically. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Effects of Non-Susceptible Hosts on the Infection with Trypanosoma cruzi of the Vector Triatoma infestans: an Experimental Model

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Vázquez Diego P

1999-01-01

Full Text Available We tested experimentally the effects of the presence of non-susceptible hosts on the infection with Trypanosoma cruzi of the vector Triatoma infestans. The experiment consisted in two treatments: with chickens, including two chickens (non-susceptible hosts and two infected guinea pigs (susceptible hosts, and without chickens, including only two infected guinea pigs. The hosts were held unrestrained in individual metal cages inside a closed tulle chamber. A total of 200 uninfected T. infestans third instar nymphs were liberated in each replica, collected on day 14, and examined for infection and blood meal sources on day 32-36. The additional presence of chickens relative to infected guinea pigs: (a significantly modified the spatial distribution of bugs; (b increased significantly the likelihoods of having a detectable blood meal on any host and molting to the next instar; (c did not affect the bugs' probability of death by predation; and (d decreased significantly the overall percentage of T. infestans infected with T. cruzi. The bugs collected from inside or close to the guinea pigs' cages showed a higher infection rate (71-88% than those collected from the chickens' cages (22-32%. Mixed blood meals on chickens and guinea pigs were detected in 12-21% of bugs. Although the presence of chickens would decrease the overall percentage of infected bugs in short term experiments, the high rate of host change of T. infestans would make this difference fade out if longer exposure times had been provided.

No Effect of Host Species on Phenoloxidase Activity in a Mycophagous Beetle.

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Vincent Formica

Full Text Available Ecological immunology is an interdisciplinary field that helps elucidate interactions between the environment and immune response. The host species individuals experience have profound effects on immune response in many species of insects. However, this conclusion comes from studies of herbivorous insects even though species of mycophagous insects also inhabit many different host species. The goal of this study was to determine if fungal host species as well as individual, sex, body size, and host patch predict one aspect of immune function, phenoloxidase activity (PO. We sampled a metapopulation of Bolitotherus cornutus, a mycophagous beetle in southwestern Virginia. B. cornutus live on three species of fungus that differ in nutritional quality, social environment, and density. A filter paper phenoloxidase assay was used to quantify phenoloxidase activity. Overall, PO activity was significantly repeatable among individuals (0.57 in adult B. cornutus. While there was significant variance among individuals in PO activity, there were surprisingly no significant differences in PO activity among subpopulations, beetles living on different host species, or between the sexes; there was also no effect of body size. Our results suggest that other factors such as age, genotype, disease prevalence, or natal environment may be generating variance among individuals in PO activity.

The suitability of several aquatic snails as intermediate hosts for Angiostrongylus cantonensis.

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Yousif, F; Lämmler, G

1975-10-16

Sixteen species of aquatic snails of four families were tested by quantitative technique under standardized conditions for their suitability as intermediate hosts for Angiostrongylus cantonensis. These species were the planorbid snails Biomphalaria glabrata, Biomphalaria alexandrina, Planorbis planorbis, Planorbis intermixtus, Bulinus truncatus, Bulinus contortus, Bulinus africanus, Bulinus tropicus and Helisoma sp.; the lymnaeid snails Lymnaea natalensis, Lymnaea tomentosa, Lymnaea stagnalis, and Stagnicola elodes; the physid snail Physa acuta (an Egyptian and a German strain) and the ampullariid snails Marisa cornuarietis and Lanistes carinatus. All these snail species proved to be susceptible to infection with A. cantonensis, and first stage larvae reached the infective third stage in all of them. However, the rate and intensity of infection varied with different species. B. glabrata was the most susceptible snail species with a 100% infection rate and an average percentage recovery of third stage larvae of 26.1. This was followed by S. elodes and B. africanus, with a 100% infection rate and an average percentage recovery of third stage larvae of 15.6 and 14.6 respectively. The rest of snail species proved to be less susceptible. For comparative evaluation of the suitability of the various snail species as intermediate hosts of A. cantonensis a "Capacity Index" was determined. This index should provide a useful method for the evaluation of the suitability of various snails as intermediate hosts of nematode parasites under standardized conditions in the laboratory.

Antimicrobial susceptibility among clinical Nocardia species identified by multilocus sequence analysis.

Science.gov (United States)

McTaggart, Lisa R; Doucet, Jennifer; Witkowska, Maria; Richardson, Susan E

2015-01-01

Antimicrobial susceptibility patterns of 112 clinical isolates, 28 type strains, and 9 reference strains of Nocardia were determined using the Sensititre Rapmyco microdilution panel (Thermo Fisher, Inc.). Isolates were identified by highly discriminatory multilocus sequence analysis and were chosen to represent the diversity of species recovered from clinical specimens in Ontario, Canada. Susceptibility to the most commonly used drug, trimethoprim-sulfamethoxazole, was observed in 97% of isolates. Linezolid and amikacin were also highly effective; 100% and 99% of all isolates demonstrated a susceptible phenotype. For the remaining antimicrobials, resistance was species specific with isolates of Nocardia otitidiscaviarum, N. brasiliensis, N. abscessus complex, N. nova complex, N. transvalensis complex, N. farcinica, and N. cyriacigeorgica displaying the traditional characteristic drug pattern types. In addition, the antimicrobial susceptibility profiles of a variety of rarely encountered species isolated from clinical specimens are reported for the first time and were categorized into four additional drug pattern types. Finally, MICs for the control strains N. nova ATCC BAA-2227, N. asteroides ATCC 19247(T), and N. farcinica ATCC 23826 were robustly determined to demonstrate method reproducibility and suitability of the commercial Sensititre Rapmyco panel for antimicrobial susceptibility testing of Nocardia spp. isolated from clinical specimens. The reported values will facilitate quality control and standardization among laboratories. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Abrupt suspension of probiotics administration may increase host pathogen susceptibility by inducing gut dysbiosis

Science.gov (United States)

Liu, Zhi; Liu, Wenshu; Ran, Chao; Hu, Jun; Zhou, Zhigang

2016-01-01

In this study, we investigated the risk associated with suspension of probiotics administration in tilapia, an animal model that may mimic immune-compromised conditions in humans. Tilapias were fed for 14 days using a probiotics-supplemented diet, followed by a three-day suspension of probiotics treatment and a subsequent challenge by Aeromonas hydrophila. Unexpectedly, the suspension of a probiotic strain Lactobacillus plantarum JCM1149 significantly triggered susceptibility of the host to A. hydrophila. We further observed that suspension of JCM1149 resulted in host gut microbiota dysbiosis and the subsequent disorder in the intestinal metabolites (bile acids, amino acids, and glucose) and damage in the intestinal epithelium, giving rise to a condition similar to antibiotics-induced gut dysbiosis, which collectively impaired tilapia’s gut health and resistance to pathogenic challenges. Additionally, we determined that JCM1149 adhered relatively poorly to tilapia intestinal mucosa and was rapidly released from the gastrointestinal tract (GIT) after suspension, with the rapid loss of probiotic strain probably being the direct cause of gut dysbiosis. Finally, three other probiotic Lactobacillus strains with low intestinal mucosa binding activity showed similar rapid loss phenotype following administration suspension, and induced higher host susceptibility to infection, indicating that the risk is a generic phenomenon in Lactobacillus. PMID:26983596

Host plant use among closely related Anaea butterfly species (Lepidoptera, Nymphalidae, Charaxinae

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QUEIROZ J. M.

2002-01-01

Full Text Available There is a great number of Charaxinae (Lepidoptera: Nymphalidae species in the tropics whose larvae feed on several plant families. However the genus Anaea is almost always associated with Croton species (Euphorbiaceae. This work describes patterns of host plant use by immature and adult abundance on different vertical strata of sympatric Anaea species in a forest of Southeastern Brazil. Quantitative samples of leaves were taken in April/1999 and May/2000 to collect eggs and larvae of four Anaea species on C.alchorneicarpus, C. floribundus and C. salutaris in a semideciduous forest. Sampled leaves were divided into three classes of plant phenological stage: saplings, shrubs and trees. The results showed that the butterfly species are segregating in host plant use on two scales: host plant species and plant phenological stages. C. alchorneicarpus was used by only one Anaea species, whereas C. floribundus was used by three species and C. salutaris by four Anaea species. There was one Anaea species concentrated on sapling, another on sapling/shrub and two others on shrub/tree leaves. Adults of Anaea were more frequent at canopy traps but there were no differences among species caught in traps at different vertical positions. This work supplements early studies on host plant use among Charaxinae species and it describes how a guild of closely related butterfly species may be organized in a complex tropical habitat.

Molecular Diagnosis of Pathogenic Sporothrix Species

NARCIS (Netherlands)

Rodrigues, Anderson Messias; de Hoog, G Sybren; de Camargo, Zoilo Pires

2015-01-01

BACKGROUND: Sporotrichosis is a chronic (sub)cutaneous infection caused by thermodimorphic fungi in the order, Ophiostomatales. These fungi are characterized by major differences in routes of transmission, host predilections, species virulence, and susceptibilities to antifungals. Sporothrix species

Colonization, Pathogenicity, Host Susceptibility and Therapeutics for Staphylococcus aureus: What is the Clinical Relevance?1

Science.gov (United States)

Tong, Steven Y.C.; Chen, Luke F.; Fowler, Vance G.

2011-01-01

Staphylococcus aureus is a human commensal that can also cause a broad spectrum of clinical disease. Factors associated with clinical disease are myriad and dynamic and include pathogen virulence, antimicrobial resistance and host susceptibility. Additionally, infection control measures aimed at the environmental niches of S. aureus and therapeutic advances continue to impact upon the incidence and outcomes of staphylococcal infections. This review article focuses on the clinical relevance of advances in our understanding of staphylococcal colonization, virulence, host susceptibility and therapeutics. Over the past decade key developments have arisen. First, rates of nosocomial methicillin-resistant S. aureus (MRSA) infections have significantly declined in many countries. Second, we have made great strides in our understanding of the molecular pathogenesis of S. aureus in general and community-associated MRSA in particular. Third, host risk factors for invasive staphylococcal infections, such as advancing age, increasing numbers of invasive medical interventions, and a growing proportion of patients with healthcare contact, remain dynamic. Finally, several new antimicrobial agents active against MRSA have become available for clinical use. Humans and S. aureus co-exist and the dynamic interface between host, pathogen and our attempts to influence these interactions will continue to rapidly change. Although progress has been made in the past decade, we are likely to face further surprises such as the recent waves of community-associated MRSA. PMID:22160374

Bacteremia caused by Achromobacter species in an immunocompromised host.

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Kish, M A; Buggy, B P; Forbes, B A

1984-01-01

A case of bacteremia caused by Achromobacter species in an immunocompromised patient is described. The patient responded to antibiotic therapy. Detailed antibiotic susceptibility data are presented. PMID:6332118

Role of early experience in ant enslavement: a comparative analysis of a host and a non-host species

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Sermage Claire

2005-08-01

Full Text Available Abstract Background Ants use the odour of the colony to discriminate nestmates. In some species, this odour is learned during the first days following emergence, and thus early experience has a strong influence on nestmate discrimination. Slave-making ants are social parasites that capture brood of other ant species to increase the worker force of their colony. After emerging in the slave-maker nest, slave workers work as if they were in their own colony. We tested the hypothesis that early experience allows the deception of commonly enslaved species, while non-host species use a different mechanism, which does not involve learning. Results Pupae of a host species, Temnothorax unifasciatus, and a non-host species, T. parvulus, were allowed to emerge in the presence of workers of one of two slave-maker species, Chalepoxenus muellerianus or Myrmoxenus ravouxi. When T. unifasciatus was exposed to slave-makers for 10 days following emergence, they were more aggressive towards their own sisters and groomed the slave-maker more. T. parvulus gave a less clear result: while workers behaved more aggressively towards their sisters when exposed early to C. muellerianus workers, this was not the case when exposed early to M. ravouxi workers. Moreover, T. parvulus workers allogroomed conspecific nestmates less than T. unifasciatus. Allogrooming activity might be very important for the slave-makers because they are tended by their slaves. Conclusion Our findings show that early experience influences nestmate discrimination in the ant T. unifasciatus and can account for the successful enslavement of this species. However, the non-host species T. parvulus is less influenced by the early environment. This might help to explain why this species is never used by social parasites.

Codivergence and multiple host species use by fig wasp populations of the Ficus pollination mutualism

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McLeish Michael J

2012-01-01

Full Text Available Abstract Background The interaction between insects and plants takes myriad forms in the generation of spectacular diversity. In this association a species host range is fundamental and often measured using an estimate of phylogenetic concordance between species. Pollinating fig wasps display extreme host species specificity, but the intraspecific variation in empirical accounts of host affiliation has previously been underestimated. In this investigation, lineage delimitation and codiversification tests are used to generate and discuss hypotheses elucidating on pollinating fig wasp associations with Ficus. Results Statistical parsimony and AMOVA revealed deep divergences at the COI locus within several pollinating fig wasp species that persist on the same host Ficus species. Changes in branching patterns estimated using the generalized mixed Yule coalescent test indicated lineage duplication on the same Ficus species. Conversely, Elisabethiella and Alfonsiella fig wasp species are able to reproduce on multiple, but closely related host fig species. Tree reconciliation tests indicate significant codiversification as well as significant incongruence between fig wasp and Ficus phylogenies. Conclusions The findings demonstrate more relaxed pollinating fig wasp host specificity than previously appreciated. Evolutionarily conservative host associations have been tempered by horizontal transfer and lineage duplication among closely related Ficus species. Independent and asynchronistic diversification of pollinating fig wasps is best explained by a combination of both sympatric and allopatric models of speciation. Pollinator host preference constraints permit reproduction on closely related Ficus species, but uncertainty of the frequency and duration of these associations requires better resolution.

Taxonomy and antifungal susceptibility of clinically important Rasamsonia species

DEFF Research Database (Denmark)

Houbraken, J.; Giraud, S.; Meijer, M.

2013-01-01

In recent years, Geosmithia argillacea has been increasingly reported in humans and animals and can be considered an emerging pathogen. The taxonomy of Geosmithia was recently studied, and Geosmithia argillacea and related species were transferred to the new genus Rasamsonia. The diversity among...... reported clinical isolates from animal or human patients. Susceptibility tests showed that the antifungal susceptibility profiles of the four members of the R. argillacea complex are similar, and caspofungin showed significant activity in vitro, followed by amphotericin B and posaconazole. Voriconazole...

Evolutionary tools for phytosanitary risk analysis: phylogenetic signal as a predictor of host range of plant pests and pathogens.

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Gilbert, Gregory S; Magarey, Roger; Suiter, Karl; Webb, Campbell O

2012-12-01

Assessing risk from a novel pest or pathogen requires knowing which local plant species are susceptible. Empirical data on the local host range of novel pests are usually lacking, but we know that some pests are more likely to attack closely related plant species than species separated by greater evolutionary distance. We use the Global Pest and Disease Database, an internal database maintained by the United States Department of Agriculture Animal and Plant Health Inspection Service - Plant Protection and Quarantine Division (USDA APHIS-PPQ), to evaluate the strength of the phylogenetic signal in host range for nine major groups of plant pests and pathogens. Eight of nine groups showed significant phylogenetic signal in host range. Additionally, pests and pathogens with more known hosts attacked a phylogenetically broader range of hosts. This suggests that easily obtained data - the number of known hosts and the phylogenetic distance between known hosts and other species of interest - can be used to predict which plant species are likely to be susceptible to a particular pest. This can facilitate rapid assessment of risk from novel pests and pathogens when empirical host range data are not yet available and guide efficient collection of empirical data for risk evaluation.

Evolutionary tools for phytosanitary risk analysis: phylogenetic signal as a predictor of host range of plant pests and pathogens

Science.gov (United States)

Gilbert, Gregory S; Magarey, Roger; Suiter, Karl; Webb, Campbell O

2012-01-01

Assessing risk from a novel pest or pathogen requires knowing which local plant species are susceptible. Empirical data on the local host range of novel pests are usually lacking, but we know that some pests are more likely to attack closely related plant species than species separated by greater evolutionary distance. We use the Global Pest and Disease Database, an internal database maintained by the United States Department of Agriculture Animal and Plant Health Inspection Service – Plant Protection and Quarantine Division (USDA APHIS-PPQ), to evaluate the strength of the phylogenetic signal in host range for nine major groups of plant pests and pathogens. Eight of nine groups showed significant phylogenetic signal in host range. Additionally, pests and pathogens with more known hosts attacked a phylogenetically broader range of hosts. This suggests that easily obtained data – the number of known hosts and the phylogenetic distance between known hosts and other species of interest – can be used to predict which plant species are likely to be susceptible to a particular pest. This can facilitate rapid assessment of risk from novel pests and pathogens when empirical host range data are not yet available and guide efficient collection of empirical data for risk evaluation. PMID:23346231

Prevalence & susceptibility to fluconazole of Candida species causing vulvovaginitis.

Science.gov (United States)

Mohanty, Srujana; Xess, Immaculata; Hasan, Fahmi; Kapil, Arti; Mittal, Suneeta; Tolosa, Jorge E

2007-09-01

Vulvovaginal candidiasis is an important cause of morbidity in women of reproductive age. This study was carried out to determine the species prevalence and susceptibility pattern to fluconazole of yeasts isolated from the vagina of symptomatic women. This prospective study was conducted in a rural primary health care center of north India from May 2003 to April 2004 and included 601 married, sexually active women (18-49 yr) with the self reported symptoms of vaginal discharge and/or genital itching and/or genital burning. Specific aetiology of the genitourinary symptoms including candidal infection were determined. Specimens from the lateral wall of vagina were subjected to direct wet mount microscopy and fungal culture on Sabouraud's dextrose agar. Susceptibility testing to fluconazole was carried out using broth microdilution method. Yeasts were isolated in 111 (18.5%) women and these consisted of Candida glabrata (56, 50.4%), C. albicans (39, 35.1%), C. tropicalis (12, 10.8%), C. krusei (3, 2.7%) and C. parapsilosis (1, 0.9%). Susceptibility testing carried out on 30 representative isolates (15 C. glabrata, 10 C. albicans, 4 C. tropicalis and 1 C. parapsilosis) revealed that 21 isolates (70%) were susceptible (MIC, < or = 8 microg/ml) to fluconazole while 9 (30%) were susceptible-dose dependent (S-DD, MIC 16-32 microg/ml). Our findings suggest a low prevalence of fluconazole resistance in vaginal candida isolates in our population. However, a high prevalence of non-albicans candida species and increased dose-dependent resistance in these isolates necessitates vigilance since this may warrant a change in the optimal therapy of non-albicans candida vaginitis.

Chlamydia infection across host species boundaries promotes distinct sets of transcribed anti-apoptotic factors.

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Joshua eMessinger

2015-12-01

Full Text Available Chlamydiae, obligate intracellular bacteria, cause significant human and veterinary associated diseases. Having emerged an estimated 700-million years ago, these bacteria have twice adapted to humans as a host species, causing sexually transmitted infection (C. trachomatis and respiratory associated disease (C. pneumoniae. The principle mechanism of host cell defense against these intracellular bacteria is the induction of cell death via apoptosis. However, in the arms race of co-evolution, Chlamydiae have developed mechanisms to promote cell viability and inhibit cell death. Herein we examine the impact of Chlamydiae infection across multiple host species on transcription of anti-apoptotic genes. We found mostly distinct patterns of gene expression (Mcl1 and cIAPs elicited by each pathogen-host pair indicating Chlamydiae infection across host species boundaries does not induce a universally shared host response. Understanding species specific host-pathogen interactions is paramount to deciphering how potential pathogens become emerging diseases.

Climate driven range divergence among host species affects range-wide patterns of parasitism

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Richard E. Feldman

2017-01-01

Full Text Available Species interactions like parasitism influence the outcome of climate-driven shifts in species ranges. For some host species, parasitism can only occur in that part of its range that overlaps with a second host species. Thus, predicting future parasitism may depend on how the ranges of the two hosts change in relation to each other. In this study, we tested whether the climate driven species range shift of Odocoileus virginianus (white-tailed deer accounts for predicted changes in parasitism of two other species from the family Cervidae, Alces alces (moose and Rangifer tarandus (caribou, in North America. We used MaxEnt models to predict the recent (2000 and future (2050 ranges (probabilities of occurrence of the cervids and a parasite Parelaphostrongylus tenuis (brainworm taking into account range shifts of the parasite’s intermediate gastropod hosts. Our models predicted that range overlap between A. alces/R. tarandus and P. tenuis will decrease between 2000 and 2050, an outcome that reflects decreased overlap between A. alces/R. tarandus and O. virginianus and not the parasites, themselves. Geographically, our models predicted increasing potential occurrence of P. tenuis where A. alces/R. tarandus are likely to decline, but minimal spatial overlap where A. alces/R. tarandus are likely to increase. Thus, parasitism may exacerbate climate-mediated southern contraction of A. alces and R. tarandus ranges but will have limited influence on northward range expansion. Our results suggest that the spatial dynamics of one host species may be the driving force behind future rates of parasitism for another host species.

Toxoplasmosis and Polygenic Disease Susceptibility Genes: Extensive Toxoplasma gondii Host/Pathogen Interactome Enrichment in Nine Psychiatric or Neurological Disorders

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C. J. Carter

2013-01-01

Full Text Available Toxoplasma gondii is not only implicated in schizophrenia and related disorders, but also in Alzheimer's or Parkinson's disease, cancer, cardiac myopathies, and autoimmune disorders. During its life cycle, the pathogen interacts with ~3000 host genes or proteins. Susceptibility genes for multiple sclerosis, Alzheimer's disease, schizophrenia, bipolar disorder, depression, childhood obesity, Parkinson's disease, attention deficit hyperactivity disorder (multiple sclerosis, and autism (, but not anorexia or chronic fatigue are highly enriched in the human arm of this interactome and 18 (ADHD to 33% (MS of the susceptibility genes relate to it. The signalling pathways involved in the susceptibility gene/interactome overlaps are relatively specific and relevant to each disease suggesting a means whereby susceptibility genes could orient the attentions of a single pathogen towards disruption of the specific pathways that together contribute (positively or negatively to the endophenotypes of different diseases. Conditional protein knockdown, orchestrated by T. gondii proteins or antibodies binding to those of the host (pathogen derived autoimmunity and metabolite exchange, may contribute to this disruption. Susceptibility genes may thus be related to the causes and influencers of disease, rather than (and as well as to the disease itself.

Frequency and antimicrobial susceptibility of acinetobacter species isolated from blood samples of paediatric patients

International Nuclear Information System (INIS)

Javed, A.; Zafar, A.; Ejaz, H.; Zubair, M.

2012-01-01

Objective: Acinetobacter species is a major nosocomial pathogen causing serious infections in immuno-compromised and hospitalized patients. The aim of this study was to determine the frequency and antimicrobial susceptibility pattern of Acinetobacter species in blood samples of paediatric patients. Methodology: This cross sectional observational study was conducted during January to October, 2011 at The Children's Hospital and Institute of Child Health, Lahore. A total number of 12,032 blood samples were analysed during the study period. Acinetobacter species were Bauer disc diffusion method. Results: The blood cultures showed growth in 1,141 cultures out of which 46 (4.0%) were Acinetobacter species. The gender distribution of Acinetobacter species was 29 (63.0%) in males and 17 (37.0%) in females. A good antimicrobial susceptibility pattern of Acinetobacter species was seen with sulbactam-cefoperazone (93.0%), imepenem and meropenem (82.6% (30.4%) was poor. Conclusion: The results of the present study shows high rate of resistance of Acinetobacter species with cephalosporins in nosocomial infections. The sulbactam-cefoperazone, carbapenems and piperacillin-tazobactam showed effective antimicrobial susceptibility against Acinetobacter species. (author)

Degree of susceptibility of industrial gases of tree and shrub species

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Dobrovoljskii, I A

1952-01-01

The trees and shrubs of the iron smelting region of Krivoi Rog, in the Ukraine, were surveyed to determine susceptibility to air pollution damage. Most of the observations were made in parks and green belts in industrial areas. A classification of tree and shrub species is presented; they are separated into three classes according to their susceptibility to air pollutant injury.

Evaluating the non-rice host plant species of Sesamia inferens (Lepidoptera: Noctuidae) as natural refuges: resistance management of Bt rice.

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Liu, Zhuorong; Gao, Yulin; Luo, Ju; Lai, Fengxiang; Li, Yunhe; Fu, Qiang; Peng, Yufa

2011-06-01

Although rice (Oryza sativa L.) lines that express Bacillus thuringiensis (Bt) toxins have shown great potential for managing the major Lepidoptera pests of rice in southern China, including Sesamia inferens, their long-term use is dependent on managing resistance development to Bt toxins in pest populations. The maintenance of "natural" refuges, non-Bt expressing plants that are hosts for a target pest, has been proposed as a means to minimize the evolution of resistance to Bt toxins in transgenic plants. In the current study, field surveys and greenhouse experiments were conducted to identify host plants of S. inferens that could serve as "natural" refuges in rice growing areas of southern China. A field survey showed that 34 plant species in four families can be alternative host plants of S. inferens. Based on injury level under field conditions, rice (Oryza sativa L.); water oat (Zizania latifolia Griseb.); corn (Zea mays L.); tidalmarsh flatsedge (Cyperus serotinus Rottb.); and narrow-leaved cat-tail (Typha angustifolia Linn.) were identified as the primary host plant species of S. inferens. Greenhouse experiments further demonstrated that water oat, corn, and narrow-leaved cat-tail could support the survival and development of S. inferens. Interestingly, greenhouse experiments showed that S. inferens preferred to lay eggs on tidalmarsh flatsedge compared with the other three nonrice host species, although no pupae were found in the plants examined in field surveys. Few larvae were found to survive on tidalmarsh flatsedge in greenhouse bioassays, suggesting that tidalmarsh flatsedge could serve as a "dead-end" trap crop for S. inferens, but is not a candidate to serve as natural refuge to maintain susceptible S. inferens. Overall, these results suggest that water-oat, corn, and narrow-leaved cat-tail might serve as "natural refuge" for S. inferens in rice planting area of southern China when Bt rice varieties are planted.

Determination of antifungal susceptibility patterns among the clinical isolates of Candida species

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Kamiar Zomorodian

2011-01-01

Full Text Available Context: Candida species are opportunistic yeasts that cause infections ranging from simple dermatosis to potentially life-threatening fungemia. The emergence of resistance to antifungal drugs has been increased in the past two decades. Aim: the present study we determined to find out the susceptibility profiles of clinical isolates of Candida species against four antifungal drugs, including amphotericin B, ketoconazole, fluconazole and itraconazole. Materials and Methods: Antifungal susceptibility testing of the yeasts was done in accordance with the proposed guidelines for antifungal disk diffusion susceptibility testing of yeasts based on the CLSI document M44-A. Results: A total of 206 yeast isolates were assessed. Among the evaluated Candida species, the highest rates of resistance to ketoconazole were seen in Candida glabrata (16.6% and Candida albicans (3.2%. Susceptibility and intermediate response to fluconazole were seen in 96.6% and 3.4% of the Candida isolates, respectively. A total of 19 (9.2% yeast isolates showed petite phenomenon including 11 C. glabrata, 3 C. albicans, 2 Candida dubliniensis and one isolate of each Candida krusei and Candida parapsilosis. Conclusion: The high number of petite mutation in the isolated yeasts should be seriously considered since it may be one of the reasons of antifungal treatment failure.

Host heterogeneity influences the impact of a non-native disease invasion on populations of a foundation tree species

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Jules, Erik S.; Carroll, Allyson L.; Garcia, Andrea M.; Steenbock, Christopher M.; Kauffman, Matthew J.

2014-01-01

Invasive pathogens are becoming increasingly important in forested ecosystems, yet they are often difficult to study because of their rapid transmission. The rate and extent of pathogen spread are thought to be partially controlled by variation in host characteristics, such as when host size and location influence susceptibility. Few host-pathogen systems, however, have been used to test this prediction. We used Port Orford cedar (Chamaecyparis lawsoniana), a foundation tree species in riparian areas of California and Oregon (USA), and the invasive oomycete Phytophthora lateralis to assess pathogen impacts and the role of host characteristics on invasion. Across three streams that had been infected for 13–18 years by P. lateralis, we mapped 2241 trees and determined whether they had been infected using dendrochronology. The infection probability of trees was governed by host size (diameter at breast height [DBH]) and geomorphic position (e.g., active channel, stream bank, floodplain, etc.) similarly across streams. For instance, only 23% of trees <20 cm DBH were infected, while 69% of trees ≥20 cm DBH were infected. Presumably, because spores of P. lateralis are transported downstream in water, they are more likely to encounter well-developed root systems of larger trees. Also because of this water-transport of spores, differences in infection probability were found across the geomorphic positions: 59% of cedar in the active channel and the stream bank (combined) were infected, while 23% of trees found on higher geomorphic types were infected. Overall, 32% of cedar had been infected across the three streams. However, 63% of the total cedar basal area had been killed, because the greatest number of trees, and the largest trees, were found in the most susceptible positions. In the active channel and stream bank, 91% of the basal area was infected, while 46% was infected across higher geomorphic positions. The invasion of Port Orford cedar populations by

Virus Infection of Plants Alters Pollinator Preference: A Payback for Susceptible Hosts?

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Davey, Matthew P.; Bruce, Toby J. A.; Caulfield, John C.; Furzer, Oliver J.; Reed, Alison; Robinson, Sophie I.; Miller, Elizabeth; Davis, Christopher N.; Pickett, John A.; Whitney, Heather M.; Glover, Beverley J.; Carr, John P.

2016-01-01

Plant volatiles play important roles in attraction of certain pollinators and in host location by herbivorous insects. Virus infection induces changes in plant volatile emission profiles, and this can make plants more attractive to insect herbivores, such as aphids, that act as viral vectors. However, it is unknown if virus-induced alterations in volatile production affect plant-pollinator interactions. We found that volatiles emitted by cucumber mosaic virus (CMV)-infected tomato (Solanum lycopersicum) and Arabidopsis thaliana plants altered the foraging behaviour of bumblebees (Bombus terrestris). Virus-induced quantitative and qualitative changes in blends of volatile organic compounds emitted by tomato plants were identified by gas chromatography-coupled mass spectrometry. Experiments with a CMV mutant unable to express the 2b RNA silencing suppressor protein and with Arabidopsis silencing mutants implicate microRNAs in regulating emission of pollinator-perceivable volatiles. In tomato, CMV infection made plants emit volatiles attractive to bumblebees. Bumblebees pollinate tomato by ‘buzzing’ (sonicating) the flowers, which releases pollen and enhances self-fertilization and seed production as well as pollen export. Without buzz-pollination, CMV infection decreased seed yield, but when flowers of mock-inoculated and CMV-infected plants were buzz-pollinated, the increased seed yield for CMV-infected plants was similar to that for mock-inoculated plants. Increased pollinator preference can potentially increase plant reproductive success in two ways: i) as female parents, by increasing the probability that ovules are fertilized; ii) as male parents, by increasing pollen export. Mathematical modeling suggested that over a wide range of conditions in the wild, these increases to the number of offspring of infected susceptible plants resulting from increased pollinator preference could outweigh underlying strong selection pressures favoring pathogen resistance

Virus Infection of Plants Alters Pollinator Preference: A Payback for Susceptible Hosts?

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Simon C Groen

2016-08-01

Full Text Available Plant volatiles play important roles in attraction of certain pollinators and in host location by herbivorous insects. Virus infection induces changes in plant volatile emission profiles, and this can make plants more attractive to insect herbivores, such as aphids, that act as viral vectors. However, it is unknown if virus-induced alterations in volatile production affect plant-pollinator interactions. We found that volatiles emitted by cucumber mosaic virus (CMV-infected tomato (Solanum lycopersicum and Arabidopsis thaliana plants altered the foraging behaviour of bumblebees (Bombus terrestris. Virus-induced quantitative and qualitative changes in blends of volatile organic compounds emitted by tomato plants were identified by gas chromatography-coupled mass spectrometry. Experiments with a CMV mutant unable to express the 2b RNA silencing suppressor protein and with Arabidopsis silencing mutants implicate microRNAs in regulating emission of pollinator-perceivable volatiles. In tomato, CMV infection made plants emit volatiles attractive to bumblebees. Bumblebees pollinate tomato by 'buzzing' (sonicating the flowers, which releases pollen and enhances self-fertilization and seed production as well as pollen export. Without buzz-pollination, CMV infection decreased seed yield, but when flowers of mock-inoculated and CMV-infected plants were buzz-pollinated, the increased seed yield for CMV-infected plants was similar to that for mock-inoculated plants. Increased pollinator preference can potentially increase plant reproductive success in two ways: i as female parents, by increasing the probability that ovules are fertilized; ii as male parents, by increasing pollen export. Mathematical modeling suggested that over a wide range of conditions in the wild, these increases to the number of offspring of infected susceptible plants resulting from increased pollinator preference could outweigh underlying strong selection pressures favoring pathogen

Dinucleotide Composition in Animal RNA Viruses Is Shaped More by Virus Family than by Host Species.

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Di Giallonardo, Francesca; Schlub, Timothy E; Shi, Mang; Holmes, Edward C

2017-04-15

Viruses use the cellular machinery of their hosts for replication. It has therefore been proposed that the nucleotide and dinucleotide compositions of viruses should match those of their host species. If this is upheld, it may then be possible to use dinucleotide composition to predict the true host species of viruses sampled in metagenomic surveys. However, it is also clear that different taxonomic groups of viruses tend to have distinctive patterns of dinucleotide composition that may be independent of host species. To determine the relative strength of the effect of host versus virus family in shaping dinucleotide composition, we performed a comparative analysis of 20 RNA virus families from 15 host groupings, spanning two animal phyla and more than 900 virus species. In particular, we determined the odds ratios for the 16 possible dinucleotides and performed a discriminant analysis to evaluate the capability of virus dinucleotide composition to predict the correct virus family or host taxon from which it was isolated. Notably, while 81% of the data analyzed here were predicted to the correct virus family, only 62% of these data were predicted to their correct subphylum/class host and a mere 32% to their correct mammalian order. Similarly, dinucleotide composition has a weak predictive power for different hosts within individual virus families. We therefore conclude that dinucleotide composition is generally uniform within a virus family but less well reflects that of its host species. This has obvious implications for attempts to accurately predict host species from virus genome sequences alone. IMPORTANCE Determining the processes that shape virus genomes is central to understanding virus evolution and emergence. One question of particular importance is why nucleotide and dinucleotide frequencies differ so markedly between viruses. In particular, it is currently unclear whether host species or virus family has the biggest impact on dinucleotide frequencies and

Experimental Evaluation of Host Adaptation of Lactobacillus reuteri to Different Vertebrate Species.

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Duar, Rebbeca M; Frese, Steven A; Lin, Xiaoxi B; Fernando, Samodha C; Burkey, Thomas E; Tasseva, Guergana; Peterson, Daniel A; Blom, Jochen; Wenzel, Cory Q; Szymanski, Christine M; Walter, Jens

2017-06-15

The species Lactobacillus reuteri has diversified into host-specific lineages, implying a long-term association with different vertebrates. Strains from rodent lineages show specific adaptations to mice, but the processes underlying the evolution of L. reuteri in other hosts remain unknown. We administered three standardized inocula composed of strains from different host-confined lineages to mice, pigs, chickens, and humans. The ecological performance of each strain in the gastrointestinal tract of each host was determined by typing random colonies recovered from fecal samples collected over five consecutive days postadministration. Results revealed that rodent strains were predominant in mice, confirming previous findings of host adaptation. In chickens, poultry strains of the lineage VI (poultry VI) and human isolates from the same lineage (human VI) were recovered at the highest and second highest rates, respectively. Interestingly, human VI strains were virtually undetected in human feces. These findings, together with ancestral state reconstructions, indicate poultry VI and human VI strains share an evolutionary history with chickens. Genomic analysis revealed that poultry VI strains possess a large and variable accessory genome, whereas human VI strains display low genetic diversity and possess genes encoding antibiotic resistance and capsular polysaccharide synthesis, which might have allowed temporal colonization of humans. Experiments in pigs and humans did not provide evidence of host adaptation of L. reuteri to these hosts. Overall, our findings demonstrate host adaptation of L. reuteri to rodents and chickens, supporting a joint evolution of this bacterial species with several vertebrate hosts, although questions remain about its natural history in humans and pigs. IMPORTANCE Gut microbes are often hypothesized to have coevolved with their vertebrate hosts. However, the evidence is sparse and the evolutionary mechanisms have not been identified. We

Host range, host ecology, and distribution of more than 11800 fish parasite species

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Strona, Giovanni; Palomares, Maria Lourdes D.; Bailly, Nicholas; Galli, Paolo; Lafferty, Kevin D.

2013-01-01

Our data set includes 38 008 fish parasite records (for Acanthocephala, Cestoda, Monogenea, Nematoda, Trematoda) compiled from the scientific literature, Internet databases, and museum collections paired to the corresponding host ecological, biogeographical, and phylogenetic traits (maximum length, growth rate, life span, age at maturity, trophic level, habitat preference, geographical range size, taxonomy). The data focus on host features, because specific parasite traits are not consistently available across records. For this reason, the data set is intended as a flexible resource able to extend the principles of ecological niche modeling to the host–parasite system, providing researchers with the data to model parasite niches based on their distribution in host species and the associated host features. In this sense, the database offers a framework for testing general ecological, biogeographical, and phylogenetic hypotheses based on the identification of hosts as parasite habitat. Potential applications of the data set are, for example, the investigation of species–area relationships or the taxonomic distribution of host-specificity. The provided host–parasite list is that currently used by Fish Parasite Ecology Software Tool (FishPEST, http://purl.oclc.org/fishpest), which is a website that allows researchers to model several aspects of the relationships between fish parasites and their hosts. The database is intended for researchers who wish to have more freedom to analyze the database than currently possible with FishPEST. However, for readers who have not seen FishPEST, we recommend using this as a starting point for interacting with the database.

Mapping host-species abundance of three major exotic forest pests

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Randall S. Morin; Andrew M. Liebhold; Eugene R. Luzader; Andrew J. Lister; Kurt W. Gottschalk; Daniel B. Twardus

2005-01-01

Periodically over the last century, forests of the Eastern United States devastated by invasive pests. We used existing data to predict the geographical extent of future damage from beech bark disease (BBD), hemlock woolly adelgid (HWA), and gypsy moth. The distributions of host species of these alien pests were mapped in 1-km2 cells by interpolating host basal area/ha...

Miltefosine and antimonial drug susceptibility of Leishmania Viannia species and populations in regions of high transmission in Colombia.

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Olga Lucía Fernández

2014-05-01

Full Text Available Pentavalent antimonials have been the first line treatment for dermal leishmaniasis in Colombia for over 30 years. Miltefosine is administered as second line treatment since 2005. The susceptibility of circulating populations of Leishmania to these drugs is unknown despite clinical evidence supporting the emergence of resistance.In vitro susceptibility was determined for intracellular amastigotes of 245 clinical strains of the most prevalent Leishmania Viannia species in Colombia to miltefosine (HePC and/or meglumine antimoniate (Sb(V; 163, (80% were evaluated for both drugs. Additionally, susceptibility to Sb(V was examined in two cohorts of 85 L. V. panamensis strains isolated between 1980-1989 and 2000-2009 in the municipality of Tumaco. Susceptibility to each drug differed among strains of the same species and between species. Whereas 68% of L. V. braziliensis strains presented in vitro resistance to HePC, 69% were sensitive to Sb(V. Resistance to HePC and Sb(V occurred respectively, in 20% y 21% of L. panamensis strains. Only 3% of L. V. guyanensis were resistant to HePC, and none to Sb(V. Drug susceptibility differed between geographic regions and time periods. Subpopulations having disparate susceptibility to Sb(V were discerned among L. V. panamensis strains isolated during 1980-1990 in Tumaco where resistant strains belonged to zymodeme 2.3, and sensitive strains to zymodeme 2.2.Large scale evaluation of clinical strains of Leishmania Viannia species demonstrated species, population, geographic, and epidemiologic differences in susceptibility to meglumine antimoniate and miltefosine, and provided baseline information for monitoring susceptibility to these drugs. Sensitive and resistant clinical strains within each species, and zymodeme as a proxy marker of antimony susceptibility for L. V. panamensis, will be useful in deciphering factors involved in susceptibility and the distribution of sensitive and resistant populations.

Frequent cross-species transmission of parvoviruses among diverse carnivore hosts

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Allison, Andrew B.; Kohler, Dennis J.; Fox, Karen A.; Brown, Justin D.; Gerhold, Richard W.; Shearn-Bochsler, Valerie I.; Dubovi, Edward J.; Parrish, Colin R.; Holmes, Edward C.

2013-01-01

Although parvoviruses are commonly described in domestic carnivores, little is known about their biodiversity in nondomestic species. A phylogenetic analysis of VP2 gene sequences from puma, coyote, gray wolf, bobcat, raccoon, and striped skunk revealed two major groups related to either feline panleukopenia virus (“FPV-like”) or canine parvovirus (“CPV-like”). Cross-species transmission was commonplace, with multiple introductions into each host species but, with the exception of raccoons, relatively little evidence for onward transmission in nondomestic species.

Panamanian frog species host unique skin bacterial communities

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Lisa K. Belden

2015-10-01

Full Text Available Vertebrates, including amphibians, host diverse symbiotic microbes that contribute to host disease resistance. Globally, and especially in montane tropical systems, many amphibian species are threatened by a chytrid fungus, Batrachochytrium dendrobatidis (Bd, that causes a lethal skin disease. Bd therefore may be a strong selective agent on the diversity and function of the microbial communities inhabiting amphibian skin. In Panamá, amphibian population declines and the spread of Bd have been tracked. In 2012, we completed a field survey in Panamá to examine frog skin microbiota in the context of Bd infection. We focused on three frog species and collected two skin swabs per frog from a total of 136 frogs across four sites that varied from west to east in the time since Bd arrival. One swab was used to assess bacterial community structure using 16S rRNA amplicon sequencing and to determine Bd infection status, and one was used to assess metabolite diversity, as the bacterial production of anti-fungal metabolites is an important disease resistance function. The skin microbiota of the three Panamanian frog species differed in OTU (operational taxonomic unit, ~bacterial species community composition and metabolite profiles, although the pattern was less strong for the metabolites. Comparisons between frog skin bacterial communities from Panamá and the US suggest broad similarities at the phylum level, but key differences at lower taxonomic levels. In our field survey in Panamá, across all four sites, only 35 individuals (~26% were Bd infected. There was no clustering of OTUs or metabolite profiles based on Bd infection status and no clear pattern of west-east changes in OTUs or metabolite profiles across the four sites. Overall, our field survey data suggest that different bacterial communities might be producing broadly similar sets of metabolites across frog hosts and sites. Community structure and function may not be as tightly coupled in

Antifungal Susceptibilities of Candida Species Causing Vulvovaginitis and Epidemiology of Recurrent Cases

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Richter, Sandra S.; Galask, Rudolph P.; Messer, Shawn A.; Hollis, Richard J.; Diekema, Daniel J.; Pfaller, Michael A.

2005-01-01

There are limited data regarding the antifungal susceptibility of yeast causing vulvovaginal candidiasis, since cultures are rarely performed. Susceptibility testing was performed on vaginal yeast isolates collected from January 1998 to March 2001 from 429 patients with suspected vulvovaginal candidiasis. The charts of 84 patients with multiple positive cultures were reviewed. The 593 yeast isolates were Candida albicans (n = 420), Candida glabrata (n = 112), Candida parapsilosis (n = 30), Candida krusei (n = 12), Saccharomyces cerevisiae ( n = 9), Candida tropicalis (n = 8), Candida lusitaniae (n = 1), and Trichosporon sp. (n = 1). Multiple species suggesting mixed infection were isolated from 27 cultures. Resistance to fluconazole and flucytosine was observed infrequently (3.7% and 3.0%); 16.2% of isolates were resistant to itraconazole (MIC ≥ 1 μg/ml). The four imidazoles (econazole, clotrimazole, miconazole, and ketoconazole) were active: 94.3 to 98.5% were susceptible at ≤1 μg/ml. Among different species, elevated fluconazole MICs (≥16 μg/ml) were only observed in C. glabrata (15.2% resistant [R], 51.8% susceptible-dose dependent [S-DD]), C. parapsilosis (3.3% S-DD), S. cerevisiae (11.1% S-DD), and C. krusei (50% S-DD, 41.7% R, considered intrinsically fluconazole resistant). Resistance to itraconazole was observed among C. glabrata (74.1%), C. krusei (58.3%), S. cerevisiae (55.6%), and C. parapsilosis (3.4%). Among 84 patients with recurrent episodes, non-albicans species were more common (42% versus 20%). A ≥4-fold rise in fluconazole MIC was observed in only one patient with C. parapsilosis. These results support the use of azoles for empirical therapy of uncomplicated candidal vulvovaginitis. Recurrent episodes are more often caused by non-albicans species, for which azole agents are less likely to be effective. PMID:15872235

Impact of Nosema ceranae and Nosema apis on individual worker bees of the two host species (Apis cerana and Apis mellifera) and regulation of host immune response.

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Sinpoo, Chainarong; Paxton, Robert J; Disayathanoowat, Terd; Krongdang, Sasiprapa; Chantawannakul, Panuwan

Nosema apis and Nosema ceranae are obligate intracellular microsporidian parasites infecting midgut epithelial cells of host adult honey bees, originally Apis mellifera and Apis cerana respectively. Each microsporidia cross-infects the other host and both microsporidia nowadays have a worldwide distribution. In this study, cross-infection experiments using both N. apis and N. ceranae in both A. mellifera and A. cerana were carried out to compare pathogen proliferation and impact on hosts, including host immune response. Infection by N. ceranae led to higher spore loads than by N. apis in both host species, and there was greater proliferation of microsporidia in A. mellifera compared to A. cerana. Both N. apis and N. ceranae were pathogenic in both host Apis species. N. ceranae induced subtly, though not significantly, higher mortality than N. apis in both host species, yet survival of A. cerana was no different to that of A. mellifera in response to N. apis or N. ceranae. Infections of both host species with N. apis and N. ceranae caused significant up-regulation of AMP genes and cellular mediated immune genes but did not greatly alter apoptosis-related gene expression. In this study, A. cerana enlisted a higher immune response and displayed lower loads of N. apis and N. ceranae spores than A. mellifera, suggesting it may be better able to defend itself against microsporidia infection. We caution against over-interpretation of our results, though, because differences between host and parasite species in survival were insignificant and because size differences between microsporidia species and between host Apis species may alternatively explain the differential proliferation of N. ceranae in A. mellifera. Copyright © 2017 Elsevier Ltd. All rights reserved.

Host social organization and mating system shape parasite transmission opportunities in three European bat species.

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van Schaik, J; Kerth, G

2017-02-01

For non-mobile parasites living on social hosts, infection dynamics are strongly influenced by host life history and social system. We explore the impact of host social systems on parasite population dynamics by comparing the infection intensity and transmission opportunities of three mite species of the genus Spinturnix across their three European bat hosts (Myotis daubentonii, Myotis myotis, Myotis nattereri) during the bats' autumn mating season. Mites mainly reproduce in host maternity colonies in summer, but as these colonies are closed, opportunities for inter-colony transmission are limited to host interactions during the autumn mating season. The three investigated hosts differ considerably in their social system, most notably in maternity colony size, mating system, and degree of male summer aggregation. We observed marked differences in parasite infection during the autumn mating period between the species, closely mirroring the predictions made based on the social systems of the hosts. Increased host aggregation sizes in summer yielded higher overall parasite prevalence and intensity, both in male and female hosts. Moreover, parasite levels in male hosts differentially increased throughout the autumn mating season in concordance with the degree of contact with female hosts afforded by the different mating systems of the hosts. Critically, the observed host-specific differences have important consequences for parasite population structure and will thus affect the coevolutionary dynamics between the interacting species. Therefore, in order to accurately characterize host-parasite dynamics in hosts with complex social systems, a holistic approach that investigates parasite infection and transmission across all periods is warranted.

Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

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Panngom, Kamonporn; Lee, Sang Hark; Park, Dae Hoon; Sim, Geon Bo; Kim, Yong Hee; Uhm, Han Sup; Park, Gyungsoon; Choi, Eun Ha

2014-01-01

Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

Estimating host genetic effects on susceptibility and infectivity to infectious diseases and their contribution to response to selection

NARCIS (Netherlands)

Anche, M.T.

2016-01-01

Mahlet Teka Anche. (2016). Estimating host genetic effects on susceptibility and infectivity to infectious diseases and their contribution to response to selection. PhD thesis, Wageningen University, the Netherlands

Genetic approaches aiming to reduce the prevalence of an infection in a

Biology and occurrence of Inga Busk species (Lepidoptera: Oecophoridae) on Cerrado host plants.

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Diniz, Ivone R; Bernardes, Carolina; Rodovalho, Sheila; Morais, Helena C

2007-01-01

We sampled Inga Busk species caterpillars weekly in the cerrado on 15 plants of Diospyros burchellii Hern. (Ebenaceae) from January 2002 to December 2003, on 30 plants of Caryocar brasiliense (Caryocaraceae) from July 2003 to June 2004, and since 1991 on several other plant species. In total we found 15 species of Inga on cerrado host plants. Nine species were very rare, with only one to five adults reared. The other six species occurred throughout the year, with higher abundance during the dry season, from May to July, coinciding with overall peaks of caterpillar abundance in the cerrado. Caterpillars of the genus Inga build shelters by tying and lining two mature or old leaves with silk and frass, where they rest and develop (a common habit found in Oecophorinae). The final instar builds a special envelope inside the leaf shelter, where it will complete the larval stage and pupate. The species are very difficult to distinguish in the immature stages. External features were useful in identifying only four species: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). These four species are polyphagous and have wide geographical distributions. In this paper we provide information on the natural history and host plants of six Inga species common on cerrado host plants, for which there are no reports in the literature.

Morphological variation and host range of two Ganoderma species from Papua New Guinea.

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Pilotti, Carmel A; Sanderson, Frank R; Aitken, Elizabeth A B; Armstrong, Wendy

2004-08-01

Two species of Ganoderma belonging to different subgenera which cause disease on oil palms in PNG are identified by basidiome morphology and the morphology of their basidiospores. The names G. boninense and G. tornatum have been applied. Significant pleiomorphy was observed in basidiome characters amongst the specimens examined. This variation in most instances did not correlate well with host or host status. Spore morphology appeared uniform within a species and spore indices varied only slightly. G. tornatum was found to have a broad host range whereas G. boninense appears to be restricted to palms in Papua New Guinea.

Antimicrobial susceptibility pattern of Acinetobacter species isolated from infected wounds at a tertiary care hospital

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Rosić Ivana

2013-01-01

Full Text Available Bacteria of the genus Acinetobacter, especially species Acinetobacter baumanii, is one of the most important causes of infection in immunocompromised patients in hospital. The aim of this study was to determine susceptibility of Acinetobacter species isolated from swabs of inflamed wounds to antibiotics. The study was conducted in several departments of the Clinical Centre 'Kragujevac' through retrospective analysis of 220 Acinetobacter species isolates from surgical wounds in 2011. The isolates of Acinetobaster species were mostly sensitive to ampicillin-sulbactam, colistin and tigecycline in all hospital departments that were surveyed. Only minority of the isolated Acinetobacter species were susceptible to cotrimoxazole, amikacin, imipenem and/or meropenem. Antibiotics with the highest in vitro efficacy against Acinetobacter species were ampicillinsulbactam, colistin and tigecycline. Highly resistant Acinetobacter species were more frequently isolated from patients in Intensive Care Unit.

Role of NETs in the difference in host susceptibility to Toxoplasma gondii between sheep and cattle.

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Yildiz, Kader; Gokpinar, Sami; Gazyagci, Aycan Nuriye; Babur, Cahit; Sursal, Neslihan; Azkur, Ahmet Kursat

2017-07-01

The main aim of this study was to compare extracellular traps (NETs) formation by polymorphonuclear neutrophils (PMNs) of cattle and sheep when exposed to T. gondii tachyzoites in vitro. The effects of parasite concentrations and different incubation periods on NETs development in cattle and sheep PMNs were studied. The effect of NET structures on host cell invasion by tachyzoites was also studied. This is the first report of NETs development by sheep and cattle PMNs against T. gondii in vitro. T. gondii-induced extracellular DNA production from PMNs was dependent on tachyzoite concentrations and incubation time in both sheep and cattle. Many nuclear and cytoplasmic changes were observed in sheep and cattle PMNs after exposure to T. gondii tachyzoites. The typical appearance of NETs, with MPO, NE and histone (H3) attached to extracellular DNA, was observed. Tachyzoites were entrapped within this structure. Myeloperoxidase (MPO) activity was higher in the cattle PMN-tachyzoite co-cultures than sheep. NETs structures released from sheep PMNs caused mechanical immobilisation of T. gondii tachyzoites, however, NET structures released from cattle PMNs may be lethal to tachyzoites. Bovine MPO may have a lethal effect on T. gondii tachyzoites in vitro during a 3h incubation. Besides other mechanisms that effect on host susceptibility to T. gondii in sheep and cattle, extracellular traps formation as a part of immunological reactions may be play a role in host susceptibility to T. gondii. Copyright © 2017 Elsevier B.V. All rights reserved.

Diversity and Geographical Distribution of Flavobacterium psychrophilum Isolates and Their Phages: Patterns of Susceptibility to Phage Infection and Phage Host Range

DEFF Research Database (Denmark)

Castillo, Daniel; Christiansen, Rói Hammershaimb; Espejo, Romilio

2014-01-01

in disease control requires detailed knowledge about the diversity and dynamics of host susceptibility to phage infection. For this reason, we examined the genetic diversity of 49 F. psychrophilum strains isolated in three different areas (Chile, Denmark, and USA) through direct genome restriction enzyme...... analysis (DGREA) and their susceptibility to 33 bacteriophages isolated in Chile and Denmark, thus covering large geographical (>12,000 km) and temporal (>60 years) scales of isolation. An additional 40 phage-resistant isolates obtained from culture experiments after exposure to specific phages were...... examined for changes in phage susceptibility against the 33 phages. The F. psychrophilum and phage populations isolated from Chile and Denmark clustered into geographically distinct groups with respect to DGREA profile and host range, respectively. However, cross infection between Chilean phage isolates...

Patterns of host adaptation in fly infecting Entomophthora species

DEFF Research Database (Denmark)

de Fine Licht, Henrik Hjarvard; Jensen, Annette Bruun; Eilenberg, Jørgen

Insect pathogenic fungi (IPF) differ widely in their capability to infect different hosts. Some are generalists and will, given a sufficient number of infectious spores are present, infect almost any species of insect (e.g. Hypocrealean Metarhizium and Beauveria). Members of a different main IPF ...

Genetic diversity within the morphological species Giardia intestinalis and its relationship to host origin.

Science.gov (United States)

Monis, Paul T; Andrews, Ross H; Mayrhofer, Graham; Ey, Peter L

2003-05-01

A genetic analysis of Giardia intestinalis, a parasitic protozoan species that is ubiquitous in mammals worldwide, was undertaken using organisms derived from a variety of mammalian hosts in different geographical locations. The test panel of 53 Giardia isolates comprised 48 samples of G. intestinalis, including representatives of all known genetic subgroups, plus an isolate of G. ardeae and four isolates of G. muris. The isolates were compared by allozymic analysis of electrophoretic data obtained for 21 cytosolic enzymes, representing 23 gene loci. Neighbour Joining analysis of the allelic profiles supported the monophyly of G. intestinalis but showed that the species encompasses a rich population substructure. Seven major clusters were evident within G. intestinalis, corresponding to lineages designated previously as genetic assemblages A-G. Some genotypes, e.g. those defining assemblage A, are found in divergent host species and may be zoonotic. However other genotypes, e.g. those defining assemblages C-G, appear to be confined to particular hosts or host groups. The findings reinforce other evidence that G. intestinalis, which was defined on the basis of morphological criteria only, is a species complex.

Host Plant Species Differentiation in a Polyphagous Moth: Olfaction is Enough.

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Conchou, Lucie; Anderson, Peter; Birgersson, Göran

2017-08-01

Polyphagous herbivorous insects need to discriminate suitable from unsuitable host plants in complex plant communities. While studies on the olfactory system of monophagous herbivores have revealed close adaptations to their host plant's characteristic volatiles, such adaptive fine-tuning is not possible when a large diversity of plants is suitable. Instead, the available literature on polyphagous herbivore preferences suggests a higher level of plasticity, and a bias towards previously experienced plant species. It is therefore necessary to take into account the diversity of plant odors that polyphagous herbivores encounter in the wild in order to unravel the olfactory basis of their host plant choice behaviour. In this study we show that a polyphagous moth, Spodoptera littoralis, has the sensory ability to distinguish five host plant species using olfaction alone, this being a prerequisite to the ability to make a choice. We have used gas chromatography mass spectrometry (GC-MS) and gas chromatography electroantennographic detection (GC-EAD) in order to describe host plant odor profiles as perceived by S. littoralis. We find that each plant emits specific combinations and proportions of GC-EAD active volatiles, leading to statistically distinct profiles. In addition, at least four of these plants show GC-EAD active compound proportions that are conserved across individual plants, a characteristic that enables insects to act upon previous olfactory experiences during host plant choice. By identifying the volatiles involved in olfactory differentiation of alternative host plants by Spodoptera littoralis, we set the groundwork for deeper investigations of how olfactory perceptions translate into behaviour in polyphagous herbivores.

Species boundaries and host range of tortoise mites (Uropodoidea phoretic on bark beetles (Scolytinae, using morphometric and molecular markers.

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Wayne Knee

Full Text Available Understanding the ecology and evolutionary history of symbionts and their hosts requires accurate taxonomic knowledge, including clear species boundaries and phylogenies. Tortoise mites (Mesostigmata: Uropodoidea are among the most diverse arthropod associates of bark beetles (Curculionidae: Scolytinae, but their taxonomy and host associations are largely unstudied. We tested the hypotheses that (1 morphologically defined species are supported by molecular data, and that (2 bark beetle uropodoids with a broad host range comprise cryptic species. To do so, we assessed the species boundaries of uropodoid mites collected from 51 host species, across 11 countries and 103 sites, using morphometric data as well as partial cytochrome oxidase I (COI and nuclear large subunit ribosomal DNA (28S. Overall, morphologically defined species were confirmed by molecular datasets, with a few exceptions. Twenty-nine of the 36 uropodoid species (Trichouropoda, Nenteria and Uroobovella collected in this study had narrow host ranges, while seven species had putative broad host ranges. In all but one species, U. orri, our data supported the existence of these host generalists, which contrasts with the typical finding that widespread generalists are actually complexes of cryptic specialists.

Cross-Species Virus-Host Protein-Protein Interactions Inhibiting Innate Immunity

Science.gov (United States)

2016-07-01

diseases are a regular occurrence globally (Figure 1). The Zika virus is the latest example gaining widespread attention. Many of the (re-)emerging...for establishing infection and/or modulating pathogenesis (Figures 2 and 3). 3 Figure 2. Schematic of several virus -host protein interactions within...8725 John J. Kingman Road, MS 6201 Fort Belvoir, VA 22060-6201 T E C H N IC A L R E P O R T DTRA-TR-16-79 Cross-species virus -host

Parasite transmission in social interacting hosts: Monogenean epidemics in guppies

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Johnson, Mirelle B.; Lafferty, Kevin D.; van Oosterhout, Cock; Cable, Joanne

2011-01-01

Background Infection incidence increases with the average number of contacts between susceptible and infected individuals. Contact rates are normally assumed to increase linearly with host density. However, social species seek out each other at low density and saturate their contact rates at high densities. Although predicting epidemic behaviour requires knowing how contact rates scale with host density, few empirical studies have investigated the effect of host density. Also, most theory assumes each host has an equal probability of transmitting parasites, even though individual parasite load and infection duration can vary. To our knowledge, the relative importance of characteristics of the primary infected host vs. the susceptible population has never been tested experimentally. Methodology/Principal Findings Here, we examine epidemics using a common ectoparasite, Gyrodactylus turnbulli infecting its guppy host (Poecilia reticulata). Hosts were maintained at different densities (3, 6, 12 and 24 fish in 40 L aquaria), and we monitored gyrodactylids both at a population and individual host level. Although parasite population size increased with host density, the probability of an epidemic did not. Epidemics were more likely when the primary infected fish had a high mean intensity and duration of infection. Epidemics only occurred if the primary infected host experienced more than 23 worm days. Female guppies contracted infections sooner than males, probably because females have a higher propensity for shoaling. Conclusions/Significance These findings suggest that in social hosts like guppies, the frequency of social contact largely governs disease epidemics independent of host density.

Species distribution & antifungal susceptibility pattern of oropharyngeal Candida isolates from human immunodeficiency virus infected individuals

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Partha Pratim Das

2016-01-01

Results: From the 59 culture positive HIV seropositive cases, 61 Candida isolates were recovered; Candidaalbicans (n=47, 77.0%, C. dubliniensis (n=9, 14.7%, C. parapsilosis (n=2, 3.2%, C. glabrata (n=2, 3.2%, and C. famata (n=1, 1.6%. Candida colonization in HIV-seropositive individuals was significantly higher than that of HIV-seronegative (control group. Antifungal susceptibility testing revealed (n=6, 9.3% C. albicans isolates resistant to voriconazole and fluconazole by disk-diffusion method whereas no resistance was seen by Fungitest method. Interpretation & conclusions: C. albicans was the commonest Candida species infecting or colonizing HIV seropositive individuals. Oropharyngeal Candida isolates had high level susceptibility to all the major antifungals commonly in use. Increased level of immunosuppression in HIV-seropositives and drug resistance of non-albicans Candida species makes identification and susceptibility testing of Candida species necessary in different geographical areas of the country.

Differences in susceptibility of five cladoceran species to two systemic insecticides, imidacloprid and fipronil.

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Hayasaka, Daisuke; Korenaga, Tomoko; Suzuki, Kazutaka; Sánchez-Bayo, Francisco; Goka, Koichi

2012-03-01

Differences in susceptibility of five cladocerans to the neonicotinoid imidacloprid and the phenyl-pyrazole fipronil, which have been dominantly used in rice fields of Japan in recent years, were examined based on short-term (48-h), semi-static acute immobilization exposure tests. Additionally, we compared the species sensitivity distribution (SSD) patterns of both insecticides between two sets of species: the five tested cladocerans and all other aquatic organisms tested so far, using data from the ECOTOX database of U.S. Environmental Protection Agency (USEPA). The sensitivity of the test species to either imidacloprid or fipronil was consistent, spanning similar orders of magnitude (100 times). At the genus level, sensitivities to both insecticides were in the following descending order: Ceriodaphnia > Moina > Daphnia. A positive relationship was found between body lengths of each species and the acute toxicity (EC(50)) of the insecticides, in particular fipronil. Differences in SSD patterns of imidacloprid were found between the species groups compared, indicating that test cladocerans are much less susceptible than other aquatic species including amphibians, crustaceans, fish, insects, mollusks and worms. However, the SSD patterns for fipronil indicate no difference in sensitivity between cladocerans tested and other aquatic organisms despite the greater exposure, which overestimates the results, of our semi-static tests. From these results, Ceriodaphnia sp. should be considered as more sensitive bioindicators (instead of the standard Daphnia magna) for ecotoxicological assessments of aquatic ecosystems. In addition, we propose that ecotoxicity data associated with differences in susceptibility among species should be investigated whenever pesticides have different physicochemical properties and mode of action.

Stress responses in Streptococcus species and their effects on the host.

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Nguyen, Cuong Thach; Park, Sang-Sang; Rhee, Dong-Kwon

2015-11-01

Streptococci cause a variety of diseases, such as dental caries, pharyngitis, meningitis, pneumonia, bacteremia, endocarditis, erysipelas, and necrotizing fasciitis. The natural niche of this genus of bacteria ranges from the mouth and nasopharynx to the skin, indicating that the bacteria will inevitably be subjected to environmental changes during invasion into the host, where it is exposed to the host immune system. Thus, the Streptococcus-host interaction determines whether bacteria are cleared by the host's defenses or whether they survive after invasion to cause serious diseases. If this interaction was to be deciphered, it could aid in the development of novel preventive and therapeutic agents. Streptococcus species possess many virulent factors, such as peroxidases and heat-shock proteins (HSPs), which play key roles in protecting the bacteria from hostile host environments. This review will discuss insights into the mechanism(s) by which streptococci adapt to host environments. Additionally, we will address how streptococcal infections trigger host stress responses; however, the mechanism by which bacterial components modulate host stress responses remains largely unknown.

Endophytic Epichloë species and their grass hosts: from evolution to applications.

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Saikkonen, Kari; Young, Carolyn A; Helander, Marjo; Schardl, Christopher L

2016-04-01

The closely linked fitness of the Epichloë symbiont and the host grass is presumed to align the coevolution of the species towards specialization and mutually beneficial cooperation. Ecological observations demonstrating that Epichloë-grass symbioses can modulate grassland ecosystems via both above- and belowground ecosystem processes support this. In many cases the detected ecological importance of Epichloë species is directly or indirectly linked to defensive mutualism attributable to alkaloids of fungal-origin. Now, modern genetic and molecular techniques enable the precise studies on evolutionary origin of endophytic Epichloë species, their coevolution with host grasses and identification the genetic variation that explains phenotypic diversity in ecologically relevant characteristics of Epichloë-grass associations. Here we briefly review the most recent findings in these areas of research using the present knowledge of the genetic variation that explains the biosynthetic pathways driving the diversity of alkaloids produced by the endophyte. These findings underscore the importance of genetic interplay between the fungus and the host in shaping their coevolution and ecological role in both natural grass ecosystems, and in the agricultural arena.

Coagulase-negative Staphylococci in Danish blood cultures: species distribution and antibiotic susceptibility.

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Jarløv, J O; Højbjerg, T; Busch-Sørensen, C; Scheibel, J; Møller, J K; Kolmos, H J; Wandall, D A

1996-03-01

The distribution and antibiotic susceptibility of coagulase-negative staphylococci (CoNS) isolated from blood cultures was examined in samples from hospitals covering most of Denmark. A total of 499 CoNS isolates were detected in 477 blood cultures from 340 patients and speciated as Staphylococcus epidermidis, 285; Staphylococcus hominis, 61; Staphylococcus haemolyticus, 43; Staphylococcus warneri, 12; Staphylococcus cohnii, 7; Staphylococcus saprophyticus, 4; Staphylococcus capitis, 2 and Staphylococcus lugdunensis, 1. Seventy-eight isolates could not be identified to species level and six were Micrococcus spp. In 108 (22.6%) blood culture sets, more than one CoNS strain were found, as detected by species identification, antibiogram and biotyping. Significantly more blood cultures from patients in university hospitals were drawn from central venous catheters. Comparing university and non-university hospitals, the overall antibiotic susceptibility among CoNS was only slightly different, except for methicillin and amikacin. The prevalence of methicillin-resistant strains was 35.1% in the university hospital strains vs. 25.3% in the non-university hospital strains. The overall prevalence of methicillin resistance was 32%. Great geographic variation in both species distribution and antibiotic resistance was observed. The high prevalence of S. epidermidis makes subtyping of this species important.

Experimental infection of Aphanomyces invadans and susceptibility in seven species of tropical fish

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Seyedeh F. Afzali

2015-09-01

Full Text Available Aim: Epizootic ulcerative syndrome (EUS causes by aquatic oomycete fungus, Aphanomyces invadans is a dangerous fish disease of a wide range of fresh and brackish water, wild and farmed fish throughout the world. The objective of the present study was to determine the susceptibility of a number of tropical fish species to the EUS and compare the severity of infection between experimental groups. Materials and Methods: Snakehead, Channa striata (Bloch, 1793; snakeskin gourami, Trichopodus pectoralis (Regan, 1910; koi carp, Cyprinus carpio (Linnaeus, 1758; broadhead catfish, Clarias macrocephalus (Günther, 1864; goldfish, Carassius auratus (Linnaeus, 1758; climbing perch, Anabas testudineus (Bloch, 1792; and Nile tilapia, Oreochromis niloticus (Linnaeus, 1758 were challenged by intramuscular injection using zoospores of Aphanomyces invadans (NJM9701. The infected fish skins and muscles were examined for EUS histopathological characteristics, and the results on the severity of lesions and mortality were analyzed using SPSS program. Results: All zoospore-injected fish were shown to be susceptible to the EUS infection except Nile tilapia. Although, the general histopathological pattern was similar in the zoospore-injected group, but there were some variation in granulomatous reaction, that is the presence or absence of giant cells, and time of mortality were detected. The result of statistical analysis showed that there was a significant difference between species, (c2=145.11 and p<0.01. Conclusion: Gourami, koi carp, and catfish were demonstrated to be highly susceptible while goldfish and climbing perch were found to be moderately susceptible to the EUS infection. These findings suggested that the cellular response of fish to mycotic infection and granulomatous reaction varied in different fish species, which could not be an indicator of susceptibility or resistant to the EUS itself, although it was shown that the granulation rate and the level of

Non-Thermal Plasma Treatment Diminishes Fungal Viability and Up-Regulates Resistance Genes in a Plant Host

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Panngom, Kamonporn; Lee, Sang Hark; Park, Dae Hoon; Sim, Geon Bo; Kim, Yong Hee; Uhm, Han Sup; Park, Gyungsoon; Choi, Eun Ha

2014-01-01

Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance. PMID:24911947

Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

Directory of Open Access Journals (Sweden)

Kamonporn Panngom

Full Text Available Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

Spodoptera frugiperda (Lepidoptera: Noctuidae) host-plant variants: two host strains or two distinct species?

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Dumas, Pascaline; Legeai, Fabrice; Lemaitre, Claire; Scaon, Erwan; Orsucci, Marion; Labadie, Karine; Gimenez, Sylvie; Clamens, Anne-Laure; Henri, Hélène; Vavre, Fabrice; Aury, Jean-Marc; Fournier, Philippe; Kergoat, Gael J; d'Alençon, Emmanuelle

2015-06-01

The moth Spodoptera frugiperda is a well-known pest of crops throughout the Americas, which consists of two strains adapted to different host-plants: the first feeds preferentially on corn, cotton and sorghum whereas the second is more associated with rice and several pasture grasses. Though morphologically indistinguishable, they exhibit differences in their mating behavior, pheromone compositions, and show development variability according to the host-plant. Though the latter suggest that both strains are different species, this issue is still highly controversial because hybrids naturally occur in the wild, not to mention the discrepancies among published results concerning mating success between the two strains. In order to clarify the status of the two host-plant strains of S. frugiperda, we analyze features that possibly reflect the level of post-zygotic isolation: (1) first generation (F1) hybrid lethality and sterility; (2) patterns of meiotic segregation of hybrids in reciprocal second generation (F2), as compared to the meiosis of the two parental strains. We found a significant reduction of mating success in F1 in one direction of the cross and a high level of microsatellite markers showing transmission ratio distortion in the F2 progeny. Our results support the existence of post-zygotic reproductive isolation between the two laboratory strains and are in accordance with the marked level of genetic differentiation that was recovered between individuals of the two strains collected from the field. Altogether these results provide additional evidence in favor of a sibling species status for the two strains.

Diversity of susceptible hosts in canine distemper virus infection: a systematic review and data synthesis.

Science.gov (United States)

Martinez-Gutierrez, Marlen; Ruiz-Saenz, Julian

2016-05-12

Canine distemper virus (CDV) is the etiological agent of one of the most infectious diseases of domestic dogs, also known as a highly prevalent viral infectious disease of carnivores and posing a conservation threat to endangered species around the world. To get a better panorama of CDV infection in different Orders, a retrospective and documental systematic review of the role of CDV in different non-dog hosts was conducted. The bibliographical data were collected from MedLine/PubMed and Scopus databases. Data related to Order, Family, Genus and Species of the infected animals, the presence or absence of clinical signs, mortality, serological, molecular or antigenic confirmation of CDV infection, geographic location, were collected and summarized. Two hundred seventeen scientific articles were considered eligible which includes reports of serological evaluation, and antigenic or genomic confirmation of CDV infection in non-dog hosts. CDV infects naturally and experimentally different members of the Orders Carnivora (in 12 Families), Rodentia (four Families), Primates (two Families), Artiodactyla (three Families) and Proboscidea (one Family). The Order Carnivora (excluding domestic dogs) accounts for the vast majority (87.5%) of the records. Clinical disease associated with CDV infection was reported in 51.8% of the records and serological evidence of CDV infection in apparently healthy animals was found in 49.5% of the records. High mortality rate was showed in some of the recorded infections in Orders different to Carnivora. In non-dog hosts, CDV has been reported all continents with the exception of Australasia and in 43 different countries. The results of this systematic review demonstrate that CDV is able to infect a very wide range of host species from many different Orders and emphasizes the potential threat of infection for endangered wild species as well as raising concerns about potential zoonotic threats following the cessation of large-scale measles

Characterization and susceptibility patterns of clinically important Enterococcus species in eastern Nepal.

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Acharya, A; Khanal, A; Kanungo, R; Mohapatra, T

2007-12-01

Life threatening infections caused by enterococcus species with multidrug resistance has emerged as a threat to medical care in the present era. This study was conducted to characterize enterococcus species isolated from different clinical samples and to detect the pattern of susceptibility to some of the commonly used antibiotics in B.P Koirala Institute of Health Sciences (BPKIHS), a tertiary care hospital in eastern Nepal. Clinical samples submitted to the microbiology unit of Central Laboratory Service (CLS) for culture and sensitivity during March 2002 - February 2003 was analyzed. Enterococcus species were identified by colony characteristics, gram staining and relevant biochemical tests. Antibiotic susceptibility test was done by the Kirby Bauer disc diffusion technique. Of 50 Enterococcus species isolated, E. faecalis was the predominant isolate (48.0%) followed by E. faecium (32.0%) and E. avium (20.0%). Eighty-eight percent of E. faecalis showed sensitivity to cephotaxime and 87.0% to vancomycin. Multiple drug resistance was observed most commonly in E. faecium. Seventeen percent of E. faecium were resistant to vancomycin and 63.0% to ciprofloxacin and 44.0% to ampicillin. On the contrary E. avium rarely showed resistance to the antimicrobials tested including vancomycin. Enterococcal infections are common nowadays specially in hospitalized patients. Inappropriate use of antibiotics in clinical practice and poultry should be discouraged to prevent the emergence of multidrug resistant species.

Entomopathogenic Potential of Verticillium and Acremonium Species (Deuteromycotina: Hyphomycetes)

DEFF Research Database (Denmark)

Steenberg, Tove; Humber, Richard A

1999-01-01

their entomopathogenicity. A test was also conducted with a coleopteran (lesser mealworm, Alphitobius diaperinus) to further evaluate the host range for some of the fungi. V. lamellicola was not pathogenic to the two species of insects treated, while varying levels of pathogenicity were shown for the other species....... In general, V. lecanii was the most pathogenic species. Immature whiteflies appeared to be more susceptible to fungal infection than adult houseflies, and the host range for several of the fungi also included lesser mealworm....

Diversity, distribution and host-species associations of epiphytic orchids in Nepal

Czech Academy of Sciences Publication Activity Database

Timsina, B.; Rokaya, Maan Bahadur; Münzbergová, Zuzana; Kindlmann, P.; Shrestha, B.; Bhattarai, B.; Raskoti, B. B.

2016-01-01

Roč. 25, č. 13 (2016), s. 2803-2819 ISSN 0960-3115 Institutional support: RVO:67985939 Keywords : species richness * host * Nepal Himalaya Subject RIV: EF - Botanics Impact factor: 2.265, year: 2016

Response of brown-headed cowbirds and three host species to thinning treatments in low-elevation ponderosa pine forests along the northern Colorado Front Range

Science.gov (United States)

Keeley, W.H.; Germaine, Stephen S.; Stanley, Thomas R.; Spaulding, Sarah A.; Wanner, C.E.

2013-01-01

Thinning ponderosa pine (Pinus ponderosa) forests to achieve desired ecological conditions remains a priority in the North American west. In addition to reducing the risk of high-severity wildfires in unwanted areas, stand thinning may increase wildlife and plant diversity and provide increased opportunity for seedling recruitment. We initiated conservative (i.e. minimal removal of trees) ponderosa stand thinning treatments with the goals of reducing fire risk and improving habitat conditions for native wildlife and flora. We then compared site occupancy of brown-headed cowbirds (Molothrus ater), chipping sparrows (Spizella passerina), plumbeous vireos (Vireo plumbeus), and western wood-pewees (Contopus sordidulus) in thinned and unthinned (i.e., control) forest stands from 2007 to 2009. Survey stations located in thinned stands had 64% fewer trees/ha, 25% less canopy cover, and 23% less basal area than stations in control stands. Occupancy by all three host species was negatively associated with tree density, suggesting that these species respond favorably to forest thinning treatments in ponderosa pine forests. We also encountered plumbeous vireos more frequently in plots closer to an ecotonal (forest/grassland) edge, an association that may increase their susceptibility to edge-specialist, brood parasites like brown-headed cowbirds. Occupancy of brown-headed cowbirds was not related to forest metrics but was related to occupancy by plumbeous vireos and the other host species in aggregate, supporting previous reports on the affiliation between these species. Forest management practices that promote heterogeneity in forest stand structure may benefit songbird populations in our area, but these treatments may also confer costs associated with increased cowbird occupancy. Further research is required to understand more on the complex relationships between occupancy of cowbirds and host species, and between cowbird occupancy and realized rates of nest parasitism.

Susceptibility and antibody response of Vesper Sparrows (Pooecetes gramineus) to West Nile virus: A potential amplification host in sagebrush-grassland habitat

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Hofmeister, Erik K.; Dusek, Robert J.; Fassbinder-Orth, Carol; Owen, Benjamin; Franson, J. Christian

2016-01-01

West Nile virus (WNV) spread to the US western plains states in 2003, when a significant mortality event attributed to WNV occurred in Greater Sage-grouse ( Centrocercus urophasianus ). The role of avian species inhabiting sagebrush in the amplification of WNV in arid and semiarid regions of the North America is unknown. We conducted an experimental WNV challenge study in Vesper Sparrows ( Pooecetes gramineus ), a species common to sagebrush and grassland habitats found throughout much of North America. We found Vesper Sparrows to be moderately susceptible to WNV, developing viremia considered sufficient to transmit WNV to feeding mosquitoes, but the majority of birds were capable of surviving infection and developing a humoral immune response to the WNV nonstructural 1 and envelope proteins. Despite clearance of viremia, after 6 mo, WNV was detected molecularly in three birds and cultured from one bird. Surviving Vesper Sparrows were resistant to reinfection 6 mo after the initial challenge. Vesper sparrows could play a role in the amplification of WNV in sagebrush habitat and other areas of their range, but rapid clearance of WNV may limit their importance as competent amplification hosts of WNV.

Susceptibility of ectomycorrhizal fungi to soil heating.

Science.gov (United States)

Kipfer, Tabea; Egli, Simon; Ghazoul, Jaboury; Moser, Barbara; Wohlgemuth, Thomas

2010-01-01

Ectomycorrhizal (EcM) fungi are an important biotic factor for successful tree recruitment because they enhance plant growth and alleviate drought stress of their hosts. Thus, EcM propagules are expected to be a key factor for forest regeneration after major disturbance events such as stand-replacing forest fires. Yet the susceptibility of soil-borne EcM fungi to heat is unclear. In this study, we investigated the heat tolerance of EcM fungi of Scots pine (Pinus sylvestris L., Pinaceae). Soil samples of three soil depths were heated to the temperature of 45, 60 and 70 °C, respectively, and surviving EcM fungi were assessed by a bioassay using Scots pine as an experimental host plant. EcM species were identified by a combination of morphotyping and sequencing of the ITS region. We found that mean number of species per sample was reduced by the 60 and 70 °C treatment, but not by the 45 °C treatment. Species composition changed due to heat. While some EcM fungi species did not survive heating, the majority of species was also found in the heated samples. The most frequent species in the heat treatment were Rhizopogon roseolus, Cenococcum geophilum and several unidentified species. Copyright © 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Antimicrobial susceptibility patterns of Ureaplasma species and Mycoplasma hominis in pregnant women.

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Redelinghuys, Mathys J; Ehlers, Marthie M; Dreyer, Andries W; Lombaard, Hennie A; Kock, Marleen M

2014-03-28

Genital mycoplasmas colonise up to 80% of sexually mature women and may invade the amniotic cavity during pregnancy and cause complications. Tetracyclines and fluoroquinolones are contraindicated in pregnancy and erythromycin is often used to treat patients. However, increasing resistance to common antimicrobial agents is widely reported. The purpose of this study was to investigate antimicrobial susceptibility patterns of genital mycoplasmas in pregnant women. Self-collected vaginal swabs were obtained from 96 pregnant women attending an antenatal clinic in Gauteng, South Africa. Specimens were screened with the Mycofast Revolution assay for the presence of Ureaplasma species and Mycoplasma hominis. The antimicrobial susceptibility to levofloxacin, moxifloxacin, erythromycin, clindamycin and tetracycline were determined at various breakpoints. A multiplex polymerase chain reaction assay was used to speciate Ureaplasma positive specimens as either U. parvum or U. urealyticum. Seventy-six percent (73/96) of specimens contained Ureaplasma spp., while 39.7% (29/73) of Ureaplasma positive specimens were also positive for M. hominis. Susceptibilities of Ureaplasma spp. to levofloxacin and moxifloxacin were 59% (26/44) and 98% (43/44) respectively. Mixed isolates (Ureaplasma species and M. hominis) were highly resistant to erythromycin and tetracycline (both 97% resistance). Resistance of Ureaplasma spp. to erythromycin was 80% (35/44) and tetracycline resistance was detected in 73% (32/44) of Ureaplasma spp. Speciation indicated that U. parvum was the predominant Ureaplasma spp. conferring antimicrobial resistance. Treatment options for genital mycoplasma infections are becoming limited. More elaborative studies are needed to elucidate the diverse antimicrobial susceptibility patterns found in this study when compared to similar studies. To prevent complications in pregnant women, the foetus and the neonate, routine screening for the presence of genital mycoplasmas is

Effects of host species and environment on the skin microbiome of Plethodontid salamanders

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Muletz-Wolz, Carly R.; Yarwood, Stephanie A.; Grant, Evan H. Campbell; Fleischer, Robert C.; Lips, Karen R.

2018-01-01

The amphibian skin microbiome is recognized for its role in defence against pathogens, including the deadly fungal pathogen Batrachochytrium dendrobatidis (Bd). Yet, we have little understanding of evolutionary and ecological processes that structure these communities, especially for salamanders and closely related species. We investigated patterns in the distribution of bacterial communities on Plethodon salamander skin across host species and environments.Quantifying salamander skin microbiome structure contributes to our understanding of how host-associated bacteria are distributed across the landscape, among host species, and their putative relationship with disease.We characterized skin microbiome structure (alpha-diversity, beta-diversity and bacterial operational taxonomic unit [OTU] abundances) using 16S rRNA gene sequencing for co-occurring Plethodon salamander species (35 Plethodon cinereus, 17 Plethodon glutinosus, 10 Plethodon cylindraceus) at three localities to differentiate the effects of host species from environmental factors on the microbiome. We sampled the microbiome of P. cinereus along an elevational gradient (n = 50, 700–1,000 m a.s.l.) at one locality to determine whether elevation predicts microbiome structure. Finally, we quantified prevalence and abundance of putatively anti-Bd bacteria to determine if Bd-inhibitory bacteria are dominant microbiome members.Co-occurring salamanders had similar microbiome structure, but among sites salamanders had dissimilar microbiome structure for beta-diversity and abundance of 28 bacterial OTUs. We found that alpha-diversity increased with elevation, beta-diversity and the abundance of 17 bacterial OTUs changed with elevation (16 OTUs decreasing, 1 OTU increasing). We detected 11 putatively anti-Bd bacterial OTUs that were present on 90% of salamanders and made up an average relative abundance of 83% (SD ± 8.5) per salamander. All salamanders tested negative for Bd.We conclude that

Genes, communities & invasive species: understanding the ecological and evolutionary dynamics of host-pathogen interactions.

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Burdon, J J; Thrall, P H; Ericson, L

2013-08-01

Reciprocal interactions between hosts and pathogens drive ecological, epidemiological and co-evolutionary trajectories, resulting in complex patterns of diversity at population, species and community levels. Recent results confirm the importance of negative frequency-dependent rather than 'arms-race' processes in the evolution of individual host-pathogen associations. At the community level, complex relationships between species abundance and diversity dampen or alter pathogen impacts. Invasive pathogens challenge these controls reflecting the earliest stages of evolutionary associations (akin to arms-race) where disease effects may be so great that they overwhelm the host's and community's ability to respond. Viewing these different stabilization/destabilization phases as a continuum provides a valuable perspective to assessment of the role of genetics and ecology in the dynamics of both natural and invasive host-pathogen associations. Copyright © 2013 Elsevier Ltd. All rights reserved.

Brown dog tick, Rhipicephalus sanguineus sensu lato, infestation of susceptible dog hosts is reduced by slow release of semiochemicals from a less susceptible host.

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de Oliveira Filho, Jaires Gomes; Ferreira, Lorena Lopes; Sarria, André Lucio Franceschini; Pickett, John A; Birkett, Michael A; Mascarin, Gabriel Moura; de León, Adalberto A Pérez; Borges, Lígia Miranda Ferreira

2017-01-01

Domestic dog breeds are hosts for the brown dog tick, Rhipicephalus sanguineus sensu lato, but infestation levels vary among breeds. Beagles are less susceptible to tick infestations than English cocker spaniels due to enhanced production of 2-hexanone and benzaldehyde that act as volatile tick repellents. We report the use of prototype slow-release formulations of these compounds to reduce the burden of R. sanguineus s. l. on English cocker spaniel dogs. Twelve dogs were randomly assigned to two groups with six dogs each. The treated group received collars with slow-release formulations of the compounds attached, while the control group received collars with clean formulations attached. Five environmental infestations were performed, with the number of ticks (at all stages) on the dogs being counted twice a day for 45days. The counts on the number of tick stages found per dog were individually fitted to linear mixed effects models with repeated measures and normal distribution for errors. The mean tick infestation in the treated group was significantly lower than in the control group. For larvae and nymphs, a decrease in tick infestation was observed at the fifth count, and for adults, lower average counts were observed in all counts. The compounds did not interfere with the distribution of the ticks on the body of the dogs, as a similar percentage of ticks was found on the anterior half of the dogs (54.5% for the control group and 56.2% for the treated group). The biological and reproductive parameters of the ticks were not affected by the repellents. This study highlights for the first time the potential use of a novel allomone (repellent)-based formulation for reduction of tick infestation on susceptible dogs. Copyright © 2016 Elsevier GmbH. All rights reserved.

Toxocara cati (Nematoda, Ascarididae in different wild feline species in Brazil: new host records

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Moisés Gallas

2013-05-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2013v26n3p117 This is the first detailed description of Toxocara cati parasitizing felines in South America. Seventeen run over wild felines (Leopardus colocolo, Leopardus geoffroyi, Leopardus tigrinus, and Puma yagouaroundi were collected from different towns in the State of Rio Grande do Sul, Brazil. The morphometry of males and females allowed the identification of specimens as being T. cati. The helminths were found in the stomach and intestine of hosts with prevalences of 66.6% in L. colocolo, L. geoffroyi, and L. tigrinus; and 60% in P. yagouaroundi. The ecological parameters were calculated for each host and L. colocolo had the highest infection intensity (22.5 helminths/ host. This is the first report of T. cati parasitizing four wild felines species in southern Brazil, besides a new record of this parasite for two host species.

The path to host extinction can lead to loss of generalist parasites.

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Farrell, Maxwell J; Stephens, Patrick R; Berrang-Ford, Lea; Gittleman, John L; Davies, T Jonathan

2015-07-01

Host extinction can alter disease transmission dynamics, influence parasite extinction and ultimately change the nature of host-parasite systems. While theory predicts that single-host parasites are among the parasite species most susceptible to extinction following declines in their hosts, documented parasite extinctions are rare. Using a comparative approach, we investigate how the richness of single-host and multi-host parasites is influenced by extinction risk among ungulate and carnivore hosts. Host-parasite associations for free-living carnivores (order Carnivora) and terrestrial ungulates (orders Perissodactyla + Cetartiodactyla minus cetaceans) were merged with host trait data and IUCN Red List status to explore the distribution of single-host and multi-host parasites among threatened and non-threatened hosts. We find that threatened ungulates harbour a higher proportion of single-host parasites compared to non-threatened ungulates, which is explained by decreases in the richness of multi-host parasites. However, among carnivores threat status is not a significant predictor of the proportion of single-host parasites, or the richness of single-host or multi-host parasites. The loss of multi-host parasites from threatened ungulates may be explained by decreased cross-species contact as hosts decline and habitats become fragmented. Among carnivores, threat status may not be important in predicting patterns of parasite specificity because host decline results in equal losses of both single-host parasites and multi-host parasites through reduction in average population density and frequency of cross-species contact. Our results contrast with current models of parasite coextinction and highlight the need for updated theories that are applicable across host groups and account for both inter- and intraspecific contact. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Rotaxane and catenane host structures for sensing charged guest species.

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Langton, Matthew J; Beer, Paul D

2014-07-15

CONSPECTUS: The promise of mechanically interlocked architectures, such as rotaxanes and catenanes, as prototypical molecular switches and shuttles for nanotechnological applications, has stimulated an ever increasing interest in their synthesis and function. The elaborate host cavities of interlocked structures, however, can also offer a novel approach toward molecular recognition: this Account describes the use of rotaxane and catenane host systems for binding charged guest species, and for providing sensing capability through an integrated optical or electrochemical reporter group. Particular attention is drawn to the exploitation of the unusual dynamic properties of interlocked molecules, such as guest-induced shuttling or conformational switching, as a sophisticated means of achieving a selective and functional sensor response. We initially survey interlocked host systems capable of sensing cationic guests, before focusing on our accomplishments in synthesizing rotaxanes and catenanes designed for the more challenging task of selective anion sensing. In our group, we have developed the use of discrete anionic templation to prepare mechanically interlocked structures for anion recognition applications. Removal of the anion template reveals an interlocked host system, possessing a unique three-dimensional geometrically restrained binding cavity formed between the interlocked components, which exhibits impressive selectivity toward complementary anionic guest species. By incorporating reporter groups within such systems, we have developed both electrochemical and optical anion sensors which can achieve highly selective sensing of anionic guests. Transition metals, lanthanides, and organic fluorophores integrated within the mechanically bonded structural framework of the receptor are perturbed by the binding of the guest, with a concomitant change in the emission profile. We have also exploited the unique dynamics of interlocked hosts by demonstrating that an

Helminth species richness of introduced and native grey mullets (Teleostei: Mugilidae).

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Sarabeev, Volodimir

2015-08-01

Quantitative complex analyses of parasite communities of invaders across different native and introduced populations are largely lacking. The present study provides a comparative analysis of species richness of helminth parasites in native and invasive populations of grey mullets. The local species richness differed between regions and host species, but did not differ when compared with invasive and native hosts. The size of parasite assemblages of endohelminths was higher in the Mediterranean and Azov-Black Seas, while monogeneans were the most diverse in the Sea of Japan. The helminth diversity was apparently higher in the introduced population of Liza haematocheilus than that in their native habitat, but this trend could not be confirmed when the size of geographic range and sampling efforts were controlled for. The parasite species richness at the infracommunity level of the invasive host population is significantly lower compared with that of the native host populations that lends support to the enemy release hypothesis. A distribution pattern of the infracommunity richness of acquired parasites by the invasive host can be characterized as aggregated and it is random in native host populations. Heterogeneity in the host susceptibility and vulnerability to acquired helminth species was assumed to be a reason of the aggregation of species numbers in the population of the invasive host. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Candida Species From Eye Infections: Drug Susceptibility, Virulence Factors, and Molecular Characterization.

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Ranjith, Konduri; Sontam, Bhavani; Sharma, Savitri; Joseph, Joveeta; Chathoth, Kanchana N; Sama, Kalyana C; Murthy, Somasheila I; Shivaji, Sisinthy

2017-08-01

To determine the type of Candida species in ocular infections and to investigate the relationship of antifungal susceptibility profile to virulence factors. Fifty isolates of yeast-like fungi from patients with keratitis, endophthalmitis, and orbital cellulitis were identified by Vitek-2 compact system and DNA sequencing of ITS1-5.8S-ITS2 regions of the rRNA gene, followed by phylogenetic analysis for phenotypic and genotypic identification, respectively. Minimum inhibitory concentration of six antifungal drugs was determined by E test/microbroth dilution methods. Phenotypic and genotypic methods were used to determine the virulence factors. Phylogenetic analysis showed the clustering of all isolates into eight distinct groups with a major cluster formed Candida parapsilosis (n = 21), which was the most common species by both Vitek 2 and DNA sequencing. Using χ2 test no significant difference was noted between the techniques except that Vitek 2 did not identify C. viswanathii, C. orthopsilosis, and two non-Candida genera. Of 43 tested Candida isolates high susceptibility to amphotericin B (39/43, 90.6%) and natamycin (43/43, 100%) was noted. While none of the isolates produced coagulase, all produced esterase and catalase. The potential to form biofilm was detected in 23/43 (53.4%) isolates. Distribution of virulence factors by heat map analysis showed difference in metabolic activity of biofilm producers from nonbiofilm producers. Identified by Vitek 2 and DNA sequencing methods C. parapsilosis was the most common species associated with eye infections. Irrespective of the virulence factors elaborated, the Candida isolates were susceptible to commonly used antifungal drugs such as amphotericin B and natamycin.

The trend of susceptibilities to amphotericin B and fluconazole of Candida species from 1999 to 2002 in Taiwan

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Cheng Hsiao-Hsu

2005-11-01

Full Text Available Abstract Background Candida species have various degrees of susceptibility to common antifungal drugs. The extent of resistance to amphotericin B and fluconazole of Candida glabrata isolates causing candidemia has been reported. Active surveillance may help us to monitor the trend of susceptibility to antifungal drugs and to determine if there is an emerging co-resistance to both drugs of Candida species, specifically, of C. glabrata in Taiwan. Methods The susceptibilities to amphotericin B and fluconazole of Candida species collected in 1999 and 2002 of the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY were determined by the microdilution method. Results The antifungal susceptibilities of 342 and 456 isolates collected from 11 hospitals participating in both TSARY 1999 and TSARY 2002, respectively, have been determined. The resistance rate to amphotericin B has increased from 0.3% in the TSARY1999 to 2.2% in the TSARY 2002. In contrast, the resistance rate to fluconazole has decreased from 8.8% to 2.2%. Nevertheless, significantly more C. glabrata isolates were not susceptible to fluconazole in the TSARY 2002 (47.4% than that in the TSARY 1999 (20.8%. There were 9.8% and 11% of C. glabrata isolates having susceptible-dose dependent and resistant phenotype to fluconazole in the TSARY 1999, verse 45.3% and 2.1% in the TSARY 2002. Conclusion There was an increase of resistance rate to amphotericin B in C. glabrata. On the other hand, although the resistance rate to fluconazole has decreased, almost half of C. glabrata isolates were not susceptible to this drug. Hence, continuous monitoring the emerging of co-resistance to both amphotericin B and fluconazole of Candida species, specifically, of C. glabrata, will be an important early-warning system.

Generic amyloidogenicity of mammalian prion proteins from species susceptible and resistant to prions.

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Nyström, Sofie; Hammarström, Per

2015-05-11

Prion diseases are lethal, infectious diseases associated with prion protein (PrP) misfolding. A large number of mammals are susceptible to both sporadic and acquired prion diseases. Although PrP is highly conserved and ubiquitously expressed in all mammals, not all species exhibit prion disease. By employing full length recombinant PrP from five known prion susceptible species (human, cattle, cat, mouse and hamster) and two species considered to be prion resistant (pig and dog) the amyloidogenicity of these PrPs has been delineated. All the mammalian PrPs, even from resistant species, were swiftly converted from the native state to amyloid-like structure when subjected to a native condition conversion assay. The PrPs displayed amyloidotypic tinctorial and ultrastructural hallmarks. Self-seeded conversion of the PrPs displayed significantly decreased lag phases demonstrating that nucleation dependent polymerization is a dominating mechanism in the fibrillation process. Fibrils from Aβ1-40, Aβ1-42, Lysozyme, Insulin and Transthyretin did not accelerate conversion of HuPrP whereas fibrils from HuPrP90-231 and HuPrP121-231 as well as full length PrPs of all PrPs efficiently seeded conversion showing specificity of the assay requiring the C-terminal PrP sequence. Our findings have implications for PrP misfolding and could have ramifications in the context of prion resistant species and silent carriers.

Host social behavior and parasitic infection: A multifactorial approach

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Ezenwa, V.O.

2004-01-01

I examined associations between several components of host social organization, including group size and gregariousness, group stability, territoriality and social class, and gastrointestinal parasite load in African bovids. At an intraspecific level, group size was positively correlated with parasite prevalence, but only when the parasite was relatively host specific and only among host species living in stable groups. Social class was also an important predictor of infection rates. Among gazelles, territorial males had higher parasite intensities than did either bachelor males or females and juveniles, suggesting that highly territorial individuals may be either more exposed or more susceptible to parasites. Associations among territoriality, grouping, and parasitism were also found across taxa. Territorial host genera were more likely to be infected with strongyle nematodes than were nonterritorial hosts, and gregarious hosts were more infected than were solitary hosts. Analyses also revealed that gregariousness and territoriality had an interactive effect on individual parasite richness, whereby hosts with both traits harbored significantly more parasite groups than did hosts with only one or neither trait. Overall, study results indicate that multiple features of host social behavior influence infection risk and suggest that synergism between traits also has important effects on host parasite load.

Susceptibility of Seven Termite Species (Isoptera) to the Entomopathogenic Fungus Metarhizium anisopliae

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Chouvenc , Thomas; Su , Nan-Yao; Robert , Alain

2009-01-01

Seven termite species (Isoptera) from five families were tested for disease susceptibility against the entomopathogenic fungus Metarhizium anisopliae using a standard protocol: Mastotermes darwiniensis (Mastotermitidae), Hodotermopsis sjoestedti (Termopsidae), Hodotermes mossambicus (Hodotermitidae), Kalotermes flavicollis (Kalotermitidae), Reticulitermes flavipes and Prorhinotermes canalifrons (Rhinotermitidae), and Nasutitermes voeltzkowi (Termitidae). Our results showed a large diversity i...

Ability of a Generalist Seed Beetle to Colonize an Exotic Host: Effects of Host Plant Origin and Oviposition Host.

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Amarillo-Suárez, A; Repizo, A; Robles, J; Diaz, J; Bustamante, S

2017-08-01

The colonization of an exotic species by native herbivores is more likely to occur if that herbivore is a generalist. There is little information on the life-history mechanisms used by native generalist insects to colonize exotic hosts and how these mechanisms are affected by host properties. We examined the ability of the generalist seed beetle Stator limbatus Horn to colonize an exotic species. We compared its host preference, acceptability, performance, and egg size when ovipositing and developing on two native (Pithecellobium dulce (Roxb.) Benth and Senegalia riparia (Kunth)) and one exotic legume species (Leucaena leucocephala (Lam.)). We also analyzed the seed chemistry. We found that females recognize the exotic species as an unfavorable host for larval development and that they delayed oviposition and laid fewer and larger eggs on the exotic species than on the native species. Survivorship on the exotic host was 0%. Additionally, seeds of the native species contain five chemical compounds that are absent in the exotic species, and the exotic species contains three sterols, which are absent in the native legumes. Genetically based differences between beetles adapted to different hosts, plastic responses toward new hosts, and chemical differences among seeds are important in host colonization and recognition of the exotic host. In conclusion, the generalist nature of S. limbatus does not influence its ability to colonize L. leucocephala. Explanations for the colonization of exotic hosts by generalist native species and for the success of invasive species must be complemented with studies measuring local adaptation and plasticity.

The Effect of Host-Plant Phylogenetic Isolation on Species Richness, Composition and Specialization of Insect Herbivores: A Comparison between Native and Exotic Hosts.

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Julio Miguel Grandez-Rios

Full Text Available Understanding the drivers of plant-insect interactions is still a key issue in terrestrial ecology. Here, we used 30 well-defined plant-herbivore assemblages to assess the effects of host plant phylogenetic isolation and origin (native vs. exotic on the species richness, composition and specialization of the insect herbivore fauna on co-occurring plant species. We also tested for differences in such effects between assemblages composed exclusively of exophagous and endophagous herbivores. We found a consistent negative effect of the phylogenetic isolation of host plants on the richness, similarity and specialization of their insect herbivore faunas. Notably, except for Jaccard dissimilarity, the effect of phylogenetic isolation on the insect herbivore faunas did not vary between native and exotic plants. Our findings show that the phylogenetic isolation of host plants is a key factor that influences the richness, composition and specialization of their local herbivore faunas, regardless of the host plant origin.

Discrimination of the Social Parasite Ectatomma parasiticum by Its Host Sibling Species (E. tuberculatum

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Renée Fénéron

2013-01-01

Full Text Available Among social parasites, workerless inquilines entirely depend on their host for survival and reproduction. They are usually close phylogenetic relatives of their host, which raises important questions about their evolutionary history and mechanisms of speciation at play. Here we present new findings on Ectatomma parasiticum, the only inquiline ant described in the Ectatomminae subfamily. Field data confirmed its rarity and local distribution in a facultative polygynous population of E. tuberculatum in Mexico. Genetic analyses demonstrated that the parasite is a sibling species of its host, from which it may have diverged recently. Polygyny is suggested to have favored the evolution of social parasite by sympatric speciation. Nevertheless, host workers from this population were able to discriminate parasites from their conspecifics. They treated the parasitic queens either as individuals of interest or as intruders, depending on their colonial origin, probably because of the peculiar chemical profile of the parasites and/or their reproductive status. We suggest that E. parasiticum could have conserved from its host sibling species the queen-specific substances that produce attracting and settling effect on workers, which, in return, would increase the probability to be detected. This hypothesis could explain the imperfect social integration of the parasite into host colonies.

Host-to-host variation of ecological interactions in polymicrobial infections

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Mukherjee, Sayak; Weimer, Kristin E.; Seok, Sang-Cheol; Ray, Will C.; Jayaprakash, C.; Vieland, Veronica J.; Swords, W. Edward; Das, Jayajit

2015-02-01

Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host-microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species.

Host-to-host variation of ecological interactions in polymicrobial infections.

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Mukherjee, Sayak; Weimer, Kristin E; Seok, Sang-Cheol; Ray, Will C; Jayaprakash, C; Vieland, Veronica J; Swords, W Edward; Das, Jayajit

2014-12-04

Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host-microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species.

Assessment of oxidant susceptibility of red blood cells in various species based on cell deformability.

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Simmonds, Michael J; Meiselman, Herbert J; Marshall-Gradisnik, Sonya M; Pyne, Michael; Kakanis, Michael; Keane, James; Brenu, Ekua; Christy, Rhys; Baskurt, Oguz K

2011-01-01

The present study was designed to investigate the oxidant susceptibility of red blood cells (RBC) from four species (echidna, human, koala, Tasmanian devil) based on changes in cellular deformability. These species were specifically chosen based on differences in lifestyle and/or biology associated with varied levels of oxidative stress. The major focus was the influence of superoxide radicals generated within the cell (phenazine methosulfate, PMS, 50 μM) or in the extracellular medium (xanthine oxidase-hypoxanthine, XO-HX, 0.1 U/ml XO) on RBC deformability at various shear stresses (SS). RBC deformability was assessed by laser-diffraction analysis using a "slit-flow ektacytometer". Both superoxide-generating treatments resulted in significant increases of methemoglobin for all species (p koala cells exhibited a similar sigmoid-like response to SS, short-beaked echidna values were markedly lower and only increased slightly with SS, while Tasmanian devil RBC were extremely rigid. The effect of XO-HX on RBC deformability was less when compared with PMS (i.e., smaller increase in rigidity) with the exception of Tasmanian devil RBC which exhibited essentially no deformation even at the highest SS; Tasmanian devil RBC response to XO-HX was thus comparable to that observed with PMS. Our findings indicate that ektacytometry can be used to determine the oxidant susceptibility of RBC from different species which varies significantly among mammals representing diverse lifestyles and evolutionary histories. These differences in susceptibility are consistent with species-specific discrepancies between observed and allometrically-predicted life spans and are compatible with the oxidant theory of aging.

Plants of the fynbos biome harbour host species-specific bacterial communities.

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Miyambo, Tsakani; Makhalanyane, Thulani P; Cowan, Don A; Valverde, Angel

2016-08-01

The fynbos biome in South Africa is globally recognised as a plant biodiversity hotspot. However, very little is known about the bacterial communities associated with fynbos plants, despite interactions between primary producers and bacteria having an impact on the physiology of both partners and shaping ecosystem diversity. This study reports on the structure, phylogenetic composition and potential roles of the endophytic bacterial communities located in the stems of three fynbos plants (Erepsia anceps, Phaenocoma prolifera and Leucadendron laureolum). Using Illumina MiSeq 16S rRNA sequencing we found that different subpopulations of Deinococcus-Thermus, Alphaproteobacteria, Acidobacteria and Firmicutes dominated the endophytic bacterial communities. Alphaproteobacteria and Actinobacteria were prevalent in P. prolifera, whereas Deinococcus-Thermus dominated in L. laureolum, revealing species-specific host-bacteria associations. Although a high degree of variability in the endophytic bacterial communities within hosts was observed, we also detected a core microbiome across the stems of the three plant species, which accounted for 72% of the sequences. Altogether, it seems that both deterministic and stochastic processes shaped microbial communities. Endophytic bacterial communities harboured putative plant growth-promoting bacteria, thus having the potential to influence host health and growth. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Molecular identification and in-vitro antifungal susceptibility testing of Candida species isolated from patients with onychomycosis

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Keyvan Pakshir

2015-03-01

Full Text Available Background and Purpose: Candida species are the most opportunistic fungi affecting the nails and resulting in onychomycosis. In this study, we identified and evaluated in-vitro susceptibility of the recovered isolates against fluconazole (FLC, voriconazole (VRC, and clotrimazole (CLT using the Clinical and Laboratory Standards Institute (CLSI M27-A3 document. Materials and Methods: From patients with either clinically or mycologically proven onychomycosis, 97 isolates comprising of seven Candida species were isolated, which were identified by both conventional and molecular techniques such as polymerase chain reaction-restriction fragment length polymorphism. In addition, Candida dubliniensis was confirmed by restriction endonuclease analysis. Antifungal susceptibility of each isolate against the three azoles applied in this study was determined using the CLSI microdilution reference method M27-A3. Results: Candida parapsilosis (C. parapsilosis was the most frequently isolated species (n=44, followed by C. albicans (n=23, C. tropicalis (n=13, C. glabrata (n=7, C. krusei (n=6, C. guilliermondii (n=3, and C. dubliniensis (n=1. All the isolates were susceptible to CLT. VRC had lower minimum inhibitory concentration (MIC values for the isolates compared to FLC. Geometric mean MIC values of VRC, FLC, and CLT for C. parapsilosis isolates were 0.07 µg/ml, 0.8 µg/ml, and 0.35 µg/ml, respectively. Collectively, all species exhibited greater susceptibility to VRC in comparison to C. albicans (P≤0.001. Conclusion: This study showed that non-albicans Candida species were the most common etiologic agents of non-dermatophyte onychomycosis. The major antifungal agents used in clinics to empirically treat yeast onychomycosis are FLC and CLT. Our data suggested that CLT is a better choice for the treatment of Candida onychomycosis, especially in drug resistant cases.

Uncovering the drivers of host-associated microbiota with joint species distribution modelling.

Science.gov (United States)

Björk, Johannes R; Hui, Francis K C; O'Hara, Robert B; Montoya, Jose M

2018-06-01

In addition to the processes structuring free-living communities, host-associated microbiota are directly or indirectly shaped by the host. Therefore, microbiota data have a hierarchical structure where samples are nested under one or several variables representing host-specific factors, often spanning multiple levels of biological organization. Current statistical methods do not accommodate this hierarchical data structure and therefore cannot explicitly account for the effect of the host in structuring the microbiota. We introduce a novel extension of joint species distribution models (JSDMs) which can straightforwardly accommodate and discern between effects such as host phylogeny and traits, recorded covariates such as diet and collection site, among other ecological processes. Our proposed methodology includes powerful yet familiar outputs seen in community ecology overall, including (a) model-based ordination to visualize and quantify the main patterns in the data; (b) variance partitioning to assess how influential the included host-specific factors are in structuring the microbiota; and (c) co-occurrence networks to visualize microbe-to-microbe associations. © 2018 John Wiley & Sons Ltd.

(macro- Evolutionary ecology of parasite diversity: From determinants of parasite species richness to host diversification

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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.

Host-to-host variation of ecological interactions in polymicrobial infections

International Nuclear Information System (INIS)

Mukherjee, Sayak; Seok, Sang-Cheol; Ray, Will C; Jayaprakash, C; Vieland, Veronica J; Das, Jayajit; Weimer, Kristin E; Swords, W Edward

2015-01-01

Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host–microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species. (paper)

[Validation of the modified algorithm for predicting host susceptibility to viruses taking into account susceptibility parameters of primary target cell cultures and natural immunity factors].

Science.gov (United States)

Zhukov, V A; Shishkina, L N; Safatov, A S; Sergeev, A A; P'iankov, O V; Petrishchenko, V A; Zaĭtsev, B N; Toporkov, V S; Sergeev, A N; Nesvizhskiĭ, Iu V; Vorob'ev, A A

2010-01-01

The paper presents results of testing a modified algorithm for predicting virus ID50 values in a host of interest by extrapolation from a model host taking into account immune neutralizing factors and thermal inactivation of the virus. The method was tested for A/Aichi/2/68 influenza virus in SPF Wistar rats, SPF CD-1 mice and conventional ICR mice. Each species was used as a host of interest while the other two served as model hosts. Primary lung and trachea cells and secretory factors of the rats' airway epithelium were used to measure parameters needed for the purpose of prediction. Predicted ID50 values were not significantly different (p = 0.05) from those experimentally measured in vivo. The study was supported by ISTC/DARPA Agreement 450p.

Species Distribution and Susceptibility to Azoles of Vaginal Yeasts Isolated Prostitutes

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Norma T. Gross

2007-01-01

Full Text Available Objective. We investigated the use of miconazole among female prostitutes in Costa Rica as well as the distribution of vaginal yeasts and the susceptibility pattern to azoles of strains obtained from this population. Our intention was to relate a frequent use of miconazole to occurrence of vaginal yeasts resistant to azoles. Methods. Vaginal samples were taken from 277 patients that have previously used azoles. Vaginal swabs were obtained for direct microscopy and culture. Yeast isolates were identified by germ tube test and assimilation pattern. Susceptibility testing was determined using a tablet diffusion method. Results. The number of clinical Candida isolates (one from each patient was 57 (20.6%. C. albicans was the predominant species (70%, followed by C. parapsilosis (12%, C. tropicalis (5.3%, C. glabrata and C. famata (3.5% each, C. krusei, C. inconspicua and C. guilliermondii (1.7% each. The majority of vaginal Candida isolates were susceptible to ketoconazole (91%, fluconazole (96.5%, and itraconazole (98%. A lower susceptibility of some isolates to miconazole (63% was observed as compared to the other azoles tested. Moreover, the strains, nonsusceptible to miconazole, were more often obtained from patients that have used this antifungal at least four times within the last year before taking the samples as compared to those with three or less treatments (P<.01. Conclusion. An indiscriminate use of miconazole, such as that observed among female prostitutes in Costa Rica, results in a reduced susceptibility of vaginal yeasts to miconazole but not to other azoles.

Inter-species protein trafficking endows dodder (Cuscuta pentagona) with a host-specific herbicide-tolerant trait.

Science.gov (United States)

Jiang, Linjian; Qu, Feng; Li, Zhaohu; Doohan, Douglas

2013-06-01

· Besides photosynthates, dodder (Cuscuta spp.) acquires phloem-mobile proteins from host; however, whether this could mediate inter-species phenotype transfer was not demonstrated. Specifically, we test whether phosphinothricin acetyl transferase (PAT) that confers host plant glufosinate herbicide tolerance traffics and functions inter-specifically. · Dodder tendrils excised from hosts can grow in vitro for weeks or resume in vivo by parasitizing new hosts. The level of PAT in in vivo and in vitro dodder tendrils was quantified by enzyme-linked immunosorbent assay. The glufosinate sensitivity was examined by dipping the distal end of in vivo and in vitro tendrils, growing on or excised from LibertyLink (LL; PAT-transgenic and glufosinate tolerant) and conventional (CN; glufosinate sensitive) soybean hosts, into glufosinate solutions for 5 s. After in vitro tendrils excised from LL hosts reparasitized new CN and LL hosts, the PAT level and the glufosinate sensitivity were also examined. · When growing on LL host, dodder tolerated glufosinate and contained PAT at a level of 0.3% of that encountered in LL soybean leaf. After PAT was largely degraded in dodders, they became glufosinate sensitive. PAT mRNA was not detected by reverse transcription PCR in dodders. · In conclusion, the results indicated that PAT inter-species trafficking confers dodder glufosinate tolerance. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Colonization and antifungals susceptibility patterns of Candida species isolated from hospitalized patients in ICUs and NICUs.

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Zarei Mahmoudabadi, Ali; Rezaei-Matehkolaei, Ali; Navid, Mojgan; Torabizadeh, Mehdi; Mazdarani, Shahnam

2015-07-01

Several studies have shown that there are an increasing in invasive candidiasis during 2-3 last decades. Although, Candida albicans is considered as the most common candidiasis agents, other non-albicans such as C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis were raised as infectious agents. Resistance to fluconazole among non-albicans species is an important problem for clinicians during therapy and prophylaxis. The aim of current study was to detect the Candida species from hospitalized neonatal and children in intensive care units (ICUs) and neonatal intensive care units (NICUs). In addition, the susceptibility of isolated agents were also evaluated against three antifungals. In the present study 298 samples including 98 blood samples, 100 urines and 100 swabs from oral cavity were inoculated on CHROMagar Candida. Initial detection was done according to the coloration colonies on CHROMagar Candida . Morphology on cornmeal agar, germ tube formation and growth at 45°C were confirmed isolates. Amphotericin B, fluconazole and terbinafine (Lamisil) were used for the susceptibility tests using microdilution method. In the present study 21% and 34% of urines and swabs from oral cavity were positive for Candida species, respectively. The most common species was C. albicans (62.5%) followed by C. tropicalis (15.6%), C. glabrata (6.3%) and Candida species (15.6%). Our study indicated that the most tested species of Candida, 70.3% were sensitive to fluconazole at the concentration of ≤8 μg/mL. Whereas 9 (14.1%) of isolates were resistant to amphotericine B at ≥8 μg/mL. This study demonstrates the importance of species identification and antifungals susceptibility testing for hospitalized patients in ICUs and NICUs wards.

Transcriptome analysis of the fungal pathogen Fusarium oxysporum f. sp. medicaginis during colonisation of resistant and susceptible Medicago truncatula hosts identifies differential pathogenicity profiles and novel candidate effectors.

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Thatcher, Louise F; Williams, Angela H; Garg, Gagan; Buck, Sally-Anne G; Singh, Karam B

2016-11-03

Pathogenic members of the Fusarium oxysporum species complex are responsible for vascular wilt disease on many important crops including legumes, where they can be one of the most destructive disease causing necrotrophic fungi. We previously developed a model legume-infecting pathosystem based on the reference legume Medicago truncatula and a pathogenic F. oxysporum forma specialis (f. sp.) medicaginis (Fom). To dissect the molecular pathogenicity arsenal used by this root-infecting pathogen, we sequenced its transcriptome during infection of a susceptible and resistant host accession. High coverage RNA-Seq of Fom infected root samples harvested from susceptible (DZA315) or resistant (A17) M. truncatula seedlings at early or later stages of infection (2 or 7 days post infection (dpi)) and from vegetative (in vitro) samples facilitated the identification of unique and overlapping sets of in planta differentially expressed genes. This included enrichment, particularly in DZA315 in planta up-regulated datasets, for proteins associated with sugar, protein and plant cell wall metabolism, membrane transport, nutrient uptake and oxidative processes. Genes encoding effector-like proteins were identified, including homologues of the F. oxysporum f. sp. lycopersici Secreted In Xylem (SIX) proteins, and several novel candidate effectors based on predicted secretion, small protein size and high in-planta induced expression. The majority of the effector candidates contain no known protein domains but do share high similarity to predicted proteins predominantly from other F. oxysporum ff. spp. as well as other Fusaria (F. solani, F. fujikori, F. verticilloides, F. graminearum and F. pseudograminearum), and from another wilt pathogen of the same class, a Verticillium species. Overall, this suggests these novel effector candidates may play important roles in Fusaria and wilt pathogen virulence. Combining high coverage in planta RNA-Seq with knowledge of fungal pathogenicity

Antifungal susceptibility testing of Candida species isolated from the immunocompromised patients admitted to ten university hospitals in Iran

NARCIS (Netherlands)

Badiee, P.; Badali, H.; Boekhout, T.; Diba, K.; Moghadam, A.G.; Hossaini Nasab, A.; Jafarian, H.; Mohammadi, R.; Mirhendi, H.; Najafzadeh, M.J.; Shamsizadeh, A.; Soltani, J.

2017-01-01

Background Antifungal susceptibility testing is a subject of interest in the field of medical mycology. The aim of the present study were the distributions and antifungal susceptibility patterns of various Candida species isolated from colonized and infected immunocompromised patients admitted to

Dual RNA-seq of the plant pathogen phytophthora ramorum and its tanoak host

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Katherine J. Hayden; Matteo Garbelotto; Brian J. Knaus; Richard C. Cronn; Hardeep Rai; Jessica W. Wright

2014-01-01

Emergent diseases are an ever-increasing threat to forests and forest ecosystems and necessitate the development of research tools for species that often may have few preexisting resources. We sequenced the mRNA expressed by the sudden oak death pathogen Phytophthora ramorum and its most susceptible forest host, tanoak, within the same tissue at two time points after...

Studies on avian malaria in vectors and hosts of encephalitis in Kern County, California. I. Infections in avian hosts

Science.gov (United States)

Herman, C.M.; Reeves, W.C.; McClure, H.E.; French, E.M.; Hammon, W.M.

1954-01-01

An epizoological study of Plasmodium infections in wild birds of Kern County, California, in the years 1946 through 1951 greatly extended knowledge of the occurrence of these parasites and their behavior in nature. Examination of 10,459 blood smears from 8,674 birds representing 73 species resulted in the observation of Plasmodium spp. in 1,094 smears representing 888 individual birds of 27 species. Seven species of Plasmodium were found: relictum, elongatum, hexamerium, nucleophilum, polare, rouxi and vaughani. Plasmodium relictum was by far the most frequently observed species, occurring in at least 79 per cent of the infected birds. Twelve new host species are recorded for this parasite. Sufficient morphological variation was observed to indicate that two strains of this species probably exist in nature. Numerous new host records were made of plasmodia with elongate gametocytes. The finding of parasites believed to be P. rouxi in two new host species represents the first record of the occurrence of this Plasmodium outside of Algeria. Multiple smears were obtained from a number of individual birds over varying time periods. Evidence of prolonged parasitemia was unusual, but some individuals had parasitemia on consecutive months and even for three successive years. In most individuals, parasitemias were of short duration. The inoculation of blood from wild birds into canaries led to the demonstration of many infections not observed on blood smear examination of donors. Use of these two complementary techniques led to more complete host records and a truer picture of the prevalence of infection. Three age classes of birds were studied--nestling, immature (less than 1 year of age) and adult. Parasites were observed in all three groups but infections in the younger individuals were most susceptible to interpretation. As to time of onset, numerous records were obtained of infection in nestling birds. Prevalence rates in immature birds after a single season's exposure

Wild plant species growing closely connected in a subalpine meadow host distinct root-associated bacterial communities

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Kristin Aleklett

2015-02-01

Full Text Available Plant roots are known to harbor large and diverse communities of bacteria. It has been suggested that plant identity can structure these root-associated communities, but few studies have specifically assessed how the composition of root microbiota varies within and between plant species growing under natural conditions. We assessed the community composition of endophytic and epiphytic bacteria through high throughput sequencing using 16S rDNA derived from root tissues collected from a population of a wild, clonal plant (Orange hawkweed–Pilosella aurantiaca as well as two neighboring plant species (Oxeye daisy–Leucanthemum vulgare and Alsike clover–Trifolium hybridum. Our first goal was to determine if plant species growing in close proximity, under similar environmental conditions, still hosted unique root microbiota. Our results showed that plants of different species host distinct bacterial communities in their roots. In terms of community composition, Betaproteobacteria (especially the family Oxalobacteraceae were found to dominate in the root microbiota of L. vulgare and T. hybridum samples, whereas the root microbiota of P. aurantiaca had a more heterogeneous distribution of bacterial abundances where Gammaproteobacteria and Acidobacteria occupied a larger portion of the community. We also explored the extent of individual variance within each plant species investigated, and found that in the plant species thought to have the least genetic variance among individuals (P. aurantiaca still hosted just as diverse microbial communities. Whether all plant species host their own distinct root microbiota and plants more closely related to each other share more similar bacterial communities still remains to be fully explored, but among the plants examined in this experiment there was no trend that the two species belonging to the same family shared more similarities in terms of bacterial community composition.

The susceptibility of Asian, European and North American Fraxinus species to the ash dieback pathogen Hymenoscyphus fraxineus reflects their phylogenetic history

DEFF Research Database (Denmark)

Nielsen, Lene Rostgaard; McKinney, Lea Vig; Hietala, Ari M.

2017-01-01

susceptibility where closely related Asian, European and North American species in section Fraxinus had relatively high levels of H. fraxineus DNA in the leaves and supported high production of apothecia. Leaves from some North American species also contained relatively high levels of H. fraxineus DNA, supported...... that there is species-specific variation in disease susceptibility among European and North American Fraxinus species, but a wider comparison at the genus level has been missing so far. We assessed disease symptoms and pathogen apothecium development in 17 Fraxinus species from Asia, Europe and North America exposed...

Susceptibility of Several Northeastern Conifers to Fusarium circinatum and Strategies for Biocontrol

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Jorge Martín-García

2017-08-01

Full Text Available Fusarium circinatum, the causal of pine pitch canker disease (PPC, is now considered among the most important pathogens of Pinaceae in the world. Although in Europe PPC is only established in the Iberian Peninsula, the potential endangered areas cover over 10 million hectares under the current host distribution and climatic conditions. It is therefore a priority to test the susceptibility of those species and their provenances, within Central and Northern Europe and find biological control agents (BCAs against the disease. In this study, the susceptibility of Pinus sylvestris, P. mugo and Picea abies Romanian provenances to F. circinatum was tested using three inoculum doses. In parallel, the potential use of Trichoderma atroviride and Trichoderma viride as BCAs against F. circinatum was also tested. This study has demonstrated, for the first time, the susceptibility of P. mugo to F. circinatum. Likewise, the susceptibility of P. abies was also confirmed. The fact that the Romanian provenance of P. sylvestris has not been susceptible to F. circinatum suggests genetic resistance as a potential tool to manage the disease. This, together with the apparent effectiveness of Trichoderma species as BCAs, seems to indicate that an integrated management of the disease might be feasible.

Antibiotic Susceptibility Profile of Aeromonas Species Isolated from Wastewater Treatment Plant

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Isoken H. Igbinosa

2012-01-01

Full Text Available This study assessed the prevalence of antibiotic-resistant Aeromonas species isolated from Alice and Fort Beaufort wastewater treatment plant in the Eastern Cape Province of South Africa. Antibiotic susceptibility was determined using the disc diffusion method, and polymerase chain reaction (PCR assay was employed for the detection of antibiotics resistance genes. Variable susceptibilities were observed against ciprofloxacin, chloramphenicol, nalidixic acid, gentamicin, minocycline, among others. Aeromonas isolates from both locations were 100% resistant to penicillin, oxacillin, ampicillin, and vancomycin. Higher phenotypic resistance was observed in isolates from Fort Beaufort compared to isolates from Alice. Class A pse1 β-lactamase was detected in 20.8% of the isolates with a lower detection rate of 8.3% for blaTEM gene. Class 1 integron was present in 20.8% of Aeromonas isolates while class 2 integron and TetC gene were not detected in any isolate. The antibiotic resistance phenotypes observed in the isolates and the presence of β-lactamases genes detected in some isolates are of clinical and public health concern as this has consequences for antimicrobial chemotherapy of infections associated with Aeromonas species. This study further supports wastewater as potential reservoirs of antibiotic resistance determinants in the environment.

Low susceptibility of invasive red lionfish (Pterois volitans) to a generalist ectoparasite in both its introduced and native ranges.

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Sikkel, Paul C; Tuttle, Lillian J; Cure, Katherine; Coile, Ann Marie; Hixon, Mark A

2014-01-01

Escape from parasites in their native range is one of many mechanisms that can contribute to the success of an invasive species. Gnathiid isopods are blood-feeding ectoparasites that infest a wide range of fish hosts, mostly in coral reef habitats. They are ecologically similar to terrestrial ticks, with the ability to transmit blood-borne parasites and cause damage or even death to heavily infected hosts. Therefore, being highly resistant or highly susceptible to gnathiids can have significant fitness consequences for reef-associated fishes. Indo-Pacific red lionfish (Pterois volitans) have invaded coastal habitats of the western tropical and subtropical Atlantic and Caribbean regions. We assessed the susceptibility of red lionfish to parasitic gnathiid isopods in both their native Pacific and introduced Atlantic ranges via experimental field studies during which lionfish and other, ecologically-similar reef fishes were caged and exposed to gnathiid infestation on shallow coral reefs. Lionfish in both ranges had very few gnathiids when compared with other species, suggesting that lionfish are not highly susceptible to infestation by generalist ectoparasitic gnathiids. While this pattern implies that release from gnathiid infestation is unlikely to contribute to the success of lionfish as invaders, it does suggest that in environments with high gnathiid densities, lionfish may have an advantage over species that are more susceptible to gnathiids. Also, because lionfish are not completely resistant to gnathiids, our results suggest that lionfish could possibly have transported blood parasites between their native Pacific and invaded Atlantic ranges.

Epidemiology and susceptibility to antimicrobial agents of the main Nocardia species in Spain.

Science.gov (United States)

Valdezate, Sylvia; Garrido, Noelia; Carrasco, Gema; Medina-Pascual, María J; Villalón, Pilar; Navarro, Ana M; Saéz-Nieto, Juan A

2017-03-01

The aims of this study were to explore the clinical distribution, by species, of the genus Nocardia and to assess the antimicrobial susceptibilities of the 10 most prevalent species identified in Spain. Over a 10 year period (2005-14), 1119 Nocardia strains were molecularly identified and subjected to the Etest. The distribution and resistance trends over the sub-periods 2005-09 and 2010-14 were also examined. Of the strains examined, 82.9% belonged to the following species: Nocardia cyriacigeorgica (25.3%), Nocardia nova (15.0%), Nocardia abscessus (12.7%), Nocardia farcinica (11.4%), Nocardia carnea (4.3%), Nocardia brasiliensis (3.5%), Nocardia otitidiscaviarum (3.1%), Nocardia flavorosea (2.6%), Nocardia rhamnosiphila (2.6%) and Nocardia transvalensis (2.4%). Their prevalence values were similar during 2005-09 and 2010-14, except for those of N. abscessus , N. farcinica and N. transvalensis , which fell significantly in the second sub-period ( P ≤  0.05). The major location of isolation was the respiratory tract (∼86%). Half (13/27) of all strains from the CNS were N. farcinica . Significant differences in MIC results were recorded for some species between the two sub-periods. According to the CLSI's breakpoints, low resistance rates (≤15%) were recorded for seven species with respect to cefotaxime, imipenem and tobramycin; five species showed similar rates with respect to trimethoprim/sulfamethoxazole. Linezolid and amikacin were the most frequently active agents. The accurate identification of the infecting species and the determination of its susceptibility to antimicrobial agents, given the large number of strains with atypical patterns, are crucial if patients with nocardiosis are to be successfully treated. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Host density and competency determine the effects of host diversity on trematode parasite infection.

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Jeremy M Wojdak

Full Text Available Variation in host species composition can dramatically alter parasite transmission in natural communities. Whether diverse host communities dilute or amplify parasite transmission is thought to depend critically on species traits, particularly on how hosts affect each other's densities, and their relative competency as hosts. Here we studied a community of potential hosts and/or decoys (i.e. non-competent hosts for two trematode parasite species, Echinostoma trivolvis and Ribeiroia ondatrae, which commonly infect wildlife across North America. We manipulated the density of a focal host (green frog tadpoles, Rana clamitans, in concert with manipulating the diversity of alternative species, to simulate communities where alternative species either (1 replace the focal host species so that the total number of individuals remains constant (substitution or (2 add to total host density (addition. For E. trivolvis, we found that total parasite transmission remained roughly equal (or perhaps decreased slightly when alternative species replaced focal host individuals, but parasite transmission was higher when alternative species were added to a community without replacing focal host individuals. Given the alternative species were roughly equal in competency, these results are consistent with current theory. Remarkably, both total tadpole and per-capita tadpole infection intensity by E. trivolvis increased with increasing intraspecific host density. For R. ondatrae, alternative species did not function as effective decoys or hosts for parasite infective stages, and the diversity and density treatments did not produce clear changes in parasite transmission, although high tank to tank variation in R. ondatrae infection could have obscured patterns.

Host age modulates within-host parasite competition.

Science.gov (United States)

Izhar, Rony; Routtu, Jarkko; Ben-Ami, Frida

2015-05-01

In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa, we examined how host age at exposure influences within-host parasite competition and virulence. We found that multiply-exposed hosts were more susceptible to infection and suffered higher mortality than singly-exposed hosts. Hosts oldest at exposure were least often infected and vice versa. Furthermore, we found that in young multiply-exposed hosts competition was weak, allowing coexistence and transmission of both parasite clones, whereas in older multiply-exposed hosts competitive exclusion was observed. Thus, age-dependent parasite exposure and host demography (age structure) could together play an important role in mediating parasite evolution. At the individual level, our results demonstrate a previously unnoticed interaction of the host's immune system with host age, suggesting that the specificity of immune function changes as hosts mature. Therefore, evolutionary models of parasite virulence might benefit from incorporating age-dependent epidemiological parameters. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Toxocara cati (Schrank, 1788 (Nematoda, Ascarididae in different wild feline species in Brazil: new host records

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Moisés Gallas

2013-09-01

Full Text Available This is the first detailed description of Toxocara cati parasitizing felines in South America. Seventeen run over wild felines (Leopardus colocolo, Leopardus geoffroyi, Leopardus tigrinus, and Puma yagouaroundi were collected from different towns in the State of Rio Grande do Sul, Brazil. The morphometry of males and females allowed the identification of specimens as being T. cati. The helminths were found in the stomach and intestine of hosts with prevalences of 66.6% in L. colocolo, L. geoffroyi, and L. tigrinus; and 60% in P. yagouaroundi. The ecological parameters were calculated for each host and L. colocolo had the highest infection intensity (22.5 helminths/host. This is the first report of T. cati parasitizing four wild felines species in southern Brazil, besides a new record of this parasite for two host species.

Anastrepha species (Diptera: Tephritidae, their host plants and parasitoids (Hymenoptera in the state of Roraima, Brazil: state of the art

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Alberto Luiz Marsaro Júnior

2017-02-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2017v30n1p13 The aim of this review was to update the available information on Anastrepha species in the state of Roraima, Brazil, with emphasis on distribution, host plants and parasitoids. In total, 25 species of Anastrepha and 27 host plant species have been recorded to date in Roraima. Anastrepha striata and A. obliqua are widely distributed in the state. Anastrepha obliqua is the most polyphagous species, where it is associated with 13 hosts. Six species of parasitoids of Anastrepha have been reported in Roraima. Of these, Doryctobracon areolatus is the most abundant and has been associated with the largest number of Anastrepha species.

Multi locus sequence typing of Chlamydia reveals an association between Chlamydia psittaci genotypes and host species.

Science.gov (United States)

Pannekoek, Yvonne; Dickx, Veerle; Beeckman, Delphine S A; Jolley, Keith A; Keijzers, Wendy C; Vretou, Evangelia; Maiden, Martin C J; Vanrompay, Daisy; van der Ende, Arie

2010-12-02

Chlamydia comprises a group of obligate intracellular bacterial parasites responsible for a variety of diseases in humans and animals, including several zoonoses. Chlamydia trachomatis causes diseases such as trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. Chlamydia pneumoniae is a common cause of community-acquired respiratory tract infections. Chlamydia psittaci, causing zoonotic pneumonia in humans, is usually hosted by birds, while Chlamydia abortus, causing abortion and fetal death in mammals, including humans, is mainly hosted by goats and sheep. We used multi-locus sequence typing to asses the population structure of Chlamydia. In total, 132 Chlamydia isolates were analyzed, including 60 C. trachomatis, 18 C. pneumoniae, 16 C. abortus, 34 C. psittaci and one of each of C. pecorum, C. caviae, C. muridarum and C. felis. Cluster analyses utilizing the Neighbour-Joining algorithm with the maximum composite likelihood model of concatenated sequences of 7 housekeeping fragments showed that C. psittaci 84/2334 isolated from a parrot grouped together with the C. abortus isolates from goats and sheep. Cluster analyses of the individual alleles showed that in all instances C. psittaci 84/2334 formed one group with C. abortus. Moving 84/2334 from the C. psittaci group to the C. abortus group resulted in a significant increase in the number of fixed differences and elimination of the number of shared mutations between C. psittaci and C. abortus. C. psittaci M56 from a muskrat branched separately from the main group of C. psittaci isolates. C. psittaci genotypes appeared to be associated with host species. The phylogenetic tree of C. psittaci did not follow that of its host bird species, suggesting host species jumps. In conclusion, we report for the first time an association between C. psittaci genotypes with host species.

Multi locus sequence typing of Chlamydia reveals an association between Chlamydia psittaci genotypes and host species.

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Yvonne Pannekoek

2010-12-01

Full Text Available Chlamydia comprises a group of obligate intracellular bacterial parasites responsible for a variety of diseases in humans and animals, including several zoonoses. Chlamydia trachomatis causes diseases such as trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. Chlamydia pneumoniae is a common cause of community-acquired respiratory tract infections. Chlamydia psittaci, causing zoonotic pneumonia in humans, is usually hosted by birds, while Chlamydia abortus, causing abortion and fetal death in mammals, including humans, is mainly hosted by goats and sheep. We used multi-locus sequence typing to asses the population structure of Chlamydia. In total, 132 Chlamydia isolates were analyzed, including 60 C. trachomatis, 18 C. pneumoniae, 16 C. abortus, 34 C. psittaci and one of each of C. pecorum, C. caviae, C. muridarum and C. felis. Cluster analyses utilizing the Neighbour-Joining algorithm with the maximum composite likelihood model of concatenated sequences of 7 housekeeping fragments showed that C. psittaci 84/2334 isolated from a parrot grouped together with the C. abortus isolates from goats and sheep. Cluster analyses of the individual alleles showed that in all instances C. psittaci 84/2334 formed one group with C. abortus. Moving 84/2334 from the C. psittaci group to the C. abortus group resulted in a significant increase in the number of fixed differences and elimination of the number of shared mutations between C. psittaci and C. abortus. C. psittaci M56 from a muskrat branched separately from the main group of C. psittaci isolates. C. psittaci genotypes appeared to be associated with host species. The phylogenetic tree of C. psittaci did not follow that of its host bird species, suggesting host species jumps. In conclusion, we report for the first time an association between C. psittaci genotypes with host species.

Species distribution and antifungal susceptibility of Candida spp. isolated from superficial candidiasis in outpatients in Iran.

Science.gov (United States)

Razzaghi-Abyaneh, M; Sadeghi, G; Zeinali, E; Alirezaee, M; Shams-Ghahfarokhi, M; Amani, A; Mirahmadi, R; Tolouei, R

2014-06-01

Candidiasis is the most prevalent fungal infection affecting human and animals all over the world. This study represents the epidemiological aspects of superficial candidiasis in outpatients and in vitro antifungal susceptibility of etiologic Candida species. Clinical samples were taken from 173 patients including skin and nail scrapings (107; 61.8%), vaginal discharge (28; 16.2%), sputum (20; 11.6%), oral swabs (7; 4.0%), bronchoalveolar lavage (6; 3.5%) and 1 specimen (0.6%) of each eye tumor, gastric juice, urine, biopsy and urinary catheter and confirmed as candidiasis by direct microscopy, culture and histopathology. Susceptibility patterns of the isolated Candida species were determined using the disk diffusion and broth microdilution methods. Among 173 Candida isolates, C. albicans (72.3%) was the most prevalent species followed by C. parapsilosis (11.5%). Other identified species were C. glabrata, C. krusei, C. tropicalis, C. guilliermondii, C. intermedia and C. sake. Majority of the Candida isolates were susceptible to fluconazole (95.4%) followed by 5-flucytosine (89.6%), voriconazole (78.6%) itraconazole (48.0%) and ketoconazole (42.8%). Caspofungin was the most potent antifungal drug against C. albicans (MICs; 0.062-1 μg/mL), ketoconazole for C. parapsilosis and C. tropicalis (MICs; 0.031-0.25 μg/mL) and itraconazole for C. krusei, C. glabrata and C. guilliermondii (MICs; 0.031-1 μg/mL). This study reinforces the significance of superficial candidiasis as an important fungal infection with multiple clinical presentations. Our results further indicate that susceptibility testing to commonly used antifungals is crucial in order to select the appropriate therapeutic strategies which minimize complications while improving patients' life. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Contrasting Plasticity in Ovariole Number Induced by A Dietary Effect of the Host Plants between Cactophilic Drosophila Species

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Daniela Peluso

2016-05-01

Full Text Available Under the preference-performance hypothesis, natural selection will favor females that choose oviposition sites that optimize the fitness of their offspring. Such a preference-performance relationship may entail important consequences mainly on fitness-related traits. We used the well-characterized cactus-Drosophila system to investigate the reproductive capacity in the pair of sibling species D. buzzatii and D. koepferae reared in two alternative host plants. According to our hypothesis, ovariole number (as a proxy of reproductive capacity depends on host plant selection. Our results indicate that the capacity of D. buzzatii showed to be mild, only increasing the number of ovarioles by as much as 10% when reared in its preferred host. In contrast, D. koepferae exhibited a similar reproductive capacity across host cacti, even though it showed a preference for its primary host cactus. Our study also revealed that D. buzzatii has a larger genetic variation for phenotypic plasticity than its sibling, although ovariole number did not show clear-cut differences between species. We will discuss the weak preference-performance pattern observed in these cactophilic species in the light of nutritional and toxicological differences found between the natural host plants.

Genetic diversity and antifungal susceptibility of Fusarium isolates in onychomycosis.

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Rosa, Priscila D; Heidrich, Daiane; Corrêa, Carolina; Scroferneker, Maria Lúcia; Vettorato, Gerson; Fuentefria, Alexandre M; Goldani, Luciano Z

2017-09-01

Fusarium species have emerged as an important human pathogen in skin disease, onychomycosis, keratitis and invasive disease. Onychomycosis caused by Fusarium spp. The infection has been increasingly described in the immunocompetent and immunosuppressed hosts. Considering onychomycosis is a difficult to treat infection, and little is known about the genetic variability and susceptibility pattern of Fusarium spp., further studies are necessary to understand the pathogenesis and better to define the appropriate antifungal treatment for this infection. Accordingly, the objective of this study was to describe the in vitro susceptibility to different antifungal agents and the genetic diversity of 35 Fusarium isolated from patients with onychomycosis. Fusarium spp. were isolated predominantly from female Caucasians, and the most frequent anatomical location was the nail of the hallux. Results revealed that 25 (71.4%) of isolates belonged to the Fusarium solani species complex, followed by 10 (28.5%) isolates from the Fusarium oxysporum species complex. Noteworthy, the authors report the first case of Neocosmospora rubicola isolated from a patient with onychomycosis. Amphotericin B was the most effective antifungal agent against the majority of isolates (60%, MIC ≤4 μg/mL), followed by voriconazole (34.2%, MIC ≤4 μg/mL). In general, Fusarium species presented MIC values >64 μg/mL for fluconazole, itraconazole and terbinafine. Accurate pathogen identification, characterisation and susceptibility testing provide a better understanding of pathogenesis of Fusarium in onychomycosis. © 2017 Blackwell Verlag GmbH.

Candidal colonization, strain diversity, and antifungal susceptibility among adult diabetic patients.

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Al-Attas, Safia A; Amro, Soliman O

2010-01-01

Candidal colonization in diabetics is a matter of debate. The aim of this study is to investigate oral candidal colonization, strain diversity, antifungal susceptibility, and the influence of local and systemic host factors on candidal colonization in adult diabetics. We conducted a case-control study that compared 150 diabetics (49 type 1, 101 type 2) with 50 healthy controls. Two salivary samples were collected, using the oral rinse sampling method: one for salivary flow rate and pH determination, and the other for candidal colonization assessment. The candidal isolates were identified and tested in vitro for antifungal susceptibility using the commercial kit, Candifast. The relationship between specific host factors and candidal colonization was also investigated. Diabetics had a higher candidal carriage rate compared to controls, but not density. Candida albicans was the most frequently isolated species, but diabetics had a variety of other candidal species present. None of the control samples were resistant to any tested antifungal, while the diabetic samples had differing resistances to azole antifungals. Although there was a significant positive correlation between glycemic control and candidal colonization in type 2 diabetics, there was a negative correlation between salivary pH and candidal carriage in the controls versus density in type 2 diabetics. Diabetic patients not only had a higher candidal carriage rate, but also a variety of candidal species that were resistant to azole antifungals. Oral candidal colonization was significantly associated with glycemic control, type of diabetes, and salivary pH.

Caterpillars and host plant records for 59 species of Geometridae (Lepidoptera) from a montane rainforest in southern Ecuador.

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Bodner, Florian; Brehm, Gunnar; Homeier, Jürgen; Strutzenberger, Patrick; Fiedler, Konrad

2010-01-01

During four months of field surveys at the Reserva Biológica San Francisco in the south Ecuadorian Andes, caterpillars of 59 Geometridae species were collected in a montane rainforest between 1800 and 2800m altitude and reared to adults. The resulting data on host plant affiliations of these species was collated. The preimaginal stages of 58 and adult stages of all 59 species are depicted in colour plates. Observations on morphology and behaviour are briefly described. Five species, documented for the first time in the study area by means of larval collections, had not been previously collected by intensive light-trap surveys. Together with published literature records, life-history data covers 8.6% of the 1271 geometrid species observed so far in the study area. For 50 species these are the first records of their early stages, and for another 7 the data significantly extend known host plant ranges. Most larvae were collected on shrubs or trees, but more unusual host plant affiliations, such as ferns (6 geometrid species) and lichens (3 geometrid species), were also recorded. Thirty-four percent of the caterpillars were infested by wasp or tachinid parasitoids.

Host-related genetic differentiation in the anther smut fungus Microbotryum violaceum in sympatric, parapatric and allopatric populations of two host species Silene latifolia and S. dioica

NARCIS (Netherlands)

Van Putten, W.F.; Biere, A.; Van Damme, J.M.M.

2005-01-01

We investigated genetic diversity in West European populations of the fungal pathogen Microbotryum violaceum in sympatric, parapatric and allopatric populations of the host species Silene latifolia and S. dioica, using four polymorphic microsatellite loci. In allopatric host populations, the fungus

Host-related genetic differentiation in the anther smut fungus Microbotryum violaceum in sympatric, parapatric and allopatric populations of two host species Silene latifolia and S-dioica

NARCIS (Netherlands)

Van Putten, WF; Biere, A; Van Damme, JMM

We investigated genetic diversity in West European populations of the fungal pathogen Microbotryum violaceum in sympatric, parapatric and allopatric populations of the host species Silene latifolia and S. dioica, using four polymorphic microsatellite loci. In allopatric host populations, the fungus

Bat lung epithelial cells show greater host species-specific innate resistance than MDCK cells to human and avian influenza viruses.

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Slater, Tessa; Eckerle, Isabella; Chang, Kin-Chow

2018-04-10

With the recent discovery of novel H17N10 and H18N11 influenza viral RNA in bats and report on high frequency of avian H9 seroconversion in a species of free ranging bats, an important issue to address is the extent bats are susceptible to conventional avian and human influenza A viruses. To this end, three bat species (Eidolon helvum, Carollia perspicillata and Tadarida brasiliensis) of lung epithelial cells were separately infected with two avian and two human influenza viruses to determine their relative host innate immune resistance to infection. All three species of bat cells were more resistant than positive control Madin-Darby canine kidney (MDCK) cells to all four influenza viruses. TB1-Lu cells lacked sialic acid α2,6-Gal receptors and were most resistant among the three bat species. Interestingly, avian viruses were relatively more replication permissive in all three bat species of cells than with the use of human viruses which suggest that bats could potentially play a role in the ecology of avian influenza viruses. Chemical inhibition of the JAK-STAT pathway in bat cells had no effect on virus production suggesting that type I interferon signalling is not a major factor in resisting influenza virus infection. Although all three species of bat cells are relatively more resistant to influenza virus infection than control MDCK cells, they are more permissive to avian than human viruses which suggest that bats could have a contributory role in the ecology of avian influenza viruses.

Variation in the susceptibility of Drosophila to different entomopathogenic nematodes.

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Peña, Jennifer M; Carrillo, Mayra A; Hallem, Elissa A

2015-03-01

Entomopathogenic nematodes (EPNs) in the genera Heterorhabditis and Steinernema are lethal parasites of insects that are of interest as models for understanding parasite-host interactions and as biocontrol agents for insect pests. EPNs harbor a bacterial endosymbiont in their gut that assists in insect killing. EPNs are capable of infecting and killing a wide range of insects, yet how the nematodes and their bacterial endosymbionts interact with the insect immune system is poorly understood. Here, we develop a versatile model system for understanding the insect immune response to parasitic nematode infection that consists of seven species of EPNs as model parasites and five species of Drosophila fruit flies as model hosts. We show that the EPN Steinernema carpocapsae, which is widely used for insect control, is capable of infecting and killing D. melanogaster larvae. S. carpocapsae is associated with the bacterium Xenorhabdus nematophila, and we show that X. nematophila induces expression of a subset of antimicrobial peptide genes and suppresses the melanization response to the nematode. We further show that EPNs vary in their virulence toward D. melanogaster and that Drosophila species vary in their susceptibilities to EPN infection. Differences in virulence among different EPN-host combinations result from differences in both rates of infection and rates of postinfection survival. Our results establish a powerful model system for understanding mechanisms of host-parasite interactions and the insect immune response to parasitic nematode infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Antimicrobial Susceptibility Patterns Of Salmonella Species In ...

African Journals Online (AJOL)

% susceptible to cefepime and carbapenem, 91% to azithromycin, 82.1% to cefixime and 73% to quinolones. Also susceptibility to chloramphenicol, erythromycin, streptomycin, ampicillin, gentamicin, co-trimoxazole, augmentin and amikacin ...

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

Diversity, distribution and host-species associations of epiphytic orchids in Nepal

Czech Academy of Sciences Publication Activity Database

Timsina, Binu; Rokaya, Maan Bahadur; Munzbergová, Z.; Kindlmann, Pavel; Shrestha, B.; Bhattarai, Bishnu Prasad; Raskoti, B. B.

2016-01-01

Roč. 25, č. 13 (2016), s. 2803-2819 ISSN 0960-3115 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : vascular epiphytes * vertical stratification * elevational gradients * kathmandu valley * tree utilization * forest * richness * mexico * conservation * abundance * Species richness * Composition * Host * Traits * Nepal Himalaya Subject RIV: EF - Botanics Impact factor: 2.265, year: 2016

Dispersal limitation of Tillandsia species correlates with rain and host structure in a central Mexican tropical dry forest.

Science.gov (United States)

Victoriano-Romero, Elizabeth; Valencia-Díaz, Susana; Toledo-Hernández, Víctor Hugo; Flores-Palacios, Alejandro

2017-01-01

Seed dispersal permits the colonization of favorable habitats and generation of new populations, facilitating escape from habitats that are in decline. There is little experimental evidence of the factors that limit epiphyte dispersion towards their hosts. In a tropical dry forest in central Mexico, we monitored the phenology of dispersion of epiphyte species of the genus Tillandsia; we tested experimentally whether precipitation could cause failures in seed dispersal and whether seed capture differs among vertical strata and between host species with high (Bursera copallifera) and low (Conzattia multiflora) epiphyte loads. With the exception of one species that presents late dispersion and low abundance, all of the species disperse prior to the onset of the rainy season. However, early rains immobilize the seeds, affecting up to 24% of the fruits in species with late dispersion. We observed that Tillandsia seeds reach both Bursera and Conzattia hosts, but found that adherence to the host is 4-5 times higher in Bursera. Furthermore, seeds liberated from Bursera travel shorter distances and up to half may remain within the same crown, while the highest seed capture takes place in the upper strata of the trees. We conclude that dispersion of Tillandsia seeds is limited by early rains and by the capture of seeds within the trees where populations concentrate. This pattern of capture also helps to explain the high concentrations of epiphytes in certain hosts, while trees with few epiphytes can be simultaneously considered deficient receivers and efficient exporters of seeds.

A comparative analysis of genetic differentiation across six shared willow host species in leaf- and bud-galling sawflies.

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Sanna A Leppänen

Full Text Available Genetic divergence and speciation in plant-feeding insects could be driven by contrasting selection pressures imposed by different plant species and taxa. While numerous examples of host-associated differentiation (HAD have been found, the overall importance of HAD in insect diversification remains unclear, as few studies have investigated its frequency in relation to all speciation events. One promising way to infer the prevalence and repeatability of HAD is to estimate genetic differentiation in multiple insect taxa that use the same set of hosts. To this end, we measured and compared variation in mitochondrial COI and nuclear ITS2 sequences in population samples of leaf-galling Pontania and bud-galling Euura sawflies (Hymenoptera: Tenthredinidae collected from six Salix species in two replicate locations in northern Fennoscandia. We found evidence of frequent HAD in both species complexes, as individuals from the same willow species tended to cluster together on both mitochondrial and nuclear phylogenetic trees. Although few fixed differences among the putative species were found, hierarchical AMOVAs showed that most of the genetic variation in the samples was explained by host species rather than by sampling location. Nevertheless, the levels of HAD measured across specific pairs of host species were not correlated in the two focal galler groups. Hence, our results support the hypothesis of HAD as a central force in herbivore speciation, but also indicate that evolutionary trajectories are only weakly repeatable even in temporally overlapping radiations of related insect taxa.

In vitro susceptibility patterns of clinically important Trichophyton and Epidermophyton species against nine antifungal drugs

NARCIS (Netherlands)

Badali, Hamid; Mohammadi, Rasoul; Mashedi, Olga; de Hoog, G Sybren; Meis, Jacques F

Despite the common, worldwide, occurrence of dermatophytes, little information is available regarding susceptibility profiles against currently available and novel antifungal agents. A collection of sixty-eight clinical Trichophyton species and Epidermophyton floccosum were previously identified and

Antibiotic susceptibility profiles for mastitis treatment.

Science.gov (United States)

Hinckley, L S; Benson, R H; Post, J E; DeCloux, J C

1985-10-01

Susceptibility tests were performed on milk samples representing prevalent mastitis infections in certain herds. Susceptibility patterns of the same bacterial species from several mastitis infections in the same herd were consistent. The herd antibiotic susceptibility profiles were used as a basis for selecting antibiotics for treatment of all such mastitis cases in that herd. A high degree of correlation was seen between the susceptibility test results and treatment results. Susceptibility patterns of the same bacterial species from mastitis infections in different herds varied greatly, which indicated that any one antibiotic would not work equally well against the same bacterial infection in every herd. Therefore, treatment should be selected on the basis of susceptibility test results. When both Streptococcus and Staphylococcus mastitis occurred in the same herd, the susceptibility patterns for the 2 bacterial species varied widely. Therefore, for herds that experienced both streptococcal and staphylococcal mastitis, antibiotics to which both bacterial species were susceptible were used for treatment.

Is induction ability of seed germination of Phelipanche ramosa phylogenetically structured among hosts? A case study on Fabaceae species.

Science.gov (United States)

Perronne, Rémi; Gibot-Leclerc, Stéphanie; Dessaint, Fabrice; Reibel, Carole; Le Corre, Valérie

2017-12-01

Phelipanche ramosa is a major root-holoparasitic damaging weed characterized by a broad host range, including numerous Fabaceae species. In France, the agricultural threat posed by P. ramosa has increased over two decades due to the appearance of a genetically differentiated pathovar presenting a clear host specificity for oilseed rape. The new pathovar has led to a massive expansion of P. ramosa in oilseed rape fields. The germination rate of P. ramosa seeds is currently known to vary among P. ramosa pathovars and host species. However, only a few studies have investigated whether phylogenetic relatedness among potential host species is a predictor of the ability of these species to induce the seed germination of parasitic weeds by testing for phylogenetic signal. We focused on a set of 12 Fabaceae species and we assessed the rate of induction of seed germination by these species for two pathovars based on in vitro co-cultivation experiments. All Fabaceae species tested induced the germination of P. ramosa seeds. The germination rate of P. ramosa seeds varied between Fabaceae species and tribes studied, while pathovars appeared non-influential. Considering oilseed rape as a reference species, we also highlighted a significant phylogenetic signal. Phylogenetically related species therefore showed more similar rates of induction of seed germination than species drawn at random from a phylogenetic tree. In in vitro conditions, only Lotus corniculatus induced a significantly higher germination rate than oilseed rape, and could potentially be used as a catch crop after confirmation of these results under field conditions.

Molecular and morphological analysis reveals five new species of Zygophiala associated with flyspeck signs on plant hosts from China.

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Liu Gao

Full Text Available Species in the genus Zygophiala are associated with sooty blotch and flyspeck disease on a wide range of hosts. In this study, 63 Zygophiala isolates collected from flyspeck colonies on a range of plants from several regions of China were used for phylogeny, host range and geographic distribution analysis. Phylogenetic trees were constructed on four genes--internal transcribed spacer (ITS, partial translation elongation factor 1-alpha (TEF, β-tubulin (TUB2, and actin (ACT--both individually and in combination. Isolates were grouped into 11 clades among which five new species, Z. emperorae, Z. trispora, Z. musae, Z. inaequalis and Z. longispora, were described. Species of Zygophiala differed in observed host range and geographic distribution. Z. wisconsinensis and Z. emperorae were the most prevalent throughout the sampled regions of China, whereas Z. trispora, Z. musae, Z. inaequalis and Z. longispora were collected only in southern China. The hosts of Z. wisconsinensis and Z. emperorae were mainly in the family Rosaceae whereas Z. trispora, Z. musae, Z. inaequalis and Z. longispora were found mainly on banana (Musa spp.. Cross inoculation tests provided evidence of host specificity among SBFS species.

Effects of phylogeny, leaf traits, and the altitudinal distribution of host plants on herbivore assemblages on congeneric Acer species.

Science.gov (United States)

Nakadai, Ryosuke; Murakami, Masashi; Hirao, Toshihide

2014-08-01

Historical, niche-based, and stochastic processes have been proposed as the mechanisms that drive community assembly. In plant-herbivore systems, these processes can correspond to phylogeny, leaf traits, and the distribution of host plants, respectively. Although patterns of herbivore assemblages among plant species have been repeatedly examined, the effects of these factors among co-occurring congeneric host plant species have rarely been studied. Our aim was to reveal the process of community assembly for herbivores by investigating the effects of phylogeny, leaf traits, and the altitudinal distribution of closely related host plants of the genus Acer. We sampled leaf functional traits for 30 Acer species in Japan. Using a newly constructed phylogeny, we determined that three of the six measured leaf traits (leaf thickness, C/N ratio, and condensed tannin content) showed a phylogenetic signal. In a field study, we sampled herbivore communities on 14 Acer species within an elevation gradient and examined relationships between herbivore assemblages and host plants. We found that herbivore assemblages were significantly correlated with phylogeny, leaf traits, phylogenetic signals, and the altitudinal distribution of host plants. Our results indicate that the interaction between historical and current ecological processes shapes herbivore community assemblages.

Molecular identification and antifungal susceptibility profile of Candida species isolated from patients with vulvovaginitis in Tehran, Iran.

Science.gov (United States)

Sharifynia, Somayeh; Falahati, Mehraban; Akhlaghi, Lame; Foroumadi, Alireza; Fateh, Roohollah

2017-01-01

Rapid and accurate identification and evaluation of antifungal susceptibility pattern of Candida isolates are crucial to determine suitable antifungal drugs for the treatment of patients with vulvovaginitis candidiasis. Vaginal samples were collected from 150 women with suspicious vaginal candidiasis, and then cultured on Sabouraoud's Dextrose Agar with chloramphenicol to isolate Candida species. After identification of Candida isolates using polymerase chain reaction-restriction fragment length polymorphism technique, antifungal susceptibility testing of four azolic antifungal drugs was carried out using broth microdilution method according to the CLSI M27-A3. Candida species were isolated from eighty suspected patients (61.79%). The most common pathogen was Candida albicans (63.75%). Resistance to fluconazole and ketoconazole was observed in 27.5% and 23.75% of Candida isolates, respectively, and only 2% of Candida isolates were resistant to miconazole. Interestingly, resistance to fluconazole in C. albicans was more than other Candida species. The results indicated that therapy should be selected according to the antifungal susceptibility tests for the prevention of treatment failure and miconazole therapy can be considered as the best therapeutic choice in the management of vulvovaginitis.

Molecular identification and antifungal susceptibility profile of Candida species isolated from patients with vulvovaginitis in Tehran, Iran

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Somayeh Sharifynia

2017-01-01

Full Text Available Background: Rapid and accurate identification and evaluation of antifungal susceptibility pattern of Candida isolates are crucial to determine suitable antifungal drugs for the treatment of patients with vulvovaginitis candidiasis. Materials and Methods: Vaginal samples were collected from 150 women with suspicious vaginal candidiasis, and then cultured on Sabouraoud's Dextrose Agar with chloramphenicol to isolate Candida species. After identification of Candida isolates using polymerase chain reaction-restriction fragment length polymorphism technique, antifungal susceptibility testing of four azolic antifungal drugs was carried out using broth microdilution method according to the CLSI M27-A3. Results: Candida species were isolated from eighty suspected patients (61.79%. The most common pathogen was Candida albicans (63.75%. Resistance to fluconazole and ketoconazole was observed in 27.5% and 23.75% of Candida isolates, respectively, and only 2% of Candida isolates were resistant to miconazole. Interestingly, resistance to fluconazole in C. albicans was more than other Candida species. Conclusion: The results indicated that therapy should be selected according to the antifungal susceptibility tests for the prevention of treatment failure and miconazole therapy can be considered as the best therapeutic choice in the management of vulvovaginitis.

A checklist of the species of Anastrepha with the families of their host plants and hymenopteran parasitoids in Brazil

International Nuclear Information System (INIS)

Zucchi, Roberto Antonio

2000-01-01

Many surveys on fruit flies have already been carried out by several researchers in Brazil while others are still going on. Most of these surveys were conducted in areas where no studies had been previously done. With these surveys, new species and new records of species were found in Brazil. Also, in this decade, several surveys on fruit fly braconid parasitoids were conducted. These data have been summarised recently, because of the great interest in the biological control of fruit flies in Brazil. Research on eucoilid fruit fly parasitoids have been largely neglected. However, taxonomic studies are being conducted on eucoilids associated with frugivorous flies (Tephritidae and Lonchaeidae) in Brazil. All the data on fruit flies, host plants and hymenopteran parasitoids are unfortunately scattered in the literature and frequently are only published as dissertations or congress abstracts which are not widely available. Even when submitted for publication, papers take a long time to come out in Brazil. Consequently, it is very difficult to get a list of the Anastrepha species in Brazil, or to determine which host plant species are associated with them. These data are of particular interest in the case of economically important species, especially those considered as quarantine pests. Therefore, such a list is very useful for regulatory entomologists and pest management programmes by listing the Anastrepha species in Brazil and their associated host plants and hymenopteran parasitoids. The objective of this paper is to gather some available records of the Anastrepha species, their host plants and hymenopteran parasitoids (Braconidae and Eucoilidae) published in Brazil. Due to the space limitation of this paper, only families of the host plants of the Anastrepha species are presented. In fact, this work is part of a research which deals with the preparation of a database for the Anastrepha species in Brazil

Interaction of bovine peripheral blood polymorphonuclear cells and Leptospira species; innate responses in the natural bovine reservoir host.

Science.gov (United States)

Cattle are the reservoir hosts of Leptospira borgpetersenii serovar Hardjo, and also be reservoir hosts of other Leptospira species such as L. kirschneri, and L. interrogans. As a reservoir host, cattle shed Leptospira, infecting other animals, including humans. Previous studies with human and murin...

The phylogeny and life cycle of two species of Profilicollis (Acanthocephala: Polymorphidae) in marine hosts off the Pacific coast of Chile.

Science.gov (United States)

Rodríguez, S M; D'Elía, G; Valdivia, N

2017-09-01

Resolving complex life cycles of parasites is a major goal of parasitological research. The aim of this study was to analyse the life cycle of two species of the genus Profilicollis, the taxonomy of which is still unstable and life cycles unclear. We extracted individuals of Profilicollis from two species of crustaceans (intermediate hosts) and four species of seagulls (definitive hosts) from sandy-shore and estuarine habitats along the south-east Pacific coast of Chile. Mitochondrial DNA analyses showed that two species of Profilicollis infected intermediate hosts from segregated habitats: while P. altmani larvae infected exclusively molecrabs of the genus Emerita from fully marine habitats, P. antarcticus larvae infected the crab Hemigrapsus crenulatus from estuarine habitats. Moreover, P. altmani completed its life cycle in four seagulls, Chroicocephalus maculipennis, Leucopheus pipixcan, Larus modestus and L. dominicanus, while P. antarcticus, on the other hand, completed its life cycle in the kelp gull L. dominicanus. Accordingly, our results show that two congeneric parasites use different and spatially segregated species as intermediate hosts, and both are capable of infecting one species of definitive hosts. As such, our analyses allow us to shed light on a complex interaction network.

Antimicrobial susceptibility pattern of acinetobacter species-one year experience in a tertiary care setting

International Nuclear Information System (INIS)

Qureshi, Z.A.; Abbasi, S.A.; Mirza, I.A.; Malik, N.; Sattar, A.

2012-01-01

Objective: To find out antimicrobial susceptibility pattern of Acinetobacter species isolated from 1 January 2009 through 31 December 2009 at Department of Microbiology, Armed Forces Institute of Pathology Rawalpindi. Materials and Methods: A total of 276 isolates of Acinetobacter spp yielded from various clinical specimens during the study period were included Routine conventional methods were used to identify various species of Acinetobacter and modified Kirby-Bauer disk diffusion method was used for susceptibility testing. Out of total 276 isolates, 176 (63.8%) turned out to be Acinetobacter baumannii and 100 (36.2%) were Acinetobacter johnsonii. Overall sensitivity of Acinetobacter spp against piperacillin/sulbactam, tigecycline, sulbactam/cefoperazone, piperacillin/tazobactam, imipenem, doxycycline, ceftazidime, ciprofloxacin, chloramphenicol, trimethoprim /sulfamethoxazole, ampicillin, gentamycin, ceftriaxone, amoxicillin/clavulanic acid and ampicillin were 64%,63%, 48%, 47%, 41%,39%,35%, 34%, 32%, 31 %, 29%, 19%, 18% and 5% respectively. Out of 276 isolates, 181 (66 %) were multidrug resistant while 33 (18 %) isolates were pan-drug resistant. (author)

Susceptibility of different bacterial species isolated from food animals to copper sulphate, zinc chloride and antimicrobial substances used for disinfection

DEFF Research Database (Denmark)

Aarestrup, Frank Møller; Hasman, Henrik

2004-01-01

that Danish bacterial isolates from livestock so far have not or have only to a limited degree developed resistance to antimicrobial compounds commonly used for disinfection. Acquired copper resistance was only found in enterococci. There were large differences in the intrinsic susceptibility of the different...... of susceptibilities to the different antimicrobial agents. Large variations were observed in the susceptibility of the different bacterial species to the different compounds. Staphylococci were in general very susceptible to all antimicrobial compounds tested. The Salmonella isolates were in general less susceptible...

Novel disease susceptibility factors for fungal necrotrophic pathogens in Arabidopsis.

Science.gov (United States)

Dobón, Albor; Canet, Juan Vicente; García-Andrade, Javier; Angulo, Carlos; Neumetzler, Lutz; Persson, Staffan; Vera, Pablo

2015-04-01

Host cells use an intricate signaling system to respond to invasions by pathogenic microorganisms. Although several signaling components of disease resistance against necrotrophic fungal pathogens have been identified, our understanding for how molecular components and host processes contribute to plant disease susceptibility is rather sparse. Here, we identified four transcription factors (TFs) from Arabidopsis that limit pathogen spread. Arabidopsis mutants defective in any of these TFs displayed increased disease susceptibility to Botrytis cinerea and Plectosphaerella cucumerina, and a general activation of non-immune host processes that contribute to plant disease susceptibility. Transcriptome analyses revealed that the mutants share a common transcriptional signature of 77 up-regulated genes. We characterized several of the up-regulated genes that encode peptides with a secretion signal, which we named PROVIR (for provirulence) factors. Forward and reverse genetic analyses revealed that many of the PROVIRs are important for disease susceptibility of the host to fungal necrotrophs. The TFs and PROVIRs identified in our work thus represent novel genetic determinants for plant disease susceptibility to necrotrophic fungal pathogens.

Novel disease susceptibility factors for fungal necrotrophic pathogens in Arabidopsis.

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Albor Dobón

2015-04-01

Full Text Available Host cells use an intricate signaling system to respond to invasions by pathogenic microorganisms. Although several signaling components of disease resistance against necrotrophic fungal pathogens have been identified, our understanding for how molecular components and host processes contribute to plant disease susceptibility is rather sparse. Here, we identified four transcription factors (TFs from Arabidopsis that limit pathogen spread. Arabidopsis mutants defective in any of these TFs displayed increased disease susceptibility to Botrytis cinerea and Plectosphaerella cucumerina, and a general activation of non-immune host processes that contribute to plant disease susceptibility. Transcriptome analyses revealed that the mutants share a common transcriptional signature of 77 up-regulated genes. We characterized several of the up-regulated genes that encode peptides with a secretion signal, which we named PROVIR (for provirulence factors. Forward and reverse genetic analyses revealed that many of the PROVIRs are important for disease susceptibility of the host to fungal necrotrophs. The TFs and PROVIRs identified in our work thus represent novel genetic determinants for plant disease susceptibility to necrotrophic fungal pathogens.

Differential tolerances to ocean acidification by parasites that share the same host.

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MacLeod, C D; Poulin, R

2015-06-01

Ocean acidification is predicted to cause major changes in marine ecosystem structure and function over the next century, as species-specific tolerances to acidified seawater may alter previously stable relationships between coexisting organisms. Such differential tolerances could affect marine host-parasite associations, as either host or parasite may prove more susceptible to the stressors associated with ocean acidification. Despite their important role in many ecological processes, parasites have not been studied in the context of ocean acidification. We tested the effects of low pH seawater on the cercariae and, where possible, the metacercariae of four species of marine trematode parasite. Acidified seawater (pH 7.6 and 7.4, 12.5 °C) caused a 40-60% reduction in cercarial longevity and a 0-78% reduction in metacercarial survival. However, the reduction in longevity and survival varied distinctly between parasite taxa, indicating that the effects of reduced pH may be species-specific. These results suggest that ocean acidification has the potential to reduce the transmission success of many trematode species, decrease parasite abundance and alter the fundamental regulatory role of multi-host parasites in marine ecosystems. Copyright © 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Dual RNA-sequencing of Eucalyptus nitens during Phytophthora cinnamomi challenge reveals pathogen and host factors influencing compatibility

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Febe Elizabeth Meyer

2016-03-01

Full Text Available Damage caused by Phytophthora cinnamomi Rands remains an important concern on forest tree species. The pathogen causes root and collar rot, stem cankers and dieback of various economically important Eucalyptus spp. In South Africa, susceptible cold tolerant Eucalyptus plantations have been affected by various Phytophthora spp. with P. cinnamomi considered one of the most virulent. The molecular basis of this compatible interaction is poorly understood. In this study, susceptible Eucalyptus nitens plants were stem inoculated with P. cinnamomi and tissue was harvested five days post inoculation. Dual RNA-sequencing, a technique which allows the concurrent detection of both pathogen and host transcripts during infection, was performed. Approximately 1% of the reads mapped to the draft genome of P. cinnamomi while 78% of the reads mapped to the Eucalyptus grandis genome. The highest expressed P. cinnamomi gene in planta was a putative crinkler effector (CRN1. Phylogenetic analysis indicated the high similarity of this P. cinnamomi CRN1 to that of Phytophthora infestans. Some CRN effectors are known to target host nuclei to suppress defense. In the host, over 1400 genes were significantly differentially expressed in comparison to mock inoculated trees, including suites of pathogenesis related (PR genes. In particular, a PR-9 peroxidase gene with a high similarity to a Carica papaya PR-9 ortholog previously shown to be suppressed upon infection by Phytophthora palmivora was down-regulated two-fold. This PR-9 gene may represent a cross-species effector target during P. cinnamomi infection. This study identified pathogenicity factors, potential manipulation targets and attempted host defense mechanisms activated by E. nitens that contributed to the susceptible outcome of the interaction.

Low susceptibility of invasive red lionfish (Pterois volitans to a generalist ectoparasite in both its introduced and native ranges.

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Paul C Sikkel

Full Text Available Escape from parasites in their native range is one of many mechanisms that can contribute to the success of an invasive species. Gnathiid isopods are blood-feeding ectoparasites that infest a wide range of fish hosts, mostly in coral reef habitats. They are ecologically similar to terrestrial ticks, with the ability to transmit blood-borne parasites and cause damage or even death to heavily infected hosts. Therefore, being highly resistant or highly susceptible to gnathiids can have significant fitness consequences for reef-associated fishes. Indo-Pacific red lionfish (Pterois volitans have invaded coastal habitats of the western tropical and subtropical Atlantic and Caribbean regions. We assessed the susceptibility of red lionfish to parasitic gnathiid isopods in both their native Pacific and introduced Atlantic ranges via experimental field studies during which lionfish and other, ecologically-similar reef fishes were caged and exposed to gnathiid infestation on shallow coral reefs. Lionfish in both ranges had very few gnathiids when compared with other species, suggesting that lionfish are not highly susceptible to infestation by generalist ectoparasitic gnathiids. While this pattern implies that release from gnathiid infestation is unlikely to contribute to the success of lionfish as invaders, it does suggest that in environments with high gnathiid densities, lionfish may have an advantage over species that are more susceptible to gnathiids. Also, because lionfish are not completely resistant to gnathiids, our results suggest that lionfish could possibly have transported blood parasites between their native Pacific and invaded Atlantic ranges.

Antimicrobial susceptibility of coagulase-negative Staphylococcus species isolated from bovine milk.

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Sawant, A A; Gillespie, B E; Oliver, S P

2009-02-16

Coagulase-negative Staphylococcus (CNS) isolates (n=168) obtained from milk from heifers and dairy cows were screened for minimum inhibitory concentration (MIC) to antimicrobials used commonly for mastitis therapy. Of the 10 CNS species included in the study, the predominant species were Staphylococcus chromogenes (n=61), Staphylococcus epidermidis (n=37), Staphylococcus hyicus (n=37), and Staphylococcus simulans (n=16). The majority of CNS was susceptible to ampicillin, oxacillin, cephalothin, and ceftiofur. Erythromycin and pirlimycin were also very effective in vitro inhibitors of CNS. The only exception was observed with S. epidermidis. Of 37 S. epidermidis evaluated, 13 (35%) exhibited efflux-based resistance to erythromycin (> or =16 microg/ml) encoded by msrA and one isolate carried ermC encoding ribosomal methylase-based resistance to both erythromycin (> or =64 microg/ml) and pirlimycin (> or =64 microg/ml). A total of 17 S. epidermidis, 11 S. chromogenes, and one S. hyicus exhibited phenotypic resistance to ampicillin (> or =0.5 microg/ml). Constitutive beta-lactamase production was observed in all ampicillin resistant isolates except 4 S. epidermidis that exhibited inducible beta-lactamase production. Induced beta-lactamase production was also observed in 13 S. epidermidis that were phenotypically susceptible to the entire MIC panel. All isolates that produced beta-lactamase either constitutively or by induction carried blaZ. S. epidermidis (n=12, 32%) that were resistant to methicillin (oxacillin > or =0.5 microg/ml) carried low affinity penicillin-binding protein encoded by mecA. Most multi-drug resistant (MDR) S. epidermidis (> or =2 resistance genes) were resistant to ampicillin, erythromycin and methicillin. All except one MDR S. epidermidis had icaAB, which encodes for polysaccharide intercellular adhesion. Based on pulsed field gel electrophoresis, MDR S. epidermidis were closely related genotypically, and were isolated from different cows on the

Species distribution and antifungal susceptibility patterns of Candida isolates from a public tertiary teaching hospital in the Eastern Cape Province, South Africa.

Science.gov (United States)

Mnge, P; Okeleye, B I; Vasaikar, S D; Apalata, T

2017-05-15

Candida species are the leading cause of invasive fungal infections, and over the past decade there has been an increased isolation of drug resistant Candida species. This study aimed to identify the species distribution of Candida isolates and to determine their unique antifungal susceptibility and resistance patterns. During a cross-sectional study, 209 Candida isolates (recovered from 206 clinical samples) were collected and their species distribution was determined using ChromAgar Candida. The Vitek-2 system (Biomerieux, South Africa) was used to determine minimum inhibitory concentrations (MICs) to azoles (fluconazole, voriconazole), echinocandins (caspofungin, micafungin), polyenes (amphotericin B) and flucytosine. Four species of Candida were isolated, of which C. albicans was the most frequent, isolated in 45.4% (95/209) of the isolates, followed by C. glabrata: 31.1% (65/209). The MICs of the different antifungal drugs varied amongst the species of Candida. From the 130 isolates tested for MICs, 90.77% (112/130) were susceptible to all antifungal drugs and 6.9% (9/130) of the isolates were multi-drug resistant. C. dubliniensis (n=2) isolates were susceptible to all the above mentioned antifungal drugs. There was no significant difference in species distribution amongst clinical specimens and between patients' genders (P>0.05). An increase in MIC values for fluconazole and flucytosine towards the resistance range was observed. To our knowledge, this is the first report on surveillance of Candida species distribution and antifungal susceptibility at a public tertiary teaching hospital in Eastern Cape, South Africa.

Genetic variation between susceptible and non-susceptible snails to Schistosoma infection using random amplified polymorphic DNA analysis (RAPDs Variação genética entre moluscos susceptíveis e não susceptíveis à infecção pelo Schistosoma através da análise do DNA polimórfico amplificado aleatóriamente (RAPDs

Directory of Open Access Journals (Sweden)

Abdel-Hamid Zaki ABDEL-HAMID

1999-09-01

Full Text Available Susceptibility of snails to infection by certain trematodes and their suitability as hosts for continued development has been a bewildering problem in host-parasite relationships. The present work emphasizes our interest in snail genetics to determine what genes or gene products are specifically responsible for susceptibility of snails to infection. High molecular weight DNA was extracted from both susceptible and non-susceptible snails within the same species Biomphalaria tenagophila. RAPD was undertaken to distinguish between the two types of snails. Random primers (10 mers were used to amplify the extracted DNA by the polymerase chain reaction (PCR followed by polyacrylamide gel electrophoresis (PAGE and silver staining. The results suggest that RAPD represents an efficient means of genome comparison, since many molecular markers were detected as genetic variations between susceptible and non-susceptible snails.A susceptibilidade de moluscos à infecção por certos trematódeos e a sua capacidade como hospedeiro para o contínuo desenvolvimento é o problema mais deslumbrante nas relações parasita hospedeiro. O presente trabalho, focaliza nosso interesse na genética dos moluscos para determinar quais genes ou produtos gênicos são especificamente responsáveis pela susceptibilidade do molusco à infecção. DNA de alto peso molecular, foi extraído de ambos moluscos susceptíveis e não susceptíveis da espécie Biomphalaria tenagophila. Iniciadores aleatórios com 10 pares de bases foram usados na amplificação aleatória (RAPD de ambos os DNAs e análise por eletroforese em gel de poliacrilamida e coloração com prata. Os resultados mostram que a amplificação aleatória do DNA representa um eficiente caminho para a comparação dos genomas desde que marcadores moleculares foram detectados como variantes genéticos entre os moluscos susceptíveis e não susceptíveis.

Dispersal limitation of Tillandsia species correlates with rain and host structure in a central Mexican tropical dry forest.

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Elizabeth Victoriano-Romero

Full Text Available Seed dispersal permits the colonization of favorable habitats and generation of new populations, facilitating escape from habitats that are in decline. There is little experimental evidence of the factors that limit epiphyte dispersion towards their hosts. In a tropical dry forest in central Mexico, we monitored the phenology of dispersion of epiphyte species of the genus Tillandsia; we tested experimentally whether precipitation could cause failures in seed dispersal and whether seed capture differs among vertical strata and between host species with high (Bursera copallifera and low (Conzattia multiflora epiphyte loads. With the exception of one species that presents late dispersion and low abundance, all of the species disperse prior to the onset of the rainy season. However, early rains immobilize the seeds, affecting up to 24% of the fruits in species with late dispersion. We observed that Tillandsia seeds reach both Bursera and Conzattia hosts, but found that adherence to the host is 4-5 times higher in Bursera. Furthermore, seeds liberated from Bursera travel shorter distances and up to half may remain within the same crown, while the highest seed capture takes place in the upper strata of the trees. We conclude that dispersion of Tillandsia seeds is limited by early rains and by the capture of seeds within the trees where populations concentrate. This pattern of capture also helps to explain the high concentrations of epiphytes in certain hosts, while trees with few epiphytes can be simultaneously considered deficient receivers and efficient exporters of seeds.

Comparative Susceptibility of Plants Native to the Appalachian Range of the United States to Inoculation With Phytophthora ramorum

Science.gov (United States)

R.G. Linderman; Patricia B. de Sá; E.A. Davis

2008-01-01

Phytophthora ramorum, cause of sudden oak death of trees or ramorum blight of other plant species, has many hosts. Some geographic regions, such as the Appalachian range of the eastern United States, are considered high risk of becoming infested with the pathogen because known susceptible plants occur there and climatic characteristics appear...

Importance of host feeding for parasitoids that attack honeydew-producing hosts

NARCIS (Netherlands)

Burger, J.M.S.; Komany, A.; Lenteren, van J.C.; Vet, L.E.M.

2005-01-01

Insect parasitoids lay their eggs in arthropods. Some parasitoid species not only use their arthropod host for oviposition but also for feeding. Host feeding provides nutrients to the adult female parasitoid. However, in many species, host feeding destroys an opportunity to oviposit. For parasitoids

Host-Specific Parvovirus Evolution in Nature Is Recapitulated by In Vitro Adaptation to Different Carnivore Species

Science.gov (United States)

Allison, Andrew B.; Kohler, Dennis J.; Ortega, Alicia; Hoover, Elizabeth A.; Grove, Daniel M.; Holmes, Edward C.; Parrish, Colin R.

2014-01-01

Canine parvovirus (CPV) emerged as a new pandemic pathogen of dogs in the 1970s and is closely related to feline panleukopenia virus (FPV), a parvovirus of cats and related carnivores. Although both viruses have wide host ranges, analysis of viral sequences recovered from different wild carnivore species, as shown here, demonstrated that >95% were derived from CPV-like viruses, suggesting that CPV is dominant in sylvatic cycles. Many viral sequences showed host-specific mutations in their capsid proteins, which were often close to sites known to control binding to the transferrin receptor (TfR), the host receptor for these carnivore parvoviruses, and which exhibited frequent parallel evolution. To further examine the process of host adaptation, we passaged parvoviruses with alternative backgrounds in cells from different carnivore hosts. Specific mutations were selected in several viruses and these differed depending on both the background of the virus and the host cells in which they were passaged. Strikingly, these in vitro mutations recapitulated many specific changes seen in viruses from natural populations, strongly suggesting they are host adaptive, and which were shown to result in fitness advantages over their parental virus. Comparison of the sequences of the transferrin receptors of the different carnivore species demonstrated that many mutations occurred in and around the apical domain where the virus binds, indicating that viral variants were likely selected through their fit to receptor structures. Some of the viruses accumulated high levels of variation upon passage in alternative hosts, while others could infect multiple different hosts with no or only a few additional mutations. Overall, these studies demonstrate that the evolutionary history of a virus, including how long it has been circulating and in which hosts, as well as its phylogenetic background, has a profound effect on determining viral host range. PMID:25375184

Host-specific parvovirus evolution in nature is recapitulated by in vitro adaptation to different carnivore species.

Directory of Open Access Journals (Sweden)

Andrew B Allison

2014-11-01

Full Text Available Canine parvovirus (CPV emerged as a new pandemic pathogen of dogs in the 1970s and is closely related to feline panleukopenia virus (FPV, a parvovirus of cats and related carnivores. Although both viruses have wide host ranges, analysis of viral sequences recovered from different wild carnivore species, as shown here, demonstrated that>95% were derived from CPV-like viruses, suggesting that CPV is dominant in sylvatic cycles. Many viral sequences showed host-specific mutations in their capsid proteins, which were often close to sites known to control binding to the transferrin receptor (TfR, the host receptor for these carnivore parvoviruses, and which exhibited frequent parallel evolution. To further examine the process of host adaptation, we passaged parvoviruses with alternative backgrounds in cells from different carnivore hosts. Specific mutations were selected in several viruses and these differed depending on both the background of the virus and the host cells in which they were passaged. Strikingly, these in vitro mutations recapitulated many specific changes seen in viruses from natural populations, strongly suggesting they are host adaptive, and which were shown to result in fitness advantages over their parental virus. Comparison of the sequences of the transferrin receptors of the different carnivore species demonstrated that many mutations occurred in and around the apical domain where the virus binds, indicating that viral variants were likely selected through their fit to receptor structures. Some of the viruses accumulated high levels of variation upon passage in alternative hosts, while others could infect multiple different hosts with no or only a few additional mutations. Overall, these studies demonstrate that the evolutionary history of a virus, including how long it has been circulating and in which hosts, as well as its phylogenetic background, has a profound effect on determining viral host range.

Ultrastructural characteristics of nurse cell-larva complex of four species of Trichinella in several hosts

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Sacchi L.

2001-06-01

Full Text Available The nurse cell-larva complex of nematodes of the genus Trichinella plays an Important role in the survival of the larva in decaying muscles, frequently favouring the transmission of the parasite in extreme environmental conditions. The ultrastructure of the nurse cell-larva complex in muscles from different hosts infected with T. nativa (a walrus and a polar bear, T. spiralis (horses and humans, T. pseudospiralis (a laboratory mouse and T. papuae (a laboratory mouse were examined. Analysis with transmission electron microscope showed that the typical nurse cell structure was present in all examined samples, irrespective of the species of larva, of the presence of a collagen capsule, of the age of infection and of the host species, suggesting that there exists a molecular mechanism that in the first stage of larva invasion is similar for encapsulated and non-encapsulated species.

How do PrPSc Prions Spread between Host Species, and within Hosts?

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Neil A. Mabbott

2017-11-01

Full Text Available Prion diseases are sub-acute neurodegenerative diseases that affect humans and some domestic and free-ranging animals. Infectious prion agents are considered to comprise solely of abnormally folded isoforms of the cellular prion protein known as PrPSc. Pathology during prion disease is restricted to the central nervous system where it causes extensive neurodegeneration and ultimately leads to the death of the host. The first half of this review provides a thorough account of our understanding of the various ways in which PrPSc prions may spread between individuals within a population, both horizontally and vertically. Many natural prion diseases are acquired peripherally, such as by oral exposure, lesions to skin or mucous membranes, and possibly also via the nasal cavity. Following peripheral exposure, some prions accumulate to high levels within the secondary lymphoid organs as they make their journey from the site of infection to the brain, a process termed neuroinvasion. The replication of PrPSc prions within secondary lymphoid organs is important for their efficient spread to the brain. The second half of this review describes the key tissues, cells and molecules which are involved in the propagation of PrPSc prions from peripheral sites of exposure (such as the lumen of the intestine to the brain. This section also considers how additional factors such as inflammation and aging might influence prion disease susceptibility.

Host-Plant Specialization Mediates the Influence of Plant Abundance on Host Use by Flower Head-Feeding Insects.

Science.gov (United States)

Nobre, Paola A F; Bergamini, Leonardo L; Lewinsohn, Thomas M; Jorge, Leonardo R; Almeida-Neto, Mário

2016-02-01

Among-population variation in host use is a common phenomenon in herbivorous insects. The simplest and most trivial explanation for such variation in host use is the among-site variation in plant species composition. Another aspect that can influence spatial variation in host use is the relative abundance of each host-plant species compared to all available hosts. Here, we used endophagous insects that develop in flower heads of Asteraceae species as a study system to investigate how plant abundance influences the pattern of host-plant use by herbivorous insects with distinct levels of host-range specialization. Only herbivores recorded on three or more host species were included in this study. In particular, we tested two related hypotheses: 1) plant abundance has a positive effect on the host-plant preference of herbivorous insects, and 2) the relative importance of plant abundance to host-plant preference is greater for herbivorous species that use a wider range of host-plant species. We analyzed 11 herbivore species in 20 remnants of Cerrado in Southeastern Brazil. For 8 out of 11 herbivore species, plant abundance had a positive influence on host use. In contrast to our expectation, both the most specialized and the most generalist herbivores showed a stronger positive effect of plant species abundance in host use. Thus, we found evidence that although the abundance of plant species is a major factor determining the preferential use of host plants, its relative importance is mediated by the host-range specialization of herbivores.

From the Atlantic Forest to the borders of Amazonia: species richness, distribution, and host association of ectoparasitic flies (Diptera: Nycteribiidae and Streblidae) in northeastern Brazil.

Science.gov (United States)

Barbier, Eder; Bernard, Enrico

2017-11-01

Better knowledge of the geographical distribution of parasites and their hosts can contribute to clarifying aspects of host specificity, as well as on the interactions among hosts, parasites, and the environment in which both exist. Ectoparasitic flies of the Nycteribiidae and Streblidae families are highly specialized hematophagous parasites of bats, whose distributional patterns, species richness, and associations with hosts remain underexplored and poorly known in Brazil. Here, we used information available in the literature and unpublished data to verify if the occurrence of bat hosts in a given environment influences the occurrence and distribution of nycteribiid and streblid flies in different ecoregions in the northeastern Brazil. We evaluate species richness and similarity between ecoregions and tested correlations between species richness and the number of studies in each ecoregion and federative unit. We recorded 50 species and 15 genera of bat ectoparasitic flies on 36 species and 27 genera of bat hosts. The Atlantic Forest had the highest fly species richness (n = 31; 62%), followed by Caatinga (n = 27; 54%). We detected the formation of distinct groups, with low species overlap between ecoregions for both flies and bats. Fly species richness was correlated with host species richness and with the number of studies in each federative unit, but not with the number of studies by ecoregion. Due to the formation of distinct groups with low species overlap for both groups, host availability is likely to be one of the factors that most influence the occurrence of highly specific flies. We also discuss host specificity for some species, produced an updated list of species and distribution for both nycteribiid and streblid flies with information on interaction networks, and conclude by presenting recommendations for more effective inventories of bat ectoparasites in the future.

The relationship between host lifespan and pathogen reservoir potential: an analysis in the system Arabidopsis thaliana--cucumber mosaic virus.

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Jean Michel Hily

2014-11-01

Full Text Available Identification of the determinants of pathogen reservoir potential is central to understand disease emergence. It has been proposed that host lifespan is one such determinant: short-lived hosts will invest less in costly defenses against pathogens, so that they will be more susceptible to infection, more competent as sources of infection and/or will sustain larger vector populations, thus being effective reservoirs for the infection of long-lived hosts. This hypothesis is sustained by analyses of different hosts of multihost pathogens, but not of different genotypes of the same host species. Here we examined this hypothesis by comparing two genotypes of the plant Arabidopsis thaliana that differ largely both in life-span and in tolerance to its natural pathogen Cucumber mosaic virus (CMV. Experiments with the aphid vector Myzus persicae showed that both genotypes were similarly competent as sources for virus transmission, but the short-lived genotype was more susceptible to infection and was able to sustain larger vector populations. To explore how differences in defense against CMV and its vector relate to reservoir potential, we developed a model that was run for a set of experimentally-determined parameters, and for a realistic range of host plant and vector population densities. Model simulations showed that the less efficient defenses of the short-lived genotype resulted in higher reservoir potential, which in heterogeneous host populations may be balanced by the longer infectious period of the long-lived genotype. This balance was modulated by the demography of both host and vector populations, and by the genetic composition of the host population. Thus, within-species genetic diversity for lifespan and defenses against pathogens will result in polymorphisms for pathogen reservoir potential, which will condition within-population infection dynamics. These results are relevant for a better understanding of host-pathogen co-evolution, and of

HostPhinder: A Phage Host Prediction Tool

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Julia Villarroel

2016-05-01

Full Text Available The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2].

Selective logging in tropical forests decreases the robustness of liana-tree interaction networks to the loss of host tree species.

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Magrach, Ainhoa; Senior, Rebecca A; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F; Santamaria, Luis; Edwards, David P

2016-03-16

Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the 'health' and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana-tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of 'extinction debt'. © 2016 The Author(s).

Selective logging in tropical forests decreases the robustness of liana–tree interaction networks to the loss of host tree species

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Magrach, Ainhoa; Senior, Rebecca A.; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F.; Santamaria, Luis; Edwards, David P.

2016-01-01

Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the ‘health’ and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana–tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of ‘extinction debt’. PMID:26936241

Susceptibility to antibiotics of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host Aglaophenia octodonta (Cnidaria, Hydrozoa).

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Stabili, Loredana; Gravili, Cinzia; Boero, Ferdinando; Tredici, Salvatore M; Alifano, Pietro

2010-04-01

Vibrio harveyi is the major causal organism of vibriosis, causing potential devastation to diverse ranges of marine invertebrates over a wide geographical area. These microorganisms, however, are phenotypically diverse, and many of the isolates are also resistant to multiple antibiotics. In a previous study, we described a previously unknown association between Vibrio sp. AO1, a luminous bacterium related to the species V. harveyi, and the benthic hydrozoan Aglaophenia octodonta. In this study, we analyzed the susceptibility to antibiotics (ampicillin, streptomycin, tetracycline, or co-trimoxazole = mix of sulfamethoxazole and trimetoprim) of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host by using microcosm experiments. The results of minimum inhibitory concentration (MIC) experiments demonstrated that Vibrio sp. AO1 was highly resistant to ampicillin and streptomycin in pure culture. Nevertheless, these antibiotics, when used at sub-MIC values, significantly reduced the hydroid fluorescence. Co-trimoxazole showed the highest inhibitory effect on fluorescence of A. octodonta. However, in all treatments, the fluorescence was reduced after 48 h, but never disappeared completely around the folds along the hydrocaulus and at the base of the hydrothecae of A. octodonta when the antibiotic was used at concentration completely inhibiting growth in vitro. The apparent discrepancy between the MIC data and the fluorescence patterns may be due to either heterogeneity of the bacterial population in terms of antibiotic susceptibility or specific chemical-physical conditions of the hydroid microenvironment that may decrease the antibiotic susceptibility of the whole population. The latter hypothesis is supported by scanning electron microscope evidence for development of bacterial biofilm on the hydroid surface. On the basis of the results obtained, we infer that A. octodonta might behave as a reservoir of antibiotic multiresistant bacteria

Host and Potential Vector Susceptibility to an Emerging Orbivirus in the United States: Epizootic Hemorrhagic Disease Virus Serotype 6.

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Ruder, M G; Stallknecht, D E; Allison, A B; Mead, D G; Carter, D L; Howerth, E W

2016-05-01

Epizootic hemorrhagic disease viruses (EHDVs) are orbiviruses transmitted by Culicoides biting midges to domestic and wild ruminants. EHDV-1 and EHDV-2 are endemic in the United States, where epizootic hemorrhagic disease is the most significant viral disease of white-tailed deer (WTD;Odocoileus virginianus) and reports of epizootic hemorrhagic disease in cattle are increasing. In 2006, a reassortant EHDV-6 was isolated from dead WTD in Indiana and has been detected each subsequent year over a wide geographic region. Since EHDV-6 is not a historically endemic serotype in the United States, it is important to understand infection outcome in potential hosts. Specifically, we aimed to evaluate the pathogenicity of the virus in 2 primary US ruminant hosts (WTD and cattle) and the susceptibility of a confirmed US vector (Culicoides sonorensis). Five WTD and 4 cattle were inoculated with >10(6)TCID50EHDV-6 by intradermal and subcutaneous injection. All 5 WTD exhibited moderate to severe disease, and 3 died. Viremia was first detected 3 to 5 days postinfection (dpi) with surviving animals seroconverting by 10 dpi. Two of 4 inoculated cattle had detectable viremia, 5 to 10 dpi and 7 to 24 dpi, respectively. No clinical, hematologic, or pathologic abnormalities were observed. Antibodies were detected by 10 dpi in 3 of 4 cows.C. sonorensis were fed on WTD blood spiked with EHDV-6 and held for 4 to 14 days postfeeding at 25°C. From 4 to 14 days postfeeding, 19 of 171 midges were virus isolation positive and 6 of 171 had ≥10(2.7)TCID50EHDV-6. Although outcomes varied, these studies demonstrate the susceptibility of ruminant and vector hosts in the United States for this recently emerged EHDV serotype. © The Author(s) 2015.

Species distribution and in vitro antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis

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Rijs Antonius JMM

2008-08-01

Full Text Available Abstract Background In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis. Methods A total of 296 clinical oral yeasts were isolated from 292 HIV-infected patients with oropharyngeal candidiasis at the Muhimbili National Hospital, Dar es Salaam, Tanzania. Identification of the yeasts was performed using standard phenotypic methods. Antifungal susceptibility to fluconazole, itraconazole, miconazole, clotrimazole, amphotericin B and nystatin was assessed using a broth microdilution format according to the guidelines of the Clinical and Laboratory Standard Institute (CLSI; M27-A2. Results Candida albicans was the most frequently isolated species from 250 (84.5% patients followed by C. glabrata from 20 (6.8% patients, and C. krusei from 10 (3.4% patients. There was no observed significant difference in species distribution between patients with primary and recurrent oropharyngeal candidiasis, but isolates cultured from patients previously treated were significantly less susceptible to the azole compounds compared to those cultured from antifungal naïve patients. Conclusion C. albicans was the most frequently isolated species from patients with oropharyngeal candidiasis. Oral yeast isolates from Tanzania had high level susceptibility to the antifungal agents tested. Recurrent oropharyngeal candidiasis and previous antifungal therapy significantly correlated with reduced susceptibility to azoles antifungal agents.

Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut.

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De Waele, D; Jordaan, E M; Basson, S

1990-07-01

The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed species; population densities increased in peanut hulls and caused severe damage to seeds of peanut grown after weeds. Roots of purple nutsedge left in the soil suppressed populations of D. destructor and root and pod development in peanut grown after the weed. However, nematode populations in peanut hulls and seeds were not suppressed. Some weed species, especially purple nutsedge which is common in peanut fields, can be used to indicate the presence of D. destructor in the absence of peanut.

Defense response of susceptible and resistant Biomphalaria alexandrina snails against Schistosoma mansoni infection

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Iman F. Abou-El-Naga

2012-09-01

Full Text Available In Egypt, Biomphalaria alexandrina is the intermediate host for Schistosoma mansoni. The fates of Schistosoma miracidia in the snails varies between different species of Biomphalaria. The internal defense system is one of the factors that influence the susceptibility pattern of the snails. The interaction between Biomphalaria snails and S. mansoni needs to be identified for each species, and even between the members of the same species with different degrees of susceptibility. In the present study, the first generation of susceptible and resistant parents of B. alexandrina was examined histologically at the 30th day post exposure. The study includes the characterization of the immune response, as expressed by tissue reactions, of susceptible and resistant B. alexandrina snails against S. mansoni. It was also designed to determine the impact of the resistance increase in parent snails, on the mechanisms of interaction of their offspring against infection. The results showed that the infection rate of the offspring from the susceptible parents was 92%. No susceptible offspring was produced from the resistant parents. When the parents were of equal number of susceptible and resistant snails, they gave an offspring with an infection rate of 20%. Susceptible snails that had susceptible parents showed a higher degree of susceptibility than those that had both susceptible and resistant parents. A common feature of the resistant snails was the absence of any viable parasites. The tissue reactions of the resistant snails having only resistant parents occurred at the site of miracidial penetration. In resistant snails for which susceptible ones were included in their parents, the reactions occurred in the deep tissues. These results characterized the immune response of B. alexandrina snails against Schistosoma infection which was found to occur by two different mechanisms. One type of defense occurs in highly resistant snails, and employs direct

Comparison of agar dilution and antibiotic gradient strip test with broth microdilution for susceptibility testing of swine Brachyspira species.

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Mirajkar, Nandita S; Gebhart, Connie J

2016-03-01

Production-limiting diseases in swine caused by Brachyspira are characterized by mucohemorrhagic diarrhea (B. hyodysenteriae and "B. hampsonii") or mild colitis (B. pilosicoli), while B. murdochii is often isolated from healthy pigs. Emergence of novel pathogenic Brachyspira species and strains with reduced susceptibility to commonly used antimicrobials has reinforced the need for standardized susceptibility testing. Two methods are currently used for Brachyspira susceptibility testing: agar dilution (AD) and broth microdilution (BMD). However, these tests have primarily been used for B. hyodysenteriae and rarely for B. pilosicoli. Information on the use of commercial susceptibility testing products such as antibiotic gradient strips is lacking. Our main objective was to validate and compare the susceptibility results, measured as the minimum inhibitory concentration (MIC), of 6 antimicrobials for 4 Brachyspira species (B. hyodysenteriae, "B. hampsonii", B. pilosicoli, and B. murdochii) by BMD and AD (tiamulin, valnemulin, lincomycin, tylosin, and carbadox) or antibiotic gradient strip (doxycycline) methods. In general, the results of a high percentage of all 4 Brachyspira species differed by ±1 log2 dilution or less by BMD and AD for tiamulin, valnemulin, lincomycin, and tylosin, and by BMD and antibiotic gradient strip for doxycycline. The carbadox MICs obtained by BMD were 1-5 doubling dilutions different than those obtained by AD. BMD for Brachyspira was quicker to perform with less ambiguous interpretation of results when compared with AD and antibiotic gradient strip methods, and the results confirm the utility of BMD in routine diagnostics. © 2016 The Author(s).

Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut

OpenAIRE

De Waele, D.; Jordaan, Elizabeth M.; Basson, Selmaré

1990-01-01

The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed spec...

Recurrent evolution of host and vector association in bacteria of the Borrelia burgdorferi sensu lato species complex.

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Becker, Noémie S; Margos, Gabriele; Blum, Helmut; Krebs, Stefan; Graf, Alexander; Lane, Robert S; Castillo-Ramírez, Santiago; Sing, Andreas; Fingerle, Volker

2016-09-15

The Borrelia burgdorferi sensu lato (s.l.) species complex consists of tick-transmitted bacteria and currently comprises approximately 20 named and proposed genospecies some of which are known to cause Lyme Borreliosis. Species have been defined via genetic distances and ecological niches they occupy. Understanding the evolutionary relationship of species of the complex is fundamental to explaining patterns of speciation. This in turn forms a crucial basis to frame testable hypotheses concerning the underlying processes including host and vector adaptations. Illumina Technology was used to obtain genome-wide sequence data for 93 strains of 14 named genospecies of the B. burgdorferi species complex and genomic data already published for 18 additional strain (including one new species) was added. Phylogenetic reconstruction based on 114 orthologous single copy genes shows that the genospecies represent clearly distinguishable taxa with recent and still ongoing speciation events apparent in Europe and Asia. The position of Borrelia species in the phylogeny is consistent with host associations constituting a major driver for speciation. Interestingly, the data also demonstrate that vector associations are an additional driver for diversification in this tick-borne species complex. This is particularly obvious in B. bavariensis, a rodent adapted species that has diverged from the bird-associated B. garinii most likely in Asia. It now consists of two populations one of which most probably invaded Europe following adaptation to a new vector (Ixodes ricinus) and currently expands its distribution range. The results imply that genotypes/species with novel properties regarding host or vector associations have evolved recurrently during the history of the species complex and may emerge at any time. We suggest that the finding of vector associations as a driver for diversification may be a general pattern for tick-borne pathogens. The core genome analysis presented here

Crown sheath rot of rice: host-range and varietal resistance to Gaeumannomyces graminis var. graminis

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Cecília do Nascimento Peixoto

2014-09-01

Full Text Available Several gramineous plants occurring in rice fields show symptoms of crown sheath rot of rice, caused by Gaeumannomyces graminis var. graminis (Ggg, under natural conditions of infection. The pathogenicity of the Ggg-a 01 isolate, collected from rice, was tested on seven grass species and eight cereals, under greenhouse conditions, in order to get information on host-range and resistance of rice genotypes to crown sheath rot. The inoculation tests showed that the rice isolate was pathogenic to weeds such as Echinochloa crusgalli, Pennisetum setosum, Brachiaria sp., Digitaria horizontalis, Brachiaria plantaginea, Eleusine indica and Cenchrus echinatus, and that these species are potential hosts to the pathogen. Winter cereals such as wheat, oat, rye, barley and triticale, as well as sorghum, maize and millet, presented different degrees of susceptibility to the Ggg-a isolate. Significant differences were observed in relation to lesion height and production of hyphopodia and perithecia on culms. Perithecia were not observed on millet, sorghum, southern sandbur and maize. The resistance of 58 upland rice genotypes was tested, and the SCIA16 and SCIA08 genotypes presented lesion height significantly smaller, being considered resistant, when compared to the highly susceptible CNAS10351 genotype.

Host Defense Mechanisms against Bark Beetle Attack Differ between Ponderosa and Lodgepole Pines

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Daniel R. West

2016-10-01

Full Text Available Conifer defenses against bark beetle attack include, but are not limited to, quantitative and qualitative defenses produced prior to attack. Our objective was to assess host defenses of lodgepole pine and ponderosa pine from ecotone stands. These stands provide a transition of host species for mountain pine beetle (Dendroctonus ponderosae; MPB. We asked two questions: (1 do the preformed quantitative host defenses (amount of resin and (2 the preformed qualitative host defenses (monoterpene constituents differ between lodgepole and ponderosa pines. We collected oleoresins at three locations in the Southern Rocky Mountains from 56 pairs of the pine species of similar size and growing conditions. The amount of preformed-ponderosa pine oleoresins exuded in 24 h (mg was almost four times that of lodgepole pine. Total qualitative preformed monoterpenes did not differ between the two hosts, though we found differences in all but three monoterpenes. No differences were detected in α-pinene, γ-terpinene, and bornyl acetate. We found greater concentrations of limonene, β-phellandrene, and cymene in lodgepole pines, whereas β-pinene, 3-carene, myrcene, and terpinolene were greater in ponderosa pine. Although we found differences both in quantitative and qualitative preformed oleoresin defenses, the ecological relevance of these differences to bark beetle susceptibility have not been fully tested.

Host age modulates parasite infectivity, virulence and reproduction.

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Izhar, Rony; Ben-Ami, Frida

2015-07-01

Host age is one of the most striking differences among hosts within most populations, but there is very little data on how age-dependent effects impact ecological and evolutionary dynamics of both the host and the parasite. Here, we examined the influence of host age (juveniles, young and old adults) at parasite exposure on host susceptibility, fecundity and survival as well as parasite transmission, using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa. Younger D. magna were more susceptible to infection than older ones, regardless of host or parasite clone. Also, younger-infected D. magna became castrated faster than older hosts, but host and parasite clone effects contributed to this trait as well. Furthermore, the early-infected D. magna produced considerably more parasite transmission stages than late-infected ones, while host age at exposure did not affect virulence as it is defined in models (host mortality). When virulence is defined more broadly as the negative effects of infection on host fitness, by integrating the parasitic effects on host fecundity and mortality, then host age at exposure seems to slide along a negative relationship between host and parasite fitness. Thus, the virulence-transmission trade-off differs strongly among age classes, which in turn affects predictions of optimal virulence. Age-dependent effects on host susceptibility, virulence and parasite transmission could pose an important challenge for experimental and theoretical studies of infectious disease dynamics and disease ecology. Our results present a call for a more explicit stage-structured theory for disease, which will incorporate age-dependent epidemiological parameters. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Endoparasite fauna of five Gadiformes fish species from the coast of Chile: host ecology versus phylogeny.

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Chávez, R A; González, M T; Oliva, M E; Valdivia, I M

2012-03-01

The aims of the present study were to compare, using multivariate analyses, the degree of similarity of the endoparasite fauna of five fish species belonging to the order Gadiformes: Merluccius gayi, Merluccius australis, Macruronus magellanicus (Gadoidei) and Micromesistius australis and Nezumia pulchella (Macrouroidei), from the southern and central Chilean coast, and to evaluate whether the composition of the endoparasite fauna was determined by phylogenetic or ecological relationships. We employed our database of Merluccius australis, M. magellanicus and Micromesistius australis, which was complemented with published information for M. magellanicus, Merluccius australis, Micromesistius australis, M. gayi and N. pulchella. A higher number of endoparasite species was recorded for Merluccius australis, Micromesistius australis and M. magellanicus, namely Anisakis sp. and Hepatoxylon trichiuri, which is the most prevalent parasite among these hosts. Aporocotyle wilhelmi and Hysterothylacium sp. were detected only in M. gayi, whereas Lepidapedon sp. was found exclusively in N. pulchella. These results suggest that fish ecology rather than host phylogeny was the most important factor for the determination of similarity in parasite composition. This result could be explained by the similar trophic patterns of hosts and by the predominance of generalist larval species among these fish parasite communities.

Candida species isolated from different body sites and their antifungal susceptibility pattern: Cross-analysis of Candida albicans and Candida glabrata biofilms.

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Cataldi, Valentina; Di Campli, Emanuela; Fazii, Paolo; Traini, Tonino; Cellini, Luigina; Di Giulio, Mara

2017-08-01

Candida species are regular commensal in humans, but-especially in immunocompromised patients-they represent opportunistic pathogens giving rise to systemic infection. The aim of the present work was to isolate and characterize for their antifungal profile Candida species from different body sites and to analyze the biofilms produced by C. albicans and C. glabrata isolates. Eighty-one strains of Candida species from 77 patients were identified. Epidemiological study showed that the most isolated species were C. albicans (44), C. glabrata (13) and C. parapsilosis (13) mainly from Hematology, Infectious Diseases, Medicine, Neonatology and Oncology Divisions, the majority of the biological samples were swabs (44) and blood cultures (16). The analysis of the biofilm formation was performed at 24 and 48-hours comparing resistant and susceptible strains of C. albicans to resistant and susceptible strains of C. glabrata. Candida albicans has a greater ability to form biofilm compared to C. glabrata, both in the susceptible and resistant strains reaching maturity after 24 hours with a complex structure composed of blastospores, pseudohyphae, and hyphae embedded in a matrix. On the contrary, C. glabrata biofilm was composed exclusively of blastospores that in the resistant strain, after 24 hours, were organized in a compact multilayer different to the discontinuous structure observed in the susceptible analyzed strains. In conclusion, the increasing of the incidence of Candida species infection together with their emerging drug resistance also related to the biofilm forming capability underline the need to monitor their distribution and susceptibility patterns for improving the surveillance and for a correct management of the infection. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparative evidence for a link between Peyer's patch development and susceptibility to transmissible spongiform encephalopathies

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Rhind Susan M

2006-01-01

Full Text Available Abstract Background Epidemiological analyses indicate that the age distribution of natural cases of transmissible spongiform encephalopathies (TSEs reflect age-related risk of infection, however, the underlying mechanisms remain poorly understood. Using a comparative approach, we tested the hypothesis that, there is a significant correlation between risk of infection for scrapie, bovine spongiform encephalopathy (BSE and variant CJD (vCJD, and the development of lymphoid tissue in the gut. Methods Using anatomical data and estimates of risk of infection in mathematical models (which included results from previously published studies for sheep, cattle and humans, we calculated the Spearman's rank correlation coefficient, rs, between available measures of Peyer's patch (PP development and the estimated risk of infection for an individual of the corresponding age. Results There was a significant correlation between the measures of PP development and the estimated risk of TSE infection; the two age-related distributions peaked in the same age groups. This result was obtained for each of the three host species: for sheep, surface area of ileal PP tissue vs risk of infection, rs = 0.913 (n = 19, P s = 0.933 (n = 19, P s = 0.693 (n = 94, P s = 0.384 (n = 46, P = 0.008. In addition, when changes in exposure associated with BSE-contaminated meat were accounted for, the two age-related patterns for humans remained concordant: rs = 0.360 (n = 46, P = 0.014. Conclusion Our findings suggest that, for sheep, cattle and humans alike there is an association between PP development (or a correlate of PP development and susceptibility to natural TSE infection. This association may explain changes in susceptibility with host age, and differences in the age-susceptibility relationship between host species.

Powdery mildew of Chrysanthemum × morifolium: phylogeny and taxonomy in the context of Golovinomyces species on Asteraceae hosts.

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Bradshaw, Michael; Braun, Uwe; Götz, Monika; Meeboon, Jamjan; Takamatsu, Susumu

2017-01-01

The taxonomic history of the common powdery mildew of Chrysanthemum × morifolium (chrysanthemum, florist's daisy), originally described in Germany as Oidium chrysanthemi, is discussed. The position of O. chrysanthemi was investigated on the basis of morphological traits and molecular phylogenetic analyses. Based on the results of this study, this species, which is closely related to Golovinomyces artemisae, was reassessed and reallocated to Golovinomyces. The phylogenetic analysis and taxonomic reassessment of the chrysanthemum powdery mildew is supplemented by a morphological description, a summary of its worldwide distribution data, and a brief discussion of the introduction of this fungus to North America. G. chrysanthemi differs from true G. artemisiae in that it has much longer conidiophores, is not constricted at the base, and has much larger and most importantly longer conidia. The close affinity of Golovinomyces to Artemisia and Chrysanthemum species signifies a coevolutionary event between the powdery mildews concerned and their host species in the subtribe Artemisiinae (Asteraceae tribe Anthemideae). This conclusion is fully supported by the current phylogeny and taxonomy of the host plant genera and the coevolution that occurred with the host and pathogen. The following powdery mildew species, which are associated with hosts belonging to the tribe Anthemideae of the Asteraceae, are epitypified: Alphitomorpha depressa β artemisiae (≡ Alphitomorpha artemisiae), Erysiphe artemisiae, and Oidium chrysanthemi. Erysiphe macrocarpa is neotypified. Their sequences were retrieved from the epitype collections and have been added to the phylogenetic tree. Golovinomyces orontii, an additional powdery mildew species on Chrysanthemum ×morifolium, is reported. This species is rarely found as a spontaneous infection and was obtained from inoculation experiments.

Virulence factors and antibiotic susceptibility pattern of Acinetobacter species in a tertiary care hospital in Bangladesh

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Azizun Nahar

2012-01-01

Full Text Available Acinetobacter species are aerobic Gram variable coccobacilli that are now emerging as an important nosocomial pathogen. Infections caused by them are difficult to control due to multidrug resistance. The purpose of this study was to detect virulence factors namely gelatinase production, biofilm formation and antibiotic susceptibility of Acinetobacter species. Two hundred fifty six clinical samples collected from Bangabandhu Sheikh Mujib medical University (BSMMU and from burn unit of Dhaka Medical College Hospital were included in the study. Gelatinase production was seen on Luria Bertani agar media containing gelatin (30 gm/l and biofilm formation was detected in microtiter plate assay. Out of 256 clinical samples, 52 (20.3% were Acinetobacter species. Out of 52 Acinetobacter isolates, none were gelatinase producer but 39 (75% were found biofilm producers. Acinetobacter isolates were 100% resistant to ceftazidime, cefotaxime cefuroxime and ceftriaxone. High level of resistance was also recorded for amoxicillin (98.1%, aztreonam (98.1%, gentamicin (90.4%, ciprofloxacin (73.1%, amikacin (57.6%, netilmicin (53.8% and imipenem (44.2%. Susceptibility to colistin was maximum (96.2%. The present study demonstrated a high propensity of biofilm formation by the clinical isolates of Acinetobacter species and most of the Acinetobacter were multidrug resistant. Ibrahim Med. Coll. J. 2012; 6(1: 27-30

Molecular identification, antifungal susceptibility profile, and biofilm formation of clinical and environmental Rhodotorula species isolates.

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Nunes, Jorge Meneses; Bizerra, Fernando César; Ferreira, Renata Carmona E; Colombo, Arnaldo Lopes

2013-01-01

Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC(50)/MIC(90), 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula

New African species of Echinobothrium (Cestoda: Diphyllidea) and implications for the identities of their skate hosts.

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Caira, J N; Rodriguez, N; Pickering, M

2013-10-01

Two new species of diphyllidean cestodes of the genus Echinobothrium, each hosted by a different skate species in the Raja miraletus complex, are described. Echinobothrium mercedesae n. sp. is described from R. cf. miraletus 2 off Senegal. Echinobothrium yiae n. sp. is described from R. cf. miraletus 1 off South Africa. Both species are small worms that differ from their 29 described congeners in the combination of number of cephalic peduncle spines per column, hook formula, number and arrangement of testes, and arrangement of vitelline follicles. They are easily distinguished from one another in that whereas the vitelline follicles of E. yiae n. sp. are circumcortical, they are lateral in E. mercedesae n. sp., and also in number of cephalic peduncle spines per column (14-17 vs. 10-12). Echinobothrium yiae n. sp. is also unusual in that the cephalic peduncle spines stop short of the anterior margin of the peduncle. In addition, although the paucity of available material precluded their formal description, evidence of 2 additional new species parasitizing R. miraletus also from Senegal is presented. In combination these worms provide support for the interpretation that what is currently recognized as Raja miraletus actually consists of a complex of geographically restricted species, rather than a polymorphic species of multiple parapatric or allopatrically distributed populations. This interpretation is not only supported by previously published molecular data, but also by newly collected morphological data involving differences in the color patterns of disc ocelli among host specimens of the 3 forms available as a result of digital efforts to ensure the accuracy of host identifications, which are also presented here.

Expression of human CD81 differently affects host cell susceptibility to malaria sporozoites depending on the Plasmodium species.

NARCIS (Netherlands)

Silvie, O.; Greco, C.; Franetich, J.F.; Dubart-Kupperschmitt, A.; Hannoun, L.; Gemert, G.J.A. van; Sauerwein, R.W.; Levy, S.; Boucheix, C.; Rubinstein, E.; Mazier, D.

2006-01-01

Plasmodium sporozoites can enter host cells by two distinct pathways, either through disruption of the plasma membrane followed by parasite transmigration through cells, or by formation of a parasitophorous vacuole (PV) where the parasite further differentiates into a replicative exo-erythrocytic

Co-extinction in a host-parasite network: identifying key hosts for network stability.

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Dallas, Tad; Cornelius, Emily

2015-08-17

Parasites comprise a substantial portion of total biodiversity. Ultimately, this means that host extinction could result in many secondary extinctions of obligate parasites and potentially alter host-parasite network structure. Here, we examined a highly resolved fish-parasite network to determine key hosts responsible for maintaining parasite diversity and network structure (quantified here as nestedness and modularity). We evaluated four possible host extinction orders and compared the resulting co-extinction dynamics to random extinction simulations; including host removal based on estimated extinction risk, parasite species richness and host level contributions to nestedness and modularity. We found that all extinction orders, except the one based on realistic extinction risk, resulted in faster declines in parasite diversity and network structure relative to random biodiversity loss. Further, we determined species-level contributions to network structure were best predicted by parasite species richness and host family. Taken together, we demonstrate that a small proportion of hosts contribute substantially to network structure and that removal of these hosts results in rapid declines in parasite diversity and network structure. As network stability can potentially be inferred through measures of network structure, our findings may provide insight into species traits that confer stability.

The New World Gibbobruchus Pic (Coleoptera, Chrysomelidae, Bruchinae): description of a new species and phylogenetic insights into the evolution of host associations and biogeography.

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Manfio, Daiara; Jorge, Isaac R; Morse, Geoffrey E; Ribeiro-Costa, Cibele S

2016-04-18

The seed beetle Gibbobruchus tridentatus Manfio, Jorge & Ribeiro-Costa sp. nov. is described from the Amazon basin in Brazil (Acre) and Ecuador (Napo), and is included in an updated key to the species of Gibbobruchus Pic. This new species and the recently described G. bergamini Manfio & Ribeiro-Costa are incorporated into a phylogenetic reanalysis of the genus and into a comparative analysis of host plant use and biogeography. Species groups previously proposed were supported and the evolutionary history in host plant-use shows Gibbobruchus conserved at tribe level, Cercideae (Caesalpinioideae), with coordination between biogeographic expansion and host genus shifts. Both species, Gibbobruchus tridentatus Manfio, Jorge & Ribeiro-Costa sp. nov. and G. bergamini, were placed within the group scurra (G. tridentatus (G. scurra (G. cavillator+G. bolivianus+G. bergamini))) and supported by one synapomorphy. Additionally, we update geographic distributions and host plant records. Two hosts, Bauhinia argentinensis Burkart and B. tarapotensis Benth. are recorded for the first time as hosts for the genus and for the subfamily.

First Record of Transversotrema Witenberg, 1944 (Digenea) from the Americas, with Comments on the Taxonomy of Transversotrema patialense (Soparkar, 1924) Crusz and Sathananthan, 1960, and an Updated List of Its Hosts and Geographic Distribution.

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Womble, Matthew R; Cox-Gardiner, Stephanie J; Cribb, Thomas H; Bullard, Stephen A

2015-12-01

Specimens of Transversotrema patialense (sensu lato) ( Soparkar, 1924 ) Crusz and Sathananthan, 1960 (Digenea: Transversotrematidae) infected the skin (epidermal spaces beneath scales near pectoral fins) of 4 of 126 (prevalence 3%; mean intensity 1.8) zebrafish ( Danio rerio (Hamilton, 1822) [Cypriniformes: Cyprinidae]) purchased in 2009 and cultured by a California (USA) fish supplier. These fish were sold as "laboratory-reared" and "specific pathogen free," purportedly raised in a recirculating aquaculture system that included zebrafish only. We herein describe the morphological features of this transversotrematid using light and scanning electron microscopy, provide a comprehensive list of hosts (snails and fishes) and geographic locality records for specimens reported as T. patialense, which is perhaps a species complex, and provide a brief historical synopsis of the taxonomic and life history research that has been conducted on this fluke. No species of Transversotrema previously had been reported from the Americas; however, this discovery is not surprising given that: (1) a suitable intermediate host (red-rimmed melania, Melanoides tuberculata (Müller, 1774) [Cerithioidea: Thiaridae]) has been established in California and elsewhere in North America, (2) the zebrafish is a susceptible definitive host, and (3) T. patialense reportedly matures on a broad ecological and phylogenetic spectrum of freshwater fishes. To our knowledge, this is the northern-most geographic locality record for a species of this genus. We suspect this case study represents an example of a parasite that may now be established in North America by the fortuitous co-occurrence of a susceptible, exotic snail host (the red-rimmed melania) and a susceptible, widely distributed, exotic fish host (the zebrafish).

Epidemiology, species distribution, antifungal susceptibility and outcome of candidemia among Internal Medicine Wards of community hospitals of Udine province, Italy

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Federico Silvestri

2014-09-01

Full Text Available Candidemia is an emerging problem among patients hospitalized in Internal Medicine Wards (IMW. We performed a retrospective study to assess the epidemiology, species distribution, antifungal susceptibility and outcome of candidaemia recorded over a 3-year period (2010-2012 among IMW of community hospitals of Udine province in Italy: forty-eight patients were identified, with an overall incidence of 1.44 cases/1000 hospital admissions/year. Candida albicans was the most frequent species, followed by Candida parapsilosis that accounted for 42.9% of Tolmezzo cases. All isolates were susceptible to amphotericin and caspofungin, while 11.4% of strains were not-susceptible to voriconazole and 14.3% to fluconazole. Crude mortality was 41.7%. In conclusion, in community hospitals overall incidence of candidemia is similar to tertiary care hospitals, but 80% of cases are detected in IMW. Candida species distribution is overlapping, but differences in local epidemiology were found and should be taken into consideration. No resistance to amphotericin and caspofungin was found while resistance to azoles was observed. Knowledge of this data might be useful when planning the best therapeutic strategy.

Persistence of functional protein domains in mycoplasma species and their role in host specificity and synthetic minimal life

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Kamminga, Tjerko; Koehorst, Jasper J.; Vermeij, Paul; Slagman, Simen Jan; Santos, dos Vitor A.P.M.; Bijlsma, Jetta J.E.; Schaap, Peter J.

2017-01-01

Mycoplasmas are the smallest self-replicating organisms and obligate parasites of a specific vertebrate host. An in-depth analysis of the functional capabilities of mycoplasma species is fundamental to understand how some of simplest forms of life on Earth succeeded in subverting complex hosts with

PHI-base: a new interface and further additions for the multi-species pathogen–host interactions database

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Urban, Martin; Cuzick, Alayne; Rutherford, Kim; Irvine, Alistair; Pedro, Helder; Pant, Rashmi; Sadanadan, Vidyendra; Khamari, Lokanath; Billal, Santoshkumar; Mohanty, Sagar; Hammond-Kosack, Kim E.

2017-01-01

The pathogen–host interactions database (PHI-base) is available at www.phi-base.org. PHI-base contains expertly curated molecular and biological information on genes proven to affect the outcome of pathogen–host interactions reported in peer reviewed research articles. In addition, literature that indicates specific gene alterations that did not affect the disease interaction phenotype are curated to provide complete datasets for comparative purposes. Viruses are not included. Here we describe a revised PHI-base Version 4 data platform with improved search, filtering and extended data display functions. A PHIB-BLAST search function is provided and a link to PHI-Canto, a tool for authors to directly curate their own published data into PHI-base. The new release of PHI-base Version 4.2 (October 2016) has an increased data content containing information from 2219 manually curated references. The data provide information on 4460 genes from 264 pathogens tested on 176 hosts in 8046 interactions. Prokaryotic and eukaryotic pathogens are represented in almost equal numbers. Host species belong ∼70% to plants and 30% to other species of medical and/or environmental importance. Additional data types included into PHI-base 4 are the direct targets of pathogen effector proteins in experimental and natural host organisms. The curation problems encountered and the future directions of the PHI-base project are briefly discussed. PMID:27915230

Baseline susceptibility to pyrethroid and organophosphate insecticides in two old world sand fly species (diptera: psychodidae)

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A study was conducted with support from the Department of Defense’s Deployed Warfighter Protection (DWFP) Program to evaluate the susceptibility of two old world sand fly species, Phlebotomus papatasi and P. duboscqi, to a number of commonly used pyrethroid and organophosphate insecticides. A simpl...

Host-Feeding Patterns of Culex stigmatosoma (Diptera: Culicidae) in Southern California.

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McPhatter, Lee P; Su, Tianyun; Williams, Greg; Cheng, Min-Lee; Dhillon, Major; Gerry, Alec C

2017-11-07

Knowledge of the blood-feeding patterns exhibited by arthropod vectors is essential for understanding the complex dynamics of vector-borne disease transmission. Some species of mosquitoes belonging to the genus Culex have been implicated as having major roles in the transmission of arboviruses such as West Nile virus, Saint Louis encephalitis virus, and Western equine encephalitis virus. Although the host-feeding patterns for many of these Culex species are well studied, the host-feeding patterns of Culex stigmatosoma Dyar are relatively poorly studied, even though this species is suspected to be an important maintenance vector for West Nile virus and other arboviruses. In the current study, bloodmeals from 976 blood-engorged Cx. stigmatosoma, collected from 30 sites in southern California from 2009-2012, were processed for vertebrate host identification by nucleotide sequencing following polymerase chain reaction to amplify portions of the cytochrome oxidase I and cytochrome b genes of vertebrate animals. Vertebrate DNA was amplified, sequenced, and identified from a total of 647 Cx. stigmatosoma bloodmeals, revealing that 98.6% of bloodmeals were from birds, 1.2% from three mammal species, and a single bloodmeal was from a reptile species. In total, 40 different host species were identified. The greatest number of bloodmeals identified was from domestic chicken (Gallus gallus domesticus L.) (38% of bloodmeals), house sparrow (Passer domesticus L.) (23%), house finch (Haemorhous mexicanus Müller) (17%), American crow (Corvus brachyrhynchos L.) (4%), and mourning dove (Zenaida macroura L.) (3%). However, chicken bloodmeals were identified almost entirely from a single site where mosquito collection devices were placed in the near vicinity of confined domestic chickens. The strongly ornithophilic feeding behavior shown in this study for Cx. stigmatosoma supports the hypothesis that this mosquito species may be an important maintenance (or endemic) vector for

Cuticle Fatty Acid Composition and Differential Susceptibility of Three Species of Cockroaches to the Entomopathogenic Fungi Metarhizium anisopliae (Ascomycota, Hypocreales).

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Gutierrez, Alejandra C; Gołębiowski, Marek; Pennisi, Mariana; Peterson, Graciela; García, Juan J; Manfrino, Romina G; López Lastra, Claudia C

2015-04-01

Differences in free fatty acids (FFAs) chemical composition of insects may be responsible for susceptibility or resistance to fungal infection. Determination of FFAs found in cuticular lipids can effectively contribute to the knowledge concerning insect defense mechanisms. In this study, we have evaluated the susceptibility of three species of cockroaches to the entomopathogenic fungi Metarhizium anisopliae (Metschnikoff) Sorokin by topical application. Mortality due to M. anisopliae was highly significant on adults and nymphs of Blattella germanica L. (Blattodea: Blattellidae). However, mortality was faster in adults than in nymphs. Adults of Blatta orientalis L. (Blattodea: Blattidae) were not susceptible to the fungus, and nymphs of Blaptica dubia Serville (Blattodea: Blaberidae) were more susceptible to the fungus than adults. The composition of cuticular FFAs in the three species of cockroaches was also studied. The analysis indicated that all of the fatty acids were mostly straight-chain, long-chain, saturated or unsaturated. Cuticular lipids of three species of cockroaches contained 19 FFAs, ranging from C14:0 to C24:0. The predominant fatty acids found in the three studied species of cockroaches were oleic, linoleic, palmitic, and stearic acid. Only in adults of Bl. orientalis, myristoleic acid, γ-linolenic acid, arachidic acid, dihomolinoleic acid, and behenic acid were identified. Lignoceric acid was detected only in nymphs of Bl. orientalis. Heneicosylic acid and docosahexaenoic acid were identified in adults of Ba. dubia. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Babesia, Theileria, and Hepatozoon species in ticks infesting animal hosts in Romania.

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Andersson, Martin O; Tolf, Conny; Tamba, Paula; Stefanache, Mircea; Radbea, Gabriel; Rubel, Franz; Waldenström, Jonas; Dobler, Gerhard; Chițimia-Dobler, Lidia

2017-08-01

Babesia spp., Theileria spp., and Hepatozoon spp. are tick-transmitted apicomplexan parasites that cause several important diseases in animals. To increase current knowledge about the diversity of tick-transmitted pathogens in Romania, we investigated the occurrence of Babesia spp., Theileria spp., and Hepatozoon spp. in a wide range of tick species infesting animal hosts. We collected 852 ticks from 10 different animal species from 20 counties in Romania. The assessment was based on detection of parasite DNA by PCR. Five different apicomplexan parasite species were detected; among them three different species of Babesia: B. canis, B. microti, and B. ovis. Hepatozoon canis was the most frequently detected parasite, found predominately in Ixodes ricinus ticks collected from domestic dogs. It was also detected in I. ricinus collected from goat, fox, and cat. Furthermore, H. canis was found in Haemaphysalis punctata and Haemaphysalis concinna ticks. In addition, Theileria buffeli was detected in Rhipicephalus bursa ticks collected from cattle.

Prevalence and antimicrobial susceptibility profile of listeria species from ready-to-eat foods of animal origin in Gondar Town, Ethiopia.

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Garedew, Legesse; Taddese, Ayele; Biru, Tigist; Nigatu, Seleshe; Kebede, Elias; Ejo, Mebrat; Fikru, Abraham; Birhanu, Tamiru

2015-05-12

Listeriosis, mostly caused by Listeria monocytogenes species, has become a major concern to public health authorities due to its clinical severity and high mortality rate, particularly in high risk groups. Currently, there is limited information regarding the prevalence and antimicrobial susceptibility profiles of listeria species in ready-to-eat foods of animal origin in Gondar town, Ethiopia. The aim of this study was to determine the prevalence and antimicrobial susceptibility pattern of Listeria species isolated from ready-to-eat food of animal origin from public dinning places in Gondar town, Ethiopia. A cross sectional study on ready-toeat foods of animal origin sampled from major supermarkets, butcher shops, pastry shops, restaurants and hotels was carried out. Culture, biochemical and sugar tests were conducted for listeria species identification and disc diffusion test was performed to study the antimicrobial susceptibility profiles of the isolates. Out of 384 food samples examined, 96 (25%) were positive for Listeria species. Listeria monocytogenes was detected in 24 (6.25%) of the samples. Listeria monocytogenes was isolated from cake, raw meat, ice cream, minced beef, fish, unpasteurized milk and pizza in that order from higher to lower rate. Assessment of antimicrobial susceptibility profile of L. monocytogenes revealed the presence of four multi-drug resistant isolates. The higher resistance rate was recorded for penicillin, nalidixic acid, tetracycline and chloramphenicol, in decreasing order. All L. monocytogenes identified in the current study were sensitive to amoxicillin, cephalothin, cloxacillin, sulfamethoxazole, gentamicin and vancomycin. The presence of L. monocytogenes including drug resistant and multidrug resistant isolates in some ready-to-eat food items is an indicator of the presence of public health hazards to the consumer, particularly to the high-risk groups. Hence awareness creation on food safety and implementation of regulations

Host sharing and host manipulation by larval helminths in shore crabs: cooperation or conflict?

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Poulin, Robert; Nichol, Katherine; Latham, A David M

2003-04-01

Larval helminths of different species that share the same intermediate host and are transmitted by predation to the same definitive host may cooperate in their attempts to manipulate the behaviour of the intermediate host, while at the same time having conflicts of interests over the use of host resources. A few studies have indicated that intermediate hosts harbouring larval helminths have altered concentrations of neurotransmitters in their nervous system, and thus measuring levels of neurotransmitters in host brains could serve to assess the respective and combined effect of different helminth species on host behaviour. Here, we investigate potential cooperation and conflict among three helminths in two species of crab intermediate hosts. The acanthocephalan Profilicollis spp., the trematode Maritrema sp. and an acuariid nematode, all use Macrophthalmus hirtipes (Ocypodidae) as intermediate host, whereas Profilicollis and Maritrema also use Hemigrapsus crenulatus (Grapsidae). All three helminths mature inside gulls or other shore birds. There was a significant decrease in the mean volume of Profilicollis cystacanths as the intensity of infection by this parasite increased in H. crenulatus, the only host in which this was investigated; however, there was no measurable effect of other helminth species on the size of acanthocephalans, suggesting no interspecific conflict over resource use within crabs. There was, in contrast, evidence of a positive interspecific association between the two most common helminth species: numbers of Profilicollis and Maritrema were positively correlated among crabs, independently of crab size, in M. hirtipes but not H. crenulatus. More importantly, we found that the total number of larval helminths per crab correlated significantly, and negatively, with concentrations of serotonin in crab brains, again only in M. hirtipes; numbers of each parasite species separately did not covary in either crab species with serotonin or dopamine, the

Experimental evolution of an RNA virus in wild birds: evidence for host-dependent impacts on population structure and competitive fitness.

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Nathan D Grubaugh

2015-05-01

Full Text Available Within hosts, RNA viruses form populations that are genetically and phenotypically complex. Heterogeneity in RNA virus genomes arises due to error-prone replication and is reduced by stochastic and selective mechanisms that are incompletely understood. Defining how natural selection shapes RNA virus populations is critical because it can inform treatment paradigms and enhance control efforts. We allowed West Nile virus (WNV to replicate in wild-caught American crows, house sparrows and American robins to assess how natural selection shapes RNA virus populations in ecologically relevant hosts that differ in susceptibility to virus-induced mortality. After five sequential passages in each bird species, we examined the phenotype and population diversity of WNV through fitness competition assays and next generation sequencing. We demonstrate that fitness gains occur in a species-specific manner, with the greatest replicative fitness gains in robin-passaged WNV and the least in WNV passaged in crows. Sequencing data revealed that intrahost WNV populations were strongly influenced by purifying selection and the overall complexity of the viral populations was similar among passaged hosts. However, the selective pressures that control WNV populations seem to be bird species-dependent. Specifically, crow-passaged WNV populations contained the most unique mutations (~1.7× more than sparrows, ~3.4× more than robins and defective genomes (~1.4× greater than sparrows, ~2.7× greater than robins, but the lowest average mutation frequency (about equal to sparrows, ~2.6× lower than robins. Therefore, our data suggest that WNV replication in the most disease-susceptible bird species is positively associated with virus mutational tolerance, likely via complementation, and negatively associated with the strength of selection. These differences in genetic composition most likely have distinct phenotypic consequences for the virus populations. Taken together

Plant Killing by Mutualistic Ants Increases the Density of Host Species Seedlings in the Dry Forest of Costa Rica

OpenAIRE

Amador-Vargas, Sabrina

2012-01-01

Some species of plant-mutualistic ants kill the vegetation growing in the vicinities of their host plant, creating an area of bare ground (clearing). The reduced competition in the clearing may facilitate the establishment of host species sprouts (clones and seedlings), which in turn benefits the ants with additional food and shelter (“sprout-establishment hypothesis”). To test this hypothesis, the density and origin of Acacia collinsii sprouts growing inside clearings and in the vicinities o...

Reciprocal Hosts' Responses to Powdery Mildew Isolates Originating from Domesticated Wheats and Their Wild Progenitor.

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Ben-David, Roi; Dinoor, Amos; Peleg, Zvi; Fahima, Tzion

2018-01-01

The biotroph wheat powdery mildew, Blumeria graminis (DC.) E.O. Speer, f. sp. tritici Em. Marchal ( Bgt ), has undergone long and dynamic co-evolution with its hosts. In the last 10,000 years, processes involved in plant evolution under domestication, altered host-population structure. Recently both virulence and genomic profiling separated Bgt into two groups based on their origin from domestic host and from wild emmer wheat. While most studies focused on the Bgt pathogen, there is significant knowledge gaps in the role of wheat host diversity in this specification. This study aimed to fill this gap by exploring qualitatively and also quantitatively the disease response of diverse host panel to powdery mildew [105 domesticated wheat genotypes ( Triticum turgidum ssp. dicoccum, T. turgidum ssp. durum , and T. aestivum ) and 241 accessions of its direct progenitor, wild emmer wheat ( T. turgidum ssp. dicoccoides )]. A set of eight Bgt isolates, originally collected from domesticated and wild wheat was used for screening this wheat collection. The isolates from domesticated wheat elicited susceptible to moderate plant responses on domesticated wheat lines and high resistance on wild genotypes (51.7% of the tested lines were resistant). Isolates from wild emmer elicited reciprocal disease responses: high resistance of domesticated germplasm and high susceptibility of the wild material (their original host). Analysis of variance of the quantitative phenotypic responses showed a significant Isolates × Host species interaction [ P (F) < 0.0001] and further supported these findings. Furthermore, analysis of the range of disease severity values showed that when the group of host genotypes was inoculated with Bgt isolate from the reciprocal host, coefficient of variation was significantly higher than when inoculated with its own isolates. This trend was attributed to the role of major resistance genes in the latter scenario (high proportion of complete resistance). By

Reciprocal Hosts' Responses to Powdery Mildew Isolates Originating from Domesticated Wheats and Their Wild Progenitor

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Roi Ben-David

2018-02-01

Full Text Available The biotroph wheat powdery mildew, Blumeria graminis (DC. E.O. Speer, f. sp. tritici Em. Marchal (Bgt, has undergone long and dynamic co-evolution with its hosts. In the last 10,000 years, processes involved in plant evolution under domestication, altered host-population structure. Recently both virulence and genomic profiling separated Bgt into two groups based on their origin from domestic host and from wild emmer wheat. While most studies focused on the Bgt pathogen, there is significant knowledge gaps in the role of wheat host diversity in this specification. This study aimed to fill this gap by exploring qualitatively and also quantitatively the disease response of diverse host panel to powdery mildew [105 domesticated wheat genotypes (Triticum turgidum ssp. dicoccum, T. turgidum ssp. durum, and T. aestivum and 241 accessions of its direct progenitor, wild emmer wheat (T. turgidum ssp. dicoccoides]. A set of eight Bgt isolates, originally collected from domesticated and wild wheat was used for screening this wheat collection. The isolates from domesticated wheat elicited susceptible to moderate plant responses on domesticated wheat lines and high resistance on wild genotypes (51.7% of the tested lines were resistant. Isolates from wild emmer elicited reciprocal disease responses: high resistance of domesticated germplasm and high susceptibility of the wild material (their original host. Analysis of variance of the quantitative phenotypic responses showed a significant Isolates × Host species interaction [P(F < 0.0001] and further supported these findings. Furthermore, analysis of the range of disease severity values showed that when the group of host genotypes was inoculated with Bgt isolate from the reciprocal host, coefficient of variation was significantly higher than when inoculated with its own isolates. This trend was attributed to the role of major resistance genes in the latter scenario (high proportion of complete resistance. By

An Aphid Effector Targets Trafficking Protein VPS52 in a Host-Specific Manner to Promote Virulence.

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Rodriguez, Patricia A; Escudero-Martinez, Carmen; Bos, Jorunn I B

2017-03-01

Plant- and animal-feeding insects secrete saliva inside their hosts, containing effectors, which may promote nutrient release and suppress immunity. Although for plant pathogenic microbes it is well established that effectors target host proteins to modulate host cell processes and promote disease, the host cell targets of herbivorous insects remain elusive. Here, we show that the existing plant pathogenic microbe effector paradigm can be extended to herbivorous insects in that effector-target interactions inside host cells modify critical host processes to promote plant susceptibility. We showed that the effector Mp1 from Myzus persicae associates with the host Vacuolar Protein Sorting Associated Protein52 (VPS52). Using natural variants, we provide a strong link between effector virulence activity and association with VPS52, and show that the association is highly specific to M persicae -host interactions. Also, coexpression of Mp1, but not Mp1-like variants, specifically with host VPS52s resulted in effector relocalization to vesicle-like structures that associate with prevacuolar compartments. We show that high VPS52 levels negatively impact virulence, and that aphids are able to reduce VPS52 levels during infestation, indicating that VPS52 is an important virulence target. Our work is an important step forward in understanding, at the molecular level, how a major agricultural pest promotes susceptibility during infestation of crop plants. We give evidence that an herbivorous insect employs effectors that interact with host proteins as part of an effective virulence strategy, and that these effectors likely function in a species-specific manner. © 2017 American Society of Plant Biologists. All Rights Reserved.

Genetic and morphological diversity of Trisetacus species (Eriophyoidea: Phytoptidae) associated with coniferous trees in Poland: phylogeny, barcoding, host and habitat specialization.

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Lewandowski, Mariusz; Skoracka, Anna; Szydło, Wiktoria; Kozak, Marcin; Druciarek, Tobiasz; Griffiths, Don A

2014-08-01

Eriophyoid species belonging to the genus Trisetacus are economically important as pests of conifers. A narrow host specialization to conifers and some unique morphological characteristics have made these mites interesting subjects for scientific inquiry. In this study, we assessed morphological and genetic variation of seven Trisetacus species originating from six coniferous hosts in Poland by morphometric analysis and molecular sequencing of the mitochondrial cytochrome oxidase subunit I gene and the nuclear D2 region of 28S rDNA. The results confirmed the monophyly of the genus Trisetacus as well as the monophyly of five of the seven species studied. Both DNA sequences were effective in discriminating between six of the seven species tested. Host-dependent genetic and morphological variation in T. silvestris and T. relocatus, and habitat-dependent genetic and morphological variation in T. juniperinus were detected, suggesting the existence of races or even distinct species within these Trisetacus taxa. This is the first molecular phylogenetic analysis of the Trisetacus species. The findings presented here will stimulate further investigations on the evolutionary relationships of Trisetacus as well as the entire Phytoptidae family.

Sporadic Creutzfeldt-Jakob Disease: Prion Pathology in Medulla Oblongata-Possible Routes of Infection and Host Susceptibility.

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Iacono, Diego; Ferrari, Sergio; Gelati, Matteo; Zanusso, Gianluigi; Mariotto, Sara; Monaco, Salvatore

2015-01-01

Sporadic Creutzfeldt-Jakob disease (sCJD), the most frequent human prion disorder, is characterized by remarkable phenotypic variability, which is influenced by the conformation of the pathologic prion protein and the methionine/valine polymorphic codon 129 of the prion protein gene. While the etiology of sCJD remains unknown, it has been hypothesized that environmental exposure to prions might occur through conjunctival/mucosal contact, oral ingestion, inhalation, or simultaneous involvement of the olfactory and enteric systems. We studied 21 subjects with definite sCJD to assess neuropathological involvement of the dorsal motor nucleus of the vagus and other medullary nuclei and to evaluate possible associations with codon 129 genotype and prion protein conformation. The present data show that prion protein deposition was detected in medullary nuclei of distinct sCJD subtypes, either valine homozygous or heterozygous at codon 129. These findings suggest that an "environmental exposure" might occur, supporting the hypothesis that external sources of contamination could contribute to sCJD in susceptible hosts. Furthermore, these novel data could shed the light on possible causes of sCJD through a "triple match" hypothesis that identify environmental exposure, host genotype, and direct exposure of specific anatomical regions as possible pathogenetic factors.

Insecticide susceptibility of Nezara viridula (Heteroptera: Pentatomidae) and three other stink bug species composing a soybean pest complex in Japan.

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Takeuchi, Hiroaki; Endo, Nobuyuki

2012-06-01

The susceptibility of the stink bug species Nezara viridula (L.), Nezara antennata Scott, Piezodorus hybneri (Gmelin), and Riptortus pedestris (F.) to insecticides was tested, establishing their 50% lethal dose (LD50) values as baseline data. Third instars and adults of the four species were treated by topical application with seven insecticides: fenitrothion, fenthion, etofenprox, silafluofen, dinotefuran, clothianidin, and ethiprole. The weight of the stink bug and weight of the insecticide applied to each bug were used as explanatory variables in the probit regression analysis. The effect of the body weight on the dose-response relationship, the proportional model, was not uniform among the tested insecticide-stink bug combinations. However, the basic model fit all combinations and could estimate LD50 values successfully. Therefore, LD50 values at the medium (average) weight estimated by the basic model were selected to describe the susceptibility of the stink bugs. The LD50 value of silafluofen for N. viridula adults, and that of silafluofen and etofenprox for N. antennata adults, was at least 2,338 ng greater than the other species exposed to each insecticide. Almost all of the LD50 values for adults were over 10 times greater than those of the same species' nymphs treated with the same insecticide. Thus monitoring of occurring species and their developmental stages is important for controlling effectively the stink bug pest complex by insecticides, especially by silafluofen or etofenprox. The estimated LD50 values can be used as baseline data to compare the susceptibility of the species collected in another year or location.

Repeated Schistosoma japonicum infection following treatment in two cohorts: evidence for host susceptibility to helminthiasis?

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Elizabeth J Carlton

Full Text Available In light of multinational efforts to reduce helminthiasis, we evaluated whether there exist high-risk subpopulations for helminth infection. Such individuals are not only at risk of morbidity, but may be important parasite reservoirs and appropriate targets for disease control interventions.We followed two longitudinal cohorts in Sichuan, China to determine whether there exist persistent human reservoirs for the water-borne helminth, Schistosoma japonicum, in areas where treatment is ongoing. Participants were tested for S. japonicum infection at enrollment and two follow-up points. All infections were promptly treated with praziquantel. We estimated the ratio of the observed to expected proportion of the population with two consecutive infections at follow-up. The expected proportion was estimated using a prevalence-based model and, as highly exposed individuals may be most likely to be repeatedly infected, a second model that accounted for exposure using a data adaptive, machine learning algorithm. Using the prevalence-based model, there were 1.5 and 5.8 times more individuals with two consecutive infections than expected in cohorts 1 and 2, respectively (p<0.001 in both cohorts. When we accounted for exposure, the ratio was 1.3 (p = 0.013 and 2.1 (p<0.001 in cohorts 1 and 2, respectively.We found clustering of infections within a limited number of hosts that was not fully explained by host exposure. This suggests some hosts may be particularly susceptible to S. japonicum infection, or that uncured infections persist despite treatment. We propose an explanatory model that suggests that as cercarial exposure declines, so too does the size of the vulnerable subpopulation. In low-prevalence settings, interventions targeting individuals with a history of S. japonicum infection may efficiently advance disease control efforts.

Species-specific identification of equine cyathostomes resistant to fenbendazole and susceptible to oxibendazole and moxidectin by macroarray probing.

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Traversa, Donato; Iorio, Raffaella; Otranto, Domenico; Giangaspero, Annunziata; Milillo, Piermarino; Klei, Thomas R

2009-01-01

Cyathostome populations in horses on two farms located in central Italy with a history of fenbendazole (FBZ) resistance were investigated with the Faecal Egg Count Reduction Test to evaluate the susceptibility to oxibendazole and moxidectin. Faecal eggs were collected pre- and post-treatment on each farm and molecularly examined with a Reverse Line Blot (RLB) assay able to unequivocally detect and identify 13 cyathostome species. Resistance to FBZ was confirmed on both farms, while oxibendazole and moxidectin demonstrated 97% and 100% efficacy, respectively. Overall eight species of cyathostomes (Coronocyclus labiatus, Cylicocyclus ashworthi, Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicostephanus calicatus and Cylicocyclus insigne) were identified in pre-treatment samples. Coronocyclus labiatus and C. goldi were identified after treatment with FBZ while C. calicatus and C. labiatus were shown to be <100% susceptible to oxibendazole. These data confirm that resistance to benzimidazoles is established in cyathostome populations from horse farms in Italy and that they are susceptible to moxidectin. The oxibendazole has been successfully demonstrated for the first time as effective against Italian populations of cyathostomes resistant to other benzimidazoles. The RLB assay herein used showed to be useful to study the distribution of these parasitic populations at species level under field conditions and could represent a powerful tool in broader investigation of drug resistance in horse farms from several countries.

An Aphid Effector Targets Trafficking Protein VPS52 in a Host-Specific Manner to Promote Virulence1[OPEN

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2017-01-01

Plant- and animal-feeding insects secrete saliva inside their hosts, containing effectors, which may promote nutrient release and suppress immunity. Although for plant pathogenic microbes it is well established that effectors target host proteins to modulate host cell processes and promote disease, the host cell targets of herbivorous insects remain elusive. Here, we show that the existing plant pathogenic microbe effector paradigm can be extended to herbivorous insects in that effector-target interactions inside host cells modify critical host processes to promote plant susceptibility. We showed that the effector Mp1 from Myzus persicae associates with the host Vacuolar Protein Sorting Associated Protein52 (VPS52). Using natural variants, we provide a strong link between effector virulence activity and association with VPS52, and show that the association is highly specific to M. persicae-host interactions. Also, coexpression of Mp1, but not Mp1-like variants, specifically with host VPS52s resulted in effector relocalization to vesicle-like structures that associate with prevacuolar compartments. We show that high VPS52 levels negatively impact virulence, and that aphids are able to reduce VPS52 levels during infestation, indicating that VPS52 is an important virulence target. Our work is an important step forward in understanding, at the molecular level, how a major agricultural pest promotes susceptibility during infestation of crop plants. We give evidence that an herbivorous insect employs effectors that interact with host proteins as part of an effective virulence strategy, and that these effectors likely function in a species-specific manner. PMID:28100451

Susceptibility to Phytophthora ramorum and inoculum production potential of some common eastern forest understory plant species

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Paul W. Tooley; Marsha Browning

2009-01-01

Twenty-five plant species (21 genera, 14 families), which comprise a portion of the understory in forests of the Eastern United States, were evaluated for susceptibility to infection by Phytophthora ramorum. The degree to which P. ramorum is able to form sporangia and chlamydospores was also assessed on...

Establishment of Myotis myotis cell lines--model for investigation of host-pathogen interaction in a natural host for emerging viruses.

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Xiaocui He

Full Text Available Bats are found to be the natural reservoirs for many emerging viruses. In most cases, severe clinical signs caused by such virus infections are normally not seen in bats. This indicates differences in the virus-host interactions and underlines the necessity to develop natural host related models to study these phenomena. Due to the strict protection of European bat species, immortalized cell lines are the only alternative to investigate the innate anti-virus immune mechanisms. Here, we report about the establishment and functional characterization of Myotis myotis derived cell lines from different tissues: brain (MmBr, tonsil (MmTo, peritoneal cavity (MmPca, nasal epithelium (MmNep and nervus olfactorius (MmNol after immortalization by SV 40 large T antigen. The usefulness of these cell lines to study antiviral responses has been confirmed by analysis of their susceptibility to lyssavirus infection and the mRNA patterns of immune-relevant genes after poly I:C stimulation. Performed experiments indicated varying susceptibility to lyssavirus infection with MmBr being considerably less susceptible than the other cell lines. Further investigation demonstrated a strong activation of interferon mediated antiviral response in MmBr contributing to its resistance. The pattern recognition receptors: RIG-I and MDA5 were highly up-regulated during rabies virus infection in MmBr, suggesting their involvement in promotion of antiviral responses. The presence of CD14 and CD68 in MmBr suggested MmBr cells are microglia-like cells which play a key role in host defense against infections in the central nervous system (CNS. Thus the expression pattern of MmBr combined with the observed limitation of lyssavirus replication underpin a protective mechanism of the CNS controlling the lyssavirus infection. Overall, the established cell lines are important tools to analyze antiviral innate immunity in M. myotis against neurotropic virus infections and present a valuable

Establishment of Myotis myotis cell lines--model for investigation of host-pathogen interaction in a natural host for emerging viruses.

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He, Xiaocui; Korytář, Tomáš; Zhu, Yaqing; Pikula, Jiří; Bandouchova, Hana; Zukal, Jan; Köllner, Bernd

2014-01-01

Bats are found to be the natural reservoirs for many emerging viruses. In most cases, severe clinical signs caused by such virus infections are normally not seen in bats. This indicates differences in the virus-host interactions and underlines the necessity to develop natural host related models to study these phenomena. Due to the strict protection of European bat species, immortalized cell lines are the only alternative to investigate the innate anti-virus immune mechanisms. Here, we report about the establishment and functional characterization of Myotis myotis derived cell lines from different tissues: brain (MmBr), tonsil (MmTo), peritoneal cavity (MmPca), nasal epithelium (MmNep) and nervus olfactorius (MmNol) after immortalization by SV 40 large T antigen. The usefulness of these cell lines to study antiviral responses has been confirmed by analysis of their susceptibility to lyssavirus infection and the mRNA patterns of immune-relevant genes after poly I:C stimulation. Performed experiments indicated varying susceptibility to lyssavirus infection with MmBr being considerably less susceptible than the other cell lines. Further investigation demonstrated a strong activation of interferon mediated antiviral response in MmBr contributing to its resistance. The pattern recognition receptors: RIG-I and MDA5 were highly up-regulated during rabies virus infection in MmBr, suggesting their involvement in promotion of antiviral responses. The presence of CD14 and CD68 in MmBr suggested MmBr cells are microglia-like cells which play a key role in host defense against infections in the central nervous system (CNS). Thus the expression pattern of MmBr combined with the observed limitation of lyssavirus replication underpin a protective mechanism of the CNS controlling the lyssavirus infection. Overall, the established cell lines are important tools to analyze antiviral innate immunity in M. myotis against neurotropic virus infections and present a valuable tool for a

Establishment of Myotis myotis Cell Lines - Model for Investigation of Host-Pathogen Interaction in a Natural Host for Emerging Viruses

Science.gov (United States)

He, Xiaocui; Korytář, Tomáš; Zhu, Yaqing; Pikula, Jiří; Bandouchova, Hana; Zukal, Jan; Köllner, Bernd

2014-01-01

Bats are found to be the natural reservoirs for many emerging viruses. In most cases, severe clinical signs caused by such virus infections are normally not seen in bats. This indicates differences in the virus-host interactions and underlines the necessity to develop natural host related models to study these phenomena. Due to the strict protection of European bat species, immortalized cell lines are the only alternative to investigate the innate anti-virus immune mechanisms. Here, we report about the establishment and functional characterization of Myotis myotis derived cell lines from different tissues: brain (MmBr), tonsil (MmTo), peritoneal cavity (MmPca), nasal epithelium (MmNep) and nervus olfactorius (MmNol) after immortalization by SV 40 large T antigen. The usefulness of these cell lines to study antiviral responses has been confirmed by analysis of their susceptibility to lyssavirus infection and the mRNA patterns of immune-relevant genes after poly I:C stimulation. Performed experiments indicated varying susceptibility to lyssavirus infection with MmBr being considerably less susceptible than the other cell lines. Further investigation demonstrated a strong activation of interferon mediated antiviral response in MmBr contributing to its resistance. The pattern recognition receptors: RIG-I and MDA5 were highly up-regulated during rabies virus infection in MmBr, suggesting their involvement in promotion of antiviral responses. The presence of CD14 and CD68 in MmBr suggested MmBr cells are microglia-like cells which play a key role in host defense against infections in the central nervous system (CNS). Thus the expression pattern of MmBr combined with the observed limitation of lyssavirus replication underpin a protective mechanism of the CNS controlling the lyssavirus infection. Overall, the established cell lines are important tools to analyze antiviral innate immunity in M. myotis against neurotropic virus infections and present a valuable tool for a

PHI-base: a new interface and further additions for the multi-species pathogen-host interactions database.

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Urban, Martin; Cuzick, Alayne; Rutherford, Kim; Irvine, Alistair; Pedro, Helder; Pant, Rashmi; Sadanadan, Vidyendra; Khamari, Lokanath; Billal, Santoshkumar; Mohanty, Sagar; Hammond-Kosack, Kim E

2017-01-04

The pathogen-host interactions database (PHI-base) is available at www.phi-base.org PHI-base contains expertly curated molecular and biological information on genes proven to affect the outcome of pathogen-host interactions reported in peer reviewed research articles. In addition, literature that indicates specific gene alterations that did not affect the disease interaction phenotype are curated to provide complete datasets for comparative purposes. Viruses are not included. Here we describe a revised PHI-base Version 4 data platform with improved search, filtering and extended data display functions. A PHIB-BLAST search function is provided and a link to PHI-Canto, a tool for authors to directly curate their own published data into PHI-base. The new release of PHI-base Version 4.2 (October 2016) has an increased data content containing information from 2219 manually curated references. The data provide information on 4460 genes from 264 pathogens tested on 176 hosts in 8046 interactions. Prokaryotic and eukaryotic pathogens are represented in almost equal numbers. Host species belong ∼70% to plants and 30% to other species of medical and/or environmental importance. Additional data types included into PHI-base 4 are the direct targets of pathogen effector proteins in experimental and natural host organisms. The curation problems encountered and the future directions of the PHI-base project are briefly discussed. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Effects of host nutrition on virulence and fitness of entomopathogenic nematodes: Lipid- and protein-based supplements in Tenebrio molitor diets

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Shapiro-Ilan, David; Rojas, M. Guadalupe; Morales-Ramos, Juan A.; Lewis, Edwin E.; Tedders, W. Louis

2008-01-01

Entomopathogenic nematodes, Heterorhabditis indica and Steinernema riobrave, were tested for virulence and reproductive yield in Tenebrio molitor that were fed wheat bran diets with varying lipid- and protein-based supplements. Lipid supplements were based on 20% canola oil, peanut, pork or salmon, or a low lipid control (5% canola). Protein treatments consisted of basic supplement ingredients plus 0, 10, or 20% egg white; a bran-only control was also included. Some diet supplements had positive effects on nematode quality, whereas others had negative or neutral effects. All supplements with 20% lipids except canola oil caused increased T. molitor susceptibility to H. indica, whereas susceptibility to S. riobrave was not affected. Protein supplements did not affect host susceptibility, and neither lipid nor protein diet supplements affected reproductive capacity of either nematode species. Subsequently, we determined the pest control efficacy of progeny of nematodes that had been reared through T. molitor from different diets against Diaprepes abbreviatus and Otiorhynchus sulcatus. All nematode treatments reduced insect survival relative to the control (water only). Nematodes originating from T. molitor diets with the 0% or 20% protein exhibited lower efficacy versus D. abbreviatus than the intermediate level of protein (10%) or bran-only treatments. Nematodes originating from T. molitor lipid or control diets did not differ in virulence. Our research indicates that nutritional content of an insect host diet can affect host susceptibility to entomopathogenic nematodes and nematode fitness; therefore, host media could conceivably be optimized to increase in vivo nematode production efficiency. PMID:19259513

Interspecies Variation in the Susceptibility of a Wild-Derived Colony of Mice to Pinworms (Aspiculuris tetraptera).

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Curtis, Ryan C; Murray, Jill K; Campbell, Polly; Nagamori, Yoko; Molnar, Adam; Jackson, Todd A

2017-01-01

Pinworms are common parasites in wild and laboratory rodents. Despite their relative nonpathogenicity in immunocompetent models, pinworm infections add an unwanted variable and may confound some types of research. For this reason, health monitoring programs and biosecurity measures aim to minimize the spread of pinworm infections into colonies free from the organisms. Wild-derived and laboratory strains of mice have shown varied susceptibility to infection with Aspiculuris tetraptera, the most commonly found murine pinworm. In particular, susceptibility is increased in wild-derived mice, young animals, and males. Routine surveillance at our institution revealed pinworm infection (A. tetraptera only) within a colony of multiple, wild-derived species of Mus, although only specific species showed positive results during initial sampling. To assess whether species-associated differences in susceptibility were present, we analyzed fecal egg counts of A. tetraptera in every cage of the colony. Our results revealed significant differences in susceptibility between various species and subspecies of Mus. Egg counts were significantly higher in Mus spicilegus than Mus m. domesticus (WSB/EiJ) and Mus macedonicus. Mus spretus had higher egg counts than M. m. domesticus (WSB/EiJ), M. m. musculus (PWK/PhJ), and M. macedonicus. Egg counts did not differ in regard to age, sex, or number of mice per cage. As wild-derived mouse models continue to compliment research largely based on laboratory strains, it will be important to understand host-parasite interactions and their effects on research, particularly studies evaluating immune responses, behavior, growth, and other physiologic parameters.

Species distribution and in vitro fluconazole susceptibility of clinical Candida isolates in a Brazilian tertiary-care hospital over a 3-year period

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Márcia Cristina Furlaneto

2011-10-01

Full Text Available INTRODUCTION: In this study, we aimed at identifying Candida isolates obtained from blood, urine, tracheal secretion, and nail/skin lesions from cases attended at the Hospital Universitário de Londrina over a 3-year period and at evaluating fluconazole susceptibilities of the isolates. METHODS: Candida isolates were identified by polymerase chain reaction (PCR using species-specific forward primers. The in vitro fluconazole susceptibility test was performed according to EUCAST-AFST reference procedure. RESULTS: Isolates were obtained from urine (53.4%, blood cultures (19.2%, tracheal secretion (17.8%, and nail/skin lesions (9.6%. When urine samples were considered, prevalence was similar in women (45.5% and in men (54.5% and was high in the age group >61 years than that in younger ones. For blood samples, prevalence was high in neonates (35% and advanced ages (22.5%. For nail and skin samples, prevalence was higher in women (71.4% than in men (28.6%. Candida albicans was the most frequently isolated in the hospital, but Candida species other than C. albicans accounted for 64% of isolates, including predominantly Candida tropicalis (33.2% and Candida parapsilosis (19.2%. The trend for non-albicans Candida as the predominant species was noted from all clinical specimens, except from urine samples. All Candida isolates were considered susceptible in vitro to fluconazole with the exception of isolates belonging to the intrinsically less-susceptible species C. glabrata. CONCLUSIONS: Non-albicans Candida species were more frequently isolated in the hospital. Fluconazole resistance was a rare finding in our study.

The vaginal microbiota, host defence and reproductive physiology.

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Smith, Steven B; Ravel, Jacques

2017-01-15

The interaction between the human host and the vaginal microbiota is highly dynamic. Major changes in the vaginal physiology and microbiota over a woman's lifetime are largely shaped by transitional periods such as puberty, menopause and pregnancy, while daily fluctuations in microbial composition observed through culture-independent studies are more likely to be the results of daily life activities and behaviours. The vaginal microbiota of reproductive-aged women is largely made up of at least five different community state types. Four of these community state types are dominated by lactic-acid producing Lactobacillus spp. while the fifth is commonly composed of anaerobes and strict anaerobes and is sometimes associated with vaginal symptoms. The production of lactic acid has been associated with contributing to the overall health of the vagina due to its direct and indirect effects on pathogens and host defence. Some species associated with non-Lactobacillus vaginal microbiota may trigger immune responses as well as degrade the host mucosa, processes that ultimately increase susceptibility to infections and contribute to negative reproductive outcomes such as infertility and preterm birth. Further studies are needed to better understand the functional underpinnings of how the vaginal microbiota affect host physiology but also how host physiology affects the vaginal microbiota. Understanding this fine-tuned interaction is key to maintaining women's reproductive health. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

The vaginal microbiota, host defence and reproductive physiology

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Smith, Steven B

2016-01-01

Abstract The interaction between the human host and the vaginal microbiota is highly dynamic. Major changes in the vaginal physiology and microbiota over a woman's lifetime are largely shaped by transitional periods such as puberty, menopause and pregnancy, while daily fluctuations in microbial composition observed through culture‐independent studies are more likely to be the results of daily life activities and behaviours. The vaginal microbiota of reproductive‐aged women is largely made up of at least five different community state types. Four of these community state types are dominated by lactic‐acid producing Lactobacillus spp. while the fifth is commonly composed of anaerobes and strict anaerobes and is sometimes associated with vaginal symptoms. The production of lactic acid has been associated with contributing to the overall health of the vagina due to its direct and indirect effects on pathogens and host defence. Some species associated with non‐Lactobacillus vaginal microbiota may trigger immune responses as well as degrade the host mucosa, processes that ultimately increase susceptibility to infections and contribute to negative reproductive outcomes such as infertility and preterm birth. Further studies are needed to better understand the functional underpinnings of how the vaginal microbiota affect host physiology but also how host physiology affects the vaginal microbiota. Understanding this fine‐tuned interaction is key to maintaining women's reproductive health. PMID:27373840

Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize.

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Jordaan, E M; De Waele, D

1988-10-01

The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae.

The Effects of Aphid Traits on Parasitoid Host Use and Specialist Advantage

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Gagic, Vesna; Petrović-Obradović, Olivera; Fründ, Jochen; Kavallieratos, Nickolas G.; Athanassiou, Christos G.; Starý, Petr; Tomanović, Željko

2016-01-01

Specialization is a central concept in ecology and one of the fundamental properties of parasitoids. Highly specialized parasitoids tend to be more efficient in host-use compared to generalized parasitoids, presumably owing to the trade-off between host range and host-use efficiency. However, it remains unknown how parasitoid host specificity and host-use depends on host traits related to susceptibility to parasitoid attack. To address this question, we used data from a 13-year survey of interactions among 142 aphid and 75 parasitoid species in nine European countries. We found that only aphid traits related to local resource characteristics seem to influence the trade-off between host-range and efficiency: more specialized parasitoids had an apparent advantage (higher abundance on shared hosts) on aphids with sparse colonies, ant-attendance and without concealment, and this was more evident when host relatedness was included in calculation of parasitoid specificity. More traits influenced average assemblage specialization, which was highest in aphids that are monophagous, monoecious, large, highly mobile (easily drop from a plant), without myrmecophily, habitat specialists, inhabit non-agricultural habitats and have sparse colonies. Differences in aphid wax production did not influence parasitoid host specificity and host-use. Our study is the first step in identifying host traits important for aphid parasitoid host specificity and host-use and improves our understanding of bottom-up effects of aphid traits on aphid-parasitoid food web structure. PMID:27309729

Host specificity and genealogy of the louse Polyplax serrata on field mice, Apodemus species: a case of parasite duplication or colonisation?

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Stefka, Jan; Hypsa, Václav

2008-05-01

The genealogy, population structure and population dynamics of the sucking louse Polyplax serrata were analysed across four host species of the genus Apodemus. An analysis of 126 sequences of cytochrome c oxidase subunit I using phylogenetic approaches and haplotype networking revealed a clear structure of European samples, forming three distinct and genetically distant clades with different host specificities. Although a clear connection was detected between the host and parasite genealogies/phylogenies, a uniform pattern of co-speciation was not found. For example, a dramatic shift in the degree of host specificity was demonstrated for two related louse lineages living in sympatry and sharing one of their host species. While one of the louse lineages frequently parasitised two different host taxa (Apodemus sylvaticus and Apodemus flavicollis), the other louse lineage was strictly specific to A. flavicollis. The estimate of divergence time between the two louse lineages indicates that they may have arisen due to parasite duplication on A. flavicollis.

Identification and antifungal susceptibility of Candida species isolated from the urine of patients in a university hospital in Brazil

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Gláucia Moreira Espíndola Lima

2017-12-01

Full Text Available ABSTRACT The aim of this study was to identify Candida spp. isolated from candiduria episodes at a tertiary hospital in the Midwest region of Brazil, and to determine their susceptibility profiles to antifungal compounds. From May 2011 to April 2012, Candida spp. isolated from 106 adult patients with candiduria admitted to the University Hospital of the Federal University of Mato Grosso do Sul were evaluated. Both, species identification and susceptibility testing with fluconazole-FLC, voriconazole-VRC, and amphotericin B-AmB were carried out using the Vitek 2. To discriminate species of the C. parapsilosis complex, a RAPD-PCR technique using the RPO2 primer was performed. From the total of 106 isolates, 42 (39.6% C. albicans and 64 (60.4% Candida non-albicans (CNA - 33 C. tropicalis, 18 C. glabrata, 5 C. krusei, 4 C. parapsilosis sensu stricto, 2 C. kefyr, 1 C. lusitaniae, and 1 C. guilliermondii were identified. All isolates were susceptible to AmB and VRC, whereas all C. glabrata isolates presented either resistance (5.6% or dose-dependent susceptibility (94.4% to FLC. The study of Candida spp. and their resistance profiles may help in tailoring more efficient therapeutic strategies for candiduria.

Mud crab susceptibility to disease from white spot syndrome virus is species-dependent

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Sritunyalucksana Kallaya

2010-11-01

Full Text Available Abstract Background Based on a report for one species (Scylla serrata, it is widely believed that mud crabs are relatively resistant to disease caused by white spot syndrome virus (WSSV. We tested this hypothesis by determining the degree of susceptibility in two species of mud crabs, Scylla olivacea and Scylla paramamosain, both of which were identified by mitochondrial 16 S ribosomal gene analysis. We compared single-dose and serial-dose WSSV challenges on S. olivacea and S. paramamosain. Findings In a preliminary test using S. olivacea alone, a dose of 1 × 106 WSSV copies/g gave 100% mortality within 7 days. In a subsequent test, 17 S. olivacea and 13 S. paramamosain were divided into test and control groups for challenge with WSSV at 5 incremental, biweekly doses starting from 1 × 104 and ending at 5 × 106 copies/g. For 11 S. olivacea challenged, 3 specimens died at doses between 1 × 105 and 5 × 105 copies/g and none died for 2 weeks after the subsequent dose (1 × 106 copies/g that was lethal within 7 days in the preliminary test. However, after the final challenge on day 56 (5 × 106 copies/g, the remaining 7 of 11 S. olivacea (63.64% died within 2 weeks. There was no mortality in the buffer-injected control crabs. For 9 S. paramamosain challenged in the same way, 5 (55.56% died after challenge doses between 1 × 104 and 5 × 105 copies/g, and none died for 2 weeks after the challenge dose of 1 × 106 copies/g. After the final challenge (5 × 106 copies/g on day 56, no S. paramamosain died during 2 weeks after the challenge, and 2 of 9 WSSV-infected S. paramamosain (22.22% remained alive together with the control crabs until the end of the test on day 106. Viral loads in these survivors were low when compared to those in the moribund crabs. Conclusions S. olivacea and S. paramamosain show wide variation in response to challenge with WSSV. S. olivacea and S. paramamosain are susceptible to white spot disease, and S. olivacea is more

Susceptibility of eastern water dragons Intellagama lesueurii lesueurii to Bohle iridovirus.

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Maclaine, A; Mashkour, N; Scott, J; Ariel, E

2018-01-31

Ranaviruses infect and have been associated with mass mortality events in fish, amphibians and reptiles and are capable of interclass transmission. Eastern water dragons (EWDs), a semi-aquatic squamate, have an overlapping distribution with several species shown to be susceptible to Bohle iridovirus (BIV). However, this species has not been previously investigated, and no known mass mortalities have occurred in wild populations. Here we report the experimental infection of juvenile EWDs with BIV to investigate a water-dwelling lizards' susceptibility to a ranaviral strain present in northern Queensland, Australia. Lizards were exposed via oral inoculation, intramuscular injection, or cohabitation with orally infected lizards. All exposure methods were effective in establishing an infection as demonstrated by skin lesions and pathological changes in the internal organs. Necrosis, haemorrhage and inflammation were observed histologically in the pancreas, liver, spleen, kidney and submucosa of the gastrointestinal tract of BIV-exposed lizards. Variably sized basophilic intracytoplasmic inclusion bodies were observed in the liver of 6/14 BIV-exposed lizards. Virus was isolated from the liver and kidney of all BIV-infected lizards and confirmed with quantitative PCR (qPCR). The outcome of this study demonstrates that juvenile EWDs are susceptible to BIV, thereby adding Australian lizards to the broad host range of ranaviruses. Furthermore, this study provides additional evidence of BIV's ability to infect different classes of ecothermic vertebrates.

Fish population studies using parasites from the Southeastern Pacific Ocean: considering host population changes and species body size as sources of variability of parasite communities.

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George-Nascimento, Mario; Oliva, Marcelo

2015-01-01

Research using parasites in fish population studies in the South Eastern Pacific (SEP) is summarized. There are 27 such studies (snapshots mainly) in single host species sampled at different geographic localities and at somewhat similar times. They have been devoted mainly to economically important species, though others on coastal and intertidal fish or on less- or non-commercial species provide insights on scales of temporal and spatial variation of parasite infracommunities. Later, we assess whether the probability of harbouring parasites depends on the host species body size. Our results indicate that a stronger tool for fish population studies may be developed under regular (long term) scrutiny of parasite communities, especially of small fish host species, due to their larger variability in richness, abundance and total biomass, than in large fish species. Finally, it might also be necessary to consider the effects of fishing on parasite communities as well as the natural oscillations (coupled or not) of host and parasite populations.

Wildly Growing Asparagus (Asparagus officinalis L.) Hosts Pathogenic Fusarium Species and Accumulates Their Mycotoxins.

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Stępień, Łukasz; Waśkiewicz, Agnieszka; Urbaniak, Monika

2016-05-01

Asparagus officinalis L. is an important crop in many European countries, likely infected by a number of Fusarium species. Most of them produce mycotoxins in plant tissues, thus affecting the physiology of the host plant. However, there is lack of information on Fusarium communities in wild asparagus, where they would definitely have considerable environmental significance. Therefore, the main scientific aim of this study was to identify the Fusarium species and quantify their typical mycotoxins present in wild asparagus plants collected at four time points of the season. Forty-four Fusarium strains of eight species--Fusarium acuminatum, Fusarium avenaceum, Fusarium culmorum, Fusarium equiseti, Fusarium oxysporum, Fusarium proliferatum, Fusarium sporotrichioides, and Fusarium tricinctum--were isolated from nine wild asparagus plants in 2013 season. It is the first report of F. sporotrichioides isolated from this particular host. Fumonisin B1 was the most abundant mycotoxin, and the highest concentrations of fumonisins B1-B3 and beauvericin were found in the spears collected in May. Moniliformin and enniatins were quantified at lower concentrations. Mycotoxins synthesized by individual strains obtained from infected asparagus tissues were assessed using in vitro cultures on sterile rice grain. Most of the F. sporotrichioides strains synthesized HT-2 toxin and F. equiseti strains were found to be effective zearalenone producers.

Antibiotic susceptibility of body surface and gut micro flora of two aquatic leech species (Hirudinaria manillensis and Hirudinaria javanica in Malaysia

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Parimannan Sivachandran

2013-08-01

Full Text Available Objective: To elucidate the antibiotic susceptibility of body surface and gut associated microflora of two local aquatic leech species Hirudinaria manillensis and Hirudinaria javanica. Methods: Four commercially available antibiotics (doxycycline, chloramphenicol, tetracycline and ciprofloxacin were used in this study. A total of 13 isolated gut and two surface micro flora from Hirudinaria manillensis and two gut and two surface micro flora from Hirudinaria javanica were tested for their antibiotic susceptibility. Results: Based on the susceptibility, it was observed that all the isolated bacteria were found to be susceptible to at least three of the antibiotics except Microbacterium resistens, Serratia marcescens and Morganella morganii. This study also found that the bacterial species Bacillus fusiformis has displayed resistance against tetracycline and Tsukamurella inchonensis against chloramphenicol. Conclusions: Among all the antibiotics tested, ciprofloxacin was found to be the best bactericidal agent. The immersion of leeches in ciprofloxacin before the application to the patient may be beneficial to prevent invasive infection of the patient. Further study is needed to sterilize the live leech by immersion/oral mode of administration for the tested antibiotics.

Etest and Sensititre YeastOne Susceptibility Testing of Echinocandins against Candida Species from a Single Center in Austria.

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Aigner, Maria; Erbeznik, Thomas; Gschwentner, Martin; Lass-Flörl, Cornelia

2017-08-01

Candida species were tested for susceptibility to caspofungin, anidulafungin, and micafungin in order to evaluate the roles of Etest and Sensititre YeastOne in antifungal susceptibility testing for daily routines and to survey resistance. A total of 104 Candida species isolates detected from blood cultures were investigated. With EUCAST broth microdilution as the reference method, essential agreement (EA), categorical agreement (CA), very major errors (VME), major errors (ME), and minor (MIN) errors were assessed by reading MICs at 18, 24, and 48 h. By use of EUCAST broth microdilution and species-specific clinical breakpoints (CBPs), echinocandin resistance was not detected during the study period. Using EUCAST CBPs, MIC readings at 24 h for the Etest and Sensititre YeastOne resulted in CA levels of 99% and 93% for anidulafungin and 99% and 97% for micafungin. Using revised CLSI CBPs for caspofungin, CA levels were 92% and 99% for Etest and Sensititre YeastOne. The Etest proved an excellent, easy-to-handle alternative method for testing susceptibility to anidulafungin and micafungin. Due to misclassifications, the Etest is less suitable for testing susceptibility to caspofungin (8% of isolates falsely tested resistant). The CA levels of Sensititre YeastOne were 93% and 97% for anidulafungin and micafungin (24 h) by use of EUCAST CBPs and increased to 100% for both antifungals if CLSI CBPs were applied and to 100% and 99% if Sensititre YeastOne epidemiological cutoff values (ECOFFs) were applied. No one echinocandin could be demonstrated to be superior to another in vitro Since resistance was lacking among our Candida isolates, we cannot derive any recommendation from accurate resistance detection by the Etest and Sensititre YeastOne. Copyright © 2017 American Society for Microbiology.

Historical biogeography among species of Varestrongylus lungworms (Nematoda: Protostrongylidae) in ungulates: episodic expansion and host colonization linking Eurasia and North America.

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Verocai, Guilherme G; Kutz, Susan J; Hoberg, Eric P

2018-05-03

Varestrongylus lungworms (Nematoda: Protostrongylidae) include 10 nominal species that parasitize wild and domesticated artiodactyles. Eight species are endemic to the western Palearctic and Eurasia, whereas two are limited in distribution to the Nearctic. Complex host associations, primarily among Cervidae and Bovidae (Caprinae), and biogeography were explored based on direct comparisons of parasite and host phylogenies to reveal the historical development of this fauna. Diversification among Varestrongylus species has an intricate history extending over the Pliocene and Quaternary involving episodic processes for geographic and host colonization: (1) Varestrongylus has origins in Eurasia with independent expansion events into bordering ecozones; (2) cervids are ancestral hosts; (3) the caprine-associated V. pneumonicus is basal and a result of an independent host colonization event; (4) secondary diversification, linked to sequential and independent host colonization events, occurred within cervids (V. sagittatus + V. tuvae; V. alpenae; and V. capreoli, V. alces + V. eleguneniensis); (5) at least two additional host colonization events into caprines occurred, followed or not by diversification (V. qinghaiensis + V. longispiculatus; V. capricola, respectively); (6) two independent events of geographic expansion into North America from Eurasia with cervids in the late Pliocene and early Pleistocene are postulated (V. alpenae, V. eleguneniensis). Comparisons based on phylogenetic hypotheses derived from comparative morphology and molecular inference for these nematodes are consistent with the postulated history for coevolutionary and biogeographic history. Episodes of geographic and host colonization, often in relation to rapid shifts in climate and habitat perturbation, have dominated the history of diversification of Varestrongylus.

Ecology and Life Cycle Patterns of Echinococcus Species.

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Romig, T; Deplazes, P; Jenkins, D; Giraudoux, P; Massolo, A; Craig, P S; Wassermann, M; Takahashi, K; de la Rue, M

2017-01-01

The genus Echinococcus is composed of eight generally recognized species and one genotypic cluster (Echinococcus canadensis cluster) that may in future be resolved into one to three species. For each species, we review existing information on transmission routes and life cycles in different geographical contexts and - where available - include basic biological information of parasites and hosts (e.g., susceptibility of host species). While some Echinococcus spp. are transmitted in life cycles that involve predominantly domestic animals (e.g., dog - livestock cycles), others are wildlife parasites that do or do not interact with domestic transmission. In many cases, life cycle patterns of the same parasite species differ according to geography. Simple life cycles contrast with transmission patterns that are highly complex, involving multihost systems that may include both domestic and wild mammals. Wildlife transmission may be primary or secondary, i.e., resulting from spillovers from domestic animals. For most of the species and regions, existing information does not yet permit a conclusive description of transmission systems. Such data, however, would be highly relevant, e.g., for anticipation of geographical changes of the presence and frequency of these parasites in a warming world, or for initiating evidence-based control strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

The ethnobotanical, phytochemical and mineral analyses of phragmanthera incana (klotzsch), a species of mistletoe growing on three plant hosts in South-Western Nigeria.

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Ogunmefun, O T; Fasola, T R; Saba, A B; Oridupa, O A

2013-03-01

Mistletoe is collected wildly on various plants and Phragmanthera incana is noted to grow on different plant hosts. This study was designed to carry out the ethnobotanical survey, phytochemical and mineral analyses of Phragmanthera incana, a species of mistletoe growing on three plant hosts namely Cocoa (Theobroma cacao), Kolanut (Cola nitida) and Bush mango (Irvingia gabonensis). Mistletoe samples were identified at the Forestry Research Institute of Nigeria Herbarium. Phragmanthera incana was screened for its phytochemical constituents and mineral cations along its hosts following standard methods and to confirm if the mistletoe species is host specific. The powdered samples of the mistletoe species (Phragmanthera incana) was used for both the phytochemical screening and the cation mineral analysis. The uses and the harvesting methods of mistletoe were also reviewed extensively in this paper.

Identifying the Achilles heel of multi-host pathogens: the concept of keystone ‘host’ species illustrated by Mycobacterium ulcerans transmission

International Nuclear Information System (INIS)

Roche, Benjamin; Eric Benbow, M; Merritt, Richard; Kimbirauskas, Ryan; McIntosh, Mollie; Small, Pamela L C; Williamson, Heather; Guégan, Jean-François

2013-01-01

Pathogens that use multiple host species are an increasing public health issue due to their complex transmission, which makes them difficult to mitigate. Here, we explore the possibility of using networks of ecological interactions among potential host species to identify the particular disease-source species to target to break down transmission of such pathogens. We fit a mathematical model on prevalence data of Mycobacterium ulcerans in western Africa and we show that removing the most abundant taxa for this category of pathogen is not an optimal strategy to decrease the transmission of the mycobacterium within aquatic ecosystems. On the contrary, we reveal that the removal of some taxa, especially Oligochaeta worms, can clearly reduce rates of pathogen transmission, and these should be considered as keystone organisms for its transmission because they lead to a substantial reduction in pathogen prevalence regardless of the network topology. Besides their potential application for the understanding of M. ulcerans ecology, we discuss how networks of species interactions can modulate transmission of multi-host pathogens. (letter)

Profiling of Leptospira interrogans, L. santarosai, L. meyeri and L. borgpetersenii by SE-AFLP, PFGE and susceptibility testing--a continuous attempt at species and serovar differentiation.

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Moreno, Luisa Z; Miraglia, Fabiana; Lilenbaum, Walter; Neto, José S F; Freitas, Julio C; Morais, Zenaide M; Hartskeerl, Rudy A; da Costa, Barbara L P; Vasconcellos, Silvio A; Moreno, Andrea M

2016-03-09

Leptospirosis is a widespread systemic zoonosis, considered as reemerging in certain developing countries. Although the cross agglutinin absorption test is still considered the standard method for Leptospira identification, it presents several disadvantages. The aim of this study was to characterize Leptospira spp. isolated from various hosts by genotyping and broth microdilution susceptibility testing in an attempt to differentiate Leptospira species, serogroups and serovars. Forty-seven isolates were studied. They were previously serotyped, and species confirmation was performed by 16S rRNA sequencing. Single-enzyme amplified fragment length polymorphism (SE-AFLP) and pulsed-field gel electrophoresis (PFGE) analysis enabled the distinction of L. interrogans from L. santarosai, L. meyeri and L. borgpetersenii in two main clusters. Among L. interrogans, it was possible to differentiate into two new clusters the serogroup Icterohaemorrhagiae from the serogroups Canicola and Pomona. L. santarosai isolates presented higher genetic variation than the other species in both techniques. Interestingly, the minimum inhibitory concentration (MIC) cluster analysis also provided Leptospira serogroup differentiation. Further studies are necessary regarding serovar Bananal isolates, as they presented the highest MIC values for most of the antimicrobials tested. All studied techniques successfully distinguished Leptospira species and serogroups. Despite being library-dependent methods, these approaches are less labor intensive and more economically viable, particularly SE-AFLP, and can be implemented in most reference laboratories worldwide to enable faster Leptospira typing.

OAS1 polymorphisms are associated with susceptibility to West Nile encephalitis in horses.

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Jonathan J Rios

Full Text Available West Nile virus, first identified within the United States in 1999, has since spread across the continental states and infected birds, humans and domestic animals, resulting in numerous deaths. Previous studies in mice identified the Oas1b gene, a member of the OAS/RNASEL innate immune system, as a determining factor for resistance to West Nile virus (WNV infection. A recent case-control association study described mutations of human OAS1 associated with clinical susceptibility to WNV infection. Similar studies in horses, a particularly susceptible species, have been lacking, in part, because of the difficulty in collecting populations sufficiently homogenous in their infection and disease states. The equine OAS gene cluster most closely resembles the human cluster, with single copies of OAS1, OAS3 and OAS2 in the same orientation. With naturally occurring susceptible and resistant sub-populations to lethal West Nile encephalitis, we undertook a case-control association study to investigate whether, similar to humans (OAS1 and mice (Oas1b, equine OAS1 plays a role in resistance to severe WNV infection. We identified naturally occurring single nucleotide mutations in equine (Equus caballus OAS1 and RNASEL genes and, using Fisher's Exact test, we provide evidence that mutations in equine OAS1 contribute to host susceptibility. Virtually all of the associated OAS1 polymorphisms were located within the interferon-inducible promoter, suggesting that differences in OAS1 gene expression may determine the host's ability to resist clinical manifestations associated with WNV infection.

Environmental factors regulate Paneth cell phenotype and host susceptibility to intestinal inflammation in Irgm1-deficient mice

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Allison R. Rogala

2018-02-01

Full Text Available Crohn's disease (CD represents a chronic inflammatory disorder of the intestinal tract. Several susceptibility genes have been linked to CD, though their precise role in the pathogenesis of this disorder remains unclear. Immunity-related GTPase M (IRGM is an established risk allele in CD. We have shown previously that conventionally raised (CV mice lacking the IRGM ortholog, Irgm1 exhibit abnormal Paneth cells (PCs and increased susceptibility to intestinal injury. In the present study, we sought to utilize this model system to determine if environmental conditions impact these phenotypes, as is thought to be the case in human CD. To accomplish this, wild-type and Irgm1−/− mice were rederived into specific pathogen-free (SPF and germ-free (GF conditions. We next assessed how these differential housing environments influenced intestinal injury patterns, and epithelial cell morphology and function in wild-type and Irgm1−/− mice. Remarkably, in contrast to CV mice, SPF Irgm1−/− mice showed only a slight increase in susceptibility to dextran sodium sulfate-induced inflammation. SPF Irgm1−/− mice also displayed minimal abnormalities in PC number and morphology, and in antimicrobial peptide expression. Goblet cell numbers and epithelial proliferation were also unaffected by Irgm1 in SPF conditions. No microbial differences were observed between wild-type and Irgm1−/− mice, but gut bacterial communities differed profoundly between CV and SPF mice. Specifically, Helicobacter sequences were significantly increased in CV mice; however, inoculating SPF Irgm1−/− mice with Helicobacter hepaticus was not sufficient to transmit a pro-inflammatory phenotype. In summary, our findings suggest the impact of Irgm1-deficiency on susceptibility to intestinal inflammation and epithelial function is critically dependent on environmental influences. This work establishes the importance of Irgm1−/− mice as a model to elucidate host

Understanding regulation of the host-mediated gut symbiont population and the symbiont-mediated host immunity in the Riptortus-Burkholderia symbiosis system.

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Kim, Jiyeun Kate; Lee, Jun Beom; Jang, Ho Am; Han, Yeon Soo; Fukatsu, Takema; Lee, Bok Luel

2016-11-01

Valuable insect models have tremendously contributed to our understanding of innate immunity and symbiosis. Bean bug, Riptortus pedestris, is a useful insect symbiosis model due to harboring cultivable monospecific gut symbiont, genus Burkholderia. Bean bug is a hemimetabolous insect whose immunity is not well-understood. However, we recently identified three major antimicrobial peptides of Riptortus and examined the relationship between gut symbiosis and host immunity. We found that the presence of Burkholderia gut symbiont positively affects Riptortus immunity. From studying host regulation mechanisms of symbiont population, we revealed that the symbiotic Burkholderia cells are much more susceptible to Riptortus immune responses than the cultured cells. We further elucidated that the immune-susceptibility of the Burkholderia gut symbionts is due to the drastic change of bacterial cell envelope. Finally, we show that the immune-susceptible Burkholderia symbionts are able to prosper in host owing to the suppression of immune responses of the symbiotic midgut. Copyright © 2016 Elsevier Ltd. All rights reserved.

Susceptibility and molecular characterization of Candida species from patients with vulvovaginitis

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Gheniffer Fornari

2016-06-01

Full Text Available Abstract Vulvovaginal candidiasis affects women of reproductive age, which represents approximately 15–25% of vaginitis cases. The present study aimed to isolate and characterize yeast from the patients irrespective of the presentation of clinical symptoms. The isolates were subjected to in vitro susceptibility profile and characterization by molecular markers, which intended to assess the distribution of species. A total of 40 isolates were obtained and identified through the CHROMagar, API20aux and by ITS and D1/D2 regions sequencing of DNAr gene. Candida albicans strains were genotyped by the ABC system and the isolates were divided into two genotypic groups. The identity of the C. albicans, C. glabrata, C. guilliermondii, C. kefyr and Saccharomyces cerevisiae isolates was confirmed by the multilocus analysis. The strains of Candida, isolated from patients with complications, were found to be resistant to nystatin but sensitive to fluconazole, amphotericin B and ketoconazole, as observed by in vitro sensitivity profile. The isolates from asymptomatic patients, i.e., the colonized group, showed a dose-dependent sensitivity to the anti-fungal agents, fluconazole and amphotericin B. However, the isolates of C. albicans that belong to distinct genotypic groups showed the same in vitro susceptibility profile.

Susceptibility and molecular characterization of Candida species from patients with vulvovaginitis.

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Fornari, Gheniffer; Vicente, Vania Aparecida; Gomes, Renata Rodrigues; Muro, Marisol Dominguez; Pinheiro, Rosangela Lameira; Ferrari, Carolina; Herkert, Patricia Fernanda; Takimura, Marcos; Carvalho, Newton Sérgio de; Queiroz-Telles, Flavio

2016-01-01

Vulvovaginal candidiasis affects women of reproductive age, which represents approximately 15-25% of vaginitis cases. The present study aimed to isolate and characterize yeast from the patients irrespective of the presentation of clinical symptoms. The isolates were subjected to in vitro susceptibility profile and characterization by molecular markers, which intended to assess the distribution of species. A total of 40 isolates were obtained and identified through the CHROMagar, API20aux and by ITS and D1/D2 regions sequencing of DNAr gene. Candida albicans strains were genotyped by the ABC system and the isolates were divided into two genotypic groups. The identity of the C. albicans, C. glabrata, C. guilliermondii, C. kefyr and Saccharomyces cerevisiae isolates was confirmed by the multilocus analysis. The strains of Candida, isolated from patients with complications, were found to be resistant to nystatin but sensitive to fluconazole, amphotericin B and ketoconazole, as observed by in vitro sensitivity profile. The isolates from asymptomatic patients, i.e., the colonized group, showed a dose-dependent sensitivity to the anti-fungal agents, fluconazole and amphotericin B. However, the isolates of C. albicans that belong to distinct genotypic groups showed the same in vitro susceptibility profile. Copyright © 2016. Published by Elsevier Editora Ltda.

Helminth community structure in two species of arctic-breeding waterfowl

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C.L. Amundson

2016-12-01

Full Text Available Climate change is occurring rapidly at high latitudes, and subsequent changes in parasite communities may have implications for hosts including wildlife and humans. Waterfowl, in particular, harbor numerous parasites and may facilitate parasite movement across broad geographic areas due to migratory movements. However, little is known about helminth community structure of waterfowl at northern latitudes. We investigated the helminth communities of two avian herbivores that breed at high latitudes, Pacific black brant (Branta bernicla nigricans, and greater white-fronted geese (Anser albifrons, to examine effects of species, geographic area, age, and sex on helminth species richness, aggregation, prevalence, and intensity. We collected 83 and 58 black brant and white-fronted geese, respectively, from Arctic and Subarctic Alaska July–August 2014. We identified 10 known helminth species (Amidostomum anseris, Amidostomum spatulatum, Drepanidotaenia lanceolata, Epomidiostomum crami, Heterakis dispar, Notocotylus attenuatus, Tetrameres striata, Trichostrongylus tenuis, Tschertkovilepis setigera, and Wardoides nyrocae and 1 previously undescribed trematode. All geese sampled were infected with at least one helminth species. All helminth species identified were present in both age classes and species, providing evidence of transmission at high latitudes and suggesting broad host susceptibility. Also, all but one helminth species were present at both sites, suggesting conditions are suitable for transmission across a large latitudinal/environmental gradient. Our study provides important baseline information on avian parasites that can be used to evaluate the effects of a changing climate on host-parasite distributions.

Wild Cervids Are Host for Tick Vectors of Babesia Species with Zoonotic Capability in Belgium

OpenAIRE

Lempereur, Laetitia; Wirtgen, Marc; Nahayo, Adrien; Caron, Yannick; Shiels, Brian; Saegerman, Claude; Losson, Bertrand; Linden, Annick

2012-01-01

Babesiosis is a tick-borne disease caused by different species of intraerythrocytic protozoan parasites within the genus Babesia. Different species of Babesia are described as potentially zoonotic and cause a malaria-like disease mainly in immunocompromised humans. Interest in the zoonotic potential of Babesia is growing and babesiosis has been described by some authors as an emergent zoonotic disease. The role of cervids to maintain tick populations and act as a reservoir host for some Babes...

Genetic and morphological diversity of Trisetacus species (Eriophyoidea: Phytoptidae) associated with coniferous trees in Poland: phylogeny, barcoding, host and habitat specialization

OpenAIRE

Lewandowski, Mariusz; Skoracka, Anna; Szydło, Wiktoria; Kozak, Marcin; Druciarek, Tobiasz; Griffiths, Don A.

2014-01-01

Eriophyoid species belonging to the genus Trisetacus are economically important as pests of conifers. A narrow host specialization to conifers and some unique morphological characteristics have made these mites interesting subjects for scientific inquiry. In this study, we assessed morphological and genetic variation of seven Trisetacus species originating from six coniferous hosts in Poland by morphometric analysis and molecular sequencing of the mitochondrial cytochrome oxidase subunit I ge...

Lack of population genetic structure and host specificity in the bat fly, Cyclopodia horsfieldi, across species of Pteropus bats in Southeast Asia.

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Olival, Kevin J; Dick, Carl W; Simmons, Nancy B; Morales, Juan Carlos; Melnick, Don J; Dittmar, Katharina; Perkins, Susan L; Daszak, Peter; Desalle, Rob

2013-08-08

Population-level studies of parasites have the potential to elucidate patterns of host movement and cross-species interactions that are not evident from host genealogy alone. Bat flies are obligate and generally host-specific blood-feeding parasites of bats. Old-World flies in the family Nycteribiidae are entirely wingless and depend on their hosts for long-distance dispersal; their population genetics has been unstudied to date. We collected a total of 125 bat flies from three Pteropus species (Pteropus vampyrus, P. hypomelanus, and P. lylei) from eight localities in Malaysia, Cambodia, and Vietnam. We identified specimens morphologically and then sequenced three mitochondrial DNA gene fragments (CoI, CoII, cytB; 1744 basepairs total) from a subset of 45 bat flies. We measured genetic diversity, molecular variance, and population genetic subdivision (FST), and used phylogenetic and haplotype network analyses to quantify parasite genetic structure across host species and localities. All flies were identified as Cyclopodia horsfieldi with the exception of two individuals of Eucampsipoda sundaica. Low levels of population genetic structure were detected between populations of Cyclopodia horsfieldi from across a wide geographic range (~1000 km), and tests for isolation by distance were rejected. AMOVA results support a lack of geographic and host-specific population structure, with molecular variance primarily partitioned within populations. Pairwise FST values from flies collected from island populations of Pteropus hypomelanus in East and West Peninsular Malaysia supported predictions based on previous studies of host genetic structure. The lack of population genetic structure and morphological variation observed in Cyclopodia horsfieldi is most likely due to frequent contact between flying fox species and subsequent high levels of parasite gene flow. Specifically, we suggest that Pteropus vampyrus may facilitate movement of bat flies between the three Pteropus

Molecular and antimicrobial susceptibility profiling of atypical Streptococcus species from porcine clinical specimens.

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Moreno, Luisa Z; Matajira, Carlos E C; Gomes, Vasco T M; Silva, Ana Paula S; Mesquita, Renan E; Christ, Ana Paula G; Sato, Maria Inês Z; Moreno, Andrea M

2016-10-01

The Streptococcus species present broad phenotypic variation, making identification difficult using only traditional microbiological methods. Even though Streptococcus suis is the most important species for the worldwide swine industry, other Streptococcus species appear to be able to cause disease in swine and could represent a higher underestimated risk for porcine health. The aim of this study was to identify Streptococcus-like isolates by MALDI-TOF MS and 16S rRNA sequencing and further molecular and antibiotic susceptibility characterization of the atypical Streptococcus species capable of causing disease in swine. Fifty presumptive Streptococcus isolates from diseased pigs isolated from different Brazilian States between 2002 and 2014 were evaluated. Among the studied isolates, 26% were identified as Streptococcus hyovaginalis, 24% as Streptococcus plurianimalium, 12% as Streptococcus alactolyticus, 10% as Streptococcus hyointestinalis, and the remaining isolates belonged to Streptococcus henryi (6%), Streptococcus thoraltensis (6%), Streptococcus gallolyticus (6%), Streptococcus gallinaceus (4%), Streptococcus sanguinis (4%), and Streptococcus mitis (2%). The Streptococcus isolates were successfully identified by spectral cluster analysis and 16S rRNA sequencing with 96% of concordance between the techniques. The SE-AFLP analysis also supported Streptococcus species distinction and enabled further observation of higher genetic heterogeneity intra-species. The identified Streptococcus species presented variable MIC values to β-lactams, enrofloxacin and florfenicol, and high resistance rates to tetracyclines and macrolides, which appear to be directly related to the industry's antimicrobial usage and resistance selection. Copyright © 2016 Elsevier B.V. All rights reserved.

Prevalence and antimicrobial susceptibility of Ureaplasma species and Mycoplasma hominis in Greek female outpatients, 2012-2016.

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Maraki, Sofia; Mavromanolaki, Viktoria Eirini; Nioti, Eleni; Stafylaki, Dimitra; Minadakis, George

2017-11-28

Mycoplasma hominis and Ureaplasma species are opportunistic pathogens associated with urogenital infections, complications during pregnancy and postpartum infections. Appropriate empirical antimicrobial treatment is necessary to achieve an optimal therapeutic outcome. This study evaluated the prevalence and the antimicrobial susceptibility of Mycoplasma hominis and Ureaplasma spp. isolated from 1,008 endocervical samples of outpatients in Crete, Greece, during a five-year period (2012-2016), using the commercially available Mycoview kit (Zeakon diagnostics, France). Ureaplasma spp. was isolated from 116 patients (11.5%), M. hominis from 6 (0.6%), while coinfection with both mycoplasmas was demonstrated in 17 (1.7%). All Ureaplasma strains were susceptible to josamycin and doxycycline. Doxycycline, minocycline and ofloxacin were the most potent antibiotics against M. hominis. Docycycline was proved the most active and is still the drug of choice for the treatment of genital mycoplasma infections. Local surveillance to monitor changes in antimicrobial susceptibilities is necessary to guide treatment strategies.

Host specificity in bat ectoparasites: a natural experiment.

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Seneviratne, Sampath S; Fernando, H Chandrika; Udagama-Randeniya, Preethi V

2009-07-15

We undertook a field study to determine patterns of specialisation of ectoparasites in cave-dwelling bats in Sri Lanka. The hypothesis tested was that strict host specificity (monoxeny) could evolve through the development of differential species preferences through association with the different host groups. Three species of cave-dwelling bats were chosen to represent a wide range of host-parasite associations (monoxeny to polyxeny), and both sympatric and allopatric roosting assemblages. Of the eight caves selected, six caves were "allopatric" roosts where two of each housed only one of the three host species examined: Rousettus leschenaulti (Pteropodidae), Rhinolophus rouxi and Hipposideros speoris (Rhinolophidae). The remaining two caves were "sympatric" roosts and housed all three host species. Thirty bats of each species were examined for ectoparasites in each cave, which resulted in a collection of nycteribiid and streblid flies, an ischnopsyllid bat flea, argasid and ixodid ticks, and mites belonging to three families. The host specificity of bat parasites showed a trend to monoxeny in which 70% of the 30 species reported were monoxenous. Odds ratios derived from chi(2)-tests revealed two levels of host preferences in less-specific parasites (i) the parasite was found on two host species under conditions of both host sympatry and host allopatry, with a preference for a single host in the case of host sympatry and (ii) the preference for a single host was very high, hence under conditions of host sympatry, it was confined to the preferred host only. However, under conditions of host allopatry, it utilized both hosts. There appears to be an increasing prevalence in host preferences of the parasites toward confinement to a single host species. The ecological isolation of the bat hosts and a long history of host-parasite co-existence could have contributed to an overall tendency of bat ectoparasites to become specialists, here reflected in the high percentage

Species-Specific and Drug-Specific Differences in Susceptibility of Candida Biofilms to Echinocandins: Characterization of Less Common Bloodstream Isolates

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Simitsopoulou, Maria; Peshkova, Pavla; Tasina, Efthymia; Katragkou, Aspasia; Kyrpitzi, Daniela; Velegraki, Aristea; Walsh, Thomas J.

2013-01-01

Candida species other than Candida albicans are increasingly recognized as causes of biofilm-associated infections. This is a comprehensive study that compared the in vitro activities of all three echinocandins against biofilms formed by different common and infrequently identified Candida isolates. We determined the activities of anidulafungin (ANID), caspofungin (CAS), and micafungin (MFG) against planktonic cells and biofilms of bloodstream isolates of C. albicans (15 strains), Candida parapsilosis (6 strains), Candida lusitaniae (16 strains), Candida guilliermondii (5 strains), and Candida krusei (12 strains) by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] assay. Planktonic and biofilm MICs were defined as ≥50% fungal damage. Planktonic cells of all Candida species were susceptible to the three echinocandins, with MICs of ≤1 mg/liter. By comparison, differences in the MIC profiles of biofilms in response to echinocandins existed among the Candida species. Thus, C. lusitaniae and C. guilliermondii biofilms were highly recalcitrant to all echinocandins, with MICs of ≥32 mg/liter. In contrast, the MICs of all three echinocandins for C. albicans and C. krusei biofilms were relatively low (MICs ≤ 1 mg/liter). While echinocandins exhibited generally high MICs against C. parapsilosis biofilms, MFG exhibited the lowest MICs against these isolates (4 mg/liter). A paradoxical growth effect was observed with CAS concentrations ranging from 8 to 64 mg/liter against C. albicans and C. parapsilosis biofilms but not against C. krusei, C. lusitaniae, or C. guilliermondii. While non-albicans Candida planktonic cells were susceptible to all echinocandins, there were drug- and species-specific differences in susceptibility among biofilms of the various Candida species, with C. lusitaniae and C. guilliermondii exhibiting profiles of high MICs of the three echinocandins. PMID:23529739

Variation in Susceptibility to Wheat dwarf virus among Wild and Domesticated Wheat

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Nygren, Jim; Shad, Nadeem; Kvarnheden, Anders; Westerbergh, Anna

2015-01-01

We investigated the variation in plant response in host-pathogen interactions between wild (Aegilops spp., Triticum spp.) and domesticated wheat (Triticum spp.) and Wheat dwarf virus (WDV). The distribution of WDV and its wild host species overlaps in Western Asia in the Fertile Crescent, suggesting a coevolutionary relationship. Bread wheat originates from a natural hybridization between wild emmer wheat (carrying the A and B genomes) and the wild D genome donor Aegilops tauschii, followed by polyploidization and domestication. We studied whether the strong selection during these evolutionary processes, leading to genetic bottlenecks, may have resulted in a loss of resistance in domesticated wheat. In addition, we investigated whether putative fluctuations in intensity of selection imposed on the host-pathogen interactions have resulted in a variation in susceptibility to WDV. To test our hypotheses we evaluated eighteen wild and domesticated wheat taxa, directly or indirectly involved in wheat evolution, for traits associated with WDV disease such as leaf chlorosis, different growth traits and WDV content. The plants were exposed to viruliferous leafhoppers (Psammotettix alienus) in a greenhouse trial and evaluated at two time points. We found three different plant response patterns: i) continuous reduction in growth over time, ii) weak response at an early stage of plant development but a much stronger response at a later stage, and iii) remission of symptoms over time. Variation in susceptibility may be explained by differences in the intensity of natural selection, shaping the coevolutionary interaction between WDV and the wild relatives. However, genetic bottlenecks during wheat evolution have not had a strong impact on WDV resistance. Further, this study indicates that the variation in susceptibility may be associated with the genome type and that the ancestor Ae. tauschii may be useful as genetic resource for the improvement of WDV resistance in wheat. PMID

Variation in susceptibility to Wheat dwarf virus among wild and domesticated wheat.

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Jim Nygren

Full Text Available We investigated the variation in plant response in host-pathogen interactions between wild (Aegilops spp., Triticum spp. and domesticated wheat (Triticum spp. and Wheat dwarf virus (WDV. The distribution of WDV and its wild host species overlaps in Western Asia in the Fertile Crescent, suggesting a coevolutionary relationship. Bread wheat originates from a natural hybridization between wild emmer wheat (carrying the A and B genomes and the wild D genome donor Aegilops tauschii, followed by polyploidization and domestication. We studied whether the strong selection during these evolutionary processes, leading to genetic bottlenecks, may have resulted in a loss of resistance in domesticated wheat. In addition, we investigated whether putative fluctuations in intensity of selection imposed on the host-pathogen interactions have resulted in a variation in susceptibility to WDV. To test our hypotheses we evaluated eighteen wild and domesticated wheat taxa, directly or indirectly involved in wheat evolution, for traits associated with WDV disease such as leaf chlorosis, different growth traits and WDV content. The plants were exposed to viruliferous leafhoppers (Psammotettix alienus in a greenhouse trial and evaluated at two time points. We found three different plant response patterns: i continuous reduction in growth over time, ii weak response at an early stage of plant development but a much stronger response at a later stage, and iii remission of symptoms over time. Variation in susceptibility may be explained by differences in the intensity of natural selection, shaping the coevolutionary interaction between WDV and the wild relatives. However, genetic bottlenecks during wheat evolution have not had a strong impact on WDV resistance. Further, this study indicates that the variation in susceptibility may be associated with the genome type and that the ancestor Ae. tauschii may be useful as genetic resource for the improvement of WDV resistance in

Elevated Chitin Content Reduces the Susceptibility of Candida Species to Caspofungin

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Walker, Louise A.; Gow, Neil A. R.

2013-01-01

The echinocandin antifungal drugs inhibit synthesis of the major fungal cell wall polysaccharide β(1,3)-glucan. Echinocandins have good efficacy against Candida albicans but reduced activity against other Candida species, in particular Candida parapsilosis and Candida guilliermondii. Treatment of Candida albicans with a sub-MIC level of caspofungin has been reported to cause a compensatory increase in chitin content and to select for sporadic echinocandin-resistant FKS1 point mutants that also have elevated cell wall chitin. Here we show that elevated chitin in response to caspofungin is a common response in various Candida species. Activation of chitin synthesis was observed in isolates of C. albicans, Candida tropicalis, C. parapsilosis, and C. guilliermondii and in some isolates of Candida krusei in response to caspofungin treatment. However, Candida glabrata isolates demonstrated no exposure-induced change in chitin content. Furthermore, isolates of C. albicans, C. krusei, C. parapsilosis, and C. guilliermondii which were stimulated to have higher chitin levels via activation of the calcineurin and protein kinase C (PKC) signaling pathways had reduced susceptibility to caspofungin. Isolates containing point mutations in the FKS1 gene generally had higher chitin levels and did not demonstrate a further compensatory increase in chitin content in response to caspofungin treatment. These results highlight the potential of increased chitin synthesis as a potential mechanism of tolerance to caspofungin for the major pathogenic Candida species. PMID:23089748

Marek’s disease herpesvirus vaccines integrate into chicken host chromosomes yet lack a virus-host phenotype associated with oncogenic transformation

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Marek's disease (MD) is a lymphotrophic and oncogenic disease of chickens that can lead to death in susceptible and unimmunized host birds. The causative pathogen, Marek's disease virus (MDV), a highly oncogenic alphaherpesvirus, integrates into host genome near the telomeres during viral latency an...

Antifungal susceptibility testing of Candida species isolated from the immunocompromised patients admitted to ten university hospitals in Iran : comparison of colonizing and infecting isolates

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Badiee, Parisa; Badali, Hamid; Boekhout, Teun; Diba, Kambiz; Moghadam, Abdolkarim Ghadimi; Hossaini Nasab, Ali; Jafarian, Hadis; Mohammadi, Rasoul; Mirhendi, Hossein; Najafzadeh, Mohammad Javad; Shamsizadeh, Ahmad; Soltani, Jafar

2017-01-01

BACKGROUND: Antifungal susceptibility testing is a subject of interest in the field of medical mycology. The aim of the present study were the distributions and antifungal susceptibility patterns of various Candida species isolated from colonized and infected immunocompromised patients admitted to

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

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LeBoldus, Jared M; Isabel, Nathalie; Floate, Kevin D; Blenis, Peter; Thomas, Barb R

2013-01-01

Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis) and (or) to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or) hybridization ('phenological sink' hypothesis). We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined]) zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal pathogens in plant

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

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Jared M LeBoldus

Full Text Available Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis and (or to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or hybridization ('phenological sink' hypothesis. We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined] zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal

Synchrony of sylvatic dengue isolations: a multi-host, multi-vector SIR model of dengue virus transmission in Senegal.

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Benjamin M Althouse

Full Text Available Isolations of sylvatic dengue-2 virus from mosquitoes, humans and non-human primates in Senegal show synchronized multi-annual dynamics over the past 50 years. Host demography has been shown to directly affect the period between epidemics in other pathogen systems, therefore, one might expect unsynchronized multi-annual cycles occurring in hosts with dramatically different birth rates and life spans. However, in Senegal, we observe a single synchronized eight-year cycle across all vector species, suggesting synchronized dynamics in all vertebrate hosts. In the current study, we aim to explore two specific hypotheses: 1 primates with different demographics will experience outbreaks of dengue at different periodicities when observed as isolated systems, and that coupling of these subsystems through mosquito biting will act to synchronize incidence; and 2 the eight-year periodicity of isolations observed across multiple primate species is the result of long-term cycling in population immunity in the host populations. To test these hypotheses, we develop a multi-host, multi-vector Susceptible, Infected, Removed (SIR model to explore the effects of coupling multiple host-vector systems of dengue virus transmission through cross-species biting rates. We find that under small amounts of coupling, incidence in the host species synchronize. Long-period multi-annual dynamics are observed only when prevalence in troughs reaches vanishingly small levels (< 10(-10, suggesting that these dynamics are inconsistent with sustained transmission in this setting, but are consistent with local dengue virus extinctions followed by reintroductions. Inclusion of a constant introduction of infectious individuals into the system causes the multi-annual periods to shrink, while the effects of coupling remain the same. Inclusion of a stochastic rate of introduction allows for multi-annual periods at a cost of reduced synchrony. Thus, we conclude that the eight-year period

The double edge to parasite escape: invasive host is less infected but more infectable.

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Keogh, Carolyn L; Miura, Osamu; Nishimura, Tomohiro; Byers, James E

2017-09-01

Nonnative species that escape their native-range parasites may benefit not only from reduced infection pathology, but also from relaxed selection on costly immune defenses, promoting reallocation of resources toward growth or reproduction. However, benefits accruing from a reduction in defense could come at the cost of increased infection susceptibility. We conducted common garden studies of the shore crab Hemigrapsus sanguineus from highly parasitized native (Japan) populations and largely parasite-free invasive (USA) populations to test for differences in susceptibility to infection by native-range rhizocephalan parasites, and to explore differences in host resource allocation. Nonnative individuals showed at least 1.8 times greater susceptibility to infection than their native counterparts, and had reduced standing metabolic rates, suggesting that less of their energy was spent on physiological self-maintenance. Our results support an indirect advantage to parasite escape via the relaxation of costly physiological defenses. However, this advantage comes at the cost of heightened susceptibility, a trade-off of parasite escape that is seldom considered. © 2017 by the Ecological Society of America.

[A new parasitological index for the estimation of peculiarities of the relationships between parasite and its host, and biotope of the host].

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Bogdanov, I I; Chachina, S B; Korallo, N P; Dmitriev, V V

2006-01-01

A new parasitological index (hostal-topical index) for the estimation of the degree of ectoparasite's relationship with its host and biotope of the host is proposed: [formula: see text], where [formula: see text]--hostal-topical index; n--amount of ectoparasites of the given species on the given host species in the biotope; N--amount of ectoparasites of all species from the given taxonomic group on the given host species in the biotope; n1--amount of hosts of the given species in the biotope; N1--amount of hosts of all species from the given taxonomic group in the biotope; n2--amount of ectoparasites of the given species in the biotope; N2--amount of ectoparasites of all species from the given taxonomic group in the biotope. Values [formula: see text] 0.5 indicate a significant relationship with the host. By means of this index we have analyzed peculiarity of several parasitic species of fleas and gamasid mites to their hosts, biotopes, and biotope through the host. As it was found on the materials from different native zones and subzones of the Omsk Region (Western Siberia, Russia), values of the hostal-topical index for polyhostal parasitic species are lesser than those for oligohostal species. Values of this index can be different for the same species in the different native zones and subzones as well as in the different biotopes of the same native zone (subzone).

Antifungal susceptibility testing of Candida species isolated from the immunocompromised patients admitted to ten university hospitals in Iran: comparison of colonizing and infecting isolates

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Parisa Badiee

2017-11-01

Full Text Available Abstract Background Antifungal susceptibility testing is a subject of interest in the field of medical mycology. The aim of the present study were the distributions and antifungal susceptibility patterns of various Candida species isolated from colonized and infected immunocompromised patients admitted to ten university hospitals in Iran. Methods In totally, 846 Candida species were isolated from more than 4000 clinical samples and identified by the API 20 C AUX system. Antifungal susceptibility testing was performed by broth microdilution method according to CLSI. Results The most frequent Candida species isolated from all patients was Candida albicans (510/846. The epidemiological cutoff value and percentage of wild-type species for amphotericin B and fluconazole in Candida albicans, Candida tropicalis, Candida glabrata and Candida krusei were 0.5 μg/ml (95% and 4 μg/ml (96%; 1 μg/ml (95% and 8 μg/ml (95%; 0.5 μg/ml (99% and 19 μg/ml (98%; and 4 μg/ml (95% and 64 μg/ml (95%, respectively. The MIC90 and epidemiological cutoff values to posaconazole in Candida krusei were 0.5 μg/ml. There were significant differences between infecting and colonizing isolates of Candida tropicalis in MIC 90 values of amphotericin B, and isolates of Candida glabrata in values of amphotericin B, caspofungin, and voriconazole (P < 0.05. Conclusions Our findings suggest that the susceptibility patterns of Candida species (colonizing and infecting isolates in immunocompromised patients are not the same and acquired resistance was seen in some species.

The effect of diet and host genotype on ceca microbiota of Japanese quail fed a cholesterol enriched diet.

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Liu, Shasha; Bennett, Darin C; Tun, Hein M; Kim, Ji-Eun; Cheng, Kimberly M; Zhang, Hongfu; Leung, Frederick C

2015-01-01

Two Japanese quail strains, respectively atherosclerosis-susceptible (SUS) and -resistant (RES), have been shown to be good models to study cholesterol metabolism and transportation associated with atherosclerosis. Our objective was to examine possible difference in cecal microbiota between these strains when fed a control diet and a cholesterol enriched diet, to determine how host genotype and diet could affect the cecal microbiome that may play a part in cholesterol metabolism. A factorial study with both strains and two diets (control, cholesterol) was carried out. Cecal content was collected from 12 week old quail that have been on their respective diets for 6 weeks. DNA was extracted from the samples and the variable region 3-5 of the bacterial 16S rRNA gene was amplified. The amplicon libraries were subjected to pyrosequencing. Principal Component Analysis (PCA) of β-diversity showed four distinct microbiota communities that can be assigned to the 4 treatment groups (RES/control, RES/cholesterol, SUS/control, SUS/cholesterol). At the Phylum level, the 4 treatment groups has distinct Firmicutes community characteristics but no significant difference in Bacteroidetes. Eubacterium dolichum was rare in RES/control but became overabundant in RES/cholesterol. An unclassified species of Lactobacillaceae was found in abundance in SUS/control but the same species was rare in RES/cholesterol. On the other hand, two Lactobacillus species were only found in RES/control and an unclassified Lachnospiraceae species was abundant in RES/cholesterol but rare in SUS/control. The abundance of four species of Lachnospiraceae, three species of Ruminococcaceae and one species of Coprobacillaceae was positively correlated with plasma Total Cholesterol, plasma LDL, and LDL/HDL ratio. Our study of cecal microbiota in these quail has demonstrated that selection for susceptibility/resistance to diet induced atherosclerosis has also affected the quail's cecal environment to host

The effect of diet and host genotype on ceca microbiota of Japanese quail fed a cholesterol enriched diet

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Shasha eLiu

2015-10-01

Full Text Available Two Japanese quail strains, respectively atherosclerosis-susceptible (SUS and –resistant (RES, have been shown to be good models to study cholesterol metabolism and transportation associated with atherosclerosis. Our objective was to examine possible difference in cecal microbiota between these strains when fed a control diet and a cholesterol enriched diet, to determine how host genotype and diet could affect the cecal microbiome that may play a part in cholesterol metabolism. A factorial study with both strains and two diets (control, cholesterol was carried out. Cecal content was collected from 12 week old quail that have been on their respective diets for 6 weeks. DNA was extracted from the samples and the variable region 3 to 5 of the bacterial 16S rRNA gene was amplified. The amplicon libraries were subjected to pyrosequencing. Principal Component Analysis (PCA of β-diversity showed four distinct microbiota communities that can be assigned to the 4 treatment groups (RES/control, RES/cholesterol, SUS/control, SUS/cholesterol. At the Phylum level, the 4 treatment groups has distinct Firmicutes community characteristics but no significant difference in Bacteroidetes. Eubacterium dolichum was rare in RES/control but became overabundant in RES/cholesterol. An unclassified species of Lactobacillaceae was found in abundance in SUS/control but the same species was rare in RES/cholesterol. On the other hand, two Lactobacillus species were only found in RES/control and an unclassified Lachnospiraceae species was abundant in RES/cholesterol but rare in SUS/control. The abundance of 4 species of Lachnospiraceae, 3 species of Ruminococcaceae and one species of Coprobacillaceae was positively correlated with plasma Total Cholesterol, plasma LDL, and LDL/HDL ratio. Our study of cecal microbiota in these quail has demonstrated that selection for susceptibility/resistance to diet induced atherosclerosis has also affected the quail’s cecal environment

Climate forcing of an emerging pathogenic fungus across a montane multi-host community.

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Clare, Frances C; Halder, Julia B; Daniel, Olivia; Bielby, Jon; Semenov, Mikhail A; Jombart, Thibaut; Loyau, Adeline; Schmeller, Dirk S; Cunningham, Andrew A; Rowcliffe, Marcus; Garner, Trenton W J; Bosch, Jaime; Fisher, Matthew C

2016-12-05

Changes in the timings of seasonality as a result of anthropogenic climate change are predicted to occur over the coming decades. While this is expected to have widespread impacts on the dynamics of infectious disease through environmental forcing, empirical data are lacking. Here, we investigated whether seasonality, specifically the timing of spring ice-thaw, affected susceptibility to infection by the emerging pathogenic fungus Batrachochytrium dendrobatidis (Bd) across a montane community of amphibians that are suffering declines and extirpations as a consequence of this infection. We found a robust temporal association between the timing of the spring thaw and Bd infection in two host species, where we show that an early onset of spring forced high prevalences of infection. A third highly susceptible species (the midwife toad, Alytes obstetricans) maintained a high prevalence of infection independent of time of spring thaw. Our data show that perennially overwintering midwife toad larvae may act as a year-round reservoir of infection with variation in time of spring thaw determining the extent to which infection spills over into sympatric species. We used future temperature projections based on global climate models to demonstrate that the timing of spring thaw in this region will advance markedly by the 2050s, indicating that climate change will further force the severity of infection. Our findings on the effect of annual variability on multi-host infection dynamics show that the community-level impact of fungal infectious disease on biodiversity will need to be re-evaluated in the face of climate change.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Authors.

Replication and adaptive mutations of low pathogenic avian influenza viruses in tracheal organ cultures of different avian species.

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Henning Petersen

Full Text Available Transmission of avian influenza viruses (AIV between different avian species may require genome mutations that allow efficient virus replication in a new species and could increase virulence. To study the role of domestic poultry in the evolution of AIV we compared replication of low pathogenic (LP AIV of subtypes H9N2, H7N7 and H6N8 in tracheal organ cultures (TOC and primary embryo fibroblast cultures of chicken, turkey, Pekin duck and homing pigeon. Virus strain-dependent and avian species-related differences between LPAIV were observed in growth kinetics and induction of ciliostasis in TOC. In particular, our data demonstrate high susceptibility to LPAIV of turkey TOC contrasted with low susceptibility of homing pigeon TOC. Serial virus passages in the cells of heterologous host species resulted in adaptive mutations in the AIV genome, especially in the receptor-binding site and protease cleavage site of the hemagglutinin. Our data highlight differences in susceptibility of different birds to AIV viruses and emphasizes potential role of poultry in the emergence of new virus variants.

Mechanisms of Disease: Host-Pathogen Interactions between Burkholderia Species and Lung Epithelial Cells

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David, Jonathan; Bell, Rachel E.; Clark, Graeme C.

2015-01-01

Members of the Burkholderia species can cause a range of severe, often fatal, respiratory diseases. A variety of in vitro models of infection have been developed in an attempt to elucidate the mechanism by which Burkholderia spp. gain entry to and interact with the body. The majority of studies have tended to focus on the interaction of bacteria with phagocytic cells with a paucity of information available with regard to the lung epithelium. However, the lung epithelium is becoming more widely recognized as an important player in innate immunity and the early response to infections. Here we review the complex relationship between Burkholderia species and epithelial cells with an emphasis on the most pathogenic species, Burkholderia pseudomallei and Burkholderia mallei. The current gaps in knowledge in our understanding are highlighted along with the epithelial host-pathogen interactions that offer potential opportunities for therapeutic intervention. PMID:26636042

Unexpected effects of azole transporter inhibitors on antifungal susceptibility in Candida glabrata and other pathogenic Candida species.

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Nagayoshi, Yohsuke; Miyazaki, Taiga; Shimamura, Shintaro; Nakayama, Hironobu; Minematsu, Asuka; Yamauchi, Shunsuke; Takazono, Takahiro; Nakamura, Shigeki; Yanagihara, Katsunori; Kohno, Shigeru; Mukae, Hiroshi; Izumikawa, Koichi

2017-01-01

The pathogenic fungus Candida glabrata is often resistant to azole antifungal agents. Drug efflux through azole transporters, such as Cdr1 and Cdr2, is a key mechanism of azole resistance and these genes are under the control of the transcription factor Pdr1. Recently, the monoamine oxidase A (MAO-A) inhibitor clorgyline was shown to inhibit the azole efflux pumps, leading to increased azole susceptibility in C. glabrata. In the present study, we have evaluated the effects of clorgyline on susceptibility of C. glabrata to not only azoles, but also to micafungin and amphotericin B, using wild-type and several mutant strains. The addition of clorgyline to the culture media increased fluconazole susceptibility of a C. glabrata wild-type strain, whereas micafungin and amphotericin B susceptibilities were markedly decreased. These phenomena were also observed in other medically important Candida species, including Candida albicans, Candida parapsilosis, Candida tropicalis, and Candida krusei. Expression levels of CDR1, CDR2 and PDR1 mRNAs and an amount of Cdr1 protein in the C. glabrata wild-type strain were highly increased in response to the treatment with clorgyline. However, loss of Cdr1, Cdr2, Pdr1, and a putative clorgyline target (Fms1), which is an ortholog of human MAO-A, or overexpression of CDR1 did not affect the decreased susceptibility to micafungin and amphotericin B in the presence of clorgyline. The presence of other azole efflux pump inhibitors including milbemycin A4 oxime and carbonyl cyanide 3-chlorophenylhydrazone also decreased micafungin susceptibility in C. glabrata wild-type, Δcdr1, Δcdr2, and Δpdr1 strains. These findings suggest that azole efflux pump inhibitors increase azole susceptibility but concurrently induce decreased susceptibility to other classes of antifungals independent of azole transporter functions.

Transcriptome profiling during a natural host-parasite interaction.

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McTaggart, Seanna J; Cézard, Timothée; Garbutt, Jennie S; Wilson, Phil J; Little, Tom J

2015-08-28

Infection outcome in some coevolving host-pathogens is characterised by host-pathogen genetic interactions, where particular host genotypes are susceptible only to a subset of pathogen genotypes. To identify candidate genes responsible for the infection status of the host, we exposed a Daphnia magna host genotype to two bacterial strains of Pasteuria ramosa, one of which results in infection, while the other does not. At three time points (four, eight and 12 h) post pathogen exposure, we sequenced the complete transcriptome of the hosts using RNA-Seq (Illumina). We observed a rapid and transient response to pathogen treatment. Specifically, at the four-hour time point, eight genes were differentially expressed. At the eight-hour time point, a single gene was differentially expressed in the resistant combination only, and no genes were differentially expressed at the 12-h time point. We found that pathogen-associated transcriptional activity is greatest soon after exposure. Genome-wide resistant combinations were more likely to show upregulation of genes, while susceptible combinations were more likely to be downregulated, relative to controls. Our results also provide several novel candidate genes that may play a pivotal role in determining infection outcomes.

Are gall midge species (Diptera, Cecidomyiidae host-plant specialists? Espécies de moscas galhadoras (Diptera, Cecidomyiidae são especialistas em plantas hospedeiras?

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Marco Antonio A. Carneiro

2009-01-01

Full Text Available Despite the speciose fauna of gall-inducing insects in the Neotropical region, little is known about their taxonomy. On the other hand, gall morphotypes associated with host species have been extensively used as a surrogate of the inducer species worldwide. This study reviewed the described gall midges and their galls to test the generalization on the use of gall morphotypes as surrogates of gall midge species in the Brazilian fauna. We compiled taxonomic and biological data for 196 gall midge species recorded on 128 host plant species. Ninety two percent of those species were monophagous, inducing galls on a single host plant species, whereas only 5.6% species were oligophagous, inducing galls on more than one congeneric host plant species. Only four species induced galls on more than one host plant genus. We conclude that gall morphotypes associated with information on the host plant species and attacked organs are reliable surrogates of the gall-inducing species.Apesar do elevado número de espécies da fauna de insetos indutores de galhas na região Neotropical, muito pouco espécies foram descritas. Por outro lado, o morfotipo da galha associado com a espécie da planta hospedeira é em todo o mundo amplamente utilizado como um indicador da espécie de inseto indutor. Este estudo revê as espécies de cecidommídeos descritos e suas galhas para verificar a generalização do uso da morfologia da galha como indicador da espécie de cecidomíideo na fauna brasileira. Nós compilamos dados biológicos e taxonômicos de 196 espécies de cecidomiídeos em 128 espécies de plantas no Brasil. Noventa e dois porcento destas espécies foram monófagas, induzindo galhas em uma única espécie de planta hospedeira, enquanto somente 5,6% das espécies foram oligófagas, induzindo galhas em mais de uma espécie de planta do mesmo gênero. Somente quatro espécies induzem galhas em espécies de plantas de gêneros diferentes. Nós concluímos que o morfo

Candida species distribution and fluconazole susceptibility of blood isolates at a regional hospital in Passo Fundo, RS, Brazil

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Maira Giseli C. Silva

2015-06-01

Full Text Available ABSTRACT Introduction: Candidemia is a bloodstream infection produced by Candida genus yeasts. Objective: The purpose of this study was to characterize the epidemiology and the fluconazole susceptibility in Candida species isolated from patients at a regional hospital in Passo Fundo, RS. Methods: Records from the laboratory were used to identify patients with positive blood cultures for Candida between 2010 and 2011. The in vitro activity of fluconazole was determined using the disk diffusion method. Results: Were analyzed 24 positive blood cultures for Candida and found a 54.16% mortality rate. C. albicans was the most prevalent species, followed by C. parapsilosis and C. krusei. For susceptibility to fluconazole, C. albicans, C. parapsilosis and C. tropicalis showed 100% sensitivity. However, C. krusei was 100% resistant; and C. glabrata, 50% resistant. Conclusion: The high mortality and fluconazole resistance rates emphasize the importance of the diagnosis of candidemia in a hospital environment.

Alloxenic distribution of cystacanths of two Profilicollis species in sympatric crustacean hosts in Chile.

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Balboa, L; Hinojosa, A; Riquelme, C; Rodríguez, S; Bustos, J; George-Nascimento, M

2009-10-01

The taxonomic status of Profilicollis ( = Falsifilicollis Webster, 1948) species in crustaceans in Chile is examined. Mole crabs, Emerita analoga (Stimpson 1857), living in the splash zone of a sandy beach at Lenga off the coast of central Chile, harbor Polymorphus (Profilicollis) bullocki Mateo, Córdova and Guzmán 1982, while the estuarine crabs, Hemigrapsus crenulatus (Milne-Edwards, 1837), living in an oligohaline inlet at the same site, harbor Profilicollis spp. cystacanths which cannot be distinguished specifically to either Profilicollis antarcticus or P. chasmagnathi Holcman-Spector, Mañé-Garzón and Dei-Cas 1977. We found no morphological data supporting records of P. altmani along the coast of Chile. Therefore, and after examination of both their morphology and the literature, we consider that P. bullocki must be reinstated as a valid species in the genus. There is a widespread distribution of habitats, such as sandy beaches and inlets, as well as a variety of host taxa involved in the life cycle of Profilicollis spp. Consequently, they provide an interesting scenario for testing hypotheses regarding the coevolution and host specificity of these parasites.

Hybridism between Biomphalaria cousini and Biomphalaria amazonica and its susceptibility to Schistosoma mansoni

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Tatiana Maria Teodoro

2011-11-01

Full Text Available Molecular techniques can aid in the classification of Biomphalaria species because morphological differentiation between these species is difficult. Previous studies using phylogeny, morphological and molecular taxonomy showed that some populations studied were Biomphalaria cousini instead of Biomphalaria amazonica. Three different molecular profiles were observed that enabled the separation of B. amazonica from B. cousini. The third profile showed an association between the two and suggested the possibility of hybrids between them. Therefore, the aim of this work was to investigate the hybridism between B. cousini and B. amazonica and to verify if the hybrids are susceptible to Schistosoma mansoni. Crosses using the albinism factor as a genetic marker were performed, with pigmented B. cousini and albino B. amazonica snails identified by polymerase chain reaction-restriction fragment length polymorphism. This procedure was conducted using B. cousini and B. amazonica of the type locality accordingly to Paraense, 1966. In addition, susceptibility studies were performed using snails obtained from the crosses (hybrids and three S. mansoni strains (LE, SJ, AL. The crosses between B. amazonica and B. cousini confirmed the occurrence of hybrids. Moreover, hybrids can be considered potential hosts of S. mansoni because they are susceptible to LE, SJ and AL strains (4.4%, 5.6% and 2.2%, respectively. These results indicate that there is a risk of introducing schistosomiasis mansoni into new areas.

Secondary metabolite profiles and antifungal drug susceptibility of Aspergillus fumigatus and closely related species, Aspergillus lentulus, Aspergillus udagawae, and Aspergillus viridinutans.

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Tamiya, Hiroyuki; Ochiai, Eri; Kikuchi, Kazuyo; Yahiro, Maki; Toyotome, Takahito; Watanabe, Akira; Yaguchi, Takashi; Kamei, Katsuhiko

2015-05-01

The incidence of Aspergillus infection has been increasing in the past few years. Also, new Aspergillus fumigatus-related species, namely Aspergillus lentulus, Aspergillus udagawae, and Aspergillus viridinutans, were shown to infect humans. These fungi exhibit marked morphological similarities to A. fumigatus, albeit with different clinical courses and antifungal drug susceptibilities. The present study used liquid chromatography/time-of-flight mass spectrometry to identify the secondary metabolites secreted as virulence factors by these Aspergillus species and compared their antifungal susceptibility. The metabolite profiles varied widely among A. fumigatus, A. lentulus, A. udagawae, and A. viridinutans, producing 27, 13, 8, and 11 substances, respectively. Among the mycotoxins, fumifungin, fumiquinazoline A/B and D, fumitremorgin B, gliotoxin, sphingofungins, pseurotins, and verruculogen were only found in A. fumigatus, whereas auranthine was only found in A. lentulus. The amount of gliotoxin, one of the most abundant mycotoxins in A. fumigatus, was negligible in these related species. In addition, they had decreased susceptibility to antifungal agents such as itraconazole and voriconazole, even though metabolites that were shared in the isolates showing higher minimum inhibitory concentrations than epidemiological cutoff values were not detected. These strikingly different secondary metabolite profiles may lead to the development of more discriminative identification protocols for such closely related Aspergillus species as well as improved treatment outcomes. Copyright © 2015 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

A novel Capsicum gene inhibits host-specific disease resistance to Phytophthora capsici.

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Reeves, Gregory; Monroy-Barbosa, Ariadna; Bosland, Paul W

2013-05-01

A novel disease resistance inhibitor gene (inhibitor of P. capsici resistance [Ipcr]), found in the chile pepper (Capsicum annuum) variety 'New Mexico Capsicum Accession 10399' (NMCA10399), inhibits resistance to Phytophthora capsici but not to other species of Phytophthora. When a highly P. capsici-resistant variety was hybridized with NMCA10399, the resultant F1 populations, when screened, were completely susceptible to P. capsici for root rot and foliar blight disease syndromes, despite the dominance inheritance of P. capsici resistance in chile pepper. The F2 population displayed a 3:13 resistant-to-susceptible (R:S) ratio. The testcross population displayed a 1:1 R:S ratio, and a backcross population to NMCA10399 displayed complete susceptibility. These results demonstrate the presence of a single dominant inhibitor gene affecting P. capsici resistance in chile pepper. Moreover, when lines carrying the Ipcr gene were challenged against six Phytophthora spp., the nonhost resistance was not overcome. Therefore, the Ipcr gene is interfering with host-specific resistance but not the pathogen- or microbe-associated molecular pattern nonhost responses.

Analysis of virus susceptibility in the invasive insect pest Drosophila suzukii.

Science.gov (United States)

Lee, Kwang-Zin; Vilcinskas, Andreas

2017-09-01

The invasive insect pest Drosophila suzukii infests ripening fruits and causes massive agricultural damage in North America and Europe (Cini et al., 2012). Environmentally sustainable strategies are urgently needed to control the spread of this species, and entomopathogenic viruses offer one potential solution for global crop protection. Here we report the status of intrinsic and extrinsic factors that influence the susceptibility of D. suzukii to three model insect viruses: Drosophila C virus, Cricket paralysis virus and Flock house virus. Our work provides the basis for further studies using D. suzukii as a host system to develop viruses as biological control agents. Copyright © 2017 Elsevier Inc. All rights reserved.

Oral vaccination of wildlife against rabies: Differences among host species in vaccine uptake efficiency.

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Vos, Ad; Freuling, Conrad M; Hundt, Boris; Kaiser, Christiane; Nemitz, Sabine; Neubert, Andreas; Nolden, Tobias; Teifke, Jens P; Te Kamp, Verena; Ulrich, Reiner; Finke, Stefan; Müller, Thomas

2017-07-13

Oral vaccination using attenuated and recombinant rabies vaccines has been proven a powerful tool to combat rabies in wildlife. However, clear differences have been observed in vaccine titers needed to induce a protective immune response against rabies after oral vaccination in different reservoir species. The mechanisms contributing to the observed resistance against oral rabies vaccination in some species are not completely understood. Hence, the immunogenicity of the vaccine virus strain, SPBN GASGAS, was investigated in a species considered to be susceptible to oral rabies vaccination (red fox) and a species refractory to this route of administration (striped skunk). Additionally, the dissemination of the vaccine virus in the oral cavity was analyzed for these two species. It was shown that the palatine tonsils play a critical role in vaccine virus uptake. Main differences could be observed in palatine tonsil infection between both species, revealing a locally restricted dissemination of infected cells in foxes. The absence of virus infected cells in palatine tonsils of skunks suggests a less efficient uptake of or infection by vaccine virus which may lead to a reduced response to oral vaccination. Understanding the mechanisms of oral resistance to rabies virus vaccine absorption and primary replication may lead to the development of novel strategies to enhance vaccine efficacy in problematic species like the striped skunk. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Genome-wide association studies on HIV susceptibility, pathogenesis and pharmacogenomics

NARCIS (Netherlands)

van Manen, Daniëlle; van 't Wout, Angélique B.; Schuitemaker, Hanneke

2012-01-01

Susceptibility to HIV-1 and the clinical course after infection show a substantial heterogeneity between individuals. Part of this variability can be attributed to host genetic variation. Initial candidate gene studies have revealed interesting host factors that influence HIV infection, replication

Identification of drug susceptibility pattern and mycobacterial species in sputum smear positive pulmonary tuberculosis patients with and without HIV co-infection in north west Ethiopia

DEFF Research Database (Denmark)

Mekonen, Mekdem; Abate, Ebba; Aseffa, Abraham

2010-01-01

Ethiopia is among the high-burden countries of tuberculosis (TB) in the world Since mycobacterial culture and susceptibility testing are not routinely performed in Ethiopia, recent data on susceptibility patterns and the mycobacterial species cultured from sputum smear positive patients are limited....

Animal salmonelloses: a brief review of “host adaptation and host specificity” of Salmonella spp.

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Grammato Evangelopoulou

2013-07-01

Full Text Available Salmonella enterica, the most pathogenic species of the genusSalmonella, includes more than 2,500 serovars, many of which are of great veterinary and medical significance. The emergence of food-borne pathogens, such as Salmonella spp., has increased knowledge about the mechanisms helping microorganisms to persist and spread within new host populations. It has also increased information about the properties they acquire for adapting in the biological environment of a new host. Thedifferences observed between serovars in their host preference and clinical manifestations are referred to as “serovar-host specificity” or “serovar-host adaptation”. The genus Salmonella, highly adaptive to vertebrate hosts, has many pathogenic serovars showing host specificity. Serovar Salmonella Typhi, causing disease to man and higher primates, is a good example of host specificity. Thus, understanding the mechanisms that Salmonella serovars use to overcome animal species' barriers or adapt to new hosts is also important for understanding the origins of any other infectious diseases or the emergence of new pathogens. In addition, molecular methods used to study the virulence determinants of Salmonella serovars, could also be used to model ways of studying the virulence determinants used by bacteria in general, when causing disease to a specific animal species

IRES-mediated translation of foot-and-mouth disease virus (FMDV) in cultured cells derived from FMDV-susceptible and -insusceptible animals.

Science.gov (United States)

Kanda, Takehiro; Ozawa, Makoto; Tsukiyama-Kohara, Kyoko

2016-03-31

Foot-and-mouth disease virus (FMDV) possess a positive sense, single stranded RNA genome. Internal ribosomal entry site (IRES) element exists within its 5' untranslated region (5'UTR) of the viral RNA. Translation of the viral RNA is initiated by internal entry of the 40S ribosome within the IRES element. This process is facilitated by cellular factors known as IRES trans-acting factors (ITAFs). Foot-and-mouth disease (FMD) is host-restricted disease for cloven-hoofed animals such as cattle and pigs, but the factors determining the host range have not been identified yet. Although, ITAFs are known to promote IRES-mediated translation, these findings were confirmed only in cells derived from FMDV-insusceptible animals so far. We evaluated and compared the IRES-mediated translation activities among cell lines derived from four different animal species using bicistronic luciferase reporter plasmid, which possesses an FMDV-IRES element between Renilla and Firefly luciferase genes. Furthermore, we analyzed the effect of the cellular factors on IRES-mediated translation by silencing the cellular factors using siRNA in both FMDV-susceptible and -insusceptible animal cells. Our data indicated that IRES-mediated translational activity was not linked to FMDV host range. ITAF45 promoted IRES-mediated translation in all cell lines, and the effects of poly-pyrimidine tract binding protein (PTB) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) were observed only in FMDV-susceptible cells. Thus, PTB and 4E-BP1 may influence the host range of FMDV. IRES-mediated translation activity of FMDV was not predictive of its host range. ITAF45 promoted IRES-mediated translation in all cells, and the effects of PTB and 4E-BP1 were observed only in FMDV-susceptible cells.

Yeasts from Scarlet ibises (Eudocimus ruber): A focus on monitoring the antifungal susceptibility of Candida famata and closely related species.

Science.gov (United States)

Brilhante, Raimunda Sâmia Nogueira; Silva, Aline Lobão da; Monteiro, Frederico Ozanan Barros; Guedes, Glaucia Morgana de Melo; Sales, Jamille Alencar; Oliveira, Jonathas Sales de; Maia Junior, José Erisvaldo; Miranda, Stefânia Araújo; Sidrim, José Júlio Costa; Alencar, Lucas Pereira de; Castelo-Branco, Débora Souza Collares Maia; Cordeiro, Rossana de Aguiar; Pereira Neto, Waldemiro de Aquino; Rocha, Marcos Fábio Gadelha

2017-10-01

This study aimed to identify yeasts from the gastrointestinal tract of scarlet ibises (Eudocimus ruber) and from plant material collected from the environment where they live. Then, the isolates phenotypically identified as Candida famata were submitted to molecular identification of their closely related species and evaluated for their antifungal susceptibility and possible resistance mechanisms to antifungal drugs. Cloacal swabs from 20 scarlet ibises kept in captivity at Mangal das Garças Park (Brazil), pooled stool samples (n = 20) and samples of trunks and hollow of trees (n = 20) obtained from their enclosures were collected. The samples were seeded on Sabouraud agar supplemented with chloramphenicol. The 48 recovered isolates were phenotypically identified as 15 Candida famata, 13 Candida catenulata, 2 Candida intermedia, 1 Candida lusitaniae, 2 Candida guilliermondii, 1 Candida kefyr, 1 Candida amapae, 1 Candida krusei, 8 Trichosporon spp., and 4 Rhodotorula spp. The C. famata isolates were further identified as 3 C. famata, 8 Debaryomyces nepalensis, and 4 C. palmioleophila. All C. famata and C. palmioleophila were susceptible to caspofungin and itraconazole, while one D. nepalensis was resistant to fluconazole and voriconazole. This same isolate and another D. nepalensis had lower amphotericin B susceptibility. The azole resistant strain had an increased efflux of rhodamine 6G and an alteration in the membrane sterol content, demonstrating multifactorial resistance mechanism. Finally, this research shows that scarlet ibises and their environment harbor C. famata and closely related species, including antifungal resistant isolates, emphasizing the need of monitoring the antifungal susceptibility of these yeast species. © The Author 2017. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Migratory status is not related to the susceptibility to HPAIV H5N1 in an insectivorous passerine species.

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Donata Kalthoff

Full Text Available Migratory birds have evolved elaborate physiological adaptations to travelling, the implications for their susceptibility to avian influenza are however unknown. Three groups of stonechats (Saxicola torquata from (I strongly migrating, (II weakly migrating and (III non-migrating populations were experimentally infected with HPAIV H5N1. The different bird groups of this insectivorous passerine species were infected in autumn, when the migrating populations clearly exhibit migratory restlessness. Following infection, all animals succumbed to the disease from 3 through 7 days post inoculation. Viral shedding, antigen distribution in tissues, and survival time did not differ between the three populations. However, notably, endothelial tropism of the HPAIV infection was exclusively seen in the group of resident birds. In conclusion, our data document for the first time the high susceptibility of an insectivorous passerine species to H5N1 infection, and the epidemiological role of these passerine birds is probably limited due to their high sensitivity to HPAIV H5N1 infection. Despite pronounced inherited differences in migratory status, the groups were generally indistinguishable in their susceptibility, survival time, clinical symptoms and viral shedding. Nevertheless, the migratory status partly influenced pathogenesis in the way of viral tropism.

Differential precocious sexual development of Proctoeces lintoni (Digenea: Fellodistomidae) in three sympatric species of keyhole limpets Fissurella spp. may affect transmission to the final host.

Science.gov (United States)

Balboa, L; George-Nascimento, M; Ojeda, F P

2001-10-01

The prevalence, abundance, and developmental status of the digenetic trematode Proctoeces lintoni Siddiqui et Cable 1960 were compared in 3 species of keyhole limpets Fissurella. A total of 197 limpets was collected at Caleta Chome, south-central Chile. Fissurella picta and F. costata had the highest prevalence of infection, whereas F. picta showed the greatest abundance of parasites, which increased with host shell length. However, the frequency of P. lintoni specimens with eggs in the uterus was greatest in F. costata. These results suggest that an increased rate of development of a parasite in the intermediate host may shorten the residence time necessary for maturation in the final host. Thus, faster development of the parasite in F. costata suggests the possibility that the parasites transmitted through this host species have shorter maturation times in clingfishes than individuals transmitted via other limpet species.

Transcriptome analysis of root-knot nematode (Meloidogyne incognita)-infected tomato (Solanum lycopersicum) roots reveals complex gene expression profiles and metabolic networks of both host and nematode during susceptible and resistance responses

DEFF Research Database (Denmark)

Shukla, Neha; Yadav, Rachita; Kaur, Pritam

2017-01-01

Root knot nematodes (RKNs, Meloidogyne incognita) are economically important endoparasites having a wide-host range. We have taken a comprehensive transcriptomic approach to investigate the expression of both tomato and RKN genes in tomato roots at five infection time intervals from susceptible p...

Transcriptome analysis of root-knot nematode (Meloidogyne incognita)-infected tomato (Solanum lycopersicum) roots reveals complex gene expression profiles and metabolic networks of both host and nematode during susceptible and resistance responses

DEFF Research Database (Denmark)

Shukla, Neha; Yadav, Rachita; Kaur, Pritam

2018-01-01

Root knot nematodes (RKNs, Meloidogyne incognita) are economically important endoparasites having a wide-host range. We have taken a comprehensive transcriptomic approach to investigate the expression of both tomato and RKN genes in tomato roots at five infection time intervals from susceptible p...

New species of Cryptosporidium Tyzzer, 1907 (Apicomplexa) from amphibian host: morphology, biology and phylogeny

Czech Academy of Sciences Publication Activity Database

Jirků, Miloslav; Valigurová, A.; Koudela, Břetislav; Křížek, Jaroslav; Modrý, David; Šlapeta, J.

2008-01-01

Roč. 55, č. 2 (2008), s. 81-94 ISSN 0015-5683 R&D Projects: GA ČR GD524/03/H133; GA ČR GA524/05/0992; GA MŠk LC522 Institutional research plan: CEZ:AV0Z60220518 Keywords : Cryptosporidium fragile * new species * Duttaphrynus melanostictus * Host specificity * ultrastructure * global amphibian decline * hylogeny * quarantine Subject RIV: EG - Zoology Impact factor: 1.307, year: 2008

Host species and environmental effects on bacterial communities associated with Drosophila in the laboratory and in the natural environment.

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Fabian Staubach

Full Text Available The fruit fly Drosophila is a classic model organism to study adaptation as well as the relationship between genetic variation and phenotypes. Although associated bacterial communities might be important for many aspects of Drosophila biology, knowledge about their diversity, composition, and factors shaping them is limited. We used 454-based sequencing of a variable region of the bacterial 16S ribosomal RNA gene to characterize the bacterial communities associated with wild and laboratory Drosophila isolates. In order to specifically investigate effects of food source and host species on bacterial communities, we analyzed samples from wild Drosophila melanogaster and D. simulans collected from a variety of natural substrates, as well as from adults and larvae of nine laboratory-reared Drosophila species. We find no evidence for host species effects in lab-reared flies; instead, lab of origin and stochastic effects, which could influence studies of Drosophila phenotypes, are pronounced. In contrast, the natural Drosophila-associated microbiota appears to be predominantly shaped by food substrate with an additional but smaller effect of host species identity. We identify a core member of this natural microbiota that belongs to the genus Gluconobacter and is common to all wild-caught flies in this study, but absent from the laboratory. This makes it a strong candidate for being part of what could be a natural D. melanogaster and D. simulans core microbiome. Furthermore, we were able to identify candidate pathogens in natural fly isolates.

Unrecognized coral species diversity masks differences in functional ecology.

Science.gov (United States)

Boulay, Jennifer N; Hellberg, Michael E; Cortés, Jorge; Baums, Iliana B

2014-02-07

Porites corals are foundation species on Pacific reefs but a confused taxonomy hinders understanding of their ecosystem function and responses to climate change. Here, we show that what has been considered a single species in the eastern tropical Pacific, Porites lobata, includes a morphologically similar yet ecologically distinct species, Porites evermanni. While P. lobata reproduces mainly sexually, P. evermanni dominates in areas where triggerfish prey on bioeroding mussels living within the coral skeleton, thereby generating asexual coral fragments. These fragments proliferate in marginal habitat not colonized by P. lobata. The two Porites species also show a differential bleaching response despite hosting the same dominant symbiont subclade. Thus, hidden diversity within these reef-builders has until now obscured differences in trophic interactions, reproductive dynamics and bleaching susceptibility, indicative of differential responses when confronted with future climate change.

The abundance and host-seeking behavior of culicine species (Diptera: Culicidae and Anopheles sinensis in Yongcheng city, people's Republic of China

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Liu Xiao-Bo

2011-11-01

Full Text Available Abstract Background The knowledge of mosquito species diversity and the level of anthropophily exhibited by each species in a region are of great importance to the integrated vector control. Culicine species are the primary vectors of Japanese encephalitis (JE virus and filariasis in China. Anopheles sinensis plays a major role in the maintenance of Plasmodium vivax malaria transmission in China. The goal of this study was to compare the abundance and host-seeking behavior of culicine species and An. sinensis in Yongcheng city, a representative region of P. vivax malaria. Specifically, we wished to determine the relative attractiveness of different animal baits versus human bait to culicine species and An. sinensis. Results Culex tritaeniorhynchus was the most prevalent mosquito species and An. sinensis was the sole potential vector of P. vivax malaria in Yongcheng city. There were significant differences (P An. sinensis and Cx. tritaeniorhynchus collected in distinct baited traps. The relative attractiveness of animal versus human bait was similar towards both An. sinensis and Cx. tritaeniorhynchus. The ranking derived from the mean number of mosquitoes per bait indicated that pigs, goats and calves frequently attracted more mosquitoes than the other hosts tested (dogs, humans, and chickens. These trends were similar across all capture nights at three distinct villages. The human blood index (HBI of female An. sinensis was 2.94% when computed with mixed meals while 3.70% computed with only the single meal. 19:00~21:00 was the primary peak of host-seeking female An. sinensis while 4:00~5:00 was the smaller peak at night. There was significant correlation between the density of female An. sinensis and the average relative humidity (P Conclusions Pigs, goats and calves were more attractive to An. sinensis and Cx. tritaeniorhynchus than dogs, humans, and chickens. Female An. sinensis host-seeking activity mainly occurred from 19:00 to 21:00. Thus

Topological congruence between phylogenies of Anacanthorus spp. (Monogenea: Dactylogyridae) and their Characiformes (Actinopterygii) hosts: A case of host-parasite cospeciation.

Science.gov (United States)

da Graça, Rodrigo J; Fabrin, Thomaz M C; Gasques, Luciano S; Prioli, Sônia M A P; Balbuena, Juan A; Prioli, Alberto J; Takemoto, Ricardo M

2018-01-01

Cophylogenetic studies aim at testing specific hypotheses to understand the nature of coevolving associations between sets of organisms, such as host and parasites. Monogeneans and their hosts provide and interesting platform for these studies due to their high host specificity. In this context, the objective of the present study was to establish whether the relationship between Anacanthorus spp. with their hosts from the upper Paraná River and its tributaries can be explained by means of cospeciation processes. Nine fish species and 14 monogenean species, most of them host specific, were studied. Partial DNA sequences of the genes RAG1, 16S and COI of the fish hosts and of the genes ITS2, COI and 5.8S of the parasite species were used for phylogenetic reconstruction. Maximum likelihood phylogenetic trees of the host and parasite species were built and used for analyses of topological congruence with PACo and ParaFit. The program Jane was used to estimate the nature of cospeciation events. The comparison of the two phylogenies revealed high topological congruence between them. Both PACo and ParaFit supported the hypothesis of global cospeciation. Results from Jane pointed to duplications as the most frequent coevolutionary event, followed by cospeciation, whereas duplications followed by host-switching were the least common event in Anacanthorus spp. studied. Host-sharing (spreading) was also identified but only between congeneric host species.

Phylogeny of the Clinically Relevant Species of the Emerging Fungus Trichoderma and Their Antifungal Susceptibilities

Science.gov (United States)

Sandoval-Denis, Marcelo; Sutton, Deanna A.; Cano-Lira, José F.; Fothergill, Annette W.; Wiederhold, Nathan P.; Guarro, Josep

2014-01-01

A set of 73 isolates of the emerging fungus Trichoderma isolated from human and animal clinical specimens were characterized morphologically and molecularly using a multilocus sequence analysis that included the internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA and fragments of the translation elongation factor 1 alpha (Tef1), endochitinase CHI18-5 (Chi18-5), and actin 1 (Act1) genes. The most frequent species was Trichoderma longibrachiatum (26%), followed by Trichoderma citrinoviride (18%), the Hypocrea lixii/Trichoderma harzianum species complex (15%), the newly described species Trichoderma bissettii (12%), and Trichoderma orientale (11%). The most common anatomical sites of isolation in human clinical specimens were the respiratory tract (40%), followed by deep tissue (30%) and superficial tissues (26%), while all the animal-associated isolates were obtained from superficial tissue samples. Susceptibilities of the isolates to eight antifungal drugs in vitro showed mostly high MICs, except for voriconazole and the echinocandins. PMID:24719448

Large-Scale Removal of Invasive Honeysuckle Decreases Mosquito and Avian Host Abundance.

Science.gov (United States)

Gardner, Allison M; Muturi, Ephantus J; Overmier, Leah D; Allan, Brian F

2017-12-01

Invasive species rank second only to habitat destruction as a threat to native biodiversity. One consequence of biological invasions is altered risk of exposure to infectious diseases in human and animal populations. The distribution and prevalence of mosquito-borne diseases depend on the complex interactions between the vector, the pathogen, and the human or wildlife reservoir host. These interactions are highly susceptible to disturbance by invasive species, including terrestrial plants. We conducted a 2-year field experiment using a Before-After/Control-Impact design to examine how removal of invasive Amur honeysuckle (Lonicera maackii) in a forest fragment embedded within a residential neighborhood affects the abundance of mosquitoes, including two of the most important vectors of West Nile virus, Culex pipiens and Cx. restuans. We also assessed any potential changes in avian communities and local microclimate associated with Amur honeysuckle removal. We found that (1) removal of Amur honeysuckle reduces the abundance of both vector and non-vector mosquito species that commonly feed on human hosts, (2) the abundance and composition of avian hosts is altered by honeysuckle removal, and (3) areas invaded with honeysuckle support local microclimates that are favorable to mosquito survival. Collectively, our investigations demonstrate the role of a highly invasive understory shrub in determining the abundance and distribution of mosquitoes and suggest potential mechanisms underlying this pattern. Our results also give rise to additional questions regarding the general impact of invasive plants on vector-borne diseases and the spatial scale at which removal of invasive plants may be utilized to effect disease control.

Humanized TLR4/MD-2 mice reveal LPS recognition differentially impacts susceptibility to Yersinia pestis and Salmonella enterica.

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Adeline M Hajjar

Full Text Available Although lipopolysaccharide (LPS stimulation through the Toll-like receptor (TLR-4/MD-2 receptor complex activates host defense against Gram-negative bacterial pathogens, how species-specific differences in LPS recognition impact host defense remains undefined. Herein, we establish how temperature dependent shifts in the lipid A of Yersinia pestis LPS that differentially impact recognition by mouse versus human TLR4/MD-2 dictate infection susceptibility. When grown at 37°C, Y. pestis LPS is hypo-acylated and less stimulatory to human compared with murine TLR4/MD-2. By contrast, when grown at reduced temperatures, Y. pestis LPS is more acylated, and stimulates cells equally via human and mouse TLR4/MD-2. To investigate how these temperature dependent shifts in LPS impact infection susceptibility, transgenic mice expressing human rather than mouse TLR4/MD-2 were generated. We found the increased susceptibility to Y. pestis for "humanized" TLR4/MD-2 mice directly paralleled blunted inflammatory cytokine production in response to stimulation with purified LPS. By contrast, for other Gram-negative pathogens with highly acylated lipid A including Salmonella enterica or Escherichia coli, infection susceptibility and the response after stimulation with LPS were indistinguishable between mice expressing human or mouse TLR4/MD-2. Thus, Y. pestis exploits temperature-dependent shifts in LPS acylation to selectively evade recognition by human TLR4/MD-2 uncovered with "humanized" TLR4/MD-2 transgenic mice.

Humanized TLR4/MD-2 mice reveal LPS recognition differentially impacts susceptibility to Yersinia pestis and Salmonella enterica.

Science.gov (United States)

Hajjar, Adeline M; Ernst, Robert K; Fortuno, Edgardo S; Brasfield, Alicia S; Yam, Cathy S; Newlon, Lindsay A; Kollmann, Tobias R; Miller, Samuel I; Wilson, Christopher B

2012-01-01

Although lipopolysaccharide (LPS) stimulation through the Toll-like receptor (TLR)-4/MD-2 receptor complex activates host defense against Gram-negative bacterial pathogens, how species-specific differences in LPS recognition impact host defense remains undefined. Herein, we establish how temperature dependent shifts in the lipid A of Yersinia pestis LPS that differentially impact recognition by mouse versus human TLR4/MD-2 dictate infection susceptibility. When grown at 37°C, Y. pestis LPS is hypo-acylated and less stimulatory to human compared with murine TLR4/MD-2. By contrast, when grown at reduced temperatures, Y. pestis LPS is more acylated, and stimulates cells equally via human and mouse TLR4/MD-2. To investigate how these temperature dependent shifts in LPS impact infection susceptibility, transgenic mice expressing human rather than mouse TLR4/MD-2 were generated. We found the increased susceptibility to Y. pestis for "humanized" TLR4/MD-2 mice directly paralleled blunted inflammatory cytokine production in response to stimulation with purified LPS. By contrast, for other Gram-negative pathogens with highly acylated lipid A including Salmonella enterica or Escherichia coli, infection susceptibility and the response after stimulation with LPS were indistinguishable between mice expressing human or mouse TLR4/MD-2. Thus, Y. pestis exploits temperature-dependent shifts in LPS acylation to selectively evade recognition by human TLR4/MD-2 uncovered with "humanized" TLR4/MD-2 transgenic mice.

Toxocariasis in Carnivora from Argentinean Patagonia: Species molecular identification, hosts, and geographical distribution

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R.M. Vega

2018-04-01

Full Text Available Twenty four specimens of seven species belonging to the families Felidae, Mustelidae, and Canidae were obtained in Lanín and Nahuel Huapi National Parks from March 1996 to April 2016. Specimens were processed by necropsy in order to contribute to the knowledge of toxocariasis in wild carnivores of Argentinean Patagonia. The only Puma concolor and the seven Leopardus geoffroyi were positive for Toxocara cati. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP of the ITS-1 region from larval and adult DNA was carried out to confirm parasite species identification. This is the first molecular determination of T. cati from wild felids in Argentina and the study also fill gaps about the spatial distribution and hosts for Toxocara cati. Keywords: Toxocara cati, Puma concolor, Leopardus geoffroyi, Molecular identification, Argentina

Susceptibility profiles of Nocardia isolates based on current taxonomy.

Science.gov (United States)

Schlaberg, Robert; Fisher, Mark A; Hanson, Kimberley E

2014-01-01

The genus Nocardia has undergone rapid taxonomic expansion in recent years, and an increasing number of species are recognized as human pathogens. Many established species have predictable antimicrobial susceptibility profiles, but sufficient information is often not available for recently described organisms. Additionally, the effectiveness of sulfonamides as first-line drugs for Nocardia has recently been questioned. This led us to review antimicrobial susceptibility patterns for a large number of molecularly identified clinical isolates. Susceptibility results were available for 1,299 isolates representing 39 different species or complexes, including 11 that were newly described, during a 6-year study period. All tested isolates were susceptible to linezolid. Resistance to trimethoprim-sulfamethoxazole (TMP-SMX) was rare (2%) except among Nocardia pseudobrasiliensis (31%) strains and strains of the N. transvalensis complex (19%). Imipenem susceptibility varied for N. cyriacigeorgica and N. farcinica, as did ceftriaxone susceptibility of the N. nova complex. Resistance to more than one of the most commonly used drugs (amikacin, ceftriaxone, TMP-SMX, and imipenem) was highest for N. pseudobrasiliensis (100%), N. transvalensis complex (83%), N. farcinica (68%), N. puris (57%), N. brasiliensis (51%), N. aobensis (50%), and N. amikacinitolerans (43%). Thus, while antimicrobial resistance can often be predicted, susceptibility testing should still be considered when combination therapy is warranted, for less well characterized species or those with variable susceptibility profiles, and for patients with TMP-SMX intolerance.

Poxvirus Host Range Genes and Virus-Host Spectrum: A Critical Review.

Science.gov (United States)

Oliveira, Graziele Pereira; Rodrigues, Rodrigo Araújo Lima; Lima, Maurício Teixeira; Drumond, Betânia Paiva; Abrahão, Jônatas Santos

2017-11-07

The Poxviridae family is comprised of double-stranded DNA viruses belonging to nucleocytoplasmic large DNA viruses (NCLDV). Among the NCLDV, poxviruses exhibit the widest known host range, which is likely observed because this viral family has been more heavily investigated. However, relative to each member of the Poxviridae family, the spectrum of the host is variable, where certain viruses can infect a large range of hosts, while others are restricted to only one host species. It has been suggested that the variability in host spectrum among poxviruses is linked with the presence or absence of some host range genes. Would it be possible to extrapolate the restriction of viral replication in a specific cell lineage to an animal, a far more complex organism? In this study, we compare and discuss the relationship between the host range of poxvirus species and the abundance/diversity of host range genes. We analyzed the sequences of 38 previously identified and putative homologs of poxvirus host range genes, and updated these data with deposited sequences of new poxvirus genomes. Overall, the term host range genes might not be the most appropriate for these genes, since no correlation between them and the viruses' host spectrum was observed, and a change in nomenclature should be considered. Finally, we analyzed the evolutionary history of these genes, and reaffirmed the occurrence of horizontal gene transfer (HGT) for certain elements, as previously suggested. Considering the data presented in this study, it is not possible to associate the diversity of host range factors with the amount of hosts of known poxviruses, and this traditional nomenclature creates misunderstandings.

Poxvirus Host Range Genes and Virus–Host Spectrum: A Critical Review

Science.gov (United States)

Oliveira, Graziele Pereira; Rodrigues, Rodrigo Araújo Lima; Lima, Maurício Teixeira; Drumond, Betânia Paiva; Abrahão, Jônatas Santos

2017-01-01

The Poxviridae family is comprised of double-stranded DNA viruses belonging to nucleocytoplasmic large DNA viruses (NCLDV). Among the NCLDV, poxviruses exhibit the widest known host range, which is likely observed because this viral family has been more heavily investigated. However, relative to each member of the Poxviridae family, the spectrum of the host is variable, where certain viruses can infect a large range of hosts, while others are restricted to only one host species. It has been suggested that the variability in host spectrum among poxviruses is linked with the presence or absence of some host range genes. Would it be possible to extrapolate the restriction of viral replication in a specific cell lineage to an animal, a far more complex organism? In this study, we compare and discuss the relationship between the host range of poxvirus species and the abundance/diversity of host range genes. We analyzed the sequences of 38 previously identified and putative homologs of poxvirus host range genes, and updated these data with deposited sequences of new poxvirus genomes. Overall, the term host range genes might not be the most appropriate for these genes, since no correlation between them and the viruses’ host spectrum was observed, and a change in nomenclature should be considered. Finally, we analyzed the evolutionary history of these genes, and reaffirmed the occurrence of horizontal gene transfer (HGT) for certain elements, as previously suggested. Considering the data presented in this study, it is not possible to associate the diversity of host range factors with the amount of hosts of known poxviruses, and this traditional nomenclature creates misunderstandings. PMID:29112165

What difference does it make if viruses are strain-, rather than species-specific?

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Tron Frede Thingstad

2015-04-01

Full Text Available Theoretical work has suggested an important role of lytic viruses in controlling the diversity of their prokaryotic hosts. Yet, providing strong experimental or observational support (or refutation for this has proven evasive. Such models have usually assumed host groups to correspond to the species level, typically represented by 16S rDNA data. Recent model developments take into account the resolution of species into strains with differences in their susceptibility to viral attack. With strains as the host groups, the models will have explicit viral control of abundance at strain level, combined with explicit predator or resource control at community level, but the direct viral control at species level then disappears. Abundance of a species therefore emerges as the combination of how many strains, and at what abundance, this species can establish in competition with other species from a seeding community. We here discuss how species diversification and strain diversification may introduce competitors and defenders, respectively, and that the balance between the two may be a factor in the control of species diversity in mature natural communities. These models suggest that the balance between the two may be a factor in the control of species diversity in mature natural communities. These models can also give a dominance of individuals from strains with high cost of resistance; suggesting that the high proportion of dormant cells among pelagic heterotrophic prokaryotes may reflect their need for expensive defense rather than the lack of suitable growth substrates in their environment.

Host selection by the shiny cowbird

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Wiley, J.W.

1988-01-01

Factors important in Shiny Cowbird (Molothrus bonariensis) host selection were examined within the mangrove community in Puerto Rico. Cowbirds did not parasitize birds in proportion to their abundance. The cowbird breeding season coincided with those of its major hosts, which were 'high-quality' foster species (i.e., species that fledge .gtoreq. 55% of cowbirds hatched: Yellow Warbler, Dendroica petechia; Yellow-shouldered Blackbird, Agelaius xanthomus; Black-whiskered Vireo, Vireo altiloquus; Black-cowled Oriole, Icterus dominicensis; Peurto Rican Flycatcher, Myiarchus antillarum; Troupial, Icterus icterus), and did not extend into other periods even though nests of 'low-quality: species (i.e., species that fledge < 55% of cowbird chicks that hatched: Bronze Mannikin, Lonchura cucullata; Greater Antillean Grackle, Quiscalus niger; Gray Kingbird, Tyrannus dominicensis; Northern Mockingbird, Mimus polyglottos; Red-legged Thrush, Turdus plumbeus) were available. Shiny Cowbird food habits and egg size were similar to those of their hosts, suggesting that cowbirds choose hosts partly on the basis of this combination. Cowbirds located host nests primarily by cryptically watching activities of birds in likely habitats. Other nest locating strategies were active searching of suitable habitat and 'flushing' of hosts by the cowbird's noisy approach. Cowbirds closely monitored nest status with frequent visits that peaked on the host's first day of egg laying. Hosts using covered nests (e.g., cavities, domed nests) were as vulnerable to cowbird parasitism as those building open nests.

Lymphotropism and host responses during acute wild-type canine distemper virus infections in a highly susceptible natural host

DEFF Research Database (Denmark)

Nielsen, Line; Søgaard, Mette; Jensen, Trine Hammer

2009-01-01

The mechanisms behind the in vivo virulence of immunosuppressive wild-type Morbillivirus infections are still not fully understood. To investigate lymphotropism and host responses we have selected the natural host model of canine distemper virus (CDV) infection in mink. This model displays...

Antifungal susceptibility testing of Aspergillus species complex in the Clinical Laboratory: how to do it, when to do it, and how to interpret it

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Esther Manso

2014-12-01

Full Text Available The emergence of drug resistance in fungal pathogens has a profound impact on human health given limited number of antifungal drugs. Antifungal resistance in Aspergillus spp. infection can be encountered in the antifungal drug-exposed patient due to selection of intrinsically resistant species or isolates with acquired resistance belonging to species that are normally susceptible. Resistance to triazoles is not common in Aspergillus spp., however, triazole resistance in A. fumigatus appears to be increasing in several European countries in recent years and can be clinically relevant. The Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing have developed breakpoints and epidemiological cutoff values that are now established for Aspergillus spp. Clinical microbiology laboratories will be employed commercial susceptibility assays, rather than reference broth microdilution methods and comparative studies are particularly important.

Species coextinctions and the biodiversity crisis.

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Koh, Lian Pin; Dunn, Robert R; Sodhi, Navjot S; Colwell, Robert K; Proctor, Heather C; Smith, Vincent S

2004-09-10

To assess the coextinction of species (the loss of a species upon the loss of another), we present a probabilistic model, scaled with empirical data. The model examines the relationship between coextinction levels (proportion of species extinct) of affiliates and their hosts across a wide range of coevolved interspecific systems: pollinating Ficus wasps and Ficus, parasites and their hosts, butterflies and their larval host plants, and ant butterflies and their host ants. Applying a nomographic method based on mean host specificity (number of host species per affiliate species), we estimate that 6300 affiliate species are "coendangered" with host species currently listed as endangered. Current extinction estimates need to be recalibrated by taking species coextinctions into account.

Repetitive immunization enhances the susceptibility of mice to peripherally administered prions.

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Juliane Bremer

Full Text Available The susceptibility of humans and animals to prion infections is determined by the virulence of the infectious agent, by genetic modifiers, and by hitherto unknown host and environmental risk factors. While little is known about the latter two, the activation state of the immune system was surmised to influence prion susceptibility. Here we administered prions to mice that were repeatedly immunized by two initial injections of CpG oligodeoxynucleotides followed by repeated injections of bovine serum albumin/alum. Immunization greatly reduced the required dosage of peripherally administered prion inoculum necessary to induce scrapie in 50% of mice. No difference in susceptibility was observed following intracerebral prion challenge. Due to its profound impact onto scrapie susceptibility, the host immune status may determine disease penetrance after low-dose prion exposure, including those that may give rise to iatrogenic and variant Creutzfeldt-Jakob disease.

Host-bacterial interplay in periodontal disease

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Rudrakshi Chickanna

2015-01-01

Full Text Available A literature search was performed using MEDLINE (PubMed and other electronic basis from 1991 to 2014. Search included books and journals based on the systematic and critical reviews, in vitro and in vivo clinical studies on molecular basis of host microbial interactions. Clearly, an understanding of the host susceptibility factor in addition to microbial factors by elucidating the molecular basis offers opportunity for therapeutic manipulation of advancing periodontal destruction. One of the hallmarks of pathogenesis is the ability of pathogenic organisms to invade surrounding tissues and to evade the host defence. This paper focuses the general overview of molecular mechanisms involved in the microbiota and host response to bacterial inimical behavior in periodontics.

Ligophorus species (Monogenea: Ancyrocephalidae) from Mugil cephalus (Teleostei: Mugilidae) off Morocco with the description of a new species and remarks about the use of Ligophorus spp. as biological markers of host populations.

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El Hafidi, Fouzia; Rkhami, Ouafae Berrada; de Buron, Isaure; Durand, Jean-Dominique; Pariselle, Antoine

2013-11-01

Gill monogenean species of Ligophorus Euzet et Suriano, 1977 were studied from the teleost Mugil cephalus Linneaus (Mugilidae) from the Mediterranean and Atlantic coasts of Morocco. We report the presence of L. mediterraneus from both the Mediterranean and Atlantic coast and L. cephali and L. maroccanus sp. n. from the Atlantic coast only. The latter species, which is described herein as new, resembles L. guanduensis but differs from this species mainly in having a shorter penis compared to the accessory piece, a proportionally longer extremity of the accessory piece and a less developed heel. The utility of Ligophorus spp. as markers of cryptic species of the complex M. cephalus is discussed in the context of species diversity and geographical distribution of these monogeneans on this host around the world. Presence of different species of Ligophorus on M. cephalus sensu stricto from the Atlantic and Mediterranean coast of Morocco demonstrates the usefulness of these species as fine resolution markers of genetic populations of their host, which are known to inhabit those coasts.

Beyond Candida albicans: Mechanisms of immunity to non-albicans Candida species

Science.gov (United States)

Whibley, Natasha; Gaffen, Sarah L.

2015-01-01

The fungal genus Candida encompasses numerous species that inhabit a variety of hosts, either as commensal microbes and/or pathogens. Candida species are a major cause of fungal infections, yet to date there are no vaccines against Candida or indeed any other fungal pathogen. Our knowledge of immunity to Candida mainly comes from studies on C. albicans, the most frequent species associated with disease. However, non-albicans Candida (NAC) species also cause disease and their prevalence is increasing. Although research into immunity to NAC species is still at an early stage, it is becoming apparent that immunity to C. albicans differs in important ways from non-albicans species, with important implications for treatment, therapy and predicted demographic susceptibility. This review will discuss the current understanding of immunity to NAC species in the context of immunity to C. albicans, and highlight as-yet unanswered questions. PMID:26276374

Antimicrobial Susceptibility Patterns of Brachyspira Species Isolated in Taiwan.

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Yeh, Jih-Ching; Lo, Dan-Yuan; Chang, Shao-Kuang; Kuo, Hung-Chih

2018-03-13

Some members of the Brachyspira genus cause diseases such as swine dysentery (SD) and porcine intestinal (or colonic) spirochetosis. Severe economic losses are caused by decreased feed intake and increased feed conversion ratio, as well as costs associated with treatment and death. A loss of clinical efficacy of some antimicrobial agents authorized for treating SD has been observed in many countries. The aim of this study was to analyze the antimicrobial susceptibility of Brachyspira isolated from Taiwan and to investigate the mechanism of decreased susceptibility to macrolides. A total of 55 Brachyspira isolates obtained from the grower-finisher period were evaluated in this study. These isolates included B. hyodysenteriae (n = 37), B. murdochii (n = 11), B. pilosicoli (n = 5), B. intermedia (n = 1), and B. innocens (n = 1). Antimicrobial susceptibility testing was performed to examine 12 selected antimicrobial agents. The results showed that the 50% and 90% minimum inhibitory concentration (MIC) values of the tested macrolides were all >256 μg/ml. The MIC 50 of lincomycin, tiamulin, carbadox, olaquindox, ampicillin, amoxicillin, doxycycline, oxytetracycline, and gentamicin were 32, 1, ≤0.125, ≤0.125, 0.5, 0.25, 2, 2, and 2 μg/ml. The genetic basis of the decreased susceptibility to tylosin and lincomycin in Brachyspira spp. was investigated and the results showed a possible connection to the mutations at position A2058 and G2032 of the 23S rRNA gene. These findings demonstrated that, in Taiwan, there may be a decrease in susceptibility of Brachyspira spp. to antimicrobials commonly used for the treatment of SD.

Differential host growth regulation by the solitary endoparasitoid, Meteorus pulchricornis in two hosts of greatly differing mass.

Science.gov (United States)

Harvey, Jeffrey A; Sano, Takeshi; Tanaka, Toshiharu

2010-09-01

Solitary koinobiont endoparasitoids generally reduce the growth of their hosts by a significant amount compared with healthy larvae. Here, we compared the development and host usage strategies of the solitary koinobiont endoparasitoid, Meteorus pulchricornis, when developing in larvae of a large host species (Mythimna separata) and a much smaller host species (Plutella xylostella). Caterpillars of M. separata were parasitized as L2 and P. xylostella as L3, when they weighed approximately 2mg. The growth of parasitized M. separata larvae was reduced by almost 95% compared with controls, whereas parasitized P. xylostella larvae grew some 30% larger than controls. Still, adult wasps emerging from M. separata larvae were almost twice as large as wasps emerging from P. xylostella larvae, had larger egg loads after 5 days and produced more progeny. Survival to eclosion was also higher on M. separata than on P. xylostella, although parasitoids developed significantly faster when developing on P. xylostella. Our results provide evidence that koinobionts are able to differentially regulate the growth of different host species. However, there are clearly also limitations in the ability of parasitoids to regulate phenotypic host traits when size differences between different host species are as extreme as demonstrated here.

Genome-Wide Comparison of Magnaporthe Species Reveals a Host-Specific Pattern of Secretory Proteins and Transposable Elements.

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Meghana Deepak Shirke

Full Text Available Blast disease caused by the Magnaporthe species is a major factor affecting the productivity of rice, wheat and millets. This study was aimed at generating genomic information for rice and non-rice Magnaporthe isolates to understand the extent of genetic variation. We have sequenced the whole genome of the Magnaporthe isolates, infecting rice (leaf and neck, finger millet (leaf and neck, foxtail millet (leaf and buffel grass (leaf. Rice and finger millet isolates infecting both leaf and neck tissues were sequenced, since the damage and yield loss caused due to neck blast is much higher as compared to leaf blast. The genome-wide comparison was carried out to study the variability in gene content, candidate effectors, repeat element distribution, genes involved in carbohydrate metabolism and SNPs. The analysis of repeat element footprints revealed some genes such as naringenin, 2-oxoglutarate 3-dioxygenase being targeted by Pot2 and Occan, in isolates from different host species. Some repeat insertions were host-specific while other insertions were randomly shared between isolates. The distributions of repeat elements, secretory proteins, CAZymes and SNPs showed significant variation across host-specific lineages of Magnaporthe indicating an independent genome evolution orchestrated by multiple genomic factors.

Antifungal susceptibility and phylogeny of opportunistic members of the order mucorales.

Science.gov (United States)

Vitale, Roxana G; de Hoog, G Sybren; Schwarz, Patrick; Dannaoui, Eric; Deng, Shuwen; Machouart, Marie; Voigt, Kerstin; van de Sande, Wendy W J; Dolatabadi, Somayeh; Meis, Jacques F; Walther, Grit

2012-01-01

The in vitro susceptibilities of 66 molecularly identified strains of the Mucorales to eight antifungals (amphotericin B, terbinafine, itraconazole, posaconazole, voriconazole, caspofungin, micafungin, and 5-fluorocytosine) were tested. Molecular phylogeny was reconstructed based on the nuclear ribosomal large subunit to reveal taxon-specific susceptibility profiles. The impressive phylogenetic diversity of the Mucorales was reflected in susceptibilities differing at family, genus, and species levels. Amphotericin B was the most active drug, though somewhat less against Rhizopus and Cunninghamella species. Posaconazole was the second most effective antifungal agent but showed reduced activity in Mucor and Cunninghamella strains, while voriconazole lacked in vitro activity for most strains. Genera attributed to the Mucoraceae exhibited a wide range of MICs for posaconazole, itraconazole, and terbinafine and included resistant strains. Cunninghamella also comprised strains resistant to all azoles tested but was fully susceptible to terbinafine. In contrast, the Lichtheimiaceae completely lacked strains with reduced susceptibility for these antifungals. Syncephalastrum species exhibited susceptibility profiles similar to those of the Lichtheimiaceae. Mucor species were more resistant to azoles than Rhizopus species. Species-specific responses were obtained for terbinafine where only Rhizopus arrhizus and Mucor circinelloides were resistant. Complete or vast resistance was observed for 5-fluorocytosine, caspofungin, and micafungin. Intraspecific variability of in vitro susceptibility was found in all genera tested but was especially high in Mucor and Rhizopus for azoles and terbinafine. Accurate molecular identification of etiologic agents is compulsory to predict therapy outcome. For species of critical genera such as Mucor and Rhizopus, exhibiting high intraspecific variation, susceptibility testing before the onset of therapy is recommended.

New host records of Aglaomelissa duckei and a compilation of host associations of Ericrocidini bees (Hymenoptera: Apidae

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Léo C. Rocha-Filho

2009-06-01

Full Text Available For the first time, confirmed host records are reported for the monotypic Ericrocidini genus Aglaomelissa Snelling & Brooks, 1985. Aglaomelissa duckei (Friese, 1906 emerged from trap-nests of Centris (Heterocentris analis (Fabricius, 1804 and C. (Heterocentris terminata Smith, 1874 from two sites in the Brazilian Amazonian region. The parasitism ratio caused by A. duckei was high, varying from 80 to 100% of the brood cells in a single trap-nest. Also, a compilation of the known host records for the species of Ericrocidini is presented and host-parasite associations are discussed. Host associations are known for seven of the 11 genera and about 17 of the 42 species of the tribe, involving a total of 34 confirmed or putative host species of Centridini bees. All species of the tribe are known to attack only nests of Centris Fabricius, 1804, except Mesoplia rufipes (Perty, 1833 that also parasitizes nests of Epicharis Klug, 1807. Although the phylogenetic relationships within Ericrocidini and among the subgenera of Centris are not well resolved, the current knowledge of the host-parasite associations points to a relatively high degree of specificity and possible coevolution between them.

The paralogous salivary anti-complement proteins IRAC I and IRAC II encoded by Ixodes ricinus ticks have broad and complementary inhibitory activities against the complement of different host species.

Science.gov (United States)

Schroeder, Hélène; Daix, Virginie; Gillet, Laurent; Renauld, Jean-Christophe; Vanderplasschen, Alain

2007-02-01

Several observations suggest that inhibition of the host complement alternative pathway by Ixodes tick saliva is crucial to achieve blood feeding. We recently described two paralogous anti-complement proteins called Ixodes ricinus anti-complement (IRAC) proteins I and II co-expressed in I. ricinus salivary glands. Phylogenetic analyses suggested that these sequences were diversifying by a process of positive Darwinian selection, possibly leading to molecules with different biological properties. In the present study, we tested the hypothesis that each paralogue may have different inhibitory activities against the complement of different natural host species, thereby contributing to broaden the host range of I. ricinus ticks. IRAC I and IRAC II were tested against the complement of eight I. ricinus natural host species (six mammals and two birds). The results demonstrate that IRAC I and IRAC II have broad and complementary inhibition activities against the complement of different host species. This report is the first description of paralogous anti-complement molecules encoded by a pathogen with broad and complementary inhibitory activities against the complement of different host species.

Antifungal susceptibility testing of Candida species isolated from the immunocompromised patients admitted to ten university hospitals in Iran: comparison of colonizing and infecting isolates.

Science.gov (United States)

Badiee, Parisa; Badali, Hamid; Boekhout, Teun; Diba, Kambiz; Moghadam, Abdolkarim Ghadimi; Hossaini Nasab, Ali; Jafarian, Hadis; Mohammadi, Rasoul; Mirhendi, Hossein; Najafzadeh, Mohammad Javad; Shamsizadeh, Ahmad; Soltani, Jafar

2017-11-21