Poxviruses and the Evolution of Host Range and Virulence

PubMed Central

Haller, Sherry L.; Peng, Chen; McFadden, Grant; Rothenburg, Stefan

2013-01-01

Poxviruses as a group can infect a large number of animals. However, at the level of individual viruses, even closely related poxviruses display highly diverse host ranges and virulence. For example, variola virus, the causative agent of smallpox, is human-specific and highly virulent only to humans, whereas related cowpox viruses naturally infect a broad spectrum of animals and only cause relatively mild disease in humans. The successful replication of poxviruses depends on their effective manipulation of the host antiviral responses, at the cellular-, tissue- and species-specific levels, which constitutes a molecular basis for differences in poxvirus host range and virulence. A number of poxvirus genes have been identified that possess host range function in experimental settings, and many of these host range genes target specific antiviral host pathways. Herein, we review the biology of poxviruses with a focus on host range, zoonotic infections, virulence, genomics and host range genes as well as the current knowledge about the function of poxvirus host range factors and how their interaction with the host innate immune system contributes to poxvirus host range and virulence. We further discuss the evolution of host range and virulence in poxviruses as well as host switches and potential poxvirus threats for human and animal health. PMID:24161410

Gabbroic xenoliths from the northern Gorda Ridge: implications for magma chamber processes under slow spreading centers

USGS Publications Warehouse

Davis, A.S.; Clague, D.A.

1990-01-01

Abundant gabbroic xenoliths in porphyritic pillow basalt were dredged from the northern Gorda Ridge. The host lava is a moderately fractionated, normal mid-ocean ridge basalt with a heterogeneous glass rind (Mg numbers 56-60). Other lavas in the vicinity range from near primary (Mg number 69) to fractionated (Mg number 56). On the basis of textures and mineral compositions, the xenoliths are divided into five types. The xenoliths are not cognate to the host lava, but they are genetically related. Chemistry of mineral phases in conjunction with textural features suggests that the xenoliths formed in different parts of a convecting magma chamber that underwent a period of closed system fractionation. The chamber was filled with a large proportion of crystalline mush when new, more primitive, and less dense magma was injected and mixed incompletely with the contents in the chamber, forming the hybrid host lava. -from Authors

A Model of an Integrated Immune System Pathway in Homo sapiens and Its Interaction with Superantigen Producing Expression Regulatory Pathway in Staphylococcus aureus: Comparing Behavior of Pathogen Perturbed and Unperturbed Pathway

PubMed Central

Tomar, Namrata; De, Rajat K.

2013-01-01

Response of an immune system to a pathogen attack depends on the balance between the host immune defense and the virulence of the pathogen. Investigation of molecular interactions between the proteins of a host and a pathogen helps in identifying the pathogenic proteins. It is necessary to understand the dynamics of a normally behaved host system to evaluate the capacity of its immune system upon pathogen attack. In this study, we have compared the behavior of an unperturbed and pathogen perturbed host system. Moreover, we have developed a formalism under Flux Balance Analysis (FBA) for the optimization of conflicting objective functions. We have constructed an integrated pathway system, which includes Staphylococcal Superantigen (SAg) expression regulatory pathway and TCR signaling pathway of Homo sapiens. We have implemented the method on this pathway system and observed the behavior of host signaling molecules upon pathogen attack. The entire study has been divided into six different cases, based on the perturbed/unperturbed conditions. In other words, we have investigated unperturbed and pathogen perturbed human TCR signaling pathway, with different combinations of optimization of concentrations of regulatory and signaling molecules. One of these cases has aimed at finding out whether minimization of the toxin production in a pathogen leads to the change in the concentration levels of the proteins coded by TCR signaling pathway genes in the infected host. Based on the computed results, we have hypothesized that the balance between TCR signaling inhibitory and stimulatory molecules can keep TCR signaling system into resting/stimulating state, depending upon the perturbation. The proposed integrated host-pathogen interaction pathway model has accurately reflected the experimental evidences, which we have used for validation purpose. The significance of this kind of investigation lies in revealing the susceptible interaction points that can take back the Staphylococcal Enterotoxin (SE)-challenged system within the range of normal behavior. PMID:24324645

Novel Coupled Thermochronometric and Geochemical Investigation of Blind Geothermal Resources in Fault-Controlled Dilational Corners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stockli, Daniel

Geothermal plays in extensional and transtensional tectonic environments have long been a major target in the exploration of geothermal resources and the Dixie Valley area has served as a classic natural laboratory for this type of geothermal plays. In recent years, the interactions between normal faults and strike-slip faults, acting either as strain relay zones have attracted significant interest in geothermal exploration as they commonly result in fault-controlled dilational corners with enhanced fracture permeability and thus have the potential to host blind geothermal prospects. Structural ambiguity, complications in fault linkage, etc. often make the selection for geothermal exploration drilling targetsmore » complicated and risky. Though simplistic, the three main ingredients of a viable utility-grade geothermal resource are heat, fluids, and permeability. Our new geological mapping and fault kinematic analysis derived a structural model suggest a two-stage structural evolution with (a) middle Miocene N -S trending normal faults (faults cutting across the modern range), - and tiling Olio-Miocene volcanic and sedimentary sequences (similar in style to East Range and S Stillwater Range). NE-trending range-front normal faulting initiated during the Pliocene and are both truncating N-S trending normal faults and reactivating some former normal faults in a right-lateral fashion. Thus the two main fundamental differences to previous structural models are (1) N-S trending faults are pre-existing middle Miocene normal faults and (2) these faults are reactivated in a right-later fashion (NOT left-lateral) and kinematically linked to the younger NE-trending range-bounding normal faults (Pliocene in age). More importantly, this study provides the first constraints on transient fluid flow through the novel application of apatite (U-Th)/He (AHe) and 4He/ 3He thermochronometry in the geothermally active Dixie Valley area in Nevada.« less

Marrow transplantation in the treatment of a murine heritable hemolytic anemia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barker, J.E.; McFarland-Starr, E.C.

1989-05-15

Mice with hemolytic anemia, sphha/sphha, have extremely fragile RBCs with a lifespan of approximately one day. Neither splenectomy nor simple transplantation of normal marrow after lethal irradiation cures the anemia but instead causes rapid deterioration and death of the mutant unless additional prophylactic procedures are used. In this report, we show that normal marrow transplantation preceded by sublethal irradiation increases but does not normalize RBC count. The mutant RBCs but not all the WBCs are replaced by donor cells. Splenectomy of the improved recipient causes a dramatic decrease in RBC count, indicating that the mutant spleen is a site ofmore » donor-origin erythropoiesis as well as of RBC destruction. Injections of iron dextran did not improve RBC counts. Transplantation of primary recipient marrow cells into a secondary host with a heritable stem cell deficiency (W/Wv) corrects the defect caused by residence of the normal cells in the sphha/sphha host. The original +/+ donor cells replace the RBCs of the secondary host, and the RBC count is normalized. Results indicate that the environment in the sphha/sphha host is detrimental to normal (as well as mutant) erythroid cells but the restriction is not transmitted.« less

Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

PubMed Central

Johnson, Timothy J.; Ricke, Steven C.; Nayak, Rajesh; Danzeisen, Jessica

2013-01-01

SUMMARY Enteric pathogens such as Salmonella enterica cause significant morbidity and mortality. S. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts. S. enterica serovars such as S. Typhi, S. Dublin, and S. Gallinarum have a restricted host range, in which they are typically associated with one or a few host species, while S. Enteritidis and S. Typhimurium have broad host ranges. This review examines how S. enterica has evolved through adaptation to different host environments, especially as related to the chicken host, and continues to be an important human pathogen. Several factors impact host range, and these include the acquisition of genes via horizontal gene transfer with plasmids, transposons, and phages, which can potentially expand host range, and the loss of genes or their function, which would reduce the range of hosts that the organism can infect. S. Gallinarum, with a limited host range, has a large number of pseudogenes in its genome compared to broader-host-range serovars. S. enterica serovars such as S. Kentucky and S. Heidelberg also often have plasmids that may help them colonize poultry more efficiently. The ability to colonize different hosts also involves interactions with the host's immune system and commensal organisms that are present. Thus, the factors that impact the ability of Salmonella to colonize a particular host species, such as chickens, are complex and multifactorial, involving the host, the pathogen, and extrinsic pressures. It is the interplay of these factors which leads to the differences in host ranges that we observe today. PMID:24296573

Detection of chromosomal abnormalities by fluorescent in-situ hybridization in immotile viable spermatozoa determined by hypo-osmotic sperm swelling test.

PubMed

Zeyneloglu, H B; Baltaci, V; Ege, S; Haberal, A; Batioglu, S

2000-04-01

If randomly selected immotile spermatozoa are used for intracytoplasmic sperm injection (ICSI), pregnancy rates are significantly decreased. The hypo-osmotic swelling test (HOST) is the only method available to detect the viable, but immotile spermatozoa for ICSI. However, evidence is still lacking for the chromosomal abnormalities for the normal-looking, but immotile spermatozoa positive for HOST. Sperm samples from 20 infertile men with normal chromosomal constitution were obtained. After Percoll separation, morphologically normal but immotile spermatozoa were transported individually into HOST solution for 1 min using micropipettes. Cells that showed tail curling with swelling in HOST were then transferred back into human tubal fluid solution to allow reversal of swelling. These sperm cells were fixed and processed for the multi-colour fluorescence in-situ hybridization (FISH) for chromosomes X, Y and 18. The same FISH procedure was applied for the motile spermatozoa from the same cohort, which formed the control group. The average aneuploidy rates were 1.70 and 1.54% in 1000 HOST positive immotile and motile spermatozoa respectively detected by FISH for each patient. Our results indicate that morphologically normal, immotile but viable spermatozoa have an aneuploidy rate similar to that of normal motile spermatozoa.

A RECENT HOST RANGE EXPANSION IN JUNONIA COENIA HÜBNER (NYMPHALIDAE): OVIPOSITION PREFERENCE, SURVIVAL, GROWTH, AND CHEMICAL DEFENSE.

PubMed

Camara, Mark D

1997-06-01

This paper reports on an investigation of two populations of Junonia coenia, the buckeye butterfly, one that feeds on the species' typical host plant (Plantago lanceolata) and one that utilizes a novel host plant (Kickxia elatine). I examined these populations for local adaptive responses in terms of oviposition behavior, growth, and chemical defense, on both P. lanceolata and K. elatine. In addition, I examined the genetic architecture underlying these traits using a full-sib quantitative genetic analysis. I found that a significant majority of females prefer the host plant species found at their collection sites in oviposition tests, but that there is no evidence that they are locally adapted in growth performance, as measured by fifth-instar and pupal weights and development times. Neither are there correlations between oviposition preferences of females and the growth performance or levels of chemical defense of their offspring. The two populations studied do, however, show specialization in terms of the levels of chemical defense they sequester from their host plants. I argue that these results indicate that natural enemies are the normal barriers to host range expansion in this oligophagous herbivore because a breakdown in those barriers results in genetic changes that enhance resistance to predation. This is despite the fact that adaptive responses in physiology are unlikely to be limited by a lack of genetic variability; the genetic architecture among traits would be conducive to specialization in growth performance; and there are costs to chemical defense in this species. All these conditions would tend to argue that J. coenia harbors considerable potential for coevolutionary interactions with its chemically defended hosts, but this potential is not realized, probably because natural selection on diet breadth by natural enemies is much stronger than selection from host plants in this system. © 1997 The Society for the Study of Evolution.

Host range and cell cycle activation properties of polyomavirus large T-antigen mutants defective in pRB binding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freund, R.; Bauer, P.H.; Benjamin, T.L.

1994-11-01

The authors have examined the growth properties of polyomavirus large T-antigen mutants that ar unable to bind pRB, the product of the retinoblastoma tumor suppressor gene. These mutants grow poorly on primary mouse cells yet grow well on NIH 3T3 and other established mouse cell lines. Preinfection of primary baby mouse kidney (BMK) epithelial cells with wild-type simian virus 40 renders these cells permissive to growth of pRB-binding polyomavirus mutants. Conversely, NIH 3T3 cells transfected by and expressing wild-type human pRB become nonpermissive. Primary fibroblasts for mouse embryos that carry a homozygous knockout of the RB gene are permissive, whilemore » those from normal littermates are nonpermissive. The host range of polyomavirus pRB-binding mutants is thus determined by expression or lack of expression of functional pRB by the host. These results demonstrate the importance of pRB binding by large T antigen for productive viral infection in primary cells. Failure of pRB-binding mutants to grow well in BMK cells correlates with their failure to induce progression from G{sub 0} or G{sub 1} through the S phase of the cell cycle. Time course studies show delayed synthesis and lower levels of accumulation of large T antigen, viral DNA, and VP1 in mutant compared with wild-type virus-infected BMK cells. These results support a model in which productive infection by polyomavirus in normal mouse cells is tightly coupled to the induction and progression of the cell cycle. 48 refs., 6 figs., 5 tabs.« less

Poxvirus Host Range Genes and Virus–Host Spectrum: A Critical Review

PubMed Central

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

Gamma-Ray Burst Host Galaxies Have "Normal" Luminosities.

PubMed

Schaefer

2000-04-10

The galactic environment of gamma-ray bursts can provide good evidence about the nature of the progenitor system, with two old arguments implying that the burst host galaxies are significantly subluminous. New data and new analysis have now reversed this picture: (1) Even though the first two known host galaxies are indeed greatly subluminous, the next eight hosts have absolute magnitudes typical for a population of field galaxies. A detailed analysis of the 16 known hosts (10 with redshifts) shows them to be consistent with a Schechter luminosity function with R*=-21.8+/-1.0, as expected for normal galaxies. (2) Bright bursts from the Interplanetary Network are typically 18 times brighter than the faint bursts with redshifts; however, the bright bursts do not have galaxies inside their error boxes to limits deeper than expected based on the luminosities for the two samples being identical. A new solution to this dilemma is that a broad burst luminosity function along with a burst number density varying as the star formation rate will require the average luminosity of the bright sample (>6x1058 photons s-1 or>1.7x1052 ergs s-1) to be much greater than the average luminosity of the faint sample ( approximately 1058 photons s-1 or approximately 3x1051 ergs s-1). This places the bright bursts at distances for which host galaxies with a normal luminosity will not violate the observed limits. In conclusion, all current evidence points to gamma-ray burst host galaxies being normal in luminosity.

Recombinant glucose uptake system

DOEpatents

Ingrahm, Lonnie O.; Snoep, Jacob L.; Arfman, Nico

1997-01-01

Recombinant organisms are disclosed that contain a pathway for glucose uptake other than the pathway normally utilized by the host cell. In particular, the host cell is one in which glucose transport into the cell normally is coupled to PEP production. This host cell is transformed so that it uses an alternative pathway for glucose transport that is not coupled to PEP production. In a preferred embodiment, the host cell is a bacterium other than Z. mobilis that has been transformed to contain the glf and glk genes of Z. mobilis. By uncoupling glucose transport into the cell from PEP utilization, more PEP is produced for synthesis of products of commercial importance from a given quantity of biomass supplied to the host cells.

Recurrent Pneumocystis Pneumonia with Uncommon Radiographic Presentation.

PubMed

Dixit, Ayushi; Shariff, Rayhan; Gandham, Sherleen; Bhavsar, Ravi; Mantis, Jazila; Vapnyar, Victoria

2018-01-29

Pneumocystis carinii pneumonia (PCP) is a common opportunistic infection of the pulmonary parenchyma seen in the immunocompromised host. The clinical presentation and radiographic findings are varied, with the latter ranging from normal to bilateral ground-glass opacities with cyst formation. We present a case of a 46-year-old woman with a history of human immunodeficiency virus (HIV) with multiple treated prior episodes of PCP, who was found to have an impressive presentation on high-resolution chest computed tomography (HRCT).

Getting there and around: Host range oscillations during colonization of the Canary Islands by the parasitic nematode Spauligodon.

PubMed

Jorge, Fátima; Perera, Ana; Poulin, Robert; Roca, Vicente; Carretero, Miguel A

2018-01-01

Episodes of expansion and isolation in geographic range over space and time, during which parasites have the opportunity to expand their host range, are linked to the development of host-parasite mosaic assemblages and parasite diversification. In this study, we investigated whether island colonization events lead to host range oscillations in a taxon of host-specific parasitic nematodes of the genus Spauligodon in the Canary Islands. We further investigated whether range oscillations also resulted in shifts in host breadth (i.e., specialization), as expected for parasites on islands. Parasite phylogeny and divergence time estimates were inferred from molecular data with Bayesian methods. Host divergence times were set as calibration priors after a priori evaluation with a global-fit method of which individual host-parasite associations likely represent cospeciation links. Parasite colonization history was reconstructed, followed by an estimation of oscillation events and specificity level. The results indicate the presence of four Spauligodon clades in the Canary Islands, which originated from at least three different colonization events. We found evidence of host range oscillations to truly novel hosts, which in one case led to higher diversification. Contemporary host-parasite associations show strong host specificity, suggesting that changes in host breadth were limited to the shift period. Lineages with more frequent and wider taxonomic host range oscillations prior to the initial colonization event showed wider range oscillations during colonization and diversification within the archipelago. Our results suggest that a lineage's evolutionary past may be the best indicator of a parasite's potential for future range expansions. © 2017 John Wiley & Sons Ltd.

Prolongation of RBC survival in the hypophysectomized rat.

NASA Technical Reports Server (NTRS)

Landaw, S. A.; Bristol, S. K.

1971-01-01

Red blood cell (RBC) survival was prolonged in hypophysectomized rats. While the rate of random hemolysis was decreased in some hypophysectomized hosts, in all directly injected and cross-transfused hypophysectomized rat hosts, there was a significant prolongation of the phase of senescent death. In contrast, RBCs from hypophysectomized donors survived normally in normal hosts. These experiments are further evidence of a relationship between RBC aging and metabolic rate, and suggest an intimate involvement with the calorigenic hormones.

Novel application of species richness estimators to predict the host range of parasites.

PubMed

Watson, David M; Milner, Kirsty V; Leigh, Andrea

2017-01-01

Host range is a critical life history trait of parasites, influencing prevalence, virulence and ultimately determining their distributional extent. Current approaches to measure host range are sensitive to sampling effort, the number of known hosts increasing with more records. Here, we develop a novel application of results-based stopping rules to determine how many hosts should be sampled to yield stable estimates of the number of primary hosts within regions, then use species richness estimation to predict host ranges of parasites across their distributional ranges. We selected three mistletoe species (hemiparasitic plants in the Loranthaceae) to evaluate our approach: a strict host specialist (Amyema lucasii, dependent on a single host species), an intermediate species (Amyema quandang, dependent on hosts in one genus) and a generalist (Lysiana exocarpi, dependent on many genera across multiple families), comparing results from geographically-stratified surveys against known host lists derived from herbarium specimens. The results-based stopping rule (stop sampling bioregion once observed host richness exceeds 80% of the host richness predicted using the Abundance-based Coverage Estimator) worked well for most bioregions studied, being satisfied after three to six sampling plots (each representing 25 host trees) but was unreliable in those bioregions with high host richness or high proportions of rare hosts. Although generating stable predictions of host range with minimal variation among six estimators trialled, distribution-wide estimates fell well short of the number of hosts known from herbarium records. This mismatch, coupled with the discovery of nine previously unrecorded mistletoe-host combinations, further demonstrates the limited ecological relevance of simple host-parasite lists. By collecting estimates of host range of constrained completeness, our approach maximises sampling efficiency while generating comparable estimates of the number of primary hosts, with broad applicability to many host-parasite systems. Copyright © 2016 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

Origin of Langerhans cells in normal skin and chronic GVHD after hematopoietic stem-cell transplantation.

PubMed

Andani, Rafiq; Robertson, Ivan; Macdonald, Kelli P A; Durrant, Simon; Hill, Geoffrey R; Khosrotehrani, Kiarash

2014-01-01

Chronic graft-versus-host disease (cGVHD) is a common complication following allogeneic stem-cell transplantation (SCT). Past studies have implicated the persistence of host antigen-presenting cells (APCs) in GVHD. Our objective was to determine the frequency of host Langerhans cells (LCs) in normal skin post-SCT and ask if their persistence could predict cGVHD. Biopsies of normal skin from 124 sex-mismatched T-cell-replete allogenic SCT recipients were taken 100 days post-transplant. Patients with acute GVHD and those with <9 months of follow-up were excluded and prospective follow-up information was collected from remaining 22 patients. CD1a staining and X and Y chromosome in-situ hybridization were performed to label LCs and to identify their host or donor origin. At 3 months, 59 ± 5% of LCs were host derived. The density of LCs and the proportion of host-derived LCs were similar between patients that did or did not develop cGVHD. Most LCs in the skin remained of host origin 3 months after SCT regardless of cGVHD status. This finding is in line with the redundant role of LCs in acute GVHD initiation uncovered in recent experimental models. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Performing Comparative Peptidomics Analyses of Salmonella from Different Growth Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adkins, Joshua N.; Mottaz, Heather; Metz, Thomas O.

2010-01-08

Host–pathogen interactions are complex competitions during which both the host and the pathogen adapt rapidly to each other in order for one or the other to survive. Salmonella enterica serovar Typhimurium is a pathogen with a broad host range that causes a typhoid fever-like disease in mice and severe food poisoning in humans. The murine typhoid fever is a systemic infection in which S.typhimurium evades part of the immune system by replicating inside macrophages and other cells. The transition from a foodborne contaminant to an intracellular pathogen must occur rapidly in multiple,ordered steps in order for S. typhimurium to thrivemore » within its host environment. Using S. typhimurium isolated from rich culture conditions and from conditions that mimic the hostile intracellular environment of the host cell, a native low molecular weight protein fraction, or peptidome, was enriched from cell lysates by precipitation with organic solvents. The enriched peptidome was analyzed by both LC–MS/MS and LC–MS-based methods, although several other methods are possible. Pre-fractionation of peptides allowed identification of small proteins and protein degradation products that would normally be overlooked. Comparison of peptides present in lysates prepared from Salmonella grown under different conditions provided a unique insight into cellular degradation processes as well as identification of novel peptides encoded in the genome but not annotated. The overall approach is detailed here as applied to Salmonella and is adaptable to a broad range of biological systems.« less

The Resistance of Certain Tissues to Invasion

PubMed Central

Eisenstein, Reuben; Sorgente, Nino; Soble, Lawrence W.; Miller, Alexander; Kuettner, Klaus E.

1973-01-01

If puppy tissues are explanted onto the chick chorioallantoic membrane, those tissues which normally have a blood supply are rapidly invaded by vascularized mesenchyme of host origin. Hyaline cartilage, a tissue virtually devoid of blood vessels, is impenetrable by proliferating mesenchyme of the host, while calcified cartilage, which normally is vascularized, is penetrable. The stroma of the cornea, another normally avascular tissue, is readily penetrable, but Descemet's membrane forms a barrier to invasion by host tissues. The experimental system used permits the design of experiments in which the study of factors responsible for the resistance of tissues such as cartilage to invasion can be undertaken. ImagesFig 1Fig 2Fig 3Fig 4 PMID:4129060

Treatment of severe neutropenia with high-dose pyridoxine in a patient with chronic graft versus host disease and squamous cell carcinoma: a case report

PubMed Central

2011-01-01

Introduction The differential diagnosis of neutropenia includes medications, infections, autoimmune diseases, and deficiencies of Vitamin B12 and folate. The association of Vitamin B6 deficiency with severe neutropenia is a rare finding. Case presentation A 51-year-old Caucasian woman presented with fever and profound neutropenia (48 neutrophils/uL). Her clinical history included non-Hodgkin lymphoma, in remission following treatment with allogeneic bone marrow transplantation, quiescent chronic graft-versus-host disease, and squamous cell carcinoma of the skin metastatic to cervical lymph nodes. Medications included atenolol, topical clobetasol, Ditropan (oxybutynin), prophylactic voriconazole, prophylactic valganciclovir, Soriatane (acitretin), and Carac (fluorouracil) cream. The bone marrow was hypocellular without metastatic cancer or myelodysplasia. Neutropenia did not respond to stopping medications that have been associated with neutropenia (valganciclovir, voriconazole and Soriatane) or treatment with antibiotics or granulocyte colony stimulating factor. Blood tests revealed absence of antineutrophil antibodies, normal folate and B12 levels, moderate zinc deficiency and severe Vitamin B6 deficiency. Replacement therapy with oral Vitamin B6 restored blood vitamin levels to the normal range and corrected the neutropenia. Her cervical adenopathy regressed clinically and became negative on scintography following Vitamin B6 therapy and normalization of the blood neutrophil count. Conclusion Severe pyridoxine deficiency can lead to neutropenia. Screening for Vitamin B6 deficiency, along with folate and Vitamin B12 levels, is recommended in patients with refractory neutropenia, especially those with possible malabsorption syndromes, or a history of chronic-graft-versus host disease. Severe neutropenia may facilitate progression of squamous cell carcinoma. PMID:21838907

Hydrothermal barite mineralization at Chenarvardeh deposit, Markazi Province, Iran: Evidences from REE geochemistry and fluid inclusions

NASA Astrophysics Data System (ADS)

Ehya, Farhad; Mazraei, Shaghayegh Moalaye

2017-10-01

Barite mineralization occurs at Chenarvardeh deposit as layers and lenses in Upper Eocene volcanic and pyroclastic rocks. The host rocks are intensely saussuritized in most places. Barite is accompanied by calcite, Mn-oxides, galena and malachite as subordinate minerals. The amount of Sr in barites is low and varies between 0.11 and 0.30 wt%. The concentration of Rb, Zr, Y, Ta and Hf is also low (<5 ppm) in barite samples. The amount of total REEs (∑REE) is low in barites, ranging from 7.51 to 30.50 ppm. Chondrite-normalized REE patterns reveal LREE enrichment with respect to HREE, and positive Ce anomalies. Fluid inclusions are common in barite samples, being dominantly from liquid-rich two phase (L + V) type. Salinity values in fluid inclusions range from 9.41 to 18.69 wt% NaCl equivalent with most frequent salinities falling in the range of 10-15 wt% NaCl equivalent. Homogenization temperatures (Th) range between 160 and 220 °C, being the 180-200 °C range as the most common Th interval. A combination of factors, including geologic setting, host rock, mineral assemblages, REE geochemistry and fluid inclusion data are consistent with a submarine volcanic hydrothermal model for barite formation at the Chenarvardeh deposit. Mineral-forming fluids originated from solutions related to submarine hydrothermal activities deposited barite on seafloor as they encountered sulfate-bearing seawater.

Parasite distribution, prevalence, and assemblages of the grass shrimp, Palaemonetes pugio, in Southwestern Alabama, U.S.A.

USGS Publications Warehouse

Sheehan, Kate L.; Lafferty, Kevin D.; O'Brien, Jack; Cebrian, Just

2011-01-01

The grass shrimp, Palaemonetes pugio, harbors a number of symbionts within its North American range. Here, we document the distribution and seasonality of 4 taxonomic groups that use P. pugio as a host in coastal Alabama. We conducted a regional survey of 4 symbionts of P. pugio over 3 seasons and compared assemblages across space and time. The most common parasite was the metacercarial stage of the microphallid trematode Microphallus turgidus, which remained consistently prevalent over the 3 seasons surveyed. We also monitored the prevalence of M. turgidus at 2 sites monthly. Prevalence fluctuated significantly among seasons at these sites, but spatial heterogeneity appears to have a stronger influence on regional parasite prevalence. Distributions of 3 of 4 symbionts overlapped in a single geographic area (Mon Louis Island, Alabama, U.S.A.); however, multispecies infections of individual hosts were normally distributed within host populations. Sites surrounding Mon Louis Island had substantially higher parasite prevalence, particularly in the summer months. This area had a high quantity of Spartina marsh habitat, which we found influenced parasite prevalence, suggesting a role for wetland habitat in structuring parasite communities for this host.

Effects of long non-coding RNA HOST2 on cell migration and invasion by regulating MicroRNA let-7b in breast cancer.

PubMed

Lu, Peng-Wei; Li, Lin; Wang, Fang; Gu, Yuan-Ting

2018-06-01

The study intends to investigate the effects of long non-coding RNA HOST2 (lncRNA HOST2) on cell migration and invasion by regulating microRNA let-7b (let-7b) in breast cancer. Breast cancer and adjacent normal tissues were collected from 98 patients with breast cancer. Breast cancer MCF-7 cells were divided into the blank, negative control (NC), pcDNA3-Mock, siHOST2, let-7b inhibitor, pcDNA3-HOST2, let-7b mimic, pcDNA3-HOST2 + let-7b mimic, and siHOST2 + let-7b inhibitor groups. RT-qPCR was used to detect the mRNA expressions of HOST2, let-7b, and c-Myc. Western blotting was conducted to measure the c-Myc expression. Scratch test and Transwell assay were applied to detect the cell motility, migration, and invasion. Xenograft tumor in nude mice was performed to evaluate the effect of different transfection on the tumor growth. Compared with adjacent normal tissues, HOST2 expression was higher but let-7b expression lower in breast cancer tissues. HOST2 expression in breast cancer cells was remarkably increased compared with that in the normal breast epithelial MCF-10A cells. In MCF-7 cells, in comparison with the blank and NC groups, expressions of HOST2 and c-Myc were reduced, but let-7b expression was remarkably elevated in the siHOST2 and let-7b mimic groups; the let-7b inhibitor group exhibited higher expressions of HOST2 and c-Myc but lower let-7b expression. Overexpression of HOST2 could promote cell motility, migration and invasion, thus enhancing the growth of breast cancer tumor. By inhibiting HOST2, opposite trends were found. LncRNA HOST2 promotes cell migration and invasion by inhibiting let-7b in breast cancer patients. © 2017 Wiley Periodicals, Inc.

Host-seeking strategies of mosquito disease vectors.

PubMed

Day, Jonathan F

2005-12-01

Disease transmission by arthropods normally requires at least 2 host contacts. During the first, a pathogen (nematode, protozoan, or virus) is acquired along with the blood from an infected vertebrate host. The pathogen penetrates the vector's midgut and infects a variety of tissues, where replication may occur during an extrinsic incubation period lasting 3-30, days depending on vector and parasite physiology and ambient temperature. Following salivary-gland infection, the pathogen is usually transmitted to additional susceptible vertebrate hosts during future probing or blood feeding. The host-seeking strategies used by arthropod vectors can, in part, affect the efficiency of disease transmission. Vector abundance, seasonal distribution, habitat and host preference, and susceptibility to infection are all important components of disease-transmission cycles. Examples of 3 mosquito vectors of human disease are presented here to highlight the diversity of host seeking and to show how specific behaviors may influence disease-transmission cycles. In the African tropics, Anopheles gambiae s.s. is an efficient vector of human malaria due to its remarkably focused preference for human blood. Aedes aegypti is the main vector of dengue viruses in the New and Old World tropics and subtropics. This mosquito has evolved a domestic lifestyle and shares human habitations throughout much of its range. It prospers in settings where humans are its main source of blood. In south Florida, Culex nigripalpus is the major vector of St. Louis encephalitis (SLE) and West Nile (WN) viruses. This mosquito is opportunistic and blood feeds on virtually any available vertebrate host. It serves as an arboviral vector, in part, due to its ability to produce large populations in a short period of time. These 3 host-seeking and blood-feeding strategies make the specialist, as well as the opportunist, equally dangerous disease vectors.

The connection between globular cluster systems and their host galaxy and environment: a case study of the isolated elliptical NGC 821

NASA Astrophysics Data System (ADS)

Spitler, Lee R.; Forbes, Duncan A.; Strader, Jay; Brodie, Jean P.; Gallagher, Jay S.

2008-03-01

In an effort to probe the globular cluster (GC) system of an isolated elliptical galaxy, a comprehensive analysis of the NGC 821 GC system was performed. New imaging from the WIYN Mini-Mosaic imager, supplemented with Hubble Space Telescope (HST) WFPC2 images reveals a GC system similar to those found in counterpart ellipticals located in high-density environments. To put these results into the context of galaxy formation, a robustly determined census of GC systems is presented and analysed for galaxies spanning a wide range of masses (> M*), morphologies and environments. Results from this meta-study: (1) confirm previous findings that the number of GCs normalized by host galaxy stellar mass increases with host stellar mass. Spiral galaxies in the sample show smaller relative GC numbers than those of massive ellipticals, suggesting the GC systems of massive ellipticals were not formed from major spiral-spiral mergers; (2) indicate that GC system numbers per unit galaxy baryon mass increases with host baryon mass and that GC formation efficiency may not be universal as previously thought; (3) suggest previously reported trends with environment may be incorrect due to sample bias or the use of galaxy stellar masses to normalize GC numbers. Thus claims for environmentally dependent GC formation efficiencies should be revisited; (4) in combination with weak-lensing halo mass estimates, suggest that GCs formed in direct proportion to the halo mass; (5) are consistent with theoretical predictions whereby the local epoch of reionization did not vary significantly with environment or host galaxy type. Based upon data from the WIYN Observatory, which is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University and the National Optical Astronomy Observatories. Also includes analysis of observations made with the Hubble Space Telescope obtained from the ESO/ST-ECF Science Archive Facility. E-mail: lspitler@astro.swin.edu.au

Novel approach for identification of influenza virus host range and zoonotic transmissible sequences by determination of host-related associative positions in viral genome segments.

PubMed

Kargarfard, Fatemeh; Sami, Ashkan; Mohammadi-Dehcheshmeh, Manijeh; Ebrahimie, Esmaeil

2016-11-16

Recent (2013 and 2009) zoonotic transmission of avian or porcine influenza to humans highlights an increase in host range by evading species barriers. Gene reassortment or antigenic shift between viruses from two or more hosts can generate a new life-threatening virus when the new shuffled virus is no longer recognized by antibodies existing within human populations. There is no large scale study to help understand the underlying mechanisms of host transmission. Furthermore, there is no clear understanding of how different segments of the influenza genome contribute in the final determination of host range. To obtain insight into the rules underpinning host range determination, various supervised machine learning algorithms were employed to mine reassortment changes in different viral segments in a range of hosts. Our multi-host dataset contained whole segments of 674 influenza strains organized into three host categories: avian, human, and swine. Some of the sequences were assigned to multiple hosts. In point of fact, the datasets are a form of multi-labeled dataset and we utilized a multi-label learning method to identify discriminative sequence sites. Then algorithms such as CBA, Ripper, and decision tree were applied to extract informative and descriptive association rules for each viral protein segment. We found informative rules in all segments that are common within the same host class but varied between different hosts. For example, for infection of an avian host, HA14V and NS1230S were the most important discriminative and combinatorial positions. Host range identification is facilitated by high support combined rules in this study. Our major goal was to detect discriminative genomic positions that were able to identify multi host viruses, because such viruses are likely to cause pandemic or disastrous epidemics.

Sympatric diversification vs. immigration: deciphering host-plant specialization in a polyphagous insect, the stolbur phytoplasma vector Hyalesthes obsoletus (Cixiidae).

PubMed

Imo, Miriam; Maixner, Michael; Johannesen, Jes

2013-04-01

The epidemiology of vector transmitted plant diseases is highly influenced by dispersal and the host-plant range of the vector. Widening the vector's host range may increase transmission potential, whereas specialization may induce specific disease cycles. The process leading to a vector's host shift and its epidemiological outcome is therefore embedded in the frameworks of sympatric evolution vs. immigration of preadapted populations. In this study, we analyse whether a host shift of the stolbur phytoplasma vector, Hyalesthes obsoletus from field bindweed to stinging nettle in its northern distribution range evolved sympatrically or by immigration. The exploitation of stinging nettle has led to outbreaks of the grapevine disease bois noir caused by a stinging nettle-specific phytoplasma strain. Microsatellite data from populations from northern and ancestral ranges provide strong evidence for sympatric host-race evolution in the northern range: Host-plant associated populations were significantly differentiated among syntopic sites (0.054 < F(HT) < 0.098) and constant over 5 years. While gene flow was asymmetric from the old into the predicted new host race, which had significantly reduced genetic diversity, the genetic identity between syntopic host-race populations in the northern range was higher than between these populations and syntopic populations in ancestral ranges, where there was no evidence for genetic host races. Although immigration was detected in the northern field bindweed population, it cannot explain host-race diversification but suggests the introduction of a stinging nettle-specific phytoplasma strain by plant-unspecific vectors. The evolution of host races in the northern range has led to specific vector-based bois noir disease cycles. © 2013 Blackwell Publishing Ltd.

Host range, host specificity and hypothesized host shift events among viruses of lower vertebrates

PubMed Central

2011-01-01

The successful replication of a viral agent in a host is a complex process that often leads to a species specificity of the virus and can make interspecies transmission difficult. Despite this difficulty, natural host switch seems to have been frequent among viruses of lower vertebrates, especially fish viruses, since there are several viruses known to be able to infect a wide range of species. In the present review we will focus on well documented reports of broad host range, variations in host specificity, and host shift events hypothesized for viruses within the genera Ranavirus, Novirhabdovirus, Betanodavirus, Isavirus, and some herpesvirus. PMID:21592358

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

PubMed

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.

Western Spruce Budworm Consumption-Effects of Host Species and Foliage Chemistry

Treesearch

Michael R. Wagner; Elizabeth A.  Blake

1983-01-01

Feeding efficiencies and growth rates of western spruce budworm larvae varied among hosts tested. Pupae attained normal size regardless of host species. Candidate defensive compounds (tannins and phenols) varied only slightly with the vigor of the host. The relationship between these defensive compounds and measures of larvae growth were not entirely consistent with...

Do-or-die life cycles and diverse post-infection resistance mechanisms limit the evolution of parasite host ranges.

PubMed

Sieber, Michael; Gudelj, Ivana

2014-04-01

In light of the dynamic nature of parasite host ranges and documented potential for rapid host shifts, the observed high host specificity of most parasites remains an ecological paradox. Different variants of host-use trade-offs have become a mainstay of theoretical explanations of the prevalence of host specialism, but empirical evidence for such trade-offs is rare. We propose an alternative theory based on basic features of the parasite life cycle: host selection and subsequent intrahost replication. We introduce a new concept of effective burst size that accounts for the fact that successful host selection does not guarantee intrahost replication. Our theory makes a general prediction that a parasite will expand its host range if its effective burst size is positive. An in silico model of bacteria-phage coevolution verifies our predictions and demonstrates that the tendency for relatively narrow host ranges in parasites can be explained even in the absence of trade-offs. © 2014 John Wiley & Sons Ltd/CNRS.

Extending the Host Range of Bacteriophage Particles for DNA Transduction.

PubMed

Yosef, Ido; Goren, Moran G; Globus, Rea; Molshanski-Mor, Shahar; Qimron, Udi

2017-06-01

A major limitation in using bacteriophage-based applications is their narrow host range. Approaches for extending the host range have focused primarily on lytic phages in hosts supporting their propagation rather than approaches for extending the ability of DNA transduction into phage-restrictive hosts. To extend the host range of T7 phage for DNA transduction, we have designed hybrid particles displaying various phage tail/tail fiber proteins. These modular particles were programmed to package and transduce DNA into hosts that restrict T7 phage propagation. We have also developed an innovative generalizable platform that considerably enhances DNA transfer into new hosts by artificially selecting tails that efficiently transduce DNA. In addition, we have demonstrated that the hybrid particles transduce desired DNA into desired hosts. This study thus critically extends and improves the ability of the particles to transduce DNA into novel phage-restrictive hosts, providing a platform for myriad applications that require this ability. Copyright © 2017 Elsevier Inc. All rights reserved.

Initiation of a Low-Angle Normal Fault Active Across the Upper Brittle-Plastic Transition, Chemehuevi Mountains, CA

NASA Astrophysics Data System (ADS)

LaForge, J.; John, B. E.; Grimes, C. B.; Stunitz, H.; Heilbronner, R.

2016-12-01

The Chemehuevi detachment fault system, part of the regionally developed Colorado River extensional corridor, hosts exceptional exposures of a denuded fault system related to Miocene extension. Here, we characterize the early history of extension associated with a small slip (1-2 km) low-angle normal fault, the Mohave Wash fault (MWF), initially active across the brittle-plastic transition. Strain localized in three principal ways across the 23-km down-dip exposure (T <150° to >400°C): a brittle fault zone, localized, disseminated quartz mylonites, and syntectonic dikes hosting mylonitic fabrics. Brittle deformation in these crystalline rocks was concentrated into a 10-62-m thick brittle fault zone hosting localized, unmineralized to chlorite-epidote-quartz mineralized zones of cataclasite series fault rocks ≤3 m thick and rare pseudotachylite. Mylonitic deformation played an increased role in deformation down dip (NE), with mylonites increasing in quantity and average thickness. At shallow structural levels, footwall mylonites are absent; at 9-18 km down dip, cm-scale quartz mylonites are common; ≥18 km down dip, meter-scale syntectonic intermediate-felsic dikes are mylonitic, are attenuated into parallelism with the MWF, and host well-developed L-S fabric; 23 km down dip, the footwall hosts meter-thick zones of disseminated mylonitic quartz of varying intensities. These mylonites host microstructures that record progressively higher deformation temperature down dip, with dislocation-creep in quartz indicative of T of 280-400°C to ≥500°C, and diffusion creep with grain boundary sliding in dikes suggestive of even higher T deformation. Dike emplacement in the system is syntectonic with MWF slip; mafic-intermediate composition dikes intruded damage zone fractures and cataclasites, and were in turn fractured; Pb/U zircon ages of intermediate-felsic dikes range from ca. 1.5 ± 1 Ma to 3.8 ± 1 Ma after the onset of regional extension, but predate rapid slip. Cross cutting relations and absolute dating suggest the early history of the MWF evolved in two distinct phases: 1) seismogenic rupture with contemporaneous localized footwall mylonitization, followed by 2) additional cataclasis, episodic localized and magmatism, mylonitization and fluid-flow.

Interactions between immunotoxicants and parasite stress: Implications for host health.

PubMed

Booton, Ross D; Yamaguchi, Ryo; Marshall, James A R; Childs, Dylan Z; Iwasa, Yoh

2018-05-14

Many organisms face a wide variety of biotic and abiotic stressors which reduce individual survival, interacting to further reduce fitness. Here we studied the effects of two such interacting stressors: immunotoxicant exposure and parasite infection. We model the dynamics of a within-host infection and the associated immune response of an individual. We consider both the indirect sub-lethal effects on immunosuppression and the direct effects on health and mortality of individuals exposed to toxicants. We demonstrate that sub-lethal exposure to toxicants can promote infection through the suppression of the immune system. This happens through the depletion of the immune response which causes rapid proliferation in parasite load. We predict that the within-host parasite density is maximised by an intermediate toxicant exposure, rather than continuing to increase with toxicant exposure. In addition, high toxicant exposure can alter cellular regulation and cause the breakdown of normal healthy tissue, from which we infer higher mortality risk of the host. We classify this breakdown into three phases of increasing toxicant stress, and demonstrate the range of conditions under which toxicant exposure causes failure at the within-host level. These phases are determined by the relationship between the immunity status, overall cellular health and the level of toxicant exposure. We discuss the implications of our model in the context of individual bee health. Our model provides an assessment of how pesticide stress and infection interact to cause the breakdown of the within-host dynamics of individual bees. Copyright © 2018 Elsevier Ltd. All rights reserved.

Lack of host specialization on winter annual grasses in the fungal seed bank pathogen Pyrenophora semeniperda

Treesearch

Julie Beckstead; Susan E. Meyer; Toby S. Ishizuka; Kelsey M. McEvoy; Craig E. Coleman

2016-01-01

Generalist plant pathogens may have wide host ranges, but many exhibit varying degrees of host specialization, with multiple pathogen races that have narrower host ranges. These races are often genetically distinct, with each race causing highest disease incidence on its host of origin. We examined host specialization in the seed pathogen Pyrenophora...

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

PubMed Central

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

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

PubMed

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.

A brain imaging repository of normal structural MRI across the life course: Brain Images of Normal Subjects (BRAINS).

PubMed

Job, Dominic E; Dickie, David Alexander; Rodriguez, David; Robson, Andrew; Danso, Sammy; Pernet, Cyril; Bastin, Mark E; Boardman, James P; Murray, Alison D; Ahearn, Trevor; Waiter, Gordon D; Staff, Roger T; Deary, Ian J; Shenkin, Susan D; Wardlaw, Joanna M

2017-01-01

The Brain Images of Normal Subjects (BRAINS) Imagebank (http://www.brainsimagebank.ac.uk) is an integrated repository project hosted by the University of Edinburgh and sponsored by the Scottish Imaging Network: A Platform for Scientific Excellence (SINAPSE) collaborators. BRAINS provide sharing and archiving of detailed normal human brain imaging and relevant phenotypic data already collected in studies of healthy volunteers across the life-course. It particularly focusses on the extremes of age (currently older age, and in future perinatal) where variability is largest, and which are under-represented in existing databanks. BRAINS is a living imagebank where new data will be added when available. Currently BRAINS contains data from 808 healthy volunteers, from 15 to 81years of age, from 7 projects in 3 centres. Additional completed and ongoing studies of normal individuals from 1st to 10th decades are in preparation and will be included as they become available. BRAINS holds several MRI structural sequences, including T1, T2, T2* and fluid attenuated inversion recovery (FLAIR), available in DICOM (http://dicom.nema.org/); in future Diffusion Tensor Imaging (DTI) will be added where available. Images are linked to a wide range of 'textual data', such as age, medical history, physiological measures (e.g. blood pressure), medication use, cognitive ability, and perinatal information for pre/post-natal subjects. The imagebank can be searched to include or exclude ranges of these variables to create better estimates of 'what is normal' at different ages. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Multicenter survey on the outcome of transplantation of hematopoietic cells in patients with the complete form of DiGeorge anomaly

PubMed Central

Sedlacek, Petr; Hönig, Manfred; Friedrich, Wilhelm; Champagne, Martin; Matsumoto, Tadashi; Fischer, Alain; Neven, Benedicte; Contet, Audrey; Bensoussan, Danielle; Bordigoni, Pierre; Loeb, David; Savage, William; Jabado, Nada; Bonilla, Francisco A.; Slatter, Mary A.; Davies, E. Graham; Gennery, Andrew R.

2010-01-01

Seventeen patients transplanted with hematopoietic cells to correct severe T lymphocyte immunodeficiency resulting from complete DiGeorge anomaly were identified worldwide, and retrospective data were obtained using a questionnaire-based survey. Patients were treated at a median age of 5 months (range, 2-53 months) between 1995 and 2006. Bone marrow was used in 11 procedures in 9 cases: 6 from matched unrelated donors, 4 from human leukocyte antigen (HLA)-identical siblings, and one haploidentical parent with T-cell depletion. Unmobilized peripheral blood was used in 8 cases: 5 from HLA-identical siblings, one from a matched unrelated donor, one from an HLA-identical parent, and one unrelated matched cord blood. Conditioning was used in 5 patients and graft-versus-host disease prophylaxis in 11 patients. Significant graft-versus-host disease occurred in 9 patients, becoming chronic in 3. Median length of follow-up was 13 months, with transplantation from HLA-matched sibling showing the best results. Median survival among deceased patients (10 patients) was 7 months after transplantation (range, 2-18 months). The overall survival rate was 41%, with a median follow-up of 5.8 years (range, 4-11.5 years). Among survivors, median CD3 and CD4 counts were 806 (range, 644-1224) and 348 (range, 225-782) cells/mm3, respectively, CD4+/CD45RA+ cells remained very low, whereas mitogen responses were normalized. PMID:20530285

The effects of host size and temperature on the emergence of Echinoparyphium recurvatum cercariae from Lymnaea peregra under natural light conditions.

PubMed

Morley, N J; Adam, M E; Lewis, J W

2010-09-01

The production of cercariae from their snail host is a fundamental component of transmission success in trematodes. The emergence of Echinoparyphium recurvatum (Trematoda: Echinostomatidae) cercariae from Lymnaea peregra was studied under natural sunlight conditions, using naturally infected snails of different sizes (10-17 mm) within a temperature range of 10-29 degrees C. There was a single photoperiodic circadian cycle of emergence with one peak, which correlated with the maximum diffuse sunlight irradiation. At 21 degrees C the daily number of emerging cercariae increased with increasing host snail size, but variations in cercarial emergence did occur between both individual snails and different days. There was only limited evidence of cyclic emergence patterns over a 3-week period, probably due to extensive snail mortality, particularly those in the larger size classes. Very few cercariae emerged in all snail size classes at the lowest temperature studied (10 degrees C), but at increasingly higher temperatures elevated numbers of cercariae emerged, reaching an optimum between 17 and 25 degrees C. Above this range emergence was reduced. At all temperatures more cercariae emerged from larger snails. Analysis of emergence using the Q10 value, a measure of physiological processes over temperature ranges, showed that between 10 and 21 degrees C (approximately 15 degrees C) Q10 values exceeded 100 for all snail size classes, indicating a substantially greater emergence than would be expected for normal physiological rates. From 14 to 25 degrees C (approximately 20 degrees C) cercarial emergence in most snail size classes showed little change in Q10, although in the smallest size class emergence was still substantially greater than the typical Q10 increase expected over this temperature range. At the highest range of 21-29 degrees C (approximately 25 degrees C), Q10 was much reduced. The importance of these results for cercarial emergence under global climate change is discussed.

Methods of expanding bacteriophage host-range and bacteriophage produced by the methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crown, Kevin K.; Santarpia, Joshua

A method of producing novel bacteriophages with expanded host-range and bacteriophages with expanded host ranges are disclosed. The method produces mutant phage strains which are infectious to a second host and can be more infectious to their natural host than in their natural state. The method includes repeatedly passaging a selected phage strain into bacterial cultures that contain varied ratios of its natural host bacterial strain with a bacterial strain that the phage of interest is unable to infect; the target-host. After each passage the resulting phage are purified and screened for activity against the target-host via double-overlay assays. Whenmore » mutant phages that are shown to infect the target-host are discovered, they are further propagated in culture that contains only the target-host to produce a stock of the resulting mutant phage.« less

Human Gastric Mucins Differently Regulate Helicobacter pylori Proliferation, Gene Expression and Interactions with Host Cells

PubMed Central

Skoog, Emma C.; Sjöling, Åsa; Navabi, Nazanin; Holgersson, Jan; Lundin, Samuel B.; Lindén, Sara K.

2012-01-01

Helicobacter pylori colonizes the mucus niche of the gastric mucosa and is a risk factor for gastritis, ulcers and cancer. The main components of the mucus layer are heavily glycosylated mucins, to which H. pylori can adhere. Mucin glycosylation differs between individuals and changes during disease. Here we have examined the H. pylori response to purified mucins from a range of tumor and normal human gastric tissue samples. Our results demonstrate that mucins from different individuals differ in how they modulate both proliferation and gene expression of H. pylori. The mucin effect on proliferation varied significantly between samples, and ranged from stimulatory to inhibitory, depending on the type of mucins and the ability of the mucins to bind to H. pylori. Tumor-derived mucins and mucins from the surface mucosa had potential to stimulate proliferation, while gland-derived mucins tended to inhibit proliferation and mucins from healthy uninfected individuals showed little effect. Artificial glycoconjugates containing H. pylori ligands also modulated H. pylori proliferation, albeit to a lesser degree than human mucins. Expression of genes important for the pathogenicity of H. pylori (babA, sabA, cagA, flaA and ureA) appeared co-regulated in response to mucins. The addition of mucins to co-cultures of H. pylori and gastric epithelial cells protected the viability of the cells and modulated the cytokine production in a manner that differed between individuals, was partially dependent of adhesion of H. pylori to the gastric cells, but also revealed that other mucin factors in addition to adhesion are important for H. pylori-induced host signaling. The combined data reveal host-specific effects on proliferation, gene expression and virulence of H. pylori due to the gastric mucin environment, demonstrating a dynamic interplay between the bacterium and its host. PMID:22563496

Borrelia burgdorferi CheY2 Is Dispensable for Chemotaxis or Motility but Crucial for the Infectious Life Cycle of the Spirochete.

PubMed

Xu, Hui; Sultan, Syed; Yerke, Aaron; Moon, Ki Hwan; Wooten, R Mark; Motaleb, M A

2017-01-01

The requirements for bacterial chemotaxis and motility range from dispensable to crucial for host colonization. Even though more than 50% of all sequenced prokaryotic genomes possess at least one chemotaxis signaling system, many of those genomes contain multiple copies of a chemotaxis gene. However, the functions of most of those additional genes are unknown. Most motile bacteria possess at least one CheY response regulator that is typically dedicated to the control of motility and which is usually essential for virulence. Borrelia burgdorferi appears to be notably different, in that it has three cheY genes, and our current studies on cheY2 suggests that it has varied effects on different aspects of the natural infection cycle. Mutants deficient in this protein exhibit normal motility and chemotaxis in vitro but show reduced virulence in mice. Specifically, the cheY2 mutants were severely attenuated in murine infection and dissemination to distant tissues after needle inoculation. Moreover, while ΔcheY2 spirochetes are able to survive normally in the Ixodes ticks, mice fed upon by the ΔcheY2-infected ticks did not develop a persistent infection in the murine host. Our data suggest that CheY2, despite resembling a typical response regulator, functions distinctively from most other chemotaxis CheY proteins. We propose that CheY2 serves as a regulator for a B. burgdorferi virulence determinant that is required for productive infection within vertebrate, but not tick, hosts. Copyright © 2016 American Society for Microbiology.

Borrelia burgdorferi CheY2 Is Dispensable for Chemotaxis or Motility but Crucial for the Infectious Life Cycle of the Spirochete

PubMed Central

Xu, Hui; Sultan, Syed; Yerke, Aaron; Moon, Ki Hwan; Wooten, R. Mark

2016-01-01

ABSTRACT The requirements for bacterial chemotaxis and motility range from dispensable to crucial for host colonization. Even though more than 50% of all sequenced prokaryotic genomes possess at least one chemotaxis signaling system, many of those genomes contain multiple copies of a chemotaxis gene. However, the functions of most of those additional genes are unknown. Most motile bacteria possess at least one CheY response regulator that is typically dedicated to the control of motility and which is usually essential for virulence. Borrelia burgdorferi appears to be notably different, in that it has three cheY genes, and our current studies on cheY2 suggests that it has varied effects on different aspects of the natural infection cycle. Mutants deficient in this protein exhibit normal motility and chemotaxis in vitro but show reduced virulence in mice. Specifically, the cheY2 mutants were severely attenuated in murine infection and dissemination to distant tissues after needle inoculation. Moreover, while ΔcheY2 spirochetes are able to survive normally in the Ixodes ticks, mice fed upon by the ΔcheY2-infected ticks did not develop a persistent infection in the murine host. Our data suggest that CheY2, despite resembling a typical response regulator, functions distinctively from most other chemotaxis CheY proteins. We propose that CheY2 serves as a regulator for a B. burgdorferi virulence determinant that is required for productive infection within vertebrate, but not tick, hosts. PMID:27799336

Investigating the diversity of supernovae type Iax: a MUSE and NOT spectroscopic study of their environments

NASA Astrophysics Data System (ADS)

Lyman, J. D.; Taddia, F.; Stritzinger, M. D.; Galbany, L.; Leloudas, G.; Anderson, J. P.; Eldridge, J. J.; James, P. A.; Krühler, T.; Levan, A. J.; Pignata, G.; Stanway, E. R.

2018-01-01

SN 2002cx-like Type Ia supernovae (also known as SNe Iax) represent one of the most numerous peculiar SN classes. They differ from normal SNe Ia by having fainter peak magnitudes, faster decline rates and lower photospheric velocities, displaying a wide diversity in these properties. We present both integral-field and long-slit visual-wavelength spectroscopy of the host galaxies and explosion sites of SNe Iax to provide constraints on their progenitor formation scenarios. The SN Iax explosion-site metallicity distribution is similar to that of core-collapse SNe and metal poor compared to either normal SNe Ia or SN 1991T-like events. Fainter members, speculated to form distinctly from brighter SN Iax, are found at a range of metallicities, extending to very metal poor environments. Although the SN Iax explosion-sites' ages and star formation rates are comparatively older and less intense than the distribution of star-forming regions across their host galaxies, we confirm the presence of young stellar populations (SPs) at explosion environments for most SNe Iax, expanded here to a larger sample. Ages of the young SPs (several × 107 to 108 yr) are consistent with predictions for young thermonuclear and electron-capture SN progenitors. The lack of extremely young SPs at the explosion sites disfavours very massive progenitors such as Wolf-Rayet explosions with significant fallback. We find weak ionized gas in the only SN Iax host without obvious signs of star formation. The source of the ionization remains ambiguous but appears unlikely to be mainly due to young, massive stars.

Coupled range dynamics of brood parasites and their hosts responding to climate and vegetation changes.

PubMed

Péron, Guillaume; Altwegg, Res; Jamie, Gabriel A; Spottiswoode, Claire N

2016-09-01

As populations shift their ranges in response to global change, local species assemblages can change, setting the stage for new ecological interactions, community equilibria and evolutionary responses. Here, we focus on the range dynamics of four avian brood parasite species and their hosts in southern Africa, in a context of bush encroachment (increase in woody vegetation density in places previously occupied by savanna-grassland mosaics) favouring some species at the expense of others. We first tested whether hosts and parasites constrained each other's ability to expand or maintain their ranges. Secondly, we investigated whether range shifts represented an opportunity for new host-parasite and parasite-parasite interactions. We used multispecies dynamic occupancy models with interactions, fitted to citizen science data, to estimate the contribution of interspecific interactions to range shifts and to quantify the change in species co-occurrence probability over a 25-year period. Parasites were able to track their hosts' range shifts. We detected no deleterious effect of the parasites' presence on either the local population viability of host species or the hosts' ability to colonize newly suitable areas. In the recently diversified indigobird radiation (Vidua spp.), following bush encroachment, the new assemblages presented more potential opportunities for speciation via host switch, but also more potential for hybridization between extant lineages, also via host switch. Multispecies dynamic occupancy models with interactions brought new insights into the feedbacks between range shifts, biotic interactions and local demography: brood parasitism had little detected impact on extinction or colonization processes, but inversely the latter processes affected biotic interactions via the modification of co-occurrence patterns. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Role of larval host plants in the climate-driven range expansion of the butterfly Polygonia c-album.

PubMed

Braschler, Brigitte; Hill, Jane K

2007-05-01

1. Some species have expanded their ranges during recent climate warming and the availability of breeding habitat and species' dispersal ability are two important factors determining expansions. The exploitation of a wide range of larval host plants should increase an herbivorous insect species' ability to track climate by increasing habitat availability. Therefore we investigated whether the performance of a species on different host plants changed towards its range boundary, and under warmer temperatures. 2. We studied the polyphagous butterfly Polygonia c-album, which is currently expanding its range in Britain and apparently has altered its host plant preference from Humulus lupulus to include other hosts (particularly Ulmus glabra and Urtica dioica). We investigated insect performance (development time, larval growth rate, adult size, survival) and adult flight morphology on these host plants under four rearing temperatures (18-28.5 degrees C) in populations from core and range margin sites. 3. In general, differences between core and margin populations were small compared with effects of rearing temperature and host plant. In terms of insect performance, host plants were generally ranked U. glabra > or = U. dioica > H. lupulus at all temperatures. Adult P. c-album can either enter diapause or develop directly and higher temperatures resulted in more directly developing adults, but lower survival rates (particularly on the original host H. lupulus) and smaller adult size. 4. Adult flight morphology of wild-caught individuals from range margin populations appeared to be related to increased dispersal potential relative to core populations. However, there was no difference in laboratory reared individuals, and conflicting results were obtained for different measures of flight morphology in relation to larval host plant and temperature effects, making conclusions about dispersal potential difficult. 5. Current range expansion of P. c-album is associated with the exploitation of more widespread host plants on which performance is improved. This study demonstrates how polyphagy may enhance the ability of species to track climate change. Our findings suggest that observed differences in climate-driven range shifts of generalist vs. specialist species may increase in the future and are likely to lead to greatly altered community composition.

Shifts in Host Range of a Promiscuous Plasmid through Parallel Evolution of its Replication Initiation Protein

PubMed Central

Sota, Masahiro; Yano, Hirokazu; Hughes, Julie; Daughdrill, Gary W.; Abdo, Zaid; Forney, Larry J.; Top, Eva M.

2011-01-01

The ability of bacterial plasmids to adapt to novel hosts and thereby shift their host range is key to their long-term persistence in bacterial communities. Promiscuous plasmids of the IncP-1 group can colonize a wide range of hosts, but it is not known if and how they can contract, shift or further expand their host range. To understand the evolutionary mechanisms of host range shifts of IncP-1 plasmids, an IncP-1β mini-replicon was experimentally evolved in four hosts wherein it was initially unstable. After 1000 generations in serial batch cultures under antibiotic selection for plasmid maintenance (kanamycin resistance), the stability of the mini-plasmid had dramatically improved in all coevolved hosts. However, only plasmids evolved in Shewanella oneidensis showed improved stability in the ancestor, indicating that adaptive mutations had occurred in the plasmid itself. Complete genome sequence analysis of nine independently evolved plasmids showed seven unique plasmid genotypes that had various kinds of single mutations at one locus, namely the N-terminal region of the replication initiation protein TrfA. Such parallel evolution indicates that this region was under strong selection. In five of the seven evolved plasmids these trfA mutations resulted in a significantly higher plasmid copy number. Evolved plasmids were found to be stable in four other naïve hosts, but could no longer replicate in Pseudomonas aeruginosa. This study demonstrates that plasmids can specialize to a novel host through trade-offs between improved stability in the new host and the ability to replicate in a previously permissive host. PMID:20520653

Reconstituted normal human breast in nude mice: effect of host pregnancy environment and human chorionic gonadotropin on proliferation.

PubMed

Popnikolov, N; Yang, J; Liu, A; Guzman, R; Nandi, S

2001-03-01

The proliferation of normal human breast epithelial cells in women is highest during the first trimester of pregnancy. In an attempt to analyze this hormonal environment in a model system, the effect of host mouse pregnancy and the administration of human chorionic gonadotropin (hCG) were assessed in normal human breast epithelial cells transplanted into athymic nude mice. Human breast epithelial cells, dissociated from reduction mammoplasty specimens and embedded inside the extracellular matrices comprised of collagen gel and Matrigel, were transplanted into nude mice. Proliferation was measured in vivo by BrdU labeling followed by immunostaining of sections from recovered gels in response to an altered hormonal environment of the host animal. The host animal was mated to undergo pregnancy and the complex hormonal environment of the host animal pregnancy stimulated growth of transplanted human cells. This effect increased with progression of pregnancy and reached the maximum during late pregnancy prior to parturition. In order to determine whether additional stimulation could be achieved, the transplanted human cells were exposed to a second cycle of host mouse pregnancy by immediately mating the animal after parturition. This additional exposure of host mouse pregnancy did not result in further increase of proliferation. The effect of hCG administration on transplanted human cells was also tested, since hCG level is highest during the first trimester of human pregnancy and coincides with the maximal breast cell proliferation. Administration of hCG alone stimulated proliferation of human cells in a dose-dependent manner, and could further enhance stimulation achieved with estrogen. The host mouse mammary gland also responded to hCG treatment resulting in increased branching and lobulo-alveolar development. However, the hCG effect on both human and mouse cells was dependent on intact ovary since the stimulation did not occur in ovariectomized animals. Although hCG receptor transcripts were detected in human breast epithelial cells, raising the possibility of a direct mitogenic action, the hCG effect observed in this study may have been mediated via the ovary by increased secretion of ovarian steroids. In summary, using our in vivo nude mice system, the proliferation of normal human breast epithelial cells could be stimulated by host mouse pregnancy and by administration of hCG.

Population Dynamics of a Salmonella Lytic Phage and Its Host: Implications of the Host Bacterial Growth Rate in Modelling

PubMed Central

Santos, Sílvio B.; Carvalho, Carla; Azeredo, Joana; Ferreira, Eugénio C.

2014-01-01

The prevalence and impact of bacteriophages in the ecology of bacterial communities coupled with their ability to control pathogens turn essential to understand and predict the dynamics between phage and bacteria populations. To achieve this knowledge it is essential to develop mathematical models able to explain and simulate the population dynamics of phage and bacteria. We have developed an unstructured mathematical model using delay-differential equations to predict the interactions between a broad-host-range Salmonella phage and its pathogenic host. The model takes into consideration the main biological parameters that rule phage-bacteria interactions likewise the adsorption rate, latent period, burst size, bacterial growth rate, and substrate uptake rate, among others. The experimental validation of the model was performed with data from phage-interaction studies in a 5 L bioreactor. The key and innovative aspect of the model was the introduction of variations in the latent period and adsorption rate values that are considered as constants in previous developed models. By modelling the latent period as a normal distribution of values and the adsorption rate as a function of the bacterial growth rate it was possible to accurately predict the behaviour of the phage-bacteria population. The model was shown to predict simulated data with a good agreement with the experimental observations and explains how a lytic phage and its host bacteria are able to coexist. PMID:25051248

Host range of Caloptilia triadicae (Lepidoptera: Gracillariidae): an adventive herbivore of Chinese tallowtree (Malpighiales: Euphorbiaceae)

USDA-ARS?s Scientific Manuscript database

In its native range the invasive weed, Rhodomyrtus tomentosa is host to a suite of herbivores. One, Strepsicrates sp. (Lepidoptera: Tortricidae) was collected in China in 2014, introduced under quarantine in Florida, USA and tested against related species to determine its host range and suitability ...

Tools, Techniques, and Applications: Normalizing the VR Paradigm

NASA Technical Reports Server (NTRS)

Duncan, Gaeme

2008-01-01

Oshynee's precision Learning Objective performance factor rubrics with associated behavioral anchors integrates with Thinking Worlds(TradeMark), to provide event data recording and dynamic prescriptive feedback. Thinking Worlds(TradeMark) provides SCORM parametric data for reporting within the game and within overarching curricula or workplace evaluation strategy. - Open-sourced, browser-based digital dashboard reporting tools collect data from TW, LMS, LCMS, HR, and workplace metrics or control systems The games may be delivered across the internet or in a range of networked and stand-alone methods using the delivery model (s) required by the host organization.

Host density drives the postglacial migration of the tree parasite, Epifagus virginiana.

PubMed

Tsai, Yi-Hsin Erica; Manos, Paul S

2010-09-28

To survive changes in climate, successful species shift their geographic ranges to remain in suitable habitats. For parasites and other highly specialized species, distributional changes not only are dictated by climate but can also be engineered by their hosts. The extent of host control on parasite range expansion is revealed through comparisons of host and parasite migration and demographic histories. However, understanding the codistributional history of entire forest communities is complicated by challenges in synthesizing datasets from multiple interacting species of differing datatypes. Here we integrate genetic and fossil pollen datasets from a host-parasite pair; specifically, the population structure of the parasitic plant (Epifagus virginiana) was compared with both its host (Fagus grandifolia) genetic patterns and abundance data from the paleopollen record of the last 21,000 y. Through tests of phylogeographic structure and spatial linear regression models we find, surprisingly, host range changes had little effect on the parasite's range expansion and instead host density is the main driver of parasite spread. Unlike other symbionts that have been used as proxies to track their host's movements, this parasite's migration routes are incongruent with the host and instead reflect the greater importance of host density in this community's assembly. Furthermore, these results confirm predictions of disease ecological models regarding the role of host density in the spread of pathogens. Due to host density constraints, highly specialized species may have low migration capacities and long lag times before colonization of new areas.

Codon optimization underpins generalist parasitism in fungi

PubMed Central

Badet, Thomas; Peyraud, Remi; Mbengue, Malick; Navaud, Olivier; Derbyshire, Mark; Oliver, Richard P; Barbacci, Adelin; Raffaele, Sylvain

2017-01-01

The range of hosts that parasites can infect is a key determinant of the emergence and spread of disease. Yet, the impact of host range variation on the evolution of parasite genomes remains unknown. Here, we show that codon optimization underlies genome adaptation in broad host range parasites. We found that the longer proteins encoded by broad host range fungi likely increase natural selection on codon optimization in these species. Accordingly, codon optimization correlates with host range across the fungal kingdom. At the species level, biased patterns of synonymous substitutions underpin increased codon optimization in a generalist but not a specialist fungal pathogen. Virulence genes were consistently enriched in highly codon-optimized genes of generalist but not specialist species. We conclude that codon optimization is related to the capacity of parasites to colonize multiple hosts. Our results link genome evolution and translational regulation to the long-term persistence of generalist parasitism. DOI: http://dx.doi.org/10.7554/eLife.22472.001 PMID:28157073

Gene Expression Profiling of Monkeypox Virus-Infected Cells Reveals Novel Interfaces for Host-Virus Interactions

DTIC Science & Technology

2010-07-28

expression is plotted on Y -axis after normalization to mock-treated samples. Results plotted to compare calculated fold change in expression of each gene ...RESEARCH Open Access Gene expression profiling of monkeypox virus-infected cells reveals novel interfaces for host-virus interactions Abdulnaser...suppress antiviral cell defenses, exploit host cell machinery, and delay infection-induced cell death. However, a comprehensive study of all host genes

Perturbation of host-cell membrane is a primary mechanism of HIV cytopathology.

PubMed

Cloyd, M W; Lynn, W S

1991-04-01

Cytopathic viruses injure cells by a number of different mechanisms. The mechanism by which HIV-1 injures T cells was studied by temporally examining host-cell macromolecular syntheses, stages of the cell cycle, and membrane permeability following acute infection. T cells cytopathically infected at an m.o.i. of 1-5 grew normally for 24-72 hr, depending on the cell line, followed by the first manifestation of cell injury, slowing of cell division. At that time significant amounts of unintegrated HIV DNA and p24 core protein became detectable, and acridine orange flow cytometric cell cycle studies demonstrated the presence of fewer cells in the G2/M stage of the cell cycle. There was no change in the frequency of cells in the S-stage, and metabolic pulsing with radioactive precursors demonstrated that host-cell DNA, RNA, and protein syntheses were normal at that time and normal up to the time cells started to die (approximately 24 hr later), when all three decreased. Cellular lipid synthesis, however, was perturbed when cell multiplication slowed, with phospholipid synthesis reduced and neutral lipid synthesis enhanced. Permeability of the host-cell membrane to small molecules, such as Ca2+ and sucrose, was slightly enhanced early postinfection, and by the time of slowing of cell division, host membrane permeability was greatly increased to both Ca2+ and sucrose (Stokes radius 5.2 A) but not to inulin (Stokes radium 20 A). These changes in host-cell membrane permeability and phospholipid synthesis were not observed in acutely infected H9 cells, which are not susceptible to HIV cytopathology. Thus, HIV-1 appeared to predominantly injure T cells by perturbing host-cell membrane permeability and lipid synthesis, which is similar to the cytopathic mechanisms of paramyxoviruses.

Star Formation in the Central Regions of Galaxies

NASA Astrophysics Data System (ADS)

Tsai, Mengchun

2015-08-01

The galactic central region connects the galactic nucleus to the host galaxy. If the central black hole co-evolved with the host galaxies, there should be some evidence left in the central region. We use the environmental properties in the central regions such as star-forming activity, stellar population and molecular abundance to figure out a possible scenario of the evolution of galaxies. In this thesis at first we investigated the properties of the central regions in the host galaxies of active and normal galaxies. We used radio emission around the nuclei of the host galaxies to represent activity of active galactic nuclei (AGNs), and used infrared ray (IR) emission to represent the star-forming activity and stellar population of the host galaxies. We determined that active galaxies have higher stellar masses (SMs) within the central kiloparsec radius than normal galaxies do independent of the Hubble types of the host galaxies; but both active and normal galaxies exhibit similar specific star formation rates (SSFRs). We also discovered that certain AGNs exhibit substantial inner stellar structures in the IR images; most of the AGNs with inner structures are Seyferts, whereas only a few LINERs exhibit inner structures. We note that the AGNs with inner structures show a positive correlation between the radio activity of the AGNs and the SFRs of the host galaxies, but the sources without inner structures show a negative correlation between the radio power and the SFRs. These results might be explained with a scenario of starburst-AGN evolution. In this scenario, AGN activities are triggered following a nuclear starburst; during the evolution, AGN activities are accompanied by SF activity in the inner regions of the host galaxies; at the final stage of the evolution, the AGNs might transform into LINERs, exhibiting weak SF activity in the central regions of the host galaxies. For further investigation about the inner structure, we choose the most nearby and luminous Seyfert galaxy with inner structure as an example. In this thesis, we present CO(3-2) interferometric observations of the central region of the Seyfert 2 galaxy NGC1068 using the Submillimeter Array, together with CO(1-0) data taken with the Owens Valley Radio Observatory Millimeter Array. Both the CO(3-2) and CO(1-0) emission lines are mainly distributed within ~5 arcsec of the nucleus and along the spiral arms, but the intensity distributions show differences; the CO(3-2) map peaks in the nucleus, while the CO(1-0) emission is mainly located along the spiral arms. The CO(3-2)/CO(1-0) ratio is about 3.1 in the nucleus, which is four times as large as the average line ratio in the spiral arms, suggesting that the molecular gas there must be affected by the radiation arising from the AGN. On the other hand, the line ratios in the spiral arms vary over a wide range from 0.24 to 2.34 with a average value around 0.75, which is similar to the line ratios of star-formation regions, indicating that the molecular gas is affected by star formation. Besides, we see a tight correlation between CO(3-2)/(1-0) ratios in the spiral arms and star formation rate surface densities derived from Spitzer 8 micron dust flux densities. We also compare the CO(3-2)/(1-0) ratio and the star formation rate at different positions within the spiral arms; both are found to decrease as the radius from the nucleus increases.

A taxonomic revision of small neotropical saurian Malarias allied to Plasmodium minasense.

PubMed

Telford, S R

1979-01-01

Saurian malaria species which produce schizonts smaller than normal erythrocyte nuclei, with 4-8 merozoietes and gametocytes equal to or smaller than erythrocyte nuclei in size, parasitizing hosts of the lizard families Scincidae, Iguanidae and Teiidae in the Neotropics are considered to be Plasmodium minasense Carini and Rudolph, 1912. Subspecific designations are given to distinctive populations parasitizing different host species: P. minasense minasense is recognized from the type host, Mabuya mabouya of Brasil; P. minasense carinii Leger and Mouzels, 1917 from Iguana iguana of coastal South America; P. minasense anolisi subsp. nov. from Anolis limifrons of Panama; P. minasense capitoi subsp. nov. from Anolis capito of Panama; P. minasense plicae subsp. nov. from Plica umbra of Guyana; P. minasense tegui subsp. nov. from Tupinambis teguixin of Venezuela; and P. minasense diminutivum Telford, 1973, new combination, from Ameiva ameiva of Panama. Plasmodium rhadinurum Thompson and Huff, 1944 is recognized as a distinct species at present on the basis of possessing schizonts of different shape, asexual stages with filamentous projections in most portions of its range, and larger gametocytes, as well as apparent sympatry with P. minasense carinii in some areas.

Comparison of genome degradation in Paratyphi A and Typhi, human-restricted serovars of Salmonella enterica that cause typhoid.

PubMed

McClelland, Michael; Sanderson, Kenneth E; Clifton, Sandra W; Latreille, Phil; Porwollik, Steffen; Sabo, Aniko; Meyer, Rekha; Bieri, Tamberlyn; Ozersky, Phil; McLellan, Michael; Harkins, C Richard; Wang, Chunyan; Nguyen, Christine; Berghoff, Amy; Elliott, Glendoria; Kohlberg, Sara; Strong, Cindy; Du, Feiyu; Carter, Jason; Kremizki, Colin; Layman, Dan; Leonard, Shawn; Sun, Hui; Fulton, Lucinda; Nash, William; Miner, Tracie; Minx, Patrick; Delehaunty, Kim; Fronick, Catrina; Magrini, Vincent; Nhan, Michael; Warren, Wesley; Florea, Liliana; Spieth, John; Wilson, Richard K

2004-12-01

Salmonella enterica serovars often have a broad host range, and some cause both gastrointestinal and systemic disease. But the serovars Paratyphi A and Typhi are restricted to humans and cause only systemic disease. It has been estimated that Typhi arose in the last few thousand years. The sequence and microarray analysis of the Paratyphi A genome indicates that it is similar to the Typhi genome but suggests that it has a more recent evolutionary origin. Both genomes have independently accumulated many pseudogenes among their approximately 4,400 protein coding sequences: 173 in Paratyphi A and approximately 210 in Typhi. The recent convergence of these two similar genomes on a similar phenotype is subtly reflected in their genotypes: only 30 genes are degraded in both serovars. Nevertheless, these 30 genes include three known to be important in gastroenteritis, which does not occur in these serovars, and four for Salmonella-translocated effectors, which are normally secreted into host cells to subvert host functions. Loss of function also occurs by mutation in different genes in the same pathway (e.g., in chemotaxis and in the production of fimbriae).

The potential for host switching via ecological fitting in the emerald ash borer-host plant system.

PubMed

Cipollini, Don; Peterson, Donnie L

2018-02-27

The traits used by phytophagous insects to find and utilize their ancestral hosts can lead to host range expansions, generally to closely related hosts that share visual and chemical features with ancestral hosts. Host range expansions often result from ecological fitting, which is the process whereby organisms colonize and persist in novel environments, use novel resources, or form novel associations with other species because of the suites of traits that they carry at the time they encounter the novel environment. Our objective in this review is to discuss the potential and constraints on host switching via ecological fitting in emerald ash borer, Agrilus planipennis, an ecologically and economically important invasive wood boring beetle. Once thought of as an ash (Fraxinus spp.) tree specialist, recent studies have revealed a broader potential host range than was expected for this insect. We discuss the demonstrated host-use capabilities of this beetle, as well as the potential for and barriers to the adoption of additional hosts by this beetle. We place our observations in the context of biochemical mechanisms that mediate the interaction of these beetles with their host plants and discuss whether evolutionary host shifts are a possible outcome of the interaction of this insect with novel hosts.

Evolutionary interpretations of mycobacteriophage biodiversity and host-range through the analysis of codon usage bias.

PubMed

Esposito, Lauren A; Gupta, Swati; Streiter, Fraida; Prasad, Ashley; Dennehy, John J

2016-10-01

In an genomics course sponsored by the Howard Hughes Medical Institute (HHMI), undergraduate students have isolated and sequenced the genomes of more than 1,150 mycobacteriophages, creating the largest database of sequenced bacteriophages able to infect a single host, Mycobacterium smegmatis , a soil bacterium. Genomic analysis indicates that these mycobacteriophages can be grouped into 26 clusters based on genetic similarity. These clusters span a continuum of genetic diversity, with extensive genomic mosaicism among phages in different clusters. However, little is known regarding the primary hosts of these mycobacteriophages in their natural habitats, nor of their broader host ranges. As such, it is possible that the primary host of many newly isolated mycobacteriophages is not M. smegmatis , but instead a range of closely related bacterial species. However, determining mycobacteriophage host range presents difficulties associated with mycobacterial cultivability, pathogenicity and growth. Another way to gain insight into mycobacteriophage host range and ecology is through bioinformatic analysis of their genomic sequences. To this end, we examined the correlations between the codon usage biases of 199 different mycobacteriophages and those of several fully sequenced mycobacterial species in order to gain insight into the natural host range of these mycobacteriophages. We find that UPGMA clustering tends to match, but not consistently, clustering by shared nucleotide sequence identify. In addition, analysis of GC content, tRNA usage and correlations between mycobacteriophage and mycobacterial codon usage bias suggests that the preferred host of many clustered mycobacteriophages is not M. smegmatis but other, as yet unknown, members of the mycobacteria complex or closely allied bacterial species.

Evolutionary interpretations of mycobacteriophage biodiversity and host-range through the analysis of codon usage bias

PubMed Central

Esposito, Lauren A.; Gupta, Swati; Streiter, Fraida; Prasad, Ashley

2016-01-01

In an genomics course sponsored by the Howard Hughes Medical Institute (HHMI), undergraduate students have isolated and sequenced the genomes of more than 1,150 mycobacteriophages, creating the largest database of sequenced bacteriophages able to infect a single host, Mycobacterium smegmatis, a soil bacterium. Genomic analysis indicates that these mycobacteriophages can be grouped into 26 clusters based on genetic similarity. These clusters span a continuum of genetic diversity, with extensive genomic mosaicism among phages in different clusters. However, little is known regarding the primary hosts of these mycobacteriophages in their natural habitats, nor of their broader host ranges. As such, it is possible that the primary host of many newly isolated mycobacteriophages is not M. smegmatis, but instead a range of closely related bacterial species. However, determining mycobacteriophage host range presents difficulties associated with mycobacterial cultivability, pathogenicity and growth. Another way to gain insight into mycobacteriophage host range and ecology is through bioinformatic analysis of their genomic sequences. To this end, we examined the correlations between the codon usage biases of 199 different mycobacteriophages and those of several fully sequenced mycobacterial species in order to gain insight into the natural host range of these mycobacteriophages. We find that UPGMA clustering tends to match, but not consistently, clustering by shared nucleotide sequence identify. In addition, analysis of GC content, tRNA usage and correlations between mycobacteriophage and mycobacterial codon usage bias suggests that the preferred host of many clustered mycobacteriophages is not M. smegmatis but other, as yet unknown, members of the mycobacteria complex or closely allied bacterial species. PMID:28348827

Genomic Variation, Host Range, and Infection Kinetics of Closely Related Cyanopodoviruses from New England Coastal Waters

NASA Astrophysics Data System (ADS)

Veglia, A. J.; Milford, C. R.; Marston, M.

2016-02-01

Viruses infecting marine Synechococcus are abundant in coastal marine environments and influence the community composition and abundance of their cyanobacterial hosts. In this study, we focused on the cyanopodoviruses which have smaller genomes and narrower host ranges relative to cyanomyoviruses. While previous studies have compared the genomes of diverse podoviruses, here we analyzed the genomic variation, host ranges, and infection kinetics of podoviruses within the same OTU. The genomes of fifty-five podoviral isolates from the coastal waters of New England were fully sequenced. Based on DNA polymerase gene sequences, these isolates fall into five discrete OTUs (termed RIP - Rhode Island Podovirus). Although all the isolates belonging to the same RIP have very similar DNA polymerase gene sequences (>98% sequence identity), differences in genome content, particularly in regions associated with tail fiber genes, were observed among isolates in the same RIP. Host range tests reveal variation both across and within RIPs. Notably within RIP1, isolates that had similar tail fiber regions also had similar host ranges. Isolates belonging to RIP4 do not contain the host-derived psbA photosynthesis gene, while isolates in the other four RIPs do possess a psbA gene. Nevertheless, infection kinetic experiments suggest that the latent period and burst size for RIP4 isolates are similar to RIP1 isolates. We are continuing to investigate the correlations among genome content, host range, and infection kinetics of isolates belonging to the same OTU. Our results to date suggest that there is substantial genomic variation within an OTU and that this variation likely influences cyanopodoviral - host interactions.

INTEGRATING PARASITES AND PATHOGENS INTO THE STUDY OF GEOGRAPHIC RANGE LIMITS.

PubMed

Bozick, Brooke A; Real, Leslie A

2015-12-01

The geographic distributions of all species are limited, and the determining factors that set these limits are of fundamental importance to the fields of ecology and evolutionary biology. Plant and animal ranges have been of primary concern, while those of parasites, which represent much of the Earth's biodiversity, have been neglected. Here, we review the determinants of the geographic ranges of parasites and pathogens, and explore how parasites provide novel systems with which to investigate the ecological and evolutionary processes governing host/parasite spatial distributions. Although there is significant overlap in the causative factors that determine range borders of parasites and free-living species, parasite distributions are additionally constrained by the geographic range and ecology of the host species' population, as well as by evolutionary factors that promote host-parasite coevolution. Recently, parasites have been used to infer population demographic and ecological information about their host organisms and we conclude that this strategy can be further exploited to understand geographic range limitations of both host and parasite populations.

Solitary haemangioma of the shaft of long bones: resection and reconstruction with autologous bone graft.

PubMed

Li, Zhaoxu; Tang, Jicun; Ye, Zhaoming

2013-04-01

Bone haemangiomas are uncommon lesions, occurring in the skull or spine. A solitary haemangioma in the diaphysis of a long bone is rare. We retrospectively investigated six patients who presented with a solitary haemangioma in a long bone diaphysis. After segmental bone resection, the bone defect was replaced by a bone autograft. Patients were reviewed clinically and with radiographs. The mean follow-up was 6 years (range : 1-20 years). At the time of latest follow-up, no patient had a recurrence. Postoperative complications were one wound necrosis and one superficial wound infection. Union of the gap filling graft with the host bone was achieved in all patients at an average of 4 months (range: 3-8 months). The average Musculoskeletal Tumor Society functional score was 77% (range: 53%-90%) of normal at 6 months postoperatively, and 97% (range: 95%-99%) at the last follow-up evaluation. Segmental resection for solitary haemangioma and reconstruction with autologous bone graft can be considered as a suitable treatment option.

Host-induced aneuploidy and phenotypic diversification in the Sudden Oak Death pathogen Phytophthora ramorum.

PubMed

Kasuga, Takao; Bui, Mai; Bernhardt, Elizabeth; Swiecki, Tedmund; Aram, Kamyar; Cano, Liliana M; Webber, Joan; Brasier, Clive; Press, Caroline; Grünwald, Niklaus J; Rizzo, David M; Garbelotto, Matteo

2016-05-20

Aneuploidy can result in significant phenotypic changes, which can sometimes be selectively advantageous. For example, aneuploidy confers resistance to antifungal drugs in human pathogenic fungi. Aneuploidy has also been observed in invasive fungal and oomycete plant pathogens in the field. Environments conducive to the generation of aneuploids, the underlying genetic mechanisms, and the contribution of aneuploidy to invasiveness are underexplored. We studied phenotypic diversification and associated genome changes in Phytophthora ramorum, a highly destructive oomycete pathogen with a wide host-range that causes Sudden Oak Death in western North America and Sudden Larch Death in the UK. Introduced populations of the pathogen are exclusively clonal. In California, oak (Quercus spp.) isolates obtained from trunk cankers frequently exhibit host-dependent, atypical phenotypes called non-wild type (nwt), apparently without any host-associated population differentiation. Based on a large survey of genotypes from different hosts, we previously hypothesized that the environment in oak cankers may be responsible for the observed phenotypic diversification in P. ramorum. We show that both normal wild type (wt) and nwt phenotypes were obtained when wt P. ramorum isolates from the foliar host California bay (Umbellularia californica) were re-isolated from cankers of artificially-inoculated canyon live oak (Q. chrysolepis). We also found comparable nwt phenotypes in P. ramorum isolates from a bark canker of Lawson cypress (Chamaecyparis lawsoniana) in the UK; previously nwt was not known to occur in this pathogen population. High-throughput sequencing-based analyses identified major genomic alterations including partial aneuploidy and copy-neutral loss of heterozygosity predominantly in nwt isolates. Chromosomal breakpoints were located at or near transposons. This work demonstrates that major genome alterations of a pathogen can be induced by its host species. This is an undocumented type of plant-microbe interaction, and its contribution to pathogen evolution is yet to be investigated, but one of the potential collateral effects of nwt phenotypes may be host survival.

R Factor-Controlled Restriction and Modification of Deoxyribonucleic Acid: Restriction Mutants

PubMed Central

Yoshimori, Robert; Roulland-Dussoix, Daisy; Boyer, Herbert W.

1972-01-01

Restriction mutants of two different R factor-controlled host specificities (RI and RII) were isolated. All of the restriction mutants examined had a normal modification phenotype. No complementation was observed between the RI and RII host specificities. It is concluded that for each host specificity no protein subunit is shared by the restriction endonuclease and modification methylase. PMID:4565538

Dynamic intervention: pathogen disarmament of mitochondrial-based immune surveillance.

PubMed

Holland, Robin L; Blanke, Steven R

2014-11-12

In this issue of Cell Host & Microbe, Suzuki et al. (2014) describe a Vibrio cholerae Type-III-secreted effector that targets mitochondrial dynamics to dampen host innate immune signaling. This suggests that mammalian hosts possess surveillance mechanisms to monitor pathogen-mediated alterations in the integrity of normal cellular processes and organelles. Copyright © 2014 Elsevier Inc. All rights reserved.

Complete life cycle of the canid tapeworm, Echinococcus multilocularis, in laboratory rodents.

PubMed

Kamiya, M; Sato, H

1990-12-01

Mongolian gerbils, Meriones unguiculatus, when treated at intervals of 2-6 days with prednisolone tertiary butyl acetate, sustained infection with adult Echinococcus multilocularis in the small intestine, with the tapeworm exhibiting normal strobilation and egg production as in the natural canid host. Host age is critical for the survival of the tapeworm in normal gerbils; parasites survive for only 2 days in 20-wk-old animals, 4 days in 4-wk-old animals, but at least 7 days in 3-wk-old animals. The host age dependence in parasite recovery between days 28-37 postinfection was not affected by treatment from around the day of infection. Starting the treatment before infection (on day -17 relative to infection) remarkably improved the tapeworm's survival within the intestine of older animals. Eggs produced in this rodent model system 28 days postinfection were infective to rodents such as Mongolian gerbils and gray red-backed voles, Clethrionomys rufocanus bedfordiae, by oral or intraperitoneal inoculation. The E. multilocularis/Mongolian gerbil system can replace the natural canid hosts as a new way to obtain infective eggs and to analyze host-parasite interactions. The development of an alternative definitive host for zoonotic tapeworms may accelerate experimentation in this field.

Host-pathogen interactions in a varying environment: temperature, behavioural fever and fitness.

PubMed Central

Elliot, Sam L; Blanford, Simon; Thomas, Matthew B

2002-01-01

We demonstrate how variable temperatures, mediated by host thermoregulation and behavioural fever, critically affect the interaction between a host (the desert locust, Schistocerca gregaria) and a pathogen (the fungus Metarhizium anisopliae var. acridum). By means of behavioural thermoregulation, infected locusts can raise their body temperatures to fever levels. The adaptive value of this behaviour was examined using three thermal regimes wherein maximum body temperatures achievable were: (i) below, or (ii) at normally preferred temperatures, or were (iii) unrestricted, allowing heightened fever temperatures. All infected locusts ultimately succumbed to disease, with median survival times of 8, 15 and 21 days post-infection, respectively. Crucially, only those locusts able to fever produced viable offspring. This represents, to our knowledge, the first demonstration of the adaptive value of behavioural fever following infection with a naturally occurring pathogen. By contrast, although normal host thermoregulation moderately reduced pathogen reproduction (by 35%), there was no additional negative effect of fever, resulting in an asymmetry in the fitness consequences of fever for the host and the pathogen. The dependency of the host-pathogen interaction upon external abiotic conditions has implications for how virulence and resistance are treated both theoretically and in the management of pests and diseases. PMID:12184830

Fulfillment of Koch’s postulates and partial host range of Septoria lepidii Desm., a fungal pathogen for potential biological control of hoary cress (Lepidium spp.)

USDA-ARS?s Scientific Manuscript database

We have fulfilled Koch’s postulates and conducted host range tests with Septoria lepidii Desm. on five geographical accessions of hoary cress. Host range results showed the fungus specific to Lepidium spp. and damaging to hoary cress. This fungus is potentially an important biological control agent ...

Development of an aggressive bark beetle on novel hosts: Implications for outbreaks in an invaded range

Treesearch

Derek W. Rosenberger; Robert C. Venette; Brian H. Aukema; Jörg Müller

2018-01-01

Some subcortical insects have devastating effects on native tree communities in new ranges, despite benign interactions with their historical hosts. Examples of how insects, aggressive in their native habitat might respond in novel host environs are less common. One aggressive tree-killing insect undergoing a dramatic range shift is the mountain pine beetle (...

Black Holes in Bulgeless Galaxies: An XMM-Newton Investigation of NGC 3367 AND NGC 4536

NASA Technical Reports Server (NTRS)

McAlpine, W.; Satyapal, S.; Gliozzi, M.; Cheung, C. C.; Sambruna, R. M.; Eracleous, Michael

2012-01-01

The vast majority of optically identified active galactic nuclei (AGNs) in the local Universe reside in host galaxies with prominent bulges, supporting the hypothesis that black hole formation and growth is fundamentally connected to the build-up of galaxy bulges. However, recent mid-infrared spectroscopic studies with Spitzer of a sample of optically "normal" late-type galaxies reveal remarkably the presence of high-ionization [NeV] lines in several sources, providing strong evidence for AGNs in these galaxies. We present follow-up X-ray observations recently obtained with XMM-Newton of two such sources, the late-type optically normal galaxies NGC 3367 and NGC 4536. Both sources are detected in our observations. Detailed spectral analysis reveals that for both galaxies, the 2-10 keV emission is dominated by a power law with an X-ray luminosity in the L(sub 2- 10 keV) approximates 10(exp 39) - 10(exp 40) ergs/s range, consistent with low luminosity AGNs. While there is a possibility that X-ray binaries account for some fraction of the observed X-ray luminosity, we argue that this fraction is negligible. These observations therefore add to the growing evidence that the fraction of late-type galaxies hosting AGNs is significantly underestimated using optical observations alone. A comparison of the midinfrared [NeV] luminosity and the X-ray luminosities suggests the presence of an additional highly absorbed X-ray source in both galaxies, and that the black hole masses are in the range of 10(exp 5) - 10(exp 7) solar M for NGC 3367 and 10(exp 4) - (exp 10) solar M for NGC 4536

Species of Angiostrongylus (Nematoda: Metastrongyloidea) in wildlife: A review

PubMed Central

Spratt, David M.

2015-01-01

Twenty-one species of Angiostrongylus plus Angiostrongylus sp. (Nematoda: Metastrongyloidea) are known currently in wildlife. These occur naturally in rodents, tupaiids, mephitids, mustelids, procyonids, felids, and canids, and aberrantly in a range of avian, marsupial and eutherian hosts including humans. Adults inhabit the pulmonary arteries and right atrium, ventricle and vena cava, bronchioles of the lung or arteries of the caecum and mesentery. All species pass first-stage larvae in the faeces of the host and all utilise slugs and/or aquatic or terrestrial snails as intermediate hosts. Gastropods are infected by ingestion or penetration of first-stage larvae; definitive hosts by ingestion of gastropods or gastropod slime. Transmission of at least one species may involve ingestion of paratenic hosts. Five developmental pathways are identified in these life cycles. Thirteen species, including Angiostrongylus sp., are known primarily from the original descriptions suggesting limited geographic distributions. The remaining species are widespread either globally or regionally, and are continuing to spread. Small experimental doses of infective larvae (ca. 20) given to normal or aberrant hosts are tolerated, although generally eliciting a granulomatous histopathological response; large doses (100–500 larvae) often result in clinical signs and/or death. Two species, A. cantonensis and A. costaricensis, are established zoonoses causing neurological and abdominal angiostrongliasis respectively. The zoonotic potential of A. mackerrasae, A. malaysiensis and A. siamensis particularly warrant investigation. Angiostrongylus cantonensis occurs in domestic animals, mammalian and avian wildlife and humans in the metropolitan areas of Brisbane and Sydney, Australia, where it has been suggested that tawny frogmouths and brushtail possums may serve as biosentinels. A major conservation issue is the devastating role A. cantonensis may play around zoos and fauna parks where captive rearing of endangered species programmes may exist and where Rattus spp. are invariably a problem. PMID:25853051

Host and ecology both play a role in shaping distribution of digenean parasites of New Zealand whelks (Gastropoda: Buccinidae: Cominella).

PubMed

Donald, Kirsten M; Spencer, Hamish G

2016-08-01

Digenean parasites infecting four Cominella whelk species (C. glandiformis, C. adspersa, C. maculosa and C. virgata), which inhabit New Zealand's intertidal zone, were analysed using molecular techniques. Mitochondrial 16S and cytochrome oxidase 1 (COI) and nuclear rDNA ITS1 sequences were used to infer phylogenetic relationships amongst digenea. Host species were parasitized by a diverse range of digenea (Platyhelminthes, Trematoda), representing seven families: Echinostomatidae, Opecoelidae, Microphallidae, Strigeidae and three, as yet, undetermined families A, B and C. Each parasite family infected between one and three host whelk species, and infection levels were typically low (average infection rates ranged from 1·4 to 3·6%). Host specificity ranged from highly species-specific amongst the echinostomes, which were only ever observed infecting C. glandiformis, to the more generalist opecoelids and strigeids, which were capable of infecting three out of four of the Cominella species analysed. Digeneans displayed a highly variable geographic range; for example, echinostomes had a large geographic range stretching the length of New Zealand, from Northland to Otago, whereas Family B parasites were restricted to fairly small areas of the North Island. Our results add to a growing body of research identifying wide ranges in both host specificity and geographic range amongst intertidal, multi-host parasite systems.

Ecological host-range of Lilioceris cheni (Coleoptera: Chrysomelidae), a biological control agent of Dioscorea bulbifera L.

USDA-ARS?s Scientific Manuscript database

Open-field host-specificity testing assesses the host-range of a biological control agent in a setting that permits the agent to use its full complement of host-seeking behaviors. This form of testing, particularly when it includes a no-choice phase in which the target weed is killed, may provide th...

Disease and the extended phenotype: parasites control host performance and survival through induced changes in body plan.

PubMed

Goodman, Brett A; Johnson, Pieter T J

2011-01-01

By definition, parasites harm their hosts. However, some forms of parasite-induced alterations increase parasite transmission between hosts, such that manipulated hosts can be considered extensions of the parasite's phenotype. While well accepted in principle, surprisingly few studies have quantified how parasite manipulations alter host performance and survival under field and laboratory conditions. By interfering with limb development, the trematode Ribeiroia ondatrae causes particularly severe morphological alterations within amphibian hosts that provide an ideal system to evaluate parasite-induced changes in phenotype. Here, we coupled laboratory performance trials with a capture-mark-recapture study of 1388 Pacific chorus frogs (Pseudacris regilla) to quantify the effects of parasite-induced malformations on host locomotion, foraging, and survival. Malformations, which affected ∼ 50% of metamorphosing frogs in nature, caused dramatic reductions in all measures of organismal function. Malformed frogs exhibited significantly shorter jumping distances (41% reduction), slower swimming speeds (37% reduction), reduced endurance (66% reduction), and lower foraging success relative to infected hosts without malformations. Furthermore, while normal and malformed individuals had comparable survival within predator-free exclosures, deformed frogs in natural populations had 22% lower biweekly survival than normal frogs and rarely recruited to the adult population over a two-year period. Our results highlight the ability of parasites to deeply alter multiple dimensions of host phenotype with important consequences for performance and survival. These patterns were best explained by malformation status, rather than infection per se, helping to decouple the direct and indirect effects of parasitism on host fitness.

Disease and the Extended Phenotype: Parasites Control Host Performance and Survival through Induced Changes in Body Plan

PubMed Central

Goodman, Brett A.; Johnson, Pieter T. J.

2011-01-01

Background By definition, parasites harm their hosts. However, some forms of parasite-induced alterations increase parasite transmission between hosts, such that manipulated hosts can be considered extensions of the parasite's phenotype. While well accepted in principle, surprisingly few studies have quantified how parasite manipulations alter host performance and survival under field and laboratory conditions. Methodology/Principal Findings By interfering with limb development, the trematode Ribeiroia ondatrae causes particularly severe morphological alterations within amphibian hosts that provide an ideal system to evaluate parasite-induced changes in phenotype. Here, we coupled laboratory performance trials with a capture-mark-recapture study of 1388 Pacific chorus frogs (Pseudacris regilla) to quantify the effects of parasite-induced malformations on host locomotion, foraging, and survival. Malformations, which affected ∼50% of metamorphosing frogs in nature, caused dramatic reductions in all measures of organismal function. Malformed frogs exhibited significantly shorter jumping distances (41% reduction), slower swimming speeds (37% reduction), reduced endurance (66% reduction), and lower foraging success relative to infected hosts without malformations. Furthermore, while normal and malformed individuals had comparable survival within predator-free exclosures, deformed frogs in natural populations had 22% lower biweekly survival than normal frogs and rarely recruited to the adult population over a two-year period. Conclusions/Significance Our results highlight the ability of parasites to deeply alter multiple dimensions of host phenotype with important consequences for performance and survival. These patterns were best explained by malformation status, rather than infection per se, helping to decouple the direct and indirect effects of parasitism on host fitness. PMID:21633498

Distributional Patterns of Pseudacteon Associated with the Solenopsis saevissima Complex in South America

PubMed Central

Patrock, Richard J. W.; Porter, Sanford D.; Gilbert, Lawrence E.; Folgarait, Patricia J.

2009-01-01

Classical biological control efforts against imported fire ants have largely involved the use of Pseudacteon parasitoids. To facilitate further exploration for species and population biotypes a database of collection records for Pseudacteon species was organized, including those from the literature and other sources. These data were then used to map the geographical ranges of species associated with the imported fire ants in their native range in South America. In addition, we found geographical range metrics for all species in the genus and related these metrics to latitude and host use. Approximately equal numbers of Pseudacteon species were found in temperate and tropical regions, though the majority of taxa found only in temperate areas were found in the Northern Hemisphere. No significant differences in sizes of geographical ranges were found between Pseudacteon associated with the different host complexes of fire ants despite the much larger and systemic collection effort associated with the S. saevissima host group. The geographical range of the flies was loosely associated with both the number of hosts and the geographical range of their hosts. Pseudacteon with the most extensive ranges had either multiple hosts or hosts with broad distributions. Mean species richnesses of Pseudacteon in locality species assemblages associated with S. saevissima complex ants was 2.8 species, but intensively sampled locations were usually much higher. Possible factors are discussed related to variation in the size of geographical range, and areas in southern South America are outlined that are likely to have been under-explored for Pseudacteon associated with imported fire ants. PMID:20050779

Development and Validation of a Microtiter Plate-Based Assay for Determination of Bacteriophage Host Range and Virulence.

PubMed

Xie, Yicheng; Wahab, Laith; Gill, Jason J

2018-04-12

Bacteriophages, which are the natural predators of bacteria, have re-emerged as an attractive alternative to combat antibiotic resistant bacteria. Phages are highly specific at the species and strain level and measurement of the phage host range plays an important role in utilizing the phage as antimicrobials. The most common method for phage host range determination has been to spot phage lysates on soft agar overlays and observe plaque formation. In this study, a liquid culture-based assay was developed in a 96-well microtiter plate format to measure the phage host range and virulence for a collection of 15 Salmonella phages against a panel of 20 Salmonella strains representing 11 serovars. This method was compared to a traditional spot method. The majority of the host range results from two methods were in agreement including in cases where a bacterial strain was insensitive to the phage. Each method produced a false-negative result in 19/300 (6%) of the measured phage-host combinations when compared to the other method. The spot method tended to indicate greater phage sensitivity than the microtiter assay even though direct comparisons of the response magnitude between the two methods is difficult since they operate on different mechanisms. The microtiter plate assay was able to provide data on both the phage host range and virulence in greater resolution in a high-throughput format.

Development and Validation of a Microtiter Plate-Based Assay for Determination of Bacteriophage Host Range and Virulence

PubMed Central

Xie, Yicheng; Wahab, Laith

2018-01-01

Bacteriophages, which are the natural predators of bacteria, have re-emerged as an attractive alternative to combat antibiotic resistant bacteria. Phages are highly specific at the species and strain level and measurement of the phage host range plays an important role in utilizing the phage as antimicrobials. The most common method for phage host range determination has been to spot phage lysates on soft agar overlays and observe plaque formation. In this study, a liquid culture-based assay was developed in a 96-well microtiter plate format to measure the phage host range and virulence for a collection of 15 Salmonella phages against a panel of 20 Salmonella strains representing 11 serovars. This method was compared to a traditional spot method. The majority of the host range results from two methods were in agreement including in cases where a bacterial strain was insensitive to the phage. Each method produced a false-negative result in 19/300 (6%) of the measured phage-host combinations when compared to the other method. The spot method tended to indicate greater phage sensitivity than the microtiter assay even though direct comparisons of the response magnitude between the two methods is difficult since they operate on different mechanisms. The microtiter plate assay was able to provide data on both the phage host range and virulence in greater resolution in a high-throughput format. PMID:29649135

STRUCTURAL CONTROLS OF THE EMERSON PASS GEOTHERMAL SYSTEM, NORTHWESTERN NEVADA: CHARACTERIZATION OF A "BLIND" SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Ryan B; Faulds, James E

Detailed geologic analyses have elucidated the kinematics, stress state, structural controls, and past surface activity of a blind geothermal system in Emerson Pass on the Pyramid Lake Paiute Reservation, western Nevada. The Emerson Pass area resides near the boundary of the Basin and Range and Walker Lane provinces and at the western edge of a broad left step or relay ramp between the north- to north-northeast-striking, west-dipping, Fox and Lake Range normal faults. The step-over provides a structurally favorable setting for deep circulation of meteoric fluids. Strata in the area are comprised of late Miocene to Pliocene sedimentary rocks andmore » the middle Miocene Pyramid sequence mafic to intermediate volcanic rocks, all overlying Mesozoic metasedimentary and intrusive rocks. A thermal anomaly was discovered in Emerson Pass by use of 2-m temperature surveys deployed within a structurally favorable setting and proximal to surface features indicative of geothermal activity. The 2-m temperature surveys define a north-south elongate thermal anomaly that has a maximum recorded temperature of ~60°C and resides on a north- to north-northeast-striking normal fault. Although the active geothermal system is expressed solely as a soil heat anomaly, late Pleistocene travertine and tufa mounds, chalcedonic silica/calcite veins, and silica cemented Pleistocene lacustrine gravels indicate a robust geothermal system was active at the surface in the recent past. The geothermal system is controlled primarily by the broad step-over between two major range-bounding normal faults. In detail, the system likely results from enhanced permeability generated by the intersection of two oppositely dipping, southward terminating north- to north-northwest-striking (Fox Range fault) and north-northeast-striking normal faults. Structural complexity and spatial heterogeneities of the strain and stress field have developed in the step-over region, but kinematic data suggest a west-northwest-trending (~280° azimuth) extension direction. Therefore, geothermal activity in the Emerson Pass area is probably hosted on north-to north-northeast striking normal faults.« less

Host selection and lethality of attacks by sea lampreys (Petromyzon marinus) in laboratory studies

USGS Publications Warehouse

Swink, William D.

2003-01-01

Parasitic-phase sea lampreys (Petromyzon marinus) are difficult to study in the wild. A series of laboratory studies (1984-1995) of single attacks on lake trout (Salvelinus namaycush), rainbow trout (Oncorhynchus mykiss), and burbot (Lota lota) examined host size selection; determined the effects of host size, host species, host strain, and temperature on host mortality; and estimated the weight of hosts killed per lamprey. Rainbow trout were more able and burbot less able to survive attacks than lake trout. Small sea lampreys actively selected the larger of two small hosts; larger sea lampreys attacked larger hosts in proportion to the hosts' body sizes, but actively avoided shorter hosts (a?? 600 mm) when larger were available. Host mortality was significantly less for larger (43-44%) than for smaller hosts (64%). However, the yearly loss of hosts per sea lamprey was less for small hosts (range, 6.8-14.2 kg per sea lamprey) than larger hosts (range, 11.4-19.3 kg per sea lamprey). Attacks at the lower of two temperature ranges (6.1-11.8A?C and 11.1-15.0A?C) did not significantly reduce the percentage of hosts killed (54% vs. 69%, p > 0.21), but longer attachment times at lower temperatures reduced the number of hosts attacked (33 vs. 45), and produced the lowest loss of hosts (6.6 kg per sea lamprey). Low temperature appeared to offset other factors that increase host mortality. Reanalysis of 789 attacks pooled from these studies, using forward stepwise logistic regression, also identified mean daily temperature as the dominant factor affecting host mortality. Observations in Lakes Superior, Huron, and Ontario support most laboratory results.

Large-scale maps of variable infection efficiencies in aquatic Bacteroidetes phage-host model systems: Variable phage-host infection interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmfeldt, Karin; Solonenko, Natalie; Howard-Varona, Cristina

Microbes drive ecosystem functioning and their viruses modulate these impacts through mortality, gene transfer and metabolic reprogramming. Despite the importance of virus-host interactions and likely variable infection efficiencies of individual phages across hosts, such variability is seldom quantified. In this paper, we quantify infection efficiencies of 38 phages against 19 host strains in aquatic Cellulophaga (Bacteroidetes) phage-host model systems. Binary data revealed that some phages infected only one strain while others infected 17, whereas quantitative data revealed that efficiency of infection could vary 10 orders of magnitude, even among phages within one population. This provides a baseline for understanding andmore » modeling intrapopulation host range variation. Genera specific host ranges were also informative. For example, the Cellulophaga Microviridae, showed a markedly broader intra-species host range than previously observed in Escherichia coli systems. Further, one phage genus, Cba41, was examined to investigate nonheritable changes in plating efficiency and burst size that depended on which host strain it most recently infected. While consistent with host modification of phage DNA, no differences in nucleotide sequence or DNA modifications were detected, leaving the observation repeatable, but the mechanism unresolved. Overall, this study highlights the importance of quantitatively considering replication variations in studies of phage-host interactions.« less

Large-scale maps of variable infection efficiencies in aquatic Bacteroidetes phage-host model systems: Variable phage-host infection interactions

DOE PAGES

Holmfeldt, Karin; Solonenko, Natalie; Howard-Varona, Cristina; ...

2016-06-28

Microbes drive ecosystem functioning and their viruses modulate these impacts through mortality, gene transfer and metabolic reprogramming. Despite the importance of virus-host interactions and likely variable infection efficiencies of individual phages across hosts, such variability is seldom quantified. In this paper, we quantify infection efficiencies of 38 phages against 19 host strains in aquatic Cellulophaga (Bacteroidetes) phage-host model systems. Binary data revealed that some phages infected only one strain while others infected 17, whereas quantitative data revealed that efficiency of infection could vary 10 orders of magnitude, even among phages within one population. This provides a baseline for understanding andmore » modeling intrapopulation host range variation. Genera specific host ranges were also informative. For example, the Cellulophaga Microviridae, showed a markedly broader intra-species host range than previously observed in Escherichia coli systems. Further, one phage genus, Cba41, was examined to investigate nonheritable changes in plating efficiency and burst size that depended on which host strain it most recently infected. While consistent with host modification of phage DNA, no differences in nucleotide sequence or DNA modifications were detected, leaving the observation repeatable, but the mechanism unresolved. Overall, this study highlights the importance of quantitatively considering replication variations in studies of phage-host interactions.« less

The Relation between Luminous AGNs and Star Formation in Their Host Galaxies

NASA Astrophysics Data System (ADS)

Xu, Lei; Rieke, G. H.; Egami, E.; Haines, C. P.; Pereira, M. J.; Smith, G. P.

2015-08-01

We study the relation of active galactic nuclei (AGNs) to star formation in their host galaxies. Our sample includes 205 Type-1 and 85 Type-2 AGNs, 162 detected with Herschel, from fields surrounding 30 galaxy clusters in the Local Cluster Substructure Survey. The sample is identified by optical line widths and ratios after selection to be brighter than 1 mJy at 24 μm. We show that Type-2 AGN [O iii]λ5007 line fluxes at high z can be contaminated by their host galaxies with typical spectrograph entrance apertures (but our sample is not compromised in this way). We use spectral energy distribution (SED) templates to decompose the galaxy SEDs and estimate star formation rates (SFRs), AGN luminosities, and host galaxy stellar masses (described in an accompanying paper). The AGNs arise from massive black holes (˜ 3× {10}8{M}⊙ ) accreting at ˜10% of the Eddington rate and residing in galaxies with stellar mass \\gt 3× {10}10{M}⊙ ; those detected with Herschel have IR luminosity from star formation in the range of {L}{SF,{IR}}˜ {10}10-{10}12{L}⊙ . We find that (1) the specific SFRs in the host galaxies are generally consistent with those of normal star-forming (main sequence) galaxies; (2) there is a strong correlation between the luminosities from star formation and the AGN; and (3) the correlation may not result from a causal connection, but could arise because the black hole mass (and hence AGN Eddington luminosity) and star formation are both correlated with the galaxy mass.

Solving the puzzle: What is behind our forefathers’ anti-inflammatory remedies?

PubMed Central

Rodríguez Villanueva, Javier; Martín Esteban, Jorge; Rodríguez Villanueva, Laura

2017-01-01

Inflammation is a ubiquitous host response in charge of restoring normal tissue structure and function but is a double-edged sword, as the uncontrolled or excessive process can lead to the injury of host cells, chronic inflammation, chronic diseases, and also neoplastic transformation. Throughout history, a wide range of species has been claimed to have anti-inflammatory effects worldwide. Among them, Angelica sinensis, Tropaeolum majus, Castilleja tenuiflora, Biophytum umbraculum, to name just a few, have attracted the scientific and general public attention in the last years. Efforts have been made to assess their relevance through a scientific method. However, inflammation is a complex interdependent process, and phytomedicines are complex mixtures of compounds with multiple mechanisms of biological actions, which restricts systematic explanation. For this purpose, the omics techniques could prove extremely useful. They provide tools for interpreting and integrating results from both the classical medical tradition and modern science. As a result, the concept of network pharmacology applied to phytomedicines emerged. All of this is a step toward personalized therapy. PMID:28163971

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

PubMed

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.

Tolerance to Vascularized Composite Allografts in Canine Mixed Hematopoietic Chimeras

PubMed Central

Mathes, David W.; Hwang, Billanna; Graves, Scott S.; Edwards, James; Chang, Jeff; Storer, Barry E.; Butts-Miwongtum, Tiffany; Sale, George E.; Nash, Richard A.; Storb, Rainer.

2012-01-01

Background Mixed donor-host chimerism, established through hematopoietic cell transplantation (HCT), is a highly reproducible strategy for the induction of tolerance towards solid organs. Here, we ask whether a nonmyeloablative conditioning regimen establishing mixed donor-host chimerism leads to tolerance of highly antigenic vascularized composite allografts. Methods Stable mixed chimerism was established in dogs given a sublethal dose (1–2 Gy) total body irradiation before and a short course of immunosuppression after dog leukocyte antigen-identical marrow transplantation. Vascularized composite allografts from marrow donors were performed after a median of 36 (range 4-54) months after HCT. Results All marrow recipients maintained mixed donor-host hematopoietic chimerism and accepted composite tissue grafts for periods ranging between 52 and 90 weeks; in turn, marrow donors rejected vascularized composite allografts from their respective marrow recipients within 18–29 days. Biopsies of muscle and skin of vascularized composite allografts from mixed chimeras showed few infiltrating cells compared to extensive infiltrates in biopsies of vascularized composite allografts from marrow donors. Elevated levels of CD3+ FoxP3+ T-regulatory cells were found in skin and muscle of vascularized composite allografts of mixed chimeras compared to normal tissues. In mixed chimeras, increased numbers of T-regulatory cells were found in draining compared to non-draining lymph nodes of vascularized composite allografts. Conclusion These data suggest that nonmyeloablative HCT may form the basis for future clinical applications of solid organ transplantation and that T-regulatory cells may function towards maintenance of the vascularized composite allograft. PMID:22082819

The MVMp P4 promoter is a host cell-type range determinant in vivo.

PubMed

Meir, Chen; Mincberg, Michal; Rostovsky, Irina; Tal, Saar; Vollmers, Ellen M; Levi, Adi; Tattersall, Peter; Davis, Claytus

2017-06-01

The protoparvovirus early promoters, e.g. P4 of Minute Virus of Mice (MVM), play a critical role during infection. Initial P4 activity depends on the host transcription machinery only. Since this is cell-type dependent, it is hypothesized that P4 is a host cell-type range determinant. Yet host range determinants have mapped mostly to capsid, never P4. Here we test the hypothesis using the mouse embryo as a model system. Disruption of the CRE element of P4 drastically decreased infection levels without altering range. However, when we swapped promoter elements of MVM P4 with those from equivalent regions of the closely related H1 virus, we observed elimination of infection in fibroblasts and chondrocytes and the acquisition of infection in skeletal muscle. We conclude that P4 is a host range determinant and a target for modifying the productive infection potential of the virus - an important consideration in adapting these viruses for oncotherapy. Copyright © 2017 Elsevier Inc. All rights reserved.

Transient dominant host-range selection using Chinese hamster ovary cells to generate marker-free recombinant viral vectors from vaccinia virus.

PubMed

Liu, Liang; Cooper, Tamara; Eldi, Preethi; Garcia-Valtanen, Pablo; Diener, Kerrilyn R; Howley, Paul M; Hayball, John D

2017-04-01

Recombinant vaccinia viruses (rVACVs) are promising antigen-delivery systems for vaccine development that are also useful as research tools. Two common methods for selection during construction of rVACV clones are (i) co-insertion of drug resistance or reporter protein genes, which requires the use of additional selection drugs or detection methods, and (ii) dominant host-range selection. The latter uses VACV variants rendered replication-incompetent in host cell lines by the deletion of host-range genes. Replicative ability is restored by co-insertion of the host-range genes, providing for dominant selection of the recombinant viruses. Here, we describe a new method for the construction of rVACVs using the cowpox CP77 protein and unmodified VACV as the starting material. Our selection system will expand the range of tools available for positive selection of rVACV during vector construction, and it is substantially more high-fidelity than approaches based on selection for drug resistance.

New records with examples of potential host colonization events for hypopi (Acari: Hypoderatidae) from birds

USGS Publications Warehouse

Pence, Danny B.; Spalding, M.G.; Bergan, J.F.; Cole, Rebecca A.

1997-01-01

New host, geographic records, or both are established for 14 species of hypoderatid deutonymphs from 14 species of birds in North America. Ten of these records are regarded as examples of a potential host colonization event where these hypopi have become established in hosts other than those with which they are normally associated. Herein, potential host colonization events by hypoderatid deutonymphs are regarded as more of an ecologically determined than physiologically specific phenomenon, often specifically related to sharing of nesting sites in the same rookeries by different host taxa. Neottialges ibisicola Young & Pence is placed as a junior synonym of Neottialges plegadicola Fain. The taxonomic status of Hypodectes propus from columbid versus ardeid hosts needs further study.

One Health and Food-Borne Disease: Salmonella Transmission between Humans, Animals, and Plants.

PubMed

Silva, Claudia; Calva, Edmundo; Maloy, Stanley

2014-02-01

There are >2,600 recognized serovars of Salmonella enterica. Many of these Salmonella serovars have a broad host range and can infect a wide variety of animals, including mammals, birds, reptiles, amphibians, fish, and insects. In addition, Salmonella can grow in plants and can survive in protozoa, soil, and water. Hence, broad-host-range Salmonella can be transmitted via feces from wild animals, farm animals, and pets or by consumption of a wide variety of common foods: poultry, beef, pork, eggs, milk, fruit, vegetables, spices, and nuts. Broad-host-range Salmonella pathogens typically cause gastroenteritis in humans. Some Salmonella serovars have a more restricted host range that is associated with changes in the virulence plasmid pSV, accumulation of pseudogenes, and chromosome rearrangements. These changes in host-restricted Salmonella alter pathogen-host interactions such that host-restricted Salmonella organisms commonly cause systemic infections and are transmitted between host populations by asymptomatic carriers. The secondary consequences of efforts to eliminate host-restricted Salmonella serovars demonstrate that basic ecological principles govern the environmental niches occupied by these pathogens, making it impossible to thwart Salmonella infections without a clear understanding of the human, animal, and environmental reservoirs of these pathogens. Thus, transmission of S. enterica provides a compelling example of the One Health paradigm because reducing human infections will require the reduction of Salmonella in animals and limitation of transmission from the environment.

Evolution of Gustatory Receptor Gene Family Provides Insights into Adaptation to Diverse Host Plants in Nymphalid Butterflies.

PubMed

Suzuki, Hiromu C; Ozaki, Katsuhisa; Makino, Takashi; Uchiyama, Hironobu; Yajima, Shunsuke; Kawata, Masakado

2018-06-01

The host plant range of herbivorous insects is a major aspect of insect-plant interaction, but the genetic basis of host range expansion in insects is poorly understood. In butterflies, gustatory receptor genes (GRs) play important roles in host plant selection by ovipositing females. Since several studies have shown associations between the repertoire sizes of chemosensory gene families and the diversity of resource use, we hypothesized that the increase in the number of genes in the GR family is associated with host range expansion in butterflies. Here, we analyzed the evolutionary dynamics of GRs among related species, including the host generalist Vanessa cardui and three specialists. Although the increase of the GR repertoire itself was not observed, we found that the gene birth rate of GRs was the highest in the lineage leading to V. cardui compared with other specialist lineages. We also identified two taxon-specific subfamilies of GRs, characterized by frequent lineage-specific duplications and higher non-synonymous substitution rates. Together, our results suggest that frequent gene duplications in GRs, which might be involved in the detection of plant secondary metabolites, were associated with host range expansion in the V. cardui lineage. These evolutionary patterns imply that the capability to perceive various compounds during host selection was favored during adaptation to diverse host plants.

Role of the normal gut microbiota.

PubMed

Jandhyala, Sai Manasa; Talukdar, Rupjyoti; Subramanyam, Chivkula; Vuyyuru, Harish; Sasikala, Mitnala; Nageshwar Reddy, D

2015-08-07

Relation between the gut microbiota and human health is being increasingly recognised. It is now well established that a healthy gut flora is largely responsible for overall health of the host. The normal human gut microbiota comprises of two major phyla, namely Bacteroidetes and Firmicutes. Though the gut microbiota in an infant appears haphazard, it starts resembling the adult flora by the age of 3 years. Nevertheless, there exist temporal and spatial variations in the microbial distribution from esophagus to the rectum all along the individual's life span. Developments in genome sequencing technologies and bioinformatics have now enabled scientists to study these microorganisms and their function and microbe-host interactions in an elaborate manner both in health and disease. The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens. Several factors play a role in shaping the normal gut microbiota. They include (1) the mode of delivery (vaginal or caesarean); (2) diet during infancy (breast milk or formula feeds) and adulthood (vegan based or meat based); and (3) use of antibiotics or antibiotic like molecules that are derived from the environment or the gut commensal community. A major concern of antibiotic use is the long-term alteration of the normal healthy gut microbiota and horizontal transfer of resistance genes that could result in reservoir of organisms with a multidrug resistant gene pool.

Kupffer cell complement receptor clearance function and host defense.

PubMed

Loegering, D J

1986-01-01

Kupffer cells are well known to be important for normal host defense function. The development of methods to evaluate the in vivo function of specific receptors on Kupffer cells has made it possible to assess the role of these receptors in host defense. The rationale for studying complement receptors is based on the proposed important role of these receptors in host defense and on the observation that the hereditary deficiency of a complement receptor is associated with recurrent severe bacterial infections. The studies reviewed here demonstrate that forms of injury that are associated with depressed host defense including thermal injury, hemorrhagic shock, trauma, and surgery also cause a decrease in complement receptor clearance function. This decrease in Kupffer cell receptor clearance function was shown not to be the result of depressed hepatic blood flow or depletion of complement components. Complement receptor function was also depressed following the phagocytosis of particulates that are known to depress Kupffer cell host defense function. Endotoxemia and bacteremia also were associated with a depression of complement receptor function. Complement receptor function was experimentally depressed in uninjured animals by the phagocytosis of IgG-coated erythrocytes. There was a close association between the depression of complement receptor clearance function and increased susceptibility to the lethal effects of endotoxin and bacterial infection. These studies support the hypotheses that complement receptors on Kupffer cells are important for normal host defense and that depression of the function of these receptors impairs host defense.

HOST PLANT UTILIZATION, HOST RANGE OSCILLATIONS AND DIVERSIFICATION IN NYMPHALID BUTTERFLIES: A PHYLOGENETIC INVESTIGATION

PubMed Central

Nylin, Sören; Slove, Jessica; Janz, Niklas

2014-01-01

It has been suggested that phenotypic plasticity is a major factor in the diversification of life, and that variation in host range in phytophagous insects is a good model for investigating this claim. We explore the use of angiosperm plants as hosts for nymphalid butterflies, and in particular the evidence for past oscillations in host range and how they are linked to host shifts and to diversification. At the level of orders of plants, a relatively simple pattern of host use and host shifts emerges, despite the 100 million years of history of the family Nymphalidae. We review the evidence that these host shifts and the accompanying diversifications were associated with transient polyphagous stages, as suggested by the “oscillation hypothesis.” In addition, we investigate all currently polyphagous nymphalid species and demonstrate that the state of polyphagy is rare, has a weak phylogenetic signal, and a very apical distribution in the phylogeny; we argue that these are signs of its transient nature. We contrast our results with data from the bark beetles Dendroctonus, in which a more specialized host use is instead the apical state. We conclude that plasticity in host use is likely to have contributed to diversification in nymphalid butterflies. PMID:24372598

Characterization and storage of malaria antigens: Fractionation of Plasmodium knowlesi-induced antigens of rhesus monkey erythrocyte membranes*

PubMed Central

Schmidt-Ullrich, R.; Wallach, D. F. H.; Lightholder, J.

1979-01-01

In order to characterize parasite-induced host cell membrane antigens, the plasma membranes of Plasmodium knowlesi-infected rhesus erythrocytes have been compared with those of normal red cells and purified schizonts by immunochemical and biochemical techniques. Host cell membranes and schizonts were separated by differential centrifugation following nitrogen decompression. Isolated schizonts were further fractionated into several subcellular compartments. Crossed-immune electrophoresis, against monkey anti-schizont serum, of Triton X-100-solubilized material identified 7 P. knowlesi-specific antigens, of which 4 could be detected only in the host cell membranes. These membranes also contained 3 proteins, with relative molecular masses of 55 000, 65 000 and 90 000 and isoelectric points at pH 4.5, 4.5 and 5.2, respectively, which are lacking in normal membranes. Pulse-chase experiments with (14C)-glucosamine showed that these parasite-induced host cell membrane components are glycoproteins. ImagesFig. 1Fig. 2 PMID:120762

Optical Detection and Spectroscopy of Single Molecules in a Solid.

DTIC Science & Technology

1989-03-23

the optical absorption spectrum of single dopant molecules of pentacene in a p-terphenyl host crystal at liquid-helium temperatures. To achieve this...dopant molecules of pentacene in a p-terphenyl host crystal at liquid-helium temperatures. To achieve this, frequency-modulation spectroscopy was combined...solid would provide an important new tool for the study of local absorber-host interactions that would be uncomplicated by the normal averaging over

Evolutionary dynamics of host-plant specialization: a case study of the tribe Nymphalini.

PubMed

Janz, N; Nyblom, K; Nylin, S

2001-04-01

Two general patterns that have emerged from the intense studies on insect-host plant associations are a predominance of specialists over generalists and a taxonomic conservatism in host-plant use. In most insect-host plant systems, explanations for these patterns must be based on biases in the processes of host colonizations, host shifts, and specialization, rather than cospeciation. In the present paper, we investigate changes in host range in the nymphalid butterfly tribe Nymphalini, using parsimony optimizations of host-plant data on the butterfly phylogeny. In addition, we performed larval establishment tests to search for larval capacity to feed and survive on plants that have been lost from the female egg-laying repertoire. Optimizations suggested an ancestral association with Urticaceae, and most of the tested species showed a capacity to feed on Urtica dioica regardless of actual host-plant use. In addition, there was a bias among the successful establishments on nonhosts toward plants that are used as hosts by other species in the Nymphalini. An increased likelihood of colonizing ancestral or related plants could also provide an alternative explanation for the observed pattern that some plant families appear to have been colonized independently several times in the tribe. We also show that there is no directionality in host range evolution toward increased specialization, that is, specialization is not a dead end. Instead, changes in host range show a very dynamic pattern.

Nocardia species: host-parasite relationships.

PubMed Central

Beaman, B L; Beaman, L

1994-01-01

The nocardiae are bacteria belonging to the aerobic actinomycetes. They are an important part of the normal soil microflora worldwide. The type species, Nocardia asteroides, and N. brasiliensis, N. farcinica, N. otitidiscaviarum, N. nova, and N. transvalensis cause a variety of diseases in both normal and immunocompromised humans and animals. The mechanisms of pathogenesis are complex, not fully understood, and include the capacity to evade or neutralize the myriad microbicidal activities of the host. The relative virulence of N. asteroides correlates with the ability to inhibit phagosome-lysosome fusion in phagocytes; to neutralize phagosomal acidification; to detoxify the microbicidal products of oxidative metabolism; to modify phagocyte function; to grow within phagocytic cells; and to attach to, penetrate, and grow within host cells. Both activated macrophages and immunologically specific T lymphocytes constitute the major mechanisms for host resistance to nocardial infection, whereas B lymphocytes and humoral immunity do not appear to be as important in protecting the host. Thus, the nocardiae are facultative intracellular pathogens that can persist within the host, probably in a cryptic form (L-form), for life. Silent invasion of brain cells by some Nocardia strains can induce neurodegeneration in experimental animals; however, the role of nocardiae in neurodegenerative diseases in humans needs to be investigated. Images PMID:8055469

Host range and community structure of avian nest parasites in the genus Philornis (Diptera: Muscidae) on the island of Trinidad.

PubMed

Bulgarella, Mariana; Heimpel, George E

2015-09-01

Parasite host range can be influenced by physiological, behavioral, and ecological factors. Combining data sets on host-parasite associations with phylogenetic information of the hosts and the parasites involved can generate evolutionary hypotheses about the selective forces shaping host range. Here, we analyzed associations between the nest-parasitic flies in the genus Philornis and their host birds on Trinidad. Four of ten Philornis species were only reared from one species of bird. Of the parasite species with more than one host bird species, P. falsificus was the least specific and P. deceptivus the most specific attacking only Passeriformes. Philornis flies in Trinidad thus include both specialists and generalists, with varying degrees of specificity within the generalists. We used three quantities to more formally compare the host range of Philornis flies: the number of bird species attacked by each species of Philornis, a phylogenetically informed host specificity index (Poulin and Mouillot's S TD), and a branch length-based S TD. We then assessed the phylogenetic signal of these measures of host range for 29 bird species. None of these measures showed significant phylogenetic signal, suggesting that clades of Philornis did not differ significantly in their ability to exploit hosts. We also calculated two quantities of parasite species load for the birds - the parasite species richness, and a variant of the S TD index based on nodes rather than on taxonomic levels - and assessed the signal of these measures on the bird phylogeny. We did not find significant phylogenetic signal for the parasite species load or the node-based S TD index. Finally, we calculated the parasite associations for all bird pairs using the Jaccard index and regressed these similarity values against the number of nodes in the phylogeny separating bird pairs. This analysis showed that Philornis on Trinidad tend to feed on closely related bird species more often than expected by chance.

Host range diversification within the IncP-1 plasmid group

PubMed Central

Yano, Hirokazu; Rogers, Linda M.; Knox, Molly G.; Heuer, Holger; Smalla, Kornelia; Brown, Celeste J.

2013-01-01

Broad-host-range plasmids play a critical role in the spread of antibiotic resistance and other traits. In spite of increasing information about the genomic diversity of closely related plasmids, the relationship between sequence divergence and host range remains unclear. IncP-1 plasmids are currently classified into six subgroups based on the genetic distance of backbone genes. We investigated whether plasmids from two subgroups exhibit a different host range, using two IncP-1γ plasmids, an IncP-1β plasmid and their minireplicons. Efficiencies of plasmid establishment and maintenance were compared using five species that belong to the Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria. The IncP-1β plasmid replicated and persisted in all five hosts in the absence of selection. Of the two IncP-1γ plasmids, both were unable to replicate in alphaproteobacterial host Sphingobium japonicum, and one established itself in Agrobacterium tumefaciens but was very unstable. In contrast, both IncP-1γ minireplicons, which produced higher levels of replication initiation protein than the wild-type plasmids, replicated in all strains, suggesting that poor establishment of the native plasmids is in part due to suboptimal replication initiation gene regulation. The findings suggest that host ranges of distinct IncP-1 plasmids only partially overlap, which may limit plasmid recombination and thus result in further genome divergence. PMID:24002747

Canine and feline host ranges of canine parvovirus and feline panleukopenia virus: distinct host cell tropisms of each virus in vitro and in vivo.

PubMed Central

Truyen, U; Parrish, C R

1992-01-01

Canine parvovirus (CPV) emerged as an apparently new virus during the mid-1970s. The origin of CPV is unknown, but a variation from feline panleukopenia virus (FPV) or another closely related parvovirus is suspected. Here we examine the in vitro and in vivo canine and feline host ranges of CPV and FPV. Examination of three canine and six feline cell lines and mitogen-stimulated canine and feline peripheral blood lymphocytes revealed that CPV replicates in both canine and feline cells, whereas FPV replicates efficiently only in feline cells. The in vivo host ranges were unexpectedly complex and distinct from the in vitro host ranges. Inoculation of dogs with FPV revealed efficient replication in the thymus and, to some degree, in the bone marrow, as shown by virus isolation, viral DNA recovery, and Southern blotting and by strand-specific in situ hybridization. FPV replication could not be demonstrated in mesenteric lymph nodes or in the small intestine, which are important target tissues in CPV infection. Although CPV replicated well in all the feline cells tested in vitro, it did not replicate in any tissue of cats after intramuscular or intravenous inoculation. These results indicate that these viruses have complex and overlapping host ranges and that distinct tissue tropisms exist in the homologous and heterologous hosts. Images PMID:1323703

Has Sarcocystis neurona Dubey et al., 1991 (Sporozoa: Apicomplexa: Sarcocystidae) cospeciated with its intermediate hosts?

PubMed

Elsheikha, Hany M

2009-08-26

The question of how Sarcocystis neurona is able to overcome species barrier and adapt to new hosts is central to the understanding of both the evolutionary origin of S. neurona and the prediction of its field host range. Therefore, it is worth reviewing current knowledge on S. neurona host specificity. The available host range data for S. neurona are discussed in relation to a subject of evolutionary importance-specialist or generalist and its implications to understand the strategies of host adaptation. Current evidences demonstrate that a wide range of hosts exists for S. neurona. This parasite tends to be highly specific for its definitive host but much less so for its intermediate host (I.H.). The unique specificity of S. neurona for its definitive host may be mediated by a probable long coevolutionary relationship of the parasite and carnivores in a restricted ecological niche 'New World'. This might be taken as evidence that carnivores are the 'original' host group for S. neurona. Rather, the capacity of S. neurona to exploit an unusually large number of I.H. species probably indicates that S. neurona maintains non-specificity to its I.H. as an adaptive response to insure the survival of the parasite in areas in which the 'preferred' host is not available. This review concludes with the view that adaptation of S. neurona to a new host is a complex interplay that involves a large number of determinants.

Host tree resistance against the polyphagous

Treesearch

W. D. Morewood; K. Hoover; P. R. Neiner; J.R. McNeil; J. C. Sellmer

2004-01-01

Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae: Lamiini) is an invasive wood-boring beetle with an unusually broad host range and a proven ability to increase its host range as it colonizes new areas and encounters new tree species. The beetle is native to eastern Asia and has become an invasive pest in North America and Europe,...

Hosts of stolbur phytoplasmas in maize redness affected fields

USDA-ARS?s Scientific Manuscript database

The plant host range of a phytoplasma is strongly dependent on the host range of its insect vector. Maize redness in Serbia is caused by stolbur phytoplasma (subgroup 16SrXII-A) and is transmitted by the cixiid planthoper, Reptalus panzeri (Löw). R. panzeri was the only potential vector found to be ...

Eop1 from a Rubus strain of Erwinia amylovora functions as a host-range limiting factor.

PubMed

Asselin, J E; Bonasera, J M; Kim, J F; Oh, C-S; Beer, S V

2011-08-01

Strains of Erwinia amylovora, the bacterium causing the disease fire blight of rosaceous plants, are separated into two groups based on host range: Spiraeoideae and Rubus strains. Spiraeoideae strains have wide host ranges, infecting plants in many rosaceous genera, including apple and pear. In the field, Rubus strains infect the genus Rubus exclusively, which includes raspberry and blackberry. Based on comparisons of limited sequence data from a Rubus and a Spiraeoideae strain, the gene eop1 was identified as unusually divergent, and it was selected as a possible host specificity factor. To test this, eop1 genes from a Rubus strain and a Spiraeoideae strain were cloned and mutated. Expression of the Rubus-strain eop1 reduced the virulence of E. amylovora in immature pear fruit and in apple shoots. Sequencing the orfA-eop1 regions of several strains of E. amylovora confirmed that forms of eop1 are conserved among strains with similar host ranges. This work provides evidence that eop1 from a Rubus-specific strain can function as a determinant of host specificity in E. amylovora.

A model for the energy band gap of GaSbxAs1-x and InSbxAs1-x in the whole composition range

NASA Astrophysics Data System (ADS)

Zhao, Chuan-Zhen; Ren, He-Yu; Wei, Tong; Wang, Sha-Sha; Wang, Jun

2018-04-01

The band gap evolutions of GaSbxAs1-x and InSbxAs1-x in the whole composition range are investigated. It is found that the band gap evolutions of GaSbxAs1-x and InSbxAs1-x are determined by two factors. One is the impurity-host interaction in the As-rich and Sb-rich composition ranges. The other is the intraband coupling within the conduction band and separately within the valence band in the moderate composition range. Based on the band gap evolutions of GaSbxAs1-x and InSbxAs1-x, a model is established. In addition, it is found that the impurity-host interaction is determined by not only the mismatches in size and electronegativity between the introduced atoms in the host material and the anions of the host material, but also the difference in electronegativity between the introduced atoms in the host material and the cations of the host material.

Phytonutrients as non-nutritive feed additives to enhance growth and host immunity in broiler chickens

USDA-ARS?s Scientific Manuscript database

The gut represents a continuously evolving ecosystem where a dynamic interaction between host immune, neuroendocrine and entero-endocrine cells and the gut microbiota influences normal physiological development and homeostasis. New antibiotic regulatory policies and cage-free rearing systems in pou...

Split Personality of a Potyvirus: To Specialize or Not to Specialize?

PubMed Central

Kehoe, Monica A.; Coutts, Brenda A.; Buirchell, Bevan J.; Jones, Roger A. C.

2014-01-01

Bean yellow mosaic virus (BYMV), genus Potyvirus, has an extensive natural host range encompassing both dicots and monocots. Its phylogenetic groups were considered to consist of an ancestral generalist group and six specialist groups derived from this generalist group during plant domestication. Recombination was suggested to be playing a role in BYMV's evolution towards host specialization. However, in subsequent phylogenetic analysis of whole genomes, group names based on the original hosts of isolates within each of them were no longer supported. Also, nine groups were found and designated I-IX. Recombination analysis was conducted on the complete coding regions of 33 BYMV genomes and two genomes of the related Clover yellow vein virus (CYVV). This analysis found evidence for 12 firm recombination events within BYMV phylogenetic groups I–VI, but none within groups VII–IX or CYVV. The greatest numbers of recombination events within a sequence (two or three each) occurred in four groups, three which formerly constituted the single ancestral generalist group (I, II and IV), and group VI. The individual sequences in groups III and V had one event each. These findings with whole genomes are consistent with recombination being associated with expanding host ranges, and call into question the proposed role of recombination in the evolution of BYMV, where it was previously suggested to play a role in host specialization. Instead, they (i) indicate that recombination explains the very broad natural host ranges of the three BYMV groups which infect both monocots and dicots (I, II, IV), and (ii) suggest that the three groups with narrow natural host ranges (III, V, VI) which also showed recombination now have the potential to reduce host specificity and broaden their natural host ranges. PMID:25148372

Rare earth elements geochemistry in springs from Taftan geothermal area SE Iran

NASA Astrophysics Data System (ADS)

Shakeri, Ata; Ghoreyshinia, Sayedkazem; Mehrabi, Behzad; Delavari, Morteza

2015-10-01

Concentrations of rare earth elements (REEs) were determined in springs and andesitic-dacitic rocks of Taftan geothermal field. Hydrochemical results of major ions indicate that thermal springs are Na-SO4-Cl and Ca-SO4-Cl types. Concentrations of REEs are in ranges of 10- 4 to 1.2 and 49 to 62 times of chondrite for springwater and rock samples, respectively. The thermal (STS and TTS) and the cold (APS) springs with low pH values exhibit a very high REE contents (0.64 to 3.15 mg/l). Saturation index indicates that Fe and Al phases can control dissolved REE concentration in FTS and PF cold springs. The speciation of REE complexes indicates dominant presence of LnSO4+ and free ion in the Taftan thermal springs. In APS cold spring with pH 4, fluoride complexes are dominate over the free ion and sulfate species, while in PF and FTS cold springs with pH 6.4 and 7, respectively, carbonate complexes (LnCO3+) are predominant species. Chondrite-normalized pattern for the low-pH waters show very distinctive gull-wing patterns, characteristic feature of acid-sulfate geothermal systems, and are similar to those of the host rocks. Chemical characteristics of rare earth elements in spring and volcanic rock samples indicate that REEs are originated from the andesitic-dacitic host rocks. Whole-rock-normalized REE patterns and petrographic evidences show that rare earth elements leached mainly from marginal alteration of minerals and matrix decomposition in volcanic rocks. In chondrite-normalized REE patterns, significant negative Eu anomaly in the cold springs compare to the thermal and acidic springs indicates that alteration of plagioclase is more intense in the later, corresponding to increasing in temperature and acidic state of reactant water.

Sating a Voracious Appetite: The Tidal Interaction of Close-in Planets with their Host Stars

NASA Astrophysics Data System (ADS)

Matsakos, Titos; Königl, Arieh

2015-12-01

Transit observations of the apparent angle between the stellar spin and the vector normal to the planetary orbital plane suggest that cool stars are preferably aligned systems even as hot stars exhibit a large range of obliquities. In addition, as was demonstrated recently by Mazeh et al., the distribution of planet periods as a function of mass exhibits a dearth of sub-Jupiter--mass planets at < 4 days periods, with the boundary of the sparsely populated region in phase space having a roughly conical shape. We suggest that both of these seemingly disparate features are manifestations of the tidal interaction between close-in planets and their host stars. We attribute the dichotomy in the obliquity properties to the effect of an early population of hot Jupiters that got stranded near the inner edge of a primordially misaligned protoplanetary disk and subsequently (on a timescale < 1 Gyr) ingested by the host star. The relative magnitudes of the stellar spin and planetary orbital angular momenta at the time of ingestion determined whether the hot Jupiter could realign the host; this did not happen in the case of hot stars because of inefficient magnetic braking and a comparatively high moment of inertia. We interpret the dearth of intermediate-mass planets at short periods by considering the tidal evolution of planets that arrive on highly eccentric orbits at later (> 1 Gyr) times and become circularized at radii of a few times the Roche limit.

Pseudotachylyte: Reading the Record of Paleoseismicity in Low-Angle Normal Faults

NASA Astrophysics Data System (ADS)

Smith, D. M.; Goodwin, L. B.; Feinberg, J. M.; Ellis, A. P.

2012-12-01

Whether or not low-angle normal faults (LANFs, dipping <30°) can produce earthquakes is hotly debated. Pseudotachylyte - rapidly quenched frictional melt generated during seismic failure - has been noted in several LANF sites but not extensively studied. We recently documented significant pseudotachylyte exposures in both the South Mountains and Catalina-Rincon metamorphic core complexes of Arizona. In both field areas, pseudotachylyte is located below detachment faults, where it is best exposed in fractured areas beneath chlorite breccia zones. Generation veins dip 7-24°, are locally parallel to host rock foliations, and range from 1 mm to 3 cm thick. Where subvertical exposures are available, generation and injection veins either form networks up to 1 m thick or are stacked, such that multiple veins spaced < 1m apart are exposed in zones 2 to 3 m thick. Outcrops do not permit mapping of pseudotachylytes' full lateral extent, but do allow a minimum length of 50 m oblique to strike to be estimated. The magnitude of pseudotachylyte exposure in these core complexes implies significant seismicity. A key question is whether the generation surfaces were in their present orientations when they failed seismically. To answer this, we are applying a fault paleogeometry test. The cornerstone of this test is a comparison of two paleomagnetic vectors. The first will be determined through standard paleomagnetic analyses of oriented pseudotachylyte samples. The second will represent the vector expected if no LANF rotation has occurred and will be determined through correlation of a sample's 40Ar/39Ar age with its coeval magnetic pole location. Any discrepancy between the vectors will be interpreted to represent rotation of the fault since seismicity. Anderson-Byerlee compatible slip will be supported by discrepancies requiring a seismically active dip >30°. An active dip of <30° suggests that additional factors have reduced effective stress and/or frictional resistance to allow seismicity. A third, similarly extensive zone of pseudotachylyte veins in Central Otago, New Zealand will be included with our Arizona sites in this analysis. Previous work in this location shows more than 100 veins dipping 10-30°, from 1- 3 cm thick, extending up to 200 m along strike (Barker, 2005). The Otago site emphasizes seismicity as a component of LANF development in different tectonic regions, and will allow comparison of LANF pseudotachylytes of disparate host rock and ages (Miocene in U.S. sites, Cretaceous in NZ). Preliminary data demonstrate a range in magnetic characteristics of the samples we have collected. Veins within felsic granodiorite and alaskite in the South Mountains show susceptibilities ranging from 0.48 -1.06 x 10-3 SI. These values are indistinguishable from host rock susceptibilities (0.48 - 1.32 x 10-3 SI). In contrast, Rincon pseudotachylyte has magnetic susceptibilities ranging from 29.3 to >80.0 x 10-3 SI and porphyroclastic gneiss host rock values are a considerably lower 7.44 - 8.64 x 10-3 SI. We therefore anticipate this test will only be successfully applied toward some of our samples. Our presentation will include both descriptions of pseudotachlylyte zones and networks and preliminary paleomagnetic data.

New Hepatitis B Virus of Cranes That Has an Unexpected Broad Host Range

PubMed Central

Prassolov, Alexej; Hohenberg, Heinz; Kalinina, Tatyana; Schneider, Carola; Cova, Lucyna; Krone, Oliver; Frölich, Kai; Will, Hans; Sirma, Hüseyin

2003-01-01

All hepadnaviruses known so far have a very limited host range, restricted to their natural hosts and a few closely related species. This is thought to be due mainly to sequence divergence in the large envelope protein and species-specific differences in host components essential for virus propagation. Here we report an infection of cranes with a novel hepadnavirus, designated CHBV, that has an unexpectedly broad host range and is only distantly evolutionarily related to avihepadnaviruses of related hosts. Direct DNA sequencing of amplified CHBV DNA as well a sequencing of cloned viral genomes revealed that CHBV is most closely related to, although distinct from, Ross' goose hepatitis B virus (RGHBV) and slightly less closely related to duck hepatitis B virus (DHBV). Phylogenetically, cranes are very distant from geese and ducks and are most closely related to herons and storks. Naturally occurring hepadnaviruses in the last two species are highly divergent in sequence from RGHBV and DHBV and do not infect ducks or do so only marginally. In contrast, CHBV from crane sera and recombinant CHBV produced from LMH cells infected primary duck hepatocytes almost as efficiently as DHBV did. This is the first report of a rather broad host range of an avihepadnavirus. Our data imply either usage of similar or identical entry pathways and receptors by DHBV and CHBV, unusual host and virus adaptation mechanisms, or divergent evolution of the host genomes and cellular components required for virus propagation. PMID:12525630

New hepatitis B virus of cranes that has an unexpected broad host range.

PubMed

Prassolov, Alexej; Hohenberg, Heinz; Kalinina, Tatyana; Schneider, Carola; Cova, Lucyna; Krone, Oliver; Frölich, Kai; Will, Hans; Sirma, Hüseyin

2003-02-01

All hepadnaviruses known so far have a very limited host range, restricted to their natural hosts and a few closely related species. This is thought to be due mainly to sequence divergence in the large envelope protein and species-specific differences in host components essential for virus propagation. Here we report an infection of cranes with a novel hepadnavirus, designated CHBV, that has an unexpectedly broad host range and is only distantly evolutionarily related to avihepadnaviruses of related hosts. Direct DNA sequencing of amplified CHBV DNA as well a sequencing of cloned viral genomes revealed that CHBV is most closely related to, although distinct from, Ross' goose hepatitis B virus (RGHBV) and slightly less closely related to duck hepatitis B virus (DHBV). Phylogenetically, cranes are very distant from geese and ducks and are most closely related to herons and storks. Naturally occurring hepadnaviruses in the last two species are highly divergent in sequence from RGHBV and DHBV and do not infect ducks or do so only marginally. In contrast, CHBV from crane sera and recombinant CHBV produced from LMH cells infected primary duck hepatocytes almost as efficiently as DHBV did. This is the first report of a rather broad host range of an avihepadnavirus. Our data imply either usage of similar or identical entry pathways and receptors by DHBV and CHBV, unusual host and virus adaptation mechanisms, or divergent evolution of the host genomes and cellular components required for virus propagation.

Is the nestedness of metazoan parasite assemblages of marine fishes from the southeastern Pacific coast a pattern associated with the geographical distributional range of the host?

PubMed

González, M T; Oliva, M E

2009-04-01

Nested structure is a pattern originally described in island biogeography to characterize how a set of species is distributed among a set of islands. In parasite communities, nestedness has been intensively studied among individual fish from a locality. However, nested patterns among parasite assemblages from different host populations (localities) have scarcely been investigated. We recorded the occurrence of parasites in 9 fish species widely distributed along the southeastern Pacific coast to determine whether the ecto- and endoparasite assemblages of marine fishes show a nested structure associated with host distributional range. Nestedness was tested using Brualdi-Sanderson index of discrepancy (BR); and 5 null models incorporated in a 'Nestedness' programme (Ulrich, 2006). The ecto- and endoparasite richness do not show similar patterns of latitudinal gradients among fish hosts, with 33-66% of analysed ectoparasite assemblages, and 25-75% of endoparasite assemblages showing nested structures through the host distributional range. For ectoparasites, species richness gradients and nested structure (when present) might be associated with decreased host densities or could reflect negative environmental conditions in the distributional border of the host species, whereas for endoparasites might be caused by geographical breaks of prey or changes in prey availability (intermediate hosts). The sampled extension of the distributional range of the host species, as well as the lack of specificity of some parasites, could influence the detection of nestedness.

Association and Host Selectivity in Multi-Host Pathogens

PubMed Central

Malpica, José M.; Sacristán, Soledad; Fraile, Aurora; García-Arenal, Fernando

2006-01-01

The distribution of multi-host pathogens over their host range conditions their population dynamics and structure. Also, host co-infection by different pathogens may have important consequences for the evolution of hosts and pathogens, and host-pathogen co-evolution. Hence it is of interest to know if the distribution of pathogens over their host range is random, or if there are associations between hosts and pathogens, or between pathogens sharing a host. To analyse these issues we propose indices for the observed patterns of host infection by pathogens, and for the observed patterns of co-infection, and tests to analyse if these patterns conform to randomness or reflect associations. Applying these tests to the prevalence of five plant viruses on 21 wild plant species evidenced host-virus associations: most hosts and viruses were selective for viruses and hosts, respectively. Interestingly, the more host-selective viruses were the more prevalent ones, suggesting that host specialisation is a successful strategy for multi-host pathogens. Analyses also showed that viruses tended to associate positively in co-infected hosts. The developed indices and tests provide the tools to analyse how strong and common are these associations among different groups of pathogens, which will help to understand and model the population biology of multi-host pathogens. PMID:17183670

Cuckoos host range is associated positively with distribution range and negatively with evolutionary uniqueness.

PubMed

Morelli, Federico; Benedetti, Yanina; Møller, Anders Pape; Liang, Wei; Carrascal, Luis M

2018-05-01

The evolutionary distinctiveness (ED) score is a measure of phylogenetic isolation that quantifies the evolutionary uniqueness of a species. Here, we compared the ED score of parasitic and non-parasitic cuckoo species world-wide, to understand whether parental care or parasitism represents the largest amount of phylogenetic uniqueness. Next, we focused only on 46 cuckoo species characterized by brood parasitism with a known number of host species, and we explored the associations among ED score, number of host species and breeding range size for these species. We assessed these associations using phylogenetic generalized least squares (PGLS) models, taking into account the phylogenetic signal. Parasitic cuckoo species were not more unique in terms of ED than non-parasitic species. However, we found a significant negative association between the evolutionary uniqueness and host range and a positive correlation between the number of host species and range size of parasitic cuckoos, probably suggesting a passive sampling of hosts by parasitic species as the breeding range broadens. The findings of this study showed that more generalist brood parasites occupied very different positions in a phylogenetic tree, suggesting that they have evolved independently within the Cuculiformes order. Finally, we demonstrated that specialist cuckoo species also represent the most evolutionarily unique species in the order of Cuculiformes. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.

Geographically structured host specificity is caused by the range expansions and host shifts of a symbiotic fungus.

PubMed

Wolfe, Benjamin E; Pringle, Anne

2012-04-01

The inability to associate with local species may constrain the spread of mutualists arriving to new habitats, but the fates of introduced, microbial mutualists are largely unknown. The deadly poisonous ectomycorrhizal fungus Amanita phalloides (the death cap) is native to Europe and introduced to the East and West Coasts of North America. By cataloging host associations across the two continents, we record dramatic changes in specificity among the three ranges. On the East Coast, where the fungus is restricted in its distribution, it associates almost exclusively with pines, which are rarely hosts of A. phalloides in its native range. In California, where the fungus is widespread and locally abundant, it associates almost exclusively with oaks, mirroring the host associations observed in Europe. The most common host of the death cap in California is the endemic coast live oak (Quercus agrifolia), and the current distribution of A. phalloides appears constrained within the distribution of Q. agrifolia. In California, host shifts to native plants are also associated with a near doubling in the resources allocated to sexual reproduction and a prolonged fruiting period; mushrooms are twice as large as they are elsewhere and mushrooms are found throughout the year. Host and niche shifts are likely to shape the continuing range expansion of A. phalloides and other ectomycorrhizal fungi introduced across the world.

Geographically structured host specificity is caused by the range expansions and host shifts of a symbiotic fungus

PubMed Central

Wolfe, Benjamin E; Pringle, Anne

2012-01-01

The inability to associate with local species may constrain the spread of mutualists arriving to new habitats, but the fates of introduced, microbial mutualists are largely unknown. The deadly poisonous ectomycorrhizal fungus Amanita phalloides (the death cap) is native to Europe and introduced to the East and West Coasts of North America. By cataloging host associations across the two continents, we record dramatic changes in specificity among the three ranges. On the East Coast, where the fungus is restricted in its distribution, it associates almost exclusively with pines, which are rarely hosts of A. phalloides in its native range. In California, where the fungus is widespread and locally abundant, it associates almost exclusively with oaks, mirroring the host associations observed in Europe. The most common host of the death cap in California is the endemic coast live oak (Quercus agrifolia), and the current distribution of A. phalloides appears constrained within the distribution of Q. agrifolia. In California, host shifts to native plants are also associated with a near doubling in the resources allocated to sexual reproduction and a prolonged fruiting period; mushrooms are twice as large as they are elsewhere and mushrooms are found throughout the year. Host and niche shifts are likely to shape the continuing range expansion of A. phalloides and other ectomycorrhizal fungi introduced across the world. PMID:22134645

Nonprimate Hepaciviruses in Domestic Horses, United Kingdom

PubMed Central

Lyons, Sinéad; Kapoor, Amit; Sharp, Colin; Schneider, Bradley S.; Wolfe, Nathan D.; Culshaw, Geoff; Corcoran, Brendan; McGorum, Bruce C.

2012-01-01

Although the origin of hepatitis C virus infections in humans remains undetermined, a close homolog of this virus, termed canine hepacivirus (CHV) and found in respiratory secretions of dogs, provides evidence for a wider distribution of hepaciviruses in mammals. We determined frequencies of active infection among dogs and other mammals in the United Kingdom. Samples from dogs (46 respiratory, 99 plasma, 45 autopsy samples) were CHV negative by PCR. Screening of 362 samples from cats, horses, donkeys, rodents, and pigs identified 3 (2%) positive samples from 142 horses. These samples were genetically divergent from CHV and nonprimate hepaciviruses that horses were infected with during 2012 in New York state, USA. Investigation of infected horses demonstrated nonprimate hepacivirus persistence, high viral loads in plasma (105–107 RNA copies/mL), and liver function test results usually within reference ranges, although several values ranged from high normal to mildly elevated. Disease associations and host range of nonprimate hepaciviruses warrant further investigation. PMID:23171728

Proximate mechanism of behavioral manipulation of an orb-weaver spider host by a parasitoid wasp

PubMed Central

Gonzaga, Marcelo Oliveira; de Oliveira, Leandro Licursi; Sperber, Carlos Frankl

2017-01-01

Some ichneumonid wasps induce modifications in the web building behavior of their spider hosts to produce resistant “cocoon” webs. These structures hold and protect the wasp’s cocoon during pupa development. The mechanism responsible for host manipulation probably involves the inoculation of psychotropic chemicals by the parasitoid larva during a specific developmental period. Recent studies indicate that some spiders build cocoon webs similar to those normally built immediately before ecdysis, suggesting that this substance might be a molting hormone or a precursor chemical of this hormone. Here, we report that Cyclosa spider species exhibiting modified behavior presented higher 20-OH-ecdysone levels than parasitized spiders acting normally or unparasitized individuals. We suggest that the lack of control that spiders have when constructing modified webs can be triggered by anachronic activation of ecdysis. PMID:28158280

Feasibility of confocal endomicroscopy in the diagnosis of pediatric gastrointestinal disorders

PubMed Central

Venkatesh, Krishnappa; Cohen, Marta; Evans, Clair; Delaney, Peter; Thomas, Steven; Taylor, Christopher; Abou-Taleb, Ashraf; Kiesslich, Ralf; Thomson, Mike

2009-01-01

AIM: To evaluate the feasibility and utility of confocal laser endomicroscopy (CLE) in the description of normal gastrointestinal (GI) mucosa and in the diagnosis of GI disorders in children, in comparison to histology. METHODS: Forty-four patients (19 female) median age 10.9 years (range 0.7-16.6 years) with suspected or known GI pathology underwent esophago-gastro-duodenoscopy (OGD) (n = 36) and/or ileocolonoscopy (IC) (n = 31) with CLE using sodium fluorescein and acriflavine as contrast agents. Histological sections were compared with same site confocal images by two experienced pediatric and GI histopathologists and endoscopists, respectively. RESULTS: Duodenum and ileum were intubated in all but one patient undergoing OGD and IC. The median procedure time was 16.4 min (range 7-25 min) for OGD and 27.9 min (range 15-45 min) for IC. A total of 4798 confocal images were compared with 153 biopsies from the upper GI tract from 36 procedures, and 4661 confocal images were compared with 188 biopsies from the ileocolon from 31 procedures. Confocal images were comparable to conventional histology both in normal and in pathological conditions such as esophagitis, Helicobacter pylori gastritis, celiac disease, inflammatory bowel disease, colonic heterotopia, and graft versus host disease. CONCLUSION: CLE offers the prospect of targeting biopsies to abnormal mucosa, thereby increasing diagnostic yield, reducing the number of biopsies, decreasing the burden on the histopathological services, and reducing costs. PMID:19437560

Diversity and host range of foliar fungal endophytes: are tropical leaves biodiversity hotspots?

PubMed

Arnold, A Elizabeth; Lutzoni, F

2007-03-01

Fungal endophytes are found in asymptomatic photosynthetic tissues of all major lineages of land plants. The ubiquity of these cryptic symbionts is clear, but the scale of their diversity, host range, and geographic distributions are unknown. To explore the putative hyperdiversity of tropical leaf endophytes, we compared endophyte communities along a broad latitudinal gradient from the Canadian arctic to the lowland tropical forest of central Panama. Here, we use molecular sequence data from 1403 endophyte strains to show that endophytes increase in incidence, diversity, and host breadth from arctic to tropical sites. Endophyte communities from higher latitudes are characterized by relatively few species from many different classes of Ascomycota, whereas tropical endophyte assemblages are dominated by a small number of classes with a very large number of endophytic species. The most easily cultivated endophytes from tropical plants have wide host ranges, but communities are dominated by a large number of rare species whose host range is unclear. Even when only the most easily cultured species are considered, leaves of tropical trees represent hotspots of fungal species diversity, containing numerous species not yet recovered from other biomes. The challenge remains to recover and identify those elusive and rarely cultured taxa with narrower host ranges, and to elucidate the ecological roles of these little-known symbionts in tropical forests.

Experience-dependent mushroom body plasticity in butterflies: consequences of search complexity and host range

PubMed Central

Janz, Niklas; Schäpers, Alexander; Gamberale-Stille, Gabriella

2017-01-01

An ovipositing insect experiences many sensory challenges during her search for a suitable host plant. These sensory challenges become exceedingly pronounced when host range increases, as larger varieties of sensory inputs have to be perceived and processed in the brain. Neural capacities can be exceeded upon information overload, inflicting costs on oviposition accuracy. One presumed generalist strategy to diminish information overload is the acquisition of a focused search during its lifetime based on experiences within the current environment, a strategy opposed to a more genetically determined focus expected to be seen in relative specialists. We hypothesized that a broader host range is positively correlated with mushroom body (MB) plasticity, a brain structure related to learning and memory. To test this hypothesis, butterflies with diverging host ranges (Polygonia c-album, Aglais io and Aglais urticae) were subjected to differential environmental complexities for oviposition, after which ontogenetic MB calyx volume differences were compared among species. We found that the relative generalist species exhibited remarkable plasticity in ontogenetic MB volumes; MB growth was differentially stimulated based on the complexity of the experienced environment. For relative specialists, MB volume was more canalized. All in all, this study strongly suggests an impact of host range on brain plasticity in Nymphalid butterflies. PMID:29093221

Effects of host species and population density on Anoplophora glabripennis flight propensity

Treesearch

Joseph A. Francese; David R. Lance; Baode Wang; Zhichun Xu; Alan J. Sawyer; Victor C. Mastro

2007-01-01

Anoplophora glabripennis Motschulsky (Coleoptera: Cerambycidae), the Asian longhorned beetle (ALB) is a pest of hardwoods in its native range of China. While the host range of this pest has been studied extensively, its mechanisms for host selection are still unknown. Our goal was to study the factors influencing movement and orientation of adult ALB...

Host specialization in ticks and transmission of tick-borne diseases: a review

PubMed Central

McCoy, Karen D.; Léger, Elsa; Dietrich, Muriel

2013-01-01

Determining patterns of host use, and the frequency at which these patterns change, are of key importance if we are to understand tick population dynamics, the evolution of tick biodiversity, and the circulation and evolution of associated pathogens. The question of whether ticks are typically host specialists or host generalists has been subject to much debate over the last half-century. Indeed, early research proposed that morphological diversity in ticks was linked to host specific adaptations and that most ticks were specialists. Later work disputed this idea and suggested that ticks are largely limited by biogeographic conditions and tend to use all locally available host species. The work presented in this review suggests that the actual answer likely lies somewhere between these two extremes. Although recent observational studies support the view that phylogenetically diverse host species share ticks when found on similar ecological ranges, theory on host range evolution predicts that host specialization should evolve in ticks given their life history characteristics. Contemporary work employing population genetic tools to examine host-associated population structure in several tick systems support this prediction and show that simple species records are not enough to determine whether a parasite is a true host generalist; host specialization does evolve in ticks at local scales, but may not always lead to speciation. Ticks therefore seem to follow a pattern of being global generalists, local specialists. Given this, the notion of host range needs to be modified from an evolutionary perspective, where one simply counts the number of hosts used across the geographic distribution, to a more ecological view, where one considers host use at a local scale, if we are to better understand the circulation of tick-borne pathogens and exposure risks for humans and livestock. PMID:24109592

Host specialization in ticks and transmission of tick-borne diseases: a review.

PubMed

McCoy, Karen D; Léger, Elsa; Dietrich, Muriel

2013-01-01

Determining patterns of host use, and the frequency at which these patterns change, are of key importance if we are to understand tick population dynamics, the evolution of tick biodiversity, and the circulation and evolution of associated pathogens. The question of whether ticks are typically host specialists or host generalists has been subject to much debate over the last half-century. Indeed, early research proposed that morphological diversity in ticks was linked to host specific adaptations and that most ticks were specialists. Later work disputed this idea and suggested that ticks are largely limited by biogeographic conditions and tend to use all locally available host species. The work presented in this review suggests that the actual answer likely lies somewhere between these two extremes. Although recent observational studies support the view that phylogenetically diverse host species share ticks when found on similar ecological ranges, theory on host range evolution predicts that host specialization should evolve in ticks given their life history characteristics. Contemporary work employing population genetic tools to examine host-associated population structure in several tick systems support this prediction and show that simple species records are not enough to determine whether a parasite is a true host generalist; host specialization does evolve in ticks at local scales, but may not always lead to speciation. Ticks therefore seem to follow a pattern of being global generalists, local specialists. Given this, the notion of host range needs to be modified from an evolutionary perspective, where one simply counts the number of hosts used across the geographic distribution, to a more ecological view, where one considers host use at a local scale, if we are to better understand the circulation of tick-borne pathogens and exposure risks for humans and livestock.

Use of Comparative Genomics-Based Markers for Discrimination of Host Specificity in Fusarium oxysporum.

PubMed

van Dam, Peter; de Sain, Mara; Ter Horst, Anneliek; van der Gragt, Michelle; Rep, Martijn

2018-01-01

The polyphyletic nature of many formae speciales of Fusarium oxysporum prevents molecular identification of newly encountered strains based on conserved, vertically inherited genes. Alternative molecular detection methods that could replace labor- and time-intensive disease assays are therefore highly desired. Effectors are functional elements in the pathogen-host interaction and have been found to show very limited sequence diversity between strains of the same forma specialis , which makes them potential markers for host-specific pathogenicity. We therefore compared candidate effector genes extracted from 60 existing and 22 newly generated genome assemblies, specifically targeting strains affecting cucurbit plant species. Based on these candidate effector genes, a total of 18 PCR primer pairs were designed to discriminate between each of the seven Cucurbitaceae-affecting formae speciales When tested on a collection of strains encompassing different clonal lineages of these formae speciales , nonpathogenic strains, and strains of other formae speciales , they allowed clear recognition of the host range of each evaluated strain. Within Fusarium oxysporum f. sp. melonis more genetic variability exists than anticipated, resulting in three F. oxysporum f. sp. melonis marker patterns that partially overlapped with the cucurbit-infecting Fusarium oxysporum f. sp. cucumerinum , Fusarium oxysporum f. sp. niveum , Fusarium oxysporum f. sp. momordicae , and/or Fusarium oxysporum f. sp. lagenariae For F. oxysporum f. sp. niveum , a multiplex TaqMan assay was evaluated and was shown to allow quantitative and specific detection of template DNA quantities as low as 2.5 pg. These results provide ready-to-use marker sequences for the mentioned F. oxysporum pathogens. Additionally, the method can be applied to find markers distinguishing other host-specific forms of F. oxysporum IMPORTANCE Pathogenic strains of Fusarium oxysporum are differentiated into formae speciales based on their host range, which is normally restricted to only one or a few plant species. However, horizontal gene transfer between strains in the species complex has resulted in a polyphyletic origin of host specificity in many of these formae speciales This hinders accurate and rapid pathogen detection through molecular methods. In our research, we compared the genomes of 88 strains of F. oxysporum with each other, specifically targeting virulence-related genes that are typically highly similar within each forma specialis Using this approach, we identified marker sequences that allow the discrimination of F. oxysporum strains affecting various cucurbit plant species through different PCR-based methods. Copyright © 2017 American Society for Microbiology.

Complete Host Range Testing on Common Reed with Potential Biological Control Agents and Investigation into Biological Control for Flowering Rush

DTIC Science & Technology

2016-07-01

ER D C/ EL C R- 16 -5 Aquatic Plant Control Research Program Complete Host Range Testing on Common Reed with Potential Biological...client/default. Aquatic Plant Control Research Program ERDC/EL CR-16-5 July 2016 Complete Host Range Testing on Common Reed with Potential...and started with sequential no-choice oviposition tests. So far, no eggs were found on any of the 22 test plants offered. The authors also found the

A few good reasons why species-area relationships do not work for parasites.

PubMed

Strona, Giovanni; Fattorini, Simone

2014-01-01

Several studies failed to find strong relationships between the biological and ecological features of a host and the number of parasite species it harbours. In particular, host body size and geographical range are generally only weak predictors of parasite species richness, especially when host phylogeny and sampling effort are taken into account. These results, however, have been recently challenged by a meta-analytic study that suggested a prominent role of host body size and range extent in determining parasite species richness (species-area relationships). Here we argue that, in general, results from meta-analyses should not discourage researchers from investigating the reasons for the lack of clear patterns, thus proposing a few tentative explanations to the fact that species-area relationships are infrequent or at least difficult to be detected in most host-parasite systems. The peculiar structure of host-parasite networks, the enemy release hypothesis, the possible discrepancy between host and parasite ranges, and the evolutionary tendency of parasites towards specialization may explain why the observed patterns often do not fit those predicted by species-area relationships.

Eilat virus host range restriction is present at multiple levels of the virus life cycle.

PubMed

Nasar, Farooq; Gorchakov, Rodion V; Tesh, Robert B; Weaver, Scott C

2015-01-15

Most alphaviruses are mosquito-borne and exhibit a broad host range, infecting many different vertebrates, including birds, rodents, equids, humans, and nonhuman primates. This ability of most alphaviruses to infect arthropods and vertebrates is essential for their maintenance in nature. Recently, a new alphavirus, Eilat virus (EILV), was described, and in contrast to all other mosquito-borne viruses, it is unable to replicate in vertebrate cell lines. Investigations into the nature of its host range restriction showed the inability of genomic EILV RNA to replicate in vertebrate cells. Here, we investigated whether the EILV host range restriction is present at the entry level and further explored the viral factors responsible for the lack of genomic RNA replication. Utilizing Sindbis virus (SINV) and EILV chimeras, we show that the EILV vertebrate host range restriction is also manifested at the entry level. Furthermore, the EILV RNA replication restriction is independent of the 3' untranslated genome region (UTR). Complementation experiments with SINV suggested that RNA replication is restricted by the inability of the EILV nonstructural proteins to form functional replicative complexes. These data demonstrate that the EILV host range restriction is multigenic, involving at least one gene from both nonstructural protein (nsP) and structural protein (sP) open reading frames (ORFs). As EILV groups phylogenetically within the mosquito-borne virus clade of pathogenic alphaviruses, our findings have important evolutionary implications for arboviruses. Our work explores the nature of host range restriction of the first "mosquito-only alphavirus," EILV. EILV is related to pathogenic mosquito-borne viruses (Eastern equine encephalitis virus [EEEV], Western equine encephalitis virus [WEEV], Venezuelan equine encephalitis virus [VEEV], and Chikungunya virus [CHIKV]) that cause severe disease in humans. Our data demonstrate that EILV is restricted both at entry and genomic RNA replication levels in vertebrate cells. These findings have important implications for arbovirus evolution and will help elucidate the viral factors responsible for the broad host range of pathogenic mosquito-borne alphaviruses, facilitate vaccine development, and inform potential strategies to reduce/prevent alphavirus transmission. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The roles of geography and founder effects in promoting host-associated differentiation in the generalist bogus yucca moth Prodoxus decipiens.

PubMed

Darwell, C T; Fox, K A; Althoff, D M

2014-12-01

There is ample evidence that host shifts in plant-feeding insects have been instrumental in generating the enormous diversity of insects. Changes in host use can cause host-associated differentiation (HAD) among populations that may lead to reproductive isolation and eventual speciation. The importance of geography in facilitating this process remains controversial. We examined the geographic context of HAD in the wide-ranging generalist yucca moth Prodoxus decipiens. Previous work demonstrated HAD among sympatric moth populations feeding on two different Yucca species occurring on the barrier islands of North Carolina, USA. We assessed the genetic structure of P. decipiens across its entire geographic and host range to determine whether HAD is widespread in this generalist herbivore. Population genetic analyses of microsatellite and mtDNA sequence data across the entire range showed genetic structuring with respect to host use and geography. In particular, genetic differentiation was relatively strong between mainland populations and those on the barrier islands of North Carolina. Finer scale analyses, however, among sympatric populations using different host plant species only showed significant clustering based on host use for populations on the barrier islands. Mainland populations did not form population clusters based on host plant use. Reduced genetic diversity in the barrier island populations, especially on the derived host, suggests that founder effects may have been instrumental in facilitating HAD. In general, results suggest that the interplay of local adaptation, geography and demography can determine the tempo of HAD. We argue that future studies should include comprehensive surveys across a wide range of environmental and geographic conditions to elucidate the contribution of various processes to HAD. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Small bite, large impact-saliva and salivary molecules in the medicinal leech, Hirudo medicinalis

NASA Astrophysics Data System (ADS)

Hildebrandt, Jan-Peter; Lemke, Sarah

2011-12-01

Blood-sucking leeches have been used for medical purposes in humans for hundreds of years. Accordingly, one of the most prominent species has been named Hirudo medicinalis by Carl Linne in 1758. Feeding on vertebrate blood poses some serious problems to blood-sucking ectoparasites, as they have to penetrate the body surface of the host and to suppress the normal reactions of the host to such injuries (swelling, pain, inflammation) to remain undetected during the feeding period. Furthermore, the parasites have to take measures to inhibit the normal reactions in host tissues to blood vessel damage, namely hemostasis and blood coagulation (platelet aggregation and activation, activation of thrombin and formation of fibrin clots). During evolution, leeches have acquired the ability to control these processes in their hosts by transferring various bioactive substances to the host. These substances are supposedly produced in unicellular salivary gland cells and injected into the wound at the feeding site through tiny salivary ductule openings in the jaws that the leech uses to slice open the host body surface and to cut blood vessels in the depth of the wound. This review summarizes current knowledge about the salivary gland cells and the biological effects of individual saliva components as well as hints to the potential usefulness of some of these compounds for medical purposes.

Phonon Softening due to Melting of the Ferromagnetic Order in Elemental Iron

NASA Astrophysics Data System (ADS)

Han, Qiang; Birol, Turan; Haule, Kristjan

2018-05-01

We study the fundamental question of the lattice dynamics of a metallic ferromagnet in the regime where the static long-range magnetic order is replaced by the fluctuating local moments embedded in a metallic host. We use the ab initio density functional theory + embedded dynamical mean-field theory functional approach to address the dynamic stability of iron polymorphs and the phonon softening with an increased temperature. We show that the nonharmonic and inhomogeneous phonon softening measured in iron is a result of the melting of the long-range ferromagnetic order and is unrelated to the first-order structural transition from the bcc to the fcc phase, as is usually assumed. We predict that the bcc structure is dynamically stable at all temperatures at normal pressure and is thermodynamically unstable only between the bcc-α and the bcc-δ phases of iron.

Parasitism genes and host range disparities in biotrophic nematodes: the conundrum of polyphagy versus specialisation.

PubMed

Blok, Vivian C; Jones, John T; Phillips, Mark S; Trudgill, David L

2008-03-01

This essay considers biotrophic cyst and root-knot nematodes in relation to their biology, host-parasite interactions and molecular genetics. These nematodes have to face the biological consequences of the physical constraints imposed by the soil environment in which they live while their hosts inhabit both above and below ground environments. The two groups of nematodes appear to have adopted radically different solutions to these problems with the result that one group is a host specialist and reproduces sexually while the other has an enormous host range and reproduces by mitotic parthenogenesis. We consider what is known about the modes of parasitism used by these nematodes and how it relates to their host range, including the surprising finding that parasitism genes in both nematode groups have been recruited from bacteria. The nuclear and mitochondrial genomes of these two nematode groups are very different and we consider how these findings relate to the biology of the organisms.

Spread of butternut canker in North America, host range, evidence of resistance within butternut populations and conservation genetics

Treesearch

M. E. Ostry; K. Woeste

2004-01-01

Butternut canker is killing trees throughout the range of butternut in North America and is threatening the viability of many populations in several areas. Although butternut is the primary host, other Juglans species and some hardwood species also are potential hosts. Evidence is building that genetic resistance within butternut populations may be...

Molecular and Morphological Analysis Reveals Five New Species of Zygophiala Associated with Flyspeck Signs on Plant Hosts from China

PubMed Central

Gao, Liu; Zhang, Mian; Zhao, Wanyu; Hao, Lu; Chen, Hongcai; Zhang, Rong; Batzer, Jean C.; Gleason, Mark L.; Sun, Guangyu

2014-01-01

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. PMID:25329930

A review of neosporosis and pathologic findings of Neospora caninum infection in wildlife

PubMed Central

Donahoe, Shannon L.; Lindsay, Scott A.; Krockenberger, Mark; Phalen, David; Šlapeta, Jan

2015-01-01

Neospora caninum is an apicomplexan parasite that is the etiologic agent of neosporosis, a devastating infectious disease regarded as a major cause of reproductive loss in cattle and neuromuscular disease in dogs worldwide. This protozoan pathogen is maintained in the environment by a heteroxenous life cycle that involves a definitive canid host and a wide range of intermediate hosts. In recent years, a number of wildlife species have been investigated for their possible involvement in the N. caninum life cycle and many have been implicated as intermediate hosts. However, in many instances these studies have utilized serological and molecular techniques to detect infection in clinically normal animals, and investigation of possible associated morbidity, mortality, and pathology has been neglected. As such, the occurrence and importance of Neospora-associated disease in wildlife species are unknown. In order to improve our understanding of the significance of N. caninum infection in nondomestic species, the present review provides an up-to-date summary of clinical neosporosis and N. caninum-associated pathologic lesions in naturally and experimentally infected wildlife species. We provide a list of all free-ranging and captive wildlife species identified with N. caninum infection to date using currently available diagnostic tools. The advantages and disadvantages of diagnostic methods in wildlife are addressed in order to recommend optimal diagnosis of confirming N. caninum infection and neosporosis in nondomestic species. Although current data would suggest that N. caninum infection does not adversely impact wildlife populations, there is a need for greater international uniformity in the diagnosis of N. caninum infection and neosporosis in nondomestic species in order to assess the true consequences of parasite infection. PMID:25973393

Revisiting Trypanosoma rangeli Transmission Involving Susceptible and Non-Susceptible Hosts

PubMed Central

Ferreira, Luciana de Lima; Pereira, Marcos Horácio; Guarneri, Alessandra Aparecida

2015-01-01

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. PMID:26469403

Introduction for Diffusion Chamber Culture Symposium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carsten, A. L.

The diffusion-chamber system has been applied to studies of cell kinetics, progenitor cell quantitation, humoral effects, immunological effects, cytogenetics, organogenesis, and the cellular effects of drugs and physical factors such as radiation, hypoxia, etc. Chamber contents have been analyzed by clot dissolution with measuring of cell content, limiting dilution evaluation, radionuclide utilization (tritiated thymidine labeling), growth of colony number, size and type, CFU-S or CFU-C content, or proliferation by secondary culture in mice or in vitro systems, and chromosome changes. Cell types ranging from embryonal tissues to adult normal and neoplastic tissues have been grown in hosts across species barriers.more » Advantages and disadvantages of this system are discussed.« less

Impact of Vector Dispersal and Host-Plant Fidelity on the Dissemination of an Emerging Plant Pathogen

PubMed Central

Johannesen, Jes; Foissac, Xavier; Kehrli, Patrik; Maixner, Michael

2012-01-01

Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a) and its vector (Hyalesthes obsoletus: Cixiidae) affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vectors widening their host-plant use from field bindweed to stinging nettle, and subsequent host specialisation. We found evidence for common origins of pathogen and vector south of the European Alps. Genetic patterns in vector populations show signals of secondary range expansion in Western Europe leading to dissemination of tuf-a pathogens, which might be newly acquired and of hybrid origin. Hence, the emergence of stolbur tuf-a in the northern range was explained by secondary immigration of vectors carrying stinging nettle-specialised tuf-a, not by widening the host-plant spectrum of resident vectors with pathogen transmission from field bindweed to stinging nettle nor by primary co-migration from the resident vector's historical area of origin. The introduction of tuf-a to stinging nettle in the northern range was therefore independent of vector's host-plant specialisation but the rapid pathogen dissemination depended on the vector's host shift, whereas the general dissemination elsewhere was linked to plant specialisation of the pathogen but not of the vector. PMID:23284774

Impact of vector dispersal and host-plant fidelity on the dissemination of an emerging plant pathogen.

PubMed

Johannesen, Jes; Foissac, Xavier; Kehrli, Patrik; Maixner, Michael

2012-01-01

Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a) and its vector (Hyalesthes obsoletus: Cixiidae) affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vectors widening their host-plant use from field bindweed to stinging nettle, and subsequent host specialisation. We found evidence for common origins of pathogen and vector south of the European Alps. Genetic patterns in vector populations show signals of secondary range expansion in Western Europe leading to dissemination of tuf-a pathogens, which might be newly acquired and of hybrid origin. Hence, the emergence of stolbur tuf-a in the northern range was explained by secondary immigration of vectors carrying stinging nettle-specialised tuf-a, not by widening the host-plant spectrum of resident vectors with pathogen transmission from field bindweed to stinging nettle nor by primary co-migration from the resident vector's historical area of origin. The introduction of tuf-a to stinging nettle in the northern range was therefore independent of vector's host-plant specialisation but the rapid pathogen dissemination depended on the vector's host shift, whereas the general dissemination elsewhere was linked to plant specialisation of the pathogen but not of the vector.

Some Growth Aspects of Seymeria cassioicies

Treesearch

Charles M. Stangle; Lytton J. Musselman

1981-01-01

The root parasite, Seymeria cassioides, will not initiate height growth without attachment to a host root when grown under normal fertility conditions, although the seedling may remain alive for 40 days or more without a host. During this time the roots elongate markedly. Fresh pine root segments do not influence the direction of root growth. Although S....

Neocortical Transplants in the Mammalian Brain Lack a Blood-Brain Barrier to Macromolecules

NASA Astrophysics Data System (ADS)

Rosenstein, Jeffrey M.

1987-02-01

In order to determine whether the blood-brain barrier was present in transplants of central nervous tissue, fetal neocortex, which already possesses blood-brain and blood-cerebrospinal fluid barriers to protein, was grafted into the undamaged fourth ventricle or directly into the neocortex of recipient rats. Horseradish peroxidase or a conjugated human immunoglobulin G-peroxidase molecule was systemically administered into the host. These proteins were detected within the cortical transplants within 2 minutes regardless of the age of the donor or postoperative time. At later times these compounds, which normally do not cross the blood-brain barrier, inundated the grafts and adjacent host brain and also entered the cerebrospinal fluid. Endogenous serum albumin detected immunocytochemically in untreated hosts had a comparable although less extensive distribution. Thus, transplants of fetal central nervous tissue have permanent barrier dysfunction, probably due to microvascular changes, and are not integrated physiologically within the host. Blood-borne compounds, either systemically administered or naturally occurring, which should never contact normal brain tissue, have direct access to these transplants and might affect neuronal function.

The Intestinal Microbiome and Health

PubMed Central

Tuddenham, Susan; Sears, Cynthia L.

2015-01-01

Purpose of Review A diverse array of microbes colonizes the human intestine. In this review we seek to outline the current state of knowledge on what characterizes a “healthy” or “normal” intestinal microbiome, what factors modify the intestinal microbiome in the healthy state and how the intestinal microbiome affects normal host physiology Recent Findings What constitutes a “normal” or “healthy” intestinal microbiome is an area of active research, but key characteristics may include diversity, richness and a microbial community’s resilience and ability to resist change. A number of factors, including age, the host immune system, host genetics, diet and antibiotic use appear to modify the intestinal microbiome in the normal state. New research shows that the microbiome likely plays a critical role in the healthy human immune system and metabolism. Summary It is clear that there is a complicated bi-directional relationship between the intestinal microbiota and host which is vital to health. An enhanced understanding of this relationship will be critical not only to maximize and maintain human health but also to shape our understanding of disease and to foster new therapeutic approaches. PMID:26237547

Host compatibility rather than vector–host-encounter rate determines the host range of avian Plasmodium parasites

PubMed Central

Medeiros, Matthew C. I.; Hamer, Gabriel L.; Ricklefs, Robert E.

2013-01-01

Blood-feeding arthropod vectors are responsible for transmitting many parasites between vertebrate hosts. While arthropod vectors often feed on limited subsets of potential host species, little is known about the extent to which this influences the distribution of vector-borne parasites in some systems. Here, we test the hypothesis that different vector species structure parasite–host relationships by restricting access of certain parasites to a subset of available hosts. Specifically, we investigate how the feeding patterns of Culex mosquito vectors relate to distributions of avian malaria parasites among hosts in suburban Chicago, IL, USA. We show that Plasmodium lineages, defined by cytochrome b haplotypes, are heterogeneously distributed across avian hosts. However, the feeding patterns of the dominant vectors (Culex restuans and Culex pipiens) are similar across these hosts, and do not explain the distributions of Plasmodium parasites. Phylogenetic similarity of avian hosts predicts similarity in their Plasmodium parasites. This effect was driven primarily by the general association of Plasmodium parasites with particular host superfamilies. Our results suggest that a mosquito-imposed encounter rate does not limit the distribution of avian Plasmodium parasites across hosts. This implies that compatibility between parasites and their avian hosts structure Plasmodium host range. PMID:23595266

Comparison of field-collected ascovirus isolates by DNA hybridization, host range, and histopathology.

PubMed

Hamm, J J; Styer, E L; Federici, B A

1998-09-01

Six field-collected ascovirus isolates obtained from five noctuid species in the continental United States were compared with respect to the general relatedness of their DNA, host range, and histopathology. Two isolates were from Spodoptera frugiperda, and the other four were from Autographa precationis, Heliothis virescens, Helicoverpa zea, and Trichoplusia ni. DNA-DNA hybridization studies showed that the six isolates belonged to three distinct viral species, with the isolates from S. frugiperda composing one species, those from A. precationis and H. virescens a second species, and those from H. zea and T. ni a third species. The host range and histopathology of each isolate was studied in eight noctuid species, S. frugiperda, Spodoptera ornithogalli, Spodoptera exigua, Spodoptera eridania, H. virescens, H. zea, A. precationis, and Feltia subterranea. Though some variation existed between the different isolates of each viral species, distinct patterns were apparent for each. The viral species from S. frugiperda had a host range that was limited primarily to Spodoptera species and both isolates of this virus only replicated and caused significant pathology in the fat body, whereas the viral species from A. precationis and H. virescens had a much broader host range that included most of the species tested, but also had a tissue tropism primarily restricted to the fat body. The viral species from T. ni and H. zea readily infected all the hosts tested, where the principal site of replication and significant pathology was the epidermis. In many test hosts, however, this viral species also replicated and caused significant pathology in the tracheal epithelium and to a lesser extent in the fat body. Aside from contributing to knowledge of ascovirus biology, these studies indicate that DNA hybridization profiles combined with studies of host range and tissue tropism can be used as characters for defining ascovirus species. Copyright 1998 Academic Press.

Charting the Course for Civil Affairs in the New Normal

DTIC Science & Technology

2015-07-01

Select a caveat Unlimited distribution Charting the Course for Civil Affairs in the New Normal Vera Zakem and Emily Mushen July...11  Challenges for Joint CA in the New Normal Environment ............................................ 13  New requirements for ...deliver essential services in preparation for handing full control back to the host nation government. Other independent civil affairs teams worked

Metabolism links bacterial biofilms and colon carcinogenesis

PubMed Central

Johnson, Caroline H.; Dejea, Christine M.; Edler, David; Hoang, Linh T.; Santidrian, Antonio F.; Felding, Brunhilde H.; Cho, Kevin; Wick, Elizabeth C.; Hechenbleikner, Elizabeth M.; Uritboonthai, Winnie; Goetz, Laura; Casero, Robert A.; Pardoll, Drew M.; White, James R.; Patti, Gary J.; Sears, Cynthia L.; Siuzdak, Gary

2015-01-01

SUMMARY Bacterial biofilms in the colon alter the host tissue microenvironment. A role for biofilms in colon cancer metabolism has been suggested but to date has not been evaluated. Using metabolomics, we investigated the metabolic influence that microbial biofilms have on colon tissues and the related occurrence of cancer. Patient-matched colon cancers and histologically normal tissues, with or without biofilms, were examined. We show the upregulation of polyamine metabolites in tissues from cancer hosts with significant enhancement of N1, N12-diacetylspermine in both biofilm positive cancer and normal tissues. Antibiotic treatment, which cleared biofilms, decreased N1, N12-diacetylspermine levels to those seen in biofilm negative tissues, indicating that host cancer and bacterial biofilm structures contribute to the polyamine metabolite pool. These results show that colonic mucosal biofilms alter the cancer metabolome, to produce a regulator of cellular proliferation and colon cancer growth potentially affecting cancer development and progression. PMID:25959674

Metabolism links bacterial biofilms and colon carcinogenesis.

PubMed

Johnson, Caroline H; Dejea, Christine M; Edler, David; Hoang, Linh T; Santidrian, Antonio F; Felding, Brunhilde H; Ivanisevic, Julijana; Cho, Kevin; Wick, Elizabeth C; Hechenbleikner, Elizabeth M; Uritboonthai, Winnie; Goetz, Laura; Casero, Robert A; Pardoll, Drew M; White, James R; Patti, Gary J; Sears, Cynthia L; Siuzdak, Gary

2015-06-02

Bacterial biofilms in the colon alter the host tissue microenvironment. A role for biofilms in colon cancer metabolism has been suggested but to date has not been evaluated. Using metabolomics, we investigated the metabolic influence that microbial biofilms have on colon tissues and the related occurrence of cancer. Patient-matched colon cancers and histologically normal tissues, with or without biofilms, were examined. We show the upregulation of polyamine metabolites in tissues from cancer hosts with significant enhancement of N(1), N(12)-diacetylspermine in both biofilm-positive cancer and normal tissues. Antibiotic treatment, which cleared biofilms, decreased N(1), N(12)-diacetylspermine levels to those seen in biofilm-negative tissues, indicating that host cancer and bacterial biofilm structures contribute to the polyamine metabolite pool. These results show that colonic mucosal biofilms alter the cancer metabolome to produce a regulator of cellular proliferation and colon cancer growth potentially affecting cancer development and progression. Copyright © 2015 Elsevier Inc. All rights reserved.

The Production of lnterleukin-1 Receptor Antagonist by Human Bronchogenic Carcinoma

PubMed Central

Smith, Daniel R.; Kunkel, Steven L.; Standiford, Theodore J.; Chensue, Stephen W.; Rolfe, Mark W.; Orringer, Mark B.; Whyte, Richard I.; Burdick, Marie D.; Danforth, Jean M.; Gilbert, Andrew R.; Strieter, Robert M.

1993-01-01

Bronchogenic carcinoma displays an aggressive clinical course that may reflect a capacity to evade host defenses. We postulated that tumors may elaborate interleukin-1 receptor antagonist protein (IRAP) to escape host interleukin-1-dependent responses. Homogenates of human bronchogenic lung tumors demonstrated significant increases of IRAP compared with normal lung tissue controls (n = 48). There was no significant difference in interleukin-1 β levels between tumor and normal lung tissue. Immunohistochemical staining localized IRAP to tumor cells. Semiquantitative pathological analysis demonstrated a modest inflammatory cell infiltrate with qualitative differences between tumors of different histology. Western blot analysis of tumor homogenates demonstrated several molecular weight forms of IRAP. Finally, antigenic IRAP was detected in supernatants of the human bronchogenic carcinoma cell line (A549) maintained in vitro. These findings illustrate the capacity of bronchogenic tumors to produce and secrete IRAP that may be important in tumor evasion of host defenses. ImagesFigure 3Figure 4 PMID:8362978

Evolution of Compatibility Range in the Rice-Magnaporthe oryzae System: An Uneven Distribution of R Genes Between Rice Subspecies.

PubMed

Gallet, Romain; Fontaine, Colin; Bonnot, François; Milazzo, Joëlle; Tertois, Christophe; Adreit, Henri; Ravigné, Virginie; Fournier, Elisabeth; Tharreau, Didier

2016-04-01

Efficient strategies for limiting the impact of pathogens on crops require a good understanding of the factors underlying the evolution of compatibility range for the pathogens and host plants, i.e., the set of host genotypes that a particular pathogen genotype can infect and the set of pathogen genotypes that can infect a particular host genotype. Until now, little is known about the evolutionary and ecological factors driving compatibility ranges in systems implicating crop plants. We studied the evolution of host and pathogen compatibility ranges for rice blast disease, which is caused by the ascomycete Magnaporthe oryzae. We challenged 61 rice varieties from three rice subspecies with 31 strains of M. oryzae collected worldwide from all major known genetic groups. We determined the compatibility range of each plant variety and pathogen genotype and the severity of each plant-pathogen interaction. Compatibility ranges differed between rice subspecies, with the most resistant subspecies selecting for pathogens with broader compatibility ranges and the least resistant subspecies selecting for pathogens with narrower compatibility ranges. These results are consistent with a nested distribution of R genes between rice subspecies.

Host range, immunity and antigenic properties of lambdoid coliphage HK97.

PubMed

Dhillon, E K; Dhillon, T S; Lai, A N; Linn, S

1980-09-01

Temperate coliphage HK97 was isolated from pig dung. Although HK97 is antigenically unrelated to coliphage lambda, it has similar morphology, host range and immunity properties, and can recombine with it.

Chemical similarity between historical and novel host plants promotes range and host expansion of the mountain pine beetle in a naïve host ecosystem.

PubMed

Erbilgin, Nadir; Ma, Cary; Whitehouse, Caroline; Shan, Bin; Najar, Ahmed; Evenden, Maya

2014-02-01

Host plant secondary chemistry can have cascading impacts on host and range expansion of herbivorous insect populations. We investigated the role of host secondary compounds on pheromone production by the mountain pine beetle (Dendroctonus ponderosae) (MPB) and beetle attraction in response to a historical (lodgepole pine, Pinus contorta var. latifolia) and a novel (jack pine, Pinus banksiana) hosts, as pheromones regulate the host colonization process. Beetles emit the same pheromones from both hosts, but more trans-verbenol, the primary aggregation pheromone, was emitted by female beetles on the novel host. The phloem of the novel host contains more α-pinene, a secondary compound that is the precursor for trans-verbenol production in beetle, than the historical host. Beetle-induced emission of 3-carene, another secondary compound found in both hosts, was also higher from the novel host. Field tests showed that the addition of 3-carene to the pheromone mixture mimicking the aggregation pheromones produced from the two host species increased beetle capture. We conclude that chemical similarity between historical and novel hosts has facilitated host expansion of MPB in jack pine forests through the exploitation of common host secondary compounds for pheromone production and aggregation on the hosts. Furthermore, broods emerging from the novel host were larger in terms of body size. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

A Learning-Based Wrapper Method to Correct Systematic Errors in Automatic Image Segmentation: Consistently Improved Performance in Hippocampus, Cortex and Brain Segmentation

PubMed Central

Wang, Hongzhi; Das, Sandhitsu R.; Suh, Jung Wook; Altinay, Murat; Pluta, John; Craige, Caryne; Avants, Brian; Yushkevich, Paul A.

2011-01-01

We propose a simple but generally applicable approach to improving the accuracy of automatic image segmentation algorithms relative to manual segmentations. The approach is based on the hypothesis that a large fraction of the errors produced by automatic segmentation are systematic, i.e., occur consistently from subject to subject, and serves as a wrapper method around a given host segmentation method. The wrapper method attempts to learn the intensity, spatial and contextual patterns associated with systematic segmentation errors produced by the host method on training data for which manual segmentations are available. The method then attempts to correct such errors in segmentations produced by the host method on new images. One practical use of the proposed wrapper method is to adapt existing segmentation tools, without explicit modification, to imaging data and segmentation protocols that are different from those on which the tools were trained and tuned. An open-source implementation of the proposed wrapper method is provided, and can be applied to a wide range of image segmentation problems. The wrapper method is evaluated with four host brain MRI segmentation methods: hippocampus segmentation using FreeSurfer (Fischl et al., 2002); hippocampus segmentation using multi-atlas label fusion (Artaechevarria et al., 2009); brain extraction using BET (Smith, 2002); and brain tissue segmentation using FAST (Zhang et al., 2001). The wrapper method generates 72%, 14%, 29% and 21% fewer erroneously segmented voxels than the respective host segmentation methods. In the hippocampus segmentation experiment with multi-atlas label fusion as the host method, the average Dice overlap between reference segmentations and segmentations produced by the wrapper method is 0.908 for normal controls and 0.893 for patients with mild cognitive impairment. Average Dice overlaps of 0.964, 0.905 and 0.951 are obtained for brain extraction, white matter segmentation and gray matter segmentation, respectively. PMID:21237273

Gut Microbiota and IGF-1.

PubMed

Yan, Jing; Charles, Julia F

2018-04-01

Microbiota and their hosts have coevolved for millions of years. Microbiota are not only critical for optimal development of the host under normal physiological growth, but also important to ensure proper host development during nutrient scarcity or disease conditions. A large body of research has begun to detail the mechanism(s) of how microbiota cooperate with the host to maintain optimal health status. One crucial host pathway recently demonstrated to be modulated by microbiota is that of the growth factor insulin like growth factor 1 (IGF-1). Gut microbiota are capable of dynamically modulating circulating IGF-1 in the host, with the majority of data suggesting that microbiota induce host IGF-1 synthesis to influence growth. Microbiota-derived metabolites such as short chain fatty acids are sufficient to induce IGF-1. Whether microbiota induction of IGF-1 is mediated by the difference in growth hormone expression or the host sensitivity to growth hormone is still under investigation. This review summarizes the current data detailing the interaction between gut microbiota, IGF-1 and host development.

Transcriptome of an Armillaria root disease pathogen reveals candidate genes involved in host substrate utilization at the host­-pathogen interface

Treesearch

A. L. Ross-Davis; J. E. Stewart; J. W. Hanna; M.-S. Kim; B. J. Knaus; R. Cronn; H. Rai; B. A. Richardson; G. I. McDonald; N. B. Klopfenstein

2013-01-01

Armillaria species display diverse ecological roles ranging from beneficial saprobe to virulent pathogen. Armillaria solidipes (formerly A. ostoyae), a causal agent of Armillaria root disease, is a virulent primary pathogen with a broad host range of woody plants across the Northern Hemisphere. This white-rot pathogen grows between trees as rhizomorphs and attacks...

Which morphological characteristics are most influenced by the host matrix in downy mildews? A case study in Pseudoperonospora cubensis.

PubMed

Runge, Fabian; Ndambi, Beninweck; Thines, Marco

2012-01-01

Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and width of sporangia, as well as, with some reservations, their ratio, are the most suitable characteristics for species delimitation.

Which Morphological Characteristics Are Most Influenced by the Host Matrix in Downy Mildews? A Case Study in Pseudoperonospora cubensis

PubMed Central

Runge, Fabian; Ndambi, Beninweck; Thines, Marco

2012-01-01

Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and width of sporangia, as well as, with some reservations, their ratio, are the most suitable characteristics for species delimitation. PMID:23166582

Patterns of host specificity among the helminth parasite fauna of freshwater siluriforms: testing the biogeographical core parasite fauna hypothesis.

PubMed

Rosas-Valdez, Rogelio; de León, Gerardo Pérez-Ponce

2011-04-01

Host specificity plays an essential role in shaping the evolutionary history of host-parasite associations. In this study, an index of host specificity recently proposed was used to test, quantitatively, the hypothesis that some groups of parasites are characteristics of some host fish families along their distribution range. A database with all published records on the helminth parasites of freshwater siluriforms of Mexico was used. The host specificity index was used considering its advantage to measure the taxonomic heterogeneity of the host assemblages and its appropriateness for unequal sampling data. The helminth parasite fauna of freshwater siluriforms in Mexico seems to be specific for different host taxonomic categories. However, a relatively high number of species (47% of the total helminth fauna) is specific to their respective host family. This result provides further corroboration for the biogeographic hypothesis of the core helminth fauna proposed previously. The statistical values for host specificity obtained herein seem to be independent of host range. However, the accurate taxonomic identification of the parasites is fundamental for the evaluation of host specificity and the accurate evolutionary interpretation of this phenomenon.

Electrodeposited Ni nanowires-track etched P.E.T. composites as selective solar absorbers

NASA Astrophysics Data System (ADS)

Lukhwa, R.; Sone, B.; Kotsedi, L.; Madjoe, R.; Maaza, M.

2018-05-01

This contribution reports on the structural, optical and morphological properties of nanostructured flexible solar-thermal selective absorber composites for low temperature applications. The candidate material in the system is consisting of electrodeposited nickel nano-cylinders embedded in track-etched polyethylene terephthalate (PET) host membrane of pore sizes ranging between 0.3-0.8µm supported by conductive nickel thin film of about 0.5µm. PET were irradiated with 11MeV/u high charged xenon (Xe) ions at normal incidence. The tubular and metallic structure of the nickel nano-cylinders within the insulator polymeric host forms a typical ceramic-metal nano-composite "Cermet". The produced material was characterized by the following techniques: X-ray diffraction (XRD) for structural characterization to determine preferred crystallographic structure, and grain size of the materials; Scanning electron microscopy (SEM) to determine surface morphology, particle size, and visual imaging of distribution of structures on the surface of the substrate; Atomic force microscopy (AFM) to characterize surface roughness, surface morphology, and film thickness, and UV-Vis-NIR spectrophotometer to measure the reflectance, then to determine solar absorption

Cost (non)-recovery by platform technology facilities in the Bio21 Cluster.

PubMed

Gibbs, Gerard; Clark, Stella; Quinn, Julieanne; Gleeson, Mary Joy

2010-04-01

Platform technologies (PT) are techniques or tools that enable a range of scientific investigations and are critical to today's advanced technology research environment. Once installed, they require specialized staff for their operations, who in turn, provide expertise to researchers in designing appropriate experiments. Through this pipeline, research outputs are raised to the benefit of the researcher and the host institution. Platform facilities provide access to instrumentation and expertise for a wide range of users beyond the host institution, including other academic and industry users. To maximize the return on these substantial public investments, this wider access needs to be supported. The question of support and the mechanisms through which this occurs need to be established based on a greater understanding of how PT facilities operate. This investigation was aimed at understanding if and how platform facilities across the Bio21 Cluster meet operating costs. Our investigation found: 74% of platforms surveyed do not recover 100% of direct operating costs and are heavily subsidized by their home institution, which has a vested interest in maintaining the technology platform; platform managers play a major role in establishing the costs and pricing of the facility, normally in a collaborative process with a management committee or institutional accountant; and most facilities have a three-tier pricing structure recognizing internal academic, external academic, and commercial clients.

Cost (Non)-Recovery by Platform Technology Facilities in the Bio21 Cluster

PubMed Central

Gibbs, Gerard; Clark, Stella; Quinn, JulieAnne; Gleeson, Mary Joy

2010-01-01

Platform technologies (PT) are techniques or tools that enable a range of scientific investigations and are critical to today's advanced technology research environment. Once installed, they require specialized staff for their operations, who in turn, provide expertise to researchers in designing appropriate experiments. Through this pipeline, research outputs are raised to the benefit of the researcher and the host institution.1 Platform facilities provide access to instrumentation and expertise for a wide range of users beyond the host institution, including other academic and industry users. To maximize the return on these substantial public investments, this wider access needs to be supported. The question of support and the mechanisms through which this occurs need to be established based on a greater understanding of how PT facilities operate. This investigation was aimed at understanding if and how platform facilities across the Bio21 Cluster meet operating costs. Our investigation found: 74% of platforms surveyed do not recover 100% of direct operating costs and are heavily subsidized by their home institution, which has a vested interest in maintaining the technology platform; platform managers play a major role in establishing the costs and pricing of the facility, normally in a collaborative process with a management committee or institutional accountant; and most facilities have a three-tier pricing structure recognizing internal academic, external academic, and commercial clients. PMID:20357980

Functional recovery of completely denervated muscle: implications for innervation of tissue-engineered muscle.

PubMed

Kang, Sung-Bum; Olson, Jennifer L; Atala, Anthony; Yoo, James J

2012-09-01

Tissue-engineered muscle has been proposed as a solution to repair volumetric muscle defects and to restore muscle function. To achieve functional recovery, engineered muscle tissue requires integration of the host nerve. In this study, we investigated whether denervated muscle, which is analogous to tissue-engineered muscle tissue, can be reinnervated and can recover muscle function using an in vivo model of denervation followed by neurotization. The outcomes of this investigation may provide insights on the ability of tissue-engineered muscle to integrate with the host nerve and acquire normal muscle function. Eighty Lewis rats were classified into three groups: a normal control group (n=16); a denervated group in which sciatic innervations to the gastrocnemius muscle were disrupted (n=32); and a transplantation group in which the denervated gastrocnemius was repaired with a common peroneal nerve graft into the muscle (n=32). Neurofunctional behavior, including extensor postural thrust (EPT), withdrawal reflex latency (WRL), and compound muscle action potential (CMAP), as well as histological evaluations using alpha-bungarotoxin and anti-NF-200 were performed at 2, 4, 8, and 12 weeks (n=8) after surgery. We found that EPT was improved by transplantation of the nerve grafts, but the EPT values in the transplanted animals at 12 weeks postsurgery were still significantly lower than those measured for the normal control group at 4 weeks (EPT, 155.0±38.9 vs. 26.3±13.8 g, p<0.001; WRL, 2.7±2.30 vs. 8.3±5.5 s, p=0.027). In addition, CMAP latency and amplitude significantly improved with time after surgery in the transplantation group (p<0.001, one-way analysis of variance), and at 12 weeks postsurgery, CMAP latency and amplitude were not statistically different from normal control values (latency, 0.9±0.0 vs. 1.3±0.7 ms, p=0.164; amplitude, 30.2±7.0 vs. 46.4±26.9 mV, p=0.184). Histologically, regeneration of neuromuscular junctions was seen in the transplantation group. This study indicates that transplanted nerve tissue is able to regenerate neuromuscular junctions within denervated muscle, and thus the muscle can recover partial function. However, the function of the denervated muscle remains in the subnormal range even at 12 weeks after direct nerve transplantation. These results suggest that tissue-engineered muscle, which is similarly denervated, could be innervated and become functional in vivo if it is properly integrated with the host nerve.

Evasion and Immuno-Endocrine Regulation in Parasite Infection: Two Sides of the Same Coin in Chagas Disease?

PubMed

Morrot, Alexandre; Villar, Silvina R; González, Florencia B; Pérez, Ana R

2016-01-01

Chagas disease is a serious illness caused by the protozoan parasite Trypanosoma cruzi. Nearly 30% of chronically infected people develop cardiac, digestive, or mixed alterations, suggesting a broad range of host-parasite interactions that finally impact upon chronic disease outcome. The ability of T. cruzi to persist and cause pathology seems to depend on diverse factors like T. cruzi strains, the infective load and the route of infection, presence of virulence factors, the parasite capacity to avoid protective immune response, the strength and type of host defense mechanisms and the genetic background of the host. The host-parasite interaction is subject to a constant neuro-endocrine regulation that is thought to influence the adaptive immune system, and as the infection proceeds it can lead to a broad range of outcomes, ranging from pathogen elimination to its continued persistence in the host. In this context, T. cruzi evasion strategies and host defense mechanisms can be envisioned as two sides of the same coin, influencing parasite persistence and different outcomes observed in Chagas disease. Understanding how T. cruzi evade host's innate and adaptive immune response will provide important clues to better dissect mechanisms underlying the pathophysiology of Chagas disease.

Silage Collected from Dairy Farms Harbors an Abundance of Listeriaphages with Considerable Host Range and Genome Size Diversity

PubMed Central

Vongkamjan, Kitiya; Switt, Andrea Moreno; den Bakker, Henk C.; Fortes, Esther D.

2012-01-01

Since the food-borne pathogen Listeria monocytogenes is common in dairy farm environments, it is likely that phages infecting this bacterium (“listeriaphages”) are abundant on dairy farms. To better understand the ecology and diversity of listeriaphages on dairy farms and to develop a diverse phage collection for further studies, silage samples collected on two dairy farms were screened for L. monocytogenes and listeriaphages. While only 4.5% of silage samples tested positive for L. monocytogenes, 47.8% of samples were positive for listeriaphages, containing up to >1.5 × 104 PFU/g. Host range characterization of the 114 phage isolates obtained, with a reference set of 13 L. monocytogenes strains representing the nine major serotypes and four lineages, revealed considerable host range diversity; phage isolates were classified into nine lysis groups. While one serotype 3c strain was not lysed by any phage isolates, serotype 4 strains were highly susceptible to phages and were lysed by 63.2 to 88.6% of phages tested. Overall, 12.3% of phage isolates showed a narrow host range (lysing 1 to 5 strains), while 28.9% of phages represented broad host range (lysing ≥11 strains). Genome sizes of the phage isolates were estimated to range from approximately 26 to 140 kb. The extensive host range and genomic diversity of phages observed here suggest an important role of phages in the ecology of L. monocytogenes on dairy farms. In addition, the phage collection developed here has the potential to facilitate further development of phage-based biocontrol strategies (e.g., in silage) and other phage-based tools. PMID:23042180

Living on the Edge: Parasite Prevalence Changes Dramatically across a Range Edge in an Invasive Gecko.

PubMed

Coates, Andrew; Barnett, Louise K; Hoskin, Conrad; Phillips, Ben L

2017-02-01

Species interactions can determine range limits, and parasitism is the most intimate of such interactions. Intriguingly, the very conditions on range edges likely change host-parasite dynamics in nontrivial ways. Range edges are often associated with clines in host density and with environmental transitions, both of which may affect parasite transmission. On advancing range edges, founder events and fitness/dispersal costs of parasitism may also cause parasites to be lost on range edges. Here we examine the prevalence of three species of parasite across the range edge of an invasive gecko, Hemidactylus frenatus, in northeastern Australia. The gecko's range edge spans the urban-woodland interface at the edge of urban areas. Across this edge, gecko abundance shows a steep decline, being lower in the woodland. Two parasite species (a mite and a pentastome) are coevolved with H. frenatus, and these species become less prevalent as the geckos become less abundant. A third species of parasite (another pentastome) is native to Australia and has no coevolutionary history with H. frenatus. This species became more prevalent as the geckos become less abundant. These dramatic shifts in parasitism (occurring over 3.5 km) confirm that host-parasite dynamics can vary substantially across the range edge of this gecko host.

Short-sighted evolution of virulence in parasitic honeybee workers ( Apis mellifera capensis Esch.)

NASA Astrophysics Data System (ADS)

Moritz, Robin F. A.; Pirk, Christian W. W.; Hepburn, H. Randall; Neumann, Peter

2008-06-01

The short-sighted selection hypothesis for parasite virulence predicts that winners of within-host competition are poorer at transmission to new hosts. Social parasitism by self-replicating, female-producing workers occurs in the Cape honeybee Apis mellifera capensis, and colonies of other honeybee subspecies are susceptible hosts. We found high within-host virulence but low transmission rates in a clone of social parasitic A. m. capensis workers invading the neighbouring subspecies A. m. scutellata. In contrast, parasitic workers from the endemic range of A. m. capensis showed low within-host virulence but high transmission rates. This suggests a short-sighted selection scenario for the host-parasite co-evolution in the invasive range of the Cape honeybee, probably facilitated by beekeeping-assisted parasite transmission in apiaries.

Subhalo demographics in the Illustris simulation: effects of baryons and halo-to-halo variation

NASA Astrophysics Data System (ADS)

Chua, Kun Ting Eddie; Pillepich, Annalisa; Rodriguez-Gomez, Vicente; Vogelsberger, Mark; Bird, Simeon; Hernquist, Lars

2017-12-01

We study the abundance of subhaloes in the hydrodynamical cosmological simulation Illustris, which includes both baryons and dark matter in a cold dark matter volume 106.5 Mpc a side. We compare Illustris to its dark-matter only (DMO) analogue, Illustris-Dark and quantify the effects of baryonic processes on the demographics of subhaloes in the host mass range 1011-3 × 1014 M⊙. We focus on both the evolved (z = 0) subhalo cumulative mass functions (SHMF) and the statistics of subhaloes ever accreted, i.e. infall SHMF. We quantify the variance in subhalo abundance at fixed host mass and investigate the physical reasons responsible for such scatter. We find that in Illustris, baryonic physics impacts both the infall and z = 0 subhalo abundance by tilting the DMO function and suppressing the abundance of low-mass subhaloes. The breaking of self-similarity in the subhalo abundance at z = 0 is enhanced by the inclusion of baryonic physics. The non-monotonic alteration of the evolved subhalo abundances can be explained by the modification of the concentration-mass relation of Illustris hosts compared to Illustris-Dark. Interestingly, the baryonic implementation in Illustris does not lead to an increase in the halo-to-halo variation compared to Illustris-Dark. In both cases, the normalized intrinsic scatter today is larger for Milky Way-like haloes than for cluster-sized objects. For Milky Way-like haloes, it increases from about eight per cent at infall to about 25 per cent at the current epoch. In both runs, haloes of fixed mass formed later host more subhaloes than early formers.

Are beryllium abundances anomalous in stars with giant planets?

NASA Astrophysics Data System (ADS)

Santos, N. C.; Israelian, G.; García López, R. J.; Mayor, M.; Rebolo, R.; Randich, S.; Ecuvillon, A.; Domínguez Cerdeña, C.

2004-12-01

In this paper we present beryllium (Be) abundances in a large sample of 41 extra-solar planet host stars, and for 29 stars without any known planetary-mass companion, spanning a large range of effective temperatures. The Be abundances were derived through spectral synthesis done in standard Local Thermodynamic Equilibrium, using spectra obtained with various instruments. The results seem to confirm that overall, planet-host stars have ``normal'' Be abundances, although a small, but not significant, difference might be present. This result is discussed, and we show that this difference is probably not due to any stellar ``pollution'' events. In other words, our results support the idea that the high-metal content of planet-host stars has, overall, a ``primordial'' origin. However, we also find a small subset of planet-host late-F and early-G dwarfs that might have higher than average Be abundances. The reason for the offset is not clear, and might be related either to the engulfment of planetary material, to galactic chemical evolution effects, or to stellar-mass differences for stars of similar temperature. Based on observations collected with the VLT/UT2 Kueyen telescope (Paranal Observatory, ESO, Chile) using the UVES spectrograph (Observing runs 66.C-0116 A, 66.D-0284 A, and 68.C-0058 A), and with the William Herschel and Nordic Optical Telescopes, operated on the island of La Palma by the Isaac Newton Group and jointly by Denmark, Finland, Iceland, and Norway, respectively, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

Chemical and behavioral integration of army ant-associated rove beetles - a comparison between specialists and generalists.

PubMed

von Beeren, Christoph; Brückner, Adrian; Maruyama, Munetoshi; Burke, Griffin; Wieschollek, Jana; Kronauer, Daniel J C

2018-01-01

Host-symbiont interactions are embedded in ecological communities and range from unspecific to highly specific relationships. Army ants and their arthropod guests represent a fascinating example of species-rich host-symbiont associations where host specificity ranges across the entire generalist - specialist continuum. In the present study, we compared the behavioral and chemical integration mechanisms of two extremes of the generalist - specialist continuum: generalist ant-predators in the genus Tetradonia (Staphylinidae: Aleocharinae: Athetini), and specialist ant-mimics in the genera Ecitomorpha and Ecitophya (Staphylinidae: Aleocharinae: Ecitocharini). Similar to a previous study of Tetradonia beetles, we combined DNA barcoding with morphological studies to define species boundaries in ant-mimicking beetles. This approach found four ant-mimicking species at our study site at La Selva Biological Station in Costa Rica. Community sampling of Eciton army ant parasites revealed that ant-mimicking beetles were perfect host specialists, each beetle species being associated with a single Eciton species. These specialists were seamlessly integrated into the host colony, while generalists avoided physical contact to host ants in behavioral assays. Analysis of the ants' nestmate recognition cues, i.e. cuticular hydrocarbons (CHCs), showed close similarity in CHC composition and CHC concentration between specialists and Eciton burchellii foreli host ants. On the contrary, the chemical profiles of generalists matched host profiles less well, indicating that high accuracy in chemical host resemblance is only accomplished by socially integrated species. Considering the interplay between behavior, morphology, and cuticular chemistry, specialists but not generalists have cracked the ants' social code with respect to various sensory modalities. Our results support the long-standing idea that the evolution of host-specialization in parasites is a trade-off between the range of potential host species and the level of specialization on any particular host.

Effects of dietary antibiotic growth promoters on various aspects of host responses to Necrotic enteritis in broiler chickens

USDA-ARS?s Scientific Manuscript database

There is an increased interest in restricting the use of antibiotic growth promoters (AGPs) in animal agriculture. In order to better understand the mechanisms of AGPs in poultry, we carried out series of in vivo studies to investigate various aspects of host responses to AGPs in normal and necroti...

Developmental thyroid hormone insufficiency and brain development: A role for brain-derived neurotrophic factor (BDNF)?*

EPA Science Inventory

Thyroid hormones (TH) are essential for normal brain development. Even subclinical hypothyroidism experienced in utero can result in neuropsychological deficits in children despite normal thyroid status at birth. Neurotrophins have been implicated in a host of brain cellular func...

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

PubMed Central

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

Pre-eruptive processes and timescales recorded in olivine crystals and melt inclusions from the 2007 caldera-forming eruption of Piton de la Fournaise (La Réunion Island)

NASA Astrophysics Data System (ADS)

Albert, H.; Costa Rodriguez, F.; Herrin, J. S.; Di Muro, A.; Metrich, N.

2017-12-01

Summit caldera collapse is a rare event at Piton de la Fournaise. One such event occurred in 2007 during one of the largest historic eruptions of more than 200 Mm3 of magma. Effusion of aphyric basalts initiated at the summit area in mid-February, followed by the migration of active vents in March and early April to progressively lower elevations. Collapse of a 1 km diameter summit caldera occurred on April 5th while effusion of crystal rich lava continued until May 1st. Here we investigate these events through timescales recorded in olivine crystals and their melt inclusions (MIs) using a diffusion modelling approach. Olivine crystals from the early tephra emitted just before caldera collapse and from the post caldera collapse lava display similar compositions and zoning patterns. Fo [%Fo=100*Mg/(Mg+Fe)] values range from ≈82 to ≈86 and the phenocrysts are complexly zoned including a reverse followed by normal zoning. Fo≈84 cores are surrounded by a Fo≈86 plateau. In contact with the surrounding matrix or MIs, crystals exhibit normal zoning toward values of Fo≈82-83. Phosphorus distribution revealed in 2D X-Ray maps shows complex patterns that can be interpreted as early skeletal growth likely responsible for entrapment of MIs. Diffusion modeling of Fo, Ca, and Ni reveals two distinct magma residence timescales recorded in olivine. The inner reversed-zoned profiles yield timescales of 1-2 years, while normally-zoned profiles at crystal rims and also adjacent to MIs yield timescales of only a few days. Modelling of the P zoning patterns is consistent with the 1-2 year timescales obtained from reversely-zoned profiles. H2O contents of olivine-hosted MIs range from 0.35-1.16 wt%. Selective loss of water in some MIs suggests diffusive re-equilibration between the MIs and host magma during ascent. We have applied H2O diffusion modeling to estimate timescales of water loss of a few days, consistent with the results of Fo/Ca/Ni modeling of olivine profiles. We infer that the timescales of one to two years obtained from reversely-zoned profiles and P in olivine could record residence in a long-lived intrusive body sitting below the volcano summit which was fluidized during the eruption leading to caldera collapse. Timescales of one to a few days obtained from normal zoning and water loss record magma ascent during the 2007 eruption.

Prevalence, Genetic Characterization, and 18S Small Subunit Ribosomal RNA Diversity of Trypanosoma rangeli in Triatomine and Mammal Hosts in Endemic Areas for Chagas Disease in Ecuador

PubMed Central

Ocaña-Mayorga, Sofia; Aguirre-Villacis, Fernanda; Pinto, C. Miguel; Vallejo, Gustavo A.

2015-01-01

Abstract Trypanosoma rangeli is a nonpathogenic parasite for humans; however, its medical importance relies in its similarity and overlapping distribution with Trypanosoma cruzi, causal agent of Chagas disease in the Americas. The genetic diversity of T. rangeli and its association with host species (triatomines and mammals) has been identified along Central and the South America; however, it has not included data of isolates from Ecuador. This study reports infection with T. rangeli in 18 genera of mammal hosts and five species of triatomines in three environments (domestic, peridomestic, and sylvatic). Higher infection rates were found in the sylvatic environment, in close association with Rhodnius ecuadoriensis. The results of this study extend the range of hosts infected with this parasite and the geographic range of the T. rangeli genotype KP1(−)/lineage C in South America. It was not possible to detect variation on T. rangeli from the central coastal region and southern Ecuador with the analysis of the small subunit ribosomal RNA (SSU-rRNA) gene, even though these areas are ecologically different and a phenotypic subdivision of R. ecuadoriensis has been found. R. ecuadoriensis is considered one of the most important vectors for Chagas disease transmission in Ecuador due to its wide distribution and adaptability to diverse environments. An extensive knowledge of the trypanosomes circulating in this species of triatomine, and associated mammal hosts, is important for delineating transmission dynamics and preventive measures in the endemic areas of Ecuador and Northern Peru. PMID:26645579

Prevalence, Genetic Characterization, and 18S Small Subunit Ribosomal RNA Diversity of Trypanosoma rangeli in Triatomine and Mammal Hosts in Endemic Areas for Chagas Disease in Ecuador.

PubMed

Ocaña-Mayorga, Sofia; Aguirre-Villacis, Fernanda; Pinto, C Miguel; Vallejo, Gustavo A; Grijalva, Mario J

2015-12-01

Trypanosoma rangeli is a nonpathogenic parasite for humans; however, its medical importance relies in its similarity and overlapping distribution with Trypanosoma cruzi, causal agent of Chagas disease in the Americas. The genetic diversity of T. rangeli and its association with host species (triatomines and mammals) has been identified along Central and the South America; however, it has not included data of isolates from Ecuador. This study reports infection with T. rangeli in 18 genera of mammal hosts and five species of triatomines in three environments (domestic, peridomestic, and sylvatic). Higher infection rates were found in the sylvatic environment, in close association with Rhodnius ecuadoriensis. The results of this study extend the range of hosts infected with this parasite and the geographic range of the T. rangeli genotype KP1(-)/lineage C in South America. It was not possible to detect variation on T. rangeli from the central coastal region and southern Ecuador with the analysis of the small subunit ribosomal RNA (SSU-rRNA) gene, even though these areas are ecologically different and a phenotypic subdivision of R. ecuadoriensis has been found. R. ecuadoriensis is considered one of the most important vectors for Chagas disease transmission in Ecuador due to its wide distribution and adaptability to diverse environments. An extensive knowledge of the trypanosomes circulating in this species of triatomine, and associated mammal hosts, is important for delineating transmission dynamics and preventive measures in the endemic areas of Ecuador and Northern Peru.

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

PubMed

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.

Benefits of fidelity: does host specialization impact nematode parasite life history and fecundity?

PubMed

Koprivnikar, J; Randhawa, H S

2013-04-01

The range of hosts used by a parasite is influenced by macro-evolutionary processes (host switching, host-parasite co-evolution), as well as 'encounter filters' and 'compatibility filters' at the micro-evolutionary level driven by host/parasite ecology and physiology. Host specialization is hypothesized to result in trade-offs with aspects of parasite life history (e.g. reproductive output), but these have not been well studied. We used previously published data to create models examining general relationships among host specificity and important aspects of life history and reproduction for nematodes parasitizing animals. Our results indicate no general trade-off between host specificity and the average pre-patent period (time to first reproduction), female size, egg size, or fecundity of these nematodes. However, female size was positively related to egg size, fecundity, and pre-patent period. Host compatibility may thus not be the primary determinant of specificity in these parasitic nematodes if there are few apparent trade-offs with reproduction, but rather, the encounter opportunities for new host species at the micro-evolutionary level, and other processes at the macro-evolutionary level (i.e. phylogeny). Because host specificity is recognized as a key factor determining the spread of parasitic diseases understanding factors limiting host use are essential to predict future changes in parasite range and occurrence.

Phylogenetic relatedness and host plant growth form influence gene expression of the polyphagous comma butterfly (Polygonia c-album)

PubMed Central

Heidel-Fischer, Hanna M; Freitak, Dalial; Janz, Niklas; Söderlind, Lina; Vogel, Heiko; Nylin, Sören

2009-01-01

Background The mechanisms that shape the host plant range of herbivorous insect are to date not well understood but knowledge of these mechanisms and the selective forces that influence them can expand our understanding of the larger ecological interaction. Nevertheless, it is well established that chemical defenses of plants influence the host range of herbivorous insects. While host plant chemistry is influenced by phylogeny, also the growth forms of plants appear to influence the plant defense strategies as first postulated by Feeny (the "plant apparency" hypothesis). In the present study we aim to investigate the molecular basis of the diverse host plant range of the comma butterfly (Polygonia c-album) by testing differential gene expression in the caterpillars on three host plants that are either closely related or share the same growth form. Results In total 120 genes were identified to be differentially expressed in P. c-album after feeding on different host plants, 55 of them in the midgut and 65 in the restbody of the caterpillars. Expression patterns could be confirmed with an independent method for 14 of 27 tested genes. Pairwise similarities in upregulation in the midgut of the caterpillars were higher between plants that shared either growth form or were phylogenetically related. No known detoxifying enzymes were found to be differently regulated in the midgut after feeding on different host plants. Conclusion Our data suggest a complex picture of gene expression in response to host plant feeding. While each plant requires a unique gene regulation in the caterpillar, both phylogenetic relatedness and host plant growth form appear to influence the expression profile of the polyphagous comma butterfly, in agreement with phylogenetic studies of host plant utilization in butterflies. PMID:19878603

Phylogenetic relatedness and host plant growth form influence gene expression of the polyphagous comma butterfly (Polygonia c-album).

PubMed

Heidel-Fischer, Hanna M; Freitak, Dalial; Janz, Niklas; Söderlind, Lina; Vogel, Heiko; Nylin, Sören

2009-10-31

The mechanisms that shape the host plant range of herbivorous insect are to date not well understood but knowledge of these mechanisms and the selective forces that influence them can expand our understanding of the larger ecological interaction. Nevertheless, it is well established that chemical defenses of plants influence the host range of herbivorous insects. While host plant chemistry is influenced by phylogeny, also the growth forms of plants appear to influence the plant defense strategies as first postulated by Feeny (the "plant apparency" hypothesis). In the present study we aim to investigate the molecular basis of the diverse host plant range of the comma butterfly (Polygonia c-album) by testing differential gene expression in the caterpillars on three host plants that are either closely related or share the same growth form. In total 120 genes were identified to be differentially expressed in P. c-album after feeding on different host plants, 55 of them in the midgut and 65 in the restbody of the caterpillars. Expression patterns could be confirmed with an independent method for 14 of 27 tested genes. Pairwise similarities in upregulation in the midgut of the caterpillars were higher between plants that shared either growth form or were phylogenetically related. No known detoxifying enzymes were found to be differently regulated in the midgut after feeding on different host plants. Our data suggest a complex picture of gene expression in response to host plant feeding. While each plant requires a unique gene regulation in the caterpillar, both phylogenetic relatedness and host plant growth form appear to influence the expression profile of the polyphagous comma butterfly, in agreement with phylogenetic studies of host plant utilization in butterflies.

Evolution in action: climate change, biodiversity dynamics and emerging infectious disease

PubMed Central

Hoberg, Eric P.; Brooks, Daniel R.

2015-01-01

Climatological variation and ecological perturbation have been pervasive drivers of faunal assembly, structure and diversification for parasites and pathogens through recurrent events of geographical and host colonization at varying spatial and temporal scales of Earth history. Episodic shifts in climate and environmental settings, in conjunction with ecological mechanisms and host switching, are often critical determinants of parasite diversification, a view counter to more than a century of coevolutionary thinking about the nature of complex host–parasite assemblages. Parasites are resource specialists with restricted host ranges, yet shifts onto relatively unrelated hosts are common during phylogenetic diversification of parasite lineages and directly observable in real time. The emerging Stockholm Paradigm resolves this paradox: Ecological Fitting (EF)—phenotypic flexibility and phylogenetic conservatism in traits related to resource use, most notably host preference—provides many opportunities for rapid host switching in changing environments, without the evolution of novel host-utilization capabilities. Host shifts via EF fuel the expansion phase of the Oscillation Hypothesis of host range and speciation and, more generally, the generation of novel combinations of interacting species within the Geographic Mosaic Theory of Coevolution. In synergy, an environmental dynamic of Taxon Pulses establishes an episodic context for host and geographical colonization. PMID:25688014

Frequent conjugative transfer accelerates adaptation of a broad-host-range plasmid to an unfavorable Pseudomonas putida host.

PubMed

Heuer, Holger; Fox, Randal E; Top, Eva M

2007-03-01

IncP-1 plasmids are known to be promiscuous, but it is not understood if they are equally well adapted to various species within their host range. Moreover, little is known about their fate in bacterial communities. We determined if the IncP-1beta plasmid pB10 was unstable in some Proteobacteria, and whether plasmid stability was enhanced after long-term carriage in a single host and when regularly switched between isogenic hosts. Plasmid pB10 was found to be very unstable in Pseudomonas putida H2, and conferred a high cost (c. 20% decrease in fitness relative to the plasmid-free host). H2(pB10) was then evolved under conditions that selected for plasmid maintenance, with or without regular plasmid transfer (host-switching). When tested in the ancestral host, the evolved plasmids were more stable and their cost was significantly reduced (9% and 16% for plasmids from host-switched and nonswitched lineages, respectively). Our findings suggest that IncP-1 plasmids can rapidly adapt to an unfavorable host by improving their overall stability, and that regular conjugative transfer accelerates this process.

Celticecis, a Genus of Gall Midges (Diptera: Cecidomyiidae), Newly Reported for the Western Palearctic Region

Treesearch

Raymond J. Gagné; John C. Moser

1997-01-01

Many Holarctic genera of trees and shrubs are host over much of their ranges to particular genera of Cecidomyiidae. As examples, willows host gall midges of Rabdophaga and Iteomyia, oaks host Macrodiplosis and Polystepha, and birches host Semudobia in both the Nearctic and...

Identification of Mycobacterium avium subsp. hominissuis Isolated From Drinking Water

EPA Science Inventory

Mycobacterium avium (MA) is divided into four subspecies based primarily on host-range and consists of MA subsp. avium (birds), MA subsp. silvaticum (wood pigeons), MA subsp. paratuberculosis (broad, poorly-defined host range), and the recently described MA subsp. hominissuis (hu...

Transmission of Citrus leprosis virus C by Brevipalpus phoenicis (Geijskes) to Alternative Host Plants Found in Citrus Orchards

USDA-ARS?s Scientific Manuscript database

The equivalent of US$ 75 million is spent each year in Brazil to control Brevipalpus phoenicis, a mite vector of Citrus leprosis virus C (CiLV-C). In this study we investigated the possibility that hedgerows, windbreaks, and weeds normally found in citrus orchards could host CiLV-C. Mites reared on ...

Gnathostomiasis in a Wild-Caught Nine-Banded Armadillo (Dasypus Novemcinctus)

DTIC Science & Technology

1993-12-01

were below nal host. In addition, many paratenic hosts aid in transmis- normal limits. Peripheral circulation was poor. When the sion through predation ...debris. H&E stain. caused by the aberrant mi-,ttk,, or q l~rv.a form of this 120x. 631 \\ol 41:, No ki Laltmatoryv Aimal Sci,,ac 1),v,111 er 1 992

An antibiotic-altered microbiota provides fuel for the enteric foe.

PubMed

Stiemsma, Leah T; Turvey, Stuart E; Finlay, Brett B

2014-01-01

Antibiotic therapies disrupt the intestinal microbiota and render the host susceptible to enteric infections. A recent report by Ng et al. explores the ability of two intestinal pathogens (Salmonella enterica serovar Typhimurium and Clostridium difficile) to use this disruption to their advantage and consume host carbohydrates that would otherwise be unavailable in the presence of a normal gut microbiota.

Ecomorphology and disease: cryptic effects of parasitism on host habitat use, thermoregulation, and predator avoidance.

PubMed

Goodman, Brett A; Johnson, Pieter T J

2011-03-01

Parasites can cause dramatic changes in the phenotypes of their hosts, sometimes leading to a higher probability of predation and parasite transmission. Because an organism's morphology directly affects its locomotion, even subtle changes in key morphological traits may affect survival and behavior. However, despite the ubiquity of parasites in natural communities, few studies have incorporated parasites into ecomorphological research. Here, we evaluated the effects of parasite-induced changes in host phenotype on the habitat use, thermal biology, and simulated predator-escape ability of Pacific chorus frogs (Pseudacris regilla) in natural environments. Frogs with parasite-induced limb malformations were more likely to use ground microhabitats relative to vertical refugia and selected less-angled perches closer to the ground in comparison with normal frogs. Although both groups had similar levels of infection, malformed frogs used warmer microhabitats, which resulted in higher body temperatures. Likely as a result of their morphological abnormalities, malformed frogs allowed a simulated predator to approach closer before escaping and escaped shorter distances relative to normal frogs. These data indicate that parasite-induced morphological changes can significantly alter host behavior and habitat use, highlighting the importance of incorporating the ubiquitous, albeit cryptic, role of parasites into ecomorphological research.

ON THE HOST GALAXY OF GRB 150101B AND THE ASSOCIATED ACTIVE GALACTIC NUCLEUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Chen; Fang, Taotao; Wang, Junfeng

We present a multi-wavelength analysis of the host galaxy of short-duration gamma-ray burst (GRB) 150101B. Follow-up optical and X-ray observations suggested that the host galaxy, 2MASX J12320498-1056010, likely harbors low-luminosity active galactic nuclei (AGNs). Our modeling of the spectral energy distribution has confirmed the nature of the AGN, making it the first reported GRB host that contains an AGN. We have also found the host galaxy is a massive elliptical galaxy with stellar population of ∼5.7 Gyr, one of the oldest among the short-duration GRB hosts. Our analysis suggests that the host galaxy can be classified as an X-ray bright,more » optically normal galaxy, and the central AGN is likely dominated by a radiatively inefficient accretion flow. Our work explores an interesting connection that may exist between GRB and AGN activities of the host galaxy, which can help in understanding the host environment of the GRB events and the roles of AGN feedback.« less

Evasion and Immuno-Endocrine Regulation in Parasite Infection: Two Sides of the Same Coin in Chagas Disease?

PubMed Central

Morrot, Alexandre; Villar, Silvina R.; González, Florencia B.; Pérez, Ana R.

2016-01-01

Chagas disease is a serious illness caused by the protozoan parasite Trypanosoma cruzi. Nearly 30% of chronically infected people develop cardiac, digestive, or mixed alterations, suggesting a broad range of host-parasite interactions that finally impact upon chronic disease outcome. The ability of T. cruzi to persist and cause pathology seems to depend on diverse factors like T. cruzi strains, the infective load and the route of infection, presence of virulence factors, the parasite capacity to avoid protective immune response, the strength and type of host defense mechanisms and the genetic background of the host. The host-parasite interaction is subject to a constant neuro-endocrine regulation that is thought to influence the adaptive immune system, and as the infection proceeds it can lead to a broad range of outcomes, ranging from pathogen elimination to its continued persistence in the host. In this context, T. cruzi evasion strategies and host defense mechanisms can be envisioned as two sides of the same coin, influencing parasite persistence and different outcomes observed in Chagas disease. Understanding how T. cruzi evade host's innate and adaptive immune response will provide important clues to better dissect mechanisms underlying the pathophysiology of Chagas disease. PMID:27242726

Ecology of coliphages in southern California coastal waters.

PubMed

Reyes, V C; Jiang, S C

2010-08-01

This study aims to investigate the ecology of coliphages, an important microbial pollution indicator. Specifically, our experiments address (i) the ability of environmental Escherichia coli (E. coli) to serve as hosts for coliphage replication, and (ii) the temporal and spatial distribution of coliphages in coastal waters. Water samples from three locations in California's Newport Bay watershed were tested for the presence of coliphages every 2 weeks for an entire year. A total of nine E. coli strains isolated from various sources served as hosts for coliphage detection. Coliphage occurrence was significantly different between freshwater, estuarine and coastal locations and correlated with water temperature, salinity and rainfall in the watershed. The coliphages isolated on the environmental hosts had a broad host-range relative to the coliphages isolated on an E. coli strain from sewage and a US EPA recommended strain for coliphage detection. Coliphage occurrence was related to the temperature, rainfall and salinity within the bay. The adaptation to a broad host-range may enable the proliferation of coliphages in the aquatic environment. Understanding the seasonal variation of phages is useful for establishing a background level of coliphage presence in coastal waters. The broad host-range of coliphages isolated on the environmental E. coli host calls for investigation of coliphage replication in the aquatic environment.

Gut microbiota: puppeteer of the host juvenile growth.

PubMed

Schwarzer, Martin

2018-05-01

This review focuses on the recent discoveries about the impact of intestinal microbiota on mammalian host juvenile growth. Intestinal microbiota is a powerful modulator of many facets of multicellular host's physiology. Recent results from human field studies and animal research have clearly shown that not only the nutrition, but also the intestinal microbiota impacts host postnatal growth kinetics. Absence of microbiome leads to stunted growth in mammalian gnotobiotic models and changes in the composition of the intestinal microbiota can impact the postnatal growth kinetics both positively and negatively under normal nutritional conditions as well as in undernutrition. Strikingly, specific bacterial strains are able to interact with GH/IGF-1 somatotropic axis activity, thus directly impacting host juvenile development. Intestinal microbiota dictates the pace of host postnatal growth. This newly described role envisages that therapy with specific bacterial strains, together with re-nutritional strategies, might successfully alleviate the long-term sequelae of undernutrition during childhood in humans.

Cellular Signaling Pathways and Posttranslational Modifications Mediated by Nematode Effector Proteins.

PubMed

Hewezi, Tarek

2015-10-01

Plant-parasitic cyst and root-knot nematodes synthesize and secrete a suite of effector proteins into infected host cells and tissues. These effectors are the major virulence determinants mediating the transformation of normal root cells into specialized feeding structures. Compelling evidence indicates that these effectors directly hijack or manipulate refined host physiological processes to promote the successful parasitism of host plants. Here, we provide an update on recent progress in elucidating the molecular functions of nematode effectors. In particular, we emphasize how nematode effectors modify plant cell wall structure, mimic the activity of host proteins, alter auxin signaling, and subvert defense signaling and immune responses. In addition, we discuss the emerging evidence suggesting that nematode effectors target and recruit various components of host posttranslational machinery in order to perturb the host signaling networks required for immunity and to regulate their own activity and subcellular localization. © 2015 American Society of Plant Biologists. All Rights Reserved.

Evolution in action: climate change, biodiversity dynamics and emerging infectious disease.

PubMed

Hoberg, Eric P; Brooks, Daniel R

2015-04-05

Climatological variation and ecological perturbation have been pervasive drivers of faunal assembly, structure and diversification for parasites and pathogens through recurrent events of geographical and host colonization at varying spatial and temporal scales of Earth history. Episodic shifts in climate and environmental settings, in conjunction with ecological mechanisms and host switching, are often critical determinants of parasite diversification, a view counter to more than a century of coevolutionary thinking about the nature of complex host-parasite assemblages. Parasites are resource specialists with restricted host ranges, yet shifts onto relatively unrelated hosts are common during phylogenetic diversification of parasite lineages and directly observable in real time. The emerging Stockholm Paradigm resolves this paradox: Ecological Fitting (EF)--phenotypic flexibility and phylogenetic conservatism in traits related to resource use, most notably host preference--provides many opportunities for rapid host switching in changing environments, without the evolution of novel host-utilization capabilities. Host shifts via EF fuel the expansion phase of the Oscillation Hypothesis of host range and speciation and, more generally, the generation of novel combinations of interacting species within the Geographic Mosaic Theory of Coevolution. In synergy, an environmental dynamic of Taxon Pulses establishes an episodic context for host and geographical colonization. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Determinants of host species range in plant viruses.

PubMed

Moury, Benoît; Fabre, Frédéric; Hébrard, Eugénie; Froissart, Rémy

2017-04-01

Prediction of pathogen emergence is an important field of research, both in human health and in agronomy. Most studies of pathogen emergence have focused on the ecological or anthropic factors involved rather than on the role of intrinsic pathogen properties. The capacity of pathogens to infect a large set of host species, i.e. to possess a large host range breadth (HRB), is tightly linked to their emergence propensity. Using an extensive plant virus database, we found that four traits related to virus genome or transmission properties were strongly and robustly linked to virus HRB. Broader host ranges were observed for viruses with single-stranded genomes, those with three genome segments and nematode-transmitted viruses. Also, two contrasted groups of seed-transmitted viruses were evidenced. Those with a single-stranded genome had larger HRB than non-seed-transmitted viruses, whereas those with a double-stranded genome (almost exclusively RNA) had an extremely small HRB. From the plant side, the family taxonomic rank appeared as a critical threshold for virus host range, with a highly significant increase in barriers to infection between plant families. Accordingly, the plant-virus infectivity matrix shows a dual structure pattern: a modular pattern mainly due to viruses specialized to infect plants of a given family and a nested pattern due to generalist viruses. These results contribute to a better prediction of virus host jumps and emergence risks.

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

PubMed

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 jumps between lagomorphs are observed. The mechanisms responsible for the emergence of pathogenicity and host-species range are unknown. Previous studies showed that RHDV strains attach to glycans expressed in the upper respiratory and digestive tracts of rabbits, the likely doors of virus entry. Here we studied the glycan-binding properties of novel pathogenic and non-pathogenic strains looking for a link between glycan-binding and virulence or between glycan specificity and host range. We found that glycan binding did not correlate with virulence. However, expression of glycan motifs in the upper respiratory and digestive tracts of lagomorphs revealed species-specific patterns associated with the host range of the virus strains, suggesting that glycan diversity contributes to lagoviruses' host range. Copyright © 2017 American Society for Microbiology.

Geochemical and isotopic study of impact melts and spherules from the Lonar impact crater, India, indicate melting of the Precambrian basement beneath the 'target' Deccan basalts

NASA Astrophysics Data System (ADS)

Chakrabarti, R.; Goderis, S.; Banerjee, A.; Gupta, R. D.; Claeys, P.; Vanhaecke, F. F.

2016-12-01

The 1.88 km diameter Lonar impact Crater, with age estimates ranging from 52 -570 ka, is located in the Buldana district of Maharashtra, India. It is an almost circular depression hosted entirely in the 65Ma old basalt flows of the Deccan Traps and is the best-known terrestrial analogue for impact craters in the Inner Solar System. Isotopic studies indicate that the basalts around Lonar correlate with the Poladpur suite, one of the mid-section volcano-stratigraphic units of the Deccan traps. Recently collected samples of the host basalt and impact melts, were analyzed for major and trace element concentrations using ICPMS, as well as for Nd and Sr isotope ratios using TIMS. Relatively more radiogenic Sr and less radiogenic Nd isotopic composition of the melt rocks compared to earlier measurements of similar rocks from Lonar are consistent with melting of the Precambrian basement beneath the Deccan basalt. Spherules ranging in size from 100 mm to 1 mm, were hand-picked under a binocular microscope from unconsolidated soil samples, collected from the south-eastern rim of the crater. Thirty-five spherule samples, screened for surface alteration using SEM were analyzed for major and trace element concentrations including PGEs using LA-ICPMS. The spherules were further classified into two groups using the Chemical Index of Alteration(CIA). Iridium and Cr concentrations of the spherules are consistent with mixing of a chondritic impactor (with 2-8% contribution) with the target rock(s). On a Nb (fluid immobile) -normalized binary plot of Th versus Cr, the composition of the spherules can be explained by mixing between the host basalt and a chondritic impactor with a definite, but minor contribution of the basement beneath Lonar, the composition of which is approximated using the average composition of the upper continental crust (UCC). Variability in the light-REE fractionation of the spherules (La/Sm(N)) can also be explained by a similar three component mixing. Overall, our geochemical data for both the melt rocks and spherules suggest mixing between the chondritic impactor, the Deccan host basalt and the basement rocks at Lonar.

Nematode parasites of waterfowl (Anseriformes) from western United States

USGS Publications Warehouse

McDonald, M.E.

1974-01-01

Thirty-four species of nematodes were found in 415 Anseriformes (Anatidae) of 27 species; 93.7% of birds over 4 weeks old were infected. Data on prevalence, host specificity, age of host, and geographic distribution are given. Infections were more intense in sick birds and birds in poor physical condition. Accidental or abnormal infection was more likely in sick than in normal birds. From 1 to 13 species of nematodes are reported from each host species, including 118 new host records, 3 nematodes new for North America, and 1 new species. Multiple infections were present in 76.5% of birds parasitized; eight species of nematodes were found in one whistling swan (Olor columbianus).

Novel narrow-host-range vectors for direct cloning of foreign DNA in Pseudomonas.

PubMed

Boivin, R; Bellemare, G; Dion, P

1994-01-01

Narrow-host-range vectors, based on an indigenous replicon and containing a multiple cloning site, have been constructed in a Pseudomonas host capable of growth on unusual substrates. The new cloning vectors yield sufficient amounts of DNA for preparative purposes and belong to an incompatibility group different from that of the incP and incQ broad-host-range vectors. One of these vectors, named pDB47F, was used to clone, directly in Pseudomonas, DNA fragments from Agrobacterium, Pseudomonas, and Rhizobium. A clone containing Agrobacterium and KmR gene sequences was transformed with a higher efficiency than an RSF1010-derived vector (by as much as 1250-fold) in four out of five Pseudomonas strains tested. The considerable efficiency obtained with this system makes possible the direct cloning and phenotypic selection of foreign DNA in Pseudomonas.

The role of HBV-induced autophagy in HBV replication and HBV related-HCC.

PubMed

Xie, Mingjie; Yang, Zhenggang; Liu, Yanning; Zheng, Min

2018-04-27

Hepatitis B virus (HBV) is infecting about 364 million people around the world. It can cause various diseases, such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). However, the present anti-viral treatment in clinics is limited; studies for new therapies are highly desired. Autophagy is a crucial and major catabolic process in the maintenance of normal intracellular homeostasis in host cells. Host cells use this unique process to degrade and recycle long-lived proteins, damaged organelles, and various pathogens for keeping the normal physiological functions. Recently, published studies indicated that HBV can induce autophagy in host cells; this autophagic response is involved in viral replication and pathogenesis. Several viral proteins, such as surface and X proteins, are assumed to be responsible for inducing autophagy in HBV infection. This review briefly summarizes some important mechanisms involved in HBV-induced autophagy and provides a novel perspective on therapies of HBV infection and HBV-related HCC. Copyright © 2017. Published by Elsevier Inc.

Regulation of DUOX by the Galphaq-phospholipase Cbeta-Ca2+ pathway in Drosophila gut immunity.

PubMed

Ha, Eun-Mi; Lee, Kyung-Ah; Park, Seon Hwa; Kim, Sung-Hee; Nam, Hyuck-Jin; Lee, Hyo-Young; Kang, Dongmin; Lee, Won-Jae

2009-03-01

All metazoan guts are in constant contact with diverse food-borne microorganisms. The signaling mechanisms by which the host regulates gut-microbe interactions, however, are not yet clear. Here, we show that phospholipase C-beta (PLCbeta) signaling modulates dual oxidase (DUOX) activity to produce microbicidal reactive oxygen species (ROS) essential for normal host survival. Gut-microbe contact rapidly activates PLCbeta through Galphaq, which in turn mobilizes intracellular Ca(2+) through inositol 1,4,5-trisphosphate generation for DUOX-dependent ROS production. PLCbeta mutant flies had a short life span due to the uncontrolled propagation of an essential nutritional microbe, Saccharomyces cerevisiae, in the gut. Gut-specific reintroduction of the PLCbeta restored efficient DUOX-dependent microbe-eliminating capacity and normal host survival. These results demonstrate that the Galphaq-PLCbeta-Ca(2+)-DUOX-ROS signaling pathway acts as a bona fide first line of defense that enables gut epithelia to dynamically control yeast during the Drosophila life cycle.

Odontonema cuspidatum and Psychotria punctata, two new cucumber mosaic virus hosts identified in Florida

USDA-ARS?s Scientific Manuscript database

The wide host range of Cucumber mosaic virus (CMV) has been expanded by the identification of Odontonema cuspidatum (firespike) and Psychotria punctata (dotted wild coffee) as CMV hosts in Florida....

Host specificity and the probability of discovering species of helminth parasites.

PubMed

Poulin, R; Mouillot, D

2005-06-01

Different animal species have different probabilities of being discovered and described by scientists, and these probabilities are determined to a large extent by the biological characteristics of these species. For instance, species with broader geographical ranges are more likely to be encountered by collectors than species with restricted distributions; indeed, the size of the geographical range is often the best predictor of a species' date of description. For parasitic organisms, host specificity may be similarly linked to the probability of a species being found. Here, using data on 170 helminth species parasitic in freshwater fishes, we show that host specificity is associated with the year in which the helminths were described. Helminths that exploit more host species, and to a lesser degree those that exploit a broader taxonomic range of host species, tend to be discovered earlier than the more host-specific helminths. This pattern was observed across all helminth species, as well as within the different helminth taxa (trematodes, cestodes, nematodes and acanthocephalans). Our results demonstrate that the parasite species known at any given point in time are not a random subset of existing species, but rather a biased subset with respect to the parasites' biological properties.

Characterization of Arabidopsis Transcriptional Responses to Different Aphid Species Reveals Genes that Contribute to Host Susceptibility and Non-host Resistance

PubMed Central

Jaouannet, Maëlle; Morris, Jenny A.; Hedley, Peter E.; Bos, Jorunn I. B.

2015-01-01

Aphids are economically important pests that display exceptional variation in host range. The determinants of diverse aphid host ranges are not well understood, but it is likely that molecular interactions are involved. With significant progress being made towards understanding host responses upon aphid attack, the mechanisms underlying non-host resistance remain to be elucidated. Here, we investigated and compared Arabidopsis thaliana host and non-host responses to aphids at the transcriptional level using three different aphid species, Myzus persicae, Myzus cerasi and Rhopalosiphum pisum. Gene expression analyses revealed a high level of overlap in the overall gene expression changes during the host and non-host interactions with regards to the sets of genes differentially expressed and the direction of expression changes. Despite this overlap in transcriptional responses across interactions, there was a stronger repression of genes involved in metabolism and oxidative responses specifically during the host interaction with M. persicae. In addition, we identified a set of genes with opposite gene expression patterns during the host versus non-host interactions. Aphid performance assays on Arabidopsis mutants that were selected based on our transcriptome analyses identified novel genes contributing to host susceptibility, host defences during interactions with M. persicae as well to non-host resistance against R. padi. Understanding how plants respond to aphid species that differ in their ability to infest plant species, and identifying the genes and signaling pathways involved, is essential for the development of novel and durable aphid control in crop plants. PMID:25993686

Impact of simulated microgravity on the normal developmental time line of an animal-bacteria symbiosis

PubMed Central

Foster, Jamie S.; Khodadad, Christina L. M.; Ahrendt, Steven R.; Parrish, Mirina L.

2013-01-01

The microgravity environment during space flight imposes numerous adverse effects on animal and microbial physiology. It is unclear, however, how microgravity impacts those cellular interactions between mutualistic microbes and their hosts. Here, we used the symbiosis between the host squid Euprymna scolopes and its luminescent bacterium Vibrio fischeri as a model system. We examined the impact of simulated microgravity on the timeline of bacteria-induced development in the host light organ, the site of the symbiosis. To simulate the microgravity environment, host squid and symbiosis-competent bacteria were incubated together in high-aspect ratio rotating wall vessel bioreactors and examined throughout the early stages of the bacteria-induced morphogenesis. The host innate immune response was suppressed under simulated microgravity; however, there was an acceleration of bacteria-induced apoptosis and regression in the host tissues. These results suggest that the space flight environment may alter the cellular interactions between animal hosts and their natural healthy microbiome. PMID:23439280

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

PubMed

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.

The Trw Type IV Secretion System of Bartonella Mediates Host-Specific Adhesion to Erythrocytes

PubMed Central

Vayssier-Taussat, Muriel; Le Rhun, Danielle; Deng, Hong Kuan; Biville, Francis; Cescau, Sandra; Danchin, Antoine; Marignac, Geneviève; Lenaour, Evelyne; Boulouis, Henri Jean; Mavris, Maria; Arnaud, Lionel; Yang, Huanming; Wang, Jing; Quebatte, Maxime; Engel, Philipp; Saenz, Henri; Dehio, Christoph

2010-01-01

Bacterial pathogens typically infect only a limited range of hosts; however, the genetic mechanisms governing host-specificity are poorly understood. The α-proteobacterial genus Bartonella comprises 21 species that cause host-specific intraerythrocytic bacteremia as hallmark of infection in their respective mammalian reservoirs, including the human-specific pathogens Bartonella quintana and Bartonella bacilliformis that cause trench fever and Oroya fever, respectively. Here, we have identified bacterial factors that mediate host-specific erythrocyte colonization in the mammalian reservoirs. Using mouse-specific Bartonella birtlesii, human-specific Bartonella quintana, cat-specific Bartonella henselae and rat-specific Bartonella tribocorum, we established in vitro adhesion and invasion assays with isolated erythrocytes that fully reproduce the host-specificity of erythrocyte infection as observed in vivo. By signature-tagged mutagenesis of B. birtlesii and mutant selection in a mouse infection model we identified mutants impaired in establishing intraerythrocytic bacteremia. Among 45 abacteremic mutants, five failed to adhere to and invade mouse erythrocytes in vitro. The corresponding genes encode components of the type IV secretion system (T4SS) Trw, demonstrating that this virulence factor laterally acquired by the Bartonella lineage is directly involved in adherence to erythrocytes. Strikingly, ectopic expression of Trw of rat-specific B. tribocorum in cat-specific B. henselae or human-specific B. quintana expanded their host range for erythrocyte infection to rat, demonstrating that Trw mediates host-specific erythrocyte infection. A molecular evolutionary analysis of the trw locus further indicated that the variable, surface-located TrwL and TrwJ might represent the T4SS components that determine host-specificity of erythrocyte parasitism. In conclusion, we show that the laterally acquired Trw T4SS diversified in the Bartonella lineage to facilitate host-restricted adhesion to erythrocytes in a wide range of mammals. PMID:20548954

Species turnover drives β-diversity patterns across multiple spatial scales of plant-galling interactions in mountaintop grasslands.

PubMed

Coelho, Marcel Serra; Carneiro, Marco Antônio Alves; Branco, Cristina Alves; Borges, Rafael Augusto Xavier; Fernandes, Geraldo Wilson

2018-01-01

This study describes differences in species richness and composition of the assemblages of galling insects and their host plants at different spatial scales. Sampling was conducted along altitudinal gradients composed of campos rupestres and campos de altitude of two mountain complexes in southeastern Brazil: Espinhaço Range and Mantiqueira Range. The following hypotheses were tested: i) local and regional richness of host plants and galling insects are positively correlated; ii) beta diversity is the most important component of regional diversity of host plants and galling insects; and iii) Turnover is the main mechanism driving beta diversity of both host plants and galling insects. Local richness of galling insects and host plants increased with increasing regional richness of species, suggesting a pattern of unsaturated communities. The additive partition of regional richness (γ) into local and beta components shows that local richnesses (α) of species of galling insects and host plants are low relative to regional richness; the beta (β) component incorporates most of the regional richness. The multi-scale analysis of additive partitioning showed similar patterns for galling insects and host plants with the local component (α) incorporated a small part of regional richness. Beta diversity of galling insects and host plants were mainly the result of turnover, with little contribution from nesting. Although the species composition of galling insects and host plant species varied among sample sites, mountains and even mountain ranges, local richness remained relatively low. In this way, the addition of local habitats with different landscapes substantially affects regional richness. Each mountain contributes fundamentally to the composition of regional diversity of galling insects and host plants, and so the design of future conservation strategies should incorporate multiple scales.

Colonization behaviors of mountain pine beetle on novel hosts: Implications for range expansion into northeastern North America

PubMed Central

Venette, Robert C.; Maddox, Mitchell P.; Aukema, Brian H.

2017-01-01

As climates change, thermal limits may no longer constrain some native herbivores within their historical ranges. The mountain pine beetle, Dendroctonus ponderosae Hopkins, is a tree-killing bark beetle native to western North America that is currently expanding its range. Continued eastward expansion through the newly invaded and novel jack pine (Pinus banksiana Lamb.) trees of the Canadian boreal forest could result in exposure of several species of novel potential host pines common in northeastern North America to this oligophagous herbivore. Due to the tightly co-evolved relationship between mountain pine beetle and western pine hosts, in which the insect utilizes the defensive chemistry of the host to stimulate mass attacks, we hypothesized that lack of co-evolutionary association would affect the host attraction and acceptance behaviors of this insect among novel hosts, particularly those with little known historical association with an aggressive stem-infesting insect. We studied how beetle behavior differed among the various stages of colonization on newly cut logs of four novel potential pine host species; jack, red (P. resinosa Ait.), eastern white (P. strobus L.) and Scots (P. sylvestris L.) pines, as well as two historical hosts, ponderosa (P. ponderosa Dougl. ex. Laws. var. scopulorum Engelm.) and lodgepole (P. contorta Dougl. var. latifolia Engelm.) pines. Overall, we found that beetle colonization behaviors at each stage in the colonization process differ between pine hosts, likely due to differing chemical and physical bark traits. Pines without co-evolved constitutive defenses against mountain pine beetle exhibited reduced amounts of defensive monoterpenoid chemicals; however, such patterns also reduced beetle attraction and colonization. Neither chemical nor physical defenses fully defended trees against the various stages of host procurement that can result in tree colonization and death. PMID:28472047

Colonization behaviors of mountain pine beetle on novel hosts: Implications for range expansion into northeastern North America.

PubMed

Rosenberger, Derek W; Venette, Robert C; Maddox, Mitchell P; Aukema, Brian H

2017-01-01

As climates change, thermal limits may no longer constrain some native herbivores within their historical ranges. The mountain pine beetle, Dendroctonus ponderosae Hopkins, is a tree-killing bark beetle native to western North America that is currently expanding its range. Continued eastward expansion through the newly invaded and novel jack pine (Pinus banksiana Lamb.) trees of the Canadian boreal forest could result in exposure of several species of novel potential host pines common in northeastern North America to this oligophagous herbivore. Due to the tightly co-evolved relationship between mountain pine beetle and western pine hosts, in which the insect utilizes the defensive chemistry of the host to stimulate mass attacks, we hypothesized that lack of co-evolutionary association would affect the host attraction and acceptance behaviors of this insect among novel hosts, particularly those with little known historical association with an aggressive stem-infesting insect. We studied how beetle behavior differed among the various stages of colonization on newly cut logs of four novel potential pine host species; jack, red (P. resinosa Ait.), eastern white (P. strobus L.) and Scots (P. sylvestris L.) pines, as well as two historical hosts, ponderosa (P. ponderosa Dougl. ex. Laws. var. scopulorum Engelm.) and lodgepole (P. contorta Dougl. var. latifolia Engelm.) pines. Overall, we found that beetle colonization behaviors at each stage in the colonization process differ between pine hosts, likely due to differing chemical and physical bark traits. Pines without co-evolved constitutive defenses against mountain pine beetle exhibited reduced amounts of defensive monoterpenoid chemicals; however, such patterns also reduced beetle attraction and colonization. Neither chemical nor physical defenses fully defended trees against the various stages of host procurement that can result in tree colonization and death.

LAN attack detection using Discrete Event Systems.

PubMed

Hubballi, Neminath; Biswas, Santosh; Roopa, S; Ratti, Ritesh; Nandi, Sukumar

2011-01-01

Address Resolution Protocol (ARP) is used for determining the link layer or Medium Access Control (MAC) address of a network host, given its Internet Layer (IP) or Network Layer address. ARP is a stateless protocol and any IP-MAC pairing sent by a host is accepted without verification. This weakness in the ARP may be exploited by malicious hosts in a Local Area Network (LAN) by spoofing IP-MAC pairs. Several schemes have been proposed in the literature to circumvent these attacks; however, these techniques either make IP-MAC pairing static, modify the existing ARP, patch operating systems of all the hosts etc. In this paper we propose a Discrete Event System (DES) approach for Intrusion Detection System (IDS) for LAN specific attacks which do not require any extra constraint like static IP-MAC, changing the ARP etc. A DES model is built for the LAN under both a normal and compromised (i.e., spoofed request/response) situation based on the sequences of ARP related packets. Sequences of ARP events in normal and spoofed scenarios are similar thereby rendering the same DES models for both the cases. To create different ARP events under normal and spoofed conditions the proposed technique uses active ARP probing. However, this probing adds extra ARP traffic in the LAN. Following that a DES detector is built to determine from observed ARP related events, whether the LAN is operating under a normal or compromised situation. The scheme also minimizes extra ARP traffic by probing the source IP-MAC pair of only those ARP packets which are yet to be determined as genuine/spoofed by the detector. Also, spoofed IP-MAC pairs determined by the detector are stored in tables to detect other LAN attacks triggered by spoofing namely, man-in-the-middle (MiTM), denial of service etc. The scheme is successfully validated in a test bed. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Morphological Differences Between Seyfert Hosts and Normal Galaxies

NASA Astrophysics Data System (ADS)

Shlosman, Isaac

Using new sub-arcsecond resolution imaging we compare large-scale stellar bar fraction in CfA sample of Seyferts and a closely matched control sample of normal galaxies. We find a difference between the samples on the 2.5σ level. We further compare the axial ratios of bars in all available samples quoted in the literature and find a deficiency of small axial ratio bars in Seyferts compared to normal galaxies.

Expanding the Entamoeba Universe: New Hosts Yield Novel Ribosomal Lineages.

PubMed

Jacob, Alison S; Busby, Eloise J; Levy, Abigail D; Komm, Natasha; Clark, C Graham

2016-01-01

Removing the requirement for cell culture has led to a substantial increase in the number of lineages of Entamoeba recognized as distinct. Surveying the range of potential host species for this parasite genus has barely been started and it is clear that additional sampling of the same host in different locations often identifies additional diversity. In this study, using small subunit ribosomal RNA gene sequencing, we identify four new lineages of Entamoeba, including the first report of Entamoeba from an elephant, and extend the host range of some previously described lineages. In addition, examination of microbiome data from a number of host animals suggests that substantial Entamoeba diversity remains to be uncovered. © 2015 The Author(s) Journal of Eukaryotic Microbiology © 2015 International Society of Protistologists.

The NS2 polypeptide of parvovirus MVM is required for capsid assembly in murine cells.

PubMed

Cotmore, S F; D'Abramo, A M; Carbonell, L F; Bratton, J; Tattersall, P

1997-05-12

Mutants of minute virus of mice (MVM) which express truncated forms of the NS2 polypeptide are known to exhibit a host range defect, replicating productively in transformed human cells but not in cells from their normal murine host. To explore this deficiency we generated viruses with translation termination codons at various positions in the second exon of NS2. In human cells these mutants were viable, but showed a late defect in progeny virion release which put them at a selective disadvantage compared to the wildtype. In murine cells, however, duplex viral DNA amplification was reduced to 5% of wildtype levels and single-strand DNA synthesis was undetectable. These deficiencies could not be attributed to a failure to initiate infection or to a generalized defect in viral gene expression, since the viral replicator protein NS1 was expressed to normal or elevated levels early in infection. In contrast, truncated NS2 gene products failed to accumulate, so that each mutant exhibited a similar NS2-null phenotype. Expression of the capsid polypeptides VP1 and VP2 and their subsequent assembly into intact particles were examined in detail. Synchronized infected cell populations labeled under pulse-chase conditions were analyzed by differential immunoprecipitation of native or denatured extracts using antibodies which discriminated between intact particles and isolated polypeptide chains. These analyses showed that at early times in infection, capsid protein synthesis and stability were normal, but particle assembly was impaired. Unassembled VP proteins were retained in the cell for several hours, but as the unprocessed material accumulated, capsid protein synthesis progressively diminished, so that at later times relatively few VP molecules were synthesized. Thus in NS2-null infections of mouse cells there is a major primary defect in the folding or assembly processes required for effective capsid production.

The influence of normal fault geometry on porous sandstone deformation: Insights from mechanical models into conditions leading to Coulomb failure and shear-enhanced compaction

NASA Astrophysics Data System (ADS)

Allison, K.; Reinen, L. A.

2011-12-01

Slip on non-planar faults produces stress perturbations in the surrounding host rock that can yield secondary faults at a scale too small to be resolved on seismic surveys. Porosity changes during failure may affect the ability of the rock to transmit fluids through dilatant cracking or, in porous rocks, shear-enhanced compaction (i.e., cataclastic flow). Modeling the mechanical behavior of the host rock in response to slip on non-planar faults can yield insights into the role of fault geometry on regions of enhanced or inhibited fluid flow. To evaluate the effect of normal fault geometry on deformation in porous sandstones, we model the system as a linear elastic, homogeneous, whole or half space using the boundary-element modeling program Poly3D. We consider conditions leading to secondary deformation using the maximum Coulomb shear stress (MCSS) as an index of brittle deformation and proximity to an elliptical yield envelope (Y), determined experimentally for porous sandstone (Baud et al., JGR, 2006), for cataclastic flow. We model rectangular faults consisting of two segments: an upper leg with a constant dip of 60° and a lower leg with dips ranging 15-85°. We explore far-field stress models of constant and gradient uniaxial strain. We investigate the potential damage in the host rock in two ways: [1] the size of the damage zone, and [2] regions of enhanced deformation indicated by elevated MCSS or Y. Preliminary results indicate that, along a vertical transect passing through the fault kink, [1] the size of the damage zone increases in the footwall with increasing lower leg dip and remains constant in the hanging wall. [2] In the footwall, the amount of deformation does not change as a function of lower leg dip in constant stress models; in gradient stress models, both MCSS and Y increase with dip. In the hanging wall, Y decreases with increasing lower leg dip for both constant and gradient stress models. In contrast, MCSS increases: as lower leg dip increases for constant stress models, and as the difference between lower leg dip and 60° increases for gradient stress models. These preliminary results indicate that the dip of the lower fault segment significantly affects the amount and style of deformation in the host rock.

Estimating hantavirus risk in southern Argentina: a GIS-based approach combining human cases and host distribution.

PubMed

Andreo, Veronica; Neteler, Markus; Rocchini, Duccio; Provensal, Cecilia; Levis, Silvana; Porcasi, Ximena; Rizzoli, Annapaola; Lanfri, Mario; Scavuzzo, Marcelo; Pini, Noemi; Enria, Delia; Polop, Jaime

2014-01-14

We use a Species Distribution Modeling (SDM) approach along with Geographic Information Systems (GIS) techniques to examine the potential distribution of hantavirus pulmonary syndrome (HPS) caused by Andes virus (ANDV) in southern Argentina and, more precisely, define and estimate the area with the highest infection probability for humans, through the combination with the distribution map for the competent rodent host (Oligoryzomys longicaudatus). Sites with confirmed cases of HPS in the period 1995-2009 were mostly concentrated in a narrow strip (~90 km × 900 km) along the Andes range from northern Neuquén to central Chubut province. This area is characterized by high mean annual precipitation (~1,000 mm on average), but dry summers (less than 100 mm), very low percentages of bare soil (~10% on average) and low temperatures in the coldest month (minimum average temperature -1.5 °C), as compared to the HPS-free areas, features that coincide with sub-Antarctic forests and shrublands (especially those dominated by the invasive plant Rosa rubiginosa), where rodent host abundances and ANDV prevalences are known to be the highest. Through the combination of predictive distribution maps of the reservoir host and disease cases, we found that the area with the highest probability for HPS to occur overlaps only 28% with the most suitable habitat for O. longicaudatus. With this approach, we made a step forward in the understanding of the risk factors that need to be considered in the forecasting and mapping of risk at the regional/national scale. We propose the implementation and use of thematic maps, such as the one built here, as a basic tool allowing public health authorities to focus surveillance efforts and normally scarce resources for prevention and control actions in vast areas like southern Argentina.

Finalizing host range determination of a weed biological control pathogen with BLUPs and damage assessment

USDA-ARS?s Scientific Manuscript database

Colletotrichum gloeosporioides f. sp. salsolae (Penz.) Penz. & Sacc. in Penz. (CGS) is a facultative parasitic fungus being evaluated as a classical biological control agent of Russian thistle or tumbleweed (Salsola tragus L.). In initial host range determination tests, Henderson’s mixed model equat...

Fundamental host range of Leptoypha hospita (Hemiptera: Tingidae), a potential biological control agent of Chinese privet

Treesearch

Yanzhuo Zhang; James L. Hanula; Scott Horn; Cera Jones; S. Kristine Braman; Jianghua Sun

2016-01-01

Chinese privet, Ligustrum sinense Lour., is an invasive shrub within riparian areas of the southeastern United States. Biological control is considered the most suitable management option for Chinese privet. The potential host range of the lace bug, Leptoypha hospita Drake et...

Lack of Host Specialization on Winter Annual Grasses in the Fungal Seed Bank Pathogen Pyrenophora semeniperda

PubMed Central

Beckstead, Julie; Meyer, Susan E.; Ishizuka, Toby S.; McEvoy, Kelsey M.; Coleman, Craig E.

2016-01-01

Generalist plant pathogens may have wide host ranges, but many exhibit varying degrees of host specialization, with multiple pathogen races that have narrower host ranges. These races are often genetically distinct, with each race causing highest disease incidence on its host of origin. We examined host specialization in the seed pathogen Pyrenophora semeniperda by reciprocally inoculating pathogen strains from Bromus tectorum and from four other winter annual grass weeds (Bromus diandrus, Bromus rubens, Bromus arvensis and Taeniatherum caput-medusae) onto dormant seeds of B. tectorum and each alternate host. We found that host species varied in resistance and pathogen strains varied in aggressiveness, but there was no evidence for host specialization. Most variation in aggressiveness was among strains within populations and was expressed similarly on both hosts, resulting in a positive correlation between strain-level disease incidence on B. tectorum and on the alternate host. In spite of this lack of host specialization, we detected weak but significant population genetic structure as a function of host species using two neutral marker systems that yielded similar results. This genetic structure is most likely due to founder effects, as the pathogen is known to be dispersed with host seeds. All host species were highly susceptible to their own pathogen races. Tolerance to infection (i.e., the ability to germinate even when infected and thereby avoid seed mortality) increased as a function of seed germination rate, which in turn increased as dormancy was lost. Pyrenophora semeniperda apparently does not require host specialization to fully exploit these winter annual grass species, which share many life history features that make them ideal hosts for this pathogen. PMID:26950931

Molecular basis of recognition between phytophthora pathogens and their hosts.

PubMed

Tyler, Brett M

2002-01-01

Recognition is the earliest step in any direct plant-microbe interaction. Recognition between Phytophthora pathogens, which are oomycetes, phylogenetically distinct from fungi, has been studied at two levels. Recognition of the host by the pathogen has focused on recognition of chemical, electrical, and physical features of plant roots by zoospores. Both host-specific factors such as isoflavones, and host-nonspecific factors such as amino acids, calcium, and electrical fields, influence zoospore taxis, encystment, cyst germination, and hyphal chemotropism in guiding the pathogen to potential infection sites. Recognition of the pathogen by the host defense machinery has been analyzed using biochemical and genetic approaches. Biochemical approaches have identified chemical elicitors of host defense responses, and in some cases, their cognate receptors from the host. Some elicitors, such as glucans and fatty acids, have broad host ranges, whereas others such as elicitins have narrow host ranges. Most elicitors identified appear to contribute primarily to basic or nonhost resistance. Genetic analysis has identified host resistance (R) genes and pathogen avirulence (Avr) genes that interact in a gene-for-gene manner. One Phytophthora Avr gene, Avr1b from P. sojae, has been cloned and characterized. It encodes a secreted elicitor that triggers a system-wide defense response in soybean plants carrying the cognate R gene, Rps1b.

Quantifying Heterogeneity in Host-Vector Contact: Tsetse (Glossina swynnertoni and G. pallidipes) Host Choice in Serengeti National Park, Tanzania

PubMed Central

Auty, Harriet; Cleaveland, Sarah; Malele, Imna; Masoy, Joseph; Lembo, Tiziana; Bessell, Paul; Torr, Stephen; Picozzi, Kim; Welburn, Susan C.

2016-01-01

Background Identifying hosts of blood-feeding insect vectors is crucial in understanding their role in disease transmission. Rhodesian human African trypanosomiasis (rHAT), also known as acute sleeping sickness is caused by Trypanosoma brucei rhodesiense and transmitted by tsetse flies. The disease is commonly associated with wilderness areas of east and southern Africa. Such areas hold a diverse range of species which form communities of hosts for disease maintenance. The relative importance of different wildlife hosts remains unclear. This study quantified tsetse feeding preferences in a wilderness area of great host species richness, Serengeti National Park, Tanzania, assessing tsetse feeding and host density contemporaneously. Methods Glossina swynnertoni and G. pallidipes were collected from six study sites. Bloodmeal sources were identified through matching Cytochrome B sequences amplified from bloodmeals from recently fed flies to published sequences. Densities of large mammal species in each site were quantified, and feeding indices calculated to assess the relative selection or avoidance of each host species by tsetse. Results The host species most commonly identified in G. swynnertoni bloodmeals, warthog (94/220), buffalo (48/220) and giraffe (46/220), were found at relatively low densities (3-11/km2) and fed on up to 15 times more frequently than expected by their relative density. Wildebeest, zebra, impala and Thomson’s gazelle, found at the highest densities, were never identified in bloodmeals. Commonly identified hosts for G. pallidipes were buffalo (26/46), giraffe (9/46) and elephant (5/46). Conclusions This study is the first to quantify tsetse host range by molecular analysis of tsetse diet with simultaneous assessment of host density in a wilderness area. Although G. swynnertoni and G. pallidipes can feed on a range of species, they are highly selective. Many host species are rarely fed on, despite being present in areas where tsetse are abundant. These feeding patterns, along with the ability of key host species to maintain and transmit T. b. rhodesiense, drive the epidemiology of rHAT in wilderness areas. PMID:27706167

Unravelling the role of host plant expansion in the diversification of a Neotropical butterfly genus.

PubMed

McClure, Melanie; Elias, Marianne

2016-06-16

Understanding the processes underlying diversification is a central question in evolutionary biology. For butterflies, access to new host plants provides opportunities for adaptive speciation. On the one hand, locally abundant host species can generate ecologically significant selection pressure. But a diversity of host plant species within the geographic range of each population and/or species might also eliminate any advantage conferred by specialization. This paper focuses on four Melinaea species, which are oligophagous on the family Solanaceae: M. menophilus, M. satevis, M. marsaeus, and finally, M. mothone. We examined both female preference and larval performance on two host plant species that commonly occur in this butterfly's native range, Juanulloa parasitica and Trianaea speciosa, to determine whether the different Melinaea species show evidence of local adaptation. In choice experiments, M. mothone females used both host plants for oviposition, whereas all other species used J. parasitica almost exclusively. In no choice experiment, M. mothone was the only species that readily accepted T. speciosa as a larval host plant. Larval survival was highest on J. parasitica (82.0 % vs. 60.9 %) and development took longer on T. speciosa (14.12 days vs. 13.35 days), except for M. mothone, which did equally well on both host plants. For all species, average pupal weight was highest on J. parasitica (450.66 mg vs. 420.01 mg), although this difference was least apparent in M. mothone. We did not find that coexisting species of Melinaea partition host plant resources as expected if speciation is primarily driven by host plant divergence. Although M. mothone shows evidence of local adaptation to a novel host plant, T. speciosa, which co-occurs, it does not preferentially lay more eggs on or perform better on this host plant than on host plants used by other Melinaea species and not present in its distributional range. It is likely that diversification in this genus is driven by co-occurring Müllerian mimics and the resulting predation pressure, although this is also likely made possible by greater niche diversity as a consequence of plasticity for potential hosts.

Towards microbial fermentation metabolites as markers for health benefits of prebiotics.

PubMed

Verbeke, Kristin A; Boobis, Alan R; Chiodini, Alessandro; Edwards, Christine A; Franck, Anne; Kleerebezem, Michiel; Nauta, Arjen; Raes, Jeroen; van Tol, Eric A F; Tuohy, Kieran M

2015-06-01

Available evidence on the bioactive, nutritional and putative detrimental properties of gut microbial metabolites has been evaluated to support a more integrated view of how prebiotics might affect host health throughout life. The present literature inventory targeted evidence for the physiological and nutritional effects of metabolites, for example, SCFA, the potential toxicity of other metabolites and attempted to determine normal concentration ranges. Furthermore, the biological relevance of more holistic approaches like faecal water toxicity assays and metabolomics and the limitations of faecal measurements were addressed. Existing literature indicates that protein fermentation metabolites (phenol, p-cresol, indole, ammonia), typically considered as potentially harmful, occur at concentration ranges in the colon such that no toxic effects are expected either locally or following systemic absorption. The endproducts of saccharolytic fermentation, SCFA, may have effects on colonic health, host physiology, immunity, lipid and protein metabolism and appetite control. However, measuring SCFA concentrations in faeces is insufficient to assess the dynamic processes of their nutrikinetics. Existing literature on the usefulness of faecal water toxicity measures as indicators of cancer risk seems limited. In conclusion, at present there is insufficient evidence to use changes in faecal bacterial metabolite concentrations as markers of prebiotic effectiveness. Integration of results from metabolomics and metagenomics holds promise for understanding the health implications of prebiotic microbiome modulation but adequate tools for data integration and interpretation are currently lacking. Similarly, studies measuring metabolite fluxes in different body compartments to provide a more accurate picture of their nutrikinetics are needed.

Influence of leaf color in a dry bean mapping population on Empoasca sp. populations and host plant resistance.

USDA-ARS?s Scientific Manuscript database

Visual cues may be the first line of host plant recognition and an important determining factor when selecting host plants for feeding and oviposition, especially for highly polyphagous insects, such as leafhoppers, which have a broad range of potential host plants. Temperate Empoasca fabae and trop...

Molecular epidemiology and evolution of fish Novirhabdoviruses

USGS Publications Warehouse

Kurath, Gael

2014-01-01

The genus Novirhabdoviridae contains several of the important rhabdoviruses that infect fish hosts. There are four established virus species: Infectious hematopoietic necrosis virus (IHNV), Viral hemorrhagic septicemia virus (VHSV), Hirame rhabdovirus(HIRRV), and Snakehead rhabdovirus (SHRV). Viruses of these species vary in host and geographic range, and they have all been studied at the molecular and genomic level. As globally significant pathogens of cultured fish, IHNV and VHSV have been particularly well studied in terms of molecular epidemiology and evolution. Phylogenic analyses of hundreds of field isolates have defined five major genogroups of IHNV and four major genotypes of VHSV worldwide. These phylogenies are informed by the known histories of IHNV and VHSV, each involving a series of viral emergence events that are sometimes associated with host switches, most often into cultured rainbow trout. In general, IHNV has relatively low genetic diversity and a narrow host range, and has been spread from its endemic source in North American to Europe and Asia due to aquaculture activities. In contrast, VHSV has broad host range and high genetic diversity, and the source of emergence events is virus in widespread marine fish reservoirs in the northern Atlantic and Pacific Oceans. Common mechanisms of emergence and host switch events include use of raw feed, proximity to wild fish reservoirs of virus, and geographic translocations of virus or naive fish hosts associated with aquaculture.

Aphids (Hemiptera, Aphididae) on ornamental plants in greenhouses in Bulgaria

PubMed Central

Yovkova, Mariya; Petrović-Obradović, Olivera; Tasheva-Terzieva, Elena; Pencheva, Aneliya

2013-01-01

Abstract Investigations on the species composition and host range of aphids on ornamental greenhouse plants in Bulgaria was conducted over a period of five years, from 2008 to 2012. Twenty greenhouses, growing ornamentals for landscaping, plant collections and other purposes were observed. They were located in the regions of Sofia, Plovdiv, Smolyan, Pavlikeni, Varna and Burgas. The total number of collected aphid samples was 279. Their composition included 33 aphid species and one subspecies from 13 genera and 5 subfamilies. Twenty-eight species were found to belong to subfamily Aphidinae. Almost 70 % of all recorded species were polyphagous. The most widespread aphid species was Myzus persicae, detected in 13 greenhouses all year round, followed by Aulacorthum solani (10 greenhouses) and Aphis gossypii (9 greenhouses). The widest host range was shown by Myzus persicae (43 hosts), Aulacorthum solani (32 hosts) and Aulacorthum circumflexum (23 hosts). The list of host plants includes 114 species from 95 genera and 58 families. The greatest variety of aphid species was detected on Hibiscus (9 species). Out of all aphid samples 12.9 % were collected on Hibiscus and 6.8 %, on Dendranthema. The greatest variety of aphid species was detected on Hibiscus (9 species). Periphyllus californiensis and Aphis (Aphis) fabae mordvilkoi are reported for the first time for Bulgaria. Furthermore, Aphis spiraecola has been found in new localities and has widened its host range in this country. PMID:24039530

A review of avian probiotics.

PubMed

Smith, Jeanne Marie

2014-06-01

Probiotics have been used in poultry for decades and have become common in the pet bird industry. Desirable characteristics of probiotic organisms are that they are nonpathogenic, have the ability to adhere to intestinal epithelial cells, have the ability to colonize and reproduce in the host, have the ability to be host-specific, survive transit through the gastrointestinal tract and exposure to stomach acid and bile, produce metabolites that inhibit or kill pathogenic bacteria, modulate gastrointestinal immune responses, and survive processing and storage. Purported benefits in birds are disease prevention and promotion of growth. Recommendations for use in avian species are for periodic use to replenish normal flora, use after antibiotic therapy to reestablish normal flora, and use during periods of stress to counter effects of immunosuppression.

Comparative whole genome analysis of six diagnostic brucellaphages.

PubMed

Farlow, Jason; Filippov, Andrey A; Sergueev, Kirill V; Hang, Jun; Kotorashvili, Adam; Nikolich, Mikeljon P

2014-05-15

Whole genome sequencing of six diagnostic brucellaphages, Tbilisi (Tb), Firenze (Fz), Weybridge (Wb), S708, Berkeley (Bk) and R/C, was followed with genomic comparisons including recently described genomes of the Tb phage from Mexico (TbM) and Pr phage to elucidate genomic diversity and candidate host range determinants. Comparative whole genome analysis revealed high sequence homogeneity among these brucellaphage genomes and resolved three genetic groups consistent with defined host range phenotypes. Group I was composed of Tb and Fz phages that are predominantly lytic for Brucella abortus and Brucella neotomae; Group II included Bk, R/C, and Pr phages that are lytic mainly for B. abortus, Brucella melitensis and Brucella suis; Group III was composed of Wb and S708 phages that are lytic for B. suis, B. abortus and B. neotomae. We found that the putative phage collar protein is a variable locus with features that may be contributing to the host specificities exhibited by different brucellaphage groups. The presence of several candidate host range determinants is illustrated herein for future dissection of the differential host specificity observed among these phages. Published by Elsevier B.V.

Symbiotic conversations are revealed under genetic interrogation

PubMed Central

Ruby, Edward G.

2013-01-01

The recent development and application of molecular genetics to the symbionts of invertebrate animal species have advanced our knowledge of the biochemical communication that occurs between the host and its bacterial symbionts. In particular, the ability to manipulate these associations experimentally by introducing genetic variants of the symbionts into naive hosts has allowed the discovery of novel colonization mechanisms and factors. In addition, the role of the symbionts in inducing normal host development has been revealed, and its molecular basis described. In this Review, I discuss many of these developments, focusing on what has been discovered in five well-understood model systems. PMID:18794913

Are adaptation costs necessary to build up a local adaptation pattern?

PubMed

Magalhães, Sara; Blanchet, Elodie; Egas, Martijn; Olivieri, Isabelle

2009-08-03

Ecological specialization is pervasive in phytophagous arthropods. In such specialization mode, limits to host range are imposed by trade-offs preventing adaptation to several hosts. The occurrence of such trade-offs is inferred by a pattern of local adaptation, i.e., a negative correlation between relative performance on different hosts. To establish a causal link between local adaptation and trade-offs, we performed experimental evolution of spider mites on cucumber, tomato and pepper, starting from a population adapted to cucumber. Spider mites adapted to each novel host within 15 generations and no further evolution was observed at generation 25. A pattern of local adaptation was found, as lines evolving on a novel host performed better on that host than lines evolving on other hosts. However, costs of adaptation were absent. Indeed, lines adapted to tomato had similar or higher performance on pepper than lines evolving on the ancestral host (which represent the initial performance of all lines) and the converse was also true, e.g. negatively correlated responses were not observed on the alternative novel host. Moreover, adapting to novel hosts did not result in decreased performance on the ancestral host. Adaptation did not modify host ranking, as all lines performed best on the ancestral host. Furthermore, mites from all lines preferred the ancestral to novel hosts. Mate choice experiments indicated that crosses between individuals from the same or from a different selection regime were equally likely, hence development of reproductive isolation among lines adapted to different hosts is unlikely. Therefore, performance and preference are not expected to impose limits to host range in our study species. Our results show that the evolution of a local adaptation pattern is not necessarily associated with the evolution of an adaptation cost.

Eight new Arthrinium species from China

PubMed Central

Wang, Mei; Tan, Xiao-Ming; Liu, Fang; Cai, Lei

2018-01-01

Abstract The genus Arthrinium includes important plant pathogens, endophytes and saprobes with a wide host range and geographic distribution. In this paper, 74 Arthrinium strains isolated from various substrates such as bamboo leaves, tea plants, soil and air from karst caves in China were examined using a multi-locus phylogeny based on a combined dataset of ITS rDNA, TEF1 and TUB2, in conjunction with morphological characters, host association and ecological distribution. Eight new species were described based on their distinct phylogenetic relationships and morphological characters. Our results indicated a high species diversity of Arthrinium with wide host ranges, amongst which, Poaceae and Cyperaceae were the major host plant families of Arthrinium species. PMID:29755262

Eight new Arthrinium species from China.

PubMed

Wang, Mei; Tan, Xiao-Ming; Liu, Fang; Cai, Lei

2018-01-01

The genus Arthrinium includes important plant pathogens, endophytes and saprobes with a wide host range and geographic distribution. In this paper, 74 Arthrinium strains isolated from various substrates such as bamboo leaves, tea plants, soil and air from karst caves in China were examined using a multi-locus phylogeny based on a combined dataset of ITS rDNA, TEF1 and TUB2, in conjunction with morphological characters, host association and ecological distribution. Eight new species were described based on their distinct phylogenetic relationships and morphological characters. Our results indicated a high species diversity of Arthrinium with wide host ranges, amongst which, Poaceae and Cyperaceae were the major host plant families of Arthrinium species.

Active Galactic Nucleus Host Galaxy Morphologies in COSMOS

NASA Astrophysics Data System (ADS)

Gabor, J. M.; Impey, C. D.; Jahnke, K.; Simmons, B. D.; Trump, J. R.; Koekemoer, A. M.; Brusa, M.; Cappelluti, N.; Schinnerer, E.; Smolčić, V.; Salvato, M.; Rhodes, J. D.; Mobasher, B.; Capak, P.; Massey, R.; Leauthaud, A.; Scoville, N.

2009-01-01

We use Hubble Space Telescope/Advanced Camera for Surveys images and a photometric catalog of the Cosmic Evolution Survey (COSMOS) field to analyze morphologies of the host galaxies of ~400 active galactic nucleus (AGN) candidates at redshifts 0.3 < z < 1.0. We compare the AGN hosts with a sample of nonactive galaxies drawn from the COSMOS field to match the magnitude and redshift distribution of the AGN hosts. We perform two-dimensional surface brightness modeling with GALFIT to yield host galaxy and nuclear point source magnitudes. X-ray-selected AGN host galaxy morphologies span a substantial range that peaks between those of early-type, bulge-dominated and late-type, disk-dominated systems. We also measure the asymmetry and concentration of the host galaxies. Unaccounted for, the nuclear point source can significantly bias results of these measured structural parameters, so we subtract the best-fit point source component to obtain images of the underlying host galaxies. Our concentration measurements reinforce the findings of our two-dimensional morphology fits, placing X-ray AGN hosts between early- and late-type inactive galaxies. AGN host asymmetry distributions are consistent with those of control galaxies. Combined with a lack of excess companion galaxies around AGN, the asymmetry distributions indicate that strong interactions are no more prevalent among AGN than normal galaxies. In light of recent work, these results suggest that the host galaxies of AGN at these X-ray luminosities may be in a transition from disk-dominated to bulge-dominated, but that this transition is not typically triggered by major mergers. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc, under NASA contract NAS 5-26555; also based on data collected at: the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory under Large Program 175.A-0839, Chile; Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and the National Optical Astronomy Observatory, which are operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation; the National Radio Astronomy Observatory which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc; and the Canada-France-Hawaii Telescope with MegaPrime/MegaCam operated as a joint project by the CFHT Corporation, CEA/DAPNIA, the National Research Council of Canada, the Canadian Astronomy Data Centre, the Centre National de la Recherche Scientifique de France, TERAPIX and the University of Hawaii.

Chronic and persistent viral hemorrhagic septicemia virus infections in Pacific herring

USGS Publications Warehouse

Hershberger, P.K.; Gregg, J.L.; Grady, C.A.; Taylor, L.; Winton, J.R.

2010-01-01

Chronic viral hemorrhagic septicemia virus (VHSV) infections were established in a laboratory stock of Pacific herring Clupea pallasii held in a large-volume tank supplied with pathogenfree seawater at temperatures ranging from 6.8 to 11.6??C. The infections were characterized by viral persistence for extended periods and near-background levels of host mortality. Infectious virus was recovered from mortalities occurring up to 167 d post-exposure and was detected in normal-appearing herring for as long as 224 d following initial challenge. Geometric mean viral titers were generally as high as or higher in brain tissues than in pools of kidney and spleen tissues, with overall prevalence of infection being higher in the brain. Upon re-exposure to VHSV in a standard laboratory challenge, negligible mortality occurred among groups of herring that were either chronically infected or fully recovered, indicating that survival from chronic manifestations conferred protection against future disease. However, some survivors of chronic VHS infections were capable of replicating virus upon re-exposure. Demonstration of a chronic manifestation of VHSV infection among Pacific herring maintained at ambient seawater temperatures provides insights into the mechanisms by which the virus is maintained among populations of endemic hosts. ?? 2010 Inter-Research.

Chronic and persistent viral hemorrhagic septicemia virus infections in Pacific herring

USGS Publications Warehouse

Hershberger, Paul K.; Gregg, Jacob L.; Winton, James R.; Grady, Cortney A.; Taylor, L.

2010-01-01

Chronic viral hemorrhagic septicemia virus (VHSV) infections were established in a laboratory stock of Pacific herring Clupea pallasii held in a large-volume tank supplied with pathogen-free seawater at temperatures ranging from 6.8 to 11.6°C. The infections were characterized by viral persistence for extended periods and near-background levels of host mortality. Infectious virus was recovered from mortalities occurring up to 167 d post-exposure and was detected in normal-appearing herring for as long as 224 d following initial challenge. Geometric mean viral titers were generally as high as or higher in brain tissues than in pools of kidney and spleen tissues, with overall prevalence of infection being higher in the brain. Upon re-exposure to VHSV in a standard laboratory challenge, negligible mortality occurred among groups of herring that were either chronically infected or fully recovered, indicating that survival from chronic manifestations conferred protection against future disease. However, some survivors of chronic VHS infections were capable of replicating virus upon re-exposure. Demonstration of a chronic manifestation of VHSV infection among Pacific herring maintained at ambient seawater temperatures provides insights into the mechanisms by which the virus is maintained among populations of endemic hosts.

Friend or foe? Biological and ecological traits of the European ash dieback pathogen Hymenoscyphus fraxineus in its native environment

NASA Astrophysics Data System (ADS)

Cleary, Michelle; Nguyen, Diem; Marčiulynienė, Diana; Berlin, Anna; Vasaitis, Rimvys; Stenlid, Jan

2016-02-01

Hymenoscyphus fraxineus, an introduced ascomycete fungus and primary causal agent of European ash dieback, was investigated on Fraxinus mandshurica trees in its native range in Primorye region of Far East Russia. This evidence is the first report of H. fraxineus on healthy, asymptomatic F. mandshurica trees. High-throughput sequencing revealed 49 distinct fungal taxa associated with leaves of F. mandshurica, 12 of which were identified to species level. Phyllosphere fungal assemblages were similar among sites despite being largely geographically distant. Many organisms comprising the foliar fungal community on F. mandshurica in Far East Russia have similarity to those reported inhabiting F. excelsior in Europe based on previous studies. However, Mycosphaerella sp., the most dominant species in this study and detected in nearly all samples, was associated only with F. mandshurica. Genetic diversity of H. fraxineus was significantly higher in the Far East Russian population than in Europe. In contrast to its aggressive behaviour on Fraxinus excelsior in Europe, H. fraxineus appears to be a benign associate of indigenous F. mandshurica that initially induces quiescent and asymptomatic infections in healthy trees prior to active host colonization normally associated with modification of host tissue during senescence.

Phylogenetic relationships and host range of Rhizobium spp. that nodulate Phaseolus vulgaris L.

PubMed

Hernandez-Lucas, I; Segovia, L; Martinez-Romero, E; Pueppke, S G

1995-07-01

We determined the nucleotide sequences of 16S rRNA gene segments from five Rhizobium strains that have been isolated from tropical legume species. All share the capacity to nodulate Phaseolus vulgaris L., the common bean. Phylogenetic analysis confirmed that these strains are of two different chromosomal lineages. We defined the host ranges of two strains of Rhizobium etli and three strains of R. tropici, comparing them with those of the two most divergently related new strains. Twenty-two of the 43 tested legume species were nodulated by three or more of these strains. All seven strains have broad host ranges that include woody species such as Albizia lebbeck, Gliricidia maculata, and Leucaena leucocephala.

Myxoma Virus M064 Is a Novel Member of the Poxvirus C7L Superfamily of Host Range Factors That Controls the Kinetics of Myxomatosis in European Rabbits

PubMed Central

Liu, Jia; Wennier, Sonia; Moussatche, Nissin; Reinhard, Mary; Condit, Richard

2012-01-01

The myxoma virus (MYXV) carries three tandem C7L-like host range genes (M062R, M063R, and M064R). However, despite the fact that the sequences of these three genes are similar, they possess very distinctive functions in vivo. The role of M064 in MYXV pathogenesis was investigated and compared to the roles of M062 and M063. We report that M064 is a virulence factor that contributes to MYXV pathogenesis but lacks the host range properties associated with M062 and M063. PMID:22379095

Myxoma virus M064 is a novel member of the poxvirus C7L superfamily of host range factors that controls the kinetics of myxomatosis in European rabbits.

PubMed

Liu, Jia; Wennier, Sonia; Moussatche, Nissin; Reinhard, Mary; Condit, Richard; McFadden, Grant

2012-05-01

The myxoma virus (MYXV) carries three tandem C7L-like host range genes (M062R, M063R, and M064R). However, despite the fact that the sequences of these three genes are similar, they possess very distinctive functions in vivo. The role of M064 in MYXV pathogenesis was investigated and compared to the roles of M062 and M063. We report that M064 is a virulence factor that contributes to MYXV pathogenesis but lacks the host range properties associated with M062 and M063.

An optical imaging study of 0.4 ≤ z ≤ 0.8 quasar host galaxies . II. Analysis and interpretation

NASA Astrophysics Data System (ADS)

Örndahl, E.; Rönnback, J.

2005-11-01

We performed optical imaging of 102 radio-loud and radio-quiet quasars at z=0.4{-}0.8, of which 91 fields were found suitable for host galaxy analysis after the deselection of saturated and otherwise flawed images. The data sets were obtained mainly in the R band, but also in the V and I or Gunn i band, and were presented in Rönnback et al.(1996, MNRAS, 283, 282) and Örndahl et al. (2003, A&A, 404, 883). In this paper we combine the two above-mentioned samples and also separately discuss additional hosts, extracted from data taken by Wold et al. (2000, MNRAS, 316, 267; 2001, MNRAS, 323, 231). The joint sample forms a sizeable fraction of the to-date total number of observed sources at intermediate redshifts and increases the number of resolved radio-quiet hosts at z>0.4 considerably. Equal numbers of radio-loud and radio-quiet objects were observed, resulting in a detection rate of 79% for the radio-loud hosts and 66% for the radio-quiet hosts. Profile fitting could only be carried out for a minority of the sample, but it results in predominantly elliptical morphologies. This is consistent with the mean values of the axial ratios, for which we find b/a⪆0.8 for both radio-quiet and radio-loud hosts, just as in the case of normal elliptical galaxies. The mean absolute magnitudes of the radio-loud and radio-quiet hosts is M_R=-23.5 in both cases. This similarity between the mean magnitudes of the two types of host galaxy is also seen in the other imaged bands. While the radio-loud host absolute R magnitudes are correlated with redshift, only a weak trend of the same sort is seen for the radio-quiet host magnitudes. Note, however, that the sample is not fully resolved and that the detection limit, in combination with the relationship between host and nuclear luminosity, may conspire in creating the illusion of an upturn in magnitude. The average nucleus-to-host galaxy luminosity ratios of the radio-loud and radio-quiet objects do not differ significantly in any band, nor is the difference between the average luminosity ratios of flat spectrum and steep spectrum radio-loud quasars larger than 1.5σ. Thus, no effect of beaming (as expected in the unifying scheme) is seen. The colours of both radio-loud and radio-quiet host galaxies are found to be as blue as present-day late-type spirals and starburst galaxies. These blue colours are most likely due neither to galaxy evolution over the range, which only gives rise to a colour shift of 0.2 mag, nor to scattered nuclear light, since colours determined from annular apertures yield very similar results. Since close companions in projection are not uncommon (and a few sources even exhibit tidal tail-like features and other signs of interaction), ongoing star formation is a reasonable explanation of the blue host colours. As multiple-band imaging primarily was carried out for quasars showing indications of the presence of a host galaxy, the colour analysis results are valid for host galaxies which are large, bright, have low nucleus-to-host luminosity ratios, and/or display large scale disturbances, but cannot however safely be generalised to hold for the quasar host galaxy population at intermediate redshift as a whole.

Contrasting determinants of abundance in ancestral and colonized ranges of an invasive brood parasite

USGS Publications Warehouse

Hahn, D.C.; O'Connor, R.J.; Scott, J. Michael; Heglund, Patricia J.; Morrison, Michael L.; Haufler, Jonathan B.; Wall, William A.

2002-01-01

Avian species distributions are typically regarded as constrained by spatially extensive variables such as climate, habitat, spatial patchiness, and microhabitat attributes. We hypothesized that the distribution of a brood parasite depends as strongly on host distribution patterns as on biophysical factors and examined this hypothesis with respect to the national distribution of the Brown-headed Cowbird (Molothrus ater). We applied a classification and regression (CART) analysis to data from the Breeding Bird Survey (BBS) and the Christmas Bird Count (CBC) and derived hierarchically organized statistical models of the influence of climate and weather, cropping and land use, and host abundance and distribution on the distribution of the Brown-headed Cowbird within the conterminous United States. The model accounted for 47.2% of the variation in cowbird incidence, and host abundance was the top predictor with an R2 of 18.9%. The other predictors identified by the model (crops 15.7%, weather and climate 14.3%, and region 9.6%) fit the ecological profile of this cowbird. We showed that host abundance was independent of these environmental predictors of cowbird distribution. At the regional scale host abundance played a very strong role in determining cowbird abundance in the cowbird?s colonized range east and west of their ancestral range in the Great Plains (26.6%). Crops were not a major predictor for cowbirds in their ancestral range, although they are the most important predictive factor (33%) for the grassland passerines that are the cowbird?s ancestral hosts. Consequently our findings suggest that the distribution of hosts does indeed take precedence over habitat attributes in shaping the cowbird?s distribution at a national scale, within an envelope of constraint set by biophysical factors.

Host-directed combinatorial RNAi improves inhibition of diverse strains of influenza A virus in human respiratory epithelial cells.

PubMed

Estrin, Michael A; Hussein, Islam T M; Puryear, Wendy B; Kuan, Anne C; Artim, Stephen C; Runstadler, Jonathan A

2018-01-01

Influenza A virus infections are important causes of morbidity and mortality worldwide, and currently available prevention and treatment methods are suboptimal. In recent years, genome-wide investigations have revealed numerous host factors that are required for influenza to successfully complete its life cycle. However, only a select, small number of influenza strains were evaluated using this platform, and there was considerable variation in the genes identified across different investigations. In an effort to develop a universally efficacious therapeutic strategy with limited potential for the emergence of resistance, this study was performed to investigate the effect of combinatorial RNA interference (RNAi) on inhibiting the replication of diverse influenza A virus subtypes and strains. Candidate genes were selected for targeting based on the results of multiple previous independent genome-wide studies. The effect of single and combinatorial RNAi on the replication of 12 diverse influenza A viruses, including three strains isolated from birds and one strain isolated from seals, was then evaluated in primary normal human bronchial epithelial cells. After excluding overly toxic siRNA, two siRNA combinations were identified that reduced mean viral replication by greater than 79 percent in all mammalian strains, and greater than 68 percent in all avian strains. Host-directed combinatorial RNAi effectively prevents growth of a broad range of influenza virus strains in vitro, and is a potential therapeutic candidate for further development and future in vivo studies.

Only a Few Fungal Species Dominate Highly Diverse Mycofloras Associated with the Common Reed

PubMed Central

Neubert, Karin; Mendgen, Kurt; Brinkmann, Henner; Wirsel, Stefan G. R.

2006-01-01

Plants are naturally colonized by many fungal species that produce effects ranging from beneficial to pathogenic. However, how many of these fungi are linked with a single host plant has not been determined. Furthermore, the composition of plant-associated fungal communities has not been rigorously determined. We investigated these essential issues by employing the perennial wetland reed Phragmites australis as a model. DNA extracted from roots, rhizomes, stems, and leaves was used for amplification and cloning of internal transcribed spacer rRNA gene fragments originating from reed-associated fungi. A total of 1,991 clones from 15 clone libraries were differentiated by restriction fragment length polymorphism analyses into 345 operational taxonomical units (OTUs). Nonparametric estimators for total richness (Chao1 and ACE) and also a parametric log normal model predicted a total of about 750 OTUs if the libraries were infinite. Sixty-two percent of the OTUs sequenced were novel at a threshold of 3%. Several of these OTUs represented undocumented fungal species, which also included higher taxonomic levels. In spite of the high diversity of the OTUs, the mycofloras of vegetative organs were dominated by just a few typical fungi, which suggested that competition and niche differentiation influence the composition of plant-associated fungal communities. This suggestion was independently supported by the results of nested PCR assays specifically monitoring two OTUs over 3 years, which revealed significant preferences for host habitat and host organ. PMID:16461657

Prevalence and differential host-specificity of two avian blood parasite genera in the Australo-Papuan region

USGS Publications Warehouse

Beadell, J.S.; Gering, E.; Austin, J.; Dumbacher, J.P.; Peirce, M.A.; Pratt, T.K.; Atkinson, C.T.; Fleischer, R.C.

2004-01-01

The degree to which widespread avian blood parasites in the genera Plasmodium and Haemoproteus pose a threat to novel hosts depends in part on the degree to which they are constrained to a particular host or host family. We examined the host distribution and host-specificity of these parasites in birds from two relatively understudied and isolated locations: Australia and Papua New Guinea. Using polymerase chain reaction (PCR), we detected infection in 69 of 105 species, representing 44% of individuals surveyed (n = 428). Across host families, prevalence of Haemoproteus ranged from 13% (Acanthizidae) to 56% (Petroicidae) while prevalence of Plasmodium ranged from 3% (Petroicidae) to 47% (Ptilonorhynchidae). We recovered 78 unique mitochondrial lineages from 155 sequences. Related lineages of Haemoproteus were more likely to derive from the same host family than predicted by chance at shallow (average LogDet genetic distance = 0, n = 12, P = 0.001) and greater depths (average distance = 0.014, n = 11, P < 0.001) within the parasite phylogeny. Within two major Haemoproteus subclades identified in a maximum likelihood phylogeny, host-specificity was evident up to parasite genetic distances of 0.029 and 0.007 based on logistic regression. We found no significant host relationship among lineages of Plasmodium by any method of analysis. These results support previous evidence of strong host-family specificity in Haemoproteus and suggest that lineages of Plasmodium are more likely to form evolutionarily-stable associations with novel hosts.

Titan Cells Confer Protection from Phagocytosis in Cryptococcus neoformans Infections

PubMed Central

Okagaki, Laura H.

2012-01-01

The human fungal pathogen Cryptococcus neoformans produces an enlarged “titan” cell morphology when exposed to the host pulmonary environment. Titan cells exhibit traits that promote survival in the host. Previous studies showed that titan cells are not phagocytosed and that increased titan cell production in the lungs results in reduced phagocytosis of cryptococcal cells by host immune cells. Here, the effect of titan cell production on host-pathogen interactions during early stages of pulmonary cryptococcosis was explored. The relationship between titan cell production and phagocytosis was found to be nonlinear; moderate increases in titan cell production resulted in profound decreases in phagocytosis, with significant differences occurring within the first 24 h of the infection. Not only were titan cells themselves protected from phagocytosis, but titan cell formation also conferred protection from phagocytosis to normal-size cryptococcal cells. Large particles introduced into the lungs were not phagocytosed, suggesting the large size of titan cells protects against phagocytosis. The presence of large particles was unable to protect smaller particles from phagocytosis, revealing that titan cell size alone is not sufficient to provide the observed cross-protection of normal-size cryptococcal cells. These data suggest that titan cells play a critical role in establishment of the pulmonary infection by promoting the survival of the entire population of cryptococcal cells. PMID:22544904

Titan cells confer protection from phagocytosis in Cryptococcus neoformans infections.

PubMed

Okagaki, Laura H; Nielsen, Kirsten

2012-06-01

The human fungal pathogen Cryptococcus neoformans produces an enlarged "titan" cell morphology when exposed to the host pulmonary environment. Titan cells exhibit traits that promote survival in the host. Previous studies showed that titan cells are not phagocytosed and that increased titan cell production in the lungs results in reduced phagocytosis of cryptococcal cells by host immune cells. Here, the effect of titan cell production on host-pathogen interactions during early stages of pulmonary cryptococcosis was explored. The relationship between titan cell production and phagocytosis was found to be nonlinear; moderate increases in titan cell production resulted in profound decreases in phagocytosis, with significant differences occurring within the first 24 h of the infection. Not only were titan cells themselves protected from phagocytosis, but titan cell formation also conferred protection from phagocytosis to normal-size cryptococcal cells. Large particles introduced into the lungs were not phagocytosed, suggesting the large size of titan cells protects against phagocytosis. The presence of large particles was unable to protect smaller particles from phagocytosis, revealing that titan cell size alone is not sufficient to provide the observed cross-protection of normal-size cryptococcal cells. These data suggest that titan cells play a critical role in establishment of the pulmonary infection by promoting the survival of the entire population of cryptococcal cells.

Purification of a chymotrypsin-like enzyme present on adult Schistosoma mansoni worms from infected mice and its characterization as a host carboxylesterase.

PubMed

Igetei, Joseph E; Liddell, Susan; El-Faham, Marwa; Doenhoff, Michael J

2016-04-01

A serine protease-like enzyme found in detergent extracts of Schistosoma mansoni adult worms perfused from infected mice has been purified from mouse blood and further characterized. The enzyme is approximately 85 kDa and hydrolyses N-acetyl-DL-phenylalanine β-naphthyl-ester, a chromogenic substrate for chymotrypsin-like enzymes. The enzyme from S. mansoni worms appears to be antigenically and enzymatically similar to a molecule that is present in normal mouse blood and so is seemingly host-derived. The enzyme was partially purified by depleting normal mouse serum of albumin using sodium chloride and cold ethanol, followed by repeated rounds of purification by one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis. The purified material was subjected to tandem mass spectrometry and its derived peptides found to belong to mouse carboxylesterase 1C. Its ability to hydrolyse α- or β-naphthyl acetates, which are general esterase substrates, has been confirmed. A similar carboxylesterase was purified and characterized from rat blood. Additional evidence to support identification of the enzyme as a carboxylesterase has been provided. Possible roles of the enzyme in the mouse host-parasite relationship could be to ease the passage of worms through the host's blood vessels and/or in immune evasion.

Characterization of two biologically distinct variants of Tomato spotted wilt virus

USDA-ARS?s Scientific Manuscript database

Significant economic losses result on a wide range of crops due to infection with Tomato spotted wilt virus (TSWV). In this study, two TSWV isolates, one from basil and a second from tomato, were established in a common plant host. Viral proteins were monitored over time, plant host ranges were comp...

Biology and host range of Heterapoderopsis bicallosicollis; a potential biological control agent for Chinese tallow Triadica sebifera

USDA-ARS?s Scientific Manuscript database

Chinese tallow, Triadica sebifera, is an invasive weed that infests natural and agricultural areas of the southeastern USA. A candidate for biological control of Chinese tallow has been studied under quarantine conditions. The biology and host range of a primitive leaf feeding beetle, Heterapoderops...

Comparison of transcriptomes between Sclerotinia sclerotiorum and S. trifoliorum using 454 Titanium RNA sequencing

USDA-ARS?s Scientific Manuscript database

Sclerotinia sclerotiorum and S. trifoliorum cause Sclerotinia stem and crown rot of chickpea and white mold on many economically important crops. The host range of S. trifoliorum is mainly on cool season forage and grain legumes of about 40 plant species, whereas the host range of S. sclerotiorum ...

Host range of the European leaf sheath mining midge, Lasioptera donacis Coutin, a biological control of giant reed, Arundo donax

USDA-ARS?s Scientific Manuscript database

The fundamental host range of the arundo leafminer, Lasioptera donacis a candidate agent for the invasive weed, Arundo donax was evaluated. Lasioptera donacis collects and inserts spores of a saprophytic fungus, Arthrinium arundinis, during oviposition. Larvae feed and develop in the decomposing le...

Anthropogenic drivers of gypsy moth spread

Treesearch

Kevin M. Bigsby; Patrick C. Tobin; Erin O. Sills

2011-01-01

The gypsy moth, Lymantria dispar (L.), is a polyphagous defoliator introduced to Medford, Massachusetts in 1869. It has spread to over 860,000 km2 in North America, but this still only represents 1/4 of its susceptible host range in the United States. To delay defoliation in the remaining susceptible host range, the government...

NREL to Host Range of Activities for Energy Awareness Month

Science.gov Websites

Host Range of Activities for Energy Awareness Month Events devoted to energy savings Golden, Colo., Sept. 20, 2000 - Visitors will get an inside look at advanced energy technologies and learn tips for cutting utility bills when the U.S. Department of Energy's National Renewable Energy

Evolution on the move: specialization on widespread resources associated with rapid range expansion in response to climate change.

PubMed

Bridle, Jon R; Buckley, James; Bodsworth, Edward J; Thomas, Chris D

2014-02-07

Generalist species and phenotypes are expected to perform best under rapid environmental change. In contrast to this view that generalists will inherit the Earth, we find that increased use of a single host plant is associated with the recent climate-driven range expansion of the UK brown argus butterfly. Field assays of female host plant preference across the UK reveal a diversity of adaptations to host plants in long-established parts of the range, whereas butterflies in recently colonized areas are more specialized, consistently preferring to lay eggs on one host plant species that is geographically widespread throughout the region of expansion, despite being locally rare. By common-garden rearing of females' offspring, we also show an increase in dispersal propensity associated with the colonization of new sites. Range expansion is therefore associated with an increase in the spatial scale of adaptation as dispersive specialists selectively spread into new regions. Major restructuring of patterns of local adaptation is likely to occur across many taxa with climate change, as lineages suited to regional colonization rather than local success emerge and expand.

Infectious disease agents mediate interaction in food webs and ecosystems

PubMed Central

Selakovic, Sanja; de Ruiter, Peter C.; Heesterbeek, Hans

2014-01-01

Infectious agents are part of food webs and ecosystems via the relationship with their host species that, in turn, interact with both hosts and non-hosts. Through these interactions, infectious agents influence food webs in terms of structure, functioning and stability. The present literature shows a broad range of impacts of infectious agents on food webs, and by cataloguing that range, we worked towards defining the various mechanisms and their specific effects. To explore the impact, a direct approach is to study changes in food-web properties with infectious agents as separate species in the web, acting as additional nodes, with links to their host species. An indirect approach concentrates not on adding new nodes and links, but on the ways that infectious agents affect the existing links across host and non-host nodes, by influencing the ‘quality’ of consumer–resource interaction as it depends on the epidemiological state host involved. Both approaches are natural from an ecological point of view, but the indirect approach may connect more straightforwardly to commonly used tools in infectious disease dynamics. PMID:24403336

Mountain pine beetle host selection between lodgepole and ponderosa pines in the southern Rocky Mountains

Treesearch

Daniel R. West; Jennifer S. Briggs; William R. Jacobi; Jose F. Negron

2016-01-01

Recent evidence of range expansion and host transition by mountain pine beetle (Dendroctonus ponderosae Hopkins; MPB) has suggested that MPB may not primarily breed in their natal host, but will switch hosts to an alternate tree species. As MPB populations expanded in lodgepole pine forests in the southern Rocky Mountains, we investigated the potential for...

Amphibian chytridiomycosis: a review with focus on fungus-host interactions.

PubMed

Van Rooij, Pascale; Martel, An; Haesebrouck, Freddy; Pasmans, Frank

2015-11-25

Amphibian declines and extinctions are emblematic for the current sixth mass extinction event. Infectious drivers of these declines include the recently emerged fungal pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans (Chytridiomycota). The skin disease caused by these fungi is named chytridiomycosis and affects the vital function of amphibian skin. Not all amphibians respond equally to infection and host responses might range from resistant, over tolerant to susceptible. The clinical outcome of infection is highly dependent on the amphibian host, the fungal virulence and environmental determinants. B. dendrobatidis infects the skin of a large range of anurans, urodeles and caecilians, whereas to date the host range of B. salamandrivorans seems limited to urodeles. So far, the epidemic of B. dendrobatidis is mainly limited to Australian, neotropical, South European and West American amphibians, while for B. salamandrivorans it is limited to European salamanders. Other striking differences between both fungi include gross pathology and thermal preferences. With this review we aim to provide the reader with a state-of-the art of host-pathogen interactions for both fungi, in which new data pertaining to the interaction of B. dendrobatidis and B. salamandrivorans with the host's skin are integrated. Furthermore, we pinpoint areas in which more detailed studies are necessary or which have not received the attention they merit.

Gill monogenean communities (Platyhelminthes, Monogenea, Dactylogyridae) of butterflyfishes from tropical Indo-West Pacific Islands.

PubMed

Reverter, Miriam; Cutmore, Scott C; Bray, Rodney; Cribb, Thomas H; Sasal, Pierre

2016-10-01

We studied the monogenean communities of 34 species of butterflyfish from the tropical Indo-West Pacific, identifying 13 dactylogyrid species (including two species that are presently undescribed). Monogenean assemblages differed significantly between host species in terms of taxonomic structure, intensity and prevalence. Parasite richness ranged from 0 (Chaetodon lunulatus) to 11 (C. auriga, C. citrinellus and C. lunula). Host specificity varied between the dactylogyrids species, being found on 2-29 of the 34 chaetodontid species examined. Sympatric butterflyfish species were typically parasitized by different combinations of dactylogyrid species, suggesting the existence of complex host-parasite interactions. We identified six clusters of butterflyfish species based on the similarities of their dactylogyrid communities. Dactylogyrid richness and diversity were not related to host size, diet specialization, depth range or phylogeny of butterflyfish species. However, there was a weak positive correlation between monogenean richness and diversity and host geographical range. Most communities of dactylogyrids were dominated by Haliotrema aurigae and H. angelopterum, indicating the importance of the genus Haliotrema in shaping monogenean communities of butterflyfishes. This study casts light on the structure of the monogenean communities of butterflyfishes, suggesting that the diversity and complexity of community structures arises from a combination of host species-specific parameters.

Transplantation Immunity in the Isologous Mouse Radiation Chimaera

PubMed Central

Bridges, J. B.; Loutit, J. F.; Micklem, H. S.

1960-01-01

The survival of skin homo- and heterografts on isologous CBA mouse chimaeras has been investigated. Homografts usually persist for considerably longer than on normal unirradiated mice. Immunization of the host against the appropriate foreign antigens before irradiation neither reduces nor increases the duration of this persistence. When an irradiated non-immune host is restored with bone marrow from an immunized donor, a measure of immunity is transferred. If adult spleen cells from normal or immunized donors are added to the restorative inoculum, strongly antigenic foreign skins are shed with something like normal rapidity, but weakly antigenic skins may be retained for 100 days or more, and even indefinitely. Heterografts do not enjoy a span of survival comparable with that of homografts. These findings are discussed, and it is concluded that two factors are of importance in the prolongation of graft survival: (1) A weakening of the mechanism by which antigens are recognized as foreign, (2) an overall central depression of the immune response. ImagesPLATE IPLATE IIPLATE III PMID:13804388

Biogeochemistry of Neoproterozoic Snowball Earth and its Aftermath in South China

NASA Astrophysics Data System (ADS)

Li, C.; Love, G.; Sessions, A.; Lyons, T.; Chu, X.; Peng, P.

2007-12-01

Using a combination of lipid biomarkers, inorganic geochemical proxies (Fe speciation and trace element analyses) and stable isotopic abundances (13C, 34S, 98Mo), we are reconstructing ocean chemistry and aquatic microbial community structure around the Neoproterozoic Sturtian and Marinoan glacial events and later into the Ediacaran in South China. We have sampled outcrop sediment extensively at four locations (Yichang, Shimen, Minle and Zhaoxin), obtaining sedimentary facies ranging from shallow shelf to the deep basin. Our stratigraphic coverage spans from unweathered sediments of the pre-Sturtian Gongdong Formation up to the post-Marinoan Doushantuo Formation. This approach allows us to compile, for the first time, a highly detailed, spatial and temporal record of Neoproterozoic marine biogeochemistry in South China. To assess and augment conventional extractable biomarker hydrocarbon data, we are using the technique of catalytic hydropyrolysis (HyPy) on kerogen residues to release well-preserved kerogen-bound biomarkers that are much less susceptible to contamination since they are covalently bound within an immobile solid matrix deposited synchronously with the host sediment. Interglacial Datangpo and Ediacaran Doushantuo formations that sandwich the Marinoan diamictites are most interesting for detailed organic and inorganic examination and comparison in this study due to their distinct stratigraphic context and unique spatial preservation. A diverse range of normal, branched (2-methyl, 3-methyl and mid-chain monomethylalkanes) and polycyclic alkanes (steranes and hopanes) have been successfully isolated from Doushantuo sediments in Shimen, and a distinct correlation between host-rock lithology and molecular and isotopic characteristics of detected alkane biomarkers was observed, suggesting that the hydrocarbon signals are indigenous and syngenetic with the host rocks. Sediments with appreciable inorganic carbonate content appear to hold most promise for preserving the original biomarker content, since the acidic clay content of black shales may promote maturation and aromatization of the indigenous organic matter. Temporal trends in our geochemical and isotopic records will be discussed.

Fire blight: applied genomic insights of the pathogen and host

USDA-ARS?s Scientific Manuscript database

The enterobacterial phytopathogen, Erwinia amylovora, causes fire blight, an invasive disease that threatens a wide range of commercial and ornamental Rosaceae host plants. The response elicited by E. amylovora in its host during disease development is similar to the hypersensitive reaction that ty...

Roles of Long and Short Replication Initiation Proteins in the Fate of IncP-1 Plasmids

PubMed Central

Yano, Hirokazu; Deckert, Gail E.; Rogers, Linda M.

2012-01-01

Broad-host-range IncP-1 plasmids generally encode two replication initiation proteins, TrfA1 and TrfA2. TrfA2 is produced from an internal translational start site within trfA1. While TrfA1 was previously shown to be essential for replication in Pseudomonas aeruginosa, its role in other bacteria within its broad host range has not been established. To address the role of TrfA1 and TrfA2 in other hosts, efficiency of transformation, plasmid copy number (PCN), and plasmid stability were first compared between a mini-IncP-1β plasmid and its trfA1 frameshift variant in four phylogenetically distant hosts: Escherichia coli, Pseudomonas putida, Sphingobium japonicum, and Cupriavidus necator. TrfA2 was sufficient for replication in these hosts, but the presence of TrfA1 enhanced transformation efficiency and PCN. However, TrfA1 did not contribute to, and even negatively affected, long-term plasmid persistence. When trfA genes were cloned under a constitutive promoter in the chromosomes of the four hosts, strains expressing either both TrfA1 and TrfA2 or TrfA1 alone, again, generally elicited a higher PCN of an IncP1-β replicon than strains expressing TrfA2 alone. When a single species of TrfA was produced at different concentrations in E. coli cells, TrfA1 maintained a 3- to 4-fold higher PCN than TrfA2 at the same TrfA concentrations, indicating that replication mediated by TrfA1 is more efficient than that by TrfA2. These results suggest that the broad-host-range properties of IncP-1 plasmids are essentially conferred by TrfA2 and the intact replication origin alone but that TrfA1 is nonetheless important to efficiently establish plasmid replication upon transfer into a broad range of hosts. PMID:22228734

δ18O and δD of lake waters across the Coast Range and Cascades, central Oregon: Modern insights from hydrologically open lakes into the control of landscape on lake water composition in deep time

NASA Astrophysics Data System (ADS)

Finkelstein, D. B.; Curtin, T.

2016-12-01

Reconstructing the stable isotopic composition of paleolake water normally requires an assumption of paleotemperature. However, hydrologically open paleolakes with short water residence times may have recorded paleoprecipitation along topographic gradients that are independent of lake water temperature. To identify the environmental and geographic controls on the isotopic composition of lake water, we sampled 22 natural lakes and reservoirs along a longitudinal and elevation gradient from the Pacific Ocean up and over the Coast and Cascade Ranges of central Oregon to the High Lava Plains in 2013 and 2015. The transect spans lakes of different origins, 6 geomorphic regions and an elevation range of 2-1942 m absl. The Coast Range lakes are sand hosted whereas the remaining are bedrock (volcanic and sedimentary) hosted. The lakes are hydrologically open and dominated by meteoric recharge. The water residence time ranges from months to decades. Samples were analyzed for temperature, pH, and total dissolved solids (TDS) in the field, and alkalinity and major cations and anions and stable isotopes of D and O in the lab. The pH ranges from 7 to 9.8 and shows no systematic variation based on substrate type or elevation. The lakes are dilute (avg. TDS = 35.8 ppm) and have low alkalinties (18.9 mg/L CaCO3) except for those in the High Lava Plains (avg. TDS = 337 ppm, alk: 291.2 mg/L CaCO3). In the Coast Range, Na is the major cation on an equivalent basis, reflecting proximity to the ocean. The easternmost lakes within the Coast Range are dominated by Ca, reflecting different drainage basins and substrate type. Lakes in the Western and High Cascades are dominated by Ca. The dominant cation and stable isotopic analyses clearly differentiate waters from different geomorphic regions. The δ18O ranges from -5.7 to -9.3 ‰ (VSMOW), and δD ranges from -37.8 to -63.6 ‰ (VSMOW) in the Coast Range whereas the δ18O ranges from -9.7 to -12.1 ‰ (VSMOW) and δD ranges from -71.5 to -86.5‰ (VSMOW) in the Cascades. Stable isotopic differences between mountain ranges reflect distance from the ocean and increasing elevation. Stable isotopes of water show no correlation with air or lake water temperatures. Average annual precipitation and bedrock across this topographic gradient controls the major ions and stable isotopic composition of these lakes.

The role of fungi in diseases of the nose and sinuses

PubMed Central

Schlosser, Rodney J.

2012-01-01

Background: Human exposure to fungal elements is inevitable, with normal respiration routinely depositing fungal hyphae within the nose and paranasal sinuses. Fungal species can cause sinonasal disease, with clinical outcomes ranging from mild symptoms to intracranial invasion and death. There has been much debate regarding the precise role fungal species play in sinonasal disease and optimal treatment strategies. Methods: A literature review of fungal diseases of the nose and sinuses was conducted. Results: Presentation, diagnosis, and current management strategies of each recognized form of fungal rhinosinusitis was reviewed. Conclusion: Each form of fungal rhinosinusitis has a characteristic presentation and clinical course, with the immune status of the host playing a critical pathophysiological role. Accurate diagnosis and targeted treatment strategies are necessary to achieve optimal outcomes. PMID:23168148

Vision-mediated exploitation of a novel host plant by a tephritid fruit fly.

PubMed

Piñero, Jaime C; Souder, Steven K; Vargas, Roger I

2017-01-01

Shortly after its introduction into the Hawaiian Islands around 1895, the polyphagous, invasive fruit fly Bactrocera (Zeugodacus) cucurbitae (Coquillett) (Diptera: Tephritidae) was provided the opportunity to expand its host range to include a novel host, papaya (Carica papaya). It has been documented that female B. cucurbitae rely strongly on vision to locate host fruit. Given that the papaya fruit is visually conspicuous in the papaya agro-ecosystem, we hypothesized that female B. cucurbitae used vision as the main sensory modality to find and exploit the novel host fruit. Using a comparative approach that involved a series of studies under natural and semi-natural conditions in Hawaii, we assessed the ability of female B. cucurbitae to locate and oviposit in papaya fruit using the sensory modalities of olfaction and vision alone and also in combination. The results of these studies demonstrate that, under a variety of conditions, volatiles emitted by the novel host do not positively stimulate the behavior of the herbivore. Rather, vision seems to be the main mechanism driving the exploitation of the novel host. Volatiles emitted by the novel host papaya fruit did not contribute in any way to the visual response of females. Our findings highlight the remarkable role of vision in the host-location process of B. cucurbitae and provide empirical evidence for this sensory modality as a potential mechanism involved in host range expansion.

Vision-mediated exploitation of a novel host plant by a tephritid fruit fly

PubMed Central

2017-01-01

Shortly after its introduction into the Hawaiian Islands around 1895, the polyphagous, invasive fruit fly Bactrocera (Zeugodacus) cucurbitae (Coquillett) (Diptera: Tephritidae) was provided the opportunity to expand its host range to include a novel host, papaya (Carica papaya). It has been documented that female B. cucurbitae rely strongly on vision to locate host fruit. Given that the papaya fruit is visually conspicuous in the papaya agro-ecosystem, we hypothesized that female B. cucurbitae used vision as the main sensory modality to find and exploit the novel host fruit. Using a comparative approach that involved a series of studies under natural and semi-natural conditions in Hawaii, we assessed the ability of female B. cucurbitae to locate and oviposit in papaya fruit using the sensory modalities of olfaction and vision alone and also in combination. The results of these studies demonstrate that, under a variety of conditions, volatiles emitted by the novel host do not positively stimulate the behavior of the herbivore. Rather, vision seems to be the main mechanism driving the exploitation of the novel host. Volatiles emitted by the novel host papaya fruit did not contribute in any way to the visual response of females. Our findings highlight the remarkable role of vision in the host-location process of B. cucurbitae and provide empirical evidence for this sensory modality as a potential mechanism involved in host range expansion. PMID:28380069

Seasonal parasitism and host specificity of Trissolcus japonicus in northern China

USDA-ARS?s Scientific Manuscript database

The Asian egg parasitoid Trissolcus japonicus is considered the most promising species for classical biological control of Halyomorpha halys. We investigated the fundamental and ecological host range of T. japonicus in northern China to define its host specificity, and we determined that T. japonicu...

lpxC and yafS are the most suitable internal controls to normalize real time RT-qPCR expression in the phytopathogenic bacteria Dickeya dadantii.

PubMed

Hommais, Florence; Zghidi-Abouzid, Ouafa; Oger-Desfeux, Christine; Pineau-Chapelle, Emilie; Van Gijsegem, Frederique; Nasser, William; Reverchon, Sylvie

2011-01-01

Quantitative RT-PCR is the method of choice for studying, with both sensitivity and accuracy, the expression of genes. A reliable normalization of the data, using several reference genes, is critical for an accurate quantification of gene expression. Here, we propose a set of reference genes, of the phytopathogenic bacteria Dickeya dadantii and Pectobacterium atrosepticum, which are stable in a wide range of growth conditions. We extracted, from a D. dadantii micro-array transcript profile dataset comprising thirty-two different growth conditions, an initial set of 49 expressed genes with very low variation in gene expression. Out of these, we retained 10 genes representing different functional categories, different levels of expression (low, medium, and high) and with no systematic variation in expression correlating with growth conditions. We measured the expression of these reference gene candidates using quantitative RT-PCR in 50 different experimental conditions, mimicking the environment encountered by the bacteria in their host and directly during the infection process in planta. The two most stable genes (ABF-0017965 (lpxC) and ABF-0020529 (yafS) were successfully used for normalization of RT-qPCR data. Finally, we demonstrated that the ortholog of lpxC and yafS in Pectobacterium atrosepticum also showed stable expression in diverse growth conditions. We have identified at least two genes, lpxC (ABF-0017965) and yafS (ABF-0020509), whose expressions are stable in a wide range of growth conditions and during infection. Thus, these genes are considered suitable for use as reference genes for the normalization of real-time RT-qPCR data of the two main pectinolytic phytopathogenic bacteria D. dadantii and P. atrosepticum and, probably, of other Enterobacteriaceae. Moreover, we defined general criteria to select good reference genes in bacteria.

Associated disease risk from the introduced generalist pathogen Sphaerothecum destruens: management and policy implications.

PubMed

Andreou, Demetra; Gozlan, Rodolphe Elie

2016-08-01

The rosette agent Sphaerothecum destruens is a novel pathogen, which is currently believed to have been introduced into Europe along with the introduction of the invasive fish topmouth gudgeon Pseudorasbora parva (Temminck & Schlegel, 1846). Its close association with P. parva and its wide host species range and associated host mortalities, highlight this parasite as a potential source of disease emergence in European fish species. Here, using a meta-analysis of the reported S. destruens prevalence across all reported susceptible hosts species; we calculated host-specificity providing support that S. destruens is a true generalist. We have applied all the available information on S. destruens and host-range to an established framework for risk-assessing non-native parasites to evaluate the risks posed by S. destruens and discuss the next steps to manage and prevent disease emergence of this generalist parasite.

Cortical Thinning in Network-Associated Regions in Cognitively Normal and Below-Normal Range Schizophrenia

PubMed Central

Pinnock, Farena; Parlar, Melissa; Hawco, Colin; Hanford, Lindsay; Hall, Geoffrey B.

2017-01-01

This study assessed whether cortical thickness across the brain and regionally in terms of the default mode, salience, and central executive networks differentiates schizophrenia patients and healthy controls with normal range or below-normal range cognitive performance. Cognitive normality was defined using the MATRICS Consensus Cognitive Battery (MCCB) composite score (T = 50 ± 10) and structural magnetic resonance imaging was used to generate cortical thickness data. Whole brain analysis revealed that cognitively normal range controls (n = 39) had greater cortical thickness than both cognitively normal (n = 17) and below-normal range (n = 49) patients. Cognitively normal controls also demonstrated greater thickness than patients in regions associated with the default mode and salience, but not central executive networks. No differences on any thickness measure were found between cognitively normal range and below-normal range controls (n = 24) or between cognitively normal and below-normal range patients. In addition, structural covariance between network regions was high and similar across subgroups. Positive and negative symptom severity did not correlate with thickness values. Cortical thinning across the brain and regionally in relation to the default and salience networks may index shared aspects of the psychotic psychopathology that defines schizophrenia with no relation to cognitive impairment. PMID:28348889

Host range determination of Colletotrichum gloeosporioides f. sp. salsolae, a biological control agent of tumbleweed: from BLUPs to biomass loss

USDA-ARS?s Scientific Manuscript database

Host range tests were conducted with Colletotrichum gloeosporioides f. sp. salsolae (CGS) in quarantine to determine whether the fungus is safe to release in N. America for biological control of tumbleweed (Salsola tragus L., Chenopodiaceae). Ninety-two accessions were analyzed from 19 families and...

Life history and host range of the leaf blotcher Eucosmophora schinusivora; a candidate for biological control of Schinus terebinthifolius in the USA

USDA-ARS?s Scientific Manuscript database

The host range of Eucosmophora schinusivora Davis & Wheeler (Lepidoptera: Gracillariidae) was studied to assess its suitability as a biological control agent of Schinus terebinthifolius Raddi (Anacardiaceae), a serious environmental and agricultural weed in the USA and elsewhere in the world. The l...

Investigation of Host Range, Infectivity, and Spread of Turnip Vein Clearing Virus and a Possible Mechanism for Non-Seed Transmission

USDA-ARS?s Scientific Manuscript database

In this study we investigated the host range, transmission and symptom development of TVCV in several species of plants, as a step toward developing management strategy against seed transmissible viruses. While several species of plants failed to show symptoms of TVCV infection, we report that bush ...

A novel bipolar phosphorescent host for highly efficient deep-red OLEDs at a wide luminance range of 1000-10 000 cd m(-2).

PubMed

Feng, Yansong; Li, Ping; Zhuang, Xuming; Ye, Kaiqi; Peng, Tai; Liu, Yu; Wang, Yue

2015-08-14

A novel phosphorescent host FPYPCA possessing the bipolar charge transporting ability realizes the most efficient deep-red PhOLED, which maintains very high-level EQEs of >23% at rather a high and wide luminance range of 1000-10 000 cd m(-2).

Reproductive biology of Apanteles opuntiarum (Hymenoptera: Braconidae), biological control agent of Cactoblastis cactorum (Lepidoptera: Pyralidae) in Mexico and USA

USDA-ARS?s Scientific Manuscript database

Apanteles opuntiarum, a parasitoid of cactus-feeding lepidopteran larvae, was incorrectly identified as A. alexanderi during the last 50 years. The discovery of A. opuntiarum as a new and separate species was followed by studies of its native host range. These studies revealed that the host range o...

Phylogenetic relationships and host range of Rhizobium spp. that nodulate Phaseolus vulgaris L.

PubMed Central

Hernandez-Lucas, I; Segovia, L; Martinez-Romero, E; Pueppke, S G

1995-01-01

We determined the nucleotide sequences of 16S rRNA gene segments from five Rhizobium strains that have been isolated from tropical legume species. All share the capacity to nodulate Phaseolus vulgaris L., the common bean. Phylogenetic analysis confirmed that these strains are of two different chromosomal lineages. We defined the host ranges of two strains of Rhizobium etli and three strains of R. tropici, comparing them with those of the two most divergently related new strains. Twenty-two of the 43 tested legume species were nodulated by three or more of these strains. All seven strains have broad host ranges that include woody species such as Albizia lebbeck, Gliricidia maculata, and Leucaena leucocephala. PMID:7618891

Noble-gas-rich separates from the Allende meteorite

NASA Technical Reports Server (NTRS)

Ott, U.; Mack, R.; Chang, S.

1981-01-01

Predominantly carbonaceous HF/HCl-resistant residues from the Allende meteorite are studied. Samples are characterized by SEM/EDXA, X-ray diffraction, INAA, C, S, H, N, and noble gas analyses. Isotopic data for carbon show variations no greater than 5%, while isotopic data from noble gases confirm previously established systematics. Noble gas abundances correlate with those of C and N, and concomitant partial loss of C and normal trapped gas occur during treatments with oxidizing acids. HF/HCl demineralization of bulk meteorite results in similar fractional losses of C and trapped noble gases, which leads to the conclusion that various macromolecular carbonaceous substances serve as the main host phase for normal trapped noble gases and anomalous gases in acid-resistant residues, and as the carrier of the major part of trapped noble gases lost during HF/HCl demineralization. Limits on the possible abundances of dense mineralic host phases in the residues are obtained, and considerations of the nucleogenetic origin for CCF-XE indicate that carbonaceous host phases and various forms of organic matter in carbonaceous meteorites may have a presolar origin.

Parasite transmission in social interacting hosts: Monogenean epidemics in guppies

USGS Publications Warehouse

Johnson, M.B.; Lafferty, K.D.; van, Oosterhout C.; Cable, J.

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. ?? 2011 Johnson et al.

Parasite transmission in social interacting hosts: Monogenean epidemics in guppies

USGS Publications Warehouse

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.

Host range testing of Tamarixia radiata (Hymenoptera: Eulophidae) sourced from the Punjab of Pakistan for classical biological control of Diaphorina citri (Hemiptera: Liviidae: Euphyllurinae: Diaphorinini) in California.

PubMed

Hoddle, Mark S; Pandey, Raju

2014-02-01

ABSTRACT Tests evaluating the host range of Tamarixia radiata (Waterson) (Hymenoptera: Eulophidae), a parasitoid of the pestiferous Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from the Punjab of Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species (five native and two self-introduced species) representing five families were exposed to T radiata under the following three different exposure scenarios: 1) sequential no-choice tests, 2) static no-choice tests, and 3) choice tests. Nontarget species were selected for testing based on the following criteria: 1) taxonomic relatedness to the target, D. citri; 2) native psyllids inhabiting native host plants related to citrus that could release volatiles attractive to T. radiata; 3) native psyllids with a high probability of occurrence in native vegetation surrounding commercial citrus groves that could be encountered by T. radiata emigrating from D. citri-infested citrus orchards; 4) a common native pest psyllid species; and 5) a beneficial psyllid attacking a noxious weed. The results of host range testing were unambiguous; T radiata exhibited a narrow host range and high host specificity, with just one species of nontarget psyllid, the abundant native pest Bactericera cockerelli Sulc, being parasitized at low levels (< 5%). These results suggest that the likelihood of significant nontarget impacts is low, and the establishment of T. radiata in southern California for the classical biological control of D. citri poses negligible environmental risk.

A Database of Computer Attacks for the Evaluation of Intrusion Detection Systems

DTIC Science & Technology

1999-06-01

administrator whenever a system binary file (such as the ps, login , or ls program) is modified. Normal users have no legitimate reason to alter these files...development of EMERALD [46], which combines statistical anomaly detection from NIDES with signature verification. Specification-based intrusion detection...the creation of a single host that can act as many hosts. Daemons that provide network services—including telnetd, ftpd, and login — display banners

The Impact of Prophage on the Equilibria and Stability of Phage and Host

NASA Astrophysics Data System (ADS)

Yu, Pei; Nadeem, Alina; Wahl, Lindi M.

2017-06-01

In this paper, we present a bacteriophage model that includes prophage, that is, phage genomes that are incorporated into the host cell genome. The general model is described by an 18-dimensional system of ordinary differential equations. This study focuses on asymptotic behaviour of the model, and thus the system is reduced to a simple six-dimensional model, involving uninfected host cells, infected host cells and phage. We use dynamical system theory to explore the dynamic behaviour of the model, studying in particular the impact of prophage on the equilibria and stability of phage and host. We employ bifurcation and stability theory, centre manifold and normal form theory to show that the system has multiple equilibrium solutions which undergo a series of bifurcations, finally leading to oscillating motions. Numerical simulations are presented to illustrate and confirm the analytical predictions. The results of this study indicate that in some parameter regimes, the host cell population may drive the phage to extinction through diversification, that is, if multiple types of host emerge; this prediction holds even if the phage population is likewise diverse. This parameter regime is restricted, however, if infecting phage are able to recombine with prophage sequences in the host cell genome.

Third-stage larvae of the enoplid nematode Dioctophyme renale (Goeze, 1782) in the freshwater turtle Trachemys dorbigni from southern Brazil.

PubMed

Mascarenhas, C S; Müller, G

2015-09-01

The giant kidney worm Dioctophyme renale is normally found in wild carnivores and domestic dogs, with aquatic oligochaetes acting as intermediate hosts. In the present study a prevalence of 50% of third-stage larvae of D. renale was recorded in 60 specimens of the freshwater turtle Trachemys dorbigni from southern Brazil. Larvae were encysted in muscles, the coelomic cavity and mesentery, the serous lining of the stomach and on the surfaces of the lung, heart, liver, pancreas, spleen and intestines. There are no previous records of reptiles being part of the life cycle of D. renale, although fish and amphibians normally act as paratenic hosts. This is the first report of third-stage D. renale larvae in the freshwater turtle, T. dorbigni.

Stress as a Normal Cue in the Symbiotic Environment.

PubMed

Schwartzman, Julia A; Ruby, Edward G

2016-05-01

All multicellular hosts form associations with groups of microorganisms. These microbial communities can be taxonomically diverse and dynamic, and their persistence is due to robust, and sometimes coevolved, host-microbe and microbe-microbe interactions. Chemical and physical sources of stress are prominently situated in this molecular exchange, as cues for cellular responses in symbiotic microbes. Stress in the symbiotic environment may arise from three sources: host tissues, microbe-induced immune responses, or other microbes in the host environment. The responses of microbes to these stresses can be general or highly specialized, and collectively may contribute to the stability of the symbiotic system. In this review, we highlight recent work that emphasizes the role of stress as a cue in the symbiotic environment of plants and animals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Host galaxies of type ia supernovae from the nearby supernova factory

NASA Astrophysics Data System (ADS)

Childress, Michael Joseph

Type Ia Supernovae (SNe Ia) are excellent distance indicators, yet the full details of the underlying physical mechanism giving rise to these dramatic stellar deaths remain unclear. As large samples of cosmological SNe Ia continue to be collected, the scatter in brightnesses of these events is equally affected by systematic errors as statistical. Thus we need to understand the physics of SNe Ia better, and in particular we must know more about the progenitors of these SNe so that we can derive better estimates for their true intrinsic brightnesses. The host galaxies of SNe Ia provide important indirect clues as to the nature of SN Ia progenitors. In this Thesis we utilize the host galaxies of SNe Ia discovered by the Nearby Supernova Factory (SNfactory) to pursue several key investigations into the nature of SN Ia progenitors and their effects on SN Ia brightnesses. We first examine the host galaxy of SN 2007if, an important member of the subclass of SNe Ia whose extreme brightnesses indicate a progenitor that exceeded the canonical Chandrasekhar-mass value presumed for normal SNe Ia, and show that the host galaxy of this SN is composed of very young stars and has extremely low metallicity, providing important constraints on progenitor scenarios for this SN. We then utilize the full sample of SNfactory host galaxy masses (measured from photometry) and metallicities (derived from optical spectroscopy) to examine several global properties of SN Ia progenitors: (i) we show that SN Ia hosts show tight agreement with the normal galaxy mass-metallicity relation; (ii) comparing the observed distribution of SN Ia host galaxy masses to a theoretical model that couples galaxy physics to the SN Ia delay time distribution (DTD), we show the power of the SN Ia host mass distribution in constraining the SN Ia DTD; and (iii) we show that the lack of ultra-low metallicities in the SNfactory SN Ia host sample gives provisional support for the theorized low-metallicity inhibition of SNe Ia. Finally we revisit recent studies which found that the corrected brightnesses of SNe Ia (after application of the standard light curve width and color corrections) correlate with the masses of their host galaxies. We confirm this trend with host mass using SNfactory data, and for the first time confirm that an analogous trend exists with host metallicity. We then apply a spectroscopic standardization technique developed by SNfactory and show that this method significantly reduces the observed bias. In this Thesis we show that SN Ia host galaxies continue to provide key insight into SN Ia progenitors, and also illuminate possible biases in SN Ia brightness standardization techniques.

Host plants of the wheat stem sawfly (Hymenoptera: Cephidae)

USDA-ARS?s Scientific Manuscript database

Wheat stem sawfly (Cephus cinctus Norton) is a pest of economic importance across much of the wheat cultivating areas of the western Great Plains as well as an ecologically important insect due to its wide range of grass hosts. Little research has been published involving the native host preference ...

Identifying Francisella tularensis genes required for growth in host cells

USDA-ARS?s Scientific Manuscript database

Technical Abstract: Francisella tularensis is a highly virulent Gram negative intracellular pathogen capable of infecting a vast diversity of hosts, ranging from amoebae to humans. A hallmark of F. tularensis virulence is its ability to quickly grow to high densities within a diverse set of host cel...

Uromyces ciceris-arietini, the cause of chickpea rust: new hosts in the Trifolieae, Fabaceae

USDA-ARS?s Scientific Manuscript database

Plants of Medicago polymorpha in Riverside and San Diego, California were collected with severe rust caused by Uromyces ciceris-arietini. Reported hosts of U. ciceris-arietini are Cicer arietinum (chickpea) and Medicago polyceratia. To confirm the potential new host range, a monouredinial isolate RM...

Vision-Mediated exploitation of a novel host plant by a tephritid fruit fly

USDA-ARS?s Scientific Manuscript database

Shortly after its introduction into the Hawaiian Islands around 1895, the polyphagous, invasive fruit fly Bactrocera cucurbitae (Coquillett)(Diptera:Tephritidae) was provided the opportunity to expand its host range to include a novel host, papaya (Carica papaya). It has been documented that female ...

How the study of Listeria monocytogenes has led to new concepts in biology.

PubMed

Rolhion, Nathalie; Cossart, Pascale

2017-06-01

The opportunistic intracellular bacterial pathogen Listeria monocytogenes has in 30 years emerged as an exceptional bacterial model system in infection biology. Research on this bacterium has provided considerable insight into how pathogenic bacteria adapt to mammalian hosts, invade eukaryotic cells, move intracellularly, interfere with host cell functions and disseminate within tissues. It also contributed to unveil features of normal host cell pathways and unsuspected functions of previously known cellular proteins. This review provides an updated overview of our knowledge on this pathogen. In many examples, findings on L. monocytogenes provided the basis for new concepts in bacterial regulation, cell biology and infection processes.

Occurrence of Squash yellow mild mottle virus and Pepper golden mosaic virus in Potential New Hosts in Costa Rica

PubMed Central

Castro, Ruth M.; Moreira, Lisela; Rojas, María R.; Gilbertson, Robert L.; Hernández, Eduardo; Mora, Floribeth; Ramírez, Pilar

2013-01-01

Leaf samples of Solanum lycopersicum, Capsicum annuum, Cucurbita moschata, Cucurbita pepo, Sechium edule and Erythrina spp. were collected. All samples were positive for begomoviruses using polymerase chain reaction and degenerate primers. A sequence of ∼1,100 bp was obtained from the genomic component DNA-A of 14 samples. In addition, one sequence of ∼580 bp corresponding to the coat protein (AV1) was obtained from a chayote (S. edule) leaf sample. The presence of Squash yellow mild mottle virus (SYMMoV) and Pepper golden mosaic virus (PepGMV) were confirmed. The host range reported for SYMMoV includes species of the Cucurbitaceae, Caricaceae and Fabaceae families. This report extends the host range of SYMMoV to include the Solanaceae family, and extends the host range of PepGMV to include C. moschata, C. pepo and the Fabaceae Erythrina spp. This is the first report of a begomovirus (PepGMV) infecting chayote in the Western Hemisphere. PMID:25288955

Occurrence of Squash yellow mild mottle virus and Pepper golden mosaic virus in Potential New Hosts in Costa Rica.

PubMed

Castro, Ruth M; Moreira, Lisela; Rojas, María R; Gilbertson, Robert L; Hernández, Eduardo; Mora, Floribeth; Ramírez, Pilar

2013-09-01

Leaf samples of Solanum lycopersicum, Capsicum annuum, Cucurbita moschata, Cucurbita pepo, Sechium edule and Erythrina spp. were collected. All samples were positive for begomoviruses using polymerase chain reaction and degenerate primers. A sequence of ∼1,100 bp was obtained from the genomic component DNA-A of 14 samples. In addition, one sequence of ∼580 bp corresponding to the coat protein (AV1) was obtained from a chayote (S. edule) leaf sample. The presence of Squash yellow mild mottle virus (SYMMoV) and Pepper golden mosaic virus (PepGMV) were confirmed. The host range reported for SYMMoV includes species of the Cucurbitaceae, Caricaceae and Fabaceae families. This report extends the host range of SYMMoV to include the Solanaceae family, and extends the host range of PepGMV to include C. moschata, C. pepo and the Fabaceae Erythrina spp. This is the first report of a begomovirus (PepGMV) infecting chayote in the Western Hemisphere.

Alternative life-history and transmission strategies in a parasite: first come, first served?

PubMed

Poulin, R; Lefebvre, F

2006-01-01

Alternative transmission strategies are common in many parasitic organisms, often representing discrete phenotypes adopted in response to external cues. The facultative truncation of the normal 3-host life-cycle to a 2-host cycle in many trematodes provides an example: some individuals mature precociously, via progenesis, in their intermediate host and produce eggs without the need to reach a definitive host. The factors that determine how many and which individuals adopt the truncated life-cycle within a parasite population remain unknown. We investigated the occurrence of progenesis in the trematode Stegodexamene anguillae within its fish intermediate host. Location within the host was a key determinant of progenesis. Although the size and egg output of progenetic metacercariae encysted in host gonads did not differ from those of the few progenetic metacercariae in other host tissues, the likelihood of metacercariae becoming progenetic was much higher for those in the gonads than those elsewhere in the host. Progenetic parasites can only evacuate their eggs along with host eggs or sperm, providing a link between the parasite's transmission strategy and its location in the host. Host size and sex, and the presence of other parasite species in the host, did not affect the occurrence of progenesis in S. anguillae. However, the proportion of metacercariae in host gonads and the proportion of progenetic metacercariae both decreased with increasing numbers of S. anguillae per host. These results suggest that progenesis is adopted mostly by the parasites that successfully establish in host gonads. These are generally the first to infect a fish; subsequent arrivals settle in other tissues as the gonads quickly become saturated with parasites. In this system, the site of encystment within the fish host both promotes and constrains the adoption of a facultative, truncated life-cycle by the parasite.

Commensal communism and the oral cavity.

PubMed

Henderson, B; Wilson, M

1998-09-01

The world we live in contains unimaginable numbers of bacteria, and these and other single-celled creatures represent the major diversity of life on our planet. During the last decade or so, the complexity and intimacy of the interactions which occur between bacteria and host eukaryotic cells during the process of infection have begun to emerge. The study of such interactions is the subject of the new discipline of cellular microbiology. This intimacy of bacteria/host interactions creates a major paradox. The average human being is 90% bacteria in terms of cell numbers. These bacteria constitute the commensal or normal microflora and populate the mucosal surfaces of the oral cavity, gastrointestinal tract, urogenital tract, and the surface of the skin. In bacterial infections, much of the pathology is due to the release of a range of bacterial components (e.g., modulins such as lipopolysaccharide, peptidoglycan, DNA, molecular chaperones), which induce the synthesis of the local hormone-like molecules known as pro-inflammatory cytokines. However, such components must also be constantly released by the vast numbers of bacteria constituting the normal microflora and, as a consequence, our mucosae should constantly be in a state of inflammation. This is patently not the case, and a hypothesis is forwarded to account for this "commensal paradox", namely, that our commensal bacteria and mucosal surfaces exist in a state of bio-communism, forming a unified "tissue" in which interactions between bacteria and epithelia are finely balanced to ensure bacterial survival and prevent the induction of damaging inflammation. Evidence is emerging that bacteria can produce a variety of proteins which can inhibit the synthesis/release of inflammatory cytokines. The authors predict that such proteins are simply one part of an extensive signaling system which occurs between bacteria and epithelial cells at mucosal surfaces such as those found in the oral cavity.

Inhibitors of Glioma Growth that Reveal the Tumour to the Immune System

PubMed Central

Nieto-Sampedro, Manuel; Valle-Argos, Beatriz; Gómez-Nicola, Diego; Fernández-Mayoralas, Alfonso; Nieto-Díaz, Manuel

2011-01-01

Treated glioblastoma patients survive from 6 to 14 months. In the first part of this review, we describe glioma origins, cancer stem cells and the genomic alterations that generate dysregulated cell division, with enhanced proliferation and diverse response to radiation and chemotherapy. We review the pathways that mediate tumour cell proliferation, neo-angiogenesis, tumor cell invasion, as well as necrotic and apoptotic cell death. Then, we examine the ability of gliomas to evade and suppress the host immune system, exhibited at the levels of antigen recognition and immune activation, limiting the effective signaling between glioma and host immune cells. The second part of the review presents current therapies and their drawbacks. This is followed by a summary of the work of our laboratory during the past 20 years, on oligosaccharide and glycosphingolipid inhibitors of astroblast and astrocytoma division. Neurostatins, the O-acetylated forms of gangliosides GD1b and GT1b naturally present in mammalian brain, are cytostatic for normal astroblasts, but cytotoxic for rat C6 glioma cells and human astrocytoma grades III and IV, with ID50 values ranging from 200 to 450 nM. The inhibitors do not affect neurons or fibroblasts up to concentrations of 4 μM or higher. At least four different neurostatin-activated, cell-mediated antitumoral processes, lead to tumor destruction: (i) inhibition of tumor neovascularization; (ii) activation of microglia; (iii) activation of natural killer (NK) cells; (iv) activation of cytotoxic lymphocytes (CTL). The enhanced antigenicity of neurostatin-treated glioma cells, could be related to their increased expression of connexin 43. Because neurostatins and their analogues show specific activity and no toxicity for normal cells, a clinical trial would be the logical next step. PMID:22084619

Influential Parameters for the Analysis of Intracellular Parasite Metabolomics.

PubMed

Carey, Maureen A; Covelli, Vincent; Brown, Audrey; Medlock, Gregory L; Haaren, Mareike; Cooper, Jessica G; Papin, Jason A; Guler, Jennifer L

2018-04-25

Metabolomics is increasingly popular for the study of pathogens. For the malaria parasite Plasmodium falciparum , both targeted and untargeted metabolomics have improved our understanding of pathogenesis, host-parasite interactions, and antimalarial drug treatment and resistance. However, purification and analysis procedures for performing metabolomics on intracellular pathogens have not been explored. Here, we purified in vitro -grown ring-stage intraerythrocytic P. falciparum parasites for untargeted metabolomics studies; the small size of this developmental stage amplifies the challenges associated with metabolomics studies as the ratio between host and parasite biomass is maximized. Following metabolite identification and data preprocessing, we explored multiple confounding factors that influence data interpretation, including host contamination and normalization approaches (including double-stranded DNA, total protein, and parasite numbers). We conclude that normalization parameters have large effects on differential abundance analysis and recommend the thoughtful selection of these parameters. However, normalization does not remove the contribution from the parasite's extracellular environment (culture media and host erythrocyte). In fact, we found that extraparasite material is as influential on the metabolome as treatment with a potent antimalarial drug with known metabolic effects (artemisinin). Because of this influence, we could not detect significant changes associated with drug treatment. Instead, we identified metabolites predictive of host and medium contamination that could be used to assess sample purification. Our analysis provides the first quantitative exploration of the effects of these factors on metabolomics data analysis; these findings provide a basis for development of improved experimental and analytical methods for future metabolomics studies of intracellular organisms. IMPORTANCE Molecular characterization of pathogens such as the malaria parasite can lead to improved biological understanding and novel treatment strategies. However, the distinctive biology of the Plasmodium parasite, including its repetitive genome and the requirement for growth within a host cell, hinders progress toward these goals. Untargeted metabolomics is a promising approach to learn about pathogen biology. By measuring many small molecules in the parasite at once, we gain a better understanding of important pathways that contribute to the parasite's response to perturbations such as drug treatment. Although increasingly popular, approaches for intracellular parasite metabolomics and subsequent analysis are not well explored. The findings presented in this report emphasize the critical need for improvements in these areas to limit misinterpretation due to host metabolites and to standardize biological interpretation. Such improvements will aid both basic biological investigations and clinical efforts to understand important pathogens. Copyright © 2018 Carey et al.

Diverse Gastropod Hosts of Angiostrongylus cantonensis, the Rat Lungworm, Globally and with a Focus on the Hawaiian Islands

PubMed Central

Kim, Jaynee R.; Hayes, Kenneth A.; Yeung, Norine W.; Cowie, Robert H.

2014-01-01

Eosinophilic meningitis caused by the parasitic nematode Angiostrongylus cantonensis is an emerging infectious disease with recent outbreaks primarily in tropical and subtropical locations around the world, including Hawaii. Humans contract the disease primarily through ingestion of infected gastropods, the intermediate hosts of Angiostrongylus cantonensis. Effective prevention of the disease and control of the spread of the parasite require a thorough understanding of the parasite's hosts, including their distributions, as well as the human and environmental factors that contribute to transmission. The aim of this study was to screen a large cross section of gastropod species throughout the main Hawaiian Islands to determine which act as hosts of Angiostrongylus cantonensis and to assess the parasite loads in these species. Molecular screening of 7 native and 30 non-native gastropod species revealed the presence of the parasite in 16 species (2 native, 14 non-native). Four of the species tested are newly recorded hosts, two species introduced to Hawaii (Oxychilus alliarius, Cyclotropis sp.) and two native species (Philonesia sp., Tornatellides sp.). Those species testing positive were from a wide diversity of heterobranch taxa as well as two distantly related caenogastropod taxa. Review of the global literature showed that many gastropod species from 34 additional families can also act as hosts. There was a wide range of parasite loads among and within species, with an estimated maximum of 2.8 million larvae in one individual of Laevicaulis alte. This knowledge of the intermediate host range of Angiostrongylus cantonensis and the range of parasite loads will permit more focused efforts to detect, monitor and control the most important hosts, thereby improving disease prevention in Hawaii as well as globally. PMID:24788772

Computational Model for Tumor Oxygenation Applied to Clinical Data on Breast Tumor Hemoglobin Concentrations Suggests Vascular Dilatation and Compression.

PubMed

Welter, Michael; Fredrich, Thierry; Rinneberg, Herbert; Rieger, Heiko

2016-01-01

We present a computational model for trans-vascular oxygen transport in synthetic tumor and host tissue blood vessel networks, aiming at qualitatively explaining published data of optical mammography, which were obtained from 87 breast cancer patients. The data generally show average hemoglobin concentration to be higher in tumors versus host tissue whereas average oxy-to total hemoglobin concentration (vascular segment RBC-volume-weighted blood oxygenation) can be above or below normal. Starting from a synthetic arterio-venous initial network the tumor vasculature was generated by processes involving cooption, angiogenesis, and vessel regression. Calculations of spatially resolved blood flow, hematocrit, oxy- and total hemoglobin concentrations, blood and tissue oxygenation were carried out for ninety tumor and associated normal vessel networks starting from various assumed geometries of feeding arteries and draining veins. Spatial heterogeneity in the extra-vascular partial oxygen pressure distribution can be related to various tumor compartments characterized by varying capillary densities and blood flow characteristics. The reported higher average hemoglobin concentration of tumors is explained by growth and dilatation of tumor blood vessels. Even assuming sixfold metabolic rate of oxygen consumption in tumorous versus host tissue, the predicted oxygen hemoglobin concentrations are above normal. Such tumors are likely associated with high tumor blood flow caused by high-caliber blood vessels crossing the tumor volume and hence oxygen supply exceeding oxygen demand. Tumor oxy- to total hemoglobin concentration below normal could only be achieved by reducing tumor vessel radii during growth by a randomly selected factor, simulating compression caused by intra-tumoral solid stress due to proliferation of cells and extracellular matrix. Since compression of blood vessels will impede chemotherapy we conclude that tumors with oxy- to total hemoglobin concentration below normal are less likely to respond to chemotherapy. Such behavior was recently reported for neo-adjuvant chemotherapy of locally advanced breast tumors.

Computational Model for Tumor Oxygenation Applied to Clinical Data on Breast Tumor Hemoglobin Concentrations Suggests Vascular Dilatation and Compression

PubMed Central

Welter, Michael; Fredrich, Thierry; Rinneberg, Herbert; Rieger, Heiko

2016-01-01

We present a computational model for trans-vascular oxygen transport in synthetic tumor and host tissue blood vessel networks, aiming at qualitatively explaining published data of optical mammography, which were obtained from 87 breast cancer patients. The data generally show average hemoglobin concentration to be higher in tumors versus host tissue whereas average oxy-to total hemoglobin concentration (vascular segment RBC-volume-weighted blood oxygenation) can be above or below normal. Starting from a synthetic arterio-venous initial network the tumor vasculature was generated by processes involving cooption, angiogenesis, and vessel regression. Calculations of spatially resolved blood flow, hematocrit, oxy- and total hemoglobin concentrations, blood and tissue oxygenation were carried out for ninety tumor and associated normal vessel networks starting from various assumed geometries of feeding arteries and draining veins. Spatial heterogeneity in the extra-vascular partial oxygen pressure distribution can be related to various tumor compartments characterized by varying capillary densities and blood flow characteristics. The reported higher average hemoglobin concentration of tumors is explained by growth and dilatation of tumor blood vessels. Even assuming sixfold metabolic rate of oxygen consumption in tumorous versus host tissue, the predicted oxygen hemoglobin concentrations are above normal. Such tumors are likely associated with high tumor blood flow caused by high-caliber blood vessels crossing the tumor volume and hence oxygen supply exceeding oxygen demand. Tumor oxy- to total hemoglobin concentration below normal could only be achieved by reducing tumor vessel radii during growth by a randomly selected factor, simulating compression caused by intra-tumoral solid stress due to proliferation of cells and extracellular matrix. Since compression of blood vessels will impede chemotherapy we conclude that tumors with oxy- to total hemoglobin concentration below normal are less likely to respond to chemotherapy. Such behavior was recently reported for neo-adjuvant chemotherapy of locally advanced breast tumors. PMID:27547939

Structural controls of the Tuscarora geothermal field, Elko County, Nevada

NASA Astrophysics Data System (ADS)

Dering, G.; Faulds, J. E.

2012-12-01

Tuscarora is an amagmatic geothermal system located ~90 km northwest of Elko, Nevada, in the northern part of the Basin and Range province ~15 km southeast of the Snake River Plain. Detailed geologic mapping, structural analysis, and well data have been integrated to identify the structural controls of the Tuscarora geothermal system. The structural framework of the geothermal field is defined by NNW- to NNE-striking normal faults that are approximately orthogonal to the present extension direction. Boiling springs, fumaroles, and siliceous sinter emanate from a single NNE-striking, west-dipping normal fault. Normal faults west of these hydrothermal features mostly dip steeply east, whereas normal faults east of the springs primarily dip west. Thus, the springs, fumaroles, and sinter straddle a zone of interaction between fault sets that dip toward each other, classified as a strike-parallel anticlinal accommodation zone. Faults within the geothermal area are mostly discontinuous along strike with offsets of tens to hundreds of meters, whereas the adjacent range-bounding fault systems of the Bull Run and Independence Mountains accommodate several kilometers of displacement. The geothermal field lies within a broad step over between the southward terminating west-dipping Bull Run fault zone and the northward terminating west-dipping Independence Mountains fault zone. Neither of these major fault zones is known to host high temperature geothermal systems. The accommodation zone lies within the broad step over and contains both east-dipping antithetic and west-dipping synthetic faults. Accommodation zones are relatively common structural components of extended terranes that transfer strain between oppositely dipping fault sets via a network of subsidiary normal faults. This study has identified the hinge zone of an anticlinal accommodation zone as the site most conducive to fluid up-flow. The recognition of this specific portion of an accommodation zone as a favorable structural setting for geothermal activity may be a useful exploration tool for development of drilling targets in extensional terranes, as well as for developing geologic models of known geothermal fields. This type of information may ultimately help to reduce the risks of targeting successful geothermal wells in such settings.

Interplay between Candida albicans and the Mammalian Innate Host Defense

PubMed Central

Cheng, Shih-Chin; Joosten, Leo A. B.; Kullberg, Bart-Jan

2012-01-01

Candida albicans is both the most common fungal commensal microorganism in healthy individuals and the major fungal pathogen causing high mortality in at-risk populations, especially immunocompromised patients. In this review, we summarize the interplay between the host innate system and C. albicans, ranging from how the host recognizes, responds, and clears C. albicans infection to how C. albicans evades, dampens, and escapes from host innate immunity. PMID:22252867

Pathogenic and host range determinants of the feline aplastic anemia retrovirus.

PubMed Central

Riedel, N; Hoover, E A; Dornsife, R E; Mullins, J I

1988-01-01

Feline leukemia virus (FeLV) C-Sarma (or FSC) is a prototype of subgroup C FeLVs, which induce fatal aplastic anemia in outbred specific-pathogen-free (SPF) cats. FeLV C isolates also possess an extended host range in vitro, including an ability, unique among FeLVs, to replicate in guinea pig cells. To identify the viral determinants responsible for the pathogenicity and host range of FSC we constructed a series of proviral DNAs by exchanging gene fragments between FSC and FeLV-61E (or F6A), the latter of which is minimally pathogenic and whose host range in vitro is restricted to feline cells. Transfer of an 886-base-pair (bp) fragment of FSC, encompassing the codons for 73 amino acids at the 3' end of pol (the integrase/endonuclease gene) and the codons for 241 amino acids of the N-terminal portion of env [the extracellular glycoprotein (gp70) gene], into the F6A genome was sufficient to confer onto chimeric viruses the ability to induce fatal aplastic anemia in SPF cats. In contrast, no chimera lacking this sequence induced disease. When assayed in vitro, all chimeric viruses containing the 886-bp fragment of FSC acquired the ability to replicate in heterologous cells, including dog and guinea pig cells. Thus, the pathogenic and the host range determinants of the feline aplastic anemia retrovirus colocalize to a 3' pol-5' env region of the FSC genome and likely reside within a region encoding 241 amino acid residues of the N terminus of the extracellular glycoprotein. Images PMID:2833751

Patterns of host-plant choice in bees of the genus Chelostoma: the constraint hypothesis of host-range evolution in bees.

PubMed

Sedivy, Claudio; Praz, Christophe J; Müller, Andreas; Widmer, Alex; Dorn, Silvia

2008-10-01

To trace the evolution of host-plant choice in bees of the genus Chelostoma (Megachilidae), we assessed the host plants of 35 Palearctic, North American and Indomalayan species by microscopically analyzing the pollen loads of 634 females and reconstructed their phylogenetic history based on four genes and a morphological dataset, applying both parsimony and Bayesian methods. All species except two were found to be strict pollen specialists at the level of plant family or genus. These oligolectic species together exploit the flowers of eight different plant orders that are distributed among all major angiosperm lineages. Based on ancestral state reconstruction, we found that oligolecty is the ancestral state in Chelostoma and that the two pollen generalists evolved from oligolectic ancestors. The distinct pattern of host broadening in these two polylectic species, the highly conserved floral specializations within the different clades, the exploitation of unrelated hosts with a striking floral similarity as well as a recent report on larval performance on nonhost pollen in two Chelostoma species clearly suggest that floral host choice is physiologically or neurologically constrained in bees of the genus Chelostoma. Based on this finding, we propose a new hypothesis on the evolution of host range in bees.

Host and parasite thermal ecology jointly determine the effect of climate warming on epidemic dynamics.

PubMed

Gehman, Alyssa-Lois M; Hall, Richard J; Byers, James E

2018-01-23

Host-parasite systems have intricately coupled life cycles, but each interactor can respond differently to changes in environmental variables like temperature. Although vital to predicting how parasitism will respond to climate change, thermal responses of both host and parasite in key traits affecting infection dynamics have rarely been quantified. Through temperature-controlled experiments on an ectothermic host-parasite system, we demonstrate an offset in the thermal optima for survival of infected and uninfected hosts and parasite production. We combine experimentally derived thermal performance curves with field data on seasonal host abundance and parasite prevalence to parameterize an epidemiological model and forecast the dynamical responses to plausible future climate-warming scenarios. In warming scenarios within the coastal southeastern United States, the model predicts sharp declines in parasite prevalence, with local parasite extinction occurring with as little as 2 °C warming. The northern portion of the parasite's current range could experience local increases in transmission, but assuming no thermal adaptation of the parasite, we find no evidence that the parasite will expand its range northward under warming. This work exemplifies that some host populations may experience reduced parasitism in a warming world and highlights the need to measure host and parasite thermal performance to predict infection responses to climate change.

Five challenges in evolution and infectious diseases.

PubMed

Metcalf, C J E; Birger, R B; Funk, S; Kouyos, R D; Lloyd-Smith, J O; Jansen, V A A

2015-03-01

Evolution is a key aspect of the biology of many pathogens, driving processes ranging from immune escape to changes in virulence. Because evolution is inherently subject to feedbacks, and because pathogen evolution plays out at scales ranging from within-host to between-host and beyond, evolutionary questions provide special challenges to the modelling community. In this article, we provide an overview of five challenges in modelling the evolution of pathogens and their hosts, and point to areas for development, focussing in particular on the issue of linking theory and data. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

A novel pathogenic aviadenovirus from red-bellied parrots (Poicephalus rufiventris) unveils deep recombination events among avian host lineages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Shubhagata, E-mail: sdas@csu.edu.au

Competing roles of coevolution, selective pressure and recombination are an emerging interest in virus evolution. We report a novel aviadenovirus from captive red-bellied parrots (Poicephalus rufiventris) that uncovers evidence of deep recombination among aviadenoviruses. The sequence identity of the virus was most closely related to Turkey adenovirus D (42% similarity) and other adenoviruses in chickens, turkeys and pigeons. Sequencing and comparative analysis showed that the genome comprised 40,930 nucleotides containing 42 predicted open reading frames (ORFs) 19 of which had strong similarity with genes from other adenovirus species. The new genome unveiled a lineage that likely participated in deep recombinationmore » events across the genus Aviadenovirus accounting for an ancient evolutionary relationship. We hypothesize frequent host switch events and recombination among adenovirus progenitors in Galloanserae hosts caused the radiation of extant aviadenoviruses and the newly assembled Poicephalus adenovirus genome points to a potentially broader host range of these viruses among birds. - Highlights: •Shows how a single new genome can change overall phylogeny. •Reveals host switch events among adenovirus progenitors in Galloanserae hosts. •Points to a potentially broader host range of adenoviruses among birds and wildlife .« less

Host specificity in biological control: insights from opportunistic pathogens

PubMed Central

Brodeur, Jacques

2012-01-01

Host/prey specificity is a significant concern in biological control. It influences the effectiveness of a natural enemy and the risks it might have on non-target organisms. Furthermore, narrow host specificity can be a limiting factor for the commercialization of natural enemies. Given the great diversity in taxonomy and mode of action of natural enemies, host specificity is a highly variable biological trait. This variability can be illustrated by opportunist fungi from the genus Lecanicillium, which have the capacity to exploit a wide range of hosts – from arthropod pests to fungi causing plant diseases – through different modes of action. Processes determining evolutionary trajectories in host specificity are closely linked to the modes of action of the natural enemy. This hypothesis is supported by advances in fungal genomics concerning the identity of genes and biological traits that are required for the evolution of life history strategies and host range. Despite the significance of specificity, we still need to develop a conceptual framework for better understanding of the relationship between specialization and successful biological control. The emergence of opportunistic pathogens and the development of ‘omic’ technologies offer new opportunities to investigate evolutionary principles and applications of the specificity of biocontrol agents. PMID:22949922

Interaction between Host MicroRNAs and the Gut Microbiota in Colorectal Cancer.

PubMed

Yuan, Ce; Burns, Michael B; Subramanian, Subbaya; Blekhman, Ran

2018-01-01

Although variation in gut microbiome composition has been linked with colorectal cancer (CRC), the factors that mediate the interactions between CRC tumors and the microbiome are poorly understood. MicroRNAs (miRNAs) are known to regulate CRC progression and are associated with patient survival outcomes. In addition, recent studies suggested that host miRNAs can also regulate bacterial growth and influence the composition of the gut microbiome. Here, we investigated the association between miRNA expression and microbiome composition in human CRC tumor and normal tissues. We identified 76 miRNAs as differentially expressed (DE) in tissue from CRC tumors and normal tissue, including the known oncogenic miRNAs miR-182, miR-503, and mir-17~92 cluster. These DE miRNAs were correlated with the relative abundances of several bacterial taxa, including Firmicutes , Bacteroidetes , and Proteobacteria . Bacteria correlated with DE miRNAs were enriched with distinct predicted metabolic categories. Additionally, we found that miRNAs that correlated with CRC-associated bacteria are predicted to regulate targets that are relevant for host-microbiome interactions and highlight a possible role for miRNA-driven glycan production in the recruitment of pathogenic microbial taxa. Our work characterized a global relationship between microbial community composition and miRNA expression in human CRC tissues. IMPORTANCE Recent studies have found an association between colorectal cancer (CRC) and the gut microbiota. One potential mechanism by which the microbiota can influence host physiology is through affecting gene expression in host cells. MicroRNAs (miRNAs) are small noncoding RNA molecules that can regulate gene expression and have important roles in cancer development. Here, we investigated the link between the gut microbiota and the expression of miRNA in CRC. We found that dozens of miRNAs are differentially regulated in CRC tumors and adjacent normal colon and that these miRNAs are correlated with the abundance of microbes in the tumor microenvironment. Moreover, we found that microbes that have been previously associated with CRC are correlated with miRNAs that regulate genes related to interactions with microbes. Notably, these miRNAs likely regulate glycan production, which is important for the recruitment of pathogenic microbial taxa to the tumor. This work provides a first systems-level map of the association between microbes and host miRNAs in the context of CRC and provides targets for further experimental validation and potential interventions.

Biology and host range of Tecmessa elegans (Lepidoptera: Notodontidae), a leaf-feeding moth evaluated as a potential biological control agent for Schinus terebinthifolius (Sapindales: Anacardiaceae) in the United States.

PubMed

Oleiro, Marina; Mc Kay, Fernando; Wheeler, Gregory S

2011-06-01

During surveys for natural enemies that could be used as classical biological control agents of Schinus terebinthifolius Raddi (Brazilian pepper), the caterpillar, Tecmessa elegans Schaus (Lepidoptera: Notodontidae), was recorded feeding on the leaves of the shrub in South America. The biology and larval and adult host range of this species were examined to determine the insect's suitability for biological control of this invasive weed in North America and Hawaii. Biological observations indicate that the larvae have five instars. When disturbed, the late instar larvae emit formic acid from a prothoracic gland that may protect larvae from generalist predators. Larval host range tests conducted both in South and North America indicated that this species feeds and completes development primarily on members of the Anacardiaceae within the tribe Rhoeae. Oviposition tests indicated that when given a choice in large cages the adults will select the target weed over Pistacia spp. However, considering the many valued plant species in its host range, especially several North American natives, this species will not be considered further for biological control of S. terebinthifolius in North America.

Subdiffusive motion of bacteriophage in mucosal surfaces increases the frequency of bacterial encounters.

PubMed

Barr, Jeremy J; Auro, Rita; Sam-Soon, Nicholas; Kassegne, Sam; Peters, Gregory; Bonilla, Natasha; Hatay, Mark; Mourtada, Sarah; Bailey, Barbara; Youle, Merry; Felts, Ben; Baljon, Arlette; Nulton, Jim; Salamon, Peter; Rohwer, Forest

2015-11-03

Bacteriophages (phages) defend mucosal surfaces against bacterial infections. However, their complex interactions with their bacterial hosts and with the mucus-covered epithelium remain mostly unexplored. Our previous work demonstrated that T4 phage with Hoc proteins exposed on their capsid adhered to mucin glycoproteins and protected mucus-producing tissue culture cells in vitro. On this basis, we proposed our bacteriophage adherence to mucus (BAM) model of immunity. Here, to test this model, we developed a microfluidic device (chip) that emulates a mucosal surface experiencing constant fluid flow and mucin secretion dynamics. Using mucus-producing human cells and Escherichia coli in the chip, we observed similar accumulation and persistence of mucus-adherent T4 phage and nonadherent T4∆hoc phage in the mucus. Nevertheless, T4 phage reduced bacterial colonization of the epithelium >4,000-fold compared with T4∆hoc phage. This suggests that phage adherence to mucus increases encounters with bacterial hosts by some other mechanism. Phages are traditionally thought to be completely dependent on normal diffusion, driven by random Brownian motion, for host contact. We demonstrated that T4 phage particles displayed subdiffusive motion in mucus, whereas T4∆hoc particles displayed normal diffusion. Experiments and modeling indicate that subdiffusive motion increases phage-host encounters when bacterial concentration is low. By concentrating phages in an optimal mucus zone, subdiffusion increases their host encounters and antimicrobial action. Our revised BAM model proposes that the fundamental mechanism of mucosal immunity is subdiffusion resulting from adherence to mucus. These findings suggest intriguing possibilities for engineering phages to manipulate and personalize the mucosal microbiome.

How Many Parasites Species a Frog Might Have? Determinants of Parasite Diversity in South American Anurans.

PubMed

Campião, Karla Magalhães; Ribas, Augusto Cesar de Aquino; Morais, Drausio Honorio; da Silva, Reinaldo José; Tavares, Luiz Eduardo Roland

2015-01-01

There is an increasing interest in unveiling the dynamics of parasite infection. Understanding the interaction patterns, and determinants of host-parasite association contributes to filling knowledge gaps in both community and disease ecology. Despite being targeted as a relevant group for conservation efforts, determinants of the association of amphibians and their parasites in broad scales are poorly understood. Here we describe parasite biodiversity in South American amphibians, testing the influence of host body size and geographic range in helminth parasites species richness (PSR). We also test whether parasite diversity is related to hosts' phylogenetic diversity. Results showed that nematodes are the most common anuran parasites. Host-parasite network has a nested pattern, with specialist helminth taxa generally associated with hosts that harbour the richest parasite faunas. Host size is positively correlated with helminth fauna richness, but we found no support for the association of host geographic range and PSR. These results remained consistent after correcting for uneven study effort and hosts' phylogenic correlation. However, we found no association between host and parasite diversity, indicating that more diversified anuran clades not necessarily support higher parasite diversity. Overall, considering both the structure and the determinants of PRS in anurans, we conclude that specialist parasites are more likely to be associated with large anurans, which are the ones harbouring higher PSR, and that the lack of association of PSR with hosts' clade diversification suggests it is strongly influenced by ecological and contemporary constrains.

Staphylococcus aureus pathogenesis in diverse host environments

PubMed Central

Balasubramanian, Divya; Harper, Lamia; Shopsin, Bo; Torres, Victor J.

2017-01-01

Abstract Staphylococcus aureus is an eminent human pathogen that can colonize the human host and cause severe life-threatening illnesses. This bacterium can reside in and infect a wide range of host tissues, ranging from superficial surfaces like the skin to deeper tissues such as in the gastrointestinal tract, heart and bones. Due to its multifaceted lifestyle, S. aureus uses complex regulatory networks to sense diverse signals that enable it to adapt to different environments and modulate virulence. In this minireview, we explore well-characterized environmental and host cues that S. aureus responds to and describe how this pathogen modulates virulence in response to these signals. Lastly, we highlight therapeutic approaches undertaken by several groups to inhibit both signaling and the cognate regulators that sense and transmit these signals downstream. PMID:28104617

Detection of urinary biomarkers in reservoir hosts of Leptospirosis by capillary electrophoresis mass spectrometry

USDA-ARS?s Scientific Manuscript database

Pathogenic leptospires colonize the renal tubules of reservoir hosts of infection and are excreted via urine into the environment. Reservoir hosts include a wide range of domestic and wild animal species and include cattle, dogs and rats which can persistently excrete large numbers of pathogenic lep...

Habitat preference and the evolution of sympatric intersterility groups in the Heterbasidion annosum species complex

Treesearch

M. Garbelotto; W.J. Otrosina; F.W. Cobb; T.D. Bruns

1998-01-01

Populations of the basidiomycete Heterobasidion annosum display varying degrees, of intersterility and differential host specialization. At least three intersterility groups have been formally described, each characterized by a range of "preferred" hosts. It has been hypothesized that processes of host-pathogen compatibility may have been...

Diverse Broad-Host-Range Plasmids from Freshwater Carry Few Accessory Genes

PubMed Central

Sen, Diya; Yano, Hirokazu; Bauer, Matthew L.; Rogers, Linda M.; Van der Auwera, Geraldine A.

2013-01-01

Broad-host-range self-transferable plasmids are known to facilitate bacterial adaptation by spreading genes between phylogenetically distinct hosts. These plasmids typically have a conserved backbone region and a variable accessory region that encodes host-beneficial traits. We do not know, however, how well plasmids that do not encode accessory functions can survive in nature. The goal of this study was to characterize the backbone and accessory gene content of plasmids that were captured from freshwater sources without selecting for a particular phenotype or cultivating their host. To do this, triparental matings were used such that the only required phenotype was the plasmid's ability to mobilize a nonconjugative plasmid. Based on complete genome sequences of 10 plasmids, only 5 carried identifiable accessory gene regions, and none carried antibiotic resistance genes. The plasmids belong to four known incompatibility groups (IncN, IncP-1, IncU, and IncW) and two potentially new groups. Eight of the plasmids were shown to have a broad host range, being able to transfer into alpha-, beta-, and gammaproteobacteria. Because of the absence of antibiotic resistance genes, we resampled one of the sites and compared the proportion of captured plasmids that conferred antibiotic resistance to their hosts with the proportion of such plasmids captured from the effluent of a local wastewater treatment plant. Few of the captured plasmids from either site encoded antibiotic resistance. A high diversity of plasmids that encode no or unknown accessory functions is thus readily found in freshwater habitats. The question remains how the plasmids persist in these microbial communities. PMID:24096417

Life history and biology of Fascioloides magna (Trematoda) and its native and exotic hosts

PubMed Central

Malcicka, Miriama

2015-01-01

Host–parasite interactions are model systems in a wide range of ecological and evolutionary fields and may be utilized for testing numerous theories and hypotheses in terms of both applied and fundamental research. For instance, they are important in terms of studying coevolutionary arms races, species invasions, and in economic terms the health of livestock and humans. Here, I present a comprehensive description of the life history, biogeography, and biology of the giant liver fluke, Fascioloides magna, and both its intermediate and definitive hosts. F. magna is native to North America where it uses several species of freshwater snails (Lymnaeidae) as intermediate hosts and four main species of ungulates as definitive hosts. The fluke has also been introduced into parts of Europe where it is now established in two lymnaeid snail species and three ungulate species. This study gives a comprehensive description of different developmental stages of the fluke in its two host classes, as well as detailed notes on historical and present distributions of F. magna in North America and Europe as well as in its snail and deer hosts (with range maps provided). Aberrant and dead-end hosts are also discussed in detail, and descriptive phylogenies are provided for all of the organisms. I briefly discuss how F. magna represents a model example of multiple-level ecological fitting, a phenomenon not yet described in the empirical literature. Lastly, I explore possible future scenarios for fluke invasion in Europe, where it is currently expanding its range. PMID:25897378

Distribution of O-Acetylated Sialic Acids among Target Host Tissues for Influenza Virus

PubMed Central

Barnard, Karen N.; Ossiboff, Robert J.; Khedri, Zahra; Feng, Kurtis H.; Yu, Hai; Chen, Xi; Varki, Ajit

2017-01-01

ABSTRACT Sialic acids (Sias) are important glycans displayed on the cells and tissues of many different animals and are frequent targets for binding and modification by pathogens, including influenza viruses. Influenza virus hemagglutinins bind Sias during the infection of their normal hosts, while the encoded neuraminidases and/or esterases remove or modify the Sia to allow virion release or to prevent rebinding. Sias naturally occur in a variety of modified forms, and modified Sias can alter influenza virus host tropisms through their altered interactions with the viral glycoproteins. However, the distribution of modified Sia forms and their effects on pathogen-host interactions are still poorly understood. Here we used probes developed from viral Sia-binding proteins to detect O-acetylated (4-O-acetyl, 9-O-acetyl, and 7,9-O-acetyl) Sias displayed on the tissues of some natural or experimental hosts for influenza viruses. These modified Sias showed highly variable displays between the hosts and tissues examined. The 9-O-acetyl (and 7,9-) modified Sia forms were found on cells and tissues of many hosts, including mice, humans, ferrets, guinea pigs, pigs, horses, dogs, as well as in those of ducks and embryonated chicken egg tissues and membranes, although in variable amounts. The 4-O-acetyl Sias were found in the respiratory tissues of fewer animals, being primarily displayed in the horse and guinea pig, but were not detected in humans or pigs. The results suggest that these Sia variants may influence virus tropisms by altering and selecting their cell interactions. IMPORTANCE Sialic acids (Sias) are key glycans that control or modulate many normal cell and tissue functions while also interacting with a variety of pathogens, including many different viruses. Sias are naturally displayed in a variety of different forms, with modifications at several positions that can alter their functional interactions with pathogens. In addition, Sias are often modified or removed by enzymes such as host or pathogen esterases or sialidases (neuraminidases), and Sia modifications can alter those enzymatic activities to impact pathogen infections. Sia chemical diversity in different hosts and tissues likely alters the pathogen-host interactions and influences the outcome of infection. Here we explored the display of 4-O-acetyl, 9-O-acetyl, and 7,9-O-acetyl modified Sia forms in some target tissues for influenza virus infection in mice, humans, birds, guinea pigs, ferrets, swine, horses, and dogs, which encompass many natural and laboratory hosts of those viruses. PMID:28904995

An NMR Study of Microvoids in Polymers

NASA Technical Reports Server (NTRS)

Toy, James; Mattrix, Larry

1996-01-01

An understanding of polymer defect structures, like microvoids in polymeric matrices, is most crucial to their fabrication and application potential. In this project guest atoms are introduced into the microvoids in PMR-15 and NMR is used to determine microvoid sizes and locations. Xenon is a relatively inert probe that would normally not be found naturally in polymer or in NMR probe materials. There are two NMR active Xenon isotopes, Xe-129 and Xe-131. The Xe atom has a very high polarizability, which makes it sensitive to the intracrystalline environment of polymers. Interactions between the Xe atoms and the host matrix perturb and Xe electron cloud, deshielding the nuclei, and thereby expanding the range of the observed NMR chemical shifts. This chemical shift range which may be as large as 5000 ppm, permits subtle structural and chemical effects to be studied with high sensitivity. The Xe-129-NMR line shape has been found to vary in response to changes in the pore symmetry of the framework hosts in Zeolites and Clathrasil compounds. Before exposure to Xe gas, the PMR-15 samples were dried in a vacuum oven at 150 C for 48 hours. The samples were then exposed to Xe gas at 30 psi for 72 hours and sealed in glass tubes with 1 atmosphere of Xenon gas. Xenon gas at 1 atmosphere was used to tune up the spectrometer and to set up the appropriate NMR parameters. A series of spectra were obtained interspersed with applications of vacuum and heating to drive out the adsorbed Xe and determine the role of Xe-Xe interactions in the observed chemical shift.

Wide Host Range and Strong Lytic Activity of Staphylococcus aureus Lytic Phage Stau2▿

PubMed Central

Hsieh, Sue-Er; Lo, Hsueh-Hsia; Chen, Shui-Tu; Lee, Mong-Chuan; Tseng, Yi-Hsiung

2011-01-01

In searching for an alternative antibacterial agent against multidrug-resistant Staphylococcus aureus, we have isolated and characterized a lytic staphylophage, Stau2. It possesses a double-stranded DNA genome estimated to be about 134.5 kb and a morphology resembling that of members of the family Myoviridae. With an estimated latency period of 25 min and a burst size of 100 PFU/infected cell, propagation of Stau2 in liquid culture gave a lysate of ca. 6 × 1010 PFU/ml. It was stable at pH 5 to 13 in normal saline at room temperature for at least 4 weeks and at −85°C for more than 2 years, while 1 × 109 out of 2 × 1012 PFU/ml retained infectivity after 36 months at 4°C. Stau2 could lyse 80% of the S. aureus isolates (164/205) obtained from hospitals in Taiwan, with complete lysis of most of the isolates tested within 3 h; however, it was an S. aureus-specific phage because no lytic infection could be found in the coagulase-negative staphylococci tested. Its host range among S. aureus isolates was wider than that of polyvalent phage K (47%), which can also lyse many other staphylococcal species. Experiments with mice demonstrated that Stau2 could provide 100% protection from lethal infection when a multiplicity of infection of 10 was administered immediately after a challenge with S. aureus S23. Considering these results, Stau2 could be considered at least as a candidate for topical phage therapy or an additive in the food industry. PMID:21148689

Wide host range and strong lytic activity of Staphylococcus aureus lytic phage Stau2.

PubMed

Hsieh, Sue-Er; Lo, Hsueh-Hsia; Chen, Shui-Tu; Lee, Mong-Chuan; Tseng, Yi-Hsiung

2011-02-01

In searching for an alternative antibacterial agent against multidrug-resistant Staphylococcus aureus, we have isolated and characterized a lytic staphylophage, Stau2. It possesses a double-stranded DNA genome estimated to be about 134.5 kb and a morphology resembling that of members of the family Myoviridae. With an estimated latency period of 25 min and a burst size of 100 PFU/infected cell, propagation of Stau2 in liquid culture gave a lysate of ca. 6 × 10(10) PFU/ml. It was stable at pH 5 to 13 in normal saline at room temperature for at least 4 weeks and at -85°C for more than 2 years, while 1 × 10(9) out of 2 × 10(12) PFU/ml retained infectivity after 36 months at 4°C. Stau2 could lyse 80% of the S. aureus isolates (164/205) obtained from hospitals in Taiwan, with complete lysis of most of the isolates tested within 3 h; however, it was an S. aureus-specific phage because no lytic infection could be found in the coagulase-negative staphylococci tested. Its host range among S. aureus isolates was wider than that of polyvalent phage K (47%), which can also lyse many other staphylococcal species. Experiments with mice demonstrated that Stau2 could provide 100% protection from lethal infection when a multiplicity of infection of 10 was administered immediately after a challenge with S. aureus S23. Considering these results, Stau2 could be considered at least as a candidate for topical phage therapy or an additive in the food industry.

Non-specific manipulation of gammarid behaviour by P. minutus parasite enhances their predation by definitive bird hosts.

PubMed

Jacquin, Lisa; Mori, Quentin; Pause, Mickaël; Steffen, Mélanie; Medoc, Vincent

2014-01-01

Trophically-transmitted parasites often change the phenotype of their intermediate hosts in ways that increase their vulnerability to definitive hosts, hence favouring transmission. As a "collateral damage", manipulated hosts can also become easy prey for non-host predators that are dead ends for the parasite, and which are supposed to play no role in transmission strategies. Interestingly, infection with the acanthocephalan parasite Polymorphus minutus has been shown to reduce the vulnerability of its gammarid intermediate hosts to non-host predators, whose presence triggered the behavioural alterations expected to favour trophic transmission to bird definitive hosts. Whilst the behavioural response of infected gammarids to the presence of definitive hosts remains to be investigated, this suggests that trophic transmission might be promoted by non-host predation risk. We conducted microcosm experiments to test whether the behaviour of P. minutus-infected gammarids was specific to the type of predator (i.e. mallard as definitive host and fish as non-host), and mesocosm experiments to test whether trophic transmission to bird hosts was influenced by non-host predation risk. Based on the behaviours we investigated (predator avoidance, activity, geotaxis, conspecific attraction), we found no evidence for a specific fine-tuned response in infected gammarids, which behaved similarly whatever the type of predator (mallard or fish). During predation tests, fish predation risk did not influence the differential predation of mallards that over-consumed infected gammarids compared to uninfected individuals. Overall, our results bring support for a less sophisticated scenario of manipulation than previously expected, combining chronic behavioural alterations with phasic behavioural alterations triggered by the chemical and physical cues coming from any type of predator. Given the wide dispersal range of waterbirds (the definitive hosts of P. minutus), such a manipulation whose efficiency does not depend on the biotic context is likely to facilitate its trophic transmission in a wide range of aquatic environments.

Species coextinctions and the biodiversity crisis.

PubMed

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.

Sequence Diversity, Intersubgroup Relationships, and Origins of the Mouse Leukemia Gammaretroviruses of Laboratory and Wild Mice.

PubMed

Bamunusinghe, Devinka; Naghashfar, Zohreh; Buckler-White, Alicia; Plishka, Ronald; Baliji, Surendranath; Liu, Qingping; Kassner, Joshua; Oler, Andrew J; Hartley, Janet; Kozak, Christine A

2016-04-01

Mouse leukemia viruses (MLVs) are found in the common inbred strains of laboratory mice and in the house mouse subspecies ofMus musculus Receptor usage and envelope (env) sequence variation define three MLV host range subgroups in laboratory mice: ecotropic, polytropic, and xenotropic MLVs (E-, P-, and X-MLVs, respectively). These exogenous MLVs derive from endogenous retroviruses (ERVs) that were acquired by the wild mouse progenitors of laboratory mice about 1 million years ago. We analyzed the genomes of seven MLVs isolated from Eurasian and American wild mice and three previously sequenced MLVs to describe their relationships and identify their possible ERV progenitors. The phylogenetic tree based on the receptor-determining regions ofenvproduced expected host range clusters, but these clusters are not maintained in trees generated from other virus regions. Colinear alignments of the viral genomes identified segmental homologies to ERVs of different host range subgroups. Six MLVs show close relationships to a small xenotropic ERV subgroup largely confined to the inbred mouse Y chromosome.envvariations define three E-MLV subtypes, one of which carries duplications of various sizes, sequences, and locations in the proline-rich region ofenv Outside theenvregion, all E-MLVs are related to different nonecotropic MLVs. These results document the diversity in gammaretroviruses isolated from globally distributedMussubspecies, provide insight into their origins and relationships, and indicate that recombination has had an important role in the evolution of these mutagenic and pathogenic agents. Laboratory mice carry mouse leukemia viruses (MLVs) of three host range groups which were acquired from their wild mouse progenitors. We sequenced the complete genomes of seven infectious MLVs isolated from geographically separated Eurasian and American wild mice and compared them with endogenous germ line retroviruses (ERVs) acquired early in house mouse evolution. We did this because the laboratory mouse viruses derive directly from specific ERVs or arise by recombination between different ERVs. The six distinctively different wild mouse viruses appear to be recombinants, often involving different host range subgroups, and most are related to a distinctive, largely Y-chromosome-linked MLV ERV subtype. MLVs with ecotropic host ranges show the greatest variability with extensive inter- and intrasubtype envelope differences and with homologies to other host range subgroups outside the envelope. The sequence diversity among these wild mouse isolates helps define their relationships and origins and emphasizes the importance of recombination in their evolution. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Host Factors in Ebola Infection.

PubMed

Rasmussen, Angela L

2016-08-31

Ebola virus (EBOV) emerged in West Africa in 2014 to devastating effect, and demonstrated that infection can cause a broad range of severe disease manifestations. As the virus itself was genetically similar to other Zaire ebolaviruses, the spectrum of pathology likely resulted from variable responses to infection in a large and genetically diverse population. This review comprehensively summarizes current knowledge of the host response to EBOV infection, including pathways hijacked by the virus to facilitate replication, host processes that contribute directly to pathogenesis, and host-pathogen interactions involved in subverting or antagonizing host antiviral immunity.

Along for the ride or missing it altogether: exploring the host specificity and diversity of haemogregarines in the Canary Islands.

PubMed

Tomé, Beatriz; Pereira, Ana; Jorge, Fátima; Carretero, Miguel A; Harris, D James; Perera, Ana

2018-03-19

Host-parasite relationships are expected to be strongly shaped by host specificity, a crucial factor in parasite adaptability and diversification. Because whole host communities have to be considered to assess host specificity, oceanic islands are ideal study systems given their simplified biotic assemblages. Previous studies on insular parasites suggest host range broadening during colonization. Here, we investigate the association between one parasite group (haemogregarines) and multiple sympatric hosts (of three lizard genera: Gallotia, Chalcides and Tarentola) in the Canary Islands. Given haemogregarine characteristics and insular conditions, we hypothesized low host specificity and/or occurrence of host-switching events. A total of 825 samples were collected from the three host taxa inhabiting the seven main islands of the Canarian Archipelago, including locations where the different lizards occurred in sympatry. Blood slides were screened to assess prevalence and parasitaemia, while parasite genetic diversity and phylogenetic relationships were inferred from 18S rRNA gene sequences. Infection levels and diversity of haplotypes varied geographically and across host groups. Infections were found in all species of Gallotia across the seven islands, in Tarentola from Tenerife, La Gomera and La Palma, and in Chalcides from Tenerife, La Gomera and El Hierro. Gallotia lizards presented the highest parasite prevalence, parasitaemia and diversity (seven haplotypes), while the other two host groups (Chalcides and Tarentola) harbored one haplotype each, with low prevalence and parasitaemia levels, and very restricted geographical ranges. Host-sharing of the same haemogregarine haplotype was only detected twice, but these rare instances likely represent occasional cross-infections. Our results suggest that: (i) Canarian haemogregarine haplotypes are highly host-specific, which might have restricted parasite host expansion; (ii) haemogregarines most probably reached the Canary Islands in three colonization events with each host genus; and (iii) the high number of parasite haplotypes infecting Gallotia hosts and their restricted geographical distribution suggest co-diversification. These findings contrast with our expectations derived from results on other insular parasites, highlighting how host specificity depends on parasite characteristics and evolutionary history.

Morphological and Molecular Revision of the Genus Ozirhincus (Diptera: Cecidomyiidae)—Long-Snouted Seed-Feeding Gall Midges on Asteraceae

PubMed Central

Dorchin, Netta; Astrin, Jonas J.; Bodner, Levona; Harris, Keith M.

2015-01-01

The Palaearctic gall-midge genus Ozirhincus is unique among the Cecidomyiidae for its morphology and biology. Unlike most other phytophagous gall midges, species in this genus do not induce galls but develop inside achenes of Asteraceae plants. The heads of adults are characterized by an unusually elongate proboscis, the function of which is unclear. Despite a lot of attention from taxonomists in the 19th and early 20th century, a proper revision of the genus has been hindered by complex host associations, the loss of most relevant type material, and the lack of a thorough comparative study of all life stages. The present revision integrated morphological, molecular, and life-history data to clearly define species boundaries within Ozirhincus, and delimit host-plant ranges for each of them. A phylogenetic analysis based on the mitochondrial COI and 16S genes confirmed the validity of four distinct species but did not resolve the relationships among them. All species are oligophages, and some may occur together on the same host plant. Species with wider host-plant ranges have wider European and circum-Mediterranean distribution ranges, whereas species with narrower host ranges are limited to Europe and the Russian Far East. As part of the present work, O. hungaricus is reinstated from synonymy, O. tanaceti is synonymized under O. longicollis, neotypes are designated for O. longicollis and O. millefolii, and a lectotype is designated for O. anthemidis. PMID:26134526

The effect of immunodeficiency on the evolution of virulence: an experimental test with the rodent malaria Plasmodium chabaudi.

PubMed

Barclay, Victoria C; Kennedy, David A; Weaver, Veronika C; Sim, Derek; Lloyd-Smith, James O; Read, Andrew F

2014-08-01

Host immunity plays an important role in the evolution of pathogen virulence and disease emergence. There is increasing theoretical and empirical evidence that enhanced immunity through vaccination may have the unfortunate side effect of selecting for more virulent parasites, but the effect of host immune suppression on pathogen evolution is less clear. Here, we use serial passage experiments in mice to test how immune-suppressed hosts may alter pathogen virulence evolution. We passaged Plasmodium chabaudi through CD4(+) T cell-depleted or control mice every 7 days for 20 weeks and then measured virulence differences during infection of immunologically normal mice. We found that those parasites that had been selected through CD4(+) T cell-depleted mice were more virulent than parasites selected through control mice. Virulence increases during serial passage are believed to be caused by pathogen adaptation to the passage host. These data suggest that immune-suppressed hosts could provide a within-host environment that lowers the barrier to parasite adaptation and promotes the evolution of virulence.

The interdependencies of viral load, the innate immune response, and clinical outcome in children presenting to the emergency department with respiratory syncytial virus-associated bronchiolitis

PubMed Central

Mei, Minghua; Mehta, Reena

2017-01-01

Respiratory syncytial virus (RSV) causes significant infant morbidity and mortality. For decades severe RSV-induced disease was thought to result from an uncontrolled host response to viral replication, but recent work suggests that a strong innate immune response early in infection is protective. To shed light on host-virus interactions and the viral determinants of disease, copy numbers of five RSV genes (NS1, NS2, N, G, F) were measured by quantitative real-time polymerase chain reaction (qPCR) in nasal wash samples from children with RSV-associated bronchiolitis. Correlations were sought with host cytokines/chemokines and biomarkers. Associations with disposition from the emergency department (hospitalized or sent home) and pulse oximetry O2 saturation levels were also sought. Additionally, RNase P copy number was measured and used to normalize nasal wash data. RSV gene copy numbers were found to significantly correlate with both cytokine/chemokine and biomarker levels; and RNase P-normalized viral gene copy numbers (NS1, NS2, N and G) were significantly higher in infants with less severe disease. Moreover, three of the normalized viral gene copy numbers (NS1, NS2, and N) correlated significantly with arterial O2 saturation levels. The data support a model where a higher viral load early in infection can promote a robust innate immune response that protects against progression into hypoxic RSV-induced lower respiratory tract illness. PMID:28267794

The interdependencies of viral load, the innate immune response, and clinical outcome in children presenting to the emergency department with respiratory syncytial virus-associated bronchiolitis.

PubMed

Piedra, Felipe-Andrés; Mei, Minghua; Avadhanula, Vasanthi; Mehta, Reena; Aideyan, Letisha; Garofalo, Roberto P; Piedra, Pedro A

2017-01-01

Respiratory syncytial virus (RSV) causes significant infant morbidity and mortality. For decades severe RSV-induced disease was thought to result from an uncontrolled host response to viral replication, but recent work suggests that a strong innate immune response early in infection is protective. To shed light on host-virus interactions and the viral determinants of disease, copy numbers of five RSV genes (NS1, NS2, N, G, F) were measured by quantitative real-time polymerase chain reaction (qPCR) in nasal wash samples from children with RSV-associated bronchiolitis. Correlations were sought with host cytokines/chemokines and biomarkers. Associations with disposition from the emergency department (hospitalized or sent home) and pulse oximetry O2 saturation levels were also sought. Additionally, RNase P copy number was measured and used to normalize nasal wash data. RSV gene copy numbers were found to significantly correlate with both cytokine/chemokine and biomarker levels; and RNase P-normalized viral gene copy numbers (NS1, NS2, N and G) were significantly higher in infants with less severe disease. Moreover, three of the normalized viral gene copy numbers (NS1, NS2, and N) correlated significantly with arterial O2 saturation levels. The data support a model where a higher viral load early in infection can promote a robust innate immune response that protects against progression into hypoxic RSV-induced lower respiratory tract illness.

Inhibition of Bombyx mori nuclear polyhedrosis virus (NPV) replication by the putative DNA helicase gene of Autographa californica NPV.

PubMed Central

Kamita, S G; Maeda, S

1993-01-01

Coinfection of Bombyx mori nuclear polyhedrosis virus (BmNPV) with Autographa californica NPV (AcNPV) in the BmNPV-permissive BmN cell line resulted in the complete inhibition of BmNPV replication. Coinfected BmN cells exhibited an atypical cytopathic effect (CPE) and synthesis of viral and host proteins was dramatically attenuated by 5 h postinfection (p.i.) and nearly completely blocked by 24 h p.i. Viral transcription, however, appeared to occur normally during both early (5-h-p.i.) and late (24-h-p.i.) stages of infection. Superinfection of BmN cells with AcNPV at 5 and 12 h post-BmNPV infection resulted in limited inhibition of BmNPV replication. BmN cells singly infected with AcNPV also showed similar CPE, premature inhibition of viral and host protein synthesis, and apparently normal viral transcription. BmNPV replication occurred normally following coinfection of BmNPV and eh2-AcNPV, an AcNPV mutant identical to AcNPV except for a 572-bp region in its putative DNA helicase gene originating from BmNPV (S. Maeda, S. G. Kamita, and A. Kondo, J. Virol. 67:6234-6238, 1993). Furthermore, atypical CPE and premature attenuation of host and viral protein synthesis were not observed. These results indicated that the inhibition of BmNPV replication was caused either directly or indirectly at the translational level by the putative AcNPV DNA helicase gene. Images PMID:7690422

Management Options for Control of a Stunt and Needle Nematode in Southern Forest Nurseries

Treesearch

Michelle M. Cram; Stephen W. Fraedrich

2005-01-01

Crop rotation and fallow are management options that can be used to control plant parasitic nematodes in forest tree nurseries. Before these options can be put into practice, it is important to determine the host range and survivability under fallow of the parasitic nematode to be controlled. The results of host range tests on a needle nematode (Longidorus...

Methionine transport in the malaria parasite Plasmodium falciparum.

PubMed

Cobbold, Simon A; Martin, Rowena E; Kirk, Kiaran

2011-01-01

The intraerythrocytic malaria parasite, Plasmodium falciparum, derives amino acids from the digestion of host cell haemoglobin. However, it also takes up amino acids from the extracellular medium. Isoleucine is absent from adult human haemoglobin and an exogenous source of isoleucine is essential for parasite growth. An extracellular source of methionine is also important for the normal growth of at least some parasite strains. In this study we have characterised the uptake of methionine by P. falciparum-infected human erythrocytes, and by parasites functionally isolated from their host cells by saponin-permeabilization of the erythrocyte membrane. Infected erythrocytes take up methionine much faster than uninfected erythrocytes, with the increase attributable to the flux of this amino acid via the New Permeability Pathways induced by the parasite in the erythrocyte membrane. Having entered the infected cell, methionine is taken up by the intracellular parasite via a saturable, temperature-dependent process that is independent of ATP, Na(+) and H(+). Substrate competition studies, and comparison of the transport of methionine with that of isoleucine and leucine, yielded results consistent with the hypothesis that the parasite has at its surface one or more transporters which mediate the flux into and out of the parasite of a broad range of neutral amino acids. These transporters function most efficiently when exchanging one neutral amino acid for another, thus providing a mechanism whereby the parasite is able to import important exogenous amino acids in exchange for surplus neutral amino acids liberated from the digestion of host cell haemoglobin. Copyright © 2010 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reines, Amy E.; Volonteri, Marta, E-mail: reines@umich.edu

Scaling relations between central black hole (BH) mass and host galaxy properties are of fundamental importance to studies of BH and galaxy evolution throughout cosmic time. Here we investigate the relationship between BH mass and host galaxy total stellar mass using a sample of 262 broad-line active galactic nuclei (AGNs) in the nearby universe (z < 0.055), as well as 79 galaxies with dynamical BH masses. The vast majority of our AGN sample is constructed using Sloan Digital Sky Survey spectroscopy and searching for Seyfert-like narrow-line ratios and broad Hα emission. BH masses are estimated using standard virial techniques. Wemore » also include a small number of dwarf galaxies with total stellar masses M{sub stellar} ≲ 10{sup 9.5} M{sub ⊙} and a subsample of the reverberation-mapped AGNs. Total stellar masses of all 341 galaxies are calculated in the most consistent manner feasible using color-dependent mass-to-light ratios. We find a clear correlation between BH mass and total stellar mass for the AGN host galaxies, with M{sub BH} ∝ M{sub stellar}, similar to that of early-type galaxies with dynamically detected BHs. However, the relation defined by the AGNs has a normalization that is lower by more than an order of magnitude, with a BH-to-total stellar mass fraction of M{sub BH}/M{sub stellar} ∼ 0.025% across the stellar mass range 10{sup 8} ≤ M{sub stellar}/M{sub ⊙} ≤ 10{sup 12}. This result has significant implications for studies at high redshift and cosmological simulations in which stellar bulges cannot be resolved.« less

Chronically implanted pressure sensors: challenges and state of the field.

PubMed

Yu, Lawrence; Kim, Brian J; Meng, Ellis

2014-10-31

Several conditions and diseases are linked to the elevation or depression of internal pressures from a healthy, normal range, motivating the need for chronic implantable pressure sensors. A simple implantable pressure transduction system consists of a pressure-sensing element with a method to transmit the data to an external unit. The biological environment presents a host of engineering issues that must be considered for long term monitoring. Therefore, the design of such systems must carefully consider interactions between the implanted system and the body, including biocompatibility, surgical placement, and patient comfort. Here we review research developments on implantable sensors for chronic pressure monitoring within the body, focusing on general design requirements for implantable pressure sensors as well as specifications for different medical applications. We also discuss recent efforts to address biocompatibility, efficient telemetry, and drift management, and explore emerging trends.

[Wellness holidays--wholesome wish or one-sided reality].

PubMed

Müller, H; Kaufmann, E L

2001-04-01

The term wellness is widely used in European tourism. The principal observations regarding the wellness industry concern an expanding supply of and an insufficiently researched demand for wellness programs. The quality dimension of wellness services is increasingly becoming the decisive competitive factor. For this reason quality management plays an important role. Market research shows that average 3- to 5-star hotels provide fairly comprehensive wellness facilities. Wellness hotels should therefore specialize in health information, individual care and a wide range of cultural and relaxation programs. Although the same hotel can host cure and wellness guests at the same time, these two segments have to be considered separately when deciding on the marketing strategy. We therefore assume that wellness is pursued solely by 'healthy' people, the prime aim being prevention. 'Normal cure guests' aim to heal their illness.

Invertebrate Iridoviruses: A Glance over the Last Decade

PubMed Central

Özcan, Orhan; Ilter-Akulke, Ayca Zeynep; Scully, Erin D.; Özgen, Arzu

2018-01-01

Members of the family Iridoviridae (iridovirids) are large dsDNA viruses that infect both invertebrate and vertebrate ectotherms and whose symptoms range in severity from minor reductions in host fitness to systemic disease and large-scale mortality. Several characteristics have been useful for classifying iridoviruses; however, novel strains are continuously being discovered and, in many cases, reliable classification has been challenging. Further impeding classification, invertebrate iridoviruses (IIVs) can occasionally infect vertebrates; thus, host range is often not a useful criterion for classification. In this review, we discuss the current classification of iridovirids, focusing on genomic and structural features that distinguish vertebrate and invertebrate iridovirids and viral factors linked to host interactions in IIV6 (Invertebrate iridescent virus 6). In addition, we show for the first time how complete genome sequences of viral isolates can be leveraged to improve classification of new iridovirid isolates and resolve ambiguous relations. Improved classification of the iridoviruses may facilitate the identification of genus-specific virulence factors linked with diverse host phenotypes and host interactions. PMID:29601483

Invertebrate Iridoviruses: A Glance over the Last Decade.

PubMed

İnce, İkbal Agah; Özcan, Orhan; Ilter-Akulke, Ayca Zeynep; Scully, Erin D; Özgen, Arzu

2018-03-30

Members of the family Iridoviridae (iridovirids) are large dsDNA viruses that infect both invertebrate and vertebrate ectotherms and whose symptoms range in severity from minor reductions in host fitness to systemic disease and large-scale mortality. Several characteristics have been useful for classifying iridoviruses; however, novel strains are continuously being discovered and, in many cases, reliable classification has been challenging. Further impeding classification, invertebrate iridoviruses (IIVs) can occasionally infect vertebrates; thus, host range is often not a useful criterion for classification. In this review, we discuss the current classification of iridovirids, focusing on genomic and structural features that distinguish vertebrate and invertebrate iridovirids and viral factors linked to host interactions in IIV6 (Invertebrate iridescent virus 6). In addition, we show for the first time how complete genome sequences of viral isolates can be leveraged to improve classification of new iridovirid isolates and resolve ambiguous relations. Improved classification of the iridoviruses may facilitate the identification of genus-specific virulence factors linked with diverse host phenotypes and host interactions.

Base Composition Differences between Avian Myeloblastosis Virus Transfer RNA and Transfer RNA Isolated from Host Cells

PubMed Central

Randerath, Kurt; Rosenthal, Leonard J.; Zamecnik, Paul C.

1971-01-01

Using a novel chemical tritium derivative method, we have determined the base composition of 4S RNA isolated from an RNA tumor virus, the avian myeloblastosis virus, and from normal and neoplastic host cells. Extensive differences were detected, particularly with respect to the amount of methylated bases in the viral RNA. The viral 4S RNA, which fulfills the criteria for designation as transfer RNA, appears to be derived from a precursor pool that is different from the precursor population of host-cell 4S RNA. These results are discussed in regard to the possible relationship between transfer RNA of avian mycoblastosis virus and cellular transfer RNA. Images PMID:4332019

Differential divergences of obligately insect-pathogenic Entomophthora species from fly and aphid hosts.

PubMed

Jensen, Annette Bruun; Eilenberg, Jørgen; López Lastra, Claudia

2009-11-01

Three DNA regions (ITS 1, LSU rRNA and GPD) of isolates from the insect-pathogenic fungus genus Entomophthora originating from different fly (Diptera) and aphid (Hemiptera) host taxa were sequenced. The results documented a large genetic diversity among the fly-pathogenic Entomophthora and only minor differences among aphid-pathogenic Entomophthora. The evolutionary time of divergence of the fly and the aphid host taxa included cannot account for this difference. The host-driven divergence of Entomophthora, therefore, has been much greater in flies than in aphids. Host-range differences or a recent host shift to aphid are possible explanations.

Survival relative to new and ancestral host plants, phytoplasma infection, and genetic constitution in host races of a polyphagous insect disease vector

PubMed Central

Maixner, Michael; Albert, Andreas; Johannesen, Jes

2014-01-01

Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentiation between the host races. We used a twice repeated, identical nested experimental design to study survival of the vector on alternative hosts and relative to infection status. Survival was tested with Kaplan–Meier analyses, while genetic differentiation between vector populations was quantified with microsatellite allele frequencies. We found significant direct effects of host plant (reduced survival on wrong hosts) and sex (males survive longer than females) in both host races and relative effects of host (nettle animals more affected than bindweed animals) and sex (males more affected than females). Survival of bindweed animals was significantly higher on symptomatic than nonsymptomatic field bindweed, but in the second experiment only. Infection potentially had a positive effect on survival in nettle animals but due to low infection rates the results remain suggestive. Genetic differentiation was not related to survival. Greater negative plant-transfer effect but no negative effect of stolbur in the derived host race suggests preadaptation to the new pathogen/symbiont strain before strong diversifying selection during the specialization process. Physiological maladaptation or failure to accept the ancestral plant will have similar consequences, namely positive assortative mating within host races and a reduction in the likelihood of oviposition on the alternative plant and thus the acquisition of alternative stolbur strains. PMID:25247065

Survival relative to new and ancestral host plants, phytoplasma infection, and genetic constitution in host races of a polyphagous insect disease vector.

PubMed

Maixner, Michael; Albert, Andreas; Johannesen, Jes

2014-08-01

Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentiation between the host races. We used a twice repeated, identical nested experimental design to study survival of the vector on alternative hosts and relative to infection status. Survival was tested with Kaplan-Meier analyses, while genetic differentiation between vector populations was quantified with microsatellite allele frequencies. We found significant direct effects of host plant (reduced survival on wrong hosts) and sex (males survive longer than females) in both host races and relative effects of host (nettle animals more affected than bindweed animals) and sex (males more affected than females). Survival of bindweed animals was significantly higher on symptomatic than nonsymptomatic field bindweed, but in the second experiment only. Infection potentially had a positive effect on survival in nettle animals but due to low infection rates the results remain suggestive. Genetic differentiation was not related to survival. Greater negative plant-transfer effect but no negative effect of stolbur in the derived host race suggests preadaptation to the new pathogen/symbiont strain before strong diversifying selection during the specialization process. Physiological maladaptation or failure to accept the ancestral plant will have similar consequences, namely positive assortative mating within host races and a reduction in the likelihood of oviposition on the alternative plant and thus the acquisition of alternative stolbur strains.

Phytophthora ramorum is a generalist plant pathogen with differences in virulence between isolates from infectious and dead-end hosts

Treesearch

D. Huberli; M. Garbelotto

2011-01-01

Variation in virulence was examined among isolates of Phytophthora ramorum from epidemiologically important or infectious (non-oak) and transmissive dead-end (oak) hosts from North America. Twelve isolates representative of the genetic, geographic and host range of P. ramorum in the western United States were inoculated on...

The role of female search behaviour in determining host plant range in plant feeding insects: a test of the information processing hypothesis

PubMed Central

Janz, N.; Nylin, S.

1997-01-01

Recent theoretical studies have suggested that host range in herbivorous insects may be more restricted by constraints on information processing on the ovipositing females than by trade-offs in larval feeding efficiency. We have investigated if females from polyphagous species have to pay for their ability to localize and evaluate plants from different species with a lower ability to discriminate between conspecific host plants with differences in quality. Females of the monophagous butterflies Polygonia satyrus, Vanessa indica and Inachis io and the polyphagous P. c-album and Cynthia cardui (all in Lepidoptera, Nymphalidae) were given a simultaneous choice of stinging nettles (Urtica dioica) of different quality. In addition, the same choice trial was given to females from two populations of P. c-album with different degrees of specificity. As predicted from the information processing hypothesis, all specialists discriminated significantly against the bad quality nettle, whereas the generalists laid an equal amount of eggs on both types of nettle. There were no corresponding differences between specialist and generalist larvae in their ability to utilize poor quality leaves. Our study therefore suggests that female host-searching behaviour plays an important role in determining host plant range.

The Role of Female Search Behaviour in Determining Host Plant Range in Plant Feeding Insects: A Test of the Information Processing Hypothesis

NASA Astrophysics Data System (ADS)

Janz, Niklas; Nylin, Soren

1997-05-01

Recent theoretical studies have suggested that host range in herbivorous insects may be more restricted by constraints on information processing on the ovipositing females than by trade-offs in larval feeding efficiency. We have investigated if females from polyphagous species have to pay for their ability to localize and evaluate plants from different species with a lower ability to discriminate between conspecific host plants with differences in quality. Females of the monophagous butterflies Polygonia satyrus, Vanessa indica and Inachis io and the polyphagous P. c-album and Cynthia cardui (all in Lepidoptera, Nymphalidae) were given a simultaneous choice of stinging nettles (Urtica dioica) of different quality. In addition, the same choice trial was given to females from two populations of P. c-album with different degrees of specificity. As predicted from the information processing hypothesis, all specialists discriminated significantly against the bad quality nettle, whereas the generalists laid an equal amount of eggs on both types of nettle. There were no corresponding differences between specialist and generalist larvae in their ability to utilize poor quality leaves. Our study therefore suggests that female host-searching behaviour plays an important role in determining host plant range.

Subverting Host Cell P21-Activated Kinase: A Case of Convergent Evolution across Pathogens.

PubMed

John Von Freyend, Simona; Kwok-Schuelein, Terry; Netter, Hans J; Haqshenas, Gholamreza; Semblat, Jean-Philippe; Doerig, Christian

2017-04-21

Intracellular pathogens have evolved a wide range of strategies to not only escape from the immune systems of their hosts, but also to directly exploit a variety of host factors to facilitate the infection process. One such strategy is to subvert host cell signalling pathways to the advantage of the pathogen. Recent research has highlighted that the human serine/threonine kinase PAK, or p21-activated kinase, is a central component of host-pathogen interactions in many infection systems involving viruses, bacteria, and eukaryotic pathogens. PAK paralogues are found in most mammalian tissues, where they play vital roles in a wide range of functions. The role of PAKs in cell proliferation and survival, and their involvement in a number of cancers, is of great interest in the context of drug discovery. In this review we discuss the latest insights into the surprisingly central role human PAK1 plays for the infection by such different infectious disease agents as viruses, bacteria, and parasitic protists. It is our intention to open serious discussion on the applicability of PAK inhibitors for the treatment, not only of neoplastic diseases, which is currently the primary objective of drug discovery research targeting these enzymes, but also of a wide range of infectious diseases.

Studying tumor growth in Drosophila using the tissue allograft method.

PubMed

Rossi, Fabrizio; Gonzalez, Cayetano

2015-10-01

This protocol describes a method to allograft Drosophila larval tissue into adult fly hosts that can be used to assay the tumorigenic potential of mutant tissues. The tissue of interest is dissected, loaded into a fine glass needle and implanted into a host. Upon implantation, nontransformed tissues do not overgrow beyond their normal size, but malignant tumors grow without limit, are invasive and kill the host. By using this method, Drosophila malignant tumors can be transplanted repeatedly, for years, and therefore they can be aged beyond the short life span of flies. Because several hosts can be implanted using different pieces from a single tumor, the method also allows the tumor mass to be increased to facilitate further studies that may require large amounts of tissue (i.e., genomics, proteomics and so on). This method also provides an operational definition of hyperplastic, benign and malignant growth. The injection procedure itself requires only ∼1 d. Tumor development can then be monitored until the death of the implanted hosts.

Candida albicans, the opportunist. A cellular and molecular perspective.

PubMed

Dupont, P F

1995-02-01

Candida albicans causes the majority of opportunistic fungal infections. The yeast's commensualistic relationship with humans enables it, when environmental conditions are favorable, to multiply and replace much of the normal flora. Virulence factors of C. albicans, enabling the organism to adhere to and penetrate host tissues, involve specific molecular interactions between the cells of the fungus and the host. Localized disease, such as oral candidiasis, onychomycosis, and vaginitis, results. These infections are usually limited to surfaces of the host, and can be quickly and successfully controlled by the use of one of the available antifungal agents. Candida albicans infections typically become systemic and life threatening when the host is immunocompromised. Depending on the immune defect in the host, one of the spectrum of Candida diseases can develop. If successful treatment of these patients is to be achieved, modulation of the immune deficit, as well as the use of an appropriate antifungal drug, must become a routine part of therapeutic interventions.

Host-Microbe Interactions in Microgravity: Assessment and Implications

PubMed Central

Foster, Jamie S.; Wheeler, Raymond M.; Pamphile, Regine

2014-01-01

Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing of the microbiomes associated with plants and animals have shown that these interactions are essential for maintaining host health through the regulation of several metabolic and immune responses. Disruptions to various environmental parameters or community characteristics may impact the resiliency of the microbiome, thus potentially driving host-microbe associations towards disease. In this review, we discuss our current understanding of host-microbe interactions in microgravity and assess the impact of this unique environmental stress on the normal physiological and genetic responses of both pathogenic and mutualistic associations. As humans move beyond our biosphere and undergo longer duration space flights, it will be essential to more fully understand microbial fitness in microgravity conditions in order to maintain a healthy homeostasis between humans, plants and their respective microbiomes. PMID:25370197

Host-microbe interactions in microgravity: assessment and implications.

PubMed

Foster, Jamie S; Wheeler, Raymond M; Pamphile, Regine

2014-05-26

Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing of the microbiomes associated with plants and animals have shown that these interactions are essential for maintaining host health through the regulation of several metabolic and immune responses. Disruptions to various environmental parameters or community characteristics may impact the resiliency of the microbiome, thus potentially driving host-microbe associations towards disease. In this review, we discuss our current understanding of host-microbe interactions in microgravity and assess the impact of this unique environmental stress on the normal physiological and genetic responses of both pathogenic and mutualistic associations. As humans move beyond our biosphere and undergo longer duration space flights, it will be essential to more fully understand microbial fitness in microgravity conditions in order to maintain a healthy homeostasis between humans, plants and their respective microbiomes.

The chronicles of Porphyromonas gingivalis: the microbium, the human oral epithelium and their interplay

PubMed Central

Yilmaz, Özlem

2009-01-01

The microbiota of the human oral mucosa consists of a myriad of bacterial species that normally exist in commensal harmony with the host. Porphyromonas gingivalis, an aetiological agent in severe forms of periodontitis (a chronic inflammatory disease), is a prominent component of the oral microbiome and a successful colonizer of the oral epithelium. This Gram-negative anaerobe can also exist within the host epithelium without the existence of overt disease. Gingival epithelial cells, the outer lining of the gingival mucosa, which function as an important part of the innate immune system, are among the first host cells colonized by P. gingivalis. This review describes recent studies implicating the co-existence and intracellular adaptation of the organism in these target host cells. Specifically, recent findings on the putative mechanisms of persistence, intercellular dissemination and opportunism are highlighted. These new findings may also represent an original and valuable model for mechanistic characterization of other successful host-adapted, self-limiting, persistent intracellular bacteria in human epithelial tissues. PMID:18832296

The chronicles of Porphyromonas gingivalis: the microbium, the human oral epithelium and their interplay.

PubMed

Yilmaz, Ozlem

2008-10-01

The microbiota of the human oral mucosa consists of a myriad of bacterial species that normally exist in commensal harmony with the host. Porphyromonas gingivalis, an aetiological agent in severe forms of periodontitis (a chronic inflammatory disease), is a prominent component of the oral microbiome and a successful colonizer of the oral epithelium. This Gram-negative anaerobe can also exist within the host epithelium without the existence of overt disease. Gingival epithelial cells, the outer lining of the gingival mucosa, which function as an important part of the innate immune system, are among the first host cells colonized by P. gingivalis. This review describes recent studies implicating the co-existence and intracellular adaptation of the organism in these target host cells. Specifically, recent findings on the putative mechanisms of persistence, intercellular dissemination and opportunism are highlighted. These new findings may also represent an original and valuable model for mechanistic characterization of other successful host-adapted, self-limiting, persistent intracellular bacteria in human epithelial tissues.

A checklist of macroparasites of Liza haematocheila (Temminck & Schlegel) (Teleostei: Mugilidae)

PubMed Central

Kostadinova, Aneta

2008-01-01

Background The mugilid fish Liza haematocheila (syn. Mugil soiuy), native to the Western North Pacific, provides opportunities to examine the changes of its parasite fauna after its translocation to the Sea of Azov and subsequent establishment in the Black Sea. However, the information on macroparasites of this host in both ranges of its current distribution comes from isolated studies published in difficult-to-access literature sources. Materials and methods Data from 53 publications, predominantly in Chinese, Russian and Ukrainian, were compiled from an extensive search of the literature and the Host-Parasite Database maintained up to 2005 at the Natural History Museum, London. Results The complete checklist of the metazoan parasites of L. haematocheila throughout its distributional range comprises summarised information for 69 nominal species of helminth and ectoparasitic crustacean parasites, from 45 genera and 27 families (370 host-parasite records in total) and includes the name of the parasite species, the area/locality of the host capture, and the author and date of the published record. The taxonomy is updated and the validity of the records and synonymies are critically evaluated. A comparison of the parasite faunas based on the records in the native and introduced/invasive range of L. haematocheila suggests that a large number of parasite species was 'lost' in the new distributional range whereas an even greater number was 'gained'. Conclusion Although the present checklist provides information that will facilitate future studies, the interesting question of macroparasite faunal diversity in L. haematocheila in its natural and introduced/invasive ranges cannot be dealt with the current data because of unreliability associated with the large number of non-documented and questionable records. This stresses the importance of data quality analysis in using host-parasite database and checklist data. PMID:19117506

A checklist of macroparasites of Liza haematocheila (Temminck & Schlegel) (Teleostei: Mugilidae).

PubMed

Kostadinova, Aneta

2008-12-31

The mugilid fish Liza haematocheila (syn. Mugil soiuy), native to the Western North Pacific, provides opportunities to examine the changes of its parasite fauna after its translocation to the Sea of Azov and subsequent establishment in the Black Sea. However, the information on macroparasites of this host in both ranges of its current distribution comes from isolated studies published in difficult-to-access literature sources. Data from 53 publications, predominantly in Chinese, Russian and Ukrainian, were compiled from an extensive search of the literature and the Host-Parasite Database maintained up to 2005 at the Natural History Museum, London. The complete checklist of the metazoan parasites of L. haematocheila throughout its distributional range comprises summarised information for 69 nominal species of helminth and ectoparasitic crustacean parasites, from 45 genera and 27 families (370 host-parasite records in total) and includes the name of the parasite species, the area/locality of the host capture, and the author and date of the published record. The taxonomy is updated and the validity of the records and synonymies are critically evaluated. A comparison of the parasite faunas based on the records in the native and introduced/invasive range of L. haematocheila suggests that a large number of parasite species was 'lost' in the new distributional range whereas an even greater number was 'gained'. Although the present checklist provides information that will facilitate future studies, the interesting question of macroparasite faunal diversity in L. haematocheila in its natural and introduced/invasive ranges cannot be dealt with the current data because of unreliability associated with the large number of non-documented and questionable records. This stresses the importance of data quality analysis in using host-parasite database and checklist data.

Black Hole in Search of a Home

NASA Astrophysics Data System (ADS)

2005-09-01

Astronomers Discover Bright Quasar Without Massive Host Galaxy An international team of astronomers [1] used two of the most powerful astronomical facilities available, the ESO Very Large Telescope (VLT) at Cerro Paranal and the Hubble Space Telescope (HST), to conduct a detailed study of 20 low redshift quasars. For 19 of them, they found, as expected, that these super massive black holes are surrounded by a host galaxy. But when they studied the bright quasar HE0450-2958, located some 5 billion light-years away, they couldn't find evidence for an encircling galaxy. This, the astronomers suggest, may indicate a rare case of collision between a seemingly normal spiral galaxy and a much more exotic object harbouring a very massive black hole. With masses up to hundreds of millions that of the Sun, "super massive" black holes are the most tantalizing objects known. Hiding in the centre of most large galaxies, including our own Milky Way (see ESO PR 26/03), they sometimes manifest themselves by devouring matter they engulf from their surroundings. Shining up to the largest distances, they are then called "quasars" or "QSOs" (for "quasi-stellar objects"), as they had initially been confused with stars. Decades of observations of quasars have suggested that they are always associated with massive host galaxies. However, observing the host galaxy of a quasar is a challenging work, because the quasar is radiating so energetically that its host galaxy is hard to detect in the flare. ESO PR Photo 28a/05 ESO PR Photo 28a/05 Two Quasars with their Host Galaxy [Preview - JPEG: 400 x 760 pix - 82k] [Normal - JPEG: 800 x 1520 pix - 395k] [Full Res - JPEG: 1722 x 3271 pix - 4.0M] Caption: ESO PR Photo 28a/05 shows two examples of quasars from the sample studied by the astronomers, where the host galaxy is obvious. In each case, the quasar is the bright central spot. The host of HE1239-2426 (left), a z=0.082 quasar, displays large spiral arms, while the host of HE1503+0228 (right), having a redshift of 0.135, is more fuzzy and shows only hints of spiral arms. Although these particular objects are rather close to us and constitute therefore easy targets, their host would still be perfectly visible at much higher redshift, including at distances as large as the one of HE0450-2958 (z=0.285). The observations were done with the ACS camera on the HST. ESO PR Photo 28b/05 ESO PR Photo 28b/05 The Quasar without a Home: HE0450-2958 [Preview - JPEG: 400 x 760 pix - 53k] [Normal - JPEG: 800 x 1520 pix - 197k] [Full Res - JPEG: 1718 x 3265 pix - 1.5M] Caption of ESO PR Photo 28b/05: (Left) HST image of the z=0.285 quasar HE0450-2958. No obvious host galaxy centred on the quasar is seen. Only a strongly disturbed and star forming companion galaxy is seen near the top of the image. (Right) Same image shown after applying an efficient image sharpening method known as MCS-deconvolution. In contrast to the usual cases, as the ones shown in ESO PR Photo 28a/05, the quasar is not situated at the centre of an extended host galaxy, but on the edge of a compact structure, whose spectra (see ESO PR Photo 28c/05) show it to be composed of gas ionised by the quasar radiation. This gas may have been captured through a collision with the star-forming galaxy. The star indicated on the figure is a nearby galactic star seen by chance in the field of view. To overcome this problem, the astronomers devised a new and highly efficient strategy. Using ESO's VLT for spectroscopy and HST for imagery, they observed their quasars at the same time as a reference star. Simultaneous observation of a star allowed them to measure at best the shape of the quasar point source on spectra and images, and further to separate the quasar light from the other contribution, i.e. from the underlying galaxy itself. This very powerful image and spectra sharpening method ("MCS deconvolution") was applied to these data in order to detect the finest details of the host galaxy (see e.g. ESO PR 19/03). Using this efficient technique, the astronomers could detect a host galaxy for all but one of the quasars they studied. No stellar environment was found for HE0450-2958, suggesting that if any host galaxy exists, it must either have a luminosity at least six times fainter than expected a priori from the quasar observed luminosity, or a radius smaller than about 300 light-years. Typical radii for quasar host galaxies range between 6,000 and 50,000 light-years, i.e. they are at least 20 to 170 times larger. "With the data we managed to secure with the VLT and the HST, we would have been able to detect a normal host galaxy", says Pierre Magain (Université de Liège, Belgium), lead author of the paper reporting the study. "We must therefore conclude that, contrary to our expectations, this bright quasar is not surrounded by a massive galaxy." Instead, the astronomers detected just besides the quasar a bright cloud of about 2,500 light-years in size, which they baptized "the blob". The VLT observations show this cloud to be composed only of gas ionised by the intense radiation coming from the quasar. It is probably the gas of this cloud which is feeding the supermassive black hole, allowing it to become a quasar. ESO PR Photo 28c/05 ESO PR Photo 28c/05 Spectrum of Quasar HE0450-2958, the Blob and the Companion Galaxy (FORS/VLT) [Preview - JPEG: 400 x 561 pix - 112k] [Normal - JPEG: 800 x 1121 pix - 257k] [HiRes - JPEG: 2332 x 3268 pix - 1.1M] Caption: ESO PR Photo 28c/05 presents the spectra of the three objects indicated in ESO PR Photo 28b/05 as obtained with FORS1 on ESO's Very Large Telescope. The spectrum of the companion galaxy shown on the top panel reveals strong star formation. Thanks to the image sharpening process, it has been possible to separate very well the spectra of the quasar (centre) from that of the blob (bottom). The spectrum of the blob shows exclusively strong narrow emission lines having properties indicative of ionisation by the quasar light. There is no trace of stellar light, down to very faint levels, in the surrounding of the quasar. A strongly perturbed galaxy, showing all signs of a recent collision, is also seen on the HST images 2 arcseconds away (corresponding to about 50,000 light-years), with the VLT spectra showing it to be presently in a state where it forms stars at a frantic rate. "The absence of a massive host galaxy, combined with the existence of the blob and the star-forming galaxy, lead us to believe that we have uncovered a really exotic quasar, says team member Frédéric Courbin (Ecole Polytechnique Fédérale de Lausanne, Switzerland). "There is little doubt that a burst in the formation of stars in the companion galaxy and the quasar itself have been ignited by a collision that must haven taken place about 100 million years ago. What happened to the putative quasar host remains unknown." HE0450-2958 constitutes a challenging case of interpretation. The astronomers propose several possible explanations, that will need to be further investigated and confronted. Has the host galaxy been completely disrupted as a result of the collision? It is hard to imagine how that could happen. Has an isolated black hole captured gas while crossing the disc of a spiral galaxy? This would require very special conditions and would probably not have caused such a tremendous perturbation as is observed in the neighbouring galaxy. Another intriguing hypothesis is that the galaxy harbouring the black hole was almost exclusively made of dark matter. "Whatever the solution of this riddle, the strong observable fact is that the quasar host galaxy, if any, is much too faint", says team member Knud Jahnke (Astrophysikalisches Institut Potsdam, Germany). The report on HE0450-2958 is published in the September 15, 2005 issue of the journal Nature ("Discovery of a bright quasar without a massive host galaxy" by Pierre Magain et al.).

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

USGS Publications Warehouse

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.

Diversity and Hidden Host Specificity of Chytrids infecting Colonial Volvocacean Algae.

PubMed

Van den Wyngaert, Silke; Rojas-Jimenez, Keilor; Seto, Kensuke; Kagami, Maiko; Grossart, Hans-Peter

2018-05-12

Chytrids are zoosporic fungi that play an important, but yet understudied, ecological role in aquatic ecosystems. Many chytrid species have been morphologically described as parasites on phytoplankton. However, the majority of them have rarely been isolated and lack DNA sequence data. In this study we isolated and cultivated three parasitic chytrids, infecting a common volvocacean host species, Yamagishiella unicocca. In order to identify the chytrids, we characterized morphology and life cycle, and analyzed phylogenetic relationships based on 18S and 28S rDNA genes. Host range and specificity of the chytrids was determined by cross infection assays with host strains, characterized by rbcL and ITS markers. We were able to confirm the identity of two chytrid strains as Endocoenobium eudorinae Ingold and Dangeardia mamillata Schröder and described the third chytrid strain as Algomyces stechlinensis gen. et sp. nov. The three chytrids were assigned to novel and phylogenetically distant clades within the phylum Chytridiomycota, each exhibiting different host specificities. By integrating morphological and molecular data of both the parasitic chytrids and their respective host species, we unveiled cryptic host-parasite associations. This study highlights that a high prevalence of (pseudo)cryptic diversity requires molecular characterization of both phytoplankton host and parasitic chytrid to accurately identify and compare host range and specificity, and to study phytoplankton-chytrid interactions in general. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Host Range and Selectivity of the Hemiparasitic Plant Thesium chinense (Santalaceae)

PubMed Central

Suetsugu, Kenji; Kawakita, Atsushi; Kato, Makoto

2008-01-01

Background and Aims Thesium chinense is a hemiparasitic plant that is common in grassland habitats of eastern Asia. Although the physiology of Thesium has been well studied in attempts to control its weedy habit, there have been few ecological investigations of its parasitic life history. Thesium chinense is thought to parasitize species of Poaceae, but evidence remains circumstantial. Methods A vegetation survey was conducted to test whether any plant species occurs significantly more often in plots with T. chinense than expected. In addition, haustorial connections were examined directly by excavating the roots and post-attachment host selectivity was evaluated by comparing the observed numbers of haustoria on different hosts against those expected according to the relative below-ground biomass. Haustorium sizes were also compared among host species. Key Results Only two of the 38 species recorded, Lespedeza juncea and Eragrostis curvula, occurred more often in plots with Thesium than expected. In contrast to this, T. chinense parasitized 22 plant species in 11 families, corresponding to 57·9 % of plant species found at the study site. Haustoria were non-randomly distributed among host species, suggesting that there is some post-attachment host selectivity. Thesium chinense generally preferred the Poaceae, although haustoria formed on the Fabaceae were larger than those on other hosts. Conclusions This is the first quantitative investigation of the host range and selectivity of hemiparasitic plants of the Santalales. The preference for Fabaceae as hosts may be linked to the greater nutrient availability in these nitrogen-fixing plants. PMID:18492736

Phytophthora capsici-tomato interaction features dramatic shifts in gene expression associated with a hemi-biotrophic lifestyle.

PubMed

Jupe, Julietta; Stam, Remco; Howden, Andrew J M; Morris, Jenny A; Zhang, Runxuan; Hedley, Pete E; Huitema, Edgar

2013-06-25

Plant-microbe interactions feature complex signal interplay between pathogens and their hosts. Phytophthora species comprise a destructive group of fungus-like plant pathogens, collectively affecting a wide range of plants important to agriculture and natural ecosystems. Despite the availability of genome sequences of both hosts and microbes, little is known about the signal interplay between them during infection. In particular, accurate descriptions of coordinate relationships between host and microbe transcriptional programs are lacking. Here, we explore the molecular interaction between the hemi-biotrophic broad host range pathogen Phytophthora capsici and tomato. Infection assays and use of a composite microarray allowed us to unveil distinct changes in both P. capsici and tomato transcriptomes, associated with biotrophy and the subsequent switch to necrotrophy. These included two distinct transcriptional changes associated with early infection and the biotrophy to necrotrophy transition that may contribute to infection and completion of the P. capsici lifecycle Our results suggest dynamic but highly regulated transcriptional programming in both host and pathogen that underpin P. capsici disease and hemi-biotrophy. Dynamic expression changes of both effector-coding genes and host factors involved in immunity, suggests modulation of host immune signaling by both host and pathogen. With new unprecedented detail on transcriptional reprogramming, we can now explore the coordinate relationships that drive host-microbe interactions and the basic processes that underpin pathogen lifestyles. Deliberate alteration of lifestyle-associated transcriptional changes may allow prevention or perhaps disruption of hemi-biotrophic disease cycles and limit damage caused by epidemics.

Are parasite richness and abundance linked to prey species richness and individual feeding preferences in fish hosts?

PubMed

Cirtwill, Alyssa R; Stouffer, Daniel B; Poulin, Robert; Lagrue, Clément

2016-01-01

Variations in levels of parasitism among individuals in a population of hosts underpin the importance of parasites as an evolutionary or ecological force. Factors influencing parasite richness (number of parasite species) and load (abundance and biomass) at the individual host level ultimately form the basis of parasite infection patterns. In fish, diet range (number of prey taxa consumed) and prey selectivity (proportion of a particular prey taxon in the diet) have been shown to influence parasite infection levels. However, fish diet is most often characterized at the species or fish population level, thus ignoring variation among conspecific individuals and its potential effects on infection patterns among individuals. Here, we examined parasite infections and stomach contents of New Zealand freshwater fish at the individual level. We tested for potential links between the richness, abundance and biomass of helminth parasites and the diet range and prey selectivity of individual fish hosts. There was no obvious link between individual fish host diet and helminth infection levels. Our results were consistent across multiple fish host and parasite species and contrast with those of earlier studies in which fish diet and parasite infection were linked, hinting at a true disconnect between host diet and measures of parasite infections in our study systems. This absence of relationship between host diet and infection levels may be due to the relatively low richness of freshwater helminth parasites in New Zealand and high host-parasite specificity.

Chemically bonded stationary phases that use synthetic hosts containing aromatic binding clefts: HPLC analysis of nitro-substituted polycyclic aromatic hydrocarbons.

PubMed Central

Zimmerman, S C; Saionz, K W; Zeng, Z

1993-01-01

The synthesis of hosts with improved binding affinities for nitroaromatic guests is described. Association constants for several host-guest complexes were measured in chloroform solution and ranged over three orders of magnitude. Two hosts were covalently linked to silica gel to produce chemically bonded stationary phases for HPLC. The use of these phases for HPLC analysis of nitro-substituted polycyclic aromatic hydrocarbons is discussed. PMID:8433981

Understanding the Host Galaxies of Tidal Disruption Flares

NASA Astrophysics Data System (ADS)

Stone, Nicholas; Generozov, Aleksey; Vasiliev, Eugene; Metzger, Brian

2018-01-01

Recent observations suggest that stellar tidal disruption events (TDE) are strongly overrepresented in rare, post-starburst galaxies. Several dynamical mechanisms have been proposed to elevate their TDE rates, ranging from central stellar overdensities to the presence of supermassive black hole (SMBH) binaries. These, and other, dynamical hypotheses can be disentangled by comparing observations to theoretical predictions for the TDE delay time distribution (DTD). We show that SMBH binaries are a less plausible solution for the post-starburst preference, as they can only reproduce the observed DTD with extensive fine-tuning. The overdensity hypothesis produces a reasonable match to the observed DTD (based on the limited data currently available), provided that the initial stellar density profile created during the starburst, ρ(r), is exceptional in both steepness and normalization. In particular, explaining the post-starburst preference requires ρ∝r‑γ with γ>2.5, i.e. much steeper than the classic Bahcall-Wolf equilibrium profile of γ=7/4. Radial velocity anisotropies also represent a promising explanation, provided that initial anisotropy parameters of β0≈0.5 are sustainable against the radial orbit instability. As the sample of TDEs with well-studied host galaxies grows, the DTD will become a powerful tool for constraining the exceptional dynamical properties of post-starburst galactic nuclei.

U-Th isotopic systematics and ages of carbonate chimneys at the Lost City Hydrothermal Field

NASA Astrophysics Data System (ADS)

Ludwig, K. A.; Shen, C.; Kelley, D. S.; Cheng, H.; Edwards, R.

2009-12-01

The Lost City Hydrothermal Field (LCHF) is a serpentinite-hosted vent field located 15 km west of the spreading axis of the Mid-Atlantic Ridge. In this study, uranium-thorium (U-Th) geochronological techniques have been used to examine the U-Th isotopic systematics of hydrothermal fluids and the 230Th ages of hydrothermally-precipitated carbonate chimneys at the LCHF. Fluid sample analyses indicate that endmember fluids likely contain only 0.0073 ng/g U or less compared to 3.28 ± 0.03 ng/g of U in ambient seawater. For fluid samples with <15 mmol/kg Mg, 232Th concentration is 0.11 to 0.13 pg/g and surrounding seawater concentration average is 0.133 ± 0.016 pg/g. The 230Th/232Th atomic ratios of the vent fluids range from 1 ± 10 to 26 ± 4 ×10-6 and are less than those of seawater. Chimney U is seawater-derived and 238U concentrations range from 1-10 μg/g and the mean chimney corrected initial δ234U is 146.9 ± 0.5, which is not significantly different from the ambient seawater value of 146.5 ± 0.6. Carbonate thorium concentrations range broadly from 0.035-125 ng/g and 230Th/232Th atomic ratios vary from near seawater values of 43 ± 8 × 10-6 up to 530 ± 25 × 10-3. Chimney ages range from 18 ± 6 yrs to 122 ± 12 kyrs. The youngest chimneys are at the intersection of two active, steeply-dipping normal faults that cut the Atlantis Massif; the oldest chimneys are located in the southwest portion of the field. Vent deposits on a steep, fault-bounded wall on the east side of the field are all <4 kyrs old, indicating that mass wasting in this region is relatively recent. Comparison of results to prior age-dating investigations of submarine hydrothermal systems shows that the LCHF is the most long-lived hydrothermal system known to date. It is likely that seismic activity and active faulting within the Atlantis Massif and the Atlantis Fracture Zone, coupled with volumetric expansion of the underlying serpentinized host rocks play major roles in sustaining hydrothermal activity at this site. The longevity of venting at the LCHF may have implications for ecological succession of microorganisms within serpentinite-hosted vent environments.

Some like it hot: evolution and ecology of novel endosymbionts in bat flies of cave-roosting bats (hippoboscoidea, nycterophiliinae).

PubMed

Morse, Solon F; Dick, Carl W; Patterson, Bruce D; Dittmar, Katharina

2012-12-01

We investigated previously unknown associations between bacterial endosymbionts and bat flies of the subfamily Nycterophiliinae (Diptera, Streblidae). Molecular analyses revealed a novel clade of Gammaproteobacteria in Nycterophilia bat flies. This clade was not closely related to Arsenophonus-like microbes found in its sister genus Phalconomus and other bat flies. High population infection rates in Nycterophilia across a wide geographic area, the presence of the symbionts in pupae, the general codivergence between hosts and symbionts, and high AT composition bias in symbiont genes together suggest that this host-symbiont association is obligate in nature and ancient in origin. Some Nycterophilia samples (14.8%) also contained Wolbachia supergroup F (Alphaproteobacteria), suggesting a facultative symbiosis. Likelihood-based ancestral character mapping revealed that, initially, obligate symbionts exhibited association with host-specific Nycterophilia bat flies that use a broad temperature range of cave environments for pupal development. As this mutualism evolved, the temperature range of bat flies narrowed to an exclusive use of hot caves, which was followed by a secondary broadening of the bat flies' host associations. These results suggest that the symbiosis has influenced the environmental tolerance of parasite life history stages. Furthermore, the contingent change to an expanded host range of Nycterophilia bat flies upon narrowing the ecological niche of their developmental stages suggests that altered environmental tolerance across life history stages may be a crucial factor in shaping parasite-host relationships.

Some Like It Hot: Evolution and Ecology of Novel Endosymbionts in Bat Flies of Cave-Roosting Bats (Hippoboscoidea, Nycterophiliinae)

PubMed Central

Morse, Solon F.; Dick, Carl W.; Patterson, Bruce D.

2012-01-01

We investigated previously unknown associations between bacterial endosymbionts and bat flies of the subfamily Nycterophiliinae (Diptera, Streblidae). Molecular analyses revealed a novel clade of Gammaproteobacteria in Nycterophilia bat flies. This clade was not closely related to Arsenophonus-like microbes found in its sister genus Phalconomus and other bat flies. High population infection rates in Nycterophilia across a wide geographic area, the presence of the symbionts in pupae, the general codivergence between hosts and symbionts, and high AT composition bias in symbiont genes together suggest that this host-symbiont association is obligate in nature and ancient in origin. Some Nycterophilia samples (14.8%) also contained Wolbachia supergroup F (Alphaproteobacteria), suggesting a facultative symbiosis. Likelihood-based ancestral character mapping revealed that, initially, obligate symbionts exhibited association with host-specific Nycterophilia bat flies that use a broad temperature range of cave environments for pupal development. As this mutualism evolved, the temperature range of bat flies narrowed to an exclusive use of hot caves, which was followed by a secondary broadening of the bat flies' host associations. These results suggest that the symbiosis has influenced the environmental tolerance of parasite life history stages. Furthermore, the contingent change to an expanded host range of Nycterophilia bat flies upon narrowing the ecological niche of their developmental stages suggests that altered environmental tolerance across life history stages may be a crucial factor in shaping parasite-host relationships. PMID:23042170

Early gut colonizers shape parasite susceptibility and microbiota composition in honey bee workers

PubMed Central

Schwarz, Ryan S.; Moran, Nancy A.; Evans, Jay D.

2016-01-01

Microbial symbionts living within animal guts are largely composed of resident bacterial species, forming communities that often provide benefits to the host. Gut microbiomes of adult honey bees (Apis mellifera) include core residents such as the betaproteobacterium Snodgrassella alvi, alongside transient parasites such as the protozoan Lotmaria passim. To test how these species affect microbiome composition and host physiology, we administered S. alvi and/or L. passim inocula to newly emerged worker bees from four genetic backgrounds (GH) and reared them in normal (within hives) or stressed (protein-deficient, asocial) conditions. Microbiota acquired by normal bees were abundant but quantitatively differed across treatments, indicating treatment-associated dysbiosis. Pretreatment with S. alvi made normal bees more susceptible to L. passim and altered developmental and detoxification gene expression. Stressed bees were more susceptible to L. passim and were depauperate in core microbiota, yet supplementation with S. alvi did not alter this susceptibility. Microbiomes were generally more variable by GH in stressed bees, which also showed opposing and comparatively reduced modulation of gene expression responses to treatments compared with normal bees. These data provide experimental support for a link between altered gut microbiota and increased parasite and pathogen prevalence, as observed from honey bee colony collapse disorder. PMID:27482088

Symbiont interactions with non-native hosts limit the formation of new symbioses.

PubMed

Niepoth, Natalie; Ellers, Jacintha; Henry, Lee M

2018-03-12

Facultative symbionts are common in eukaryotes and can provide their hosts with significant fitness benefits. Despite the advantage of carrying these microbes, they are typically only found in a fraction of the individuals within a population and are often non-randomly distributed among host populations. It is currently unclear why facultative symbionts are only found in certain host individuals and populations. Here we provide evidence for a mechanism to help explain this phenomenon: that when symbionts interact with non-native host genotypes it can limit the horizontal transfer of symbionts to particular host lineages and populations of related hosts. Using reciprocal transfections of the facultative symbiont Hamiltonella defensa into different pea aphid clones, we demonstrate that particular symbiont strains can cause high host mortality and inhibit offspring production when injected into aphid clones other than their native host lineage. However, once established, the symbiont's ability to protect against parasitoids was not influenced by its origin. We then demonstrate that H. defensa is also more likely to establish a symbiotic relationship with aphid clones from a plant-adapted population (biotype) that typically carry H. defensa in nature, compared to clones from a biotype that does not normally carry this symbiont. These results provide evidence that certain aphid lineages and populations of related hosts are predisposed to establishing a symbiotic relationship with H. defensa. Our results demonstrate that host-symbiont genotype interactions represent a potential barrier to horizontal transmission that can limit the spread of symbionts, and adaptive traits they carry, to certain host lineages.

Mycobacterium bovis: A Model Pathogen at the Interface of Livestock, Wildlife, and Humans

PubMed Central

Palmer, Mitchell V.; Thacker, Tyler C.; Waters, W. Ray; Gortázar, Christian; Corner, Leigh A. L.

2012-01-01

Complex and dynamic interactions involving domestic animals, wildlife, and humans create environments favorable to the emergence of new diseases, or reemergence of diseases in new host species. Today, reservoirs of Mycobacterium bovis, the causative agent of tuberculosis in animals, and sometimes humans, exist in a range of countries and wild animal populations. Free-ranging populations of white-tailed deer in the US, brushtail possum in New Zealand, badger in the Republic of Ireland and the United Kingdom, and wild boar in Spain exemplify established reservoirs of M. bovis. Establishment of these reservoirs is the result of factors such as spillover from livestock, translocation of wildlife, supplemental feeding of wildlife, and wildlife population densities beyond normal habitat carrying capacities. As many countries attempt to eradicate M. bovis from livestock, efforts are impeded by spillback from wildlife reservoirs. It will not be possible to eradicate this important zoonosis from livestock unless transmission between wildlife and domestic animals is halted. Such an endeavor will require a collaborative effort between agricultural, wildlife, environmental, and political interests. PMID:22737588

What determines species richness of parasitic organisms? A meta-analysis across animal, plant and fungal hosts.

PubMed

Kamiya, Tsukushi; O'Dwyer, Katie; Nakagawa, Shinichi; Poulin, Robert

2014-02-01

Although a small set of external factors account for much of the spatial variation in plant and animal diversity, the search continues for general drivers of variation in parasite species richness among host species. Qualitative reviews of existing evidence suggest idiosyncrasies and inconsistent predictive power for all proposed determinants of parasite richness. Here, we provide the first quantitative synthesis of the evidence using a meta-analysis of 62 original studies testing the relationship between parasite richness across animal, plant and fungal hosts, and each of its four most widely used presumed predictors: host body size, host geographical range size, host population density, and latitude. We uncover three universal predictors of parasite richness across host species, namely host body size, geographical range size and population density, applicable regardless of the taxa considered and independently of most aspects of study design. A proper match in the primary studies between the focal predictor and both the spatial scale of study and the level at which parasite species richness was quantified (i.e. within host populations or tallied across a host species' entire range) also affected the magnitude of effect sizes. By contrast, except for a couple of indicative trends in subsets of the full dataset, there was no strong evidence for an effect of latitude on parasite species richness; where found, this effect ran counter to the general latitude gradient in diversity, with parasite species richness tending to be higher further from the equator. Finally, the meta-analysis also revealed a negative relationship between the magnitude of effect sizes and the year of publication of original studies (i.e. a time-lag bias). This temporal bias may be due to the increasing use of phylogenetic correction in comparative analyses of parasite richness over time, as this correction yields more conservative effect sizes. Overall, these findings point to common underlying processes of parasite diversification fundamentally different from those controlling the diversity of free-living organisms. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

Interferon in lyssavirus infection.

PubMed

Rieder, Martina; Finke, Stefan; Conzelmann, Karl-Klaus

2012-01-01

Rabies is a zoonosis still claiming more than 50 000 human deaths per year. Typically, human cases are due to infection with rabies virus, the prototype of the Lyssavirus genus, but sporadic cases of rabies-like encephalitis caused by other lyssaviruses have been reported. In contrast to rabies virus, which has an extremely broad host range including many terrestrial warm-blooded animals, rabies-related viruses are associated predominantly with bats and rarely infect terrestrial species. In spite of a very close genetic relationship of rabies and rabies-related viruses, the factors determining the limited host range of rabies-related viruses are not clear. In the past years the importance of viral countermeasures against the host type I interferon system for establishment of an infection became evident. The rabies virus phosphoprotein (P) has emerged as a critical factor required for paralysing the signalling cascades leading to transcriptional activation of interferon genes as well as interferon signalling pathways, thereby limiting expression of antiviral and immune stimulatory genes. Comparative studies would be of interest in order to determine whether differential abilities of the lyssavirus P proteins contribute to the restricted host range of lyssaviruses.

Assessing Probabilistic Risk Assessment Approaches for Insect Biological Control Introductions.

PubMed

Kaufman, Leyla V; Wright, Mark G

2017-07-07

The introduction of biological control agents to new environments requires host specificity tests to estimate potential non-target impacts of a prospective agent. Currently, the approach is conservative, and is based on physiological host ranges determined under captive rearing conditions, without consideration for ecological factors that may influence realized host range. We use historical data and current field data from introduced parasitoids that attack an endemic Lepidoptera species in Hawaii to validate a probabilistic risk assessment (PRA) procedure for non-target impacts. We use data on known host range and habitat use in the place of origin of the parasitoids to determine whether contemporary levels of non-target parasitism could have been predicted using PRA. Our results show that reasonable predictions of potential non-target impacts may be made if comprehensive data are available from places of origin of biological control agents, but scant data produce poor predictions. Using apparent mortality data rather than marginal attack rate estimates in PRA resulted in over-estimates of predicted non-target impact. Incorporating ecological data into PRA models improved the predictive power of the risk assessments.

Assessing Probabilistic Risk Assessment Approaches for Insect Biological Control Introductions

PubMed Central

Kaufman, Leyla V.; Wright, Mark G.

2017-01-01

The introduction of biological control agents to new environments requires host specificity tests to estimate potential non-target impacts of a prospective agent. Currently, the approach is conservative, and is based on physiological host ranges determined under captive rearing conditions, without consideration for ecological factors that may influence realized host range. We use historical data and current field data from introduced parasitoids that attack an endemic Lepidoptera species in Hawaii to validate a probabilistic risk assessment (PRA) procedure for non-target impacts. We use data on known host range and habitat use in the place of origin of the parasitoids to determine whether contemporary levels of non-target parasitism could have been predicted using PRA. Our results show that reasonable predictions of potential non-target impacts may be made if comprehensive data are available from places of origin of biological control agents, but scant data produce poor predictions. Using apparent mortality data rather than marginal attack rate estimates in PRA resulted in over-estimates of predicted non-target impact. Incorporating ecological data into PRA models improved the predictive power of the risk assessments. PMID:28686180

Rapidly expanding genetic diversity and host range of the Circoviridae viral family and other Rep encoding small circular ssDNA genomes

PubMed Central

Delwart, Eric; Li, Linlin

2011-01-01

The genomes of numerous circoviruses and distantly related circular DNA viruses encoding a rolling circle replication initiator protein (Rep) have been characterized from the tissues of mammals, fish, insects, and plants (geminivirus and nanovirus), human and animal feces, in an algae cell, and in diverse environmental samples. We review the genome organization, phylogenetic relationships and initial prevalence studies of cycloviruses, a proposed new genus in the Circoviridae family. Viral fossil rep sequences were also identified integrated on the chromosomes of mammals, frogs, lancelets, crustaceans, mites, gastropods, roundworms, placozoans, hydrozoans, protozoans, land plants, fungi, algae, and phytoplasma bacterias and their plasmids, reflecting their past host range. An ancient origin for viruses with rep-encoding single stranded small circular genomes, predating the diversification of eukaryotes, is discussed. The cellular hosts and pathogenicity of many recently described rep-containing circular genomes remain to be determined. Future studies of the virome of single cell and multi-cellular eukaryotes are likely to further extend the known diversity and host-range of small rep-containing circular viral genomes. PMID:22155583

Prediction of Steps in the Evolution of Variola Virus Host Range

PubMed Central

Smithson, Chad; Purdy, Alex; Verster, Adrian J.; Upton, Chris

2014-01-01

Variola virus, the agent of smallpox, has a severely restricted host range (humans) but a devastatingly high mortality rate. Although smallpox has been eradicated by a World Health Organization vaccination program, knowledge of the evolutionary processes by which human super-pathogens such as variola virus arise is important. By analyzing the evolution of variola and other closely related poxviruses at the level of single nucleotide polymorphisms we detected a hotspot of genome variation within the smallpox ortholog of the vaccinia virus O1L gene, which is known to be necessary for efficient replication of vaccinia virus in human cells. These mutations in the variola virus ortholog and the subsequent loss of the functional gene from camelpox virus and taterapox virus, the two closest relatives of variola virus, strongly suggest that changes within this region of the genome may have played a key role in the switch to humans as a host for the ancestral virus and the subsequent host-range restriction that must have occurred to create the phenotype exhibited by smallpox. PMID:24626337

Prediction of steps in the evolution of variola virus host range.

PubMed

Smithson, Chad; Purdy, Alex; Verster, Adrian J; Upton, Chris

2014-01-01

Variola virus, the agent of smallpox, has a severely restricted host range (humans) but a devastatingly high mortality rate. Although smallpox has been eradicated by a World Health Organization vaccination program, knowledge of the evolutionary processes by which human super-pathogens such as variola virus arise is important. By analyzing the evolution of variola and other closely related poxviruses at the level of single nucleotide polymorphisms we detected a hotspot of genome variation within the smallpox ortholog of the vaccinia virus O1L gene, which is known to be necessary for efficient replication of vaccinia virus in human cells. These mutations in the variola virus ortholog and the subsequent loss of the functional gene from camelpox virus and taterapox virus, the two closest relatives of variola virus, strongly suggest that changes within this region of the genome may have played a key role in the switch to humans as a host for the ancestral virus and the subsequent host-range restriction that must have occurred to create the phenotype exhibited by smallpox.

The Frustrated Host Response to Legionella pneumophila Is Bypassed by MyD88-Dependent Translation of Pro-inflammatory Cytokines

PubMed Central

Asrat, Seblewongel; Dugan, Aisling S.; Isberg, Ralph R.

2014-01-01

Many pathogens, particularly those that require their host for survival, have devised mechanisms to subvert the host immune response in order to survive and replicate intracellularly. Legionella pneumophila, the causative agent of Legionnaires' disease, promotes intracellular growth by translocating proteins into its host cytosol through its type IV protein secretion machinery. At least 5 of the bacterial translocated effectors interfere with the function of host cell elongation factors, blocking translation and causing the induction of a unique host cell transcriptional profile. In addition, L. pneumophila also interferes with translation initiation, by preventing cap-dependent translation in host cells. We demonstrate here that protein translation inhibition by L. pneumophila leads to a frustrated host MAP kinase response, where genes involved in the pathway are transcribed but fail to be translated due to the bacterium-induced protein synthesis inhibition. Surprisingly, few pro-inflammatory cytokines, such as IL-1α and IL-1β, bypass this inhibition and get synthesized in the presence of Legionella effectors. We show that the selective synthesis of these genes requires MyD88 signaling and takes place in both infected cells that harbor bacteria and neighboring bystander cells. Our findings offer a perspective of how host cells are able to cope with pathogen-encoded activities that disrupt normal cellular process and initiate a successful inflammatory response. PMID:25058342

Amphibole incongruent melting under Lithospheric Mantle conditions in spinel peridotites from Balaton area, Hungary

NASA Astrophysics Data System (ADS)

Ntaflos, Theodoros; Abart, Rainer; Bizimis, Michel

2017-04-01

Pliocene alkali basalts from the western Pannonian Basin carry mantle xenoliths comprising hydrous and anhydrous spinel peridotites. We studied coarse and fine grained fertile to depleted spinel lherzolites, spinel harzubrgites and dunites from Szentbékálla, Balaton, in detail, using XRF, EPMA and LA-ICP-MS and MC-ICP-MS techniques. Pliocene alkali basalts containing mantle xenoliths with three major types of textures are widespread in the studied area: fine-grained primary and secondary equigranular, coarse-grained protogranular and transitional between equigranular and protogranular textures. Melt pockets, are common in the studied xenoliths. The shape of several melt pockets resembles euhedral amphibole. Other samples have thin films of intergranular glass attributed to the host basalt infiltration. Calculations have shown that such xenoliths experienced an up to 2.4% host basalt infiltration. The bulk rock Al2O3 and CaO concentrations vary from 0.75 to 4.1 and from 0.9 to 3.6 wt% respectively, and represent residues after variable degrees of partial melting. Using bulk rock major element abundances, the estimated degree of partial melting ranges from 4 to 20%.. The Primitive Mantle normalized clinopyroxene trace element abundances reveal a complicated evolution of the Lithospheric mantle underneath Balaton, which range from partial melting to modal and cryptic metasomatism. Subduction-related melt/fluids and/or infiltration of percolating undersaturated melts could be account for the metasomatic processes. The radiogenic isotopes of Sr, Nd and Hf in clinopyroxene suggest that this metasomatism was a relatively recent event. Textural evidence suggests that the calcite filling up the vesicles in the melt pockets and in veinlets cross-cutting the constituent minerals is of epigenetic nature and not due to carbonatite metasomatism. Mass balance calculations have shown that the bulk composition of the melt pockets is identical to small amphibole relics found as inclusions in second generation clinopyroxene within the melt pockets. Evidently the melt pockets represent amphibole, which have been incongruently molten. The necessary heat for the amphibole breakdown was derived from the host basalt. The estimated time for diffusive Ca exchange between matrix olivine and olivine overgrowth in contact with the melt pockets is very short, ranging between 21 and 200 days, indicating that amphibole breakdown took place immediately before or during the xenolith entrainment in the alkali basalt.

Use of habitat odour by host-seeking insects.

PubMed

Webster, Ben; Cardé, Ring T

2017-05-01

Locating suitable feeding or oviposition sites is essential for insect survival. Understanding how insects achieve this is crucial, not only for understanding the ecology and evolution of insect-host interactions, but also for the development of sustainable pest-control strategies that exploit insects' host-seeking behaviours. Volatile chemical cues are used by foraging insects to locate and recognise potential hosts but in nature these resources usually are patchily distributed, making chance encounters with host odour plumes rare over distances greater than tens of metres. The majority of studies on insect host-seeking have focussed on short-range orientation to easily detectable cues and it is only recently that we have begun to understand how insects overcome this challenge. Recent advances show that insects from a wide range of feeding guilds make use of 'habitat cues', volatile chemical cues released over a relatively large area that indicate a locale where more specific host cues are most likely to be found. Habitat cues differ from host cues in that they tend to be released in larger quantities, are more easily detectable over longer distances, and may lack specificity, yet provide an effective way for insects to maximise their chances of subsequently encountering specific host cues. This review brings together recent advances in this area, discussing key examples and similarities in strategies used by haematophagous insects, soil-dwelling insects and insects that forage around plants. We also propose and provide evidence for a new theory that general and non-host plant volatiles can be used by foraging herbivores to locate patches of vegetation at a distance in the absence of more specific host cues, explaining some of the many discrepancies between laboratory and field trials that attempt to make use of plant-derived repellents for controlling insect pests. © 2016 Cambridge Philosophical Society.

Nonadaptive radiation: Pervasive diet specialization by drift in scale insects?

PubMed

Hardy, Nate B; Peterson, Daniel A; Normark, Benjamin B

2016-10-01

At least half of metazoan species are herbivorous insects. Why are they so diverse? Most herbivorous insects feed on few plant species, and adaptive host specialization is often invoked to explain their diversification. Nevertheless, it is possible that the narrow host ranges of many herbivorous insects are nonadaptive. Here, we test predictions of this hypothesis with comparative phylogenetic analyses of scale insects, a group for which there appear to be few host-use trade-offs that would select against polyphagy, and for which passive wind-dispersal should make host specificity costly. We infer a strong positive relationship between host range and diversification rate, and a marked asymmetry in cladogenetic changes in diet breadth. These results are consonant with a system of pervasive nonadaptive host specialization in which small, drift- and extinction-prone populations are frequently isolated from persistent and polyphagous source populations. They also contrast with the negative relationship between diet breadth and taxonomic diversification that has been estimated in butterflies, a disparity that likely stems from differences in the average costs and benefits of host specificity and generalism in scale insects versus butterflies. Our results indicate the potential for nonadaptive processes to be important to diet-breadth evolution and taxonomic diversification across herbivorous insects. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Evolution of specialization: a phylogenetic study of host range in the red milkweed beetle (Tetraopes tetraophthalmus).

PubMed

Rasmann, Sergio; Agrawal, Anurag A

2011-06-01

Specialization is common in most lineages of insect herbivores, one of the most diverse groups of organisms on earth. To address how and why specialization is maintained over evolutionary time, we hypothesized that plant defense and other ecological attributes of potential host plants would predict the performance of a specialist root-feeding herbivore (the red milkweed beetle, Tetraopes tetraophthalmus). Using a comparative phylogenetic and functional trait approach, we assessed the determinants of insect host range across 18 species of Asclepias. Larval survivorship decreased with increasing phylogenetic distance from the true host, Asclepias syriaca, suggesting that adaptation to plant traits drives specialization. Among several root traits measured, only cardenolides (toxic defense chemicals) correlated with larval survival, and cardenolides also explained the phylogenetic distance effect in phylogenetically controlled multiple regression analyses. Additionally, milkweed species having a known association with other Tetraopes beetles were better hosts than species lacking Tetraopes herbivores, and milkweeds with specific leaf area values (a trait related to leaf function and habitat affiliation) similar to those of A. syriaca were better hosts than species having divergent values. We thus conclude that phylogenetic distance is an integrated measure of phenotypic and ecological attributes of Asclepias species, especially defensive cardenolides, which can be used to explain specialization and constraints on host shifts over evolutionary time.

Regional Survey of Structural Properties and Cementation Patterns of Fault Zones in the Northern Part of the Albuquerque Basin, New Mexico - Implications for Ground-Water Flow

USGS Publications Warehouse

Minor, Scott A.; Hudson, Mark R.

2006-01-01

Motivated by the need to document and evaluate the types and variability of fault zone properties that potentially affect aquifer systems in basins of the middle Rio Grande rift, we systematically characterized structural and cementation properties of exposed fault zones at 176 sites in the northern Albuquerque Basin. A statistical analysis of measurements and observations evaluated four aspects of the fault zones: (1) attitude and displacement, (2) cement, (3) lithology of the host rock or sediment, and (4) character and width of distinctive structural architectural components at the outcrop scale. Three structural architectural components of the fault zones were observed: (1) outer damage zones related to fault growth; these zones typically contain deformation bands, shear fractures, and open extensional fractures, which strike subparallel to the fault and may promote ground-water flow along the fault zone; (2) inner mixed zones composed of variably entrained, disrupted, and dismembered blocks of host sediment; and (3) central fault cores that accommodate most shear strain and in which persistent low- permeability clay-rich rocks likely impede the flow of water across the fault. The lithology of the host rock or sediment influences the structure of the fault zone and the width of its components. Different grain-size distributions and degrees of induration of the host materials produce differences in material strength that lead to variations in width, degree, and style of fracturing and other fault-related deformation. In addition, lithology of the host sediment appears to strongly control the distribution of cement in fault zones. Most faults strike north to north-northeast and dip 55? - 77? east or west, toward the basin center. Most faults exhibit normal slip, and many of these faults have been reactivated by normal-oblique and strike slip. Although measured fault displacements have a broad range, from 0.9 to 4,000 m, most are <100 m, and fault zones appear to have formed mainly at depths less than 1,000 m. Fault zone widths do not exceed 40 m (median width = 15.5 m). The mean width of fault cores (0.1 m) is nearly one order of magnitude less than that of mixed zones (0.75 m) and two orders of magnitude less than that of damage zones (9.7 m). Cements, a proxy for localized flow of ancient ground water, are common along fault zones in the basin. Silica cements are limited to faults that are near and strike north to northwest toward the Jemez volcanic field north of the basin, whereas carbonate fault cements are widely distributed. Coarse sediments (gravel and sand) host the greatest concentrations of cement within fault zones. Cements fill some extension fractures and, to a lesser degree, are concentrated along shear fractures and deformation bands within inner damage zones. Cements are commonly concentrated in mixed zones and inner damage zones on one side of a fault and thus are asymmetrically distributed within a fault zone, but cement does not consistently lie on the basinward side of faults. From observed spatial patterns of asymmetrically distributed fault zone cements, we infer that ancient ground-water flow was commonly localized along, and bounded by, faults in the basin. It is apparent from our study that the Albuquerque Basin contains a high concentration of faults. The geometry of, internal structure of, and cement and clay distribution in fault zones have created and will continue to create considerable heterogeneity of permeability within the basin aquifers. The characteristics and statistical range of fault zone features appear to be predictable and consistent throughout the basin; this predictability can be used in ground-water flow simulations that consider the influence of faults.

Phylogenetic analysis of Deladenus nematodes parasitizing northeastern North American Sirex species.

PubMed

Morris, E Erin; Kepler, Ryan M; Long, Stefan J; Williams, David W; Hajek, Ann E

2013-06-01

The parasitic nematode Deladenus siricidicola is a biological control agent of the invasive woodwasp, Sirex noctilio. Since the discovery of S. noctilio in pine forests of northeastern North America in 2005, a biological control program involving the Kamona strain of D. siricidicola has been under consideration. However, North American pine forests have indigenous Sirex spp. and likely harbor a unique assemblage of associated nematodes. We assessed phylogenetic relationships among native Deladenus spp. in the northeastern United States and the Kamona strain of D. siricidicola. We sequenced three genes (mtCO1, LSU, and ITS) from nematodes extracted from parasitized Sirex spp. collected inside and outside of the range of S. noctilio. Our analyses suggest cospeciation between four North American Sirex spp. and their associated nematode parasites. Within two S. noctilio individuals we found nematodes that we hypothesize are normally associated with Sirex nigricornis. One individual of the native S. nigricornis contained Deladenus normally associated with S. noctilio. We discuss nematode-host fidelity in this system and the potential for non-target impacts of a biological control program using D. siricidicola against S. noctilio. Copyright © 2013 Elsevier Inc. All rights reserved.

Human organoid cultures: transformative new tools for human virus studies.

PubMed

Ramani, Sasirekha; Crawford, Sue E; Blutt, Sarah E; Estes, Mary K

2018-04-01

Studies of human infectious diseases have been limited by the paucity of functional models that mimic normal human physiology and pathophysiology. Recent advances in the development of multicellular, physiologically active organotypic cultures produced from embryonic and pluripotent stem cells, as well as from stem cells isolated from biopsies and surgical specimens are allowing unprecedented new studies and discoveries about host-microbe interactions. Here, we summarize recent developments in the use of organoids for studying human viral pathogens, including intestinal infections with human rotavirus, norovirus, enteroviruses and adenoviruses (intestinal organoids and enteroids), neuronal infections with Zika virus (cerebral organoids) and respiratory infections with respiratory syncytial virus in (lung bud organoids). Biologic discovery of host-specific genetic and epigenetic factors affecting infection, and responses to infection that lead to disease are possible with the use of organoid cultures. Continued development to increase the complexity of these cultures by including components of the normal host tissue microenvironment such as immune cells, blood vessels and microbiome, will facilitate studies on human viral pathogenesis, and advance the development of platforms for pre-clinical evaluation of vaccines, antivirals and therapeutics. Copyright © 2018 Elsevier B.V. All rights reserved.

Toxoplasma aldolase is required for metabolism but dispensable for host-cell invasion.

PubMed

Shen, Bang; Sibley, L David

2014-03-04

Gliding motility and host-cell invasion by apicomplexan parasites depend on cell-surface adhesins that are translocated via an actin-myosin motor beneath the membrane. The current model posits that fructose-1,6-bisphosphate aldolase (ALD) provides a critical link between the cytoplasmic tails of transmembrane adhesins and the actin-myosin motor. Here we tested this model using the Toxoplasma gondii apical membrane protein 1 (TgAMA1), which binds to aldolase in vitro. TgAMA1 cytoplasmic tail mutations that disrupt ALD binding in vitro showed no correlation with host-cell invasion, indicating this interaction is not essential. Furthermore, ALD-depleted parasites were impaired when grown in glucose, yet they showed normal gliding and invasion in glucose-free medium. Depletion of ALD in the presence of glucose led to accumulation of fructose-1,6-bisphosphate, which has been associated with toxicity in other systems. Finally, TgALD knockout parasites and an ALD mutant that specifically disrupts adhesin binding in vitro also supported normal invasion when cultured in glucose-free medium. Taken together, these results suggest that ALD is primarily important for energy metabolism rather than interacting with microneme adhesins, challenging the current model for apicomplexan motility and invasion.

PROTECTION OF MICE AGAINST IRRADIATION AND TETANUS BY HOMOLOGOUS BONE MARROW CELLS FROM HYPERIMMUNIZED DONORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoloff, I.L.; Weiss, A.J.

1963-07-01

Female mice of inbred strains (101 x C3H, BDF, C57B1, Balb/C, C3H, CBA, and LAF) were immunized with 0.2 ml of alum-precipitated tetanus toxoid subcutaneously, followed in 3 weeks by 0.2 ml of fluid toxoid intravenously. Four days after the last injection the marrow was mechanically dispersed and 10- 20 million marrow cells were inoculated intravenously into mice that had received on the previous day a lethal dose of whole-body x irradiation. The LD/sub 96/ for 30 days of each host strain was: BDF, 950 r; LAF, 950 r; 101 x C3H, 900 r; Balb/C, 800 r; C3H, 800 r;more » C57B1, 800 r; and CBA, 700 r. Mice in which isologous bone marrow cells from hyperimmunized donors were transferred to irradiated hosts showed a high degree of protection against irradiation in all strains studied. The percentage of 30-day irradiation survivors follows: C3H, 100%; 101 x C3H, 100%; CBA, 90%; BDF, 90%; Balb/C, 60%; and C57B1, 70%. There were no survivors among groups irradiated but not protected with bone marrow. The percentage of 7- day survivors after toxin challenge for each of 4 different strains receiving isologous cells from hyperimmunized donors ranged between 87 and 100%. Normal mice, similar in weight to the experimental groups (called toxin controls) all died of tetanus within 48 hr of challenge with toxin. Other results showed that homologous disease does not interfere significantly with the in vivo neutralization of tetanus toxin by antitoxin. It was concluded that homologous disease is a clinical entity which, in some donor-host combinations, is associated with a host-vs-graft reaction and, in one strain combination so far tested, is associated with a graft-vshost reaction. The experiments showed that the genetic relation between donor and host is a factor in determining which type of immunologic reaction may occur. (TCO)« less

Sequences in Influenza A Virus PB2 Protein That Determine Productive Infection for an Avian Influenza Virus in Mouse and Human Cell Lines

PubMed Central

Yao, Yongxiu; Mingay, Louise J.; McCauley, John W.; Barclay, Wendy S.

2001-01-01

Reverse genetics was used to analyze the host range of two avian influenza viruses which differ in their ability to replicate in mouse and human cells in culture. Engineered viruses carrying sequences encoding amino acids 362 to 581 of PB2 from a host range variant productively infect mouse and human cells. PMID:11333926

A broad-host range dual-fluorescence reporter system for gene expression analysis in Gram-negative bacteria.

PubMed

Hennessy, Rosanna C; Christiansen, Line; Olsson, Stefan; Stougaard, Peter

2018-01-01

Fluorescence-based reporter systems are valuable tools for studying gene expression dynamics in living cells. Here we describe a dual-fluorescence reporter system carrying the red fluorescent marker mCherry and the blue fluorescent protein EBFP2 enabling the simultaneous analysis of two promoters in broad-host range autofluorescent Gram-negative bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

The challenge of retarding erosion of island biodiversity through phytosanitary measures: An update on the case of Puccinia psidii in Hawai'i

USGS Publications Warehouse

Loope, Lloyd L.; Uchida, Janice Y.

2012-01-01

Most rust fungi are highly host specific, but Puccina psidii has an extremely broad host range within Myrtaceae and gained notoriety with a host jump in its native Brazil from common guava (Psidium guajava) to commercial Eucalyptus plantations. When detected in Hawaiʻi in April 2005, the first invasion outside the neotropics/subtropics, there was immediate concern for ʻōhiʻa (Metrosideros polymorpha). ʻŌhiʻa composes 80% of native forest statewide, providing stable watersheds and habitat for most Hawaiian forest birds and plants. Within months, rust spores spread statewide on wind currents, but ʻōhiʻa was found to be only a minor host, showing very light damage. The primary host was nonnative rose apple (Syzygium jambos), severely affected at a landscape scale, but the epiphytotic subsided as rose apple was largely defoliated or killed within several years. The limited and stable host range in Hawaiʻi (versus elsewhere) led the local conservation community to explore possibilities for excluding new genetic strains of P. psidii. Although national/international phytosanitary standards require strong scientific justification for regulations involving an infraspecific taxonomic level, hopes were buoyed when genetic studies showed no apparent genetic variation/evolution in Hawaiʻi's rust strain. A sophisticated genetic study of P. psidii in its home range is near completion; genetic variation is substantial, and host species strongly influences rust population structure. To prevent introduction of new strains, the Hawaiʻi Department of Agriculture is moving ahead with establishing stringent measures that restrict entry of Myrtaceae into Hawaiʻi. Meanwhile, P. psidii poses a major threat to Myrtaceae biodiversity worldwide.

Within-host evolution of Staphylococcus aureus during asymptomatic carriage.

PubMed

Golubchik, Tanya; Batty, Elizabeth M; Miller, Ruth R; Farr, Helen; Young, Bernadette C; Larner-Svensson, Hanna; Fung, Rowena; Godwin, Heather; Knox, Kyle; Votintseva, Antonina; Everitt, Richard G; Street, Teresa; Cule, Madeleine; Ip, Camilla L C; Didelot, Xavier; Peto, Timothy E A; Harding, Rosalind M; Wilson, Daniel J; Crook, Derrick W; Bowden, Rory

2013-01-01

Staphylococcus aureus is a major cause of healthcare associated mortality, but like many important bacterial pathogens, it is a common constituent of the normal human body flora. Around a third of healthy adults are carriers. Recent evidence suggests that evolution of S. aureus during nasal carriage may be associated with progression to invasive disease. However, a more detailed understanding of within-host evolution under natural conditions is required to appreciate the evolutionary and mechanistic reasons why commensal bacteria such as S. aureus cause disease. Therefore we examined in detail the evolutionary dynamics of normal, asymptomatic carriage. Sequencing a total of 131 genomes across 13 singly colonized hosts using the Illumina platform, we investigated diversity, selection, population dynamics and transmission during the short-term evolution of S. aureus. We characterized the processes by which the raw material for evolution is generated: micro-mutation (point mutation and small insertions/deletions), macro-mutation (large insertions/deletions) and the loss or acquisition of mobile elements (plasmids and bacteriophages). Through an analysis of synonymous, non-synonymous and intergenic mutations we discovered a fitness landscape dominated by purifying selection, with rare examples of adaptive change in genes encoding surface-anchored proteins and an enterotoxin. We found evidence for dramatic, hundred-fold fluctuations in the size of the within-host population over time, which we related to the cycle of colonization and clearance. Using a newly-developed population genetics approach to detect recent transmission among hosts, we revealed evidence for recent transmission between some of our subjects, including a husband and wife both carrying populations of methicillin-resistant S. aureus (MRSA). This investigation begins to paint a picture of the within-host evolution of an important bacterial pathogen during its prevailing natural state, asymptomatic carriage. These results also have wider significance as a benchmark for future systematic studies of evolution during invasive S. aureus disease.

Assessing Global Transcriptome Changes in Response to South African Cassava Mosaic Virus [ZA-99] Infection in Susceptible Arabidopsis thaliana.

PubMed

Pierce, Erica J; Rey, M E Chrissie

2013-01-01

In susceptible plant hosts, co-evolution has favoured viral strategies to evade host defenses and utilize resources to their own benefit. The degree of manipulation of host gene expression is dependent on host-virus specificity and certain abiotic factors. In order to gain insight into global transcriptome changes for a geminivirus pathosystem, South African cassava mosaic virus [ZA:99] and Arabidopsis thaliana, 4×44K Agilent microarrays were adopted. After normalization, a log2 fold change filtering of data (p<0.05) identified 1,743 differentially expressed genes in apical leaf tissue. A significant increase in differential gene expression over time correlated with an increase in SACMV accumulation, as virus copies were 5-fold higher at 24 dpi and 6-fold higher at 36 dpi than at 14 dpi. Many altered transcripts were primarily involved in stress and defense responses, phytohormone signalling pathways, cellular transport, cell-cycle regulation, transcription, oxidation-reduction, and other metabolic processes. Only forty-one genes (2.3%) were shown to be continuously expressed across the infection period, indicating that the majority of genes were transient and unique to a particular time point during infection. A significant number of pathogen-responsive genes were suppressed during the late stages of pathogenesis, while during active systemic infection (14 to 24 dpi), there was an increase in up-regulated genes in several GO functional categories. An adaptive response was initiated to divert energy from growth-related processes to defense, leading to disruption of normal biological host processes. Similarities in cell-cycle regulation correlated between SACMV and Cabbage leaf curl virus (CaLCuV), but differences were also evident. Differences in gene expression between the two geminiviruses clearly demonstrated that, while some global transcriptome responses are generally common in plant virus infections, temporal host-specific interactions are required for successful geminivirus infection. To our knowledge this is the first geminivirus microarray study identifying global differentially expressed transcripts at 3 time points.

Assessing Global Transcriptome Changes in Response to South African Cassava Mosaic Virus [ZA-99] Infection in Susceptible Arabidopsis thaliana

PubMed Central

Pierce, Erica J.; Rey, M. E. Chrissie

2013-01-01

In susceptible plant hosts, co-evolution has favoured viral strategies to evade host defenses and utilize resources to their own benefit. The degree of manipulation of host gene expression is dependent on host-virus specificity and certain abiotic factors. In order to gain insight into global transcriptome changes for a geminivirus pathosystem, South African cassava mosaic virus [ZA:99] and Arabidopsis thaliana, 4×44K Agilent microarrays were adopted. After normalization, a log2 fold change filtering of data (p<0.05) identified 1,743 differentially expressed genes in apical leaf tissue. A significant increase in differential gene expression over time correlated with an increase in SACMV accumulation, as virus copies were 5-fold higher at 24 dpi and 6-fold higher at 36 dpi than at 14 dpi. Many altered transcripts were primarily involved in stress and defense responses, phytohormone signalling pathways, cellular transport, cell-cycle regulation, transcription, oxidation-reduction, and other metabolic processes. Only forty-one genes (2.3%) were shown to be continuously expressed across the infection period, indicating that the majority of genes were transient and unique to a particular time point during infection. A significant number of pathogen-responsive genes were suppressed during the late stages of pathogenesis, while during active systemic infection (14 to 24 dpi), there was an increase in up-regulated genes in several GO functional categories. An adaptive response was initiated to divert energy from growth-related processes to defense, leading to disruption of normal biological host processes. Similarities in cell-cycle regulation correlated between SACMV and Cabbage leaf curl virus (CaLCuV), but differences were also evident. Differences in gene expression between the two geminiviruses clearly demonstrated that, while some global transcriptome responses are generally common in plant virus infections, temporal host-specific interactions are required for successful geminivirus infection. To our knowledge this is the first geminivirus microarray study identifying global differentially expressed transcripts at 3 time points. PMID:23826319

Hyperparasitism in a Generalist Ectoparasitic Pupal Parasitoid, Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae), on Its Own Conspecifics: When the Lack of Resource Lead to Cannibalism.

PubMed

Chen, Wei; He, Zhang; Ji, Xiao-Li; Tang, Si-Ting; Hu, Hao-Yuan

2015-01-01

Hyperparasitism is a normal behavior of parasitoids, which often happens among species. Conspecific hyperparasitism, such as some kinds of heteronomous hyperparasitic behaviors, has been only reported in some species belonging to Aphelinidae. In this article, the conspecific hyperparasitism of Pachycrepoideus vindemmiae (Pteromalidae) is reported, with Drosophila puparia as hosts. Hosts were exposed to P. vindemmiae females twice to parasitism with nine, twelve, and fifteen day intervals between the two exposures. None of the infested hosts emerged more than one offspring, and emergence of parasitoid offspring occurred in two obvious events, synchronously with the exposure time intervals, which suggested that offspring emerging during the first and second events would come from the primary and secondary parasitoids, respectively, and the inference with the developmental duration of offspring also indicated this. With two P. vindemmiae strains that could be identified by a simple sequence repeat marker, the above speculation of the origin of those offspring emerging during the two events was confirmed. Dissection of hosts exposed twice revealed a cannibalism behavior of larvae from the secondary foundresses on the primary conspecific pupae. Our results suggested a conspecific hyperparasitism behavior of the secondary parasitoids on the primary conspecifics. Measures showed a reduced body size for the adults from the conspecific hyperparasitism. Foundresses from the conspecific hyperparasitism had less fitness variables than those from primary parasitism, with shorter longevity, less life time fecundity, lower values of infestation degree, and lower success rate of parasitism. However, when the parasitoids from the conspecific hyperparasitism met healthy Drosophila puparia, their offspring would recover to normal size. Frequency of the conspecific hyperparasitism behavior enhanced with the decreasing of proportion of healthy hosts in the oviposition patch. The conspecific hyperparasitism of P. vindemmiae on the primary conspecifics would be helpful to last the population when healthy hosts are absent in the oviposition patch.

Hyperparasitism in a Generalist Ectoparasitic Pupal Parasitoid, Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae), on Its Own Conspecifics: When the Lack of Resource Lead to Cannibalism

PubMed Central

Chen, Wei; He, Zhang; Ji, Xiao-Li; Tang, Si-Ting; Hu, Hao-Yuan

2015-01-01

Hyperparasitism is a normal behavior of parasitoids, which often happens among species. Conspecific hyperparasitism, such as some kinds of heteronomous hyperparasitic behaviors, has been only reported in some species belonging to Aphelinidae. In this article, the conspecific hyperparasitism of Pachycrepoideus vindemmiae (Pteromalidae) is reported, with Drosophila puparia as hosts. Hosts were exposed to P. vindemmiae females twice to parasitism with nine, twelve, and fifteen day intervals between the two exposures. None of the infested hosts emerged more than one offspring, and emergence of parasitoid offspring occurred in two obvious events, synchronously with the exposure time intervals, which suggested that offspring emerging during the first and second events would come from the primary and secondary parasitoids, respectively, and the inference with the developmental duration of offspring also indicated this. With two P. vindemmiae strains that could be identified by a simple sequence repeat marker, the above speculation of the origin of those offspring emerging during the two events was confirmed. Dissection of hosts exposed twice revealed a cannibalism behavior of larvae from the secondary foundresses on the primary conspecific pupae. Our results suggested a conspecific hyperparasitism behavior of the secondary parasitoids on the primary conspecifics. Measures showed a reduced body size for the adults from the conspecific hyperparasitism. Foundresses from the conspecific hyperparasitism had less fitness variables than those from primary parasitism, with shorter longevity, less life time fecundity, lower values of infestation degree, and lower success rate of parasitism. However, when the parasitoids from the conspecific hyperparasitism met healthy Drosophila puparia, their offspring would recover to normal size. Frequency of the conspecific hyperparasitism behavior enhanced with the decreasing of proportion of healthy hosts in the oviposition patch. The conspecific hyperparasitism of P. vindemmiae on the primary conspecifics would be helpful to last the population when healthy hosts are absent in the oviposition patch. PMID:25909476

Population differences in host use by a seed-beetle: local adaptation, phenotypic plasticity and maternal effects.

PubMed

Amarillo-Suárez, Angela R; Fox, Charles W

2006-11-01

For insects that develop inside discrete hosts, both host size and host quality constrain offspring growth, influencing the evolution of body size and life history traits. Using a two-generation common garden experiment, we quantified the contribution of maternal and rearing hosts to differences in growth and life history traits between populations of the seed-feeding beetle Stator limbatus that use a large-seeded host, Acacia greggii, and a small-seeded host, Pseudosamanea guachapele. Populations differed genetically for all traits when beetles were raised in a common garden. Contrary to expectations from the local adaptation hypothesis, beetles from all populations were larger, developed faster and had higher survivorship when reared on seeds of A. greggii (the larger host), irrespective of their native host. We observed two host plant-mediated maternal effects: offspring matured sooner, regardless of their rearing host, when their mothers were reared on P. guachapele (this was not caused by an effect of rearing host on egg size), and females laid larger eggs on P. guachapele. This is the first study to document plasticity by S. limbatus in response to P. guachapele, suggesting that plasticity is an ancestral trait in S. limbatus that likely plays an important role in diet expansion. Although differences between populations in growth and life history traits are likely adaptations to their host plants, host-associated maternal effects, partly mediated by maternal egg size plasticity, influence growth and life history traits and likely play an important role in the evolution of the breadth of S. limbatus' diet. More generally, phenotypic plasticity mediates the fitness consequences of using novel hosts, likely facilitating colonization of new hosts, but also buffering herbivores from selection post-colonization. Plasticity in response to novel versus normal hosts varied among our study populations such that disentangling the historical role of plasticity in mediating diet evolution requires the consideration of evolutionary history.

Bacterial Serine/Threonine Protein Kinases in Host-Pathogen Interactions*

PubMed Central

Canova, Marc J.; Molle, Virginie

2014-01-01

In bacterial pathogenesis, monitoring and adapting to the dynamically changing environment in the host and an ability to disrupt host immune responses are critical. The virulence determinants of pathogenic bacteria include the sensor/signaling proteins of the serine/threonine protein kinase (STPK) family that have a dual role of sensing the environment and subverting specific host defense processes. STPKs can sense a wide range of signals and coordinate multiple cellular processes to mount an appropriate response. Here, we review some of the well studied bacterial STPKs that are essential virulence factors and that modify global host responses during infection. PMID:24554701

Bacterial serine/threonine protein kinases in host-pathogen interactions.

PubMed

Canova, Marc J; Molle, Virginie

2014-04-04

In bacterial pathogenesis, monitoring and adapting to the dynamically changing environment in the host and an ability to disrupt host immune responses are critical. The virulence determinants of pathogenic bacteria include the sensor/signaling proteins of the serine/threonine protein kinase (STPK) family that have a dual role of sensing the environment and subverting specific host defense processes. STPKs can sense a wide range of signals and coordinate multiple cellular processes to mount an appropriate response. Here, we review some of the well studied bacterial STPKs that are essential virulence factors and that modify global host responses during infection.

The Fleas (Siphonaptera) in Iran: Diversity, Host Range, and Medical Importance.

PubMed

Maleki-Ravasan, Naseh; Solhjouy-Fard, Samaneh; Beaucournu, Jean-Claude; Laudisoit, Anne; Mostafavi, Ehsan

2017-01-01

Flea-borne diseases have a wide distribution in the world. Studies on the identity, abundance, distribution and seasonality of the potential vectors of pathogenic agents (e.g. Yersinia pestis, Francisella tularensis, and Rickettsia felis) are necessary tools for controlling and preventing such diseases outbreaks. The improvements of diagnostic tools are partly responsible for an easier detection of otherwise unnoticed agents in the ectoparasitic fauna and as such a good taxonomical knowledge of the potential vectors is crucial. The aims of this study were to make an exhaustive inventory of the literature on the fleas (Siphonaptera) and range of associated hosts in Iran, present their known distribution, and discuss their medical importance. The data were obtained by an extensive literature review related to medically significant fleas in Iran published before 31st August 2016. The flea-host specificity was then determined using a family and subfamily-oriented criteria to further realize and quantify the shared and exclusive vertebrate hosts of fleas among Iran fleas. The locations sampled and reported in the literature were primarily from human habitation, livestock farms, poultry, and rodents' burrows of the 31 provinces of the country. The flea fauna were dominated by seven families, namely the Ceratophyllidae, Leptopsyllidae, Pulicidae, Ctenophthalmidae, Coptopsyllidae, Ischnopsyllidae and Vermipsyllidae. The hosts associated with Iran fleas ranged from the small and large mammals to the birds. Pulicidae were associated with 73% (56/77) of identified host species. Flea-host association analysis indicates that rodents are the common hosts of 5 flea families but some sampling bias results in the reduced number of bird host sampled. Analyses of flea-host relationships at the subfamily level showed that most vertebrates hosted fleas belgonging to 3 subfamilies namely Xenopsyllinae (n = 43), Ctenophthalminae (n = 20) and Amphipsyllinae (n = 17). Meriones persicus was infested by 11 flea subfamilies in the arid, rocky, mountainous regions and Xenopsyllinae were hosted by at least 43 mammal species. These findings place the Persian jird (M. persicus) and the Xenopsyllinae as the major vertebrate and vector hosts of flea-borne diseases in Iran including Yersinia pestis, the etiological agent of plague. We found records of at least seven vector-borne pathogenic agents that can potentially be transmitted by the 117 flea species (or subspecies) of Iran. Herein, we performed a thorough inventary of the flea species and their associated hosts, their medical importance and geographic distribution throughout Iran. This exercise allowed assessing the diversity of flea species with the potential flea-borne agents transmission risk in the country by arranging published data on flea-host associations. This information is a first step for issuing public health policies and rodent-flea control campaigns in Iran as well as those interested in the ecology/epidemiology of flea-borne disease.

Estimating Hantavirus Risk in Southern Argentina: A GIS-Based Approach Combining Human Cases and Host Distribution

PubMed Central

Andreo, Veronica; Neteler, Markus; Rocchini, Duccio; Provensal, Cecilia; Levis, Silvana; Porcasi, Ximena; Rizzoli, Annapaola; Lanfri, Mario; Scavuzzo, Marcelo; Pini, Noemi; Enria, Delia; Polop, Jaime

2014-01-01

We use a Species Distribution Modeling (SDM) approach along with Geographic Information Systems (GIS) techniques to examine the potential distribution of hantavirus pulmonary syndrome (HPS) caused by Andes virus (ANDV) in southern Argentina and, more precisely, define and estimate the area with the highest infection probability for humans, through the combination with the distribution map for the competent rodent host (Oligoryzomys longicaudatus). Sites with confirmed cases of HPS in the period 1995–2009 were mostly concentrated in a narrow strip (~90 km × 900 km) along the Andes range from northern Neuquén to central Chubut province. This area is characterized by high mean annual precipitation (~1,000 mm on average), but dry summers (less than 100 mm), very low percentages of bare soil (~10% on average) and low temperatures in the coldest month (minimum average temperature −1.5 °C), as compared to the HPS-free areas, features that coincide with sub-Antarctic forests and shrublands (especially those dominated by the invasive plant Rosa rubiginosa), where rodent host abundances and ANDV prevalences are known to be the highest. Through the combination of predictive distribution maps of the reservoir host and disease cases, we found that the area with the highest probability for HPS to occur overlaps only 28% with the most suitable habitat for O. longicaudatus. With this approach, we made a step forward in the understanding of the risk factors that need to be considered in the forecasting and mapping of risk at the regional/national scale. We propose the implementation and use of thematic maps, such as the one built here, as a basic tool allowing public health authorities to focus surveillance efforts and normally scarce resources for prevention and control actions in vast areas like southern Argentina. PMID:24424500

Predicting the host range of Nystalea ebalea: secondary plant chemistry and host selection by a surrogate biological control agent of Schinus terebinthifolia

USDA-ARS?s Scientific Manuscript database

The safety of weed biological control depends upon the selection and utilization of the target weed by the agent while causing minimal harm to non-target species. Selection of weed species by biological control agents is determined by the presence of behavioral cues, generally host secondary plant c...

Walking response of the Mediterranean pine engraver, Orthotomicus erosus, to novel plant odors host in a laboratory olfactometer

Treesearch

A. J. Walter; R. C. Venette; S. A. Kells; S. J. Seybold

2010-01-01

When an herbivorous insect enters a new geographic area, it will select host plants based on short and long distance cues. A conifer-feeding bark beetle that has been recently introduced to North America, the Mediterranean pine engraver, Orthotomicus erosus (Wollaston), has a potentially wide host range, especially among members of the Pinaceae....

Understanding Host-Switching by Ecological Fitting

PubMed Central

Araujo, Sabrina B. L.; Braga, Mariana Pires; Brooks, Daniel R.; Agosta, Salvatore J.; Hoberg, Eric P.; von Hartenthal, Francisco W.; Boeger, Walter A.

2015-01-01

Despite the fact that parasites are highly specialized with respect to their hosts, empirical evidence demonstrates that host switching rather than co-speciation is the dominant factor influencing the diversification of host-parasite associations. Ecological fitting in sloppy fitness space has been proposed as a mechanism allowing ecological specialists to host-switch readily. That proposal is tested herein using an individual-based model of host switching. The model considers a parasite species exposed to multiple host resources. Through time host range expansion can occur readily without the prior evolution of novel genetic capacities. It also produces non-linear variation in the size of the fitness space. The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later. The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes. Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process. PMID:26431199

Nightly biting cycles of malaria vectors in a heterogeneous transmission area of eastern Amazonian Brazil

PubMed Central

2013-01-01

Background The biting cycle of anopheline mosquitoes is an important component in the transmission of malaria. Inter- and intraspecific biting patterns of anophelines have been investigated using the number of mosquitoes caught over time to compare general tendencies in host-seeking activity and cumulative catch. In this study, all-night biting catch data from 32 consecutive months of collections in three riverine villages were used to compare biting cycles of the five most abundant vector species using common statistics to quantify variability and deviations of nightly catches from a normal distribution. Methods Three communities were selected for study. All-night human landing catches of mosquitoes were made each month in the peridomestic environment of four houses (sites) for nine consecutive days from April 2003 to November 2005. Host-seeking activities of the five most abundant species that were previously captured infected with Plasmodium falciparum, Plasmodium malariae or Plasmodium vivax, were analysed and compared by measuring the amount of variation in numbers biting per unit time (co-efficient of variation, V), the degree to which the numbers of individuals per unit time were asymmetrical (skewness = g1) and the relative peakedness or flatness of the distribution (kurtosis = g2). To analyse variation in V, g1, and g2 within species and villages, we used mixed model nested ANOVAs (PROC GLM in SAS) with independent variables (sources of variation): year, month (year), night (year X month) and collection site (year X month). Results The biting cycles of the most abundant species, Anopheles darlingi, had the least pronounced biting peaks, the lowest mean V values, and typically non-significant departures from normality in g1 and g2. By contrast, the species with the most sharply defined crepuscular biting peaks, Anopheles marajoara, Anopheles nuneztovari and Anopheles triannulatus, showed high to moderate mean V values and, most commonly, significantly positive skewness (g1) and kurtosis (g2) moments. Anopheles intermedius was usually, but not always, crepuscular in host seeking, and showed moderate mean V values and typically positive skewness and kurtosis. Among sites within villages, significant differences in frequencies of departures from normality (g1 and g2) were detected for An. marajoara and An. darlingi, suggesting that local environments, such as host availability, may affect the shape of biting pattern curves of these two species. Conclusions Analyses of co-efficients of variation, skewness and kurtosis facilitated quantitative comparisons of host-seeking activity patterns that differ among species, sites, villages, and dates. The variable and heterogeneous nightly host-seeking behaviours of the five exophilic vector species contribute to the maintenance of stable malaria transmission in these Amazonian villages. The abundances of An. darlingi and An. marajoara, their propensities to seek hosts throughout the night, and their ability to adapt host-seeking behaviour to local environments, contribute to their impact as the most important of these vector species. PMID:23890413

Morphologies of mid-IR variability-selected AGN host galaxies

NASA Astrophysics Data System (ADS)

Polimera, Mugdha; Sarajedini, Vicki; Ashby, Matthew L. N.; Willner, S. P.; Fazio, Giovanni G.

2018-05-01

We use multi-epoch 3.6 and 4.5 μm data from the Spitzer Extended Deep Survey (SEDS) to probe the AGN population among galaxies to redshifts ˜3 via their mid-IR variability. About 1 per cent of all galaxies in our survey contain varying nuclei, 80 per cent of which are likely to be AGN. Twenty-three per cent of mid-IR variables are also X-ray sources. The mid-IR variables have a slightly greater fraction of weakly disturbed morphologies compared to a control sample of normal galaxies. The increased fraction of weakly distorted hosts becomes more significant when we remove the X-ray emitting AGN, while the frequency of strongly disturbed hosts remains similar to the control galaxy sample. These results suggest that mid-IR variability identifies a unique population of obscured, Compton-thick AGN revealing elevated levels of weak distortion among their host galaxies.

Salt, chloride, bleach, and innate host defense

PubMed Central

Wang, Guoshun; Nauseef, William M.

2015-01-01

Salt provides 2 life-essential elements: sodium and chlorine. Chloride, the ionic form of chlorine, derived exclusively from dietary absorption and constituting the most abundant anion in the human body, plays critical roles in many vital physiologic functions, from fluid retention and secretion to osmotic maintenance and pH balance. However, an often overlooked role of chloride is its function in innate host defense against infection. Chloride serves as a substrate for the generation of the potent microbicide chlorine bleach by stimulated neutrophils and also contributes to regulation of ionic homeostasis for optimal antimicrobial activity within phagosomes. An inadequate supply of chloride to phagocytes and their phagosomes, such as in CF disease and other chloride channel disorders, severely compromises host defense against infection. We provide an overview of the roles that chloride plays in normal innate immunity, highlighting specific links between defective chloride channel function and failures in host defense. PMID:26048979

Gut microbiota in autoimmunity: potential for clinical applications.

PubMed

Kim, Donghyun; Yoo, Seung-Ah; Kim, Wan-Uk

2016-11-01

Microbial habitation in the human body begins immediately after birth, and adults are colonized by microbes outnumbering human cells by a factor of ten. Especially, intestinal track is a living space for diverse microbial species that have coevolved symbiotically. A principal function of the gut microbiota is to protect the host from harmful bacteria and to provide benefits for the host through several mechanisms, including direct competition for limited nutrients, training of host immune systems to recognize specifically foreign materials and conversion of otherwise indigestible food into energy and absorbable nutrients. Therefore, gut dysbiosis, a bacterial imbalance state, is related with the pathogenesis of various host diseases including autoimmune diseases. In the current review, we highlight the importance of gut microbiota in the normal health and autoimmune diseases. We also discuss regulation of gut dysbiosis and future direction for potential clinical applications, including treatment and diagnostics of autoimmune diseases.

Grafting of a Single Donor Myofibre Promotes Hypertrophy in Dystrophic Mouse Muscle

PubMed Central

Boldrin, Luisa; Morgan, Jennifer E.

2013-01-01

Skeletal muscle has a remarkable capability of regeneration following injury. Satellite cells, the principal muscle stem cells, are responsible for this process. However, this regenerative capacity is reduced in muscular dystrophies or in old age: in both these situations, there is a net loss of muscle fibres. Promoting skeletal muscle muscle hypertrophy could therefore have potential applications for treating muscular dystrophies or sarcopenia. Here, we observed that muscles of dystrophic mdx nude host mice that had been acutely injured by myotoxin and grafted with a single myofibre derived from a normal donor mouse exhibited increased muscle area. Transplantation experiments revealed that the hypertrophic effect is mediated by the grafted fibre and does not require either an imposed injury to the host muscle, or the contribution of donor cells to the host muscle. These results suggest the presence of a crucial cross-talk between the donor fibre and the host muscle environment. PMID:23349935

Salt, chloride, bleach, and innate host defense.

PubMed

Wang, Guoshun; Nauseef, William M

2015-08-01

Salt provides 2 life-essential elements: sodium and chlorine. Chloride, the ionic form of chlorine, derived exclusively from dietary absorption and constituting the most abundant anion in the human body, plays critical roles in many vital physiologic functions, from fluid retention and secretion to osmotic maintenance and pH balance. However, an often overlooked role of chloride is its function in innate host defense against infection. Chloride serves as a substrate for the generation of the potent microbicide chlorine bleach by stimulated neutrophils and also contributes to regulation of ionic homeostasis for optimal antimicrobial activity within phagosomes. An inadequate supply of chloride to phagocytes and their phagosomes, such as in CF disease and other chloride channel disorders, severely compromises host defense against infection. We provide an overview of the roles that chloride plays in normal innate immunity, highlighting specific links between defective chloride channel function and failures in host defense. © Society for Leukocyte Biology.

Star formation across galactic environments

NASA Astrophysics Data System (ADS)

Young, Jason

I present here parallel investigations of star formation in typical and extreme galaxies. The typical galaxies are selected to be free of active galactic nuclei (AGN), while the extreme galaxies host quasars (the most luminous class of AGN). These two environments are each insightful in their own way; quasars are among the most violent objects in the universe, literally reshaping their host galaxies, while my sample of AGN-free star-forming galaxies ranges from systems larger than the Milky Way to small galaxies which are forming stars at unsustainably high rates. The current paradigm of galaxy formation and evolution suggests that extreme circumstances are key stepping stones in the assembly of galaxies like our Milky Way. To test this paradigm and fully explore its ramifications, this dual approach is needed. My sample of AGN-free galaxies is drawn from the KPNO International Spectroscopic Survey. This Halpha-selected, volume-limited survey was designed to detect star-forming galaxies without a bias toward continuum luminosity. This type of selection ensures that this sample is not biased toward galaxies that are large or nearby. My work studies the KISS galaxies in the mid- and far-infrared using photometry from the IRAC and MIPS instruments aboard the Spitzer Space Telescope. These infrared bands are particularly interesting for star formation studies because the ultraviolet light from young stars is reprocessed into thermal emission in the far-infrared (24mum MIPS) by dust and into vibrational transitions features in the mid-infrared (8.0mum IRAC) by polycyclic aromatic hydrocarbons (PAHs). The work I present here examines the efficiencies of PAH and thermal dust emission as tracers of star-formation rates over a wide range of galactic stellar masses. I find that the efficiency of PAH as a star-formation tracer varies with galactic stellar mass, while thermal dust has a highly variable efficiency that does not systematically depend on galactic stellar mass. Complementing this study of normal star-forming galaxies, my study of quasar host galaxies utilizes narrow- and medium-band images of eight Palomar-Green (PG) quasars from the WFPC2 and NICMOS instruments aboard the Hubble Space Telescope. Using images of a point-spread function (PSF) star in the same filters, I subtract the PSF of the quasar from each of the target images. The residual light images clearly show the host galaxies of the respective quasars. The narrow-band images were chosen to be centered on the Hbeta, [O II ], [O III], and Paalpha emission lines, allowing the use of line ratios and luminosities to create extinction and star formation maps. Additionally, I utilize the line-ratio maps to distinguish AGN-powered line emission from star formation powered line emission with line-diagnostic diagrams. I find star formation in each of the eight quasar host galaxies in my study. The bulk star-formation rates are lower than expected, suggesting that quasar host galaxies may be dynamically more advanced than previously believed. Seven of the eight quasar host galaxies in this study have higher-than-typical mass-specific star-formation rates. Additionally, I see evidence of shocked gas, supporting the hypotheses presented in earlier works that suggest that AGN activity quenches star formation in its host galaxy by disrupting its gas reservoir.

Tourmaline occurrences within the Penamacor-Monsanto granitic pluton and host-rocks (Central Portugal): genetic implications of crystal-chemical and isotopic features

NASA Astrophysics Data System (ADS)

da Costa, I. Ribeiro; Mourão, C.; Récio, C.; Guimarães, F.; Antunes, I. M.; Ramos, J. Farinha; Barriga, F. J. A. S.; Palmer, M. R.; Milton, J. A.

2014-04-01

Tourmalinization associated with peraluminous granitic intrusions in metapelitic host-rocks has been widely recorded in the Iberian Peninsula, given the importance of tourmaline as a tracer of granite magma evolution and potential indicator of Sn-W mineralizations. In the Penamacor-Monsanto granite pluton (Central Eastern Portugal, Central Iberian Zone), tourmaline occurs: (1) as accessory phase in two-mica granitic rocks, muscovite-granites and aplites, (2) in quartz (±mica)-tourmaline rocks (tourmalinites) in several exocontact locations, and (3) as a rare detrital phase in contact zone hornfels and metapelitic host-rocks. Electron microprobe and stable isotope (δ18O, δD, δ11B) data provide clear distinctions between tourmaline populations from these different settings: (a) schorl-oxyschorl tourmalines from granitic rocks have variable foititic component (X□ = 17-57 %) and Mg/(Mg + Fe) ratios (0.19-0.50 in two-mica granitic rocks, and 0.05-0.19 in the more differentiated muscovite-granite and aplites); granitic tourmalines have constant δ18O values (12.1 ± 0.1 ‰), with wider-ranging δD (-78.2 ± 4.7 ‰) and δ11B (-10.7 to -9.0 ‰) values; (b) vein/breccia oxyschorl [Mg/(Mg + Fe) = 0.31-0.44] results from late, B- and Fe-enriched magma-derived fluids and is characterized by δ18O = 12.4 ‰, δD = -29.5 ‰, and δ11B = -9.3 ‰, while replacement tourmalines have more dravitic compositions [Mg/(Mg + Fe) = 0.26-0.64], close to that of detrital tourmaline in the surrounding metapelitic rocks, and yield relatively constant δ18O values (13.1-13.3 ‰), though wider-ranging δD (-58.5 to -36.5 ‰) and δ11B (-10.2 to -8.8 ‰) values; and (c) detrital tourmaline in contact rocks and regional host metasediments is mainly dravite [Mg/(Mg + Fe) = 0.35-0.78] and oxydravite [Mg/(Mg + Fe) = 0.51-0.58], respectively. Boron contents of the granitic rocks are low (<650 ppm) compared to the minimum B contents normally required for tourmaline saturation in granitic melts, implying loss of B and other volatiles to the surrounding host-rocks during the late-magmatic stages. This process was responsible for tourmalinization at the exocontact of the Penamacor-Monsanto pluton, either as direct tourmaline precipitation in cavities and fractures crossing the pluton margin (vein/breccia tourmalinites), or as replacement of mafic minerals (chlorite or biotite) in the host-rocks (replacement tourmalinites) along the exocontact of the granite. Thermometry based on 18O equilibrium fractionation between tourmaline and fluid indicates that a late, B-enriched magmatic aqueous fluid (av. δ18O ~12.1 ‰, at ~600 °C) precipitated the vein/breccia tourmaline (δ18O ~12.4 ‰) at ~500-550 °C, and later interacted with the cooler surrounding host-rocks to produce tourmaline at lower temperatures (400-450 °C), and an average δ18O ~13.2 ‰, closer to the values for the host-rock. Although B-metasomatism associated with some granitic plutons in the Iberian Peninsula seems to be relatively confined in space, extending integrated studies such as this to a larger number of granitic plutons may afford us a better understanding of Variscan magmatism and related mineralizations.

Host parasite communications-Messages from helminths for the immune system: Parasite communication and cell-cell interactions.

PubMed

Coakley, Gillian; Buck, Amy H; Maizels, Rick M

2016-07-01

Helminths are metazoan organisms many of which have evolved parasitic life styles dependent on sophisticated manipulation of the host environment. Most notably, they down-regulate host immune responses to ensure their own survival, by exporting a range of immuno-modulatory mediators that interact with host cells and tissues. While a number of secreted immunoregulatory parasite proteins have been defined, new work also points to the release of extracellular vesicles, or exosomes, that interact with and manipulate host gene expression. These recent results are discussed in the overall context of how helminths communicate effectively with the host organism. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Endogenous Retroviruses: With Us and Against Us

NASA Astrophysics Data System (ADS)

Meyer, Thomas J.; Rosenkrantz, Jimi L.; Carbone, Lucia; Chavez, Shawn L.

2017-04-01

Mammalian genomes are scattered with thousands of copies of endogenous retroviruses (ERVs), mobile genetic elements that are relics of ancient retroviral infections. After inserting copies into the germ line of a host, most ERVs accumulate mutations that prevent the normal assembly of infectious viral particles, becoming trapped in host genomes and unable to leave to infect other cells. While most copies of ERVs are inactive, some are transcribed and encode the proteins needed to generate new insertions at novel loci. In some cases, old copies are removed via recombination and other mechanisms. This creates a shifting landscape of ERV copies within host genomes. New insertions can disrupt normal expression of nearby genes via directly inserting into key regulatory elements or by containing regulatory motifs within their sequences. Further, the transcriptional silencing of ERVs via epigenetic modification may result in changes to the epigenetic regulation of adjacent genes. In these ways, ERVs can be potent sources of regulatory disruption as well as genetic innovation. Here, we provide a brief review of the association between ERVs and gene expression, especially as observed in pre-implantation development and placentation. Moreover, we will describe the roles ERVs may play in somatic tissues, mostly in the context of human disease, including cancer, neurodegenerative disorders, and schizophrenia. Lastly, we discuss the recent discovery that some ERVs may have been pressed into the service of their host genomes to aid in the innate immune response to exogenous viral infections.

Differentiation of presumptive primordial germ cell (pPGC)-like cells in explants into PGCs in experimental tadpoles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikenishi, K.; Okuda, T.; Nakazato, S.

1984-05-01

A single blastomere containing the ''germ plasm'' of 32-cell stage Xenopus embryos was cultured with (/sup 3/H)thymidine until the control embryos developed to the neurula stage. The explants, showing a spherical mass in which the nuclei of all cells were labeled, were implanted into the prospective place of presumptive primordial germ cells (pPGCs) in the endodermal cell mass of unlabeled host embryos of the neurula stage. Labeled PGCs as well as unlabeled, host PGCs were found in the genital ridges of experimental tadpoles. This indicates that the precursor of germ cells, corresponding to pPGCs in normal embryos of the neurulamore » stage, in the explants migrated to genital ridges just at the right moment to become PGCs, and suggests that the developmental process progressed normally, even in the explants, as far as the differentiation of pPGCs is concerned.« less

Does scavenging extend the host range of entomopathogenic nematodes (Nematoda: Steinernematidae)?

PubMed

Půza, Vladimír; Mrácek, Zdenĕk

2010-05-01

Living and freeze-killed natural and laboratory hosts, with different susceptibility to entomopathogenic nematodes, were exposed to the larvae of Steinernema affine and Steinernema kraussei in two different experimental arenas (Eppendorf tubes, Petri dishes), and the success of the colonisation and eventual progeny production were observed. Both nematodes were able to colonise both living and dead larvae of Galleria mellonella (Lepidoptera) and adult Blatella germanica (Blattodea) even though the progeny production in dead hosts was lower on average. Living carabid beetles, Poecilus cupreus, and elaterid larvae (Coleoptera) were resistant to the infection, however, both nematodes were able to colonise and multiply in several dead P. cupreus and in a majority of dead elaterid larvae. By scavenging, EPNs can utilise cadavers of insects that are naturally resistant to EPN infection, and so broaden their host range. (c) 2010 Elsevier Inc. All rights reserved.

Fluid involvement in normal faulting

NASA Astrophysics Data System (ADS)

Sibson, Richard H.

2000-04-01

Evidence of fluid interaction with normal faults comes from their varied role as flow barriers or conduits in hydrocarbon basins and as hosting structures for hydrothermal mineralisation, and from fault-rock assemblages in exhumed footwalls of steep active normal faults and metamorphic core complexes. These last suggest involvement of predominantly aqueous fluids over a broad depth range, with implications for fault shear resistance and the mechanics of normal fault reactivation. A general downwards progression in fault rock assemblages (high-level breccia-gouge (often clay-rich) → cataclasites → phyllonites → mylonite → mylonitic gneiss with the onset of greenschist phyllonites occurring near the base of the seismogenic crust) is inferred for normal fault zones developed in quartzo-feldspathic continental crust. Fluid inclusion studies in hydrothermal veining from some footwall assemblages suggest a transition from hydrostatic to suprahydrostatic fluid pressures over the depth range 3-5 km, with some evidence for near-lithostatic to hydrostatic pressure cycling towards the base of the seismogenic zone in the phyllonitic assemblages. Development of fault-fracture meshes through mixed-mode brittle failure in rock-masses with strong competence layering is promoted by low effective stress in the absence of thoroughgoing cohesionless faults that are favourably oriented for reactivation. Meshes may develop around normal faults in the near-surface under hydrostatic fluid pressures to depths determined by rock tensile strength, and at greater depths in overpressured portions of normal fault zones and at stress heterogeneities, especially dilational jogs. Overpressures localised within developing normal fault zones also determine the extent to which they may reutilise existing discontinuities (for example, low-angle thrust faults). Brittle failure mode plots demonstrate that reactivation of existing low-angle faults under vertical σ1 trajectories is only likely if fluid overpressures are localised within the fault zone and the surrounding rock retains significant tensile strength. Migrating pore fluids interact both statically and dynamically with normal faults. Static effects include consideration of the relative permeability of the faults with respect to the country rock, and juxtaposition effects which determine whether a fault is transmissive to flow or acts as an impermeable barrier. Strong directional permeability is expected in the subhorizontal σ2 direction parallel to intersections between minor faults, extension fractures, and stylolites. Three dynamic mechanisms tied to the seismic stress cycle may contribute to fluid redistribution: (i) cycling of mean stress coupled to shear stress, sometimes leading to postfailure expulsion of fluid from vertical fractures; (ii) suction pump action at dilational fault jogs; and, (iii) fault-valve action when a normal fault transects a seal capping either uniformly overpressured crust or overpressures localised to the immediate vicinity of the fault zone at depth. The combination of σ2 directional permeability with fluid redistribution from mean stress cycling may lead to hydraulic communication along strike, contributing to the protracted earthquake sequences that characterise normal fault systems.

Compositional and isotopic heterogeneities in the Neo-Tethyan upper mantle recorded by coexisting Al-rich and Cr-rich chromitites in the Purang peridotite massif, SW Tibet (China)

NASA Astrophysics Data System (ADS)

Xiong, Fahui; Yang, Jingsui; Xu, Xiangzhen; Kapsiotis, Argyrios; Hao, Xiaolin; Liu, Zhao

2018-06-01

The Purang harzburgite massif in SW Tibet (China) hosts abundant chrome ore deposits. Ores consist of 20 to >95% modal chromian spinel (Cr-spinel) with mylonitic fabric in imbricate shaped pods. The composition of Cr-spinel in these ores ranges from Al-rich [Cr#Sp or Cr/(Cr + Al) × 100 = 47.60-57.56] to Cr-rich (Cr#Sp: 62.55-79.57). Bulk platinum-group element (PGE) contents of chromitites are also highly variable ranging from 17.5 ppb to ∼2.5 ppm. Both metallurgical and refractory chromitites show a general enrichment in the IPGE (Os, Ir and Ru) with respect to the PPGE (Rh, Pt and Pd), resulting mostly in right-sloping primitive mantle (PM)-normalized PGE profiles. The platinum-group mineral (PGM) assemblages of both chromitite types are dominated by heterogeneously distributed, euhedral Os-bearing laurite inclusions in Cr-spinel. The Purang chromitites have quite inhomogeneous 187Os/188Os ratios (0.12289-0.13194) that are within the range of those reported for mantle-hosted chromitites from other peridotite massifs. Geochemical calculations demonstrate that the parental melts of high-Cr chromitites were boninitic, whereas those of high-Al chromitites had an arc-type tholeiitic affinity. Chromite crystallization was most likely stimulated by changes in magma compositions due to melt-peridotite interaction, leading to the establishment of a heterogeneous physicochemical environment during the early crystallization of the PGM. The highly variable PGE contents, inhomogeneous Os-isotopic compositions and varying Cr#Sp ratios of these chromitites imply a polygenetic origin for them from spatially distinct melt inputs. The generally low γOs values (<1) of chromitites indicate that their parental melts originated within different sections of a heterogeneously depleted mantle source region. These melts were most likely produced in the mantle wedge above a downgoing lithospheric slab.

Characterization of isolates of meloidogyne from rice-wheat production fields in Nepal.

PubMed

Pokharel, Ramesh R; Abawi, George S; Zhang, Ning; Duxbury, John M; Smart, Christine D

2007-09-01

Thirty-three isolates of root-knot nematode were recovered from soil samples from rice-wheat fields in Nepal and maintained on rice cv. BR 11. The isolates were characterized using morphology, host range and DNA sequence analyses in order to ascertain their identity. Results indicated phenotypic similarity (juvenile measurements, perennial pattern, host range and gall shape) of the Nepalese isolates with Meloidogyne graminicola, with minor variations. The rice varieties LA 110 and Labelle were susceptible to all of the Nepalese isolates, but differences in the aggressiveness of the isolates were observed. Phylogenetic analyses based on the sequences of partial internal transcribed spacer (ITS) of the rRNA genes indicated that all Nepalese isolates formed a distinct clade with known isolates of M. graminicola with high bootstrap support. Furthermore, two groups were identified within the M. graminicola clade. No correlation between ITS haplotype and aggressiveness or host range was found among the tested isolates.

Bacteria influence mountain pine beetle brood development through interactions with symbiotic and antagonistic fungi: implications for climate-driven host range expansion.

PubMed

Therrien, Janet; Mason, Charles J; Cale, Jonathan A; Adams, Aaron; Aukema, Brian H; Currie, Cameron R; Raffa, Kenneth F; Erbilgin, Nadir

2015-10-01

Bark beetles are associated with diverse communities of symbionts. Although fungi have received significant attention, we know little about how bacteria, and in particular their interactions with fungi, affect bark beetle reproduction. We tested how interactions between four bacterial associates, two symbiotic fungi, and two opportunistic fungi affect performance of mountain pine beetles (Dendroctonus ponderosae) in host tissue. We compared beetle performance in phloem of its historical host, lodgepole pine (Pinus contorta), and its novel host recently accessed through warming climate, jack pine (Pinus banksiana). Overall, beetles produced more larvae, and established longer ovipositional and larval galleries in host tissue predominantly colonized by the symbiotic fungi, Grosmannia clavigera, or Ophiostoma montium than by the opportunistic colonizer Aspergillus and to a lesser extent, Trichoderma. This occurred in both historical and naïve hosts. Impacts of bacteria on beetle reproduction depended on particular fungus-bacterium combinations and host species. Some bacteria, e.g., Pseudomonas sp. D4-22 and Hy4T4 in P. contorta and Pseudomonas sp. Hy4T4 and Stenotrophomonas in P. banksiana, reduced antagonistic effects by Aspergillus and Trichoderma resulting in more larvae and longer ovipositional and larval galleries. These effects were not selective, as bacteria also reduced beneficial effects by symbionts in both host species. Interestingly, Bacillus enhanced antagonistic effects by Aspergillus in both hosts. These results demonstrate that bacteria influence brood development of bark beetles in host tissue. They also suggest that climate-driven range expansion of D. ponderosae through the boreal forest will not be significantly constrained by requirements of, or interactions among, its microbial associates.

Role of Interleukin 10 Transcriptional Regulation in Inflammation and Autoimmune Disease

PubMed Central

Iyer, Shankar Subramanian; Cheng, Genhong

2012-01-01

Interleukin 10 (IL-10) is a cytokine with potent anti-inflammatory properties that plays a central role in limiting host immune response to pathogens, thereby preventing damage to the host and maintaining normal tissue homeostasis. Dysregulation of IL-10 is associated with enhanced immunopathology in response to infection as well as increased risk for development of many autoimmune diseases. Thus a fundamental understanding of IL-10 gene expression is critical for our comprehension of disease progression and resolution of host inflammatory response. In this review, we discuss modes of regulation of IL-10 gene expression in immune effector cell types, including signal transduction, epigenetics, promoter architecture, and post-transcriptional regulation, and how aberrant regulation contributes to immunopathology and disease progression. PMID:22428854

How pathogens use linear motifs to perturb host cell networks.

PubMed

Via, Allegra; Uyar, Bora; Brun, Christine; Zanzoni, Andreas

2015-01-01

Molecular mimicry is one of the powerful stratagems that pathogens employ to colonise their hosts and take advantage of host cell functions to guarantee their replication and dissemination. In particular, several viruses have evolved the ability to interact with host cell components through protein short linear motifs (SLiMs) that mimic host SLiMs, thus facilitating their internalisation and the manipulation of a wide range of cellular networks. Here we present convincing evidence from the literature that motif mimicry also represents an effective, widespread hijacking strategy in prokaryotic and eukaryotic parasites. Further insights into host motif mimicry would be of great help in the elucidation of the molecular mechanisms behind host cell invasion and the development of anti-infective therapeutic strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

A virus or more in (nearly) every cell: ubiquitous networks of virus-host interactions in extreme environments.

PubMed

Munson-McGee, Jacob H; Peng, Shengyun; Dewerff, Samantha; Stepanauskas, Ramunas; Whitaker, Rachel J; Weitz, Joshua S; Young, Mark J

2018-06-01

The application of viral and cellular metagenomics to natural environments has expanded our understanding of the structure, functioning, and diversity of microbial and viral communities. The high diversity of many communities, e.g., soils, surface ocean waters, and animal-associated microbiomes, make it difficult to establish virus-host associations at the single cell (rather than population) level, assign cellular hosts, or determine the extent of viral host range from metagenomics studies alone. Here, we combine single-cell sequencing with environmental metagenomics to characterize the structure of virus-host associations in a Yellowstone National Park (YNP) hot spring microbial community. Leveraging the relatively low diversity of the YNP environment, we are able to overlay evidence at the single-cell level with contextualized viral and cellular community structure. Combining evidence from hexanucelotide analysis, single cell read mapping, network-based analytics, and CRISPR-based inference, we conservatively estimate that >60% of cells contain at least one virus type and a majority of these cells contain two or more virus types. Of the detected virus types, nearly 50% were found in more than 2 cellular clades, indicative of a broad host range. The new lens provided by the combination of metaviromics and single-cell genomics reveals a network of virus-host interactions in extreme environments, provides evidence that extensive virus-host associations are common, and further expands the unseen impact of viruses on cellular life.

Implications of a temperature increase for host plant range: predictions for a butterfly

PubMed Central

Audusseau, Hélène; Nylin, Sören; Janz, Niklas

2013-01-01

Although changes in phenology and species associations are relatively well-documented responses to global warming, the potential interactions between these phenomena are less well understood. In this study, we investigate the interactions between temperature, phenology (in terms of seasonal timing of larval growth) and host plant use in the polyphagous butterfly Polygonia c-album. We found that the hierarchy of larval performance on three natural host plants was not modified by a temperature increase as such. However, larval performance on each host plant and temperature treatment was affected by rearing season. Even though larvae performed better at the higher temperature regardless of the time of the rearing, relative differences between host plants changed with the season. For larvae reared late in the season, performance was always better on the herbaceous plant than on the woody plants. In this species, it is likely that a prolonged warming will lead to a shift from univoltinism to bivoltinism. The demonstrated interaction between host plant suitability and season means that such a shift is likely to lead to a shift in selective regime, favoring specialization on the herbaceous host. Based on our result, we suggest that host range evolution in response to temperature increase would in this species be highly contingent on whether the population undergoes a predicted shift from one to two generations. We discuss the effect of global warming on species associations and the outcome of asynchrony in rates of phenological change. PMID:24101991

Long-range correlations improve understanding of the influence of network structure on contact dynamics.

PubMed

Peyrard, N; Dieckmann, U; Franc, A

2008-05-01

Models of infectious diseases are characterized by a phase transition between extinction and persistence. A challenge in contemporary epidemiology is to understand how the geometry of a host's interaction network influences disease dynamics close to the critical point of such a transition. Here we address this challenge with the help of moment closures. Traditional moment closures, however, do not provide satisfactory predictions close to such critical points. We therefore introduce a new method for incorporating longer-range correlations into existing closures. Our method is technically simple, remains computationally tractable and significantly improves the approximation's performance. Our extended closures thus provide an innovative tool for quantifying the influence of interaction networks on spatially or socially structured disease dynamics. In particular, we examine the effects of a network's clustering coefficient, as well as of new geometrical measures, such as a network's square clustering coefficients. We compare the relative performance of different closures from the literature, with or without our long-range extension. In this way, we demonstrate that the normalized version of the Bethe approximation-extended to incorporate long-range correlations according to our method-is an especially good candidate for studying influences of network structure. Our numerical results highlight the importance of the clustering coefficient and the square clustering coefficient for predicting disease dynamics at low and intermediate values of transmission rate, and demonstrate the significance of path redundancy for disease persistence.

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

PubMed

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

2014-11-01

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.

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

PubMed Central

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

Functional genomics of a generalist parasitic plant: Laser microdissection of host-parasite interface reveals host-specific patterns of parasite gene expression

PubMed Central

2013-01-01

Background Orobanchaceae is the only plant family with members representing the full range of parasitic lifestyles plus a free-living lineage sister to all parasitic lineages, Lindenbergia. A generalist member of this family, and an important parasitic plant model, Triphysaria versicolor regularly feeds upon a wide range of host plants. Here, we compare de novo assembled transcriptomes generated from laser micro-dissected tissues at the host-parasite interface to uncover details of the largely uncharacterized interaction between parasitic plants and their hosts. Results The interaction of Triphysaria with the distantly related hosts Zea mays and Medicago truncatula reveals dramatic host-specific gene expression patterns. Relative to above ground tissues, gene families are disproportionally represented at the interface including enrichment for transcription factors and genes of unknown function. Quantitative Real-Time PCR of a T. versicolor β-expansin shows strong differential (120x) upregulation in response to the monocot host Z. mays; a result that is concordant with our read count estimates. Pathogenesis-related proteins, other cell wall modifying enzymes, and orthologs of genes with unknown function (annotated as such in sequenced plant genomes) are among the parasite genes highly expressed by T. versicolor at the parasite-host interface. Conclusions Laser capture microdissection makes it possible to sample the small region of cells at the epicenter of parasite host interactions. The results of our analysis suggest that T. versicolor’s generalist strategy involves a reliance on overlapping but distinct gene sets, depending upon the host plant it is parasitizing. The massive upregulation of a T. versicolor β-expansin is suggestive of a mechanism for parasite success on grass hosts. In this preliminary study of the interface transcriptomes, we have shown that T. versicolor, and the Orobanchaceae in general, provide excellent opportunities for the characterization of plant genes with unknown functions. PMID:23302495

Reproductive Biology and Functional Response of Dineulophus phtorimaeae, a Natural Enemy of the Tomato Moth, Tuta absoluta

PubMed Central

Savino, Vivina; Coviella, Carlos E.; Luna, María G.

2012-01-01

The tomato moth, Tuta absoluta (Lepidoptera: Gelechiidae), is a major pest in South America and is at present an important invasive species in the Mediterranean Basin. The larval stadium mines leaves, stems, and fruits, and chemical control is the most used control method in both its original range and the invaded distribution regions. Since current T. absoluta control strategies seem limited, biological control is a prominent tool to be applied abroad. The naturally occurring larval ectoparasitoid in Argentina and Chile Dineulophus phtorimaeae (Hymenoptera: Eulophidae) has been reported to have potential biocontrol efficiency. In this study, the ovigeny strategy of D. phtorimaeae was analyzed throughout the adult female lifetime, and the functional response of females offered a range of 2–15 T. absoluta larvae was measured over a 48-hour period. Mean D. phtorimaeae egg load was 4.15 eggs, and egg production resulted in extremely synovigenic behavior. Meanwhile, a decreasing number of eggs, due to resorption, was found. Proportions of attacked (host-fed and/or parasitized) and only host-fed hosts by the ectoparasitoid were density independent for the tested host range, exhibiting a type I functional response to T. absoluta, with an attack rate of 0.20 host larvae. Meanings of this reproductive strategy in evolutionary time as well as the consequences for augmentative biological control programs are discussed. PMID:23464576

Host Range Testing of Diaphorencyrtus aligarhensis (Hymenoptera: Encyrtidae) for Use in Classical Biological Control of Diaphorina citri (Hemiptera: Liviidae) in California.

PubMed

Bistline-East, Allison; Pandey, Raju; Kececi, Mehmet; Hoddle, Mark S

2015-06-01

Host range tests for Diaphorencyrtus aligarhensis (Shafee, Alam, & Agarwal) (Hymenoptera: Encyrtidae), an endoparasitoid of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from Punjab Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species representing four psyllid families were exposed to mated D. aligarhensis females in four different treatment types: 1) short sequential no-choice treatments, 2) prolonged sequential no-choice treatments, 3) prolonged no-choice static treatments, and 4) choice treatments. Selection of nontarget psyllid species was based on phylogenetic proximity to D. citri, likelihood of being encountered by D. aligarhensis in the prospective release areas in California, and psyllid species in biological control of invasive weeds. D. aligarhensis exhibited high host affinity to D. citri, and only parasitized one nontarget species, the pestiferous potato psyllid, Bactericera cockerelli (Sulc), at low levels (<14%). Based on the results of this study, we conclude that D. aligarhensis has a narrow host range and exhibits a high level of host specificity, as it shows a significant attack preference for the target pest, D. citri. Results presented here suggest D. aligarhensis poses minimal risk to nontarget psyllid species in California. © 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.

The use of enzymopathic human red cells in the study of malarial parasite glucose metabolism.

PubMed

Roth, E; Joulin, V; Miwa, S; Yoshida, A; Akatsuka, J; Cohen-Solal, M; Rosa, R

1988-05-01

The in vitro growth of Plasmodium falciparum malaria parasites was assayed in mutant red cells deficient in either diphosphoglycerate mutase (DPGM) or phosphoglycerate kinase (PGK). In addition, cDNA probes developed for human DNA sequences coding for these enzymes were used to examine the parasite genome by means of restriction endonuclease digestion and Southern blot analysis of parasite DNA. In both types of enzymopathic red cells, parasite growth was normal. In infected DPGM deficient red cells, no DPGM activity could be detected, and in normal red cells, DPGM activity declined slightly in a manner suggestive of parasite catabolism of host protein. However, in infected PGK deficient red cells, there was a 100-fold increase in PGK activity, and in normal red cells, a threefold increase in PGK activity was observed. Parasite PGK could be recovered from isolated parasites, and a marked increase in heat instability of parasite PGK as compared with the host cell enzyme was noted. Neither cDNA probe was found to cross-react with DNA sequences in the parasite genome. It is concluded that the parasite has no requirement for DPGM, and probably has no gene for this enzyme. On the other hand, the parasite does require PGK, (an adenosine triphosphate [ATP] generating enzyme) and synthesizes its own enzyme, which must have been encoded in the parasite genome. The parasite PGK gene most likely lacks sufficient homology to be detected by a human cDNA probe. Enzymopathic red cells are useful tools for elucidating the glycolytic enzymology of parasites and their co-evolution with their human hosts.

Boring in response to bark and phloem extracts from North American trees does not explain host acceptance behavior of Orthotomicus erosus (Coleoptera: Scolytidae)

Treesearch

Abigail J. Walter; Stephen A. Kells; Robert C. Venette; Steven J. Seybold

2010-01-01

When invasive herbivorous insects encounter novel plant species, they must determine whether the novel plants are hosts. The Mediterranean pine engraver, Orthotomicus erosus (Wollaston), an exotic bark beetle poised to expand its range in North America, accepts hosts after contacting the bark. To test the hypothesis that O. erosus...

Geologic Carbon Sequestration in a Lightly Explored Basin: the Puget-Willamette Lowland

NASA Astrophysics Data System (ADS)

Jackson, J. S.

2007-12-01

The Puget-Willamette Lowland is located between the Cascade Range and Olympic Mountains-Coast Range. Exploration for oil and gas there commenced in 1890. Over 700 wells subsequently drilled yield one commercial gas discovery. Eocene sediments deposited west of an ancestral Cascade Range include a coal-bearing sequence covering much of the Puget-Willamette Lowland. The terrestrial deposits pass into marine deposits to the west. Syn- depositional normal faulting and strike-slip faulting are evident in several sub-basins. In the southern Lowland, normal faults were modified by episodes of late Eocene and Miocene transpression, which resulted in mild inversion of older normal faults Preserved sediments indicate that local subsidence continued into Miocene- Pliocene time, and was followed in the northern Lowland by extensive Pleistocene glaciation. In the northern Lowland, Holocene faulting is recognized in outcrop and is interpreted on seismic data acquired in Puget Sound. Structures formed by early Miocene or earlier events may have trapped migrating hydrocarbons. Structures formed or modified by Holocene faulting very probably post-date hydrocarbon generation and migration. The region appears to host potential geologic sequestration targets, including coals, sandstones, and vesicular basalt flows. The size and location of potential traps is poorly constrained by present data. Experience in better explored fore arc basins suggests 10 to 30 percent of the basin may be deformed into suitable trapping geometries. Modern seismic data is required to identify potential sequestration traps. More than one well will be required to confirm the presence and size of these traps. The present boom in oil and gas drilling has created a robust environment for seismic and drilling companies, who command unprecedented rates for their services. Only one seismic crew is presently active on the West Coast, and only a few exploration drilling rigs are available. If this environment persists, then sequestration efforts will compete directly with the hydrocarbon industry for these services, leading to higher service company prices as well as delayed schedules. Carbon sequestration policy thus entails financial incentives that allow geologic sequestration projects to compete for exploration services.

A Multi-Omic View of Host-Pathogen-Commensal Interplay in Salmonella-Mediated Intestinal Infection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaiser, Brooke LD; Li, Jie; Sanford, James A.

The potential for commensal microorganisms indigenous to a host (the ‘microbiome’ or ‘microbiota’) to alter infection outcome by influencing host-pathogen interplay is largely unknown. We used a multi-omics “systems” approach, incorporating proteomics, metabolomics, glycomics, and metagenomics, to explore the molecular interplay between the murine host, the pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), and commensal gut microorganisms during intestinal infection with S. Typhimurium. We find proteomic evidence that S. Typhimurium thrives within the infected 129/SvJ mouse gut without antibiotic pre-treatment, inducing inflammation and disrupting the intestinal microbiome (e.g., suppressing Bacteroidetes and Firmicutes while promoting growth of Salmonella and Enterococcus). Alterationmore » of the host microbiome population structure was highly correlated with gut environmental changes, including the accumulation of metabolites normally consumed by commensal microbiota. Finally, the less characterized phase of S. Typhimurium’s lifecycle was investigated, and both proteomic and glycomic evidence suggests S. Typhimurium may take advantage of increased fucose moieties to metabolize fucose while growing in the gut. The application of multiple omics measurements to Salmonella-induced intestinal inflammation provides insights into complex molecular strategies employed during pathogenesis between host, pathogen, and the microbiome.« less

Host community heterogeneity and the expression of host specificity in avian haemosporidia in the Western Cape, South Africa.

PubMed

Jones, Sharon M; Cumming, Graeme S; Peters, Jeffrey L

2018-05-16

Similar patterns of parasite prevalence in animal communities may be driven by a range of different mechanisms. The influences of host heterogeneity and host-parasite interactions in host community assemblages are poorly understood. We sampled birds at 27 wetlands in South Africa to compare four hypotheses explaining how host community heterogeneity influences host specificity in avian haemosporidia communities: the host-neutral hypothesis, the super-spreader hypothesis, the host specialist hypothesis and the heterogeneity hypothesis. A total of 289 birds (29%) were infected with Plasmodium, Haemoproteus and/or Leucocytozoon lineages. Leucocytozoon was the most diverse and generalist parasite genus, and Plasmodium the most conservative. The host-neutral and host specialist hypotheses received the most support in explaining prevalence by lineage (Leucocytozoon) and genus (Plasmodium and Haemoproteus), respectively. We observed that haemosporidian prevalence was potentially amplified or reduced with variation in host and/or parasitic taxonomic levels of analysis. Our results show that Leucocytozoon host abundance and diversity was influential to parasite prevalence at varying taxonomic levels, particularly within heterogeneous host communities. Furthermore, we note that prevalent mechanisms of infection can potentially act as distinct roots for shaping communities of avian haemosporidia.

Carbonate concretions as a significant component of ancient marine carbon cycles: Insights from paired organic and inorganic carbon isotope analyses of a Cretaceous shale

NASA Astrophysics Data System (ADS)

Loyd, S. J.

2014-12-01

Carbonate concretions often occur within fine-grained, organic-rich sedimentary rocks. This association reflects the common production of diagenetic minerals through biologic cycling of organic matter. Chemical analysis of carbonate concretions provides the rare opportunity to explore ancient shallow diagenetic environments, which are inherently transient due to progressive burial but are an integral component of the marine carbon cycle. The late Cretaceous Holz Shale (~80 Ma) contains abundant calcite concretions that exhibit textural and geochemical characteristics indicative of relatively shallow formation (i.e., near the sediment-water interface). Sampled concretions contain between 5.4 and 9.8 wt.% total inorganic carbon (TIC), or ~45 and 82 wt.% CaCO3, compared to host shale values which average ~1.5 wt.% TIC. Organic carbon isotope compositions (δ13Corg) are relatively constant in host and concretion samples ranging from ­-26.3 to -24.0‰ (VPDB). Carbonate carbon isotope compositions (δ13Ccarb) range from -22.5 to -3.4‰, indicating a significant but not entirely organic source of carbon. Concretions of the lower Holz Shale exhibit considerably elevated δ13Ccarb values averaging -4.8‰, whereas upper Holz Shale concretions express an average δ13Ccarb value of -17.0‰. If the remaining carbonate for lower Holz Shale concretions is sourced from marine fluids and/or dissolved marine carbonate minerals (e.g., shells), a simple mass balance indicates that ~28% of concretion carbon was sourced from organic matter and ~72% from late Cretaceous marine inorganic carbon (with δ13C ~ +2.5‰). Upper Holz Shale calculations indicate a ~73% contribution from organic matter and a ~27% contribution from inorganic carbon. When normalized for carbonate, organic contents within the concretions are ~2-13 wt.% enriched compared to host contents. This potentially reflects the protective nature of cementation that acts to limit permeability and chemical destruction of organic material. These data imply that concretion growth in shallow sediments can act as a significant and long-term sink for both marine inorganic and organic carbon.

Transmating: conjugative transfer of a new broad host range expression vector to various Bacillus species using a single protocol.

PubMed

Heinze, Simon; Kornberger, Petra; Grätz, Christian; Schwarz, Wolfgang H; Zverlov, Vladimir V; Liebl, Wolfgang

2018-06-08

The genus Bacillus includes a great variety of species with potential applications in biotechnology. While species such as B. subtilis or B. licheniformis are well-known and used to provide various products at industrial scale, other Bacillus species are less characterized and are not yet used in commercial processes. One reason for this is the fact that genetic manipulation of new isolates is usually complicated with conventional techniques which have to be adapted to each new strain. Even in well-established strains, the available transformation protocols often suffer from low efficiencies. In this paper, we provide a new broad host range E. coli/Bacillus shuttle vector, named pBACOV (Bacillus conjugation vector), that can be efficiently transferred to various Bacillus species using a single protocol. A variant of pBACOV carrying the sfGFP gene was successfully transferred to eight different species from the genus Bacillus and to one Paenibacillus species using triparental conjugation ("transmating"). This was achieved using a single protocol and worked for nine out of eleven tested acceptor species. The transmating procedure was used to test expression of the heterologous reporter gene sfGFP under control of the P aprE -promoter from B. subtilis in several Bacillus species in parallel. Expression of sfGFP was found in eight out of nine transmates. For several of the tested species, this is the first report of a method for genetic modification and heterologous gene expression. The expression level, analyzed by measuring the relative sfGFP-fluorescence normalized to the cell density of the cultures, was highest in B. mojavensis. The new shuttle vector pBACOV can be transferred to many different Bacillus and Paenibacillus species using a simple and efficient transmating protocol. It is a versatile tool facilitating the application of recombinant DNA technology in new as well as established strains, or selection of an ideal host for heterologous gene expression from a multitude of strains. This paves the way for the genetic modification and biotechnological exploitation of the broad diversity of species of Bacillus and related genera as well as different strains from these species.

Microbial colonization is required for normal neurobehavioral development in zebrafish..

EPA Science Inventory

Host-associated microbiota are a dynamic system that shapes organismal development. There is growing evidence that microbiota modify the toxicokinetics and/or toxicodynamics of environmental chemicals. To delineate the neurobehavioral consequences of microbial colonization, we ex...

Microbial colonization is required for normal neurobehavioral development in zebrafish.

EPA Science Inventory

Host-associated microbiota are a dynamic system that shapes organismal development. There is growing evidence that microbiota modify the toxicokinetics and/or toxicodynamics of environmental chemicals. To delineate the neurobehavioral consequences of microbial colonization, we ex...

Influence of internal electric fields on bonding and properties of impurities in insulators: Mn2+ in LiBaF3 and normal perovskites

NASA Astrophysics Data System (ADS)

Trueba, A.; García-Lastra, J. M.; Barriuso, M. T.; Aramburu, J. A.; Moreno, M.

2008-08-01

Although in LiBaF3:Mn2+ the impurity replaces Li+ thus forming octahedral MnF64- units the experimental hyperfine and anisotropic superhyperfine constants and the energies of d-d optical transitions do not fit into the pattern observed for Mn2+ -doped normal perovskite lattices. Seeking to look into this relevant issue first-principles calculations in the framework of the density-functional theory have been carried out for MnF64- complexes embedded in both KMgF3 and LiBaF3 host lattices which display normal and inverted perovskite structures respectively. The present calculations lead to a value of the equilibrium Mn2+-F- distance, RI , which is the same for both host lattices within 0.015Å . Despite this fact and in agreement with experimental data the calculated values of both the anisotropic superhyperfine constant, Ap , and the cubic-field splitting parameter, 10Dq, for LiBaF3:Mn2+ are found to be higher than those for KMgF3:Mn2+ while Racah parameters are a bit higher for the latter case. All these results, and also the 3% reduction undergone by the hyperfine constant on passing from KMgF3:Mn2+ to LiBaF3:Mn2+ are shown to be connected with a parallel increase in the covalency. These surprising results, which cannot be ascribed to a different RI value, are shown to arise from the internal electric field, ER , due to all lattice ions lying outside the MnF64- complex. Although, according to symmetry, ER is null at Mn2+ site this is shown to be not true in the neighborhood of ligands for the LiBaF3 host lattice. The quite different shape of ER in normal and inverted perovskite lattices is shown to be already understood considering only the first two shells surrounding the MnF64- complex. The present results demonstrate that the traditional ligand field theory fails to understand the changes undergone by optical and magnetic parameters of a complex when a host lattice is replaced by another one which is not isomorphous. The relevance of present conclusions for understanding the color of Cr3+ -based gemstones is also underlined.

Amino Acid Control over Deoxyribonucleic Acid Synthesis in Escherichia coli Infected With T-Even Bacteriophage

PubMed Central

Donini, Pierluigi

1970-01-01

Starvation for a required amino acid of normal or RCstrEscherichia coli infected with T-even phages arrests further synthesis of phage deoxyribonucleic acid (DNA). This amino acid control over phage DNA synthesis does not occur in RCrelE. coli mutants. Heat inactivation of a temperature-sensitive aminoacyl-transfer ribonucleic acid (RNA) synthetase similarly causes an arrest of phage DNA synthesis in infected cells of RCstr phenotype but not in cells of RCrel phenotype. Inhibition of phage DNA synthesis in amino acid-starved RCstr host cells can be reversed by addition of chloramphenicol to the culture. Thus, the general features of amino acid control over T-even phage DNA synthesis are entirely analogous to those known for amino acid control over net RNA synthesis of uninfected bacteria. This analogy shows that the bacterial rel locus controls a wider range of macromolecular syntheses than had been previously thought. PMID:4914067

Development and cytotoxicity of Schiff base derivative as a fluorescence probe for the detection of L-Arginine

NASA Astrophysics Data System (ADS)

Shang, Xuefang; Li, Jie; Guo, Kerong; Ti, Tongyu; Wang, Tianyun; Zhang, Jinlian

2017-04-01

Inspired from biological counter parts, chemical modification of Schiff base derivatives with function groups may provide a highly efficient method to detect amino acids. Therefore, a fluorescent probe involving Schiff base and hydroxyl group has been designed and prepared, which showed high response and specificity for Arginine (Arg) among normal eighteen standard kinds of amino acids (Alanine, Valine, Leucine, Isoleucine, Methionine, Asparticacid, Glutamicacid, Arginine, Glycine, Serine, Threonine, Asparagine, Phenylalanine, Histidine, Tryptophan, Proline, Lysine, Glutamine, Tyrosine and Cysteine). Furthermore, theoretical investigation further illustrated the possible binding mode in the host-guest interaction and the roles of molecular frontier orbitals in molecular interplay. In addition, the synthesized fluorescent probe exhibited high binding ability for Arg and low cytotoxicity to MCF-7 cells over a concentration range of 0-200 μg mL-1 which can be also used as a biosensor for the Arg detection in vivo.

THE HIGH BACKGROUND RADIATION AREA IN RAMSAR IRAN: GEOLOGY, NORM, BIOLOGY, LNT, AND POSSIBLE REGULATORY FUN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karam, P. A.

2002-02-25

The city of Ramsar Iran hosts some of the highest natural radiation levels on earth, and over 2000 people are exposed to radiation doses ranging from 1 to 26 rem per year. Curiously, inhabitants of this region seem to have no greater incidence of cancer than those in neighboring areas of normal background radiation levels, and preliminary studies suggest their blood cells experience fewer induced chromosomal abnormalities when exposed to 150 rem ''challenge'' doses of radiation than do the blood cells of their neighbors. This paper will briefly describe the unique geology that gives Ramsar its extraordinarily high background radiationmore » levels. It will then summarize the studies performed to date and will conclude by suggesting ways to incorporate these findings (if they are borne out by further testing) into future radiation protection standards.« less

Chronically Implanted Pressure Sensors: Challenges and State of the Field

PubMed Central

Yu, Lawrence; Kim, Brian J.; Meng, Ellis

2014-01-01

Several conditions and diseases are linked to the elevation or depression of internal pressures from a healthy, normal range, motivating the need for chronic implantable pressure sensors. A simple implantable pressure transduction system consists of a pressure-sensing element with a method to transmit the data to an external unit. The biological environment presents a host of engineering issues that must be considered for long term monitoring. Therefore, the design of such systems must carefully consider interactions between the implanted system and the body, including biocompatibility, surgical placement, and patient comfort. Here we review research developments on implantable sensors for chronic pressure monitoring within the body, focusing on general design requirements for implantable pressure sensors as well as specifications for different medical applications. We also discuss recent efforts to address biocompatibility, efficient telemetry, and drift management, and explore emerging trends. PMID:25365461

Host range of the emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae) in North America: results of multiple-choice field experiments.

PubMed

Anulewicz, Andrea C; McCullough, Deborah G; Cappaert, David L; Poland, Therese M

2008-02-01

Emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae), an invasive phloem-feeding pest, was identified as the cause of widespread ash (Fraxinus) mortality in southeast Michigan and Windsor, Ontario, Canada, in 2002. A. planipennis reportedly colonizes other genera in its native range in Asia, including Ulmus L., Juglans L., and Pterocarya Kunth. Attacks on nonash species have not been observed in North America to date, but there is concern that other genera could be colonized. From 2003 to 2005, we assessed adult A. planipennis landing rates, oviposition, and larval development on North American ash species and congeners of its reported hosts in Asia in multiple-choice field studies conducted at several southeast Michigan sites. Nonash species evaluated included American elm (U. americana L.), hackberry (Celtis occidentalis L.), black walnut (J. nigra L.), shagbark hickory [Carya ovata (Mill.) K.Koch], and Japanese tree lilac (Syringa reticulata Bl.). In studies with freshly cut logs, adult beetles occasionally landed on nonash logs but generally laid fewer eggs than on ash logs. Larvae fed and developed normally on ash logs, which were often heavily infested. No larvae were able to survive, grow, or develop on any nonash logs, although failed first-instar galleries occurred on some walnut logs. High densities of larvae developed on live green ash and white ash nursery trees, but there was no evidence of larval survival or development on Japanese tree lilac and black walnut trees in the same plantation. We felled, debarked, and intensively examined >28 m2 of phloem area on nine American elm trees growing in contact with or adjacent to heavily infested ash trees. We found no sign of A. planipennis feeding on any elm.

Host Plant Record for the Fruit Flies, Anastrepha fumipennis and A. nascimentoi (Diptera, Tephritidae)

PubMed Central

Uramoto, Keiko; Martins, David S.; Lima, Rita C. A.; Zucchi, Roberto A.

2008-01-01

The first host plant record for Anastrepha fumipennis Lima (Diptera: Tephritidae) in Geissospermum laeve (Vell.) Baill (Apocynaceae) and for A. nascimentoi Zucchi found in Cathedra bahiensis Sleumer (Olacaceae) was determined in a host plant survey of fruit flies undertaken at the “Reserva Natural da Companhia Vale do Rio Doce”. This reserve is located in an Atlantic Rain Forest remnant area, in Linhares county, state of Espírito Santo, Brazil. The phylogenetic relationships of Anastrepha species and their hosts are discussed. The occurrence of these fruit fly species in relation to the distribution range of their host plants is also discussed. PMID:20302458

The Thermodynamics of Anion Complexation to Nonpolar Pockets.

PubMed

Sullivan, Matthew R; Yao, Wei; Tang, Du; Ashbaugh, Henry S; Gibb, Bruce C

2018-02-08

The interactions between nonpolar surfaces and polarizable anions lie in a gray area between the hydrophobic and Hofmeister effects. To assess the affinity of these interactions, NMR and ITC were used to probe the thermodynamics of eight anions binding to four different hosts whose pockets each consist primarily of hydrocarbon. Two classes of host were examined: cavitands and cyclodextrins. For all hosts, anion affinity was found to follow the Hofmeister series, with associations ranging from 1.6-5.7 kcal mol -1 . Despite the fact that cavitand hosts 1 and 2 possess intrinsic negative electrostatic fields, it was determined that these more enveloping hosts generally bound anions more strongly. The observation that the four hosts each possess specific anion affinities that cannot be readily explained by their structures, points to the importance of counter cations and the solvation of the "empty" hosts, free guests, and host-guest complexes, in defining the affinity.

Rapidly expanding genetic diversity and host range of the Circoviridae viral family and other Rep encoding small circular ssDNA genomes.

PubMed

Delwart, Eric; Li, Linlin

2012-03-01

The genomes of numerous circoviruses and distantly related circular ssDNA viruses encoding a rolling circle replication initiator protein (Rep) have been characterized from the tissues of mammals, fish, insects, plants (geminivirus and nanovirus), in human and animal feces, in an algae cell, and in diverse environmental samples. We review the genome organization, phylogenetic relationships and initial prevalence studies of cycloviruses, a proposed new genus in the Circoviridae family. Viral fossil rep sequences were also recently identified integrated on the chromosomes of mammals, frogs, lancelets, crustaceans, mites, gastropods, roundworms, placozoans, hydrozoans, protozoans, land plants, fungi, algae, and phytoplasma bacterias and their plasmids, reflecting the very wide past host range of rep bearing viruses. An ancient origin for viruses with Rep-encoding small circular ssDNA genomes, predating the diversification of eukaryotes, is discussed. The cellular hosts and pathogenicity of many recently described rep-containing circular ssDNA genomes remain to be determined. Future studies of the virome of single cell and multi-cellular eukaryotes are likely to further extend the known diversity and host-range of small rep-containing circular ssDNA viral genomes. Copyright © 2011 Elsevier B.V. All rights reserved.

Transplantation of Adipose Derived Stromal Cells into the Developing Mouse Eye

PubMed Central

Yu, Song-Hee; Jang, Yu-Jin; Lee, Eun-Shil; Hwang, Dong-Youn; Jeon, Chang-Jin

2010-01-01

Adipose derived stromal cells (ADSCs) were transplanted into a developing mouse eye to investigate the influence of a developing host micro environment on integration and differentiation. Green fluorescent protein-expressing ADSCs were transplanted by intraocular injections. The age of the mouse was in the range of 1 to 10 days postnatal (PN). Survival dates ranged from 7 to 28 post transplantation (DPT), at which time immunohistochemistry was performed. The transplanted ADSCs displayed some morphological differentiations in the host eye. Some cells expressed microtubule associated protein 2 (marker for mature neuron), or glial fibrillary acid protein (marker for glial cell). In addition, some cells integrated into the ganglion cell layer. The integration and differentiation of the transplanted ADSCs in the 5 and 10 PN 7 DPT were better than in the host eye the other age ranges. This study was aimed at demonstrating how the age of host micro environment would influence the differentiation and integration of the transplanted ADSCs. However, it was found that the integration and differentiation into the developing retina were very limited when compared with other stem cells, such as murine brain progenitor cell. PMID:21245978

Detection of antibodies to Trypanosoma cruzi in the South American opossum (Didelphis marsupialis).

PubMed

Luckins, A G; Miles, M A

1982-01-01

Stocks of Trypanosoma cruzi belonging to two different zymodemes, one usually associated with silvatic reservoir hosts and the other not normally found in wild reservoir hosts, were used as sources of diagnostic antigens in enzyme-linked immunosorbent assays for the detection of antibodies to T. cruzi in Didelphis marsupialis. Both antigen preparations reacted with antibodies in sera from animals found to be infected by conventional parasitological techniques and also in sera from a proportion of the remaining animals in which it was not possible to detect trypanosomes.

Potential Pathogenicity and Host Range of Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolates from Healthy Poultry ▿

PubMed Central

Bortolaia, Valeria; Larsen, Jesper; Damborg, Peter; Guardabassi, Luca

2011-01-01

Thirty of 33 epidemiologically unrelated extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates from healthy poultry lacked the virulence genes commonly associated with human-pathogenic strains. The main zoonotic risk is associated with the broad host range of avian E. coli belonging to sequence type complex 10 and of IncN and IncI1 plasmids carrying blaCTX-M or blaSHV. PMID:21705531

Genomic characterization of Ralstonia solanacearum phage phiRSB1, a T7-like wide-host-range phage.

PubMed

Kawasaki, Takeru; Shimizu, Mio; Satsuma, Hideki; Fujiwara, Akiko; Fujie, Makoto; Usami, Shoji; Yamada, Takashi

2009-01-01

PhiRSB1 is a wide-host-range, T7-like bacteriophage that infects and efficiently lyses the phytopathogenic bacterium Ralstonia solanacearum. The phiRSB1 genome comprises 43,079 bp of double-stranded DNA (61.7% G+C) with 325-bp terminal repeats and contains 47 open reading frames. Strong activity of tandem early promoters and wide specificity of phage promoters of phiRSB1 were demonstrated.

Divergent Nod-Containing Bradyrhizobium sp. DOA9 with a Megaplasmid and its Host Range

PubMed Central

Teamtisong, Kamonluck; Songwattana, Pongpan; Noisangiam, Rujirek; Piromyou, Pongdet; Boonkerd, Nantakorn; Tittabutr, Panlada; Minamisawa, Kiwamu; Nantagij, Achara; Okazaki, Shin; Abe, Mikiko; Uchiumi, Toshiki; Teaumroong, Neung

2014-01-01

Bradyrhizobium sp. DOA9, a non-photosynthetic bacterial strain originally isolated from the root nodules of the legume Aeschynomene americana, is a divergent nod-containing strain. It exhibits a broad host range, being able to colonize and efficiently nodulate the roots of most plants from the Dalbergioid, Millettioid, and Robinioid tribes (7 species of Papilionoideae). In all cases, nodulation was determinate. The morphology and size of DOA9 bacteroids isolated from the nodules of various species of Papilionoideae were indistinguishable from the free-living form. However, they were spherical in Arachis hypogaea nodules. GusA-tagged DOA9 also colonized rice roots as endophytes. Since broad-host-range legume symbionts often carry multiple replicons in their genome, we analyzed the replicons for symbiosis genes by electrophoresis. DOA9 carried two replicons, a chromosome (cDOA9) and single megaplasmid (pDOA9) larger than 352 kb. The genes for nodulation (nodA, B, C) and nitrogen fixation (nifH) were localized on the megaplasmid. Southern blot hybridization revealed two copies of nodA on the megaplasmid, single copies of nodB and C on the megaplasmid, and one copy each of nifH on the chromosome and megaplasmid. These results suggested that Bradyrhizobium sp. DOA9 may have the unusual combination of a broad host range, bacteroid differentiation, and symbiosis-mediating replicons. PMID:25283477

The Evolution of Clutch Size in Hosts of Avian Brood Parasites.

PubMed

Medina, Iliana; Langmore, Naomi E; Lanfear, Robert; Kokko, Hanna

2017-11-01

Coevolution with avian brood parasites shapes a range of traits in their hosts, including morphology, behavior, and breeding systems. Here we explore whether brood parasitism is also associated with the evolution of host clutch size. Several studies have proposed that hosts of highly virulent parasites could decrease the costs of parasitism by evolving a smaller clutch size, because hosts with smaller clutches will lose fewer progeny when their clutch is parasitized. We describe a model of the evolution of clutch size, which challenges this logic and shows instead that an increase in clutch size (or no change) should evolve in hosts. We test this prediction using a broad-scale comparative analysis to ask whether there are differences in clutch size within hosts and between hosts and nonhosts. Consistent with our model, this analysis revealed that host species do not have smaller clutches and that hosts that incur larger costs from raising a parasite lay larger clutches. We suggest that brood parasitism might be an influential factor in clutch-size evolution and could potentially select for the evolution of larger clutches in host species.

Seasonal Alterations in Host Range and Fidelity in the Polyphagous Mirid Bug, Apolygus lucorum (Heteroptera: Miridae)

PubMed Central

Pan, Hongsheng; Liu, Bing; Lu, Yanhui; Wyckhuys, Kris A. G.

2015-01-01

In herbivorous insects, host plant switching is commonly observed and plays an important role in their annual life cycle. However, much remains to be learned about seasonal host switching of various pestiferous arthropods under natural conditions. From 2006 until 2012, we assessed Apolygus lucorum (Meyer-Dür) host plant use in successive spring, summer and winter seasons at one single location (Langfang, China). Data were used to quantify changes in host plant breadth and host fidelity between seasons. Host fidelity of A. lucorum differed between seasons, with 87.9% of spring hosts also used in the summer and 36.1% of summer hosts used in winter. In contrast, as little as 25.6% host plant species were shared between winter and spring. Annual herbaceous plants are most often used for overwintering, while perennial woody plants are relatively important for initial population build-up in the spring. Our study contributes to an improved understanding of evolutionary interactions between A. lucorum and its host plants and lays the groundwork for the design of population management strategies for this important pest in myriad crops. PMID:25692969

The Fleas (Siphonaptera) in Iran: Diversity, Host Range, and Medical Importance

PubMed Central

Maleki-Ravasan, Naseh; Solhjouy-Fard, Samaneh; Beaucournu, Jean-Claude; Laudisoit, Anne

2017-01-01

Background Flea-borne diseases have a wide distribution in the world. Studies on the identity, abundance, distribution and seasonality of the potential vectors of pathogenic agents (e.g. Yersinia pestis, Francisella tularensis, and Rickettsia felis) are necessary tools for controlling and preventing such diseases outbreaks. The improvements of diagnostic tools are partly responsible for an easier detection of otherwise unnoticed agents in the ectoparasitic fauna and as such a good taxonomical knowledge of the potential vectors is crucial. The aims of this study were to make an exhaustive inventory of the literature on the fleas (Siphonaptera) and range of associated hosts in Iran, present their known distribution, and discuss their medical importance. Methodology/Principal Findings The data were obtained by an extensive literature review related to medically significant fleas in Iran published before 31st August 2016. The flea-host specificity was then determined using a family and subfamily-oriented criteria to further realize and quantify the shared and exclusive vertebrate hosts of fleas among Iran fleas. The locations sampled and reported in the literature were primarily from human habitation, livestock farms, poultry, and rodents’ burrows of the 31 provinces of the country. The flea fauna were dominated by seven families, namely the Ceratophyllidae, Leptopsyllidae, Pulicidae, Ctenophthalmidae, Coptopsyllidae, Ischnopsyllidae and Vermipsyllidae. The hosts associated with Iran fleas ranged from the small and large mammals to the birds. Pulicidae were associated with 73% (56/77) of identified host species. Flea-host association analysis indicates that rodents are the common hosts of 5 flea families but some sampling bias results in the reduced number of bird host sampled. Analyses of flea-host relationships at the subfamily level showed that most vertebrates hosted fleas belgonging to 3 subfamilies namely Xenopsyllinae (n = 43), Ctenophthalminae (n = 20) and Amphipsyllinae (n = 17). Meriones persicus was infested by 11 flea subfamilies in the arid, rocky, mountainous regions and Xenopsyllinae were hosted by at least 43 mammal species. These findings place the Persian jird (M. persicus) and the Xenopsyllinae as the major vertebrate and vector hosts of flea-borne diseases in Iran including Yersinia pestis, the etiological agent of plague. We found records of at least seven vector-borne pathogenic agents that can potentially be transmitted by the 117 flea species (or subspecies) of Iran. Conclusions/Significance Herein, we performed a thorough inventary of the flea species and their associated hosts, their medical importance and geographic distribution throughout Iran. This exercise allowed assessing the diversity of flea species with the potential flea-borne agents transmission risk in the country by arranging published data on flea-host associations. This information is a first step for issuing public health policies and rodent-flea control campaigns in Iran as well as those interested in the ecology/epidemiology of flea-borne disease. PMID:28068343

Understanding the direction of evolution in Burkholderia glumae through comparative genomics.

PubMed

Lee, Hyun-Hee; Park, Jungwook; Kim, Jinnyun; Park, Inmyoung; Seo, Young-Su

2016-02-01

Members of the genus Burkholderia occupy remarkably diverse niches, with genome sizes ranging from ~3.75 to 11.29 Mbp. The genome of Burkholderia glumae ranges in size from ~5.81 to 7.89 Mbp. Unlike other plant pathogenic bacteria, B. glumae can infect a wide range of monocot and dicot plants. Comparative genome analysis of B. glumae strains can provide insight into genome variation as well as differential features of whole metabolism or pathways between multiple strains of B. glumae infecting the same host. Comparative analysis of complete genomes among B. glumae BGR1, B. glumae LMG 2196, and B. glumae PG1 revealed the largest departmentalization of genes onto separate replicons in B. glumae BGR1 and considerable downsizing of the genome in B. glumae LMG 2196. In addition, the presence of large-scale evolutionary events such as rearrangement and inversion and the development of highly specialized systems were found to be related to virulence-associated features in the three B. glumae strains. This connection may explain why this bacterium broadens its host range and reinforces its interaction with hosts.

Host-Derived CD70 Suppresses Murine Graft-versus-Host Disease by Limiting Donor T Cell Expansion and Effector Function.

PubMed

Leigh, Nicholas D; O'Neill, Rachel E; Du, Wei; Chen, Chuan; Qiu, Jingxin; Ashwell, Jonathan D; McCarthy, Philip L; Chen, George L; Cao, Xuefang

2017-07-01

Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative treatment for hematologic and immunologic diseases. However, graft-versus-host disease (GVHD) may develop when donor-derived T cells recognize and damage genetically distinct normal host tissues. In addition to TCR signaling, costimulatory pathways are involved in T cell activation. CD27 is a TNFR family member expressed on T cells, and its ligand, CD70, is expressed on APCs. The CD27/CD70 costimulatory pathway was shown to be critical for T cell function and survival in viral infection models. However, the role of this pathway in allo-HCT is previously unknown. In this study, we have examined its contribution in GVHD pathogenesis. Surprisingly, Ab blockade of CD70 after allo-HCT significantly increases GVHD. Interestingly, whereas donor T cell- or bone marrow-derived CD70 plays no role in GVHD, host-derived CD70 inhibits GVHD as CD70 -/- hosts show significantly increased GVHD. This is evidenced by reduced survival, more severe weight loss, and increased histopathologic damage compared with wild-type hosts. In addition, CD70 -/- hosts have higher levels of proinflammatory cytokines TNF-α, IFN-γ, IL-2, and IL-17. Moreover, accumulation of donor CD4 + and CD8 + effector T cells is increased in CD70 -/- versus wild-type hosts. Mechanistic analyses suggest that CD70 expressed by host hematopoietic cells is involved in the control of alloreactive T cell apoptosis and expansion. Together, our findings demonstrate that host CD70 serves as a unique negative regulator of allogeneic T cell response by contributing to donor T cell apoptosis and inhibiting expansion of donor effector T cells. Copyright © 2017 by The American Association of Immunologists, Inc.

An Update on Host-Pathogen Interplay and Modulation of Immune Responses during Orientia tsutsugamushi Infection.

PubMed

Díaz, Fabián E; Abarca, Katia; Kalergis, Alexis M

2018-04-01

The obligate intracellular bacterium Orientia tsutsugamushi is the causative agent of scrub typhus in humans, a serious mite-borne disease present in a widespread area of endemicity, which affects an estimated 1 million people every year. This disease may exhibit a broad range of presentations, ranging from asymptomatic to fatal conditions, with the latter being due to disseminated endothelial infection and organ injury. Unique characteristics of the biology and host-pathogen interactions of O. tsutsugamushi , including the high antigenic diversity among strains and the highly variable, short-lived memory responses developed by the host, underlie difficulties faced in the pursuit of an effective vaccine, which is an imperative need. Other factors that have hindered scientific progress relative to the infectious mechanisms of and the immune response triggered by this bacterium in vertebrate hosts include the limited number of mechanistic studies performed on animal models and the lack of genetic tools currently available for this pathogen. However, recent advances in animal model development are promising to improve our understanding of host-pathogen interactions. Here, we comprehensively discuss the recent advances in and future perspectives on host-pathogen interactions and the modulation of immune responses related to this reemerging disease, highlighting the role of animal models. Copyright © 2018 American Society for Microbiology.

Revisiting the Evolution of Mycobacterium bovis

PubMed Central

Mostowy, Serge; Inwald, Jackie; Gordon, Steve; Martin, Carlos; Warren, Rob; Kremer, Kristin; Cousins, Debby; Behr, Marcel A.

2005-01-01

Though careful consideration has been placed towards genetic characterization of tubercle bacillus isolates causing disease in humans, those causing disease predominantly among wild and domesticated mammals have received less attention. In contrast to Mycobacterium tuberculosis, whose host range is largely specific to humans, M. bovis and “M bovis-like” organisms infect a broad range of animal species beyond their most prominent host in cattle. To determine whether strains of variable genomic content are associated with distinct distributions of disease, the DNA contents of M. bovis or M. bovis-like isolates from a variety of hosts were investigated via Affymetrix GeneChip. Consistent with previous genomic analysis of the M. tuberculosis complex (MTC), large sequence polymorphisms of putative diagnostic and biological consequence were able to unambiguously distinguish interrogated isolates. The distribution of deleted regions indicates organisms genomically removed from M. bovis and also points to structured genomic variability within M. bovis. Certain genomic profiles spanned a variety of hosts but were clustered by geography, while others associated primarily with host type. In contrast to the prevailing assumption that M. bovis has broad host capacity, genomic profiles suggest that distinct MTC lineages differentially infect a variety of mammals. From this, a phylogenetic stratification of genotypes offers a predictive framework upon which to base future genetic and phenotypic studies of the MTC. PMID:16159772

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

PubMed

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.

Chayote mosaic virus, a New Tymovirus Infecting Cucurbitaceae.

PubMed

Bernal, J J; Jiménez, I; Moreno, M; Hord, M; Rivera, C; Koenig, R; Rodríguez-Cerezo, E

2000-10-01

ABSTRACT Chayote mosaic virus (ChMV) is a putative tymovirus isolated from chayote crops in Costa Rica. ChMV was characterized at the host range, serological, and molecular levels. ChMV was transmitted mechanically and induced disease symptoms mainly in Cucurbitaceae hosts. Asymptomatic infections were detected in other host families. Serologically, ChMV is related to the Andean potato latent virus (APLV) and the Eggplant mosaic virus (EMV), both members of the genus Tymovirus infecting solanaceous hosts in the Caribbean Basin and South America. The sequence of the genomic RNA of ChMV was determined and its genetic organization was typical of tymoviruses. Comparisons with other tymoviral sequences showed that ChMV was a new member of the genus Tymovirus. The phylogenetic analyses of the coat protein gene were consistent with serological comparisons and positioned ChMV within a cluster of tymoviruses infecting mainly cucurbit or solanaceous hosts, including APLV and EMV. Phylogenetic analyses of the replicase protein gene confirmed the close relationship of ChMV and EMV. Our results suggest that ChMV is related to two tymoviruses (APLV and EMV) of proximal geographical provenance but with different natural host ranges. ChMV is the first cucurbit-infecting tymovirus to be fully characterized at the genomic level.

Single Mutations in the VP2 300 Loop Region of the Three-Fold Spike of the Carnivore Parvovirus Capsid Can Determine Host Range.

PubMed

Allison, Andrew B; Organtini, Lindsey J; Zhang, Sheng; Hafenstein, Susan L; Holmes, Edward C; Parrish, Colin R

2016-01-15

Sylvatic carnivores, such as raccoons, have recently been recognized as important hosts in the evolution of canine parvovirus (CPV), a pandemic pathogen of domestic dogs. Although viruses from raccoons do not efficiently bind the dog transferrin receptor (TfR) or infect dog cells, a single mutation changing an aspartic acid to a glycine at capsid (VP2) position 300 in the prototype raccoon CPV allows dog cell infection. Because VP2 position 300 exhibits extensive amino acid variation among the carnivore parvoviruses, we further investigated its role in determining host range by analyzing its diversity and evolution in nature and by creating a comprehensive set of VP2 position 300 mutants in infectious clones. Notably, some position 300 residues rendered CPV noninfectious for dog, but not cat or fox, cells. Changes of adjacent residues (residues 299 and 301) were also observed often after cell culture passage in different hosts, and some of the mutations mimicked changes seen in viruses recovered from natural infections of alternative hosts, suggesting that compensatory mutations were selected to accommodate the new residue at position 300. Analysis of the TfRs of carnivore hosts used in the experimental evolution studies demonstrated that their glycosylation patterns varied, including a glycan present only on the domestic dog TfR that dictates susceptibility to parvoviruses. Overall, there were significant differences in the abilities of viruses with alternative position 300 residues to bind TfRs and infect different carnivore hosts, demonstrating that the process of infection is highly host dependent and that VP2 position 300 is a key determinant of host range. Although the emergence and pandemic spread of canine parvovirus (CPV) are well documented, the carnivore hosts and evolutionary pathways involved in its emergence remain enigmatic. We recently demonstrated that a region in the capsid structure of CPV, centered around VP2 position 300, varies after transfer to alternative carnivore hosts and may allow infection of previously nonsusceptible hosts in vitro. Here we show that VP2 position 300 is the most variable residue in the parvovirus capsid in nature, suggesting that it is a critical determinant in the cross-species transfer of viruses between different carnivores due to its interactions with the transferrin receptor to mediate infection. To this end, we demonstrated that there are substantial differences in receptor binding and infectivity of various VP2 position 300 mutants for different carnivore species and that single mutations in this region can influence whether a host is susceptible or refractory to virus infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Single Mutations in the VP2 300 Loop Region of the Three-Fold Spike of the Carnivore Parvovirus Capsid Can Determine Host Range

PubMed Central

Organtini, Lindsey J.; Zhang, Sheng; Hafenstein, Susan L.; Holmes, Edward C.

2015-01-01

ABSTRACT Sylvatic carnivores, such as raccoons, have recently been recognized as important hosts in the evolution of canine parvovirus (CPV), a pandemic pathogen of domestic dogs. Although viruses from raccoons do not efficiently bind the dog transferrin receptor (TfR) or infect dog cells, a single mutation changing an aspartic acid to a glycine at capsid (VP2) position 300 in the prototype raccoon CPV allows dog cell infection. Because VP2 position 300 exhibits extensive amino acid variation among the carnivore parvoviruses, we further investigated its role in determining host range by analyzing its diversity and evolution in nature and by creating a comprehensive set of VP2 position 300 mutants in infectious clones. Notably, some position 300 residues rendered CPV noninfectious for dog, but not cat or fox, cells. Changes of adjacent residues (residues 299 and 301) were also observed often after cell culture passage in different hosts, and some of the mutations mimicked changes seen in viruses recovered from natural infections of alternative hosts, suggesting that compensatory mutations were selected to accommodate the new residue at position 300. Analysis of the TfRs of carnivore hosts used in the experimental evolution studies demonstrated that their glycosylation patterns varied, including a glycan present only on the domestic dog TfR that dictates susceptibility to parvoviruses. Overall, there were significant differences in the abilities of viruses with alternative position 300 residues to bind TfRs and infect different carnivore hosts, demonstrating that the process of infection is highly host dependent and that VP2 position 300 is a key determinant of host range. IMPORTANCE Although the emergence and pandemic spread of canine parvovirus (CPV) are well documented, the carnivore hosts and evolutionary pathways involved in its emergence remain enigmatic. We recently demonstrated that a region in the capsid structure of CPV, centered around VP2 position 300, varies after transfer to alternative carnivore hosts and may allow infection of previously nonsusceptible hosts in vitro. Here we show that VP2 position 300 is the most variable residue in the parvovirus capsid in nature, suggesting that it is a critical determinant in the cross-species transfer of viruses between different carnivores due to its interactions with the transferrin receptor to mediate infection. To this end, we demonstrated that there are substantial differences in receptor binding and infectivity of various VP2 position 300 mutants for different carnivore species and that single mutations in this region can influence whether a host is susceptible or refractory to virus infection. PMID:26512077

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

PubMed

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.

Simulation optimization of spherical non-polar guest recognition by deep-cavity cavitands

PubMed Central

Wanjari, Piyush P.; Gibb, Bruce C.; Ashbaugh, Henry S.

2013-01-01

Biomimetic deep-cavity cavitand hosts possess unique recognition and encapsulation properties that make them capable of selectively binding a range of non-polar guests within their hydrophobic pocket. Adamantane based derivatives which snuggly fit within the pocket of octa-acid deep cavity cavitands exhibit some of the strongest host binding. Here we explore the roles of guest size and attractiveness on optimizing guest binding to form 1:1 complexes with octa-acid cavitands in water. Specifically we simulate the water-mediated interactions of the cavitand with adamantane and a range of simple Lennard-Jones guests of varying diameter and attractive well-depth. Initial simulations performed with methane indicate hydrated methanes preferentially reside within the host pocket, although these guests frequently trade places with water and other methanes in bulk solution. The interaction strength of hydrophobic guests increases with increasing size from sizes slightly smaller than methane to Lennard-Jones guests comparable in size to adamantane. Over this guest size range the preferential guest binding location migrates from the bottom of the host pocket upwards. For guests larger than adamantane, however, binding becomes less favorable as the minimum in the potential-of-mean force shifts to the cavitand face around the portal. For a fixed guest diameter, the Lennard-Jones well-depth is found to systematically shift the guest-host potential-of-mean force to lower free energies, however, the optimal guest size is found to be insensitive to increasing well-depth. Ultimately our simulations show that adamantane lies within the optimal range of guest sizes with significant attractive interactions to match the most tightly bound Lennard-Jones guests studied. PMID:24359375

Infectious Diseases,

DTIC Science & Technology

1980-02-29

was of importance in arresting the disease. On the other hand, tuberculous patients may develop a sarcoidosis -like hypersensitivity to vitamin D; if...action of vitamin D and become hypercalcemic, as in sarcoidosis . Normal quantities of vitamins and other nutrients help to maintain host resistance at

THE INFECTIVITY OF CRYPTOSPORIDIUM PARVUM IN HEALTHY VOLUNTEERS

EPA Science Inventory

Background. Small numbers of Cryptosporidium parvum oocysts can contaminate even treated drinking water, and ingestion of oocysts can cause diarrheal disease in normal as well as immunocompromised hosts. Since the number of organisms necessary to cause infection in humans is unkn...

Blue phase liquid crystal phase transition for cyano compound chiral nematic liquid crystal mixtures with three two-ring core structures and chiral dopant concentrations

NASA Astrophysics Data System (ADS)

Shin, Jaesun; Kim, Beomjong; Jung, Wansu; Fahad, Mateen; Park, SangJin; Hong, Sung-Kyu

2017-05-01

Blue phase (BP) temperature range of a chiral nematic liquid crystal (LC) mixture is dependent upon the host nematic LC chemical structure and chiral dopant concentration. In this study, we investigated BP phase transition behaviour and helical twisting power (HTP) using three chiral dopant concentrations of cyano compound chiral nematic LC mixtures incorporating three two-ring core structures in the host nematic LCs. The effect of the host nematic LC core structure, HTP and chiral dopant concentrations were considered on BP temperature ranges, for two types of complete BPI and BPII without isotropic phase (Iso) and two types of coexistence state of BPI+Iso and BPII+Iso.

A spatial and genetic analysis of Cowbird host selection

USGS Publications Warehouse

Hahn, D.C.; Sedgwick, J.A.; Painter, I.S.; Casna, N.J.; Morrison, Michael L.; Hall, Linnea S.; Robinson, Scott K.; Rothstein, Stephen I.; Hahn, D. Caldwell; Rich, Terrell D.

1999-01-01

Our study of brood parasitism patterns in forest communities revealed the egg-laying frequency and host selection patterns of female cowbirds. By integrating molecular genetics and spatial data, we have the first published estimate on cowbird laying rates in field studies. The 29 females in the study laid only 1-5 eggs each, much lower than previous estimates from captive cowbirds and extrapolations from ovarian development in capture/recapture studies that had suggested that as many as 40 eggs could be laid per individual cowbird. Cowbird females also were shown for the first time to lay significantly more eggs within the home range areas they established rather than outside the home range. No patterns were uncovered for individual females preferentially parasitizing particular host species

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

PubMed

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.

All five host-range variants of Xanthomonas citri carry one pthA homolog with 17.5 repeats that determines pathogenicity on citrus, but none determine host-range variation.

PubMed

Al-Saadi, Abdulwahid; Reddy, Joseph D; Duan, Yong P; Brunings, Asha M; Yuan, Qiaoping; Gabriel, Dean W

2007-08-01

Citrus canker disease is caused by five groups of Xanthomonas citri strains that are distinguished primarily by host range: three from Asia (A, A*, and A(w)) and two that form a phylogenetically distinct clade and originated in South America (B and C). Every X. citri strain carries multiple DNA fragments that hybridize with pthA, which is essential for the pathogenicity of wide-host-range X. citri group A strain 3213. DNA fragments that hybridized with pthA were cloned from a representative strain from all five groups. Each strain carried one and only one pthA homolog that functionally complemented a knockout mutation of pthA in 3213. Every complementing homolog was of identical size to pthA and carried 17.5 nearly identical, direct tandem repeats, including three new genes from narrow-host-range groups C (pthC), A(w) (pthAW), and A* (pthA*). Every noncomplementing paralog was of a different size; one of these was sequenced from group A* (pthA*-2) and was found to have an intact promoter and full-length reading frame but with 15.5 repeats. None of the complementing homologs nor any of the noncomplementing paralogs conferred avirulence to 3213 on grapefruit or suppressed avirulence of a group A* strain on grapefruit. A knockout mutation of pthC in a group C strain resulted in loss of pathogenicity on lime, but the strain was unaffected in ability to elicit an HR on grapefruit. This pthC- mutant was fully complemented by pthA, pthB, or pthC. Analysis of the predicted amino-acid sequences of all functional pthA homologs and nonfunctional paralogs indicated that the specific sequence of the 17th repeat may be essential for pathogenicity of X. citri on citrus.

History, geography and host use shape genomewide patterns of genetic variation in the redheaded pine sawfly (Neodiprion lecontei).

PubMed

Bagley, Robin K; Sousa, Vitor C; Niemiller, Matthew L; Linnen, Catherine R

2017-02-01

Divergent host use has long been suspected to drive population differentiation and speciation in plant-feeding insects. Evaluating the contribution of divergent host use to genetic differentiation can be difficult, however, as dispersal limitation and population structure may also influence patterns of genetic variation. In this study, we use double-digest restriction-associated DNA (ddRAD) sequencing to test the hypothesis that divergent host use contributes to genetic differentiation among populations of the redheaded pine sawfly (Neodiprion lecontei), a widespread pest that uses multiple Pinus hosts throughout its range in eastern North America. Because this species has a broad range and specializes on host plants known to have migrated extensively during the Pleistocene, we first assess overall genetic structure using model-based and model-free clustering methods and identify three geographically distinct genetic clusters. Next, using a composite-likelihood approach based on the site frequency spectrum and a novel strategy for maximizing the utility of linked RAD markers, we infer the population topology and date divergence to the Pleistocene. Based on existing knowledge of Pinus refugia, estimated demographic parameters and patterns of diversity among sawfly populations, we propose a Pleistocene divergence scenario for N. lecontei. Finally, using Mantel and partial Mantel tests, we identify a significant relationship between genetic distance and geography in all clusters, and between genetic distance and host use in two of three clusters. Overall, our results indicate that Pleistocene isolation, dispersal limitation and ecological divergence all contribute to genomewide differentiation in this species and support the hypothesis that host use is a common driver of population divergence in host-specialized insects. © 2016 John Wiley & Sons Ltd.

How understanding immunology contributes to managing CMV disease in immunosuppressed patients: now and in future.

PubMed

Sissons, J G Patrick; Wills, Mark R

2015-06-01

Several decades of research on human cytomegalovirus (HCMV) and the principal mammalian cytomegaloviruses which to varying degrees act as models of HCMV infection, particularly murine, guinea pig and rhesus CMV, have led to the recognition of the CMVs as interesting models of persistent infection with a large and complex DNA virus, which have been highly informative of the immunology and molecular pathogenesis of the virus-host relationship in the normal host. However, it is appropriate to ask how this relative wealth of knowledge has influenced the understanding and management of clinical disease due to HCMV. This article considers the immunology of cytomegalovirus in the normal human host, and the interrelated issue of the sites of HCMV latency and mechanisms of reactivation in the myeloid cell lineage, and in related in vitro model systems. The way in which this site of latency conditions the immune response, and emerging information on the special features of the adaptive immune response to HCMV during latency are also considered. Examples of HCMV disease associated with acquired immunosuppression, principally in the context of transplantation, but also as a consequence of HIV/AIDS and immune reconstitution inflammatory syndrome, are then discussed, with a particular emphasis on how understanding the immunology of persistent infection may contribute to managing CMV disease now and in future.

Patterns of co-speciation and host switching in primate malaria parasites.

PubMed

Garamszegi, László Zsolt

2009-05-22

The evolutionary history of many parasites is dependent on the evolution of their hosts, leading to an association between host and parasite phylogenies. However, frequent host switches across broad phylogenetic distances may weaken this close evolutionary link, especially when vectors are involved in parasites transmission, as is the case for malaria pathogens. Several studies suggested that the evolution of the primate-infective malaria lineages may be constrained by the phylogenetic relationships of their hosts, and that lateral switches between distantly related hosts may have been occurred. However, no systematic analysis has been quantified the degree of phylogenetic association between primates and their malaria parasites. Here phylogenetic approaches have been used to discriminate statistically between events due to co-divergence, duplication, extinction and host switches that can potentially cause historical association between Plasmodium parasites and their primate hosts. A Bayesian reconstruction of parasite phylogeny based on genetic information for six genes served as basis for the analyses, which could account for uncertainties about the evolutionary hypotheses of malaria parasites. Related lineages of primate-infective Plasmodium tend to infect hosts within the same taxonomic family. Different analyses testing for congruence between host and parasite phylogenies unanimously revealed a significant association between the corresponding evolutionary trees. The most important factor that resulted in this association was host switching, but depending on the parasite phylogeny considered, co-speciation and duplication may have also played some additional role. Sorting seemed to be a relatively infrequent event, and can occur only under extreme co-evolutionary scenarios. The concordance between host and parasite phylogenies is heterogeneous: while the evolution of some malaria pathogens is strongly dependent on the phylogenetic history of their primate hosts, the congruent evolution is less emphasized for other parasite lineages (e.g. for human malaria parasites). Estimation of ancestral states of host use along the phylogenetic tree of parasites revealed that lateral transfers across distantly related hosts were likely to occur in several cases. Parasites cannot infect all available hosts, and they should preferentially infect hosts that provide a similar environment for reproduction. Marginally significant evidence suggested that there might be a consistent variation within host ranges in terms of physiology. The evolution of primate malarias is constrained by the phylogenetic associations of their hosts. Some parasites can preserve a great flexibility to infect hosts across a large phylogenetic distance, thus host switching can be an important factor in mediating host ranges observed in nature. Due to this inherent flexibility and the potential exposure to various vectors, the emergence of new malaria disease in primates including humans cannot be predicted from the phylogeny of parasites.

GENETICS OF HOST RANGE IN LEPIDOPTERA

USDA-ARS?s Scientific Manuscript database

The genetic basis of complex, ecologically relevant traits is not well known for any organism. The question is particularly compelling where closely-related species have diverged radically in their adaptation to the environment. Differences in host plant use among moths and butterflies often provi...

3-Dimensional Geologic Modeling Applied to the Structural Characterization of Geothermal Systems: Astor Pass, Nevada, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siler, Drew L; Faulds, James E; Mayhew, Brett

2013-04-16

Geothermal systems in the Great Basin, USA, are controlled by a variety of fault intersection and fault interaction areas. Understanding the specific geometry of the structures most conducive to broad-scale geothermal circulation is crucial to both the mitigation of the costs of geothermal exploration (especially drilling) and to the identification of geothermal systems that have no surface expression (blind systems). 3-dimensional geologic modeling is a tool that can elucidate the specific stratigraphic intervals and structural geometries that host geothermal reservoirs. Astor Pass, NV USA lies just beyond the northern extent of the dextral Pyramid Lake fault zone near the boundarymore » between two distinct structural domains, the Walker Lane and the Basin and Range, and exhibits characteristics of each setting. Both northwest-striking, left-stepping dextral faults of the Walker Lane and kinematically linked northerly striking normal faults associated with the Basin and Range are present. Previous studies at Astor Pass identified a blind geothermal system controlled by the intersection of west-northwest and north-northwest striking dextral-normal faults. Wells drilled into the southwestern quadrant of the fault intersection yielded 94°C fluids, with geothermometers suggesting a maximum reservoir temperature of 130°C. A 3-dimensional model was constructed based on detailed geologic maps and cross-sections, 2-dimensional seismic data, and petrologic analysis of the cuttings from three wells in order to further constrain the structural setting. The model reveals the specific geometry of the fault interaction area at a level of detail beyond what geologic maps and cross-sections can provide.« less

Molecular epidemiology identifies only a single rabies virus variant circulating in complex carnivore communities of the Serengeti

PubMed Central

Lembo, T; Haydon, D.T; Velasco-Villa, A; Rupprecht, C.E; Packer, C; Brandão, P.E; Kuzmin, I.V; Fooks, A.R; Barrat, J; Cleaveland, S

2007-01-01

Understanding the transmission dynamics of generalist pathogens that infect multiple host species is essential for their effective control. Only by identifying those host populations that are critical to the permanent maintenance of the pathogen, as opposed to populations in which outbreaks are the result of ‘spillover’ infections, can control measures be appropriately directed. Rabies virus is capable of infecting a wide range of host species, but in many ecosystems, particular variants circulate among only a limited range of potential host populations. The Serengeti ecosystem (in northwestern Tanzania) supports a complex community of wild carnivores that are threatened by generalist pathogens that also circulate in domestic dog populations surrounding the park boundaries. While the combined assemblage of host species appears capable of permanently maintaining rabies in the ecosystem, little is known about the patterns of circulation within and between these host populations. Here we use molecular phylogenetics to test whether distinct virus–host associations occur in this species-rich carnivore community. Our analysis identifies a single major variant belonging to the group of southern Africa canid-associated viruses (Africa 1b) to be circulating within this ecosystem, and no evidence for species-specific grouping. A statistical parsimony analysis of nucleoprotein and glycoprotein gene sequence data is consistent with both within- and between-species transmission events. While likely differential sampling effort between host species precludes a definitive inference, the results are most consistent with dogs comprising the reservoir of rabies and emphasize the importance of applying control efforts in dog populations. PMID:17609187

Genomes of three facultatively symbiotic Frankia sp. strainsreflect host plant biogeography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Normand, Philippe; Lapierre, Pascal; Tisa, Louis S.

2006-02-01

Filamentous actinobacteria from the genus Frankia anddiverse woody trees and shrubs together form N2-fixing actinorhizal rootnodule symbioses that are a major source of new soil nitrogen in widelydiverse biomes 1. Three major clades of Frankia sp. strains are defined;each clade is associated with a defined subset of plants from among theeight actinorhizal plant families 2,3. The evolution arytrajectoriesfollowed by the ancestors of both symbionts leading to current patternsof symbiont compatibility are unknown. Here we show that the competingprocesses of genome expansion and contraction have operated in differentgroups of Frankia strains in a manner that can be related to thespeciation ofmore » the plant hosts and their geographic distribution. Wesequenced and compared the genomes from three Frankia sp. strains havingdifferent host plant specificities. The sizes of their genomes variedfrom 5.38 Mbp for a narrow host range strain (HFPCcI3) to 7.50Mbp for amedium host range strain (ACN14a) to 9.08 Mbp for a broad host rangestrain (EAN1pec.) This size divergence is the largest yet reported forsuch closely related bacteria. Since the order of divergence of thestrains is known, the extent of gene deletion, duplication andacquisition could be estimated and was found to be inconcert with thebiogeographic history of the symbioses. Host plant isolation favoredgenome contraction, whereas host plant diversification favored genomeexpansion. The results support the idea that major genome reductions aswell as expansions can occur in facultatively symbiotic soil bacteria asthey respond to new environments in the context of theirsymbioses.« less

Molecular epidemiology identifies only a single rabies virus variant circulating in complex carnivore communities of the Serengeti.

PubMed

Lembo, T; Haydon, D T; Velasco-Villa, A; Rupprecht, C E; Packer, C; Brandão, P E; Kuzmin, I V; Fooks, A R; Barrat, J; Cleaveland, S

2007-09-07

Understanding the transmission dynamics of generalist pathogens that infect multiple host species is essential for their effective control. Only by identifying those host populations that are critical to the permanent maintenance of the pathogen, as opposed to populations in which outbreaks are the result of 'spillover' infections, can control measures be appropriately directed. Rabies virus is capable of infecting a wide range of host species, but in many ecosystems, particular variants circulate among only a limited range of potential host populations. The Serengeti ecosystem (in northwestern Tanzania) supports a complex community of wild carnivores that are threatened by generalist pathogens that also circulate in domestic dog populations surrounding the park boundaries. While the combined assemblage of host species appears capable of permanently maintaining rabies in the ecosystem, little is known about the patterns of circulation within and between these host populations. Here we use molecular phylogenetics to test whether distinct virus-host associations occur in this species-rich carnivore community. Our analysis identifies a single major variant belonging to the group of southern Africa canid-associated viruses (Africa 1b) to be circulating within this ecosystem, and no evidence for species-specific grouping. A statistical parsimony analysis of nucleoprotein and glycoprotein gene sequence data is consistent with both within- and between-species transmission events. While likely differential sampling effort between host species precludes a definitive inference, the results are most consistent with dogs comprising the reservoir of rabies and emphasize the importance of applying control efforts in dog populations.

Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole.

PubMed

Bennett, Gordon M; Moran, Nancy A

2015-08-18

Many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. A model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and Buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. Symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritable symbiosis. Receiving less attention are potential negative ramifications of symbiotic alliances. In the short run, symbionts impose metabolic costs. Over evolutionary time, hosts evolve dependence beyond the original benefits of the symbiosis. Symbiotic partners enter into an evolutionary spiral that leads to irreversible codependence and associated risks. Host adaptations to symbiosis (e.g., immune-system modification) may impose vulnerabilities. Symbiont genomes also continuously accumulate deleterious mutations, limiting their beneficial contributions and environmental tolerance. Finally, the fitness interests of obligate heritable symbionts are distinct from those of their hosts, leading to selfish tendencies. Thus, genes underlying the host-symbiont interface are predicted to follow a coevolutionary arms race, as observed for genes governing host-pathogen interactions. On the macroevolutionary scale, the rapid evolution of interacting symbiont and host genes is predicted to accelerate host speciation rates by generating genetic incompatibilities. However, degeneration of symbiont genomes may ultimately limit the ecological range of host species, potentially increasing extinction risk. Recent results for the aphid-Buchnera symbiosis and related systems illustrate that, whereas heritable symbiosis can expand ecological range and spur diversification, it also presents potential perils.