Type Host Research Articles

Acyclic cucurbit[n]uril type receptors: secondary versus tertiary amide arms

ABSTRACTTwo acyclic CB[n]-type hosts (1 and 2) which possess four 2° or 3° amide arms are reported. Host 2 has four 3° amide arms that exist as a mixture of E- and Z-isomers. 1H NMR was used to qualitatively investigate the binding properties of 1 and 2 which indicates they retain the essential binding features of macrocyclic CB[n] hosts. We measured the Ka values of 1 and 2 toward guests 6–14 by ITC. Neutral hosts 1 and 2 bind less tightly than tetraanionic hosts M1, ACB1, and ACB2. We attribute the lower Ka values to the absence of secondary ion-ion electrostatic interactions for host•guest complexes of 1 and 2. The secondary amide functionality on 1 decreases affinity by the formation of intramolecular NH•••O=C H-bonds. Tertiary amide host 2 binds even more weakly than 1 due to backfolding of the amide N-CH3-groups of 2 into its own cavity.

Insight into the species diversity of the quill mite genus Betasyringophiloidus Skoracki, 2011 (Prostigmata: Syringophilidae) on the basis of the DNA barcodes

Betasyringophiloidus Skoracki, 2011 is a genus of quill mites (Prostigmata: Syringophilidae) that is believed to contain mono-, steno- and polyxenous parasites associated with a wide range of passerine birds (Passeriformes) across the world. In this work we applied the DNA-barcode marker (mitochondrial cytochrome c oxidase subunit I gene fragment, COI) to verify whether Betasyringophiloidus schoeniclus (Skoracki, 2002) and Betasyringophiloidus seiuri (Clark, 1964) are actual steno- and polyxenous species associated with the currently recognised host ranges, or their populations are highly host-specific, cryptic species. Our results revealed that a population living on the Tristram's bunting Emberiza tristrami Swinhoe (Emberizidae) in Russia, so far classified as B. schoeniclus, is a new cryptic species Betasyringophiloidus emberizae sp. nov. Both topologies of the neighbor-joining and maximum likelihood phylogenetic trees as well as genetic distance (11.9% Kimura 2-parameter distance) (K2P) support species status of the mite population from E. tristrami. The same data support previously established conspecific status of B. seiuri found on the ovenbird Seiurus aurocapilla (Linnaeus) (Parulidae) (type host) and the northern waterthrush Parkesia noveboracensis (Gmelin) (Parulidae) and expand its range with a population found on a new host species Icterus pustulatus (Wagler) (Icteridae) with intraspecific K2P distance up to 1.9% and interpopulation distances ranging from 1.3 to 3.1%.

Occurrence of Podocotyle Dujardin, 1845 (Opecoelidae, Podocotylinae) in three species of deep-sea macrourids from the Gulf of Mexico and Caribbean Sea with an updated key to species and host-parasite checklist.

Podocotyle pearsei Manter, 1934 is documented from the intestine of Vaillant's grenadier, Bathygadus melanobranchus Vaillant (Macrouridae: Bathygadinae), collected from the northeastern and western Gulf of Mexico from 783-841 m depth. The finding of P. pearsei in B. melanobranchus represents the first originally published report of this genus from this host and the fifth documented host species for P. pearsei. We report three unidentified species of Podocotyle, represented by one individual each, from the intestine of the western Atlantic grenadier, Nezumia atlantica (Parr) (Macrouridae: Macrourinae), and from Bathygadus favosus Goode Bean (Macrouridae: Bathygadinae) found at 637 m, 710 m and 1,143 m depths in the northeastern Gulf of Mexico off Florida and from the Caribbean Sea off Colombia. We provide a checklist of the parasites known from the three macrourid species relevant to this study, comment on the biogeography of the five species of Podocotyle now known from the deep sea and discuss the low host specificity observed across this genus. The high number of fish hosts for Podocotyle (i.e. type hosts include at least 22 piscine families) encompassing a wide phylogenetic diversity and diet makes it unlikely that members of a single genus could evolve such a broad array of life histories (i.e. utilize dissimilar intermediate hosts), and we predict in the future that Podocotyle will be taxonomically divided up. Morphological and especially molecular work is needed for Podocotyle as well as for other digenean genera known to inhabit the deep sea. Podocotyle sp. 1 2 represent the first originally published reports of this genus from N. atlantica while Podocotyle sp. 3 represents the first report of this genus from B. favosus. Podocotyle koshari Nagaty, 1973 is declared a species inquirenda, and a dichotomous key to the 27 species of Podocotyle we recognize is provided.

Stable hole transport type host boosting the efficiency and lifetime of the exciplex host based phosphorescent organic light-emitting diodes

A strong hole transport type host (p-type host) for exciplex host application was developed for stable device lifetime in green phosphorescent organic light-emitting diodes. The hole transport type host, 3,3′-bis(5-phenylindolo[3,2-a]carbazol-12(5H)-yl)-1,1′-biphenyl (IDCzBP), was designed to have indolocarbazole unit for strong hole transport property and stability under positive polaron state. The IDCzBP worked as the p-type host in the exciplex host and extended the device lifetime of the green phosphorescent organic light-emitting diodes by 11 times with reference to conventional p-type host. Furthermore, the IDCzBP host had an efficiency boosting effect in the green devices. Analysis of the device behavior informed that the improved stability under positive polaron state is responsible for the upgraded device lifetime. A maximum external quantum efficiency of 20.3% and lifetime extension by 11 times were registered in the green phosphorescent organic light-emitting diodes with a host platform of IDCzBP embedded exciplex host.

Abstract 1514: Myeloid cell derived myeloperoxidase links cellular innate immunity to inhibition of NF-κB signaling in melanoma tumor cells

Abstract Myeloid-derived cells are considered the primary mediators of the cellular innate immune system where myeloperoxidase (MPO) is the major enzyme present in these cells. MPO is essential for fighting infections but little is known about the role of MPO in cancer. Using the murine melanoma cell line, B16F10, in an immune-competent orthotopic tumor model, tumor growth was compared in wild type (MPO+/+) and syngeneic MPO-deficient host (MPO-/-) mice. Survival studies demonstrated that B16F10 tumors grew slower in MPO+/+ animals (mean survival 27.4 days ± 4.5 days) compared to MPO-/- animals (mean survival 23.4 days ± 1.6 days; p ≤ 0.005). Using a specific and potent inhibitor of MPO, 4-aminobenzoic acid hydrazide (4ABAH), we pharmacologically mimicked the MPO-/- phenotype by continuously dosing MPO+/+ animals. B16F10 tumors grew faster in MPO+/+ animals treated with 4ABAH (mean survival 23.8 days ± 2.5 days; p ≤ 0.017). Utilizing intravital imaging with skinfold window chamber animal models, we evaluated in real-time the recruitment of MPO-expressing myeloid-derived cells during melanoma progression in MPO+/+ and MPO-/- animals. B16F10 tumor NF-κB signaling, and MPO-mediated activation from immune infiltrates were imaged simultaneously using a multi-spectral, multi-modal imaging strategy. Because NF-κB signaling is a central coordinator of the immune system and cancer development, the dynamics of NF-κB signaling in B16F10 tumor in vivo were assessed using a transcriptionally-activated NF-κB-promoter-driven Firefly luciferase reporter enabling real-time bioluminescent imaging and quantitative monitoring of NF-κB transcriptional activation. Mean NF-κB transcriptional activation within the tumor compartment in MPO-/- mice was 42.2% ± 1.6% greater compared to MPO+/+ animals. Intravital microscopy demonstrated heterogeneous activation levels of NF-κB within tumor cells in MPO+/+ animals. To explore whether the spatial heterogeneity was a consequence of myeloid-derived cell distribution within the microenvironment, myeloid-derived cells were labeled in vivo using an i.v. injection of fluorophore-labeled dextran and fluorophore-labeled αGr1 antibody. Remarkably, tumor cells in contact with myeloid cells in vivo demonstrated decreased NF-κB transcriptional activation compared to tumor cells not in contact with myeloid cells. These in vivo studies demonstrate that MPO-expressing myeloid-derived cells suppress NF-κB transcriptional activation within B16F10 tumors in a tight spatially-localized and proximity-dependent manner where MPO, expressed broadly by myeloid-derived cells, contributes to host protection and decreased tumor progression. We demonstrate that MPO-expressing myeloid-derived cells function as an anti-tumor component of the cellular innate immune response during early melanoma progression in a NF-κB-dependent manner. Citation Format: Tracy W. Liu, Seth T. Gammon, Ping Yang, David T. Fuentes, David Piwnica-Worms. Myeloid cell derived myeloperoxidase links cellular innate immunity to inhibition of NF-κB signaling in melanoma tumor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1514.

Distinctive site preference of the fish parasite Myxobolus cerebralis (Cnidaria, Myxozoa) during host invasion.

Here, we experimentally studied the site preference of Myxobolus cerebralis, one of the most pathogenic myxozoan (Cnidaria, Myxozoa) fish parasites, which causes whirling disease in salmonids. Parasite invasion was examined in three fish species with various susceptibility levels: the type host brown trout, the highly susceptible rainbow trout, and the non-susceptible gibel carp, in which parasite spores do not develop. We investigated the first two hours of fish invasion, and measured the site preference of triactinomyxons (TAMs) during attachment and penetration of fish in three body parts (gills, fins, skin). Infection prevalence and intensity were estimated using a species-specific nested PCR, optimised in the present study. The highest infection prevalence was detected in the most susceptible fish species, rainbow trout. Interestingly, higher prevalence was observed in gibel carp than in the type host, brown trout (95.2% vs. 85.7%). Considering body locations, remarkable differences were detected in infection intensities. The highest intensity was observed in fins, whereas skin was the least infected body part in every fish species examined. Infection prevalence and intensity did not differ significantly among fish species. Thus, we confirmed that M. cerebralis TAMs cannot discern fish species. Furthermore, we proved experimentally that fish fin is significantly more attractive to fish-invading parasite TAMs than gills or skin.

Mechanisms of oncogenic cell competition–Paths of victory

Cancer is a multistep process. In the early phases of this disease, mutations in oncogenes and tumor suppressors are thought to promote clonal expansion. These mutations can increase cell competitiveness, allowing tumor cells to grow within the tissue by eliminating wild type host cells. Recent studies have shown that cell competition can also function in later phases of cancer. Here, we examine the existing evidence linking cell competition and tumorigenesis. We focus on the mechanisms underlying cell competition and their contribution to disease pathogenesis.

Do Antibiotic Intramedullary Dowels Assist in Eradicating Infection in Two-Stage Resection for Septic Total Knee Arthroplasty?

BackgroundEvidence suggests approximately 40% of intramedullary (IM) canals are culture positive at resection for infected knee arthroplasty. While commonly utilized, no clinical data on the efficacy of antibiotic-eluding IM dowels exist. We quantified treatment success with and without the use of antibiotic-eluding IM dowels in two-stage treatment of periprosthetic knee infection using static and articulating antibiotic cement spacers. Methods109 consecutive patients who underwent two-stage treatment for periprosthetic knee infection were reviewed. Treatment failure, defined as repeat resection before reimplantation or recurrent infection within 6 months of reimplantation, was evaluated based on spacer type and use of IM dowels, accounting for infection type and systemic host and local extremity grade. ResultsAfter exclusions for confounds, articulating spacers without IM dowels were used in 49 (57.7%) cases, articulating spacers with IM dowels in 14 cases (16.5%), and static spacers with IM dowels in 22 (25.9%) cases. Treatment success regardless of infection classification was 85.7% for articulating spacers with IM dowels, 89.8% for articulating spacers without IM dowels, and 68.2% for static spacers with IM dowels (P = .074). In chronically infected poor hosts with compromised extremities, treatment success remained highest in patients with articulating spacers with (90.9%) or without (92.9%) IM dowels compared with static spacers with IM dowels (68.4%) (P = .061). ConclusionFindings suggest that the use of IM dowels did not enhance infection eradication above and beyond that observed for articulating spacers alone, including in the worst cases involving chronically infected poor hosts with compromised extremities.

Annotated catalogue of species of Angiostrongylus and the related genera Gallegostrongylus, Rodentocaulus and Stefanskostrongylus (Nematoda: Metastrongyloidea, Angiostrongylidae).

This catalogue is concerned with the closely related angiostrongylid genera Angiostrongylus, Gallegostrongylus, Rodentocaulus and Stefanskostrongylus. Three species, Angiostrongylus cantonensis, A. costaricensis and A. vasorum, have attracted most attention because of their importance in human and domestic animal disease. Many of the remaining species are poorly known and the number of valid taxa is unclear. The catalogue lists all nomenclaturally available and unavailable genus-group and species-group names that have been applied to the above genera and the species included in them, indicating their current nomenclatural status and providing the rigorous nomenclatural basis for future work. The catalogue lists 14 published and nomenclaturally available genus-group names, with the above four treated as valid, the other ten being junior synonyms. There are 42 published species-group names: 36 are valid, two are junior synonyms, four are nomenclaturally unavailable. One additional species, described in Chabaudistrongylus (synonym of Angiostrongylus), is listed as incertae sedis in Angiostrongylidae. Also listed are two unpublished collection names. The catalogue provides bibliographic details for all published names, and for available names provides locations of type material, details of type localities, geographic distributions and details of type and other hosts, both definitive and intermediate, to the extent known. The catalogue is a work of nomenclature, not a revisionary taxonomic work. No new names or new combinations are proposed. The apparently new family-group synonymy of Cardionematinae with Angiostrongylidae is introduced, as are four genus-group synonymies, three with Angiostrongylus and one with Stefaskostrongylus.

Revision of Acanthotaenia von Linstow, 1903 (Cestoda: Proteocephalidae), parasites of monitors (Varanus spp.), based on morphological and molecular data

A morphological and molecular phylogenetic study of proteocephalid tapeworms of the genus Acanthotaenia von Linstow, 1903, parasites of monitors (Varanidae), was carried out. The type species, A. shipleyi von Linstow, 1903, which was originally described based on an immature specimen from Sri Lanka, is redescribed based on new material from the type host, Varanus salvator, in Sri Lanka, Malaysia, and Vietnam, and its neotype is designated. In addition, Acanthotaenia susanae n. sp. is described from Varanus nebulosus in Vietnam. The new species differs from congeners by the large size of the scolex, width of the rostellum and the number of testes. New molecular data (sequences of lsrDNA and cox1) revealed Acanthotaenia paraphyletic with the inclusion of Australotaenia bunthangi de Chambrier & Scholz, 2012, a parasite of Enhydris enhydris (Ophidia: Homalopsidae) in Cambodia. Molecular data confirm a wide distribution of A. shipleyi (isolates from Malaysia and Vietnam were almost identical) and indicate a strict host specificity (oioxeny) of individual species of the genus. Type specimens of four species made it possible to supplement their morphological descriptions. A survey of all species of Acanthotaenia recognised as valid is presented and the following taxonomic changes are proposed: Acanthotaenia pythonis Wahid, 1968 described from the green python, Morelia viridis, in a zoo, is transferred to Kapsulotaenia as Kapsulotaenia pythonis (Wahid, 1968) n. comb., because it possesses intrauterine eggs grouped in capsules. Acanthotaenia gracilis (Beddard, 1913) from Varanus varius in Australia is considered to be species inquirenda because its original descriptions did not contain sufficient data for adequate circumscription and differentiation from congeners and type material was not available. Generic diagnosis of Acanthotaenia is amended and a key to its seven species is provided.

Bacterial nitrilases and their regulation.

Commercially, nitrilases are valuable biocatalysts capable of converting a diverse range of nitriles to carboxylic acids for the greener synthesis of chemicals and pharmaceuticals. Nitrilases are widespread in nature and are both important components of metabolic pathways and a response to environmental factors such as natural or manmade nitriles. Nitrilases are often grouped together on a genome in specific gene clusters that reflect these metabolic functions. Although nitrilase induction systems are still poorly understood, it is known that a powerful Rhodococcal transcription regulator system permits accumulation of intracellular nitrilase of up to 30-40% of total soluble protein in wild type Rhodococcous rhodochrous and host Streptomyces strains. Nitrilase expression inducer molecules encompass a broad range of aliphatic, aromatic and heteroaromatic nitriles, as well as some secondary and tertiary amides that are resistant to nitrilase degradation.

Description of Piscicapillaria bursata sp. nov. (Capillariidae) and Redescription of Parascarophis sphyrnae Campana-Rouget, 1955 (Cystidicolidae), Two Nematode Parasites of Hammerhead Sharks (Sphyrna spp.) off Australia.

Data on helminth parasites in hammerhead sharks are scarce and, therefore, new examinations of these hosts are needed to recognize the species composition of their parasites, including nematodes. Helminthological examinations of hammerhead sharks, Sphyrna lewini (Griffith et Smith) (209 specimens) and Sphyrna mokarran (Rüppell) (57 specimens) (Sphyrnidae, Carcharhiniformes), from off the northern coast of Australia revealed one new and one insufficiently known species of intestinal nematode parasites. These were studied with the use of light and scanning electron microscopy. Both nematode species are described. Piscicapillaria bursata sp. nov. (Capillariidae) from S. mokarran (type host) and S. lewini differs from its congeners mainly in the spicule length (330µm), body length of gravid females 12.80-21.26mm and in possessing a subterminal female anus. The specimens of Parascarophis sphyrnae Campana-Rouget, 1955 (Cystidicolidae) (type species of Parascarophis Campana-Rouget, 1955) collected from S. lewini made it possible to redescribe the female and, for the first time, to describe the male; the same species was also found in S. mokarran. Amended diagnosis of Parascarophis is provided. Parascarophis is mainly characterized by the presence of lateral alae, a unique feature within the Cystidicolidae, and by the cephalic structures (presence of a cuticular hood and a pair of anterolateral plate-like structures in the mouth). In addition to the discovery of a new nematode species, Pi. bursata sp. nov., the finding of Pa. sphyrnae in Australian waters represents a new geographical record of this parasite outside the Atlantic Ocean. The species of Parascarophis previously described from teleosts, P. bharatii Agrawal, 1965, P. oteroi Arya, 1992 and P. mulloidi Imam, Tawfik et Abdel Hady, 1982, are designated as species inquirendae and incertae sedis. The finding of P. sphyrnae in Australian waters represents a new geographical record of this parasite outside the Atlantic Ocean. Pa. sphyrnae had not been reported previously from beyond the Atlantic Ocean.

Morphological, Molecular, and Histopathological Data for Sebekia mississippiensis Overstreet, Self, and Vliet, 1985 (Pentastomida: Sebekidae) in the American Alligator, Alligator mississippiensis Daudin, and the Spotted Gar, Lepisosteus oculatus Winchell

Novel molecular data from both mitochondrial ( cytochrome c oxidase subunit 1) and ribosomal regions ( 18S, ITS1-5.8S, ITS2, and 28S) are provided for Sebekia mississippiensis Overstreet, Self, & Vliet, 1985 , a pentastome infecting the American alligator, Alligator mississippiensis Daudin, 1801, and the spotted gar, Lepisosteus oculatus Winchell, 1864. Adult and nymphal pentastomes are described from the lungs and liver of the type host, A. mississippiensis, collected from Mississippi, while additional nymphs are described from the esophageal lining of L. oculatus specimens collected from Louisiana. This sequencing data will facilitate more accurate identification of various life cycle stages of S. mississippiensis, enabling future work to resolve many ambiguities in the literature regarding this species. Additionally, histopathological data are provided from both the definitive and intermediate hosts.

Entertaining Visiting Friends and Relatives (VRF) in Destination Settings: a Cross-cultural Host Comparison

This study aims to examine whether there is a difference between two different host groups in terms of hosting styles in visiting friends and relatives (VFR) tourism. The study provides some insights into this issue by comparing hosting type, hosting length, expenditure type, etc. between Turkish and British hosts. A self-administered questionnaire was conducted among 238 Turkish and 224 British hosts who live in Didim, located in the Aegean Region of Turkey. Data were analyzed using descriptive statistics. The findings demonstrated that Turkish and British participants played an important role in hosting their friends and/or relatives. They also represented a large and underestimated part of VFR tourism with their expenditures and behaviors towards their guests. On the other hand, significant differences were found between Turkish and British hosts in which hosting their guests. Another finding of the study is that Turkish and British hosts and VFR travelers engage in activities in and around Didim. However, British hosts participated in activities more than Turkish hosts. In other words, this study found that British hosts contribute more to the local economy.

A new genus and four new species of dactylogyrids (Monogenea), gill parasites of pimelodid catfishes (Siluriformes: Pimelodidae) in South America and the reassignment of Urocleidoides megorchis Mizelle et Kritsky, 1969

Nanayella gen. n. is proposed to accommodate four new species of dactylogyrid monogeneans found on the gills of two species of pimelodid catfishes (Siluriformes) from the Amazon River basin in Peru and the Upper Paraná River basin in Brazil. Nanayella gen. n. is mainly characterised by the presence of modified hook pairs 5 and 6, which have a slender shank with slightly enlarged base, inconspicuous thumb, and straight point. Nanayella aculeatrium gen. n. et sp. n. (type species) from Sorubim lima (Bloch et Schneider) (type host) differs from its congeners mainly by possessing seven sclerotised spines on one side of circular ornamentation of the vaginal atrium. Nanayella fluctuatrium gen. n. et sp. n. is characterised by the presence of sclerotised undulations surrounding the circular ornamentation of the vaginal atrium. Nanayella amplofalcis gen. n. et sp. n. is typified by possessing hook pairs 1 and 2 with a robust, wide shank and a round, weakly sclerotised subunit at the base. Nanayella processusclavis gen. n. et sp. n. differs from congeners by the presence of a conspicuous posterior medial process on the dorsal bar. Urocleidoides megorchis Mizelle et Kritsky, 1969 described from the gills of S. lima in Brazil is transferred to Nanayella gen. n. as Nanayella megorchis comb. n. based on morphological and molecular evidence. Analyses of partial sequences of the 28S rRNA gene revealed all five species of the new genus to form a monophyletic clade within a bigger clade comprised of dactylogyrids of South American pimelodids.

Molecular phylogeny provides new insights on the taxonomy and composition of Lyperosomum Looss, 1899 (Digenea, Dicrocoeliidae) and related genera.

Lyperosomum Looss, 1899 is one of the largest genera of the Dicrocoeliidae and is one of the best examples of the systematic complexity and taxonomic instability within this family. We present the molecular analyses based on novel sequences of nuclear and mitochondrial genes obtained from 56 isolates of adult flukes and larval stages of dicrocoeliids belonging to Lyperosomum, Skrjabinus, Zonorchis as well as previously available sequence data. According to obtained results we propose to return Zonorchis clathratus and Z. petiolatus into Lyperosomum, and to recognize L. alagesi as a synonym of L. petiolatum. Our study shows that L. petiolatum commonly occurs in Europe in corvids as well as in several species of migratory songbirds, e.g. Sylvia atricapilla. At the same time, the Turdidae appear to host a distinct species of Lyperosomum. The phylogenetic analysis has clearly demonstrated the paraphylepic nature of Lyperosomum and indicated the need of its thorough revision preferably using specimens from type hosts and type territories of nominal species. In addition, inclusion of numerous not yet sequenced dicrocoeliid genera into future phylogenetic studies is necessary to clarify the interrelationships of taxa within the family and stabilize its system.

The genus Juglanconis (Diaporthales) on Pterocarya

Based on molecular phylogenetic analyses of a multigene matrix of partial nuSSU-ITS-LSU rDNA, cal, his, ms204, rpb1, rpb2, tef1 and tub2 sequences, recent European and Iranian collections of Melanconium pterocaryae from the type host, Pterocarya fraxinifolia, are shown to be distinct from the Japanese Melanconis pterocaryae from Pterocarya rhoifolia, and both are confirmed as closely related members of the recently described genus Juglanconis. Therefore, the new name Juglanconis japonica is proposed for Melanconis pterocaryae. As no type collection could be traced, Melanconium pterocaryae (syn. J. pterocaryae) is neotypified, described and illustrated, and it is recorded for Europe for the first time. During field surveys in natural stands of P. fraxinifolia in Guilan province (Iran), Juglanconis pterocaryae was consistently isolated from tissues affected by branch and trunk cankers, twig dieback and wood necrosis, indicating that it is the causal agent of these diseases. The external and internal symptoms associated with these trunk diseases are described and illustrated.

Phylogeny and taxonomy of Golovinomyces orontii revisited

Golovinomyces orontii is a common plurivorous powdery mildew species with wide host range and worldwide distribution, usually occurring as asexual morph. Ascomata (chasmothecia) are rarely formed on most hosts. Phylogenetic analyses based on rDNA ITS and 28S rDNA data of a wide range of powdery mildew collections of G. orontii s. lat. suggested a high degree of genetic heterogeneity of this species, which is undoubtedly not monophyletic. This study revealed that sequences retrieved from numerous collections referred to as G. orontii (s. lat.) split into three distinct main clusters, previously classified as groups 1 to 3. These groups have been genetically and morphologically analyzed, circumscribed, and named. One cluster (group 2), including a sequence retrieved from powdery mildew on the type host of Erysiphe orontii, Misopates orontium, constitutes G. orontii s. str. G. tabaci comb. nov. (≡ E. tabaci) is introduced for the second cluster in group 1 that is genetically and morphologically clearly distinct from G. orontii s. str. The third assemblage of sequences (group 3) comprises powdery mildews on hosts of the composite tribe Cichorieae, including Cichorium and Lactuca spp., and a wide range of hosts belonging to various other plant families for which the name G. bolayi sp. nov. is proposed. Euoidium longipes and Euoidium lycopersici, two additional powdery mildew species on solanaceous hosts, are briefly discussed and, based on previous phylogenetic analyses, reallocated to Golovinomyces. Oidium lactucae-debilis on Ixeris japonica in Asia is tentatively reduced to synonymy with G. sonchicola, i.e., it does not pertain to the G. orontii s. lat. complex. G. orontii s. lat. on Vinca spp. (Apocynaceae), mostly known as asexual morph, represents a separate species only distantly related to G. orontii s. str., which is described herein as Golovinomyces vincae sp. nov. Some re-examined collections on Vinca major from Germany misidentified as G. orontii turned out to belong to Ramularia vincae and represent first records of this species for Germany. Golovinomyces spadiceus is a further plurivorous Golovinomyces species discussed in this work, which, however, does not belong to the G. orontii complex.

Tapeworm discovery in elasmobranch fishes: quantifying patterns and identifying their correlates

Most parasites from known host species are yet to be discovered and described, let alone those from host species not yet known to science. Here, we use tapeworms of elasmobranchs to identify factors influencing their discovery and explaining the time lag between the descriptions of elasmobranch hosts and their respective tapeworm parasites. The dataset included 918 tapeworm species from 290 elasmobranch species. Data were analysed using linear mixed-effects models. Our findings indicated that we are currently in the midst of the greatest rate of discovery for tapeworms exploiting elasmobranchs. We identified tapeworm size, year of discovery of the type host, host latitudinal range and type locality of the parasite influencing most on the probability of discovery of tapeworms from elasmobranchs and the average time lag between descriptions of elasmobranchs and their tapeworms. The time lag between descriptions is decreasing progressively, but, at current rates and number of taxonomic experts, it will take two centuries to clear the backlog of undescribed tapeworms from known elasmobranch species. Given that the number of new elasmobranch species described each year is on the rise, we need to re-assess funding strategies to save elasmobranchs (and, thus, their tapeworm parasites) before they go extinct.

Molecular insights into the identification and phylogenetics of the cosmopolitan marine fish blood parasite, Haemogregarina bigemina (Adeleorina: Haemogregarinidae).

Haemogregarina bigemina is one of the most prevalent haemogregarines of marine fishes and has long been considered an enigmatic and cosmopolitan species. However, to determine whether H. bigemina truly represents a single global species, or whether it should be partitioned into several species or subspecies, and to confirm its taxonomic status among the Haemogregarina, molecular analysis is required. Here, we provide the first molecular characterisation of H. bigemina from one of its type hosts, Lipophrys pholis, in the UK using 18S rDNA sequences. Phylogenetic and p-distance comparisons of the newly generated H. bigemina sequences with those published from other haemogregarine taxa and related apicomplexans suggest that H. bigemina falls outside of the “Haemogregarina” clade as well as the Adeleorina altogether, forming a separate apicomplexan marine clade, and appears to be in fact more closely related to other non-haemogregarine Apicomplexa genera. Further work including sequences of H. bigemina and H. bigemina-like parasites observed from fishes in other localities is now needed to investigate this further.