Six new and one previously described species of Pseudorhabdosynochus (Monogenoidea, Diplectanidae) infecting the gills of groupers (Perciformes, Serranidae) from the Pacific coasts of Mexico and Panama

Six new and 1 previously described species of Pseudorhabdosynochus (Diplectanidae) are described and/or reported from the gill lamellae of 5 serranid (Perciformes) fish species from the Pacific waters in Guerrero State of Mexico and Panama City, Panama. These species are Pseudorhabdosynochus guerreroensis n. sp. from the Pacific mutton hamlet Alphestes inmaculatus Breder (type host), rivulated mutton hamlet Alphestes multiguttatus (Günther), and spotted grouper Epinephelus analogus Gill from Mexico; Pseudorhabdosynochus urceolus n. sp. from the Pacific graysby Cephalopholis panamensis (Steindachner) from Taboga Island in Panama; Pseudorhabdosynochus spirani n. sp. from the starry grouper Epinephelus labriformis (Jenyns) from Mexico and the Perlas Archipelago and Taboga Island in Panama; Pseudorhabdosynochus fulgidus n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus tabogaensis n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus anulus n. sp. from E. labriformis from Mexico and Taboga Island (type locality) in Panama; and Pseudorhabdosynochus amplidiscatum (Bravo-Hollis, 1954) Kritsky and Beverley-Burton, 1986 from E. analogus and E. labriformis from Mexico and the Perlas Archipelago and Taboga Island in Panama. All new species are mainly distinguished from other species of the genus by the shape and size of the sclerotized vagina and haptoral structures. The present specimens of Alphestes, Cephalopholis, and Epinephelus spp. represent new host records and Panama represents a new geographic record for species of Pseudorhabdosynochus. The apparent common feature supporting a close similarity of these diplectanids is a single, secondary ejaculatory bulb with thickened wall.     

Variability in the taxonomic characters of Black Sea gyrodactylids (Monogenea)

Variability of the haptoral hard parts of four Black Sea Gyrodactylus species (G. alviga Dmitrieva & Gerasev, 2000; G. crenilabri Zaika, 1966; G. flesi Malmberg, 1957; G. sphinx Dmitrieva & Gerasev, 2000) was studied in relation to season, host and geographical variability. A discriminant analysis was carried out on the measurements of 14 characters of the haptor of all four species. The haptoral hard parts of the investigated gyrodactylids decrease in size with an increase in water temperature. It is known that life-span of gyrodactylids is negatively correlated with water temperature and they exhibit peak intensities at low temperature. At the same time, life-span is considered to be a general indicator of a favourable environment. Therefore, high water temperature is not apparently advantageous for gyrodactylids. In the case of low marine salinity, in adapted species the sizes of the haptoral hard parts are larger at lower levels of salinity and vice versa for typical marine species. Lastly, in specimens parasitising the primary host, these features are larger than in those parasitising a secondary host. It is possible to say that, in general, the more favourable the environment for gyrodactylids the larger their haptoral hard parts. Unfavourable environmental conditions reduce the time of embryogenesis, which has a dual effect on gyrodactylids: positive in relation to their reproduction (by increasing the reproduction rate) and negative in relation to their development (by decreasing the size of the haptoral hard parts).     

Scanning electron microscope studies of miracidia suggest introgressive hybridization between Schistosoma haematobium and S. haematobium x S. mattheei in the Eastern Transvaal

Schistosoma haematobium miracidia were collected from a locality with a high prevalence of human infection with the animal parasite, S. mattheei, which hybridizes with S. haematobium, and from 2 localities with negligible infection rates. The terebratoria of the miracidia from these localities were compared with each other, with laboratory maintained S. haematobium and with four populations of S. mattheei by means of scanning electron microscopy. It was found that the terebratorial membrane of certain of the S. haematobium miracidia from the locality with a high S. mattheei prevalence in humans, resembled the more intricate membrane of S. mattheei. This suggests introgressive hybridization between S. haematobium and S. haematobium x S. mattheei.     

A new species of <Emphasis Type="Italic">Tinrovia</Emphasis> Mamaev, 1987 (Monogenea: Microcotylidae) from the deep-sea fish <Emphasis Type="Italic">Notacanthus bonaparte</Emphasis> Risso (Notacanthiformes: Notacanthidae) in the Western Mediterranean and the North East Atlantic

A new microcotylid, Tinrovia mamaevi n. sp. (Monogenea: Polyopisthocotylea), is described from the gills of Notacanthus bonaparte Risso (Notacanthiformes: Notacanthidae), sampled in the Western Mediterranean and North East Atlantic. This species is allocated to the subfamily Syncoelicotylinae Mamaev & Zubchenko, 1978 due to the possession of a symmetrical haptor with two separate frills. The clamps in T. mamaevi n. sp. are of the “microcotylid” type, arranged in two distinct lateral haptoral frills; the genital atrium and the copulatory organ are armed and the vaginal pore is unarmed. The new species differs from the type- and only species of the genus, T. papiliocauda Mamaev, 1987, in having a shorter and narrower haptor with a smaller number of clamps. Clamps are also smaller in the new species, testes are more numerous, the genital atrium is smaller, divided into two lateral lobes (instead of five) with a smaller number of spines and the eggs have a short and a long filament (instead of two short filaments). The host species and locality of T. mamaevi n. sp. also differ as T. papiliocauda which was recorded in Notacanthus sexspinis Richardson from the South Pacific.     

<Emphasis Type="Italic">Ligophorus llewellyni</Emphasis> n. sp. (Monogenea: Ancyrocephalidae) from the redlip mullet <Emphasis Type="Italic">Liza haematocheilus</Emphasis> (Temminck &; Schlegel) introduced into the Black Sea from the Far East

Ligophorus llewellyni n. sp. (Ancyrocephalidae: Ligophorus Euzet & Suriano, 1977) is described from the gills of Liza haematocheilus (Temminck & Schlegel) introduced into the Black Sea from the Far East. Ligophorus llewellyni is closely related to L. pilengas Sarabeev & Balbuena, 2004, which parasitises the same host species. The two species differ in the morphology of the accessory piece of the copulatory organ and in some of the characters of the haptoral hard-parts. The morphometric variability of L. llewellyni and in its morphologically most similar congeners from the Black Sea is studied. Correlations between 30 morphometric characters of the haptoral hard-parts and the significance of each for species differentiation are examined. It is suggested that only 22 characters are useful as diagnostic criteria permitting the differentiation of morphologically similar species of Ligophorus.     

Intraspecific competition and mating between fungal strains of the anther smut Microbotryum violaceum from the host plants Silene latifolia and S. dioica

Abstract We studied intraspecific competition and assortative mating between strains of the anther smut fungus Microbotryum violaceum from two of its host species, Silene latifolia and S. dioica . Specifically, we investigated whether strains from allopatric host populations have higher competitive ability on their native host species and show positive assortative mating. In general, strains isolated from S. latifolia outcompeted strains isolated from S. dioica on both host species, but in female hosts, heterotypic dikaryons (i.e., dikaryons composed of a haploid strain originating from S. latifolia and a haploid strain originating from S. dioica ) were most successful in competition. Furthermore, the latency period was significantly shorter for heterokaryons that contained at least one strain originating from S. latifolia , compared to heterokaryons that only contained strains originating from S. dioica . The frequencies of conjugations between strains originating from S. latifolia were much higher than conjugation frequencies between strains originating from S. dioica . A significant positive correlation was detected between the relative success of strains in competition and in conjugation, suggesting that success of a strain in competition might be partly determined by its swiftness of mating. In addition, reciprocal differences within heterotypic crosses revealed a significant effect of fungal mating type, with mating type a₁ being the main determinant of mating pace. The observed differences in infection success, conjugation rate, and latency period in favor of strains from S. latifolia relative to strains from S. dioica on both host species are discussed in an evolutionary context of opportunities for the maintenance of differentiation between different formae speciales upon secondary contact.     

Persistent bacterial infections: the interface of the pathogen and the host immune system

Persistent bacterial infections involving Mycobacterium tuberculosis, Salmonella enterica serovar Typhi (S. typhi) and Helicobacter pylori pose significant public-health problems. Multidrug-resistant strains of M. tuberculosis and S. typhi are on the increase, and M. tuberculosis and S. typhi infections are often associated with HIV infection. This review discusses the strategies used by these bacteria during persistent infections that allow them to colonize specific sites in the host and evade immune surveillance. The nature of the host immune response to this type of infection and the balance between clearance of the pathogen and avoidance of damage to host tissues are also discussed.     

Geographic and within-population structure in variable resistance to parasite species and strains in a vertebrate host

Host resistance to parasites and parasite infectivity may be subject to significant genetically determined variation within species. However, relatively little is known of how this variability is structured in natural vertebrate populations and their macroparasites. A laboratory experiment on host susceptibility-parasite infectivity variation in a wildlife host-parasite system (subspecies of the anuran X. laevis and their polystome flatworms), including 33 pairwise allopatric and sympatric host-parasite combinations (three parasite geographical isolates x 11 host full-sibling families, n=600), revealed a complex pattern of infection success. Results amongst host sibships from different localities suggested that infection success was subject to a highly significant locality x parasite isolate interaction. Within localities, a highly significant sibship x isolate interaction also occurred in one of two groups of sibships examined. The existence of such interactions suggests a potential for frequency-dependent, Red Queen-like selection. Interaction between locality and isolate was partly due to higher infection levels in sympatric combinations, consistent with a general pattern of host-specific adaptation. However, some allopatric combinations produced unpredictably high infection levels, resulting in very asymmetrical cross-infectivity patterns (where the reciprocal cross-infections produced negligible infection). This phylogeographically structured host-parasite system may, therefore, sometimes generate local parasite strains with high infectivity to allopatric hosts. Secondary contact between populations could thus result in significant, and unequal, transfer of parasites.     

Onchocerca eberhardi n. sp. (Nematoda: Filarioidea) from sika deer in Japan; relationships between species parasitic in cervids and bovids in the Holarctic region

Onchocerca eberhardi n. sp. from the sika deer, Cervus nippon, in Japan is described. Adult worms lived in the carpal ligament; infection reached high levels (up to 25 female and 16 male worms in a single carpal limb). Skin dwelling microfilariae were mainly found in the ears. Prevalence of infection was 81% at the type locality, Mt. Sobo, in Kyushu. The new material was compared to the 31 species of Onchocerca presently known. Onchocerca eberhardi n. sp. females were characterized by a long slender anterior end and a thin esophagus < or =1 mm long with no or only a slight glandular region. The vulva was located near the level of the mid-esophagus and the cuticle had transverse external ridges and internal striae (two striae between adjoining ridges). The most similar species were O. stilesi (re-examined), O. lienalis, and to a lesser extent O. gutturosa, all from bovids (cattle). Two main lineages of Onchocerca are recognized in cervids with either primitive or with derived characteristics (as exemplified by the new species). The species in both lineages are not restricted to cervids but are also found in bovids in the Holarctic region, suggesting that the species diversified in the two host groups simultaneously, when these host groups lived in the some geographic area.     

Synopsis of the species of Chloromyxum Mingazinni, 1890 (Myxozoa: Myxosporea: Chloromyxidae)

A synopsis of the species of Chloromyxum Mingazinni, 1890 (Myxozoa: Myxosporea: Chloromyxidae) is presented, including 140 nominal species. For each species the most relevant morphological and morphometric characteristics are indicated. Included are data on the site of infection within the host, the original host and the host locality, plus a full bibliography of the original records for these species. A diagrammatic illustration of a spore of each species is also provided.     

A new species of Sprostoniella Bychowsky and Nagibina, 1967 (Monogenea: Capsalidae) from Chaetodipterus zonatus (Osteichthyes: Ephippidae) in Chamela Bay, Mexico

A new species of Sprostoniella is described from the gills of Chaetodipterus zonatus in Chamela Bay, on the west coast of Mexico. The new species differs from the 2 previously described congeners by having smaller testes each of which is not nearly as long as the ovary. It further differs from the type species, Sprostoniella multitestis, by having a poorly developed pair of accessory sclerites and the cecal diverticula are not confluent posteriorly. The new species also differs from Sprostoniella micrancyra, the other species of the genus, by having a shorter peduncle, the glands of Goto are smaller than the testes and ovary, and by having a slightly different haptoral structure, with 1 pair of hamuli rather than 2 pairs, and 1 central haptoral loculus instead of 2 loculi.     

Host specificity is linked to intraspecific variability in the genus Lamellodiscus (Monogenea)

SUMMARYWe investigated whether host specificity is linked to variability within species of Lamellodiscus monogeneans, which are gill ectoparasites of the Sparidae. We sampled fish parasites in the northeastern part of the Mediterranean Sea: 4 specialist species, using 1 single host species, and 3 generalist species, using 2 distinct host species. Intraspecific variability was assessed from 2 different datasets. Morphometric variability of the attachment organ, called the haptor, was estimated first from measurements of several sclerified haptoral parts on 102 individuals. Genetic variability was calculated based on comparisons of sequences derived from the first internal transcribed spacer (ITS-1) of nuclear ribosomal DNA of 62 individuals. Morphometric variances in the specialist versus generalist species were compared via principal component analysis and F-tests, and uncorrected genetic distances (p-distances) were estimated within each species. We showed that the inter-individual variance of morphometric characters, as well as p-distances, are clearly greater within generalist species than specialist ones. These findings suggest that a relative increase in morphological and molecular variability enhances the possibility to colonize new host species in monogeneans, and supports the hypothesis that intraspecific variability could be a potential determinant of host specificity.     

Acanthocephalus bufonis (Acanthocephala) from Bufo marinus (Bufonidae: Amphibia) in Hawaii.

During a survey of the helminth parasites of the introduced toad, Bufo marinus, on O'ahu, Hawaii, an acanthocephalan corresponding to Acanthocephalus bufonis (Shipley, 1903) was found in the intestinal tract. This is a new host and locality record for A. bufonis which has only previously been recorded from amphibians in the Orient. Possible mechanisms for the introduction of A. bufonis to Hawaii, and its transmission to the toad, are discussed. Almost 98% of toads were infected with a mean intensity of 28.6 acanthocephalans per infected toad. There was a significant negative correlation between host length and intensity of infection with subadult toads having significantly higher infection levels than adult male and female toads. Trunk length of both male and female acanthocephalans was significantly related to host length.     

Wall teichoic acids of Staphylococcus aureus limit recognition by the drosophila peptidoglycan recognition protein-SA to promote pathogenicity

The cell wall of gram-positive bacteria is a complex network of surface proteins, capsular polysaccharides and wall teichoic acids (WTA) covalently linked to Peptidoglycan (PG). The absence of WTA has been associated with a reduced pathogenicity of Staphylococcus aureus (S. aureus). Here, we assessed whether this was due to increased detection of PG, an important target of innate immune receptors. Antibiotic-mediated or genetic inhibition of WTA production in S. aureus led to increased binding of the non-lytic PG Recognition Protein-SA (PGRP-SA), and this was associated with a reduction in host susceptibility to infection. Moreover, PGRP-SD, another innate sensor required to control wild type S. aureus infection, became redundant. Our data imply that by using WTA to limit access of innate immune receptors to PG, under-detected bacteria are able to establish an infection and ultimately overwhelm the host. We propose that different PGRPs work in concert to counter this strategy.     

Inhibition of host translation in encephalomyocarditis virus-infected L cells: a novel mechanism

Encephalomyocarditis virus induced a rapid shutoff of host translation in mouse L cells shortly after infection and before viral proteins were made in detectable amounts. This kinetic pattern is similar to that seen in poliovirus-infected HeLa cells. However, the mechanisms of host shutoff are different in these two cases, for no reduction in the ability of lysates from encephalomyocarditis virus-infected L cells to translate capped mRNAs was observed. Instead, a change in the subcellular distribution of one or more initiation factors was seen. In particular, cap recognition activity in the high-speed supernatant fraction (S200) prepared from cell lysates increased threefold as a result of virus infection. The significance of this observation in terms of possible shutoff mechanisms is discussed. Inasmuch as the rapid host shutoff is not induced in at least four other cell types by encephalomyocarditis virus infection, it may be concluded that host shutoff mechanisms not only vary within the picornavirus group, but also depend upon the particular cell type employed.     

Natural host range and prevalence of the genus strongwellsea (Zygomycota: entomophthorales) in denmark

The natural occurrence and host range of species of the insect pathogenic fungal genus Strongwellsea [Zygomycota: Entomophthorales] were studied by extensive sampling and examination of adult Diptera [Cyclorrhapha]. The host range for Strongwellsea spp. was significantly enlarged. Three families were documented as new hosts: Muscidae (three species), Calliphoridae (one species), and Sarcophagidae (one species). Further, within the family Anthomyiidae six new host species were recorded and three new host species were documented in the Fanniidae. Strongwellsea castrans was identified as the pathogen in the Anthomyiids, while records from Fanniidae belonged to S. magna. The records of S. magna were the first outside the type locality (California). Primary conidia morphology indicated that muscid and calliphorid species were infected by three undescribed species of Strongwellsea. For the sarcophagid fly, no conidia were encountered, so the Strongwellsea species could not be identified. The tested sampling methods had each different advantages. Sweep netting and diagnosis in situ gave the best opportunity to sample a high number of infected dipterans per time unit spend, while sweep netting followed by incubation in the laboratory was the only method for the documentation of resting spores. The prevalence of S. castrans in the cabbage root fly Delia radicum was obtained by two methods: Samples collected by sweep net and incubated and water trap samples. Water trap captures gave higher prevalences of conidial infections than sweep-net captures. Measured prevalences of Strongwellsea spp. infections are therefore highly dependent on sampling method. The occurrence of resting spores of S. castrans in D. radicum was almost exclusively restricted to females and varied during the season. In samples from 1988 through 1993, no infected females in June contained resting spores, while 43.0% of the S. castrans-infected females from samples in August contained resting spores. During September and October, a decreasing proportion of S. castrans-infected D. radicum contained resting spores. The results document that species from the genus Strongwellsea are common fungal pathogens of adult flies from different families, occasionally with high prevalences. It also appears that the two described species of Strongwellsea, S. castrans and S. magna, have a range of dipterous host species that may always belong to a single family, Anthomyiidae and Fanniidae, respectively. Our data shows also that the host family Muscidae may be exploited by two new species of Strongwellsea. Copyright 1999 Academic Press.     

On the ontogeny of the haptor and the evolution of the Monogenea

Data on the ontogeny of the posterior haptor of monogeneans were obtained from more than 150 publications and summarised. These data were plotted into diagrams showing evolutionary capacity levels based on the theory of a progressive evolution of marginal hooks, anchors and other attachment components of the posterior haptor in the Monogenea (Malmberg, 1986). 5 + 5 unhinged marginal hooks are assumed to be the most primitive monogenean haptoral condition. Thus the diagrams were founded on a 5 + 5 unhinged marginal hook evolutionary capacity level, and the evolutionary capacity levels of anchors and other haptoral attachement components were arranged according to haptoral ontogenetical sequences. In the final plotting diagram data on hosts, type of spermatozoa, oncomiracidial ciliation, sensilla pattern and protonephridial systems were also included. In this way a number of correlations were revealed. Thus, for example, the number of 5 + 5 marginal hooks correlates with the most primitive monogenean type of spermatozoon and with few sensillae, many ciliated cells and a simple protonephridial system in the oncomiracidium. On the basis of the reviewed data it is concluded that the ancient monogeneans with 5 + 5 unhinged marginal hooks were divided into two main lines, one retaining unhinged marginal hooks and the other evolving hinged marginal hooks. Both main lines have recent representatives at different marginal hook evolutionary capacity levels, i.e. monogeneans retaining a haptor with only marginal hooks. For the main line with hinged marginal hooks the name Articulon-choinea n. subclass is proposed. Members with 8 + 8 hinged marginal hooks only are here called Proanchorea n. superord. Monogeneans with unhinged marginal hooks only are here called Ananchorea n. superord. and three new families are erected for its recent members: Anonchohapteridae n. fam., Acolpentronidae n. fam. and Anacanthoridae n. fam. (with 7 + 7, 8 + 8 and 9 + 9 unhinged marginal hooks, respectively). Except for the families of Articulonchoinea (e.g. Acanthocotylidae, Gyrodactylidae, Tetraonchoididae) Bychowsky's (1957) division of the Monogenea into the Oligonchoinea and Polyonchoinea fits the proposed scheme, i.e. monogeneans with unhinged marginal hooks form one old group, the Oligonchoinea, which have 5 + 5 unhinged marginal hooks, and the other group form the Polyonchoinea, which (with the exception of the Hexabothriidae) has a greater number (7 + 7, 8 + 8 or 9 + 9) of unhinged marginal hooks. It is proposed that both these names, Oligonchoinea (sensu mihi) and Polyonchoinea (sensu mihi), will be retained on one side and Articulonchoinea placed on the other side, which reflects the early monogenean evolution. Except for the members of Ananchorea [Polyonchoinea], all members of the Oligonchoinea and Polyonchoinea have anchors, which imply that they are further evolved, i.e. have passed the 5 + 5 marginal hook evolutionary capacity level (Malmberg, 1986). There are two main types of anchors in the Monogenea: haptoral anchors, with anlages appearing in the haptor, and peduncular anchors, with anlages in the peduncle. There are two types of haptoral anchors: peripheral haptoral anchors, ontogenetically the oldest, and central haptoral anchors. Peduncular anchors, in turn, are ontogenetically younger than peripheral haptoral anchors. There may be two pairs of peduncular anchors: medial peduncular anchors, ontogentically the oldest, and lateral peduncular anchors. Only peduncular (not haptoral) anchors have anchor bars. Monogeneans with haptoral anchors are here called Mediohaptanchorea n. superord. and Laterohaptanchorea n. superord. or haptanchoreans. All oligonchoineans and the oldest polyonchoineans are haptanchoreans. Certain members of Calceostomatidae [Polyonchoinea] are the only monogeneans with both (peripheral) haptoral and peduncular anchors (one pair). These monogeneans are here called Mixanchorea n. superord. Polyonchoineans with peduncular anchors and unhinged marginal hooks are here called the Pedunculanchorea n. superord. The most primitive pedunculanchoreans have only one pair of peduncular anchors with an anchor bar, while the most advanced have both medial and lateral peduncular anchors; each pair having an anchor bar. Certain families of the Articulonchoinea, the Anchorea n. superord., also have peduncular anchors (parallel evolution): only one family, the Sundanonchidae n. fam., has both medial and lateral peduncular anchors, each anchor pair with an anchor bar. Evolutionary lines from different monogenean evolutionary capacity levels are discussed and a new system of classification for the Monogenea is proposed.In agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. EditorIn agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. Editor