Myxidium volitans sp. nov., a parasite of the gallbladder of the fish, Dactylopterus volitans (Teleostei: Triglidae) from the Brazilian Atlantic coast: morphology and pathology

Myxidium volitans sp. nov. (Myxozoa: Myxidiidae) parasitizing the hypertrophied green-brownish gallbladder of the teleost Dactylopterus volitans, collected in the Atlantic coast near Niterói, Brazil was described based on ultrastructural studies. The spores were fusiform, sometimes slightly crescent-shaped on average 21.7 ± 0.3 µm (mean ± standard deviation) (n = 50) long and 5.6 ± 0.4 µm (n = 30) wide. The spore wall was thin and smooth, comprising two equally-sized valves joined by a hardly visible sutural ridge. Spores containing two pyriform polar capsules (PC) (5.0 ± 0.4 × 2.3 ± 0.3 µm) (n = 30) are situated in each extremity of the spore. The PC wall was composed of hyaline layer (0.20-0.29 µm thick) and by a thin external granular layer. Each PC contains a polar filament (PF) with irregular arrangements that was projected from its apical region to the bases of PC and coiled laterally from bases to the tip of PC. Some regular striations and S-like structures in the periphery of the PFs with four-five irregular sections were observed. Based on the spore morphology, ultrastructural differences and the specificity of the host we describe this parasite as a new myxosporidian, named M. volitans sp. nov.

Light and electron microscopy of Myxobolus sciades n. sp. (Myxozoa), a parasite of the gills of the Brazilian fish Sciades herzbergii (Block, 1794) (Teleostei: Ariidae)

A myxosporean parasite in the gill lamellae of the freshwater teleost fish, Sciades herzbergii (Ariidae) (Block, 1794), from the Poti River (Northeast of Brazil) was described by light and electron microscopy studies. Polysporic histozoic cyst-like plasmodia containing several life-cycle stages, including mature spores, were observed. The spores were pyriform and uninucleate, measuring 9.15 ± 0.39 μm (n = 50) long, 4.36 ± 0.23 μm (n = 25) wide and 2.61 ± 0.31 μm (n = 25) thick. Elongated pyriform polar capsules (PC) were of equal size (4.44 ± 0.41 μm long and 1.41 ± 0.42 μm in diameter) and each contained a polar filament with 9-10 coils obliquely arranged in relation to the axis of PC. The PC wall was composed of two layers of different electron densities. Histological analysis revealed the close contact of the cyst-like plasmodia with the basal portion of the epithelial gill layer, which exhibited some alterations in the capillary vessels. Based on the morphological and ultrastructural differences, the similarity of the spore features to those of the genus Myxobolus and the specificity of this host to previously described species, we describe a new species named Myxobolus sciades n. sp. in this study.

Helminth parasite communities of allopatric populations of the frog Leptodactylus podicipinus from Pantanal, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Immune response to Haemonchus contortus and Haemonchus placei in sheep and its role on parasite specificity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphological changes and parasite load of the adrenal from dogs with visceral leishmaniasis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

New host records and a checklist of fishes infected with Austrodiplostomum compactum (Digenea: Diplostomidae) in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Parasitoid-host interaction: sensory structures involved in the parasitism behavior of Bracon vulgaris (Hymenoptera: Braconidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The relationships between parasite intensity, locomotor performance, and body condition in adult toads (Rhinella icterica) from the wild

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Acromyrmex charruanus: a new inquiline social parasite species of leaf-cutting ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

New record of Pelecitus sp (Nematoda, Onchocercidae) as a parasite of Athene cunicularia (Strigiformes, Strigidae) in southeastern Brazil

The aim of this study was to report the burrowing owl Athene cunicularia as a new host for the filarid nematode Pelecitus sp. in southeastern Brazil for the first time, as well as reporting the occurrence of this nematode species in the body cavity, near the cervical air sac and lung region. This study contributes towards knowledge of parasitism in Brazilian wild birds and an anatomical region of the host as an infection site for Pelecitus sp.

Host Specificity of Calyptospora funduli (Apicomplexa: Calyptosporidae) in Atheriniform Fishes

Calyptospora funduli has a broad host specificity, infecting at least 7 natural and 10 additional experimental definitive hosts, all atheriniform fishes within 5 families, but most in the genus Fundulus. Barriers, apparently innate ones, prevent any development of C. funduli in perciform fishes but allow incomplete or abnormal development of the parasite in a few unnatural atheriniform hosts. In the freshwater species Fundulus olivaceus and Fundulus notti, these abnormalities consisted of asynchronous development, degeneration of the parasite in early stages of development, and the formation of numerous macrophage aggregates. Rivulus marmoratus has the ability to eliminate infections with a granulomatous inflammatory response. Additional barriers that limit natural infections of C. funduli in other hosts include feeding behavior, environmental conditions, and geographic isolation.

Parasitoids (Braconidae) associated with Anastrepha (Tephritidae) in host fruits on the Southern coast of Bahia, Brazil

Among the organisms acting in the natural biological control of tephritids, members of the family Braconidae are the most active form of natural parasite, and in Neotropical regions, members of Opiinae are the main control agents of Anastrepha. The objective of this work was to discover the percentage of parasitism and the species of braconid associated with fruit trees growing in cities on the southern coast of Bahia. During the period of August, 2005 to March, 2008, hosts fruits of fruit flies from several plant species were collected and from the fruits the following species of Anastrepha were obtained: A. fraterculus, A. obliqua, A. bahiensis, A. serpentina, A. sororcula and A. zenildae. Of the total of 838 specimens of braconids, 21.36% were of the species Utetes anastrephae (Viereck), obtained from yellow mombin, carambola, guava, mango and pitanga; 4.42% were of the species Asobara anastrephae (Muesebeck) obtained from the fruits of the yellow mombin, carambola and guava, and only one example of Opius bellus Gahan (0.12%) that came from a guava sample. The species Doryctobracon areolatus (Szepligeti) (74.10%) was predominant and emerged from puparia from all the host fruits collected, probably due to the greater efficiency of this species in locating tephritid larvae. The mean percentage of parasitism by Anastrepha spp. was 4.45%.

Galactose Recognition by the Apicomplexan Parasite Toxoplasma gondii

Toxosplasma gondii is the model parasite of the phylum Apicomplexa, which contains numerous obligate intracellular parasites of medical and veterinary importance, including Eimeria, Sarcocystis, Cryptosporidium, Cyclospora, and Plasmodium species. Members of this phylum actively enter host cells by a multistep process with the help of microneme protein (MIC) complexes that play important roles in motility, host cell attachment, moving junction formation, and invasion. T. gondii (Tg)MIC1-4-6 complex is the most extensively investigated microneme complex, which contributes to host cell recognition and attachment via the action of TgMIC1, a sialic acid-binding adhesin. Here, we report the structure of TgMIC4 and reveal its carbohydrate-binding specificity to a variety of galactose-containing carbohydrate ligands. The lectin is composed of six apple domains in which the fifth domain displays a potent galactose-binding activity, and which is cleaved from the complex during parasite invasion. We propose that galactose recognition by TgMIC4 may compromise host protection from galectin-mediated activation of the host immune system.

Analysis of Schistosoma mansoni genes shared with Deuterostomia and with possible roles in host interactions

Abstract Background: Schistosoma mansoni is a blood helminth parasite that causes schistosomiasis, a disease that affects 200 million people in the world. Many orthologs of known mammalian genes have been discovered in this parasite and evidence is accumulating that some of these genes encode proteins linked to signaling pathways in the parasite that appear to be involved with growth or development, suggesting a complex co-evolutionary process. Results: In this work we found 427 genes conserved in the Deuterostomia group that have orthologs in S. mansoni and no members in any nematodes and insects so far sequenced. Among these genes we have identified Insulin Induced Gene (INSIG), Interferon Regulatory Factor (IRF) and vasohibin orthologs, known to be involved in mammals in mevalonate metabolism, immune response and angiogenesis control, respectively. We have chosen these three genes for a more detailed characterization, which included extension of their cloned messages to obtain full-length sequences. Interestingly, SmINSIG showed a 10-fold higher expression in adult females as opposed to males, in accordance with its possible role in regulating egg production. SmIRF has a DNA binding domain, a tryptophan-rich N-terminal region and several predicted phosphorylation sites, usually important for IRF activity. Fourteen different alternatively spliced forms of the S. mansoni vasohibin (SmVASL) gene were detected that encode seven different protein isoforms including one with a complete C-terminal end, and other isoforms with shorter C-terminal portions. Using S. mansoni homologs, we have employed a parsimonious rationale to compute the total gene losses/gains in nematodes, arthropods and deuterostomes under either the Coelomata or the Ecdysozoa evolutionary hypotheses; our results show a lower losses/gains number under the latter hypothesis. Conclusion: The genes discussed which are conserved between S. mansoni and deuterostomes, probably have an ancient origin and were lost in Ecdysozoa, being still present in Lophotrochozoa. Given their known functions in Deuterostomia, it is possible that some of them have been co-opted to perform functions related (directly or indirectly) to host adaptation or interaction with host signaling processes.

Aggression and its function as a hub mediating host defense against the slavemaking ant Protomognathus americanus

In meiner Dissertation beschäftigte ich mich mit unterschiedlichen Verteidungsstrategien, derenrnEffektivität und Evolution, der Ameisenart Temnothorax longispinosus (“Sklaven”), gegenüberrneinem sozialen Parasiten - der nahverwandten, sklavenhaltenden Art Protomognathusrnamericanus (“Sklavenhalter”). Wir entdeckten eine neue Kategorie der Verteidigungsstrategie,rnwelche es dem Wirten ermöglicht, flexibel auf die nicht vorhersagbaren Angriffe des Parasitenrnzu reagieren. Darüber hinaus erforschten wir, wie die Wirte ihre kollektive Verteidigung an einernVielzahl unterschiedlicher Angreifer anpassen können. Wir konnten feststellen, dass Wirte in derrnLage sind ihre kollektive Verteidigung dem Grad der Bedrohung anzupassen. Dies weist daraufrnhin, dass Selektion die Verteidigung gegen unterschiedliche Typen von Angreifern voneinanderrnunabhängig beeinflussen könnte. In einer dritten Studie belegten wir experimentell, dass diernParasiten die Evolution der Kolonieaggressivität der Wirtsart direkt beeinflussen. Die letztenrnbeiden Publikationen beschäftigten sich mit Sklavenrebellion, einer rätselhaftenrnVerteidigungsstrategie, da noch unklar ist, wie eine Eigenschaft von nicht reproduzierendenrnIndividuen vererbt werden kann. In einer Metaanalyse konnten wir die weite Verbreitung undrnhohe Variabilität dieser Eigenschaft dokumentieren, und fanden Hinweise, dassrnVerwandtenselektion eine mögliche Erklärung für die Evolution dieses Merkmals darstellenrnkönnte.