Attachment of the peritrich epibiont Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia) to artificial substrates in a natural environment / Colonização de substratos artificiais pelo peritríquio epibionte Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia), em um ambiente natural

Peritrich ciliates are commonly found as epibionts, colonizing living organisms, or attached to non-living substrates in freshwater, estuarine and marine environments. Several species of peritrich epibionts are obligate, which means that they are able to only colonize other organisms, while others are facultative attaching to living or non-living substrates. The peritrich Zoothamnium intermedium is commonly found as epibiont on the copepod species Acartia tonsa and Eurytemora affinis in Chesapeake Bay, USA. Previous studies demonstrated that Z. intermedium is not able to attach to non-living substrates in the laboratory; with free-swimming stages (telotrochs) dying when living substrates are not available for colonization. The present study investigated the ability of Z. intermdium to colonize artificial substrates in the field. Observations were carried out while the peritrich ciliate was colonizing copepods in Rhode River, a tributary of Chesapeake Bay. Results demonstrated that four species of Zoothamnium were recovered from artificial substrates, but none of them was Z. intermedium. At the same time, Z. intermedium was colonizing adults and copepodites of E. affinis and A. tonsa during the whole study period. These results, in addition to laboratory observations, suggest that Z. intermedium is an obligate epibiont.

Ciliados peritríquios são normalmente encontrados como epibiontes, colonizando substratos vivos, ou em substratos inanimados em ambientes de água doce, estuarinos e marinhos. Muitas espécies de peritríquios epibiontes podem ser consideradas obrigatórias quando estão aptas a colonizar apenas substratos vivos, ou facultativos quando conseguem colonizar substratos vivos ou inanimados. A espécie de ciliado peritríquio Zoothamnium intermedium é encontrada colonizando os copépodos Acartia tonsa e Eurytemora affinis na Chesapeake Bay, EUA. Estudos preliminares demonstraram que Z. intermedium não consegue colonizar substratos inanimados em laboratório e que os estágios livre-natantes (telotróquios) morrem quando não estão expostos a algum substrato vivo. No presente estudo, foi investigada a habilidade de Z. intermedium colonizar substratos artificiais no campo. As observações foram realizadas no Rhode River, um afluente da Chesapeake Bay, enquanto Z. intermedium era encontrado colonizando copépodos. Os resultados demonstraram que quatro espécies de Zoothamnium colonizaram os substratos artificiais, mas nenhuma delas era Z. intermedium. No mesmo período, Z. intermedium foi encontrado colonizando copepoditos e adultos de A. tonsa e E. affinis. Estes resultados, juntamente com as observações de laboratório, sugerem que Z. intermedium é um epibionte obrigatório.

Growth of the peritrich epibiont Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia) estimated from laboratory experiments / Crescimento do peritríquio epibionte Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia) obtido através de experimentos em laboratório

Peritrich ciliates are commonly found colonizing living substrates. Although this a well known phenomenon, biological aspects of this relationship need to be studied in more detail. Assessment of growth rates in peritrichs has been the subject of very few studies. Only species in the genera Carchesium Ehrenberg, 1830 and Vorticella Linnaeus, 1767 had their growth rates evaluated in the field and in the laboratory. In the present study, growth, colonization (colonies/host), and proliferation (zooids/colony) rates of the peritrich epibiont Zoothamnium intermedium Precht, 1935 attached to the calanoid copepod Acartia tonsa Dana 1848 were evaluated in the laboratory in two food regimes: bacteria only, and algal based diet. Results showed that growth, colonization, and proliferation rates were similar for both diets. Maximum growth rates obtained for Z. intermedium was 0.85 and 0.83 per day, for bacteria and algae respectively. Maximum colonization rates were 0.5 per day for both diets, and the maximum proliferation rates were 0.44 and 0.42 per day for bacteria and algae respectively. These results demonstrate that Z. intermedium is able to grow at the same rate of other peritrichs on bacterial and algal based diets.

Ciliados peritríquios são geralmente encontrados colonizando a superfície de outros organismos. Embora este fenômeno seja bem documentado, certos aspectos biológicos desta associação ainda precisam ser estudados. Taxas de crescimento em peritríquios foram objeto de pouquíssimos estudos, visto que apenas espécies nos gêneros Carchesium e Vorticella tiveram suas taxas de crescimento calculadas em experimentos de campo e de laboratório. No presente trabalho, taxas de crescimento, colonização (colônias/hospedeiro) e proliferação (zooides/colônia) do peritríquio epibionte Zoothamnium intermedium colonizando o copépodo calanoide Acartia tonsa foram avaliadas em laboratório com duas dietas: bactéria somente e alga. Resultados demonstraram que taxas de crescimento, colonização e proliferação foram semelhantes para as duas dietas. A taxa de crescimento máxima observada para Z. intermedium foi de 0.85 e 0.83 por dia para bactéria e alga, respectivamente. A taxa máxima de colonização foi 0.5 por dia para as duas dietas e a taxa máxima de proliferação foi de 0.44 e 0.42 por dia para bactéria e alga, respectivamente. Estes resultados demonstram que Z. intermedium cresce em taxas semelhantes a outras espécies de peritríquios em dietas de bactérias ou de algas.

Experimental infection in Notodiaptomus sp. (Crustacea: Calanoida) with larvae of Camallanus sp. (Nematoda: Camallanidae)

This trial registered the experimental infection viability with nematode larvae Camallanus sp. in Notodiaptomus sp., a crustacean, which can be an intermediate host. Adult females of nematode were dissected from the intestines of Xiphophorus maculatus (Osteichthyes: Poeciliidae), at a fish farm in the State of São Paulo. Females were slightly compressed for larvae release, collected with Pasteur pipette and separated on Petri dishes with 9ml filtered water at 28.1°C, from zooplankton culture. Treatments consisted of Petri dishes with 60 and 105 copepods, in which 120, 150 and 210 larvae of nematode were added in four replications. Twenty-four and 36h after exposition to the larvae, the copepods were fixed in 70 percent alcohol to record the amount of fixed larvae. Twenty four hours after exposition, 60 copepods group with 120 larvae showed significantly higher prevalence (46.5 percent) when compared to 105 copepods and 120 larvae (33.2 percent). Thus, these answers suggested that 120 larvae were enough for a successful infectivity. Experimental infection was available and so, it was used as a pattern to life cycle studies of camallanid nematodes and hosts susceptibility tests.

A viabilidade da infecção experimental com larvas do nematóide Camallanus sp. em Notodiaptomus sp., crustáceo com potencial para hospedeiro intermediário foi avaliada. Fêmeas adultas do nematóide foram extraídas de Xiphophorus maculatus (Osteichthyes: Poeciliidae), provenientes de piscicultura de peixes ornamentais no estado de São Paulo. As fêmeas foram ligeiramente pressionadas para liberar as larvas, coletadas com pipeta Pasteur e separadas em placas de Petri contendo 9ml de água filtrada a 28,1°C do próprio cultivo de zooplâncton. Os tratamentos consistiram de placas contendo 60 e 105 copépodes onde se adicionou 120, 150 e 210 larvas de nematóides em quatro repetições. Nos tempos de 24 e 36h após a exposição às larvas, os copépodes foram fixados em álcool 70 por cento para quantificação de larvas. Após 24h de exposição, o grupo com 60 copépodes na presença de 120 larvas apresentou maior prevalência (46,5 por cento) do que 105 copépodes com 120 larvas (33,2 por cento). Sugere-se que 120 larvas foram suficientes para o sucesso da infecção. A infecção experimental mostrou-se viável, servindo de modelo para o estudo do ciclo de vida de camalanídeos e testes de susceptibilidade de hospedeiros.

Sticholonche zanclea (Protozoa, Actinopoda) in fecal pellets of copepods and Euphausia sp. in Brazilian coastal waters / Sticholonche zanclea (Protozoa, Actinopoda) em pelotas fecais de copépodos e Euphasia sp. em águas costeiras brasileiras

Fecal pellets produced by mesozooplanktonic copepods (Centropages velificatus and Paracalanus parvus) and macrozooplanktonic Euphausiacea (Euphausia sp.) were examined using scanning electron microscopy. Fragments of the protozoan Sticholonche zanclea were found in both copepod and in Euphausia sp. fecal pellets, even when the abundance of the protozoan in the water was low. The results suggest that S. zanclea is an important food resource for different trophic levels, including meso- and macrozooplankton, in Brazilian coastal waters.

Pelotas fecais produzidas por copépodos mesozooplanctônicos (Centropages velificatus e Paracalanus parvus) e por Euphasiacea macrozooplanctônico (Euphasia sp) foram examinadas em microscópio eletrônico de varredura. Fragmentos do protozoário Sticholonche zanclea foram encontrados nas pelotas fecais dos copépodos e de Euphasia sp, mesmo quando a abundância do protozoário no ambiente foi bastante reduzida. Os resultados sugerem que S. zanclea pode representar um importante recurso alimentar para diferentes níveis tróficos, incluindo meso e macrozooplâncton, em águas costeiras brasileiras.

Gnathostoma infection in Nakhon Nayok and Prachin Buri, Central Thailand.

Gnathostoma infection in Nakhon Nayok and Prachin Buri Provinces, Central Thailand, was investigated. The prevalence and intensity of infection of swamp eels were determined; dog fecal samples and fresh-water copepods were examined for evidence of infection. The overall prevalence of eel infection was 38.1% (117/307) in Nakhon Nayok and 24.0% (74/308) in Prachin Buri--the former rate being significantly higher than the latter. Most of the positive Nalkhon Nayok eels (53.8%) harbored only 1-9 larvae; only one eel bore more than 50 larvae. In Prachin Buri, 67.6% of the positive eels harbored 1-9 larvae; again, only one eel bore more than 50 larvae. The mean number of 11.0 +/- 10.4 larvae/eel in Nakhon Nayok was not significantly different from that of Prachin Buri (9.3 +/- 11.4). A total of 1,292 gnathostome larvae were recovered from 307 eels in Nakhon Nayok. Of these, 52.3% had accumulated in the liver and 47.7% had spread throughout the muscles. In eels from Prachin Buri, 50.6% and 49.4% of the total of 688 larvae (from 308 eels) were found in the liver and muscles, respectively. The larvae preferred encysting in ventral of muscles rather than dorsal part; they preferred the middle portion to the anterior and posterior portions. The average length of gnathostome larvae recovered from Nakhon Nayok eels was 4.0 +/- 0.5 mm (range 2.5-5.1 mm) and the average body width was 0.40 +/- 0.05 mm (range 0.29-0.51 mm). Those from eels in Prachin Buri were 3.9 +/- 0.5 mm (range 2.2-5.1 mm) and 0.34 +/- 0.05 mm (range 0.20-0.48 mm), respectively. The mean body length and width of the larvae from eels in Nakhon Nayok were significantly greater than those of the larvae from eels in Prachin Buri. In Ban Phrao, Nakhon Nayok, none of the first 44 fecal specimens examined was positive. Of the second (68) and the third (70) specimens, one (1.5%) and two (2.9%) samples were positive. However, six months after the third fecal collection, no eggs were found. In Tha Ngam, Prachin Buri, no eggs were found in all three batches (109, 115, and 100 fecal samples). A cyclops survey of 4,000-5,000 crustacea from each of two areas (Ban Phrao and Tha Ngam) found no evidence of natural cyclops infection.

Aspectos anátomo-patológicos da parasitose por Lernaea cyprinacea (L) (Crustacea: Copepoda) em tambaqui (Colossoma macropomum Cuvier, 1818) / Anatomo-pathological aspects of the parasitism caused by Lernaea cyprinacea (L) (Crustacea: Copepoda) in the "tambaqui" (Colossoma macropomum Cuvier, 1818)

Uma amostragem de trinta tambaquis (Colossoma macropomum Cuvier, 1818), com idade e peso variados, foi examinada para a detecção de parasitismo por Lernaea cyprínacea; sete deles apresentam o ectoparasita. Os peixes com lerneose possuíam idade entre quatro meses e um ano, com peso máximo de 1 kg. Vinte peixes adultos com idade acima de quatro anos, não mostraram a presença de L. cyprínacea. O número máximo de copépodes encontrados por hospedeiro foi três. As nadadeiras e suas bases de inserção no corpo foram o local mais comum de fixação nos peixes pesquisados. A lesão provocada por L. cyprínacea se apresentou, macroscopicamente, como uma hemorragia discreta e limitada ao ponto de inserção do copépode. A análise histopatológica demonstrou infiltração leococitária mononuclear e neovascularização com intensa hemorragia nos tecidos ao redor da estrutura de fixação do parasita. Em um exemplar, a reação inflamatória foi seguida de ulceração e pelo início de um processo de fibrose no local de penetração do parasita.

A sample of thirty specimens of the "tambaqui" (Colossoma macropomum Cuvier, 1818), was collected in the fish pond of the Agricultural College ldelfonso Bastos Borges at Bom Jesus de ltabapoana, State of Rio de Janeiro. They had varied ages and weights and were examined to detect the ectoparasite L. cyprinacea. Seven of them presented lerneosis and had from four months to one year with a maximum of 1 kg. Twenty adults specimens with more than four years did not present the parasitis. The maximum number of copepods per host was three and these parasites were usually fixed in the fins and in their attachment bases in the fish body. Macroscopically, the injury caused by L. cyprinacea showed a discrete and localized hermorrhage at the attachment area. The histopathological analysis exhibited a mononuclear leococitic infiltration and neovascularization with hemorrhage around the tissues of the appendages of the parasite. In some cases, the inflamatory reaction involved them, trying to isolate copepod from the tissue of the host. In one specimen, it was observed that the inflamatory reaction was followed by ulceration and by a fibrous process in the penetrating area of the parasite.