Observations on Eimeria species of Dasyprocta leporina (Linnaeus, 1758)(Rodentia: Dasyproctidae) from the state of Pará, North Brazil

Redescriptions are given of the mature oocysts of Eimeria aguti Carini 1935, E. cotiae Carini, 1935 and E. paraensis Carini, 1935, in the faeces of five specimens of the rodent Dasyprocta leporina (Rodentia: Dasyproctidae) from the state of Pará, North Brazil. New information is provided on the sporulation time of these parasites and the prepatent period in experimentally infected D. leporina. Some endogenous stages of E. cotiae are described in the epithelial cells of the ileum, and the absence of any oocysts in the gall-bladder contents of the infected animals indicates that the intestine is also the site of development of E. aguti and E. paraensis. Difficulties in separating E. cotiae and E. paraensis on morphology of the oocysts are discussed. The oocysts of both parasites share many structural features and have a wide size range. It is concluded that although it is at present best to maintain these names, the possibility exists that they were separately given to oocysts of smaller dimensions (E. cotiae) and larger dimensions (E. paraensis) of a single parasite. Location of an endogenous site of development for E. paraensis that is distinctly separate from that of E. cotiae might establish more definitely the separate specific status of the two parasites.

Capillostrongyloides arapaimae sp. n. (Nematoda: Capillariidae), a new intestinal parasite of the arapaima Arapaima gigas from the Brazilian Amazon

A new nematode species, Capillostrongyloides arapaimae sp. n., is described from the intestine and pyloric caeca of the arapaima, Arapaima gigas (Schinz), from the Mexiana Island, Amazon river delta, Brazil. It is characterized mainly by the length of the spicule (779-1,800 µm), the large size of the body (males and gravid females 9.39-21.25 and 13.54-27.70 mm long, respectively) and by the markedly broad caudal lateral lobes in the male. It is the third species of genus Capillostrongyloides reported to parasitize Neotropical freshwater fishes.

Antibacterial and cytotoxic activity of Kenyan medicinal plants

Seven medicinal plant extracts traditionally used in Kenya, mainly for management of infectious conditions, were chosen and screened for their antibacterial activity against Gram-negative (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive (Bacillus cereus and Staphylococcus aureus) bacteria. Antibacterial activity was tested using the broth dilution method. Harrisonia abyssinica and Terminalia kilimandscharica extracts showed significant activity against Gram+ and Gram- bacteria. The methanolic extracts of T. kilimandscharica bark and H. abyssinica bark and leaves showed minimum inhibitory activity against all tested bacteria, with minimal inhibitory concentrations ranging from 25-150 mg/mL. Ajuga remota and Amaranthus hybridus, which are lethal to brine shrimp nauplii, showed significantly lower antibacterial activity than those that were relatively non-toxic.

Biological activity of neosergeolide and isobrucein B (and two semi-synthetic derivatives) isolated from the Amazonian medicinal plant Picrolemma sprucei (Simaroubaceae)

In the present study, in vitro techniques were used to investigate a range of biological activities of known natural quassinoids isobrucein B (1) and neosergeolide (2), known semi-synthetic derivative 1,12-diacetylisobrucein B (3), and a new semi-synthetic derivative, 12-acetylneosergeolide (4). These compounds were evaluated for general toxicity toward the brine shrimp species Artemia franciscana, cytotoxicity toward human tumour cells, larvicidal activity toward the dengue fever mosquito vector Aedes aegypti, haemolytic activity in mouse erythrocytes and antimalarial activity against the human malaria parasite Plasmodium falciparum. Compounds 1 and 2 exhibited the greatest cytotoxicity against all the tumor cells tested (IC50 = 5-27 µg/L) and against multidrug-resistant P. falciparum K1 strain (IC50 = 1.0-4.0 g/L) and 3 was only cytotoxic toward the leukaemia HL-60 strain (IC50 = 11.8 µg/L). Quassinoids 1 and 2 (LC50 = 3.2-4.4 mg/L) displayed greater lethality than derivative 4 (LC50 = 75.0 mg/L) toward A. aegypti larvae, while derivative 3 was inactive. These results suggest a novel application for these natural quassinoids as larvicides. The toxicity toward A. franciscana could be correlated with the activity in several biological models, a finding that is in agreement with the literature. Importantly, none of the studied compounds exhibited in vitro haemolytic activity, suggesting specificity of the observed cytotoxic effects. This study reveals the biological potential of quassinoids 1 and 2 and to a lesser extent their semi-synthetic derivatives for their in vitro antimalarial and cytotoxic activities.

Camallanus tridentatus (Drasche) (Nematoda: Camallanidae): new taxonomically important morphological data

Camallanus tridentatus is redescribed on the basis of the examination of specimens obtained from the stomach, caeca and intestine of the naturally infected arapaima Arapaima gigas (Schinz) from the Mexiana Island, Amazon River Delta, Brazil. Data on the surface morphology of adults inferred from confocal laser scanning and scanning electron microscopical observations are also provided. The study revealed some taxonomically important, previously unreported morphological features in this species, such as the presence of the poorly sclerotized left spicule and deirids. C. tridentatus distinctly differs from other congeneric species parasitizing freshwater fishes in South America mainly in the structure of the buccal capsule and the female caudal end. C. maculatus Martins, Garcia, Piazza and Ghiraldelli is considered a junior synonymm of Camallanus cotti Fujita.

In vitro antiplasmodial activity and toxicity assessment of plant extracts used in traditional malaria therapy in the Lake Victoria Region

As part of our program screening the flora of the Lake Victoria Region, a total of 54 organic extracts from seven plant families (8 species) were individually tested for antiplasmodial activity against chloroquine-sensitive [Sierra Leone (D-6)] and chloroquine-resistant [Vietnam (W-2)] strains. Only 22% of these extracts exhibited very high in vitro antiplasmodial activity. Six methanol (MeOH) extracts and one chloroform extract showed in vitro antiplasmodial activity against the D-6 Plasmodium falciparum strain, while only three MeOH extracts were active against the W-2 strain. All of the ethyl acetate extracts proved to be inactive against both strains of P. falciparum. A brine shrimp cytotoxicity assay was used to predict the potential toxicity of the extracts. The cytotoxicity to antiplasmodial ratios for the MeOH extracts were found to be greater than 100, which could indicate that the extracts are of low toxicity.

Faecal examination and PCR to detect Strongyloides venezuelensis in experimentally infected Lewis rats

More sensitive methodologies are necessary to improve strongyloidiasis diagnosis. This study compared the sensitivities of the McMaster modified technique and polymerase chain reaction (PCR) assays, both performed in faecal samples. Lewis rats were subcutaneously infected with 4,000, 400 or 40 infective third-stage larvae, considered as high, moderate or low infection, respectively. Seven days later, they were euthanized to count adult nematodes recovered from the small intestine. Stool samples were used to count the number of eggs per gram (EPG) of faeces and to detect parasite DNA by PCR performed with a species and a genus primer pair. The sensitivity of these assays depended upon parasite burden and the primer specificity. All assays presented 100% sensitivity at the highest parasite load. In the moderate infection, EPG and PCR with the genus primer maintained 100% specificity, whereas PCR sensitivity with the species primer decreased to 77.7%. In low infection, the sensitivity was 60% for EPG, 0% for PCR with the species primer and 90% for PCR done with the genus primer. Together, these results suggest that PCR with a genus primer can be a very sensitive methodology to detect Strongyloides venezuelensisin faeces of Lewis rats infected with very low parasite burden.

In vitro and in vivo effects of Enterococcus faecalis CECT7121 on Toxocara canis

The aim of the present paper was to evaluate the larvicidal effect of Enterococcus faecalis CECT7121 (Ef7121) on the Toxocara canis cycle both in vitro and in vivo. For the in vitro experiments, T. canis larvae were incubated with the supernatants of Ef7121 (EI) and mutant Ef7121 (EIm), in a pre-culture of Ef7121 (EII) and in a fresh culture with Ef7121 (EIII) and the Ef7121 mutant strain (EIIIm). The viability of the larvae was calculated after a 48 h incubation. A significant reduction of the viability of T. canis larvae was observed in EI, EII and EIII. A decrease of this inhibitory effect was observed in EIm and EIIIm (p = 0.008). In the in vivo experiments, mice were orally inoculated with three doses of Ef7121. To study the probiotic persistence in the intestine, the animals were sacrificed every four days and their intestines were dissected. The initial average bacterial levels were 9.7 x 10(4) for Ef7121 (colony forming units/g). At the end of the assay the levels were 1.46 x 10(4). No bacterial translocation was detected in mesenteric lymphatic nodules and spleen. Ef7121 interference with the biological cycle was evaluated in mice challenged with T. canis. The interference was significant when the mice were challenged with probiotic and T. canis simultaneously (p = 0.001), but it was not significant when the challenge was performed 15 days after administration of the bacterial inoculum (p = 0.06). In conclusion, Ef7121 possessed in vitro and in vivo larvicidal activity.

Biomphalaria alexandrina snails as immunogens against Schistosoma mansoni infection in mice

Despite effective chemotherapy, schistosomiasis remains the second largest public health problem in the developing world. Currently, vaccination is the new strategy for schistosomiasis control. The presence of common antigenic fractions between Schistosoma mansoni and its intermediate host provides a source for the preparation of a proper vaccine. The objective of this paper is to evaluate the nucleoprotein extracted from either susceptible or resistant snails to protect against schistosomiasis. The vaccination schedule consisted of a subcutaneous injection of 50 µg protein of each antigen followed by another inoculation 15 days later. Analyses of marker enzymes for different cell organelles [succinate dehydrogenase, lactate dehydrogenase (LDH), glucose-6-phosphatase, acid phosphatase and 5'-nucleotidase] were carried out. Energetic parameters (ATP, ADP, AMP, phosphate potentials, inorganic phosphate, amino acids and LDH isoenzymes) were also investigated. The work was extended to record worm and ova counts, oogram determination in the liver and intestine and the histopathological pattern of the liver. The nucleoprotein of susceptible snails showed reduction in worm and ova counts by 70.96% and 51.31%, respectively, whereas the nucleoprotein of resistant snails showed reductions of 9.67% and 16.77%, respectively. In conclusion, we found that the nucleoprotein of susceptible snails was more effective in protecting against schistosomiasis.

Raphidascaris (Sprentascaris) lanfrediae sp. nov. (Nematoda: Anisakidae) from the fish Satanoperca jurupari (Osteichthyes: Cichlidae)

Raphidascaris (Sprentascaris) lanfrediae sp. nov. is described from the intestine of the freshwater fish Satanoperca jurupari (Heckel) (Cichlidae) from the Guamá River, state of Pará, Brazil. The prevalence in fish (n = 59) was 27% with intensity of one-124 (mean 16) nematodes per fish. The new species is characterized mainly by the markedly larger size of ventricular appendix in relation to the oesophagus, presence of short male caudal alae, 14-16 subventral pairs of preanal papillae and six pairs of postanal papillae.

A new species of Mesocoelium (Digenea: Mesocoeliidae) found in Rhinella marina (Amphibia: Bufonidae) from Brazilian Amazonia

Mesocoelium lanfrediae sp. nov. (Digenea: Mesocoeliidae) inhabits the small intestine of Rhinella marina (Amphibia: Bufonidae) and is described here, with illustrations provided by light, scanning electron microscopy and molecular approachs. M. lanfrediae sp. nov. presents the typical characteristics of the genus, but is morphometrically and morphologically different from the species described previously. The main diagnostic characteristics of M. lanfrediae sp. nov. are (i) seven pairs of regularly-distributed spherical papillae on the oral sucker, (ii) ventral sucker outlined by four pairs of papillae distributed in a uniform pattern and interspersed with numerous spines, which are larger at the posterior margin and (iii) small, rounded tegumentary papillae around the opening of the oral sucker, which are morphologically different from those of the oral sucker itself, some of which are randomly disposed in the ventrolateral tegumentary region of the anterior third of the body. Addionally, based on SSU rDNA, a phylogenetic analysis including Brachycoeliidae and Mesocoeliidae taxa available on GenBank established the close relationship between M. lanfrediae sp. nov. and Mesocoelium sp.

Oxygen consumption of Litopenaeus vannamei juveniles in heterotrophic medium with zero water exchange

This work aimed at determining the dissolved oxygen consumption rate of Litopenaeus vannamei juveniles maintained in a microbial biofloc raceway system at high density with no aeration. Three 4 L bottles were filled for each treatment, sealed hermetically, and placed in an enclosed greenhouse raceway system. Four shrimp (13.2±1.42 g) were assigned to two sets of the bottles, which underwent the following treatments: light conditions with no shrimp; dark conditions with no shrimp; light conditions with shrimp; and dark conditions with shrimp. Dissolved oxygen content was measured every 10 min for 30 min. A quadratic behavior was observed in dissolved oxygen concentration over time. Significant differences for oxigen consumption were observed only at 10 and 20 min between shrimp maintained in the dark and those under light conditions. At 10 min, a higher value was observed in shrimp maintained under light, and at 20 min, in the dark. Significant differences between 10 and 20 min and between 10 and 30 min were observed when oxygen consumption was analyzed over time in the presence of light. Under dark conditions there were significant differences only between 20 and 30 min. Lethal oxygen concentration (0.65 mg L-1) would be reached in less than one hour either under light or dark conditions with no aeration.

Estudo fitoquímico de Unonopsis lindmanii - Annonaceae, biomonitorado pelo ensaio de toxicidade sobre a Artemia salina leach

Extracts obtained from leaves, seeds and bark of Unonopsis lindmanii were evaluated by means of Brine Shrimp Lethality test (BSL). Through bioassay-guided chromatographic fractionation, liriodenine, an oxoaporphine alkaloid, was isolated from the bark extracts as the bioactive compound. Two additional inactive known alkaloids, unonopsine and lysicamine were also isolated from the bark extracts.

Síntese de 1,3,5-triazinas substituídas e avaliação da toxicidade frente a Artemia Salina leach

The synthesis of ten symmetrically and unsymmetrically substituted 1,3,5-triazines by Phase Transfer Catalysis (PTC) method is described. Their toxicities were determined against Artemia salina Leach. The LD50 values have also been obtained for these compounds.

Estudo fitoquímico das cascas do caule de Duguetia glabriuscula - Annonaceae, biomonitorado pelo ensaio de toxicidade frente a Artemia salina leach

The extract obtained from stem bark of Duguetia glabriuscula - Annonaceae was evaluated by Brine Shrimp Lethality test (BSL). The bioactive compounds, oxobufoline and lanuginosine, two oxoaporphine alkaloids were isolated by activity-guided fractionation. In addition, the compounds asaraldehyde, (+)-allo-aromadendrane-10beta, 14-diol, and two aporphine alkaloids, polyalthine and oliveridine were also obtained.