Responses of antioxidant enzymes, photosynthetic pigments and carbohydrates in micropropagated Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) under ex vitro water deficit and after rehydration / Respostas de enzimas antioxidantes, pigmentos fotossintéticos e carboidratos em Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) micropropagadas, sob déficit hídrico ex vitro e após reidratação

In this study, the activities of antioxidant enzymes, photosynthetic pigments, proline and carbohydrate contents in Pitcairnia encholirioides under ex vitro conditions of water deficit were evaluated. Results show that plants under progressive water stress, previously in vitro cultured in media supplemented with 30 g L-1 sucrose and GA3, accumulated more proline and increased peroxidase (POD) activity and the contents of photosynthetic pigments and carbohydrates. For plants previously in vitro cultured with 15 g L-1 sucrose and NAA, no differences were found for proline content and there were reductions in activities of peroxidase (POD), catalase (CAT) and poliphenoloxidase (PPO), and in contents of carbohydrates, with progress of ex vitro water deficit. After rehydration, plants showed physiological recovery, with enzymatic activities and contents of metabolites similar to those found in the controls not submitted to dehydration, regardless of the previous in vitro culture conditions. These results show that micropropagated P. encholirioides has high tolerance to dehydration once in ex vitro conditions, which can ensure the survival of plants from tissue culture when transferred to its natural environment, emphasizing the importance of such biotechnology for the propagation of endangered species.

Neste estudo, foram avaliadas as atividades de enzimas antioxidantes, pigmentos fotossintéticos, conteúdo de prolina e carboidratos em Pitcairnia encholirioides sob déficit hídrico em condições ex vitro. Os resultados mostraram que as plantas sob estresse hídrico progressivo, previamente cultivadas in vitro em meio de cultura suplementado com 30 g L-1 de sacarose e GA3 acumularam mais prolina e aumentaram a atividade da peroxidase (POD) e os teores de pigmentos fotossintéticos e carboidratos. Para plantas previamente cultivadas in vitro com 15 g L-1 de sacarose e ANA, não foram encontradas diferenças nos conteúdos de prolina e houve reduções nas atividades da peroxidase (POD), catalase (CAT) e polifenoloxidase (PPO), e no conteúdo de carboidratos, com o progresso do déficit hídrico ex vitro. Após a reidratação, as plantas apresentaram recuperação fisiológica, com atividades enzimáticas e conteúdo de metabólitos semelhantes aos encontrados nos controles não sujeitos à desidratação, independentemente das condições de cultivo in vitro. Estes resultados mostram que P. encholirioides micropropagada tem alta tolerância à desidratação uma vez em condições ex vitro, o que pode garantir a sobrevivência de plantas provenientes da cultura de tecidos quando transferidas para seu ambiente natural, enfatizando a importância desta biotecnologia para a propagação de espécies ameaçadas.

Responses of antioxidant enzymes, photosynthetic pigments and carbohydrates in micropropagated Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) under ex vitro water deficit and after rehydration / Respostas de enzimas antioxidantes, pigmentos fotossintéticos e carboidratos em Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) micropropagadas, sob déficit hídrico ex vitro e após reidratação

Abstract In this study, the activities of antioxidant enzymes, photosynthetic pigments, proline and carbohydrate contents in Pitcairnia encholirioides under ex vitro conditions of water deficit were evaluated. Results show that plants under progressive water stress, previously in vitro cultured in media supplemented with 30 g L-1 sucrose and GA3, accumulated more proline and increased peroxidase (POD) activity and the contents of photosynthetic pigments and carbohydrates. For plants previously in vitro cultured with 15 g L-1 sucrose and NAA, no differences were found for proline content and there were reductions in activities of peroxidase (POD), catalase (CAT) and poliphenoloxidase (PPO), and in contents of carbohydrates, with progress of ex vitro water deficit. After rehydration, plants showed physiological recovery, with enzymatic activities and contents of metabolites similar to those found in the controls not submitted to dehydration, regardless of the previous in vitro culture conditions. These results show that micropropagated P. encholirioides has high tolerance to dehydration once in ex vitro conditions, which can ensure the survival of plants from tissue culture when transferred to its natural environment, emphasizing the importance of such biotechnology for the propagation of endangered species.

Resumo Neste estudo, foram avaliadas as atividades de enzimas antioxidantes, pigmentos fotossintéticos, conteúdo de prolina e carboidratos em Pitcairnia encholirioides sob déficit hídrico em condições ex vitro. Os resultados mostraram que as plantas sob estresse hídrico progressivo, previamente cultivadas in vitro em meio de cultura suplementado com 30 g L-1 de sacarose e GA3 acumularam mais prolina e aumentaram a atividade da peroxidase (POD) e os teores de pigmentos fotossintéticos e carboidratos. Para plantas previamente cultivadas in vitro com 15 g L-1 de sacarose e ANA, não foram encontradas diferenças nos conteúdos de prolina e houve reduções nas atividades da peroxidase (POD), catalase (CAT) e polifenoloxidase (PPO), e no conteúdo de carboidratos, com o progresso do déficit hídrico ex vitro. Após a reidratação, as plantas apresentaram recuperação fisiológica, com atividades enzimáticas e conteúdo de metabólitos semelhantes aos encontrados nos controles não sujeitos à desidratação, independentemente das condições de cultivo in vitro. Estes resultados mostram que P. encholirioides micropropagada tem alta tolerância à desidratação uma vez em condições ex vitro, o que pode garantir a sobrevivência de plantas provenientes da cultura de tecidos quando transferidas para seu ambiente natural, enfatizando a importância desta biotecnologia para a propagação de espécies ameaçadas.

Involvement of mast cells, CD68+ and VEGF+ expressions in response to Himatanthus drasticus commercial latex in mice wound healing model / Envolvimento de mastócitos, expressão de CD68+ e VEGF+ em resposta ao látex comercial de Himatanthus drasticus em modelo de cicatrização em camundongos

This study aimed to evaluate Himatanthus drasticus latex in a mice wound healing experimental model. Animals were divided into four groups (n=7) according to the treatments: GI - saline 0.9% (control), GII - mineral oil (vehicle), GIII - H. drasticus commercial latex (HdCL) and GIV - H. drasticus mixed isolated fraction (MIF, 1 mg/mL). The treatments were applied topically once daily, 50 µL for 14 consecutive days. Macroscopic lesions were evaluated, considering parameters such as swelling, redness, granulation tissue and reepithelialization. VEGF+, CD68+ expressions and mast cells (Toluidin blue stain) were evaluated. HdCL induced higher contraction and exuberant granulation tissue (P > 0.05). HdCL showed a mild inflammatory process while MIF induced intense infiltrate inflammatory predominantly by lymphocytes, vascular congestion, bleeding and did not presented full reepithelialization. Reorganization of collagen fibers (red picrosirius stain) was observed. CD68+ expression and mast cells were presented as moderate, intense and mild in GI, GIII and GIV, respectively. Neovascularization occurred in all groups, while VEGF+ expression was intense in MIF in relation to HdCL. We concluded that HdCL presents wound healing potential, through modulation of mast cells, CD68+ and VEGF+ expressions that can be associated to triterpenes presence according MIF isolated from HdCL.(AU)

Objetivou-se avaliar o látex de Himatanthus drasticus em feridas induzidas experimentalmente em camundongos. Os animais foram divididos em quatro grupos (n=7): GI - salina 0,9% (controle), GII - óleo mineral (veículo), GIII - látex comercial de H. drasticus (HdCL) e GIV - fração isolada mista de H. drasticus (MIF, 1mg/mL). Os tratamentos foram aplicados topicamente uma vez ao dia (50µL), durante 14 dias consecutivos. Lesões macroscópicas, as expressões de VEGF+, CD68+ e a participação dos mastócitos (coloração azul de toluidina) foram avaliadas. HdCL induziu maior contração e tecido de granulação exuberante (P >0,05). HdCL induziu leve processo inflamatório enquanto MIF promoveu intenso infiltrado inflamatório predominantemente linfocítico, congestão vascular, hemorragia e reepitelização parcial. Observou-se reorganização das fibras colágenas (coloração picrosírius). A expressão de CD68+ e os mastócitos apresentaram-se moderados, intensos e leves em GI, GIII e GIV, respectivamente. A neovascularização foi observada em todos os grupos, enquanto a expressão de VEGF+ foi mais intensa em MIF em relação a HdCL. Conclui-se que HdCL apresenta potencial de cicatrização por meio da modulação dos mastócitos e das expressões de CD68+ e VEGF+, o que pode estar associado à presença de triterpenos de acordo com MIF isolada de HdCL.(AU)

Transferência passiva de soro hiperimune anti-Streptococcus agalactiae e seu efeito profilático em tilápias-do-nilo infectadas experimentalmente: sobrevivência e títulos de anticorpos / Passive transfer of hyperimmune serum anti Streptococcus agalactiae and its prophylactic effect on Nile tilapia experimentally infected

A bactéria Streptococcus agalactiae é um potente agente causador de surtos por doenças bacterianas em peixes. O estresse provocado pelo manejo zootécnico e pela má qualidade ambiental torna a tilápia susceptível às infecções por essa bactéria. O objetivo do presente trabalho foi avaliar a resistência de tilápias-do-nilo imunizadas com soro hiperimune anti-S. agalactiae, posteriormente desafiadas com cepa homóloga da mesma bactéria. Após determinação da DL 50 de S. agalactiae, 36 tilápias foram distribuídas em quatro aquários, dois para o grupo controle e dois para inoculação celomática para produção de anticorpos anti-S. agalactiae. No 21° e 28° dias, foi coletado sangue para obtenção de soro hiperimune utilizado na transferência passiva. Em seguida, 30 tilápias foram distribuídas em três aquários e submetidas a três tratamentos: GI: controle; GII: imunizadas com o soro inativado; GIII: imunizadas com soro ativo...

The Streptococcus agalactiae bacteria is a potent agent which causes outbreaks of bacterial diseases in fish. The stress caused by management and poor environmental quality makes tilapia susceptible to infections, including by bacterium. The aim of this study was to evaluate the resistance of the Nile tilapia immunized with hyperimmune serum against S. agalactiae subsequently challenged with homologous strain of the same bacteria. After determining the DL 50 of S. agalactiae, 36 tilapias were distributed in 4 aquariums, 2 for the control group and 2 for the group via coelomic, inoculated with the DL 50 for anti-S. agalactiae antibodies production. On the 21st and 28th day blood was collected for the obtainment of hiperimmune serum used in passive transference. Then, 30 tilapias were distributed in 3 aquariums submitted to 3 treatments (GI: control; GII: immunized with inactivated-serum; GIII: immunized with non-inactivated serum)...

Prevalência de anticorpos contra Leptospira spp. em bovinos, caninos, equinos, ovinos e suínos do município de Jaguapitã, estado do Paraná, Brasil / Prevalence of antibodies against Leptospira spp. in cattle, dogs, horses, sheep and swine of Jaguapitã, state of Paraná, Brazil

O objetivo deste trabalho foi determinar a prevalência de anticorpos contra Leptospira spp. em bovinos, caninos, equinos, ovinos e suínos, oriundos de 40 propriedades localizadas na área rural do Município de Jaguapitã, Estado do Paraná. Foram colhidas amostras de sangue de 370 bovinos, 161 equinos, 70 ovinos, 230 suínos e 97 caninos. O número de animais testados em cada propriedade, assim como o número de propriedades, foi determinado utilizando-se o programa Epi-info versão 6. As amostras de soros obtidas foram submetidas à prova de soroaglutinação microscópica (SAM) com 22 sorovares de Leptospira spp. Das 40 propriedades rurais pesquisadas, 38 (95,00%) tiveram pelo menos um animal sororeagente na SAM e dos 928 animais estudados, 316 (34,08%) apresentaram títulos ? 100. A prevalência observada na espécie bovina foi de 42,43%, com 87,18% das propriedades apresentando pelo menos um animal sororeagente. As prevalências de animais e propriedades reagentes para as demais espécies foram, respectivamente, 48,44% e 87,18% para equinos; 38,57% e 100% para ovinos; 18,70% e 28,00% para suínos; 11,34% e 31,25% para cães. O sorovar mais provável encontrado em bovinos foi Hardjo, em equinos Castellonis e Sentot, em ovinos, suínos e cães Icterohaemorrhagiae. Os resultados obtidos neste trabalho demonstram que as cinco espécies animais estudadas na área rural do Município de Jaguapitã tiveram contato com vários sorovares de Leptospira spp. Além disso, os resultados sorológicos sugerem uma possível transmissão do micro-organismo entre espécies animais, provavelmente em decorrência da exposição às mesmas fontes de infecção entre os animais estudados.

The objective of this work was to determine the prevalence of antibodies against Leptospira spp. in cattle, dogs, horses, sheep and swine from 40 properties located in the rural area of Jaguapitã, state of Paraná, Brazil. Blood samples were taken from 370 cattle, 97 dogs, 161 horses, 70 sheep and 230 swine. The number of animals tested on each property, as well as the number of properties was determined using the program Epi-info version 6. Samples of serum were submitted to microscopic agglutination test (MAT) with 22 Leptospira spp. serovars. From the 40 rural properties investigated, 38 (95.00%) had at least one positive animal according to SAM, and from 928 studied animals, 316 (34.08%) presented titers ? 100. The prevalence observed in the bovine species was 42.43%, with 87.18% of the properties presenting at least one positive animal. The prevalence of animals and properties reactive for the other species were, respectively: 48.44% and 87.18% for horses; 38.57% and 100% for sheep; 18.70% and 28.00% for swine; 11.34% and 31.25% for dogs. The most frequent serovar in bovines was Hardjo, in horses Castellonis and Sentot, in sheep, swine and dogs Icterohaemorrhagiae. The results obtained in this study demonstrated that the 5 studied animal species in the rural area of Jaguapitã had contact with several Leptospira spp. serovars. Moreover, serological results suggest a possible transmission of Leptospira spp. between animal species, probably because of exposure to the same sources of infection among the animals studied.

Situação epidemiológica da brucelose bovina no Estado do Paraná / Epidemiological situation of bovine brucellosis in the State of Paraná, Brazil

Realizou-se um estudo para caracterizar a situação epidemiológica da brucelose bovina no Estado do Paraná. O Estado foi estratificado em sete circuitos produtores ou regiões. Em cada circuito foram amostradas aleatoriamente cerca de 300 propriedades e, dentro dessas, foi escolhido de forma aleatória um número pré-estabelecido de animais, dos quais foi obtida uma amostra de sangue. No total, foram amostrados 14.857 animais, provenientes de 2.098 propriedades. Em cada propriedade amostrada foi aplicado um questionário epidemiológico para verificar o tipo de exploração e as práticas zootécnicas e sanitárias que poderiam estar associadas ao risco de infecção pela doença. O protocolo de testes utilizado foi o da triagem com o teste do antígeno acidificado tamponado e o reteste dos positivos com o teste do 2-mercaptoetanol. O rebanho foi considerado positivo se pelo menos um animal foi reagente às duas provas sorológicas. Para o Estado, os resultados de prevalências de focos e de animais infectados foram, respectivamente, de 4,0 por cento [3,2-4,8 por cento] e 1,7 por cento [1,1-2,4 por cento]. Para os circuitos, a prevalência de focos e a de animais foram, respectivamente: circuito 1, 14,7 por cento [10,9-19,2 por cento] e 2,8 por cento [1,2-4,4 por cento]; circuito 2, 8,8 por cento [5,9-12,6 por cento] e 2,4 por cento [1,0-3,8 por cento]; circuito 3, 3,4 por cento [1,6-6,1 por cento] e 0,85 por cento [0,21-1,5 por cento]; circuito 4, 2,3 por cento [0,94-4,8 por cento] e 0,83 por cento [0,02-1,6 por cento]; circuito 5, 2,3 por cento [0,94-4,7 por cento] e 1,6 por cento [0,06-3,3 por cento]; circuito 6, 0,3 por cento [0-1,9 por cento] e 0,09 por cento [0-0,27 por cento]; circuito 7, 1,0 por cento [0,21-2,9 por cento] e 2,2 por cento [0-6,0 por cento]. Os fatores de risco (odds ratio, OR) associados à condição de foco foram: compra de reprodutores (OR= 2,20 [1,42-3,40]) e prática de aluguel de pasto (OR= 2,45 [1,54-3,90]).

A study to characterize the epidemiological situation of bovine brucellosis in the State of Paraná was carried out. In this study, the State was divided into seven regions. Three hundred herds were randomly sampled in each region and a pre-established number of animals were sampled in each of these herds. A total of 1,4857 serum samples from 2,098 herds were collected. In each herd, it was applied an epidemiological questionnaire regarding herd features and also husbandry and sanitary practices that could be associated with risk of infection. The serum samples were screened for antibodies against Brucella spp. by the Rose-Bengal test (RBT), and all RBT-positive sera were re-tested by the 2-mercaptoethanol test (2-ME). A herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. The prevalences of infected herds and infected animals in Paraná State were 4.0 percent [3.2-4.8 percent] and 1.7 percent [1.1-2.4 percent], respectively. In the regions, the prevalences of infected herds and animals were: region 1, 14.7 percent [10.9-19.2 percent] and 2.8 percent [1.2-4.4 percent]; region 2, 8.8 percent [5.9-12.6 percent] and 2.4 percent [1.0-3.8 percent]; region 3, 3.4 percent [1.6-6.1 percent] and 0.85 percent [0.21-1.5 percent]; region 4, 2.3 percent [0.94-4.8 percent] and 0.83 percent [0.02-1.6 percent]; region 5, 2.3 percent [0.94-4.7 percent] and 1.7 percent [0.06-3.3 percent]; region 6, 0.34 percent [0-1.9 percent] and 0.09 percent [0-0.27 percent]; and region 7, 1.0 percent [0.21-2.9 percent] and 2.2 percent [0-6,0 percent]. The risck factors (odds ratio, OR) associated with the presence of the infection were: purchase of animals for breeding (OR= 2.20 [1.42-3.40]) and pasture rental practice (OR=2.45 [1.54-3.90]).

Anti-inflammatory activity of the apolar extract from the seaweed Galaxaura marginata (Rhodophyta, Nemaliales)

The red seaweed Galaxaura marginata (Ellis & Solander) Lamouroux, well known by the antibacterial activity of its polar extract and the cytotoxic activity of its oxygenated desmosterol, showed anti-inflammatory action in its apolar fraction. Topical anti-inflammatory activity was observed in samples collected at São Sebastião channel, northern littoral of São Paulo State, Brazil. The apolar extract and its fractions obtained through Thin-Layer Chromatography (TLC) reduced the topical inflammation produced by croton oil in mouse ear. Such data indicated that the apolar extract from the marine red alga G. marginata displayed anti-inflammatory activity (since 1mg/ear extract reduced 95±0.5 percent inflammation), which could be the result of the synergic activity of the four fractions present in the apolar extract.

Dairy cow abortion associated with Neospora caninum and other infectious agents

Trinta e cinco vacas de rebanhos leiteiros da região Norte do estado do Paraná, com histórico de abortamento, foram pesquisadas sorologicamente para verificar a presença de anticorpos contra Neospora caninum, Toxoplasma gondii, Leptospira spp., Brucella abortus, BHV-1 e BVDV. Vinte e uma vacas apresentaram títulos sorológicos compatíveis com infecção. Todas elas, soropositivas para N. caninum, foram também soropositivas para outros agentes infecciosos, sugerindo a possibilidade de associação desses agentes nos problemas reprodutivos de bovinos, no estado do Paraná.

Anti-inflammatory and antispasmodic activity of Ipomoea imperati (Vahl) Griseb (Convolvulaceae)

Ipomoea imperati (Convolvulaceae) lives on the sandy shores of the Brazilian coast and in other areas of the world. The anti-inflammatory activity of a methanol-water extract of the leaves of I. imperati was investigated in experimental models of acute and subchronic inflammation. Topical application of the extract (10 mg/ear) inhibited mouse ear edema induced by croton oil (89.0 ± 1.3 percent by the lipid fraction with an IC50 of 3.97 mg/ear and 57.0 ± 1.3 percent by the aqueous fraction with an IC50 of 3.5 mg/ear) and arachidonic acid (42.0 ± 2.0 percent with an IC50 of 4.98 mg/ear and 31.0 ± 2.0 percent with an IC50 of 4.72 mg/ear). Phospholipase A2, purified from Apis mellifera bee venom, was also inhibited by the extract (5.0 mg/ml lipid and aqueous fraction) in vitro in a dose-dependent manner (85 percent by the lipid fraction with an IC50 of 3.22 mg/ml and 25 percent by the aqueous fraction with an IC50 of 3.43 mg/ml). The methanol-water extract of I. imperati (1000 mg/kg) administered by the oral route also inhibited the formation of cotton pellet-induced granulomas (73.2 ± 1.2 percent by the lipid fraction and 56.14 ± 2.7 percent by the aqueous fraction) and did not cause gastric mucosal lesions. I. imperati extracts (10 mg/ml) also inhibited in a dose-dependent manner the muscle contractions of guinea pig ileum induced by acetylcholine and histamine (IC50 of 1.60 mg/ml for the lipid fraction and 4.12 mg/ml for the aqueous fraction). These results suggest the use of I. imperati as an anti-inflammatory and antispasmodic agent in traditional medicine

Toxicity of puffer fish - two species(Lagocephalus laevigatus, LINAEUS 1766 and Sphoeroides spengleri, BLOCH 1785) from the southeastern Brazilian coast

In Brazil, where puffer fish are considered poisonous, there are few documented cases on human consumption and consequent poisoning. In this study, toxicity of two puffer fish species from the Brazilian coast was examined. Specimens of Sphoeroides spengleri and Lagocephalus laevigatus were caught in Säo Sebastiäo Channel (North coast of Säo Paulo State, Brazil) between January 1996 and May 1997. Acidic ethanol extracts from muscle and skin plus viscera were tested for mice acute toxicity using the standard method of Kawabata. Polar extracts of S. spengleri showed high toxicity up to 946 MU/g. Extracts from L. laevigatus showed very low levels of toxicity, never exceeding 1.7 MU/g. All extracts from both species blocked amielinic nerve fiber evoked impulses of crustacean legs; this effect reverted on washing similar to the standard tetrodotoxin TTX. The aqueous extract solutions were partially purified using an ionic exchange column (Amberlit GC-50) followed by treatment with activated charcoal (Norit-A). The presence of TTX and their analogs in the semi-purified extracts were confirmed by HPLC and mass spectrometry (MALDI-TOF).

Evaluation of the cholinomimetic actions of trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana (Gastropoda, Opisthobranchia)

Trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana, negatively modulates vagal response, indicating a probable ability to inhibit cholinergic responses. In the present study, the pharmacological profile of trimethylsulfonium was characterized on muscarinic and nicotinic acetylcholine receptors. In rat jejunum the contractile response induced by trimethylsulfonium (pD2 = 2.46 + or - 0.12 and maximal response = 2.14 + or - 0.32 g) was not antagonized competitively by atropine. The maximal response (Emax) to trimethylsulfonium was diminished in the presence of increasing doses of atropine (P<0.05), suggesting that trimethylsulfonium-induced contraction was not related to muscarinic stimulation, but might be caused by acetylcholine release due to presynaptic stimulation. Trimethylsulfonium displaced [³H]-quinuclidinyl benzilate from rat cortex membranes with a low affinity (Ki = 0.5 mM). Furthermore, it caused contraction of frog rectus abdominis muscles (pD2 = 2.70 + or - 0.06 and Emax = 4.16 + or - 0.9 g), which was competitively antagonized by d-tubocurarine (1, 3 or 10 æM) with a pA2 of 5.79, suggesting a positive interaction with nicotinic receptors. In fact, trimethylsulfonium displaced [³H]-nicotine from rat diaphragm muscle membranes with a Ki of 27.1 æM. These results suggest that trimethylsulfonium acts as an agonist on nicotinic receptors, and thus contracts frog skeletal rectus abdominis muscle and rat jejunum smooth muscle via stimulation of postjunctional and neuronal prejunctional nicotinic cholinoreceptors, respectively

Identification of hemolytic and neuroactive fractions in the venom of the sea anemone Bunodosoma cangicum

Sea anemones are a rich source of biologically active substances. In crayfish muscle fibers, Bunodosoma cangicum whole venom selectively blocks the I K(Ca) currents. In the present study, we report for the first time powerful hemolytic and neuroactive effects present in two different fractions obtained by gel-filtration chromatography from whole venom of B. cangicum. A cytolytic fraction (Bcg-2) with components of molecular mass ranging from 8 to 18 kDa elicited hemolysis of mouse erythrocytes with an EC50 = 14 æg/ml and a maximum dose of 22 æg/ml. The effects of the neuroactive fraction, Bcg-3 (2 to 5 kDa), were studied on isolated crab nerves. This fraction prolonged the compound action potentials by increasing their duration and rise time in a dose-dependent manner. This effect was evident after the washout of the preparation, suggesting the existence of a reversible substance that was initially masking the effects of an irreversible one. In order to elucidate the target of Bcg-3 action, the fraction was applied to a tetraethylammonium-pretreated preparation. An additional increase in action potential duration was observed, suggesting a blockade of a different population of K+ channels or of tetraethylammonium-insensitive channels. Also, tetrodotoxin could not block the action potentials in a Bcg-3-pretreated preparation, suggesting a possible interaction of Bcg-3 with Na+ channels. The present data suggest that B. cangicum venom contains at least two bioactive fractions whose activity on cell membranes seems to differ from the I K(Ca) blockade described previously

Produtos naturais marinhos: características dos envenenamentos alimentares e substâncias de interesse farmacológico / Marine products: food poisoning

Há um crescente interesse na pesquisa de novas substâncias, eficazes no combate à determinadas doenças, a partir das florestas e dos recursos presentes no mar. Este, em sua imensidäo, guarda muitos segredos ainda por serem descobertos, sendo um deles, o que se refere às substâncias que seus habitantes produzem ou armazenam, sejam para serem utilizadas para a sua comunicaçäo, defesa, predaçäo, reproduçäo ou simplesmente como produto de seu metabolismo. Além disto, uma mesma substância que, por um lado, pode apresentar-se como um composto tóxico, por outro, pode ser a esperança para o tratamento e possivelmente a cura de determinadas doenças.

Cytotoxic activity of a methanol extract of Phallusia nigra (Tunicata, Ascidiacea)

Tunicates have been reported to be a rich source of biologically active compounds. In this study, we demonstrate the presence of cytotoxic substances in Phallusia nigra, a common tunicate from Brazilian coastal waters. An extract of tunicate tissue was obtained by homogenizing the visceral organs from 50 specimens in methanol, followed by filtration and concentration in a rotary vacuum evaporator. Finally, the concentrate was partitioned with chloroform to remove lipids. The resulting extract possessed antimitotic and hemolytic activity. The former was demonstrated as a delay in the development of sea urchin eggs by partially inhibiting the process of cleavage (first cleavage, EC50 ñ SEM = 3.44 ñ 0.84 mg/ml). The <500 molecular fraction of the extract obtained by ultrafiltration also inhibited cell proliferation (the number of viable cells was decreased by 68 per cent with 500 mug/ml) and DNA synthesis of T47D cells derived from human breast carcinoma as measured by [3H]-thymidine incorporation (66 per cent of the control value after 24-h incubation with 100 mug/ml). Dose-dependent hemolysis obtained with P. nigra extract on mouse erythrocytes had an EC50 ñ SEM = 1.12 ñ 0.02 mglml for a 0.5 per cent erythrocyte suspension. Hemolysis could be reduced by pre-incubating the cells with choline-containing phospholipid. Sphingomyelin (40 mug/ml) increased the EC50 by twofold to 2.86 ñ 0.04 mg/ml, but phosphatidylcholine (80 mug/ml) did not modify hemolysis.

Occurrence of tetrodotoxin and paralytic shellfish toxins in Phallusia nigra (Tunicata, Ascidiacea) from the brazilian coast

We have already shown the presence of guanidine neurotoxins in calcareous red algae and mussels collected in the Säo Sebastiäo channel State of Säo Paulo,Brazil). It is known that these neurotoxins comprise more than 25 analogues such as tetrodotoxin (TTX) and derivatives plus the paralytic shellfish toxins (PST) found in a variety of marine, freshwater and amphibious species. Filter feeding animals generally possess large amounts of these neurotoxins. The tunicates are sessil marine animals with a high rate of sea water filtration. The tunics and siphons of 50 specimens of Phallusia nigra were dissected and the visceral organs were immersed in methanol containing acetic acid 0.02 N ph 5.0. The extract was prepared by homogenization, filtration and the methanolic phase was concentrated under reduced pressure and defatted with chloroform. The polar phase was evaporated and the residue dissolved in deionized water for further purification in ionic-exchange resin column (Bio-Gel P-2) and HPLC analysis. The extract showed paralytic effects on mouse assay (26.9 MU/100mg) and on crustacean isolated nerve preparations. The chemical analysis for TTX and PST revealed toxins with retention times similar to gonyautoxins, saxitoxins and TTX. These findings are important to explain future toxin envenoming outbreaks on the Brazilian coast.

Detection of cytotoxins of Escherichia coli strains isolated from piglets, in vero cells assay

Neste estudo, a produçäo de toxinas por 91 amostras de E. coli, isoladas de leitöes com colibacilose, foi testada em cultivo de células VERO. Observou-se que 20 (22,0 por cento) das amostras foram citotóxicas e seis (6,6 por cento) foram citotônicas; somente uma amostra foi citotóxica e citotônica simultaneamente. Sete (87,5 por cento) das amostras isoladas de doença do edema produziram verotoxina. Todas as amostras citotônicas foram inativadas à 60§C/15 min e as citotóxicas, à 70§C/15 min

Resistance and plasmid profile of coagulase negative staphylococci isolated from bovine subclinical mastitis in Brazil

Estudou-se a resistência a agentes antimicrobianos e o perfil plasmidial de amostras de estafilococos coagulase negativos (ECN) isolados de mastite subclínica bovina. Dos 33 ECN isolados, 57 por cento foram resistentes a sulfametoxazol, 42 por cento ao trimetoprim, 33 por cento à tetraciclina, 27 por cento à lincomicina e 18 por cento à penicilina. Nenhuma amostra foi resistente a tetraciclina, 27 por cento à lincomicina e 18 por cento à penicilina. Nenhuma amostra foi resistente a amicacina, cefalotina, neocina, oxacilina e vancomicina. Detectaram-se plasmídios em 24 (72 por cento) destas amostras, variando em número de um a nove por cultura, totalizando 76 plasmídios com 48 diferentes pesos moleculares. Em algumas amostras, mediante experimentos de cura e transformaçäo, concluiu-se que o determinante genético de resistência à tetraciclina, eritomicina e cloranfenicol está localizado em plasmídios específicos

Antimitotic action of extracts of Petiveria alliacea on sea urchin egg development

The hydroethanol extract of the roots of Petiveria alliacea L. (Phytolaccaceae) has been investigated previously as an antitumor agent against mouse Ehrlich ascites. The extract and its methanol, butanol and ether fractions exhibited an antimitotic effect on sea urchin egg development. The aqueous fraction did not produce inhibition of cell cleavage. At the first cleavage the inhibition, at the lowest concentration (10 micrograms/ml), produced by the ether fraction was 42 per cent , whereas the inhibition produced by the total extract and by the other fractions was only 5 to 10 per cent showing that the ether fraction was the most active. Even at higher concentrations the butanol and methanol fractions inhibit the cleavage about 30 per cent . At the first cleavage, the ED50 of the hydroethanol extract and of the ether fraction were 45.02 and 12.40 micrograms/ml, respectively. Furthermore, in the second cleavage, the hydroethanol extract was about twice as potent as the methanol or butanol fractions (ED50 of 22.40, 44.80 and 54.10 micrograms/ml, respectively)

Effect of beta-myrcene on pentobarbital sleeping time

Evidence that beta-myrcene (MYR) interferes with the metabolic activation of premutagens has been provided by in vitro studies. In order to determine whether MYR also interferes with the in vivo metabolism of xenobiotics, thereby modifying pharmacological responses to drugs, we investigated the effects of this monoterpene on pentobarbital (PT) sleeping time in rats. Two experiments were carried out. In the first, a single dose of MYR (0.25, 0.5 or 1.0 g/kg po) was given 1 h before PT (40 mg/kg ip). No effect was observed with the two lowest doses, but the highest MYR dose given 1 h before PT increased the PT-induced sleeping time (131 +/- 15 min vs 64 +/- 15 min for controls, mean +/- SD). In the second experiment, male rats were treated with MYR (1.0 g/kg po once a day) for 14 days and injected with PT (40 mg/kg ip) 24 h after the last dose of MYR. Repeated treatment with MYR markedly reduced PT sleeping time compared to the vehicle-treated control group (21 +/- 13 min vs 35 +/- 19 min for controls, mean +/- SD). These results indicate that MYR interferes with the in vivo barbiturate metabolism and support the view that MYR induces the phenobarbital-inducible cytochrome P-450 (P-450 2B subfamily) enzymes in the rat

Plasmid profile of Staphylococcus hyicus isolated from swine exudative epidermitis in Brazil

Staphylococcus hyicus isolados de leitöes com lesöes de pele foram estudados no que se refere aos seus plasmídios e resistência a agentes antimicrobianos. Plasmídios de diferentes pesos moleculares foram detectados nas seis amostras de Staphylococcus hyicus. Todas as amostras mostraram resistência à tetraciclina e um pequeno plasmídio de 4.0 Kb, com uma exceçäo. Experimentos de cura e transformaçäo demonstraram que este plasmídio abriga o determinante genético para resistência à tetraciclina nas amostras estudadas