In vitro and in silico evaluation of the schistosomicidal activity of eugenol derivatives using biochemical, molecular, and morphological tools

Background Eugenol shows both antibacterial and antiparasitic activities, suggesting that it might be evaluated as an option for the treatment of praziquantel-resistant schistosome. Methods The in vitro activities of three eugenol derivatives (FB1, FB4 and FB9) on adult worms from Schistosoma mansoni were examined by fluorescence and scanning electron microscopy to analyze effects on the excretory system and integument damage, respectively. Biochemical tests with verapamil (a calcium channel antagonist) and ouabain (a Na+/K+-ATPase pump inhibitor) were used to characterize eugenol derivative interactions with calcium channels and the Na+/K+-ATPase, while in silico analysis identified potential Na+/K+-ATPase binding sites. Results The compounds showed effective doses (ED50) of 0.324 mM (FB1), 0.167 mM (FB4), and 0.340 mM (FB9). In addition, FB4 (0.322 mM), which showed the lowest ED50, ED90 and ED100 (p < 0.05), caused the most damage to the excretory system and integument, according to both fluorescence and scanning electron microscopy analysis. The death of adult worms was delayed by ouabain treatment plus FB1 (192 versus 72 hours) and FB9 (192 versus 168 hours), but the response to FB4 was the same in the presence or absence of ouabain. Besides, no changes were noted when all of the eugenol derivatives were combined with verapamil. Moreover, FB1 and FB9 inhibited Na+/K+-ATPase activity according to in silico analysis but FB4 did not show a time-dependent relationship and may act on targets other than the parasite Na+/K+-ATPase. Conclusion Eugenol derivatives, mainly FB4 when compared to FB1 and FB9, seem to act more effectively on the integument of adult S. mansoni worms.(AU)

Study on the mechanisms of Suaeda rigida polysaccharides on the heart inhibition and skeletal muscle promotion in the frog / [Estudo sobre os mecanismos dos polissacarídeos de Suaeda rigida na inibição do coração e promoção da musculatura esquelética no sapo]

The objectives of this study were to investigate the effects of different concentrations of Suaeda rigida polysaccharides (SRPs) on the physiological characteristics of the frog heart and gastrocnemius muscle, compare their similarities and differences, and analyze the mechanisms. CaCl2 and acetylcholine (Ach) were selected respectively to be co-incubated with the high concentration SRPs to observe the effects on the heart contraction of frog. The effects of different concentrations of the SRPs on the activities of acetylcholinesterase (A-CHE), Na+-K+-ATPase and Ca2+-Mg2+-ATPase in the isolated frog heart were detected by UV-Vis spectrophotometry. The gastrocnemius muscle was immersed in the high concentration of SRPs for 10 min, and the systolic indexes were recorded. The effects of SRPs on the Ach content and A-CHE activity at the sciatic nerve-gastrocnemius junction were determined by UV-Vis spectrophotometry and enzyme-linked immunosorbent assay (ELISA). The results showed that the SRPs had significant inhibitory effects on the contractile amplitude of isolated heart and the contractile amplitude induced by CaCl2 and Ach, respectively (P<0.01). The activity of Ca2+-Mg2+-ATPase was significantly promoted, and the activity of A-CHE was significantly inhibited (P<0.01). The contraction amplitude, contraction rate, relaxation rate of gastrocnemius muscle and the Ach content at the junction of sciatic nerve-gastrocnemius muscle were significantly increased (P<0.01), and the activity of A-CHE at the junction was significantly inhibited (P<0.01) by the SRPs. All the results suggested that the SRPs could inhibit the contraction of heart and promote the contraction and relaxation of skeletal muscle. The mechanism was related to blocking the fast INa channel, inhibiting the ICa-L and activating the M receptors of myocardial membrane and then inhibiting external Ca2+ influx, increasing Ca2+-Mg2+-ATPase activity, decreasing a-che activity.

Os objetivos deste estudo foram investigar os efeitos de diferentes concentrações de Suaeda rigida polissacarídeos (SRPs) sobre as características fisiológicas do coração de rã e do músculo gastrocnêmio, comparar suas semelhanças e diferenças, e analisar os mecanismos. CaCl2 e acetilcolina (Ach) foram selecionados respectivamente para serem co-incubados com os SRPs de alta concentração para observar os efeitos sobre a contração do coração de rã. Os efeitos das diferentes concentrações dos SRPs sobre as atividades da acetilcolinesterase (A-CHE), Na+-K+-ATPase e Ca2+-Mg2+-ATPase no coração isolado de rã foram detectados pela espectrofotometria UV-Vis. O músculo gastrocnêmio foi imerso na alta concentração de SRP por 10 min, e os índices sistólicos foram registrados. Os efeitos das SRPs no conteúdo de Ach e na atividade de A-CHE na junção nervo-gastrocnêmio ciático foram determinados pela espectrofotometria UV-Vis e pelo ensaio de imunoabsorção enzimática (ELISA). Os resultados mostraram que os SRPs tiveram efeitos inibidores significativos sobre a amplitude contrátil do coração isolado e a amplitude contrátil induzida por CaCl2 e Ach, respectivamente (P<0,01). A atividade do Ca2+-Mg2+-ATPase foi significativamente promovida e a atividade do A-CHE foi significativamente inibida (P<0,01). A amplitude de contração, a taxa de contração, a taxa de relaxamento do músculo gastrocnêmio e o conteúdo de Ach na junção do músculo nervo ciático-gastrocnêmio foram significativamente aumentados (P<0,01), e a atividade do A-CHE na junção foi significativamente inibida (P<0,01) pelas SRPs. Todos os resultados sugeriram que os SRPs poderiam inibir a contração do coração e promover a contração e o relaxamento do músculo esquelético. O mecanismo estava relacionado ao bloqueio do canal INa rápido, inibindo a ICa-L e ativando os receptores M da membrana miocárdica e depois inibindo o influxo externo de Ca2+, aumentando a atividade de Ca2+-Mg2+-ATPase, diminuindo a atividade a-che.

Subclinical intramammary infection does not affect bovine milk ethanol stability / Infecção intramamária subclínica não afeta a estabilidade do leite bovino

The present study hypothesized that intramammary infection (IMI) might reduce milk ethanol stability (MES), mainly when IMI is caused by major pathogens. Thus, this study evaluated the effect of IMI on bovine MES using a natural exposure experimental design. Ninety-four lactating cows from five dairy herds were selected once they were determined to have an IMI, based on milk bacteriological culturing with positive isolation and somatic cell count (SCC) > 200×103 cells/mL in two out of three composite milk samples collected during three consecutive weeks. After selection, cows were sampled a second time (within two weeks) for evaluation at mammary quarter level (n = 326): milk yield (kg/quarter/day), MES, composition (fat, protein, lactose, casein, total solids and solids-non-fat), and bacteriologic culture. The effect of subclinical mastitis on MES was tested by two models: 1) comparison of healthy vs. infected quarters; and 2) comparison of contralateral mammary quarter within cow. The only milk composition variable associated with MES was lactose (r = 0.18; P < 0.01). Subclinical IMI did not affect MES when the comparison was performed using both models (1 and 2). Likewise, MES did not change when infected quarters were sorted into two groups of pathogens (major, minor and infrequent; and contagious, environmental, minor and infrequent) and compared with healthy mammary quarters. Considering the results of both models, subclinical IMI did not affect MES of dairy cows.(AU)

Neste trabalho investigou-se a hipótese de que a infecção intramamária (IIM) poderia reduzir a estabilidade do leite ao etanol (ELA), principalmente quando a IIM é causada por agentes primários. Assim, em um experimento de exposição natural, foi avaliado o efeito da IIM sobre a ELA em bovinos. Noventa e quatro vacas em lactação de cinco rebanhos leiteiros foram selecionadas por apresentar IIM, segundo resultados de cultura bacteriológica de amostras compostas de leite (isolamento positivo) e contagem de células somáticas (CCS) > 200×103 células/mL em pelo menos duas de três coletas semanais consecutivas. Após essa seleção, as vacas foram amostradas pela segunda vez (dentro de duas semanas) para avaliação da IIM em amostras de leite coletadas por quarto mamário (n = 326): produção de leite (kg/quarto/dia), ELA, composição (gordura, proteína, lactose, caseína, sólidos totais e sólidos não gordurosos) e cultura bacteriológica. O efeito da mastite subclínica sobre a ELA foi testada por dois modelos: 1) comparação de quarto sadio versus infectado; e 2) comparação de quartos mamários contralaterais. A única variável de composição do leite associada à ELA foi a lactose (r = 0,18; P < 0,01). A IIM subclínica não afetou a ELA quando a comparação foi realizada utilizando-se os dois modelos (1 e 2); bem como a ELA não foi alterada quando os quartos infectados foram classificados em grupos de agentes patogênicos (primários, secundários e infrequentes; ou contagiosos, ambientais, secundários e infrequentes) e comparados com os quartos mamários sadios. Os resultados obtidos com os dois modelos empregados demonstraram que a IIM subclínica não afetou a ELA de vacas leiteiras.(AU)

Subclinical intramammary infection does not affect bovine milk ethanol stability / Infecção intramamária subclínica não afeta a estabilidade do leite bovino

The present study hypothesized that intramammary infection (IMI) might reduce milk ethanol stability (MES), mainly when IMI is caused by major pathogens. Thus, this study evaluated the effect of IMI on bovine MES using a natural exposure experimental design. Ninety-four lactating cows from five dairy herds were selected once they were determined to have an IMI, based on milk bacteriological culturing with positive isolation and somatic cell count (SCC) > 200×103 cells/mL in two out of three composite milk samples collected during three consecutive weeks. After selection, cows were sampled a second time (within two weeks) for evaluation at mammary quarter level (n = 326): milk yield (kg/quarter/day), MES, composition (fat, protein, lactose, casein, total solids and solids-non-fat), and bacteriologic culture. The effect of subclinical mastitis on MES was tested by two models: 1) comparison of healthy vs. infected quarters; and 2) comparison of contralateral mammary quarter within cow. The only milk composition variable associated with MES was lactose (r = 0.18; P < 0.01). Subclinical IMI did not affect MES when the comparison was performed using both models (1 and 2). Likewise, MES did not change when infected quarters were sorted into two groups of pathogens (major, minor and infrequent; and contagious, environmental, minor and infrequent) and compared with healthy mammary quarters. Considering the results of both models, subclinical IMI did not affect MES of dairy cows.(AU)

Neste trabalho investigou-se a hipótese de que a infecção intramamária (IIM) poderia reduzir a estabilidade do leite ao etanol (ELA), principalmente quando a IIM é causada por agentes primários. Assim, em um experimento de exposição natural, foi avaliado o efeito da IIM sobre a ELA em bovinos. Noventa e quatro vacas em lactação de cinco rebanhos leiteiros foram selecionadas por apresentar IIM, segundo resultados de cultura bacteriológica de amostras compostas de leite (isolamento positivo) e contagem de células somáticas (CCS) > 200×103 células/mL em pelo menos duas de três coletas semanais consecutivas. Após essa seleção, as vacas foram amostradas pela segunda vez (dentro de duas semanas) para avaliação da IIM em amostras de leite coletadas por quarto mamário (n = 326): produção de leite (kg/quarto/dia), ELA, composição (gordura, proteína, lactose, caseína, sólidos totais e sólidos não gordurosos) e cultura bacteriológica. O efeito da mastite subclínica sobre a ELA foi testada por dois modelos: 1) comparação de quarto sadio versus infectado; e 2) comparação de quartos mamários contralaterais. A única variável de composição do leite associada à ELA foi a lactose (r = 0,18; P < 0,01). A IIM subclínica não afetou a ELA quando a comparação foi realizada utilizando-se os dois modelos (1 e 2); bem como a ELA não foi alterada quando os quartos infectados foram classificados em grupos de agentes patogênicos (primários, secundários e infrequentes; ou contagiosos, ambientais, secundários e infrequentes) e comparados com os quartos mamários sadios. Os resultados obtidos com os dois modelos empregados demonstraram que a IIM subclínica não afetou a ELA de vacas leiteiras.(AU)

Effects of aquaporin 4 and inward rectifier potassium channel 4.1 on medullospinal edema after methylprednisolone treatment to suppress acute spinal cord injury in rats

Purpose: To investigate the effects of aquaporin 4 (AQP4) and inward rectifier potassium channel 4.1 (Kir4.1) on medullospinal edema after treatment with methylprednisolone (MP) to suppress acute spinal cord injury (ASCI) in rats.Methods: Sprague Dawley rats were randomly divided into control, sham, ASCI, and MP-treated ASCI groups. After the induction of ASCI, we injected 30 mg/kg MP via the tail vein at various time points. The Tarlov scoring method was applied to evaluate neurological symptoms, and the wet-dry weights method was applied to measure the water content of the spinal cord.Results: The motor function score of the ASCI group was significantly lower than that of the sham group, and the spinal water content was significantly increased. In addition, the levels of AQP4 and Kir4.1 were significantly increased, as was their degree of coexpression. Compared with that in the ASCI group, the motor function score and the water content were significantly increased in the MP group; in addition, the expression and coexpression of AQP4 and Kir4.1 were significantly reduced.Conclusion: Methylprednisolone inhibited medullospinal edema in rats with acute spinal cord injury, possibly by reducing the coexpression of aquaporin 4 and Kir4.1 in medullospinal tissues.(AU)

Mass fingerprinting and electrophysiological analysis of the venom from the scorpion Centruroides hirsutipalpus (Scorpiones: Buthidae)

Background Centruroides hirsutipalpus, of the family Buthidae, is a scorpion endemic to the Western Pacific region of Mexico. Although medically important, its venom has not yet been studied. Therefore, this communication aims to identify their venom components and possible functions. Methods Fingerprinting mass analysis of the soluble venom from this scorpion was achieved by high-performance liquid chromatography and electrospray mass spectrometry. Furthermore, the soluble venom and its toxic effects were evaluated extensively via electrophysiological assays in HEK cells expressing human voltage-gated Na+ channels (hNav 1.1 to Nav1.6), CHO cells expressing hNav 1.7, potassium channel hERG 1 (Ether-à-go-go-related-gene) and the human K+-channel hKv1.1. Results The separation of soluble venom produced 60 fractions from which 83 distinct components were identified. The molecular mass distribution of these components varies from 340 to 21,120 Da. Most of the peptides have a molecular weight between 7001 and 8000 Da (46% components), a range that usually corresponds to peptides known to affect Na+ channels. Peptides with molecular masses from 3000 to 5000 Da (28% of the components) were identified within the range corresponding to K+-channel blocking toxins. Two peptides were obtained in pure format and completely sequenced: one with 29 amino acids, showing sequence similarity to an "orphan peptide" of C. limpidus, and the other with 65 amino acid residues shown to be an arthropod toxin (lethal to crustaceans and toxic to crickets). The electrophysiological results of the whole soluble venom show a beta type modification of the currents of channels Nav1.1, Nav1.2 and Nav1.6. The main effect observed in channels hERG and hKv 1.1 was a reduction of the currents. ..(AU)

Mass fingerprinting and electrophysiological analysis of the venom from the scorpion Centruroides hirsutipalpus (Scorpiones: Buthidae)

Background Centruroides hirsutipalpus, of the family Buthidae, is a scorpion endemic to the Western Pacific region of Mexico. Although medically important, its venom has not yet been studied. Therefore, this communication aims to identify their venom components and possible functions. Methods Fingerprinting mass analysis of the soluble venom from this scorpion was achieved by high-performance liquid chromatography and electrospray mass spectrometry. Furthermore, the soluble venom and its toxic effects were evaluated extensively via electrophysiological assays in HEK cells expressing human voltage-gated Na+ channels (hNav 1.1 to Nav1.6), CHO cells expressing hNav 1.7, potassium channel hERG 1 (Ether-à-go-go-related-gene) and the human K+-channel hKv1.1. Results The separation of soluble venom produced 60 fractions from which 83 distinct components were identified. The molecular mass distribution of these components varies from 340 to 21,120 Da. Most of the peptides have a molecular weight between 7001 and 8000 Da (46% components), a range that usually corresponds to peptides known to affect Na+ channels. Peptides with molecular masses from 3000 to 5000 Da (28% of the components) were identified within the range corresponding to K+-channel blocking toxins. Two peptides were obtained in pure format and completely sequenced: one with 29 amino acids, showing sequence similarity to an "orphan peptide" of C. limpidus, and the other with 65 amino acid residues shown to be an arthropod toxin (lethal to crustaceans and toxic to crickets). The electrophysiological results of the whole soluble venom show a beta type modification of the currents of channels Nav1.1, Nav1.2 and Nav1.6. The main effect observed in channels hERG and hKv 1.1 was a reduction of the currents. ..

ESTRUTURA ESPAÇO-TEMPORAL DA COMUNIDADE ZOOPLANCTÔNICA DO RESERVATÓRIO DA USINA HIDRELÉTRICA DE TUCURUÍ (PARÁ BRASIL)

Os reservatórios são uma realidade no Brasil, tais ambientes possuem alto dinamismo e apresentam importância estratégica na produção de energia e abastecimento e são utilizados para diversos usos, que interferem na qualidade da água, funcionamento do ecossistema e estrutura das comunidades aquáticas. A comunidade zooplanctônica em reservatórios apresenta papel importante na transferência de energia e regeneração de nutrientes, e sua composição, estrutura, dinâmica e sucessão de espécies são influenciadas pelas condições físicas, químicas e biológicas. Desta forma, objetivou-se caracterizar a estrutura espaçotemporal da comunidade zooplanctônica e sua relação com as variáveis ambientais no reservatório da Usina Hidreletrica de Tucuruí (Pará, Brasil) nos meses de fevereiro, julho e dezembro de 2011. Foram realizadas amostragens em 10 estações de coleta ao longo do reservatório. As amostras foram coletadas com redes de plâncton 64 m juntamente com os parâmetros ambientais. De acordo com as análises físico-químicas foi observado um gradiente ambiental relacionado ao período sazonal. Em relação ao estado trófico, a maioria dos pontos amostrados foi classificado como eutrófico. Com 156 taxa de organismos zooplanctônicos identificados, os rotíferos apresentaram a maior riqueza de espécies (88), seguidos de cladóceros (24) e copépodas (13), o que está de acordo com o padrão de distribuição para corpos hídricos tropicais. A riqueza variou de forma significante em relação aos meses, e o índice de Simpson foi significativamente maior em fevereiro, enquanto que a densidade de organismos não mostrou variação significativa. A densidade foi dominada pela espécie de rotífero K. americana e náuplios durante todo estudo, contribuindo com cerca de 50% da abundância. De acordo com a análise de agrupamento, foi observado que a abundância zooplanctônica esteve corrrelacionada a variação espacial da UHE de Tucuruí. A RDA mostrou que o gradiente ambiental está relacionado ao tempo e o zooplâncton ao espaço. As espécies Monostyla sp., Keratella quadratica, Brachionus caudatus austrogenitus estiveram relacionados aos meses de dezembro (canal e interior). Thermocyclops sp. esteve relacionadas ao interior (fevereio/julho). Filinia longiseta, Testudinella patina, Asplancha sp1, A.ovalis, Lecane lunaris, Trichocerca chattoni, Trichocerca sp., Ceriodaphinia cornuta dubia e Holopedium amazonicum, Cyclopoida sp3 foram fortemente relacionados ao canal (fevereiro/julho). Demonstrando a formação de habitats específicos que estruturam a comunidade zoolanctônica da UHE de Tucuruí durante o período analisado.

Reservoirs are a reality in Brazil, such environments are highly dynamic and have strategic importance and are used for various uses, which interfere with water quality, ecosystem functioning and the structure of aquatic communities. These lentic environments are suitable for the development of planktonic populations. The zooplankton community in reservoirs plays an important role in energy transfer and nutrient regeneration, and their composition, structure, dynamics and succession of species are influenced by physical, chemical and biological conditions. Thus, the objective was to characterize the spatio-temporal structure of the zooplankton community and its relationship with the environmental variables in the reservoir of the Tucuruí HPP (Pará, Brazil) in the months of February, July and December 2011. Samples were performed in 10 stations of collection along the reservoir. The samples were collected with 64 m plankton nets together with the environmental parameters that were measured using a multiparametric probe. Physical-chemical analyzes revealed the formation of an environmental gradient related to the seasonal period. In the assessment of the trophic state, the environment had eutrophic behavior. With 156 taxa of zooplanktonic organisms identified, where the rotifers had the highest species richness with 88 taxons, followed by cladocerans (24) and copepods (13), which is in line with the typical pattern of tropical water bodies. The richness varied significantly in relation to the months, and the Simpson index was significantly higher in February, while the density of organisms did not show significant variation. The density was dominated by the rotifer species K. americana and nauplii, who throughout the study were contributing 50% of the abundance. Cluster analysis showed that the abundance of zooplankton was related to space variation of the UHE of Tucuruí. Canonical redundancy analysis showed that the environmental gradient is related to time and zooplankton is related to space, resembling the cluster. Monostyla sp., Keratella quadratica, Brachionus caudatus austrogenitus were related to December (canal and interior). Thermocyclops sp was related to the interior (February / July). Filinia longiseta, Testudinella patina, Asplancha sp1, A.ovalis, Lecane lunaris, Trichocerca chattoni, Trichocerca sp., Ceriodaphinia cornuta dubia and Holopedium amazonicum, Cyclopoida sp3 were strongly related to the channel (February / July). Demonstrating the formation of specific habitats that structure the zoolanctonic community of the UHE of Tucuruí during the analysed period.

Growth of the Cichla temensis Humboldt, 1821 (Perciformes: Cichlidae) from the middle rio Negro, Amazonas, Brazil

This study aimed to estimate age and growth of the peacock bass Cichla temensis from the rio Negro (Brazilian Amazonia) by analyzing scale annuli. Specimens were captured between October 2011 and September 2012 in the main channel of the river and in adjacent lakes in the municipality of Barcelos, AM, Brazil. Six growth checks were identified on the scales of specimens. The annual variation in body condition observed suggests that fat is accumulated during the dry season. Results for the GSI (gonadosomatic index) showed that peak reproduction occurred in the receding-water period, indicating that the fish had energy deficiencies as a result of reproductive activity. RMI (relative marginal increment) analysis revealed that an annulus is formed once a year during the receding-water period. The population parameters estimated were L50 (length at sexual maturity) = 31.11 cm, L∞ (asymptotic length) = 68.05 cm, k (growth coefficient) = 0.20.year-1 and A0.95 (longevity) = 14 years. Our results corroborate the validity of using growth rings in scales as indicators to estimate the age and growth rate of Cichla temensis in the middle rio Negro.(AU)

Este estudo teve como objetivo estimar a idade e o crescimento do tucunaré Cichla temensis do rio Negro (Amazônia brasileira) por meio de anéis nas escamas. Os espécimes foram capturados entre outubro de 2011 e setembro de 2012, no canal principal e lagos adjacentes, no município de Barcelos, AM, Brasil. Seis anéis de crescimento foram identificados nas escamas de C. temensis. A variação anual observada no fator de condição sugere que o acúmulo de gordura ocorreu durante o período de seca. Os resultados de IGS (índice gonadossomático) indicaram que o pico da reprodução ocorreu no período da vazante e que a espécie teve um déficit de energia em seu organismo, devido à atividade reprodutiva. Análise do IMR (incremento marginal relativo) mostrou que há formação de anel uma vez por ano, no período da vazante. Os parâmetros populacionais estimados para C. temensis foram: L50 (comprimento da maturidade sexual) = 31,11 cm; L∞ (comprimento assintótico) = 68,05 cm; k (coeficiente de crescimento) = 0,20.ano-1 e A0,95 ( longevidade ) = 14 anos. Nossos resultados confirmaram a validade do uso das marcas de crescimento, em escamas, para estudo de crescimento de Cichla temensis, como indicadoras da idade e do ritmo de crescimento dessa espécie na região do médio rio Negro.(AU)

Eletrofisiologia ocular em felinos domésticos: eletrorretinografia de campo total e potencial visual evocado por flash de luz

O objetivo deste trabalho foi padronizar o eletrorretinograma de campo total em protocolo curto (ERGpc), o flicker e o potencial evocado por flash de luz (PVE-F) em gatos acordados, além de correlacionar as ondas do PVE-F de paciente sadios com os que apresentavam sintomatologia de síndrome da disfunção cognitiva felina (SDC). Foram selecionados 17 animais, machos e fêmeas, de idades variadas e submetidos a dois momentos de avalição (M1 e M2). No M1 era realizada a avaliação clínica e oftálmica, além de colheita de sangue para hemograma, glicemia, perfil renal, hepático e teste comercial de FiV e FeLV. No M2 eram realizados o ERGpc, o flicker e o PVE-F, um olho de cada vez. Utilizou-se o sistema da Nihon Kohdem, Neuropack 2 MEB-7102A/k, com o sinal digitalizado pelo DATAQ® DI-158U através de um cabo RS232 com três canais e acoplado a um notebook Acer Aspire 4732Z-4620. O primeiro exame realizado foi o PVE-F onde os eletrodos foram dispostos na seguinte sequência: o terra (Fpz) na articulação frontonasal, o (Oz) cranial a crista sargital externa e o referência (Cz) na meia distância entre eles. Ao final do PVE-F o ERGpc foi registrado mediante a instilação de duas gotas de colírio a base de tropicamida, com intervalo de 5 minutos entre cada. Na sequência o paciente era mantido em sala escura para adaptação por 20 minutos, quando era realizada a fase fotópica. Após esse período eram posicionados os eletrodos em duas colocações monopolares, sendo um a 0,5 cm da comissura temporal (referência) e outro na parte caudal da região cervical (terra), foram usados eletrodos subdérmicos da Ambu® modelo Neuroline subdermal 12x0.40mm. Para a colocação do eletrodo corneal monopolar ativo modelo ERG-jet, foi instilada uma gota de colírio de proximetacaína seguido de metilcelulose 1%.No que diz respeito a padronização do ERG percebeu-se que não houve significância estatística entre as faixas etárias. Quanto ao PVE-F verificou-se quatro pontos positivos e negativos (N1, P1, N2, P2, N3, P3, N4 e P4). NoG1b foi marcante a ausência da formação das ondas P2, N3 e P3 para ambos os olhos (5/7 pacientes). No grupo com sinais de SDC observou-se que o maior tempo implícito foi em P2 para ambos os olhos (OD 28,95 e OE 30,6). A amplitudes se mostraram reduzidas com significância estatística.Frente ao exposto concluímos que o ERG em protocolo curto, de modo fotóptico, e o flicker podem ser realizados sem o uso de anestesia ou sedação em qualquer faixa etária e que o PVE-F uma vez reconhecidas ou descartadas as afecções com sintomatologia semelhante a Síndrome da disfunção cognitiva (SDC)pode ser uma ferramenta útil no diagnóstico desta afecção

The aim of this study was to standardize the total short-field electroretinogram(ERGpc), flicker and light-evoked potential (PVE-F) in awake cats, as well as to correlate healthy patient PVE-F waves with those with symptoms of feline cognitive dysfunction syndrome (CKD). We selected 17 male and female animals of different ages and submitted to two moments of evaluation (M1 and M2). Clinical and ophthalmic evaluation was performed in M1, as well was collected a blood sampling for hemogram, blood glucose, renal and hepatic profiles, and commercial test of FiV and FeLV. In M2 moment, ERGpc, flicker and PVE-F were performed in one eye at a time. The Nihon Kohdem system, Neuropack 2 MEB-7102A / k, was used with the signal scanned by the DATAQ® DI-158U through a three-channel RS232 cable and attached to an Acer Aspire 4732Z-4620 notebook. The first test was the PVE-F where the electrodes were arranged in the following sequence: the ground (Fpz) was placed in the frontonasal joint, the cranial (O2) into the external sargital crest and the reference (Cz) in the middle distance between them. At the end of PVE-F, ERGpc was recorded by instillation of two tropicamide-based eye drops, with a 5 minute interval each other. The patient was then kept in the dark room for 20 minutes adaptation, when the photopic phase was performed. After this period, the electrodes were placed in two monopolar positions, one being 0.5 cm from the temporal commissure (reference) and the other at the caudal part of the cervical region ground, were used Neuroline subdermal 12x0.40mm subcutaneous electrodes of the Ambu® model . For placement of active monopolar corneal electrode ERG-jet model, a drop of proximetacaine eye drops followed by 1% methylcellulose was instilled. Regarding the standardization of ERG, there was no statistically significant differences it was noticed that there was no statistical significance between the age groups. As for PVE-F, there were four positive and negative points (N1, P1, N2, P2, N3, P3, N4 and P4). In G1b, the absence of P2, N3 and P3 waves formation was remarkable for both eyes (5/7 patients). In the group with SDC signals it was observed that the greatest implicit time was in P2 for both eyes (OD 28.95 and OE 30.6). Amplitude reduction reached statistical significance. Conclude that ERG in a short protocol, photopically and the flicker can be performed without the use of anesthesia or sedation in any age group and that the PVE-F once recognized or discarded the affections with Syndrome-like symptomatology of cognitive dysfunction (CKD) it may be a useful diagnostic tool.

LOCALIZAÇÃO DA Na+, K+-ATPase EM ESPERMATOZOIDES OVINO IN NATURA, PÓS-DESCONGELAÇÃO E CAPACITADOS IN VITRO E DETERMINAÇÃO DOS EFEITOS DE SEU BLOQUEIO SOBRE AS CARACTERÍSTICAS ESPERMÁTICAS GARANHUNS 2018

Objetivando-se localizar a Na+, K+-ATPase em espermatozoides ovinos (in natura, pós decongelação e capacitados in vitro), assim como avaliar a influência da adição da ouabaína sobre os parâmetros cinemáticos espermáticos, foram realizados dois experimentos. Exp.1: amostras de sêmen (quatro carneiros, sete repetições) foram colhidas, diluídas (Trisgema, concentração final de 200 x 106 espermatozoides/mL) e congeladas à -196 C°. Exp. 2: amostras seminais de quatro ovinos (cinco repetições) foram diluídas em meio TALPm (50 x106 espermatozoides/mL) e aliquotadas em dois grupos: parte destinada a capacitação in vitro (adição de 2,5% de soro de ovelha em estro - SOE) ou com adição de ouabaína (10-4 M), visando o bloqueio da Na+,K+-ATPase. Alíquotas de sêmen de ambos os experimentos foram avaliadas pelo sistema CASA para análise dos parâmetros de cinemética espermática, e por meio da citometria de fluxo, para a localização da Na+, K+-ATPase (Bodipy FL Ouabaína), análise da integridade de membrana plasmática (IP) e acrossomal (FITC-PNA), viabilidade e estabilidade de membrana plasmática (YO-PRO e M540). No Exp. 2, além das análises supracitadas realizou-se também a avaliação do potencial de membrana mitocondrial (JC-1). Para o Exp. 2, todas as análises foram efetudas após 0h e 3h de incubação a 36 °C. Os resultados obtidos foram: 1) a Na+, K+-ATPase foi localizada na peça intermediária dos espermatozoides independente do status da amostra (in natura, pós descongelação e capacitados); 2) o processo de congelação/descongelação resultou em uma diminuição (P<0,05) nos parâmetros de MT, MP e VAP, um aumento no BCF, além de redução (P<0,05) no percentual de células apresentando marcação com Bodipy FL Ouabaína, com membranas plasmáticas e acrossomal íntegras, e percentagem de células com membrana plasmática estabilizada; 3) A longo do período de incubação, o bloqueio da Na+, K+-ATPase resultou na redução (P<0,05) da MP, VCL e VSL, enquanto no grupo controle observou-se redução (P <0,05) dos parâmetros MT, VCL e ALH; 4) A adição do SOE ao meio de TALPm resultou em redução (P<0,05) em MP, VCL e ALH, enquanto no grupo controle reduziu (P<0,05) os valores de MT e MP, não havendo diferença entre tratamentos para os parâmentros cinemáticos. Além disso, independentemente dos tratamentos, observou-se ao longo da incubação elevação (P<0,05) no percentual de células apresentando membrana plasmática lesionadas, acrossomal íntegra sem marcação da Na+, K+-ATPase. Em conclusão, independente do status fisiológico, a Na+, K+-ATPase não alterou sua localização, permanecendo na peça intermediária dos espermatozoides ovinos, e que, sua inibição não influenciou sobre os parâmetros de motilidade espermática.

Aiming to localize the Na+, K+-ATPase in ram sperm (raw, post-thaw and capacitated in vitro), and to evaluate the influience of ouabain addition on kinematic sperm parameters, two experiments were performed. Exp.1: semen samples (four rams, seven replicates) were harvested, diluted (Tris-gema, final concentration 200 x 106 sperm/mL) and frozen at -196 C°. Exp. 2: sêmen samples from four rams (five replicates) were diluted in TALPm (50 x106 sperm/mL) and aliquot for two precedures: in vitro capacitation (addition of 2,5% of estrous sheep serum - ESS) or ouabain addition (10-4 M), in order to block the Na+,K+- ATPase. Semen aliquots from both experiments were evaluated using CASA system for kinematic parameters and with aid of flow cytometry it was determined localization of Na+, K+-ATPase (Bodipy FL Ouabaína), evaluated plasmatic (IP) and acrosomal membrande (FITC-PNA) integrity, viability and stability of sperm plasma membrane (YO-PRO e M540). During Exp. 2, it was also evaluated the mitochondrial membrane potential (JC-1). For Exp. 2, all analysis were performed at 0h and 3h of incubation time (36 °C). These are the results: 1) The Na+, K+-ATPase was localized on middle piece of sperm flagellum, despite sample status (raw, post-thaw and capacitated); 2) the freezing-thawing proccess reduced (P<0,05) MT, MP and VAP and increased BCF. There was also a reduction (P<0.05) on percentage of sperm stained with Bodipy FL Ouabain, with intact plasmatic and acrossomal membranes, and percentage of sperm with stabilized plasma membrane; 3) Throught incubation time, the Na+, K+-ATPase blocking reduced (P<0.05) MP, VCL and VSL, whereas on control group reduced (P <0.05) MT, VCL and ALH; 4) The addition of ESS to TALPm reduced (P<0.05) MP, VCL and ALH, and on control group reduced (P<0.05) MT and MP, with no difference between treatments for kinematic parameters. Therefore, despite of treatment, there was an increasing (P<0.05) on percentage of sperm with damages plasma membrane, intact acrosome and no stain for Na+, K+-ATPase. In conclusion, despit of sperm phisiological status, Na+, K+- ATPase ramains on middle piece of ram sperm flagellum and its inhibition have no influence on sperm motility parameters.

The Cuban scorpion Rhopalurus junceus (Scorpiones, Buthidae): component variations in venom samples collected in different geographical areas

The venom of the Cuban scorpion Rhopalurus junceus is poorly study from the point of view of their components at molecular level and the functions associated. The purpose of this article was to conduct a proteomic analysis of venom components from scorpions collected in different geographical areas of the country. Results Venom from the blue scorpion, as it is called, was collected separately from specimens of five distinct Cuban towns (Moa, La Poa, Limonar, El Chote and Farallones) of the Nipe-Sagua-Baracoa mountain massif and fractionated by high performance liquid chromatography (HPLC); the molecular masses of each fraction were ascertained by mass spectrometry analysis. At least 153 different molecular mass components were identified among the five samples analyzed. Molecular masses varied from 466 to 19755 Da. Scorpion HPLC profiles differed among these different geographical locations and the predominant molecular masses of their components. The most evident differences are in the relative concentration of the venom components. The most abundant components presented molecular weights around 4 kDa, known to be K+-channel specific peptides, and 7 kDa, known to be Na+-channel specific peptides, but with small molecular weight differences. Approximately 30 peptides found in venom samples from the different geographical areas are identical, supporting the idea that they all probably belong to the same species, with some interpopulational variations. Differences were also found in the presence of phospholipase, found in venoms from the Poa area (molecular weights on the order of 14 to 19 kDa). The only ubiquitous enzyme identified in the venoms from all five localities studied (hyaluronidase) presented the same 45 kD molecular mass, identified by gel electrophoresis analysis. Conclusions The venom of these scorpions from different.(AU)

The Cuban scorpion Rhopalurus junceus (Scorpiones, Buthidae): component variations in venom samples collected in different geographical areas

The venom of the Cuban scorpion Rhopalurus junceus is poorly study from the point of view of their components at molecular level and the functions associated. The purpose of this article was to conduct a proteomic analysis of venom components from scorpions collected in different geographical areas of the country. Results Venom from the blue scorpion, as it is called, was collected separately from specimens of five distinct Cuban towns (Moa, La Poa, Limonar, El Chote and Farallones) of the Nipe-Sagua-Baracoa mountain massif and fractionated by high performance liquid chromatography (HPLC); the molecular masses of each fraction were ascertained by mass spectrometry analysis. At least 153 different molecular mass components were identified among the five samples analyzed. Molecular masses varied from 466 to 19755 Da. Scorpion HPLC profiles differed among these different geographical locations and the predominant molecular masses of their components. The most evident differences are in the relative concentration of the venom components. The most abundant components presented molecular weights around 4 kDa, known to be K+-channel specific peptides, and 7 kDa, known to be Na+-channel specific peptides, but with small molecular weight differences. Approximately 30 peptides found in venom samples from the different geographical areas are identical, supporting the idea that they all probably belong to the same species, with some interpopulational variations. Differences were also found in the presence of phospholipase, found in venoms from the Poa area (molecular weights on the order of 14 to 19 kDa). The only ubiquitous enzyme identified in the venoms from all five localities studied (hyaluronidase) presented the same 45 kD molecular mass, identified by gel electrophoresis analysis. Conclusions The venom of these scorpions from different.

Reproductive biology of Sciades herzbergii (Siluriformes: Ariidae) in a tropical estuary in Brazil

The present study investigated the reproductive biology of Sciades herzbergii in the Paraíba do Norte River Estuary, Brazil. We aimed to characterize the reproduction of the species with respect to sex ratio, spawning season, condition factor and length at first maturity. Specimens were captured between August 2009 and July 2010 in a stretch of the main channel of the estuary. In the laboratory, they were measured, weighed and macroscopically classified with regard to sex and gonad development stage, and their gonads were weighted. The monthly distribution of the sexes and their respective stages of maturation were determined. The gonadosomatic index (GSI), condition factor (K) and the length at first maturity were calculated for males and females. The sex ratio was determined monthly and throughout the entire study period and the chi-square test was used to evaluate if the sex ratio differed from 1:1. The Pearson's correlation test was used to determine the correlation between GSI and K values. A total of 260 individuals were captured. It was impossible to determine the sex of 32 individuals, possibly due to their young age. The sex ratio did not differ throughout the overall study period, but significant differences were found in December and May, with a predominance of females, and in March, when males predominated. Spawning activities were concentrated between December and March, as determined by the greater incidence of mature females and higher GSI values. The spawning of the S. herzbergii population is characterized as staggered due to its long duration. For females, K values were not significantly correlated with the GSI, but the decrease in K values in the spawning period indicates that energy is being spent in reproduction. With regard to males, the distribution of developmental stages did not follow the same clear pattern as that seen with females. However, the GSI indicated a greater investment in gonads in October, with a decrease up to July (end of the data acquisition period). For males, K values exhibited a positive correlation with GSI, with a gradual decrease beginning in February up to July, indicating energy that energy was being consumed, which was certainly related to the mouth brooding of eggs and neonates. Mean length at first maturity was 212 mm for females and 240 mm for males. Sciades herzbergii completes its lifecycle in the estuary and exhibits post-spawning parental care. This species is abundant in the estuary studied and information on the reproductive biology of this resident is necessary to the management of the estuarine environment.

Reproductive biology of Sciades herzbergii (Siluriformes: Ariidae) in a tropical estuary in Brazil

The present study investigated the reproductive biology of Sciades herzbergii in the Paraíba do Norte River Estuary, Brazil. We aimed to characterize the reproduction of the species with respect to sex ratio, spawning season, condition factor and length at first maturity. Specimens were captured between August 2009 and July 2010 in a stretch of the main channel of the estuary. In the laboratory, they were measured, weighed and macroscopically classified with regard to sex and gonad development stage, and their gonads were weighted. The monthly distribution of the sexes and their respective stages of maturation were determined. The gonadosomatic index (GSI), condition factor (K) and the length at first maturity were calculated for males and females. The sex ratio was determined monthly and throughout the entire study period and the chi-square test was used to evaluate if the sex ratio differed from 1:1. The Pearson's correlation test was used to determine the correlation between GSI and K values. A total of 260 individuals were captured. It was impossible to determine the sex of 32 individuals, possibly due to their young age. The sex ratio did not differ throughout the overall study period, but significant differences were found in December and May, with a predominance of females, and in March, when males predominated. Spawning activities were concentrated between December and March, as determined by the greater incidence of mature females and higher GSI values. The spawning of the S. herzbergii population is characterized as staggered due to its long duration. For females, K values were not significantly correlated with the GSI, but the decrease in K values in the spawning period indicates that energy is being spent in reproduction. With regard to males, the distribution of developmental stages did not follow the same clear pattern as that seen with females. However, the GSI indicated a greater investment in gonads in October, with a decrease up to July (end of the data acquisition period). For males, K values exhibited a positive correlation with GSI, with a gradual decrease beginning in February up to July, indicating energy that energy was being consumed, which was certainly related to the mouth brooding of eggs and neonates. Mean length at first maturity was 212 mm for females and 240 mm for males. Sciades herzbergii completes its lifecycle in the estuary and exhibits post-spawning parental care. This species is abundant in the estuary studied and information on the reproductive biology of this resident is necessary to the management of the estuarine environment.

Reproductive biology of Sciades herzbergii (Siluriformes: Ariidae) in a tropical estuary in Brazil

The present study investigated the reproductive biology of Sciades herzbergii in the Paraíba do Norte River Estuary, Brazil. We aimed to characterize the reproduction of the species with respect to sex ratio, spawning season, condition factor and length at first maturity. Specimens were captured between August 2009 and July 2010 in a stretch of the main channel of the estuary. In the laboratory, they were measured, weighed and macroscopically classified with regard to sex and gonad development stage, and their gonads were weighted. The monthly distribution of the sexes and their respective stages of maturation were determined. The gonadosomatic index (GSI), condition factor (K) and the length at first maturity were calculated for males and females. The sex ratio was determined monthly and throughout the entire study period and the chi-square test was used to evaluate if the sex ratio differed from 1:1. The Pearson's correlation test was used to determine the correlation between GSI and K values. A total of 260 individuals were captured. It was impossible to determine the sex of 32 individuals, possibly due to their young age. The sex ratio did not differ throughout the overall study period, but significant differences were found in December and May, with a predominance of females, and in March, when males predominated. Spawning activities were concentrated between December and March, as determined by the greater incidence of mature females and higher GSI values. The spawning of the S. herzbergii population is characterized as staggered due to its long duration. For females, K values were not significantly correlated with the GSI, but the decrease in K values in the spawning period indicates that energy is being spent in reproduction. With regard to males, the distribution of developmental stages did not follow the same clear pattern as that seen with females. However, the GSI indicated a greater investment in gonads in October, with a decrease up to July (end of the data acquisition period). For males, K values exhibited a positive correlation with GSI, with a gradual decrease beginning in February up to July, indicating energy that energy was being consumed, which was certainly related to the mouth brooding of eggs and neonates. Mean length at first maturity was 212 mm for females and 240 mm for males. Sciades herzbergii completes its lifecycle in the estuary and exhibits post-spawning parental care. This species is abundant in the estuary studied and information on the reproductive biology of this resident is necessary to the management of the estuarine environment.

Plasma ion levels of freshwater and marine/estuarine teleosts from Southern Brazil

The purpose of this study was to investigate Na+, Cl-, K+, Ca2+, and Mg2+ levels in the plasma of freshwater and marine/estuarine teleosts collected at different salinities (0 to 34) from the estuarine and freshwater portions of the São Gonçalo channel in Southern Brazil. Any relationship between plasma ion levels and salinity and the capacity of ionic regulation of teleosts found at three or more different salinities (Genidens barbus and Micropogonias furnieri) was also investigated. Results showed no relationship between plasma ion levels and salinity when considering all species together, but the two species collected from three or more different salinities showed a significant positive relationship between plasma ion levels and salinity, indicating that G. barbus and M. furnieri have a high capacity to regulate plasma ion levels at both low and high salinities.(AU)

A proposta deste estudo foi investigar os níveis de Na+, Cl-, K+, Ca2+, and Mg2+ no plasma de teleósteos de água doce e marinhos/estuarinos coletados em diferentes salinidades (0 a 34) nas porções de água doce e estuarinas do Canal São Gonçalo, sul do Brasil. Uma possível relação entre os níveis iônicos plasmáticos e a salinidade também foi investigada bem como a capacidade de regulação iônica dos teleósteos coletados em três ou mais salinidades (Genidens barbus e Micropogonias furnieri). Os resultados mostraram que não houve relação entre os níveis iônicos no plasma com a salinidade quando considerando todas as espécies juntas, mas as duas espécies coletadas em três ou mais salinidades mostraram uma relação significativamente positiva entre níveis iônicos no plasma e salinidade, mostrando que G. barbus e M. furnieri apresentaram uma grande capacidade para regular os íons do plasma em baixas e altas salinidades.(AU)

Características químicas de solos de várzeas sob diferentes sistemas de uso da terra, na calha dos rios baixo Solimões e médio Amazonas

The Solimoes/Amazonas River channel high and low land floodplain soils were studied on Manacapuru, Iranduba, Itacoatiara and Silves townships, with purpose the evaluate the chemical characteristics of floodplain soils, as well as, the effect of land use system on soil nutrient status. Nineteen different systems were sampled, eight in the low Solimões river and eleven in medium Amazonas river. Sampling was performed on 0-10, 10-20 and 20-40 cm deep upper soil layers. Contents of pH, Al, Ca, Mg, K, P, C, N, Zn, Cu, Mn, and Fe, were determined. All the land use shows high available of Ca, Mg, P, Zn, Cu, Mn e Fe. Despite the majority soil samples presented high contents of K, the secondary forest and agroforestry systems presented medium content of K, demonstrated this nutrient can be deficient in some systems in the floodplain soils. The systems of forest and secondary forest presented more acidity and higher available Al, contracting with the others systems land use. C and N levels were lower confirming N to be one of the main limiting factors on the farming yield in the Amazonian floodplains.

Foram estudados os solos de várzea alta e baixa em quatro municípios situados na calha dos rios baixo Solimões e médio Amazonas (Manacapuru, Iranduba, Itacoatiara e Silves), com o objetivo de avaliar as características químicas dos solos assim como os possíveis efeitos da unidade de paisagem e dos diferentes sistemas de uso da terra sobre o estoque de nutrientes nesses solos. Um total de 19 diferentes sistemas de uso da terra foi amostrado, sendo oito no baixo rio Solimões e onze no médio rio Amazonas. Os solos foram amostrados nas camadas de 0-10, 10-20 e 20-40 cm de profundidade. As determinações efetuadas foram: pH, Al, Ca, Mg, K, P, C, N, Zn, Cu, Mn e Fe. Todos os sistemas de uso da terra amostrados apresentaram uma alta disponibilidade de Ca, Mg, P, Zn, Cu, Mn e Fe. Apesar do elevado teor de K encontrado na maioria das amostras analisadas, as áreas de capoeiras e sítios na região do médio rio Amazonas, apresentaram uma concentração média de K mostrando que esse nutriente em algumas áreas de várzea pode se tornar limitante. Ao contrário dos outros sistemas de cultivo que apresentaram baixas concentrações de Al trocável, os sistemas de floresta e capoeiras apresentaram acidez elevada e valores tóxicos, desse elemento. Na maior parte dos sistemas de uso da terra estudados, os níveis de C e N no solo foram baixos confirmando que o N é um dos principais nutrientes limitantes para a produção agrícola em área de várzea na Amazônia.

Características químicas de solos de várzeas sob diferentes sistemas de uso da terra, na calha dos rios baixo Solimões e médio Amazonas

The Solimoes/Amazonas River channel high and low land floodplain soils were studied on Manacapuru, Iranduba, Itacoatiara and Silves townships, with purpose the evaluate the chemical characteristics of floodplain soils, as well as, the effect of land use system on soil nutrient status. Nineteen different systems were sampled, eight in the low Solimões river and eleven in medium Amazonas river. Sampling was performed on 0-10, 10-20 and 20-40 cm deep upper soil layers. Contents of pH, Al, Ca, Mg, K, P, C, N, Zn, Cu, Mn, and Fe, were determined. All the land use shows high available of Ca, Mg, P, Zn, Cu, Mn e Fe. Despite the majority soil samples presented high contents of K, the secondary forest and agroforestry systems presented medium content of K, demonstrated this nutrient can be deficient in some systems in the floodplain soils. The systems of forest and secondary forest presented more acidity and higher available Al, contracting with the others systems land use. C and N levels were lower confirming N to be one of the main limiting factors on the farming yield in the Amazonian floodplains.

Foram estudados os solos de várzea alta e baixa em quatro municípios situados na calha dos rios baixo Solimões e médio Amazonas (Manacapuru, Iranduba, Itacoatiara e Silves), com o objetivo de avaliar as características químicas dos solos assim como os possíveis efeitos da unidade de paisagem e dos diferentes sistemas de uso da terra sobre o estoque de nutrientes nesses solos. Um total de 19 diferentes sistemas de uso da terra foi amostrado, sendo oito no baixo rio Solimões e onze no médio rio Amazonas. Os solos foram amostrados nas camadas de 0-10, 10-20 e 20-40 cm de profundidade. As determinações efetuadas foram: pH, Al, Ca, Mg, K, P, C, N, Zn, Cu, Mn e Fe. Todos os sistemas de uso da terra amostrados apresentaram uma alta disponibilidade de Ca, Mg, P, Zn, Cu, Mn e Fe. Apesar do elevado teor de K encontrado na maioria das amostras analisadas, as áreas de capoeiras e sítios na região do médio rio Amazonas, apresentaram uma concentração média de K mostrando que esse nutriente em algumas áreas de várzea pode se tornar limitante. Ao contrário dos outros sistemas de cultivo que apresentaram baixas concentrações de Al trocável, os sistemas de floresta e capoeiras apresentaram acidez elevada e valores tóxicos, desse elemento. Na maior parte dos sistemas de uso da terra estudados, os níveis de C e N no solo foram baixos confirmando que o N é um dos principais nutrientes limitantes para a produção agrícola em área de várzea na Amazônia.

A novel Kv1.1 potassium channel blocking toxin from the venom of Palamneus gravimanus (Indian black scorpion)

A peptide toxin was isolated from the venom of Palamneus gravimanus, the Indian black scorpion, to block human Kv1.1 channels expressed in Xenopus laevis oocytes. A 4.5 kD peptide (toxin), as confirmed by SDS-PAGE, was purified to homogeneity by ion exchange chromatography using CM-Sephadex C-25 followed by Sephadex G-50 gel filtration. Palamneus gravimanus toxin (PGT) selectively blocks the human cloned voltage-gated potassium channel hKv1.1 in a two-electrode voltage-clamp (TEVC) technique. The results obtained indicate that the toxin blocks the hKv1.1 channel at a nanomolar concentration range (Ki value of 10 nM) of the peptide to the external side of the cell. The blockage seems to be voltage-dependent. Comparative structure of PGT (a 4.5 kD peptide) with BTK-2 suggests a close relationship; therefore this toxin can be employed to investigate the hKv1.1 channel structure.