Fish defaunation in reservoirs of the Lower Paranapanema River basin, Brazil / Defaunação de peixes em reservatórios do baixo rio Paranapanema, Brasil

Abstract Until now no study has used a defaunation index to quantify the decline of Neotropical freshwater fishes in environments fragmented by dams and reservoirs. So, we applied this index to 143 native fish in five reservoirs in the Lower Paranapanema River, that is situated in one of the Brazilian aquatic environments most impacted by anthropic degradation. Fish species were classified according to their functional groups, which were selected according to the biological characteristics that may reflect in defaunation events. The biggest reservoir in area with more tributaries and forest cover showed lowest defaunation index. The functional groups of fishes more affected by defaunation included species characterized by periphytivores, invertivores and algivores, non-migratory habit, with external fertilization, and parental care. Although reservoirs have different characteristics, this method can be tested in any other hydrographic basin. The results suggested continued conservation efforts to preserve the integrity of tributaries and the native fishes in reservoirs and pointed out the importance of maintaining native vegetation cover and fish restocking programs in the reservoirs with the highest defaunation values. Our finding can be use as the first data source for future studies using this defaunation index.

Resumo Até o momento nenhum estudo utilizou um índice de defaunação para quantificar o declínio de peixes neotropicais de água doce em ambientes fragmentados por barragens e reservatórios. Dessa forma, testamos esse índice em 143 espécies nativas em cinco reservatórios do baixo rio Paranapanema, que está localizado em um dos ambientes aquáticos brasileiros mais impactados pela degradação antrópica. As espécies de peixes foram classificadas de acordo com seus grupos funcionais selecionados de acordo com as características biológicas que podem influenciar nos eventos de defaunação. O maior reservatório em área, com mais tributários e maior cobertura florestal apresentou menor índice de defaunação. Os grupos funcionais mais afetados pela defaunação incluíram espécies caracterizadas por hábito alimentar perifitívoro, invertívoro e algívoro, hábito não migratório, com fertilização externa e cuidado parental. Embora os reservatórios tenham características diferentes, esse método pode ser testado em qualquer outra bacia hidrográfica. Os resultados sugerem esforços contínuos para preservar a integridade dos tributários e dos peixes nativos nos reservatórios e apontam a importância de manter a cobertura vegetal nativa e programas de estocagem nos reservatórios com maiores valores de defaunação. Nossos dados podem ser utilizados como a primeira base de dados para futuros estudos que utilizem o índice de defaunação.

Correlations between morphological fruit types, fruit and seed colors, and functional groups / Correlaciones entre tipos morfológicos de frutos, colores de frutos y semillas y grupos funcionales

Abstract: The associations between morphological fruit types, fruit and seed colors, and functional plant traits: life forms, epiphytism, physiology, nutritional relationships, fruit phenology, and successional stage, were determined for 1,139 plant species from contrasting plant communities. Texture and dehiscence were closely related. Dehiscence is largely associated with dry tissues; indehiscence, however, is an attribute of both dry and fleshy fruits. The number of morphological fruit types was 28 or 55 for Gray's and Spjut's classifications, respectively. Fruits were predominantly dark in color (brown, purple-black, black or green), whilst seeds had both dark and light colors (brown, beige, or black). The most representative associations were mainly found between the more abundant fruit types and the colors most common. Asymmetries in the level of specialization, whereby less common fruit and seed colors tended to be associated with the most common fruit types, were also found. Fleshy fruits showed more variation as regards their coloration, and only drupes and berries showed a tendency towards a specific color: purple-black. The relationships among fruit type and color, seed color, and functional plant traits revealed the following trends: trees produced both fleshy and dry fruits; shrubs produced fleshy fruits; and herbaceous species, dry fruits. Woody species tended to have dark or bright colors, depending on their seed dispersal mechanisms and phylogenetic relations. Epiphytes were associated with dry-dehiscent fruits and brown seeds, and parasitic-hemiparasitic species had predominantly fleshy-indehiscent fruits. Pioneer species were more likely to have dry fruits, whereas fleshy fruits tended to be more frequent in late successional stage species. The C4 species, mostly herbs, had mainly one-seeded dry fruits, but multi-seeded fruits in succulent-CAM species showed morphologically diverse fruit types. Unripe and ripe fruits showed seasonal changes, especially during the rainy-dry transition period for the most abundant morphological fruit types, dry fruits during the dry period and fleshy fruited species was positively associated with the rainy season. All these trends are discussed with regard to their environmental significance and the relationships between fruit morphology, colors and functional groups. .

Resumen: Las asociaciones entre tipos morfológicos de frutos, colores de frutos y semillas y los grupos funcionales de las plantas: formas de vida, epifitismo, fisiología, relaciones nutricionales, fenología de frutos y estado sucesional fueron determinados para 1139 especies de plantas de comunidades contrastantes. La textura y dehiscencia estaban muy relacionadas. Dehiscencia está estrechamente asociada con tejidos secos, pero indehiscencia es un atributo de frutos secos y carnosos. El número de tipos morfológicos de frutos fue 28 y 55 para la clasificación de Gray y Spjut respectivamente. Los frutos fueron predominantemente de colores oscuros (marrón, negro-purpura, negro o verdes), mientras que las semillas tenían colores claros y oscuros (marrón, beige o negro). Las asociaciones más representativas fueron principalmente encontradas entre los tipos de frutos más abundantes y los colores más comunes. También se encontraron asimetrías en los niveles de especialización, donde los colores menos comunes de frutos y semillas estuvieron asociados con los tipos de frutos más comunes. Los frutos carnosos mostraron más variación en su coloración, y solo las drupas y bayas tendieron a colores específicos como negro-purpura. Las relaciones entre tipo de fruto y color, color semilla y rasgos funcionales de las plantas revelaron las siguientes tendencias: arboles producen frutos secos y carnosos; arbustos frutos carnosos y hierbas producen frutos secos. Las especies leñosas tendieron a tener colores oscuros y brillantes, relacionados con su mecanismo de dispersión y filogenia. Epifitas estuvieron asociadas con frutos secos dehiscentes y semillas marrones, y las especies parásitas-hemiparásitas tenían predominantemente frutos carnosos indehiscentes. Las especies pioneras tenían comúnmente frutos secos, mientras que los frutos carnosos tendieron a ser más frecuentes en especies de estados sucesionales tardíos. Las especies C4, principalmente hierbas, tenían frutos secos con una semilla, mientras que frutos polispermos en especies CAM mostraron diversos tipos de frutos. La fenología de frutos maduros e inmaduros mostro cambios estacionales para los más abundantes tipos morfológicos, especialmente durante el periodo de transición lluvia-sequia, frutos secos en el periodo seco y frutos carnosos durante el periodo lluvioso. Todas estas tendencias son discutidas con relación a las características ambientales y de acuerdo con las relaciones entre tipos morfológicos de frutos, colores y grupos funcionales.

Mechanistic insights of the controlled release capacity of polar functional group in transdermal drug delivery system: the relationship of hydrogen bonding strength and controlled release capacity

Background@#Hydrogen bonding interaction was considered to play a critical role in controlling drug release from transdermal patch. However, the quantitative evaluation of hydrogen bonding strength between drug and polar functional group was rarely reported, and the relationship between hydrogen bonding strength and controlled release capacity of pressure sensitive adhesive (PSA) was not well understood. The present study shed light on this relationship.@*Methods@#Acrylate PSAs with amide group were synthesized by a free radical-initiated solution polymerization. Six drugs, , etodolac, ketoprofen, gemfibrozil, zolmitriptan, propranolol and lidocaine, were selected as model drugs. drug release and skin permeation experiments and pharmacokinetic experiment were performed. Partial correlation analysis, fourier-transform infrared spectroscopy and molecular simulation were conducted to provide molecular details of drug-PSA interactions. Mechanical test, rheology study, and modulated differential scanning calorimetry study were performed to scrutinize the free volume and molecular mobility of PSAs.@*Results@#Release rate of all six drugs from amide PSAs decreased with the increase of amide group concentrations; however, only zolmitriptan and propranolol showed decreased skin permeation rate. It was found that drug release was controlled by amide group through hydrogen bonding, and controlled release extent was positively correlated with hydrogen bonding strength.@*Conclusion@#From these results, we concluded that drugs with strong hydrogen bond forming ability and high skin permeation were suitable to use amide PSAs to regulate their release rate from patch.

The Guild Concept: From Feudalism to Community Ecology / El concepto de gremio: del feudalismo a la ecología de comunidades

RESUMEN Se analiza el origen y evolución del término gremio, así como su aplicación en ecología, considerando las múltiples connotaciones que se le ha dado y la confusión que se ha generado por utilizarlo de forma indebida. De igual forma, se discute la importancia de homogenizar los términos y definir de manera clara a los gremios, a fin de tener un leguaje que permita entender los alcances del término sin ambigüedades. El uso del término, así como su persistencia en estudios ecológicos, sugiere que el mismo tiene relevancia considerable dependiendo de la forma y el modo en que es empleado. El uso inadecuado o derivado de este término es arriesgado y peligroso, dado que tiende a reducir el término a una palabra vacía con múltiples significados. Más que nada, esta trivialización constituye una amenaza al uso y significado adecuado del concepto de gremio en ecología.

ABSTRACT The origin and evolution of the term guild are analyzed, as well as its application in ecology, considering the multiple connotations that have been given and the confusion that has been generated by using it improperly. Likewise, the importance of homogenizing the terms and clearly defining the guilds is discussed, to have a language that allows understanding the scope of the term without ambiguities. The use of the term, as well as its persistence in ecological studies, suggests that it has considerable relevance depending on the form and the way it is used. The inappropriate or derivative use of this term is risky and dangerous since it tends to reduce the term to an empty word with multiple meanings. Also, this trivialization constitutes a threat to the proper use of the guild concept in ecology and its meaning as a whole.

Morfología funcional del fitoplancton en un lago de alta montaña tropical: Lago de Tota (Boyacá-Colombia) / Functional morphology of phytoplankton in a tropical high mountain lake: Tota Lake (BoyacáColombia)

ResumenLa morfología funcional corresponde a las respuestas de adaptación a los cambios en el medio ambiente. En fitoplancton, rasgos como el desarrollo de mucílago, vesículas de aceite, filamentos y variación en la relación superficie/ volumen, permiten enfrentar la sedimentación, optimizar la captación lumínica y de nutrientes. El objetivo del presente estudio fue evaluar la relación entre los rasgos y la variación de las condiciones físicas y químicas en el lago de Tota (Boyacá, Colombia). Para esto, se realizaron diez muestreos mensuales entre octubre 2013 y julio 2014. Se midieron el pH, conductividad eléctrica, temperatura, oxígeno disuelto, saturación de oxígeno, alcalinidad y dureza total del agua. Además se recolectaron muestras para la cuantificación en laboratorio de Nitrógeno Total Kjeldahl y Fósforo Total. Las algas se obtuvieron en diferentes profundidades según la transparencia Secchi. Se caracterizó la composición taxonómica y se estimó la abundancia por el método de sedimentación en cámaras. Se midieron los rasgos morfológicos de cada taxa según la correspondencia a modelos geométricos, se clasificaron en grupos funcionales basados en morfología (GFBM) y se calculó su biomasa expresada como biovolumen. Las variables fueron evaluadas mediante Análisis de Componentes Principales, que incluyó el efecto espacio-temporal y fue interpretado según la variación en el nivel del agua. Mediante Análisis de Correspondencia Canónica se estableció la relación entre el biovolumen del fitoplancton acumulado en categorías de forma y las variables ambientales. La ordenación mostró que las condiciones limnológicas son influenciadas por cambios estacionales, principalmente representadas por el porcentaje de saturación de oxígeno, la transparencia Secchi, el NTK, la dureza y la alcalinidad. Se encontraron cuatro GFBM: IV, V, VI y VII, siendo los GFBM IV y VII, los más representativos. El ACC fue significativo (Test de Monte-Carlo, p<0.05). En conclusión, la respuesta morfológica y funcional del fitoplancton del lago de Tota esta condicionada principalmente por la variabilidad a corto plazo, en la transparencia, el fósforo, el nitrógeno, la dureza y la conductividad eléctrica, que son afectados por los cambios estacionales en el nivel del lago.

AbstractFunctional morphology corresponds to adaptive responses to changes in the environment. In phytoplankton, traits such as the development of mucilage, oil vesicles, filaments and variation in the surface/volume ratio, allow algae to deal with sedimentation, optimizing light and nutrient uptake. The aim of this research was to evaluate the relationship between traits and variation in physical and chemical conditions in Tota Lake (Boyacá, Colombia). For this, ten samplings were undertaken in a monthly basis between October 2013 and July 2014. We measured water pH, conductivity, temperature, dissolved oxygen, oxygen saturation, alkalinity and total hardness; we also quantified Total Kjeldahl nitrogen and Total phosphorus. Algae were collected at different depths according to Secchi transparency. Taxonomic composition and abundance were estimated by the chamber sedimentation method. Morphological traits were measured for each taxa according to geometric models, allowing traits classification into morphologically based functional groups (MBFG) and having algae biomass expressed as biovolume. The variables were evaluated through Principal Components Analysis, which included time-space effect and it was interpreted according to variation in water level. Through Canonical Correspondence Analysis we established the relationship between phytoplankton biovolume accumulated in form categories and environmental variables. The ordination showed that limnological conditions are influenced by seasonal changes, which are mainly represented by oxygen saturation percentage, Secchi transparency, TKN, hardness and alkalinity. Four MBFG were found: IV, V, VI and VII, being MBFG IV and VII the most representatives. ACC was significant (Monte-Carlo Test, p<0.05). In conclusion, the morphological and functional response of phytoplankton in Tota Lake is driven by short-term variability in transparency, phosphorus, nitrogen, hardness, and electrical conductivity, which are all affected by seasonal changes in the lake level.

Influences different functional groups on the biological characteristics of the osteosarcoma Saos-2 cell line / 医学研究生学报

Objective Microenvironment plays important roles in the proliferation , viability, and apoptosis of tumor cells. This study was to investigate the effects of different functional groups on the biological characteristics of the osteosarcoma Saos -2 cell line in vitro. Methods Using self-assembled monolayers of alkanethiols on gold , we prepared different terminal chemical groups , including methyl (-CH3 ) , amino (-NH2 ) , hydroxyl (-OH) , and carboxyl (-COOH ) .We determined the similar density of different functional groups by contact angle measurement and x-ray photoelectron spectroscopy , and observed the effects of different functional groups on the adhesion , proliferation, viability, and apoptosis of the osteosarcoma Saos-2 cells by fluorescence microscopy , CCK-8 as-say, flow cytometry, and scan electron microscopy (SEM). Results The surface of -COOH and -NH2 promoted the adhesion and proliferation of the of the Saos-2 cells, with a good compatibility , while that of -CH3 was unfavorable for their adhesion and proliferation and even increased their apoptosis . The promoting effects of the functional groups on the adhesion and proliferation of the cells were listed in the following order: -COOH ≥ -NH2 >-OH -CH3 , while their toxicity and apoptosis-increasing effect ranked as -CH3 -OH >-NH2 >-COOH. Conclusion The-CH3 group inhibits the adhesion and proliferation and promotes the apoptosis of Saos-2 cells, which has provided some evidence for the surface design of biomaterials.

Impacts of Tetrakis-hydroxymethyl Phosphonium Sulfate (THPS) Based Biocides on the Functional Group Activities of Some Oil Field Microorganisms Associated with Corrosion and Souring.

Aim: To determine the biocidal efficacy of THPS based biocides currently used in oil fields to control souring and corrosion. Methodology: By direct monitoring of inhibition of cell growth and inhibition of microbial functional group activities such as the ability to reduce sulfate and generate sulfide by sulfate reducing bacteria (SRB), reduce nitrate to nitrite by heterotrophic nitrate reducing bacteria (hNRB) and oxidation of sulfide and reduction of nitrate by sulfide oxidizing, nitrate reducing bacteria( so-NRB) using CSB-K medium. Results: We observed that higher doses of THPS (>400 ppm) was required to considerably inhibit the ability of SRB to reduce sulfate and generate hydrogen sulfide. It was also observed that the activities of SRB were more affected by the THPS biocides than those of hNRB and so-NRB. Conclusion: We conclude that SRB may have developed low level microbial resistance to THPS based biocides as higher doses are required to inhibit their activities. It is therefore recommended that THPS should be used in combination with other biocides or metabolic inhibitors for it to be effective at lower concentrations.

The level of Inhibition of Microbial Functional Group Activities by Some Oxidizing Agents Commonly used as Biocides in Oil field Operations.

Aim: To determine the level of inhibition of microbial functional group activities such as the ability to reduce sulfate to sulfide by sulfate reducing bacteria (SRB), reduce nitrate to nitrite by the heterotrophic nitrate reducing bacteria (hNRB), and oxidize sulfide and reduce nitrate by sulfide oxidizing, nitrate reducing bacteria (so-NRB) by some oxidizing biocides like chlorine, bromine and ozone. Methodology: Samples of the oxidizing biocides were obtained from Microcheck and the inhibition of some functional group activities in produced and injection water samples were determined using CSB-K medium. Results: Ozone was found to be more effective than chlorine and bromine in the inhibition of functional group activities at lower concentrations. Conclusion: More research effort is required to see if ozone can work in synergy with other biocides to improve on its efficiency.

Seasonal dynamics of phytoplankton in two tropical rivers of varying size and human impact in Southeast Nigeria / Dinamica de temporada del fitoplankton en dos rios tropicales de tamaño e impacto humano variado en el sureste de Nigeria

Phytoplankton occurrence and dynamics in rivers are mainly shaped by hydrophysical conditions and nutrient availability. Phytoplankton main structuring factors have been poorly studied in West African rivers, and this study was undertaken to identify these conditions in two tropical rivers that vary in size and human impact. For this, environmental variables and phytoplankton monthly samples were collected from the middle reaches of Asu and Cross rivers during an 18 months survey from March 2005-July 2006. Phytoplankton biomass (F=11.87, p=0.003), Shannon-Weiner diversity and species richness (F=5.93, p=0.003) showed significant seasonality in Asu but not in Cross River. Data was analyzed with Canonical correspondence analysis (CCA) and showed environmental differences between the two rivers, nitrate in Asu River (5.1-15.5mg/L) was significantly higher than Cross River (0.03-1.7mg/L), while PO4 (0.2-0.9mg/L) was significantly lower in Asu River compared to Cross River (0.03-2.6mg/L) (p<0.05). Eutrophic factors (NO3) determined primarily phytoplankton dynamics in Asu River, especially during the dry season, whereas hydrophysical factors (depth, transparency and temperature) shaped phytoplankton in Cross River. Taxa indicative of an eutrophic condition, such as Euglena, Chlorella, Chlorococcus, Ceratium, Peridinium, Anabaena, Aphanizomenon, Closterium, Scenedesmus and Pediastrum spp., were frequently encountered in the shallow impounded Asu River, while riverine species, such as Frustulia rhomboids, Gyrosigma sp., Opephora martyr and Surirella splendida dominated Cross River. A succession pattern was observed in the functional groups identified: Na/MP→TB→P (rainy→dry season) was observed in Asu River, whereas MP/D predominated in Cross River for both seasons. We concluded that, if nutrients predominate hydrophysical factors in shaping phytoplankton during dry season (half of the year) then, they are as important as hydrophysical factors structuring phytoplankton during rainy season (the other half).

La existencia del fitoplancton y la dinámica de los ríos están principalmente determinados por condiciones hidrofísica y disponibilidad de nutrientes. Los principales factores de estructuración del fitoplancton han sido poco estudiados en los ríos de Africa Occidental, y este estudio fue realizado para identificar estas condiciones en dos ríos tropicales que varían en tamaño e impacto humano. Para ello, variables ambientales y muestras ambientales mensuales de fitoplancton se obtuvieron de la parte media de los ríos Asu y Cross durante un estudio de 18 meses, de Marzo-2005 a Julio-2006. La biomasa del fitoplancton (F=11.87, p=0.003), el índice de diversidad de Shannon-Weiner y la riqueza de especies (F=5.93, p=0.003), mostraron estacionalidad significativa en Asu pero no el río Cross. Los datos fueron analizados con el análisis de correspondencia canónica (CCA) y mostró diferencias ambientales entre los dos ríos, el nitrato en el río Asu (5.1-15.5mg/L) fue significativamente mayor que en el río Cross (0.03-1.7mg/L), mientras que PO4 (0.2-0.9mg/L) fue significativamente menor en el río Asu en comparación al río Cross (0.03-2.6mg/L) (p<0.05). Los factores eutróficos (NO3) determinaron principalmente la dinámica del fitplancton en el río Asu, especialmente durante la estación seca, mientras que los factores hidrofísicos (profunidad, transparencia y temperatura) conformaron el fitoplancton en el río Cross. Taxones indicadores de una condición eutrófica, como Euglena, Chlorella, Chlorococcus, Ceratium, Peridinium, Anabaena, Aphanizomenon, Closterium, Scenedesmus y Pediastrum spp fueron frecuentemente encontradas en las aguas poco profundas del río Asu, mientras que las especies fluviales, como Frustulia rhomboids, Gyrosigma sp., Opephora martyr y Surirella splendida dominaron el río Cross. Un patrón de sucesión se observó en los grupos funcionales, identificados: Na/MP→TB→P (Estacion lluviosa → estación seca), fue observado en el río Asu, mientras que MP/D predominó en el río Cross para ambas estaciones. Se concluyó que, si los nutrientes predominan los factores hidrofísicos en la conformación del fitoplancton durante la estación seca (la mitad del año), entonces, son tan importantes como los factores hidrofísicos estructurales del fitoplancton durante la temporada de lluvias (la otra mitad).

Spatial and temporal fluctuation of phytoplankton functional groups in a tropical reservoir / Variação espacial e temporal dos grupos funcionais do fitoplâncton em um reservatório tropical

Along the horizontal axis of reservoirs are generally recognized three zones (fluvial, transition and lacustrine) with distinct hydrodynamic and physical, chemical and biological properties. Quarterly samplings were conducted in 2002, in the limnetic region from each zone, at different depths of a tropical reservoir. To test the hypothesis that highest biomass (biovolume) of phytoplankton are found in the transition zone, the PERMANOVA analysis was realized. 106 taxa were recorded. Significant differences between biovolume values of the three zones were not verified (pseudo F = 0,89; p = 0,55). Higher values of biomass were obtained in lacustrine and transition zones of the reservoir. The functional group (FG) N (Cosmarium spp.) was dominant in these zones, in rain period, and related to low phosphorus concentration, high transparency and water column stability. Low biovolume values in reservoir characterized oligotrophic conditions in all zones of the reservoir, most of the period. The dominance of FGs Y, Lo, E, P and A, as evidenced by the CCA, was associated with low light availability and higher nutrients concentrations.

Ao longo do eixo horizontal de reservatórios são, em geral, reconhecidas três zonas (fluvial, transição e lacustre) com distinta hidrodinâmica e propriedades físicas, químicas e biológicas. Foram realizadas amostragens trimestrais no ano de 2002, na região limnética de cada zona, em diferentes profundidades, em um reservatório tropical. Para testar a hipótese de que os maiores valores de biovolume fitoplanctônico ocorrem na zona de transição do reservatório, foi realizada a Análise PERMANOVA. Foram registrados 106 táxons. Não foram registradas diferenças significativas entre os valores de biovolume fitoplanctônico das zonas do reservatório (pseudo F = 0,89; p= 0,55). Maiores valores de biovolume foram obtidos na zona lacustre e na zona de transição do reservatório. O grupo funcional N (Cosmarium spp.), dominante nestas zonas, no período chuvoso, esteve relacionado às baixas concentrações de fósforo, alta transparência e estabilidade da coluna de água. Os baixos valores de biovolume caracterizaram condições oligotróficas em todo o reservatório, na maior parte do período de estudo. A dominância dos FGs Y, Lo, E, P e A, como evidenciado por meio da CCA, esteve associada à baixa disponibilidade de luz e concentrações mais altas de nutrientes.

A descrição matemática do processo da detecção de duas substâncias com um grupo funcional comum pelos sensores e biossensores eletroquímicos baseados nos polímeros condutores / The mathematical description for the process of the detection of two substances with a common functional group by cp-based sensors and biosensors

O comportamento dos sensores e biossensores eletroquímicos, baseados nos polímeros condutores (pc), no processo da detecção de duas substâncias com um grupo funcional comum foi matematicamente descrito, sendo o respectivo modelo analisado por meio da teoria de estabilidade linear e da análise de bifurcações. Foram inferidas as condições de estabilidade do estado estacionário, como também das instabilidades oscilatória e monotônica. Também foi demonstrada a ligação entre este modelo e os descritos anteriormente.

The behavior of the electrochemical sensors and biosensors, based on conducting polymers (cp) in the detection process for two substances with a common functional group has been described mathematically and the respective model was analyzed by the linear stability theory and bifurcational analysis. The conditions for the stability of the steady-state, for the oscillatory and monotonic instability have been inferred. The connection between the present model and the yet described has been shown.

Trophic organization and fish assemblage structure as disturbance indicators in headwater streams of lower Sorocaba River basin, São Paulo, Brazil

Studies that investigate the relationship patterns between environmental structure complexity and fish fauna provide crucial information to stream restoration efforts. In order to test the hypothesis that streams with more complex environmental structure sustain more diverse and functionally more complex fish communities we sampled fish fauna from Sorocaba River headwater stream reaches (SE - Brazil). Reaches represented two distinct treatments: (1) a simplified reach, characterized by unstable fine substrate, clay, deeper channel and higher water velocity and (2) structurally complex reaches, characterized by coarse substrate, with gravel, pebble, rock, stems and branches and leaves inside the channel, producing a diverse pattern of microhabitat, associated with sequences of pools, runs, and riffles. Both trophic structure and taxonomic composition varied significantly between treatments. Invertivorous trophic group exclusively occurred in structurally complex reaches, which also presented greater diversity and species richness. We suggest enhancing in-stream environmental structure that suffered simplification processes due to human impacts in order to reestablish fish communities and ecossistemic functioning. .

Estudos que buscam investigar os padrões de relação entre a complexidade da estrutura ambiental e a fauna de peixes fornecem informações cruciais para os esforços de restauração de riachos. Para testar a hipótese de que riachos com estrutura ambiental mais complexa sustentam comunidades ícticas mais diversas do ponto de vista taxonômico e funcional, a ictiofauna de trechos de riachos de cabeceira do rio Sorocaba (SE - Brasil) foi amostrada, representando dois tratamentos distintos: (1) um trecho de riacho simplificado, caracterizado por substrato fino e inconsolidado, composto por areia e silte, curso d'água mais profundo, com maior velocidade e poucos elementos diversificadores da estrutura de habitat e (2) trechos de riacho estruturalmente complexos, com substrato de fundo composto por elementos irregulares como cascalho, rochas, seixos, troncos, galhos e restos de madeira, produzindo um padrão diverso de microhabitats, associados à sequências de poços, corredeiras e trechos rápidos. Tanto a estrutura trófica quanto a composição taxonômica foram distintas em relação aos dois tipos de riachos. O grupo trófico dos invertívoros ocorreu somente nos trechos estruturalmente mais complexos, que apresentaram também maior diversidade e riqueza de espécies. Sugere-se incrementar a estrutura ambiental de riachos que sofreram simplificação ambiental, devido à ação humana, a fim de promover a reestruturação da comunidade íctica e o funcionamento ecossistêmico.

Resposta da comunidade de formigas aos atributos dos fragmentos e da vegetação em uma paisagem da Floresta Atlântica nordestina / Response of the ant community to attributes of fragments and vegetation in a northeastern Atlantic Rain Forest area, Brazil

The objective of this study was to determine the effects of forest fragmentation on ant richness in a landscape of Atlantic Forest in Northeast Brazil. More specifically, the ant richness was related to the attributes of fragments (area and distance from the fragment central point to the edge), landscape (forest cover surrounding the fragments), and tree community (plant density, richness, and percentage of shade tolerant species). The surveys were carried out in 19 fragments located in Alagoas State from October 2007 to March 2008. Samples were collected through a 300 m transect established in the center of each fragment, where 30 1-m² leaf litter samples were collected at 10 m intervals. A total of 146 ant species was collected, which belonged to 42 genera, 24 tribes and nine subfamilies. The attributes of fragments and landscape did not influence ant richness. On the other hand, tree density explained ca. 23 percent of ant richness. In relation to functional groups, both density and richness of trees explained the richness of general myrmicines (the whole model explained ca. 42 percent of the variation in this group) and percentage of shade tolerant trees explained the richness of specialist predator ants (30 percent for the whole model). These results indicate that ant fauna is more influenced by vegetation integrity than by fragment size, distance to edge or forest cover surrounding fragments.

Hormigas: relaciones especies-área en fragmentos de bosque seco tropical / Ants: species-area relationship in tropical dry forest fragments

Analizamos el efecto de la fragmentación sobre las relaciones especies-área y frecuencia relativa-área de hormigas en nueve fragmentos de bosque seco tropical en la cuenca media del río Cauca, Colombia. La riqueza y frecuencia relativa total de hormigas se correlacionó positivamente con el área más no con el grado de aislamiento. Como la fragmentación afecta diferencialmente grupos funcionales, se encontró que según el hábitat que ocupan son más afectadas en su orden las especies que viven en troncos en descomposición y la vegetación arbórea, mientras que las especies de hormigas asociadas a la hojarasca, no mostraron relación significativa con el área. Según las preferencias en la obtención de alimento, las especies cazadoras en grupo, mostraron correlación con el área de los fragmentos, mientras que hormigas cazadoras solitarias y cultivadoras de hongos, no se correlacionaron significativamente. En contraste a lo esperado, la densidad de individuos y especies de hormigas, basadas en muestras de igual tamaño, fueron relacionadas con el área, encontrando una relación no significativa para la densidad de especies y una correlación inversa significativa para la densidad de individuos. Según nuestro conocimiento, este es uno de los primeros estudios que muestra respuestas diferenciales de grupos funcionales de hormigas a la pérdida del área, además que se enfatiza el gran valor de los pequeños fragmentos para la conservación de la diversidad de hormigas en el bosque seco tropical.

We analyzed the effect of fragmentation on ant species-area and specimen frequency-area relationships in nine patches of tropical dry forest in the middle Cauca river basin in Colombia. Species richness and specimen relative frequency of ants were positively correlated with area, whereas no significant correlation was found between species richness and the degree of isolation calculated for the forest patches. As the fragmentation affects different functional groups in different ways, we analyzed the species-area relationship for separate functional groups of ants. According to the habitat requirements we found that the species richness increased faster as area increased for ants inhabiting decomposing wood, followed by ants associated with trees, while species richness of ants living under dead leaves did not correlate with area. According to the food preference, species richness was positively correlated with area for the army ant group, while no significant correlation was found for solitary hunters or for leaf-cutting ants. Ant species richness and specimen density were calculated from equal size samples and examined in relation to the habitat area. An inverse correlation was found only for specimen density, the opposite of what was expected. To our knowledge this is one of the first studies showing differential responses of functional groups of ants to habitat loss. Moreover, it emphasizes the conservation value of small forest fragments for ants in a tropical dry forest.

Free Radical Scavenging Action of Volatile Oil from Piper longum L.and Its Relationship with Molecular Structure / 中药新药与临床药理

Objective To observe the free radical scavenging action of volatile oil from Piper longum L.growing in Hainan Province and to explore the relationship of the action with molecular structure.Methods 1,1-Diphenyl-2-picrylhydrazyl radical(DPPH) method was used to determine the scavenging action.The components of volatile oil were analyzed by GC-MS,and their molecular structures were identified by databank.Results(1)The volatile oil from Piper longum L.had scavenging actions on free radicals in a concentration-dependent manner.(2)Forty one compounds were found in volatile oil from Piper longum L.growing in Hainan Province,in which the amount of carbon-carbon double bond(C=C) was in predomination.Conclusion Carbon-carbon double bond(C=C)is the essential functional group for free radical scavenging action of volatile oil from Piper longum L.