Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Mais filtros










Tipo de estudo
Intervalo de ano de publicação
2.
Case Rep Hematol ; 2019: 3914828, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31281685

RESUMO

We present a case of a patient with a three-month history of peripheral blood cytopenia without a confirmed diagnosis of myelodysplastic syndrome, who developed a favourable-risk acute myeloid leukemia (AML), according to the European Leukemia Net (ELN) criteria. The patient achieved a complete remission with incomplete platelet recovery (CRi) after induction. The patient achieved the morphological CR after the first consolidation and completed the first-line treatment with a syngeneic stem cell transplantation (SCT). A disease relapse occurred after one year of CR (blast cell count in the bone marrow 15%), and the patient was offered a haplo-SCT, which he refused due to personal reasons. In this paper, we discuss the interplay between clinical and biological risk factors in non-high-risk AML patients and speculate that some old clinical risk factors (e.g., age of the patient, achievement of CR after induction, and previous history of myelodysplastic syndrome) may still impact on the treatment decision algorithm of some of these patients.

3.
Mar Pollut Bull ; 129(2): 487-493, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29033167

RESUMO

Heavy metals and microplastics have been considered as threats to the marine environment and the interactions between these two pollutants are poorly understood. This study investigates the interactions between metals adsorbed in pellets collected randomly from 19 beaches along the coast of São Paulo State in southeastern Brazil, comparing these levels with those in virgin pellets. The samples were analyzed for Al, Cr, Cu, Fe, Mn, Sn, Ti and Zn by inductively coupled plasma optical emission spectroscopy (ICP-OES). The polymers were solubilized via acid digestion. The highest levels occurred with Fe (227.78mgkg-1 - Itaguaré) and Al (45.27mgkg-1 - Guaraú) in the same areas, which are closer to the Port of Santos. The metal adsorption on pellets collected is greater than that on virgin pellets. In this context, pellets can be considered to be a carrier for the transport of metals in the environment, even in small quantities.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Plásticos/química , Água do Mar/química , Poluentes Químicos da Água/análise , Adsorção , Brasil , Análise Espaço-Temporal
4.
Mar Pollut Bull ; 121(1-2): 154-159, 2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28595982

RESUMO

Microplastics are emergent pollutants in marine environments, whose risks along food-web still need to be understood. Within this knowledge gap, MPs transference and persistence along trophic levels are key processes. We assessed the potential occurrence of these processes considering a less extreme scenario of exposure than used previously, with microplastics present only in the hemolymph of prey (the mussel Perna perna) and absent in the gut cavity. Predators were the crab Callinectes ornatus and the puffer fish Spheoeroides greeleyi. Transference of microplastics occurred from prey to predators but without evidences of particle persistence in their tissues after 10days of exposure. This suggests a reduced likelihood of trophic cascading of particles and, consequently, a reduced risk of direct impacts of microplastics on higher trophic levels. However, the contact with microplastics along food-webs is still concerning, modulated by the concentration of particles in prey and predators' depuration capacity and rate.


Assuntos
Cadeia Alimentar , Plásticos/farmacocinética , Poluentes Químicos da Água/farmacocinética , Animais , Organismos Aquáticos , Perna (Organismo) , Probabilidade
5.
Mar Pollut Bull ; 106(1-2): 183-9, 2016 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-26980138

RESUMO

Microplastic pollution (particles <5mm) is a widespread marine threat and a trigger for biological effects, especially if ingested. The mussel Perna perna, an important food resource, was used as bioindicator to investigate the presence of microplastic pollution on Santos estuary, the most urbanized area of the coast of São Paulo State, Brazil. A simple and rapid assessment showed that 75% of sampled mussels had ingested microplastics, an issue of human and environmental concern. All sampling points had contaminated mussels and this contamination had no clear pattern of distribution along the estuary. This was the first time that microplastic bioavailability was assessed in nature for the southern hemisphere and that wild P. perna was found contaminated with this pollutant. This is an important issue that should be better assessed due to an increase in seafood consumption and culture in Brazil and worldwide.


Assuntos
Monitoramento Ambiental , Plásticos/análise , Poluentes Químicos da Água/análise , Animais , Brasil , Estuários , Perna (Organismo) , Alimentos Marinhos , Frutos do Mar , Urbanização
6.
Mar Pollut Bull ; 92(1-2): 99-104, 2015 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-25662316

RESUMO

Apart from the physiological impacts on marine organisms caused by ingesting microplastics, the toxicity caused by substances leaching from these particles into the environment requires investigation. To understand this potential risk, we evaluated the toxicity of virgin (raw) and beach-stranded plastic pellets to the development of embryos of Lytechinus variegatus, simulating transfers of chemical compounds to interstitial water and water column by assays of pellet-water interface and elutriate, respectively. Both assays showed that virgin pellets had toxic effects, increasing anomalous embryonic development by 58.1% and 66.5%, respectively. The toxicity of stranded pellets was lower than virgin pellets, and was observed only for pellet-water interface assay. These results show that (i) plastic pellets act as a vector of pollutants, especially for plastic additives found on virgin particles; and that (ii) the toxicity of leached chemicals from pellets depends on the exposure pathway and on the environmental compartment in which pellets accumulate.


Assuntos
Desenvolvimento Embrionário/efeitos dos fármacos , Lytechinus/efeitos dos fármacos , Plásticos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Equinodermos , Lytechinus/embriologia , Plásticos/química
7.
Transpl Infect Dis ; 16(5): 697-712, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25040166

RESUMO

BACKGROUND: Bacterial, fungal, and viral infections often affect non-relapse mortality after allogeneic stem cell transplantation (alloSCT). Recovery from infections depends on a balanced integration between innate and adaptive immune responses. In this complex interplay, a key role is played by Toll-like receptors (TLRs), which are sensors of pathogen-associated molecular patterns. To our knowledge, no previous study deals with both expression and function of all human TLRs together, in relation to infections in the setting of alloSCT. METHODS: We prospectively evaluated 9 TLRs by flow cytometry on T lymphocytes and monocytes of 35 patients in relation to infectious events from day +30 to day +120. Tumor necrois factor-alpha, interleukin-4, interferon-gamma, and monocyte chemoattractant protein-1 induction upon TLR activation was assessed by enzyme-linked immunosorbent assay on cell supernatants. RESULTS: In multivariate Cox regression analysis, levels of TLR-9 expression on T lymphocytes (P = 0.01) and values of natural killer cells (P = 0.01) correlated negatively with bacterial infections, whereas cytomegalovirus (CMV) infection resulted as a positive predictor. We observed a trend for negative correlation between TLR-7 levels on T lymphocytes and fungal infections (P = 0.07). Values of monocytes were negatively associated with CMV infection (P = 0.03), whereas levels of TLR-5 on T lymphocytes were positive predictors (P = 0.01). Age (P = 0.03) and bacterial infections (P = 0.006) negatively influenced overall survival. Monocyte values were positive predictors of survival (P = 0.003). CONCLUSIONS: Bacterial, fungal, and CMV infections were associated with a different expression of some TLRs on T lymphocytes. The protective role of TLR-7 and TLR-9 seemed dominant over other TLRs involved in recognizing fungi and bacteria. We also observed an atypical involvement of TLR-5 in CMV infection. The dominant and atypical role of some TLRs could depend on their pleiotropic functions and the changing inflammatory environment of transplanted patients. A specific TLR profile and an adequate count of monocytes could improve survival, promoting an effective control of infections, and balanced immune responses. If our findings will be confirmed by further studies, these immunological variables could be useful as parameters to predict susceptibility to infections.


Assuntos
Células Matadoras Naturais/química , Monócitos/química , Transplante de Células-Tronco/efeitos adversos , Linfócitos T/química , Receptores Toll-Like/análise , Adolescente , Adulto , Fatores Etários , Infecções Bacterianas/imunologia , Células Cultivadas , Quimiocina CCL2/metabolismo , Infecções por Citomegalovirus/imunologia , Feminino , Humanos , Interferon gama/metabolismo , Interleucina-4/metabolismo , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Monócitos/imunologia , Micoses/imunologia , Estudos Prospectivos , Taxa de Sobrevida , Linfócitos T/imunologia , Fatores de Tempo , Receptor 5 Toll-Like/análise , Receptor 7 Toll-Like/análise , Receptor Toll-Like 9/análise , Receptores Toll-Like/agonistas , Transplante Homólogo , Fator de Necrose Tumoral alfa/metabolismo , Adulto Jovem
8.
Environ Sci Pollut Res Int ; 21(10): 6516-24, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24488552

RESUMO

Butyltin (BT) contamination was evaluated in hermit crabs from 25 estuaries and in sediments from 13 of these estuaries along about 2,000 km of the Brazilian coast. BT contamination in hermit crabs ranged from 2.22 to 1,746 ng Sn g(-1) of DBT and 1.32 to 318 ng Sn g(-1) of TBT. In sediment samples, the concentration also varied widely, from 25 to 1,304 ng Sn g(-1) of MBT, from 7 to 158 ng Sn g(-1) of DBT, and from 8 to 565 ng Sn g(-1) of TBT. BTs are still being found in surface sediments and biota of the estuaries after the international and Brazilian bans, showing heterogeneous distribution among and within estuaries. Although hermit crabs were previously tested as an indicator of recent BT contamination, the results indicate the presence of contamination, probably from resuspension of BTs from deeper water of the estuary.


Assuntos
Anomuros/química , Desinfetantes/análise , Monitoramento Ambiental , Estuários , Sedimentos Geológicos/química , Compostos Orgânicos de Estanho/análise , Poluentes Químicos da Água/análise , Animais , Brasil , Pintura/análise
9.
Mar Pollut Bull ; 64(6): 1143-7, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22541642

RESUMO

Microplastics are omnipresent in the oceans and generally have negative impacts on the biota. However, flotsam may increase the availability of hard substrates, which are considered a limiting resource for some oceanic species, e.g. as oviposition sites for the ocean insect Halobates. This study describes the use of plastic pellets as an oviposition site for Halobates micans and discusses possible effects on its abundance and dispersion. Inspection of egg masses on stranded particles on beaches revealed that a mean of 24% (from 0% to 62%) of the pellets bore eggs (mean of 5 and max. of 48 eggs per pellet). Most eggs (63%) contained embryos, while 37% were empty egg shells. This shows that even small plastic particles are used as oviposition site by H. micans, and that marine litter may have a positive effect over the abundance and dispersion of this species.


Assuntos
Heterópteros/fisiologia , Oviposição , Plásticos/análise , Comportamento Sexual Animal/fisiologia , Poluentes Químicos da Água/análise , Animais , Brasil , Monitoramento Ambiental , Feminino , Água do Mar/química , Movimentos da Água , Poluição Química da Água/estatística & dados numéricos
10.
Rev. bras. plantas med ; 12(4): 406-413, out.-dez. 2010. graf, tab
Artigo em Português | LILACS | ID: lil-578980

RESUMO

A Bromelia antiacantha Bertol. (Bromeliaceae), conhecida como gravatá ou caraguatá, apresenta características medicinais, alimentícias e ornamentais. Neste trabalho foram avaliadas as atividades antifúngica, antibacteriana, citotóxica, moluscicida e antioxidante de extratos alcoólicos das folhas e frutos desta espécie. Na avaliação da atividade antimicrobiana pelo método de microdiluição os extratos alcoólicos não foram eficientes frente à cepa referência do fungo Candida albicans (ATCC 90028), cepas clínicas de C. albicans e C. glabrata, e frente às bactérias S. aureus (ATCC 6538), P. aeruginosa (ATCC 9027) e E. coli (ATCC 8739). A atividade citotóxica, avaliada pelo bioensaio de toxicidade sobre náuplios de Artemia salina Leach (TAS), foi positiva para ambos extratos, com valores de DL50 variando em torno de 620 µg mL-1 e 360 µg mL-1, para os extratos alcoólicos dos frutos e das folhas, respectivamente. A atividade moluscicida, avaliada frente a caramujos da espécie Biomphalaria glabrata (Molusca, Gastropoda), não mostrou toxicidade aguda para soluções de 400 µg mL-1. As propriedades antioxidantes dos extratos investigadas in vitro mediante o método de DPPH• foram consideradas modestas (~ 35 por cento de inibição na concentração de 1000 µg mL-1). Dentre as atividades biológicas que foram testadas a atividade citotóxica foi a mais pronunciada.


Bromelia antiacantha Bertol. (Bromeliaceae), popularly known as "gravatá" or "caraguatá", shows medicinal, nutritional and ornamental properties. In the present study, the alcoholic extracts of leaves and fruits of this species were evaluated for antifungal, antibacterial, cytotoxic, molluscicidal and antioxidant activities. The alcoholic extracts evaluated by microdilution method were not efficient against the standard strain of Candida albicans (ATCC 90028), clinical strains of C. albicans and C. glabrata, and S. aureus (ATCC 6538), P. aeruginosa (ATCC 9027) and E. coli (ATCC 8739). The cytotoxic activity evaluated by toxicity bioassay on nauplii of Artemia salina Leach (TAS) was positive for both extracts, with LD50 values ranging around 620 µg mL-1 and 360 µg mL-1 for alcoholic extracts from leaves and fruits, respectively. The molluscicidal activity evaluated against Biomphalaria glabrata (Mollusca, Gastropoda) did not present acute toxicity for 400 µg mL-1 solutions. The antioxidant properties of the extracts investigated in vitro using the DPPH• method were considered modest (~ 35 percent of inhibition at 1000 µg mL-1). Among the evaluated biological activities, cytotoxic activity was the most marked.


Assuntos
Antioxidantes/análise , Bromelia , Citotoxinas/análise , Moluscocidas/análise , Produtos com Ação Antimicrobiana , Extratos Vegetais/biossíntese , Plantas Medicinais
11.
Braz J Biol ; 66(1B): 351-5, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16710527

RESUMO

Sandy beaches in some areas of the São Sebastião Channel in southeastern Brazil have unremittingly undergone a variety of impacts, including the deposition of rock fragments in the intertidal region. Consequently, these environments support a rich fauna comprising both sandy beach and rocky shore organisms. Two rocky shore gastropods, Tegula viridula and Morula nodulosa, are particularly abundant in such environments. An evaluation of the use of microhabitats by these two species revealed that they occupy the available microhabitats in different proportions and the presence of one species is associated with the absence of the other. Morula nodulosa is randomly dispersed, occupying mostly areas with rock fragments covered with sediment and branching brown algae. Tegula viridula shows a clumped dispersion associated with the patchiness of the microhabitats used: the presence of encrusting green algae and absence of sediment and branching brown algae covering the rocks. These findings suggest T. viridula has a lower tolerance than M. nodulosa to sand inundation of the rocky fragments, a stochastic event common to the environment in question.


Assuntos
Gastrópodes/fisiologia , Animais , Brasil , Ecossistema , Densidade Demográfica
12.
Braz. j. biol ; 66(1b): 351-355, Feb. 2006. tab, graf
Artigo em Inglês | LILACS | ID: lil-427223

RESUMO

Praias arenosas em algumas partes do Canal São Sebastião, região sudeste do Brasil, têm sido constantemente submetidas a diferentes tipos de impacto como deposição de fragmentos rochosos na região entremarés. Como conseqüência, estes ambientes abrigam uma rica fauna com organismos tanto de costões rochosos quanto de praias arenosas. Em especial, duas espécies de gastrópode típicas de costões rochosos, Tegula viridula e Morula nodulosa, são muito abundantes nestes ambientes. Uma avaliação do uso de microhabitats por estas duas espécies revelou que elas ocupam os microhabitats disponíveis em diferentes proporções e que a presença de uma espécie esteve associada à ausência da outra. Morula nodulosa apresentou uma dispersão ao acaso ocupando áreas com sedimento e algas marrons ramificadas recobrindo os fragmentos de rocha. Tegula viridula apresentou uma dispersão agrupada associada à característica agrupada dos microambientes ocupados: presença de algas verdes incrustantes e ausência de sedimento e algas marrons ramificadas recobrindo os fragmentos de rocha. Os resultados indicam que T. viridula pode ser menos tolerante que M. nodulosa à inundação dos fragmentos rochosos por sedimento, um evento estocástico comum ao ambiente estudado.


Assuntos
Animais , Ecossistema , Gastrópodes/fisiologia , Brasil , Densidade Demográfica
13.
Braz. j. biol ; 63(3): 469-479, Aug. 2003. ilus, tab, graf
Artigo em Inglês | LILACS | ID: lil-353970

RESUMO

The population biology and the spatial and temporal distribution of Kalliapseudes schubarti Mañé-Garzon, 1949, a common tanaidacean in mud flats and estuaries in southern and southeastern Brazil, was studied in the Araçá region, São Sebastiäo (SP), Brazil. This species showed a clustered dispersion in the area and the individuals were concentrated in the superficial sediment layer (5 cm). Higher densities of K. schubarti were recorded in areas characterized by moderately sorted fine sediment. Multiple regression analysis revealed a positive influence of the organic matter contents and a negative effect of the silt-clay contents on the abundance of K. schubarti. This species showed a marked temporal variation with very low abundance in winter and fall (March to August). Sexual dimorphism was evidenced with males being larger than females. Ovigerous females were also larger than pre-ovigerous ones. Sex ratio was skewed towards females. Seven cohorts were identified during the sampling period, the estimated longevity was 12 months, and no seasonal oscillation in growth was evidenced. The continuous reproduction, as evidenced by the presence of larval phases (manca II and neutron) and reproductive females throughout the year, and high fecundity among the tanaids associated with fast growth and limited longevity support the case for the opportunistic life strategy suggested for this species in the literature.


Assuntos
Animais , Masculino , Feminino , Crustáceos , Análise de Variância , Brasil , Crustáceos , Longevidade , Densidade Demográfica , Dinâmica Populacional , Reprodução , Estações do Ano , Caracteres Sexuais
14.
Braz. j. biol ; 63(3): 537-544, Aug. 2003. ilus
Artigo em Inglês | LILACS | ID: lil-353977

RESUMO

This study describes the daily activity in a simulated high tide situation of four species of hermit crabs (Pagurus criniticornis, Clibanarius antillensis, C. sclopetarius, and C. vittatus) that coexist in an intertidal flat in southeastern Brazil. Observations were done in two-hour intervals during two subsequent days (48 h) in three replicate pools with thirty crabs each. Among species (between and within genera) there was an evident variation in activity patterns, of which three could be distinguished. The circadian activity patterns of C. antillensis and C. vittatus could be characterized as evening and nocturnal, with resting peaks during the morning and afternoon. The circadian activity pattern of C. sclopetarius was characterized by two marked peaks of inactivity, corresponding to dawn and evening, which could represent an intrinsic association with the semi-lunar tidal cycles of the study area. Pagurus criniticornis showed high activity not influenced by day/night conditions during the entire observed period. These activity pattern variations of the studied hermit crabs should be taken into account in designing further experiments. More precise and accurate interspecific behavioral comparisons among species could be achieved in nocturnal experiments, the high activity period of all species.


Assuntos
Animais , Comportamento Animal , Ritmo Circadiano , Brasil
15.
Braz J Biol ; 63(3): 469-79, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-14758706

RESUMO

The population biology and the spatial and temporal distribution of Kalliapseudes schubarti Mañé-Garzon, 1949, a common tanaidacean in mud flats and estuaries in southern and southeastern Brazil, was studied in the Araçá region, São Sebastião (SP), Brazil. This species showed a clustered dispersion in the area and the individuals were concentrated in the superficial sediment layer (5 cm). Higher densities of K. schubarti were recorded in areas characterized by moderately sorted fine sediment. Multiple regression analysis revealed a positive influence of the organic matter contents and a negative effect of the silt-clay contents on the abundance of K. schubarti. This species showed a marked temporal variation with very low abundance in winter and fall (March to August). Sexual dimorphism was evidenced with males being larger than females. Ovigerous females were also larger than pre-ovigerous ones. Sex ratio was skewed towards females. Seven cohorts were identified during the sampling period, the estimated longevity was 12 months, and no seasonal oscillation in growth was evidenced. The continuous reproduction, as evidenced by the presence of larval phases (manca II and neutron) and reproductive females throughout the year, and high fecundity among the tanaids associated with fast growth and limited longevity support the case for the opportunistic life strategy suggested for this species in the literature.


Assuntos
Crustáceos/fisiologia , Análise de Variância , Animais , Brasil , Crustáceos/anatomia & histologia , Feminino , Longevidade , Masculino , Densidade Demográfica , Dinâmica Populacional , Reprodução , Estações do Ano , Caracteres Sexuais
16.
Braz J Biol ; 63(3): 537-44, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-14758713

RESUMO

This study describes the daily activity in a simulated high tide situation of four species of hermit crabs (Pagurus criniticornis, Clibanarius antillensis, C. sclopetarius, and C. vittatus) that coexist in an intertidal flat in southeastern Brazil. Observations were done in two-hour intervals during two subsequent days (48 h) in three replicate pools with thirty crabs each. Among species (between and within genera) there was an evident variation in activity patterns, of which three could be distinguished. The circadian activity patterns of C. antillensis and C. vittatus could be characterized as evening and nocturnal, with resting peaks during the morning and afternoon. The circadian activity pattern of C. sclopetarius was characterized by two marked peaks of inactivity, corresponding to dawn and evening, which could represent an intrinsic association with the semi-lunar tidal cycles of the study area. Pagurus criniticornis showed high activity not influenced by day/night conditions during the entire observed period. These activity pattern variations of the studied hermit crabs should be taken into account in designing further experiments. More precise and accurate interspecific behavioral comparisons among species could be achieved in nocturnal experiments, the high activity period of all species.


Assuntos
Anomuros/fisiologia , Comportamento Animal/fisiologia , Animais , Brasil , Ritmo Circadiano/fisiologia
17.
Braz. j. biol ; 62(4a): 725-733, Nov. 2002. ilus, tab, graf
Artigo em Inglês | LILACS | ID: lil-335629

RESUMO

The hemolysate from Geochelone denticulata contains two main hemoglobin components, as shown by ion exchange chromatography and polyacrylamide gel electrophoresis (PAGE). Electrophoresis under dissociating conditions showed three types of globin chains. The apparent molecular mass, as determined by gel filtration on Sephadex G-200, was compatible with tetrameric Hb, which was unable to polymerize. The G. denticulata Hb has a P50 value of 9.56 mm Hg at pH 7.4. The Hb oxygenation appears to be under the control of organic phosphates and hydrogen ion since it is strongly affected by those species. In the presence ATP or IHP the P50 values increased to 29.51 mm Hg and 54.95 mm Hg, respectively, at pH 7.4. The n50 was generally lower than 1.5 in stripped Hb, suggesting a dissociation of tetramers. In the presence of organic phosphates n50 values increased to approximately 2.5. The Bohr effect was evident in oxygen equilibrium experiments. The hematocrit (32 percent) and Hb concentration (5.7 mM as heme) of G. denticulata blood were substantially larger than those of G. carbonaria, but the methemoglobin levels were similar in both species, approximately 1 percent. Thus, the oxygen capacity of blood appears to be higher in G. denticulata than in G. carbonaria, particularly considering the functional properties of their Hbs, which would guarantee the survival of animals


Assuntos
Animais , Hemoglobinas , Oxigênio , Tartarugas , Cromatografia de Afinidade , Eletroforese em Gel de Poliacrilamida , Hemoglobinas , Concentração de Íons de Hidrogênio , Oxigênio , Oxiemoglobinas
18.
Braz J Biol ; 62(1): 107-12, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12185910

RESUMO

Coexisting hermit crabs may competitively interact for shells and microhabitats, mainly when shell availability is habitat-related. Three species of Clibanarius (C. antillensis, C. sclopetarius, and C. vittatus) coexist in the intertidal region of Pernambuco Islet, Araçá Region, São Sebastião Channel, southeastern Brazil. This study evaluated crab preferences for four substrate types used by these species in nature (rocky shore, pebbles, sand, and mud) in allopatric (single species) and sympatric (three species) treatments in simulations of high tide and low tide. The substrate preference of the three hermit crabs did not vary between low and high tide situations. At low tide the crabs either moved into holes in the highly complex rocky substrate or buried themselves in mud. Substrate selection may explain the patterns of substrate use in nature only for C. vittatus. Clibanarius antillensis and C. sclopetarius showed closer similarities in the pattern of substrate selection in the sympatric treatment with the substrate use in nature than in allopatric treatment, indicating a positive influence (dependence) of the presence of one species on the presence of another. Use of sub-optimal substrates, mainly by C. antillensis, may be caused by other factors such as its low desiccation tolerances. If competition for space takes place among these species, it would be more intense between C. sclopetarius and C. vittatus given their higher overlap in substrate preference than between them and C. antillensis.


Assuntos
Anomuros/fisiologia , Preferências Alimentares/fisiologia , Animais , Brasil , Meio Ambiente , Comportamento Social
19.
Braz. j. biol ; 62(1): 107-112, Feb. 2002. ilus
Artigo em Inglês | LILACS | ID: lil-321292

RESUMO

Coexisting hermit crabs may competitively interact for shells and microhabitats, mainly when shell availability is habitat-related. Three species of Clibanarius (C. antillensis, C. sclopetarius, and C. vittatus) coexist in the intertidal region of Pernambuco Islet, Araçá Region, Säo Sebastiäo Channel, southeastern Brazil. This study evaluated crab preferences for four substrate types used by these species in nature (rocky shore, pebbles, sand, and mud) in allopatric (single species) and sympatric (three species) treatments in simulations of high tide and low tide. The substrate preference of the three hermit crabs did not vary between low and high tide situations. At low tide the crabs either moved into holes in the highly complex rocky substrate or buried themselves in mud. Substrate selection may explain the patterns of substrate use in nature only for C. vittatus. Clibanarius antillensis and C. sclopetarius showed closer similarities in the pattern of substrate selection in the sympatric treatment with the substrate use in nature than in allopatric treatment, indicating a positive influence (dependence) of the presence of one species on the presence of another. Use of sub-optimal substrates, mainly by C. antillensis, may be caused by other factors such as its low desiccation tolerances. If competition for space takes place among these species, it would be more intense between C. sclopetarius and C. vittatus given their higher overlap in substrate preference than between them and C. antillensis


Assuntos
Animais , Braquiúros , Preferências Alimentares , Brasil , Meio Ambiente , Comportamento Social
20.
Braz J Biol ; 62(4A): 725-33, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12659022

RESUMO

The hemolysate from Geochelone denticulata contains two main hemoglobin components, as shown by ion exchange chromatography and polyacrylamide gel electrophoresis (PAGE). Electrophoresis under dissociating conditions showed three types of globin chains. The apparent molecular mass, as determined by gel filtration on Sephadex G-200, was compatible with tetrameric Hb, which was unable to polymerize. The G. denticulata Hb has a P50 value of 9.56 mm Hg at pH 7.4. The Hb oxygenation appears to be under the control of organic phosphates and hydrogen ion since it is strongly affected by those species. In the presence ATP or IHP the P50 values increased to 29.51 mm Hg and 54.95 mm Hg, respectively, at pH 7.4. The n50 was generally lower than 1.5 in stripped Hb, suggesting a dissociation of tetramers. In the presence of organic phosphates n50 values increased to approximately 2.5. The Bohr effect was evident in oxygen equilibrium experiments. The hematocrit (32%) and Hb concentration (5.7 mM as heme) of G. denticulata blood were substantially larger than those of G. carbonaria, but the methemoglobin levels were similar in both species, approximately 1%. Thus, the oxygen capacity of blood appears to be higher in G. denticulata than in G. carbonaria, particularly considering the functional properties of their Hbs, which would guarantee the survival of animals.


Assuntos
Hemoglobinas/fisiologia , Oxigênio/sangue , Tartarugas/sangue , Animais , Cromatografia de Afinidade , Eletroforese em Gel de Poliacrilamida , Hemoglobinas/análise , Concentração de Íons de Hidrogênio , Oxigênio/metabolismo , Oxiemoglobinas/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA