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1.
Proc Natl Acad Sci U S A ; 115(36): 8990-8995, 2018 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-30126981

RESUMO

Coral and macroalgal communities are threatened by global stressors. However, recently reported community shifts from temperate macroalgae to tropical corals offer conservation potential for corals at the expense of macroalgae under climate warming. Although such community shifts are expanding geographically, our understanding of the driving processes is still limited. Here, we reconstruct long-term climate-driven range shifts in 45 species of macroalgae, corals, and herbivorous fishes from over 60 years of records (mainly 1950-2015), stretching across 3,000 km of the Japanese archipelago from tropical to subarctic zones. Based on a revised coastal version of climate velocity trajectories, we found that prediction models combining the effects of climate and ocean currents consistently explained observed community shifts significantly better than those relying on climate alone. Corals and herbivorous fishes performed better at exploiting opportunities offered by this interaction. The contrasting range dynamics for these taxa suggest that ocean warming is promoting macroalgal-to-coral shifts both directly by increased competition from the expansion of tropical corals into the contracting temperate macroalgae, and indirectly via deforestation by the expansion of tropical herbivorous fish. Beyond individual species' effects, our results provide evidence on the important role that the interaction between climate warming and external forces conditioning the dispersal of organisms, such as ocean currents, can have in shaping community-level responses, with concomitant changes to ecosystem structure and functioning. Furthermore, we found that community shifts from macroalgae to corals might accelerate with future climate warming, highlighting the complexity of managing these evolving communities under future climate change.


Assuntos
Antozoários/fisiologia , Peixes/fisiologia , Aquecimento Global , Herbivoria , Oceanos e Mares , Alga Marinha/fisiologia , Animais
2.
Glob Chang Biol ; 23(10): 4440-4452, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28211249

RESUMO

Conservation efforts strive to protect significant swaths of terrestrial, freshwater and marine ecosystems from a range of threats. As climate change becomes an increasing concern, these efforts must take into account how resilient-protected spaces will be in the face of future drivers of change such as warming temperatures. Climate landscape metrics, which signal the spatial magnitude and direction of climate change, support a convenient initial assessment of potential threats to and opportunities within ecosystems to inform conservation and policy efforts where biological data are not available. However, inference of risk from purely physical climatic changes is difficult unless set in a meaningful ecological context. Here, we aim to establish this context using historical climatic variability, as a proxy for local adaptation by resident biota, to identify areas where current local climate conditions will remain extant and future regional climate analogues will emerge. This information is then related to the processes governing species' climate-driven range edge dynamics, differentiating changes in local climate conditions as promoters of species range contractions from those in neighbouring locations facilitating range expansions. We applied this approach to assess the future climatic stability and connectivity of Japanese waters and its network of marine protected areas (MPAs). We find 88% of Japanese waters transitioning to climates outside their historical variability bounds by 2035, resulting in large reductions in the amount of available climatic space potentially promoting widespread range contractions and expansions. Areas of high connectivity, where shifting climates converge, are present along sections of the coast facilitated by the strong latitudinal gradient of the Japanese archipelago and its ocean current system. While these areas overlap significantly with areas currently under significant anthropogenic pressures, they also include much of the MPA network that may provide stepping-stone protection for species that must shift their distribution because of climate change.


Assuntos
Mudança Climática , Ecossistema , Medição de Risco , Ecologia , Água Doce , Japão , Oceanos e Mares
3.
Nat Commun ; 14(1): 1894, 2023 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-37072389

RESUMO

While marine kelp forests have provided valuable ecosystem services for millennia, the global ecological and economic value of those services is largely unresolved. Kelp forests are diminishing in many regions worldwide, and efforts to manage these ecosystems are hindered without accurate estimates of the value of the services that kelp forests provide to human societies. Here, we present a global estimate of the ecological and economic potential of three key ecosystem services - fisheries production, nutrient cycling, and carbon removal provided by six major forest forming kelp genera (Ecklonia, Laminaria, Lessonia, Macrocystis, Nereocystis, and Saccharina). Each of these genera creates a potential value of between $64,400 and $147,100/hectare each year. Collectively, they generate between $465 and $562 billion/year worldwide, with an average of $500 billion. These values are primarily driven by fisheries production (mean $29,900, 904 Kg/Ha/year) and nitrogen removal ($73,800, 657 Kg N/Ha/year), though kelp forests are also estimated to sequester 4.91 megatons of carbon from the atmosphere/year highlighting their potential as blue carbon systems for climate change mitigation. These findings highlight the ecological and economic value of kelp forests to society and will facilitate better informed marine management and conservation decisions.


Assuntos
Ecossistema , Kelp , Humanos , Florestas , Mudança Climática , Carbono
5.
Sci Total Environ ; 790: 148094, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34091336

RESUMO

Increases in sea-surface temperature due to global warming are a major threat to tropical and subtropical corals as exposure to high water temperatures is the primary cause of coral bleaching. To continue receiving high ecosystem services from coral reef ecosystems in the future, it is important to predict the growth conditions of corals and take appropriate countermeasures to protect them at both global and local scales. The Kerama Islands (part of the Nansei Islands, Japan) were selected as the study area. The islands have been designated as a national park and attract substantial tourism, which utilizes the coral reef ecosystem. The selected study site is significant as it is known to act as a source of coral larvae for the surrounding area. In this study, coral bleaching and mortality rates under present and +1.5 °C/+2.0 °C water temperature conditions were estimated using a 1) three-dimensional hydrodynamic model with a spatial resolution of 100 m and 2) statistical model describing the relationship between various environmental parameters and coral bleaching and mortality rates. Applying a local hydrodynamic model enabled us to obtain high-resolution spatial and temporal variations in water temperature and current speed, and these data were used to obtain statistical model data. Coral conservation sites were prioritized based on 1) projections of the spatial distribution of bleaching and mortality rates under global warming conditions and 2) locations of the main diving and conservation points, with the intention of continuing the present use and management locations. The results of this study are expected to contribute to the management of coral reef ecosystems through conservation and adaptation strategies at local scales.


Assuntos
Antozoários , Animais , Recifes de Corais , Ecossistema , Japão , Parques Recreativos , Água do Mar , Temperatura
6.
PeerJ ; 7: e6429, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30809440

RESUMO

BACKGROUND: The coral genus Acropora contains more than 150 species with very high morphological diversity. This high diversity may have been caused by repeated hybridization via mass spawning. However, we have little information whether hybrids are formed in these corals. Identifying morphological differences between hybrids and their parental species would provide an opportunity to find wild hybrids in the field and to understand how colony shapes of Acropora have become highly diversified throughout evolutionary history. In the two morphologically distinctive coral species Acropora florida and A. intermedia in the Indo-Pacific, their gametes show high rates of bi-directional intercrossing in vitro, and thus these two species are ideal species to investigate the morphological traits of the hybrids. METHODS: We examined morphological characters of F1 hybrids from A. florida to A. intermedia, which were produced from in vitro crossing experiments. To compare morphological differences, we grew juveniles and mature colonies of reciprocal F1 hybrids (FLOint: A. florida eggs × A. intermedia sperm, and INTflo: A. intermedia eggs × A. florida sperm) and of the parental species (purebreds of A. intermedia and A. florida). We analyzed skeletal morphology such as colony size, branch length, and branching number, and compared them with those of a putative F1 hybrid between A. florida and A. intermedia found in the field. We also confirmed the molecular phylogenetic position of F1 hybrids, parental species, and a putative F1 hybrid using the mitochondrial non-coding region. RESULTS: Our morphological analysis revealed that branching number of the F1 hybrids was intermediate relative to the parental species. Moreover, the FLOint hybrids were morphologically more closely related to the maternal species A. florida, and the INTflo hybrids were to A. intermedia. Molecular data showed that A. florida and A. intermedia were clearly divided into two clades, and that F1 hybrids grouped in the clade based on their maternal parent. A very similar pattern to the INTflo hybrids was obtained for the putative F1 hybrid in nature. DISCUSSION: Our results revealed that F1 hybrids between two Indo-Pacific species A. florida and A. intermedia had intermediate morphology relative to their parent species but reflected the maternal parent more. Similarity to maternal species in hybrids is opposite to the Caribbean Acropora species that had more paternal morphological characters in hybrids. These results further suggest that some genetic factor in eggs is likely to affect determination of colony shape in the Indo-Pacific. At present, we have considered colonies with intermediate morphs between different species to be intra-specific morphological variation, but they may be real F1 hybrids. Indeed, a putative F1 hybrid represented similar morphological and molecular features to the F1 hybrids, and thus it is plausible to be attributed as a "real" F1 hybrid in nature.

7.
PeerJ ; 6: e4382, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29473007

RESUMO

Coral reefs are one of the world's most threatened ecosystems, with global and local stressors contributing to their decline. Excessive sea-surface temperatures (SSTs) can cause coral bleaching, resulting in coral death and decreases in coral cover. A SST threshold of 1 °C over the climatological maximum is widely used to predict coral bleaching. In this study, we refined thermal indices predicting coral bleaching at high-spatial resolution (1 km) by statistically optimizing thermal thresholds, as well as considering other environmental influences on bleaching such as ultraviolet (UV) radiation, water turbidity, and cooling effects. We used a coral bleaching dataset derived from the web-based monitoring system Sango Map Project, at scales appropriate for the local and regional conservation of Japanese coral reefs. We recorded coral bleaching events in the years 2004-2016 in Japan. We revealed the influence of multiple factors on the ability to predict coral bleaching, including selection of thermal indices, statistical optimization of thermal thresholds, quantification of multiple environmental influences, and use of multiple modeling methods (generalized linear models and random forests). After optimization, differences in predictive ability among thermal indices were negligible. Thermal index, UV radiation, water turbidity, and cooling effects were important predictors of the occurrence of coral bleaching. Predictions based on the best model revealed that coral reefs in Japan have experienced recent and widespread bleaching. A practical method to reduce bleaching frequency by screening UV radiation was also demonstrated in this paper.

8.
Sci Rep ; 8(1): 6674, 2018 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-29691478

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

10.
Sci Rep ; 7(1): 3389, 2017 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-28611440

RESUMO

Determining the success of eradication of an invasive species requires a way to decide when its risk of reoccurrence has become acceptably low. In Japan, the area populated by the Argentine ant, Linepithema humile (Mayr), is expanding, and eradication via chemical treatment is ongoing at various locations. One such program in Tokyo was apparently successful, because the ant population decreased to undetectable levels within a short time. However, construction of a population model for management purposes was difficult because the probability of detecting ants decreases rapidly as the population collapses. To predict the time when the ant was eradicated, we developed a multinomial-mixture model for chemical eradication based on monthly trapping data and the history of pesticide applications. We decided when to declare that eradication had been successful by considering both 'eradication' times, which we associated with eradication probabilities of 95% and 99%, and an optimal stopping time based on a 'minimum expected economic cost' that considered the possibility that surveys were stopped too soon. By applying these criteria, we retroactively declared that Argentine ants had been eradicated 38-42 months after the start of treatments (16-17 months after the last sighting).


Assuntos
Formigas/crescimento & desenvolvimento , Teorema de Bayes , Entomologia/métodos , Controle de Insetos/métodos , Inseticidas/toxicidade , Espécies Introduzidas/estatística & dados numéricos , Modelos Estatísticos , Animais , Formigas/efeitos dos fármacos
11.
Mar Pollut Bull ; 122(1-2): 282-287, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28655461

RESUMO

Ocean acidification is widely recognised to have a negative impact on marine calcifying organisms by reducing calcifications, but controversy remains over whether such organisms could cope with ocean acidification within a range of phenotypic plasticity and/or adapt to future acidifying ocean. We performed a laboratory rearing experiment using clonal fragments of the common branching corals Montipora digitata and Porites cylindrica under control and acidified seawater (lower pH) conditions (approximately 400 and 900µatm pCO2, respectively) and evaluated the intraspecific variations in their responses to ocean acidification. Intra- and interspecific variations in calcification and photosynthetic efficiency were evident according to both pCO2 conditions and colony, indicating that responses to acidification may be individually variable at the colony level. Our results suggest that some corals may cope with ocean acidification within their present genotypic composition by adaptation through phenotypic plasticity, while others may be placed under selective pressures resulting in population alteration.


Assuntos
Adaptação Fisiológica , Antozoários , Recifes de Corais , Animais , Dióxido de Carbono , Concentração de Íons de Hidrogênio , Oceanos e Mares , Fotossíntese , Água do Mar
12.
J Cardiovasc Surg (Torino) ; 47(6): 677-82, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17043615

RESUMO

AIM: The benefits of terminal noncardioplegic warm blood retrograde perfusion (TNWB) and terminal warm blood cardioplegia perfusion (TWBC) after intermittent cold blood cardioplegia perfusion during aortic clamping were studied. METHODS: The clinical results of consecutive 128 patients who underwent on pump coronary artery bypass grafting (CABG) or valvular surgery were studied retrospectively. The aortic cross-clamp was removed (1) after five-minute TWBC and sequential three-minute TNWB in 59 patients (TNWB group), (2) immediately after five-minute TWBC in 29 patients (TWBC group), or (3) with neither TWBC or TNWB in 36 patients (control group). RESULTS: The incidence of spontaneous heart beat recovery was best in TNWB group, second in TNBC, and worst in control group (TNWB: 86, TWBC: 42, CONTROL: 14%). The duration from aortic unclamping to heart beat recovery was shorter in TNWB group than TWBC group (TNWB: 2.1, TWB: 4.3 min). Cardiopulmonary bypass duration after aortic unclamping was shortest in TNWB group, second in TWBC group, and longest in control group (TNWB: 21.3, TWB: 27.5, CONTROL: 46.9 min). The postoperative CPK-MB was lowest in TNWB group (TNWB: 65.3, TWB: 87.7, CONTROL: 91.9U/L). Duration of intubation in TNWB group or TWBC group was shorter than control. CONCLUSIONS: Combination of the terminal noncardioplegic warm blood perfusion and terminal warm blood cardioplegic perfusion contributes to increase the incidence of spontaneous heart beat recovery, shortens cardiopulmonary bypass duration following aortic unclamping, and lowers postoperative CPK-MB.


Assuntos
Aorta/cirurgia , Soluções Cardioplégicas/uso terapêutico , Ponte Cardiopulmonar , Ponte de Artéria Coronária , Circulação Coronária , Parada Cardíaca Induzida/métodos , Doenças das Valvas Cardíacas/cirurgia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Temperatura , Ponte Cardiopulmonar/efeitos adversos , Constrição , Creatina Quinase Forma MB/sangue , Feminino , Parada Cardíaca Induzida/efeitos adversos , Humanos , Hipotermia Induzida , Masculino , Pessoa de Meia-Idade , Traumatismo por Reperfusão Miocárdica/sangue , Traumatismo por Reperfusão Miocárdica/etiologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Perfusão , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
13.
Biochim Biophys Acta ; 1550(1): 70-80, 2001 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-11738089

RESUMO

A novel antimicrobial peptide, anoplin, was purified from the venom of the solitary wasp Anoplius samariensis. The sequence was mostly analyzed by mass spectrometry, which was corroborated by solid-phase synthesis. Anoplin, composed of 10 amino acid residues, Gly-Leu-Leu-Lys-Arg-Ile-Lys-Thr-Leu-Leu-NH2, has a high homology to crabrolin and mastoparan-X, the mast cell degranulating peptides from social wasp venoms, and, therefore, can be predicted to adopt an amphipathic alpha-helix secondary structure. In fact, the circular dichroism (CD) spectra of anoplin in the presence of trifluoroethanol or sodium dodecyl sulfate showed a high content, up to 55%, of the alpha-helical conformation. A modeling study of anoplin based on its homology to mastoparan-X supported the CD results. Biological evaluation using the synthetic peptide revealed that this peptide exhibited potent activity in stimulating degranulation from rat peritoneal mast cells and broad-spectrum antimicrobial activity against both Gram-positive and Gram-negative bacteria. Therefore, this is the first antimicrobial component to be found in the solitary wasp venom and it may play a key role in preventing potential infection by microorganisms during prey consumption by their larvae. Moreover, this peptide is the smallest among the linear alpha-helical antimicrobial peptides hitherto found in nature, which is advantageous for chemical manipulation and medical application.


Assuntos
Antibacterianos/isolamento & purificação , Oligopeptídeos/química , Oligopeptídeos/isolamento & purificação , Venenos de Vespas/química , Venenos de Vespas/isolamento & purificação , Sequência de Aminoácidos , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos , Degranulação Celular , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Feminino , Mastócitos/efeitos dos fármacos , Mastócitos/fisiologia , Testes de Sensibilidade Microbiana , Modelos Moleculares , Oligopeptídeos/farmacologia , Ratos , Alinhamento de Sequência , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Venenos de Vespas/farmacologia , Vespas
14.
Oncogene ; 34(8): 1051-7, 2015 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-24632612

RESUMO

Human epidermal growth factor receptor2/Neu, which is overexpressed in about 30% of human breast cancers, transduces growth signals in large part via the Ras-Raf-MEK-ERK pathway. Nevertheless, it is a matter of controversy whether high ERK activity in breast cancer tissues correlates with better or worse prognosis, leaving the role of ERK activity in the progression of breast cancers unresolved. To address this issue, we live-imaged ERK activity in mammary tumors developed in mouse mammary tumor virus-Neu transgenic mice, which had been crossed with transgenic mice expressing a Förster resonance energy transfer biosensor for ERK. Observation of the tumor by two-photon microscopy revealed significant heterogeneity in ERK activity among the mammary tumor cells. The level of ERK activity in each cell was stable up to several hours, implying a robust mechanism that maintained the ERK activity within a limited range. By sorting the mammary tumor cells on the basis of their ERK activity, we found that ERK(high) cells less efficiently generated tumorspheres in vitro and tumors in vivo than did ERK(low) cells. In agreement with this finding, the expressions of the cancer stem cell markers CD49f, CD24 and CD61 were decreased in ERK(high) cells. These observations suggest that high ERK activity may suppress the self-renewal of mammary cancer stem cells.


Assuntos
MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Transferência Ressonante de Energia de Fluorescência , Neoplasias Mamárias Experimentais/metabolismo , Animais , Antineoplásicos/farmacocinética , Benzamidas/farmacocinética , Sistemas Computacionais , Difenilamina/análogos & derivados , Difenilamina/farmacocinética , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Feminino , Genes erbB-2 , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/patologia , Vírus do Tumor Mamário do Camundongo/genética , Camundongos , Camundongos Transgênicos , Imagem Molecular/métodos , Metástase Neoplásica , Inibidores de Proteínas Quinases/farmacocinética
15.
Ecol Evol ; 5(1): 213-23, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25628878

RESUMO

Seaweed beds play a key role in providing essential habitats and energy to coastal areas, with enhancements in productivity and biodiversity and benefits to human societies. However, the spatial extent of seaweed beds around Japan has decreased due to coastal reclamation, water quality changes, rising water temperatures, and heavy grazing by herbivores. Using monthly mean sea surface temperature (SST) data from 1960 to 2099 and SST-based indices, we quantitatively evaluated the effects of warming seawater on the spatial extent of suitable versus unsuitable habitats for temperate seaweed Ecklonia cava, which is predominantly found in southern Japanese waters. SST data were generated using the most recent multiple climate projection models and emission scenarios (the Representative Concentration Pathways or RCPs) used in the Coupled Model Intercomparison Project phase 5 (CMIP5). In addition, grazing by Siganus fuscescens, an herbivorous fish, was evaluated under the four RCP simulations. Our results suggest that continued warming may drive a poleward shift in the distribution of E. cava, with large differences depending on the climate scenario. For the lowest emission scenario (RCP2.6), most existing E. cava populations would not be impacted by seawater warming directly but would be adversely affected by intensified year-round grazing. For the highest emission scenario (RCP8.5), previously suitable habitats throughout coastal Japan would become untenable for E. cava by the 2090s, due to both high-temperature stress and intensified grazing. Our projections highlight the importance of not only mitigating regional warming due to climate change, but also protecting E. cava from herbivores to conserve suitable habitats on the Japanese coast.

16.
FEBS Lett ; 280(1): 107-11, 1991 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-2009953

RESUMO

Structural studies of retinochrome, and its photoproduct, lumiretinochrome, were done by Fourier transform infrared difference spectroscopy. The absorption bands in the carbonyl stretching region which shift in D2O show the changes in the protein part during the photoreaction. Strong absorption bands in the finger-print region show that the all-trans-retinal chromophore in retinochrome isomerizes to the 11-cis-retinal chromophore in lumiretinochrome upon illumination with yellow-green light at 83K.


Assuntos
Pigmentos da Retina/química , Rodopsina/análogos & derivados , Animais , Decapodiformes , Retina/química , Rodopsina/química , Espectrofotometria Infravermelho
17.
J Mass Spectrom ; 35(2): 242-50, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10679987

RESUMO

Tandem mass spectrometry of a mixture of two peptides that differ from each other by a single mass unit due to mutation is presented. The mutant beta-globin of hemoglobin Hoshida is present along with the normal counterpart, and the amino acid substitution of glutamine for glutamic acid is located within tryptic peptide T5 of M(r) 2057. 9. The mass of the mutated peptide is 1 u lower. In the isotopic cluster for the doubly charged ion of the peptide T5, the resolved ion with mass of 1030.0 represents the normal peptide with 93 (12)C atoms and the mutated one with 92 (12)C and one (13)C atoms. Collision-induced dissociation (CID) of this composite ion identified the mutation by presenting a key fragment derived from the (12)C-only mutant peptide, as reported in a previous study. Similarly, when an ion containing multiple (13)C atoms was selected as a precursor for CID, the mutation could be identified, even in large fragments, by a marked change in the shape of the isotopic cluster for the consecutive product ions. This study demonstrates the merit of selecting a resolved ion rather than the whole isotopic cluster as a precursor in the CID measurements of large peptides or proteins for characterizing heterozygous mutations.


Assuntos
Peptídeos/química , Sequência de Aminoácidos , Espectrometria de Massas , Dados de Sequência Molecular , Peso Molecular , Mutação/genética , Peptídeos/genética , Espectrometria de Massas de Bombardeamento Rápido de Átomos
18.
Neurosci Lett ; 285(1): 29-32, 2000 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-10788700

RESUMO

The structural specificity of alpha-PMTX, a novel peptide toxin derived from wasp venom has been studied on the neuromuscular synapse in the walking leg of the lobster. alpha-PMTX is known to induce repetitive action potentials in the presynaptic axon due to sodium channel inactivation. We synthesized 29 analogs of alpha-PMTX by substituting one or two amino acids and compared threshold concentrations of these mutant toxins for inducing repetitive action potentials. In 13 amino acid residues of alpha-PMTX, Arg-1, Lys-3 and Lys-12 regulate the toxic activity because substitution of these basic amino acid residues with other amino acid residues greatly changed the potency. Determining the structure-activity relationships of PMTXs will help clarifying the molecular mechanism of sodium channel inactivation.


Assuntos
Junção Neuromuscular/fisiologia , Neurotoxinas/metabolismo , Canais de Sódio/metabolismo , Transmissão Sináptica/fisiologia , Venenos de Vespas/metabolismo , Substituição de Aminoácidos/genética , Animais , Proteínas de Insetos , Nephropidae , Junção Neuromuscular/efeitos dos fármacos , Neurotoxinas/genética , Neurotoxinas/toxicidade , Ligação Proteica , Relação Estrutura-Atividade , Transmissão Sináptica/efeitos dos fármacos , Venenos de Vespas/genética , Venenos de Vespas/toxicidade
19.
Neurosci Lett ; 238(3): 99-102, 1997 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-9464629

RESUMO

A new neurotoxin, named alpha-pompilidotoxin (alpha-PMTX) has been found in the venom of the solitary wasp Anoplius safnariensis. In the neuromuscular synapse of the lobster walking leg preparation, alpha-PMTX (10-100 micro/M) caused great enhancement of both the excitatory and inhibitory postsynaptic potentials. Recordings of the excitatory post synaptic currents (EPSCs) at the synaptic sites showed that alpha-PMTX reversibly and dose-dependently potentiates EPSCs. Alpha-PMTX may act primarily on the presynaptic membrane but the mode of action of the toxin is clearly different from other known facilitatory neurotoxins, such as alpha-latrotoxin, apamin or charybdotoxin. This novel toxin will serve as a useful tool in the research field of neuroscience.


Assuntos
Junção Neuromuscular/fisiologia , Transmissão Sináptica/efeitos dos fármacos , Venenos de Vespas/farmacologia , Animais , Relação Dose-Resposta a Droga , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Técnicas In Vitro , Nephropidae , Junção Neuromuscular/efeitos dos fármacos
20.
Toxicon ; 36(3): 485-93, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9637368

RESUMO

The use of mass spectrometry, in which high-energy CID and charge remote fragmentation both of protonated and sodium-attached molecular ions was applied, afforded the structural elucidation of a new acylpolyaminetoxin with Mw=801 Da from the venom of the Brazilian garden spider Nephilengys cruentata. In spite of having the same Mw of the NPTX-2, previously described in the venom of the Joro spider Nephila clavata, neither toxins are isomers. In order to differentiate them by using the most usual nomenclature, the new toxin was named NPTX-801C and the NPTX-2 was renamed to NPTX-801E. Both toxins have as common structure the 4-hydroxyindole-3-acetyl-asparaginyl-cadaveryl moiety in their molecules and their structure may be represented in a simplified way: NPTX-801E is HO-indole-Asn-Cad-Pta-Orn-Arg and NPTX-801C is HO-indole-Asn-Cad-Gly-Put-Pta-Pta.


Assuntos
Poliaminas/isolamento & purificação , Venenos de Aranha/química , Aminoácidos/análise , Animais , Brasil , Cromatografia Líquida de Alta Pressão , Peso Molecular , Poliaminas/química , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Ultravioleta , Venenos de Aranha/isolamento & purificação
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