Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.727
Filtrar
1.
Mar Biotechnol (NY) ; 23(5): 724-735, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34528162

RESUMO

Sea stars can adhere to various underwater substrata using an adhesive secretion of which Sfp1 is a major component. Sfp1 is a multimodular protein composed of four subunits (Sfp1 Alpha, Beta, Delta, and Gamma) displaying different functional domains. We recombinantly produced two fragments of Sfp1 comprising most of its functional domains: the C-terminal part of the Beta subunit (rSfp1 Beta C-term) and the Delta subunit (rSfp1 Delta). Surface plasmon resonance analyses of protein adsorption onto different model surfaces showed that rSfp1 Beta C-term exhibits a significantly higher adsorption than the fibrinogen control on hydrophobic, hydrophilic protein-resistant, and charged self-assembled monolayers, while rSfp1 Delta adsorbed more on negatively charged and on protein-resistant surfaces compared to fibrinogen. Truncated recombinant rSfp1 Beta C-term proteins were produced in order to investigate the role of the different functional domains in the adsorption of this protein. The analysis of their adsorption capacities on glass showed that two mechanisms are involved in rSfp1 Beta C-term adsorption: (1) one mediated by the EGF-like domain and involving Ca2+ and Mg2+ ions, and (2) one mediated by the sequence of Sfp1 Beta with no homology with known functional domain in databases, in the presence of Na+, Ca2+ and Mg2+ ions.


Assuntos
Adesivos/química , Proteínas/química , Estrelas-do-Mar/química , Adsorção , Animais , Subunidades Proteicas/química , Proteínas Recombinantes , Ressonância de Plasmônio de Superfície
2.
Elife ; 102021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34488941

RESUMO

Sulfakinin (SK)/cholecystokinin (CCK)-type neuropeptides regulate feeding and digestion in protostomes (e.g. insects) and chordates. Here, we characterised SK/CCK-type signalling for the first time in a non-chordate deuterostome - the starfish Asterias rubens (phylum Echinodermata). In this species, two neuropeptides (ArSK/CCK1, ArSK/CCK2) derived from the precursor protein ArSK/CCKP act as ligands for an SK/CCK-type receptor (ArSK/CCKR) and these peptides/proteins are expressed in the nervous system, digestive system, tube feet, and body wall. Furthermore, ArSK/CCK1 and ArSK/CCK2 cause dose-dependent contraction of cardiac stomach, tube foot, and apical muscle preparations in vitro, and injection of these neuropeptides in vivo triggers cardiac stomach retraction and inhibition of the onset of feeding in A. rubens. Thus, an evolutionarily ancient role of SK/CCK-type neuropeptides as inhibitory regulators of feeding-related processes in the Bilateria has been conserved in the unusual and unique context of the extra-oral feeding behaviour and pentaradial body plan of an echinoderm.


Assuntos
Colecistocinina/metabolismo , Colecistocinina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Animais , Asterias/genética , Asterias/metabolismo , Proteínas Quinases Dependentes de Cálcio-Calmodulina , Linhagem Celular , Equinodermos , Sistema Nervoso/metabolismo , Neuropeptídeos/classificação , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Filogenia , Estrelas-do-Mar
3.
Molecules ; 26(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34443682

RESUMO

Atherosclerosis is the main cause of cardiovascular diseases which in turn, lead to the highest number of mortalities globally. This pathophysiological condition is developed due to a constant elevated level of plasma cholesterols. Statin is currently the widely used treatment in reducing the level of cholesterols, however, it may cause adverse side effects. Therefore, there is an urgent need to search for new alternative treatment. PCSK9 is an enzyme responsible in directing LDL-receptor (LDL-R)/LDL-cholesterols (LDL-C) complex to lysosomal degradation, preventing the receptor from recycling back to the surface of liver cells. Therefore, PCSK9 offers a potential target to search for small molecule inhibitors which inhibit the function of this enzyme. In this study, a marine invertebrate Acanthaster planci, was used to investigate its potential in inhibiting PCSK9 and lowering the levels of cholesterols. Cytotoxicity activity of A. planci on human liver HepG2 cells was carried out using the MTS assay. It was found that methanolic extract and fractions did not exhibit cytotoxicity effect on HepG2 cell line with IC50 values of more than 30 µg/mL. A compound deoxythymidine also did not exert any cytotoxicity activity with IC50 value of more than 4 µg/mL. Transient transfection and luciferase assay were conducted to determine the effects of A. planci on the transcriptional activity of PCSK9 promoter. Methanolic extract and Fraction 2 (EF2) produced the lowest reduction in PCSK9 promoter activity to 70 and 20% of control at 12.5 and 6.25 µg/mL, respectively. In addition, deoxythymidine also decreased PCSK9 promoter activity to the lowest level of 60% control at 3.13 µM. An in vivo study using Sprague Dawley rats demonstrated that 50 and 100 mg/kg of A. planci methanolic extract reduced the total cholesterols and LDL-C levels to almost similar levels of untreated controls. The level of serum glutamate oxalate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) showed that the administration of the extract did not produce any toxicity effect and cause any damage to rat liver. The results strongly indicate that A. planci produced a significant inhibitory activity on PCSK9 gene expression in HepG2 cells which may be responsible for inducing the uptake of cholesterols by liver, thus, reducing the circulating levels of total cholesterols and LDL-C. Interestingly, A. planci also did show any adverse hepato-cytotoxicity and toxic effects on liver. Thus, this study strongly suggests that A. planci has a vast potential to be further developed as a new class of therapeutic agent in lowering the blood cholesterols and reducing the progression of atherosclerosis.


Assuntos
Colesterol/sangue , Pró-Proteína Convertase 9/antagonistas & inibidores , Estrelas-do-Mar/química , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Morte Celular , Proliferação de Células , LDL-Colesterol/sangue , Células Hep G2 , Humanos , Luciferases/metabolismo , Masculino , Metanol , Regiões Promotoras Genéticas/genética , Pró-Proteína Convertase 9/genética , Pró-Proteína Convertase 9/metabolismo , Ratos Sprague-Dawley , Timidina/farmacologia , Triglicerídeos/sangue
4.
DNA Res ; 28(4)2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34387305

RESUMO

The crown-of-thorns starfish (COTS) is a coral predator that is widely distributed in Indo-Pacific Oceans. A previous phylogenetic study using partial mitochondrial sequences suggested that COTS had diverged into four distinct species, but a nuclear genome-based analysis to confirm this was not conducted. To address this, COTS species nuclear genome sequences were analysed here, sequencing Northern Indian Ocean (NIO) and Red Sea (RS) species genomes for the first time, followed by a comparative analysis with the Pacific Ocean (PO) species. Phylogenetic analysis and ADMIXTURE analysis revealed clear divergences between the three COTS species. Furthermore, within the PO species, the phylogenetic position of the Hawaiian sample was further away from the other Pacific-derived samples than expected based on the mitochondrial data, suggesting that it may be a PO subspecies. The pairwise sequentially Markovian coalescent model showed that the trajectories of the population size diverged by region during the Mid-Pleistocene transition when the sea-level was dramatically decreased, strongly suggesting that the three COTS species experienced allopatric speciation. Analysis of the orthologues indicated that there were remarkable genes with species-specific positive selection in the genomes of the PO and RS species, which suggested that there may be local adaptations in the COTS species.


Assuntos
Evolução Biológica , Genoma , Filogenia , Estrelas-do-Mar/genética , Animais , Genômica , Filogeografia , Análise de Sequência de DNA
5.
Elife ; 102021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34342579

RESUMO

Meiosis is a specialized cell cycle that requires sequential changes to the cell division machinery to facilitate changing functions. To define the mechanisms that enable the oocyte-to-embryo transition, we performed time-course proteomics in synchronized sea star oocytes from prophase I through the first embryonic cleavage. Although we found that protein levels were broadly stable, our analysis reveals that dynamic waves of phosphorylation underlie each meiotic stage. We found that the phosphatase PP2A-B55 is reactivated at the meiosis I/meiosis II (MI/MII) transition, resulting in the preferential dephosphorylation of threonine residues. Selective dephosphorylation is critical for directing the MI/MII transition as altering PP2A-B55 substrate preferences disrupts key cell cycle events after MI. In addition, threonine to serine substitution of a conserved phosphorylation site in the substrate INCENP prevents its relocalization at anaphase I. Thus, through its inherent phospho-threonine preference, PP2A-B55 imposes specific phosphoregulated behaviors that distinguish the two meiotic divisions.


Assuntos
Meiose , Oócitos/fisiologia , Monoéster Fosfórico Hidrolases/metabolismo , Estrelas-do-Mar/genética , Animais , Fosforilação , Estrelas-do-Mar/enzimologia
6.
Biol Bull ; 241(1): 77-91, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34436965

RESUMO

AbstractIn recent years, low-salinity events characterized by high temperatures (18-23 °C) and low-salinity waters (20‰-22‰) have increased during late spring and summer, when many marine invertebrate larvae are developing. The present study examines the effects of low-salinity events on particle ingestion for larvae of two echinoderm species, the sea star Pisaster ochraceus and the sand dollar Dendraster excentricus. Larvae were exposed to high temperatures and low salinities for 24 hours, followed by feeding on the alga Isochrysis galbana in high or low salinity for another 10 minutes. Exposing Pisaster larvae to high temperatures and low salinities, followed by feeding in low salinity, did not impair ingestion rates. In fact, these larvae ingested particles at similar and sometimes higher rates than those in the controls. In sharp contrast, a 24-hour exposure to a high temperature and low salinity, followed by continued exposure to low salinity to feed, led to a decrease in the number of particles ingested by 8-arm Dendraster larvae. Larvae of both species captured very few particles when returned to 30‰ after a low-salinity event, indicating that continuous interruption of larval feeding by low-salinity events during development could be deleterious. Sand dollar larvae may have responded negatively to low-salinity events in our experiments because they are found in protected bays, where they may seldom experience these events.


Assuntos
Salinidade , Ouriços-do-Mar , Animais , Larva , Estrelas-do-Mar , Temperatura
7.
Sci Rep ; 11(1): 16819, 2021 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-34413402

RESUMO

We here analysed the populations' genetic structure of Coscinasterias tenuispina, an Atlantic-Mediterranean fissiparous starfish, focusing on the western Mediterranean, to investigate: the distribution and prevalence of genetic variants, the relative importance of asexual reproduction, connectivity across the Atlantic-Mediterranean transition, and the potential recent colonisation of the Mediterranean Sea. Individuals from 11 Atlantic-Mediterranean populations of a previous study added to 172 new samples from five new W Mediterranean sites. Individuals were genotyped at 12 microsatellite loci and their gonads histologically analysed for sex determination. Additionally, four populations were genotyped at two-time points. Results demonstrated genetic homogeneity and low clonal richness within the W Mediterranean, due to the dominance of a superclone, but large genetic divergence with adjacent areas. The lack of new genotypes recruitment over time, and the absence of females, confirmed that W Mediterranean populations were exclusively maintained by fission and reinforced the idea of its recent colonization. The existence of different environmental conditions among basins and/or density-depend processes could explain this lack of recruitment from distant areas. The positive correlation between clonal richness and heterozygote excess suggests that most genetic diversity is retained within individuals in the form of heterozygosity in clonal populations, which might increase their resilience.


Assuntos
Estrelas-do-Mar/genética , Animais , Teorema de Bayes , Células Clonais , Análise por Conglomerados , Feminino , Variação Genética , Geografia , Gônadas/fisiologia , Heterozigoto , Larva/genética , Masculino , Região do Mediterrâneo , Processos de Determinação Sexual , Fatores de Tempo
8.
Proc Biol Sci ; 288(1957): 20211195, 2021 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-34428964

RESUMO

The prevalence of disease-driven mass mortality events is increasing, but our understanding of spatial variation in their magnitude, timing and triggers are often poorly resolved. Here, we use a novel range-wide dataset comprised 48 810 surveys to quantify how sea star wasting disease affected Pycnopodia helianthoides, the sunflower sea star, across its range from Baja California, Mexico to the Aleutian Islands, USA. We found that the outbreak occurred more rapidly, killed a greater percentage of the population and left fewer survivors in the southern half of the species's range. Pycnopodia now appears to be functionally extinct (greater than 99.2% declines) from Baja California, Mexico to Cape Flattery, Washington, USA and exhibited severe declines (greater than 87.8%) from the Salish Sea to the Gulf of Alaska. The importance of temperature in predicting Pycnopodia distribution rose more than fourfold after the outbreak, suggesting latitudinal variation in outbreak severity may stem from an interaction between disease severity and warmer waters. We found no evidence of population recovery in the years since the outbreak. Natural recovery in the southern half of the range is unlikely over the short term. Thus, assisted recovery will probably be required to restore the functional role of this predator on ecologically relevant time scales.


Assuntos
Estrelas-do-Mar , Síndrome de Emaciação , Alaska , Animais , México/epidemiologia , Temperatura
9.
PLoS One ; 16(8): e0255304, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34379665

RESUMO

Coral reefs are increasingly affected by a combination of acute and chronic disturbances from climate change and local stressors. The coral reefs of the Republic of Kiribati's Gilbert Islands are exposed to frequent heat stress caused by central-Pacific type El Niño events, and may provide a glimpse into the future of coral reefs in other parts of the world, where the frequency of heat stress events will likely increase due to climate change. Reefs in the Gilbert Islands experienced a series of acute disturbances over the past fifteen years, including mass coral bleaching in 2004-2005 and 2009-2010, and an outbreak of the corallivorous sea star Acanthaster cf solaris, or Crown-of-Thorns (CoTs), in 2014. The local chronic pressures including nutrient loading, sedimentation and fishing vary within the island chain, with highest pressures on the reefs in urbanized South Tarawa Atoll. In this study, we examine how recovery from acute disturbances differs across a gradient of human influence in neighboring Tarawa and Abaiang Atolls from 2012 through 2018. Benthic cover and size frequency data suggests that local coral communities have adjusted to the heat stress via shifts in the community composition to more temperature-tolerant taxa and individuals. In densely populated South Tarawa, we document a phase shift to the weedy and less bleaching-sensitive coral Porites rus, which accounted for 81% of all coral cover by 2018. By contrast, in less populated Abaiang, coral communities remained comparatively more diverse (with higher percentages of Pocillopora and the octocoral Heliopora) after the disturbances, but reefs had lower overall hard coral cover (18%) and were dominated by turf algae (41%). The CoTs outbreak caused a decline in the cover and mean size of massive Porites, the only taxa that was a 'winner' of the coral bleaching events in Abaiang. Although there are signs of recovery, the long-term trajectory of the benthic communities in Abaiang is not yet clear. We suggest three scenarios: they may remain in their current state (dominated by turf algae), undergo a phase shift to dominance by the macroalgae Halimeda, or recover to dominance by thermally tolerant hard coral genera. These findings provide a rare glimpse at the future of coral reefs around the world and the ways they may be affected by climate change, which may allow scientists to better predict how other reefs will respond to increasing heat stress events across gradients of local human disturbance.


Assuntos
Recifes de Corais , Animais , El Niño Oscilação Sul , Estrelas-do-Mar
10.
Mar Pollut Bull ; 170: 112659, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34217050

RESUMO

Coral reefs are declining at an unprecedented rate as a consequence of local and global stressors. Using a 26-year monitoring database, we analyzed the loss and recovery dynamics of coral communities across seven islands and three archipelagos in French Polynesia. Reefs in the Society Islands recovered relatively quickly after disturbances, which was driven by the recovery of corals in the genus Pocillopora (84% of the total recovery). In contrast, reefs in the Tuamotu and Austral archipelagos recovered poorly or not at all. Across archipelagos, predation by crown-of-thorns starfish and destruction by cyclones outweighed the effects of heat stress events on coral mortality. Despite the apparently limited effect of temperature-mediated stressors, the homogenization of coral communities towards dominance of Pocillopora in the Society Archipelago and the failure to fully recover from disturbances in the other two archipelagos concern the resilience of Polynesian coral communities in the face of intensifying climate-driven stressors.


Assuntos
Antozoários , Tempestades Ciclônicas , Animais , Recifes de Corais , Estrelas-do-Mar , Temperatura
11.
Hand Clin ; 37(3): 447-455, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34253317

RESUMO

For those patients with partial hand level amputation who would benefit from myoelectric prosthetic digits for enhanced prehensile function, the Starfish Procedure provides muscle transfers, which allow for the generation of intuitively controlled electromyographic signals for individual digital control with minimal myoelectric cross-talk. Thoughtful preoperative planning allows for creation of multiple sources of high-quality myoelectric signal in a single operation, which does not require microsurgery, providing for wide applicability to hand surgeons of all backgrounds.


Assuntos
Membros Artificiais , Transferência de Nervo , Amputação , Animais , Eletromiografia , Mãos , Humanos , Músculo Esquelético , Desenho de Prótese , Estrelas-do-Mar
12.
Biol Bull ; 240(3): 200-204, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34129441

RESUMO

AbstractWe explored a modified, computer-aided monitoring system for continuous, long-term recording of Bivalvia cardiac activity. To estimate the capabilities of this system, we used it to monitor the cardiac activity of a mussel (Mytilus edulis) under predation threat from a starfish (Asterias rubens). In addition, we used a web camera to track the behavioral responses of these animals. Compared to its state during normal feeding activity, the mussel's heart rate showed no significant changes when the mussel was near the starfish. However, when the mussel was attacked by the starfish, its heart rate and contraction power (i.e., amplitude) increased and subsequently decreased down to the absence of any heartbeats within 2.5 hours. The results obtained in this study proved the usefulness of this new system as a stress-monitoring tool.


Assuntos
Asterias , Mytilus edulis , Animais , Computadores , Comportamento Predatório , Estrelas-do-Mar
13.
Zootaxa ; 4980(3): 401450, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34186970

RESUMO

Recent expeditions to Rapa Nui (also known as Easter Island) and New Caledonia have revealed undescribed species from mesophotic and deeper depths. This includes three new species from Rapa Nui, Hacelia raaraa, Linckia profunda (Ophidiasteridae), Uokeaster ahi (Asterodiscididae) and two new species from New Caledonia, Astroglypha pyramidata n. gen. and Ophidiaster colossus (Ophidiasteridae). The new genus Astroglypha is described for A. pyramidata but the genus also includes the Atlantic Tamaria passiflora, which is reassigned herein. Pauliastra n. gen. is designated as a replacement for the homonym issue with Pauliella. New occurrences and synonymies are addressed for taxa related to New Caledonia, Rapa Nui and adjacent regions. A morphology based phylogenetic analysis agrees with prior work which placed Goniaster among the Asterodiscididae and posits biogeographic relationships among asterodiscidid genera. Implications for the Goniasteridae and placement of Goniaster among asterodiscidid genera are discussed. Biogeography and relationships among taxa from Rapa Nui and New Caledonia are reviewed. In situ observations from species observed from Rapa Nui are included.


Assuntos
Estrelas-do-Mar , Distribuição Animal , Animais , Nova Caledônia , Filogenia , Polinésia , Estrelas-do-Mar/classificação
14.
Int J Biol Macromol ; 185: 31-39, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34144063

RESUMO

This study was aimed to determine the efficacy of combination of fucoidan from the brown algae Fucus evanescens (FeF) or its derivatives with thornasteroside A (ThA) or asteropsiside A (AsA) from the starfish Asteropsis carinifera in combating human melanoma cells. In vitro MTS and soft agar methods were performed to determine effect of FeF, its derivatives, ThA, AsA or their combination on proliferation and colony formation of SK-MEL-28 cells in 2D and 3D culture. Desulfation of FeF, but not deacetylation, led decreasing of its Mw and anti-proliferative activity. The combinatorial effect of FeF with ThA and AsA depended on the sequences of treatment by compounds. There was additive anticancer effect of FeF with ThA or AsA during simultaneous treatment of cells. ThA and AsA were not active against SK-MEL-28 cells after their pre-treatment with FeF. Potential synergism of action was identified only when SK-MEL-28 cells were pre-treated with ThA and AsA and then by FeF. This process going through the regulation of MEK1/2/ERK1/2/MSK1 pathway and expression of the cell cycle proteins as determined by Western Blot. Thus, the combination of fucoidan with the asterosaponins opens up the prospects for the development of effective combined chemotherapeutic methods for melanoma treatment.


Assuntos
Antineoplásicos/farmacologia , Fucus/química , Melanoma/metabolismo , Polissacarídeos/farmacologia , Saponinas/farmacologia , Estrelas-do-Mar/química , Animais , Antineoplásicos/química , Carbazóis/química , Carbazóis/farmacologia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Melanoma/tratamento farmacológico , Modelos Biológicos , Polissacarídeos/química , Saponinas/química
15.
Dis Aquat Organ ; 145: 21-33, 2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34080580

RESUMO

Sea star wasting disease (SSWD) refers to a suite of poorly described non-specific clinical signs including abnormal posture, epidermal ulceration, and limb autotomy (sloughing) causing mortalities of over 20 species of sea stars and subsequent ecological shifts throughout the northeastern Pacific. While SSWD is widely assumed to be infectious, with environmental conditions facilitating disease progression, few data exist on cellular changes associated with the disease. This is unfortunate, because such observations could inform mechanisms of disease pathogenesis and host susceptibility. Here, we replicated SSWD by exposing captive Pisaster ochraceus to a suite of non-infectious organic substances and show that development of gross lesions is a basal-to-surface process involving inflammation (e.g. infiltration of coelomocytes) of ossicles and mutable collagenous tissue, leading to epidermal ulceration. Affected sea stars also manifest increases in a heretofore undocumented coelomocyte type, spindle cells, that might be a useful marker of inflammation in this species. Finally, compared to purple morphs, orange P. ochraceus developed more severe lesions but survived longer. Longer-lived, and presumably more visible, severely-lesioned orange sea stars could have important demographic implications in terms of detectability of lesioned animals in the wild and measures of apparent prevalence of disease.


Assuntos
Estrelas-do-Mar , Síndrome de Emaciação , Animais , Fenótipo , Síndrome de Emaciação/veterinária
16.
Mar Environ Res ; 169: 105363, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34030089

RESUMO

Disease shapes community composition by removing species with strong interactions. To test whether the absence of keystone predation due to disease produced changes to the species composition of rocky intertidal communities, we leverage a natural experiment involving mass mortality of the keystone predator Pisaster ochraceus from Sea Star Wasting Syndrome. Over four years, we measured dimensions of mussel beds, sizes of Mytilus californianus, mussel recruitment, and species composition on vertical rock walls at six rocky intertidal sites on the central California coast. We also assessed the relationship between changes in mussel cover and changes in sea star density across 33 sites along the North American Pacific coast using data from long-term monitoring. After four years, the lower boundary of the central California mussel beds shifted downward toward the water 18.7 ± 15.8 cm (SD) on the rock and 11.7 ± 11.0 cm in elevation, while the upper boundary remained unchanged. In central California, downward expansion and total area of the mussel bed were positively correlated with mussel recruitment but were not correlated with pre-disease sea star density or biomass. At a multi-region scale, changes in mussel percent cover were positively correlated with pre-disease sea star densities but not change in densities. Species composition of primary substrate holders and epibionts below the mussel bed remained similar across years. Extirpation of the community below the bed did not occur. Instead, this community became limited to a smaller spatial extent while the mussel bed expanded.


Assuntos
Mytilus , Comportamento Predatório , Animais , Biomassa , Estrelas-do-Mar
17.
Mar Pollut Bull ; 168: 112445, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33991988

RESUMO

Logging and plantation agriculture are vital to economies and livelihoods in tropical nations, including Papua New Guinea. To meet global demand, hundreds of thousands of ha of diverse natural habitat have been logged, cleared and replaced with monoculture crops. Resulting hydrological changes have increased sediment, nutrient and pesticide runoff, impacting down-stream habitats. Here, case studies from Kimbe Bay (New Britain) and Mullins Harbour (Milne Bay), examine effects on nearshore coral reefs. In both places, logging and oil palm development had destabilized soils and removed or degraded riparian vegetation. Downstream, nearshore reefs had high silt levels, which, coincident with minor coral bleaching and predation by crown-of-thorns starfish, were correlated with high levels of coral mortality and low coral species richness. Sediment and related impacts can be reduced by effective catchment management, such as avoiding steep slopes, expanding stream and coastal buffer zones, minimizing fertilizer and pesticide use, monitoring and reactive management.


Assuntos
Antozoários , Recifes de Corais , Animais , Ecossistema , Papua Nova Guiné , Estrelas-do-Mar
18.
Environ Pollut ; 285: 117401, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34051567

RESUMO

Methylmercury accumulated at the top of aquatic food chains constitutes a toxicological risk to humans and other top predators. Biomagnification of methylmercury takes place among vertebrates at the higher trophic levels, but this process is less elucidated in benthic invertebrates at the lower trophic levels. Therefore, we investigated the accumulation from food and elimination of methylmercury and inorganic mercury in the benthic sea star Asterias rubens (L.) - a representative of trophic level ~3 - in laboratory experiments. Sea stars fed over 49 days with contaminated mussels (Mytilus edulis) accumulate methylmercury and inorganic mercury to the highest concentrations in the digestive glands, the pyloric caeca, less in stomach, gonad, tube feet, aboral body wall and not to detectable levels in the coelomic fluid. Concerning whole body contents, steady states were reached for both methylmercury and inorganic mercury during the 7-week feeding period and the sea stars reached approximately ½ and » of the concentrations in the mussel food for the two mercury forms, respectively. Half-lives for the elimination of the two mercury forms varied between 45 and 173 days in a 140-d elimination period following the feeding period; inorganic mercury was eliminated faster than methylmercury. Examination of total mercury concentrations in field-collected sea stars confirmed this lack of trophic magnification in relation to the major food items, soft parts of molluscs. We suggest that mercury is not trophically magnified in sea stars 1) because they eliminate methylmercury faster than larger fish and decapod crustaceans and 2) maybe more importantly, because inorganic mercury with its faster elimination constitutes a larger fraction of the total mercury in the food at the lower trophic levels - as opposed to methylmercury which dominates at the higher trophic levels.


Assuntos
Asterias , Mercúrio , Compostos de Metilmercúrio , Mytilus edulis , Poluentes Químicos da Água , Animais , Cadeia Alimentar , Humanos , Mercúrio/análise , Estrelas-do-Mar , Poluentes Químicos da Água/análise
19.
Development ; 148(10)2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-34042967

RESUMO

Regeneration as an adult developmental process is in many aspects similar to embryonic development. Although many studies point out similarities and differences, no large-scale, direct and functional comparative analyses between development and regeneration of a specific cell type or structure in one animal exist. Here, we use the brittle star Amphiura filiformis to characterise the role of the FGF signalling pathway during skeletal development in embryos and arm regeneration. In both processes, we find ligands expressed in ectodermal cells that flank underlying skeletal mesenchymal cells, which express the receptors. Perturbation of FGF signalling showed inhibited skeleton formation in both embryogenesis and regeneration, without affecting other key developmental processes. Differential transcriptome analysis finds mostly differentiation genes rather than transcription factors to be downregulated in both contexts. Moreover, comparative gene analysis allowed us to discover brittle star-specific differentiation genes. In conclusion, our results show that the FGF pathway is crucial for skeletogenesis in the brittle star, as in other deuterostomes, and provide evidence for the re-deployment of a developmental gene regulatory module during regeneration.


Assuntos
Desenvolvimento Ósseo/fisiologia , Regeneração Óssea/fisiologia , Osso e Ossos/embriologia , Fatores de Crescimento de Fibroblastos/metabolismo , Estrelas-do-Mar/embriologia , Animais , Osso e Ossos/metabolismo , Ectoderma/citologia , Ectoderma/metabolismo , Desenvolvimento Embrionário/genética , Extremidades/crescimento & desenvolvimento , Mesoderma/citologia , Mesoderma/metabolismo , Pirróis/farmacologia , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Transdução de Sinais/fisiologia , Estrelas-do-Mar/genética , Estrelas-do-Mar/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
20.
Asian Pac J Cancer Prev ; 22(5): 1365-1373, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34048163

RESUMO

Cancer is an uncontrolled multiplication of cells. The desire efficacy and severe toxicity of current anticancer drugs urge exploring and investigating a better alternative to existing chemotherapeutics. Natural products of marine origin are excellent sources of potential new drugs of enhanced biological activities. OBJECTIVES: Thus, the cytotoxic effects along with investigating the mode of cell death exerted by fractions, AP-9, AP-THR, DS-8 and DS-9 fraction of Acanthaster planci, Diadema setosum sp., on the human cervical cancer cell line, HeLa. METHODS: The cytotoxicity of fractions has determined by using an MTS assay. The early and late apoptosis was studied by using the High content Screening (HCS) instrument. RESULTS: The four fractions produced effective cytotoxicity effects with IC50 values at 72hr of less than 20 µg/ml in the order of AP-9 > DS-9 > APTHR-9 > DS-8. The fraction s exhibited cytotoxicity via mediating apoptotic mode of cell death. The early apoptosis by exposure of phosphatidylserine to the outer leaflet of the plasma membrane and late apoptosis due to the presence of green stain (DNA fragmentation) in treated cells. CONCLUSION: The potent bioactive compounds might be responsible for inducing apoptosis in cancer cells and, thus, the potential to be a successful candidate for exploring upcoming chemotherapeutic drugs.


Assuntos
Antineoplásicos/farmacologia , Apoptose , Ouriços-do-Mar/química , Estrelas-do-Mar/química , Extratos de Tecidos/farmacologia , Neoplasias do Colo do Útero/tratamento farmacológico , Animais , Proliferação de Células , Feminino , Células HeLa , Humanos , Neoplasias do Colo do Útero/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...