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1.
PLoS One ; 15(5): e0233513, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32437403

RESUMO

Due to climate change, numerous ice bodies have been lost in the West Antarctic Peninsula (WAP). As a consequence, deglaciation is expected to impact the marine environment and its biota at physiological and ecosystem levels. Nuculana inaequisculpta is a marine bivalve widely distributed around Antarctica that plays an important role for ecosystem functioning. Considering that N. inaequisculpta inhabits coastal areas under effect of glacial melt and retreat, impacts on its nutritional condition are expected due to alterations on its physiology and food availability. To test this hypothesis, biochemical composition (lipids, proteins, and fatty acids) and energy content were measured in individuals of N. inaequisculpta collected in a fjord at different distances to the retreating glacier in the WAP. Oceanographic parameters of the top and bottom-water layers (temperature, salinity, dissolved oxygen, and chlorophyll-a) were measured to investigate how the environment changes along the fjord. Results showed that surface oceanographic parameters displayed a lower temperature and dissolved oxygen, but a higher salinity and chlorophyll-a content at nearest compared to farthest sites to the glacier. In contrast, a lower temperature and chlorophyll-a, and a higher salinity and dissolved oxygen was measured in the bottom-water layer toward the glacier. N. inaequisculpta had a higher amount of lipids (17.42 ± 3.24 vs. 12.16 ± 3.46%), protein (24.34 ± 6.12 vs. 21.05 ± 2.46%) and energy content (50.57 ± 6.97 J vs. 39.14 ± 5.80 J) in the farthest compared to the nearest site to the glacier. No differences were found in total fatty acids among all sites. It seems likely that lower individual fitness related to proximity to the glacier would not be related to nutritional quality of sediment food, but rather to food quantity.


Assuntos
Bivalves/fisiologia , Mudança Climática , Camada de Gelo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Regiões Antárticas , Bivalves/química , Ecossistema , Estuários , Ácidos Graxos/análise , Camada de Gelo/química , Lipídeos/análise , Proteínas/análise
2.
PLoS One ; 15(5): e0232879, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32442172

RESUMO

We explore the possibility of using the varnish (Nutallia obscurata) and Manila (Venerupis philippinarum) clams as biomonitors of microplastics (MPs) pollution. A short review is first provided on the use of bivalves for biomonitoring MPs in aquatic ecosystems. From the conclusions drawn from our review we determine if the sediment dwelling varnish and Manila clam could possibly be good choices for this purpose. We sampled 8 intertidal sites located within two distinct regions of coastal British Columbia, Burrard Inlet (5 sites) and Baynes Sound (3 sites). Each intertidal region had its own particular use; within Burrard Inlet, BMP a heavily used marine park, CP, EB, J, and AP, popular local beaches, and within Baynes Sound, Met and NHB, two intertidal regions heavily exploited by the shellfish industry and RU an intertidal region with limited aquaculture activity. Microfragments were recovered from bivalves collected from all intertidal regions except for AP. Microspheres were recovered primarily from bivalves sampled from Baynes Sound at NHB where high numbers of spheres within sediments had previously been reported. BMP and Met had the highest number of particles present within individual clams which were predominantly high density polyethylene (HDPE) and a polypropylene composite (PPC). Both polymers are extensively used by the shellfish industry in all gear types, as well as in industrial and recreational marine activities. The spatial distribution of recovered MPs was indicative of the anthropogenic use of the intertidal region suggesting these bivalves, for microfragments and microspheres, may be suitable as biomonitors and could prove to be useful tools for determining whether reduction policies for plastics use are having a positive effect on their release into marine environments.


Assuntos
Bivalves , Monitoramento Ambiental/métodos , Microplásticos , Poluição da Água , Animais , Aquicultura/instrumentação , Bivalves/química , Bivalves/crescimento & desenvolvimento , Sedimentos Geológicos , Espectrometria de Massas , Microplásticos/análise , Oceanos e Mares , Análise Espacial , Poluição da Água/análise
3.
Food Chem ; 321: 126682, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32278274

RESUMO

An inexpensive and environmental friendly electrochemical sensor based on a glassy carbon electrode (GC) modified with graphene quantum dots (GQDs) and Nafion (NF) has been developed for the determination of Cd(II) and Pb(II) in bivalve mollusks using square wave anodic stripping voltammetry (SWASV). GQDs were characterized by UV-Vis spectroscopy, fluorescence and transmission electronic microscopy (TEM). The modified electrode was evaluated by cyclic voltammetry, scanning electronic microscopy (SEM) and electrochemical impedance spectroscopy (EIS). A linearity of 20-200 µg L-1 was found, with a limit of detection (LOD) of 11.30 µg L-1 for Cd(II) and 8.49 µg L-1 for Pb(II). The proposed methodology was validated with a certified reference material TMDA-64.2. The reproducibility of GC/GQDs-NF for both species had an RSD of less than 10%. The results were compared with ICP-OES. The method was applied in the determination of Cd(II) and Pb(II) in bivalve mollusks samples with excellent results.


Assuntos
Bivalves/química , Cádmio/análise , Chumbo/análise , Animais , Carbono/química , Espectroscopia Dielétrica , Técnicas Eletroquímicas/métodos , Eletrodos , Grafite/química , Limite de Detecção , Pontos Quânticos , Reprodutibilidade dos Testes
4.
J Surg Res ; 251: 262-274, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32197182

RESUMO

BACKGROUND: Myelomeningocele (MMC) is an open neural tube defect of the spinal column. Our laboratory previously introduced a reverse thermal gel (RTG) as the first in situ forming patch for in utero MMC application. To overcome the challenges of anchoring the RTG in the wet amniotic environment to improve MMC coverage, we modified the RTG to mimic the underwater adhesive properties of mussels. We have separated this study into three separate hypotheses-based components: CONCLUSIONS: The DRTG demonstrates increased elasticity, cellular scaffolding properties, and improved MMC coverage in the Grhl3 mouse model. Future studies will be translated to the preclinical ovine model to evaluate this novel gel.


Assuntos
Dopamina/química , Meningomielocele/terapia , Adesivos Teciduais/uso terapêutico , Ureia/uso terapêutico , Animais , Animais Recém-Nascidos , Bivalves/química , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Feminino , Géis , Masculino , Camundongos , Gravidez , Adesivos Teciduais/química , Fatores de Transcrição/genética , Ureia/análogos & derivados , Ureia/síntese química
5.
Mar Environ Res ; 158: 104943, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32217294

RESUMO

Saint-Pierre and Miquelon (SPM) is a small archipelago where instrumental measures based on water column velocity and temperature profiles compiled comprehensive evidence for strong near-diurnal (25.8h) current and bottom temperature oscillations (up to 11.5 °C) which is possibly the largest ever observed - at any frequency - on a stratified mid-latitude continental shelf. The main objective of our study was to identify if Placopecten magellanicus can record on its shell these high frequency environmental variations. To this end, we have tried to identify proxies for water temperature and food availability through development of a new ultra-high resolution LA-ICPMS analyses method capable of resolving shell surface elemental composition with a 10 µm resolution. This method was applied on two shell fragments, both representing the third year of growth and 2015 annual growth period, respectively coming from two environmentally contrasted sites, more (30 m depth) or less (10 m depth) affected by high frequency thermal oscillations. Our results strongly suggest a relationship between phytoplankton biomass and barium incorporation into P. magellanicus shells at both sites. Even if P. magellanicus might present a physiological control of magnesium incorporation, the shape of the two Mg/Ca profiles seems to illustrate that temperature also exerts a control on magnesium incorporation in P. magellanicus shells from SPM. While U/Ca and Mg/Ca profiles show a strong positive correlation for 30 m site shell, suggesting that uranium incorporation in P. magellanicus shell is at least partially temperature dependent. The absence of such correlation for 10 m site shell suggests differences in uranium environmental availability or in P. magellanicus biomineralization between these two sites. The resolution of this new analytical method raises questions about such data interpretation related to P. magellanicus growth dynamics and physiology or individual scale based environmental measurements.


Assuntos
Bivalves , Pectinidae , Oligoelementos , Exoesqueleto , Animais , Bivalves/química , Temperatura , Água
6.
Proc Natl Acad Sci U S A ; 117(13): 7038-7043, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32179672

RESUMO

Paleoclimate research has built a framework for Earth's climate changes over the past 65 million years or even longer. However, our knowledge of weather-timescale extreme events (WEEs, also named paleoweather), which usually occur over several days or hours, under different climate regimes is almost blank because current paleoclimatic records rarely provide information with temporal resolution shorter than monthly scale. Here we show that giant clam shells (Tridacna spp.) from the tropical western Pacific have clear daily growth bands, and several 2-y-long (from January 29, 2012 to December 9, 2013) daily to hourly resolution biological and geochemical records, including daily growth rate, hourly elements/Ca ratios, and fluorescence intensity, were obtained. We found that the pulsed changes of these ultra-high-resolution proxy records clearly matched with the typical instrumental WEEs, for example, tropical cyclones during the summer-autumn and cold surges during the winter. When a tropical cyclone passes through or approaches the sampling site, the growth rate of Tridacna shell decreases abruptly due to the bad weather. Meanwhile, enhanced vertical mixing brings nutrient-enriched subsurface water to the surface, resulting in a high Fe/Ca ratio and strong fluorescence intensity (induced by phytoplankton bloom) in the shell. Our results demonstrate that Tridacna shell has the potential to be used as an ultra-high-resolution archive for paleoweather reconstructions. The fossil shells living in different geological times can be built as a Geological Weather Station network to lengthen the modern instrumental data and investigate the WEEs under various climate conditions.


Assuntos
Bivalves/química , Bivalves/crescimento & desenvolvimento , Clima Extremo , Paleontologia/métodos , Animais
7.
Food Chem ; 320: 126622, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32203840

RESUMO

Water dynamics and protein denaturation in surf clam during heating were studied by the two-dimensional low-field nuclear magnetic resonance (LF-NMR) T1-T2 relaxation technique. A significant change was found for clam around 80 °C and direct visualization of the water state change was provided by the magnetic resonance imaging. Principal components and heatmap analysis revealed that clam treated at 80-100 °C located at different region from those treated at 40-70 °C. The clams heated at 80 °C showed a maximum water holding capability, and significant microstructure change. The differential scanning calorimetry analysis indicated a denaturation of protein when the temperature was over 80 °C. The hardness and chewiness had a maximum value at 80 and 70 °C, respectively. The color parameter L* showed a significant increase when temperature was over 80 °C. This demonstrated that the T1-T2 technique has potential in evaluating water dynamics for surf clam during heating.


Assuntos
Bivalves/química , Animais , Varredura Diferencial de Calorimetria , Temperatura Alta , Espectroscopia de Ressonância Magnética , Desnaturação Proteica , Água/química
8.
J Agric Food Chem ; 68(5): 1427-1435, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31913622

RESUMO

A number of new C-11 hydroxyl metabolites (so-called M-toxins) of paralytic shellfish toxins (PSTs) have been discovered in contaminated shellfish, and trace amounts have also been detected in some strains of PST-producing microalgae. To investigate the chemical conversion and stability of M-toxins, mussel extracts were purified with solid-phase extraction cartridges (Oasis HLB) and Biogel P-2 resin columns and four partially purified M-toxin fractions were stored at different temperatures (-20, 4, and 20 °C) and pH values (3, 4, and 5). The concentrations and profiles of M-toxins in these fractions were analyzed using liquid chromatography coupled with tandem mass spectrometry for 27 weeks. Results further confirmed the chemical conversion pathway M1 → M3 → M5 and determined for the first time two new transformation pathways: M2 → M4 → M6 and neosaxitoxin (NEO) → M10. The half-lives of M1, M2, M4, and M10 were calculated using a first-order degradation kinetics model, which indicated that the degradation of all M-toxins was dependent upon the temperature and pH, increasing with rising temperature and pH. In comparison to M4 and M10, M1 was more sensitive to the temperature, followed by M2. Results suggest that M-toxins should be maintained at a low temperature (-20 °C) and low pH (3) for their prolonged storage. M-toxins were less stable than all of the common analogues of PSTs, which may be beneficial for shellfish to achieve rapid detoxification through transformation of PSTs to M-toxins. These new findings are of significance because they enable further understanding of the metabolism of PSTs and their detoxification mechanisms in contaminated shellfish.


Assuntos
Bivalves/química , Toxinas Marinhas/química , Frutos do Mar/toxicidade , Animais , Cromatografia Líquida de Alta Pressão , Contaminação de Alimentos/análise , Concentração de Íons de Hidrogênio , Toxinas Marinhas/toxicidade , Estrutura Molecular , Frutos do Mar/análise , Espectrometria de Massas em Tandem , Temperatura
9.
Food Chem Toxicol ; 136: 111108, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31899363

RESUMO

The levels of 16 PAHs were determined in the adductor, gills, gonads, hepatopancreas and mantles of the pearl oyster (Pinctada martensii) and the mussel (Perna viridis) collected from coasts of Li'an and Xincun Bays. The levels of ΣPAHs ranged from 597.1 to 2332 ng g-1 d w in the various tissues of bivalves. The pyrolytic source played an important role in the local coastal environment. Significantly higher levels of M-PAHs and H-PAHs were observed in Pinctada martensii than in Perna viridis. The ΣPAHs at different tissues showed the following order from high to low: mantles > hepatopancreas > gonads > gills > adductor. When levels of individual PAHs in the five bivalve tissues have been compared with each other, high correlations have been found (r2 = 0.793-0.975). A general trend was observed that log transformed BSAFs declined with increase of Kow values. The estimated amount of ΣPAHs via ingestion of oyster and mussel varied from 1.35 × 10-2-1.70 × 10-1 and 2.15 × 10-2-1.91 × 10-1 µg kg-1 body weight day-1, respectively. The THQs and CRs calculated for regular consumption of raw bivalves were in the acceptable ranges and may not pose health risk concerns. But for certain population with higher consumption rate for PAHs contaminated bivalves, cautions should be taken for their higher cancer risk.


Assuntos
Bivalves/química , Contaminação de Alimentos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Frutos do Mar/análise , Animais , China , Humanos , Ilhas , Ostreidae/química , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Medição de Risco , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
10.
Nanoscale ; 12(3): 1307-1324, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31907498

RESUMO

The rapid and robust adhesion of marine mussels to diverse solid surfaces in wet environments is mediated by the secreted mussel adhesive proteins which are abundant in a catecholic amino acid, l-3,4-dihydroxyphenylalanine (Dopa). Over the last two decades, enormous efforts have been devoted to the development of synthetic mussel-inspired adhesives with water-resistant adhesion and cohesion properties by modifying polymer systems with Dopa and its analogues. In the present review, an overview of the unique features of various mussel foot proteins is provided in combination with an up-to-date understanding of catechol chemistry, which contributes to the strong interfacial binding via balancing a variety of covalent and noncovalent interactions including oxidative cross-linking, electrostatic interaction, metal-catechol coordination, hydrogen bonding, hydrophobic interactions and π-π/cation-π interactions. The recent developments of novel Dopa-containing adhesives with on-demand mechanical properties and other functionalities are then summarized under four broad categories: viscous coacervated adhesives, soft adhesive hydrogels, smart adhesives, and stiff adhesive polyesters, where their emerging applications in engineering, biological and biomedical fields are discussed. Limitations of the developed adhesives are identified and future research perspectives in this field are proposed.


Assuntos
Adesivos/química , Materiais Biomiméticos/química , Bivalves/química , Hidrogéis/química , Proteínas/química , Animais
11.
Environ Sci Pollut Res Int ; 27(2): 1734-1751, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31755057

RESUMO

The present study aimed to evaluate the biochemical status of Venerupis decussata collected seasonally from two Tunisian coastline lagoons (Ghar El Melh and Boughrara) submitted to different anthropogenic levels. Trace elements were significantly higher in clams from Boughrara, especially during the warm season. Fatty acids, proximate compositions, and nutritional value of both clam populations were higher, appearing to be the best for human consumption principally during the spring season. The principal component analysis was determined, including phospholipids and reserve lipids, revealing a great variation with the exogenous and endogenous factors. Generally, clams from Boughrara had a significant alteration in biochemical composition principally due to the anthropogenic levels and physicochemical fluctuation of this lagoon. Our results reflected the healthy benefit of clam consumption and the use of energy reserves and essential fatty acids as a great biomarker to assess ecological risk in lagoons and other coastal ecosystems.


Assuntos
Bivalves/química , Ecossistema , Valor Nutritivo , Alimentos Marinhos , Animais , Biomarcadores , Monitoramento Ambiental , Ácidos Graxos/análise , Humanos , Estações do Ano , Oligoelementos/análise , Tunísia
12.
Macromol Rapid Commun ; 41(2): e1900450, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31778252

RESUMO

The latest generation of wearable devices features materials that are flexible, conductive, and stretchable, thus meeting the requirements of stability and reliability. However, the metal conductors that are currently used in various equipments cannot achieve these high performance expectations. Hence, a mussel-inspired conductive hydrogel (HAC-B-PAM) is prepared with a facile approach by employing polyacrylamide (PAM), dopamine-functionalized hyaluronic acid (HAC), borax as a dynamic cross-linker agent, and Li+ and Na+ as conductive ions. HAC-B-PAM hydrogels demonstrate an excellent stretchability (up to 2800%), high tensile toughness (42.4 kPa), self-adhesive properties (adhesion strength to porcine skin of 49.6 kPa), and good self-healing properties without any stimuli at room temperature. Furthermore, the fabricated hydrogel-based strain sensor is sensitive to deformation and can detect human body motion. Multifunctional hydrogels can be assembled into flexible wearable devices with potential applications in the field of electronic skin and soft robotics.


Assuntos
Adesivos/química , Bivalves/química , Hidrogéis/química , Dispositivos Eletrônicos Vestíveis , Resinas Acrílicas/química , Animais , Técnicas Biossensoriais , Boratos/química , Dopamina/química , Elasticidade , Condutividade Elétrica , Humanos , Ácido Hialurônico/química , Íons/química , Movimento (Física) , Resistência ao Cisalhamento
13.
Environ Sci Pollut Res Int ; 27(4): 3715-3725, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30949944

RESUMO

Margaritifera margaritifera is a critically endangered species in Europe. Among the causes explaining its decline, metal pollution had never been deeply studied. Thus, an ecotoxicological investigation was developed on this species which comes from the Dronne River (South-West of France). Cadmium (Cd) exposure of mussels at 2 and 5 µg/L for 7 days was conducted to test their vulnerability to this metal, and also the potential endocrine disruption power of Cd. Morphometric analyses, gonad histological observations, metal bioaccumulation, metallothionein (MTs) production, measures of malondialdehyde (MDA), and finally quantitative relative expression analysis of genes involved in various metabolic functions were performed.The main results showed Cd accumulation increasing in a dose-dependent manner, especially in the gills. The same trend was observed for gene expression relative to oxidative stress. Histological analysis of the gonads highlighted a predominance of hermaphrodite individuals, but after 7 days of exposure to Cd, the percentage of female was largely increased compared with controls, from 17 to 33%. These results demonstrate the endocrine disruption effect of Cd on freshwater pearl mussels.The pearl mussel Margaritifera margaritifera is sensitive to cadmium since the metallothioneins are poorly induced, gene expression reveals oxidative stress, and gonads tend to be feminized.


Assuntos
Bivalves , Cádmio , Animais , Bivalves/química , Cádmio/análise , Cádmio/química , Europa (Continente) , França , Água Doce
14.
Food Chem ; 308: 125650, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31655477

RESUMO

This study aimed at investigating the formation and accumulation of 16 reactive aldehydes in clam (Ruditapes philippinarum) during oil frying in both the tissue and the oil using an HPLC-ESI-MS/MS methodology. After processing, the accumulation of acrolein, crotonaldehyde, pentanal, trans-2-hexenal, hexanal, trans, trans-2,4-heptadienal, heptanal, nonanal, trans, trans-2,4-decadienal and 4-hydroxy-2-nonenal was most noticeable in both fried clam and frying oil. Most of the aldehyde species showed a time- and temperature-dependent manner of formation and accumulation during frying due to continuous oxidative degradation under conditions employed. However, several species of aldehyde such as acrolein and trans-2-pentenal slightly decreased at higher temperatures and/or longer frying times, which may be due to the imbalance toward disappearance of aldehydes resulting from their evaporation under the extreme conditions. Presence of natural polyphenols in bamboo leaves significantly prevented the formation of aldehydes in both fried clam and frying oil due to their antioxidant activity (P < 0.05).


Assuntos
Aldeídos/química , Bivalves/química , Animais , Cromatografia Líquida de Alta Pressão , Culinária , Temperatura Alta , Oxirredução , Espectrometria de Massas em Tandem
15.
Food Chem ; 309: 125575, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31685369

RESUMO

Recent reports showed that patients could be sensitized to fish tropomyosin (TM), who exhibited clinical symptoms. However, little information is available on differences in TM immune cross-reactivity among fish, shrimp and clam. Moreover, allergenicity might change during the food processing owing to the change of protein structure. In this study, we developed a nonthermal extraction technique to purified TM, IgG/IgE binding, cross-reactivity and structures were compared. Results showed that raw and boiled fish-TM were not cross reactive and had weak recognition of shrimp, while, shrimp-TM and clam-TM were cross reactive. The ELISA further confirmed that fish-TM was not able to trigger allergic immune response in shrimp sensitive subjects, while, surface hydrophobicity of fish-TM was higher. The study demonstrated that fish-TM, being with high sequence similarity, did not have cross-reactivity with shrimp and clam-TM. They could have a variable degree of IgE binding depending on subject sensitivity and allergenicity.


Assuntos
Hipersensibilidade Alimentar , Alimentos Marinhos/análise , Tropomiosina/imunologia , Adulto , Alérgenos/imunologia , Animais , Bivalves/química , Bivalves/metabolismo , Criança , Pré-Escolar , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina E , Imunoglobulina G , Masculino , Pessoa de Meia-Idade , Penaeidae/química , Penaeidae/metabolismo , Perciformes/metabolismo , Adulto Jovem
16.
Food Chem ; 311: 125907, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31865115

RESUMO

The increasing global population poses a huge challenge to food security, especially in terms of providing adequate sustainable and affordable high quality lipids. This article reviews the sources of natural omega-3 LC-PUFA and identifies the future direction for producing high quality lipids to meet growing market demands. Generally, bivalve lipids are high quality source of lipids that are beneficial to human health, regardless of species and habitat. There is also reason to believe that the development of bivalve farming worldwide, selective breeding of bivalves to increase the accumulation of omega-3 LC-PUFA and practising efficient usage of bivalve lipids can meeting some, if not all, of the growing demand for omega-3 LC-PUFA. Such information will aid to establish a promising source of high quality natural omega-3 LC-PUFA and ensure that all consumers have access to sufficient omega-3 LC-PUFA at an affordable price to support a healthier and balanced diet.


Assuntos
Bivalves/química , Ácidos Graxos Ômega-3/análise , Animais , Bivalves/crescimento & desenvolvimento , Abastecimento de Alimentos , Humanos
17.
Macromol Rapid Commun ; 41(2): e1900533, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31856366

RESUMO

Mussel-inspired polymers attract much research interest due to their potential as effective adhesives. In this work, a new kind of mussel-inspired polymer, poly(dopamine phosphonate-co-PEGMA), is prepared via a one-pot multicomponent polymerization system. The multicomponent polymerization system refers to a combination of multicomponent Kabachnik-Fields (KF) reaction and reversible addition-fragmentation chain transfer (RAFT) polymerization system. Reactants are converted to dopamine phosphonate monomers in situ through the KF reaction and polymerized simultaneously along with poly(ethylene glycol methyl ether) methacrylate (PEGMA) co-monomers by the RAFT process in a one-pot operation. Target polymers with dopamine phosphonate as side groups and well-defined polymer structures are thus facilely and successfully prepared. Afterwards, a series of polymers with various ratios of dopamine phosphonates as well as the crosslinked polymer analogues are prepared. Benefiting from the dopamine phosphonate side groups, aqueous solutions of those polymers show potential as effective adhesives in both dry and wet conditions, and their adhesive strengths are highly related to ratios of dopamine phosphonates in the polymers. Those polymers are non-cytotoxic and show strong bonding affinities on various substrates including metals, polymers, and bovine bones, suggesting their potential as environmentally friendly general adhesives in broad areas.


Assuntos
Bivalves/química , Dopamina/química , Metacrilatos/química , Polietilenoglicóis/química , Polímeros/química , Adesivos , Animais , Organofosfonatos/química , Polimerização , Resistência ao Cisalhamento
18.
Food Chem ; 312: 126053, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31884298

RESUMO

To understand the delicious taste of the clam M. meretrix Linnaeus, the putative umami peptides from the aqueous extract of the cooked clam were obtained by ultrafiltration, gel filtration chromatography, and reversed-phase high-performance liquid chromatography. The isolated peptide fraction with the most intense umami taste was screened by sensory and electronic tongue analysis. Seven novel peptides, GLLPDGTPR, RPNPFENR, STMLLESER, ANPGPVRDLR, QVAIAHRDAK, VLPTDQNFILR, and VTADESQQDVLK, were identified and synthesized to verify their taste characteristics. The taste activity prediction and the sensory evaluation of the synthetic peptides revealed that those peptides were umami and umami-enhancing peptides. Docking of the synthesized peptides with the umami taste receptor T1R1/T1R3 indicated that the peptides could enter the binding pocket in the Venus flytrap domain of the T1R3 cavity, wherein Asp196 and Glu128 may play key roles in the synergism of umami taste and hydrogen bonding and electrostatic interactions are important interaction forces.


Assuntos
Bivalves/química , Peptídeos/química , Paladar , Animais , Bivalves/metabolismo , Cromatografia em Gel , Nariz Eletrônico , Simulação de Acoplamento Molecular , Peptídeos/metabolismo
19.
Molecules ; 24(24)2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31817348

RESUMO

The aim of this study was to explore the immunomodulatory effects of the Meretrix meretrix oligopeptide (MMO, QLNWD) in cyclophosphamide (CTX)-induced immune-deficient mice. Compared to untreated, CTX-induced immune-deficient mice, the spleen and thymus indexes of mice given moderate (100 mg/kg) and high (200 mg/kg) doses of MMO were significantly higher (p < 0.05), and body weight loss was alleviated. Hematoxylin-eosin (H&E) staining revealed that MMO reduced spleen injury, thymus injury, and liver injury induced by CTX in mice. Furthermore, MMO boosted the production of immunoglobulin G (IgG) and hemolysin in the serum and promoted the proliferation and differentiation of spleen T-lymphocytes. Taken together, our findings suggest that MMO plays a vital role in protection against immunosuppression in CTX-induced immune-deficient mice and could be a potential immunomodulatory candidate for use in functional foods or immunologic adjuvants.


Assuntos
Bivalves/química , Imunodeficiência de Variável Comum , Fatores Imunológicos , Oligopeptídeos , Linfócitos T , Animais , Imunodeficiência de Variável Comum/tratamento farmacológico , Imunodeficiência de Variável Comum/imunologia , Imunodeficiência de Variável Comum/patologia , Fatores Imunológicos/química , Fatores Imunológicos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Especificidade de Órgãos/efeitos dos fármacos , Especificidade de Órgãos/imunologia , Linfócitos T/imunologia , Linfócitos T/patologia
20.
Mar Pollut Bull ; 145: 153-160, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590772

RESUMO

As a global pollutant, microplastics have attracted attention from the public and researchers. However, the lack of standard and time-saving methods for analysis has become one of the bottlenecks in microplastics research. Here, we demonstrate TGA coupled to FTIR to identify and quantify certain microplastics in environment. Samples were pyrolyzed in TGA and the pyrolysis gases were analyzed by FTIR. Combining TGA and FTIR data adds discriminatory power as temperature profiles and absorption spectra differ among several common plastics. To quantify on a mass basis, we calibrated on characteristic IR peaks at temperatures of maximum weight loss for individual polymers. The method can distinguish PVC, PS and was validated by spiking samples with known quantities of microplastics. The result of field sample experiments showed that TGA-FTIR can be used to identify and quantify PVC and PS in bivalves, seawater and soil. And the method may be applicable to environmental samples.


Assuntos
Plásticos/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Termogravimetria/métodos , Poluentes Químicos da Água/análise , Animais , Bivalves/química , China , Monitoramento Ambiental/métodos , Plásticos/química , Polímeros/análise , Polímeros/química , Reprodutibilidade dos Testes , Água do Mar/química , Poluentes do Solo/análise , Poluentes do Solo/química , Poluentes Químicos da Água/química
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