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1.
J Fish Biol ; 102(5): 1049-1066, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36794305

RESUMO

In the northern Gulf of St. Lawrence (nGSL), redfish (Sebastes mentella and Sebastes fasciatus combined) are at record levels of abundance following the strong recruitment of three consecutive cohorts in 2011-2013 and have become by far the most abundant demersal fish in the region. Understanding redfish trophic relationships is essential for the effective management and conservation of species in the nGSL ecosystem. To date, description and quantification of redfish diet in the region have been restricted to conventional stomach content analysis (SCA). Using analysis of fatty acid (FA) profiles as complementary dietary tracers, the authors conducted multivariate analyses on 350 livers of redfish which were collected in combination with stomach contents during a bottom-trawl scientific survey in August 2017. The predator FA profiles were compared to those of eight different redfish prey types identified as dietary important with SCA. Results suggested similitude between SCA and FA results, with zooplankton prey being more related to small (<20 cm) and medium (20-30 cm) redfish (16:1n7, 20:1n?, 22:1n9 and 20:5n3) than large (≥30 cm) ones, whereas shrimp prey seemed more related to large redfish size classes (18:2n6 and 22:6n3) relative to the small and medium ones. Although the SCA offers a glimpse in the diet only based on the most recently consumed prey, analysis of FA profiles provides a mid-term view indicating pelagic zooplankton consumption on calanoid copepod and confirming high predation pressure on shrimp. This study constitutes the first attempt of combining FA with SCA to assess the diet of redfish, highlights the benefits of FA as a qualitative tool and suggests improvements for future studies.


Assuntos
Conteúdo Gastrointestinal , Perciformes , Animais , Conteúdo Gastrointestinal/química , Ecossistema , Ácidos Graxos/análise , Peixes , Dieta/veterinária
2.
Sci Total Environ ; 779: 146316, 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34030258

RESUMO

Spillages at sea of diluted bitumen (dilbit) from oil sands have received little attention until now. To our best knowledge, there are no reports on the impact of a severe exposure to dilbit on the Blue mussel (Mytilus edulis). In this study, adult Blue mussels were exposed to one conventional crude oil (Heidrun) and two dilbits (Cold Lake Blend and Access Western Blend) for a period of 7 days in an ice-covered environment and then maintained for three months until the spawning season. The exposed mussels were monitored for aromatic hydrocarbon bioaccumulation, physiological energetic budget, cellular stress, byssus production and gametogenesis. In spring, spawning was induced to characterize breeding success. Bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) was detected after three days of exposure, with higher concentrations of PAHs associated to the conventional oil (5.49 ± 0.12 µg·g-1 d.w.) compared to both dilbits (0.91 ± 0.02 µg·g-1; 0.51 ± 0.03 µg·g-1 d.w.). Despite a fast depuration rate and a good resilience of the exposed mussels, significant negative effects were observed at the cellular, physiological and fitness levels, especially in offspring. Our results suggest a higher toxicity of the diluted bitumen compared to the conventional crude despite the lower bioaccumulation of total PAHs. Dilbit treatments caused evident negative transgenerational effects on unexposed F1 generation.


Assuntos
Mytilus edulis , Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Animais , Hidrocarbonetos , Gelo , Campos de Petróleo e Gás , Petróleo/análise , Petróleo/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes Químicos da Água/toxicidade
3.
Biochim Biophys Acta Biomembr ; 1863(9): 183642, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34000261

RESUMO

This work investigates the potential probiotic effect of marennine - a natural pigment produced by the diatom Haslea ostrearia - on Vibrio splendidus. These marine bacteria are often considered a threat for aquaculture; therefore, chemical antibiotics can be required to reduce bacterial outbreaks. In vivo2H solid-state NMR was used to probe the effects of marennine on the bacterial membrane in the exponential and stationary phases. Comparisons were made with polymyxin B (PxB) - an antibiotic used in aquaculture and known to interact with Gram(-) bacteria membranes. We also investigated the effect of marennine using 31P solid-state NMR on model membranes. Our results show that marennine has little effect on phospholipid headgroups dynamics, but reduces the acyl chain fluidity. Our data suggest that the two antimicrobial agents perturb V. splendidus membranes through different mechanisms. While PxB would alter the bacterial outer and inner membranes, marennine would act through a membrane stiffening mechanism, without affecting the bilayer integrity. Our study proposes this microalgal pigment, which is harmless for humans, as a potential treatment against vibriosis.


Assuntos
Microalgas/química , Fenóis/química , Vibrio/química , Deutério , Espectroscopia de Ressonância Magnética , Fósforo
4.
Rapid Commun Mass Spectrom ; 26(10): 1165-74, 2012 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-22499191

RESUMO

RATIONALE: A method has been developed for the quantitation of isotopic labeling of proteins using liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the application of protein nuclear magnetic resonance (NMR) studies. NMR relies on specific isotopic nuclei, such as (13)C and (15)N, for detection and, therefore, isotopic labeling is an important sample preparation step prior to in-depth structural characterization of proteins. The goal of this study was to develop a robust quantitative assay for assessing isotopic labeling in proteins while retaining information on the extent of labeling for individual amino acids. METHODS: Complete digestion of proteins by acid hydrolysis was followed by derivatization of free amino acids with 6-aminoquinolyl N-hydroxysuccinimidyl carbamate (AQC) forming derivatives having identical MS/MS fragmentation behavior. Precursor ion scanning on a hybrid quadrupole-linear ion trap platform was used for amino acid analysis and determining isotopic labeling of proteins. RESULTS: Using a set of isotope-labeled amino acid standards mixed with their unlabeled counterparts, the method was validated for accurately measuring % isotopic contribution. We then applied the method for determining the (13)C isotopic content of algal proteins during a feeding study using (13)C(6)-glucose- or (13)C-bicarbonate-supplemented culture media as well as the level of labeling in mussel byssal threads obtained after feeding with labeled algae. CONCLUSIONS: This method is ideally suited for assessing the extent of protein labeling prior to NMR studies, where the isotopic labeling is a determining factor in the quality of resulting protein spectra, and can be applied to a multitude of different biological samples.


Assuntos
Proteínas de Algas/química , Aminoácidos/análise , Cromatografia Líquida/métodos , Marcação por Isótopo/métodos , Espectrometria de Massas em Tandem/métodos , Proteínas de Algas/análise , Proteínas de Algas/metabolismo , Aminoácidos/química , Aminoácidos/metabolismo , Isótopos de Carbono/análise , Isótopos de Carbono/metabolismo , Modelos Lineares , Espectroscopia de Ressonância Magnética , Microalgas/metabolismo , Reprodutibilidade dos Testes
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