课程文献中心 更多>>

关键词： Biopolymer   Characterization   Molecular structure   Spectroscopy   Densitometry   Fishery resources  

摘要： Collagenous biopolymers can be analyzed using physic-chemical, densitometric, and spectroscopic analysis to obtain their main characteristics, aiming at their biotechnological manipulation. Collagen extracted from fishery resources is a product of high added value, with potential use in food, biopharmaceutical and cosmetic industries. Some factors make the use of the polymer from fishery resources promising, such as: high availability;greater ontogenetic distance between fish and humans;absence of sociocultural barriers;and absence of toxicity. The collagen extraction method (acid-soluble, pepsin-soluble, electrodialysis, ultrasound, isoelectric precipitation) will directly influence its properties. Thus, this work aims to provide an overview of the extraction methods, characterization techniques (solubility, zeta potential, viscosity, thermogravimetry, differential scanning calorimetry, SDS-PAGE, densitometry, gel strength, centesimal composition, color, aminogram, hydroxyproline determination, X-ray diffraction, circular dichroism, ultraviolet, Raman, and FTIR spectroscopy), and potential analysis with a focus on aquaculture and fisheries sources, through a compilation of scientific information that can be useful to guide aquatic biotechnology professionals, considered that its properties are similar to collagen extracted from mammals. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Biochemical biomarkers   Histopathology   Oxidative stress   Mixtures   Pesticides  

摘要： The widespread use of agrochemicals results in the exposure of the general human population, including children, to several of these chemicals simultaneously. In the present preclinical study, it was investigated the hepatic damages caused by exposure to acephate, carbendazim and mancozeb when administered alone or in different combinations (binary and ternary). Juvenile male Wistar rats were exposed to agrochemicals from postnatal day 53, by gavage. The doses of agrochemicals applied here were determined from previous studies whose results showed no signs of systemic toxicity. All exposures provoked a significant increase in DNA damage (except for acephate alone) and activation of the xenobiotic biotransformation system (except for the ternary mixture). Interestingly, the ternary mixture did not exhibit an exacerbation in adverse effects caused by agrochemicals isolated or in binary combination, even though they are sharing genotoxicity damage induction as a common toxicity pathway. Conversely, some effects observed for isolated or binary combinations of agrochemicals were not observed for ternary combination, suggesting a chemical interaction that could imply antagonism character. Using a multivariate data analysis approach, exposure to isolated agrochemicals were related to a group of adverse effects characterized by hepatic lesion and the attempt of the tissue to mobilize defense cells and increase mitotic rates to minimize damages. Binary mixtures also share similarities in relation to the effects they exhibited, mainly a moderate to high increase in the GST activity and in histopathological alterations suggesting that binary combinations trigger an increased response of the mechanism of xenobiotics biotransformation. Together, obtained results bring important insights regarding adverse effects and possible interaction of the three agrochemicals whose residues are commonly detected in agro-food products.

关键词： Oxidative stress   Bivalve   Metal detoxification   Metallomics  

摘要： Marine bivalves have been widely applied as environmental contamination bioindicators, although studies concerning tropical species are less available compared to temperate climate species. Assessments regarding Perna perna mytilid mussels, in particular, are scarce, even though this is an extremely important species in economic terms in tropical countries, such as Brazil. To this end, Perna perna mytilids were sampled from two tropical bays in Southeastern Brazil, one anthropogenically impacted and one previously considered a reference site for metal contamination. Gill metallothionein (MT), reduced glutathione (GSH), carboxylesterase (CarbE) and lipid peroxidation (LPO) were determined by UV-vis spectrophotometry, and metal and metalloid contents were determined by inductively coupled plasma mass spectrometry (ICP-MS). Metalloprotein metal detoxification routes in heat-stable cellular gill fractions were assessed by size exclusion high performance chromatography (SEC-HPLC) coupled to an ICP-MS. Several associations between metals and oxidative stress endpoints were observed at all four sampling sites through a Principal Component Analysis. As, Cd, Ni and Se contents, in particular, seem to directly affect CarbE activity. MT is implicated in playing a dual role in both metal detoxification and radical oxygen species scavenging. Differential SEC-HPLC-ICP-MS metal-binding profiles, and, thus, detoxification mechanisms, were observed, with probable As-, Cuand Ni-GSH complexation and binding to low molecular weight proteins. Perna perna mussels were proven adequate tropical bioindicators, and further monitoring efforts are recommended, due to lack of data regarding biochemical metal effects in tropical species. Integrated assessments, as performed herein demonstrate, are invaluable in evaluating contaminated aquatic environments, resulting in more accurate ecological risk assessments.

关键词： Ionic liquids   Cytotoxicity   Membrane damage   Biochemical alteration   FTIR  

摘要： As an alternative to volatile organic solvents, ionic liquids (ILs) are known as "green solvents", and widely used in industrial applications. However, due to their high solubility and stability, ILs have tendency to persist in the water environment, thus having potential negative impacts on the aquatic ecosystem. For assessing the environmental risks of ILs, a fundamental understanding of the toxic effects and mechanisms of ILs is needed. Here we evaluated the cytotoxicity of 1-methyl-3-decylimidazolium chloride ([C(10)mim]Cl) and elucidated the main toxic mechanism of [C(10)mim]Cl in human cervical carcinoma (Hela) cells. Microstructural analysis revealed that [C(10)mim]Cl exposure caused the cell membrane breakage, swollen and vacuolated mitochondria, and spherical cytoskeletal structure. Cytotoxicity assays found that [C(10)mim]Cl exposure increased ROS production, decreased mitochondrial membrane potential, induced cell apoptosis and cell cycle arrest. These results indicated that [C10mim]Cl could induce damage to cellular membrane structure, affect the integrity of cell ultrastructure, cause the oxidative damage and ultimately lead to the inhibition of cell proliferation. Moreover, alterations of biochemical information including the increased ratios of unsaturated fatty acid and carbonyl groups to lipid, and lipid to protein, and the decreased ratios of Amide I to Amide II, and alpha-helix to beta-sheet were observed in [C(10)mim]Cl treated cells, suggesting that [C(10)mim]Cl could affect the structure of membrane lipid alkyl chain and cell membrane fluidity, promote the lipid peroxidation and alter the protein secondary structure. The findings from this work demonstrated that membrane structure is the key target, and membrane damage is involved in [C(10)mim]Cl induced cytotoxicity.

关键词： Gastric evacuation   Blood biochemistry   Intestinal digestive enzyme   Appetite-related genes  

摘要： The proportion of remaining stomach meal (PSR), gastric evacuation model, serum cortisol and glucose levels, intestinal lipase, amylase, and chymotrypsin activities and the expression levels of neuropeptide Y (npy), orexin (ore) and leptins (lepa, lepb) of the hybrid grouper (Epinephelus moara female x E. lanceolatus male) during gastric evacuation were evaluated to determine the optimal feeding interval. Results showed that PSR significantly decreased by more than 60%, 70%, and 90% at postprandial 6 h, 9 h and 12 h, respectively. The cubic root curve was the most supported model and fitted all PSR data. The cortisol and glucose levels were significantly varied, and the highest values were obtained at postprandial 6 h. Cortisol and the glucose levels then gradually decreased from postprandial 9 h to postprandial 12 h. Intestinal lipase and chymotrypsin activities showed similar results to cortisol, whereas the amylase activity was not significantly different during gastric evacuation. The hypothalamic npy and ore mRNA levels were gradually up-regulated within postprandial 6 h, and then significantly down-regulated from postprandial 9 to postprandial 12 h. By contrast, hepatic lepa and lepb mRNA levels remained high levels within postprandial 6 h and significantly decreased from postprandial 9 to postprandial 12 h. These results indicated that food digestion in the intestine peaked at postprandial 6 h. Afterward, appetite returned and fully recovered at about postprandial 12 h. Therefore, on the basis of the aforementioned results and considering the fish management, postprandial 12 h is the optimal feeding interval of hybrid grouper (Epinephelus moara female x E. lanceolatus male). This feeding interval offers potential savings in time and labor spent in cultivating hybrid grouper in captivity.

关键词： Iron toxicity   Physiological responses   Ammonia excretion   Rh glycoprotein   Gene expression   Energy budget  

摘要： Iron overload is a significant water quality issue in many parts of the world. Therefore, we evaluated the potential toxic effects of waterborne elevated iron on largemouth bass (Micropterus salmoides), a highly valued sport and aquaculture fish species. First, a 96 h-LC50 toxicity assay was performed to understand the tolerance limit of this species to iron;and was determined to be 22.07 mg/L (as Fe3+). Thereafter, to get a better insight on the fish survival during long-term exposure to high environmental iron (HEI) (5.52 mg/L, 25% of the determined 96 h-LC50 value), a suite of physio-biochemical, nitrogenous metabolic and ion-regulatory compensatory responses were examined at 7, 14, 21 and 28 days. Results showed that oxygen consumption dropped significantly at 21 and 28 days of HEI exposure. Ammonia excretion rate (J(amm)) was significantly inhibited from day 14 and remained suppressed until the last exposure period. The transcript concentration of Rhesus glycoproteins Rhcg2 declined;likely diminishing ammonia efflux out of gills. These changes were also reflected by a parallel increment in plasma ammonia levels. Under HEI exposure, ion-balance was negatively affected, manifested by reduced plasma [Na+] and parallel inhibition in branchial Na+/K+-ATPase activity. Muscle water content was elevated in HEI-exposed fish, signifying an osmo-regulatory compromise. HEI exposure also increased iron burden in plasma and gills. The iron accumulation pattern in gills was significantly correlated with a suppression of J(amm), branchial Rhcg2 expression and Na+/K+-ATPase activity. There was also a decline in the glycogen, protein and lipid reserves in the hepatic tissue from 14 days, 28 days and 21 days, respectively. Overall, we conclude that sub-lethal chronic iron exposure can impair normal physio-biochemical and ion-regulatory functions in largemouth bass. Moreover, this data set can be applied in assessing the environmental risk posed by a waterborne iron overload on aq

关键词： GH19 chitinase   Enzymatic conversion   Anti-fungi  

摘要： Chitinases play crucial roles in enzymatic conversion of chitin and biocontrol of phytopathogenic fungi. Herein, a chitinase of glycoside hydrolase (GH) family 19, SaChiB, was cloned from Streptomyces alfalfae ACCC 40021 and expressed in Escherichia coli BL21(DE3). The purified SaChiB displayedmaximal activities at 45 degrees C and pH 8.0, and showed good stability up to 55 degrees C and in the range of pH 4.0-11.0, respectively. It exhibited substrate specificity towards chitin and chitooligosaccharides (degree of polymerization 3-6) with the endo-cleavage manner. In combination with the N-acetyl hexosaminidase SaHEX, it yielded a conversion rate of 95.2% from chitin powder to N-acetyl-D-glucosamine in 8 h and a product purity of >98.5%. Furthermore, the enzyme strongly inhibited the growth of tested pathogenic fungi. These results indicated that SaChiB has the great potential for applications in the conversion of raw chitinous waste in industries as well as the biocontrol of fungal diseases in agriculture. (C) 2020 Published by Elsevier B.V.

关键词： Epinephelus fuscoguttatus   Epinephelus polyphekadion   Feed fat   Biochemical  

摘要： The growth of teleost fish can be enhanced by several means. A fat-enriched feed provides substantial energy for fish in aquaculture. However, fat is an expensive feed component and one of the highest cost components of the feed for cultured species in the aquaculture industry. Therefore, in recent years, nutritionists increasingly focus on improving the fat efficacy of feed components utilized in commercial feeds. To achieve this, precise, comprehensive, and homogeneous analytical procedures are required to quantify fat in feed components. This study assessed the influence of the feed fat level on growth performance, body composition, and serum biochemical indices of the 8 weeks old juvenile hybrid grouper (8 cm) with average body weight of 7.2 g. The results show that the level of feed fat has no substantial effect on the survival rate of the hybrid grouper, which indicates that hybrid grouper juveniles can tolerate high feed fat levels. In addition, the results also show that increasing the level of feed fat can increase the growth rate of fish and feed efficiency, while decreasing their ammonia nitrogen excretion rate. The suitable dietary fat level of hybrid grouper was identified to be 9.72-10.28%. This offers valuable insight into the effects of the feed fat level on the growth performance of the hybrid grouper, which can inform the culture of other species in aquaculture.

关键词： Graphene oxide   Eisenia fetida   Antioxidant enzymes   Lysosomal membrane   DNA damage  

摘要： With the growing production and use of carbon nanomaterials (CNMs), the risk of their releases to the environment has drawn much attention. However, their potential effect on soil invertebrates has not yet been systematically assessed. Herein, the toxic effects of graphene oxide (GO) on earthworms (Eisenia fetida) were thoroughly investigated. Exposure to different doses of GO (0, 5, 10, 20, and 30 g kg(-1)) was conducted for 7, 14, 21, and 28 days. The results showed that enzymatic activity was stimulated at the early stages of exposure (7 days and 14 days) and inhibited after 14 days for catalase (CAT) and after 21 days for peroxidase (POD) and superoxide dismutase (SOD), especially at high GO doses. The content of MDA showed an increasing trend over the whole exposure period and was significantly elevated by GO from 21 days except at the dose of 5 g kg(-1) on day 21. Lysosomal membrane stability and DNA damage presented dose- and time-dependent relationships. Graphene oxide remarkably decreased lysosomal membrane stability except at the dose of 5 g kg(-1) on day 7. The tail DNA%, tail length and olive tail moment increased with increasing GO dose throughout the exposure duration, reaching maximum values at the end of exposure (28 days). These findings suggest that GO induces oxidative stress and genotoxicity in Eisenia fetida, resulting in lipid peroxidation, decreased lysosomal membrane stability and DNA damage. Therefore, attention should be paid to the potential pollution and risk associated with graphene oxide application. The results can provide valuable information for environmental safety assessment of graphene nanomaterials in soil. (C) 2020 Elsevier Ltd. All rights reserved.