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1.
Sci Total Environ ; 719: 137396, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32143096

RESUMO

Composite beads (APEI*), obtained by the controlled interaction of algal biomass with PEI, followed by ionotropic gelation and crosslinking processes using CaCl2/glutaraldehyde solution, constitute efficient supports for metal binding. The quaternization of algal/PEI beads (Q-APEI*) significantly increases the sorption properties of the composite beads (APEI*) for As(V). The materials are characterized by SEM/EDX, TGA, BET, elemental analysis, FTIR, XPS, and titration. The sorption of As(V) is studied in function of pH while sorption mechanism is discussed in function of metal speciation and surface characteristics of the sorbent. Optimum sorption occurs at pH close to 7. Fast uptake kinetics, correlated to textural properties are successfully fitted by pseudo-first order rate equation and the Crank equation (for resistance to intraparticle diffusion); equilibrium is reached with 45-60 min. The Langmuir equation finely fits sorption isotherms; maximum sorption capacity reaches 1.34 mmol As g-1. Arsenic can be completely eluted using 0.5 M CaCl2/0.5 M HCl solutions; the sorbent maintains high sorption and desorption efficiencies for a minimum of 5 cycles. The sorbent is tested for the removal of As(V) from mining effluents containing high concentration of iron and traces of zinc. At pH 3, the sorbent shows remarkable selectivity for As(V) over Fe. After controlling the initial pH to 5, a sorbent dosage of 2 g L-1 is sufficient for achieving the complete recovery of As(V) from mining effluent (corresponding to initial concentration of 1.295 mmol As L-1).


Assuntos
Polietilenoimina/química , Adsorção , Arsênico , Concentração de Íons de Hidrogênio , Cinética , Soluções , Estramenópilas , Água , Poluentes Químicos da Água
2.
Bioresour Technol ; 302: 122893, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32018087

RESUMO

Two-step procedure with the initial aqueous extraction from raw microalgae Nannochloropsis oculata and secondary organic solvent extraction from vacuum dried (VD) microalgae were applied for selective recovery of bio-molecules. The effects of preliminary aqueous washing and high voltage electrical discharges (HVED, 40 kV/cm, 4 ms pulses) were tested. The positive effects of HVED treatment and washing on selectivity of aqueous extraction of ionics and other water-soluble compounds (carbohydrates, proteins and pigments) were observed. Moreover, the HVED treatment allowed improving the kinetic of vacuum drying, and significant effects of HVED treatment on organic solvent extraction of chlorophylls, carotenoids and lipids were determined. The proposed two-step procedure combining the preliminary washing, HVED treatment and aqueous/organic solvents extraction steps are useful for selective extraction of different bio-molecules from microalgae biomass.


Assuntos
Microalgas , Estramenópilas , Biomassa , Eletricidade , Solventes
3.
Sci Total Environ ; 714: 136737, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-31982752

RESUMO

This study investigated the response of three toxic harmful algal blooms (HABs) species, Heterosigma akashiwo, Chattonella marina, and Alexandrium tamarense to coastal invasive plant, Spartina alterniflora. In this study, the growth of three HABs species were suppressed significantly by S. alterniflora extracts, showing a dose-response relationship. The raphidophyte H. akashiwo and C. marina exhibited higher inhibitory response with EC50,7d decreased by 14% and 75% as compared to the dinoflagellate A. tamarense. C. marina was the most sensitive among the three species. S. alterniflora extracts disrupted algal cellular integrity and photosynthesis. Furthermore, the extracellular organic matters were detected by fluorescence excitation-emission matrix. Algal metabolites, protein-like substances (tyrosine-like peak and tryptophan-like peak) decreased as time prolonged and the humic-like substances (UVA marine humic-like peak) increased when algal cells were exposed to S. alterniflora extracts. These results provide new insights to the inhibition mechanism of S. alterniflora extracts on HABs species.


Assuntos
Dinoflagelados , Poaceae , Proliferação Nociva de Algas , Estramenópilas
4.
Dis Aquat Organ ; 137(2): 145-157, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31942860

RESUMO

Seagrasses create foundational habitats in coastal ecosystems. One contributing factor to their global decline is disease, primarily caused by parasites in the genus Labyrinthula. To explore the relationship between seagrass and Labyrinthula spp. diversity in coastal waters, we examined the diversity and microhabitat association of Labyrinthula spp. in 2 inlets on Florida's Atlantic Coast, the Indian River Lagoon (IRL) and Banana River. We used amplicon-based high throughput sequencing with 2 newly designed primers to amplify Labyrinthula spp. from 5 seagrass species, water, and sediments to determine their spatial distribution and microhabitat associations. The SSU primer set identified 12 Labyrinthula zero-radius operational taxonomic units (ZOTUs), corresponding to at least 8 putative species. The ITS1 primer set identified 2 ZOTUs, corresponding to at least 2 putative species. Based on our phylogenetic analyses, which include sequences from previous studies that assigned seagrass-related pathogenicity to Labyrinthula clades, all but one of the ZOTUs that we recovered with the SSU primers were from non-pathogenic species, while the 2 ZOTUs recovered with the ITS1 primers were from pathogenic species. Some of the ZOTUs were widespread across the sampling sites and microhabitats (e.g. SSU ZOTU_10), and most were present in more than one site. Our results demonstrate that targeted metabarcoding is a useful tool for examining the relationships between seagrass and Labyrinthula diversity in coastal waters.


Assuntos
Rios , Estramenópilas , Animais , Ecossistema , Florida , Filogenia
5.
Chemosphere ; 247: 125819, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31927184

RESUMO

Brown tides were first observed in 2009 in the north-western Bohai Sea (Qinhuangdao sea area), China, and blooms have occurred at different scales in late spring every year since then. Although the detrimental effects on marine organisms of the causative phytoplankton species Aureococcus anophagefferens have been extensively studied, the mechanism remains poorly understood. We used erythrocytes and adrenal gland chromaffin tumor cells (PC12) to explore the hemolytic activity and cytotoxicity, respectively, of chloroform and methanol extracts of cultured A. anophagefferens isolated from the north-western Bohai Sea area. The methanol extracts showed no hemolytic or cytotoxic activity. Chloroform extracts had a potent hemolytic effect on rabbit erythrocytes; thin layer chromatography (TLC) indicated that the hemolysin was a kind of glycolipid compound. Erythrocyte lysis assay showed that erythrocytes of sea bream were sensitive to the hemolysin, whereas those of human and chicken erythrocytes were insensitive. The hemolytic effects were elevated as temperatures rose from 4 °C to 37 °C. Hemolytic blocking experiments showed that sphingomyelin and d-xylose can inhibit hemolysis significantly, while osmotic protectants with different hydrated molecular diameters had no inhibition, and the hemolysins had no obvious phospholipase activity. The chloroform extracts of A. anophagefferens had significant inhibitory effects on the viability of PC12 cells, and can induce efflux of lactic dehydrogenase (LDH) of PC12 cells and lead to their necrosis.


Assuntos
Citotoxinas/isolamento & purificação , Hemólise/efeitos dos fármacos , Fitoplâncton/citologia , Animais , Células Cultivadas , China , Citotoxinas/farmacologia , Eritrócitos/efeitos dos fármacos , Proteínas Hemolisinas/química , Proteínas Hemolisinas/isolamento & purificação , Proteínas Hemolisinas/farmacologia , Humanos , Células PC12 , Fitoplâncton/patogenicidade , Coelhos , Ratos , Estações do Ano , Estramenópilas/citologia , Estramenópilas/patogenicidade , Temperatura
6.
Bioresour Technol ; 298: 122562, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31838241

RESUMO

Exergy analysis is powerful tool for process optimization and mechanism analysis. In this study, exergy analysis was performed for docosahexaenoic acid (DHA) fermentation process. More than 86% of input exergy was contributed by glucose. The exergy of biomass was about 64.66% of the total output exergy when the phosphate concentration was 4 g L-1. The exergy efficiencies of DHA (ηDHA) for the starting strains and the evolved strains under high oxygen concentration, low temperature, and two-factor conditions were also investigated. The ηDHA in the collected experimental data was not more than 20.9%. It was proved that there was a positive correlation between ηDHA and the biomass yield. It was indicated that adaptive laboratory evolution (ALE) improved biomass yield which had the most important effect on enhancing ηDHA and DHA yield (or DHA productivity). It is necessary to improve ηDHA through process optimization and ALE in future.


Assuntos
Ácidos Docosa-Hexaenoicos , Estramenópilas , Biomassa , Fermentação , Fosfatos
7.
J Environ Manage ; 253: 109680, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634748

RESUMO

Microalgae produce increased lipid content accompanied by a significant decrease in cell density with decreasing nitrate concentration. Magnetic fields (MF) have been reported as a factor that could accelerate metabolism and growth in microalgae culture. Thus, this study aimed to optimize the influence of MF and nitrate concentration (sodium nitrate, N) on the growth and lipid productivity of Nannochloropsis oculata. A single-factor experiment integrated with response surface methodology (RSM) via central composite design (CCD) was performed. The results showed that the maximum specific growth rate (0.24 d-1) and maximum lipid productivity (38 mg L-1 d-1) obtained in this study were higher than those of the control culture (by 166% and 103%, respectively). This study also found that the two-way interaction term MF × N had a significant effect on cell growth but not on lipid production. It was concluded that to design appropriate MF for enhanced lipid productivity due to cell growth, further research must focus on developing an understanding of the relationship between the bioeffects of the magnetic field and the proteomic changes involved in lipid accumulation strategies. This approach would enable the design of conditions to obtain inexpensive high-value products from N. oculata.


Assuntos
Microalgas , Estramenópilas , Biomassa , Lipídeos , Campos Magnéticos , Proteômica
8.
Chemosphere ; 245: 125669, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31881385

RESUMO

Coagulation and flocculation can remove particulate algal cells effectively; however, they are not very effective for removing dissolved algal organic matter (AOM) in drinking water plants. In this work, optimum coagulation conditions using alum for both extracellular and intracellular organic matter of six different algal and cyanobacterial species were determined. Different coagulation conditions such as alum dosage, pH, and initial dissolved organic carbon (DOC) were tested. Hydrophobicity, hydrophilicty, and transphilicity of the cellular materials were determined using resin fractionation method. The removal of DOC by coagulation correlated well with the hydrophobicity of the AOM. The disinfection by-product formation potential (DBPFP) of various fractions of AOM was determined after coagulation. Although, higher removal occurred for hydrophobic AOM during coagulation, specific DBPFP, which varied from 10 to 147 µg/mg-C was higher for hydrophobic AOM. Of all the six species, highest DBPFP occurred for Phaeodactylum tricornutum, an abundant marine diatom species, but is increasingly found in surface water.


Assuntos
Compostos de Alúmen , Cianobactérias/química , Desinfecção , Floculação , Estramenópilas/química , Poluentes Químicos da Água/análise , Diatomáceas/química , Interações Hidrofóbicas e Hidrofílicas , Solubilidade , Poluentes Químicos da Água/química , Purificação da Água
9.
J Sci Food Agric ; 100(2): 587-594, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31591720

RESUMO

BACKGROUND: The research deals with the addition of microalgae Schizochytrium limacinum as an alternative to fish oil in a feed-mixture for laying-hens and its effect on the deposition of n-3 polyunsaturated fatty acids (n-3-PUFAs) [α-linoleic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] in the lipids of egg yolks. In the study, 240 Tetra SL laying hens housed in enriched cages were used, divided into six groups, each in five repetitions. Groups E1, E3 and E5 were given 0.5%, 1.0% and 1.5% microalgae and groups E2, E4 and E6 were given feed mixtures with 0.5%, 1.0% and 1.5% fish oil. The mixtures were modified on the basis of 17% of the crude protein and 11.7 MJ ME kg-1 . RESULTS: The results showed satisfactory disposal of n-3 PUFA in egg yolks of laying-hens fed mixtures with the addition of either fish oil or microalgae. Eggs of E1, E3 and E5 groups contained in 100 g: 321.07 mg, 361.60 mg and 399.34 mg n-3 PUFA, respectively (P < 0.001). Eggs of E2, E4 and E6 groups contained in 100 g: 346.25 mg, 346.17 mg and 369.02 mg n-3 PUFA, respectively (P < 0.001). By increasing the content of fish oil or microalgae in feed-mixtures for laying hens, the ratio of n-6/n-3 PUFA in egg yolk lipids (P < 0.001) was decreased. CONCLUSION: Our results justified the usage of the microalgae Schizochytrium limacinum in the enrichment of table eggs with n-3 fatty acids as an alternative feed to fish oil. © 2019 Society of Chemical Industry.


Assuntos
Galinhas/metabolismo , Ovos/análise , Ácidos Graxos Ômega-3/análise , Óleos de Peixe/análise , Microalgas/metabolismo , Estramenópilas/metabolismo , Ração Animal/análise , Animais , Gema de Ovo/química , Gema de Ovo/metabolismo , Ácidos Graxos Ômega-3/metabolismo , Feminino , Óleos de Peixe/metabolismo , Microalgas/química , Estramenópilas/química
10.
PLoS One ; 14(12): e0226650, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31851717

RESUMO

The ability to identify drivers responsible for algal community shifts is an important aspect of environmental issues. The lack of long-term datasets, covering periods prior to these shifts, is often limiting our understanding of drivers responsible. The freshwater alga, Gonyostomum semen (Raphidophyceae), has significantly increased distribution and mass occurrences in Scandinavian lakes during the past few decades, often releasing a skin irritating slime that causes discomfort for swimmers. While the alga has been extensively studied, long-term data from individual lakes are often absent or greatly limited and drivers behind this species' success are still not clear. However, if specific and persistent taxa biomarkers for G. semen could be detected in dated sediment cores, long-term data would be improved and more useful. To test for biomarkers, we examined the pigment composition of several G. semen strains in culture. Further, dated sediment core samples from Lake Lundebyvann, Norway, were used to test the pigments' suitability as biomarkers in paleolimnological studies. Modifications to a common analysis allowed for the successful detection of the polar xanthophyll heteroxanthin and the non-polar chlorophyll a, as well as several other algal pigments by using high performance liquid chromatography-photometric diode arrays (HPLC-PDA). Heteroxanthin was confirmed by liquid chromatography-mass spectrometry (LC-MS) and detected by HPLC-PDA in all examined G. semen strains, along with chlorophyll a. Using HPLC-PDA, we also identified and confirmed the presence of the biomarker, xanthophyll heteroxanthin, in sediment core samples up to 60 years of age. The specificity of this xanthophyll was also tested by examining a wide range of algal strains from common Norwegian phytoplankton species. Heteroxanthin was not detected in any species commonly occurring in significant amounts in Norwegian lakes. We therefore conclude that heteroxanthin is a suitable pigment biomarker for G. semen and that this pigment can be successfully used for paleolimnological studies.


Assuntos
Biomarcadores/análise , Sêmen/química , Estramenópilas/química , Xantofilas/análise , Lagos , Noruega , Pigmentação
11.
Genes (Basel) ; 11(1)2019 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-31861932

RESUMO

Transposable elements (TEs), activated as a response to unfavorable conditions, have been proposed to contribute to the generation of genetic and phenotypic diversity in diatoms. Here we explore the transcriptome of three warm water strains of the diatom Leptocylindrus aporus, and the possible involvement of TEs in their response to changing temperature conditions. At low temperature (13 °C) several stress response proteins were overexpressed, confirming low temperature to be unfavorable for L. aporus, while TE-related transcripts of the LTR retrotransposon superfamily were the most enriched transcripts. Their expression levels, as well as most of the stress-related proteins, were found to vary significantly among strains, and even within the same strains analysed at different times. The lack of overexpression after many months of culturing suggests a possible role of physiological plasticity in response to growth under controlled laboratory conditions. While further investigation on the possible central role of TEs in the diatom stress response is warranted, the strain-specific responses and possible role of in-culture evolution draw attention to the interplay between the high intraspecific variability and the physiological plasticity of diatoms, which can both contribute to the adaptation of a species to a wide range of conditions in the marine environment.


Assuntos
Elementos de DNA Transponíveis , Perfilação da Expressão Gênica/métodos , Estramenópilas/genética , Adaptação Fisiológica , Resposta ao Choque Frio , Evolução Molecular , Regulação da Expressão Gênica , Análise de Sequência de RNA
12.
Harmful Algae ; 89: 101669, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31672237

RESUMO

Once limited to the Laguna Madre of Texas, blooms of the brown tide organism, Aureoumbra lagunensis, have recently been reported elsewhere. Previous studies have focused on the role of extreme hypersalinity and lack of grazing pressure as facilitators of brown tide blooms. However, development of blooms in systems that are not experiencing extreme hypersalinity, and also that are undergoing eutrophication, suggests that our understanding of A. lagunensis bloom dynamics requires additional refinement. The goal of this study was to quantify the spatial-temporal distribution of, and potential controls upon, A. lagunensis in Baffin Bay, Texas. Five sites were sampled monthly over a three-year period, encompassing nearly two years of drought and hypersaline conditions, followed by a high rainfall, lower salinity period. A. lagunensis abundances were higher during drought in May 2013 - March 2015 compared to the higher rainfall period of April 2015 - April 2016. Abundances typically peaked in summer months, though the seasonal pattern was disrupted in 2015 during the shift from high to low salinity conditions. Persistently high abundances of A. lagunensis were observed in the Laguna Salada tributary of Baffin Bay, which typically has higher dissolved organic nitrogen concentrations and may be less well flushed than other parts of Baffin Bay. Thus this location may serve as a reservoir for A. lagunensis in the system. Overall, A. lagunensis abundance was positively correlated with DOC and salinity, and negatively correlated with ammonium, orthophosphate, and ciliate biovolume. These results suggest a variety of physical, chemical and biological factors affect A. lagunensis population dynamics and stress the need for more research on nutrient-A. lagunensis relationships.


Assuntos
Baías , Estramenópilas , Eutrofização , Salinidade , Texas
13.
Protist ; 170(5): 125682, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31568885

RESUMO

Stramenopiles are one of the major eukaryotic assemblages. This group comprises a wide range of species including photosynthetic unicellular and multicellular algae, fungus-like osmotrophic organisms and many free-living phagotrophic flagellates. However, the phylogeny of the Stramenopiles, especially relationships among deep-branching heterotrophs, has not yet been resolved because of a lack of adequate transcriptomic data for representative lineages. In this study, we performed multigene phylogenetic analyses of deep-branching Stramenopiles with improved taxon sampling. We sequenced transcriptomes of three deep-branching Stramenopiles: Incisomonas marina, Pseudophyllomitus vesiculosus and Platysulcus tardus. Phylogenetic analyses using 120 protein-coding genes and 56 taxa indicated that Pl. tardus is sister to all other Stramenopiles while Ps. vesiculosus is sister to MAST-4 and form a robust clade with the Labyrinthulea. The resolved phylogenetic relationships of deep-branching Stramenopiles provide insights into the ancestral traits of the Stramenopiles.


Assuntos
Filogenia , Estramenópilas/classificação , Estramenópilas/genética , Transcriptoma
14.
Eur J Protistol ; 71: 125639, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31550629

RESUMO

Opalinids are a large group of anaerobic protists, mainly inhabiting the cloacae of amphibians (frogs and toads). The classification of this group has not been fully resolved, because of a lack of molecular information. Here, we give a redescription of Opalina triangulata Metcalf, 1923, collected from the rectum of the frog Fejervarya limnocharis, based on detailed morphological and molecular data. Our phylogenetic analyses confirmed the monophyly of Opalinata. Within it, Opalinea were monophyletic with O. triangulata and O. undulata as well as two Protoopalina species grouping together. Karotomorpha and Proteromonas did not group together confirming the paraphyly of Proteromonadea. Meanwhile, the ITS2 secondary structural similarities as well as G-C content revealed greater similitudes between Opalina species and P. lacertae than with Blastocystis hominis, which is in accordance with their position as sister clades in the SSU rDNA-based phylogenies.


Assuntos
Anuros/parasitologia , Filogenia , Estramenópilas/classificação , Animais , DNA Ribossômico/genética , Estramenópilas/citologia , Estramenópilas/genética
15.
Fish Shellfish Immunol ; 94: 880-888, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31562894

RESUMO

The humpback grouper (Cromileptes altivelis) is a commercially valuable species of the family Epinephelidae; however, its marketization suffers from slow growth speed, low survival rate, and various pathogenic diseases. Lactococcus lactis and Schizochytrium limacinum are commonly used as immunostimulants due to their health benefits for the aquatic organisms. In the present study, we assessed the effects of dietary supplementation with L. lactis HNL12 combined with S. limacinum algal meal on the growth performances, innate immune response, and disease resistance of C. altivelis against Vibrio harveyi. The results showed that fish fed with a combination diet of L. lactis and S. limacinum exhibited significantly higher final weight, percent weight gain, and specific growth rate compared with groups fed with them alone. A bacterial challenge experiment indicated that the group fed with the L. lactis combined with S. limacinum diet achieved the highest relative percent of survival value (68.63%), suggesting that L. lactis and S. limacinum significantly improved the disease resistance against V. harveyi after a 4-week feeding trial. Moreover, the respiratory burst activity of macrophages of fish fed with a L. lactis combined with S. limacinum diet was significantly higher than that of fish fed the control diet after 1, 2, and 3 weeks of feeding. The serum superoxide dismutase of fish fed with a L. lactis combined with S. limacinum diet significantly increased compared to those fed the control diet after 1 and 2 weeks of feeding, while the serum alkaline phosphatase of fish fed with a L. lactis combined with S. limacinum diet after 2 and 4 weeks was significantly increased, compared to the control group. The serum lysozyme activities of fish fed with a L. lactis combined with S. limacinum diet significantly increased compared to the control group after 2 weeks of feeding. Furthermore, transcriptome sequencing of the C. altivelis head kidney was conducted to explore the immune-regulating effects of the L. lactis combined with S. limacinum diet on C. altivelis. A total of 86,919 unigenes, annotated by at least one of the reference databases (Nr, Swiss-Prot, GO, COG, and KEGG), were assembly yielded by de novo transcriptome. In addition, 157 putative differentially expressed genes (DEGs) were identified between the L. lactis combined with S. limacinum group and the control group. For pathway enrichment, the DEGs were categorized into nine KEGG pathways, which were mainly related to infective diseases, antigen processing and presentation, digestive system, and other immune system responses. The findings of this study suggest that the L. lactis combined with S. limacinum diet can induce positive effects on the growth, immunity, and disease resistance of C. altivelis against V. harveyi. This study expands our understanding of the synergistic combinations of probiotics and prebiotics in aquaculture.


Assuntos
Bass/imunologia , Doenças dos Peixes/imunologia , Imunidade Inata/efeitos dos fármacos , Lactococcus lactis/química , Prebióticos , Probióticos/farmacologia , Estramenópilas/química , Adjuvantes Imunológicos/farmacologia , Animais , Bass/crescimento & desenvolvimento , Resistência à Doença/efeitos dos fármacos , Resistência à Doença/imunologia , Vibrio/fisiologia , Vibrioses/imunologia , Vibrioses/veterinária
16.
J Dairy Sci ; 102(12): 10934-10946, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31563312

RESUMO

Modification of milk and cheese fat to contain long-chain n-3 fatty acids (FA) by feeding microalgae (ALG) to dairy cows has the potential to improve human health, but the subsequent effect on the sensory attributes of dairy products is unclear. The objective was to determine the effect of feeding dairy cows different amounts of ALG that was rich in docosahexaenoic acid (DHA) on milk and cheese FA profile, cheese sensory attributes, and cow performance. Twenty Holstein dairy cows were randomly allocated to 1 of 4 dietary treatments in a 4 × 4 row and column design, with 4 periods of 28 d, with cheddar cheese production and animal performance measurements undertaken during the final 7 d of each period. Cows were fed a basal diet that was supplemented with ALG (Schizochytrium limancinum) at 4 rates: 0 (control, C), 50 (LA), 100 (MA), or 150 g (HA) of ALG per cow per day. We found that both milk and cheese fat content of DHA increased linearly with ALG feed rate and was 0.29 g/100 g FA higher in milk and cheese from cows fed HA compared with C. Supplementation with ALG linearly reduced the content of saturated FA and the ratio of n-6:n-3 FA in milk and cheese. Supplementation with ALG altered 20 out of the 32 sensory attributes, with a linear increase in cheese air holes, nutty flavor, and dry mouth aftertaste with ALG inclusion. Creaminess of cheese decreased with ALG inclusion rate and was positively correlated with saturated FA content. We also observed a quadratic effect on fruity odor, which was highest in cheese from cows fed HA and lowest in LA, and firmness and crumbliness texture, being highest in MA and lowest in HA. Supplementation with ALG had no effect on the dry matter intake, milk yield, or live weight change of the cows, with mean values of 23.1, 38.5, and 0.34 kg/d respectively, but milk fat content decreased linearly, and energy-corrected milk yield tended to decrease linearly with rate of ALG inclusion (mean values of 39.6, 38.4, 37.1, and 35.9 g/kg, and 41.3, 41.3, 40.5, and 39.4 kg/d for C, LA, MA, and HA, respectively). We conclude that feeding ALG to high-yielding dairy cows improved milk and cheese content of DHA and altered cheese taste but not cow performance, although milk fat content reduced as inclusion rate increased.


Assuntos
Ração Animal , Bovinos , Queijo , Ácidos Graxos/análise , Microalgas , Leite/química , Ração Animal/análise , Animais , Indústria de Laticínios , Dieta/veterinária , Suplementos Nutricionais , Ácidos Docosa-Hexaenoicos/análise , Ácidos Graxos Ômega-3/análise , Feminino , Qualidade dos Alimentos , Lactação , Microalgas/química , Estramenópilas
17.
J Agric Food Chem ; 67(34): 9683-9693, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31379160

RESUMO

Schizochytrium sp. A-2 is a heterotrophic marine fungus used for the commercial production of docosahexaenoic acid (DHA). However, the pattern of the distribution of DHA and how DHA is channeled into phospholipid (PL) and triacylglycerol (TAG) are unknown. In this study, we systematically analyzed the distribution of DHA in TAG and PL during the growth of the cell. The migration of DHA from PL to TAG was presumed during the fermentation cycle. DHA and docosapentaenoic acid were accumulated in both TAG and phosphatidylcholine (PC), whereas eicosapentaenoic acid was mainly deposited in PC. RNA seq revealed that malic enzyme may provide lipogenic NADPH. In addition, long-chain acyl-CoA synthase and acyl-CoA:lysophosphatidylcholine acyltransferase may participate in the accumulation of DHA in PL. No phosphatidylcholine:diacylglycerol cholinephosphotransferase was identified from the genome sequence. In contrast, phospholipid:diacylglycerol acyltransferase-mediated acyl-CoA-independent TAG synthesis pathway and phospholipase C may contribute to the channeling of DHA from PC to TAG.


Assuntos
Ácidos Docosa-Hexaenoicos/metabolismo , Estramenópilas/genética , Estramenópilas/metabolismo , Transcriptoma , 1-Acilglicerofosfocolina O-Aciltransferase/genética , 1-Acilglicerofosfocolina O-Aciltransferase/metabolismo , Acil Coenzima A/genética , Acil Coenzima A/metabolismo , Transporte Biológico , Fosfolipídeos/metabolismo , Estramenópilas/química , Triglicerídeos/metabolismo , Fosfolipases Tipo C/genética , Fosfolipases Tipo C/metabolismo
18.
J Dairy Sci ; 102(10): 8862-8873, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421880

RESUMO

The aim of this study was to determine the effect of docosahexaenoic acid-rich algae (DHA-RA) supplementation in milk replacer (MR) on performance, selected cytokine expression in lymphocytes, and blood immunoglobulin concentration in newborn dairy calves. Forty female Holstein-Friesian calves (8.6 ± 0.8 d old and 41.1 ± 4.3 kg; mean ± standard deviation) were blocked by date of birth and allocated into 4 experimental groups (10 animals/group): (1) not supplemented with DHA-RA, (2) supplemented with 9 g of DHA-RA/d in MR, (3) supplemented with 18 g of DHA-RA/d in MR, and (4) supplemented with 27 g of DHA-RA/d in MR. Milk replacer was fed in an amount equal to 900 g of MR powder/d (as fed), 2 times a d, for 49 d. Starter mixture (SM) was fed ad libitum beginning on d 15 of the study. Each calf was in the study over a period of 49 d. The MR and SM intake and fecal score were recorded daily and body weight was recorded weekly. Blood samples were collected before the morning feeding, at the beginning of the study, every consecutive week, and at the end of the study for morphology and smear analysis, serum immunoglobulin level (IgG, IgA, and IgM), and lymphocyte isolation. The mRNA isolated from lymphocytes was checked for TNFα, IL-1ß, IL-6, and p65 expression. Average daily gain between d 1 to 14 of the study increased quadratically with increasing dose of DHA-RA. However, average daily gain between d 15 to 49 of the study tended to linearly decrease and over the whole study linearly decreased with increasing dose of DHA-RA. The MR intake decreased linearly between d 1 to 14 of the study and over the whole study, and mean SM intake decreased quadratically with increasing dose of DHA-RA. Feed efficiency increased quadratically and fecal score decreased quadratically during the first 14 d of the study. Increasing dose of DHA-RA led to cubic changes in feed efficiency and fecal score between d 15 and 49 of the study. Overall, over the whole study period a tendency was observed for lower fecal score for the DHA-RA supplemented groups. Interleukin-1ß mRNA expression decreased linearly, whereas the mRNA expression of p65 and TNFα as well as serum IgG concentration tended to decrease linearly with increasing dose of supplemental DHA-RA. No effect of group was found on IgA and IgM serum level and the majority of blood parameters. Altogether, treatment worsened production variables but seemed to have a beneficial effect on the immune system of calves.


Assuntos
Ração Animal , Bovinos , Suplementos Nutricionais , Ácidos Docosa-Hexaenoicos/farmacologia , Substitutos do Leite/farmacologia , Estramenópilas , Ração Animal/análise , Animais , Animais Recém-Nascidos , Peso Corporal , Dieta/veterinária , Feminino , Sistema Imunitário/efeitos dos fármacos , Linfócitos/efeitos dos fármacos , Linfócitos/metabolismo , Leite , Substitutos do Leite/química , Desmame
19.
Mar Drugs ; 17(8)2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31370264

RESUMO

The following study reports on the first thraustochytrid isolates identified from Iceland. They were collected from three different locations off the northern coast of the country (Location A, Skagaströnd; Location B, Hveravík; and Location C, Eyjafjörður). Using 18S rDNA sequence analysis, isolates from Locations A and B were identified within the Thraustochytrium kinnei species while other isolates within the Sicyoidochytrium minutum species when compared to other known strains. Cells isolated from Locations A ( 2 . 10 ± 0 . 70 g/L) and B ( 1 . 54 ± 0 . 17 g/L) produced more biomass than the ones isolated from Location C ( 0 . 43 ± 0 . 02 g/L). This study offers the first-time examination of the utility of byproducts from fisheries as a nitrogen source in media formulation for thraustochytrids. Experiments showed that isolates produced more biomass (per unit of substrate) when cultured on nitrogen of marine ( 2 . 55 ± 0 . 74 g/L) as compared to of commercial origin (  1 . 06 ± 0 . 57 g/L). Glycerol ( 2 . 43 ± 0 . 56 g/L) was a better carbon source than glucose ( 1 . 84 ± 0 . 57 g/L) in growth studies. Fatty acid (FA) profiles showed that the isolates from Location C (S. minutum) had low ratios of monounsaturated ( 4 . 21 ± 2 . 96 % ) and omega-6 ( 0 . 68 ± 0 . 59 % ) FAs. However, the isolates also had high ratios of docosahexaenoic acid (DHA; 35 . 65 ± 1 . 73 % ) and total omega-3 FAs ( 40 . 39 ± 2 . 39 % ), indicating that they could serve as a source of marine oils for human consumption and in aquaculture feeds. The T. kinnei isolates from Location A could be used in biodiesel production due to their high ratios of monounsaturated ( 18 . 38 ± 6 . 27 % ) long chain ( 57 . 43 ± 8 . 27 % ) FAs.


Assuntos
Organismos Aquáticos/metabolismo , Biocombustíveis , Microbiologia Industrial/métodos , Estramenópilas/metabolismo , Organismos Aquáticos/isolamento & purificação , Técnicas de Cultura de Células/métodos , Meios de Cultura/química , Ácidos Graxos Ômega-3/isolamento & purificação , Ácidos Graxos Ômega-3/metabolismo , Ácidos Graxos Ômega-6/isolamento & purificação , Ácidos Graxos Ômega-6/metabolismo , Pesqueiros , Glicerol/química , Islândia , Nitrogênio/química , Estramenópilas/isolamento & purificação
20.
World J Microbiol Biotechnol ; 35(8): 119, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332541

RESUMO

The microalgal genus of Nannochloropsis is considered one of the most promising organisms for the production of biofuels due to their high lipid content. Transformation systems for marine Nannochloropsis species have been established in the recent decade, however, genetic manipulation of Nannochloropsis limnetica, the only known freshwater species in this genus, is not yet available. Based on established marine Nannochloropsis species electrotransformation protocol, nuclear genetic transformation was established in N. limnetica, meanwhile the appropriate antibiotic selection concentration and electric field strength of electroporation were determined. For the selection of transformants in N. limnetica on plates, 0.07 µg mL-1 of zeocin or 5 µg mL-1 of hygromycin B was proved sufficient, and the transformation efficiency was < 2 × 10-8 with a single pulse ranging from 2200 to 2600 V using 2-mm electroporation cuvettes. Pretreatment of N. limnetica with 10 mM lithium acetate and 3 mM dithiothreitol before electroporation increased transformation efficiency hundreds of times, and the highest transformation efficiency of 10-11 × 10-6 was obtained with an electric field strength of 12,000 V/cm. Our results help to expand the biotechnological applications of this freshwater species and provide means for successful electrotransformation of other microalgae as well. High-efficiency transformation of freshwater Nannochloropsis pretreatment of N. limnetica with 10 mM lithium acetate and 3 mM dithiothreitol before electroporation increased transformation efficiency hundreds of times.


Assuntos
Eletroporação , Água Doce/microbiologia , Microalgas/metabolismo , Estramenópilas/metabolismo , Acetatos , Regulação da Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Microalgas/genética , Plasmídeos/genética , Plasmídeos/metabolismo , Estramenópilas/genética , Transformação Genética
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