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1.
Plant Mol Biol ; 104(4-5): 411-427, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32813231

RESUMO

KEY MESSAGE: A sugarcane MYB present in the culm induces suberin biosynthesis and is involved both with fatty acid and phenolics metabolism. Few transcription factors have been described as regulators of cell wall polymers deposition in C4 grasses. Particularly, regulation of suberin biosynthesis in this group of plants remains poorly understood. Here, we showed that the sugarcane MYB transcription factor ShMYB78 is an activator of suberin biosynthesis and deposition. ShMYB78 was identified upon screening genes whose expression was upregulated in sugarcane internodes undergoing suberization during culm development or triggered by wounding. Agrobacterium-mediated transient expression of ShMYB78 in Nicotiana benthamiana leaves induced the ectopic deposition of suberin and its aliphatic and aromatic monomers. Further, the expression of suberin-related genes was induced by ShMYB78 heterologous expression in Nicotiana benthamiana leaves. ShMYB78 was shown to be a nuclear protein based on its presence in sugarcane internode nuclear protein extracts, and protoplast transactivation assays demonstrated that ShMYB78 activates the promoters of the sugarcane suberin biosynthetic genes ß-ketoacyl-CoA synthase (ShKCS20) and caffeic acid-O-methyltransferase (ShCOMT). Our results suggest that ShMYB78 may be involved in the transcriptional regulation of suberin deposition, from fatty acid metabolism to phenylpropanoid biosynthesis, in sugarcane internodes.


Assuntos
Lipídeos/biossíntese , Proteínas de Plantas/genética , Saccharum/genética , Tabaco/metabolismo , Fatores de Transcrição/genética , Núcleo Celular , Regulação da Expressão Gênica de Plantas , Lipídeos/genética , Filogenia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Tabaco/genética , Fatores de Transcrição/metabolismo
2.
Protist ; 171(3): 125738, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32544845

RESUMO

This paper represents a comprehensive study of two new thraustochytrids and a marine Rhodotorula red yeast isolated from Australian coastal waters for their abilities to be a potential renewable feedstock for the nutraceutical, food, fishery and bioenergy industries. Mixotrophic growth of these species was assessed in the presence of different carbon sources: glycerol, glucose, fructose, galactose, xylose, and sucrose, starch, cellulose, malt extract, and potato peels. Up to 14g DW/L (4.6gDW/L-day and 2.8gDW/L-day) of biomass were produced by Aurantiochytrium and Thraustochytrium species, respectively. Thraustochytrids biomass contained up to 33% DW of lipids, rich in omega-3 polyunsaturated docosahexaenoic acid (C22:6, 124mg/g DW); up to 10.2mg/gDW of squalene and up to 61µg/gDW of total carotenoids, composed of astaxanthin, canthaxanthin, echinenone, and ß-carotene. Along with the accumulation of these added-value chemicals in biomass, thraustochytrid representatives showed the ability to secrete extracellular polysaccharide matrixes containing lipids and proteins. Rhodotorula sp lipids (26% DW) were enriched in palmitic acid (C16:0, 18mg/gDW) and oleic acid (C18:1, 41mg/gDW). Carotenoids (87µg/gDW) were mainly represented by ß-carotene (up to 54µg/gDW). Efficient growth on organic and inorganic sources of carbon and nitrogen from natural and anthropogenic wastewater pollutants along with intracellular and extracellular production of valuable nutrients makes the production of valuable chemicals from isolated species economical and sustainable.


Assuntos
Biodegradação Ambiental , Quitridiomicetos , Lipídeos/biossíntese , Rhodotorula , Poluentes da Água/metabolismo , Aciltransferases/metabolismo , Biomassa , Carotenoides/metabolismo , Quitridiomicetos/crescimento & desenvolvimento , Quitridiomicetos/isolamento & purificação , Quitridiomicetos/metabolismo , Ácidos Docosa-Hexaenoicos/biossíntese , Ácidos Graxos Insaturados/biossíntese , Nutrientes/metabolismo , Polissacarídeos/biossíntese , Rhodotorula/crescimento & desenvolvimento , Rhodotorula/isolamento & purificação , Rhodotorula/metabolismo , Água do Mar/microbiologia , Águas Residuárias/microbiologia , Áreas Alagadas
3.
PLoS One ; 15(6): e0234870, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32569317

RESUMO

Mucoromycota fungi possess a versatile metabolism and can utilize various substrates for production of industrially important products, such as lipids, chitin/chitosan, polyphosphates, pigments, alcohols and organic acids. However, as far as commercialisation is concerned, establishing industrial biotechnological processes based on Mucoromycota fungi is still challenging due to the high production costs compared to the final product value. Therefore, the development of co-production concept is highly desired since more than one valuable product could be produced at the time and the process has a potentially higher viability. To develop such biotechnological strategy, we applied a high throughput approach consisting of micro-titre cultivation and FTIR spectroscopy. This approach allows single-step biochemical fingerprinting of either fungal biomass or growth media without tedious extraction of metabolites. The influence of two types of nitrogen sources and different levels of inorganic phosphorus on the co-production of lipids, chitin/chitosan and polyphosphates for nine different oleaginous Mucoromycota fungi was evaluated. FTIR analysis of biochemical composition of Mucoromycota fungi and biomass yield showed that variation in inorganic phosphorus had higher effect when inorganic nitrogen source-ammonium sulphate-was used. It was observed that: (1) Umbelopsis vinacea reached almost double biomass yield compared to other strains when yeast extract was used as nitrogen source while phosphorus limitation had little effect on the biomass yield; (2) Mucor circinelloides, Rhizopus stolonifer, Amylomyces rouxii, Absidia glauca and Lichtheimia corymbifera overproduced chitin/chitosan under the low pH caused by the limitation of inorganic phosphorus; (3) Mucor circinelloides, Amylomyces rouxii, Rhizopus stolonifer and Absidia glauca were able to store polyphosphates in addition to lipids when high concentration of inorganic phosphorus was used; (4) the biomass and lipid yield of high-value lipid producers Mortierella alpina and Mortierella hyalina were significantly increased when high concentrations of inorganic phosphorus were combined with ammonium sulphate, while the same amount of inorganic phosphorus combined with yeast extract showed negative impact on the growth and lipid accumulation. FTIR spectroscopy revealed the co-production potential of several oleaginous Mucoromycota fungi forming lipids, chitin/chitosan and polyphosphates in a single cultivation process.


Assuntos
Biotecnologia/métodos , Técnicas de Cultura de Células/métodos , Quitina/biossíntese , Fungos , Lipídeos/biossíntese , Polifosfatos/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Meios de Cultura , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo
4.
J Oleo Sci ; 69(4): 359-368, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32249263

RESUMO

Biodiesel production from microalgae is still not commercially realized due to the high cost of production. High light-tolerance has been suggested as a desirable phenotype for efficient cultivation in large scale production systems under fluctuating outdoor conditions. Nevertheless, it has not been shown if algae with such a phenotype would have better efficiency for lipid production. To determine lipid productivity in high light-tolerant mutants, and to understand the pathways involved in high light-tolerant phenotype, two very high light-tolerant mutants of the green alga Chlamydomonas reinhardtii - CAL028_01_28 and CAL034_01_48 - were selected from eighteen high light-tolerant mutants from the CAL collection. Under high light intensity conditions, and the presence of reactive oxygen species, which are conditions constantly experienced by algae growing in open-pond environments, these strains exhibited higher photosynthetic efficiency and improved survival. The physiological characterization of these mutants revealed that the detoxification of ROS by carotenoids and antioxidant enzymes is crucial for their growth under high light conditions. Neither mutant was affected in terms of its ability to accumulate lipid under nitrogen-depleted condition. More importantly, lipid productivity under high light conditions increased twofold in these mutants compared to that of the wild-type. Taken together, very high light-tolerant mutants confer a high potential for biofuel production under outdoor conditions, and their improved ability to survive under oxidative stress is an important key for efficient growth under outdoor conditions.


Assuntos
Adaptação Ocular/genética , Chlamydomonas/genética , Chlamydomonas/metabolismo , Lipídeos/biossíntese , Mutação , Fotofobia/genética , Biocombustíveis , Chlamydomonas/fisiologia , Estresse Oxidativo , Fenótipo , Espécies Reativas de Oxigênio/metabolismo
5.
Yeast ; 37(5-6): 348-355, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32212181

RESUMO

Candida hispaniensis is an oleaginous yeast with a great potential for production of single cell oil according to its naturally high lipid accumulation capacity. Its unusual small genome size trait is also attractive for fundamental research on genome evolution. Our physiological study suggests a great potential for lipid production, reaching 224 mg/g of cell dry weight in glucose minimum medium. C. hispaniensis is also able to secrete up to 34.6 mg/L of riboflavin promising further riboflavin production improvements by cultivation optimization and genetic engineering. However, while its genome sequence has been released very recently, no genetic tools have been described up to now for this yeast limiting its use for fundamental research and for exploitation in an industrial biotechnology. We report here the first genetic modification of C. hispaniensis by introducing a heterologous invertase allowing the growth on sucrose using a biolistic transformation approach using a dedicated vector. The first genetic tool and transformation method developed here appear as a proof of concept, and while it would benefit from further optimization, heterogeneous expression of invertase allows for metabolism of an additional sugar and shows heterologous enzyme production capacity.


Assuntos
Candida/genética , Candida/metabolismo , Produto da Acumulação Lipídica , Lipídeos/biossíntese , Biotecnologia , Candida/citologia , Candida/enzimologia , Glucose/metabolismo , Metabolismo dos Lipídeos , Riboflavina/biossíntese , Transformação Genética , Yarrowia/genética , beta-Frutofuranosidase
6.
Electron. j. biotechnol ; 44: 60-68, Mar. 2020. tab, graf, ilus
Artigo em Inglês | LILACS | ID: biblio-1087705

RESUMO

Background: Oleaginous yeasts can be grown on different carbon sources, including lignocellulosic hydrolysate containing a mixture of glucose and xylose. However, not all yeast strains can utilize both the sugars for lipogenesis. Therefore, in this study, efforts were made to isolate dual sugar-utilizing oleaginous yeasts from different sources. Results: A total of eleven isolates were obtained, which were screened for their ability to utilize various carbohydrates for lipogenesis. One promising yeast isolate Trichosporon mycotoxinivorans S2 was selected based on its capability to use a mixture of glucose and xylose and produce 44.86 ± 4.03% lipids, as well as its tolerance to fermentation inhibitors. In order to identify an inexpensive source of sugars, nondetoxified paddy straw hydrolysate (saccharified with cellulase), supplemented with 0.05% yeast extract, 0.18% peptone, and 0.04% MgSO4 was used for growth of the yeast, resulting in a yield of 5.17 g L−1 lipids with conversion productivity of 0.06 g L−1 h−1 . Optimization of the levels of yeast extract, peptone, and MgSO4 for maximizing lipid production using Box­Behnken design led to an increase in lipid yield by 41.59%. FAME analysis of single cell oil revealed oleic acid (30.84%), palmitic acid (18.28%), and stearic acid (17.64%) as the major fatty acids. Conclusion: The fatty acid profile illustrates the potential of T. mycotoxinivorans S2 to produce single cell oil as a feedstock for biodiesel. Therefore, the present study also indicated the potential of selected yeast to develop a zero-waste process for the complete valorization of paddy straw hydrolysate without detoxification


Assuntos
Trichosporon/metabolismo , Oryza , Xilose/isolamento & purificação , Trichosporon/química , Óleos/química , Lipogênese , Biocombustíveis , Fermentação , Glucose/isolamento & purificação , Hidrólise , Lignina/metabolismo , Lipídeos/biossíntese
7.
Appl Microbiol Biotechnol ; 104(6): 2731-2743, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32002603

RESUMO

There are a large number of valuable substances in diatoms, such as neutral lipid and pigments. However, due to the lack of clear metabolic pathways, their applications are still limited. Recently, chemical modulators are found to be powerful tools to investigate the metabolic pathways of neutral lipids. Thus, in this study, to identify new neutral lipid accumulation effectors, we screened the natural products that we separated before in the model diatom Phaeodactylum tricornutum (P. tricornutum) by using Nile-red staining method. Two compounds, penicillide and verrucarin J which were isolated from two marine fungal strains, were identified to promote neutral lipid accumulation. However, penicillide and verrucarin J were also found to significantly inhibit the growth of P. tricornutum through specifically inhibiting the photosynthesis of P. tricornutum. Quantitative analysis results showed that penicillide and verrucarin J significantly increased total lipid and triacylglycerol (TAG) contents, which are consistent with previous Nile-red staining results. The expression of key genes such as DGAT2D, GPAT2, LPAT2, and PAP involved in TAG synthesis and unsaturated fatty acids also increased after penicillide and verrucarin J treatments. Besides, many TAG-rich plastoglobuli formed in plastids shown by increased lipid droplets in the cytosol. Finally, penicillide and verrucarin J were found to reduce the expression of synthetic genes of fucoxanthin, and consequently reduced the content of fucoxanthin, indicating that there might be crosstalk between lipid metabolism and fucoxanthin metabolism. Thus, our work exhibits two useful compounds that could be used to further study the metabolic pathways of neutral lipid and fucoxanthin, which will fulfill the promise of diatoms as low cost, high value, sustainable feedstock for high-value products such as neutral lipid and pigments.


Assuntos
Produtos Biológicos/farmacologia , Diatomáceas/efeitos dos fármacos , Fungos/química , Metabolismo dos Lipídeos/efeitos dos fármacos , Redes e Vias Metabólicas/efeitos dos fármacos , Organismos Aquáticos/química , Produtos Biológicos/química , Lipídeos/biossíntese , Coloração e Rotulagem , Tricotecenos/química , Tricotecenos/farmacologia
8.
Sci Rep ; 10(1): 1530, 2020 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-32001724

RESUMO

Microalgae cultivation on tannery wastewater (TWW) has been examined in some studies as a possible biological application to reduce contamination load and discharge effluents safely. However, Growth aspects, different tolerate strains and enriching the medium were not well investigated. In our study we applied Scenedesmus sp., Chlorella variabilis and Chlorella sorokiniana with different TWW concentrations. C. sorokiniana and C. variabilis cell density, chlorophyll, and sugar content grew substantially as compared to control. C. sorokiniana biomass and total lipids folded three and two times in 25% and 40% TWW, respectively as compared to control. Scenedesmus sp. showed longer lag phase and lower performance compared to the other two strains. Kelp waste extract (KWE) was added to balance the nutrients supply for C. sorokiniana, of which growth and effluents indicators were then greatly promoted in all concentrations. As the lag phase was shortened from 8 to 4 days in 60% concentration, subsequently, chlorophyll, carbohydrates, biomass and total lipids appreciated by 184%, 400%, 162% and 135%, respectively. Furthermore, the COD and ammonium removals improved by 51% and 45%, respectively. These outcomes emphasize the suitability of using TWW for microalgae cultivation with the suitable concentration while adding kelp waste extract for further enhancement.


Assuntos
Biocombustíveis/microbiologia , Águas Residuárias/microbiologia , Biomassa , Chlorella/crescimento & desenvolvimento , Lipídeos/biossíntese , Microalgas/crescimento & desenvolvimento , Scenedesmus/crescimento & desenvolvimento , Águas Residuárias/análise
9.
Appl Microbiol Biotechnol ; 104(7): 3133-3144, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32076780

RESUMO

Six local isolates of yeasts were screened for cell mass and lipid production in mixed glucose and xylose medium. Candida tropicalis SY005 and Trichosporon (Apiotrichum) loubieri SY006 showed significant lipid accumulation of 24.6% and 32% (dry cell weight), respectively when grown in medium containing equal mass of both the sugars. SY005 produced relatively higher cell mass of 9.66 gL-1 due to higher rate of sugar consumption, which raised the lipid productivity of the organism to 0.792 gL-1day-1 as compared to 0.446 gL-1day-1 in SY006. When grown with each sugar separately, the xylose consumption rate of SY005 was found to be 0.55 gL-1 h-1 after 4 days as compared to 0.52 gL-1 h-1 for SY006. Transcript expression of the high affinity xylose transporter (Cthaxt), xylose reductase (Ctxyl1), and xylitol dehydrogenase (Ctxyl2) of SY005 was monitored to unravel such high rate of sugar consumption. Expression of all the three genes was observed to vary in mixed sugars with Cthaxt exhibiting the highest expression in presence of only xylose. Expression levels of both Ctxyl1 and Ctxyl2, involved in xylose catabolism, were maximum during 24-48 h of growth, indicating that xylose utilization started in the presence of glucose, which was depleted in the medium after 96 h. Together, the present study documents that C. tropicalis SY005 consumes xylose concomitant to glucose during early period of growth, and it is a promising yeast strain for viable production of storage lipid or other high-value oleochemicals utilizing lignocellulose hydrolysate.


Assuntos
Candida tropicalis/metabolismo , Lipídeos/biossíntese , Xilose/metabolismo , Candida tropicalis/genética , Candida tropicalis/crescimento & desenvolvimento , Meios de Cultura/química , Fermentação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Glucose/análise , Glucose/metabolismo , Especificidade da Espécie , Trichosporon/genética , Trichosporon/crescimento & desenvolvimento , Trichosporon/metabolismo , Xilose/análise , Leveduras/classificação , Leveduras/genética , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo
10.
Artigo em Inglês | MEDLINE | ID: mdl-32065919

RESUMO

The mechanisms regulating, and modulating potato wound-healing processes are of great importance in reducing tuber infections, reducing shrinkage and maintaining quality and nutritional value for growers and consumers. Wound-induced changes in tuber polyamine metabolism have been linked to the modulation of wound healing (WH) and in possibly providing the crucial amount of H2O2 required for suberization processes. In this investigation we determined the effect of inhibition of specific steps within the pathway of polyamine metabolism on polyamine content and the initial accumulation of suberin polyphenolics (SPP) during WH. The accumulation of SPP represents a critical part of the beginning or inchoate phase of tuber WH during closing-layer formation because it serves as a barrier to bacterial infection and is a requisite for the accumulation of suberin polyaliphatics which provide the barrier to fungal infection. Results showed that the inhibitor treatments that caused changes in polyamine content generally did not influence wound-induced accumulation of SPP. Such lack of correlation was found for inhibitors involved in metabolism and oxidation of putrescine (arginine decarboxylase, ornithine decarboxylase, and diamine oxidase). However, accumulation of SPP was dramatically reduced by treatment with guazatine, a potent inhibitor of polyamine oxidase (PAO), and methylglyoxal-bis(guanylhydrazone), a putative inhibitor of S-adenosylmethione decarboxylase which may also cross-react to inhibit PAO. The mode of action of these inhibitors is presumed to be blockage of essential H2O2 production within the WH cell wall. These results are of great importance in understanding the mechanisms modulating WH and ultimately controlling related infections and associated postharvest losses.


Assuntos
Diaminas/antagonistas & inibidores , Lipídeos/biossíntese , Proteínas de Plantas/metabolismo , Tubérculos/metabolismo , Poliaminas/antagonistas & inibidores , Solanum tuberosum/metabolismo , Carboxiliases/metabolismo , Diaminas/metabolismo , Guanidinas/metabolismo , Mitoguazona/metabolismo , Oxirredução , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Poliaminas/metabolismo , Putrescina/metabolismo , Solanum tuberosum/enzimologia
11.
J Biotechnol ; 310: 21-31, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32004579

RESUMO

Some Rhodotorula spp. have been characterized as oleaginous yeasts. Under certain culture conditions they can accumulate neutral lipids, which are mainly triglycerides (TAG). Microbial TAG that can be used as raw material for biodiesel synthesis are attractive for the biofuel industry. In this study, the ability to synthesize lipids of Rhodotorula glutinis R4, isolated in Antarctica, was compared with eight strains belonging to the genera Rhodotorula and Yarrowia with the aim of proposing a novel source of oils for biodiesel synthesis. All strains were cultured under nitrogen (N) limiting conditions and an excess of carbon (C) in the culture medium. We found that yeasts accumulated between 9-48.9 % (w/w) of lipids. Among them, R. glutinis R4 showed the highest growth (14 g L-1, µmax 0,092 h-1) and lipid production (7 g L-1; 47 % w/w). Microbial oils produced by R. glutinis R4 are similar to vegetable oils, with 61 % of oleic acid, indicating that it is adequate for biodiesel synthesis. Our results demonstrate that biodiesel derived from R. glutinis R4 complies with international fuel standards ASTM D6751 and EN 14214. Therefore, this work demonstrates that Rhodotorula glutinis R4 is a novel and valuable source of microbial oils for biodiesel synthesis.


Assuntos
Biocombustíveis , Lipídeos/biossíntese , Rhodotorula/metabolismo , Lipídeos/genética , Rhodotorula/genética , Especificidade da Espécie
12.
J Nutr ; 150(4): 704-711, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32060554

RESUMO

BACKGROUND: The association between high selenium (Se) intake and metabolic disorders such as type 2 diabetes has raised great concern, but the underlying mechanism remains unclear. OBJECTIVE: Through targeted metabolomics analysis, we examined the liver sugar and acylcarnitine metabolism responses to supranutritional selenomethionine (SeMet) supplementation in pigs. METHODS: Thirty-six castrated male pigs (Duroc-Landrace-Yorkshire, 62.0 ± 3.3 kg) were fed SeMet adequate (Se-A, 0.25 mg Se/kg) or SeMet supranutritional (Se-S, 2.5 mg Se/kg) diets for 60 d. The Se concentration, biochemical, gene expression, enzyme activity, and energy-targeted metabolite profiles were analyzed. RESULTS: The Se-S group had greater fasting serum concentrations of glucose (1.9-fold), insulin (1.4-fold), and free fatty acids (FFAs,1.3-fold) relative to the Se-A group (P < 0.05). The liver total Se concentration was 4.2-fold that of the Se-A group in the Se-S group (P < 0.05), but expression of most selenoprotein genes and selenoenzyme activity did not differ between the 2 groups. Seven of 27 targeted sugar metabolites and 4 of 21 acylcarnitine metabolites significantly changed in response to high SeMet (P < 0.05). High SeMet supplementation significantly upregulated phosphoenolpyruvate carboxy kinase (PEPCK) activity by 64.4% and decreased hexokinase and succinate dehydrogenase (SDH) activity by 46.5-56.7% (P < 0.05). The relative contents of glucose, dihydroxyacetone phosphate, α-ketoglutarate, fumarate, malate, erythrose-4-phosphate, and sedoheptulose-7-phosphate in the Se-S group were 21.1-360% greater than those in the Se-A group (P < 0.05). The expression of fatty acid synthase (FASN) and the relative contents of carnitine, hexanoyl-carnitine, decanoyl-carnitine, and tetradecanoyl-carnitine in the Se-S group were 35-97% higher than those in the Se-A group (P < 0.05). CONCLUSIONS: Dietary high SeMet-induced hyperglycemia and hyperinsulinemia were associated with suppression of sugar metabolism and elevation of lipid synthesis in pig livers. Our research provides novel insights into high SeMet intake-induced type 2 diabetes.


Assuntos
Carnitina/análogos & derivados , Dieta , Fígado/metabolismo , Selenometionina/administração & dosagem , Açúcares/metabolismo , Animais , Carnitina/metabolismo , Diabetes Mellitus Tipo 2/induzido quimicamente , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Homeostase/efeitos dos fármacos , Hiperglicemia/induzido quimicamente , Hiperinsulinismo/induzido quimicamente , Lipídeos/biossíntese , Fígado/química , Fígado/enzimologia , Masculino , Metabolômica/métodos , Modelos Animais , Oxirredução , RNA Mensageiro/análise , Selênio/administração & dosagem , Selênio/efeitos adversos , Selênio/análise , Selenometionina/efeitos adversos , Selenoproteínas/genética , Sus scrofa
13.
Sci Rep ; 10(1): 294, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941956

RESUMO

The marine pelagic archaeal community is dominated by three major groups, the marine group I (MGI) Thaumarchaeota, and the marine groups II and III (MGII and MGIII) Euryarchaeota. Studies of both MGI cultures and the environment have shown that the MGI core membrane lipids are predominantly composed of glycerol dibiphytanyl glycerol tetraether (GDGT) lipids and the diether lipid archaeol. However, there are no cultured representatives of MGII and III archaea and, therefore, both their membrane lipid composition and potential contribution to the marine archaeal lipid pool remain unknown. Here, we show that GDGTs present in suspended particulate matter of the (sub)surface waters of the North Atlantic Ocean and the coastal North Sea are derived from MGI archaea, and that MGII archaea do not significantly contribute to the pool of GDGTs and archaeol. This implies, in contrast to previous suggestions, that their lipids do not affect the widely used sea surface temperature proxy TEX86. These findings also indicate that MGII archaea are not able to produce any known archaeal lipids, implying that our understanding of the evolution of membrane lipid biosynthesis in Archaea is far from complete.


Assuntos
Archaea/metabolismo , Lipídeos/biossíntese , Archaea/classificação , Archaea/genética , Oceano Atlântico , Cromatografia Líquida de Alta Pressão , Euryarchaeota/classificação , Euryarchaeota/genética , Euryarchaeota/metabolismo , Éteres de Glicerila/análise , Éteres de Glicerila/metabolismo , Lipídeos/análise , Lipídeos/isolamento & purificação , Espectrometria de Massas , Filogenia , RNA Ribossômico 16S/química , RNA Ribossômico 16S/metabolismo , Extração em Fase Sólida
14.
Appl Microbiol Biotechnol ; 104(6): 2639-2649, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31980919

RESUMO

Microbial oils are lipids produced by oleaginous microorganisms, which can be used as a potential feedstock for oleochemical production. The oleaginous yeast Rhodotorula toruloides can co-produce microbial oils and high-value compounds from low-cost substrates, such as xylose and acetic acid (from hemicellulosic hydrolysates) and raw glycerol (a byproduct of biodiesel production). One step towards economic viability is identifying the best conditions for lipid production, primarily the most suitable carbon-to-nitrogen ratio (C/N). Here, we aimed to identify the best conditions and cultivation mode for lipid production by R. toruloides using various low-cost substrates and a range of C/N ratios (60, 80, 100, and 120). Turbidostat mode was used to achieve a steady state at the maximal specific growth rate and to avoid continuously changing environmental conditions (i.e., C/N ratio) that inherently occur in batch mode. Regardless of the carbon source, higher C/N ratios increased lipid yields (up to 60% on xylose at a C/N of 120) but decreased the specific growth rate. Growth on glycerol resulted in the highest specific growth and lipid production (0.085 g lipids/gDW*h) rates at C/Ns between 60 and 100. We went on to study lipid production using glycerol in both batch and fed-batch modes, which resulted in lower specific lipid production rates compared with turbisdostat, however, fed batch is superior in terms of biomass production and lipid titers. By combining the data we obtained in these experiments with a genome-scale metabolic model of R. toruloides, we identified targets for improvements in lipid production that could be carried out either by metabolic engineering or process optimization.


Assuntos
Carbono/metabolismo , Lipídeos/biossíntese , Nitrogênio/metabolismo , Rhodotorula/metabolismo , Biomassa , Glucose/metabolismo , Glicerol/metabolismo , Microbiologia Industrial , Engenharia Metabólica
15.
Nat Commun ; 11(1): 341, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31953403

RESUMO

Milk lipid secretion is a critical process for the delivery of nutrition and energy from parent to offspring. However, the underlying molecular mechanism is less clear. Here we report that TDP-43, a RNA-binding protein, underwent positive selection in the mammalian lineage. Furthermore, TDP-43 gene (Tardbp) loss induces accumulation of large lipid droplets and severe lipid secretion deficiency in mammary epithelial cells to outside alveolar lumens, eventually resulting in lactation failure and pup starvation within three weeks postpartum. In human milk samples from lactating women, the expression levels of TDP-43 is positively correlated with higher milk output. Mechanistically, TDP-43 exerts post-transcriptional regulation of Btn1a1 and Xdh mRNA stability, which are required for the secretion of lipid droplets from epithelial cells to the lumen. Taken together, our results highlights the critical role of TDP-43 in milk lipid secretion, providing a potential strategy for the screening and intervention of clinical lactation insufficiency.


Assuntos
Butirofilinas/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Lactação/fisiologia , Lipídeos/biossíntese , Xantina Desidrogenase/metabolismo , Animais , Mama/metabolismo , Células Epiteliais/metabolismo , Feminino , Humanos , Transtornos da Lactação/genética , Gotículas Lipídicas/metabolismo , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Camundongos , Camundongos Knockout , Leite/metabolismo , RNA Mensageiro/metabolismo , Transcriptoma
16.
Molecules ; 25(2)2020 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-31936538

RESUMO

Microalgae are freshwater and marine unicellular photosynthetic organisms that utilize sunlight to produce biomass. Due to fast microalgal growth rate and their unique biochemical profiles and potential applications in food and renewable energy industries, the interest in microalgal research is rapidly increasing. Biochemical and genetic engineering have been considered to improve microalgal biomass production but these manipulations also limited microalgal growth. The aim of the study was the biochemical characterization of recently identified microalgal strain Planktochlorella nurekis with elevated cell size and DNA levels compared to wild type strain that was achieved by a safe non-vector approach, namely co-treatment with colchicine and cytochalasin B (CC). A slight increase in growth rate was observed in twelve clones of CC-treated cells. For biochemical profiling, several parameters were considered, namely the content of proteins, amino acids, lipids, fatty acids, ß-glucans, chlorophylls, carotenoids, B vitamins and ash. CC-treated cells were characterized by elevated levels of lipids compared to unmodified cells. Moreover, the ratio of carotenoids to chlorophyll a and total antioxidant capacity were slightly increased in CC-treated cells. We suggest that Planktochlorella nurekis with modified DNA levels and improved lipid content can be considered to be used as a dietary supplement and biofuel feedstock.


Assuntos
Biomassa , DNA/química , Lipídeos/genética , Microalgas/genética , Biocombustíveis , Clorofila A/biossíntese , Clorofila A/química , DNA/genética , Lipídeos/biossíntese , Lipídeos/química , Microalgas/química , Microalgas/metabolismo , Fotossíntese/genética
17.
J Biosci Bioeng ; 129(6): 687-692, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31937470

RESUMO

Production of biofuels and fine chemicals from biomass-derived carbohydrates through biorefinery attracts much attention because it is recognized as an environmentally friendly process. Microalgae can serve as promising carbohydrate producers for biorefinery rather than woody and crop biomass due to high biomass productivity, high CO2 fixation, and no competition with food production. However, microalgae with high carbohydrate productivity have not been well investigated despite intensive studies of microalgal lipid production. In this study, the carbohydrate production of Pseudoneochloris sp. strain NKY372003 isolated as a high carbohydrate producer, was investigated. Cultivation conditions with various combinations of nutrient contents and photon flux density were examined to maximize the biomass and carbohydrate productivities. At the optimal condition, the biomass and carbohydrate production of this strain reached 8.11 ± 0.37 g/L and 5.5 ± 0.2 g/L, respectively. As far as we know, this is the highest carbohydrate production by microalgae among ever reported. Cell staining with Lugol's solution visualized intracellular starch granules. Because algal starch can be converted to biofuels and building blocks of fine chemicals, Pseudoneochloris sp. NKY372003 will be a promising candidate for production of fermentable carbohydrates towards biofuels and fine chemicals production.


Assuntos
Clorófitas/metabolismo , Biocombustíveis , Biomassa , Metabolismo dos Carboidratos , Carboidratos/química , Lipídeos/biossíntese , Microalgas/química
18.
Am J Physiol Endocrinol Metab ; 318(3): E357-E370, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31935113

RESUMO

Intramuscular triglycerides (IMTG) are a key substrate during prolonged exercise, but little is known about the rate of IMTG resynthesis in the postexercise period. We investigated the hypothesis that the distribution of the lipid droplet (LD)-associated perilipin (PLIN) proteins is linked to IMTG storage following exercise. Fourteen elite male triathletes (27 ± 1 yr, 66.5 ± 1.3 mL·kg-1·min-1) completed 4 h of moderate-intensity cycling. During the first 4 h of recovery, subjects received either carbohydrate or H2O, after which both groups received carbohydrate. Muscle biopsies collected pre- and postexercise and 4 and 24 h postexercise were analyzed using confocal immunofluorescence microscopy for fiber type-specific IMTG content and PLIN distribution with LDs. Exercise reduced IMTG content in type I fibers (-53%, P = 0.002), with no change in type IIa fibers. During the first 4 h of recovery, IMTG content increased in type I fibers (P = 0.014), but was not increased more after 24 h, where it was similar to baseline levels in both conditions. During recovery the number of LDs labeled with PLIN2 (70%), PLIN3 (63%), and PLIN5 (62%; all P < 0.05) all increased in type I fibers. Importantly, the increase in LDs labeled with PLIN proteins only occurred at 24 h postexercise. In conclusion, IMTG resynthesis occurs rapidly in type I fibers following prolonged exercise in highly trained individuals. Furthermore, increases in IMTG content following exercise preceded an increase in the number of LDs labeled with PLIN proteins. These data, therefore, suggest that the PLIN proteins do not play a key role in postexercise IMTG resynthesis.


Assuntos
Atletas , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos/fisiologia , Lipídeos/biossíntese , Músculo Esquelético/fisiologia , Perilipinas/metabolismo , Adulto , Ciclismo/fisiologia , Biópsia , Exercício Físico/fisiologia , Humanos , Masculino , Fibras Musculares de Contração Lenta/fisiologia , Perilipina-2/genética , Perilipina-2/metabolismo , Perilipina-3/genética , Perilipina-3/metabolismo , Perilipina-5/genética , Perilipina-5/metabolismo , Resistência Física , Triglicerídeos/metabolismo , Adulto Jovem
19.
Chemosphere ; 247: 125814, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31927186

RESUMO

The extreme high CO2 in industrial exhaust gas cannot be tolerated by microalgae is the key challenge for the application of microalgae in CO2 bio-sequestration. To provide better insights for this challenge, we chose one high CO2 tolerant (Chlorella sp. LAMB 31) and non-tolerant (Chlorella sp. LAMB 122) Chlorella sp. to examine their different CO2 fixation and carbon allocation responses to 40% CO2. The results indicated LAMB 31 had a 24-h "lag phase" of biomass increase, during which the transition from PSII-PSI and the increase of lipid synthesis happened to acclimate high CO2 conditions, followed by the increase of pigments synthesis, carbon fixation rates and polysaccharide productions. However, no acclimating mechanism was observed in LAMB 122, whose biomass, photosynthesis and material synthesis were all gradually collapsed under 40% CO2. Finally, four parameters including Chl a, polysaccharides, carbon fixation rates and MDA were selected to be good physiological biomarkers for high CO2 tolerant strains screenings in the future.


Assuntos
Biomassa , Ciclo do Carbono , Dióxido de Carbono/metabolismo , Carbono/metabolismo , Chlorella/metabolismo , Lipídeos/biossíntese , Microalgas/metabolismo , Fotossíntese , Polissacarídeos/biossíntese , Especificidade da Espécie
20.
Nat Commun ; 11(1): 438, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31974378

RESUMO

Dysfunction of invariant natural killer T (iNKT) cells in tumor microenvironment hinders their anti-tumor efficacy, and the underlying mechanisms remain unclear. Here we report that iNKT cells increase lipid biosynthesis after activation, and that is promoted by PPARγ and PLZF synergically through enhancing transcription of Srebf1. Among those lipids, cholesterol is required for the optimal IFN-γ production from iNKT cells. Lactic acid in tumor microenvironment reduces expression of PPARγ in intratumoral iNKT cells and consequently diminishes their cholesterol synthesis and IFN-γ production. Importantly, PPARγ agonist pioglitazone, a thiazolidinedione drug for type 2 diabetes, successfully restores IFN-γ production in tumor-infiltrating iNKT cells from both human patients and mouse models. Combination of pioglitazone and alpha-galactosylceramide treatments significantly enhances iNKT cell-mediated anti-tumor immune responses and prolongs survival of tumor-bearing mice. Our studies provide a strategy to augment the anti-tumor efficacy of iNKT cell-based immunotherapies via promoting their lipid biosynthesis.


Assuntos
Imunoterapia/métodos , Lipídeos/biossíntese , Células T Matadoras Naturais/fisiologia , Microambiente Tumoral/imunologia , Animais , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Colesterol/metabolismo , Galactosilceramidas/farmacologia , Regulação da Expressão Gênica , Humanos , Interferon gama/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Melanoma Experimental/imunologia , Melanoma Experimental/patologia , Camundongos Endogâmicos C57BL , Células T Matadoras Naturais/efeitos dos fármacos , Células T Matadoras Naturais/patologia , PPAR gama/genética , PPAR gama/metabolismo , Pioglitazona/farmacologia , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Microambiente Tumoral/efeitos dos fármacos
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