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1.
Commun Biol ; 5(1): 164, 2022 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-35210545

RESUMO

Quantification of system dynamics is a central aim of mathematical modelling in biology. Defining experimentally supported functional relationships between molecular entities by mathematical terms enables the application of computational routines to simulate and analyse the underlying molecular system. In many fields of natural sciences and engineering, trigonometric functions are applied to describe oscillatory processes. As biochemical oscillations occur in many aspects of biochemistry and biophysics, Fourier analysis of metabolic functions promises to quantify, describe and analyse metabolism and its reaction towards environmental fluctuations. Here, Fourier polynomials were developed from experimental time-series data and combined with block diagram simulation of plant metabolism to study heat shock response of photosynthetic CO2 assimilation and carbohydrate metabolism in Arabidopsis thaliana. Simulations predicted a stabilising effect of reduced sucrose biosynthesis capacity and increased capacity of starch biosynthesis on carbon assimilation under transient heat stress. Model predictions were experimentally validated by quantifying plant growth under such stress conditions. In conclusion, this suggests that Fourier polynomials represent a predictive mathematical approach to study dynamic plant-environment interactions.


Assuntos
Proteínas de Arabidopsis , Proteínas de Arabidopsis/metabolismo , Carbono/metabolismo , Folhas de Planta , Sacarose/metabolismo , Temperatura
2.
Nat Commun ; 13(1): 5243, 2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36068201

RESUMO

Methanol is a liquid with high energy storage capacity that holds promise as an alternative substrate to replace sugars in the biotechnology industry. It can be produced from CO2 or methane and its use does not compete with food and animal feed production. However, there are currently only limited biotechnological options for the valorization of methanol, which hinders its widespread adoption. Here, we report the conversion of the industrial platform organism Escherichia coli into a synthetic methylotroph that assimilates methanol via the energy efficient ribulose monophosphate cycle. Methylotrophy is achieved after evolution of a methanol-dependent E. coli strain over 250 generations in continuous chemostat culture. We demonstrate growth on methanol and biomass formation exclusively from the one-carbon source by 13C isotopic tracer analysis. In line with computational modeling, the methylotrophic E. coli strain optimizes methanol oxidation by upregulation of an improved methanol dehydrogenase, increasing ribulose monophosphate cycle activity, channeling carbon flux through the Entner-Doudoroff pathway and downregulating tricarboxylic acid cycle enzymes. En route towards sustainable bioproduction processes, our work lays the foundation for the efficient utilization of methanol as the dominant carbon and energy resource.


Assuntos
Escherichia coli , Metanol , Carbono/metabolismo , Escherichia coli/genética , Engenharia Metabólica , Metanol/metabolismo , Pentoses
3.
Front Cell Infect Microbiol ; 12: 958555, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36072222

RESUMO

Treatment of Mycobacterium tuberculosis (Mtb) infections is particularly arduous. One challenge to effectively treating tuberculosis is that drug efficacy in vivo often fails to match drug efficacy in vitro. This is due to multiple reasons, including inadequate drug concentrations reaching Mtb at the site of infection and physiological changes of Mtb in response to host derived stresses that render the bacteria more tolerant to antibiotics. To more effectively and efficiently treat tuberculosis, it is necessary to better understand the physiologic state of Mtb that promotes drug tolerance in the host. Towards this end, multiple studies have converged on bacterial central carbon metabolism as a critical contributor to Mtb drug tolerance. In this review, we present the evidence that changes in central carbon metabolism can promote drug tolerance, depending on the environment surrounding Mtb. We posit that these metabolic pathways could be potential drug targets to stymie the development of drug tolerance and enhance the efficacy of current antimicrobial therapy.


Assuntos
Mycobacterium tuberculosis , Tuberculose dos Linfonodos , Carbono/metabolismo , Tolerância a Medicamentos , Humanos , Redes e Vias Metabólicas
4.
Sci Rep ; 12(1): 14949, 2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36056039

RESUMO

Bacterial degradation of sinking diatom aggregates is key for the availability of organic matter in the deep-ocean. Yet, little is known about the impact of aggregate colonization by different bacterial taxa on organic carbon and nutrient cycling within aggregates. Here, we tracked the carbon (C) and nitrogen (N) transfer from the diatom Leptocylindrus danicus to different environmental bacterial groups using a combination of 13C and 15N isotope incubation (incubated for 72 h), CARD-FISH and nanoSIMS single-cell analysis. Pseudoalteromonas bacterial group was the first colonizing diatom-aggregates, succeeded by the Alteromonas group. Within aggregates, diatom-attached bacteria were considerably more enriched in 13C and 15N than non-attached bacteria. Isotopic mass balance budget indicates that both groups showed comparable levels of diatom C in their biomass, accounting for 19 ± 7% and 15 ± 11%, respectively. In contrast to C, bacteria of the Alteromonas groups showed significantly higher levels of N derived from diatoms (77 ± 28%) than Pseudoalteromonas (47 ± 17%), suggesting a competitive advantage for Alteromonas in the N-limiting environments of the deep-sea. Our results imply that bacterial succession within diatom aggregates may largely impact taxa-specific C and N uptake, which may have important consequences for the quantity and quality of organic matter exported to the deep ocean.


Assuntos
Diatomáceas , Bactérias/metabolismo , Biomassa , Carbono/metabolismo , Diatomáceas/metabolismo , Nitrogênio/metabolismo
5.
Ying Yong Sheng Tai Xue Bao ; 33(7): 1901-1910, 2022 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-36052794

RESUMO

To determine the mitigating effects of exogenous melatonin on salt-alkali stress in cucumber, we mea-sured photosynthetic characteristics and osmoregulatory substance content of cucumber leaves under salt-alkali stress, using 'Xinchun 4' cucumber as the test material and a salt-alkali complex (NaCl:Na2SO4:Na2CO3:NaHCO3 = 1:9:1:9) to simulate stress. The results showed that compared with the normal seedlings, the exogenous application of 10 µmol·L-1 melatonin significantly increased the contents of chlorophyll, soluble sugar, and soluble protein, as well as net photosynthetic rate, stomatal conductance, transpiration rate, photosystem Ⅱ maximum photochemical efficiency, actual photochemical efficiency, apparent photosynthetic electron transfer rate, and photochemical burst coefficient of cucumber seedlings under 40 mmol·L-1 salt-alkali stress, but decreased intercellular CO2 concentration, non-photochemical burst coefficient, and sucrose, fructose, starch, and proline contents by 11.1%, 13.8%, 12.7%, 27.5%, 1.3% and 32.8%, respectively. Moreover, the activities of key enzymes for carbon assimilation (including ribulose-1,5-bisphosphate carboxylase/oxygenase and fructose-1,6-bisphosphate esterase) were significantly increased, whereas the mRNA expression levels of Rubisco subunits (CsrbcS and CsrbcL), CsFBA, CsRCA, CsFBPase and CsTK were downregulated. In conclusion, exogenous melatonin could increase the contents of chlorophyll and osmoregulatory substance, photosynthetic chemical efficiency, and key carbon assimilation enzyme activities of cucumber seedlings under salt-alkali stress, thereby enhance photosynthetic capacity and reduce the stress-induced plant damage. The results would provide theoretical basis for anti-saline plant cultivation.


Assuntos
Cucumis sativus , Melatonina , Álcalis , Carbono/metabolismo , Clorofila/metabolismo , Frutose/metabolismo , Frutose/farmacologia , Melatonina/farmacologia , Fotossíntese , Folhas de Planta/metabolismo , Plântula , Cloreto de Sódio/farmacologia
6.
Acta Crystallogr D Struct Biol ; 78(Pt 9): 1171-1179, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36048156

RESUMO

Ketosynthases (KSs) catalyse essential carbon-carbon bond-forming reactions in fatty-acid biosynthesis using a two-step, ping-pong reaction mechanism. In Escherichia coli, there are two homodimeric elongating KSs, FabB and FabF, which possess overlapping substrate selectivity. However, FabB is essential for the biosynthesis of the unsaturated fatty acids (UFAs) required for cell survival in the absence of exogenous UFAs. Additionally, FabB has reduced activity towards substrates longer than 12 C atoms, whereas FabF efficiently catalyses the elongation of saturated C14 and unsaturated C16:1 acyl-acyl carrier protein (ACP) complexes. In this study, two cross-linked crystal structures of FabB in complex with ACPs functionalized with long-chain fatty-acid cross-linking probes that approximate catalytic steps were solved. Both homodimeric structures possess asymmetric substrate-binding pockets suggestive of cooperative relationships between the two FabB monomers when engaged with C14 and C16 acyl chains. In addition, these structures capture an unusual rotamer of the active-site gating residue, Phe392, which is potentially representative of the catalytic state prior to substrate release. These structures demonstrate the utility of mechanism-based cross-linking methods to capture and elucidate conformational transitions accompanying KS-mediated catalysis at near-atomic resolution.


Assuntos
3-Oxoacil-(Proteína de Transporte de Acila) Sintase , Proteínas de Escherichia coli , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/química , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/metabolismo , Carbono/metabolismo , Catálise , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Ácido Graxo Sintase Tipo II , Ácidos Graxos Insaturados/metabolismo
7.
Food Res Int ; 160: 111478, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36076369

RESUMO

To optimize vineyard management practices to adapt viticulture to climate change, knowledge of the regulation mechanism of metabolite accumulation under carbon source limitation and abscisic acid (ABA) application in grapes should be deepened. Here, carbon source limitations were imposed by reducing leaf area from 12 to 2 leaves per vine (at pea sized stage, - 2L-P; or one week prior to veraison - 2L-V) and phloem girdling between the second and third leaf from bottom to top (one week prior to veraison - 12L-girdling) were compared for their effects on berry composition. All three modalities significantly reduced sugar, anthocyanin and ABA content in comparison with berries under sufficient carbon supply (12 leaves per vine - 12L), with 2L-V being the greatest. Allowing leaf area to partially recover (2L-R) or berry ABA application (400 mg. L-1) one week before veraison increased the ratio of anthocyanin to sugar under source limitation. Combined with the analysis of berry metabolites and transcript abundances, our results indicate that source limitation and exogenous ABA co-regulated anthocyanins content through differential gene expression.


Assuntos
Vitis , Ácido Abscísico , Antocianinas/metabolismo , Carboidratos , Carbono/metabolismo , Frutas/metabolismo , Açúcares/metabolismo , Vitis/metabolismo
8.
Water Res ; 223: 119033, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36058096

RESUMO

External stimulus such as light irradiation is able to deteriorate intracellular redox homeostasis and induce photooxidative damage to non-photogenic bacteria. Exploiting effective strategies to help bacteria resisting infaust stress is meaningful for achieving a stable operation of biological treatment system. In this work, selenium-doped carbon quantum dots (Se-CQDs) were blended into anaerobic ammonia oxidation (anammox) bacteria and an inorganic nanoparticle-microbe hybrid was successfully fabricated to evaluate its nitrogen removal performance under solar-simulated irradiation. It was found that the specific anammox activity decreased by 29.7 ± 5.2% and reactive oxygen species (ROS) content increased by 134.8 ± 4.1% under 50,000 lux light. Sludge activity could be completely recovered under the optimum dosage of 0.42 mL·(g volatile suspended solid) -1 Se-CQDs. Hydroxyl radical (·OH) and superoxide anion radical (·O2-) were identified as the leading ROS inducing lipid peroxidation and antioxidase function detriment. Also, the structure of ladderane lipids located on anammoxosome was destroyed by ROS and functional genes abundances declined accordingly. Although cell surface coated Se-CQDs could absorb ultraviolet light and partially mitigated the photoinhibition, the direct scavenging of ROS by intracellular Se-CQDs primarily contributed to the cellular redox homeostasis, antioxidase activity recovery and sludge activity improvement. The findings of this work provide in-depth understanding the metabolic response mechanism of anammox consortia to light irradiation and might be valuable for a more stable and sustainable nitrogen removal technology, i.e., algal-bacterial symbiotic system, development.


Assuntos
Pontos Quânticos , Selênio , Oxidação Anaeróbia da Amônia , Anaerobiose , Bactérias/metabolismo , Reatores Biológicos/microbiologia , Carbono/metabolismo , Radical Hidroxila/metabolismo , Lipídeos , Nitrogênio/metabolismo , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Selênio/metabolismo , Esgotos/microbiologia , Superóxidos
9.
Plant Signal Behav ; 17(1): 2115634, 2022 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-36102341

RESUMO

Plant organisms assimilate CO2 through the photosynthetic pathway, which facilitates in the synthesis of sugar for plant development. As environmental elements including water level, CO2 concentration, temperature and soil characteristics change, the plants may recruit series of genes to help adapt the hostile environments and challenges. C4 photosynthesis plants are an excellent example of plant evolutionary adaptation to diverse condition. Compared with C3 photosynthesis plants, C4 photosynthesis plants have altered leaf anatomy and new metabolism for CO2 capture, with multiple related enzymes such as phosphoenolpyruvate carboxylase (PEPCase), pyruvate orthophosphate dikinase (PPDK), NAD(P)-malic enzyme (NAD(P)-ME), NAD(P) - malate dehydrogenase (NAD(P)-MDH) and carbonic anhydrases (CA), identified to participate in the carbon concentrating mechanism (CCM) pathway. Recently, great achievements about C4 CCM-related genes have been made in the dissection of C3 plant development processes involving various stresses. In this review, we describe the functions of C4 CCM-related homologous genes in carbon and nitrogen metabolism in C3 plants. We further summarize C4 CCM-related homologous genes' functions in response to stresses in C3 plants. The understanding of C4 CCM-related genes' function in response to abiotic stress in plant is important to modify the crop plants for climate diversification.


Assuntos
Dióxido de Carbono , NAD , Carbono/metabolismo , Dióxido de Carbono/metabolismo , NAD/metabolismo , Fosfoenolpiruvato Carboxilase/genética , Fosfoenolpiruvato Carboxilase/metabolismo , Plantas/genética , Plantas/metabolismo , Estresse Fisiológico/genética
10.
PLoS Pathog ; 18(9): e1010766, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36067266

RESUMO

Wound infections are often polymicrobial in nature, biofilm associated and therefore tolerant to antibiotic therapy, and associated with delayed healing. Escherichia coli and Staphylococcus aureus are among the most frequently cultured pathogens from wound infections. However, little is known about the frequency or consequence of E. coli and S. aureus polymicrobial interactions during wound infections. Here we show that E. coli kills Staphylococci, including S. aureus, both in vitro and in a mouse excisional wound model via the genotoxin, colibactin. Colibactin biosynthesis is encoded by the pks locus, which we identified in nearly 30% of human E. coli wound infection isolates. While it is not clear how colibactin is released from E. coli or how it penetrates target cells, we found that the colibactin intermediate N-myristoyl-D-Asn (NMDA) disrupts the S. aureus membrane. We also show that the BarA-UvrY two component system (TCS) senses the environment created during E. coli and S. aureus mixed species interaction, leading to upregulation of pks island genes. Further, we show that BarA-UvrY acts via the carbon storage global regulatory (Csr) system to control pks expression. Together, our data demonstrate the role of colibactin in interspecies competition and show that it is regulated by BarA-UvrY TCS during interspecies competition.


Assuntos
Infecções por Escherichia coli , Proteínas de Escherichia coli , Policetídeos , Infecção dos Ferimentos , Animais , Antibacterianos/metabolismo , Carbono/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Humanos , Proteínas de Membrana/metabolismo , Camundongos , Mutagênicos/metabolismo , N-Metilaspartato/metabolismo , Peptídeos , Fosfotransferases/genética , Policetídeos/metabolismo , Staphylococcus/metabolismo , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Fatores de Transcrição/metabolismo
11.
Int J Mol Sci ; 23(17)2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36077396

RESUMO

Exogenous Gln as a single N source has been shown to exert similar roles to the inorganic N in poplar 'Nanlin895' in terms of growth performance, yet the underlying molecular mechanism remains unclear. Herein, transcriptome analyses of both shoots (L) and roots (R) of poplar 'Nanlin895' fertilized with Gln (G) or the inorganic N (control, C) were performed. Compared with the control, 3109 differentially expressed genes (DEGs) and 5071 DEGs were detected in the GL and GR libraries, respectively. In the shoots, Gln treatment resulted in downregulation of a large number of ribosomal genes but significant induction of many starch and sucrose metabolism genes, demonstrating that poplars tend to distribute more energy to sugar metabolism rather than ribosome biosynthesis when fertilized with Gln-N. By contrast, in the roots, most of the DEGs were annotated to carbon metabolism, glycolysis/gluconeogenesis and phenylpropanoid biosynthesis, suggesting that apart from N metabolism, exogenous Gln has an important role in regulating the redistribution of carbon resources and secondary metabolites. Therefore, it can be proposed that the promotion impact of Gln on poplar growth and photosynthesis may result from the improvement of both carbon and N allocation, accompanied by an efficient energy switch for growth and stress responses.


Assuntos
Carbono , Populus , Carbono/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Glutamina/metabolismo , Populus/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Transcriptoma
12.
Microb Cell Fact ; 21(1): 189, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-36100849

RESUMO

BACKGROUND: The modification of glucose import capacity is an engineering strategy that has been shown to improve the characteristics of Escherichia coli as a microbial factory. A reduction in glucose import capacity can have a positive effect on production strain performance, however, this is not always the case. In this study, E. coli W3110 and a group of four isogenic derivative strains, harboring single or multiple deletions of genes encoding phosphoenolpyruvate:sugar phosphotransferase system (PTS)-dependent transporters as well as non-PTS transporters were characterized by determining their transcriptomic response to reduced glucose import capacity. RESULTS: These strains were grown in bioreactors with M9 mineral salts medium containing 20 g/L of glucose, where they displayed specific growth rates ranging from 0.67 to 0.27 h-1, and specific glucose consumption rates (qs) ranging from 1.78 to 0.37 g/g h. RNA-seq analysis revealed a transcriptional response consistent with carbon source limitation among all the mutant strains, involving functions related to transport and metabolism of alternate carbon sources and characterized by a decrease in genes encoding glycolytic enzymes and an increase in gluconeogenic functions. A total of 107 and 185 genes displayed positive and negative correlations with qs, respectively. Functions displaying positive correlation included energy generation, amino acid biosynthesis, and sugar import. CONCLUSION: Changes in gene expression of E. coli strains with impaired glucose import capacity could be correlated with qs values and this allowed an inference of the physiological state of each mutant. In strains with lower qs values, a gene expression pattern is consistent with energy limitation and entry into the stationary phase. This physiological state could explain why these strains display a lower capacity to produce recombinant protein, even when they show very low rates of acetate production. The comparison of the transcriptomes of the engineered strains employed as microbial factories is an effective approach for identifying favorable phenotypes with the potential to improve the synthesis of biotechnological products.


Assuntos
Proteínas de Escherichia coli , Escherichia coli , Carbono/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Perfilação da Expressão Gênica , Glucose/metabolismo , Açúcares/metabolismo
13.
Microb Cell Fact ; 21(1): 190, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-36104783

RESUMO

BACKGROUND: Eukaryotic algae have recently emerged as hosts for metabolic engineering efforts to generate heterologous isoprenoids. Isoprenoid metabolic architectures, flux, subcellular localization, and transport dynamics have not yet been fully elucidated in algal hosts. RESULTS: In this study, we investigated the accessibility of different isoprenoid precursor pools for C15 sesquiterpenoid generation in the cytoplasm and chloroplast of Chlamydomonas reinhardtii using the Abies grandis bisabolene synthase (AgBS) as a reporter. The abundance of the C15 sesquiterpene precursor farnesyl pyrophosphate (FPP) was not increased in the cytosol by co-expression and fusion of AgBS with different FPP synthases (FPPSs), indicating limited C5 precursor availability in the cytoplasm. However, FPP was shown to be available in the plastid stroma, where bisabolene titers could be improved several-fold by FPPSs. Sesquiterpene production was greatest when AgBS-FPPS fusions were directed to the plastid and could further be improved by increasing the gene dosage. During scale-up cultivation with different carbon sources and light regimes, specific sesquiterpene productivities from the plastid were highest with CO2 as the only carbon source and light:dark illumination cycles. Potential prenyl unit transporters are proposed based on bioinformatic analyses, which may be in part responsible for our observations. CONCLUSIONS: Our findings indicate that the algal chloroplast can be harnessed in addition to the cytosol to exploit the full potential of algae as green cell factories for non-native sesquiterpenoid generation. Identification of a prenyl transporter may be leveraged for further extending this capacity.


Assuntos
Chlamydomonas reinhardtii , Microalgas , Sesquiterpenos , Carbono/metabolismo , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/metabolismo , Microalgas/metabolismo , Neopreno , Plantas , Fosfatos de Poli-Isoprenil , Sesquiterpenos/metabolismo , Terpenos/metabolismo
14.
Molecules ; 27(16)2022 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-36014568

RESUMO

The current output of an anodic bioelectrochemical system (BES) depends upon the extracellular electron transfer (EET) rate from electricigens to the electrodes. Thus, investigation of EET mechanisms between electricigens and solid electrodes is essential. Here, reticulated vitreous carbon (RVC) electrodes are used to increase the surface available for biofilm formation of the known electricigen Shewanella loihica PV-4, which is limited in conventional flat electrodes. S. loihica PV-4 utilizes flavin-mediated EET at potential lower than the outer membrane cytochromes (OMC), while at higher potential, both direct electron transfer (DET) and mediated electron transfer (MET) contribute to the current output. Results show that high electrode potential favors cell attachment on RVC, which enhances the current output. DET is the prevailing mechanism in early biofilm, while the contribution of MET to current output increased as the biofilm matured. Electrochemical analysis under starvation shows that the mediators could be confined in the biofilm. The morphology of biofilm shows bacteria distributed on the top layer of honeycomb structures, preferentially on the flat areas. This study provides insights into the EET pathways of S. loihica PV-4 on porous RVC electrodes at different biofilm ages and different set potential, which is important for the design of real-world BES.


Assuntos
Fontes de Energia Bioelétrica , Shewanella , Fontes de Energia Bioelétrica/microbiologia , Carbono/metabolismo , DEET , Eletrodos , Transporte de Elétrons , Shewanella/química
15.
Mar Drugs ; 20(8)2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-36005511

RESUMO

Docosahexaenoic acid (DHA) is an omega-3 polyunsaturated fatty acid (PUFA) that is critical for the intelligence and visual development of infants. Crypthecodinium is the first microalga approved by the Food and Drug Administration for DHA production, but its relatively high intracellular starch content restricts fatty acid accumulation. In this study, different carbon sources, including glucose (G), sodium acetate (S) and mixed carbon (M), were used to investigate the regulatory mechanisms of intracellular organic carbon distribution in Crypthecodinium sp. SUN. Results show that glucose favored cell growth and starch accumulation. Sodium acetate limited glucose utilization and starch accumulation but caused a significant increase in total fatty acid (TFA) accumulation and the DHA percentage. Thus, the DHA content in the S group was highest among three groups and reached a maximum (10.65% of DW) at 96 h that was 2.92-fold and 2.24-fold of that in the G and M groups, respectively. Comparative transcriptome analysis showed that rather than the expression of key genes in fatty acids biosynthesis, increased intracellular acetyl-CoA content appeared to be the key regulatory factor for TFA accumulation. Additionally, metabolome analysis showed that the accumulated DHA-rich metabolites of lipid biosynthesis might be the reason for the higher TFA content and DHA percentage of the S group. The present study provides valuable insights to guide further research in DHA production.


Assuntos
Dinoflagelados , Microalgas , Carbono/metabolismo , Dinoflagelados/metabolismo , Ácidos Docosa-Hexaenoicos , Ácidos Graxos/metabolismo , Glucose/metabolismo , Humanos , Microalgas/metabolismo , Sódio/metabolismo , Acetato de Sódio/metabolismo , Amido/metabolismo
16.
Sci Rep ; 12(1): 14255, 2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-35995803

RESUMO

Cystic fibrosis is an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) that can lead to terminal respiratory failure. Ultrafine carbonaceous particles, which are ubiquitous in ambient urban and indoor air, are increasingly considered as major contributors to the global health burden of air pollution. However, their effects on the expression of CFTR and associated genes in lung epithelial cells have not yet been investigated. We therefore evaluated the effects of carbon nanoparticles (CNP), generated by spark-ablation, on the human bronchial epithelial cell line 16HBE14o- at air-liquid interface (ALI) culture conditions. The ALI-cultured cells exhibited epithelial barrier integrity and increased CFTR expression. Following a 4-h exposure to CNP, the cells exhibited a decreased barrier integrity, as well as decreased expression of CFTR transcript and protein levels. Furthermore, transcriptomic analysis revealed that the CNP-exposed cells showed signs of oxidative stress, apoptosis and DNA damage. In conclusion, this study describes spark-ablated carbon nanoparticles in a realistic exposure of aerosols to decrease CFTR expression accompanied by transcriptomic signs of oxidative stress, apoptosis and DNA damage.


Assuntos
Fibrose Cística , Nanopartículas , Brônquios/metabolismo , Carbono/metabolismo , Fibrose Cística/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Células Epiteliais/metabolismo , Humanos , Nanopartículas/toxicidade , Material Particulado/metabolismo
17.
Sci Rep ; 12(1): 13999, 2022 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-35978100

RESUMO

Water vapor increases the electrical conductivity of silk cocoons, human hair, jute, and corn silk. This phenomenon is unclear. In the present study, XPS analysis of cocoons showed that water vapor reduces the surface presence of low-energy carbon species (C-C, C-H). In contrast, electron-dense, high-energy carbon species (C-N, C=C, C=O) remained unchanged, possibly enhancing surface charge hopping. While water vapor improves the conduction, the deficiency of charge carrier diminishes the effect. We increase the charge carrier by soaking the cocoon in an aqueous solution of common salt (NaCl) to amplify the current. Salt treatment followed by 2-min exposure to water vapor results in a sharp upward spike in the current (3.6 ± 1.07 mA, n = 12; mean ± SE) from the baseline (0.06 ± 0.02 mA, n = 12). After 1 h, it maintains an average value of 0.39 ± 0.12 mA; n = 12, indicating an upward shift in the baseline. Every time the cocoon charges with water vapor, the next charging cycle initiates after the cocoon dries up. Inspired by the cocoon ecology, we demonstrate an alternating 'water vapor-dry air' cycle for rapid charging and discharging of the cocoon battery. Finally, we designed a prototype of a self-lighting kettle and water-vapor panels for futuristic homes using a 'brine-silk cocoon protein bio-battery,' where moist waste heat generates electricity.


Assuntos
Bombyx , Seda , Animais , Bombyx/metabolismo , Carbono/metabolismo , Humanos , Iluminação , Sais , Seda/metabolismo , Vapor
18.
Science ; 377(6606): 603-608, 2022 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-35926033

RESUMO

Grasslands store approximately one third of the global terrestrial carbon stocks and can act as an important soil carbon sink. Recent studies show that plant diversity increases soil organic carbon (SOC) storage by elevating carbon inputs to belowground biomass and promoting microbial necromass contribution to SOC storage. Climate change affects grassland SOC storage by modifying the processes of plant carbon inputs and microbial catabolism and anabolism. Improved grazing management and biodiversity restoration can provide low-cost and/or high-carbon-gain options for natural climate solutions in global grasslands. The achievable SOC sequestration potential in global grasslands is 2.3 to 7.3 billion tons of carbon dioxide equivalents per year (CO2e year-1) for biodiversity restoration, 148 to 699 megatons of CO2e year-1 for improved grazing management, and 147 megatons of CO2e year-1 for sown legumes in pasturelands.


Assuntos
Sequestro de Carbono , Pradaria , Solo , Biomassa , Carbono/metabolismo , Plantas/metabolismo
19.
Environ Sci Technol ; 56(17): 11952-11968, 2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-35944157

RESUMO

Over the last millennia, wetlands have been sequestering carbon from the atmosphere via photosynthesis at a higher rate than releasing it and, therefore, have globally accumulated 550 × 1015 g of carbon, which is equivalent to 73% of the atmospheric carbon pool. The accumulation of organic carbon in wetlands is effectuated by phenolic compounds, which suppress the degradation of soil organic matter by inhibiting the activity of organic-matter-degrading enzymes. The enzymatic removal of phenolic compounds by bacterial tyrosinases has historically been blocked by anoxic conditions in wetland soils, resulting from waterlogging. Bacterial tyrosinases are a subgroup of oxidoreductases that oxidatively remove phenolic compounds, coupled to the reduction of molecular oxygen to water. The biochemical properties of bacterial tyrosinases have been investigated thoroughly in vitro within recent decades, while investigations focused on carbon fluxes in wetlands on a macroscopic level have remained a thriving yet separated research area so far. In the wake of climate change, however, anoxic conditions in wetland soils are threatened by reduced rainfall and prolonged summer drought. This potentially allows tyrosinase enzymes to reduce the concentration of phenolic compounds, which in turn will increase the release of stored carbon back into the atmosphere. To offer compelling evidence for the novel concept that bacterial tyrosinases are among the key enzymes influencing carbon cycling in wetland ecosystems first, bacterial organisms indigenous to wetland ecosystems that harbor a TYR gene within their respective genome (tyr+) have been identified, which revealed a phylogenetically diverse community of tyr+ bacteria indigenous to wetlands based on genomic sequencing data. Bacterial TYR host organisms covering seven phyla (Acidobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Nitrospirae, Planctomycetes, and Proteobacteria) have been identified within various wetland ecosystems (peatlands, marshes, mangrove forests, bogs, and alkaline soda lakes) which cover a climatic continuum ranging from high arctic to tropic ecosystems. Second, it is demonstrated that (in vitro) bacterial TYR activity is commonly observed at pH values characteristic for wetland ecosystems (ranging from pH 3.5 in peatlands and freshwater swamps to pH 9.0 in soda lakes and freshwater marshes) and toward phenolic compounds naturally present within wetland environments (p-coumaric acid, gallic acid, protocatechuic acid, p-hydroxybenzoic acid, caffeic acid, catechin, and epicatechin). Third, analyzing the available data confirmed that bacterial host organisms tend to exhibit in vitro growth optima at pH values similar to their respective wetland habitats. Based on these findings, it is concluded that, following increased aeration of previously anoxic wetland soils due to climate change, TYRs are among the enzymes capable of reducing the concentration of phenolic compounds present within wetland ecosystems, which will potentially destabilize vast amounts of carbon stored in these ecosystems. Finally, promising approaches to mitigate the detrimental effects of increased TYR activity in wetland ecosystems and the requirement of future investigations of the abundance and activity of TYRs in an environmental setting are presented.


Assuntos
Carbono , Áreas Alagadas , Bactérias/metabolismo , Carbono/metabolismo , Ecossistema , Monofenol Mono-Oxigenase , Solo/química
20.
J Cell Sci ; 135(17)2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35975718

RESUMO

In the yeast Saccharomyces cerevisiae, proteasomes are enriched in cell nuclei, in which they execute important cellular functions. Nutrient stress can change this localization, indicating that proteasomes respond to the metabolic state of the cell. However, the signals that connect these processes remain poorly understood. Carbon starvation triggers a reversible translocation of proteasomes to cytosolic condensates known as proteasome storage granules. Surprisingly, we observed strongly reduced levels of proteasome granules when cells had active cellular respiration prior to starvation. This suggests that the mitochondrial activity of cells is a determining factor in the response of proteasomes to carbon starvation. Consistent with this, upon inhibition of mitochondrial function, we observed that proteasomes relocalize to granules. These links between proteasomes and metabolism involve specific signaling pathways, as we identified a mitogen-activated protein kinase (MAPK) cascade that is critical to the formation of proteasome granules after respiratory growth but not following glycolytic growth. Furthermore, the yeast homolog of AMP kinase, Snf1, is important for proteasome granule formation induced by mitochondrial inhibitors, but it is dispensable for granule formation following carbon starvation. We propose a model in which mitochondrial activity promotes nuclear localization of the proteasome. This article has an associated First Person interview with the first author of the paper.


Assuntos
Complexo de Endopeptidases do Proteassoma , Saccharomyces cerevisiae , Carbono/metabolismo , Humanos , Mitocôndrias/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Respiração , Saccharomyces cerevisiae/metabolismo
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