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1.
Commun Chem ; 7(1): 33, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38361005

RESUMO

The transition from inorganic catalysis through minerals to organic catalysis by enzymes is a necessary step in the emergence of life. Our work is elucidating likely reactions at the earliest moments of Life, prior to the existence of enzymatic catalysis, by exploring essential intersections between nickel bioinorganic chemistry and pterin biochemistry. We used a prebiotically-inspired acetylene-containing volcanic hydrothermal experimental environment to shed light on the efficient formation of nickel-organo complexes. The simplest bis(dithiolene)nickel complex (C2H2S2)2Ni was identified by UV/Vis spectroscopy, mass spectrometry, nuclear magnetic resonance. Its temporal progression and possible function in this simulated early Earth atmosphere were investigated by isolating the main bis(dithiolene)nickel species from the primordial experimental setup. Using this approach, we uncovered a significant diversity of nickel-organo compositions by identifying 156 elemental annotations. The formation of acetaldehyde through the subsequent degradation of these organo-metal complexes is intriguing, as it is reminiscent of the ability of Pelobacter acetylenicus to hydrate acetylene to acetaldehyde via its bis(dithiolene)-containing enzyme acetylene hydratase. As our findings mechanistically characterize the role of nickel sulfide in catalyzing the formation of acetaldehyde, this fundamental pre-metabolic reaction could play the role of a primitive enzyme precursor of the enzymatic acetylene metabolism and further strengthen the role of acetylene in the molecular origin of life.

2.
Commun Chem ; 6(1): 220, 2023 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-37828122

RESUMO

Chemical complexity is vital not only for the origin of life but also for biological evolution. The chemical evolution of a complex prebiotic mixture containing acetylene, carbon monoxide (CO), and nickel sulfide (NiS) has been analyzed with mass spectrometry as an untargeted approach to reaction monitoring. Here we show through isotopic 13C-labelling, multiple reaction products, encompassing diverse CHO and CHOS compounds within the complex reaction mixture. Molecules within the same chemical spaces displayed varying degrees of 13C-labelling, enabling more robust functional group characterization based on targeted investigations and differences in saturation levels among the described classes. A characteristic C2-addition pattern was detected in all compound classes in conjunction with a high diversity of thio acids, reminiscent of extant microbial C2-metabolism. The analysis involved a time-resolved molecular network, which unveiled the behavior of sulfur in the system. At the onset of the reaction, early formed compounds contain more sulfur atoms compared to later emerging compounds. These results give an essential insight into the still elusive role of sulfur dynamics in the origin of life. Moreover, our results provide temporally resolved evidence of the progressively increasing molecular complexity arising from a limited number of compounds.

3.
Sci Rep ; 13(1): 15227, 2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37710028

RESUMO

Microscopic compartmentalization is beneficial in synthetic chemistry and indispensable for the evolution of life to separate a reactive "inside" from a hydrolyzing "outside". Here, we show compartmentalization in aqueous solution containing mixtures of fatty acids up to 19 carbon atoms which were synthesized by one-pot reactions of acetylene and carbon monoxide in contact with nickel sulfide at 105 °C, reaction requirements which are compatible to Hadean Early Earth conditions. Based on confocal, dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements, vesicle-like structures with diameters of 10-150 nm are formed after solvent extraction and resolubilisation. Moreover fluorescent dye was encapsulated into the structures proving their vesicular properties. This self-assembly could also have occurred on Early Earth as a crucial step in establishing simple membranes of proto-cells as a prerequisite in the evolution of metabolism and life.

4.
EMBO J ; 42(19): e114162, 2023 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-37641864

RESUMO

Within the virion, adenovirus DNA associates with the virus-encoded, protamine-like structural protein pVII. Whether this association is organized, and how genome packaging changes during infection and subsequent transcriptional activation is currently unclear. Here, we combined RNA-seq, MNase-seq, ChIP-seq, and single genome imaging during early adenovirus infection to unveil the structure- and time-resolved dynamics of viral chromatin changes as well as their correlation with gene transcription. Our MNase mapping data indicates that the adenoviral genome is arranged in precisely positioned nucleoprotein particles with nucleosome-like characteristics, that we term adenosomes. We identified 238 adenosomes that are positioned by a DNA sequence code and protect about 60-70 bp of DNA. The incoming adenoviral genome is more accessible at early gene loci that undergo additional chromatin de-condensation upon infection. Histone H3.3 containing nucleosomes specifically replaces pVII at distinct genomic sites and at the transcription start sites of early genes. Acetylation of H3.3 is predominant at the transcription start sites and precedes transcriptional activation. Based on our results, we propose a central role for the viral pVII nucleoprotein architecture, which is required for the dynamic structural changes during early infection, including the regulation of nucleosome assembly prior to transcription initiation. Our study thus may aid the rational development of recombinant adenoviral vectors exhibiting sustained expression in gene therapy.


Assuntos
Cromatina , Nucleossomos , Nucleossomos/genética , Ativação Transcricional , Cromatina/genética , DNA/metabolismo , Montagem e Desmontagem da Cromatina , Adenoviridae/genética
5.
Commun Chem ; 6(1): 38, 2023 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-36813975

RESUMO

Many essential building blocks of life, including amino acids, sugars, and nucleosides, require aldehydes for prebiotic synthesis. Pathways for their formation under early earth conditions are therefore of great importance. We investigated the formation of aldehydes by an experimental simulation of primordial early earth conditions, in line with the metal-sulfur world theory in an acetylene-containing atmosphere. We describe a pH-driven, intrinsically autoregulatory environment that concentrates acetaldehyde and other higher molecular weight aldehydes. We demonstrate that acetaldehyde is rapidly formed from acetylene over a nickel sulfide catalyst in an aqueous solution, followed by sequential reactions progressively increasing the molecular diversity and complexity of the reaction mixture. Interestingly, through inherent pH changes, the evolution of this complex matrix leads to auto-stabilization of de novo synthesized aldehydes and alters the subsequent synthesis of relevant biomolecules rather than yielding uncontrolled polymerization products. Our results emphasize the impact of progressively generated compounds on the overall reaction conditions and strengthen the role of acetylene in forming essential building blocks that are fundamental for the emergence of terrestrial life.

6.
Vet Sci ; 10(1)2023 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-36669057

RESUMO

Chronic stress is recognized as a secret killer in poultry. It is associated with systemic inflammation due to cytokine release, dysbiosis, and the so-called leaky gut syndrome, which mainly results from oxidative stress reactions that damage the barrier function of the cells lining the gut wall. Poultry, especially the genetically selected broiler breeds, frequently suffer from these chronic stress symptoms when exposed to multiple stressors in their growing environments. Since oxidative stress reactions and inflammatory damages are multi-stage and long-term processes, overshooting immune reactions and their down-stream effects also negatively affect the animal's microbiota, and finally impair its performance and commercial value. Means to counteract oxidative stress in poultry and other animals are, therefore, highly welcome. Many phytogenic substances, including flavonoids and phenolic compounds, are known to exert anti-inflammatory and antioxidant effects. In this review, firstly, the main stressors in poultry, such as heat stress, mycotoxins, dysbiosis and diets that contain oxidized lipids that trigger oxidative stress and inflammation, are discussed, along with the key transcription factors involved in the related signal transduction pathways. Secondly, the most promising phytogenic substances and their current applications to ameliorate oxidative stress and inflammation in poultry are highlighted.

7.
Microb Cell Fact ; 21(1): 64, 2022 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-35440053

RESUMO

BACKGROUND: Terpene synthases are versatile catalysts in all domains of life, catalyzing the formation of an enormous variety of different terpenoid secondary metabolites. Due to their diverse bioactive properties, terpenoids are of great interest as innovative ingredients in pharmaceutical and cosmetic applications. Recent advances in genome sequencing have led to the discovery of numerous terpene synthases, in particular in Basidiomycota like the wood rotting fungus Coniophora puteana, which further enhances the scope for the manufacture of terpenes for industrial purposes. RESULTS: In this study we describe the identification of two novel (+)-δ-cadinol synthases from C. puteana, Copu5 and Copu9. The sesquiterpene (+)-δ-cadinol was previously shown to exhibit cytotoxic activity therefore having an application as possible, new, and sustainably sourced anti-tumor agent. In an Escherichia coli strain, optimized for sesquiterpene production, titers of 225 mg l-1 and 395 mg l-1, respectively, could be achieved. Remarkably, both enzymes share the same product profile thereby representing the first two terpene synthases from Basidiomycota with identical product profiles. We solved the crystal structure of Copu9 in its closed conformation, for the first time providing molecular details of sesquiterpene synthase from Basidiomycota. Based on the Copu9 structure, we conducted structure-based mutagenesis of amino acid residues lining the active site, thereby altering the product profile. Interestingly, the mutagenesis study also revealed that despite the conserved product profiles of Copu5 and Copu9 different conformational changes may accompany the catalytic cycle of the two enzymes. This observation suggests that the involvement of tertiary structure elements in the reaction mechanism(s) employed by terpene synthases may be more complex than commonly expected. CONCLUSION: The presented product selectivity and titers of Copu5 and Copu9 may pave the way towards a sustainable, biotechnological production of the potentially new bioactive (+)-δ-cadinol. Furthermore, Copu5 and Copu9 may serve as model systems for further mechanistic studies of terpenoid catalysis.


Assuntos
Alquil e Aril Transferases , Basidiomycota , Sesquiterpenos , Alquil e Aril Transferases/genética , Basidiomycota/metabolismo , Sesquiterpenos/metabolismo , Terpenos/metabolismo
8.
Microorganisms ; 10(2)2022 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-35208851

RESUMO

The gut microbiota has been designated as a hidden metabolic 'organ' because of its enormous impact on host metabolism, physiology, nutrition, and immune function. The connection between the intestinal microbiota and their respective host animals is dynamic and, in general, mutually beneficial. This complicated interaction is seen as a determinant of health and disease; thus, intestinal dysbiosis is linked with several metabolic diseases. Therefore, tractable strategies targeting the regulation of intestinal microbiota can control several diseases that are closely related to inflammatory and metabolic disorders. As a result, animal health and performance are improved. One of these strategies is related to dietary supplementation with prebiotics, probiotics, and phytogenic substances. These supplements exert their effects indirectly through manipulation of gut microbiota quality and improvement in intestinal epithelial barrier. Several phytogenic substances, such as berberine, resveratrol, curcumin, carvacrol, thymol, isoflavones and hydrolyzed fibers, have been identified as potential supplements that may also act as welcome means to reduce the usage of antibiotics in feedstock, including poultry farming, through manipulation of the gut microbiome. In addition, these compounds may improve the integrity of tight junctions by controlling tight junction-related proteins and inflammatory signaling pathways in the host animals. In this review, we discuss the role of probiotics, prebiotics, and phytogenic substances in optimizing gut function in poultry.

9.
Praxis (Bern 1994) ; 110(1): 3-4, 2022 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-34983202

RESUMO

Interprofessional Collaboration in Health Care Abstract. Interprofessional collaboration is a hallmark of good and efficient patient care, where several healthcare professionals put their competencies together to care for patients. Interprofessional education is a necessary first step to prepare the different professions for collaborations in their later professional practices. Shared training courses help to empower collaborative healthcare teams so they can respond in an adapted and effective way to individual and local health needs.


Assuntos
Relações Interprofissionais , Equipe de Assistência ao Paciente , Comportamento Cooperativo , Atenção à Saúde , Pessoal de Saúde , Humanos
10.
Artigo em Inglês | MEDLINE | ID: mdl-36992783

RESUMO

The integration of self-management education and support into the routine diabetes care is essential in preventing complications. Currently, however, there is no consensus on how to conceptualise integration in relation to self-management education and support. Therefore, this synthesis presents a framework conceptualising integration and self-management. Methods: Seven electronic databases (Medline, HMIC, PsycINFO, CINAHL, ERIC, Scopus and Web of Science) were searched. Twenty-one articles met the inclusion criteria. Data were synthesised using principles of critical interpretive synthesis to build the conceptual framework. The framework was presented to 49 diabetes specialist nurses working at different levels of care during a multilingual workshop. Results: A conceptual framework is proposed in which integration is influenced by five interacting components: the programme ethos of the diabetes self-management education and support intervention (content and delivery), care system organisation (the framework in which such interventions are delivered), adapting to context (the aspects of the people receiving and delivering the interventions), interpersonal relationship (the interactions between the deliverer and receiver of the intervention), and shared learning (what deliverer and receiver gain from the interactions). The critical inputs from the workshop participants related to the different priorities given to the components according to their sociolinguistic and educational experiences, Overall, they agreed with the conceptualisation of the components and their content specific to diabetes self-management education and support. Discussion: Integration was conceptualised in terms of the relational, ethical, learning, contextual adapting, and systemic organisational aspects of the intervention. It remains uncertain which prioritised interactions of components and to what extent these may moderate the integration of self-management education and support into routine care; in turn, the level of integration observed in each of the components may moderate the impact of these interventions, which may also apply to the impact of the professional training. Conclusion: This synthesis provides a theoretical framework that conceptualises integration in the context of diabetes self-management education and support in routine care. More research is required to evaluate how the components identified in the framework can be addressed in clinical practice to assess whether improvements in self-management education and support can be effectively realised in this population.

11.
ISME J ; 16(4): 1095-1109, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34857933

RESUMO

A key challenge in microbiome research is to predict the functionality of microbial communities based on community membership and (meta)-genomic data. As central microbiota functions are determined by bacterial community networks, it is important to gain insight into the principles that govern bacteria-bacteria interactions. Here, we focused on the growth and metabolic interactions of the Oligo-Mouse-Microbiota (OMM12) synthetic bacterial community, which is increasingly used as a model system in gut microbiome research. Using a bottom-up approach, we uncovered the directionality of strain-strain interactions in mono- and pairwise co-culture experiments as well as in community batch culture. Metabolic network reconstruction in combination with metabolomics analysis of bacterial culture supernatants provided insights into the metabolic potential and activity of the individual community members. Thereby, we could show that the OMM12 interaction network is shaped by both exploitative and interference competition in vitro in nutrient-rich culture media and demonstrate how community structure can be shifted by changing the nutritional environment. In particular, Enterococcus faecalis KB1 was identified as an important driver of community composition by affecting the abundance of several other consortium members in vitro. As a result, this study gives fundamental insight into key drivers and mechanistic basis of the OMM12 interaction network in vitro, which serves as a knowledge base for future mechanistic in vivo studies.


Assuntos
Microbioma Gastrointestinal , Microbiota , Animais , Bactérias/genética , Bactérias/metabolismo , Redes e Vias Metabólicas , Camundongos , Nutrientes
12.
Life (Basel) ; 11(9)2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34575129

RESUMO

Porphyrins, corrins, and tetrapyrroles constitute macrocycles in essential biomolecules such as heme, chlorophyll, cobalamin, and cofactor F430. The chemical synthesis as well as the enzymatic synthesis of these macrocycles starts from pyrrole derivatives. We here show that pyrrole and dimethyl pyrrole can be formed under the simulated volcanic, hydrothermal conditions of Early Earth, starting from acetylene, propyne, and ammonium salts in the presence of NiS or CoS as catalysts.

13.
Int J Med Microbiol ; 311(4): 151504, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33906075

RESUMO

The metabolism of Legionella pneumophila strain Paris was elucidated during different time intervals of growth within its natural host Acanthamoeba castellanii. For this purpose, the amoebae were supplied after bacterial infection (t =0 h) with 11 mM [U-13C6]glucose or 3 mM [U-13C3]serine, respectively, during 0-17 h, 17-25 h, or 25-27 h of incubation. At the end of these time intervals, bacterial and amoebal fractions were separated. Each of these fractions was hydrolyzed under acidic conditions. 13C-Enrichments and isotopologue distributions of resulting amino acids and 3-hydroxybutyrate were determined by gas chromatography - mass spectrometry. Comparative analysis of the labelling patterns revealed the substrate preferences, metabolic pathways, and relative carbon fluxes of the intracellular bacteria and their amoebal host during the time course of the infection cycle. Generally, the bacterial infection increased the usage of exogenous glucose via glycolysis by A. castellanii. In contrast, carbon fluxes via the amoebal citrate cycle were not affected. During the whole infection cycle, intracellular L. pneumophila incorporated amino acids from their host into the bacterial proteins. However, partial bacterial de novo biosynthesis from exogenous 13C-Ser and, at minor rates, from 13C-glucose could be shown for bacterial Ala, Asp, Glu, and Gly. More specifically, the catabolic usage of Ser increased during the post-exponential phase of intracellular growth, whereas glucose was utilized by the bacteria throughout the infection cycle and not only late during infection as assumed on the basis of earlier in vitro experiments. The early usage of 13C-glucose by the intracellular bacteria suggests that glucose availability could serve as a trigger for replication of L. pneumophila inside the vacuoles of host cells.


Assuntos
Acanthamoeba castellanii , Legionella pneumophila , Aminoácidos/metabolismo , Proteínas de Bactérias/metabolismo , Legionella pneumophila/metabolismo , Redes e Vias Metabólicas
14.
Life (Basel) ; 11(2)2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33669362

RESUMO

Thiophene was detected on Mars during the Curiosity mission in 2018. The compound was even suggested as a biomarker due to its possible origin from diagenesis or pyrolysis of biological material. In the laboratory, thiophene can be synthesized at 400 °C by reacting acetylene and hydrogen sulfide on alumina. We here show that thiophene and thiophene derivatives are also formed abiotically from acetylene and transition metal sulfides such as NiS, CoS and FeS under simulated volcanic, hydrothermal conditions on Early Earth. Exactly the same conditions were reported earlier to have yielded a plethora of organic molecules including fatty acids and other components of extant metabolism. It is therefore tempting to suggest that thiophenes from abiotic formation could indicate sites and conditions well-suited for the evolution of metabolism and potentially for the origin-of-life on extraterrestrial planets.

16.
Diabet Med ; 38(5): e14498, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33314244

RESUMO

AIM: To describe diabetes nurses' perspectives on the impact of the COVID-19 pandemic on people with diabetes and diabetes services across Europe. METHODS: An online survey developed using a rapid Delphi method. The survey was translated into 17 different languages and disseminated electronically in 27 countries via national diabetes nurse networks. RESULTS: Survey responses from 1829 diabetes nurses were included in the analysis. The responses indicated that 28% (n = 504) and 48% (n = 873) of diabetes nurses felt the COVID-19 pandemic had impacted 'a lot' on the physical and psychological risks of people with diabetes, respectively. The following clinical problems were identified as having increased 'a lot': anxiety 82% (n = 1486); diabetes distress 65% (n = 1189); depression 49% (n = 893); acute hyperglycaemia 39% (n = 710) and foot complications 18% (n = 323). Forty-seven percent (n = 771) of respondents identified that the level of care provided to people with diabetes had declined either extremely or quite severely. Self-management support, diabetes education and psychological support were rated by diabetes nurse respondents as having declined extremely or quite severely during the COVID-19 pandemic by 31% (n = 499), 63% (n = 1,027) and 34% (n = 551), respectively. CONCLUSION: The findings show that diabetes nurses across Europe have seen significant increases in both physical and psychological problems in their patient populations during COVID-19. The data also show that clinical diabetes services have been significantly disrupted. As the COVID-19 situation continues, we need to adapt care systems with some urgency to minimise the impact of the pandemic on the diabetes population.


Assuntos
COVID-19 , Atenção à Saúde , Diabetes Mellitus/fisiopatologia , Enfermeiras Especialistas , Angústia Psicológica , Ansiedade/psicologia , Atitude do Pessoal de Saúde , Depressão/psicologia , Diabetes Mellitus/metabolismo , Diabetes Mellitus/enfermagem , Diabetes Mellitus/psicologia , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/enfermagem , Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 1/psicologia , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/enfermagem , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Mellitus Tipo 2/psicologia , Pé Diabético/fisiopatologia , Europa (Continente) , Humanos , Hiperglicemia/metabolismo , SARS-CoV-2 , Autogestão , Inquéritos e Questionários
17.
Metabolites ; 10(9)2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32878015

RESUMO

The increasing global emergence of multidrug resistant (MDR) pathogens is categorized as one of the most important health problems. Therefore, the discovery of novel antimicrobials is of the utmost importance. Lichens provide a rich source of natural products including unique polyketides and polyphenols. Many of them display pharmaceutical benefits. The aim of this study was directed towards the characterization of sunflower oil extracts from the fruticose lichen, Usnea barbata. The concentration of the major polyketide, usnic acid, was 1.6 mg/mL extract as determined by NMR analysis of the crude mixture corresponding to 80 mg per g of the dried lichen. The total phenolics and flavonoids were determined by photometric assays as 4.4 mg/mL (gallic acid equivalent) and 0.27 mg/mL (rutin equivalent) corresponding to 220 mg/g and 13.7 mg/g lichen, respectively. Gram-positive (e.g., Enterococcus faecalis) and Gram-negative bacteria, as well as clinical isolates of infected chickens were sensitive against these extracts as determined by agar diffusion tests. Most of these activities increased in the presence of zinc salts. The data suggest the potential usage of U. barbata extracts as natural additives and mild antibiotics in animal husbandry, especially against enterococcosis in poultry.

18.
Nat Microbiol ; 5(11): 1390-1402, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32747796

RESUMO

Obligate intracellular bacteria such as Chlamydia trachomatis undergo a complex developmental cycle between infectious, non-replicative elementary-body and non-infectious, replicative reticulate-body forms. Elementary bodies transform to reticulate bodies shortly after entering a host cell, a crucial process in infection, initiating chlamydial replication. As Chlamydia fail to replicate outside the host cell, it is unknown how the replicative part of the developmental cycle is initiated. Here we show, using a cell-free approach in axenic media, that the uptake of glutamine by the bacteria is crucial for peptidoglycan synthesis, which has a role in Chlamydia replication. The increased requirement for glutamine in infected cells is satisfied by reprogramming the glutamine metabolism in a c-Myc-dependent manner. Glutamine is effectively taken up by the glutamine transporter SLC1A5 and metabolized via glutaminase. Interference with this metabolic reprogramming limits the growth of Chlamydia. Intriguingly, Chlamydia failed to produce progeny in SLC1A5-knockout organoids and mice. Thus, we report on the central role of glutamine for the development of an obligate intracellular pathogenic bacterium and the reprogramming of host glutamine metabolism, which may provide a basis for innovative anti-infection strategies.


Assuntos
Infecções por Chlamydia/metabolismo , Chlamydia trachomatis/fisiologia , Glutamina/metabolismo , Peptidoglicano/biossíntese , Sistema ASC de Transporte de Aminoácidos/genética , Sistema ASC de Transporte de Aminoácidos/metabolismo , Animais , Linhagem Celular , Infecções por Chlamydia/microbiologia , Chlamydia trachomatis/crescimento & desenvolvimento , Chlamydia trachomatis/metabolismo , Regulação da Expressão Gênica , Interações Hospedeiro-Patógeno , Humanos , Camundongos , Antígenos de Histocompatibilidade Menor/genética , Antígenos de Histocompatibilidade Menor/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transdução de Sinais
19.
FEMS Microbiol Ecol ; 96(6)2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358961

RESUMO

Virtually all heterotrophs incorporate carbon dioxide by anaplerotic fixation. Little explored, however, is the interdependency of pathways and rates of CO2fixation on the concurrent usage of organic substrate(s). Potentially, this could reveal which substrates out of a pool of dissolved organic carbon are utilised by environmental microorganisms. To explore this possibility, Bacillus subtilis W23 was grown in a minimal medium with normalised amounts of either glucose, lactate or malate as only organic substrates, each together with 1 g/L NaH13CO3. Incorporation of H13CO3- was traced by elemental analysis-isotope ratio mass spectrometry of biomass and gas chromatography-mass spectrometry of protein-derived amino acids. Until the late logarithmic phase, 13C incorporation into the tricarboxylic acid cycle increased with time and occurred via [4-13C]oxaloacetate formed by carboxylation of pyruvate. The levels of 13C incorporation were highest for growth on glucose and lowest on malate. Incorporation of 13C into gluconeogenesis products was mainly detected in the lactate and malate experiment, whereas glucose down-regulated this path. A proof-of-principle study with a natural groundwater community confirmed the ability to determine incorporation from H13CO3- by natural communities leading to specific labelling patterns. This underlines the potential of the labelling approach to characterise carbon sources of heterotrophic microorganisms in their natural environments.


Assuntos
Dióxido de Carbono , Gluconeogênese , Bactérias , Isótopos de Carbono , Marcação por Isótopo
20.
Life (Basel) ; 10(4)2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32272667

RESUMO

Carbon fixation, in addition to the evolution of metabolism, is a main requirement for the evolution of life. Here, we report a one-pot carbon fixation of acetylene (C2H2) and carbon monoxide (CO) by aqueous nickel sulfide (NiS) under hydrothermal (>100 °C) conditions. A slurry of precipitated NiS converts acetylene and carbon monoxide into a set of C2-4-products that are surprisingly representative for C2-4-segments of all four central CO2-fixation cycles of the domains Bacteria and Archaea, whereby some of the products engage in the same interconversions, as seen in the central CO2-fixation cycles. The results suggest a primordial, chemically predetermined, non-cyclic acetyleno/carboxydotrophic core metabolism. This metabolism is based on aqueous organo-metal chemistry, from which the extant central CO2-fixation cycles based on thioester chemistry would have evolved by piecemeal modifications.

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