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1.
Cell ; 187(7): 1801-1818.e20, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38471500

RESUMO

The repertoire of modifications to bile acids and related steroidal lipids by host and microbial metabolism remains incompletely characterized. To address this knowledge gap, we created a reusable resource of tandem mass spectrometry (MS/MS) spectra by filtering 1.2 billion publicly available MS/MS spectra for bile-acid-selective ion patterns. Thousands of modifications are distributed throughout animal and human bodies as well as microbial cultures. We employed this MS/MS library to identify polyamine bile amidates, prevalent in carnivores. They are present in humans, and their levels alter with a diet change from a Mediterranean to a typical American diet. This work highlights the existence of many more bile acid modifications than previously recognized and the value of leveraging public large-scale untargeted metabolomics data to discover metabolites. The availability of a modification-centric bile acid MS/MS library will inform future studies investigating bile acid roles in health and disease.


Assuntos
Ácidos e Sais Biliares , Microbioma Gastrointestinal , Metabolômica , Espectrometria de Massas em Tandem , Animais , Humanos , Ácidos e Sais Biliares/química , Metabolômica/métodos , Poliaminas , Espectrometria de Massas em Tandem/métodos , Bases de Dados de Compostos Químicos
2.
Protein Sci ; 33(4): e4937, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38501488

RESUMO

Cellulosomes are intricate cellulose-degrading multi-enzymatic complexes produced by anaerobic bacteria, which are valuable for bioenergy development and biotechnology. Cellulosome assembly relies on the selective interaction between cohesin modules in structural scaffolding proteins (scaffoldins) and dockerin modules in enzymes. Although the number of tandem cohesins in the scaffoldins is believed to determine the complexity of the cellulosomes, tandem dockerins also exist, albeit very rare, in some cellulosomal components whose assembly and functional roles are currently unclear. In this study, we characterized the structure and mode of assembly of a tandem bimodular double-dockerin, which is connected to a putative S8 protease in the cellulosome-producing bacterium, Clostridium thermocellum. Crystal and NMR structures of the double-dockerin revealed two typical type I dockerin folds with significant interactions between them. Interaction analysis by isothermal titration calorimetry and NMR titration experiments revealed that the double-dockerin displays a preference for binding to the cell-wall anchoring scaffoldin ScaD through the first dockerin with a canonical dual-binding mode, while the second dockerin module was unable to bind to any of the tested cohesins. Surprisingly, the double-dockerin showed a much higher affinity to a cohesin from the CipC scaffoldin of Clostridium cellulolyticum than to the resident cohesins from C. thermocellum. These results contribute valuable insights into the structure and assembly of the double-dockerin module, and provide the basis for further functional studies on multiple-dockerin modules and cellulosomal proteases, thus highlighting the complexity and diversity of cellulosomal components.


Assuntos
Clostridium thermocellum , 60634 , Clostridium thermocellum/química , Proteínas de Ciclo Celular/química , Proteínas Cromossômicas não Histona/química , Complexos Multienzimáticos , Proteínas de Bactérias/química
3.
Science ; 383(6688): eadj9223, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38484069

RESUMO

Humans, like all mammals, depend on the gut microbiome for digestion of cellulose, the main component of plant fiber. However, evidence for cellulose fermentation in the human gut is scarce. We have identified ruminococcal species in the gut microbiota of human populations that assemble functional multienzymatic cellulosome structures capable of degrading plant cell wall polysaccharides. One of these species, which is strongly associated with humans, likely originated in the ruminant gut and was subsequently transferred to the human gut, potentially during domestication where it underwent diversification and diet-related adaptation through the acquisition of genes from other gut microbes. Collectively, these species are abundant and widespread among ancient humans, hunter-gatherers, and rural populations but are rare in populations from industrialized societies thus indicating potential disappearance in response to the westernized lifestyle.


Assuntos
Celulose , Fibras na Dieta , Microbioma Gastrointestinal , Ruminococcus , Humanos , Celulose/metabolismo , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/fisiologia , Ruminococcus/classificação , Ruminococcus/enzimologia , Ruminococcus/genética , Fibras na Dieta/metabolismo , Filogenia , Desenvolvimento Industrial
4.
Nat Microbiol ; 9(1): 108-119, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38151647

RESUMO

Gut environments harbour dense microbial ecosystems in which plasmids are widely distributed. Plasmids facilitate the exchange of genetic material among microorganisms while enabling the transfer of a diverse array of accessory functions. However, their precise impact on microbial community composition and function remains largely unexplored. Here we identify a prevalent bacterial toxin and a plasmid-encoded resistance mechanism that mediates the interaction between Lactobacilli and Enterococci. This plasmid is widespread across ecosystems, including the rumen and human gut microbiota. Biochemical characterization of the plasmid revealed a defence mechanism against reuterin, a toxin produced by various gut microbes, such as Limosilactobacillus reuteri. Using a targeted metabolomic approach, we find reuterin to be prevalent across rumen ecosystems with impacts on microbial community structure. Enterococcus strains carrying the protective plasmid were isolated and their interactions with L. reuteri, the toxin producer, were studied in vitro. Interestingly, we found that by conferring resistance against reuterin, the plasmid mediates metabolic exchange between the defending and the attacking microbial species, resulting in a beneficial relationship or mutualism. Hence, we reveal here an ecological role for a plasmid-coded defence system in mediating a beneficial interaction.


Assuntos
Limosilactobacillus reuteri , Simbiose , Humanos , Animais , Ecossistema , Plasmídeos/genética , Propano/metabolismo , Limosilactobacillus reuteri/genética , Enterococcus/genética
5.
Methods Mol Biol ; 2657: 53-77, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37149522

RESUMO

Cellulosomes are multi-enzymatic nanomachines that have been fine-tuned through evolution to efficiently deconstruct plant biomass. Integration of cellulosomal components occurs via highly ordered protein-protein interactions between the various enzyme-borne dockerin modules and the multiple copies of the cohesin modules located on the scaffoldin subunit. Recently, designer cellulosome technology was established to provide insights into the architectural role of catalytic (enzymatic) and structural (scaffoldin) cellulosomal constituents for the efficient degradation of plant cell wall polysaccharides. Owing to advances in genomics and proteomics, highly structured cellulosome complexes have recently been unraveled, and the information gained has inspired the development of designer-cellulosome technology to new levels of complex organization. These higher-order designer cellulosomes have in turn fostered our capacity to enhance the catalytic potential of artificial cellulolytic complexes. In this chapter, methods to produce and employ such intricate cellulosomal complexes are reported.


Assuntos
Celulose , Celulossomas , Celulose/metabolismo , Parede Celular/metabolismo , Membrana Celular/metabolismo , Genômica , Celulossomas/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Ciclo Celular/metabolismo
6.
Microlife ; 4: uqad010, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37223726

RESUMO

Microbial taxonomy is critical for describing ecosystem composition, yet the link between taxonomy and properties of microbes, such as their cellular architecture, remains poorly defined. We hypothesized that the cellular architecture represents microbial niche adaptation. We used cryo-electron microscopy and tomography to analyze microbial morphology in order to associate cellular architecture with phylogeny and genomic contents. As a model system, we chose the core rumen microbiome and imaged a large isolate collection covering 90% of its richness at the order level. Based on quantifications of several morphological features, we found that the visual similarity of microbiota is significantly related to their phylogenetic distance. Up to the Family level, closely related microbes have similar cellular architectures, which are highly correlated with genome similarity. However, in more distantly related bacteria, the correlation both with taxonomy and genome similarity is lost. This is the first comprehensive study of microbial cellular architecture and our results highlight that structure remains an important parameter in classification of microorganisms, along with functional parameters such as metabolomics. Furthermore, the high-quality images presented in this study represent a reference database for the identification of bacteria in anaerobic ecosystems.

7.
Licere (Online) ; 26(1): 41-61, abril2023. tab, ilus
Artigo em Português | LILACS | ID: biblio-1436700

RESUMO

A crescente inserção dos profissionais de Educação Física no lazer reafirma as inúmeras possibilidades no mercado de trabalho, e a necessidade de uma formação que atenda a essas aspirações. Diante disso, a proposta investigada visa compreender como o lazer é tratado nos currículos dos cursos de Educação Física no sertão da Paraíba. Realizada a partir de buscas no e-Mec e plataformas digitais das instituições encontradas, a pesquisa se caracteriza como qualitativa e documental, sendo estabelecido as nomenclaturas "lazer" e "recreação" para a busca de conteúdos e disciplinas que contemplam a temática. No término do processo, foram encontradas treze instituições dispostas em nove cidades do sertão paraibano que certificam o caráter introdutório do lazer nos currículos de formação inicial, na oferta de poucas disciplinas e baixa carga horária.


The increasing insertion of Physical Education professionals in leisure reaffirms the numerous possibilities in the labor market, and the need for an education that meets these aspirations. Therefore, the investigated proposal aims to understand how leisure is dealt with in the curricula of Physical Education courses in the sertão of Paraíba. Conducted from searches in e-Mec and digital platforms of the institutions found, the research is characterized as qualitative and documentary, being established the nomenclatures "leisure" and "recreation" for the search for content and subjects that contemplate the theme. At the end of the process, thirteen institutions in nine cities in the sertão of Paraiba were found that certify the introductory nature of leisure in the initial training curricula, offering few subjects and low workload.


Assuntos
Mudança Social , Ensino
8.
ISME J ; 16(11): 2610-2621, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35974086

RESUMO

The arsenal of genes that microbes express reflect the way in which they sense their environment. We have previously reported that the rumen microbiome composition and its coding capacity are different in animals having distinct feed efficiency states, even when fed an identical diet. Here, we reveal that many microbial populations belonging to the bacteria and archaea domains show divergent proteome production in function of the feed efficiency state. Thus, proteomic data serve as a strong indicator of host feed efficiency state phenotype, overpowering predictions based on genomic and taxonomic information. We highlight protein production of specific phylogenies associated with each of the feed efficiency states. We also find remarkable plasticity of the proteome both in the individual population and at the community level, driven by niche partitioning and competition. These mechanisms result in protein production patterns that exhibit functional redundancy and checkerboard distribution that are tightly linked to the host feed efficiency phenotype. By linking microbial protein production and the ecological mechanisms that act within the microbiome feed efficiency states, our present work reveals a layer of complexity that bears immense importance to the current global challenges of food security and sustainability.


Assuntos
Microbiota , Rúmen , Ração Animal/análise , Animais , Fenótipo , Proteoma/genética , Proteoma/metabolismo , Proteômica , Rúmen/microbiologia
9.
Biotechnol Biofuels Bioprod ; 15(1): 68, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35725490

RESUMO

BACKGROUND: Natural cellulosome multi-enzyme complexes, their components, and engineered 'designer cellulosomes' (DCs) promise an efficient means of breaking down cellulosic substrates into valuable biofuel products. Their broad uptake in biotechnology relies on boosting proximity-based synergy among the resident enzymes, but the modular architecture challenges structure determination and rational design. RESULTS: We used small angle X-ray scattering combined with molecular modeling to study the solution structure of cellulosomal components. These include three dockerin-bearing cellulases with distinct substrate specificities, original scaffoldins from the human gut bacterium Ruminococcus champanellensis (ScaA, ScaH and ScaK) and a trivalent cohesin-bearing designer scaffoldin (Scaf20L), followed by cellulosomal complexes comprising these components, and the nonavalent fully loaded Clostridium thermocellum CipA in complex with Cel8A from the same bacterium. The size analysis of Rg and Dmax values deduced from the scattering curves and corresponding molecular models highlight their variable aspects, depending on composition, size and spatial organization of the objects in solution. CONCLUSIONS: Our data quantifies variability of form and compactness of cellulosomal components in solution and confirms that this native plasticity may well be related to speciation with respect to the substrate that is targeted. By showing that scaffoldins or components display enhanced compactness compared to the free objects, we provide new routes to rationally enhance their stability and performance in their environment of action.

10.
Biotechnol Biofuels Bioprod ; 15(1): 60, 2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35637485

RESUMO

BACKGROUND: Designer cellulosomes are self-assembled chimeric enzyme complexes that can be used to improve lignocellulosic biomass degradation. They are composed of a synthetic multimodular backbone protein, termed the scaffoldin, and a range of different chimeric docking enzymes that degrade polysaccharides. Over the years, several functional designer cellulosomes have been constructed. Since many parameters influence the efficiency of these multi-enzyme complexes, there is a need to optimise designer cellulosome architecture by testing combinatorial arrangements of docking enzyme and scaffoldin variants. However, the modular cloning procedures are tedious and cumbersome. RESULTS: VersaTile is a combinatorial DNA assembly method, allowing the rapid construction and thus comparison of a range of modular proteins. Here, we present the extension of the VersaTile platform to facilitate the construction of designer cellulosomes. We have constructed a tile repository, composed of dockerins, cohesins, linkers, tags and enzymatically active modules. The developed toolbox allows us to efficiently create and optimise designer cellulosomes at an unprecedented speed. As a proof of concept, a trivalent designer cellulosome able to degrade the specific hemicellulose substrate, galactomannan, was constructed and optimised. The main factors influencing cellulosome efficiency were found to be the selected dockerins and linkers and the docking enzyme ratio on the scaffoldin. The optimised designer cellulosome was able to hydrolyse the galactomannan polysaccharide and release mannose and galactose monomers. CONCLUSION: We have eliminated one of the main technical hurdles in the designer cellulosome field and anticipate the VersaTile platform to be a starting point in the development of more elaborate multi-enzyme complexes.

11.
Elife ; 112022 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-35638899

RESUMO

The lives of microbes unfold at the micron scale, and their molecular machineries operate at the nanoscale. Their study at these resolutions is key toward achieving a better understanding of their ecology. We focus on cellulose degradation of the canonical Clostridium thermocellum system to comprehend how microbes build and use their cellulosomal machinery at these nanometer scales. Degradation of cellulose, the most abundant organic polymer on Earth, is instrumental to the global carbon cycle. We reveal that bacterial cells form 'cellulosome capsules' driven by catalytic product-dependent dynamics, which can increase the rate of hydrolysis. Biosynthesis of this energetically costly machinery and cell growth are decoupled at the single-cell level, hinting at a division-of-labor strategy through phenotypic heterogeneity. This novel observation highlights intrapopulation interactions as key to understanding rates of fiber degradation.


Assuntos
Celulossomas , Clostridium thermocellum , Proteínas de Bactérias/metabolismo , Metabolismo dos Carboidratos , Celulose/metabolismo , Celulossomas/metabolismo , Fibras na Dieta/metabolismo , Hidrólise
12.
J Biol Chem ; 298(5): 101896, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35378131

RESUMO

Ruminococcus bromii is a keystone species in the human gut that has the rare ability to degrade dietary resistant starch (RS). This bacterium secretes a suite of starch-active proteins that work together within larger complexes called amylosomes that allow R. bromii to bind and degrade RS. Starch adherence system protein 20 (Sas20) is one of the more abundant proteins assembled within amylosomes, but little could be predicted about its molecular features based on amino acid sequence. Here, we performed a structure-function analysis of Sas20 and determined that it features two discrete starch-binding domains separated by a flexible linker. We show that Sas20 domain 1 contains an N-terminal ß-sandwich followed by a cluster of α-helices, and the nonreducing end of maltooligosaccharides can be captured between these structural features. Furthermore, the crystal structure of a close homolog of Sas20 domain 2 revealed a unique bilobed starch-binding groove that targets the helical α1,4-linked glycan chains found in amorphous regions of amylopectin and crystalline regions of amylose. Affinity PAGE and isothermal titration calorimetry demonstrated that both domains bind maltoheptaose and soluble starch with relatively high affinity (Kd ≤ 20 µM) but exhibit limited or no binding to cyclodextrins. Finally, small-angle X-ray scattering analysis of the individual and combined domains support that these structures are highly flexible, which may allow the protein to adopt conformations that enhance its starch-targeting efficiency. Taken together, we conclude that Sas20 binds distinct features within the starch granule, facilitating the ability of R. bromii to hydrolyze dietary RS.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Transporte , Ruminococcus , Amilopectina/metabolismo , Amilose/metabolismo , Proteínas de Transporte/metabolismo , Carboidratos da Dieta , Humanos , Amido/metabolismo
13.
Annu Rev Anim Biosci ; 10: 177-201, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34941382

RESUMO

Animal microbiomes are occasionally considered as an extension of host anatomy, physiology, and even their genomic architecture. Their compositions encompass variable and constant portions when examined across multiple hosts. The latter, termed the core microbiome, is viewed as more accommodated to its host environment and suggested to benefit host fitness. Nevertheless, discrepancies in its definitions, characteristics, and importance to its hosts exist across studies. We survey studies that characterize the core microbiome, detail its current definitions and available methods to identify it, and emphasize the crucial need to upgrade and standardize the methodologies among studies. We highlight ruminants as a case study and discussthe link between the core microbiome and host physiology and genetics, as well as potential factors that shape it. We conclude with main directives of action to better understand the host-core microbiome axis and acquire the necessary insights into its controlled modulation.


Assuntos
Microbioma Gastrointestinal , Microbiota , Animais , Crescimento e Desenvolvimento , Microbiota/genética
14.
J Struct Biol ; 213(3): 107765, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34186214

RESUMO

Pullulanases are glycoside hydrolase family 13 (GH13) enzymes that target α1,6 glucosidic linkages within starch and aid in the degradation of the α1,4- and α1,6- linked glucans pullulan, glycogen and amylopectin. The human gut bacterium Ruminococcus bromii synthesizes two extracellular pullulanases, Amy10 and Amy12, that are incorporated into the multiprotein amylosome complex that enables the digestion of granular resistant starch from the diet. Here we provide a comparative biochemical analysis of these pullulanases and the x-ray crystal structures of the wild type and the nucleophile mutant D392A of Amy12 complexed with maltoheptaose and 63-α-D glucosyl-maltotriose. While Amy10 displays higher catalytic efficiency on pullulan and cleaves only α1,6 linkages, Amy12 has some activity on α1,4 linkages suggesting that these enzymes are not redundant within the amylosome. Our structures of Amy12 include a mucin-binding protein (MucBP) domain that follows the C-domain of the GH13 fold, an atypical feature of these enzymes. The wild type Amy12 structure with maltoheptaose captured two oligosaccharides in the active site arranged as expected following catalysis of an α1,6 branch point in amylopectin. The nucleophile mutant D392A complexed with maltoheptaose or 63-α-D glucosyl-maltotriose captured ß-glucose at the reducing end in the -1 subsite, facilitated by the truncation of the active site aspartate and stabilized by stacking with Y279. The core interface between the co-crystallized ligands and Amy12 occurs within the -2 through + 1 subsites, which may allow for flexible recognition of α1,6 linkages within a variety of starch structures.


Assuntos
Glicosídeo Hidrolases , Ruminococcus , Glicosídeo Hidrolases/química , Humanos , Ruminococcus/genética , Ruminococcus/metabolismo , Amido/metabolismo , Especificidade por Substrato
15.
Nat Rev Microbiol ; 19(9): 553-566, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33981031

RESUMO

Ruminants produce edible products and contribute to food security. They house a complex rumen microbial community that enables the host to digest their plant feed through microbial-mediated fermentation. However, the rumen microbiome is also responsible for the production of one of the most potent greenhouse gases, methane, and contributes about 18% of its total anthropogenic emissions. Conventional methods to lower methane production by ruminants have proved successful, but to a limited and often temporary extent. An increased understanding of the host-microbiome interactions has led to the development of new mitigation strategies. In this Review we describe the composition, ecology and metabolism of the rumen microbiome, and the impact on host physiology and the environment. We also discuss the most pertinent methane mitigation strategies that emerged to balance food security and environmental impacts.


Assuntos
Bactérias/classificação , Meio Ambiente , Segurança Alimentar , Microbioma Gastrointestinal/fisiologia , Rúmen/microbiologia , Ruminantes/microbiologia , Animais , Bactérias/metabolismo , Ruminantes/fisiologia
16.
Microb Biotechnol ; 13(6): 1748-1764, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32639625

RESUMO

The multi-enzyme cellulosome complex can mediate the valorization of lignocellulosic biomass into soluble sugars that can serve in the production of biofuels and valuable products. A potent bacterial chassis for the production of active cellulosomes displayed on the cell surface is the bacterium Lactobacillus plantarum, a lactic acid bacterium used in many applications. Here, we developed a methodological pipeline to produce improved designer cellulosomes, using a cell-consortium approach, whereby the different components self-assemble on the surface of L. plantarum. The pipeline served as a vehicle to select and optimize the secretion efficiency of potent designer cellulosome enzyme components, to screen for the most efficient enzymatic combinations and to assess attempts to grow the engineered bacterial cells on wheat straw as a sole carbon source. Using this strategy, we were able to improve the secretion efficiency of the selected enzymes and to secrete a fully functional high-molecular-weight scaffoldin component. The adaptive laboratory process served to increase significantly the enzymatic activity of the most efficient cell consortium. Internal plasmid re-arrangement towards a higher enzymatic performance attested for the suitability of the approach, which suggests that this strategy represents an efficient way for microbes to adapt to changing conditions.


Assuntos
Celulossomas , Lactobacillus plantarum , Celulose , Plasmídeos , Triticum
17.
Biomater Sci ; 8(13): 3601-3610, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32232253

RESUMO

Lignocellulose is the most abundant renewable carbon source in the biosphere. However, the main bottleneck in its conversion to produce second generation biofuels is the saccharification step: the hydrolysis of lignocellulosic material into soluble fermentable sugars. Some anaerobic bacteria have developed an extracellular multi-enzyme complex called the cellulosome that efficiently degrades cellulosic substrates. Cellulosome complexes rely on enzyme-integrating scaffoldins that are large non-catalytic scaffolding proteins comprising several cohesin modules and additional functional modules that mediate the anchoring of the complex to the cell surface and the specific binding to its cellulosic substrate. It was proposed that mechanical forces may affect the cohesins positioned between the cell- and cellulose-anchoring points in the so-called connecting region. Consequently, the mechanical resistance of cohesins within the scaffoldin is of great importance, both to understand cellulosome function and as a parameter of industrial interest, to better mimic natural complexes through the use of the established designer cellulosome technology. Here we study how the mechanical stability of cohesins in a scaffoldin affects the enzymatic activity of a cellulosome. We found that when a cohesin of low mechanical stability is positioned in the connecting region of a scaffoldin, the activity of the resulting cellulosome is reduced as opposed to a cohesin of higher mechanical stability. This observation directly relates mechanical stability of the scaffoldin-borne cohesins to cellulosome activity and provides a rationale for the design of artificial cellulosomes for industrial applications, by incorporating mechanical stability as a new industrial parameter in the biotechnology toolbox.


Assuntos
Materiais Biocompatíveis/metabolismo , Celulossomas/metabolismo , Materiais Biocompatíveis/química , Celulossomas/química , Clostridium thermocellum/química , Clostridium thermocellum/metabolismo , Estresse Mecânico
18.
mBio ; 11(2)2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32234813

RESUMO

Clostridium saccharoperbutylacetonicum is a mesophilic, anaerobic, butanol-producing bacterium, originally isolated from soil. It was recently reported that C. saccharoperbutylacetonicum possesses multiple cellulosomal elements and would potentially form the smallest cellulosome known in nature. Its genome contains only eight dockerin-bearing enzymes, and its unique scaffoldin bears two cohesins (Cohs), three X2 modules, and two carbohydrate-binding modules (CBMs). In this study, all of the cellulosome-related modules were cloned, expressed, and purified. The recombinant cohesins, dockerins, and CBMs were tested for binding activity using enzyme-linked immunosorbent assay (ELISA)-based techniques. All the enzymes were tested for their comparative enzymatic activity on seven different cellulosic and hemicellulosic substrates, thus revealing four cellulases, a xylanase, a mannanase, a xyloglucanase, and a lichenase. All dockerin-containing enzymes interacted similarly with the second cohesin (Coh2) module, whereas Coh1 was more restricted in its interaction pattern. In addition, the polysaccharide-binding properties of the CBMs within the scaffoldin were examined by two complementary assays, affinity electrophoresis and affinity pulldown. The scaffoldin of C. saccharoperbutylacetonicum exhibited high affinity for cellulosic and hemicellulosic substrates, specifically to microcrystalline cellulose and xyloglucan. Evidence that supports substrate-dependent in vivo secretion of cellulosomes is presented. The results of our analyses contribute to a better understanding of simple cellulosome systems by identifying the key players in this minimalistic system and the binding pattern of its cohesin-dockerin interaction. The knowledge gained by our study will assist further exploration of similar minimalistic cellulosomes and will contribute to the significance of specific sets of defined cellulosomal enzymes in the degradation of cellulosic biomass.IMPORTANCE Cellulosome-producing bacteria are considered among the most important bacteria in both mesophilic and thermophilic environments, owing to their capacity to deconstruct recalcitrant plant-derived polysaccharides (and notably cellulose) into soluble saccharides for subsequent processing. In many ecosystems, the cellulosome-producing bacteria are particularly effective "first responders." The massive amounts of sugars produced are potentially amenable in industrial settings to further fermentation by appropriate microbes to biofuels, notably ethanol and butanol. Among the solvent-producing bacteria, Clostridium saccharoperbutylacetonicum has the smallest cellulosome system known thus far. The importance of investigating the building blocks of such a small, multifunctional nanomachine is crucial to understanding the fundamental activities of this efficient enzymatic complex.


Assuntos
Butanóis/metabolismo , Celulossomas/metabolismo , Clostridium/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/química , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Clostridium/genética , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Família Multigênica
19.
FEBS J ; 287(20): 4370-4388, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32064769

RESUMO

Biomass deconstruction remains integral for enabling second-generation biofuel production at scale. However, several steps necessary to achieve significant solubilization of biomass, notably harsh pretreatment conditions, impose economic barriers to commercialization. By employing hyperthermostable cellulase machinery, biomass deconstruction can be made more efficient, leading to milder pretreatment conditions and ultimately lower production costs. The hyperthermophilic bacterium Caldicellulosiruptor bescii produces extremely active hyperthermostable cellulases, including the hyperactive multifunctional cellulase CbCel9A/Cel48A. Recombinant CbCel9A/Cel48A components have been previously produced in Escherichia coli and integrated into synthetic hyperthermophilic designer cellulosome complexes. Since then, glycosylation has been shown to be vital for the high activity and stability of CbCel9A/Cel48A. Here, we studied the impact of glycosylation on a hyperthermostable designer cellulosome system in which two of the cellulosomal components, the scaffoldin and the GH9 domain of CbCel9A/Cel48A, were glycosylated as a consequence of employing Ca. bescii as an expression host. Inclusion of the glycosylated components yielded an active cellulosome system that exhibited long-term stability at 75 °C. The resulting glycosylated designer cellulosomes showed significantly greater synergistic activity compared to the enzymatic components alone, as well as higher thermostability than the analogous nonglycosylated designer cellulosomes. These results indicate that glycosylation can be used as an essential engineering tool to improve the properties of designer cellulosomes. Additionally, Ca. bescii was shown to be an attractive candidate for production of glycosylated designer cellulosome components, which may further promote the viability of this bacterium both as a cellulase expression host and as a potential consolidated bioprocessing platform organism.


Assuntos
Caldicellulosiruptor/metabolismo , Celulases/metabolismo , Celulose/metabolismo , Celulossomas/metabolismo , Temperatura , Glicosilação , Hidrólise
20.
Rev. iberoam. micol ; 36(4): 192-199, oct.-dic. 2019. ilus, tab, graf
Artigo em Inglês | IBECS | ID: ibc-191415

RESUMO

Background: Candida albicans is the main agent that causes vulvovaginal candidiasis. Resistance among isolates to azole antifungal agents has been reported. Aims: Due to the well-known antifungal potential of curcumin, the purpose of this work was to evaluate the in vitro anticandidal activity of curcumin and its effect in the treatment of experimental vulvovaginal candidiasis. Methods: The anticandidal activity of curcumin was investigated against eight Candida strains by the broth microdilution assay, and its mechanism of action was evaluated by testing the binding to ergosterol. Then, the effect of curcumin in the treatment of vulvovaginal candidiasis was evaluated in an immunosuppressed, estrogen treated rat model. Results: Curcumin showed minimum inhibitory concentration values of 125-1000μg/ml, and the best result was observed against Candida glabrata. The compound was shown to be able to bind to the ergosterol present in the membrane, event that may be the mechanism of action. In addition, in the in vivo model of vulvovaginal candidiasis with C. albicans, treatments reduced the vaginal fungal burden in infected rats after seven days of treatment with different doses. Conclusions: Curcumin could be considered a promising effective antifungal agent in the treatment of vulvovaginal candidiasis


Antecedentes: Candida albicans es la principal causante de la candidiasis vulvovaginal y algunos aislamientos pueden presentar resistencia a los antifúngicos azólicos. Objetivos: Debido al conocido potencial antifúngico de la curcumina, el objetivo de este trabajo fue evaluar su actividad anti-Candidain vitro y su efecto en el tratamiento de la candidiasis vulvovaginal experimental. Métodos: La actividad anti-Candida de la curcumina se evaluó frente a ocho cepas de Candida mediante un ensayo de microdilución en caldo, y su mecanismo de acción se estudió por una prueba de unión a ergosterol. Posteriormente se evaluó el efecto de la curcumina en el tratamiento de la candidiasis vulvovaginal con un modelo de rata inmunosuprimida, tratada con estrógenos. Resultados: La curcumina mostró valores de concentración inhibitoria mínima de 125-1.000μg/ml, y el mejor resultado se observó frente a Candida glabrata. El compuesto demostró ser capaz de unirse al ergosterol de la membrana, lo que podría ser su mecanismo de acción. Además, en el modelo in vivo de candidiasis vulvovaginal con C. albicans, los tratamientos redujeron la carga fúngica vaginal en ratas infectadas después de siete días de tratamiento con diferentes dosis. Conclusiones: La curcumina podría considerarse un agente antifúngico eficaz prometedor en el tratamiento de la candidiasis vulvovaginal


Assuntos
Humanos , Candida albicans/efeitos dos fármacos , Candidíase Vulvovaginal/tratamento farmacológico , Curcumina/farmacocinética , Técnicas In Vitro/métodos , Candida albicans/isolamento & purificação , Farmacorresistência Fúngica , Azóis/farmacocinética , Ergosterol/farmacocinética , Testes de Sensibilidade Microbiana/métodos
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