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1.
Cells ; 9(9)2020 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-32899484

RESUMO

Hybrid nanoparticles from lipidic and polymeric components were assembled to serve as vehicles for the transfection of messenger RNA (mRNA) using different portions of the cationic lipid DOTAP (1,2-Dioleoyl-3-trimethylammonium-propane) and the cationic biopolymer protamine as model systems. Two different sequential assembly approaches in comparison with a direct single-step protocol were applied, and molecular organization in correlation with biological activity of the resulting nanoparticle systems was investigated. Differences in the structure of the nanoparticles were revealed by thorough physicochemical characterization including small angle neutron scattering (SANS), small angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM). All hybrid systems, combining lipid and polymer, displayed significantly increased transfection in comparison to lipid/mRNA and polymer/mRNA particles alone. For the hybrid nanoparticles, characteristic differences regarding the internal organization, release characteristics, and activity were determined depending on the assembly route. The systems with the highest transfection efficacy were characterized by a heterogenous internal organization, accompanied by facilitated release. Such a system could be best obtained by the single step protocol, starting with a lipid and polymer mixture for nanoparticle formation.


Assuntos
Biopolímeros/química , Lipídeos/química , Nanopartículas/química , RNA Mensageiro/metabolismo , Transfecção/métodos , Animais , Linhagem Celular , Ácidos Graxos Monoinsaturados/química , Feminino , Heparina/química , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Imagem Óptica , Tamanho da Partícula , Compostos de Amônio Quaternário/química , RNA Mensageiro/química
2.
Proc Natl Acad Sci U S A ; 117(28): 16160-16166, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601183

RESUMO

Biomolecules can undergo liquid-liquid phase separation (LLPS), forming dense droplets that are increasingly understood to be important for cellular function. Analogous systems are studied as early-life compartmentalization mechanisms, for applications as protocells, or as drug-delivery vehicles. In many of these situations, interactions between the droplet and enzymatic solutes are important to achieve certain functions. To explore this, we carried out experiments in which a model LLPS system, formed from DNA "nanostar" particles, interacted with a DNA-cleaving restriction enzyme, SmaI, whose activity degraded the droplets, causing them to shrink with time. By controlling adhesion of the DNA droplet to a glass surface, we were able to carry out time-resolved imaging of this "active dissolution" process. We found that the scaling properties of droplet shrinking were sensitive to the proximity to the dissolution ("boiling") temperature of the dense liquid: For systems far from the boiling point, enzymes acted only on the droplet surface, while systems poised near the boiling point permitted enzyme penetration. This was corroborated by the observation of enzyme-induced vacuole-formation ("bubbling") events, which can only occur through enzyme internalization, and which occurred only in systems poised near the boiling point. Overall, our results demonstrate a mechanism through which the phase stability of a liquid affects its enzymatic degradation through modulation of enzyme transport properties.


Assuntos
DNA/química , DNA/metabolismo , Biopolímeros/química , Biopolímeros/metabolismo , Enzimas de Restrição do DNA/metabolismo , Transição de Fase , Temperatura
3.
Int J Antimicrob Agents ; 56(2): 105998, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32360231

RESUMO

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic is a global public health emergency, and new therapeutics are needed. This article reports the potential drug target and mechanism of action of Arbidol (umifenovir) to treat coronavirus disease 2019 (COVID-19). Molecular dynamics and structural analysis were used to show how Arbidol targets the SARS-CoV-2 spike glycoprotein and impedes its trimerization, which is key for host cell adhesion and hijacking, indicating the potential of Arbidol to treat COVID-19. It is hoped that knowledge of the potential drug target and mechanism of action of Arbidol will help in the development of new therapeutics for SARS-CoV-2.


Assuntos
Antivirais/farmacologia , Betacoronavirus/efeitos dos fármacos , Biopolímeros/química , Infecções por Coronavirus/tratamento farmacológico , Indóis/farmacologia , Pneumonia Viral/tratamento farmacológico , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Antivirais/uso terapêutico , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/virologia , Humanos , Indóis/química , Pandemias , Pneumonia Viral/virologia
4.
Nat Commun ; 11(1): 2315, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385229

RESUMO

As established nearly a century ago, mechanoradicals originate from homolytic bond scission in polymers. The existence, nature and biological relevance of mechanoradicals in proteins, instead, are unknown. We here show that mechanical stress on collagen produces radicals and subsequently reactive oxygen species, essential biological signaling molecules. Electron-paramagnetic resonance (EPR) spectroscopy of stretched rat tail tendon, atomistic molecular dynamics simulations and quantum-chemical calculations show that the radicals form by bond scission in the direct vicinity of crosslinks in collagen. Radicals migrate to adjacent clusters of aromatic residues and stabilize on oxidized tyrosyl radicals, giving rise to a distinct EPR spectrum consistent with a stable dihydroxyphenylalanine (DOPA) radical. The protein mechanoradicals, as a yet undiscovered source of oxidative stress, finally convert into hydrogen peroxide. Our study suggests collagen I to have evolved as a radical sponge against mechano-oxidative damage and proposes a mechanism for exercise-induced oxidative stress and redox-mediated pathophysiological processes.


Assuntos
Colágeno/química , Tendões/química , Animais , Materiais Biocompatíveis/química , Biopolímeros/química , Di-Hidroxifenilalanina/química , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/química , Oxirredução , Estresse Oxidativo , Ratos , Espécies Reativas de Oxigênio/química
5.
Phys Chem Chem Phys ; 22(16): 8667-8671, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32270833

RESUMO

We study the relation between the macroscopic viscoelastic properties of aqueous hyaluronan polymer solutions and the molecular-scale dynamics of water using rheology measurements, differential dynamic microscopy, and polarization-resolved infrared pump-probe spectroscopy. We observe that the addition of hyaluronan to water leads to a slowing down of the reorientation of a fraction of the water molecules. Near pH 2.4, the viscosity of the hyaluronan solution reaches a maximum, while the number of slowed down water molecules reaches a minimum. This implies that the water molecules become on average more mobile when the solution becomes more viscous. This observation indicates that the increase in viscosity involves the expulsion of hydration water from the surfaces of the hyaluronan polymers, and a bundling of the hyaluronan polymer chains.


Assuntos
Biopolímeros/química , Géis/química , Ácido Hialurônico/química , Água/química , Concentração de Íons de Hidrogênio , Reologia , Espectrofotometria Infravermelho
6.
Phys Rev Lett ; 124(11): 118002, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32242707

RESUMO

Motivated by the dynamics of particles embedded in active gels, both in vitro and inside the cytoskeleton of living cells, we study an active generalization of the classical trap model. We demonstrate that activity leads to dramatic modifications in the diffusion compared to the thermal case: the mean square displacement becomes subdiffusive, spreading as a power law in time, when the trap depth distribution is a Gaussian and is slower than any power law when it is drawn from an exponential distribution. The results are derived for a simple, exactly solvable, case of harmonic traps. We then argue that the results are robust for more realistic trap shapes when the activity is strong.


Assuntos
Biopolímeros/química , Modelos Químicos , Citoesqueleto de Actina/química , Trifosfato de Adenosina/química , Difusão , Géis/química , Miosina Tipo II/química
7.
Nat Commun ; 11(1): 1561, 2020 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-32214099

RESUMO

Cells possess non-membrane-bound bodies, many of which are now understood as phase-separated condensates. One class of such condensates is composed of two polymer species, where each consists of repeated binding sites that interact in a one-to-one fashion with the binding sites of the other polymer. Biologically-motivated modeling revealed that phase separation is suppressed by a "magic-number effect" which occurs if the two polymers can form fully-bonded small oligomers by virtue of the number of binding sites in one polymer being an integer multiple of the number of binding sites of the other. Here we use lattice-model simulations and analytical calculations to show that this magic-number effect can be greatly enhanced if one of the polymer species has a rigid shape that allows for multiple distinct bonding conformations. Moreover, if one species is rigid, the effect is robust over a much greater range of relative concentrations of the two species.


Assuntos
Biopolímeros/química , Sítios de Ligação , Fenômenos Biofísicos , Biopolímeros/metabolismo , Modelos Moleculares , Conformação Molecular , Transição de Fase , Ligação Proteica
8.
J Chem Phys ; 152(4): 045102, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32007034

RESUMO

The physical chemistry of liquid-liquid phase separation (LLPS) of polymer solutions bears directly on the assembly of biologically functional dropletlike bodies from proteins and nucleic acids. These biomolecular condensates include certain extracellular materials and intracellular compartments that are characterized as "membraneless organelles." Analytical theories are a valuable, computationally efficient tool for addressing general principles. LLPS of neutral homopolymers is quite well described by theory, but it has been a challenge to develop general theories for the LLPS of heteropolymers involving charge-charge interactions. Here, we present a theory that combines a random-phase-approximation treatment of polymer density fluctuations and an account of intrachain conformational heterogeneity based on renormalized Kuhn lengths to provide predictions of LLPS properties as a function of pH, salt, and charge patterning along the chain sequence. Advancing beyond more limited analytical approaches, our LLPS theory is applicable to a wide variety of charged sequences ranging from highly charged polyelectrolytes to neutral or nearly neutral polyampholytes. This theory should be useful in high-throughput screening of protein and other sequences for their LLPS propensities and can serve as a basis for more comprehensive theories that incorporate nonelectrostatic interactions. Experimental ramifications of our theory are discussed.


Assuntos
Biopolímeros/química , Modelos Químicos , Polieletrólitos/química , Polímeros/química , Tampões (Química) , Ensaios de Triagem em Larga Escala , Extração Líquido-Líquido/métodos
9.
Appl Microbiol Biotechnol ; 104(7): 3121-3131, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32060693

RESUMO

Antibiotic resistance in pathogenic bacteria is a major health challenge, as Infectious Diseases Society of America (IDSA) has recognized that the past simply drugs susceptible pathogens are now the most dangerous pathogens due to their nonstop growing resistance towards conventional antibiotics. Therefore, due to the emergence of multi-drug resistance, the bacterial infections have become a serious global problem. Acute infections feasibly develop into chronic infections because of many factors; one of them is the failure of effectiveness of antibiotics against superbugs. Modern research of two-dimensional nanoparticles and biopolymers are of great interest to attain the intricate bactericidal activity. In this study, we fabricated an antibacterial nanocomposite consisting of representative two-dimensional molybdenum disulfide (2D MoS2) nanoparticles. Polyhydroxyalkanoate (PHA) and chitosan (Ch) are used to encapsulate MoS2 nanoparticles into their matrix. This study reports the in vitro antibacterial activity and host cytotoxicity of novel PHA-Ch/MoS2 nanocomposites. PHA-Ch/MoS2 nanocomposites were subjected to time-dependent antibacterial assays at various doses to examine their antibacterial activity against multi-drug-resistant Escherichia coli K1 (Malaysian Type Culture Collection 710859) and methicillin-resistant Staphylococcus aureus (MRSA) (Malaysian Type Culture Collection 381123). Furthermore, the cytotoxicity of nanocomposites was examined against spontaneously immortalized human keratinocyte (HaCaT) cell lines. The results indicated significant antibacterial activity (p value < 0.05) against E. coli K1 and MRSA. In addition, PHA-Ch/MoS2 showed significant host cytocompatibility (p < 0.05) against HaCaT cells. The fabricated PHA-Ch/MoS2 nanocomposites have demonstrated effective antibacterial activity against both Gram-positive and -negative bacteria and exhibited better biocompatibility. Finally, PHA-Ch/MoS2 nanocomposites are shown to be suitable for antibacterial applications and also hold potential for further biomedical studies. Graphical Abstract.


Assuntos
Antibacterianos/farmacologia , Biopolímeros/farmacologia , Dissulfetos/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Molibdênio/farmacologia , Poli-Hidroxialcanoatos/farmacologia , Antibacterianos/química , Biopolímeros/química , Linhagem Celular , Quitosana/química , Dissulfetos/química , Farmacorresistência Bacteriana Múltipla/fisiologia , Humanos , Nanopartículas Metálicas/química , Molibdênio/química , Nanocompostos/química , Poli-Hidroxialcanoatos/síntese química , Poli-Hidroxialcanoatos/química
10.
Carbohydr Polym ; 234: 115747, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32070497

RESUMO

Biopolymers as films are defined as materials prepared from biological molecules with filmogenic morphology that can be versatile uses. The present research aimed to study formulations of natural polymeric composites based on babassu coconut mesocarp (BCM), alginate and glycerol, to verify the effect of these components on moisture, solubility, thickness and water vapor permeability (WVP) parameters for different cross-linking stages. After a second cross-linking was applied, they presented lower thickness, solubility, and WVP values than first cross-linking. Consecutive analyses for selected film formulations showed that the formulation to solutions of 400 mL with 3g of BCM, 7.5g of alginate and 4.0g of glycerol had the most promising results when correlating physical parameters with thermal analyses, chemical and mechanical properties. Films with amount of babassu coconut mesocarp in the proportion established were sturdy to solubility, leaching and thermal degradation, improved by second cross-linking applied.


Assuntos
Alginatos/química , Biopolímeros/química , Cocos/química , Reagentes para Ligações Cruzadas/química , Glicerol/química , Permeabilidade , Solubilidade , Temperatura , Água/química
11.
J Colloid Interface Sci ; 565: 360-367, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31981845

RESUMO

In recent years, increasing environmental awareness and human skin protection from harmful radiation of the sun has attracted attention amongst numerous researchers. Here, a simple strategy was developed to enhance the hydrophilicity and ultraviolet (UV) protection of polyethylene terephthalate (PET) knitted fabric surface via grafting green cowpea protein (CP) with gum arabic modified epoxy (GAE) as a cross-linking agent. Chemical grafting between pretreated PET and GAE as well as between GAE and CP improved the hydrophilicity and UV protection of PET knitted Fabric. The enhanced surface wettability was confirmed by the decreased water contact angle from 135° to zero °. Moreover, the UV protection factor rating of modified PET knitted fabric was higher, indicating that the modifier layer caused scattering and absorbance of UV light. This approach has shown promising results for improving hydrophilicity and UV protection with sustained mechanical durability of 7 washing cycles.


Assuntos
Biopolímeros/química , Proteínas de Plantas/química , Polietilenotereftalatos/química , Raios Ultravioleta , Vigna/química , Tamanho da Partícula , Propriedades de Superfície , Molhabilidade
12.
J Sci Food Agric ; 100(6): 2337-2347, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31960453

RESUMO

Hydrogels are important materials that are of high scientific interest and with numerous applications. Natural polymer-based hydrogels are preferred to synthetic ones due to their safety, biocompatibility, and ecofriendly properties. They have been studied extensively and implemented in various fields, such as medicine, cosmetics, personal-care products, water purification, and more. This review focuses on the applications of nature-sourced polymer-based hydrogels in food and agriculture. Different types of biopolymers and crosslinking agents, and various methods for hydrogel formation are described. The physicomechanical properties and applied activities of the resulting materials are also comprehensively discussed. Biodegradable synthetic polymers are outside the scope of this review. © 2020 Society of Chemical Industry.


Assuntos
Agricultura , Biopolímeros/química , Indústria Alimentícia , Hidrogéis/química , Manipulação de Alimentos/métodos
13.
Soft Matter ; 16(5): 1298-1305, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31922166

RESUMO

Soft living tissues like cartilage can be considered as biphasic materials comprising a fibrous complex biopolymer network and a viscous background liquid. Here, we show by a combination of experiment and theoretical analysis that both the hydraulic permeability and the elastic properties of (bio)polymer networks can be determined with simple ramp compression experiments in a commercial rheometer. In our approximate closed-form solution of the poroelastic equations of motion, we find the normal force response during compression as a combination of network stress and fluid pressure. Choosing fibrin as a biopolymer model system with controllable pore size, measurements of the full time-dependent normal force during compression are found to be in excellent agreement with the theoretical calculations. The inferred elastic response of large-pore (µm) fibrin networks depends on the strain rate, suggesting a strong interplay between network elasticity and fluid flow. Phenomenologically extending the calculated normal force into the regime of nonlinear elasticity, we find strain-stiffening of small-pore (sub-µm) fibrin networks to occur at an onset average tangential stress at the gel-plate interface that depends on the polymer concentration in a power-law fashion. The inferred permeability of small-pore fibrin networks scales approximately inverse squared with the fibrin concentration, implying with a microscopic cubic lattice model that the number of protofibrils per fibrin fiber cross-section decreases with protein concentration. Our theoretical model provides a new method to obtain the hydraulic permeability and the elastic properties of biopolymer networks and hydrogels with simple compression experiments, and paves the way to study the relation between fluid flow and elasticity in biopolymer networks during dynamical compression.


Assuntos
Biopolímeros/química , Fibrina/química , Fenômenos Biomecânicos , Elasticidade , Hidrogéis/química , Modelos Biológicos , Permeabilidade , Estresse Mecânico , Viscosidade
14.
Pak J Biol Sci ; 23(2): 139-149, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31944073

RESUMO

BACKGROUND AND OBJECTIVE: Chitinase enzymes have a various application in the field of environmental, biotechnology and medical aspects. This study aimed to the production of the chitinolytic enzymes from different species of bacteria. MATERIALS AND METHODS: Bacterial isolation from different habitats was carried out on agar medium containing chitin as carbon and nitrogen sources. The obtained bacteria (20) were characterized and screened again in chitin broth medium. RESULTS: Out of 20 bacterial isolate, 2 new isolates, belonged to Streptomyces laurentii SN5 and Cellulosimicrobium funkei SN20, were the most active in chitin degradation compared to the other isolates. They have been characterized for the first time for their chitinase activity. They were identified using 16S rRNA gene analysis and in the liquid medium, the 2 isolates have enzyme activities of 0.533 and 0.537 U mL-1, respectively. The maximum chitinase production was obtained when those bacterial strains were grown in Luria-Bertani (LB) broth amended with 1% colloidal chitin, for 1 day and at temperature of 30°C. The optimum pH value for chitinase production was pH 7 for both S. laurentii and C. funkei. The enzyme has been purified using Sephadex G-100 and DEAE-Cellulose chromatography column and found to have a similar molecular size of ~50 kDa. CONCLUSION: Those two bacterial species could be used in chitinase production and in the environmental recycling of disposable chitin wastes such as chitin from shrimp shell waste.


Assuntos
Quitina/química , Quitinases/química , Crustáceos , Streptomyces/enzimologia , Actinobacteria/enzimologia , Animais , Biopolímeros/química , Coloides/química , Concentração de Íons de Hidrogênio , Peso Molecular , Nitrogênio/química , Filogenia , RNA Ribossômico 16S , Temperatura
15.
Chem Soc Rev ; 49(3): 983-1031, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31960001

RESUMO

Biological photonic structures can precisely control light propagation, scattering, and emission via hierarchical structures and diverse chemistry, enabling biophotonic applications for transparency, camouflaging, protection, mimicking and signaling. Corresponding natural polymers are promising building blocks for constructing synthetic multifunctional photonic structures owing to their renewability, biocompatibility, mechanical robustness, ambient processing conditions, and diverse surface chemistry. In this review, we provide a summary of the light phenomena in biophotonic structures found in nature, the selection of corresponding biopolymers for synthetic photonic structures, the fabrication strategies for flexible photonics, and corresponding emerging photonic-related applications. We introduce various photonic structures, including multi-layered, opal, and chiral structures, as well as photonic networks in contrast to traditionally considered light absorption and structural photonics. Next, we summarize the bottom-up and top-down fabrication approaches and physical properties of organized biopolymers and highlight the advantages of biopolymers as building blocks for realizing unique bioenabled photonic structures. Furthermore, we consider the integration of synthetic optically active nanocomponents into organized hierarchical biopolymer frameworks for added optical functionalities, such as enhanced iridescence and chiral photoluminescence. Finally, we present an outlook on current trends in biophotonic materials design and fabrication, including current issues, critical needs, as well as promising emerging photonic applications.


Assuntos
Materiais Biomiméticos/química , Biopolímeros/química , Nanoestruturas/química , Animais , Produtos Biológicos/química , Membranas Artificiais , Estrutura Molecular , Óptica e Fotônica , Processos Fotoquímicos , Proteínas/química , Relação Estrutura-Atividade
16.
PLoS Comput Biol ; 16(1): e1007592, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914131

RESUMO

How homochirality concerning biopolymers (DNA/RNA/proteins) could have originally occurred (i.e., arisen from a non-life chemical world, which tended to be chirality-symmetric) is a long-standing scientific puzzle. For many years, people have focused on exploring plausible physic-chemical mechanisms that may have led to prebiotic environments biased to one chiral type of monomers (e.g., D-nucleotides against L-nucleotides; L-amino-acids against D-amino-acids)-which should have then assembled into corresponding polymers with homochirality, but as yet have achieved no convincing advance. Here we show, by computer simulation-with a model based on the RNA world scenario, that the biased-chirality may have been established at polymer level instead, just deriving from a racemic mixture of monomers (i.e., equally with the two chiral types). In other words, the results suggest that the homochirality may have originated along with the advent of biopolymers during the origin of life, rather than somehow at the level of monomers before the origin of life.


Assuntos
Biopolímeros/química , Evolução Química , Isomerismo , Modelos Biológicos , Aminoácidos/química , Nucleotídeos/química , Origem da Vida
17.
Carbohydr Polym ; 231: 115684, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31888826

RESUMO

We developed a rapid and precise method to determine the fraction of acetylation (FA) of unknown chitosan samples using a combination of enzymatic sample hydrolysis, isotopic labeling, and HILIC-ESI-MS analysis. Chitosans are ß-(1,4)-linked, partially N-acetylated and linear polyglucosamines representing an interesting group of functional biopolymers with a broad range of applications. For a better understanding of their structure-function relationships, it is key to have sensitive, accurate structural analysis tools available to determine parameters like the degree of polymerization (DP), fraction of acetylation (FA), or pattern of acetylation (PA). Here, we describe an improved enzymatic/mass spectrometric method for FA analysis of chitosan polymers. In contrast to the original chitinosanase-based mass spectrometric fingerprinting analysis of FA, the new method is independent of the PA and the intermolecular variation in FA (DFA) of the chitosan sample. This allows accurate analysis of heterogeneously de-N-acetylated samples representing the majority of commercially available chitosans.


Assuntos
Biopolímeros/química , Quitina/química , Quitosana/química , Glucosamina/análogos & derivados , Acetilação , Quitina/síntese química , Quitosana/síntese química , Glucosamina/química , Hidrólise , Marcação por Isótopo , Espectrometria de Massas , Muramidase/química
18.
Lett Appl Microbiol ; 70(4): 300-309, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31891417

RESUMO

Two bacterial strains able to produce polyhydroxyalkanoates (PHAs) from a wide variety of pure carbon sources (dextrose, xylose, sucrose, lactose and glycerol) were isolated from forest soils and identified as Achromobacter mucicolens and Stenotrophomonas rhizophila. Achromobacter mucicolens also produced poly(3-hydroxybutyrate) (PHB) from different wastes (cheese whey, molasses, agave bagasse hydrolysate, nejayote and mango waste pulp). Stenotrophomonas rhizophila, produced the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB-co-HV) from glycerol (7·7 mol% of HV), and from sucrose with addition of propionic or valeric acid (4·5 and 25 mol% of HV, respectively). The copolymers presented a lower melting point (145, 156 and 127°C) and crystallinity (23, 26 and 16%) than PHB. The maximum biopolymer accumulation (PHB) for each strain growing in pure carbon source was as follows: 31·3 g per 100 g dry cell weight (DCW) for A. mucicolens from xylose; and 13·7 g per 100 g DCW for S. rhizophila from sucrose. Regarding the waste carbon sources, the highest PHB accumulation was obtained from agave bagasse hydrolysate (20·4 g per 100 g DCW) by A. mucicolens. The molecular weights of the biopolymers obtained ranged from 200 to 741 kDa. SIGNIFICANCE AND IMPACT OF THE STUDY: The economic cost of the carbon source for the culture of polyhydroxyalkanoates (PHAs)-producing microorganisms is one of the main process limitations. Therefore, it is vital to find versatile microorganisms able to grow and to accumulate homo and copolymers of PHAs from low-cost substrates. In this research, we report two bacterial strains that produce poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) or both from at least five pure and five waste carbon sources. These results, by such bacterial strains have not been reported, especially the production of copolymer from glycerol without addition of precursors by Stenotrophomonas rhizophila and the production of PHB from xylose and agave bagasse hydrolysate by Achromobacter mucicolens.


Assuntos
Biopolímeros/biossíntese , Poli-Hidroxialcanoatos/biossíntese , Microbiologia do Solo , Stenotrophomonas/metabolismo , Biopolímeros/química , Carbono/metabolismo , Florestas , Glicerol/metabolismo , Resíduos Industriais/análise , Peso Molecular , Poli-Hidroxialcanoatos/química , Stenotrophomonas/genética , Stenotrophomonas/isolamento & purificação , Resíduos/análise
19.
Molecules ; 25(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31906348

RESUMO

The synthesis of bioplastic from marine microbes has a great attendance in the realm of biotechnological applications for sustainable eco-management. This study aims to isolate novel strains of poly-ß-hydroxybutyrate (PHB)-producing bacteria from the mangrove rhizosphere, Red Sea, Saudi Arabia, and to characterize the extracted polymer. The efficient marine bacterial isolates were identified by the phylogenetic analysis of the 16S rRNA genes as Tamlana crocina, Bacillus aquimaris, Erythrobacter aquimaris, and Halomonas halophila. The optimization of PHB accumulation by E. aquimaris was achieved at 120 h, pH 8.0, 35 °C, and 2% NaCl, using glucose and peptone as the best carbon and nitrogen sources at a C:N ratio of 9.2:1. The characterization of the extracted biopolymer by Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (NMR), and Gas chromatography-mass spectrometry (GC-MS) proves the presence of hydroxyl, methyl, methylene, methine, and ester carbonyl groups, as well as derivative products of butanoic acid, that confirmed the structure of the polymer as PHB. This is the first report on E. aquimaris as a PHB producer, which promoted the hypothesis that marine rhizospheric bacteria were a new area of research for the production of biopolymers of commercial value.


Assuntos
Biopolímeros/biossíntese , Biopolímeros/química , Hidroxibutiratos/química , Hidroxibutiratos/metabolismo , Poliésteres/química , Poliésteres/metabolismo , Sphingomonadaceae/química , Sphingomonadaceae/metabolismo , Avicennia/microbiologia , Bacillus/química , Bacillus/genética , Bacillus/metabolismo , Biopolímeros/análise , Carbono/química , Carbono/metabolismo , Fermentação , Flavobacteriaceae/química , Flavobacteriaceae/genética , Flavobacteriaceae/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Halomonas/química , Halomonas/genética , Halomonas/metabolismo , Hidroxibutiratos/análise , Espectroscopia de Ressonância Magnética , Nitrogênio/química , Nitrogênio/metabolismo , Filogenia , Poliésteres/análise , RNA Ribossômico 16S/genética , Rizosfera , Salinidade , Arábia Saudita , Água do Mar/microbiologia , Espectroscopia de Infravermelho com Transformada de Fourier , Sphingomonadaceae/genética , Sphingomonadaceae/isolamento & purificação , Temperatura
20.
Molecules ; 25(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31906397

RESUMO

Chinese bayberry leaf proanthocyanidins (BLPs) are Epigallocatechin gallate (EGCG) oligomers or polymers, which have a lot of health-promoting activity. The activity is closely related to their behavior during in vitro digestion, which remains unknown and hinders further investigations. To clarify the changes of BLPs during gastrointestinal digestion, further research is required. For in vitro digestion, including gastric-intestinal digestion, colon fermentation was applied. Caco-2 monolayer transportation was also applied to investigate the behavior of different BLPs with different degrees of polymerization. The trimers and the tetramers were significantly decreased during in vitro gastric-intestinal digestion resulting in a significant increase in the content of dimers. The dimers and trimers were the main compounds utilized by gut microbiota and they were assumed not to degrade through cleavage of the inflavan bond. The monomers and dimers were able to transport through the Caco-2 monolayer at a rate of 10.45% and 6.4%, respectively.


Assuntos
Biopolímeros/metabolismo , Ácido Gálico/análise , Myrica/química , Proantocianidinas/metabolismo , Disponibilidade Biológica , Biopolímeros/análise , Biopolímeros/química , Células CACO-2 , Catequina/análogos & derivados , Catequina/análise , Catequina/química , Catequina/metabolismo , Digestão , Fermentação , Ácido Gálico/química , Ácido Gálico/metabolismo , Mucosa Gástrica/enzimologia , Microbioma Gastrointestinal , Humanos , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Intestinos/enzimologia , Folhas de Planta/química , Polimerização , Proantocianidinas/análise , Proantocianidinas/química , Saliva/enzimologia
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