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1.
Microb Cell Fact ; 19(1): 7, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31931833

RESUMO

BACKGROUND: Therapeutic glycoproteins have occupied an extremely important position in the market of biopharmaceuticals. N-Glycosylation of protein drugs facilitates them to maintain optimal conformations and affect their structural stabilities, serum half-lives and biological efficiencies. Thus homogeneous N-glycoproteins with defined N-glycans are essential in their application in clinic therapeutics. However, there still remain several obstacles to acquire homogeneous N-glycans, such as the high production costs induced by the universal utilization of mammalian cell expression systems, the non-humanized N-glycan structures and the N-glycosylation microheterogeneities between batches. RESULTS: In this study, we constructed a Pichia pastoris (Komagataella phaffii) expression system producing truncated N-GlcNAc-modified recombinant proteins through introducing an ENGase isoform (Endo-T) which possesses powerful hydrolytic activities towards high-mannose type N-glycans. The results showed that the location of Endo-T in different subcellular fractions, such as Endoplasmic reticulum (ER), Golgi or cell membrane, affected their hydrolytic efficiencies. When the Endo-T was expressed in Golgi, the secreted IgG1-Fc region was efficiently produced with almost completely truncated N-glycans and the N-GlcNAc modification on the glycosite Asn297 was confirmed via Mass Spectrometry. CONCLUSION: This strategy develops a simple glycoengineered yeast expression system to produce N-GlcNAc modified proteins, which could be further extended to different N-glycan structures. This system would provide a prospective platform for mass production of increasing novel glycoprotein drugs.


Assuntos
Glicoproteínas/biossíntese , Engenharia Metabólica/métodos , Pichia/metabolismo , Polissacarídeos/biossíntese , Produtos Biológicos , Biotecnologia , Glicoproteínas/química , Glicosilação , Pichia/genética , Polissacarídeos/química , Proteínas Recombinantes/biossíntese , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
2.
Chemosphere ; 247: 125814, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31927186

RESUMO

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


Assuntos
Biomassa , Ciclo do Carbono , Dióxido de Carbono/metabolismo , Carbono/metabolismo , Chlorella/metabolismo , Lipídeos/biossíntese , Microalgas/metabolismo , Fotossíntese , Polissacarídeos/biossíntese , Especificidade da Espécie
3.
Nat Commun ; 11(1): 127, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31913284

RESUMO

Patients infected with the fungal pathogen Cryptococcus are most effectively treated with a combination of 5-fluorocytosine (5FC) and amphotericin B. 5FC acts as a prodrug, which is converted into toxic 5-fluorouracil (5FU) upon uptake into fungal cells. However, the pathogen frequently develops resistance through unclear mechanisms. Here we show that resistance to 5FC in Cryptococcus deuterogattii is acquired more frequently in isolates with defects in DNA mismatch repair that confer an elevated mutation rate. We use whole genome sequencing of 16 independent isolates to identify mutations associated with 5FC resistance in vitro. We find mutations in known resistance genes (FUR1 and FCY2) and in a gene UXS1, previously shown to encode an enzyme that converts UDP-glucuronic acid to UDP-xylose for capsule biosynthesis, but not known to play a role in 5FC metabolism. Mutations in UXS1 lead to accumulation of UDP-glucuronic acid and alterations in nucleotide metabolism, which appear to suppress toxicity of both 5FC and its toxic derivative 5FU.


Assuntos
Antifúngicos/farmacologia , Cryptococcus/efeitos dos fármacos , Cryptococcus/genética , Farmacorresistência Fúngica , Flucitosina/farmacologia , Polissacarídeos/biossíntese , Anfotericina B/farmacologia , Cryptococcus/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Mutação
4.
PLoS Genet ; 15(12): e1008532, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31869330

RESUMO

The human pathogens N. gonorrhoeae and N. meningitidis display robust intra- and interstrain glycan diversity associated with their O-linked protein glycosylation (pgl) systems. In an effort to better understand the evolution and function of protein glycosylation operating there, we aimed to determine if other human-restricted, Neisseria species similarly glycosylate proteins and if so, to assess the levels of glycoform diversity. Comparative genomics revealed the conservation of a subset of genes minimally required for O-linked protein glycosylation glycan and established those pgl genes as core genome constituents of the genus. In conjunction with mass spectrometric-based glycan phenotyping, we found that extant glycoform repertoires in N. gonorrhoeae, N. meningitidis and the closely related species N. polysaccharea and N. lactamica reflect the functional replacement of a progenitor glycan biosynthetic pathway. This replacement involved loss of pgl gene components of the primordial pathway coincident with the acquisition of two exogenous glycosyltransferase genes. Critical to this discovery was the identification of a ubiquitous but previously unrecognized glycosyltransferase gene (pglP) that has uniquely undergone parallel but independent pseudogenization in N. gonorrhoeae and N. meningitidis. We suggest that the pseudogenization events are driven by processes of compositional epistasis leading to gene decay. Additionally, we documented instances where inter-species recombination influences pgl gene status and creates discordant genetic interactions due ostensibly to the multi-locus nature of pgl gene networks. In summary, these findings provide a novel perspective on the evolution of protein glycosylation systems and identify phylogenetically informative, genetic differences associated with Neisseria species.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Neisseria gonorrhoeae/metabolismo , Neisseria meningitidis/metabolismo , Genômica , Glicosilação , Espectrometria de Massas , Neisseria gonorrhoeae/genética , Neisseria meningitidis/genética , Filogenia , Polissacarídeos/biossíntese
5.
Res Vet Sci ; 127: 82-90, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31678457

RESUMO

Pasteurella multocida possesses a polysaccharide capsule composed of a viscous surface layer that acts as a critical structural component and virulence factor. Capsular polysaccharides are structurally similar to vertebrate glycosaminoglycans, providing an immunological mechanism for bacterial molecular mimicry, resistance to phagocytosis, and immune evasion during the infection process. In recent years, a series of important research advances have been made in understanding the biosynthesis and regulatory aspects of the P. multocida capsule. This review systematically examines the serogroups, polysaccharide composition and structures, biosynthetic loci and functions, biosynthesis pathways, and expression regulation mechanisms of the P. multocida capsule, supplying a theoretical basis for the molecular pathogenesis of the P. multocida capsule and the future development of capsular polysaccharide vaccines.


Assuntos
Cápsulas Bacterianas/metabolismo , Vacinas Bacterianas/química , Pasteurella multocida/metabolismo , Polissacarídeos/biossíntese , Fatores de Virulência/metabolismo , Pasteurella multocida/genética , Pasteurella multocida/patogenicidade , Sorogrupo
6.
Int J Mol Sci ; 20(19)2019 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-31569500

RESUMO

Glycosyltransferases that use polyisoprenol-linked donor substrates are categorized in the GT-C superfamily. In eukaryotes, they act in the endoplasmic reticulum (ER) lumen and are involved in N-glycosylation, glypiation, O-mannosylation, and C-mannosylation of proteins. We generated a membrane topology model of C-mannosyltransferases (DPY19 family) that concurred perfectly with the 13 transmembrane domains (TMDs) observed in oligosaccharyltransferases (STT3 family) structures. A multiple alignment of family members from diverse organisms highlighted the presence of only a few conserved amino acids between DPY19s and STT3s. Most of these residues were shown to be essential for DPY19 function and are positioned in luminal loops that showed high conservation within the DPY19 family. Multiple alignments of other eukaryotic GT-C families underlined the presence of similar conserved motifs in luminal loops, in all enzymes of the superfamily. Most GT-C enzymes are proposed to have an uneven number of TDMs with 11 (POMT, TMTC, ALG9, ALG12, PIGB, PIGV, and PIGZ) or 13 (DPY19, STT3, and ALG10) membrane-spanning helices. In contrast, PIGM, ALG3, ALG6, and ALG8 have 12 or 14 TMDs and display a C-terminal dilysine ER-retrieval motif oriented towards the cytoplasm. We propose that all members of the GT-C superfamily are evolutionary related enzymes with preserved membrane topology.


Assuntos
Membrana Celular/química , Glicosiltransferases/química , Proteínas de Membrana/química , Motivos de Aminoácidos , Sequência de Aminoácidos , Sítios de Ligação , Sequência Conservada , Retículo Endoplasmático/metabolismo , Glicosilação , Polissacarídeos/biossíntese , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Relação Estrutura-Atividade
7.
Cell Mol Biol (Noisy-le-grand) ; 65(6): 17-21, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31472043

RESUMO

Chondroitin sulfate (CS) is an important biomedical product. CS is the basic structural component of the mammalian extracellular matrix and is widely used in many applications in the fields of medicine, veterinary medicine, pharmaceuticals and cosmetics. For CS production, mainly animal sources are used. However, in today's conditions, due to various risks and artificial synthesis, there has been an increase in alternative sources of production methods for CS, instead of using animal resources. In this study as a powerful alternative microbial production of CS has been targeted. By using recombinant E. coli strains to integrate VHb /vgb+ and kfo+ systems, the aim was to obtain high purity CS from reliable biotechnological processes. Plasmid pUC8:15 bearing the vgb gene region, and plasmid pETM6-PACF carrying the kfoA, kfoC and kfoF genes responsible for chondroitin synthesis, were transferred to E. coli bacteria. Microbial CS was obtained by adding sulfate groups to chondroitin acquired after the treatments. The results were confirmed by HPLC and NMR analyses. The product, compared to its counterparts, was found to be an effective drug, potentially with a low molecular weight  value.


Assuntos
Cápsulas Bacterianas/metabolismo , Sulfatos de Condroitina/biossíntese , Escherichia coli/genética , Polissacarídeos/biossíntese , Recombinação Genética/genética , Parede Celular/metabolismo , Sulfatos de Condroitina/química , Cromatografia Líquida de Alta Pressão , Espectroscopia de Ressonância Magnética , Plasmídeos/genética , Transformação Genética
8.
Nat Chem Biol ; 15(9): 853-864, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31427814

RESUMO

Glycans linked to proteins and lipids play key roles in biology; thus, accurate replication of cellular glycans is crucial for maintaining function following cell division. The fact that glycans are not copied from genomic templates suggests that fidelity is provided by the catalytic templates of glycosyltransferases that accurately add sugars to specific locations on growing oligosaccharides. To form new glycosidic bonds, glycosyltransferases bind acceptor substrates and orient a specific hydroxyl group, frequently one of many, for attack of the donor sugar anomeric carbon. Several recent crystal structures of glycosyltransferases with bound acceptor substrates reveal that these enzymes have common core structures that function as scaffolds upon which variable loops are inserted to confer substrate specificity and correctly orient the nucleophilic hydroxyl group. The varied approaches for acceptor binding site assembly suggest an ongoing evolution of these loop regions provides templates for assembly of the diverse glycan structures observed in biology.


Assuntos
Glicosiltransferases/metabolismo , Polissacarídeos/biossíntese , Polissacarídeos/química , Animais , Configuração de Carboidratos , Bases de Dados de Proteínas , Regulação Enzimológica da Expressão Gênica
9.
Plant Sci ; 286: 49-56, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300141

RESUMO

Progress in the functional biochemical analysis of plant glycosyltransferases (GTs) has been slow because plant GTs are generally membrane proteins, operate as part of larger, multimeric complexes, and utilize a vast complexity of substrate acceptors. Therefore, the field would benefit from development of adequate high throughput expression as well as product detection and characterization techniques. Here we review current approaches to tackle such obstacles and suggest a new path forward: nucleic acid programmable protein arrays (NAPPA) with liquid sample desorption ionization (LS-DESI-MS) mass spectrometry. NAPPA utilizes in vitro transcription and translation to produce epitope-tagged fusion proteins from cloned GT cDNAs. LS-DESI is a soft ionization technique that allows rapid and sensitive MS-based product characterization in situ. Coupling both approaches provides the opportunity to examine individual GT functions as well as protein-protein interactions. Furthermore, advances in automated oligosaccharide synthesis and lipid nanodisc technology should allow testing of plant GT activity in presence of numerous substrate acceptors and lipid environments in a high throughput fashion. Thus, NAPPA-DESI-MS has great potential to make headway in biochemical characterization of the large number of plant GTs.


Assuntos
Parede Celular/química , Ensaios de Triagem em Larga Escala/métodos , Plantas/química , Polissacarídeos/biossíntese , Análise Serial de Proteínas/métodos , Glicosiltransferases/análise , Espectrometria de Massas/métodos , Proteínas de Plantas/análise , Plantas/enzimologia
10.
BMC Bioinformatics ; 20(1): 357, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31248364

RESUMO

BACKGROUND: C4 photosynthesis is a key domain of plant research with outcomes ranging from crop quality improvement, biofuel production and efficient use of water and nutrients. A metabolic network model of C4 "lab organism" Setaria viridis with extensive gene-reaction associations can accelerate target identification for desired metabolic manipulations and thereafter in vivo validation. Moreover, metabolic reconstructions have also been shown to be a significant tool to investigate fundamental metabolic traits. RESULTS: A mass and charge balance genome-scale metabolic model of Setaria viridis was constructed, which was tested to be able to produce all major biomass components in phototrophic and heterotrophic conditions. Our model predicted an important role of the utilization of NH[Formula: see text] and NO[Formula: see text] ratio in balancing charges in plants. A multi-tissue extension of the model representing C4 photosynthesis was able to utilize NADP-ME subtype of C4 carbon fixation for the production of lignocellulosic biomass in stem, providing a tool for identifying gene associations for cellulose, hemi-cellulose and lignin biosynthesis that could be potential target for improved lignocellulosic biomass production. Besides metabolic engineering, our modeling results uncovered a previously unrecognized role of the 3-PGA/triosephosphate shuttle in proton balancing. CONCLUSIONS: A mass and charge balance model of Setaria viridis, a model C4 plant, provides the possibility of system-level investigation to identify metabolic characteristics based on stoichiometric constraints. This study demonstrated the use of metabolic modeling in identifying genes associated with the synthesis of particular biomass components, and elucidating new role of previously known metabolic processes.


Assuntos
Prótons , Setaria (Planta)/metabolismo , Biomassa , Celulose/biossíntese , Genoma de Planta , Lignina/biossíntese , Redes e Vias Metabólicas , Modelos Biológicos , Fotossíntese , Polissacarídeos/biossíntese , Setaria (Planta)/genética
11.
Zhongguo Zhong Yao Za Zhi ; 44(8): 1552-1557, 2019 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-31090318

RESUMO

In order to understand the function of GDP-mannose pyrophosphorylase(GMPP) function and its regulation in polysaccharide biosynthesis mechanism in Dendrobium. D. huoshanense was used to clone GMPP gene. GMPP gene expression in D. huoshanense,D. officinale and D. moniliforme was also determined by qPCR. The results showed that the length of D. huoshanense GMPP gene c DNA sequence is 1 867 bp,containing 1 245 bp open reading frame(ORF),encoding 415 amino acids. Phylogenetic tree analysis showed that D. huoshanense,D. officinale and D. moniliforme are closely related with GMPP taken into consideration. Bioinformatics analysis demonstrated that GMPP sequence similarity among the three species reached as high as 99%. qPCR results indicated that GMPP genes was highly expressed in stem of D. huoshanense compared with its leaf,flower and root. According to GMPP gene expression profile in D. huoshanense,D. officinale and D. moniliforme grown in Huoshan area,it was clear that GMPP in D. huoshanense showed the highest expression level. Furthermore,our findings of GMPP gene expression profile will facilitate future researches into its polysaccharide biosynthetic mechanism.


Assuntos
Dendrobium/genética , Nucleotidiltransferases/genética , Proteínas de Plantas/genética , Sequência de Bases , Clonagem Molecular , Dendrobium/enzimologia , Filogenia , Polissacarídeos/biossíntese
12.
Int J Biol Macromol ; 135: 1-11, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31121228

RESUMO

Microalgae are the lowest plant organisms producing a wide range of metabolites that make them interesting organisms for industrial applications. Cultivation of green microalgal species Chlorella vulgaris resulted a significant production of extracellular polysaccharide (EPS). Preliminary chemico-spectroscopic studies on EPS revealed its molecular profile, a complex primary structure consisting of six monosaccharide units occurring in both furano and pyrano forms, a high sugar binding variability and the presence of partially methylated derivatives of some sugar constituents. Biological activity tests showed that EPS caused significant bronchodilatory, anti-inflammatory and antitussive effects in test animals. Chlorella EPS appears to be a promising agent for the prevention of chronic airway inflammation, which is the basic pathogenic mechanism of many respiratory diseases, including bronchial asthma.


Assuntos
Antiasmáticos/química , Antiasmáticos/farmacologia , Chlorella vulgaris/metabolismo , Polissacarídeos/química , Polissacarídeos/farmacologia , Alérgenos , Animais , Antiasmáticos/metabolismo , Hiper-Reatividade Brônquica/tratamento farmacológico , Hiper-Reatividade Brônquica/imunologia , Hiper-Reatividade Brônquica/fisiopatologia , Fenômenos Químicos , Citocinas/metabolismo , Modelos Animais de Doenças , Espaço Extracelular/metabolismo , Cobaias , Mediadores da Inflamação/metabolismo , Masculino , Músculo Liso/efeitos dos fármacos , Músculo Liso/imunologia , Músculo Liso/metabolismo , Polissacarídeos/biossíntese , Análise Espectral
13.
Colloids Surf B Biointerfaces ; 181: 25-30, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31121378

RESUMO

This work aims to encapsulate nisin by complexation with exopolysaccharides (EPS), produced by Bacillus tequilensis-GM and Leuconostoc citreum-BMS, namely EPS-GM and EPS-BMS, respectively, using spray-drying technique, and to evaluate the effect of this encapsulation on the structure of nisin. Results related to suspensions turbidity showed that EPS/nisin complexes were formed through electrostatic attractions. These interactions were confirmed by Fourier transform infrared (FTIR) analysis. Scanning electron microscopy (SEM) micrographs of the spray-dried complexes revealed the presence of well-separated spherical microcapsules. Besides, results obtained by UV spectra showed that no significant changes occurred on EPS-GM/nisin microcapsules suggesting that this EPS may act as protective agent of nisin structure against spray-drying conditions.


Assuntos
Bacillus/química , Dessecação , Leuconostoc/química , Nisina/química , Polissacarídeos/química , Substâncias Protetoras/química , Bacillus/metabolismo , Leuconostoc/metabolismo , Tamanho da Partícula , Polissacarídeos/biossíntese , Substâncias Protetoras/metabolismo , Eletricidade Estática , Propriedades de Superfície
14.
Carbohydr Polym ; 216: 204-212, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31047058

RESUMO

Sulfated polysaccharides (SPSs) are polysaccharides (PSs) with high sulfate functionalization and possess bioactivities. This study aimed to increase the sulfate content of SPSs in Antrodia cinnamomea through sulfate feeding. Feeding A. cinnamomea with sodium thiosulfate was found to increase yields of PSs and SPSs in A. cinnamomea. The SPSs thus obtained (ST-SPS) were further isolated, showing enhanced sulfate content of 2.5 mmol/g. Sodium thiosulfate induced changes in molecular weight from 320 kDa to 1342 kDa, and area percentage of low-molecular-weight ST-SPS (< 20 kDa) was decreased. Functional studies revealed that sodium thiosulfate increased the ST-SPS anticancer efficacy in cancer cells via inhibition of EGFR/AKT signaling. Moreover, the ST-SPS enhanced synergistically cisplatin-, gefitinib- and 5 FU-induced cytotoxic effects in lung cancer H1975 cells and colon cancer CT26 cells. This study is the first to demonstrate that sodium thiosulfate induced changes in properties of A. cinnamomea with the anticancer mechanisms of ST-SPS.


Assuntos
Antineoplásicos/farmacologia , Antrodia/química , Antrodia/metabolismo , Polissacarídeos/farmacologia , Ésteres do Ácido Sulfúrico/farmacologia , Tiossulfatos/metabolismo , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Cisplatino/farmacologia , Sinergismo Farmacológico , Receptores ErbB/metabolismo , Fluoruracila/farmacologia , Gefitinibe/farmacologia , Humanos , Concentração Inibidora 50 , Camundongos , Peso Molecular , Fosforilação/efeitos dos fármacos , Polissacarídeos/biossíntese , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Transdução de Sinais/efeitos dos fármacos , Ésteres do Ácido Sulfúrico/química , Ésteres do Ácido Sulfúrico/isolamento & purificação , Ésteres do Ácido Sulfúrico/metabolismo
15.
Appl Microbiol Biotechnol ; 103(11): 4565-4574, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31011774

RESUMO

Biosurfactants are amphiphilic compounds that composed of hydrophilic and hydrophobic moieties, which possess the ability of self-organizing between phases, reducing the interfacial tension, and forming aggregates such as micelles. This spontaneous process results in significant changes in surface properties that directly influence the adherence of microorganisms. In this study, the ability of surfactin, a biosurfactant produced by Bacillus subtilis in reducing adhesion and disrupting the presence of biofilm of Staphylococcus aureus (S. aureus) on several surfaces, was investigated. Significant biofilm removal was observed on glass, polystyrene, and stainless steel surfaces. Furthermore, we explored the probable mechanism about how surfactin affected S. aureus biofilm formation. Based on our findings, surfactin had a significant effect on the polysaccharides production and especially decreased the percentage of alkali-soluble polysaccharide in biofilms. It also down-regulated the expression of icaA and icaD significantly, which are necessary for the important constituents to take shape of staphylococcal biofilm. In addition, it was found that the lipopeptide affected the quorum sensing (QS) system in S. aureus through regulating the auto inducer 2 (AI-2) activity, which has been reported to be negative for biofilm formation in S. aureus. These above properties could be applied in developing surfactin as a potential pre-coating agent on material surfaces to prevent S. aureus biofilm formation.


Assuntos
Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Lipopeptídeos/metabolismo , Peptídeos Cíclicos/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Bacillus subtilis/química , Vias Biossintéticas/efeitos dos fármacos , Microbiologia Ambiental , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Lipopeptídeos/isolamento & purificação , Peptídeos Cíclicos/isolamento & purificação , Polissacarídeos/biossíntese , Percepção de Quorum/efeitos dos fármacos , Propriedades de Superfície/efeitos dos fármacos
16.
Int J Biol Macromol ; 132: 915-921, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30959133

RESUMO

Lactic acid bacteria fermentation is an important processing technology for fruits and vegetables. Bioactive compounds such as polysaccharides are altered during the fermentation process. Polysaccharides from longan pulp (LPs) were extracted after different fermentation times and their physicochemical and prebiotic properties were investigated, such as longan polysaccharides named LP-0 and LP-12 means they were extracted from longan pulp fermented for 0 and 12 h, respectively. The yield, contents of neutral sugar and uronic acid, molecular weight (Mw), and monosaccharide composition of LPs were significantly changed with different fermentation times. Specially, the yield and uronic acid content of LPs were first increase and then decline. LP-12 contained the smallest Mw (108.71 ±â€¯5.55 kDa) of the tested LPs (p < 0.05). When compared with unfermented LP-0, the glucose molar percentages of fermented LPs declined, while those of rhamnose and galactose increased, except for LP-6. Fermented LPs also exhibited a stronger stimulatory effect on Lactobacillus strain proliferation, with the proliferative effect of LP-12 being the strongest (p < 0.05). These results suggest that lactic acid bacteria fermentation can change the physicochemical properties and enhance the prebiotic activities of polysaccharides from longan pulp.


Assuntos
Fermentação , Polissacarídeos/química , Polissacarídeos/farmacologia , Prebióticos , Sapindaceae/metabolismo , Fenômenos Químicos , Lactobacillus acidophilus/efeitos dos fármacos , Polissacarídeos/biossíntese
17.
Microb Pathog ; 132: 10-19, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31002963

RESUMO

A new exopolysaccharide (EPS) was produced by the Lactococcus lactis F-mou strain (LT898177.1) isolated from the Sahrawi camel milk in the Bir-Naam region, Algeria. The most influential production parameters were screened by the Plackett-Burman design for enhancing EPS yield utilizing the Mech-Degla juice as a low-cost raw material. An optimum condition of a 0.49 of inoculum size, a 100 rpm of agitation rate, and a 12 h of incubation period resulted in a 301 g/L. This yield was 47 times higher than the one attained before the application of the Box-Behnken Design. Additionally, the FTIR analysis of the EPS confirmed the presence of hydroxyl, carboxyl, amide and sulphate groups. Furthermore, the SEM image showed a porous structure characterized by a flake-like basic configuration with an extremely dense assembly. The NMR studies indicated that EPS contained a backbone of→4-α-D-galactopyranose-(1→, →4, 6-α-D-glucopyranose-(1→, →6- α -D- galactopyranose -(1→ linkages plus a levan part. The EPS exhibited good water and oil holding capacities, a high antioxidant efficiency, and an excellent anti-clotting activity. EPS also showed a strong inhibitory activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Listeria monocytogenes, Bacillus cereus, Proteus mirabilis, Acinetobacter baumannii, Enterobacter cloacae, and Candida albicans. Overall, the mentioned findings indicated that EPS could be utilized as a natural additive in pharmaceutical, food, and cosmetic industries.


Assuntos
Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Lactococcus lactis/metabolismo , Polissacarídeos/biossíntese , Polissacarídeos/farmacologia , Animais , Anti-Infecciosos/isolamento & purificação , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Camelus , Emulsificantes , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Leite/microbiologia , RNA Ribossômico 16S/genética
18.
Prog Mol Biol Transl Sci ; 162: 1-24, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30905444

RESUMO

Glycans are essential biomolecules in regulating human physiology and pathology ranging from signal transduction to microbial infections. Developing complex human diseases, such as cancer, diabetes, and cardiovascular diseases, are a combination of genetic and environmental factors. Genetics dominates embryonic development and the passing of genes to the next generation whereas the information in glycans reflects the impact of internal and external environmental factors, such as diseases, lifestyle, and social factors, on a person's health and disease. The reason behind this is that glycans are not directly encoded in a genetic template. Instead, they are assembled dynamically by hundreds of enzymes organized in more than 10 complex biosynthetic pathways. Any environmental changes affecting enzymatic activities or the availability of high-energy monosaccharide donors in a specific location will disturb the final structure of glycans. The glycan structure-dependent biological activities subsequently enable or disable gene expressions, which partially explain that it is difficult to pinpoint specific genetic defects to aging-associated diseases. Glycan-based biomarkers are currently used for diagnosis of diabetes, cancers, and other complex diseases. We will recapitulate the discovery of glucose, glycated proteins, glycan-, and glycoprotein-based biomarkers followed by summarizing clinically used glycan/glycoprotein-based biomarkers. The potential serum/plasma-derived N- and O-linked glycans as biomarkers will also be discussed.


Assuntos
Biomarcadores Tumorais/sangue , Neoplasias/sangue , Neoplasias/diagnóstico , Polissacarídeos/sangue , Glicemia/análise , Glicoproteínas/sangue , Humanos , Polissacarídeos/biossíntese , Polissacarídeos/química
19.
Mol Biol Evol ; 36(5): 1056-1070, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30835283

RESUMO

Observations of bacteria at the single-cell level have revealed many instances of phenotypic heterogeneity within otherwise clonal populations, but the selective causes, molecular bases, and broader ecological relevance remain poorly understood. In an earlier experiment in which the bacterium Pseudomonas fluorescens SBW25 was propagated under a selective regime that mimicked the host immune response, a genotype evolved that stochastically switched between capsulation states. The genetic cause was a mutation in carB that decreased the pyrimidine pool (and growth rate), lowering the activation threshold of a preexisting but hitherto unrecognized phenotypic switch. Genetic components surrounding bifurcation of UTP flux toward DNA/RNA or UDP-glucose (a precursor of colanic acid forming the capsules) were implicated as key components. Extending these molecular analyses-and based on a combination of genetics, transcriptomics, biochemistry, and mathematical modeling-we show that pyrimidine limitation triggers an increase in ribosome biosynthesis and that switching is caused by competition between ribosomes and CsrA/RsmA proteins for the mRNA transcript of a positively autoregulated activator of colanic acid biosynthesis. We additionally show that in the ancestral bacterium the switch is part of a program that determines stochastic entry into a semiquiescent capsulated state, ensures that such cells are provisioned with excess ribosomes, and enables provisioned cells to exit rapidly from stationary phase under permissive conditions.


Assuntos
Cápsulas Bacterianas/fisiologia , Ribossomos/metabolismo , Escherichia coli , Regulação Bacteriana da Expressão Gênica , Genes de Troca , Modelos Genéticos , Polissacarídeos/biossíntese , Pseudomonas fluorescens
20.
Methods Mol Biol ; 1923: 227-241, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30737743

RESUMO

The ability to control and adjust the N-glycosylation pathway of Saccharomyces cerevisiae is a key step toward production of therapeutic glycoproteins such as antibodies or erythropoietin. The focus of this chapter is to describe the road from yeast-type N-glycosylation to human-type complex N-glycosylation. The chapter describes the cell engineering and provides the detailed analytical procedures required to perform glycan analysis using MALDI-TOF mass spectrometry.


Assuntos
Polissacarídeos/biossíntese , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Glicoproteínas/genética , Glicoproteínas/metabolismo , Glicosilação , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
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