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1.
Mol Microbiol ; 115(4): 658-671, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33084151

RESUMEN

Streptococcus sanguinis is a primary colonizer of teeth and is associated with oral health. When it enters the bloodstream, however, this bacterium may cause the serious illness infective endocarditis. The genes required for survival and proliferation in blood have not been identified. The products of these genes could provide a rich source of targets for endocarditis-specific antibiotics possessing greater efficacy for endocarditis, and also little or no activity against those bacteria that remain in the mouth. We previously created a comprehensive library of S. sanguinis mutants lacking every nonessential gene. We have now screened each member of this library for growth in human serum and discovered 178 mutants with significant abundance changes. The main biological functions disrupted in these mutants, including purine metabolism, were highlighted via network analysis. The components of an ECF-family transporter were required for growth in serum and were shown for the first time in any bacterium to be essential for endocarditis virulence. We also identified two mutants whose growth was reduced in serum but not in saliva. This strategy promises to enable selective targeting of bacteria based on their location in the body, in this instance, treating or preventing endocarditis while leaving the oral microbiome intact.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/genética , Sangre/microbiología , Aptitud Genética , Proteínas de Transporte de Membrana/genética , Streptococcus sanguis/genética , Streptococcus sanguis/metabolismo , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , ADN Bacteriano , Endocarditis Bacteriana/microbiología , Estudio de Asociación del Genoma Completo/métodos , Humanos , Masculino , Proteínas de Transporte de Membrana/metabolismo , Redes y Vías Metabólicas , Mutación , Purinas/metabolismo , Conejos , Saliva/microbiología , Organismos Libres de Patógenos Específicos , Infecciones Estreptocócicas/microbiología , Streptococcus sanguis/patogenicidad , Virulencia , Factores de Virulencia/genética , Factores de Virulencia/metabolismo
2.
J Nanobiotechnology ; 20(1): 476, 2022 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-36369077

RESUMEN

Multidrug resistance (MDR) has been restricting the efficacy of chemotherapy, which mainly include pump resistance and non-pump resistance. In order to fight overall MDR, a novel targeted gene/drug co-deliver nano system is developed, which can suppress the drug efflux pumps and modulate autophagy to overcoming both pump and non-pump resistance. Here, small interfere RNA (siRNA) is incorporated into polymer-drug conjugates (PEI-PTX, PP) which are composed of polyethyleneimine (PEI) and paclitaxel (PTX) via covalent bonds, and hyaluronic acid (HA) is coated on the surface of PP/siRNA to achieve long blood cycle and CD44-targeted delivery. The RNA interference to mdr1 gene is combined with autophagy inhibition by PP, which efficiently facilitate apoptosis of Taxol-resistant lung cancer cells (A549/T). Further study indicates that PEI in PP may play a significant role to block the autophagosome-lysosome fusion process by means of alkalizing lysosomes. Both in vitro and in vivo studies confirm that the nanoassemblies can successfully deliver PTX and siRNA into tumor cells and significantly inhibited A549/T tumor growth. In summary, the polymeric nanoassemblies provide a potential strategy for combating both pump and non-pump resistance via the synergism of RNAi and autophagy modulation.


Asunto(s)
Nanopartículas , Neoplasias , Profármacos , Humanos , ARN Interferente Pequeño/farmacología , Resistencia a Antineoplásicos , Resistencia a Múltiples Medicamentos , Paclitaxel/farmacología , Paclitaxel/química , Polietileneimina/química , Neoplasias/tratamiento farmacológico , Autofagia , Línea Celular Tumoral , Nanopartículas/química
3.
Plant Mol Biol ; 105(6): 625-635, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33481140

RESUMEN

KEY MESSAGE: IEF, a novel plasma plasma membrane protein, is important for exine formation in Arabidopsis. Exine, an important part of pollen wall, is crucial for male fertility. The major component of exine is sporopollenin which are synthesized and secreted by tapetum. Although sporopollenin synthesis has been well studied, the transportation of it remains elusive. To understand it, we analyzed the gene expression pattern in tapetal microdissection data, and investigated the potential transporter genes that are putatively regulated by ABORTED MICROSPORES (AMS). Among these genes, we identified IMPERFECTIVE EXINE FORMATION (IEF) that is important for exine formation. Compared to the wild type, ief mutants exhibit severe male sterility and pollen abortion, suggesting IEF is crucial for pollen development and male fertility. Using both scanning and transmission electron microscopes, we showed that exine structure was not well defined in ief mutant. The transient expression of IEF-GFP driven by the 35S promoter indicated that IEF-GFP was localized in plasma membrane. Furthermore, AMS can specifically activate the expression of promoterIEF:LUC in vitro, which suggesting AMS regulates IEF for exine formation. The expression of ATP-BINDING CASSETTE TRANSPORTER G26 (AGCB26) was not affected in ief mutants. In addition, SEM and TEM data showed that the sporopollenin deposition is more defective in abcg26/ief-2 than that of in abcg26, which suggesting that IEF is involved in an independent sporopollenin transportation pathway. This work reveal a novel gene, IEF regulated by AMS that is essential for exine formation.


Asunto(s)
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Fertilidad/fisiología , Transportadoras de Casetes de Unión a ATP/metabolismo , Arabidopsis/crecimiento & desarrollo , Transporte Biológico , Biopolímeros/biosíntesis , Carotenoides/metabolismo , Fertilidad/genética , Regulación de la Expresión Génica de las Plantas , Polen , Nicotiana
4.
Mikrochim Acta ; 188(9): 301, 2021 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-34409498

RESUMEN

An ultrathin micro-patterned MXene/PEDOT:PSS-based organic electrochemical transistor biosensor was constructed, which can significantly amplify the amperometric signal and transistor's performance. A novel interdigitated OECTs biosensor has been developed for reliable determination of survivin for the following considerations: (1) The synergistic effect of intercalated MXene and ionic PEDOT:PSS enhanced the mobility and volumetric capacitance of OECTs biosensor. (2) Compared with the best previous literatures, our assay demonstrated enhanced detection limit of survivin down to 10 pg mL-1, as well as satisfactory selectivity, reproducibility, and reliability. (3) Comparison of OECTs against commercial ELISA kit yielded favorable linearity (Y = 1.0015*X + 0.0039) and correlation coefficient (R2 = 0.9717). Those advantages are expected to pave the way to design of an OECTs biosensor with robustness, non-invasiveness, and miniaturization for the point-of-care applications.


Asunto(s)
Electroquímica/métodos , Osteosarcoma/terapia , Poliestirenos/uso terapéutico , Survivin/metabolismo , Niño , Humanos , Poliestirenos/farmacología
5.
Plant Physiol ; 181(2): 645-655, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31345954

RESUMEN

The timely release of mature pollen following anther dehiscence is essential for reproduction in flowering plants. AUXIN RESPONSE FACTOR17 (ARF17) plays a crucial role in pollen wall pattern formation, tapetum development, and auxin signal transduction in anthers. Here, we showed that ARF17 is also involved in anther dehiscence. The Arabidopsis (Arabidopsis thaliana) arf17 mutant exhibits defective endothecium lignification, which leads to defects in anther dehiscence. The expression of MYB108, which encodes a transcription factor important for anther dehiscence, was dramatically down-regulated in the flower buds of arf17 Chromatin immunoprecipitation assays and electrophoretic mobility shift assays showed ARF17 directly binds to the MYB108 promoter. In an ARF17-GFP transgenic line, in which ARF17-GFP fully complements the arf17 phenotype, ARF17-GFP was observed in the endothecia at anther stage 11. The GUS signal driven by the MYB108 promoter was also detected in endothecia at late anther stages in transgenic plants expressing promoterMYB108::GUS Thus, the expression pattern of both ARF17 and MYB108 is consistent with the function of these genes in anther dehiscence. Furthermore, the expression of MYB108 driven by the ARF17 promoter successfully restored the defects in anther dehiscence of arf17 These results demonstrated that ARF17 regulates the expression of MYB108 for anther dehiscence. Together with its function in microcytes and tapeta, ARF17 likely coordinates the development of different sporophytic cell layers in anthers. The ARF17-MYB108 pathway involved in regulating anther dehiscence is also discussed.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiología , Arabidopsis/fisiología , Flores/fisiología , Factores de Transcripción/metabolismo , Factores de Transcripción/fisiología , Lignina/metabolismo
6.
J Am Chem Soc ; 140(47): 16001-16005, 2018 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-30376327

RESUMEN

Value-added utilization of lignin waste streams is vital to fully sustainable and economically viable biorefineries. However, deriving substantial value from its main constituents is seriously hindered by the constant requirement for expensive coenzymes. Herein, we devised a coenzyme-free biocatalyst that could transform lignin-derived aromatics into various attractive pharmaceutical and polymer building blocks. At the center of our strategy is the integrated use of new mining phenolic acid decarboxylase and aromatic dioxygenase with extremely high catalytic efficiency, which realizes the value-added utilization of lignin in a coenzyme-independent manner. Notably, a new temperature/pH-directed strategy was proposed to eliminate the highly redundant activities of endogenous alcohol dehydrogenases. The major components of lignin were simultaneously converted to vanillin and 4-vinylphenol. Since the versatile biocatalyst could efficiently convert many other renewable lignin-related aromatics to valuable chemicals, this green route paves the way for enhancing the entire efficiency of biorefineries.


Asunto(s)
Derivados del Benceno/química , Carboxiliasas/química , Oxigenasas de Función Mixta/química , Ascomicetos/enzimología , Bacillus coagulans/enzimología , Benzaldehídos/síntesis química , Biocatálisis , Cinamatos/química , Escherichia coli/genética , Concentración de Iones de Hidrógeno , Lignina/química , Estirenos/síntesis química , Temperatura
7.
Microbiology (Reading) ; 164(2): 173-185, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-29393020

RESUMEN

The paradoxical response of Streptococcus sanguinis to drugs prescribed for dental and clinical practices has complicated treatment guidelines and raised the need for further investigation. We conducted a high throughput study on concomitant transcriptome and proteome dynamics in a time course to assess S. sanguinis behaviour under a sub-inhibitory concentration of ampicillin. Temporal changes at the transcriptome and proteome level were monitored to cover essential genes and proteins over a physiological map of intricate pathways. Our findings revealed that translation was the functional category in S. sanguinis that was most enriched in essential proteins. Moreover, essential proteins in this category demonstrated the greatest conservation across 2774 bacterial proteomes, in comparison to other essential functional categories like cell wall biosynthesis and energy production. In comparison to non-essential proteins, essential proteins were less likely to contain 'degradation-prone' amino acids at their N-terminal position, suggesting a longer half-life. Despite the ampicillin-induced stress, the transcriptional up-regulation of amino acid-tRNA synthetases and proteomic elevation of amino acid biosynthesis enzymes favoured the enriched components of essential proteins revealing 'proteomic signatures' that can be used to bridge the genotype-phenotype gap of S. sanguinis under ampicillin stress. Furthermore, we identified a significant correlation between the levels of mRNA and protein for essential genes and detected essential protein-enriched pathways differentially regulated through a persistent stress response pattern at late time points. We propose that the current findings will help characterize a bacterial model to study the dynamics of essential genes and proteins under clinically relevant stress conditions.


Asunto(s)
Antibacterianos/metabolismo , Genes Bacterianos/genética , Genes Esenciales/genética , Streptococcus sanguis/fisiología , Estrés Fisiológico/genética , Ampicilina/metabolismo , Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica/fisiología , Cinética , Redes y Vías Metabólicas/genética , Anotación de Secuencia Molecular , Proteoma/genética , Proteoma/metabolismo , Streptococcus sanguis/genética , Streptococcus sanguis/metabolismo , Transcriptoma/fisiología
8.
Bioorg Med Chem Lett ; 27(16): 3840-3844, 2017 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-28668193

RESUMEN

Two diastereomeric analogs (1 and 2) of diaminopimelic acid (DAP) bearing an isoxazoline moiety were synthesized and evaluated for their inhibitory activities against meso-diaminopimelate dehydrogenase (m-Ddh) from the periodontal pathogen, Porphyromonas gingivalis. Compound 2 showed promising inhibitory activity against m-Ddh with an IC50 value of 14.9µM at pH 7.8. The two compounds were further tested for their antibacterial activities against a panel of periodontal pathogens, and compound 2 was shown to be selectively potent to P. gingivalis strains W83 and ATCC 33277 with minimum inhibitory concentration (MIC) values of 773µM and 1.875mM, respectively. Molecular modeling studies revealed that the inversion of chirality at the C-5 position of these compounds was the primary reason for their different biological profiles. Based on these preliminary results, we believe that compound 2 has properties consistent with it being a lead compound for developing novel pathogen selective antibiotics to treat periodontal diseases.


Asunto(s)
Aminoácido Oxidorreductasas/antagonistas & inhibidores , Antibacterianos/farmacología , Ácido Diaminopimélico/farmacología , Inhibidores Enzimáticos/farmacología , Isoxazoles/farmacología , Porphyromonas gingivalis/efectos de los fármacos , Aminoácido Oxidorreductasas/metabolismo , Antibacterianos/síntesis química , Antibacterianos/química , Ácido Diaminopimélico/síntesis química , Ácido Diaminopimélico/química , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Isoxazoles/química , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Estructura Molecular , Porphyromonas gingivalis/enzimología , Relación Estructura-Actividad
9.
Chembiochem ; 17(16): 1491-4, 2016 08 17.
Artículo en Inglés | MEDLINE | ID: mdl-27237045

RESUMEN

High production of polymer-grade d-lactic acid is urgently required, particularly for the synthesis of polylactic acid. High-temperature fermentation has multiple advantages, such as lower equipment requirement and energy consumption, which are essential for lowering operating costs. We identified and introduced a unique d-lactate dehydrogenase into a thermotolerant butane-2,3-diol-producing strain. Carbon flux "trapping" was achieved by a "trapping point" created by combination of the introduced enzyme and the host efflux pump, which afforded irreversible transport of d-lactic acid. The overall carbon flux of the engineered strain was significantly enhanced and was redistributed predominantly to d-lactic acid. Under optimized conditions at 50 °C, d-lactic acid reached the highest titer (226.6 g L(-1) ) reported to date. This discovery allows us to extend the carbon flux trapping strategy to engineering complex metabolic networks.


Asunto(s)
Ciclo del Carbono , Lactato Deshidrogenasas/metabolismo , Ácido Láctico/biosíntesis , Polímeros/metabolismo , Temperatura , Lactato Deshidrogenasas/química , Ácido Láctico/química , Polímeros/química , Factores de Tiempo
10.
Bioorg Med Chem ; 24(16): 3472-82, 2016 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-27288186

RESUMEN

Enterovirus 71 (EV71) is a kind of RNA virus and one of the two causes of Hand, foot and mouth disease (HFMD). Inhibitors that target key components of Ras/Raf/MEK/ERK pathway in host cells could impair replication of EV71. A series of 3-benzyl-1,3-benzoxazine-2,4-diones were designed from a specific MEK inhibitor G8935, by replacing the double bond between C3 and C4 within the coumarin scaffold with amide bond. One compound (9f) showed submicromolar inhibitory activity among the 12 derivatives. Further optimization on 9f led to two active compounds (9k and 9m) with nanomolar bioactivities (55nM and 60nM). The results of enzymatic assays also demonstrated that this series of compounds were allosteric inhibitors of unphosphorylated MEK1. The binding mode of compound 9k was predicted by molecular dynamic simulation and the key interactions were same as published MEK1/2 allosteric inhibitors. In the cell-based assays, compounds 9k and 9m could effectively suppress the ERK1/2 pathway, expression of EV71 VP1, and EV71 induced cytopathic effect (CPE) in rhabdomyosarcoma (RD) cells.


Asunto(s)
Antivirales/farmacología , Enterovirus Humano A/efectos de los fármacos , Quinasas MAP Reguladas por Señal Extracelular/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/farmacología , Regulación Alostérica , Antivirales/química , Línea Celular , Descubrimiento de Drogas , Humanos , Inhibidores de Proteínas Quinasas/química
11.
Mol Microbiol ; 92(6): 1243-59, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24750294

RESUMEN

Streptococcus sanguinis colonizes teeth and is an important cause of infective endocarditis. Our prior work showed that the lipoprotein SsaB is critical for S. sanguinis virulence for endocarditis and belongs to the LraI family of conserved metal transporters. In this study, we demonstrated that an ssaB mutant accumulates less manganese and iron than its parent. A mutant lacking the manganese-dependent superoxide dismutase, SodA, was significantly less virulent than wild-type in a rabbit model of endocarditis, but significantly more virulent than the ssaB mutant. Neither the ssaB nor the sodA mutation affected sensitivity to phagocytic killing or efficiency of heart valve colonization. Animal virulence results for all strains could be reproduced by growing bacteria in serum under physiological levels of O(2). SodA activity was reduced, but not eliminated in the ssaB mutant in serum and in rabbits. Growth of the ssaB mutant in serum was restored upon addition of Mn(2+) or removal of O(2). Antioxidant supplementation experiments suggested that superoxide and hydroxyl radicals were together responsible for the ssaB mutant's growth defect. We conclude that manganese accumulation mediated by the SsaB transport system imparts virulence by enabling cell growth in oxygen through SodA-dependent and independent mechanisms.


Asunto(s)
Adhesinas Bacterianas/metabolismo , Proteínas Bacterianas/metabolismo , Endocarditis Bacteriana/microbiología , Lipoproteínas/metabolismo , Manganeso/metabolismo , Streptococcus/patogenicidad , Superóxido Dismutasa/metabolismo , Factores de Virulencia/metabolismo , Animales , Modelos Animales de Enfermedad , Técnicas de Inactivación de Genes , Hierro/metabolismo , Lipoproteínas/deficiencia , Conejos , Streptococcus/metabolismo
12.
Metab Eng ; 28: 19-27, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25499652

RESUMEN

Biotechnological production of biofuels is restricted by toxicity of the products such as ethanol and butanol. As its low toxicity to microbes, 2,3-butanediol (2,3-BD), a fuel and platform bio-chemical, could be a promising alternative for biofuel production from renewable bioresources. In addition, no bacterial strains have been reported to produce enantiopure 2,3-BD using lignocellulosic hydrolysates. In this study, Enterobacter cloacae strain SDM was systematically and metabolically engineered to construct an efficient biocatalyst for production of the fuel and enantiopure bio-chemical-(2R,3R)-2,3-BD. First, the various (2R,3R)-2,3-BD dehydrogenase encoding genes were expressed in a meso-2,3-BD dehydrogenase encoding gene disrupted E. cloacae strain under native promoter Pb of the 2,3-BD biosynthetic gene cluster of E. cloacae. Then, carbon catabolite repression was eliminated via inactivation of the glucose transporter encoding gene ptsG and overexpression of a galactose permease encoding gene galP. The resultant strain could utilize glucose and xylose simultaneously. To improve the efficiency of (2R,3R)-2,3-BD production, the byproduct-producing genes (ldh and frdA) were knocked out, thereby enhancing the yield of (2R,3R)-2,3-BD by 16.5% in 500-mL Erlenmeyer flasks. By using fed-batch fermentation in a 5-L bioreactor, 152.0 g/L (2R,3R)-2,3-BD (purity>97.5%) was produced within 44 h with a specific productivity of 3.5 g/[Lh] and a yield of 97.7% from a mixture of glucose and xylose, two major carbohydrate components in lignocellulosic hydrolysates. In addition, when a lignocellulosic hydrolysate was used as the substrate, 119.4 g/L (2R,3R)-2,3-BD (purity>96.0%) was produced within 51 h with a productivity of 2.3g/[Lh] and a yield of 95.0%. These results show that the highest records have been acquired for enantiopure (2R,3R)-2,3-BD production by a native or engineered strain from biomass-derived sugars. In addition to producing the 2,3-BD, our systematic approach might also be used in the production of other important chemicals by using lignocellulose-derived sugars.


Asunto(s)
Proteínas Bacterianas , Biocombustibles , Butileno Glicoles/metabolismo , Lignina/química , Ingeniería Metabólica , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/genética , Enterobacter cloacae/genética , Enterobacter cloacae/metabolismo , Glucosa/química , Glucosa/metabolismo , Xilosa/química , Xilosa/metabolismo
13.
Am J Perinatol ; 32(13): 1205-16, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26007311

RESUMEN

OBJECTIVE: The oral cavity represents an initial entry way for oral and gut indigenous colonization. Skin-to-skin (STS) care, in which the mother holds the diaper clad naked preterm (PT) infant between her breasts, is associated with improved digestive function, decreased stress, and improved survival. This study evaluated the development of oral microbial colonization repertoires and health characteristics in PT infants with or without STS exposure. METHODS: Saliva from 42 PT infants (<32 weeks of gestation at birth) was collected prospectively at 1 month and/or at discharge. High-throughput 16S rRNA sequencing identified microbial diversity and prevalence of bacterial signatures correlated with clinical STS or non-STS care. RESULTS: Corrected for gestational age (CGA) at sampling, bacterial taxa demonstrated increased Streptococcus as a signature of oral repertoire maturation. STS was associated with increased Streptococcus (p < 0.024), while non-STS was associated with greater Corynebacterium (p < 0.023) and Pseudomonas (p < 0.019) in infants ≤ 32 weeks CGA. In infants > 32 weeks CGA, Neisseria and Acinetobacter were more prevalent, 50 vs. 16.7% and 40 vs. 0%, respectively. STS care was associated with shorter hospitalization (p < 0.039). CONCLUSION: STS care during earlier gestation was associated with a distinct microbial pattern and an accelerated pace of oral microbial repertoire maturity.


Asunto(s)
ADN Bacteriano/genética , Método Madre-Canguro/métodos , Microbiota/genética , Boca/microbiología , ARN Ribosómico 16S/genética , Saliva/microbiología , Acinetobacter/genética , Acinetobacter/aislamiento & purificación , Estudios de Casos y Controles , Corynebacterium/genética , Corynebacterium/aislamiento & purificación , Femenino , Edad Gestacional , Humanos , Recien Nacido Extremadamente Prematuro , Recién Nacido , Recien Nacido Prematuro , Masculino , Neisseria/genética , Neisseria/aislamiento & purificación , Pseudomonas/genética , Pseudomonas/aislamiento & purificación , Stenotrophomonas/genética , Stenotrophomonas/aislamiento & purificación , Streptococcus/genética , Streptococcus/aislamiento & purificación
14.
Anal Chem ; 86(19): 9367-71, 2014 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-25196700

RESUMEN

Improving the detection sensitivity of enzyme-linked immunosorbent assay (ELISA) is of utmost importance for meeting the demand of early disease diagnosis. Herein we report an ultrasensitive ELISA system using horseradish peroxidase (HRP)-loaded nanospherical poly(acrylic acid) brushes (SPAABs) as labels. HRP was covalently immobilized in SPAABs with high capacity and activity via an efficient "chemical conjugation after electrostatic entrapment" (CCEE) process, thus endowing SPAABs with high amplification capability as labels. The periphery of SPAAB-HRP was further utilized to bind a layer of antibody with high density for efficient capture of analytes owing to the three-dimensional architecture of SPAABs. Using human chorionic gonadotrophin (hCG) as a model analyte, the SPAAB-amplified system drastically boosted the detection limit of ELISA to 0.012 mIU mL(-1), a 267-fold improvement as compared to conventional ELISA systems.


Asunto(s)
Técnicas Biosensibles , Ensayo de Inmunoadsorción Enzimática/métodos , Peroxidasa de Rábano Silvestre/química , Nanoestructuras/química , Resinas Acrílicas/química , Anticuerpos/química , Gonadotropina Coriónica/sangre , Técnicas Electroquímicas , Enzimas Inmovilizadas , Óxido Ferrosoférrico/química , Humanos , Límite de Detección , Coloración y Etiquetado/métodos , Electricidad Estática
15.
Microbiology (Reading) ; 160(Pt 2): 307-315, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24295823

RESUMEN

Streptococcus sanguinis is a Gram-positive bacterium that is indigenous to the oral cavity. S. sanguinis, a primary colonizer of the oral cavity, serves as a tether for the attachment of other oral pathogens. The colonization of microbes on the tooth surface forms dental plaque, which can lead to the onset of periodontal disease. We examined a comprehensive mutant library to identify genes related to cellular chain length and morphology using phase-contrast microscopy. A number of hypothetical genes related to the cellular chain length were identified in this study. Genes related to the cellular chain length were analysed along with clusters of orthologous groups (COG) for gene functions. It was discovered that the highest proportion of COG functions related to cellular chain length was 'cell division and chromosome separation'. However, different COG functions were also found to be related with altered cellular chain length. This suggested that different genes related with multiple mechanisms contribute to the cellular chain length in S. sanguinis SK36.


Asunto(s)
Streptococcus sanguis/citología , Streptococcus sanguis/genética , Adhesión Bacteriana , División Celular , Segregación Cromosómica , Microscopía de Contraste de Fase , Streptococcus sanguis/fisiología
16.
Bioresour Technol ; 393: 130164, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38072074

RESUMEN

The production and application of biodegradable polylactic acid are still severely hindered by the cost of its polymer-grade lactic acid monomers. High-temperature biomanufacturing has emerged as an increasingly attractive approach to enable low-cost and high-efficiency bulk chemical production. In this study, thermophilic Geobacillus thermoglucosidasius was reprogrammed to obtain optically pure l-lactic acid- and d-lactic acid-producing strains, G. thermoglucosidasius GTD17 and GTD7, by using rational metabolic engineering strategies including pathway construction, by-product elimination, and production enhancing. Moreover, semi-rational adaptive evolution was carried out to further improve their lactic acid synthesis performance. The final strains GTD17-55 and GTD7-144 produce 151.1 g/L of l-lactic acid and 153.1 g/L of d-lactic acid at 60 °C, respectively. In consideration of the high temperature, productive performance of these strains is superior compared to the state-of-the-art industrial strains. This study lays the foundation for the low-cost and efficient production of biodegradable plastic polylactic acid.


Asunto(s)
Bacillaceae , Ingeniería Metabólica , Polímeros , Polímeros/metabolismo , Temperatura , Ácido Láctico , Fermentación
17.
Mol Oral Microbiol ; 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39054378

RESUMEN

Porphyromonas gingivalis is a keystone pathogen in periodontitis, and Streptococcus sanguinis is an abundant oral commensal bacterium associated with periodontal health. However, the interaction between P. gingivalis and S. sanguinis remains obscure. Here, we established a strategy for high-throughput measurement of the cell number of P. gingivalis in the coculture with S. sanguinis by detecting the concentration of hydrogen sulfate. The interaction between P. gingivalis and over 2000 S. sanguinis single-gene mutants was characterized using this strategy, and several interaction-associated genes in S. sanguinis were determined by detecting more P. gingivalis cells in the coculture with matched S. sanguinis mutants. Three S. sanguinis interaction-associated genes were predicted to be responsible for cysteine metabolism, and the supplementation of exogenous L-cysteine promoted the cell number of P. gingivalis in the coculture with S. sanguinis. Thus, exogenous L-cysteine and the compromised cysteine metabolism in S. sanguinis enhanced the growth of P. gingivalis in the existence of S. sanguinis. Additionally, the interaction between P. gingivalis and other Streptococcus spp. was examined, and S. pneumoniae was the only streptococci that had no inhibition on the cell number of P. gingivalis. In total, this study established a new strategy for high-throughput screening of the interaction between Streptococcus and P. gingivalis and discovered a set of genes in S. sanguinis that impacted the interaction. The influence of exogenous L-cysteine on the interaction between P. gingivalis and S. sanguinis in the oral cavity needs further investigation.

18.
Environ Pollut ; 341: 122928, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-37967711

RESUMEN

Natural resistance associated macrophage protein 5 (NRAMP5) is a key transporter for cadmium (Cd) uptake by rice roots; however, the effect of OsNRAMP5 on Cd translocation and redistribution in rice plants remains unknown. In this study, an extremely low Cd-accumulation mutant (lcd1) and wild type (WT) plants were utilized to investigate the effect of OsNRAMP5 mutation on Cd translocation and redistribution via the xylem and phloem and its possible physiological mechanism using field, hydroponic and isotope-labelling experiments. The results showed that OsNRAMP5 mutation reduced xylem and phloem transport of Cd, due to remarkably lower Cd translocation from roots to shoots and from the leaves Ⅰ-Ⅲ to their corresponding nodes, as well as lower Cd concentrations in xylem and phloem sap of lcd1 compared to WT plants. Mutation of OsNRAMP5 reduced Cd translocation from roots to shoots in lcd1 plants by increasing Cd deposition in cellulose of root cell walls and reducing OsHMA2-and OsCCX2-mediated xylem loading of Cd, and the citric acid- and tartaric acid-mediated long-distance xylem transport of Cd. Moreover, OsNRAMP5 mutation inhibited Cd redistribution from flag leaves to nodes and panicles in lcd1 plants by increasing Cd sequestration in cellulose and vacuoles, and decreasing OsLCT1-mediated Cd phloem transport in flag leaves.


Asunto(s)
Cadmio , Oryza , Cadmio/metabolismo , Oryza/genética , Oryza/metabolismo , Floema/metabolismo , Transporte Biológico , Xilema/metabolismo , Mutación , Celulosa/metabolismo , Raíces de Plantas/metabolismo
19.
Int J Biol Macromol ; 259(Pt 2): 128971, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38161011

RESUMEN

In this paper, magnetic composite of lignin/Fe3O4 spheres were synthesized via a straightforward one-step in-situ solvothermal method showing good capacity for adsorbing heavy metal ions and dyes. The physicochemical properties of lignin/Fe3O4 spheres are analyzed using a range of techniques such as SEM, XRD, FTIR, VSM, TG, and BET. Lignin/Fe3O4 spheres exhibited high adsorption capacities of 100.00, 353.36 and 223.71 and 180.18 mg/g for Cu (II), Ni (II) and Cr (VI) metal ions and methylene blue (MB) with equilibrium attained within 60 min. After the recycling experiments, lignin/Fe3O4 spheres still possesses excellent superparamagnetic properties and displays high adsorption capacity. The lignin/Fe3O4 spheres are an efficient and continuous adsorbent to remove heavy metal ions of Cu (II), Ni (II), Cr (VI) and cationic dyes of methylene blue in wastewater, which proves the great potential in practical pollutants treatment applications for water systems.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Lignina , Azul de Metileno , Contaminantes Químicos del Agua/química , Metales Pesados/química , Adsorción , Cationes , Colorantes , Fenómenos Magnéticos , Cinética
20.
J Mater Chem B ; 12(13): 3292-3306, 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38502068

RESUMEN

The regeneration and repair of diabetic wounds, especially those including bacterial infection, have always been difficult and challenging using current treatment. Herein, an effective strategy is reported for constructing glucose-responsive functional hydrogels using nanocomposites as nodes. In fact, tannic acid (TA)-modified ceria nanocomposites (CNPs) and a zinc metal-organic framework (ZIF-8) were employed as nodes. Subsequent crosslinking with 3-acrylamidophenylboronic acid achieved functional nanocomposite-hydrogels (TA@CN gel, TA@ZMG gel) by radical-mediated polymerization. Compared with a simple physically mixed hydrogel system, the mechanical properties of TA@CN gel and TA@ZMG gel are significantly enhanced due to the intervention of the nanocomposite nodes. In addition, this kind of nanocomposite hydrogel can realize the programmed loading of drugs and release of drugs in response to glucose/PH, to coordinate and promote its application in the regeneration and repair of diabetic wounds and infected diabetic wounds. Specifically, TA@CN gel can remove reactive oxygen species and generate oxygen through its various enzymatic activities. At the same time, it can effectively promote neovascularization, thus promoting the regeneration and repair of diabetic wounds. Furthermore, glucose oxidase-loaded TA@ZMG gel exhibits glucose response and pH-regulating functions, triggering programmed metformin (Met) release by degrading the metal-organic framework (MOF) backbone. It also exhibited additional synergistic effects of antibacterial activity, hair regeneration and systemic blood glucose regulation, which make it suitable for the repair of more complex infected diabetic wounds. Overall, this novel nanocomposite-mediated hydrogel holds great potential as a biomaterial for the healing of chronic diabetic wounds, opening up new avenues for further biomedical applications.


Asunto(s)
Diabetes Mellitus , Estructuras Metalorgánicas , Nanocompuestos , Polifenoles , Hidrogeles , Nanogeles , Glucosa
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