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1.
Plants (Basel) ; 13(17)2024 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-39273921

RESUMEN

Invasive alien plants (IAPs) pose a significant threat to island biodiversity and severely impact ecosystems. Understanding the species-area relationship and environmental determinants of growth forms for IAP species on subtropical islands is crucial for establishing an IAP's early warning mechanism, enhancing island ecological management, and protecting the ecosystems of Fujian and other subtropical islands. The study identified significant species-area relationships for IAPs and different life-form plants (trees, shrubs, and herbs), with slopes of 0.27, 0.16, 0.15, and 0.24, respectively. The small island effect does not apply to all species. Isolation has little effect on species richness, and the IAPs on Fujian islands do not conform to the isolation effect in island biogeography. Landscape factors are the main determinants of IAPs and different life-form species richness, with area, shape index, and perimeter-area ratio being the three primary landscape factors. These environmental factors are closely related to habitat heterogeneity. Besides landscape factors, different life forms respond differently to environmental factors. Climate drives the species richness distribution of shrubs and herbs, while trees are mainly influenced by human activities. Overall, landscape, human disturbance, and climate jointly drive the distribution of IAPs, with landscape factors being the most significant.

2.
PLoS One ; 19(6): e0303746, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38848429

RESUMEN

Traditional villages are the common historical and cultural heritage of all mankind. With the intensification of urbanization, the continuation of traditional villages and the inheritance of historical and cultural heritage are facing risks. The research on the driving factors affecting the spatial distribution characteristics, heterogeneity and human land interaction of traditional villages provides a new idea for the protection of traditional villages. This study takes 137 traditional villages in Puxian area, a typical cultural area in the southeast coast, as the research object, analyzes the spatial distribution pattern of traditional villages by using spatial analysis method, and selects 13 factors to analyze the main driving forces and interaction mechanisms through geographical detectors. The results show that: (1) Puxian traditional villages are clustered and distributed, and the distribution among counties is uneven, mainly in the state of "one cluster and many scattered points" with more coastal areas and less mountainous areas. (2) Puxian traditional villages are mainly affected by many factors such as nature, space, society and culture. They are more densely distributed in areas with rich cultural heritage, fertile land, flat terrain, suitable climate, close to water systems, developed transportation, backward economy and dense population. (3) Cultural factors are the primary factors affecting the spatial distribution of traditional villages, the order of driving factors' explanatory power is: intangible cultural heritage (0.5160) > protected cultural relic units (0.3591) > distance from railway (0.3255) > night light remote sensing (0.3179) > elevation (0.3012) > population density (0.2671) > slope (0.2032) > soil type (0.1804) > precipitation (0.1750) > temperature (0.1744) > land use (0.1492) > distance from river (0.0691)>distance from highway (0.0530). The interaction of intangible cultural heritage, protected cultural relic units and distance from the railway is the dominant factor for the spatial differentiation of traditional villages. Among them, the interaction of intangible cultural heritage∩distance from the railway is the strongest, and the q-value is 0.79, which proves that the interpretation ability of the two factor model is much higher than that of the single factor model. The results of this study reflect that traditional villages and nature, space, society and culture are interdependent, so the protection of traditional villages should be adapted to local conditions.


Asunto(s)
Urbanización , China , Humanos , Población Rural , Análisis Espacial , Conservación de los Recursos Naturales
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 315: 124269, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38608561

RESUMEN

A colorimetric immunoassay was built for determination of carcinoembryonic antigen (CEA) based on papain-based colorimetric catalytic sensing system through the use of glucose oxidase (GOx). In the presence of GOx, glucose was catalytically oxidized to produce H2O2. Through the assistance of papain (as a peroxide mimetic enzyme), the signal came from the oxidative color development of 3,3',5,5'-tetramethylbenzidine (TMB, from colorless to blue) catalyzed by the generated H2O2. Herein, a sandwich-type immunoassay was built based on GOx as labels. As the concentration of CEA increased, more GOx-labeled antibodies specifically associate with target, which leaded to more H2O2 generation. Immediately following this, more TMB were oxidized with the addition of papain. Accordingly, the absorbance increased further. As a result, the concentration of CEA is positively correlated with the change in absorbance of the solution. Under optimal conditions, the CEA concentration was linear in the range of 0.05-20.0 ng/mL, and the limit of detection (LOD) reached 37 pg/mL. The papain-based colorimetric immunoassay also exhibited satisfactory repeatability, stability, and selectivity.


Asunto(s)
Antígeno Carcinoembrionario , Colorimetría , Límite de Detección , Papaína , Antígeno Carcinoembrionario/análisis , Colorimetría/métodos , Papaína/metabolismo , Inmunoensayo/métodos , Humanos , Glucosa Oxidasa/química , Glucosa Oxidasa/metabolismo , Peróxido de Hidrógeno/química , Catálisis , Bencidinas/química , Técnicas Biosensibles/métodos , Reproducibilidad de los Resultados
4.
Medicine (Baltimore) ; 103(4): e37029, 2024 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-38277557

RESUMEN

BACKGROUND: This study aimed to systematically evaluate the clinical effectiveness and safety of acupoint herbal patching in the treatment of postherpetic neuralgia. METHODS: Eight databases including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wan-Fang Database, China Biomedical Literature Service System, and Chongqing VIP Chinese Science were searched. The search time was set to October 2023. Two researchers independently screened the literature according to the inclusion and exclusion criteria; extracted the basic information, acupoints, Chinese herbal medicine, pain score, sleep score, depression score, and other information of the subjects, and independently assessed the risk of bias by 2 researchers. Meta-analysis of the included studies was performed using the StataMP 16 software. RESULTS: Fifteen studies with 1362 participants were included in this meta-analysis. Ashi is the acupoint frequency at the forefront, and Borneol is the Chinese herbal medicine frequency at the forefront. The acupoint herbal patching group showed significant improvements in visual analog score (SMD: -2.09; 95% Cl: -2.77, -1.42; P < .001), sleep score (SMD: -1.58; 95% Cl: -2.11, -1.05; P < .001), depression score (SMD: -1.61; 95% Cl: -2.22, -0.99; P < .001), Chinese medicine syndrome score (SMD: -2.32; 95% Cl: -2.84, -1.80; P = .06), dermatology life quality index (weighted mean differences: -4.11; 95% Cl: -4.58, -3.63; P = .98), and related laboratory indicators compared to the control group, and the total effective rate was significantly higher (relative risk: 1.20; 95% confidence interval: 1.15, 1.26; P = .99) than the control group. Two studies reported adverse reactions, but the 2 groups were not statistically significant. CONCLUSIONS: Acupoint herbal patching intervention in postherpetic neuralgia is effective in improving the pain, sleep, anxiety, depression, quality of life of patients, and related laboratory indicators.


Asunto(s)
Medicamentos Herbarios Chinos , Neuralgia Posherpética , Humanos , Medicamentos Herbarios Chinos/uso terapéutico , Neuralgia Posherpética/tratamiento farmacológico , Puntos de Acupuntura , Calidad de Vida , Fitoterapia
5.
Int J Biol Macromol ; 258(Pt 2): 128922, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38141699

RESUMEN

Burkholderia pseudomallei, an intracellular pathogen, is responsible for melioidosis, a zoonotic disease. Its pathogenesis involves several virulence factors, among which lipopolysaccharide (LPS) plays a crucial role. Our research reveals that the O antigen present within the LPS significantly regulates the host immune response. In a previous study, we obtained a B. pseudomallei mutant strain ΔwbiI. Here, the purification of LPS from ΔwbiI and a gas chromatography-mass spectrometry (GC-MS) analysis were conducted. The results confirmed the absence of specific sugar 6-deoxy-Talp, which is a typical component of the O antigen in the wild type B. pseudomallei. Our findings underscore the potent impact the O antigen exerts on the virulence of B. pseudomallei. The ΔwbiI strain displayed significantly increased invasiveness and cytotoxicity in vitro. This enhanced cytotoxicity seems to be related to the exposure of lipid A and an increased cell membrane hydrophobicity resulting from the deletion of the O antigen. Additionally, in mouse models, the ΔwbiI strain resulted in a heightened host lethality and an excessive inflammatory response in mice. These findings indicate that the O-antigenic polysaccharide moiety of B. pseudomallei plays a role in its pathogenicity in vitro and in vivo.


Asunto(s)
Burkholderia pseudomallei , Ratones , Animales , Antígenos O/genética , Lipopolisacáridos , Virulencia , Mutación
6.
Heliyon ; 9(9): e20012, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37809632

RESUMEN

Shiga toxin type 2 (Stx2) is the primary virulence factor produced by Shiga toxin-producing enterohemorrhagic Escherichia coli (STEC), which causes epidemic outbreaks of gastrointestinal sickness and potentially fatal sequela hemolytic uremic syndrome (HUS). Most studies on Stx2-induced apoptosis have been performed with holotoxins, but the mechanism of how the A and B subunits of Stx2 cause apoptosis in cells is not clear. Here, we found that Stx2 A-subunit (Stx2A) induced mitochondrial damage, PINK1/Parkin-dependent mitophagy and apoptosis in Caco-2 cells. PINK1/Parkin-dependent mitophagy caused by Stx2A reduced apoptosis by decreasing the accumulation of reactive oxidative species (ROS). Mechanistically, Stx2A interacts with Tom20 on mitochondria to initiate the translocation of Bax to mitochondria, leading to mitochondrial damage and apoptosis. Overall, these data suggested that Stx2A induces mitochondrial damage, mitophagy and apoptosis via the interaction of Tom20 in Caco-2 cells and that mitophagy caused by Stx2A ameliorates apoptosis by eliminating damaged mitochondria. These findings provide evidence for the potential use of Tom20 inhibition as an anti-Shiga toxin therapy.

7.
Carbohydr Polym ; 318: 121105, 2023 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-37479434

RESUMEN

Intake of foods upon thermal treatment is typically associated with an elevated postprandial glycemic response, which is one of the risk factors for type 2 diabetes development and progression. In this study, rice starch was thermally treated using aqueous phase (boil), air phase (bake), and lipid phase (fry). Peak blood glucose levels in C57 mice increased by 16.94 %, 12.60 %, and 8.1 % after ingestion of thermally treated starch (20.23, 19.48, and 18.70 mmol/L), compared with raw starch (17.30 mmol/L). The insulin response to the intake of thermally treated starch increased (4.73 %-6.83 % higher than the control), whereas the concentration of GLP-1, a hormone used to promote insulin secretion, decreased (1.54 %-8.56 % lower than the control). Furthermore, thermally treated starch accelerated food absorption by enhancing gastrointestinal digestion, exacerbating postprandial glucose fluctuation at the next meal. Structural characterization showed thermal treatment reduced starch branching density and degree of structure order, which were not conducive to preventing the attack of enzymes. During digestion, they were highly hydrolyzed into low-molecular-weight fragments, and the proportion of ultrashort chains substantially increased. These findings provide a better understanding of the fine structure of starch that promotes hypoglycemia and initially explain how diets high in thermally treated starch impair glucose balance.


Asunto(s)
Diabetes Mellitus Tipo 2 , Animales , Ratones , Alimentos , Glucosa , Almidón , Digestión
8.
iScience ; 26(5): 106770, 2023 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-37216106

RESUMEN

Persistent Fusobacterium nucleatum infection is associated with the development of human colorectal cancer (CRC) and promotes tumorigenicity, but the underlying mechanisms remain unclear. Here, we reported that F. nucleatum promoted the tumorigenicity of CRC, which was associated with F. nucleatum-induced microRNA-31 (miR-31) expression in CRC tissues and cells. F. nucleatum infection inhibited autophagic flux by miR-31 through inhibiting syntaxin-12 (STX12) and was associated with the increased intracellular survival of F. nucleatum. Overexpression of miR-31 in CRC cells promoted their tumorigenicity by targeting eukaryotic initiation factor 4F-binding protein 1/2 (eIF4EBP1/2), whereas miR-31 knockout mice were resistant to the formation of colorectal tumors. In conclusion, F. nucleatum, miR-31, and STX12 form a closed loop in the autophagy pathway, and continuous F. nucleatum-induced miR-31 expression promotes the tumorigenicity of CRC cells by targeting eIF4EBP1/2. These findings reveal miR-31 as a potential diagnostic biomarker and therapeutic target in CRC patients with F. nucleatum infection.

9.
Anal Chim Acta ; 1252: 341059, 2023 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-36935157

RESUMEN

Burkholderia pseudomallei is the causative agent of melioidosis, a potentially life-threatening infectious disease, and poses public health risks in endemic areas. Due to the high mortality, intrinsic antibiotic resistance, and atypical manifestations, establishing a rapid, accurate, and sensitive identification of B. pseudomallei enables earlier diagnosis, proper treatments, and better outcomes of melioidosis. Herein, we present a One-Pot CRISPR-integrated assay for Instant and Visual Detection (termed OPC-IVD) of B. pseudomallei. The integration of recombinase polymerase amplification and CRISPR-Cas12a recognition-activated trans-cleavage, achieved a true all-in-one single-tube reaction system, initiating the amplification and cleavage simultaneously, which realized a facile sample-to-answer assay. This approach could be performed with simplified DNA extraction and completed around 30 min by holding the reaction tube in the hand. The detection limit of our OPC-IVD was determined to be 2.19 copy/uL of plasmid DNA, 12.5 CFU/mL of B. pseudomallei, and 61.5 CFU/mL of bacteria in spiked blood samples, respectively. Furthermore, the introduction of internal amplification control effectively reduced the occurrence of false negatives, which was incorporated in the reaction system, and amplified simultaneously with the target and read by naked eyes. The assay exhibited 100% accuracy when evaluated in clinical isolates and samples. The streamlined workflow of our OPC-IVD of B. pseudomallei enables a field-deployable, instrument-free, and ultra-fast approach that can be utilized by non-expert personnel in the field of molecular diagnosis of melioidosis especially in under-resourced setting.


Asunto(s)
Burkholderia pseudomallei , Melioidosis , Humanos , Burkholderia pseudomallei/genética , Melioidosis/diagnóstico , Melioidosis/genética , Melioidosis/microbiología , Sistemas CRISPR-Cas
10.
Int J Biol Macromol ; 230: 123130, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36610573

RESUMEN

In this study, rice starch-protein hydrolysate (WPH-S) complexes with high resistant starch (RS) content were prepared by heat-moisture treatment (HMT) and annealing (ANN). The effects of different hydrothermal treatments on the structure and thermal stability of the WPH-S complexes and their relationship with starch digestibility were further discussed. The results showed that RS contents of ANN-WPH-S complexes (35.09-40.26 g/100 g) were higher than that of HMT-WPH-S complexes (24.15-38.74 g/100 g). Under hydrothermal treatments, WPH decreased the hydrolysis kinetic constant (k) of starch form 4.07 × 10-2-4.63 × 10-2 min-1 to 3.29 × 10-2-3.67 × 10-2 min-1. HMT and ANN promoted hydrogen bonding between WPH and starch molecules, thus increasing the molecular size of starch. In addition, the shear stability of WPH-S mixture was improved with the hysteresis loop area decreased after HMT/ANN treatments, resulting in a more stable structure. Most importantly, the hydrothermal treatment made the scatterers of WPH-S complexes denser and the surface smoother. Especially after ANN treatment, the WPH60-S complex formed a denser aggregate structure, which hindered the in vitro digestion of starch to a certain extent. These results enrich our understanding of the regulation of starch digestion by protein hydrolysates under different hydrothermal treatments and have guiding significance for the development of foods with a low glycemic index.


Asunto(s)
Oryza , Hidrolisados de Proteína , Oryza/química , Almidón/química , Hidrólisis , Almidón Resistente , Calor , Digestión
11.
Food Chem ; 408: 135153, 2023 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-36527925

RESUMEN

Wheat protein hydrolysates (WPH) were prepared by pepsin hydrolysis for 30, 60, and 120 min (WPH30, WPH60, and WPH120). The mixed system of rice starch and WPH was hydrothermally treated to explore the effect of WPH with different degrees of hydrolysis on starch digestion. WPH reduced the first-order rate coefficient (k) of starch digestion. Especially, WPH30 reduced the k value the most and formed the highest slowly digestible starch content due to the entanglement of starch chains and long-chain peptides. WPH60 and WPH120 with more hydrophobic peptides and polar amino acids than WPH30 tended to form hydrogen bonds with starch molecules due to less steric hindrance. Particularly, the complexation of WPH60 promoted the formation of dense aggregate structure and hindered the enzymatic hydrolysis of starch to a certain extent, thereby increasing the resistant starch content. These findings provide significant guidance for the preparation of hypoglycemic reformed food.


Asunto(s)
Almidón , Triticum , Almidón/química , Hidrólisis , Triticum/química , Hidrolisados de Proteína/metabolismo , Digestión
12.
Cancer Sci ; 113(11): 3787-3800, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35984699

RESUMEN

Fusobacterium nucleatum infection plays vital roles in colorectal cancer (CRC) progression. Overexpression of microRNA-4717-3p (miR-4717) was reported to be upregulated in F. nucleatum positive CRC tissues, however, the underlying mechanism is unknown. In this study, we found that miR-4717 promoted CRC cell proliferation in vitro and growth of CRC in vivo following F. nucleatum infection. MicroRNA-4717 suppressed the expression of mitogen-activated protein kinase kinase 4 (MAP2K4), a tumor suppressor, by directly targeting its 3'-UTR. Furthermore, we confirmed that methyltransferase-like 3 (METTL3)-dependent m6 A methylation could methylate primary (pri)-miR-4717, which further promoted the maturation of pri-miR-4717, and METTL3 positively regulated CRC cell proliferation through miR-4717/MAP2K4 pathways. In conclusion, F. nucleatum-induced miR-4717 excessive maturation through METTL3-dependent m6 A modification promotes CRC cell proliferation, which provides a potential therapeutic target and diagnostic biomarker for CRC.


Asunto(s)
Neoplasias Colorrectales , MicroARNs , Humanos , Fusobacterium nucleatum/genética , MicroARNs/genética , MicroARNs/metabolismo , Neoplasias Colorrectales/patología , Proliferación Celular/genética , Regiones no Traducidas 3' , Metiltransferasas/genética
13.
NPJ Sci Food ; 6(1): 37, 2022 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-36008427

RESUMEN

Clarifying the interactions between food components is critical in designing carbohydrate-based foods with low digestibility. To date, the hindering effect of starch-protein interactions on starch digestion has attracted extensive attention. In this study, rice proteins were further hydrolyzed, and rice peptides (RP) with different molecular weights were obtained by ultrafiltration. The effects and possible mechanisms of RP with different molecular weights on the structure, thermal properties, and in vitro digestibility of cooked rice starch were investigated. All peptides slowed the digestion of rice starch in a concentration-dependent manner. A concentration of 10% RP>10 decreased the rapidly digestible starch content from 68.02 to 45.90 g/100 g, and increased the resistant starch content from 17.54 to 36.54 g/100 g. The addition of RP improved the thermal stability of the starch and reduced the amount of leached amylose. Infrared analysis shows that strong hydrogen bonds formed between RP (especially RP>10) and starch during co-gelatinization. In addition, RP improved the compactness of aggregated structure and played an important role in hindering the enzymatic hydrolysis of starch. These results enrich the theory of starch-protein interactions and have important implications for the development of carbohydrate-based foods with low digestibility and protein functional foods.

14.
Cell Rep ; 40(3): 111127, 2022 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-35858553

RESUMEN

Both Fusobacterium nucleatum (F. nucleatum) and long non-coding RNA (lncRNA) EVADR are associated with colorectal cancer (CRC), but their relationship with CRC metastasis and the mechanisms by which EVADR promotes CRC metastasis are poorly understood. Here, we report that F. nucleatum promotes colorectal cancer cell metastasis to the liver and lung and that it can be detected in CRC-metastasis colonization in mouse models. Furthermore, F. nucleatum upregulates the expression of EVADR, which can increase the metastatic ability of CRC cells in vivo and in vitro. Mechanistically, elevated EVADR serves as a modular scaffold for the Y-box binding protein 1 (YBX1) to directly enhance the translation of epithelial-mesenchymal transition (EMT)-related factors, such as Snail, Slug, and Zeb1. These findings suggest that EVADR induced by F. nucleatum promotes colorectal cancer metastasis through YBX1-dependent translation. The EVADR-YBX1 axis may be useful for the prevention and treatment of patients with F. nucleatum-associated CRC metastasis.


Asunto(s)
Neoplasias Colorrectales , Infecciones por Fusobacterium , ARN Largo no Codificante , Animales , Carcinogénesis/genética , Neoplasias Colorrectales/patología , Infecciones por Fusobacterium/complicaciones , Infecciones por Fusobacterium/microbiología , Infecciones por Fusobacterium/patología , Fusobacterium nucleatum/genética , Ratones , ARN Largo no Codificante/genética
15.
Eur J Emerg Med ; 29(2): 105-117, 2022 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-34619690

RESUMEN

This meta-analysis aimed to assess the diagnostic accuracy of lung ultrasonography in pneumonia-affected pediatric patients. Literature search of published articles in Medline, Web of Science, Scopus, Embase and Journal of Web till September 2020 were reviewed for the predescribed accuracy assessors. In compliance with the inclusion and exclusion criteria, two researchers independently screened the literature, collected the results and assessed the risks of bias using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. The pooled sensitivity and specificity, pooled positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were estimated for the meta-analysis. The overall efficiency of lung ultrasonography (LUS) was evaluated using a summary receiver operating characteristic curve. Q and I2 statistics were used to determine heterogeneity. Meta disc software was used for the analysis of the study. Out of 1182 studies, only 29 articles were chosen; 25 of them were prospective studies and 4 studies were retrospective. The overall pooled sensitivity was 0.83 [95% confidence intervals (CI), 0.81-0.84] and specificity was 0.84 (95% CI, 0.81-0.86), depicting good diagnostic performance. LUS is an efficient imaging technique for detecting childhood pneumonia with a high accuracy rate. It is an appealing alternative to chest X rays to detect and follow-up pneumonia in children because it is simple to do, widely available, comparatively cheap and free of radiation hazards.


Asunto(s)
Neumonía , Niño , Humanos , Pulmón/diagnóstico por imagen , Neumonía/diagnóstico por imagen , Estudios Prospectivos , Estudios Retrospectivos , Sensibilidad y Especificidad , Ultrasonografía
16.
Int J Biol Macromol ; 195: 483-491, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34920068

RESUMEN

Non-crystalline granular starch (NCGS) has advantages in the deep processing of starch owing to its unique structure and function. In this study, NCGS was successfully prepared at a baking temperature of 210 °C, and the morphology, structure, pasting properties, and rheological properties of the NCGS were systematically studied. Compared with native starch, NCGS showed a lower processing viscosity and rapid reduction in the peak viscosity from 3795 to 147 cP. Furthermore, NCGS exhibited impaired short- and long-range ordered structures, as indicated by the lower ratio of absorbance at 1047/1015 cm-1 and decreased crystallinity compared to native starch. Additionally, amylose and amylopectin with long and medium chains in NCGS were degraded into short chains, resulting in an increase in amylose content and branch density. The analysis of the physicochemical properties of NCGS, especially the low processing viscosity, is of great importance for the industrial application of starch, particularly in terms of improving the yield, saving energy, and reducing environmental pollution.


Asunto(s)
Fenómenos Químicos , Almidón/química , Almidón/aislamiento & purificación , Viscosidad , Reología , Análisis Espectral , Almidón/ultraestructura , Temperatura
17.
Int J Biol Macromol ; 193(Pt A): 311-318, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34699891

RESUMEN

The role of endogenous/exogenous rice protein and its hydrolysates in the enzymatic hydrolysis resistance of rice starch was investigated. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and Fourier transform infrared spectroscopy (FTIR) results showed that different types of rice endogenous proteins retarded the digestion of rice starch by the same way. Exogenous addition of protein hydrolysates was more effective than protein for impeding starch digestion. FTIR results indicated that rice protein hydrolysates were bound to starch granules through hydrogen bonds, and their interaction strengthened the ordered structure of the starch. Further, the intensity of the starch V- type peak was enhanced after the addition of protein hydrolysates, indicating that some peptides or free amino acids released by the protein formed complexes with the starch, thereby contributing to high slowly-digestible starch content. These findings provide a theoretical basis for the preparation of low glycemic index starch-based foods.


Asunto(s)
Oryza/metabolismo , Proteínas de Plantas/metabolismo , Almidón/metabolismo , Digestión , Índice Glucémico , Hidrólisis
18.
Protein Expr Purif ; 174: 105679, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32534017

RESUMEN

The applications of viral protein cages have expanded rapidly into the fields of bionanotechnology and materials science. However, the low-cost production of viral capsid proteins (CPs) on a large scale is always a challenge. Herein, we develop a highly efficient expression system by constructing recombinant Pichia pastoris cells as a "factory" for the secretion of soluble cowpea chlorotic mottle virus (CCMV) CPs. Under optimal induction conditions (0.9 mg/mL of methanol concentration at 30 °C for 96 h), a high yield of approximately 95 mg/L of CCMV CPs was harvested from the fermentation supernatant with CPs purity >90%, which has significantly simplified the rest of the purification process. The resultant CPs are employed to encapsulate Ruthenium (Ru) nanoparticles (NPs) via in-vitro self-assembly to prepare hybrid nanocatalyst, i.e. Ru@virus-like particles (VLPs). The catalytic activity over Ru@VLPs was evaluated by reducing 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The results indicate that, with the protection of protein cages, Ru NPs were highly stabilized during the catalytic reaction. This results in enhanced catalytic activity (reaction rate constant k = 0.14 min-1) in comparison with unsupported citrate-stabilized Ru NPs (Ru-CA) (k = 0.08 min-1). Additionally, comparatively lower activation energy over Ru@VLPs (approximately 32 kJ/mol) than that over Ru-CA (approximately 39 kJ/mol) could be attributed to the synergistic effect between Ru NPs and some functional groups such as amino groups (-NH2) on CPs that weakened the activation barrier of 4-NP reduction. Therefore, enhanced activity and decreased activation energy over Ru@VLPs demonstrated the superiority of Ru@VLPs to unsupported Ru-CA.


Asunto(s)
Bromovirus/genética , Proteínas de la Cápside , Nanopartículas del Metal/química , Rutenio/química , Saccharomycetales , Proteínas de la Cápside/biosíntesis , Proteínas de la Cápside/química , Proteínas de la Cápside/genética , Proteínas de la Cápside/aislamiento & purificación , Cápsulas , Catálisis , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Saccharomycetales/genética , Saccharomycetales/crecimiento & desarrollo
19.
Catal Letters ; 150(12): 3542-3552, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32421047

RESUMEN

ABSTRACT: In this work, a new viral protein cage based nanoreactor was successfully constructed via encapsulating Tween 80 stabilized palladium nanoparticles (NPs) into rotavirus capsid VP2 virus-like particles (i.e. Pd@VP2). The effects of stabilizers including CTAB, SDS, Tween 80 and PVP on controlling the particle size of Pd NPs were investigated. They were further immobilized on graphene oxide (i.e. Pd@VP2/GO) by a simple mixing method. Some characterizations including FT-IR and XPS were conducted to study adsorption mode of Pd@VP2 on GO sheets. Their catalytic performance was estimated in the reduction of 4-nitrophenol (4-NP). Results showed that Tween 80 stabilized Pd NPs with the molar ratio of Pd to Tween 80 at 1:0.1 possessed the smallest size and the best stability as well. They were encapsulated into viral protein cages (mean size 49 ± 0.26 nm) to assemble confined nanoreactors, most of which contained 1-2 Pd NPs (mean size 8.15 ± 0.26 nm). As-prepared Pd@VP2 indicated an enhanced activity (apparent reaction rate constant k app = (3.74 ± 0.10) × 10-3 s-1) for the reduction of 4-NP in comparison to non-confined Pd-Tween80 colloid (k app = (2.20 ± 0.06) × 10-3 s-1). It was logically due to confinement effects of Pd@VP2 including high dispersion of Pd NPs and high effective concentration of substrates in confined space. Pd@VP2 were further immobilized on GO surface through C-N bond. Pd@VP2/GO exhibited good reusability after recycling for four runs, confirming the strong anchoring effects of GO on Pd@VP2.

20.
Int J Biol Macromol ; 146: 620-626, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-31923494

RESUMEN

The pasting and rheological properties of waxy rice powder (WRP) with high-temperature baking (140-180 °C) and the fine structure of its starch were investigated. Rapid visco-analysis showed that the viscosity and breakdown value of baked WRP decreased obviously compared to its native counterpart, and this trend was greatly increased under higher temperature. Rheological analysis indicated that the baked WRP had relatively more elastic component compared to viscosity component but was less thixotropic than native WRP, suggesting the swelling of starch granules and the leaching of starch molecules were retarded when the WRP was baked at high temperature. Additionally, WRP was severely degraded and further re-associated and interacted with other granules during high-temperature baking. Changes in starch fine structure contributed to the alteration of pasting and rheological properties of WRP. These findings suggest that high-temperature baking induced structural changes of starch and thus reduced the viscosity of WRP.


Asunto(s)
Calor , Oryza/química , Reología , Almidón/química , Ceras/química , Elasticidad , Peso Molecular , Tamaño de la Partícula , Polvos/química , Viscosidad
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