Influence of D-Amino Acids in Beer on Formation of Uric Acid

Prekomjerna konzumacija piva može dovesti do povećanja koncentracije mokraćne kiseline u serumu, čime se povećava rizik nastanka uričnog artritisa (gihta), što se prethodno dovodilo u vezu s velikim udjelom purina u pivu. Međutim, novija istraživanja pokazuju da konzumacija povrća bogatog purinima i grahorica ne povećava koncentraciju mokraćne kiseline, što opovrgava tu tvrdnju. Još uvijek nije objašnjeno zašto povećana konzumacija piva može povećati rizik nastanka gihta, pa su ispitani drugi uzročnici nakupljanja mokraćne kiseline u krvi. Pivo sadržava relativno velike koncentracije D-aminokiselina koje nastaju racemizacijom L-aminokiselina tijekom prerade hrane. Katalizom pomoću D-aminokiselinske oksidaze iz D-aminokiselina nastaje H2O2, čijom oksidacijom u prisutnosti Fe2+ nastaju hidroksilni radikali. Pritom dolazi do oštećenja DNA i nastanka purinskih baza u većoj količini, iz kojih djelovanjem različitih enzima nastaje mokraćna kiselina. Neki dodaci hrani, kao što su vitamini i ioni joda, potiču nastanak mokraćne kiseline iz D-aminokiselina. D-aminokiseline u pivu imaju ključnu ulogu u povećanju koncentracije mokraćne kiseline. Biološka uloga D-aminokiselina može objasniti pojavu gihta kod osoba koje učestalo konzumiraju pivo.Excessive intake of beer could increase serum uric acid levels, leading to high risk of gout, which was previously attributed to high purine content in beer. Recent reports that purine-rich vegetables and bean products do not cause higher uric acid levels do not support this theory. Why excessive intake of beer could increase a high risk of gout has been unclear. Other factors affecting the accumulation of uric acid in the blood have been explored. Beer contains relatively high levels of D-amino acids due to the racemization of l-amino acids induced by food processing. D-amino acid was catalyzed by D-amino acid oxidase to produce H2O2, which is further oxidized in the presence of Fe2+ to produce hydroxyl radicals, resulting in DNA damage and formation of a large amount of purine bases, which are oxidized to uric acid by a series of enzymes. Some food ingredients, such as vitamins and I–, prompt D-amino acids to form uric acid. D-amino acids in beer are one of the key factors responsible for the increase in uric acid levels. The biological response of D-amino acids could explain gout occurrence in beer drinkers

Phytochemical compositions, antioxidant and antimicrobial activities analysis of extracts from <i>Vaccinium bracteatum</i> Thunb. leaves

Vaccinium bracteatum Thunb. is an edible plant, which has been used for many food products and is also a resource of traditional Chinese medicine. In this study, the antioxidant and antimicrobial activities of ethanol extracts from its leaves were investigated. To study the characteristic compositions, twelve compounds of extracts accumulated by the D-101 macroporous adsorption resin (VBE) were identified by HPLC-DAD and HPLC-ESI/MS techniques, including chlorogenic acid and its isomers, and eight flavonoid compounds. The contents of total flavonoids, orientin and isoorientin in the accumulated part were 601.4, 44.7, and 96.1 mg/g, respectively, which were far more than that in the raw materials. Furthermore, the antioxidant activities were estimated by DPPH, ABTS, and FRAP assays, which showed that the high content accompanied with strong antioxidant activities. Besides, compared to the same type of bamboo leaves (AOB), the accumulated part possesses better activities. At the last, the antimicrobial activities of VBE were assessed by a serial two-fold dilution assay, the results showed that it had good antimicrobial activities. Taken together, extracts from Vaccinium bracteaturn Thunb. leaves have better antioxidant activities, which can be used as a natural antioxidant

Data for transcriptomic and proteomic analyses of leaves from Clematis terniflora DC. under binary stress

High level of UV-B irradiation followed by dark treatment accumulates secondary metabolites in Clematis terniflora DC. To investigate the response mechanism under high level of UV-B irradiation followed by dark treatment, transcriptomic and proteomic analyses were performed in leaves of Clematis terniflora DC. The experimental design for the transcriptomic and proteomic analyses in leaves of C. terniflora under stresses was organized into a picture. For transcriptomics, mRNA-sequencing technology was used. Genes identified in leaves of C. terniflora at starting point, high level of UV-B irradiation, and high level of UV-B irradiation followed by dark treatment were listed; genes with different expression levels at starting point, high level of UV-B irradiation, and high level of UV-B irradiation followed by dark treatment were also presented in this DiB article. For proteomics, a gel-free/label-free proteomic technique was used. Proteins with different abundances in leaves at starting point, high level of UV-B irradiation, and high level of UV-B irradiation followed by dark treatment were presented in this DiB article. In order to monitor the expression levels of genes under the stress, quantitative reverse transcription polymerase chain reaction was performed. The primer sequences of genes selected for quantitative reverse transcription polymerase chain reaction was presented in this DiB article

A New Empirical Model of Weighted Mean Temperature Combining ERA5 Reanalysis Data, Radiosonde Data, and TanDEM-X 90m Products over China

Weighted mean temperature (Tm) is an important parameter in the water vapor inversion of global navigation satellite systems (GNSS). High-precision Tm values can effectively improve the accuracy of GNSS precipitable water vapor. In this study, a new regional grid Tm empirical model called the RGTm model over China and the surrounding areas was proposed by combining ERA5 reanalysis data, radiosonde data, and TanDEM-X 90m products. In the process of model establishment, we considered the setting of the reference height in the height correction formula and the bias correction for the Tm lapse rate. Tm values derived from ERA5 and radiosonde data in 2019 were used as references to validate the performance of the RGTm model. At the same time, the GPT3, GGNTm, and uncorrected seasonal model were used for comparison. Results show that compared with the other three models, the accuracy of the RGTm model’s Tm was improved by approximately 12.21% (15.32%), 1.17% (3.09%), and 2.31% (5.05%), respectively, when ERA5 (radiosonde) Tm data were used as references. In addition, the introduction of radiosonde data prevented the accuracy of the Tm empirical model from being entirely dependent on the accuracy of the reanalysis data

Liquid single-electrode triboelectric nanogenerator based on graphene oxide dispersion for wearable electronics

Owing to the limited deformability and restricted scalability of traditional triboelectric nanogenerator (TENG), liquid single-electrode TENG based on graphene oxide dispersion (GO LS-TENG) was developed in this study. The device exhibits high short-circuit current density of 18.61 mA m(-2) at contact frequency of 3 Hz, being much higher than that of reported LS-TENG based on NaCl solution (1.8 mA m(-2), 2.3 Hz) and liquid metal (8.6 mA m(-2), 3 Hz). Moreover, its maximum power density can reach 4.97 W m(-2) (1.99 mW, 3 Hz), which is higher than that of a reported single-electrode TENG based on GO solid electrode (3.13 W m(-2), 5 Hz). On palm tapping the device, 87 green LEDs connected in series can be lit up. Robustness, durability and reproducibility tests show high stability, sensitivity, and potential use of this device in wearable electronics. This work demonstrates a novel approach to fabricate LS-TENG with simple structure, high output and high sensitivity for use in highly flexible and deformable wearable devices