GmMYB114 Facilitates the Synthesis of Anthocyanins in Soybean Sprouts under Blue Light.

Soybean sprouts constitute a significant segment of the vegetable market due to their nutritional richness, particularly in various flavonoids, which contribute to numerous health benefits. The augmentation of the flavonoid content in soybean sprouts is pivotal for enhancing their economic value. While research has established the potential of blue light in promoting the synthesis of anthocyanins, a subclass of flavonoids known for their health advantages, the precise regulatory mechanisms remain elusive. In this study, we identified a notable upregulation of an R2R3 type MYB transcription factor, GmMYB114, in response to blue light exposure, exhibiting a significant positive correlation with anthocyanin accumulation in soybean sprouts. The functional role of GmMYB114 was validated in soybean hairy roots, wherein its overexpression substantially augmented anthocyanin synthesis. Further investigations employing yeast one-hybrid (Y1H), dual-luciferase reporter (LUC), and GUS assays revealed that GmMYB114 indirectly influences anthocyanin synthesis as it does not directly bind to the promoters of anthocyanin synthesis genes to activate their expression. These findings contribute to elucidating the mechanism underlying blue light-mediated enhancement of anthocyanin synthesis in soybean sprouts, offering valuable insights for harnessing molecular technologies to obtain anthocyanin-enriched soybean sprouts.

Blue Light Enhances Health-Promoting Sulforaphane Accumulation in Broccoli (Brassica oleracea var. italica) Sprouts through Inhibiting Salicylic Acid Synthesis.

As a vegetable with high nutritional value, broccoli (Brassica oleracea var. italica) is rich in vitamins, antioxidants and anti-cancer compounds. Glucosinolates (GLs) are one of the important functional components widely found in cruciferous vegetables, and their hydrolysate sulforaphane (SFN) plays a key function in the anti-cancer process. Herein, we revealed that blue light significantly induced the SFN content in broccoli sprouts, and salicylic acid (SA) was involved in this process. We investigated the molecular mechanisms of SFN accumulation with blue light treatment in broccoli sprouts and the relationship between SFN and SA. The results showed that the SFN accumulation in broccoli sprouts was significantly increased under blue light illumination, and the expression of SFN synthesis-related genes was particularly up-regulated by SA under blue light. Moreover, blue light considerably decreased the SA content compared with white light, and this decrease was more suppressed by paclobutrazol (Pac, an inhibitor of SA synthesis). In addition, the transcript level of SFN synthesis-related genes and the activity of myrosinase (MYR) paralleled the trend of SFN accumulation under blue light treatment. Overall, we concluded that SA participates in the SFN accumulation in broccoli sprouts under blue light.

Automatic Multilabel Classification of Multiple Fundus Diseases Based on Convolutional Neural Network With Squeeze-and-Excitation Attention.

Purpose: Automatic multilabel classification of multiple fundus diseases is of importance for ophthalmologists. This study aims to design an effective multilabel classification model that can automatically classify multiple fundus diseases based on color fundus images. Methods: We proposed a multilabel fundus disease classification model based on a convolutional neural network to classify normal and seven categories of common fundus diseases. Specifically, an attention mechanism was introduced into the network to further extract information features from color fundus images. The fundus images with eight categories of labels were applied to train, validate, and test our model. We employed the validation accuracy, area under the receiver operating characteristic curve (AUC), and F1-score as performance metrics to evaluate our model. Results: Our proposed model achieved better performance with a validation accuracy of 94.27%, an AUC of 85.80%, and an F1-score of 86.08%, compared to two state-of-the-art models. Most important, the number of training parameters has dramatically dropped by three and eight times compared to the two state-of-the-art models. Conclusions: This model can automatically classify multiple fundus diseases with not only excellent accuracy, AUC, and F1-score but also significantly fewer training parameters and lower computational cost, providing a reliable assistant in clinical screening. Translational Relevance: The proposed model can be widely applied in large-scale multiple fundus disease screening, helping to create more efficient diagnostics in primary care settings.

Spectroscopic, kinetic, and theoretical analyses of oxidation of dl-ethionine by Pt(IV) anticancer model compounds.

Ethionine is an S-ethyl analog of methionine (Met) having a small change in structure. But it is a chemical carcinogen and an antagonist of Met, thus displaying a disparate biological profile. The oxidations of ethionine by biologically important oxidants have not been exploited. Oxidations of dl-ethionine by Pt(IV) anticancer model complexes trans-[PtX2(CN4)]2- (X = Cl or Br) were thus analyzed by time-resolved and stopped-flow spectral techniques. Overall second-order kinetics was established, being first-order in [Pt(IV)] and [Ethionine]tot (the total concentration of ethionine); the observed second-order rate constant k' versus pH profiles were obtained. A stoichiometry of Δ[Pt(IV)]:Δ[Ethionine]tot = 1:1 was unraveled, indicating that ethionine was oxidized to ethionine-sulfoxide which was confirmed by NMR spectroscopic and high-resolution mass spectral analyses. In the proposed reaction mechanism which is similar to that for the oxidation of Met by the same Pt(IV) compounds, the rate-determining steps are rationalized in terms of a bridge formation between one of the coordinated halides in [PtX2(CN4)]2- and the sulfur atom in ethionine, followed by an X+ transfer. Moreover, a large rate enhancement for the reaction of ethionine with [PtBr2(CN4)]2- compared with [PtCl2(CN4)]2- strongly supports an X+ transfer mechanism. Furthermore, a combined quantum-mechanical/molecular-mechanical (QM/MM) method was utilized to simulate a Cl+ transfer mechanism from trans-[PtCl2(CN)4]2- to ethionine. The simulations unraveled the energetically stable structures of reactants and products, which favor the Cl+ transfer process. Rate constants of the rate-determining steps have been derived. Ratios of k (ethionine)/k (Met) are between 2.2 and 2.6 obtained for the three protolytic species of ethionine and Met; the enhanced reactivity might be partially responsible for the disparate biological profiles.

Reduction of ormaplatin by an extended series of thiols unravels a remarkable correlation.

Ormaplatin ([Pt(dach)Cl4]) represents one of the three primary structural prototypes of Pt(iv) anticancer-active prodrugs. The reduction of ormaplatin by an extended series of thiols has been studied kinetically in a broad pH range. A novel and remarkable correlation between log kRS- and the thiol dissociation constants pKRSH is disclosed: log kRS- = (0.50 ± 0.02)pKRSH + (0.68 ± 0.13), where kRS- denotes the second-order rate constant of each thiolate towards the reduction of ormaplatin.

Kinetics and mechanism of oxidation of the anti-tubercular prodrug isoniazid and its analog by iridium(iv) as models for biological redox systems.

A complex reaction mechanism of oxidation of the anti-tubercular prodrug isoniazid (isonicotinic hydrazide, INH) by [IrCl6]2- as a model for redox processes of such drugs in biological systems has been studied in aqueous solution as a function of pH between 0 and 8.5. Similar experiments have been performed with its isomer nicotinic hydrazide (NH). All reactions are overall second-order, first-order in [IrCl6]2- and hydrazide, and the observed second-order rate constants k' have been determined as a function of pH. Spectrophotometric titrations indicate a stoichiometry of [Ir(iv)] : [hydrazide] = 4 : 1. HPLC analysis shows that the oxidation product of INH is isonicotinic acid. The derived reaction mechanism, based on rate law, time-resolved spectra and stoichiometry, involves parallel attacks by [IrCl6]2- on all four protolytic species of INH and NH as rate-determining steps, depending on pH. These steps are proposed to generate two types of hydrazyl free radicals. These radicals react further in three rapid consecutive processes, leading to the final oxidation products. Rate constants for the rate-determining steps have been determined for all protolytic species I-IV of INH and NH. They are used to calculate reactivity-pH diagrams. These diagrams demonstrate that for both systems, species IV is ca. 105 times more reactive in the redox process than the predominant species III at the physiological pH of 7.4. Thus, species IV will be the main reactant, in spite of the fact that its concentration at this pH is extremely low, a fact that has not been considered in previous work. The results indicate that pH changes might be an important factor in the activation process of INH in biological systems also, and that in such systems this process most likely is more complicated than previously assumed.

Reactivity of the glutathione species towards the reduction of ormaplatin (or tetraplatin).

The reduction of ormaplatin (tetraplatin), a prototype for Pt(IV) anticancer prodrugs, by glutathione (GSH) was kinetically characterized over a wide pH range at 25.0°C and 1.0M ionic strength. The reduction follows overall second-order kinetics, giving rise to the oxidized glutathione as the oxidation product, which was identified by high-resolution mass spectrometry. The reaction mechanism put forward involves parallel attacks by all the GSH species on the Pt(IV) prodrug as rate-determining steps. All rate constants for the rate-determining steps have been derived for the first time, enabling the construction of the reactivity of GSH species versus their pH distribution diagram. The diagram clearly displays that only one out of the five GSH species is the mainly responsible for the reduction of ormaplatin at the physiological pH of 7.4.

Reduction of ormaplatin and cis-diamminetetrachloroplatinum(iv) by ascorbic acid and dominant thiols in human plasma: kinetic and mechanistic analyses.

The reductions of Pt(iv) anticancer prodrugs [Pt(dach)Cl4] (ormaplatin/tetraplatin), cis-[Pt(NH3)2Cl4], and cis,cis,trans-[Pt(NH3)2Cl2Br2] by the several dominant reductants in human plasma have been characterized kinetically in this work, including l-ascorbic acid (Asc), l-glutathione (GSH), l-cysteine (Cys), dl-homocysteine (Hcy), and a dipeptide Gly-Cys. All the reductions follow an overall second-order kinetics, being first-order each in [Pt(iv)] and in the [reductant]. A general reactivity trend of Asc < Hcy < Cys-Gly < GSH < Cys is clearly revealed for the reductions of [Pt(dach)Cl4] and [Pt(NH3)2Cl4] at 37.0 °C and pH 7.40. Analysis of the observed second-order rate constants k' implies that these Pt(iv) prodrugs have a very short lifetime (less than a minute) in human plasma and can hardly enter into cells before reduction and that Asc might not play a dominant role in the reduction process among the reductants. The reductions of [Pt(dach)Cl4] and [Pt(NH3)2Cl4] by Asc have been studied in a wide pH range, and a reaction mechanism has been proposed involving parallel reductions of the Pt(iv) complexes by the Asc protolytic species. Moreover, a halide-bridged (inner-sphere) electron transfer mode for the rate-determining steps is discussed in detail; several lines of evidence strongly bolster this type of electron transfer. Furthermore, the observed activation parameters corresponding to k' have been measured around pH 7.40. Analysis of the established k'-pH profiles indicates that k' is a composite of at least three parameters in the pH range of 5.74-7.40 and the measured activation parameters in this range do not correspond to a single rate-determining step. Consequently, the isokinetic relationship reported previously using the measured ΔH(‡) and ΔS(‡) in the above pH range might be an artifact since the relationship is not justified anymore when our new data are added.

L-selenomethionine reduces platinum(IV) anticancer model compounds at strikingly faster rates than L-methionine.

L-Selenomethionine (SeMet), the predominant form of selenium acquired from the diet by humans, has been used as a supplement, and exhibit some important functions like cancer prevention and antioxidative defense. Its interactions with Pt(II) anticancer drugs have been characterized, but its redox reactions with platinum(IV) anticancer prodrugs have not been exploited. In this work, the oxidation of SeMet by Pt(IV) anticancer model compounds trans-[PtX2(CN)4](2-) (X = Cl, Br) was characterized. A stopped-flow spectrometer was used to record the rapid scan spectra and to follow the reaction kinetics over a wide pH range. An overall second-order rate law was derived: -d[Pt(IV)]/dt = k'[Pt(IV)][SeMet], where k' pertains to the observed second-order rate constants. The k'-pH profiles showed that k' increased only about 6 times even though the solution pH was varied from 0.25 to 10.5. The redox stoichiometry was determined as Δ[Pt(IV)]/Δ[SeMet] = 1 : (1.07 ± 0.07), suggesting that SeMet was oxidized to selenomethionine selenoxide. The selenoxide together with its hydrated form was identified explicitly by high resolution mass spectral analysis. A reaction mechanism was proposed which encompassed three parallel rate-determining steps relying on the protolytic species of SeMet. Rate constants of the rate-determining steps were obtained from the simulations of the k'-pH profiles. Activation parameters were determined for the reactions of the zwitterionic form of SeMet with the Pt(IV) complexes. A bridged electron transfer process is delineated in the rate-determining steps and several lines of evidence support the bridged electron transfer mode. Strikingly, reduction of [PtX2(CN)4](2-) by SeMet is 3.7 × 10(3)-5.7 × 10(4) times faster than that by L-methionine. Some potential biological consequences resulting from the strikingly fast reduction are discussed.