Kinetic analysis of γ-glutamyltransferase reaction process for measuring activity via an integration strategy at low concentrations of γ-glutamyl p-nitroaniline

Concentration and health risk assessment of 16 rare earth elements in six types of tea in China

Rare Earth Elements (REEs) have been implicated in potential health effects. However, the health risk of REE exposure among tea drinkers in China remains poorly understood. This study aimed to characterize the concentration of REEs in different tea categories and evaluate the associated health risks for tea consumers in China. By analyzing the content of 16 REEs in 4326 tea samples from China, the exposure level of REEs to the general population was estimated. The content of these 16 REEs was similar across six types of tea, with oolong tea exhibiting the highest levels. The concentration of light rare earth elements (LREEs) in six types of tea was higher than that of heavy rare earth elements (HREEs). The daily mean and 95th percentile (P95) exposure to REEs from tea for the general population in China were 0.0328 μg/kg BW and 0.1283 μg/kg BW, respectively, which are significantly lower than the temporary acceptable daily dose (tADI). Our findings suggest that REEs from tea do not pose a known health risk to Chinese consumers.

Transcriptome and metabolome analysis revealed the changes of Geniposide and Crocin content in Gardenia jasminoides fruit

BACKGROUND

Gardenia jasminoides Ellis is a perennial evergreen shrub of G. jasminoides of Rubiaceae. Geniposide and Crocin are important components in the fruit of G. jasminoides. In addition to being used as medicinal materials, they are also widely used in food, medicine, cosmetics, and other fields. They have high medicinal value, economic value, and ornamental value. However, at present, the utilization rate of G. jasminoides resources is low, mainly focused on germplasm cultivation, primary processing, and clinical pharmacology, and there are few studies on the quality of Gardenia fruit.

METHODS AND RESULTS

Based on transcriptome sequencing and metabolic group analysis, the morphological and structural changes of Gardenia fruit with young fruit, middle fruit, and ripe fruit were analyzed, and the formation mechanism and content changes of Geniposide and Crocin in Gardenia fruit were studied. The content of Geniposide decreased with the development of fruit, so did the expression of the main structural gene GES, G10H, and IS in its synthesis pathway, while the content of Crocin increased with the development of fruit, and the expression of the main structural gene CCD, ALDH, and UGT in its synthesis pathway also increased. The relationship between the morphological structure of G. jasminoides and the accumulation of Geniposide and Crocin was summarized.

CONCLUSIONS

This study not only provides a theoretical basis for the mining and utilization of Geniposide and Crocin, but also provides a theoretical basis for genetic background for the identification and cloning of bioactive substances in gardenia fruit in future. At the same time, it provides support for increasing the dual-use value of G. jasminoides and breeding excellent germplasm resources.

Comparative transcriptomics and bioinformatics analysis of genes related to photosynthesis in Eucalyptus camaldulensis

The timber species Eucalyptus camaldulensis is one of the most important in southern China. Therefore, it is essential to understand the photosynthetic pattern in eucalyptus leaves. In the present study, eighteen photosynthesis-related genes were analyzed using bioinformatics methods. The results indicated that there were ten differentially expressed ribose-5-phosphate isomerase genes (RPI), and six of them were up-regulated in the mature leaves compared to the young leaves, while others were down-regulated. The differential expression of four rubisco methyltransferase genes (RBCMT) were observed. Two of them were up-regulated, while two were down-regulated in mature leaves compared to young leaves. Furthermore, two ribulose-phosphate-3-epimerase genes (RPE) were up-regulated in the mature leaves compared to the young leaves. In contrast, two genes involved in triosephosphate isomerase (TIM) were down-regulated in mature leaves compared with young leaves. The current study provides basic information about the transcriptome of E. camaldulensis and lays a foundation for further research in developing and utilizing important photosynthetic genes.

Combined analysis of lipidomics and transcriptomics revealed the key pathways and genes of lipids in light-sensitive albino tea plant (Camellia sinensis cv. Baijiguan)

Currently, the mechanism by which light-sensitive albino tea plants respond to light to regulate pigment synthesis has been only partially elucidated. However, few studies have focused on the role of lipid metabolism in the whitening of tea leaves. Therefore, in our study, the leaves of the Baijiguan (BJG) tea tree under shade and light restoration conditions were analyzed by a combination of lipidomics and transcriptomics. The leaf color of BJG was regulated by light intensity and responded to light changes in light by altering the contents and proportions of lipids. According to the correlation analysis, we found three key lipid components that were significantly associated with the chlorophyll SPAD value, namely, MGDG (36:6), DGDG (36:6) and DGDG (34:3). Further weighted gene coexpression network analysis (WGCNA) showed that HY5 TF and GLIP genes may be hub genes involved lipid regulation in albino tea leaves. Our results lay a foundation for further exploration of the color changes in albino tea leaves.

Combined transcriptome and metabolome analysis of the resistance mechanism of quinoa seedlings to Spodoptera exigua

Quinoa has attracted considerable attention owing to its unique nutritional, economic, and medicinal values. The damage intensity of Spodoptera exigua at the seedling stage of quinoa fluctuates with the crop's biological cycle and the environmental changes throughout the growing season. In this study, we used independently selected quinoa seedling resistant and susceptible cultivars to investigate the difference between insect resistance and insect susceptibility of quinoa at the seedling stage. Samples were collected when Spodoptera exigua 45 days after planting the seedlings, and broad targeted metabolomics studies were conducted using liquid chromatography-mass spectrophotometry combined with transcriptomic co-analysis. The metabolomic and genomic analyses of the insect-resistant and insect-susceptible quinoa groups revealed a total of 159 differential metabolites and were functionally annotated to 2334 differential genes involved in 128 pathways using the Kyoto Encyclopedia of Genes and Genomes analysis. In total, 14 metabolites and 22 genes were identified as key factors for the differential accumulation of insect-resistant metabolites in quinoa seedlings. Among them, gene-LOC110694254, gene-LOC110682669, and gene-LOC110732988 were positively correlated with choline. The expression of gene-LOC110729518 and gene-LOC110723164, which were notably higher in the resistant cultivars than in the susceptible cultivars, and the accumulations of the corresponding metabolites were also significantly higher in insect-resistant cultivars. These results elucidate the regulatory mechanism between insect resistance genes and metabolite accumulation in quinoa seedlings, and can provide a basis for the breeding and identification of new insect-resistant quinoa cultivars as well as for screening potential regulatory metabolites of quinoa insect-resistant target genes.

Recent Advances in Nattokinase-Enriched Fermented Soybean Foods: A Review

With the dramatic increase in mortality of cardiovascular diseases (CVDs) caused by thrombus, this has sparked an interest in seeking more effective thrombolytic drugs or dietary nutriments. The dietary consumption of natto, a traditional Bacillus-fermented food (BFF), can reduce the risk of CVDs. Nattokinase (NK), a natural, safe, efficient and cost-effective thrombolytic enzyme, is the most bioactive ingredient in natto. NK has progressively been considered to have potentially beneficial cardiovascular effects. Microbial synthesis is a cost-effective method of producing NK. Bacillus spp. are the main production strains. While microbial synthesis of NK has been thoroughly explored, NK yield, activity and stability are the critical restrictions. Multiple optimization strategies are an attempt to tackle the current problems to meet commercial demands. We focus on the recent advances in NK, including fermented soybean foods, production strains, optimization strategies, extraction and purification, activity maintenance, biological functions, and safety assessment of NK. In addition, this review systematically discussed the challenges and prospects of NK in actual application. Due to the continuous exploration and rapid progress of NK, NK is expected to be a natural future alternative to CVDs.

Odorant Binding Protein C17 Contributes to the Response to Artemisia vulgaris Oil in Tribolium castaneum

The red flour beetle, Tribolium castaneum (T. castaneum), generates great financial losses to the grain storage and food processing industries. Previous studies have shown that essential oil (EO) from Artemisia vulgaris (A. vulgaris) has strong contact toxicity to larvae of the beetle, and odorant-binding proteins (OBPs) contribute to the defense of larvae against A. vulgaris. However, the functions of OBPs in insects defending against plant oil is still not clear. Here, expression of one OBP gene, TcOBPC17, was significantly induced 12–72 h after EO exposure. Furthermore, compared to the control group, RNA interference (RNAi) against TcOBPC17 resulted in a higher mortality rate after EO treatment, which suggests that TcOBPC17 involves in the defense against EO and induces a declining sensitivity to EO. In addition, the tissue expression profile analysis revealed that the expression of TcOBPC17 was more abundant in the metabolic detoxification organs of the head, fat body, epidermis, and hemolymph than in other larval tissue. The expression profile of developmental stages showed that TcOBPC17 had a higher level in early and late adult stages than in other developmental stages. Taken together, these results suggest that TcOBPC17 could participate in the sequestration process of exogenous toxicants in T. castaneum larvae.

Comparative Transcriptome Profiling Analysis Reveals the Adaptive Molecular Mechanism of Yellow-Green Leaf in Rosa beggeriana 'Aurea'

Rosa beggeriana 'Aurea' is a yellow-green leaf (yl) mutant and originated from Rosa beggeriana Schrenk by 60Co-γ irradiation, which is an important ornamental woody species. However, the molecular mechanism of the yl mutant remains unknown. Herein, comparative transcriptome profiling was performed between the yl type and normal green color type (WT) by RNA sequencing. A total of 3,372 significantly differentially expressed genes (DEGs) were identified, consisting of 1,585 upregulated genes and 1,787 downregulated genes. Genes that took part in metabolic of biological process (1,090), membrane of cellular component (728), catalytic (1,114), and binding of molecular function (840) were significantly different in transcription level. DEGs involved in chlorophyll biosynthesis, carotenoids biosynthesis, cutin, suberine, wax biosynthesis, photosynthesis, chloroplast development, photosynthesis-antenna proteins, photosystem I (PSI) and photosystem II (PSII) components, CO2 fixation, ribosomal structure, and biogenesis related genes were downregulated. Meanwhile, linoleic acid metabolism, siroheme biosynthesis, and carbon source of pigments biosynthesis through methylerythritol 4-phosphate (MEP) pathways were upregulated. Moreover, a total of 147 putative transcription factors were signification different expression, involving NAC, WRKY, bHLH, MYB and AP2/ERF, C2H2, GRAS, and bZIP family gene. Our results showed that the disturbed pigments biosynthesis result in yl color by altering the ratio of chlorophylls and carotenoids in yl mutants. The yl mutants may evoke other metabolic pathways to compensate for the photodamage caused by the insufficient structure and function of chloroplasts, such as enhanced MEP pathways and linoleic acid metabolism against oxidative stress. This research can provide a reference for the application of leaf color mutants in the future.

Prediction of Suitable Distribution of a Critically Endangered Plant Glyptostrobus pensilis

Glyptostrobus pensilis is a critically endangered living fossil plant species of the Mesozoic era, with high scientific research and economic value. The aim of this study was to assess the impact of climate change on the potential habitat area of G. pensilis in East Asia. The MaxEnt (maximum entropy) model optimized by the ENMeval data package was used to simulate the potential distribution habitats of G. pensilis since the last interglacial period (LIG, 120–140 ka). The results showed that the optimized MaxEnt model has a high prediction accuracy with the area under the receiver operating characteristic curve (AUC) of 0.9843 ± 0.005. The Current highly suitable habitats were found in the Northeast Jiangxi, Eastern Fujian and Eastern Guangdong; the main climatic factors affecting the geographic distribution of G. pensilis are temperature and precipitation, with precipitation as the temperature factor. The minimum temperature of coldest month (Bio6) may be the key factor restricting the northward distribution of G. pensilis; during the LIG, it contracted greatly in the highly suitable habitat area. Mean Diurnal Range (Bio2), Minimum Temperature of Coldest Month (Bio6), Annual Precipitation (Bio12) and Mean Temperature of Driest Quarter (Bio9) may be important climatic factors causing the changes in geographic distribution. In the next four periods, the suitable areas all migrated southward. Except for the RCP2.6-2070s, the highly suitable areas in the other three periods showed varying degrees of shrinkage. The results will provide a theoretical basis for the management and resource protection of G. pensilis.

Analysis of Chloroplast Genomes Provides Insights Into the Evolution of Agropyron

Plants of the Agropyron genus are important pasture resources, and they also play important roles in the ecological restoration. Chloroplast genomes are inherited from maternal parents, and they are important for studying species taxonomy and evolution. In this study, we sequenced the complete chloroplast genomes of five typical species of the Agropyron genus (eg., A. cristatum × A. desertorum Fisch. Schult, A. desertorum, A. desertorum Fisch. Schult. cv. Nordan, A. michnoi Roshev, and A. mongolicum Keng) using the Illumina NovaSeq platform. We found that these five chloroplast genomes exhibit a typical quadripartite structure with a conserved genome arrangement and structure. Their chloroplast genomes contain the large single-copy regions (LSC, 79,613 bp-79,634 bp), the small single-copy regions (SSC, 12,760 bp-12,768 bp), and the inverted repeat regions (IR, 43,060 bp-43,090 bp). Each of the five chloroplast genomes contains 129 genes, including 38 tRNA genes, eight rRNA genes, and 83 protein-coding genes. Among them, the genes trnG-GCC, matK, petL, ccsA, and rpl32 showed significant nucleotide diversity in these five species, and they may be used as molecular markers in taxonomic studies. Phylogenetic analysis showed that A. mongolicum is closely related to A. michnoi, while others have a closer genetic relationship with the Triticum genus.

Comparative and Phylogenetic Analysis of Complete Plastomes among Aristidoideae Species (Poaceae)

Aristidoideae is a subfamily in the PACMAD clade of family Poaceae, including three genera, Aristida, Stipagrostis, and Sartidia. In this study, the plastomes of Aristida adscensionis and Stipagrostis pennata were newly sequenced, and a total of 16 Aristidoideae plastomes were compared. All plastomes were conservative in genome size, gene number, structure, and IR boundary. Repeat sequence analysis showed that forward and palindrome repeats were the most common repeat types. The number of SSRs ranged from 30 (Sartidia isaloensis) to 54 (Aristida purpurea). Codon usage analysis showed that plastome genes preferred to use codons ending with A/T. A total of 12 highly variable regions were screened, including four protein coding sequences (matK, ndhF, infA, and rpl32) and eight non-coding sequences (rpl16-1-rpl16-2, ccsA-ndhD, trnY-GUA-trnD-GUC, ndhF-rpl32, petN-trnC-GCA, trnT-GGU-trnE-UUC, trnG-GCC-trnfM-CAU, and rpl32-trnL-UAG). Furthermore, the phylogenetic position of this subfamily and their intergeneric relationships need to be illuminated. All Maximum Likelihood and Bayesian Inference trees strongly support the monophyly of Aristidoideae and each of three genera, and the clade of Aristidoideae and Panicoideae was a sister to other subfamilies in the PACMAD clade. Within Aristidoideae, Aristida is a sister to the clade composed of Stipagrostis and Sartidia. The divergence between C₄ Stipagrostis and C₃ Sartidia was estimated at 11.04 Ma, which may be associated with the drought event in the Miocene period. Finally, the differences in carbon fixation patterns, geographical distributions, and ploidy may be related to the difference of species numbers among these three genera. This study provides insights into the phylogeny and evolution of the subfamily Aristidoideae.

Combined transcriptome and metabolome integrated analysis of Acer mandshuricum to reveal candidate genes involved in anthocyanin accumulation

The red color formation of Acer mandshuricum leaves is caused by the accumulation of anthocyanins primarily, but the molecular mechanism researches which underlie anthocyanin biosynthesis in A. mandshuricum were still lacking. Therefore, we combined the transcriptome and metabolome and analyzed the regulatory mechanism and accumulation pattern of anthocyanins in three different leaf color states. In our results, 26 anthocyanins were identified. Notably, the metabolite cyanidin 3-O-glucoside was found that significantly correlated with the color formation, was the predominant metabolite in anthocyanin biosynthesis of A. mandshuricum. By the way, two key structural genes ANS (Cluster-20561.86285) and BZ1 (Cluster-20561.99238) in anthocyanidin biosynthesis pathway were significantly up-regulated in RL, suggesting that they might enhance accumulation of cyanidin 3-O-glucoside which is their downstream metabolite, and contributed the red formation of A. mandshuricum leaves. Additionally, most TFs (e.g., MYBs, bZIPs and bHLHs) were detected differentially expressed in three leaf color stages that could participate in anthocyanin accumulation. This study sheds light on the anthocyanin molecular regulation of anthocyanidin biosynthesis and accumulation underlying the different leaf color change periods in A. mandshuricum, and it could provide basic theory and new insight for the leaf color related genetic improvement of A. mandshuricum.

Maize ZmbZIP33 Is Involved in Drought Resistance and Recovery Ability Through an Abscisic Acid-Dependent Signaling Pathway

Analyzing the transcriptome of maize leaves under drought stress and rewatering conditions revealed that transcription factors were involved in this process, among which ZmbZIP33 of the ABSCISIC ACID-INSENSITIVE 5-like protein 5 family was induced to significantly up-regulated. The functional mechanism of ZmbZIP33 in Abscisic acd (ABA) signaling pathway and its response to drought stress and rewatering has not been studied yet. The present study found that ZmbZIP33 contains a DNA-binding and dimerization domain, has transcriptional activation activity, and is highly homologous to SbABI1,SitbZIP68 and OsABA1. The expression of ZmbZIP33 is strongly up-regulated by drought, high salt, high temperature, and ABA treatments. Overexpression of ZmbZIP33 remarkably increased chlorophyll content and root length after drought stress and rewatering, and, moreover, cause an accumulation of ABA content, thereby improving drought resistance and recovery ability in Arabidopsis. However, silencing the expression of ZmbZIP33 (BMV-ZmbZIP33) remarkably decreased chlorophyll content, ABA content, superoxide dismutase and peroxidase activities, and increased stomatal opening and water loss rate compared with BMV (control). It showed that silencing ZmbZIP33 lead to reduced drought resistance and recovery ability of maize. ABA sensitivity analysis found that 0.5 and 1 μmol/L treatments severely inhibited the root development of overexpression ZmbZIP33 transgenic Arabidopsis. However, the root growth of BMV was greatly inhibited for 1 and 5μmol/L ABA treatments, but not for BMV-ZmbZIP33. Subcellular localization, yeast two-hybrid and BIFC further confirmed that the core components of ABA signaling pathways ZmPYL10 and ZmPP2C7 interacted in nucleus, ZmPP2C7 and ZmSRK2E as well as ZmSRK2E and ZmbZIP33 interacted in the plasma membrane. We also found that expression levels of ZmPYL10 and ZmSRK2E in the BMV-ZmbZIP33 mutant were lower than those of BMV, while ZmPP2C7 was the opposite under drought stress and rewatering. However, expression of ZmPYL10 and ZmSRK2E in normal maize leaves were significantly up-regulated by 3-4 folds after drought and ABA treatments for 24 h, while ZmPP2C7 was down-regulated. The NCED and ZEP encoding key enzymes in ABA biosynthesis are up-regulated in overexpression ZmbZIP33 transgenic line under drought stress and rewatering conditions, but down-regulated in BMV-ZmbZIP33 mutants. Together, these findings demonstrate that ZmbZIP33 played roles in ABA biosynthesis and regulation of drought response and rewatering in Arabidopsis and maize thought an ABA-dependent signaling pathway.

Biological materials formed by Acidithiobacillus ferrooxidans and their potential applications

A variety of biological materials including schwertmannite, jarosite, iron-sulfur cluster (ISC) and magnetosomes can be produced by Acidithiobacillus ferrooxidans (A. ferrooxidans). Their possible formation mechanisms involved in iron transformation, iron transport, and electron transfer were proposed. The schwertmannite formation usually occurs under the pH of 2.0-3.51, and a lower or higher pH will promote jarosite to be produced. Available Fe2+ in the environment and the carrier proteins that can transport Fe2+ to the intracellular membranes of A. ferrooxidans play a critical role in the synthesis of magnetosomes and ISC. The potential applications of these biological materials were reviewed, including removal of heavy metal by schwertmannite, detoxification of toxic species by jarosite, the transference of electron and ripening the iron sulfur protein by ISC, and biomedical application of magnetosomes. Additionally, some perspectives for the molecular mechanisms of synthesis and regulation of these biomaterials were briefly described.

Odorant-Binding Proteins Contribute to the Defense of the Red Flour Beetle, Tribolium castaneum, Against Essential Oil of Artemisia vulgaris

The function of odorant-binding proteins (OBPs) in insect chemodetection has been extensively studied. However, the role of OBPs in the defense of insects against exogenous toxic substances remains elusive. The red flour beetle, Tribolium castaneum, a major pest of stored grains, causes serious economic losses for the agricultural grain and food processing industries. Here, biochemical analysis showed that essential oil (EO) from Artemisia vulgaris, a traditional Chinese medicine, has a strong contact killing effect against larvae of the red flour beetle. Furthermore, one OBP gene, TcOBPC11, was significantly induced after exposure to EO. RNA interference (RNAi) against TcOBPC11 led to higher mortality compared with the controls after EO treatment, suggesting that this OBP gene is associated with defense of the beetle against EO and leads to a decrease in sensitivity to the EO. Tissue expression profiling showed that expression of TcOBPC11 was higher in the fat body, Malpighian tubule, and hemolymph than in other larval tissues, and was mainly expressed in epidermis, fat body, and antennae from the early adult. The developmental expression profile revealed that expression of TcOBPC11 was higher in late larval stages and adult stages than in other developmental stages. These data indicate that TcOBPC11 may be involved in sequestration of exogenous toxicants in the larvae of T. castaneum. Our results provide a theoretical basis for the degradation mechanism of exogenous toxicants and identify potential novel targets for controlling the beetle.

The identification of key candidate genes mediating yellow seedling lethality in a Lilium regale mutant

Leaf color mutants are ideal materials for exploring plant photosynthesis mechanisms, chlorophyll biosynthetic pathways and chloroplast development. The yellow seedling lethal mutant lrysl1 was discovered from self-bred progenies of Lilium regale; however, the mechanism of leaf color mutation remains unclear. In this study, the ultrastructural and physiological features and de novo RNA-Seq data of a L. regale leaf color mutant and wild-type L. regale were investigated. Genetic analysis indicated that the characteristics of the lrysl1 mutant were controlled by a recessive nuclear gene. The chlorophyll a, chlorophyll b and carotenoid contents in the mutant leaves were lower than those in the wild-type leaves. Furthermore, the contents of the chlorophyll precursors aminolevulinic acid (ALA), porphobilinogen (PBG), protoporphyrin IX (ProtoIX), Mg-protoporphyrin IX (Mg-ProtoIX), and protochlorophyll (Pchl) decreased significantly in mutant leaves. Transcriptome data from the mutant and wild type showed that a total of 892 differentially expressed genes were obtained, of which 668 and 224 were upregulated genes and downregulated genes in the mutant, respectively. Almost all genes in the photosynthesis pathway and chlorophyll biosynthetic pathway were downregulated in the mutant, which corroborated the differences in the physiological features mentioned above. Further research indicated that the chloroplasts of the mutant leaves exhibited an abnormal morphology and distribution and that the expression of a gene related to chloroplast development was downregulated. It was concluded that abnormal chloroplast development was the main cause of leaf color mutation in the mutant lrysl1 and that LrGLK was a gene related to chloroplast development in L. regale. This research provides a foundation for further research on the mechanism by which LrGLK regulates chloroplast development in L. regale.

Spectrophotometric-dual-enzyme-simultaneous assay in one reaction solution: chemometrics and experimental models

Spectrophotometric-dual-enzyme-simultaneous assay in one reaction solution (SDESA) is proposed. SDESA requires the following: (a) Enzyme A acts on Substrate A to release Product A bearing the longest difference absorbance peak (λ(A)) much larger than that of Product B (λ(B)) formed by Enzyme B action on Substrate B; λ(B) is close to the longest isoabsorbance wavelength of Product A and Substrate A (λ(0)); (b) absorbance at λ(A) and λ(0) is quantified via swift alternation of detection wavelengths and corrected on the basis of absorbance additivity; (c) inhibition/activation on either enzyme by any substance is eliminated; (d) Enzyme A is quantified via an integration strategy if levels of Substrate A are lower than the Michaelis constant. Chemometrics of SDESA was tested with γ-glutamyltransferase and lactate-dehydrogenase of complicated kinetics. γ-Glutamyltransferase releases p-nitroaniline from γ-glutamyl-p-nitroaniline with λ(0) at 344 nm and λ(A) close to 405 nm, lactate-dehydrogenase consumes reduced nicotinamide dinucleotide bearing λ(B) at 340 nm. Kinetic analysis of reaction curve yielded lactate-dehydrogenase activity free from inhibition by p-nitroaniline; the linear range of initial rates of γ-glutamyltransferase via the integration strategy, and that of lactate-dehydrogenase after interference elimination, was comparable to those by separate assays, respectively; the quantification limit of either enzyme by SDESA at 25-fold higher activity of the other enzyme remained comparable to that by a separate assay. To test potential application, SDESA of alkaline phosphatase (ALP) and β-D-galactosidase as enzyme-linked-immunoabsorbent assay (ELISA) labels were examined. ALP releases 4-nitro-1-naphthol from 4-nitronaphthyl-1-phosphate with λ(0) at 405 nm and λ(A) at 458 nm, β-D-galactosidase releases 4-nitrophenol from β-D-(4-nitrophenyl)-galactoside with λ(B) at 405 nm. No interference from substrates/products made SDESA of β-galactosidase and ALP simple for ELISA of penicillin G and clenbuterol in one well, and the quantification limit of either hapten was comparable to that via a separate assay. Hence, SDESA is promising.

Integration of kinetic analysis of reaction curve with a proper classical approach for enzymatic analysis

For enzymatic analysis to quantify a substrate or enzyme, kinetic analysis of reaction curve can be integrated with a proper classical approach. For their integration, they should have consistent slopes and intercepts of linear response and an overlapped region of analyte quantities measurable under optimized conditions. To quantify a substrate after optimizations of tool enzyme activity and reaction duration, the equilibrium method works when the reaction is completed within the reaction duration; otherwise, kinetic analysis of reaction curve applies providing at least seven data with sufficient consumption of substrate. To quantify an enzyme after optimizations of initial substrate concentration and reaction duration, the classical initial rate method works when an estimated initial rate locates within the linear range; otherwise, kinetic analysis of reaction curve applies after the conversion of the quantification index with optimized parameters. This integration strategy has ideal linear ranges and practical efficiency for quantifying an enzyme at moderate substrate levels and for quantifying a substrate at moderate cost on tool enzyme; it has promise to simultaneous assays of multiple enzymes in one reaction vessel each time and ,thus, potential applications to concurrently quantify multiple serum enzymes, screen inhibitors against multiple enzyme targets, and detect multiple serum components by enzymeimmunoassay.