A sensor array based on a nanozyme with polyphenol oxidase activity for the identification of tea polyphenols and Chinese green tea.

Green tea is popular among consumers because of its high nutritional value and unique flavor. There is often a strong correlation among the type of tea, its quality level and the price. Therefore, the rapid identification of tea types and the judgment of tea quality grades are particularly important. In this work, a novel sensor array based on nanozyme with polyphenol oxidase (PPO) activity is proposed for the identification of tea polyphenols (TPs) and Chinese green tea. The absorption spectra changes of the nanozyme and its substrate in the presence of different TPs were first investigated. The feature spectra were scientifically selected using genetic algorithm (GA), and then a sensor array with 15 sensing units (5 wavelengths × 3 time) was constructed. Combined with the support vector machine (SVM) discriminative model, the discriminative rate of this sensor array was 100% for different concentrations of typical TPs in Chinese green tea with a detection limit of 5 µM. In addition, the identification of different concentrations of the same tea polyphenols and mixed tea polyphenols have also been achieved. Based on the above study, we further developed a facile and efficient new method for the category differentiation and adulteration identification of green tea, and the accuracy of this array was 96.88% and 100% for eight types of green teas and different adulteration ratios of Biluochun, respectively. This work has significance for the rapid discrimination of green tea brands and adulteration.

Comparative metaproteomics reveal co-contribution of onion maggot and its gut microbiota to phoxim resistance.

Pesticide resistance inflicts significant economic losses on a global scale each year. To address this pressing issue, substantial efforts have been dedicated to unraveling the resistance mechanisms, particularly the newly discovered microbiota-derived pesticide resistance in recent decades. Previous research has predominantly focused on investigating microbiota-derived pesticide resistance from the perspective of the pest host, associated microbes, and their interactions. However, a gap remains in the quantification of the contribution by the pest host and associated microbes to this resistance. In this study, we investigated the toxicity of phoxim by examining one resistant and one sensitive Delia antiqua strain. We also explored the critical role of associated microbiota and host in conferring phoxim resistance. In addition, we used metaproteomics to compare the proteomic profile of the two D. antiqua strains. Lastly, we investigated the activity of detoxification enzymes in D. antiqua larvae and phoxim-degrading gut microbes, and assessed their respective contributions to phoxim resistance in D. antiqua. The results revealed contributions by D. antiqua and its gut bacteria to phoxim resistance. Metaproteomics showed that the two D. antiqua strains expressed different protein profiles. Detoxifying enzymes including Glutathione S-transferases, carboxylesterases, Superoxide Dismutase, Glutathione Peroxidase, and esterase B1 were overexpressed in the resistant strain and dominated in differentially expressed insect proteins. In addition, organophosphorus hydrolases combined with a group of ABC type transporters were overexpressed in the gut microbiota of resistant D. antiqua compared to the sensitive strain. 85.2% variation of the larval mortality resulting from phoxim treatment could be attributed to the combined effects of proteins from both from gut bacteria and D. antiqua, while the individual contribution of proteins from gut bacteria or D. antiqua alone accounted for less than 10% of the variation in larval mortality caused by phoxim. The activity of the overexpressed insect enzymes and the phoxim-degrading activity of gut bacteria in resistant D. antiqua larvae were further confirmed. This work enhances our understanding of microbiota-derived pesticide resistance and illuminates new strategies for controlling pesticide resistance in the context of insect-microbe mutualism.

Plastid genome sequencing, identification of nuclear SNP markers, and quality assessment of medicinal rhizomatous herb Polygonatum odoratum (Asparagaceae) cultivars.

Polygonatum odoratum (Mill.) Druce (Asparagaceae, Asparagales) is a widely cultivated medicinal herb in China. However, this useful herb is understudied despite being known as a medicinal resource with top grade medical and edible properties since long. In this study, P. odoratum and four cultivars were investigated. The variations in morphological characteristics and vegetative phases of each cultivar were observed. For genetic aspect, the plastid genome of P. odoratum varies in length from 154,569 bp to 155,491 bp, containing a large single-copy region of 83,486-84,459 bp, a small single-copy region of 18,292-18,471 bp, and two inverted repeats of 26,302-26,370 bp. A total of 131 genes were predicted, including 85 protein-coding, 38 tRNA, and eight rRNA genes. Genome comparisons revealed a slight variation in the sequence across the five accessions, but two highly variable regions (trnC-petN and rpl32-trnL) were detected when comparing the four different cultivars. For the RAD-seq markers, a total of 33.64 Gb of clean data, with an average value of 1.08 Gb per sample, were analyzed for the presence of single nucleotide polymorphisms (SNPs). Well-resolved phylogenies of the P. odoratum cultivars are constructed; the nonmonophyletic relationship in the plastome-based phylogenetic trees, yet monophyletic form in the RAD-based linkage map suggested possibility of hybrid cultivar for P. odoratum "Dazhu" (GDDZ), which was further supported by morphological observations. Quality assessment based on the standards of the Chinese Pharmacopoeia on Polygonati Odorati Rhizoma (POR) on the four cultivars used in this study recorded that PORs from P. odoratum "Zhongzhu" (GDZZ) met the minimum criteria for the acceptance as raw material for medicinal drug production. This study has provided insights on the morphological variations, genetic background, and medicinal qualities of P. odoratum cultivars that could be explored for future genetic improvement as well as breeding programs of P. odoratum for POR production.

Cajanol inhibits the growth of Escherichia coli and Staphylococcus aureus by acting on membrane and DNA damage.

In the present study, the mechanism of antibacterial activity of cajanol extracted from the roots of Cajanus cajan (L.) Millsp. towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was investigated. The antibacterial activity of cajanol was evaluated towards six bacterial strains (Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Proteus vulgaris, and Pseudomonas aeruginosa) by the broth microdilution method. It showed strong antibacterial activity towards all bacteria tested with minimal inhibition concentration (MIC) values ranging from 98.90 µM to 197.8 µM. Cajanol-induced death rates in the most sensitive strains ( E.COLI, 96.55 % and S. AUREUS, 97.25 %) were analyzed by flow cytometry. Furthermore, the activity of cajanol on the membranes of E. coli and S. aureus was investigated by using lecithin, phosphate groups, and fluorescence microscopy. Cajanol-induced DNA damage was observed by agarose gel electrophoresis. In summary, cajanol inhibited E. coli only by DNA damage, whereas S. aureus was inhibited by affecting both, the lecithin and phosphate groups on the cellular membrane and DNA. The present study shows that cajanol possesses antibacterial activity in vitro towards both gram-negative and gram-positive bacteria and therefore may be a promising candidate as an antibacterial agent for the therapy of microbial infections.

[Study on the relation between iodine nutrition of pregnant women in different occasions and thyroid function of their neonates].

OBJECTIVE: To study iodine nutrition of pregnant women in different occasions and thyroid function of their neonates. METHODS: Urinary iodine of pregnant women and their serum T(3), T(4), FT(3), FT(4) were determined by chloric acid-digestion thermostatic assay and RIA, TSH determination by IRMA; neonatal umbilical cord blood TSH was determined by ELISA. RESULTS: Median urinary iodine of pregnant women were 206.3 microg/L, 161.4 microg/L, 203.3 microg/L at 10 - 14 (first occasion), 23 - 27 (second occasion) and 39 - 40 (third occasion) week but the percentage that lower than 100 microg/L were 14.6%, 17.1%, 11.1% respectively. Serum T(3), T(4) of pregnant women was significantly higher than those women of premarital health inspection (PHIW, P < 0.001). The difference of serum T(3), T(4) of pregnant women at 10 - 14 and 39 - 40 week was not significant. Serum FT(3), FT(4) of pregnant women at 39 - 40 week were 2.61 +/- 0.47 pmol/L and 5.50 +/- 1.57 pmol/L respectively. The difference of serum TSH concentration at third occasion and first occasion of pre-pregnancy was significant but the difference of TSH frequency distribution in three groups was not significant (chi(2) = 1.138, P > 0.5). Blood TSH median neonatal umbilical cord was 1.99 mU/L but the percentage that higher than 5 mU/L was 9.4%. CONCLUSION: For those areas with high iodized salt coverage, pregnant women had had sufficient iodine supplement and good thyroid function. The percentage of neonates from iodine sufficient pregnant women with TSH > 5 mU/L was lower than 10%. Using the normal range of nonpregnant FT(3) and FT(4) to estimate the thyroid function of pregnant women could cause mis diagnosis.