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关键词： Stevia rebaudiana   salicylic acid   yeast extract   steviol glycosides   gene expression  

摘要： Stevia rebaudiana Bert. is a medicinal plant used as a calorie-free sweetener due to the presence of steviol glycosides in its leaves. The present study evaluated morphological, biochemical, and molecular changes of stevia under salicylic acid (SA) elicitors (0, 25, 50, 75 and 100 mu M) and yeast extract (YE) (0, 1, 2, 3 and 5 g/L) under in vitro conditions. The results showed significant effects of elicitors on morphological traits and photosynthetic pigments of stevia. The highest morphological traits were observed at 25 mu M and control treatments of SA and YE respectively. On the other hand, increasing the concentrations of both elicitors resulted in lowered morphological traits. In general, plants treated with YE showed lowered growth, with the concentration rise lowering the growth further. HPLC results showed an increase in steviol glycosides content in 50 mu M SA and 2 g/L YE treatments and then the highest amount of stevioside and rebaudioside A was at concentrations of 25 mu M and 3 g/L. Investigation of expression levels of four genes (KA13H, UGT74G1, UGT76G1, and UGT85C2) indicated that the highest rate of expression occurred at the concentrations of 50 mu M SA and 2 g/L of YE. While, control treatment had the lowest levels expression of the studied genes in both elicitors, which indicates the significant effect of elicitors compared to the control. These results demonstrate the significant effect of SA and YE at medium concentrations on levels of expression of key genes of biosynthetic pathway as well as the production of stevioside and rebaudioside A. Thus, this approach could be employed to elevate the steviol glycosides' levels under in vitro conditions.

关键词： Heavy metal   Photosynthesis   Gene expression   Antagonism   Mineral nutrients   Physiological parameters  

摘要： Lead (Pb) is a highly toxic metal for humans, animals and plants even at low concentrations in the soil. The ingestion of chocolate produced from contaminated beans can contribute to consumer exposure to Pb. While, Mn is an element essential for plants and participates as enzymatic cofactors in several metabolic pathways. The objective of this study was to evaluate the influence of Mn on mitigation of Pb toxicity in seedling of the cacao clonal CCN 51 genotype grown in soils with different doses of Pb, Mn and Mn+Pb, through physiological, biochemical, molecular and nutritional responses. It was found that the seedling of the cacao clonal CCN 51 genotype grown in soils with high Pb, Mn and Mn+Pb contents accumulated these heavy metals in the roots and leaves. Mn doses reduced the Pb uptake by root system and prevented that the Pb accumulated at toxic levels in the roots and leaves of the plants. High doses of Pb applied in soil were highly toxic to the plants, leading, in some cases, them to death. However, no Mn toxicity was observed in cocoa plants, even at high doses in the soil. Uptake of Pb and Mn by the roots and its transport into the aerial part of the plant promoted changes in photosynthesis, leaf gas exchange, respiration, carboxylation and in the instantaneous efficiency of carboxylation, reducing in the treatments with the highest concentrations of Pb, and the emission of chlorophyll fluorescence, affecting the efficiency of photosystem 2 and the production of photoassimilates. Besides that, Pb, Mn and Mn+Pb toxicities activated defense mechanisms in plants that alter the gene expression of met, psbA and psbO, increasing in plants subjected to high concentrations of Pb and the activity of the enzymes involved in the cellular detoxification of excess ROS at the leaf level. In addition, high uptake of Mn by root system was found to reduced Pb uptake in plants grown with Mn+Pb in the soil. Therefore, application of Mn in the soil can be used to mitigate the

关键词： Superficial scald   Pear   Cold storage   Chilling injury   Ripening   Antioxidant content  

摘要： The molecular and biochemical events underlying the onset of superficial scald in two pear cultivars with different susceptibility ('Blanquilla' and 'Conference') was investigated in fruit untreated and treated with lovastatin, 1-MCP or ethylene. 'Conference' pears were characterized by higher content of flavonols and linolenic acid (18:3), two metabolites related to chilling injury resistance. In this cultivar, the expression level of three genes belonging to the ascorbate glutathione pathway (APX, DHAR and MDHAR) were constitutively over expressed, highlighting the role that endogenous antioxidant potential played in scald control. In the scald-susceptible cultivar ('Blanquilla') the lovastatin treatment, in contrast to 1-MCP, effectively prevented superficial scald development and alpha-farnesene production without affecting fruit ripening. Moreover, lovastatin stimulated an increased production of ethanol and oleic + cis vaccenic acid (18:1), both compounds being also involved in cold stress tolerance. In both cultivars, and in contrast to 1-MCP, lovastatin did not impair the expression level of the genes devoted to ethylene production (ACO, ACS) and perception (ERS1, ERS2). As a consequence, the expression levels of the genes involved in texture modifications (PG1) and volatile emission (LOX, HPL, ADH and AAT) were maintained in lovastatin-treated samples allowing the fruit to reach an adequate final quality. The results from this study are discussed to highlight the complex regulatory network underlying superficial scald development in different pear cultivars.

关键词： Hexagonal boron nitride   Rat   Serum   Cytotoxicity   Oxidative stress  

摘要： The aim of our study is to investigate the dose-dependent biological system effect of hexagonal boron nitride (hBN) nanoparticles, which is directly produced nanoscale, in vivo. Wistar albino rats (n = 80) weighing 200-250 g were divided into eight groups (n = 10). The acute effects of hBN NPs (i.v) on the rats were investigated by measuring the biochemical, hematological parameters and oxidant-antioxidant status. The results show that no significant change was observed in the hematological and biochemical parameters when the control group and other low dose groups were compared, except for the 1600 and 3200 mu g/kg b.w. dose groups. Histological detection indicated that 1600 and 3200 mu g/kg hBN NPs treatment could induce significant damage in the liver, kidney, heart, spleen and pancreas. With the findings obtained, it can be seen that hBN NPs cannot be evaluated independently of particle morphology, and that the hBN NPs used in this study may be suitable for biomedical applications where low doses between 50 and 800 mu g/kg are not toxic.

关键词： drought resistance   lipids   photosynthetic pigments   productivity   proline   proteins   Solanum tuberosum  

摘要： Abstract: Interrelation between the morphology, physiology, biochemistry, and productivity of potato plants was shown for the first time using the example of a mid-season-ripening variety (v.) Siversky and a mid-early Tretyakovka v. The yield of Siversky v. turned out to be 1.6 times higher than the yield of Tretyakovka. Aboveground biomass of Siversky v. was distinguished by an increased content of photosynthetic pigments, a greater variability of the protein and lipid metabolism indicators, and more intense oxidation processes and antioxidant protection, which can be the key to its greater productivity. Multivariate statistical analysis showed that the greatest relationship in the climatic conditions of central Russia in 2020 was found for productivity and such indicators as the stomata number per unit leaf area, the number of stems, and the content of pigments, phospholipids, neutral lipids, and water-soluble part of the protein. Thus, both morphological and physiological–biochemical properties can influence the course and direction of the production process, and, hence, the yield of a certain variety. © 2021, Pleiades Publishing, Ltd.

关键词： VDR polymorphisms   cardiometabolic disorders   vitamin D   Tetra ARMS PCR  

摘要： 0072

关键词： Raman spectroscopy   Bacteria chemistry   Discriminant analysis   Analysis of variance (ANOVA)   Partial least squares  

摘要： This study aimed to evaluate the differences in the Raman spectra of nine clinical species of bacteria isolated from infections (three Gram-positive and six Gram-negative species), correlating the spectra with the chemical composition of each species and to develop a classification model through discriminant analysis to categorize each bacterial strain using the peaks with the most significant differences. Bacteria were cultured in Mueller Hinton agar and a sample of biomass was harvested and placed in an aluminum sample holder. A total of 475 spectra from 115 different strains were obtained through a dispersive Raman spectrometer (830 nm) with exposure time of 50 s. The intensities of the peaks were evaluated by one-way analysis of variance (ANOVA) and the peaks with significant differences were related to the differences in the biochemical composition of the strains. Discriminant analysis based on quadratic distance applied to the peaks with the most significant differences and partial least squares applied to the whole spectrum showed 89.5% and 90.1% of global accuracy, respectively, for classification of the spectra in all the groups. Raman spectroscopy could be a promising technique to identify spectral differences related to the biochemical content of pathogenic microorganisms and to provide a faster diagnosis of infectious diseases.

关键词： Acetaminophen   Paracetamol   Carcinogenicity   Metabolism   Genotoxicity   Mutagenicity   Toxicity   Mechanisms  

摘要： In 2019 California's Office of Environmental Health Hazard Assessment (OEHHA) initiated a review of the carcinogenic hazard potential of acetaminophen. In parallel with this review, herein we evaluated the mechanistic data related to the steps and timing of cellular events following therapeutic recommended (<= 4 g/day) and higher doses of acetaminophen that may cause hepatotoxicity to evaluate whether these changes indicate that acetaminophen is a carcinogenic hazard. At therapeutic recommended doses, acetaminophen forms limited amounts of N-acetyl-p-benzoquinone-imine (NAPQI) without adverse cellular effects. Following overdoses of acetaminophen, there is potential for more extensive formation of NAPQI and depletion of glutathione, which may result in mitochondrial dysfunction and DNA damage, but only at doses that result in cell death - thus making it implausible for acetaminophen to induce the kind of stable, genetic damage in the nucleus indicative of a genotoxic or carcinogenic hazard in humans. The collective data demonstrate a lack of a plausible mechanism related to carcinogenicity and are consistent with rodent cancer bioassays, epidemiological results reviewed in companion manuscripts in this issue, as well as conclusions of multiple international health authorities.

关键词： Mathematical modeling   Biochemical networks   Eccentricity-based topological indices   Topological indices of hypertrees   Corona product of graphs  

摘要： We have obtained graph-theoretically based topological indices for the characterization of certain graph theoretical networks of biochemical interest. We have derived certain distance, degree and eccentricity based topological indices for various k-level hypertrees and corona product of hypertrees. We have also pointed out errors in a previous study. The validity of our results is supported by computer codes for the respective indices. Several biochemical applications are pointed out.

关键词： Oxidoreductase   NAD(+)   Maximum reaction rate   Michaelis constant   Turnover number   Evolutionary ancestry   Esterase activity  

摘要： Four phenylacetaldehyde dehydrogenases (designated as FeaB or StyD) originating from styrene-degrading soil bacteria were biochemically investigated. In this study, we focused on the Michaelis-Menten kinetics towards the presumed native substrate phenylacetaldehyde and the obviously preferred co-substrate NAD(+). Furthermore, the substrate specificity on four substituted phenylacetaldehydes and the co-substrate preference were studied. Moreover, these enzymes were characterized with respect to their temperature as well as long-term stability. Since aldehyde dehydrogenases are known to show often dehydrogenase as well as esterase activity, we tested this capacity, too. Almost all results showed clearly different characteristics between the FeaB and StyD enzymes. Furthermore, FeaB from Sphingopyxis fribergensis Kp5.2 turned out to be the most active enzyme with an apparent specific activity of 17.8 +/- 2.1 U mg(-1). Compared with that, both StyDs showed only activities less than 0.2 U mg(-1) except the overwhelming esterase activity of StyD-CWB2 (1.4 +/- 0.1 U mg(-1)). The clustering of both FeaB and StyD enzymes with respect to their characteristics could also be mirrored in the phylogenetic analysis of twelve dehydrogenases originating from different soil bacteria.