СРАВНИТЕЛЬНАЯ ХАРАКТЕРИСТИКА РАЗЛИЧНЫХ ВАРИАНТОВ КОЛИЧЕСТВЕННОГО ХРОМАТОГРАФИЧЕСКОГО АНАЛИЗА МЕТОДОМ ДВОЙНОЙ СТАНДАРТНОЙ ДОБАВКИ

Different algorithms for processing the quantitative gas chromato­gra­­phic ana­lysis data using the double standard addition method are compared for their accuracy. Three principal approaches are possible for such processing: I – simple comparison of values determined by sing­le and double standard additions, II – approximation of «peak area of ana­lyte» (S) – «mass of standard addition» (madd) depen­den­ce by the least squa­res method [linear reg­res­sion, m(S)], and III – independent quantification of analyte with both standard additi­ons follo­wed by the linear extrapolation of two sub-results on the so-cal­led «zero standard addi­tion», mx(madd ® 0). It is concluded that the quantitation results obtained using the various modes of the method are comparable in accuracy, but somewhat underestimated relative to the specified amounts of analytes. The principal reason of such systematic errors is the eva­po­ration of the solvent during the successive injecting of the same samples into the gas chroma­to­graph. Due to this reason the peak are­as, measured after the standard addition, appear to be slight­­ly increased and this leads to the systematic underestimation of the results. The second (less impor­tant) factor is the small increa­se of the samp­le volumes due to the addition of the compo­nents to be determined. It is confirmed that the systematic errors of different modes of standard addition are not exceeding the values of their random uncertainties. The op­ti­mal results (considering their signs of deviations) are provided using the double standard addition method with extrapolation of sub-results on «zero standard addition». In order to exclude the possible influence of «human factor» (increasing the re­sults precision during the series of analyses of similar samples due to the rising experience of analytical chemists) all parallel measurements have been per­for­med by bachelor students of  the Chemistry Ins­titute of  the St. Petersburg State University in the course of their laboratory practical works in chromatography. Such organization of experiments increases their credibility as it excluded the dependence of the results on the qualification of chemists.Keywords: Quantitative chromatographic analysis, double standard addition, different kinds of data processing, «human factor» for parallel measurementsDOI: http://dx.doi.org/10.15826/analitika.2021.25.2.010 Igor G. Zenkevich, Darina D. Barkhatova, Maria N. Belysheva, Nikita A. Kaminskii, Elizabet M. Karchuganova, Anastasia V. Klaving, Alexander A. Kovalenko, Vasilisa S. Krivovicheva, Artem A. Kuz’min, Maria V. Mel’nik, Polina S. Paramonova, Roman A. Popov, Vassylii V. Potapenkov, Artem A. Rashevskii, Alexandra A. Sysoeva, Irina I. Fedorova, Andrew A. Firsov St. Petersburg State University, Institute for Chemistry, Universitetskii prosp., 26,St. Petersburg 198504, Russian FederationРазличные варианты обработки результатов количественного газохроматогра­фи­ческого анализа способом двойной стандартной добавки сопоставлены по точно­сти. Три основных из них: I – простое сравнение данных, получаемых с использо­ва­нием однократной и двойной добавок, II – аппрокси­ма­ция зависимости m(S) в ко­ор­динатах «площадь пика оп­ре­де­ляемого компонента» (S) – «масса добав­ки» (mдоб) методом наименьших квадратов по уравнению линей­ной регрессии и III–вычис­ле­ние количеств определяемых компонентов (mx) по каж­­дой из стандарт­ных до­ба­вок с последующей линейной экстраполяцией их зна­чений на «ну­ле­вую» стан­дар­т­ную до­­бавку, mx(mдоб® 0). Показано, что результаты определений в различ­ных ва­ри­ан­­тах стандартных добавок сопоставимы по точно­с­ти, но несколько за­ни­жены относительно за­дан­ных количеств аналитов. Главной причиной таких сис­те­мати­чес­ких погрешностей яв­ляется испарение рас­тво­рителя при по­следовательном до­зи­рова­нии проб од­них и тех же образ­цов в хро­матограф. В резу­ль­тате площади пи­ков, оп­ределяемые после ввода стандартных добавок в образцы, ока­зываются не­ск­о­ль­ко за­вышенными, что и приводит к зани­же­нию результатов. Второй (менее зна­чи­мый) фактор – не­­зна­читель­ное уве­ли­чение объема образцов за счет добавок оп­ре­деляе­мых компо­нентов. Отмечено, что погрешности определений раз­личными вари­ан­тами способа стандартной добавки не превышают слу­чайных сос­та­в­ля­ю­щих по­гре­ш­­но­с­тей. Лучшие результаты (с учетом знаков отклонений) обеспечивает вы­чи­с­ле­ние соде­р­жа­­ния определяемого аналита методом двойной стандартной добавки с экстраполя­ци­ей результатов на «нулевую» вели­чину добавки. Для исключения влияния «человеческого фактора» (увеличение то­чности ре­зу­льтатов в ходе анализа серий однотипных образцов за счет опыта ана­литиков) все параллельные опреде­ле­ния были про­ве­дены студентами бакалав­ри­ата Института химии Санкт-Петер­бург­ского государ­ст­венного университета в ходе выполнения ими лабораторных работ. Такая орга­низация экспериментов повышает их дос­то­верность, поскольку исключает зависимость результатов от раз­личий в ква­ли­фи­ка­ции аналити­ков.Ключевые слова: Количественный хроматографический анализ, способ двойной стандартной добавки, различные варианты обработки результатов, особенности па­рал­­лель­ных определений.DOI: http://dx.doi.org/10.15826/analitika.2021.25.2.01

Genomic analyses inform on migration events during the peopling of Eurasia.

High-coverage whole-genome sequence studies have so far focused on a limited number of geographically restricted populations, or been targeted at specific diseases, such as cancer. Nevertheless, the availability of high-resolution genomic data has led to the development of new methodologies for inferring population history and refuelled the debate on the mutation rate in humans. Here we present the Estonian Biocentre Human Genome Diversity Panel (EGDP), a dataset of 483 high-coverage human genomes from 148 populations worldwide, including 379 new genomes from 125 populations, which we group into diversity and selection sets. We analyse this dataset to refine estimates of continent-wide patterns of heterozygosity, long- and short-distance gene flow, archaic admixture, and changes in effective population size through time as well as for signals of positive or balancing selection. We find a genetic signature in present-day Papuans that suggests that at least 2% of their genome originates from an early and largely extinct expansion of anatomically modern humans (AMHs) out of Africa. Together with evidence from the western Asian fossil record, and admixture between AMHs and Neanderthals predating the main Eurasian expansion, our results contribute to the mounting evidence for the presence of AMHs out of Africa earlier than 75,000 years ago.Support was provided by: Estonian Research Infrastructure Roadmap grant no 3.2.0304.11-0312; Australian Research Council Discovery grants (DP110102635 and DP140101405) (D.M.L., M.W. and E.W.); Danish National Research Foundation; the Lundbeck Foundation and KU2016 (E.W.); ERC Starting Investigator grant (FP7 - 261213) (T.K.); Estonian Research Council grant PUT766 (G.C. and M.K.); EU European Regional Development Fund through the Centre of Excellence in Genomics to Estonian Biocentre (R.V.; M.Me. and A.Me.), and Centre of Excellence for Genomics and Translational Medicine Project No. 2014-2020.4.01.15-0012 to EGC of UT (A.Me.) and EBC (M.Me.); Estonian Institutional Research grant IUT24-1 (L.S., M.J., A.K., B.Y., K.T., C.B.M., Le.S., H.Sa., S.L., D.M.B., E.M., R.V., G.H., M.K., G.C., T.K. and M.Me.) and IUT20-60 (A.Me.); French Ministry of Foreign and European Affairs and French ANR grant number ANR-14-CE31-0013-01 (F.-X.R.); Gates Cambridge Trust Funding (E.J.); ICG SB RAS (No. VI.58.1.1) (D.V.L.); Leverhulme Programme grant no. RP2011-R-045 (A.B.M., P.G. and M.G.T.); Ministry of Education and Science of Russia; Project 6.656.2014/K (S.A.F.); NEFREX grant funded by the European Union (People Marie Curie Actions; International Research Staff Exchange Scheme; call FP7-PEOPLE-2012-IRSES-number 318979) (M.Me., G.H. and M.K.); NIH grants 5DP1ES022577 05, 1R01DK104339-01, and 1R01GM113657-01 (S.Tis.); Russian Foundation for Basic Research (grant N 14-06-00180a) (M.G.); Russian Foundation for Basic Research; grant 16-04-00890 (O.B. and E.B); Russian Science Foundation grant 14-14-00827 (O.B.); The Russian Foundation for Basic Research (14-04-00725-a), The Russian Humanitarian Scientific Foundation (13-11-02014) and the Program of the Basic Research of the RAS Presidium “Biological diversity” (E.K.K.); Wellcome Trust and Royal Society grant WT104125AIA & the Bristol Advanced Computing Research Centre (http://www.bris.ac.uk/acrc/) (D.J.L.); Wellcome Trust grant 098051 (Q.A.; C.T.-S. and Y.X.); Wellcome Trust Senior Research Fellowship grant 100719/Z/12/Z (M.G.T.); Young Explorers Grant from the National Geographic Society (8900-11) (C.A.E.); ERC Consolidator Grant 647787 ‘LocalAdaptatio’ (A.Ma.); Program of the RAS Presidium “Basic research for the development of the Russian Arctic” (B.M.); Russian Foundation for Basic Research grant 16-06-00303 (E.B.); a Rutherford Fellowship (RDF-10-MAU-001) from the Royal Society of New Zealand (M.P.C.)

Quercetin isolated from Hedysarum neglectum Ledeb. as a preventer of metabolic diseases

Diseases associated with metabolic disorders seem to affect more and more people worldwide. Biologically active supplements may prevent or relieve metabolic disorders. Quercetin is known for its potential to inhibit metabolic syndrome. This paper introduces an in vivo experiment on rodents. It featured hypoglycemic, hypocholesterolemic, and hepatotoxic properties of quercetin. Quercetin was obtained from the hairy root extract of Hedysarum neglectum Ledeb. Two doses (50 and 100 mg/kg) were used to evaluate its hypoglycemic potential. Rats with induced diabetes were tested for body weight, glucose, and cholesterol while mice with induced hypercholesterolemia were checked for blood cholesterol changes. Potential biochemical and pathological changes in the liver were also studied on rats. Quercetin treatment caused neither significant health problems nor death in the model animals. It had no effect on body weight, even in the animals with induced diabetes. In addition, quercetin did not increase glucose and cholesterol in the blood and triggered no pathological changes in the liver. Quercetin isolated from H. neglectum hairy root extract demonstrated no hepatotoxicity. Unfortunately, it showed no beneficial effect on cholesterol and glucose levels and had no efficacy against metabolic syndrome. Further research is needed to assess the effect of quercetin on other metabolic markers, e.g., genes associated with the metabolism of lipids, carbohydrates, etc

Complete mitochondrial genome sequence of the “copper moss” Mielichhoferia elongata reveals independent nad7 gene functionality loss

The mitochondrial genome of moss Mielichhoferia elongata has been sequenced and assembled with Spades genome assembler. It consists of 100,342 base pairs and has practically the same gene set and order as in other known bryophyte chondriomes. The genome contains 66 genes including three rRNAs, 24 tRNAs, and 40 conserved mitochondrial proteins genes. Unlike the majority of previously sequenced bryophyte mitogenomes, it lacks the functional nad7 gene. The phylogenetic reconstruction and scrutiny analysis of the primary structure of nad7 gene carried out in this study suggest its independent pseudogenization in different bryophyte lineages. Evaluation of the microsatellite (simple sequence repeat) content of the M. elongata mitochondrial genome indicates that it could be used as a tool in further studies as a phylogenetic marker. The strongly supported phylogenetic tree presented here, derived from 33 protein coding sequences of 40 bryophyte species, is consistent with other reconstructions based on a number of different data sets

The Mitochondrial Genome of Nematodontous Moss Polytrichum commune and Analysis of Intergenic Repeats Distribution Among Bryophyta

An early-branched moss Polytrichum commune is a widely accepted model object for ecological, environmental, physiological, and genetic studies. Its mitochondrial genome has been sequenced and annotated. The genome contains 67 genes in total and has a length equal to 114,831 bp, which exceeds the length of most known mitochondrial genomes for mosses. A phylogenetic tree based on 33 coding sequences of mitochondrial genome was constructed, and the pairwise identity of whole mitogenome sequences was estimated for 44 Bryophyta species. Based on the analysis of pairwise identity, it was shown that mitogenomes of Tetraphis pellucida and Buxbaumia aphylla sufficiently differ from those of other Bryophyta species. The first known Bryophyta mitogenome rearrangement was identified in Pogonatum inflexum within Polytrichopsida. Based on the intergenic repeats occurrence in 44 bryophyte mitochondrial genomes and available data on repetitive elements content in other Viridiplantae groups, it was noted for the first time that greater stability of the moss’s mitogenomes is probably associated mainly with the absence of long (>1 kb) repeats. The phenomenon of absence of the intergenic repetitive elements in the terminal clades species was discovered

New Application of the Commercially Available Dye Celestine Blue B as a Sensitive and Selective Fluorescent “Turn-On” Probe for Endogenous Detection of HOCl and Reactive Halogenated Species

Hypochlorous acid (HOCl) derived from hydrogen peroxide and chloride anion by myeloperoxidase (MPO) plays a significant role in physiological and pathological processes. Herein we report a phenoxazine-based fluorescent probe Celestine Blue B (CB) that is applicable for HOCl detection in living cells and for assaying the chlorinating activity of MPO. A remarkable selectivity and sensitivity (limit of detection is 32 nM), along with a rapid “turn-on” response of CB to HOCl was demonstrated. Furthermore, the probe was able to detect endogenous HOCl and reactive halogenated species by fluorescence spectroscopy, confocal microscopy, and flow cytometry techniques. Hence, CB is a promising tool for investigating the role of HOCl in health and disease and for screening the drugs capable of regulating MPO activity

The CIMP-high phenotype is associated with energy metabolism alterations in colon adenocarcinoma

Abstract Background CpG island methylator phenotype (CIMP) is found in 15–20% of malignant colorectal tumors and is characterized by strong CpG hypermethylation over the genome. The molecular mechanisms of this phenomenon are not still fully understood. The development of CIMP is followed by global gene expression alterations and metabolic changes. In particular, CIMP-low colon adenocarcinoma (COAD), predominantly corresponded to consensus molecular subtype 3 (CMS3, “Metabolic”) subgroup according to COAD molecular classification, is associated with elevated expression of genes participating in metabolic pathways. Methods We performed bioinformatics analysis of RNA-Seq data from The Cancer Genome Atlas (TCGA) project for CIMP-high and non-CIMP COAD samples with DESeq2, clusterProfiler, and topGO R packages. Obtained results were validated on a set of fourteen COAD samples with matched morphologically normal tissues using quantitative PCR (qPCR). Results Upregulation of multiple genes involved in glycolysis and related processes (ENO2, PFKP, HK3, PKM, ENO1, HK2, PGAM1, GAPDH, ALDOA, GPI, TPI1, and HK1) was revealed in CIMP-high tumors compared to non-CIMP ones. Most remarkably, the expression of the PKLR gene, encoding for pyruvate kinase participating in gluconeogenesis, was decreased approximately 20-fold. Up to 8-fold decrease in the expression of OGDHL gene involved in tricarboxylic acid (TCA) cycle was observed in CIMP-high tumors. Using qPCR, we confirmed the increase (4-fold) in the ENO2 expression and decrease (2-fold) in the OGDHL mRNA level on a set of COAD samples. Conclusions We demonstrated the association between CIMP-high status and the energy metabolism changes at the transcriptomic level in colorectal adenocarcinoma against the background of immune pathway activation. Differential methylation of at least nine CpG sites in OGDHL promoter region as well as decreased OGDHL mRNA level can potentially serve as an additional biomarker of the CIMP-high status in COAD