Cytology and Genetics最新文献

The coronavirus disease (COVID-19), which is caused by a severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was for the first time detected in December 2019. At the beginning of the pandemic, it was believed that children are less susceptible to COVID-19 compared to adults, but further studies demonstrated that children are also susceptible to infection with the SARS-CoV-2 virus. In recent years, appeared studies about the role of genetic factors in the course of COVID-19. This fact suggests a possible existence of hereditary predisposition of individuals to infection with the SARS-CoV-2 virus. Recently, data was obtained that certain genetic polymorphisms (particularly, different genotypes for the polymorphic variant rs12979860 of the IFNL gene) can act as predictors of the severe course of respiratory infections in children (particularly, COVID-19). The aim of this work was to study the peculiarities of the genotype distribution for the IFNL gene rs12979860 polymorphism in a cohort of children who suffered from COVID-19 as well as to estimate the association of this polymorphism with a risk of infection with the SARS-CoV-2 virus, the development of pneumonia during the coronavirus disease, and the course of this disease among children with recurrent respiratory infections (RRI). For this purpose, genotyping for the IFNL gene rs12979860 locus polymorphism was carried out in the studied group of 70 children who had a laboratory-confirmed COVID-19. According to the results of the study, it was established that the C allele was more common in children with RRI as compared with those with episodic viral infections (p < 0.05, OR 3.2; CI 1.52–6.71); therefore, this variant can be considered as a risk allele for more frequent viral infections. In addition, the C allele predominated in the subgroup of children with pneumonia (p < 0.05, OR 2.36; CI 1.19–4.68), indicating that the C allele can be considered a risk allele for a more severe course of COVID-19 due to pneumonia. The results obtained suggest that the C allele can act as a predictive marker of the risk of developing pneumonia in children with COVID-19. In addition, the carriage of the C allele is associated with cases of RRI among children.

Using morphological traits and molecular-genetic research methods, the authors have identified 24 species of naked amoeba from natural biotopes. The 18S rRNA gene sequences were obtained for the following species of naked amoeba: Amoeba proteus isolate AP07 (ON907618), Saccamoeba limax isolate SLU_22 (OP894078), Saccamoeba limax isolate SL_Uk19 (OQ520144), Saccamoeba sp. strain IDL777 (MZ079370), Thecamoeba striata isolate THS19 (OQ134482), Thecamoeba striata isolate THS20 (OQ134483), Thecamoeba similis isolate Prut river (OL604177), Thecamoeba similis isolate Baggersee Innsbruck (Baggersee Rossau) (OL604178), Thecamoeba quadrilineata isolate THQD2 (ON398269), Thecamoeba quadrilineata isolate THQA1 (ON398268), Thecamoeba sp. strain THS203 (MZ079371), Stenamoeba stenopodia isolate UKSS7 (OP375108), Stenamoeba stenopodia isolate POLSS7 (OP419588), Korotnevella stella isolate KSD2 (ON398267), Korotnevella stella isolate KSA1 (ON398266), Vexillifera bacillipedes isolate river Dnepr (OK649262), Vannella lata isolate Kamenka river (OL305063), Vannella lata isolate Varta river (OL305064), Vannella sp. strain VLS303 (MZ079372), Vannella simplex isolate Black Sea (OM403052), Vannella simplex isolate Mediterranean Sea (OM403053), Ripella sp. strain RPL100 (MZ079369), Mayorella vespertilioides isolate MV_7 (OP739500), Mayorella sp. isolate MY_7 (OP729930), Acanthamoeba sp. strain ATM123 (MZ079366), Acanthamoeba sp. isolate river Elbe (OK649261), Acanthamoeba polyphaga isolate AcPoly01 (ON908497), Acanthamoeba polyphaga isolate AcPoly15 (ON908496), Acanthamoeba griffini isolate Black sea (OM522832), Acanthamoeba griffini isolate Mediterranean Sea (OM522833), Cochliopodium actinophorum strain COP101 (MZ079367), Cochliopodium minus isolate river Stokhid (OK649264), Cochliopodium sp. strain COP102 (MZ079368), Vahlkampfia avara isolate VA7 (OP179657), Willaertia magna isolate river Teterev (OK649263). All of the naked amoebae species on the phylogenetic tree constructed based on the 18S rRNA gene are located within Amoebozoa and grouped with Tubulinea and Discosea. There are separate groups of freshwater, marine, and terrestrial biotopes; these groups are sister species relative to one another with low results of bootstrap analysis, which shows a low accuracy in the distances of particular amoeba species isolated from different natural biotopes.

Abstract

RNA interference (RNAi) is a new potential tool for plant breeding by introducing small noncoding RNA sequences with the possibility of silencing gene expression in a sequence-specific manner. The ability to decrease the expression of a certain gene provides the possibility of acquiring a new characteristic through the elimination or accumulation of certain plant traits, which leads to biochemical or phenotypic changes that the original plants do not have. A progress (reached over the past decades) in the application of RNAi for the creation of cereal crops with improved economically valuable traits is described in this literature review. The main stages of the mechanism of gene silencing mediated by short interfering RNAs (siRNAs), peculiarities of their biogenesis, mode of action, and distribution are briefly presented. Numerous examples of the development of different biotechnological approaches to the improvement of cereals using gene transformation and exogenous double-stranded RNA (dsRNA) molecules are summarized. The possibilities of using RNAi technology for changing the agronomic traits of plants, increasing the nutritional value and quality of the grain, and reducing the number of toxic compounds and allergens are highlighted. Considerable attention is paid to the practical results of different applications of RNAi to increase the resistance of grain crops to biotic stress factors (particularly, viruses, bacteria, fungi, pest insects, and nematodes). The examples of using siRNA-mediated RNAi to improve the cereal resistance to abiotic stresses (including drought and salinity) are given.

Abstract

Tandemly arranged repetitive regions (repeats) that encode 5S rRNA (5S rDNA) are an indispensable component of eukaryotic genomes. Typically, 5S rDNA repeats within a genome are very similar due to the concerted nature of the evolution of this type of repeats. Each 5S rDNA repeat consists of an evolutionarily conserved coding sequence (CDS) and a variable intergenic spacer (IGS). 5S rDNA is a popular model for studying the molecular evolution of repetitive sequences, and the high rate of IGS mutations determines its wide use in phylogenetic analysis of closely related taxa. Nevertheless, 5S rDNA remains unexplored for many groups of higher plants, especially for the Plumbaginaceae family. Some taxa of this family are endemic to southern Ukraine and listed in the Red Book. However, their taxonomic status is controversial, and its clarification requires the use of molecular phylogenetic methods. In this work, we examined the molecular organization of 5S rDNA for representatives of four genera of the tribe Limonieae, the largest in the family Plumbaginaceae. It was shown that the CDS of 5S rDNA of representatives of the genera Limonium, Armeria, and Ceratolimon possess single mutations that do not affect the formation of the secondary structure of 5S rRNA. In contrast, in the genomes of Goniolimon species, in addition to functionally normal 5S rDNA repeats, numerous pseudogenes were found that do not evolve in a concerted manner and contain numerous mutations in the CDS that disrupt the secondary structure of 5S rRNA. A significant phylogenetic distance between representatives of the subgenera Pteroclados and Limonium of the genus Limonium indicates that Pteroclados can be considered a separate genus. The high rate of molecular evolution makes 5S rDNA IGS a convenient tool for the reconstruction of phylogenetic relationships within the studied genera of the tribe Limonieae and the barcoding of Ukrainian endemics of the genus Limonium.

The Crucifers family (Brassicaceae) includes a large number of economically important crops, particularly Brassica rapa, which is a widely used model plant for molecular genetic studies of oilseeds. B. rapa is a highly polymorphic species that includes many of genetically distinct subspecies. Considering this fact, the intraspecific hybridization of B. rapa subspecies is considered a promising breeding approach aimed at increasing the genetic diversity of the crop. Previously, the authors have shown that one of such hybrids, B. rapa subsp. oleifera f. biennis × (subsp. rapifera × pekinensis), could be a valuable oil feedstock due to its increased productivity. However, obtaining hybrids and their subsequent breeding would require the involvement of various molecular marker systems. So far, the method of estimating the length polymorphism of the first (TBP) and second (cTBP) introns of β-tubulin has demonstrated its high accuracy and reliability in the identification (DNA-barcoding) of flowering plant taxonomic units at different levels. In the present study, the productivity of such hybrid oil tyfon (B. rapa subsp. oleifera f. biennis × (subsp. rapifera × pekinensis)) was evaluated and DNA-barcoding of different hybrid tyfon lines (B. rapa subsp. oleifera f. biennis × (subsp. rapifera × pekinensis)) and its parental B. rapa subspecies using the β-tubulin intron length polymorphism assessment approach was carried out. Based on the data of the molecular genetic analysis, which included the assessment of length polymorphism of the first and second introns of β-tubulin genes, we were able to confirm the origin of the oil tyfon hybrid (B. rapa subsp. oleifera f. biennis × (subsp. rapifera × pekinensis)) hybrid from Dutch leaf tyfon (B. rapa subsp. rapifera × pekinensis) and winter turnip (B. rapa subsp. oleifera) with high confidence. Along with that, it was possible to differentiate var. glabra and var. laxa accession of napa cabbage (B. rapa subsp. pekinensis) for the first time using combined TBP and cTBP analyses. A variation in the number of amplified regions of β-tubulin introns was noted in different genotypes; however, these differences did not appear to be a specific feature of a particular subspecies/hybrid. This suggests that B. rapa hybrids most likely do not differ in ploidy compared to their parental genotypes. In addition, it was shown that the mentioned oil tyfon hybrid lines of Ukrainian breeding show a significant level of morphological variation despite their common breeding pedigree.