Occurrence Of Rearrangements Research Articles

Frontispiece: Rearrangements in Scholl Reaction

The occurrence of rearrangements in Scholl reaction, against anticipated oxidative coupling, results in serendipitous products. Such rearrangements are noticed to arise, either under Lewis/Brønsted acid condition alone or its combination with an oxidant, for substrates of various design. The products formed are majorly due to alkyl/aryl migrations, rearrangement followed by cyclization, and skeletal rearrangements. This review (https://doi.org/10.1002/chem.202103530) showcases all these aspects, besides highlighting the evolving methods to arrest rearrangements in Scholl reaction.

Comparative Analysis of Mitochondrial Genomes in Two Subspecies of the Sunwatcher Toad-Headed Agama (Phrynocephalus helioscopus): Prevalent Intraspecific Gene Rearrangements in Phrynocephalus.

Intraspecific rearrangements of mitochondrial genomes are rarely reported in reptiles, even in vertebrates. The sunwatcher toad-headed agama, Phryncoephalus helioscopus, can serve as an excellent model for investigating the dynamic mitogenome structure at intraspecific level. To date, seven subspecies of P. helioscopus are well recognized, but little is known about the mitogenomic evolution among different subspecies. In this study, complete mitogenomes of subspecies P. helioscopus varius II and P. helioscopus cameranoi were determined by next-generation sequencing, and another P. helioscopus varius I retrieved from GenBank was compiled for comparative analysis. The nucleotide composition and the codon usage are similar to those previously published from toad-headed agamas. P. helioscopus varius II and P. helioscopus cameranoi have 23 tRNA genes, including standard 22 tRNA genes and one extra tRNA-Phe (tRNA-Phe duplication). Gene order and phylogenetic analyses in the genus Phrynocephalus support prevalent intraspecific gene rearrangement in P. helioscopus and other congener species including P. erythrurus, P. vlangalii, and P. forsythii. Six different mitochondrial gene arrangements are observed in Phrynocephalus. Overall, the occurrence of rearrangements may result from multiple independent structural dynamic events. The split of the two subspecies in P. helioscopus was dated at approximately 2.34 million years ago (Ma). Two types of gene rearrangements are found in the three mitogenomes of P. helioscopus, and this intraspecific rearrangement phenomenon can be explained by the tandem duplication/random loss (TDRL) model. Post duplication, the alternative loss types can occur in 0.23–0.72 Ma, suggesting that the duplication and fixation of these rearrangements can occur quite quickly. These findings highlight the need for more mitogenomes at the population level in order to better understand the potentially rampant intraspecific mitogenomic reorganization in Phrynocephalus.

Sructural rearrangements of NTRK genes: characteristics, methods of detection and targeted therapy for cancer

Background. The first-generation trk inhibitors, larotrectinib and entrectinib, were approved by the u.s. Food and drug administration (Fda) for the treatment of advanced solid tumors harboring NTRK gene fusions in November 2018 and in august 2019, respectively. The purpose of the study was to present upto-date data on the structure and functions of ntrk genes, the frequency of occurrence of rearrangements with their participation, the consequences of their occurrence at the cellular level, methods of detecting such rearrangements, as well as targeted drugs used in the presence of chimeric NTRK genes. Material and methods. A systemic literature search was conducted in pubmed ncbi, Web of science, scopus databases. Results. The products of NTRK genes are receptors for neurotrophins, and their high expression is normally observed only in a narrow range of tissue types. Intrachromosomal or interchromosomal rearrangements lead to a significant increase in the level of expression of the chimeric gene regulated by the strong promoter of the partner gene. The high transcriptional activity of such a gene, along with the constant activation of the kinase activity of the protein product, leads to the activation of metabolic pathways responsible for cell escape from apoptosis and disruption of the regulation of the cell cycle. The occurrence of chimeric NTRK genes varies between different types of tumors, with the highest (up to 90 %) in rare cancers (secretory carcinoma of the breast, secretory carcinoma of the salivary glands, congenital mesoblastic nephroma, children’s fibrosarcoma). Larotrectinib and entrectinib are highly effective targeted drugs in suppressing the growth of a tumor carrying NTRK rearrangements, regardless of the type of tumor. In this regard, the introduction of new high-precision methods for the detection of chimeric NTRK genes, as well as the study of the mechanisms of the development of resistance with the assumption of ways to overcome it, seems relevant. Conclusion. Rearrangements of NTRK genes are quite common in various types of oncology and are an effective target for modern targeted drugs.

Analysis of multiple chromosomal rearrangements in the genome of Willisornis vidua using BAC-FISH and chromosome painting on a supposed conserved karyotype

BackgroundThamnophilidae birds are the result of a monophyletic radiation of insectivorous Passeriformes. They are a diverse group of 225 species and 45 genera and occur in lowlands and lower montane forests of Neotropics. Despite the large degree of diversity seen in this family, just four species of Thamnophilidae have been karyotyped with a diploid number ranging from 76 to 82 chromosomes. The karyotypic relationships within and between Thamnophilidae and another Passeriformes therefore remain poorly understood. Recent studies have identified the occurrence of intrachromosomal rearrangements in Passeriformes using in silico data and molecular cytogenetic tools. These results demonstrate that intrachromosomal rearrangements are more common in birds than previously thought and are likely to contribute to speciation events. With this in mind, we investigate the apparently conserved karyotype of Willisornis vidua, the Xingu Scale-backed Antbird, using a combination of molecular cytogenetic techniques including chromosome painting with probes derived from Gallus gallus (chicken) and Burhinus oedicnemus (stone curlew), combined with Bacterial Artificial Chromosome (BAC) probes derived from the same species. The goal was to investigate the occurrence of rearrangements in an apparently conserved karyotype in order to understand the evolutionary history and taxonomy of this species. In total, 78 BAC probes from the Gallus gallus and Taeniopygia guttata (the Zebra Finch) BAC libraries were tested, of which 40 were derived from Gallus gallus macrochromosomes 1–8, and 38 from microchromosomes 9–28.ResultsThe karyotype is similar to typical Passeriformes karyotypes, with a diploid number of 2n = 80. Our chromosome painting results show that most of the Gallus gallus chromosomes are conserved, except GGA-1, 2 and 4, with some rearrangements identified among macro- and microchromosomes. BAC mapping revealed many intrachromosomal rearrangements, mainly inversions, when comparing Willisornis vidua karyotype with Gallus gallus, and corroborates the fissions revealed by chromosome painting.ConclusionsWillisornis vidua presents multiple chromosomal rearrangements despite having a supposed conservative karyotype, demonstrating that our approach using a combination of FISH tools provides a higher resolution than previously obtained by chromosome painting alone. We also show that populations of Willisornis vidua appear conserved from a cytogenetic perspective, despite significant phylogeographic structure.

Моделирование динамического мозаицизма по кольцевым хромосомам в фибробластах и ИПСК человека

Митотическая нестабильность кольцевых хромосом может приводить к появлению клеточных клонов с различной генетической структурой. В качестве модели нестабильности кольцевых хромосом в митозе мы использовали фибробласты от пациентов с r(8), r(13), r(18) и r(22) и полученные из них индуцированные плюрипотентные стволовые клетки (ИПСК). Линии ИПСК с r(22) имели относительно стабильный кариотип на протяжении десятков (до 60) пассажей и сохраняли неизменную структуру кольцевой хромосомы. Кариотип линий ИПСК с r(8) и r(18) на ранних пассажах стабильный, планируется его изучение на поздних пассажах. Наибольшее разнообразие кариотипа выявлено в линиях ИПСК с r(13), в которых наблюдали различные перестройки и выраженную клеточную гетерогенность. Определение факторов, влияющих на митотическую стабильность кольцевых хромосом, может иметь значение для консультирования пациентов. Mitotic instability of ring chromosomes can lead to the appearance of cell clones with different genetic structure. IPSCs from fibroblasts of patients with r(8), r(13), r(18), and r(22) were used as a model of ring chromosomes mitotic behavior. Karyotypes of iPSC lines with r(8) and r(18) have so far been evaluated only in the early passages, lines with r(22) have maintained a relatively stable karyotype up to 60 passages. The occurrence of rearrangements and cellular heterogeneity was found characteristic for r(13) iPSCs. The determination of factors affecting the ring chromosomes mitotic stability would be beneficial for the patient’s prognosis.

Rotavirus A in wild and domestic animals from areas with environmental degradation in the Brazilian Amazon.

Acute gastroenteritis is one of the main causes of mortality in humans and young animals. Domestic and mainly wild animals such as bats, small rodents and birds are highly diversified animals in relation to their habitats and ecological niches and are widely distributed geographically in environments of forest fragmentation in some areas of the Amazon, being considered important sources for viruses that affect humans and other animals. Due to the anthropical activities, these animals changed their natural habitat and adapted to urbanized environments, thus representing risks to human and animal health. Although the knowledge of the global diversity of enteric viruses is scarce, there are reports demonstrating the detection of rotavirus in domestic animals and animals of productive systems, such as bovines and pigs. The present study investigated the prevalence of Rotavirus A in 648 fecal samples of different animal species from the northeastern mesoregion of the state of Pará, Brazil, which is characterized as an urbanized area with forest fragments. The fecal specimens were collected from October 2014 to April 2016 and subjected to a Qualitative Real-Time Polymerase Chain Reaction (RT-qPCR), using the NSP3 gene as a target. It was observed that 27.5% (178/648) of the samples presented positive results for RVA, with 178 samples distributed in birds (23.6%), canines (21.35%), chiropterans (17.98%), bovines (14.6%), horses (8.43%), small rodents (6.74%), pigs (3.93%) and felines (3.37%), demonstrating the circulation of RVA in domestic animals and suggesting that such proximity could cause transmissions between different species and the occurrence of rearrangements in the genome of RVA as already described in the literature, associated to the traces of environmental degradation in the studied areas.

Karyomorphological studies in Mucuna of India

Mucuna Adans. is a large genus with more than 150 species of annual and perennial legumes of pantropical distribution. Despite considerable economic importance of some of its species, almost no work has been done on their cytogenetic characterization in any part of World. In this paper, we have presented a first report on karyomorphological analysis in four Indian species viz., Mucuna atropurpurea, Mucuna monosperma, Mucuna nigricans and Mucuna pruriens bringing out diploid number for M. atropurpurea and karyotypic formula for all the four species. Root tips were treated with 0.002 M 8-hydroxyquinoline and temporary preparations were made after squash in aceto-carmine. Karyomorphological description for each of the species has been detailed taking into account the following features: chromosome number, total length and relative length, arm ratio of each chromosome, haploid set length and degree of asymmetry. Mitotic metaphases in all the species showed 2n=22 chromosomes. Mucuna nigricans showed two pairs of sat-chromosomes. None of the species, however, revealed identical karyotypic formula indicating occurrence of rearrangements. The haploid set length of annual M. pruriens was found to be reduced in size when compared to perennial species pointing its evolution from the latter.

Influence of genetic background on the occurrence of chromosomal rearrangements in Saccharomyces cerevisiae

BackgroundChromosomal rearrangements such as duplications and deletions are key factors in evolutionary processes because they promote genomic plasticity. Although the genetic variations in the Saccharomyces cerevisiae species have been well documented, there is little known to date about the impact of the genetic background on the appearance of rearrangements.ResultsUsing the same genetic screening, the type of rearrangements and the mutation rates observed in the S288c S. cerevisiae strain were compared to previous findings obtained in the FL100 background. Transposon-associated rearrangements, a major chromosomal rearrangement event selected in FL100, were not detected in S288c. The mechanisms involved in the occurrence of deletions and duplications in the S288c strain were also tackled, using strains deleted for genes implicated in homologous recombination (HR) or non-homologous end joining (NHEJ). Our results indicate that an Yku80p-independent NHEJ pathway is involved in the occurrence of these rearrangements in the S288c background.ConclusionThe comparison of two different S. cerevisiae strains, FL100 and S288c, allowed us to conclude that intra-species genomic variations have an important impact on the occurrence of chromosomal rearrangement and that this variability can partly be explained by differences in Ty1 retrotransposon activity.

Heat-Induced Gel Formation by Soy Proteins at Neutral pH

Heat-induced gel formation by soy protein isolate at pH 7 is discussed. Different heating and cooling rates, heating times, and heating temperatures were used to elucidate the various processes that occur and to study the relative role of covalent and noncovalent protein interactions therein. Gel formation was followed by dynamic rheological measurements. Heat denaturation was a prerequisite for gel formation. The gelation temperature (84 degrees C) was just above the onset denaturation temperature of glycinin. The stiffness of the gels, measured as the elastic modulus, G', increased with the proportion of denatured protein. An increase in G' was also observed during prolonged heating at 90 degrees C. This increase is explained by the occurrence of rearrangements in the network structure and probably also by further incorporation of protein in the network. The increase in G' upon cooling was thermoreversible indicating that disulfide bond formation and rearrangements do not occur upon cooling.

The importance of distinct metabolites of N-nitrosodiethylamine for its in vivo mutagenic specificity

Although N-nitrosodiethylamine (NDEA) is a potent carcinogen in rodents and a probable human carcinogen, little attempts were made to characterize its mutation spectrum in higher eukaryotes. We have compared forward mutation frequencies at multiple (700) loci with the mutational spectrum induced at the vermilion gene of Drosophila, after exposure of post- and pre-meiotic male germ cells to NDEA. Among 30 vermilion mutants collected from post-meiotic stages were 12 G:C→A:T transitions (40%), 8 A:T→T:A transversions (27%), and 4 structural rearrangements (13%). The remainder were three A:T→G:C transitions, two G:C→C:G transversions and one G:C→T:A transversion. The results show that although NDEA induces predominantly transitions (40% G:C→A:T and 10% A:T→G:C), the frequencies of transversions (37%, of which 27% of A:T→T:A transversions) and especially of rearrangements (13%) are remarkably high. This mutation spectrum differs significantly from that produced by the direct-ethylating agent N-ethylnitrosourea (ENU), although the relative distribution of ethylated DNA adducts is similar for both carcinogens. These differences, in particular the occurrence of rearrangements, are most likely the result of the requirement of NDEA for bioactivation. Since all four rearrangements were collected from non-metabolizing spermatozoa (or late spermatids), it is hypothesized that they derived from acetaldehyde, a stable metabolite of NDEA. Due to its cytotoxicity, attempts to isolate vermilion mutants from NDEA-exposed pre-meiotic cells were largely unsuccessful, because only two mutants (one A:T→G:C transition and one 1 bp insertion) were collected from those stages. Our results show that NDEA is capable of generating carcinogenic lesions other than base pair substitutions.

Search for Rearrangements and/or Allelic Loss of the fas/APO-1 Gene in 101 Human Lymphoma

The authors analyzed the possible occurrence of rearrangements and/or allelic loss of the fas/APO-1 gene in a representative series of human lymphomas, including 101 cases of Hodgkin's disease (HD) and non-Hodgkin's lymphomas (NHL). The rationale for this study was double. Chromosome 10 alterations, frequently observed in lymphoma subtypes, encompass the chromosomal localization of fas/APO-1. In addition, Ipr mouse mutants, which present with a generalized lymphoproliferative disease, were shown to exhibit alterations of fas/APO-1 structure and expression. In this retrospective study, the authors performed gene dosage of fas/APO-1 by Southern blots. No fas/APO-1 alterations were observed in the 31 HD cases. Among 70 T-cell and B-cell NHL, allelic loss of fas/APO-1 was observed in three cases. Two cases with different clinical, phenotypic, and histologic presentations showed a rearrangement of fas/APO-1. A third case showed amplification. Thus fas/APO-1 alterations do occur in human lymphomas, although at a relatively low frequency.

A Cytotaxonomic Study in Twelve Brazilian Taxa of Stylosanthes Sw., Leguminosae.

The karyotypes of twelve diploid taxa (2n=20) of the Stylosanthes, Leguminosae, were analysed. The genus has a very conservative karyological pattern. The comparison among taxa belonging to the controversial S. guiananesis species complex, showed clear differences in size of their chromosome complements and morphology, which suggest that this group is under a process of chromosome evolution by the occurrence of rearrangements and changes in DNA content. The analysis of four species unrelated to this complex showed clear differences among their karyotypes.

Genomic rearrangements and tumor-forming potential in an SV40-transformed mouse cell line and its hybrid and cybrid progeny.

The mechanism by which DNA tumor viruses transform cells is attributed to the actions of viral gene products, the T antigens (Tooze 1980). Very little attention has been paid to changes in the host genome that may precede, accompany, or follow integration of the viral genome and contribute to the transformation phenotype. The existence of prior mutations that facilitate transformation is suggested by the very low yields of transformed clones and the wide spectrum of phenotypes seen in SV40-transformed mouse cells (see, e.g., Scher and Nelson-Rees 1971). With respect to genomic changes occurring after viral integration, autonomous replication of integrated viral sequences has not been seen in nonpermissive cells, nor has the occurrence of rearrangements been noted subsequent to integration (Botchan et al. 1979, 1980; Sambrook et al. 1980). Indeed, the integrated viral genome, whether defective or not, has been considered a stable part of the host genome in nonpermissive...

Thermal rearrangement of O-methyleneamino thiocarbamates

The rate of the thermal, uncatalysed, [1,3] rearrangement of aromatic O-methyleneamino thiocarbamates to S-methyleneamino thiocarbamates in solution is insensitive to changes in both solvent polarity and substituent on ring and imino-carbon atoms, suggesting a transition state involving little charge separation. The occurrence of rearrangement via a radical pair is suggested by the detection by e.s.r. spectroscopy of aromatic iminyls, generated as transients during rearrangement.

Studies in the norbornene series. Part II. Synthesis and reactions of some norbornanes carrying fused heterocycles

Some norbornanes carrying fused heterocycles have been synthesised by 1,3-dipolar additions to substituted norbornenes. Attempts to prepare heterocycles by reactions of electrophilic reagents with the strained double bond in norbornenes were unsuccessful owing to the occurrence of rearrangements. In the reaction of iodine with 5-endo-aminomethylnorborn-2-ene, rearrangement may be prevented by prior nucleophilic attack of the amine group on the cation intermediate to give a 5-azatricyclo[4.2.1.0]nonane (32).

Synthesis of pyrazolines by the condensation of monoalkyl hydrazones with aldehydes

Acetaldehyde readily condenses with its monalkyl hydrazones with the formation of 1-alkyl-5-methyl-2-pyrazolines. A number of pure 2pyrazolines have been synthesized in this way with yields of 40–60%. In the condensation of propionaldehyde with its isopropyl hydrazone, because of the occurrence of rearrangements and the nonstereospecificity of the process, a mixture of structural and stereoisomeric 2-pyrazolines is formed. The promising condensation of aldehydes with monalkyl hydrazones of other aldehydes and ketones is accompanied by “transhydrazonation,” which limits the preparative possibilities of this reaction.

A Study of Plasmochin and the Occurrence of Rearrangements in the Preparation of Certain Plasmochin Analogs1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Study of Plasmochin and the Occurrence of Rearrangements in the Preparation of Certain Plasmochin Analogs1Robert C. Elderfield, Lyman C. Craig, Walter M. Lauer, Richard T. Arnold, Walter J. Gensler, James D. Head, Thomas H. Bembry, Harold R. Mighton, John Tinker, Jean Galbreath, Ann D. Holley, Leon Goldman, John T. Maynard, and Norman PicusCite this: J. Am. Chem. Soc. 1946, 68, 8, 1516–1523Publication Date (Print):August 1, 1946Publication History Published online1 May 2002Published inissue 1 August 1946https://doi.org/10.1021/ja01212a039RIGHTS & PERMISSIONSArticle Views121Altmetric-Citations16LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (847 KB) Get e-Alerts Get e-Alerts