Search results for "sister"

Nalidixic acid-resistant V79 cells with reduced DNA topoisomerase II activity and amplification prone phenotype

1992

Spontaneously nalidixic acid-resistant lines (NAr lines) were selected from a V79 Chinese hamster cell line and phenotypically characterized. NAr lines showed an increased doubling time, a higher number of spontaneous SCE, and more interestingly, decreased DNA topoisomerase II activity. These lines were also cross-resistant to the eukaryotic topoisomerase II inhibitors etoposide and adriamycin, but showed the same level of sensitivity as the parental line to the DNA topoisomerase I inhibitor camptothecin. NAr lines were cross-resistant to other drugs, such as PALA, MTX and MPA, resistance to which has been shown to arise by amplification of the target genes. This last feature, together with…

Phylogeny and inflorescences of Berberidaceae — a morphological survey

1995

The 13 genera of Berberidaceae are investigated morphologically and cladistically in order to examine the phylogenetic relationships among the extant taxa. Cladistic analysis of 59 morphological characters using PAUP resulted in one most parsimonious tree. In the present paper main emphasis is put on inflorescence morphological features, which contributes eight characters to the current data matrix. The analysis resulted in four major clades. Nandina has a basal position, and the next clade includes Berberis and Mahonia. Ranzania is sister genus to Jeffersonia, Diphylleia/Podophyllum and Leontice/Bongardia. These all form the sister group to a clade in which Achlys is sister taxon to Epimed…

Melastomeae come full circle: biogeographic reconstruction and molecular clock dating.

2001

Rhexia, with 11 species in the Coastal Plain province of North America, is the only temperate zone endemic of the tropical eudicot family Melastomataceae. It is a member of the only pantropical tribe of that family, Melastomeae. Based on the chloroplast gene ndhF, we use a fossil-calibrated molecular clock to address the question of the geographic origin and age of Rhexia. Sequences from 37 species in 21 genera representing the tribe's geographical range were analyzed together with five outgroups. To obtain better clade support, another chloroplast region, the rpl16 intron, was added for 24 of the species. Parsimony analysis of the combined data and maximum-likelihood analysis of ndhF alone…

Molecular evidence for phylogenetic relationships among buntings and American sparrows (Emberizidae)

2001

To help clarify controversial phylogenetic relationships within the family Emberizidae, we sequenced 1238 bp of mitochondrial DNA from the cytochrome b gene and a flanking portion of ND5. Although the longspurs (Calcarius) and the snow buntings (Plectrophenax) have been grouped with the Old World buntings (Emberiza) in traditional classifications, our molecular phylogenies constructed with maximum likelihood and maximum parsimony place these general basal to a clade in which the Old World buntings and North American sparrows are sister groups. Contrary to the hypothesis that the radiation within Emberiza is recent following a westward expansion of emberizid stock into Eurasia from North Ame…

Operāciju māsas profesijas attīstības vēsture 20. gadsimta beigās Latvijā

2017

Oksana Sadigova izstrādāja bakalaura darbu par tēmu “Operāciju māsas profesijas attīstības vēsturi 20. gs beigās Latvijā” Latvijas Universitātes Medicīnas fakultātē, laika posmā no 2017. gada janvāra līdz 2017. gada maijam. Darba mērķis bija izpētīt un apkopot pieejamos datus par operāciju māsas attīstības vēsturi 20. gadsimta beigā Latvijā. Sakarā ar izvirzīto darba mērķi tika izvirzīti šādi uzdevumi: 1.Apkopot informāciju par operāciju māsas profesijas attīstību 20. gs. beigās, laikaposmā no 1970. līdz 2000. Gadam. 2.Izpētīt un izanalizēt zinātnisko literatūru par operāciju māsu profesijas attīstības vēsturi 20. gs. beigās Latvijā. Māsu teorijas analīze. 3.Izstrādāt pētnieciskā darba inst…

Multiple activation pathways of benzene leading to products with varying genotoxic characteristics.

1989

Abstract Benzene and 13 potential metabolites were investigated for genotoxicity in Salmonella typhimurium and V79 Chinese hamster cells. In the presence of NADPH-fortified hepatic postmitochondrial fraction (S9 mix), benzene reverted his- S. typhimurium strains. The effect was strongest in strain TA1535. Among the potential metabolites, only the trans-1,2-dihydrodiol, in the presence of S9 mix, and the diol epoxides, in the presence and absence of S9 mix, proved mutagenic in this strain. The anti-diol epoxide was more potent than the syn-diastereomer. Both enantiomers of the anti-diastereomer showed similar activities. S9 mix did not appreciably affect the mutagenicity of the anti-diol epo…

Tremadocian Stylophoran Echinoderms From The Taebaeksan Basin, Korea.

2006

15 pages; International audience; Abundant isolated elements of cornute and mitrate stylophorans were recovered from the upper Tremadocian Tumugol Formation in the Taebaeksan Basin, Korea. Cornute skeletal elements comprise a diverse assemblage of marginals and brachials of cothurnocystid affinities, suggesting the presence of no fewer than four different species. Mitrate remains include numerous isolated adorals, marginals, and aulacophoral plates with typical peltocystidan morphologies. Two adorals are identified as Anatifopsis sp., while all the others are attributable to A. cocaban. However, the two previously documented peltocystidans of Korea, A. cocaban and A. truncata, are sufficien…

Paraphyly of the Blue Tit (Parus caeruleus) suggested from cytochrome b sequences

2002

The phylogenetic relationships of the Blue Tit-Azure Tit assemblage (genus Parus; Aves: Passeriformes) were studied using mitochondrial DNA sequences of 24 specimens representing seven subspecies from Eurasia and North Africa. Previous work based on comparative morphological and acoustic data suggested a division of the Blue Tit (Parus caeruleus) into two species. Our analyses clearly indicate that the Blue Tit represents a paraphyletic assemblage, including a European/Middle Asian clade that is the sister group to the Azure Tit (Parus cyanus) and a North African clade. The North African clade (teneriffae subspecies group) is a sister group to the European Blue Tit/Azure Tit clade. We sugge…

A novel family of tRNA-derived SINEs in the colugo and two new retrotransposable markers separating dermopterans from primates.

2003

Abstract Short interspersed nuclear elements (SINEs) provide a near homoplasy free and copious source of molecular evolutionary markers with precisely defined character polarity. Used as molecular cladistic markers in presence/absence analyses, they represent a powerful complement to phylogenetic reconstructions that are based on sequence comparisons on the level of nucleotide substitutions. Recent sequence comparisons of large data sets incorporating a broad eutherian taxonomic sample have led to considerations of the different primate infraorders to constitute a paraphyletic group. Statistically significant support against the monophyly of primates has been obtained by clustering the flyi…

2014

The taxon Syndermata comprises the biologically interesting wheel animals (“Rotifera”: Bdelloidea + Monogononta + Seisonidea) and thorny-headed worms (Acanthocephala), and is central for testing superordinate phylogenetic hypotheses (Platyzoa, Gnathifera) in the metazoan tree of life. Recent analyses of syndermatan phylogeny suggested paraphyly of Eurotatoria (free-living bdelloids and monogononts) with respect to endoparasitic acanthocephalans. Data of epizoic seisonids, however, were absent, which may have affected the branching order within the syndermatan clade. Moreover, the position of Seisonidea within Syndermata should help in understanding the evolution of acanthocephalan endoparas…