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191.
The availability of genomic and proteomic data from across the tree of life has made it possible to infer features of the genome and proteome of the last universal common ancestor (LUCA). A number of studies have done so, all using a unique set of methods and bioinformatics databases. Here, we compare predictions across eight such studies and measure both their agreement with one another and with the consensus predictions among them. We find that some LUCA genome studies show a strong agreement with the consensus predictions of the others, but that no individual study shares a high or even moderate degree of similarity with any other individual study. From these observations, we conclude that the consensus among studies provides a more accurate depiction of the core proteome of the LUCA and its functional repertoire. The set of consensus LUCA protein family predictions between all of these studies portrays a LUCA genome that, at minimum, encoded functions related to protein synthesis, amino acid metabolism, nucleotide metabolism, and the use of common, nucleotide‐derived organic cofactors. 相似文献
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Veronique AJ Smits 《Cell cycle (Georgetown, Tex.)》2014,13(15):2330-2333
In recent years a growing recognition that molecularly-targeted therapies face formidable obstacles has revived interest in more generic tumor cell phenotypes that could be exploited for therapy. Two recent reports demonstrate that cancer cell survival is critically dependent on the activity of MTH1, a nucleotide pyrophosphatase that converts the oxidized nucleotides 8-oxo-dGTP and 2-OH-dATP to the corresponding monophosphates, thus preventing their incorporation into genomic DNA. Tumor cells frequently overexpress MTH1, probably because malignant transformation creates oxidative stress that renders the nucleotide pool highly vulnerable to oxidation. As a result, MTH1 inhibition in cancer cells results in accumulation and incorporation of 8-oxo-dGTP and 2-OH-dATP into DNA, leading to DNA damage and cell death. This toxic effect is highly cancer cell-specific, as MTH1 is generally dispensable for the survival of normal, untransformed cells. Importantly, MTH1 proves to be a “druggable” enzyme that can be inhibited both by an existing protein kinase inhibitor drug, crizotinib, and by novel compounds identified through screening. Inhibition of MTH1 leading to toxic accumulation of oxidized nucleotides specifically in tumor cells therefore represents an example of a “non-personalised” approach to cancer therapy. 相似文献
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Janet M. Bradford‐Grieve Geoffrey A. Boxshall Leocadio Blanco‐Bercial 《Zoological Journal of the Linnean Society》2014,171(3):507-533
A newly discovered plesiomorphic genus and species of calanoid copepod ( P inkertonius ambiguus gen. et sp. nov. ) taken with an epibenthic sledge from the flanks of the Chatham Rise, east of New Zealand, at a depth of about 900 m, could not be assigned to any known genus or family based on available diagnoses. A morphology‐based cladistic analysis of all genera previously placed in the Epacteriscidae, Pseudocyclopidae, Ridgewayiidae, Boholinidae, and the new taxon is presented. The Pseudocyclopidae and Epacteriscidae are confirmed as monophyletic families, and the family names Ridgewayiidae and Boholinidae become synonyms of Pseudocyclopidae. There are no grounds upon which more than a single basal superfamily, the Pseudocyclopoidea, can be recognized. The superfamily Pseudocyclopoidea, and families Pseudocyclopidae, Epacteriscidae, and the new genus are diagnosed. P inkertonius ambiguus gen. et sp. nov. is placed within the Pseudocyclopidae. Genetic data adds to the definition of the new taxon and confirms the basal position of the Pseudocyclopoidea in a revised Calanoida phylogeny. This phylogeny contributes to an improved resolution of the relationships among the Centropagoidea, Megacalanoidea, Bathypontioidea, Eucalanoidea, and Clausocalanoidea, as well as providing testable hypotheses for future work. © 2014 The Linnean Society of London 相似文献
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Systematic Parasitology - A new species of the copepod genus Pseudacanthocanthopsis Yamaguti & Yamasu, 1959 (family Chondracanthidae) is described based on material of both sexes collected... 相似文献
198.
Fa-Guo Wang Ai-Hua Wang Cheng-Ke Bai Dong-Mei Jin Li-Yun Nie AJ Harris Le Che Juan-Juan Wang Shi-Yu Li Lei Xu Hui Shen Yu-Feng Gu Hui Shang Lei Duan Xian-Chun Zhang Hong-Feng Chen Yue-Hong Yan 《Plant Diversity》2022,44(2):141
Ferns and lycophytes have remarkably large genomes. However, little is known about how their genome size evolved in fern lineages. To explore the origins and evolution of chromosome numbers and genome size in ferns, we used flow cytometry to measure the genomes of 240 species (255 samples) of extant ferns and lycophytes comprising 27 families and 72 genera, of which 228 species (242 samples) represent new reports. We analyzed correlations among genome size, spore size, chromosomal features, phylogeny, and habitat type preference within a phylogenetic framework. We also applied ANOVA and multinomial logistic regression analysis to preference of habitat type and genome size. Using the phylogeny, we conducted ancestral character reconstruction for habitat types and tested whether genome size changes simultaneously with shifts in habitat preference. We found that 2C values had weak phylogenetic signal, whereas the base number of chromosomes (x) had a strong phylogenetic signal. Furthermore, our analyses revealed a positive correlation between genome size and chromosome traits, indicating that the base number of chromosomes (x), chromosome size, and polyploidization may be primary contributors to genome expansion in ferns and lycophytes. Genome sizes in different habitat types varied significantly and were significantly correlated with habitat types; specifically, multinomial logistic regression indicated that species with larger 2C values were more likely to be epiphytes. Terrestrial habitat is inferred to be ancestral for both extant ferns and lycophytes, whereas transitions to other habitat types occurred as the major clades emerged. Shifts in habitat types appear be followed by periods of genomic stability. Based on these results, we inferred that habitat type changes and multiple whole-genome duplications have contributed to the formation of large genomes of ferns and their allies during their evolutionary history. 相似文献
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Two new Oncaea species, O.umerus and O.hawii, are describedfrom females taken in the central Red Sea. They are closelyrelated to each other and to a group of Oncaea similis-likespecies, whose morphological characteristics are reviewed forcomparison. 相似文献
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