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971.
Marie Gerlitz Michael Knopp Nils Kapust Joana C. Xavier William F. Martin 《Biology direct》2018,13(1):21
Background
The origin of eukaryotic cells was an important transition in evolution. The factors underlying the origin and evolutionary success of the eukaryote lineage are still discussed. One camp argues that mitochondria were essential for eukaryote origin because of the unique configuration of internalized bioenergetic membranes that they conferred to the common ancestor of all known eukaryotic lineages. A recent paper by Lynch and Marinov concluded that mitochondria were energetically irrelevant to eukaryote origin, a conclusion based on analyses of previously published numbers of various molecules and ribosomes per cell and cell volumes as a presumed proxy for the role of mitochondria in evolution. Their numbers were purportedly extracted from the literature.Results
We have examined the numbers upon which the recent study was based. We report that for a sample of 80 numbers that were purportedly extracted from the literature and that underlie key inferences of the recent study, more than 50% of the values do not exist in the cited papers to which the numbers are attributed. The published result cannot be independently reproduced. Other numbers that the recent study reports differ inexplicably from those in the literature to which they are ascribed. We list the discrepancies between the recently published numbers and the purported literature sources of those numbers in a head to head manner so that the discrepancies are readily evident, although the source of error underlying the discrepancies remains obscure.Conclusion
The data purportedly supporting the view that mitochondria had no impact upon eukaryotic evolution data exhibits notable irregularities. The paper in question evokes the impression that the published numbers are of up to seven significant digit accuracy, when in fact more than half the numbers are nowhere to be found in the literature to which they are attributed. Though the reasons for the discrepancies are unknown, it is important to air these issues, lest the prominent paper in question become a point source of a snowballing error through the literature or become interpreted as a form of evidence that mitochondria were irrelevant to eukaryote evolution.Reviewers
This article was reviewed by Eric Bapteste, Jianzhi Zhang and Martin Lercher.972.
Aline Paiva Morais Medeiros Josias Henrique de Amorim Xavier Marianna Barbosa da Silva Luana Aires-Souza Ierecê Maria de Lucena Rosa 《Marine Biology Research》2018,14(5):524-536
The Mamanguape River Estuary was studied along a continuum ranging from shallow sandstone reefs adjacent to the river mouth up to the limit of influence of seawater, the upper portions of the estuary. Fish samples were gathered using three types of nets along 17 sample sites, grouped in four regions according to salinity range (reefs and low, middle and upper estuaries), to seasonality (dry and rainy seasons) and to habitat usage (marine visitor, marine estuarine-opportunist, marine estuarine-dependent, estuarine resident and estuarine &; marine). Differences were found in the fish assemblages along the estuarine-reef gradient, with most species (n?=?30) being considered marine, estuarine-opportunists or estuarine-dependent, according to its abundance and distribution. A low number of species (n?=?11) were considered estuarine residents. Some species exhibited significant differences in spatial distribution pattern, in which juveniles and adults predominated in different portions of the estuary, suggesting an ontogenetic migration both in relation to the adjacent reef area and across estuarine regions. Several species were newly recorded in the Mamanguape Estuary: Anchoa spinifer, Halichoeres poeyi, Hyporhamphus roberti, Scomberomorus cavalla, Sphyraena barracuda and Ocgocephalus vesperilio. 相似文献
973.
974.
Terre Rosse deposits (upper Miocene; Gargano, Italy) have provided fossil remains of an insular fauna among which the genus Mikrotia (Rodentia) stands out. Several paleobiological studies have already been conducted on this genus, but its body mass has not yet been calculated accurately. The aim of the present work is to reconstruct Mikrotia magna's weight, a paramount aspect of organismal biology, especially on islands where mammals modify their size, becoming giants or dwarfs (‘island rule’). Our analysis using postcranial elements (femora and humeri) predicts weights ranging from 1300 g to 1900 g (old and young populations, respectively). The presence of a large number of micromammals on the Gargano paleo-island suggests a high interspecific competition for species of the same ecological guild (Prolagus or cricetids were direct competitors of Mikrotia), which may lead to only moderate gigantism, or even body mass reductions in small mammals, following Palkovacs's model. This contrasts with the huge weight of M. magna inferred in this study. In this regard, stratigraphic and taxonomic studies suggest that M. magna was an immigrant from a neighboring island, indicating that this species originated and achieved its enormous size under other selective pressures. A native island with a lower number of competitors, and therefore with less resource limitation than Terre Rosse, might be the principal explanation for such a degree of gigantism. 相似文献
975.
Laura De-Ugarte Jenny Serra-Vinardell Lara Nonell Susana Balcells Magdalena Arnal Xavier Nogues Leonardo Mellibovsky Daniel Grinberg Adolfo Diez-Perez Natalia Garcia-Giralt 《Human cell》2018,31(1):33-41
Bone tissue is composed of several cell types, which express their own microRNAs (miRNAs) that will play a role in cell function. The set of total miRNAs expressed in all cell types configures the specific signature of the bone tissue in one physiological condition. The aim of this study was to explore the miRNA expression profile of bone tissue from postmenopausal women. Tissue was obtained from trabecular bone and was analyzed in fresh conditions (n = 6). Primary osteoblasts were also obtained from trabecular bone (n = 4) and human osteoclasts were obtained from monocyte precursors after in vitro differentiation (n = 5). MicroRNA expression profiling was obtained for each sample by microarray and a global miRNA analysis was performed combining the data acquired in all the microarray experiments. From the 641 miRNAs detected in bone tissue samples, 346 (54%) were present in osteoblasts and/or osteoclasts. The other 46% were not identified in any of the bone cells analyzed. Intersection of osteoblast and osteoclast arrays identified 101 miRNAs shared by both cell types, which accounts for 30–40% of miRNAs detected in these cells. In osteoblasts, 266 miRNAs were detected, of which 243 (91%) were also present in the total bone array, representing 38% of all bone miRNAs. In osteoclasts, 340 miRNAs were detected, of which 196 (58%) were also present in the bone tissue array, representing 31% of all miRNAs detected in total bone. These analyses provide an overview of miRNAs expressed in bone tissue, broadening our knowledge in the microRNA field. 相似文献
976.
Antimitotic and hormone effects on green double haploid plant production through anther culture of Mediterranean japonica rice 总被引:1,自引:0,他引:1
Isidre Hooghvorst Eduardo Ramos-Fuentes Camilo López-Cristofannini Mirari Ortega Raimon Vidal Xavier Serrat Salvador Nogués 《Plant Cell, Tissue and Organ Culture》2018,134(2):205-215
Rice double haploid (DH) plants are produced mainly through anther culture. In order to improve the anther culture protocol, microspores of two japonica rice genotypes (NRVC980385 and H28) were subjected to three growth regulator combinations and four colchicine treatments on induction medium. In addition, a post anther culture procedure using colchicine or oryzalin was tested to induce double haploid plantlets from haploid plantlets. A cold pre-treatment of microspores for 9 days at 10 °C increased callus induction 50-fold in the NRCV980385 genotype. For both genotypes, 2 mg L?1 2,4-D and 1 mg L?1 kinetin on colchicine-free induction medium gave the best culture responses. The culturability of both genotypes changed on colchicine-supplemented induction media. A high genotype dependency was recorded for callus induction, callus regenerating green plantlets and regeneration of green double haploid plantlets. Colchicine at 300 mg L?1 for 48 h enhanced callus induction 100-fold in H28. Colchicine-supplemented media clearly improved green double haploid plantlet regeneration. We showed that the post-anther culture treatment of haploid plantlets at 500 mg L?1 of colchicine permitted fertile double haploid plantlets to be generated. Finally, an enhanced medium-throughput flow cytometry protocol for rice was tested to analyse all the plantlets from anther and post anther culture. 相似文献
977.
Julia Perdrial Paul D. Brooks Tyson Swetnam Kathleen A. Lohse Craig Rasmussen Marcy Litvak Adrian A. Harpold Xavier Zapata-Rios Patrick Broxton Bhaskar Mitra Tom Meixner Kate Condon David Huckle Clare Stielstra Angélica Vázquez-Ortega Rebecca Lybrand Molly Holleran Caitlin Orem Jon Pelletier Jon Chorover 《Biogeochemistry》2018,138(3):225-243
Climate-driven changes in carbon (C) cycling of forested ecosystems have the potential to alter long-term C sequestration and the global C balance. Prior studies have shown that C uptake and partitioning in response to hydrologic variation are system specific, suggesting that a comprehensive assessment is required for distinct ecosystems. Many sub-humid montane forest ecosystems in the US are projected to experience increased water limitation over the next decades and existing water-limited forests can be used as a model for how changes in the hydrologic cycle will impact such ecosystems more broadly. Toward that goal we monitored precipitation, net ecosystem exchange and lateral soil and stream C fluxes in three semi-arid to sub-humid montane forest catchments for several years (WY 2009–2013) to investigate how the amount and timing of water delivery affect C stores and fluxes. The key control on aqueous and gaseous C fluxes was the distribution of water between winter and summer precipitation, affecting ecosystem C uptake versus heterotrophic respiration. We furthermore assessed C stores in soil and above- and below-ground biomass to assess how spatial patterns in water availability influence C stores. Topographically-driven patterns in catchment wetness correlated with modeled soil C stores, reflecting both long-term trends in local C uptake as well as lateral redistribution of C leached from upslope organic soil horizons to convergent landscape positions. The results suggest that changes in the seasonality of precipitation from winter snow to summer rain will influence both the amount and the spatial distribution of soil C stores. 相似文献
978.
Eva De Mol Elzbieta Szulc Claudio Di Sanza Paula Martínez-Cristóbal Carlos W. Bertoncini R. Bryn Fenwick Marta Frigolé-Vivas Marianela Masín Irene Hunter Víctor Buzón Isabelle Brun-Heath Jesús García Gianni De Fabritiis Eva Estébanez-Perpiñá Iain J. McEwan Ángel R. Nebreda Xavier Salvatella 《Structure (London, England : 1993)》2018,26(1):145-152.e3
979.
The Xerobranching Response Represses Lateral Root Formation When Roots Are Not in Contact with Water
Beata Orman-Ligeza Emily C. Morris Boris Parizot Tristan Lavigne Aurelie Babé Aleksander Ligeza Stephanie Klein Craig Sturrock Wei Xuan Ondřey Novák Karin Ljung Maria A. Fernandez Pedro L. Rodriguez Ian C. Dodd Ive De Smet Francois Chaumont Henri Batoko Claire Périlleux Xavier Draye 《Current biology : CB》2018,28(19):3165-3173.e5
980.