Search results for "Clad"

Deep-Time Phylogenetic Clustering of Extinctions in an Evolutionarily Dynamic Clade (Early Jurassic Ammonites)

2012

7 pages; International audience; Conservation biologists and palaeontologists are increasingly investigating the phylogenetic distribution of extinctions and its evolutionary consequences. However, the dearth of palaeontological studies on that subject and the lack of methodological consensus hamper our understanding of that major evolutionary phenomenon. Here we address this issue by (i) reviewing the approaches used to quantify the phylogenetic selectivity of extinctions and extinction risks; (ii) investigating with a high-resolution dataset whether extinctions and survivals were phylogenetically clustered among early Pliensbachian (Early Jurassic) ammonites; (iii) exploring the phylogene…

Gastropod evidence against the Early Triassic Lilliput effect

2010

4 pages; International audience; Size reduction in the aftermath of the Permian-Triassic mass extinction event has repeatedly been described for various marine organisms, including gastropods (the Lilliput effect). A Smithian gastropod assemblage from Utah, USA, reveals numerous large-sized specimens of different genera as high as 70 mm, the largest ever reported from the Early Triassic. Other gastropods reported from Serbia and Italy are also as large as 35 mm. Size frequency distributions of the studied assemblages indicate that they were not unusually small when compared with later Mesozoic and modern faunas. The occurrence of large-sized gastropods less than 2 Ma after the Permian-Trias…

Evolution of Leaf Morphogenesis: Evidence from Developmental and Phylogenetic Data in Papaveraceae

1999

Variation of leaf morphology in Papaveraceae s.l. (including Fumariaceae and Pteridophyllum) has previously been shown to be related to developmental differences in the direction of segmentation and in blade‐petiole differentiation. Based on ontogenetic comparisons, we here distinguish polyternate, acropetal, basipetal‐pedate, basipetal‐pinnate, and divergent modes of dissection. In addition, undissected leaves occur in some taxa. Dissection modes can be grouped in two classes on the basis of blade‐petiole differentiation. Mapping of these morphogenetic traits on an independently obtained phylogenetic reconstruction reveals a high degree of homoplasy, indicating multiple evolutionary parall…

Comparative study of the toxicity of molinate for freshwater organisms.

2003

UV Radiation and Freshwater Zooplankton: Damage, Protection and Recovery

2011

While many laboratory and field studies show that zooplankton are negatively affected when exposed to high intensities of ultraviolet radiation (UVR), most studies also indicate that zooplankton are well adapted to cope with large variations in their UVR exposure in the pelagic zone of lakes. The response mechanisms of zooplankton are diverse and efficient and may explain the success and richness of freshwater zooplankton in optically variable waters. While no single behavioural or physiological protection mechanism seems to be superior, and while several unexplained and contradictory patterns exist in zooplankton UVR ecology, recent increases in our understanding are consistent with UVR pl…

Cork Taint of Wines: Role of the Filamentous Fungi Isolated from Cork in the Formation of 2,4,6-Trichloroanisole by O Methylation of 2,4,6-Trichlorop…

2002

ABSTRACT Cork taint is a musty or moldy off-odor in wine mainly caused by 2,4,6-trichloroanisole (2,4,6-TCA). We examined the role of 14 fungal strains isolated from cork samples in the production of 2,4,6-TCA by O methylation of 2,4,6-trichlorophenol (2,4,6-TCP). The fungal strains isolated belong to the genera Penicillium (four isolates); Trichoderma (two isolates); and Acremonium , Chrysonilia , Cladosporium , Fusarium , Mortierella , Mucor , Paecilomyces , and Verticillium (one isolate each). Eleven of these strains could produce 2,4,6-TCA when they were grown directly on cork in the presence of 2,4,6-TCP. The highest levels of bioconversion were carried out by the Trichoderma and Fusar…

Expression of retinoic acid nuclear receptors in the mouse embryonal carcinoma cell line PCC7-Mz1

1992

Mouse embryonal carcinoma cell line PCC7-Mz1 can serve as a model of mammalian neural development [1989, J. Cell. Biol. 109, 2481-2493]. Upon exposure to all-trans retinoic acid (RA), Mz1 cells differentiate into a stable pattern of neurons, astroglia and fibroblasts whereas variants of the parental cell line either are restricted in their patterns of derivatives or do not respond at all to RA. Using gene probes specific for the alpha 1, alpha 2 and beta 2 isoforms of the retinoic acid nuclear receptor, we have studied by Northern blot analysis the expression of these transcription factors in uninduced and induced cells of clone Mz1 and in variants with different developmental potential. al…

Seasonal characterization of nutritional and antioxidant properties of Opuntia ficus-indica [(L.) Mill.] mucilage

2021

Abstract Opuntia ficus-indica fruit and cladodes are a source of mucilage, a carbohydrate complex, as well as of phytochemicals and other nutrients, useful in the food industry. Despite the environmental-based composition variability has been studied, there is no information on its seasonal variability, which is particularly important for its industrial use. In this study, some technological, nutritional, and bioactive properties of O. ficus-indica cladodes mucilage were analyzed during the seasonal growth period. Total proteins did not change during the whole period and the lipid content significantly decreased from winter to the onset of summer. The fatty acid profile showed high levels o…

First steps to restructuring the problematic genus Lasiotocus Looss, 1907 (Digenea: Monorchiidae) with the proposal of four new genera

2020

Lasiotocus Looss, 1907 is the largest genus within the Monorchiidae Odhner, 1911, with 52 species currently considered valid. Species belonging to this genus exhibit wide morphological variation and it is likely that many of them belong in other genera; however, testing the validity of the group has been hampered by a lack of molecular sequence data, especially for the type-species. Here, we report the first DNA sequences for Lasiotocus mulli (Stossich, 1883) Odhner, 1911, the type-species of the genus, and only the sixth Lasiotocus species to be sequenced. Sequences were generated for three ribosomal DNA markers, the ITS2, 18S and 28S regions, and for one mitochondrial DNA marker, the cox1…

Phylogeography of the Eurasian Willow Tit (Parus montanus) based on DNA sequences of the mitochondrial cytochrome b gene.

2002

The phylogeographic relationships of the trans-Palearctic Willow Tit assemblage were studied by obtaining sequence data from the mitochondrial cytochrome b gene from 34 specimens representing nine subspecies from across the species range. Four distinct genetic groups were identified: Parus montanus weigoldicus, P. m. affinis, P. m. songarus, and a clade containing six Eurasian subspecies (ssp. baicalensis, borealis, montanus, restrictus, rhenanus, and sachalinensis). P. m. weigoldicus, P. m. affinis, and P. m. songarus were reciprocally monophyletic and separated from each other and other subspecies by uncorrected genetic distances between 1.9 and 5.8%. The remaining six subspecies were clo…