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761.
In this note we reassess the position of putative pedal phalanges of some South American noasaurid theropods (Abelisauroidea).
Noasaurids were considered as to be distinctive abelisauroids with a peculiar “sickle claw” on the second toe of the foot,
convergently developed with that of deinonychosaurians. Among noasaurids, the Argentinean species Noasaurus leali (latest Cretaceous) and Ligabueino andesi (Early Cretaceous) are known from incomplete specimens, including dissarticulated non-ungueal phalanges, and, in N. leali, a claw. A detailed overview of these elements indicates that the supposed raptorial claw of the second pedal digit of N. leali actually belongs to the first or second finger of the manus, and the putative pedal non-ungual phalanges of both genera also
pertain to the manus. Thus, the new interpretations of noasaurid pedal morphology blur the distinctions between Noasauridae
and Velocisauridae proposed by previous authors. Finally, we suggest, on the basis of phalangeal and metacarpal morphology,
that abelisaurids probably lost their manual claws by means of the loss of function of the HOXA11 and HOXD11 genes. Thus Noasauridae
differs from Abelisauridae in retaining plesiomorphic long forelimbs with well developed claws, as occurs plesiomorphically
in most basal theropods (e.g., Coelophysis). 相似文献
762.
Massimo Reverberi Federico Punelli Marzia Scarpari Emanuela Camera Slaven Zjalic Alessandra Ricelli Corrado Fanelli Anna Adele Fabbri 《Applied microbiology and biotechnology》2010,85(6):1935-1946
In Aspergillus nidulans, Aspergillus flavus, and Aspergillus parasiticus, lipoperoxidative signalling is crucial for the regulation of mycotoxin biosynthesis, conidiogenesis, and sclerotia formation.
Resveratrol, which is a lipoxygenase (LOX) and cyclooxygenase inhibitor, downmodulates the biosynthesis of ochratoxin A (OTA)
in Aspergillus ochraceus. In the genome of A. ochraceus, a lox-like sequence (AoloxA; National Center for Biotechnology Information (NCBI) accession number: DQ087531) for a lipoxygenase-like enzyme has been
found, which presents high homology (100 identities, 100 positives %, score 555) with a lox gene of Aspergillus fumigatus (NCBI accession number: XM741370). To study how inhibition of oxylipins formation may affect the A. ochraceus metabolism, we have used a ΔAoloxA strain. This mutant displays a different colony morphology, a delayed conidia formation, and a high sclerotia production.
When compared to the wild type, the ΔAoloxA strain showed a lower basal activity of LOX and diminished levels of 13-hydroperoxylinoleic acid (HPODE) and other oxylipins
derived from linoleic acid. The limited oxylipins formation corresponded to a remarkable inhibition of OTA biosynthesis in
the ΔAoloxA strain. Also, wheat seeds (Triticum durum cv Ciccio) inoculated with the ΔAoloxA mutant did not accumulate 9-HPODE, which is a crucial element in the host defence system. Similarly, the expression of the
pathogenesis-related protein 1 (PR1) gene in wheat seeds was not enhanced. The results obtained contribute to the current knowledge on the role of lipid peroxidation
governed by the AoloxA gene in the morphogenesis, OTA biosynthesis, and in host–pathogen interaction between wheat seeds and A. ochraceus. 相似文献
763.
Bartolomeo Schirone Raquel Caetano Ferreira Federico Vessella Avra Schirone Roberta Piredda Marco Cosimo Simeone 《Biodiversity and Conservation》2010,19(6):1547-1565
Taxus baccata L., a Tertiary relict formerly widespread in the Azores Archipelago, was recently classified as “probably extinct”. This
paper documents the persistence of the species in the Azores and provides its first characterization by means of morphometric
and genetic analyses. Only five individuals were found, growing on Pico Island. Although the population size is critically
small it retains some highly significant characteristics for the assessment of the genetic diversity of the species and its
phylogeography. The leaves of the Azorean provenance were smaller than those of all other Taxus baccata described in literature; moreover, they have a higher stomata density and more numerous stomata rows. These features are
all “primitive”, according to suggested morphological evolutionary trends. We assume that sequence analysis of the chloroplast
trnS–trnQ intergenic spacer demonstrates that the Azorean population represents a different evolutionary line within Taxus. This suggests a more direct derivation from ancestors than provenances from Mediterranean and European regions. These individuals
may be the last survivors of an ancient lineage, preserved in the Azores as part of the Macaronesian flora. Immediate conservation
action focusing on site protection and ex situ reproduction strategies is recommended to save this lineage from imminent extinction. 相似文献
764.
765.
766.
Dolores Solís María Jesus Maté Michaela Lohr João P. Ribeiro Lara López-Merino Sabine André Eliza Buzamet F. Javier Cañada Herbert Kaltner Martin Lensch Federico M. Ruiz Gunter Haroske Uwe Wollina Matthias Kloor Jürgen Kopitz José L. Sáiz Margarita Menéndez Jesús Jiménez-Barbero Antonio Romero Hans-Joachim Gabius 《The international journal of biochemistry & cell biology》2010,42(6):1019-1029
Human tandem-repeat-type galectin-9 is a potent adhesion/growth-regulatory effector via lectin capacity of its N- and C-terminal domains. This bioactivity prompted further crystallographic study of the N-domain, combined with analysis in solution. Binding of lactose markedly increased the N-domain's resistance to thermal denaturation. Crystallography revealed its intimate contact profile, besides detecting an extension of the β-sandwich fold by an antiparallel β-strand F0 aligned to the C-terminal F1 strand. Ligand accommodation in its low-energy conformation leads to a movement of Arg87's side chain. As consequence, the ligand's glucose moiety and Arg87 become hydrogen bonded. The resulting predictions for spatial parameters in solution were verified by determining (a) the pattern of magnetization transfer from the protein to protons of lactose and Forssman disaccharide by NMR spectroscopy and (b) the ellipticity changes at wavelengths characteristic for Trp/Tyr residues in near-UV CD spectroscopy. Whereas solid-phase assays confirmed a previously noted tendency for homo- and heterotypic aggregation, gel filtration and ultracentrifugation disclosed monomeric status in solution, in line with crystallographic data. Using cell mutants with defects in glycosylation, this lectin domain was shown to preferentially bind N-glycans without α2,3-sialylation. Since proximal promoter sequences were delineated to diverge markedly among galectin genes and resulting differences in expression profiles were exemplarily documented immunohistochemically, the intrafamily diversification appears to have assigned this protein to a characteristic expression and activity profile among galectins. Our data thus take the crystallographic information to the level of the lectin in solution and in tissues by a strategic combination of spectroscopic and cell/histochemical assays. 相似文献
767.
768.
Lily Ting Timothy J. Williams Mark J. Cowley Federico M. Lauro Michael Guilhaus Mark J. Raftery Ricardo Cavicchioli 《Environmental microbiology》2010,12(10):2658-2676
The cold marine environment constitutes a large proportion of the Earth's biosphere. Sphingopyxis alaskensis was isolated as a numerically abundant bacterium from several cold marine locations, and has been extensively studied as a model marine bacterium. Recently, a metabolic labelling platform was developed to comprehensively identify and quantify proteins from S. alaskensis. The approach incorporated data normalization and statistical validation for the purpose of generating highly confident quantitative proteomics data. Using this approach, we determined quantitative differences between cells grown at 10°C (low temperature) and 30°C (high temperature). Cold adaptation was linked to specific aspects of gene expression: a dedicated protein‐folding system using GroESL, DnaK, DnaJ, GrpE, SecB, ClpB and PPIase; polyhydroxyalkanoate‐associated storage materials; a link between enzymes in fatty acid metabolism and energy generation; de novo synthesis of polyunsaturated fatty acids in the membrane and cell wall; inorganic phosphate ion transport by a phosphate import PstB homologue; TonB‐dependent receptor and bacterioferritin in iron homeostasis; histidine, tryptophan and proline amino acid metabolism; and a large number of proteins without annotated functions. This study provides a new level of understanding on how important marine bacteria can adapt to compete effectively in cold marine environments. This study is also a benchmark for comparative proteomic analyses with other important marine bacteria and other cold‐adapted organisms. 相似文献
769.
Background
Taxon sampling is a major concern in phylogenetic studies. Incomplete, biased, or improper taxon sampling can lead to misleading results in reconstructing evolutionary relationships. Several theoretical methods are available to optimize taxon choice in phylogenetic analyses. However, most involve some knowledge about the genetic relationships of the group of interest (i.e., the ingroup), or even a well-established phylogeny itself; these data are not always available in general phylogenetic applications. 相似文献770.