Search results for "Phylogenetics"
showing 10 items of 777 documents
Cardiac autonomic function reveals adaptation to military training
2011
Abstract The last 4 weeks of basic military training are very stressful. We tested the hypothesis that changes in cardiac autonomic function during this period are associated with changes in maximal oxygen uptake and/or serum hormonal concentrations in male conscripts (n=22). Cardiac vagal autonomic function was assessed by measuring the high-frequency (0.15–0.4 Hz) spectral power of R–R intervals. Maximal oxygen uptake ([Vdot]O2max) and basal serum testosterone concentration were measured at the beginning and end of the period. Individual changes in vagally mediated high-frequency power (range −15% to +25%) correlated (r=0.73, P=0.001) with changes in [Vdot]O2max (range −9% to +6%) and cha…
Taxonomic and phylogenetic relations of Allium chamaespathum Boiss., a remarkable species of Balkan Flora
2018
Allium chamaespathum Boiss., the only autumn-flowering species of Sect. Allium, was studied based on morphology, karyology, seed coat microsculpturing and DNA sequences from several populations.
Epidemiological dynamics of norovirus GII.4 variant New Orleans 2009.
2015
Norovirus (NoV) is one of the major causes of diarrhoeal disease with epidemic, outbreak and sporadic patterns in humans of all ages worldwide. NoVs of genotype GII.4 cause nearly 80–90 % of all NoV infections in humans. Periodically, some GII.4 strains become predominant, generating major pandemic variants. Retrospective analysis of the GII.4 NoV strains detected in Italy between 2007 and 2013 indicated that the pandemic variant New Orleans 2009 emerged in Italy in the late 2009, became predominant in 2010–2011 and continued to circulate in a sporadic fashion until April 2013. Upon phylogenetic analysis based on the small diagnostic regions A and C, the late New Orleans 2009 NoVs circulati…
Ventastega curonica and the origin of tetrapod morphology.
2008
The gap in our understanding of the evolutionary transition from fish to tetrapod is beginning to close thanks to the discovery of new intermediate forms such as Tiktaalik roseae. Here we narrow it further by presenting the skull, exceptionally preserved braincase, shoulder girdle and partial pelvis of Ventastega curonica from the Late Devonian of Latvia, a transitional intermediate form between the 'elpistostegids' Panderichthys and Tiktaalik and the Devonian tetrapods (limbed vertebrates) Acanthostega and Ichthyostega. Ventastega is the most primitive Devonian tetrapod represented by extensive remains, and casts light on a part of the phylogeny otherwise only represented by fragmentary ta…
Molecular characterization of hemoglobin from the honeybee Apis mellifera
2005
Due to the prevailing importance of the tracheal system for insect respiration, hemoglobins had been considered rare exceptions in this arthropod subphylum. Here we report the identification, cloning and expression analysis of a true hemoglobin gene in the honeybee Apis mellifera (Hymenoptera). The deduced amino acid sequence covers 171 residues (19.5 kDa) and harbors all globin-typical features, including the proximal and the distal histidines. The protein has no signal peptide for transmembrane transport and was predicted to localize in the cytoplasm. The honeybee hemoglobin gene shows an ancient structure, with introns in positions B12.2 and G7.0, while most other insect globins have div…
Isolation and characterization of two T-box genes from sponges, the phylogenetically oldest metazoan taxon
2003
It is now well established that all metazoan phyla derived from one common ancestor, the hypothetical Urmetazoa. Due to the basal position of Porifera (Demospongiae) in the phylogenetic tree of Metazoa, studies on the mechanisms controlling the development of these animals can provide clues on the understanding of the origin of multicellular animals and on how the first organization of the body plan evolved. In this report we describe the isolation and genomic characterization of two T-box genes from the siliceous sponge Suberites domuncula. The phylogenetic analysis classifies one into the subfamily of Brachyury, Sd-Bra, and the second into the Tbx2 subfamily, Sd-Tbx2. Analyses of the Sd-B…
Towards a Molecular Systematics of the Lake Baikal/Lake Tuva Sponges
2009
Lake Baikal is famous for its extensive biodiversity that is equaled only by few other lakes. Fascinatingly, about 80% of all the animals the lake hosts are endemic. Sponges (Porifera) that live in symbiosis with photosynthetic algae are the most abundant animal taxon found in the littoral zone of Lake Baikal and have been grouped to the family Lubomirskiidae. In recent years, several attempts to determine the phylogenetic relationship between Lubomirskiidae and cosmopolitan freshwater sponges have been undertaken. Yet the results obtained remain inconclusive. Here, we strive to determine the phylogeny of freshwater sponges with the focus on endemic Lake Baikal species, also taking into acc…
Spiralian phylogenomics supports the resurrection of Bryozoa comprising Ectoprocta and Entoprocta.
2007
Phylogenetic analyses based on 79 ribosomal proteins of 38 metazoans, partly derived from 6 new expressed sequence tag projects for Ectoprocta, Entoprocta, Sipuncula, Annelida, and Acanthocephala, indicate the monophyly of Bryozoa comprising Ectoprocta and Entoprocta, 2 taxa that have been separated for more than a century based on seemingly profound morphological differences. Our results also show that bryozoans are more closely related to Neotrochozoa, including molluscs and annelids, than to Syndermata, the latter comprising Rotifera and Acanthocephala. Furthermore, we find evidence for the position of Sipuncula within Annelida. These findings suggest that classical developmental and mor…
4-Aminopyridine (4AP) Enhances Acetylcholine Output from the Rat Cerebral Cortex in vivo
1982
Publisher Summary This chapter discusses a study to analyze the effect of 4-aminopyridine (4AP) administration on cortical acetylcholine (ACh) output. The study was done on adult male Wistar rats under urethane or pentobarbital anesthesia. A small Perspex cylinder filled with eserinized Ringer solution was applied on the exposed cerebral cortex. The solution in the collecting cylinder was removed every 10 min and its ACh content was determined by bioassay on the dorsal muscle of the leech. In urethane anaesthetized rats, the control ACh output was 0.98 ± 0.16 ng/min/cm2 and the administration of 4AP (3 mg/kg i.p.) was followed by a rapid increase in ACh output lasting at least 40 min. The i…
Evolution of growth form in epiphytic Dissochaeteae (Melastomataceae)
2001
Abstract We trace the evolution of root climbing and scrambling in Dissochaeteae and Sonerileae, two closely related groups that comprise the majority of Old World climbing Melastomataceae. The morphological and anatomical adaptations of the different climbers are interpreted in the context of a phylogeny based on chloroplast (cp) DNA sequences of the ndhF gene, generated for 31 representatives of Dissochaeteae and Sonerileae/Oxysporeae plus nine outgroups. For 20 of these taxa, the ndhF sequences were combined with cpDNA rpl16 intron sequences to obtain higher statistical support. Parsimony, minimum evolution, and maximum likelihood approaches yield congruent topologies that imply that scr…