A genomic approach to examine the complex evolution of laurasiatherian mammals
Björn M. Hallström
- Recent phylogenomic studies have failed to conclusively resolve certain branches of the placental mammalian tree, despite the evolutionary analysis of genomic data from 32 species. Previous analyses of single genes and retroposon insertion data yielded support for different phylogenetic scenarios for the most basal divergences. The results indicated that some mammalian divergences were best interpreted not as a single bifurcating tree, but as an evolutionary network. In these studies the relationships among some orders of the super-clade Laurasiatheria were poorly supported, albeit not studied in detail. Therefore, 4775 protein-coding genes (6,196,263 nucleotides) were collected and aligned in order to analyze the evolution of this clade. Additionally, over 200,000 introns were screened in silico, resulting in 32 phylogenetically informative long interspersed nuclear elements (LINE) insertion events.
The present study shows that the genome evolution of Laurasiatheria may best be understood as an evolutionary network. Thus, contrary to the common expectation to resolve major evolutionary events as a bifurcating tree, genome analyses unveil complex speciation processes even in deep mammalian divergences. We exemplify this on a subset of 1159 suitable genes that have individual histories, most likely due to incomplete lineage sorting or introgression, processes that can make the genealogy of mammalian genomes complex.
These unexpected results have major implications for the understanding of evolution in general, because the evolution of even some higher level taxa such as mammalian orders may sometimes not be interpreted as a simple bifurcating pattern.
Systematic revision of the American taxa belonging to the genera Alloblackburneus Bordat, 2009, and Blackburneus Schmidt, 1913, with description of seven new species (Coleoptera: Scarabaeidae: Aphodiinae)
Robert D. Gordon
- The American species belonging to the genera Alloblackburneus Bordat and Blackburneus Schmidt
(Coleoptera: Scarabaeidae: Aphodiinae) are redescribed and figured. Seven new species are described:
Alloblackburneus guadalajarae, A. ibanezbernali; Blackburneus amazonicus, B. sanfilippoi, B. surinamensis, B.
teposcolulaensis, B. thomasi. The neotype of Scarabaeus rubeolus Palisot de Beauvois, 1809 is designated. The
lectotype of Blackburneus argentinensis (Schmidt, 1909) and of Blackburneus laxepunctatus (Schmidt, 1910) are
designated. The following new combinations are proposed: Alloblackburneus aegrotus (Horn, 1870);
Alloblackburneus cavidomus (Brown, 1927); Alloblackburneus cynomysi (Brown, 1927); Alloblackburneus fordi (Gordon,
1974); Alloblackburneus geomysi (Cartwright, 1939); Alloblackburneus lentus (Horn, 1870); Alloblackburneus
rubeolus (Palisot de Beauvois, 1805); Alloblackburneus saylori (Hinton, 1934); Alloblackburneus tenuistriatus (Horn,
1887); Alloblackburneus troglodytes (Hubbard, 1894).
Goethe-Spektrum : das Mitarbeitermagazin der Goethe-Universität Frankfurt ; 4/11
The first vouchered milliped records for Prince Edward Island and additional new records from the Maritime Provinces of Canada (Arthropoda: Diplopoda)
Rowland M. Shelley
Mary E. Smith
- Four milliped species, substantiated by preserved voucher samples, are reported from Prince Edward
Island, Canada. All are introduced European species that now occur widely in both Canada and the United States,
and the panglobal Asian paradoxosomatid, Oxidus gracilis (C. L. Koch, 1847), is listed as probable. Choneiulus
palmatus (Némec, 1895) (Julida: Blaniulidae) is newly recorded from New Brunswick, and four representatives
of the Julidae are cited from Nova Scotia. Discovery of Cylindroiulus punctatus (Leach, 1815) (Julidae) in this
province constitutes the second record from both Canada and North America, the other being in Newfoundland.
Vespidae (Insecta: Hymenoptera) of Puerto Rico, West Indies
James M. Carpenter
Julio A. Genaro
- The vespid fauna of Greater Puerto Rico is reviewed (Hymenoptera: Vespidae). Three new species are
described, Ancistrocerus isla Carpenter, Euodynerus jeitita Carpenter and Genaro, and Omicron aridum Carpenter
and Genaro. Polistes crinitus americanus (Fabricius, 1775) and P. crinitus multicolor (Olivier, 1792) are both
reduced to synonyms of nominotypical P. crinitus (Felton, 1765), revised status; Zeta abdominale hispaniolae
(Bequaert and Salt, 1931) and Zeta abdominale ornatum (de Saussure, 1855) are both reduced to synonyms of
nominotypical Zeta abdominale (Drury, 1770), revised status; and Zethus rufinodus monensis Bohart and Stange,
1965, and Zethus rufinodus virginicus Bohart and Stange, 1965, are both reduced to synonyms of nominotypical
Zethus rufinodus (Latreille, 1806), revised status. Parancistrocerus obliquus (Cresson, 1865) is newly recorded
from Puerto Rico. The presence of Pachodynerus guadulpensis (de Saussure, 1853) in Puerto Rico is confirmed. An
analysis of the composition of the Puerto Rican vespid fauna is presented.
Inner ear morphology in the Atlantic molly Poecilia mexicana - first detailed microanatomical study of the inner ear of a cyprinodontiform species
- Background: Fishes show an amazing diversity in hearing abilities, inner ear structures, and otolith morphology. Inner ear morphology, however, has not yet been investigated in detail in any member of the diverse order Cyprinodontiformes. We, therefore, studied the inner ear of the cyprinodontiform freshwater fish Poecilia mexicana by analyzing the position of otoliths in situ, investigating the 3D structure of sensory epithelia, and examining the orientation patterns of ciliary bundles of the sensory hair cells, while combining μ-CT analyses, scanning electron microscopy, and immunocytochemical methods. P. mexicana occurs in different ecotypes, enabling us to study the intra-specific variability (on a qualitative basis) of fish from regular surface streams, and the Cueva del Azufre, a sulfidic cave in southern Mexico.
Results: The inner ear of Poecilia mexicana displays a combination of several remarkable features. The utricle is connected rostrally instead of dorso-rostrally to the saccule, and the macula sacculi, therefore, is very close to the utricle. Moreover, the macula sacculi possesses dorsal and ventral bulges. The two studied ecotypes of P. mexicana showed variation mainly in the shape and curvature of the macula lagenae, in the curvature of the macula sacculi, and in the thickness of the otolithic membrane.
Conclusions: Our study for the first time provides detailed insights into the auditory periphery of a cyprinodontiform inner ear and thus serves a basis—especially with regard to the application of 3D techniques—for further research on structure-function relationships of inner ears within the species-rich order Cyprinodontiformes. We suggest that other poeciliid taxa, or even other non-poeciliid cyprinodontiforms, may display similar inner ear morphologies as described here.
Ships, ports and particulate air pollution - an analysis of recent studies
Jan David Alexander Groneberg
- The duration of use is usually significantly longer for marine vessels than for roadside vehicles. Therefore, these vessels are often powered by relatively old engines which may propagate air pollution. Also, the quality of fuel used for marine vessels is usually not comparable to the quality of fuels used in the automotive sector and therefore, port areas may exhibit a high degree of air pollution. In contrast to the multitude of studies that addressed outdoor air pollution due to road traffic, only little is known about ship-related air pollution. Therefore the present article aims to summarize recent studies that address air pollution, i.e. particulate matter exposure, due to marine vessels. It can be stated that the data in this area of research is still largely limited. Especially, knowledge on the different air pollutions in different sea areas is needed.
Drowning - a scientometric analysis and data acquisition of a constant global problem employing density equalizing mapping and scientometric benchmarking procedures
Jan David Alexander Groneberg
Drowning is a constant global problem which claims proximately half a million victims worldwide each year, whereas the number of near-drowning victims is considerably higher. Public health strategies to reduce the burden of death are still limited. While research activities in the subject drowning grow constantly, yet there is no scientometric evaluation of the existing literature at the present time.
The current study uses classical bibliometric tools and visualizing techniques such as density equalizing mapping to analyse and evaluate the scientific research in the field of drowning. The interpretation of the achieved results is also implemented in the context of the data collection of the WHO.
All studies related to drowning and listed in the ISI-Web of Science database since 1900 were identified using the search term "drowning". Implementing bibliometric methods, a constant increase in quantitative markers such as number of publications per state, publication language or collaborations as well as qualitative markers such as citations were observed for research in the field of drowning. The combination with density equalizing mapping exposed different global patterns for research productivity and the total number of drowning deaths and drowning rates respectively. Chart techniques were used to illustrate bi- and multilateral research cooperation.
The present study provides the first scientometric approach that visualizes research activity on the subject of drowning. It can be assumed that the scientific approach to this topic will achieve even greater dimensions because of its continuing actuality.
Shared and unique patterns of embryo development in extremophile poeciliids
R. Brian Langerhans
- Background: Closely related lineages of livebearing fishes have independently adapted to two extreme environmental factors: toxic hydrogen sulphide (H2S) and perpetual darkness. Previous work has demonstrated in adult specimens that fish from these extreme habitats convergently evolved drastically increased head and offspring size, while cave fish are further characterized by reduced pigmentation and eye size. Here, we traced the development of these (and other) divergent traits in embryos of Poecilia mexicana from benign surface habitats (“surface mollies”) and a sulphidic cave (“cave mollies”), as well as in embryos of the sister taxon, Poecilia sulphuraria from a sulphidic surface spring (“sulphur mollies”). We asked at which points during development changes in the timing of the involved processes (i.e., heterochrony) would be detectible.
Methods and Results: Data were extracted from digital photographs taken of representative embryos for each stage of development and each type of molly. Embryo mass decreased in convergent fashion, but we found patterns of embryonic fat content and ovum/embryo diameter to be divergent among all three types of mollies. The intensity of yellow colouration of the yolk (a proxy for carotenoid content) was significantly lower in cave mollies throughout development. Moreover, while relative head size decreased through development in surface mollies, it increased in both types of extremophile mollies, and eye growth was arrested in mid-stage embryos of cave mollies but not in surface or sulphur mollies.
Conclusion: Our results clearly demonstrate that even among sister taxa convergence in phenotypic traits is not always achieved by the same processes during embryo development. Furthermore, teleost development is crucially dependent on sufficient carotenoid stores in the yolk, and so we discuss how the apparent ability of cave mollies to overcome this carotenoid-dependency may represent another potential mechanism explaining the lack of gene flow between surface and cave mollies.
N-terminal arginines modulate plasma-membrane localization of Kv7.1/KCNE1 channel complexes
Stefan H. Hohnloser
- Background and Objective: The slow delayed rectifier current (IKs) is important for cardiac action potential termination. The underlying channel is composed of Kv7.1 α-subunits and KCNE1 β-subunits. While most evidence suggests a role of KCNE1 transmembrane domain and C-terminus for the interaction, the N-terminal KCNE1 polymorphism 38G is associated with reduced IKs and atrial fibrillation (a human arrhythmia). Structure-function relationship of the KCNE1 N-terminus for IKs modulation is poorly understood and was subject of this study.
Methods: We studied N-terminal KCNE1 constructs disrupting structurally important positively charged amino-acids (arginines) at positions 32, 33, 36 as well as KCNE1 constructs that modify position 38 including an N-terminal truncation mutation. Experimental procedures included molecular cloning, patch-clamp recording, protein biochemistry, real-time-PCR and confocal microscopy.
Results: All KCNE1 constructs physically interacted with Kv7.1. IKs resulting from co-expression of Kv7.1 with non-atrial fibrillation ‘38S’ was greater than with any other construct. Ionic currents resulting from co-transfection of a KCNE1 mutant with arginine substitutions (‘38G-3xA’) were comparable to currents evoked from cells transfected with an N-terminally truncated KCNE1-construct (‘Δ1-38’). Western-blots from plasma-membrane preparations and confocal images consistently showed a greater amount of Kv7.1 protein at the plasma-membrane in cells co-transfected with the non-atrial fibrillation KCNE1-38S than with any other construct.
Conclusions: The results of our study indicate that N-terminal arginines in positions 32, 33, 36 of KCNE1 are important for reconstitution of IKs. Furthermore, our results hint towards a role of these N-terminal amino-acids in membrane representation of the delayed rectifier channel complex.