Haplotypes, median networks, and diagnostic characters as tools to elucidate the intraspecific genetic and taxonomic structure of bumblebees, with a description of Bombus cryptarum pallidocinctus new subspecies (Hymenoptera: Apidae: Bombus).

Ein Alignment von 168 Sequenzen mitochondrialer DNA von Bombus cryptarum liefert 29 Haplotypen. Ein Median-Network zeigt fünf klar abgrenzbare Cluster, die Haplogruppen (HG) A-E, die durch diagnostische Positionen definiert werden. Vier dieser HG lassen sich bekannten Taxa zuordnen HG-A = B. cryptarum cryptarum, HG-B = B. cryptarum florilegus, HG-D = B. cryptarum albocinctus, und HG-E = B. cryptarum moderatus. Die Haplogruppe C entspricht einem neuen Taxon B. cryptarum pallidocinctus im Rang einer Unterart. Diese neue Unterart wird beschrieben. Die Verbreitung der Eurasiatischen Taxa wird untersucht und die Folgerungen aus Median-Network und geographischer Verbreitung für die mögliche Phylogenie werden diskutiert.StichwörterHymenoptera, Apidae, Bombus, mitochondrial DNA, new subspecies, geographic distributionNomenklatorische Handlungencryptarum pallidocinctus Bertsch et al., 2014 (Bombus), subspec. n.An alignment of 168 sequences of mitochondrial DNA of Bombus cryptarum reveals 29 haplotypes. A median network shows five distinct clusters, haplogroups (HG) A-E, which can be defined by diagnostic characters. Four of these HGs can be assigned to well-known taxa: HG-A = B. cryptarum cryptarum; HG-B = B. cryptarum florilegus; HG-D = B. cryptarum albocinctus; and HG-E = B. cryptarum moderatus. Haplogroup C represents a new taxon B. cryptarum pallidocinctus in the rank of a subspecies. This new subspecies is described. The geographic distribution of the Eurasiatic taxa is described and the implications of geographic distribution and median network for the phylogeny are discussed.KeywordsHymenoptera, Apidae, Bombus, mitochondrial DNA, new subspecies, geographic distributionNomenclatural Actscryptarum pallidocinctus Bertsch et al., 2014 (Bombus), subspec. n

A phylogenetic framework for the North American bumblebee species of the subgenus Bombus sensu stricto (Bombus affinis, B. franklini, B. moderatus, B. occidentalis & B. terricola) based on mitochondrial DNA markers. (Hymenoptera: Apidae: Bombus).

Königinnen der vier Taxa Bombus affinis, B. moderatus, B. occidentalis and B. terricola wurden an verschiedenen Orten quer durch Nordamerika gefangen. Zusätzlich wurden Männchen von B. franklini, B. occidentalis und B. terricola gesammelt. Mitochondriale Cytochrome Oxidase Untereinheit I (COI) von 25 Proben wurde sequenziert (Teilsequenzen 1005 bp Länge). Die Divergenz der Sequenzen zwischen den Taxa beträgt 30–50 Basen-Substitutionen und die Tamura-Nei Genetische Distanz 0.05–0.13, während innerhalb der Taxa die Divergenz nur 1 bis 2 Basen-Substitutionen beträgt und die Tamura-Nei Genetische Distanz 0.001–0.002. Da die COI Sequenzen keine Lücken aufweisen, können die einzelnen Nukleotide wie homologe Positionen verwendet werden. Jedes Taxon besitzt 8–20 eigene Substitutionen, die als dia­gnostische Positionen verwendet werden können, um das Taxon zu charakterisieren. Das Phylogramm zeigt drei klar getrennte Cluster: B. moderatus, konspezifisch mit der ostasiatischen B. albocinctus, das Artenpaar B. affinis – B. franklini locker verwandt mit der eurasiatischen B. lucorum, und das Artenpaar B. terricola – B. occidentalis ohne Beziehungen zu irgendwelchen Arten der Alten Welt.Queens of Bombus affinis, B. moderatus, B. occidentalis and B. terricola were collected from different localities throughout North America. In addition, males of B. franklini, B. occidentalis and B. terricola were collected. Mitochondrial cytochrome oxidase subunit I (COI) was sequenced from 24 specimens (Partial sequences length 1005 bp). Interspecific sequence divergence was about 30–50 base substitutions and approximately 0.05–0.13 in Tamura-Nei genetic distance, whereas the intraspecific sequence divergence was only 1–2 base substitutions and about 0.001–0.002 in Tamura-Nei genetic distance. Because there are no gaps in the alignments of the COI sequences, single nucleotide sites can be used as positional homologies. Each taxon is characterised by about 8 to 20 substitutions, which are unique (“private”) and can be used as diagnostic characters to define and identify this taxon. Three clusters in the topology of the phylogenetic tree were obtained: B. moderatus, which is con-specific to the East Asian B. albocinctus, a species pair B. affinis – B. franklini somehow related to the Eurasian B. lucorum and a species pair B. terricola – B. occidentalis without obvious connection to any Old World species

Phylogenetic relationships of the bumblebees Bombus moderatus, B. albocinctus, B. burjaeticus, B. florilegus and B. cryptarum based on mitochondrial DNA markers: a complex of closely related taxa with circumpolar distribution. (Hymenoptera: Apidae: Bombus).

Königinnen von Bombus moderatus aus Alaska/USA und Alberta/Canada und von B. burjaeticus and B. patagiatus aus dem Russischen Transbaikal wurden an verschiedenen Orten im Frühjahr gefangen, um künstliche Kolonien zu züchten. Zusätzlich wurden Männchen von B. florilegus in Hokkaido/Japan gesammelt. Teilsequenzen (Länge 1005 bp) mitochondrialer Cytochrome Oxidase Untereinheit I (COI) wurde sequenziert. Zum Vergleich wurden auch Museumsproben von B. albocinctus und B. burjaeticus sequenziert. Die Divergenz der Sequenzen innerhalb der Taxa beträgt 1 bis 2 Basen-Substitutionen und die Tamura-Nei Genetische Distanz 0.001–0.002. Die Divergenz der Sequenzen zwischen B. moderatus, B. albocinctus und B. burjaeticus beträgt nur 1–5 Basen-Substitutionen und die Tamura-Nei Genetische Distanz 0.001–0.005, während die Divergenz der Sequenzen zwischen B. lucorum, B. magnus, B. patagiatus und B. cryptarum 22-44 Basen Substitutionen beträgt und die Tamura-Nei Genetische Distanz 0.027-0.042. Zusätzlich zu den Clustern für B. lucorum, B. magnus und B. patagiatus zeigt die Topologie des Phylogramms (MrBayes Maximum Likelihood Tree) ein umfangreiches Cluster, in dem B. albocinctus, B. burjaeticus, B. moderatus und B. florilegus vereinigt sind. Da die COI Sequenzen keine Lücken aufweisen, können die einzelnen Nukleotide wie homologe Positionen verwendet werden. Jedes Taxon besitzt 8–20 eigene Substitutionen, die als diagnostische Positionen zur Charakterisierung des Taxons verwendet werden können. Die Analyse der diagnostischen Positionen der Taxa bestätigt die Topologie des Maximum Likelihood Phylogramms. Um die Lücke zwischen den östlichsten bekannten Vorkommen von B. cryptarum im Kaukasus und im Elburz und den Vorkommen von B. burjaeticus/ B. albocinctus im Russischen Transbaikal und in Russisch Fernost zu überbrücken, wurden 12 weitere Museumsproben aus Zentralasiatischen Gebirgen und dem Himalaja sequenziert. Durch Analyse der diagnostischen Positionen der teilweise 100 Jahre alten DNA kann gezeigt werden, dass keine dieser Proben zu B. lucorum gehören kann, alle bilden ein Cluster mit den Taxa des cryptarum Komplexes.Spring queens of Bombus moderatus from Alaska/USA and Alberta/Canada, and of B. burjaeticus and B. patagiatus from the Russian Transbaikal region were collected at different localities. In addition, males of B. florilegus were collected from Hokkaido/Japan. Partial sequences (length 1005 bp) of mitochondrial cytochrome oxidase subunit I (COI) were sequenced from specimens from each locality and species. For comparison, museum specimens of B. albocinctus and B. burjaeticus were also sequenced. The intraspecific sequence divergence was only 1–2 base substitutions and about 0.001–0.002 in Tamura-Nei genetic distance. The interspecific sequence divergence between B. moderatus, B. albocinctus and B. burjaeticus was only 1–5 base substitutions and about 0.001–0.005 in Tamura-Nei genetic distance, whereas the sequence divergence between B. lucorum, B. magnus, B. patagiatus and B. cryptarum was about 24–44 base substitutions and approximately 0.027–0.042 in Tamura-Nei genetic distance. The MrBayes maximum likelihood tree generated a tree topology with three separate clusters for B. lucorum, B. magnus and B. patagiatus, and one large cluster which united B. albocinctus, B. burjaeticus, B. moderatus and B. florilegus. Because there are no gaps in the alignments of COI sequences, single nucleotide sites were used as positional homologies. Each taxon was characterised by about 8–20 substitutions which were unique (“private”) and could be used as diagnostic characters to define and identify these taxa. An analysis of the number of diagnostic characters confirmed the clustering of the maximum likelihood tree. To bridge the gap of about 5000 km between the most eastern known localities for B. cryptarum in the Caucasus and Elburz Mountains and B. burjaeticus/ B. albocinctus in the Russian Transbaikal region and the Russian Far East, 12 more museum specimens from the Central Asiatic Mountains and the Himalayas were sequenced. By analysing the diagnostic positions in the sequences of this almost 100-year-old museum DNA, it was shown that none were connected with B. lucorum: they all clustered within the cryptarum-complex taxa

ER Stress-Mediated Apoptosis in a New Mouse Model of Osteogenesis imperfecta

Osteogenesis imperfecta is an inherited disorder characterized by increased bone fragility, fractures, and osteoporosis, and most cases are caused by mutations affecting the type I collagen genes. Here, we describe a new mouse model for Osteogenesis imperfecta termed Aga2 (abnormal gait 2) that was isolated from the Munich N-ethyl-N-nitrosourea mutagenesis program and exhibited phenotypic variability, including reduced bone mass, multiple fractures, and early lethality. The causal gene was mapped to Chromosome 11 by linkage analysis, and a C-terminal frameshift mutation was identified in the Col1a1 (procollagen type I, alpha 1) gene as the cause of the disorder. Aga2 heterozygous animals had markedly increased bone turnover and a disrupted native collagen network. Further studies showed that abnormal proα1(I) chains accumulated intracellularly in Aga2/+ dermal fibroblasts and were poorly secreted extracellularly. This was associated with the induction of an endoplasmic reticulum stress-specific unfolded protein response involving upregulation of BiP, Hsp47, and Gadd153 with caspases-12 and −3 activation and apoptosis of osteoblasts both in vitro and in vivo. These studies resulted in the identification of a new model for Osteogenesis imperfecta, and identified a role for intracellular modulation of the endoplasmic reticulum stress-associated unfolded protein response machinery toward osteoblast apoptosis during the pathogenesis of disease

Dll1 Haploinsufficiency in Adult Mice Leads to a Complex Phenotype Affecting Metabolic and Immunological Processes

BACKGROUND: The Notch signaling pathway is an evolutionary conserved signal transduction pathway involved in embryonic patterning and regulation of cell fates during development and self-renewal. Recent studies have demonstrated that this pathway is integral to a complex system of interactions, involving as well other signal transduction pathways, and implicated in distinct human diseases. Delta-like 1 (Dll1) is one of the known ligands of the Notch receptors. The role of the Notch ligands is less well understood. Loss-of-function of Dll1 leads to embryonic lethality, but reduction of Delta-like 1 protein levels has not been studied in adult stage. METHODOLOGY/PRINCIPAL FINDINGS: Here we present the haploinsufficient phenotype of Dll1 and a missense mutant Dll1 allele (Dll1(C413Y)). Haploinsufficiency leads to a complex phenotype with several biological processes altered. These alterations reveal the importance of Dll1 mainly in metabolism, energy balance and in immunology. The animals are smaller, lighter, with altered fat to lean ratio and have increased blood pressure and a slight bradycardia. The animals have reduced cholesterol and triglyceride levels in blood. At the immunological level a subtle phenotype is observed due to the effect and fine-tuning of the signaling network at the different levels of differentiation, proliferation and function of lymphocytes. Moreover, the importance of the proteolytic regulation of the Notch signaling network emphasized. CONCLUSIONS/SIGNIFICANCE: In conclusion, slight alterations in one player of Notch signaling alter the entire organism, emphasizing the fine-tuning character of this pathway in a high number of processes

From Dynamic Expression Patterns to Boundary Formation in the Presomitic Mesoderm

The segmentation of the vertebrate body is laid down during early embryogenesis. The formation of signaling gradients, the periodic expression of genes of the Notch-, Fgf- and Wnt-pathways and their interplay in the unsegmented presomitic mesoderm (PSM) precedes the rhythmic budding of nascent somites at its anterior end, which later develops into epithelialized structures, the somites. Although many in silico models describing partial aspects of somitogenesis already exist, simulations of a complete causal chain from gene expression in the growth zone via the interaction of multiple cells to segmentation are rare. Here, we present an enhanced gene regulatory network (GRN) for mice in a simulation program that models the growing PSM by many virtual cells and integrates WNT3A and FGF8 gradient formation, periodic gene expression and Delta/Notch signaling. Assuming Hes7 as core of the somitogenesis clock and LFNG as modulator, we postulate a negative feedback of HES7 on Dll1 leading to an oscillating Dll1 expression as seen in vivo. Furthermore, we are able to simulate the experimentally observed wave of activated NOTCH (NICD) as a result of the interactions in the GRN. We esteem our model as robust for a wide range of parameter values with the Hes7 mRNA and protein decays exerting a strong influence on the core oscillator. Moreover, our model predicts interference between Hes1 and HES7 oscillators when their intrinsic frequencies differ. In conclusion, we have built a comprehensive model of somitogenesis with HES7 as core oscillator that is able to reproduce many experimentally observed data in mice

Cytoplasmic Thioredoxin Reductase Is Essential for Embryogenesis but Dispensable for Cardiac Development

Two distinct thioredoxin/thioredoxin reductase systems are present in the cytosol and the mitochondria of mammalian cells. Thioredoxins (Txn), the main substrates of thioredoxin reductases (Txnrd), are involved in numerous physiological processes, including cell-cell communication, redox metabolism, proliferation, and apoptosis. To investigate the individual contribution of mitochondrial (Txnrd2) and cytoplasmic (Txnrd1) thioredoxin reductases in vivo, we generated a mouse strain with a conditionally targeted deletion of Txnrd1. We show here that the ubiquitous Cre-mediated inactivation of Txnrd1 leads to early embryonic lethality. Homozygous mutant embryos display severe growth retardation and fail to turn. In accordance with the observed growth impairment in vivo, Txnrd1-deficient embryonic fibroblasts do not proliferate in vitro. In contrast, ex vivo-cultured embryonic Txnrd1-deficient cardiomyocytes are not affected, and mice with a heart-specific inactivation of Txnrd1 develop normally and appear healthy. Our results indicate that Txnrd1 plays an essential role during embryogenesis in most developing tissues except the heart

Virtual expression patterns as simulated <i>in silico</i> by the proposed gene regulatory network.

<p>Expression patterns are shown at three different time points in one oscillation cycle for one half of the PSM. Cytoplasmic mRNAs are colored in blue, proteins in red. The tail bud is growing from left to right. When EPHA4 concentration has reached a certain threshold, the virtual cells change their shape to symbolize epithelialization at the forming somite border.</p

Snapshots of virtual expression patterns for <i>Hes7</i> mRNA in simulations of the growing PSM.

<p>The posterior-to-anterior FGF8 gradient is coupled to the HES7 decay. One time step equals 0.1 minute. From left to right shown are the cases of 100% noise added during division of cells in the growth zone of the PSM without (shown also in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003843#pcbi.1003843.s009" target="_blank">movie S3</a>) and with (shown also in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003843#pcbi.1003843.s010" target="_blank">movie S4</a>) D/N cis-inhibition. Snapshots are also displayed for simulation runs wherein the disturbance of oscillator consonance is caused by shutting down the transcription of the core oscillator genes during mitosis. Shown are the cases of 20 min shutdown of the transcription during cell division in the growth zone of the PSM without (shown also in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003843#pcbi.1003843.s012" target="_blank">movie S6</a>) and with (shown also in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003843#pcbi.1003843.s011" target="_blank">movie S5</a>) D/N cis-inhibition. Cells are colored orange in the simulations as long as transcription of their genes is shut down.</p

<i>Mesp2</i> expression without <i>Hes7</i>.

<p>The virtual expression patterns for <i>Mesp2</i> (cytoplasmic mRNA) are shown at five different time points in one complete and part of the following oscillation cycle. Panels on the left show the wild-type situation, panels on the right show <i>Mesp2</i> expression when <i>Hes7</i> is eliminated from the GRN (virtual <i>Hes7</i> knock-out). The tail bud of the PSM is growing from left to right.</p