Confined migration induces heterochromatin formation and alters chromatin accessibility

During migration, cells often squeeze through small constrictions, requiring extensive deformation. We hypothesized that the nuclear deformation associated with such confined migration could alter chromatin organization and function. Studying cells migrating through collagen matrices and microfluidic devices that mimic interstitial spaces in vivo, we found that confined migration results in increased H3K9me3 and H3K27me3 heterochromatin marks that persist for several days. This "confined migration-induced heterochromatin" (CMiH) was distinct from heterochromatin formation during migration initiation. CMiH predominantly decreased chromatin accessibility at intergenic regions near centromeres and telomeres, suggesting heterochromatin spreading from existing heterochromatin sites. Consistent with the overall decrease in chromatin accessibility, global transcription was decreased during confined migration. Intriguingly, we also identified increased accessibility at promoter regions of genes linked to chromatin silencing, tumor invasion, and DNA damage response. Inhibiting CMiH reduced migration speed, suggesting that CMiH promotes confined migration. Together, our findings indicate that confined migration induces chromatin changes that regulate cell migration and other cellular functions.

Dissolution precipitation creep as a process for the strain localisation in mafic rocks

Unaltered mafic rocks consist of mechanically strong minerals (e.g. pyroxene, plagioclase and garnet) that can be deformed by crystal plastic mechanisms only at high temperatures (>800°C). Yet, many mafic rocks do show extensive deformation by non-brittle mechanisms when they have been subjected to lower temperature conditions. In such cases, the deformation typically is assisted by mineral reactions. Here we show that dissolution-precipitation creep (as a type of diffusion creep) plays a major role in deformation of gabbro lenses at upper amphibolite facies conditions. The Kågen gabbro exposed on south Arnøya is comprised of almost undeformed gabbro lenses with sheared margins wrapping around them. The shearing has taken place at temperatures of 690 ± 25 °C and pressures of 1.0 to 1.1 GPa. This contribution analyses the evolution of the microstructures and fabric of the low strain gabbro to high strain margins. Microstructural and crystallographic preferred orientation (CPO) data indicate that dissolution-precipitation creep is the dominant deformation mechanism, where dissolution of the gabbro took place in reacting phases of clinopyroxene and plagioclase, and precipitation took place in the form of new minerals: new plagioclase and clinopyroxene (with different composition), amphibole, and garnet. Amphibole shows a strong CPO that is primarily controlled by its preferential growth in the stretching direction. Synchronous deformation and mineral reactions of clinopyroxene suggest that mafic rocks can become mechanically weak during a general transformation weakening process, i.e. the interaction of mineral reaction and deformation by diffusion creep. The weakening is directly connected to a fluid-assisted transformation process that facilitates diffusion creep deformation of strong minerals at far lower stresses and temperatures than dislocation creep. Initially strong lithologies can become weak, provided that reactions can proceed during deformation; the transformation process itself is an important weakening mechanism in mafic (and other) rocks, facilitating deformation at low differential stresses and low stress exponents.

Diversification of Cynoglossinae genera (Cynoglosseae-Boraginaceae) in the western Irano-Turanian bioregion

The Irano-Turanian (I-T) bioregion harbours one of the Old world’s greatest repositories of botanical diversity; however, the diversification patterns and the phenotypic evolution of its flora are sorely understudied. The subtribe Cynoglossinae is characteristic of the western I-T bioregion, species–rich both in the desertic lowlands and the more mesic highlands of the Iranian plateau. About 70 species of Cynoglossinae are present in the Iranian plateau, 47 of which are endemic to the plateau.Herein, nuclear ITS and cpDNA rpl32-trnL and trnH–psbA sequences were used to investigate the molecular phylogeny, historical biogeography and ancestral character states of Cynoglossinae. Molecular dating and ancestral range reconstruction analyses indicated that the subtribe Cynoglossinae has initiated its diversification from the eastern part of the western I-T during the mid-Miocene, concomitantly with the uplift of the Pamir and Hindu Kush mountains. Moreover, from the Pliocene onwards the Afghan-India collision and extensive deformation of the Arabia-Eurasia convergence probably promoted allopatric speciation in Cynoglossinae via mostly vicariance events. Evolution of annuals with small nutlets from perennials with large nutlets was accompanied by mesic to desert habitats shifts. Herein, to explain distribution of Cynoglossinae in the western I-T, the congruence between cladogenetic, geological and palaeoclimatic events was investigated.

Multidisciplinary Surgery In Thoracic Wall Reconstruction For Sternal Osteomyelitis

Sternal osteomyelitis and dehisense are a common problem with an incidence rate of 0.5% to 5.0% after major cardiac surgery. However, the management of separation of the sternum in the patient’s thorax remains a challenge for cardiac surgeons and thoracic surgeons using the incision. After cardiac surgery, postop sternal dehiscence and osteomyelitis was developed in the patient. The old steel wires were removed and the sternum was resected due to long-term infection and extensive deformation of the sternum. Pectoralis muscle flaps were partially mobilized and adducted. The large defect was closed using a large prolene patch. Proper sized transversal titanium plates were selected. Due to the sternum bone was severely destroyed by infection, longer transversal titanium plates were chosen to achieve thoracic stability. Healthy tissues were detected on the ribs. A total of 4 titanium plates were placed intermittently. The plates were fixed to the ribs with titanium locking screws. The pectoral muscle flaps adducted to the plates by the plastic surgery team. A total of 3 drains were placed, one in the mediastinum and two between the thoracic wall and muscle structures.

Multidisciplinary Surgery in Thoracic Wall Reconstruction for Sternal Osteomyelitis

Sternal osteomyelitis and dehiscence are a common problem with an incidence rate of 0.5% to 5.0% after major cardiac surgery. However, the management of separation of the sternum in the patient's thorax remains a challenge for cardiac surgeons and thoracic surgeons using the incision. After cardiac surgery, post-op sternal dehiscence and osteomyelitis was developed in the patient. The old steel wires were removed and the sternum was resected due to long-term infection and extensive deformation of the sternum. Pectoralis muscle flaps were partially mobilized and adducted. The large defect was closed using a large prolene patch. Proper sized transversal titanium plates were selected. Due to the sternum bone was severely destroyed by infection, longer transversal titanium plates were chosen to achieve thoracic stability. Healthy tissues were detected on the ribs. A total of 4 titanium plates were placed intermittently. The plates were fixed to the ribs with titanium locking screws. The pectoral muscle flaps adducted to the plates by the plastic surgery team. A total of 3 drains were placed, one in the mediastinum and two between the thoracic wall and muscle structures.

Insight on the anatomy, systematic relationships, and age of the Early Cretaceous ankylopollexian dinosaurDakotadon lakotaensis

Knowledge regarding the early evolution within the dinosaurian clade Ankylopollexia drastically increased over the past two decades, in part because of an increase in described taxa from the Early Cretaceous of North America. These advances motivated the recent completion of extensive preparation and conservation work on the holotype and only known specimen ofDakotadon lakotaensis, a basal ankylopollexian from the Lakota Formation of South Dakota. That specimen (SDSM 8656) preserves a partial skull, lower jaws, a single dorsal vertebra, and two caudal vertebrae. That new preparation work exposed several bones not included in the original description and revealed that other bones were previously misidentified. The presence of extensive deformation in areas of the skull is also noted that influenced inaccuracies in prior descriptions and reconstructions of this taxon. In addition to providing an extensive re-description ofD. lakotaensis, this study reviews previously proposed diagnoses for this taxon, identifies two autapomorphies, and provides an extensive differential diagnosis.Dakotadon lakotaensisis distinct from the only other ankylopollexian taxon known from the Lakota Formation,Osmakasaurus depressus, in the presence of two prominent, anteroposteriorly oriented ridges on the ventral surfaces of the caudal vertebrae, the only overlapping material preserved between these taxa. The systematic relationships ofD. lakotaensisare evaluated using both the parsimony and posterior probability optimality criteria, with both sets of analyses recoveringD. lakotaensisas a non-hadrosauriform ankylopollexian that is more closely related to taxa from the Early Cretaceous (e.g.,Iguanacolossus,Hippodraco, andTheiophytalia) than to more basally situated taxa from the Jurassic (e.g.,Camptosaurus, Uteodon). This taxonomic work is supplemented by field work that relocated the type locality, confirming its provenance from unit L2 (lower Fuson Member equivalent) of the Lakota Formation. Those data, combined with recently revised ages for the members of the Lakota Formation based on charophyte and ostracod biostratigraphy, constrain the age of this taxon to the late Valanginian to early Barremian.

Insight on the anatomy, systematic relationships, and age of the Early Cretaceous ankylopollexian dinosaur Dakotadon lakotaensis

Knowledge regarding the early evolution within the dinosaurian clade Ankylopollexia drastically increased over the past two decades, in part because of an increase in described taxa from the Early Cretaceous of North America. These advances motivated the recent completion of extensive preparation and conservation work on the holotype and only known specimen of Dakotadon lakotaensis, a basal ankylopollexian from the Lakota Formation of South Dakota. That specimen (SDSM 8656) preserves a partial skull, lower jaws, a single dorsal vertebra, and two caudal vertebrae. That new preparation work exposed several bones not included in the original description and revealed that other bones were previously misidentified. The presence of extensive deformation in areas of the skull is also noted that influenced inaccuracies in prior descriptions and reconstructions of this taxon. In addition to providing an extensive re-description of D. lakotaensis, this study reviews previously proposed diagnoses for this taxon, identifies two autapomorphies, and provides an extensive differential diagnosis. Dakotadon lakotaensis is distinct from the only other ankylopollexian taxon known from the Lakota Formation, Osmakasaurus depressus, in the presence of two prominent, anteroposteriorly oriented ridges on the ventral surfaces of the caudal vertebrae, the only overlapping material preserved between these taxa. The systematic relationships of D. lakotaensis are evaluated using both the parsimony and posterior probability optimality criteria, with both sets of analyses recovering D. lakotaensis as a non-hadrosauriform ankylopollexian that is more closely related to taxa from the Early Cretaceous (e.g., Iguanacolossus, Hippodraco, and Theiophytalia) than to more basally situated taxa from the Jurassic (e.g., Camptosaurus, Uteodon). This taxonomic work is supplemented by field work that relocated the type locality, confirming its provenance from unit L2 (lower Fuson Member equivalent) of the Lakota Formation. Those data, combined with recently revised ages for the members of the Lakota Formation based on charophyte and ostracod biostratigraphy, constrain the age of this taxon to the late Valanginian to early Barremian.

Insight on the anatomy, systematic relationships, and age of the Early Cretaceous ankylopollexian dinosaur Dakotadon lakotaensis

Knowledge regarding the early evolution within the dinosaurian clade Ankylopollexia drastically increased over the past two decades, in part because of an increase in described taxa from the Early Cretaceous of North America. These advances motivated the recent completion of extensive preparation and conservation work on the holotype and only known specimen of Dakotadon lakotaensis, a basal ankylopollexian from the Lakota Formation of South Dakota. That specimen (SDSM 8656) preserves a partial skull, lower jaws, a single dorsal vertebra, and two caudal vertebrae. That new preparation work exposed several bones not included in the original description and revealed that other bones were previously misidentified. The presence of extensive deformation in areas of the skull is also noted that influenced inaccuracies in prior descriptions and reconstructions of this taxon. In addition to providing an extensive re-description of D. lakotaensis, this study reviews previously proposed diagnoses for this taxon, identifies two autapomorphies, and provides an extensive differential diagnosis. Dakotadon lakotaensis is distinct from the only other ankylopollexian taxon known from the Lakota Formation, Osmakasaurus depressus, in the presence of two prominent, anteroposteriorly oriented ridges on the ventral surfaces of the caudal vertebrae, the only overlapping material preserved between these taxa. The systematic relationships of D. lakotaensis are evaluated using both the parsimony and posterior probability optimality criteria, with both sets of analyses recovering D. lakotaensis as a non-hadrosauriform ankylopollexian that is more closely related to taxa from the Early Cretaceous (e.g., Iguanacolossus, Hippodraco, and Theiophytalia) than to more basally situated taxa from the Jurassic (e.g., Camptosaurus, Uteodon). This taxonomic work is supplemented by field work that relocated the type locality, confirming its provenance from unit L2 (lower Fuson Member equivalent) of the Lakota Formation. Those data, combined with recently revised ages for the members of the Lakota Formation based on charophyte and ostracod biostratigraphy, constrain the age of this taxon to the late Valanginian to early Barremian.

Insight on the anatomy, systematic relationships, and age of the Early Cretaceous ankylopollexian dinosaur Dakotadon lakotaensis

Knowledge regarding the early evolution within the dinosaurian clade Ankylopollexia drastically increased over the past two decades, in part because of an increase in described taxa from the Early Cretaceous of North America. These advances motivated the recent completion of extensive preparation and conservation work on the holotype and only known specimen of Dakotadon lakotaensis, a basal ankylopollexian from the Lakota Formation of South Dakota. That specimen (SDSM 8656) preserves a partial skull, lower jaws, a single dorsal vertebra, and two caudal vertebrae. That new preparation work exposed several bones not included in the original description and revealed that other bones were previously misidentified. The presence of extensive deformation in areas of the skull is also noted that influenced inaccuracies in prior descriptions and reconstructions of this taxon. In addition to providing an extensive re-description of D. lakotaensis, this study reviews previously proposed diagnoses for this taxon, identifies three autapomorphies, and provides an extensive differential diagnosis. Dakotadon lakotaensis is distinct from the only other ankylopollexian taxon known from the Lakota Formation, Osmakasaurus depressus, in the presence of two prominent, anteroposteriorly oriented ridges on the ventral surfaces of the caudal vertebrae, the only overlapping material preserved between these taxa. The systematic relationships of Dakotadon lakotaensis are evaluated using both the parsimony and posterior probability optimality criteria, with both sets of analyses recovering D. lakotaensis as a non-hadrosauriform ankylopollexian that is more closely related to taxa from the early Cretaceous (e.g., Iguanacolossus, Hippodraco, and Theiophytalia) than to more basally situated taxa from the Jurassic (e.g., Camptosaurus, Uteodon). This taxonomic work is supplemented by field work that relocated the type locality, confirming its provenance from unit L2 (lower Fuson Member equivalent) of the Lakota Formation. Those data, combined with recently revised ages for the members of the Lakota Formation based on charophyte and ostracod biostratigraphy, constrain the age of this taxon to the late Valanginian to early Hauterivian. The only other equivalent-aged ankylopollexian taxon from North America, the poorly known Planicoxa venenica from the Poison Strip Sandstone of Utah, preserves caudal vertebrae that bear the same ventral ridges seen in D. lakotaensis, raising the possibility of a close affinity between these taxa.