Drosophila RhoGAP68F is a putative GTPase activating protein for RhoA participating in gastrulation

The Rho family small GTPases Rho, Rac, and Cdc42 regulate cell shape and motility through the actin cytoskeleton. These proteins cycle between a GTP-bound “on” state and a GDP-bound “off” state and are negatively regulated by GTPase-activating proteins (GAPs), which accelerate the small GTPase’s intrinsic hydrolysis of bound GTP to GDP. Drosophila RhoGAP68F is similar to the mammalian protein p50RhoGAP/Cdc42GAP, which exhibits strong GAP activity toward Cdc42. We find that, despite the strong similarities between RhoGAP68F and p50RhoGAP/Cdc42GAP, RhoGAP68F is most effective as a GAP for RhoA. These in vitro data are supported by the in vivo analysis of mutants in RhoGAP68F. We demonstrate through the characterization of two alleles of the RhoGAP68F gene that RhoGAP68F participates in gastrulation of the embryo, a morphogenetic event driven by cell constriction that involves RhoA signaling. We propose that RhoGAP68F functions as a regulator of RhoA signaling during gastrulation.     

Mitochondrial DNA signals of late glacial recolonization of Europe from near eastern refugia

Human populations, along with those of many other species, are thought to have contracted into a number of refuge areas at the height of the last Ice Age. European populations are believed to be, to a large extent, the descendants of the inhabitants of these refugia, and some extant mtDNA lineages can be traced to refugia in Franco-Cantabria (haplogroups H1, H3, V, and U5b1), the Italian Peninsula (U5b3), and the East European Plain (U4 and U5a). Parts of the Near East, such as the Levant, were also continuously inhabited throughout the Last Glacial Maximum, but unlike western and eastern Europe, no archaeological or genetic evidence for Late Glacial expansions into Europe from the Near East has hitherto been discovered. Here we report, on the basis of an enlarged whole-genome mitochondrial database, that a substantial, perhaps predominant, signal from mitochondrial haplogroups J and T, previously thought to have spread primarily from the Near East into Europe with the Neolithic population, may in fact reflect dispersals during the Late Glacial period, ～19-12 thousand years (ka) ago.     

Mitochondrial haplogroup C4c: A rare lineage entering America through the ice‐free corridor?

Recent analyses of mitochondrial genomes from Native Americans have brought the overall number of recognized maternal founding lineages from just four to a current count of 15. However, because of their relative low frequency, almost nothing is known for some of these lineages. This leaves a considerable void in understanding the events that led to the colonization of the Americas following the Last Glacial Maximum (LGM). In this study, we identified and completely sequenced 14 mitochondrial DNAs belonging to one extremely rare Native American lineage known as haplogroup C4c. Its age and geographical distribution raise the possibility that C4c marked the Paleo-Indian group(s) that entered North America from Beringia through the ice-free corridor between the Laurentide and Cordilleran ice sheets. The similarities in ages andgeographical distributions for C4c and the previously analyzed X2a lineage provide support to the scenario of a dual origin for Paleo-Indians. Taking into account that C4c is deeply rooted in the Asian portion of the mtDNA phylogeny and is indubitably of Asian origin, the finding that C4c and X2a are characterized by parallel genetic histories definitively dismisses the controversial hypothesis of an Atlantic glacial entry route into North America.     

Assessment of lncRNA DANCR,miR-145-5p and NRAS axis as biomarkers for the diagnosis of colorectal cancer

Molecular Biology Reports - Recent evidence reveals that miRNA sponges neutralize miRNAs activity by binding to miRNAs and sequester them from their relevant targets to regulate expression. The...     

Mitogenomes from Two Uncommon Haplogroups Mark Late Glacial/Postglacial Expansions from the Near East and Neolithic Dispersals within Europe

The current human mitochondrial (mtDNA) phylogeny does not equally represent all human populations but is biased in favour of representatives originally from north and central Europe. This especially affects the phylogeny of some uncommon West Eurasian haplogroups, including I and W, whose southern European and Near Eastern components are very poorly represented, suggesting that extensive hidden phylogenetic substructure remains to be uncovered. This study expanded and re-analysed the available datasets of I and W complete mtDNA genomes, reaching a comprehensive 419 mitogenomes, and searched for precise correlations between the ages and geographical distributions of their numerous newly identified subclades with events of human dispersal which contributed to the genetic formation of modern Europeans. Our results showed that haplogroups I (within N1a1b) and W originated in the Near East during the Last Glacial Maximum or pre-warming period (the period of gradual warming between the end of the LGM, ∼19 ky ago, and the beginning of the first main warming phase, ∼15 ky ago) and, like the much more common haplogroups J and T, may have been involved in Late Glacial expansions starting from the Near East. Thus our data contribute to a better definition of the Late and postglacial re-peopling of Europe, providing further evidence for the scenario that major population expansions started after the Last Glacial Maximum but before Neolithic times, but also evidencing traces of diffusion events in several I and W subclades dating to the European Neolithic and restricted to Europe.     

Synthesis and Characterization of a Novel Extracellular Biogenic Manganese Oxide (Bixbyite-like Mn2O3) Nanoparticle by Isolated Acinetobacter sp.

Recently, manganese oxides have been considered in the environmental remediation, MRI diagnosis and drug and pharmaceutical industries. Different numbers of physicochemical and biological methods have been reported for the preparation of nanoscale manganese oxides. Although manganese oxide biogenesis by bacterial species has been recognized as the major Mn-oxidizing agent in nature, in this research, for first time, we demonstrated the process which used to produce bixbyite-like Mn(2)O(3) nanoparticles by isolated aerobic bacterium from Persian Gulf water. The 16SRNA sequencing showed that this isolate belong to a gram-negative Acinetobacter which produced nano Mn-oxide crystal particle. Characterization of complement morphology, size and chemical structure of these particles were determined by TEM, SEM, EDAX, XRD and FTIR. The data showed that this bacterium could produce nanosized extracellular bixbyite-like Mn(2)O(3) which depend on enzymatic pathway.     

Sublethal concentration of H<Subscript>2</Subscript>O<Subscript>2</Subscript> enhances the protective effect of mesenchymal stem cells in rat model of spinal cord injury

Objective

To investigate the effect of H₂O₂ on the migration and antioxidant defense of mesenchymal stem cells (MSCs) and the neurotrophic effects of H₂O₂-treated MSCs on spinal cord injury (SCI).

Results

Sublethal concentrations of H₂O₂ decreased cell migration and expression of CXCR4 and CCR2 as well as Nrf2 expression in MSCs. In the second phase, transplantation of treated and untreated MSCs to SCI caused minor changes in locomotor dysfunction. There was a significantly difference between cell-treated and spinal cord injury groups in expression of BDNF (brain-derived neurotrophic factor). Transplantation of H₂O₂-treated cells caused an increase in BDNF expression compared to non-treated cells.

Conclusion

Transplantation of H₂O₂-treated stem cells may have protective effects against SCI through by increasing neurotrophic factors.