Turkish nationalism and the Kurdish question

This article addresses the ways in which Turkish nationalism has perceived the Kurdish question. It is shown that both Turkish nationalism and the Kurdish question have passed through some paradigmatic moments in the twentieth century. This, I argue, has shaped the way that the Kurdish question has been perceived by Turkish nationalism. While the Kurdish question had been seen by Turkish nationalism mostly in terms of a fatal rivalry between the backward, pre-modern and tribal past and the prosperous present in the first half of the century, it was perceived in terms of a tension between the peripheral economy and national market in the fifties and sixties. In the 1970s, the Kurdish unrest was believed to be a product of communist incitement. Despite this impurity in perception, one thing has remained nearly unchanged for Turkish nationalism: Kurds could become Turkish. In other words, Turkish nationalism of the republican era has principally perceived Kurds as future-Turks. However, the signs in circulation at present indicate that the confidence of Turkish nationalism as to Kurds’ potential of becoming Turkish is not as firm as it used to be. At present, Turkish nationalism seems to be getting prepared to abandon its contention that Kurds are future-Turks.     

Community Structure of Archaea in the Water Column above Gas Hydrates in the Gulf of Mexico

Microorganisms play fundamental roles in the ecosystem of the Gulf of Mexico (GOM), yet their vertical distributions along the depth continuum of water column are not well known. In this study, we presented the 16S rDNA sequences and lipid profiles in the context of water chemistry to characterize the archaeal community structure above a gas hydrate mound (MC 118) in GOM. Our results showed that all archaeal sequences were related to unknown species of Crenarchaeota or Euryarchaeota. Phylogenetically, group II –β Euryarchaeota dominated the surface water and mid-depth (400-m) water (74% and 58% of total archaeal species, respectively) whereas the marine group I-γ Crenarchaeota dominated the bottom (869 m) water (61% of total archaeal species). Estimates of the Shannon index showed the highest diversity of planktonic Archaea at the 400 m depth. Glycerol dialkyl glycerol tetraether (GDGT) lipids were detected from the 400- and 869-m depths only and characterized by relatively high abundances of GDGT-5 (crenarchaeol) and GDGT-0. Our studies suggested a possible zonation of archaeal community in the water column, which did not seem to be affected by the possible venting of hydrocarbons from the hydrate location in GOM.     

Cell proliferation is promoted by compressive stress during early stage of chondrogenic differentiation of rat BMSCs

The presence of an appropriate number of viable cells is prerequisite for successive differentiation during chondrogenesis. Chondrogenic differentiation has been reported to be influenced by mechanical stimuli. This research aimed to study the effects of cyclic compressive stress on cell viability of rat bone marrow‐derived MSCs (BMSCs) during chondrogenesis as well as its underlying mechanisms. The results showed that dynamic compression increased cell quantity and viability remarkably in the early stage of chondrogenesis, during which the expression of Ihh, Cyclin D1, CDK4, and Col2α1 were enhanced significantly. Possible signal pathways implicated in the process were explored in our study. MEK/ERK and p38 MAPK were not found to function in this process while BMP signaling seemed to play an important role in the mechanotransduction during chondrogenic proliferation. In conclusion, dynamic compressive stress could enhance cell viability during chondrogenesis, which might be achieved by activating BMP signaling. J. Cell. Physiol. 228: 1935–1942, 2013. © 2013 Wiley Periodicals, Inc.     

Elevated polar ejection forces stabilize kinetochore–microtubule attachments

Chromosome biorientation promotes congression and generates tension that stabilizes kinetochore–microtubule (kt-MT) interactions. Forces produced by molecular motors also contribute to chromosome alignment, but their impact on kt-MT attachment stability is unclear. A critical force that acts on chromosomes is the kinesin-10–dependent polar ejection force (PEF). PEFs are proposed to facilitate congression by pushing chromosomes away from spindle poles, although knowledge of the molecular mechanisms underpinning PEF generation is incomplete. Here, we describe a live-cell PEF assay in which tension was applied to chromosomes by manipulating levels of the chromokinesin NOD (no distributive disjunction; Drosophila melanogaster kinesin-10). NOD stabilized syntelic kt-MT attachments in a dose- and motor-dependent manner by overwhelming the ability of Aurora B to mediate error correction. NOD-coated chromatin stretched away from the pole via lateral and end-on interactions with microtubules, and NOD chimeras with either plus end–directed motility or tip-tracking activity produced PEFs. Thus, kt-MT attachment stability is modulated by PEFs, which can be generated by distinct force-producing interactions between chromosomes and dynamic spindle microtubules.     

TRPC6 channel‐mediated neurite outgrowth in PC12 cells and hippocampal neurons involves activation of RAS/MEK/ERK,PI3K,and CAMKIV signaling

The non‐selective cationic transient receptor canonical 6 (TRPC6) channels are involved in synaptic plasticity changes ranging from dendritic growth, spine morphology changes and increase in excitatory synapses. We previously showed that the TRPC6 activator hyperforin, the active antidepressant component of St. John's wort, induces neuritic outgrowth and spine morphology changes in PC12 cells and hippocampal CA1 neurons. However, the signaling cascade that transmits the hyperforin‐induced transient rise in intracellular calcium into neuritic outgrowth is not yet fully understood. Several signaling pathways are involved in calcium transient‐mediated changes in synaptic plasticity, ranging from calmodulin‐mediated Ras‐induced signaling cascades comprising the mitogen‐activated protein kinase, PI3K signal transduction pathways as well as Ca²⁺/calmodulin‐dependent protein kinase II (CAMKII) and CAMKIV. We show that several mechanisms are involved in TRPC6‐mediated synaptic plasticity changes in PC12 cells and primary hippocampal neurons. Influx of calcium via TRPC6 channels activates different pathways including Ras/mitogen‐activated protein kinase/extracellular signal‐regulated kinases, phosphatidylinositide 3‐kinase/protein kinase B, and CAMKIV in both cell types, leading to cAMP‐response element binding protein phosphorylation. These findings are interesting not only in terms of the downstream targets of TRPC6 channels but also because of their potential to facilitate further understanding of St. John's wort extract‐mediated antidepressant activity.

     

IL‐1β and TNF‐α induce neurotoxicity through glutamate production: a potential role for neuronal glutaminase

Glutaminase 1 is the main enzyme responsible for glutamate production in mammalian cells. The roles of macrophage and microglia glutaminases in brain injury, infection, and inflammation are well documented. However, little is known about the regulation of neuronal glutaminase, despite neurons being a predominant cell type of glutaminase expression. Using primary rat and human neuronal cultures, we confirmed that interleukin‐1β (IL‐1β) and tumor necrosis factor‐α (TNF‐α), two pro‐inflammatory cytokines that are typically elevated in neurodegenerative disease states, induced neuronal death and apoptosis in vitro. Furthermore, both intracellular and extracellular glutamate levels were significantly elevated following IL‐1β and/or TNF‐α treatment. Pre‐treatment with N‐Methyl‐d ‐aspartate (NMDA) receptor antagonist MK‐801 blocked cytokine‐induced glutamate production and alleviated the neurotoxicity, indicating that IL‐1β and/or TNF‐α induce neurotoxicity through glutamate. To determine the potential source of excess glutamate production in the culture during inflammation, we investigated the neuronal glutaminase and found that treatment with IL‐1β or TNF‐α significantly upregulated the kidney‐type glutaminase (KGA), a glutaminase 1 isoform, in primary human neurons. The up‐regulation of neuronal glutaminase was also demonstrated in situ in a murine model of HIV‐1 encephalitis. In addition, IL‐1β or TNF‐α treatment increased the levels of KGA in cytosol and TNF‐α specifically increased KGA levels in the extracellular fluid, away from its main residence in mitochondria. Together, these findings support neuronal glutaminase as a potential component of neurotoxicity during inflammation and that modulation of glutaminase may provide therapeutic avenues for neurodegenerative diseases.     

Disassembly of All SNARE Complexes by N-Ethylmaleimide-sensitive Factor (NSF) Is Initiated by a Conserved 1:1 Interaction between α-Soluble NSF Attachment Protein (SNAP) and SNARE Complex

Vesicle trafficking in eukaryotic cells is facilitated by SNARE-mediated membrane fusion. The ATPase NSF (N-ethylmaleimide-sensitive factor) and the adaptor protein α-SNAP (soluble NSF attachment protein) disassemble all SNARE complexes formed throughout different pathways, but the effect of SNARE sequence and domain variation on the poorly understood disassembly mechanism is unknown. By measuring SNARE-stimulated ATP hydrolysis rates, Michaelis-Menten constants for disassembly, and SNAP-SNARE binding constants for four different ternary SNARE complexes and one binary complex, we found a conserved mechanism, not influenced by N-terminal SNARE domains. α-SNAP and the ternary SNARE complex form a 1:1 complex as revealed by multiangle light scattering. We propose a model of NSF-mediated disassembly in which the reaction is initiated by a 1:1 interaction between α-SNAP and the ternary SNARE complex, followed by NSF binding. Subsequent additional α-SNAP binding events may occur as part of a processive disassembly mechanism.     

Local genetic structure in the critically endangered,cave‐associated perennial herb Primulina tabacum (Gesneriaceae)

The local spatial genetic structures of cave‐associated plants are seldom studied. Given that these plants are mainly confined to small areas in and around the entrances of caves, we hypothesized that they might lack genetic structures at local scales. To test this hypothesis, we sampled two large populations (named D and T) of a critically endangered perennial herb, Primulina tabacum, which is endemic to karst caves in southern China. We analysed nine microsatellite loci and sequenced four chloroplast DNA (cpDNA) intergenic spacer regions to study the genetic diversity and structure within and between both populations. Both populations have distinct genetic characteristics. Samples from two subpopulations in population D showed considerable genetic divergence. This is not consistent with the hypothesis that P. tabacum has a weak genetic structure at a local scale. However, 94% of the individuals in population T shared the same multilocus genotype, which indicates little genetic structure within this population. The contributions of seed flow, pollen flow and (sub)population history to the genetic diversity and structure in each and both populations are discussed. Our study is the first to investigate local genetic diversity and structure in a cave‐associated plant, and provides valuable information for the sustainable conservation of such species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 747–756.     

Assessment of Microbiome Variation During the Perioperative Period in Liver Transplant Patients: a Retrospective Analysis

Understanding the composition of the microbial populations in the intestines of liver transplant patients is important to preventing postoperative infection. We investigated the relationship between the risk of postoperative infection and variation in the predominant fecal microbial composition during the perioperative period. We prospectively analyzed the predominant intestinal microbiome of five asymptomatic adult carriers of hepatitis B virus (as controls without any antibiotics) at four weekly follow-up visits and 12 patients before operation and at three weekly postoperative follow-up visits within the first month. Analysis was by denaturing gradient gel electrophoresis (DGGE) and sequencing with digital processing of DGGE profiles using BioNumerics software. Our results showed that the predominant intestinal microbial diversity decreased substantially in eight patients during the perioperative period. Among these, five patients experienced infection with a postoperative hospital stay of more than 30 days. The rest of the four patients who experienced shorter postoperative hospital stays showed only slight variation in predominant intestinal bacterial composition and temporal stability similar to asymptomatic controls. Postoperative fecal DGGE profiles showed mostly bands assigned to Bacteroides and Firmicutes. We conclude that an empiric prophylaxis strategy that destructs gut microecological balance will not be effective in reducing the risk of postoperative infection. Instead, the destruction of intestinal microbiota might result in the appearance of opportunistic pathogens such as Bifidobacterium dentium which rarely appears in the intestinal DGGE profiles of normal humans. Cognizance of the variation of intestinal microbial profiles during the perioperative period is a critical aspect of caring for liver transplant recipients.