Silencing of MicroRNA-21 Confers Radio-Sensitivity through Inhibition of the PI3K/AKT Pathway and Enhancing Autophagy in Malignant Glioma Cell Lines

Radiation is a core part of therapy for malignant glioma and is often provided following debulking surgery. However, resistance to radiation occurs in most patients, and the underlying molecular mechanisms of radio-resistance are not fully understood. Here, we demonstrated that microRNA 21 (miR-21), a well-known onco-microRNA in malignant glioma, is one of the major players in radio-resistance. Radio-resistance in different malignant glioma cell lines measured by cytotoxic cell survival assay was closely associated with miR-21 expression level. Blocking miR-21 with anti-miR-21 resulted in radio-sensitization of U373 and U87 cells, whereas overexpression of miR-21 lead to a decrease in radio-sensitivity of LN18 and LN428 cells. Anti-miR-21 sustained γ-H2AX DNA foci formation, which is an indicator of double-strand DNA damage, up to 24 hours and suppressed phospho-Akt (ser473) expression after exposure to γ-irradiation. In a cell cycle analysis, a significant increase in the G₂/M phase transition by anti-miR-21 was observed at 48 hours after irradiation. Interestingly, our results showed that anti-miR-21 increased factors associated with autophagosome formation and autophagy activity, which was measured by acid vesicular organelles, LC3 protein expression, and the percentage of GFP-LC3 positive cells. Furthermore, augmented autophagy by anti-miR-21 resulted in an increase in the apoptotic population after irradiation. Our results show that miR-21 is a pivotal molecule for circumventing radiation-induced cell death in malignant glioma cells through the regulation of autophagy and provide a novel phenomenon for the acquisition of radio-resistance.     

Bat species diversity in a lake archipelago in central Sweden

The bat fauna of 35 islands in a large lake in central Sweden were examined using ultrasound detectors. We tested the hypothesis that there is no difference in species number between the mainland and the island fauna. Eight species were found. Species numbers were analysed against island area, area of some habitats (coniferous forest, deciduous forest, semi-open habitats and open habitats), degree of isolation (distance from mainland and from stepping stones) and time spent searching for bats. Species number increased with area of deciduous forest. Presence of houses tended to increase species number. There seems to be a negative relationship between species number and degree of isolation (nearly significant). The results suggest that at least three species, Myotis brandti (Eversmann, 1845), M. mystacinus (Kuhl, 1819) and Plecotus auritus (Linnaeus, 1758), are negatively affected by forest patchiness. These species occurred mainly on large islands. Thus, the results do not support the hypothesis. The reasons why some species avoid open habitats are discussed.     

Study on four genera of Diplazontinae (Hymenoptera: Ichneumonidae) in South Korea with description of two new species

Of 16 genera of the subfamily Diplazontinae occurring in the Eastern Palearctic region, 11 were previously recognized from South Korea. In previous studies we reviewed eight Diplazontinae genera were reviewed. In this current paper, one genus, Enizemum Förster, is recorded from this country for the first time with one newly described species, E. nigrocoxatum Balueva and Lee sp. nov. Also other three genera, Homotropus Förster, Syrphoctonus Förster and Syrphophilus Dasch, are reviewed here. Here we provide key and diagnosis to eight species of Homotropus including one new species, Homotropus sepiatus Balueva and Lee sp. nov. , and key and diagnosis to two species of genus Syrphoctonus and two species of genus Syrphophilus.     

Production of exopolysaccharides by submerged mycelial culture of a mushroom Tremella fuciformis

The optimization of submerged culture conditions for mycelial growth and exopolysaccharide (EPS) production in an edible mushroom Tremella fuciformis was studied in shake flasks and bioreactors. The temperature of 28 degrees C and pH 8 in the beginning of fermentation in agitated flasks was the most efficient condition to obtain maximum mycelial biomass and EPS. The optimal medium constituents were as follows (gL(-1)): glucose 20, tryptone 2, KH(2)PO(4) 0.46, K(2)HPO(4) 1 and MgSO(4).7H(2)O 0.5. The fungus was cultivated under various agitation and aeration conditions in a 5L stirred-tank bioreactor. The maximum cell mass and EPS production were obtained at a relatively high agitation speed of 200 rpm and at an aeration rate of 2 vvm. The flow behavior of the fermentation broth was Newtonian and the maximum apparent viscosity (35 cP) was observed at a highly aerated condition (2 vvm). The EPS productivity in an airlift reactor was higher than that in the stirred-tank reactor. The morphological study revealed that the fungus grows in mainly three different yeast-like forms: ovoid, elongated, and double yeast forms. The high population of the elongated yeast has a very close relationship to high EPS production. The EPS were protein-bound polysaccharides consisted of mainly mannose, xylose, and fucose. The molecular weights of EPS were determined to be (1.3-1.5)x10(6).     

Expression and regulation of theRSI-1 gene during lateral root initiation

The tomato geneRSI-1 was previously identified as a molecular marker for auxin-induced lateral root initiation. We have further characterized the expression mode of theRSI-1 gene in tomato andArabidopsis thaliana. Northern blot analyses revealed that the gene was induced specifically by auxin in tomato roots and hypocotyls. For experiments with transgenic plants, the 5′ flanking region of theRSI-1 gene was linked to a GUS reporter gene, then transformed into tomato andArabidopsis. In these transgenic tomato plants, GUS activity was detected at the sites of initiation for lateral and adventitious roots. Expression of the fusion gene was auxin-dependent and tissue-specific. This was consistent with results from the northern blot analyses. In transgenicArabidopsis, the overall expression pattern of theRSI-GUS gene, including tissue specificity and auxin inducibility, was comparable to that in transgenic tomato seedlings. These results indicate that an identical regulatory mechanism for lateral root initiation might be conserved in both plants. Thus, the expression mode of theRSI-CUS gene inArabidopsis mutants defective in lateral root development should be investigated to provide details of this process.     

Structural Brain Changes after Traditional and Robot-Assisted Multi-Domain Cognitive Training in Community-Dwelling Healthy Elderly

The purpose of this study was to investigate if multi-domain cognitive training, especially robot-assisted training, alters cortical thickness in the brains of elderly participants. A controlled trial was conducted with 85 volunteers without cognitive impairment who were 60 years old or older. Participants were first randomized into two groups. One group consisted of 48 participants who would receive cognitive training and 37 who would not receive training. The cognitive training group was randomly divided into two groups, 24 who received traditional cognitive training and 24 who received robot-assisted cognitive training. The training for both groups consisted of daily 90-min-session, five days a week for a total of 12 weeks. The primary outcome was the changes in cortical thickness. When compared to the control group, both groups who underwent cognitive training demonstrated attenuation of age related cortical thinning in the frontotemporal association cortices. When the robot and the traditional interventions were directly compared, the robot group showed less cortical thinning in the anterior cingulate cortices. Our results suggest that cognitive training can mitigate age-associated structural brain changes in the elderly.

Trial Registration

ClnicalTrials.gov NCT01596205     

Ethanol impairs insulin-stimulated neuronal survival in the developing brain: role of PTEN phosphatase

Gestational exposure to ethanol causes fetal alcohol syndrome, which is associated with cerebellar hypoplasia. Previous in vitro studies demonstrated ethanol-impaired neuronal survival with reduced signaling through the insulin receptor (IRbeta). We examined insulin signaling in an experimental rat model of chronic gestational exposure to ethanol in which the pups exhibited striking cerebellar hypoplasia with increased apoptosis. Immunoprecipitation and Western blot analyses detected reduced levels of tyrosyl-phosphorylated IRbeta, tyrosyl-phosphorylated insulin receptor substrate-1 (IRS-1), and p85-associated IRS-1 but no alterations in IRbeta, IRS-1, or p85 protein expression in cerebellar tissue from ethanol-exposed pups. In addition, ethanol exposure significantly reduced the levels of total phosphoinositol 3-kinase, Akt kinase, phospho-BAD (inactive), and glyceraldehyde-3-phosphate dehydrogenase and increased the levels of glycogen synthase kinase-3 activity, activated BAD, phosphatase and tensin homolog deleted in chromosome 10 (PTEN) protein, and PTEN phosphatase activity in cerebellar tissue. Cerebellar neurons isolated from ethanol-exposed pups had reduced levels of insulin-stimulated phosphoinositol 3-kinase and Akt kinase activities and reduced insulin inhibition of PTEN and glycogen synthase kinase-3 activity. The results demonstrate that cerebellar hypoplasia produced by chronic gestational exposure to ethanol is associated with impaired survival signaling through insulin-regulated pathways, including failure to suppress PTEN function.     

Molecular,genetic and evolutionary analysis of a paracentric inversion in Arabidopsis thaliana

Chromosomal inversions can provide windows onto the cytogenetic, molecular, evolutionary and demographic histories of a species. Here we investigate a paracentric 1.17‐Mb inversion on chromosome 4 of Arabidopsis thaliana with nucleotide precision of its borders. The inversion is created by Vandal transposon activity, splitting an F‐box and relocating a pericentric heterochromatin segment in juxtaposition with euchromatin without affecting the epigenetic landscape. Examination of the RegMap panel and the 1001 Arabidopsis genomes revealed more than 170 inversion accessions in Europe and North America. The SNP patterns revealed historical recombinations from which we infer diverse haplotype patterns, ancient introgression events and phylogenetic relationships. We find a robust association between the inversion and fecundity under drought. We also find linkage disequilibrium between the inverted region and the early flowering Col‐FRIGIDA allele. Finally, SNP analysis elucidates the origin of the inversion to South‐Eastern Europe approximately 5000 years ago and the FRI‐Col allele to North‐West Europe, and reveals the spreading of a single haplotype to North America during the 17th to 19th century. The ‘American haplotype’ was identified from several European localities, potentially due to return migration.