The purpose of this study was to investigate the effects of astragalus polysaccharides (APS) on the proliferation and apoptosis of bone marrow mesenchymal stem cells (BMSCs) induced by X-ray ...radiation-induced A549 cells bystander effect (RIBE), and to explore their mechanisms. In this study, APS increased the reduced cell proliferation rate induced by RIBE and inhibiting the apoptosis of bystander cells. In terms of mechanism, APS up-regulates the proteins Bcl-2, Bcl-xl, and down-regulates the proteins Bax and Bak, which induces a decrease in mitochondrial membrane potential, which induces the release of Cyt-c and AIF, which leads to caspase-dependent and caspase-independent pathway to cause apoptosis. In addition, we believe that ROS may be the main cause of these protein changes. APS can inhibit the generation of ROS in bystander cells and thus inhibit the activation of the mitochondrial pathway, further preventing cellular damage caused by RIBE.
Radiation-induced bystander effects (RIBE) are discussed as relevant processes during radiotherapy. Irradiated cells are suggested to release growth-inhibitory/DNA-damaging factors transported to ...non-irradiated cells. However, the molecular nature of this phenomenon has not yet been resolved. We aimed at identifying the growth-inhibitory factor(s) transmitted to non-irradiated cells.
RIBE-competent PC3 cells were used to produce conditioned medium (CM) after exposure to ionizing radiation. Indicator cells were incubated with CM and clonogenic survival as well as cell proliferation were determined as endpoints. A549 indicator cells exhibited a bystander effect upon incubation with CM from irradiated PC3 cells. This bystander effect was not due to DNA-damaging factors, but a radiation-triggered reduction of mitogenic/clonogenic activity present in CM.
Several tumor cells, but not normal fibroblasts secrete this factor, whose release is reduced by irradiation. We identified L-Plastin to be responsible for the mitogenic/clonogenic activity. Removal of L-Plastin from CM by immunoprecipitation or siRNA-mediated knockdown of L-Plastin expression resulted in loss or reduction of mitogenic/clonogenic activity transmitted via CM, respectively. Exosome-transported L-Plastin was constitutively Ser5-phosphorylated, indicative of its bioactive conformation.
In summary, we observed production and exosomal secretion of L-Plastin by cancer cells. Via exosome-transmitted L-Plastin, tumors induce clonogenic and mitogenic activity in cancer and normal cells of the tumor microenvironment. Irradiation inhibits L-Plastin production targeting both cancer cells and the tumor niche and may explain the high impact of radiotherapy in tumor control.
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•Bystander cells have reduced clonogenic survival, but no increase in DNA damage.•L-Plastin exerts strong clonogenic activity in an autocrine and paracrine manner.•Different malignant cells, but not normal fibroblasts secrete clonogenic L-Plastin.•Reduced exosomal L-Plastin is responsible for the observed bystander effect.•Exosomal L-Plastin is constitutively phosphorylated at Ser5.
Magnetic tunneling junction (MTJ) materials such as CoFeB, Co, Pt, MgO, and the hard mask material such as W and TiN were etched with a reactive ion beam etching (RIBE) system using H2/NH3. By using ...gas mixtures of H2 and NH3, especially with the H2/NH3( 2:1) ratio, higher etch rates of MTJ related materials and higher etch selectivities over mask materials (>30) could be observed compared to those etching using pure H2( no etching) and NH3. In addition, no significant chemical and physical damages were observed on etched magnetic materials surfaces and, for CoPt and MTJ nanoscale patterns etched by the H2/NH3( 2:1) ion beam, highly anisotropic etch profiles >83° with no sidewall redeposition could be observed. The higher etch rates of magnetic materials such as CoFeB by the H2/NH3( 2:1) ion beam compared to those by H2 ion beam or NH3 ion beam are believed to be related to the formation of volatile metal hydrides (MH, M = Co, Fe, etc) through the reduction of M-NHx( x = 1 ∼ 3) formed in the CoFeB surface by the exposure to NH3 ion beam. It is believed that the H2/NH3 RIBE is a suitable technique in the etching of MTJ materials for the next generation nanoscale spin transfer torque magnetic random access memory (STT-MRAM) devices.
We show that every graded nilpotent Lie group G of step r, equipped with a left invariant metric homogeneous with respect to the dilations induced by the grading, (this includes all Carnot groups ...with Carnot-Caratheodory metric) is Markov p-convex for all p∈2r,∞). We also show that this is sharp whenever G is a Carnot group with r≤3, a free Carnot group, or a jet space group; such groups are not Markov p-convex for any p∈(0,2r). This continues a line of research started by Li who proved this sharp result when G is the Heisenberg group. As corollaries, we obtain new estimates on the non-biLipschitz embeddability of some finitely generated nilpotent groups into nilpotent Lie groups of lower step. Sharp estimates of this type are known when the domain is the Heisenberg group and the target is a uniformly convex Banach space or L1, but not when the target is a nonabelian nilpotent group.
Recent discoveries of rapid changes in the atmospheric
C concentration linked to solar particle events have spurred the construction of new radiocarbon annual calibration datasets
. With these ...datasets, radiocarbon dating becomes relevant for urban sites, which require dates at higher resolution than previous calibration datasets could offer. Here we use a single-year radiocarbon calibration curve to anchor the archaeological stratigraphy of a Viking Age trade centre in time. We present absolutely dated evidence for artefact finds charting the expansion of long-distance trade from as far away as Arctic Norway and the Middle East, which we linked to the beginning of the Viking Age at AD 790 ± 10. The methods developed here enable human interactions and cultural, climatic and environmental changes to be compared in archaeological stratigraphies worldwide.
Alohtona fauna parazita slatkovodnih vrsta riba nije detaljno istražena u Republici Hrvatskoj unatoč dugoj povijesti unosa i prijenosa stranih vrsta riba u kopnene vode. Negativne posljedice za ...proizvodnju u akvakulturi i divlje vrste riba često su povezivane s unosom alohtonih vrsta parazita. Stoga ovaj članak nastoji izložiti povijesni pregled lokacija, vremenskih perioda i načina unosa alohtonih vrsta parazita riba u kopnene vode i time sastaviti listu vrsta. Ukupno, 16 alohtonih vrsta parazita zabilježeni su u kopnenim vodama Republike Hrvatske, a ribnjačarstva i ribogojilišta su utvrđena kao početne točke njihovog unosa. Međutim, postoji malo objavljenih podataka o ukupnoj prevalenciji infekcija, kao i ekonomskom utjecaju na akvakulturnu proizvodnju. Osim toga, ograničene informacije su dostupne o prisutnosti i potencijalnom ekološkom utjecaju egzotičnih parazita na autohtone vrste, posebno na endemsku ihtiofaunu u područjima visoke biološke raznolikosti, poput vodenih tijela Jadranskog slijeva. Stoga, postoji žurna i nužna potreba za multidisciplinarni pristup u suradnji između različitih dionika, uključujući državne institucije i znanstvene institucije u biološkoj, poljoprivrednoj i u veterinarskoj disciplini te sektora proizvodnje, s ciljem opsežnih istraživanja kako bi se utvrdio potencijalni utjecaj na proizvodnju akvakulture te autohtone populacije riba visoke konzervacijske vrijednosti.
•Cell cycle status of irradiated cells was involved in the bystander effect induced by carbon ions.•Targeted cells in G2-M phase had the largest contribution to the bystander effect.•DNA-PKcs and ATM ...co-regulated radiation induced G2-M phase-related bystander effect.
Accumulated evidence has shown that radiation-induced bystander effect (RIBE) may have significant implications to the efficiency of radiotherapy. Although cellular radiosensitivity relies on cell cycle status, it is largely unknown how about the relationship between RIBE and cell cycle distribution, much less the underlying mechanism. In the present study, the lung cancer A549 cells were synchronized into different cell cycle phases of G1, S and G2/M and irradiated with high linear energy transfer (LET) carbon ions. By treating nonirradiated cells with the conditioned medium from these irradiated cells, it was found that the G2-M phase cells had the largest contribution to RIBE. Meanwhile, the activity of DNA-PKcs but not ATM was increased in the synchronized G2-M phase cells in spite of both of them were activated in the asynchronous cells after carbon ion irradiation. When the G2-M phased cells were transferred with DNA-PKcs siRNA and ATM siRNA individually or treated with an inhibitor of either DNA-PKcs or ATM before carbon ion irradiation, the RIBE was effectively diminished. These results provide new evidence linking cell cycle to bystander responses and demonstrate that DNA-PKcs and ATM are two associated factors in co-regulating G2-M phase-related bystander effects.
Micro‐X‐ray fluorescence (XRF) screening of 244 glass sherds from Ribe, Denmark, identified 23 wood ash glasses. The closely dated finds pinpoint the arrival of the earliest wood ash glass produced ...in Western Europe in this important North Sea trading hub. This glass type was absent among glass from 700 to 790 CE but feature strongly from 790 to 810 CE. Electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) analysis of 24 glasses show the presence of four types. We show the strengths of classifying wood ash glass based on the glass‐producing sands and conclude that the earliest production took place on a considerable scale and had a major impact on glass circulation in Northern Europe in the ninth century.
The radiation-induced bystander effect (RIBE) is the initiation of biological end points in cells (bystander cells) that are not directly traversed by an incident-radiation track, but are in close ...proximity to cells that are receiving the radiation. RIBE has been indicted of causing DNA damage via oxidative stress, besides causing direct damage, inducing tumorigenesis, producing micronuclei, and causing apoptosis. RIBE is regulated by signaling proteins that are either endogenous or secreted by cells as a means of communication between cells, and can activate intracellular or intercellular oxidative metabolism that can further trigger signaling pathways of inflammation. Bystander signals can pass through gap junctions in attached cell lines, while the suspended cell lines transmit these signals via hormones and soluble proteins. This review provides the background information on how reactive oxygen species (ROS) act as bystander signals. Although ROS have a very short half-life and have a nanometer-scale sphere of influence, the wide variety of ROS produced via various sources can exert a cumulative effect, not only in forming DNA adducts but also setting up signaling pathways of inflammation, apoptosis, cell-cycle arrest, aging, and even tumorigenesis. This review outlines the sources of the bystander effect linked to ROS in a cell, and provides methods of investigation for researchers who would like to pursue this field of science.