| 1. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 2. |
- Li, Fenghong, et al.
(författare)
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Electronic structure and molecular orientation of pentacene thin films on ferromagnetic La0.7Sr0.3MnO3
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 81:20, s. 205415-1-205415-6
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Tidskriftsartikel (refereegranskat)abstract
- Pentacene thin films deposited on a ferromagnetic electrode, La0.7Sr0.3MnO3 (LSMO), have been studied using near-edge x-ray absorption fine structure (NEXAFS), ultraviolet photoemission spectroscopy (UPS), and atomic force microscopy (AFM). Here we present electronic structure and molecular orientation of pentacene thin film on LSMO. No evidence related to covalent bonding or significant charge transfer between pentacene and LSMO has been found in the NEXAFS or UPS results. UPS measurements suggest that the vertical ionization potential of pentacene on LSMO is 4.9 eV. Our results extracted from NEXAFS indicate that molecular long axis of pentacene stands on the LSMO substrate surface with a tilt angle of about 22 degrees +/- 2 degrees between the main molecular axis and the substrate surface normal. AFM images show the terracelike crystalline grain formed by stacking pentacene crystalline layers and a rough crystal-layer spacing of 14-15 angstrom. Findings deduced from UPS, NEXAFS, and AFM consistently demonstrate that pentacene stands on LSMO with a tilt angle.
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| 3. |
- Liu, Wei, et al.
(författare)
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Impact of silver nanoparticles on human cells : effect of particle size
- 2010
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Ingår i: Nanotoxicology. - New York : Informa Healthcare. - 1743-5390 .- 1743-5404. ; 4:3, s. 319-330
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Tidskriftsartikel (refereegranskat)abstract
- This work investigated the cytotoxicities of three silver nanoparticles (SNPs) SNP-5, SNP-20 and SNP-50 with different sizes ( approximately 5 nm, approximately 20 nm and approximately 50 nm) using four human cell models (A549, SGC-7901, HepG2 and MCF-7). Endpoints included cell morphology, cell viability, cellular membrane integrity, oxidative stress and cell cycle progression. Observable deleterious effects on the cell morphologies and membrane integrity were induced by SNP-5 and SNP-20. SNPs elevated the ROS levels in cells and arrested the cells at S phase. Apoptosis occurred for 4-9% of the exposed cells. All these cellular responses as well as EC50 values were found to be size-dependent for the tested SNPs. Ultrastructural observations confirmed the presence of SNPs inside cells. Elemental analysis of silver in cells by ICP-MS showed that smaller nanoparticles enter cells more easily than larger ones, which may be the cause of higher toxic effects. The findings may assist in the design of SNP applications and provide insights into their toxicity.
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| 4. |
- Loth, Daan W, et al.
(författare)
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Genome-wide association analysis identifies six new loci associated with forced vital capacity
- 2014
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 46, s. 669-677
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Tidskriftsartikel (refereegranskat)abstract
- Forced vital capacity (FVC), a spirometric measure of pulmonary function, reflects lung volume and is used to diagnose and monitor lung diseases. We performed genome-wide association study meta-analysis of FVC in 52,253 individuals from 26 studies and followed up the top associations in 32,917 additional individuals of European ancestry. We found six new regions associated at genome-wide significance (P < 5 × 10(-8)) with FVC in or near EFEMP1, BMP6, MIR129-2-HSD17B12, PRDM11, WWOX and KCNJ2. Two loci previously associated with spirometric measures (GSTCD and PTCH1) were related to FVC. Newly implicated regions were followed up in samples from African-American, Korean, Chinese and Hispanic individuals. We detected transcripts for all six newly implicated genes in human lung tissue. The new loci may inform mechanisms involved in lung development and the pathogenesis of restrictive lung disease.
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| 5. |
- Wienecke, Jacob, et al.
(författare)
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Spinal Cord Injury Enables Aromatic l-Amino Acid Decarboxylase Cells to Synthesize Monoamines.
- 2014
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Ingår i: The Journal of Neuroscience. - 1529-2401. ; 34:36, s. 11984-12000
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Tidskriftsartikel (refereegranskat)abstract
- Serotonin (5-HT), an important modulator of both sensory and motor functions in the mammalian spinal cord, originates mainly in the raphe nuclei of the brainstem. However, following complete transection of the spinal cord, small amounts of 5-HT remain detectable below the lesion. It has been suggested, but not proven, that this residual 5-HT is produced by intraspinal 5-HT neurons. Here, we show by immunohistochemical techniques that cells containing the enzyme aromatic l-amino acid decarboxylase (AADC) occur not only near the central canal, as reported by others, but also in the intermediate zone and dorsal horn of the spinal gray matter. We show that, following complete transection of the rat spinal cord at S2 level, AADC cells distal to the lesion acquire the ability to produce 5-HT from its immediate precursor, 5-hydroxytryptophan. Our results indicate that this phenotypic change in spinal AADC cells is initiated by the loss of descending 5-HT projections due to spinal cord injury (SCI). By in vivo and in vitro electrophysiology, we show that 5-HT produced by AADC cells increases the excitability of spinal motoneurons. The phenotypic change in AADC cells appears to result from a loss of inhibition by descending 5-HT neurons and to be mediated by 5-HT1B receptors expressed by AADC cells. These findings indicate that AADC cells are a potential source of 5-HT at spinal levels below an SCI. The production of 5-HT by AADC cells, together with an upregulation of 5-HT2 receptors, offers a partial explanation of hyperreflexia below a chronic SCI.
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| 6. |
- Yang, Huanlei, et al.
(författare)
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Improving the bleachability of whole cotton stalk chemimechanical pulp with depectinization agents
- 2012
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Ingår i: BioResources. - 1930-2126. ; 7:3, s. 4171-4178
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Tidskriftsartikel (refereegranskat)abstract
- The effects of pretreatment agents on pectin removal and chemical compositions in cotton stalk bark were studied. The results showed that the reaction rates of the depectinization agents reacting with calcium pectinate were V-Na2C2O4 > V-Na5P3O10 > V-NaOH. The ratio of pectin removal reached 53.73% after pretreatment with 3% sodium oxalate. When the parameters of precondition were 3% sodium oxalate, 90 degrees C, and bleaching with 6.5% NaOH and 11% H2O2, the brightness of chemimechanical pulp from whole cotton stalk reached 76.18% ISO.
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