排序方式： 共有10条查询结果，搜索用时 15 毫秒
1
1.
Min JH Yang H Ivan M Gertler F Kaelin WG Pavletich NP 《Science (New York, N.Y.)》2002,296(5574):1886-1889
The ubiquitination of the hypoxia-inducible factor (HIF) by the von Hippel-Lindau tumor suppressor (pVHL) plays a central role in the cellular response to changes in oxygen availability. pVHL binds to HIF only when a conserved proline in HIF is hydroxylated, a modification that is oxygen-dependent. The 1.85 angstrom structure of a 20-residue HIF-1alpha peptide-pVHL-ElonginB-ElonginC complex shows that HIF-1alpha binds to pVHL in an extended beta strand-like conformation. The hydroxyproline inserts into a gap in the pVHL hydrophobic core, at a site that is a hotspot for tumorigenic mutations, with its 4-hydroxyl group recognized by buried serine and histidine residues. Although the beta sheet-like interactions contribute to the stability of the complex, the hydroxyproline contacts are central to the strict specificity characteristic of signaling. 相似文献
2.
Giovannoni SJ Tripp HJ Givan S Podar M Vergin KL Baptista D Bibbs L Eads J Richardson TH Noordewier M Rappé MS Short JM Carrington JC Mathur EJ 《Science (New York, N.Y.)》2005,309(5738):1242-1245
The SAR11 clade consists of very small, heterotrophic marine alpha-proteobacteria that are found throughout the oceans, where they account for about 25% of all microbial cells. Pelagibacter ubique, the first cultured member of this clade, has the smallest genome and encodes the smallest number of predicted open reading frames known for a free-living microorganism. In contrast to parasitic bacteria and archaea with small genomes, P. ubique has complete biosynthetic pathways for all 20 amino acids and all but a few cofactors. P. ubique has no pseudogenes, introns, transposons, extrachromosomal elements, or inteins; few paralogs; and the shortest intergenic spacers yet observed for any cell. 相似文献
3.
Mircea Constantin Sora Christoph von Horst Octavio Lpez-Albors Rafael Latorre 《Anatomia, histologia, embryologia》2019,48(6):564-571
With classical sheet plastination techniques such as E12, the level and thickness of the freeze‐cut sections decide on what is visible in the final sheet plastinated sections. However, there are other plastination techniques available where we can look for specific anatomical structures through the thickness of the tissue. These techniques include sectioning and grinding of plastinated tissue blocks or thick slices. The ultra‐thin E12 technique, unlike the classic E12 technique, starts with the plastination of a large tissue block. High temperatures (30–60°C) facilitate the vacuum‐forced impregnation by decreasing the viscosity of the E12 and increasing the vapour pressure of the intermediary solvent. By sectioning the cured tissue block with a diamond band saw plastinated sections with a thickness of <300 μm can be obtained. The thickness of plastinated sections can be further reduced by grinding. Resulting sections of <100 µm are suitable for histological staining and microscopic studies. Anatomical structures of interest in thick plastinate slices can be followed by variable manual grinding in a method referred to as Tissue Tracing Technique (TTT). In addition, the tissue thickness can be adapted to the transparency or darkness of tissue types in different regions of the same plastinated section. The aim of this study was to evaluate the advantages of techniques based on sectioning and grinding of plastinated tissue (E12 ultra‐thin and TTT) compared to conventional sheet‐forming techniques (E12). 相似文献
4.
Rafael Latorre Kees de Jong Mircea‐Constantin Sora Octavio Lpez‐Albors Carlos Baptista 《Anatomia, histologia, embryologia》2019,48(6):557-563
Epoxy plastination techniques were developed to obtain thin transparent body slices with high anatomical detail. This is facilitated because the plastinated tissue is transparent and the topography of the anatomical structures well preserved. For this reason, thin epoxy slices are currently used for research purposes in both macroscopic and microscopic studies. The protocol for the conventional epoxy technique (E12) follows the main steps of plastination—specimen preparation, dehydration, impregnation and curing/casting. Preparation begins with selection of the specimen, followed by freezing and slicing. Either fresh or fixed (embalmed) tissue is suitable for epoxy plastination, while slice thickness is kept between 1.5 and 3 mm. Impregnation mixture is made of epoxy E12 resin plus E1 hardener (100 ppw; 28 ppw). This mixture is reactive and temperature sensitive, and for this reason, total impregnation time under vacuum at room laboratory temperature should not last for more than 20–24 hr. Casting of impregnated slices is done in either flat chambers or by the so‐called sandwich method in either fresh mixture or the one used for impregnation. Curing is completed at 40°C to allow a complete polymerization of the epoxy‐mixture. After curing, slices can be photographed, scanned or used for anatomical study under screen negatoscope, magnification glass or fluorescent microscope. Based on epoxy sheet plastination, many anatomical papers have recent observations of and/or clarification of anatomical concepts in different areas of medical expertice. 相似文献
5.
综述了国内外生物质资源的超声波加工技术及其应用情况。描述了超声波提取的理论及国内超声波提取设备的相关情况。介绍了超声波用于精油、天然色素、多糖、总黄酮、生物碱、多酚、有机酸、油脂等成分提取的应用情况。同时介绍了超声波用于生物柴油的制备及生物质资源水解反应和材料改性等情况。 相似文献
6.
Mircea‐Constantin Sora Rafael Latorre Carlos Baptista Octavio Lpez-Albors 《Anatomia, histologia, embryologia》2019,48(6):526-531
Over the last four decades, plastination has been one of the best processes of preservation for organic tissue. In this process, water and lipids in biological tissues are replaced by polymers (silicone, epoxy, polyester) which are hardened, resulting in dry, odourless and durable specimens. Nowadays, after more than 40 years of its development, plastination is applied in more than 400 departments of anatomy, pathology, forensic sciences and biology all over the world. The most known polymers used in plastination are silicone (S10), epoxy (E12) and polyester (P40). The key element in plastination is the impregnation stage, and therefore depending on the polymer that is used, the optical quality of specimens differs. The S10 silicone technique is the most common technique used in plastination. Specimens can be used, especially in teaching, as they are easy to handle and display a realistic topography. Plastinated silicone specimens are used for displaying whole bodies, or body parts for exhibition. Transparent tissue sections, with a thickness between 1 and 4 mm, are usually produced by using epoxy (E12) or polyester (P40) polymer. These sections can be used to study both macroscopic and microscopic structures. Compared with the usual methods of dissection or corrosion, plastinated slices have the advantage of not destroying or altering the spatial relationships of structures. Plastination can be used as a teaching and research tool. Besides the teaching and scientific sector, plastination becomes a common resource for exhibitions, as worldwide more and more exhibitions use plastinated specimens. 相似文献
7.
Comparative metagenomics of microbial communities 总被引：1，自引：0，他引：1
Tringe SG von Mering C Kobayashi A Salamov AA Chen K Chang HW Podar M Short JM Mathur EJ Detter JC Bork P Hugenholtz P Rubin EM 《Science (New York, N.Y.)》2005,308(5721):554-557
The species complexity of microbial communities and challenges in culturing representative isolates make it difficult to obtain assembled genomes. Here we characterize and compare the metabolic capabilities of terrestrial and marine microbial communities using largely unassembled sequence data obtained by shotgun sequencing DNA isolated from the various environments. Quantitative gene content analysis reveals habitat-specific fingerprints that reflect known characteristics of the sampled environments. The identification of environment-specific genes through a gene-centric comparative analysis presents new opportunities for interpreting and diagnosing environments. 相似文献
8.
Christoph von Horst Rurik von Hagens Constantin‐Mircea Sora Robert W. Henry 《Anatomia, histologia, embryologia》2019,48(6):512-517
Plastination was a game‐changing invention for macroscopic anatomical preparation. The method yielded dry, odourless, tangible and durable specimens which allowed new exhibition and teaching set‐ups and paved the way for sophisticated preparations and spectacular positioning of specimens. Despite the impact of the new method, there have been similar techniques in place before. Exsiccation techniques, polymer embeddings and specimen impregnation with hardening substances were earlier methods which already included the main concepts that were later combined and refined in plastination. S10 silicone plastination, the technique most commonly known and applied, was followed by plastination methods suitable for research and sectional anatomy teaching. Numerous variations of sheet plastination techniques allow research applications and new ways of presenting topographic relations and mesoscopic insights. Besides the development of plastination techniques in sensu stricto, related techniques had a renaissance with new applications and developments, including corrosion casting and diaphonization methods. This brief review shall provide a historical context of plastination including some anecdotal spotlights on the ideas and innovations that lead to nowadays plastination techniques. 相似文献
9.
超声波技术在生物质资源加工领域的应用研究进展 总被引：7，自引：4，他引：7
综述了国内外生物质资源的超声波加工技术及其应用情况.描述了超声波提取的理论及国内超声波提取设备的相关情况.介绍了超声波用于精油、天然色素、多糖、总黄酮、生物碱、多酚、有机酸、油脂等成分提取的应用情况.同时介绍了超声波用于生物柴油的制备及生物质资源水解反应和材料改性等情况. 相似文献
10.
Antifungal activity of Aloe vera leaves 总被引：1，自引：0，他引：1
Aloe vera fresh leaves hydroalcoholic plant extract was tested against the mycelial growth of Botrytis gladiolorum, Fusarium oxysporum f.sp. gladioli, Heterosporium pruneti and Penicillium gladioli on Czapek-agar medium. The minimum fungicidal concentration (MFC) varied between 80 and 100 microl/ml, depending on the fungal species. 相似文献
1