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51.
Christoffer Schander Am lie H. Scheltema Dimitry L. Ivanov 《Marine Biology Research》2006,2(5):303-315
During a cruise with R/V Oceanus out of Woods Hole organized by the National Science Foundation project WormNet, a new species of chaetodermomorph aplacophoran was found in the northwestern Atlantic on the continental rise, between 1100 and nearly 2900 m. An investigation into the material of older collections revealed that the species had previously been collected on numerous occasions but remained undescribed. We here describe the species under the name Falcidens halanychi sp. nov. The species is compared with F. limifossorides Salvini-Plawen 1992 that has the most similar overall morphology, but occurs in the eastern Pacific at lower slope and abyssal depths between 3700 and 4300 m. We illustrate the radula of limifossorides and the birefringent colours of the sclerites photographically for the first time. We also include two DNA barcodes of F. halanychi (cytochome oxidase I) to aid future molecular identification. 相似文献
52.
Gene expression programs in response to hypoxia: cell type specificity and prognostic significance in human cancers 总被引:1,自引:0,他引:1
53.
Dimitry A Chistiakov 《Journal of biomedical science》2010,17(1):92
Rapid repair of the denuded alveolar surface after injury is a key to survival. The respiratory tract contains several sources
of endogenous adult stem cells residing within the basal layer of the upper airways, within or near pulmonary neuroendocrine
cell rests, at the bronchoalveolar junction, and within the alveolar epithelial surface, which contribute to the repair of
the airway wall. Bone marrow-derived adult mesenchymal stem cells circulating in blood are also involved in tracheal regeneration.
However, an organism is frequently incapable of repairing serious damage and defects of the respiratory tract resulting from
acute trauma, lung cancers, and chronic pulmonary and airway diseases. Therefore, replacement of the tracheal tissue should
be urgently considered. The shortage of donor trachea remains a major obstacle in tracheal transplantation. However, implementation
of tissue engineering and stem cell therapy-based approaches helps to successfully solve this problem. To date, huge progress
has been achieved in tracheal bioengineering. Several sources of stem cells have been used for transplantation and airway
reconstitution in animal models with experimentally induced tracheal defects. Most tracheal tissue engineering approaches
use biodegradable three-dimensional scaffolds, which are important for neotracheal formation by promoting cell attachment,
cell redifferentiation, and production of the extracellular matrix. The advances in tracheal bioengineering recently resulted
in successful transplantation of the world's first bioengineered trachea. Current trends in tracheal transplantation include
the use of autologous cells, development of bioactive cell-free scaffolds capable of supporting activation and differentiation
of host stem cells on the site of injury, with a future perspective of using human native sites as micro-niche for potentiation
of the human body's site-specific response by sequential adding, boosting, permissive, and recruitment impulses. 相似文献
54.
55.
Alexander Poser Regina Lohmayer Carsten Vogt Kay Knoeller Britta Planer-Friedrich Dimitry Sorokin Hans-H. Richnow Kai Finster 《Extremophiles : life under extreme conditions》2013,17(6):1003-1012
Microbial disproportionation of elemental sulfur to sulfide and sulfate is a poorly characterized part of the anoxic sulfur cycle. So far, only a few bacterial strains have been described that can couple this reaction to cell growth. Continuous removal of the produced sulfide, for instance by oxidation and/or precipitation with metal ions such as iron, is essential to keep the reaction exergonic. Hitherto, the process has exclusively been reported for neutrophilic anaerobic bacteria. Here, we report for the first time disproportionation of elemental sulfur by three pure cultures of haloalkaliphilic bacteria isolated from soda lakes: the Deltaproteobacteria Desulfurivibrio alkaliphilus and Desulfurivibrio sp. AMeS2, and a member of the Clostridia, Dethiobacter alkaliphilus. All cultures grew in saline media at pH 10 by sulfur disproportionation in the absence of metals as sulfide scavengers. Our data indicate that polysulfides are the dominant sulfur species under highly alkaline conditions and that they might be disproportionated. Furthermore, we report the first organism (Dt. alkaliphilus) from the class Clostridia that is able to grow by sulfur disproportionation. 相似文献
56.
John Couwenberg Annett Thiele Franziska Tanneberger J��rgen Augustin Susanne B?risch Dimitry Dubovik Nadzeya Liashchynskaya Dierk Michaelis Merten Minke Arkadi Skuratovich Hans Joosten 《Hydrobiologia》2011,674(1):67-89
Drained peatlands in temperate Europe are a globally important source of greenhouse gas (GHG) emissions. This article outlines a methodology to assess emissions and emission reductions from peatland rewetting projects using vegetation as a proxy. Vegetation seems well qualified for indicating GHG fluxes from peat soils as it reflects long-term water level, affects GHG emissions via assimilate supply and aerenchyma and allows fine-scaled mapping. The methodology includes mapping of vegetation types characterised by the presence and absence of species groups indicative for specific water level classes. GHG flux values are assigned to the vegetation types following a standardized protocol and using published emission values from plots with similar vegetation and water level in regions with similar climate and flora. Carbon sequestration in trees is accounted for by estimating the annual sequestration in tree biomass from forest inventory data. The method follows the criteria of the Voluntary Carbon Standard and is illustrated using the example of two Belarusian peatlands. 相似文献
57.
Sediments from six soda lakes of the Kulunda Steppe (Altai, Russia) and from hypersaline alkaline lakes of Wadi Natrun (Egypt) were analyzed for the presence of cbb and aclB genes encoding key enzymes Ci assimilation (RuBisCO in Calvin-Benson and ATP citrate lyase in rTCA cycles, respectively). The cbbL gene (RuBisCO form I) was found in all samples and was most diverse, while the cbbM (RuBisCO form II) and aclB were detected only in few samples and with a much lower diversity. The cbbL libraries from hypersaline lakes were dominated by members of the extremely haloalkaliphilic sulfur-oxidizing Ectothiorhodospiraceae, i.e. the chemolithotrophic Thioalkalivibrio and the phototrophic Halorhodospira. In the less saline soda lakes from the Kulunda Steppe, the cbbL gene comprised up to ten phylotypes with a domination of members of a novel phototrophic Chromatiales lineage. The cbbM clone libraries consisted of two major unidentified lineages probably belonging to chemotrophic sulfur-oxidizing Gammaproteobacteria. One of them, dominating in the haloalkaline lakes from Wadi Natrun, was related to a cbbM phylotype detected previously in a hypersaline lake with a neutral pH, and another, dominating in lakes from the Kulunda Steppe, was only distantly related to the Thiomicrospira cluster. The aclB sequences detected in two samples from the Kulunda Steppe formed a single, deep branch in the Epsilonproteobacteria, distantly related to Arcobacter sulfidicus. 相似文献
58.
Elfaridah P. FrazierJeff S. Isenberg Sruti ShivaLei Zhao Paul SchlesingerJulie Dimitry Mones S. Abu-AsabMaria Tsokos David D. RobertsWilliam A. Frazier 《Matrix biology》2011,30(2):154-161
CD47, a receptor for thrombospondin-1, limits two important regulatory axes: nitric oxide-cGMP signaling and cAMP signaling, both of which can promote mitochondrial biogenesis. Electron microscopy revealed increased mitochondrial densities in skeletal muscle from both CD47 null and thrombospondin-1 null mice. We further assessed the mitochondria status of CD47-null vs WT mice. Quantitative RT-PCR of RNA extracted from tissues of 3 month old mice revealed dramatically elevated expression of mRNAs encoding mitochondrial proteins and PGC-1α in both fast and slow-twitch skeletal muscle from CD47-null mice, but modest to no elevation in other tissues. These observations were confirmed by Western blotting of mitochondrial proteins. Relative amounts of electron transport enzymes and ATP/O2 ratios of isolated mitochondria were not different between mitochondria from CD47-null and WT cells. Young CD47-null mice displayed enhanced treadmill endurance relative to WTs and CD47-null gastrocnemius had undergone fiber type switching to a slow-twitch pattern of myoglobin and myosin heavy chain expression. In 12 month old mice, both skeletal muscle mitochondrial volume density and endurance had decreased to wild type levels. Expression of myosin heavy chain isoforms and myoglobin also reverted to a fast twitch pattern in gastrocnemius. Both CD47 and TSP1 null mice are leaner than WTs, use less oxygen and produce less heat than WT mice. CD47-null cells produce substantially less reactive oxygen species than WT cells. These data indicate that loss of signaling from the TSP1-CD47 system promotes accumulation of normally functioning mitochondria in a tissue-specific and age-dependent fashion leading to enhanced physical performance, lower reactive oxygen species production and more efficient metabolism. 相似文献
59.
60.
Dimitry A.Chistiakov Lyudmila M.Kuzenkova Kirill V.Savost’anov Anait K.Gevorkyan Alexander A.Pushkov Alexey G.Nikitin Nato D.Vashakmadze Natalia V.Zhurkova Tatiana V.Podkletnova Leila S.Namazova-Baranova Alexander A.Baranove 《遗传学报》2014,41(4):197-203
Mucopolysaccharidosis type II (MPS II) is a rare X-linked disorder caused by alterations in the iduronate-2-sulfatase (IDS) gene. In this study, IDS activity in peripheral mononuclear blood monocytes (PMBCs) was measured with a fluorimetric enzyme assay. Urinary glycosaminoglycans (GAGs) were quantified using a colorimetric assay. All IDS exons and intronic flanks were bidirectionally sequenced. A total of 15 mutations (all exonic region) were found in 17 MPS II patients. In this cohort of MPS II patients, all alterations in the IDS gene were caused by point nucleotide substitutions or small deletions. Mutations p.Arg88His and p.Arg172* occurred twice. All mu- tations were inherited except for p.Gly489Alafs*7, a germline mutation. We found four new mutations (p.Ser142Phe, p.Arg233Gly, p.Glu430*, and p.Ile360Tyrfs*31). In Epstein-Barr virus (EBV)-immortalized PMBCs derived from the MPS II patients, no IDS protein was detected in case of the p.Ser142Phe and p.Ile360Tyrfs*31 mutants. For p.Arg233Gly and p.Glu430*, we observed a residual expression of IDS. The p.Arg233Gly and p.Glu430* mutants had a residuary enzymatic activity that was lowered by 14.3 and 76-fold, respectively, compared with healthy controls. This observation may help explain the mild disease phenotype in MPS II patients who had these two mutations whereas the p.Ser142Phe and p.Ile360Tyrfs*31 mutations caused the severe disease manifestation. 相似文献