An antigenic peptide produced by peptide splicing in the proteasome     

Vigneron N  Stroobant V  Chapiro J  Ooms A  Degiovanni G  Morel S  van der Bruggen P  Boon T  Van den Eynde BJ 《Science (New York, N.Y.)》2004,304(5670):587-590

CD8 T lymphocytes recognize peptides of 8 to 10 amino acids presented by class I molecules of the major histocompatibility complex. Here, CD8 T lymphocytes were found to recognize a nonameric peptide on melanoma cells that comprises two noncontiguous segments of melanocytic glycoprotein gp100(PMEL17). The production of this peptide involves the excision of four amino acids and splicing of the fragments. This process was reproduced in vitro by incubating a precursor peptide of 13 amino acids with highly purified proteasomes. Splicing appears to occur by transpeptidation involving an acyl-enzyme intermediate. Our results reveal an unanticipated aspect of the proteasome function of producing antigenic peptides.  相似文献   

An echocardiographic study of healthy Border Collies with normal reference ranges for the breed     

Jake H. Jacobson  June A. Boon  Janice M. Bright 《Journal of Veterinary Cardiology》2013,15(2):123-130

ObjectivesThe objectives of this study were to obtain standard echocardiographic measurements from healthy Border Collies and to compare these measurements to those previously reported for a general population of dogs.AnimalsStandard echocardiographic data were obtained from twenty apparently healthy Border Collie dogs. These data (n = 20) were compared to data obtained from a general population of healthy dogs (n = 69).MethodsBorder Collies were deemed healthy based on normal history, physical examination, complete blood count, serum biochemical profile, electrocardiogram, and blood pressure, with no evidence of congenital or acquired heart disease on echocardiographic examination. Standard two dimensional, M-mode, and Doppler echocardiographic measurements were obtained and normal ranges determined. The data were compared to data previously obtained at our hospital from a general population of normal dogs.ResultsTwo dimensional, M-mode, and Doppler reference ranges for healthy Border Collies are presented in tabular form. Comparison of the weight adjusted M-mode echocardiographic means from Border Collies to those from the general population of dogs showed Border Collies to have larger left ventricular systolic and diastolic dimensions, smaller interventricular septal thickness, and lower fractional shortening.ConclusionsThere are differences in some echocardiographic parameters between healthy Border Collies and the general dog population, and the echocardiographic reference ranges provided in this study should be used as breed specific reference values for Border Collies.  相似文献   

Suitability of granular carbon as an anode material for sediment microbial fuel cells     

Jan B. A. Arends  Evelyne Blondeel  Steve R. Tennison  Nico Boon  Willy Verstraete 《Journal of Soils and Sediments》2012,12(7):1197-1206

Purpose

Sediment microbial fuel cells (S-MFCs) are bio-electrochemical devices that are able to oxidize organic matter directly into harvestable electrical power. The flux of organic matter into the sediment is rather low; therefore, other researchers have introduced plants for a continuous supply of organic matter to the anode electrode. Until now only interconnected materials have been considered as anode materials in S-MFCs. Here, granular carbon materials were investigated for their suitability as an anode material in S-MFCs.

Materials and methods

Laboratory microcosms with eight different electrode materials (granules, felts and cloths) were examined with controlled organic matter addition under brackish conditions. Current density, organic matter removal and microbial community composition were monitored using 16S rRNA gene PCR followed by denaturing gradient gel electrophoresis (DGGE). The main parameters investigated were the influence of the amount of electrode material applied to the sediment, the size of the granular material and the electrode configuration.

Results and discussion

Felt material had an overall superior performance in terms of current density per amount of applied electrode material; felt and granular anode obtained similar current densities (approx. 50?C60?mA?m^?2), but felt materials required 29?% less material to be applied. Yet, when growing plants, granular carbon is more suited because it is considered to restore, upon disturbance, the electrical connectivity within the anode compartment. Small granules (0.25?C0.5?mm) gave the highest current density compared to larger granules (1?C5?mm) of the same material. Granules with a rough surface had a better performance compared to smooth granules of the same size. The different granular materials lead to a selection of distinct microbial communities for each material, as shown by DGGE.

Conclusions

Granular carbon is suitable as an anode material for S-MFCs. This opens the possibility for application of S-MFCs in cultivated areas. In a wider context, the application of granular carbon electrodes can also be an option for in situ bioremediation of contaminated soils.  相似文献   

Initial Carbon Storage in New Tephra Layers of Mt. Talang in Sumatra as Affected by Pioneer Plants     

Dian Fiantis  Malik Nelson  Jusop Shamshuddin  Tee Boon Goh  Eric Van Ranst 《Communications in Soil Science and Plant Analysis》2016,47(15):1792-1812

To date, no global data on carbon sequestration at the initial weathering phase of tephra deposits are available. To study carbon storage in the new volcanic deposit, tephra layers were reconstructed for a period of 46 months. The tephra samples were collected immediately after eruption of Mount (Mt.) Talang on 12 April 2005, over portions of the Solok District in West Sumatra, Indonesia. Pot experiments were filled with and without soil materials and covered with the collected tephra. The pot experiments were conducted in a wired house. The tephra was applied in 0, 2.5 and 5 cm depths to simulate natural tephra deposition. Every day 250 ml of filtered water was added and allowed to percolate. Solid fraction from the tephra layer was collected and analyzed at regular intervals and primary plant succession was observed over a period of 4 years. After 2 months, blue-green algae (cyanobacteria) started to colonize the bare surface tephra layer to form an algae mat. After 16 months, the surface was transformed into a green biofilm of lichen. Vascular plants (grasses and shrubs) started to be established after 2 years. Total carbon (TC) content of the tephra layer was increased significantly from 0.19 to 1.75% or eight times higher after 46 months of incubation. Higher TC storage was found in the 2.5 cm compared to that of the 5.0 cm tephra layer, which was reconstructed above the soil, with values of 1.75 and 0.89%, respectively. On the contrary, lesser amount of TC was accumulated in the single tephra layer (without soil underneath). Between 71 and 90% of TC was considered as total organic carbon (TOC). The labile organic carbon (LOC) content in the 2.5 cm and 5.0 cm of tephra layer was found to be 0.22 and 0.77%, respectively, at the end of incubation. This experiment confirmed the potential of tephra to capture carbon from the atmosphere with the help of nonvascular plants and then by vascular plants and finally sink them in the tephra layer.  相似文献   

Accountability of experts in the Danish national park process     

Dorthe H. Lund  Tove Enggrob Boon  Iben Nathan 《Forest Policy and Economics》2009,11(5-6):437-445

In 2002 the Danish Minister of Environment initiated a process to investigate the possibilities of establishing national parks in Denmark. For this purpose experts were mobilised to investigate the status and potentials of the areas in question.The national park process was extensive in scope and complex, and in theory such complexity is assumed to make it difficult for non-experts to understand all the relevant aspects of policy. This exclusion of non-experts may lead to scientification of politics. Furthermore politicisation of science might occur as experts might advocate political interests disguised as objective science, and policy-makers might select results that further their own interests. As a result policy-makers risk losing a source of legitimacy, scientists risk losing credibility and the citizens risk losing the possibility to hold policy-makers accountable for their decisions, which puts democracy at risk.This paper examines the accountability relationships that experts were a part of in the national park process. These include accountability towards the employer, towards the buyer and towards the general public. The purpose is to determine if these relationships were adequate to circumvent the problems associated with scientification of politics and to discuss how accountability relationships and thereby democracy could be strengthened.The empirical analysis shows that in the national park process experts were mainly accountable towards the National Forest and Nature Agency. There were formal accountability relationships between the experts and the local steering committees and the national advisory group, but these relationships were less significant. Moreover, despite the fact that the process was deemed unusually open to the public by the participants, the relationship between experts and the public cannot be characterised as an accountability relationship and could have been improved by including experts in the deliberative fora of the process.  相似文献   

Comparative cytotoxicity evaluation of lanthanide nanomaterials on mouse and human cell lines with metabolic and DNA-quantification assays     

Heng BC  Das GK  Zhao X  Ma LL  Tan TT  Ng KW  Loo JS 《Biointerphases》2010,5(3):FA88-FA97

Lanthanide nanomaterials are considered a less toxic alternative to quantum dots for bioimaging applications. This study evaluated the cytotoxicity of terbium (Tb)-doped gadolinium oxide (Gd(2)O(3)) and dysprosium oxide (Dy(2)O(3)) nanoparticles exposed to human (BEAS-2B) and mouse (L929) cell lines at a concentration range of 200-2000?μg/ml for 48 h. Two assay methods were utilized-WST-8 assay (colorimetric) based on mitochondrial metabolic activity and Pico-Green assay (fluorescence), which measures total DNA content. The authors' data showed that Tb-doped Gd(2)O(3) nanoparticles were consistently more toxic than Tb-doped Dy(2)O(3) nanoparticles. However, exposure to these nanomaterials caused a decrease in proliferation rate for both cell lines rather than a net loss of viable cells after 48 h of exposure. Additionally, there was some degree of discrepancy observed with the two assay methods. For the mouse L929 cell line, the WST-8 assay yielded consistently lower proliferation rates compared to the Pico-Green assay, whereas the opposite trend was observed for the human BEAS-2B cell line. This could arise because of the differential effects of these nanoparticles on the metabolism of L929 and BEAS-2B cells, which in turn may translate to differences in their postexposure proliferation rates. Hence, the Pico-Green assay could have an advantage over the WST-8 assay because it is not skewed by the differential effects of nanomaterials on cellular metabolism.  相似文献   

Coastal wetlands of Victoria,south‐eastern Australia: providing the inventory and condition information needed for their effective management and conservation          下载免费PDF全文

Paul I. Boon  Tim Allen  Geoff Carr  Doug Frood  Chris Harty  Andrew Mcmahon  Steve Mathews  Neville Rosengren  Steve Sinclair  Matt White  Jeff Yugovic 《水产资源保护:海洋与淡水生态系统》2015,25(4):454-479

Siberian sturgeon (Acipenser baerii) larvae fed Artemia nauplii enriched with poly‐β‐hydroxybutyrate (PHB): effect on growth performance,body composition,digestive enzymes,gut microbial community,gut histology and stress tests          下载免费PDF全文

Ebrahim Hossein Najdegerami  Kartik Baruah  Alireza Shiri  Anamaria Rekecki  Wim Van den Broeck  Patrick Sorgeloos  Nico Boon  Peter Bossier  Peter De Schryver 《Aquaculture Research》2015,46(4):801-812

The effects of feeding Artemia nauplii enriched with or without poly‐β‐hydroxybutyrate (PHB) and/or highly unsaturated fatty acids (HUFA) on Siberian sturgeon (Acipenser baerii) larvae were investigated. Feeding larvae with PHB‐enriched nauplii (PHB, PHB + HUFA) decreased the growth performance of the larvae. PHB affected the body composition by increasing the lipid content of the whole body and decreasing total saturated, monoenoic, n3, n6 and decosahexanoeic acid (DHA) in the larvae, indicating that the PHB addition affected lipid metabolism. A high activity of pepsin was observed in the digestive extracts of PHB treatments (PHB, PHB + HUFA), while PHB suppressed amylase activity in the intestine of the larvae. Based on molecular analysis, PHB changed the microbial community in the distal intestine of the larvae. The highest counts of goblet cells were observed in the HUFA‐containing treatments (HUFA, PHB + HUFA), indicating that HUFA addition may improve the mucosal barrier defence system. The overall quality of the larvae was evaluated by exposing them to different salinities and ammonia stress levels. PHB decreased survival rates in these challenges. Our results show that optimal PHB doses for bio‐encapsulation into Artemia remain to be determined for further application at the earliest larval stages of sturgeon.  相似文献   

Xylanases from microbial origin induce syrup formation in dough     

Peter De Schryver  Susana Seseña  Bert Decaigny  Tom Van de Wiele  Willy Verstraete  Nico Boon 《Journal of Cereal Science》2008

Syrup formation in refrigerated doughs is a problem since it reduces the doughs’ shelf life. Microbial exogenous xylanases associated with wheat kernels were found to play a role in this syruping phenomenon. Using xylanase-producing microorganisms isolated from wheat kernels, we investigated their potency to induce syruping in dough. Growth of the fungal xylanase producer Fusarium sp. (10² colony forming units (CFU)/g dough) and the bacterial xylanase producer Paenibacillus sp. (10⁴ CFU/g dough) in synthetic media and their respective addition to wheat dough could not bring about a significant amount of syruping. However, when these species were grown on moist wheat kernels and an extract of these kernels containing both the organisms and its xylanases was made and added to dough, intensive syruping was noted. This effect was primarily attributed to the xylanases present in the extract. These findings suggest that the involvement of xylanase-producing microorganisms in the syruping phenomenon is situated prior to harvest. Additional quantitative analyses of microbial biomass present on wheat kernels revealed that the fungi in particular could be correlated to higher microbial exogenous xylanase activities on wheat. Our results indicate that the syruping is linked to fungal xylanase production on the wheat kernels in the field.  相似文献   

Dissolved organic matter and its parent organic matter in grass upland soil horizons studied by analytical pyrolysis techniques   总被引：8，自引：0，他引：8  

Y. Huang  G. Eglinton  E. R. E. Van Der Hage  J. J. Boon  R. Bol  & P. Ineson 《European Journal of Soil Science》1998,49(1):1-15

We have sought to understand the molecular mechanisms by which dissolved organic matter (DOM) forms and soil organic matter (SOM) degrades in upland peaty gley soil under grass. Pyrolysis mass spectrometry (Py-MS) and pyrolysis gas chromatography mass spectrometry (Py-GC/MS) were applied to characterize the DOM collected from lysimeters and its parent SOM. The macromolecular organic matter in the litter and fermentation (Lf) horizon of the soil consists primarily of little decomposed lignocellulose from grass, whereas the humus (Oh) horizon is characterized by an accumulation of selectively decomposed lignocellulose material, microbial metabolites and bound fatty acids. The mineral horizon produced a relative enrichment of furan structures derived from microbial reworking of plant polysaccharides but virtually no lignin signals. A series of exceptional long chain C₄₃ to C₅₃ fatty acids with odd over even predominance, probably derived from mycobacteria, were also identified in the Oh horizon. Side-chain oxidation and shortening, increase of carboxyl functionality and selective removal of syringyl (S) > guaiacyl (G) > p-hydroxyphenyl (P) lignin units were the main reactions when lignin degraded. Compared with SOM, the DOM shows a large accumulation of more oxidized lignin and aromatic structures, especially those containing carboxylic and dicarboxylic acid functionalities and with shorter side-chain length. The polysaccharide-type compounds in the DOM were more modified (greater abundance of furan structures in pyrolysis products), and had significantly lower molecular weight and more diverse polymeric structures than did those in soils. Increased temperature and rainfall appeared to result in greater relative abundance of lignin degradation products and aromatic compounds in DOM.  相似文献