Tundra plants protect the soil surface from UV     

Kevin A. Hughes  Kerstin Scherer  Petra Rettberg  Pete Convey 《Soil biology & biochemistry》2006,38(6):1488-1490

In the Arctic, seasonal ozone depletion is resulting in periods of enhanced UV-B radiation at ground level while regional climate change is associated with increasing temperatures. These changes are likely to alter plant distribution, biodiversity and morphology, which may have knock-on effects for microbially driven biogeochemical cycling and other soil processes. Our study examined the transmission of solar UV radiation through arctic tundra plants using a portable UV radiometer and the DLR-biofilm biological UV dosimeter. A strong negative correlation was found between vegetation cover and UV transmission to the soil surface. Penetration of UV to the soil beneath tundra plants varied depending upon plant morphology, being greater through low creeping plants than cushion plants, grasses or mosses. UV transmission to the soil surface beyond the foliage edge also varied with plant morphology and the presence of flowers.  相似文献   

Assessment of EST- and genomic microsatellite markers for variety discrimination and genetic diversity studies in wheat   总被引：22，自引：0，他引：22  

Fiona Leigh  Vince Lea  John Law  Petra Wolters  Wayne Powell  Paolo Donini 《Euphytica》2003,133(3):359-366

It is likely that in the near future sequence information from sequencing programmes and EST libraries will generate an abundance of genic microsatellite markers. This study is focused on the assessment of their likely impact and performance vis-à-vis their genomic counterparts. Microsatellites from two sources were used to assess the genetic diversity in 56 old and new varieties of bread wheat on the UK Recommended List. A set of 12 microsatellite markers generated from genomic libraries and 20 expressed sequence tag (EST)-derived microsatellites were used in the study, and the performance of both marker sets assessed. The EST-derived or genic microsatellites delivered fingerprints of superior quality, amplifying clear products with few stutter bands. Diversity levels as revealed bygenic microsatellites are similar to the few published results. The PIC values for the genic markers were generally lower than those calculated for the genomic microsatellites, though advantages of both marker classes for variety identification applications are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

A SNP map of the rat genome generated from cDNA sequences   总被引：1，自引：0，他引：1  

Zimdahl H  Nyakatura G  Brandt P  Schulz H  Hummel O  Fartmann B  Brett D  Droege M  Monti J  Lee YA  Sun Y  Zhao S  Winter EE  Ponting CP  Chen Y  Kasprzyk A  Birney E  Ganten D  Hubner N 《Science (New York, N.Y.)》2004,303(5659):807

  相似文献   

Canine renal pathology associated with grape or raisin ingestion: 10 cases.     

Carla M K Morrow  Victor E Valli  Petra A Volmer  Paul A Eubig 《Journal of veterinary diagnostic investigation》2005,17(3):223-231

Ten dogs suffered acute renal failure after ingesting > or = 3 g/kg (dry matter) of grapes or raisins. All dogs had degeneration or necrosis (or both) of proximal renal tubules with basement membranes remaining intact, and epithelial regeneration was observed in 5 out of 10 cases. Mineralized tubular debris or granular to proteinaceous casts (or both) were present in all cases. A golden-brown, globular, intracellular pigment of varying amounts and sizes was observed in 6 out of 10 cases with variable reaction with Prussian blue. Multifocal fibrinous arteritis of the large colon was seen in 2 out of 5 cases with globulin insudation of vessel wall demonstrated by immunohistochemical staining for immunoglobulin (Ig)G and IgM. Mineral analysis on frozen renal tissue from 2 out of 2 cases revealed mildly elevated Ca:P ratio in both. Clinically significant observations were preservation of the integrity of basement membranes after grape-induced tubular injury and presence of early epithelial regeneration. Thus, recovery may be possible if anuria is aggressively managed. With respect to potential pathophysiologic mechanisms, further research into the roles of calcium homeostasis, vascular reactivity, and the significance of the golden-brown pigment is indicated.  相似文献   

Suitability of SSCP-PCR analysis for molecular detection of quinolone resistance in Campylobacter jejuni     

Beckmann L  Müller M  Luber P  Schrader C  Bartelt E  Klein G 《Berliner und Münchener tier?rztliche Wochenschrift》2003,116(11-12):487-490

Foodborne infections with Campylobacter spp. are increasing, especially antibiotic resistant strains are emerging. Quinolone resistant isolates can cause failure of therapy in severe clinical infections. Molecular characterisation is needed for the detection of resistant variants of C. jejuni. Therefore 23 isolates from poultry and human medicine as well as three control strains were tested for their minimal inhibitory concentration, their Single-Strand-Conformation-Polymorphism (SSCP)-PCR pattern (a method for the detection of resistance determining point mutations), and their sequence of the quinolone resistance determining region (QRDR). Six different SSCP types could be identified: two types for quinolone resistant isolates and other types containing so called silent mutations without influence on the resistance. A genotypic monitoring of the quinolone resistance in C. jejuni can be useful for the early detection of new resistance variants. As a screening method for detection of point mutations in the QRDR the SSCP-PCR can be applied. Compared to other genotypic methods the SSCP-PCR is less time and cost consuming and needs only standard technical equipment.  相似文献   

Evaluation of the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication     

Väisänen M  Raekallio M  Kuusela E  Huttunen P  Leppäluoto J  Kirves P  Vainio O 《American journal of veterinary research》2002,63(7):969-975

OBJECTIVE: To compare the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication. ANIMALS: 42 client-owned dogs that underwent elective ovariohysterectomy. PROCEDURE: Each dog was randomly allocated to receive medetomidine and butorphanol tartrate (20 microgram/kg and 0.2 mg/kg, respectively, IM) or acepromazine maleate and butorphanol (0.05 and 0.2 mg/kg, respectively, IM) for preanesthetic medication. Approximately 80 minutes later, anesthesia was induced by administration of propofol and maintained by use of isoflurane in oxygen. Each dog was also given carprofen before surgery and buprenorphine after surgery. Plasma concentrations of epinephrine, norepinephrine, cortisol, and beta-endorphin were measured at various stages during the perioperative period. In addition, cardiovascular and clinical variables were monitored. RESULTS: Concentrations of epinephrine, norepinephrine, and cortisol were significantly lower for dogs administered medetomidine. Concentrations of beta-endorphin did not differ between the 2 groups. Heart rate was significantly lower and mean arterial blood pressure significantly higher in dogs administered medetomidine, compared with values for dogs administered acepromazine. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that for preanesthetic medications, medetomidine may offer some advantages over acepromazine with respect to the ability to decrease perioperative concentrations of stress-related hormones. In particular, the ability to provide stable plasma catecholamine concentrations may help to attenuate perioperative activation of the sympathetic nervous system.  相似文献   

Laser ablation-combustion-GC-IRMS--a new method for online analysis of intra-annual variation of delta13C in tree rings     

Schulze B  Wirth C  Linke P  Brand WA  Kuhlmann I  Horna V  Schulze ED 《Tree physiology》2004,24(11):1193-1201

We present a new, rapid method for high-resolution online determination of delta13C in tree rings, combining laser ablation (LA), combustion (C), gas chromatography (GC) and isotope ratio mass spectrometry (IRMS) (LA-C-GC-IRMS). Sample material was extracted every 6 min with a UV-laser from a tree core, leaving 40-microm-wide holes. Ablated wood dust was combusted to CO2 at 700 degrees C, separated from other gases on a GC column and injected into an isotope ratio mass spectrometer after removal of water vapor. The measurements were calibrated against an internal and an external standard. The tree core remained intact and could be used for subsequent dendrochronological and dendrochemical analyses. Cores from two Scots pine trees (Pinus sylvestris spp. sibirica Lebed.) from central Siberia were sampled. Inter- and intra-annual patterns of delta13C in whole-wood and lignin-extracted cores were indistinguishable apart from a constant offset, suggesting that lignin extraction is unnecessary for our method. Comparison with the conventional method (microtome slicing, elemental analysis and IRMS) indicated high accuracy of the LA-C-GC-IRMS measurements. Patterns of delta13C along three parallel ablation lines on the same core showed high congruence. A conservative estimate of the precision was +/- 0.24 per thousand. Isotopic patterns of the two Scots pine trees were broadly similar, indicating a signal related to the forest stand's climate history. The maximum variation in delta13C over 22 years was about 5 per thousand, ranging from -27 to -22.3 per thousand. The most obvious pattern was a sharp decline in delta13C during latewood formation and a rapid increase with spring early growth. We conclude that the LA-C-GC-IRMS method will be useful in elucidating short-term climate effects on the delta13C signal in tree rings.  相似文献   

Review: The role of antibodies,autoantigens and food allergens in canine atopic dermatitis          下载免费PDF全文

Cherie M. Pucheu‐Haston  Petra Bizikova  Melissa N. C. Eisenschenk  Domenico Santoro  Tim Nuttall  Rosanna Marsella 《Veterinary dermatology》2015,26(2):115-e30

  相似文献   

Review: Lymphocytes,cytokines, chemokines and the T‐helper 1–T‐helper 2 balance in canine atopic dermatitis          下载免费PDF全文

Cherie M. Pucheu‐Haston  Petra Bizikova  Rosanna Marsella  Domenico Santoro  Tim Nuttall  Melissa N. C. Eisenschenk 《Veterinary dermatology》2015,26(2):124-e32

  相似文献   

Use of activity monitors for assessment of pruritus in an acute model of canine atopic dermatitis     

Rachel Schwab‐Richards  Christine Prost  Jean Steffan  Wolfgang Seewald  Chiara Nenci  Petra Roosje 《Veterinary dermatology》2014,25(5):441-e69

  相似文献