Centimetre-scale digital representations of terrain and impacts on depression storage and runoff

The microscale topography of a 20 × 10 m hillslope in a burned portion of Kootenay National Park, British Columbia, Canada was determined through laser scanning at a sub-centimetre scale. Digital terrain models (DTM) were developed for this hillslope at the 0.75 cm, 10 cm, 25 cm, 50 cm, 75 cm and 1 m scales. Random Roughness, Tortuosity and Mean Upslope Depression were computed for bare and vegetated surfaces created at each resolution to determine mean depression storage as a function of resolution. Results for these various roughness parameters and associated depression storage values are not found to change appreciably between the vegetated and bare surface DTMs, and moreover do not change notably with increasing grid cell resolution. Depression storage was also computed using a GIS-based method, the values of which are considered to be, at the highest resolution of 0.75 cm, the most realistic for comparative purposes. Mean depression storage using this latter approach decreases significantly with an increase in grid cell size, in contrast to the values based on Random Roughness which remain stable with increasing grid cell size. The generation of Hortonian overland flow was modelled at different scales using the GIS-derived DTMs. The values of depression storage for the various scales of DTM are demonstrated to have significant influences on overland flow generation. The scale of the DTM affects the changes over time between the proportion of water going into depression storage and that contributing to overland flow, with more water being retained as depression storage at a particular value of rainfall excess after infiltration for the smaller DTM scalings. When overland flow develops from a rising groundwater table in a simulation exercise, water depths are initially lower than the primary roughness elements on the land surface and water is relatively disconnected. As water depths increase, more integrated connections form.     

New Bruce-ladder multiplex PCR assay for the biovar typing of Brucella suis and the discrimination of Brucella suis and Brucella canis

Rapid and specific identification of Brucella suis at the biovar level is necessary because some of the biovars that infect animals are pathogenic for humans. None of the molecular typing methods described so far are able to discriminate B. suis biovars in a single test and differentiation of B. suis from Brucella canis by molecular approaches can be difficult. This article describes a new multiplex PCR assay, Suis-ladder, for fast and accurate identification of B. suis at the biovar level and the differentiation of B. suis, B. canis and Brucella microti. An advancement of the original Bruce-ladder PCR protocol which allows the correct discrimination of all known Brucella species is also described.     

Annual survival probabilities of juvenile loggerhead sea turtles indicate high anthropogenic impact on Mediterranean populations

相似文献   

Definition and clinical evaluation of a recruiting airway pressure based on the specific lung elastance in anesthetized dogs

ObjectiveTo determine the specific lung elastance (SE_L) in anesthetized dogs and to evaluate the efficacy of a SE_L-based recruiting airway pressure (RP_aw) at improving global and regional lung aeration.Study designRetrospective and prospective clinical study.AnimalsA total of 28 adult dogs were included in the retrospective study and six adult dogs in the prospective study.MethodsRetrospective study: SE_L and SE_L-based RP_aw were determined using previously published data. In mechanically ventilated dogs undergoing thoracic computed tomography (CT), SE_L was calculated as ΔP_L/(V_T/EELV), where ΔP_L is the driving transpulmonary pressure, V_T is the tidal volume and EELV is the end-expiratory lung volume. The ratio of lung to respiratory system elastance (E_L/E_rs) was determined. SE_L and E_L/E_rs were used to calculate the SE_L-based RP_aw. Prospective study: dogs underwent thoracic CT at end-expiration and at end-inspiration using the SE_L-based RP_aw, and global and regional aeration was determined. For analysis of regional aeration, lungs were divided into cranial, intermediate and caudal regions. Regional compliance was also calculated. A p value <0.05 was considered significant.ResultsThe SE_L and E_L/E_rs were 12.7 ± 3.1 cmH₂O and 0.54 ± 0.07, respectively. The SE_L-based RP_aw was 29.1 ± 7.6 cmH₂O. In the prospective study, the RP_aw was 28.2 ± 1.3 cmH₂O. During RP_aw, hyperinflation increased (p = 0.0003) whereas poorly aerated (p < 0.0001) and nonaerated (p = 0.01) tissue decreased. Normally aerated tissue did not change (p = 0.265). Regional compliance was higher in the intermediate (p = 0.0003) and caudal (p = 0.034) regions compared with the cranial region. Aeration did not differ between regions (p > 0.05).Conclusions and clinical relevanceAn SE_L-based RP_aw reduces poorly and nonaerated lung tissue in anesthetized dogs. In nonsurgical anesthetized dogs, an RP_aw near 30 cmH₂O is effective at improving lung aeration.     

Genetic analysis and molecular characterisation of laboratory and field mutants of Botryotinia fuckeliana (Botrytis cinerea) resistant to QoI fungicides

BACKGROUND: QoI fungicides, inhibitors of mitochondrial respiration, are considered to be at high risk of resistance development. In several phytopathogenic fungi, resistance is caused by mutations (most frequently G143A) in the mitochondrial cytochrome b (cytb) gene. The genetic and molecular basis of QoI resistance were investigated in laboratory and field mutants of Botryotinia fuckeliana (de Bary) Whetz. exhibiting in vitro reduced sensitivity to trifloxystrobin. RESULTS: B. fuckeliana mutants highly resistant to trifloxystrobin were obtained in the laboratory by spontaneous mutations in wild‐type strains, or from naturally infected plants on a medium amended with 1–3 mg L^?1 trifloxystrobin and 2 mM salicylhydroxamic acid, an inhibitor of alternative oxidase. No point mutations were detected, either in the complete nucleotide sequences of the cytb gene or in those of the aox and Rieske protein genes of laboratory mutants, whereas all field mutants carried the G143A mutation in the mitochondrial cytb gene. QoI resistance was always maternally inherited in ascospore progeny of sexual crosses of field mutants with sensitive reference strains. CONCLUSIONS: The G143A mutation in cytb gene is confirmed to be responsible for field resistance to QoIs in B. fuckeliana. Maternal inheritance of resistance to QoIs in progeny of sexual crosses confirmed that it is caused by extranuclear genetic determinants. In laboratory mutants the heteroplasmic state of mutated mitochondria could likely hamper the G143A detection, otherwise other gene(s) underlying different mechanisms of resistance could be involved. Copyright © 2012 Society of Chemical Industry     

Selection,characterization and genetic analysis of laboratory mutants of <Emphasis Type="Italic">Botryotinia fuckeliana</Emphasis> (<Emphasis Type="Italic">Botrytis cinerea</Emphasis>) resistant to the fungicide boscalid

Resistance to the fungicide boscalid in laboratory mutants of Botryotinia fuckeliana (Botrytis cinerea) was investigated. The baseline sensitivity to boscalid was evaluated in terms of colony growth (EC₅₀ = 0.3–3 μg ml⁻¹; MIC = 10–30 μg ml⁻¹) and conidial germination (EC₅₀ = 0.03–0.1 μg ml⁻¹; MIC = 1–3 μg ml⁻¹) tests. Mutants were selected in vitro from wild-type strains of the fungus on a fungicide-amended medium containing acetate as a carbon source. Mutants showed two different levels of resistance to boscalid, distinguishable through the conidial germination tests: low (EC₅₀ ∼ 0.3 μg ml⁻¹, ranging from 0.03 to 1 μg ml⁻¹; MIC > 100 μg ml⁻¹) and high (EC₅₀ > 100 μg ml⁻¹) resistance. Analysis of meiotic progeny from crosses between resistant mutants and sensitive reference strains showed that resistant phenotypes were due to mutations in single major gene(s) inherited in a Mendelian fashion, and linked with both the Daf1 and Mbc1 genes, responsible for resistance to dicarboximide and benzimidazole fungicides, respectively. Gene sequence analysis of the four sub-units of the boscalid-target protein, the succinate dehydrogenase enzyme, revealed that single or double point mutations in the highly conserved regions of the iron-sulphur protein (Ip) gene were associated with resistance. Mutations resulted in proline to leucine or phenylalanine replacements at position 225 (P225L or P225F) in high resistant mutants, and in a histidine to tyrosine replacement at position 272 (H272Y) in low resistant mutants. Sequences of the flavoprotein and the two transmembrane sub-units of succinate dehydrogenase were never affected.     

Volatile Organic Compounds,Indole, and Biogenic Amines Assessment in Two Mediterranean Irciniidae (Porifera,Demospongiae)

Solid phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was employed for the headspace determination of the volatile organic fraction emitted by two of the most common Mediterranean demosponges, Ircinia variabilis and Sarcotragus spinosulus, and of indole and some biogenic amines released by sponges in an aqueous medium. A total of 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane and 75 µm carboxen/polydimethylsiloxane fibers were used for the headspace extraction of low molecular weight sulfur compounds from a hermetically sealed vial containing sponge fragments, while the direct immersion determination of indole and biogenic amines was performed. The biogenic amines were extracted after in-solution derivatization with isobutyl chloroformate. All analytical parameters (linearity, limits of detection, and quantification, precision, and recovery) were evaluated for indole and biogenic amines. SPME-GC-MS proved to be a reliable means of highlighting the differences between molecules released by different sponges, principally responsible for their smell. The combined approaches allowed the identification of several volatile compounds in the headspace and other molecules released by the sponges in an aqueous medium, including indole and the BAs cadaverine, histamine, isobutylamine, isopentylamine, propylamine, 2-phenylethylamine, putrescine and tryptamine. The results obtained represent a further contribution to the picture of odoriferous molecules secreted by sponges.     

CATASAN Is a New Anti-Biofilm Agent Produced by the Marine Antarctic Bacterium Psychrobacter sp. TAE2020

The development of new approaches to prevent microbial surface adhesion and biofilm formation is an emerging need following the growing understanding of the impact of biofilm-related infections on human health. Staphylococcus epidermidis, with its ability to form biofilm and colonize biomaterials, represents the most frequent causative agent involved in infections of medical devices. In the research of new anti-biofilm agents against S. epidermidis biofilm, Antarctic marine bacteria represent an untapped reservoir of biodiversity. In the present study, the attention was focused on Psychrobacter sp. TAE2020, an Antarctic marine bacterium that produces molecules able to impair the initial attachment of S. epidermidis strains to the polystyrene surface. The setup of suitable purification protocols allowed the identification by NMR spectroscopy and LC-MS/MS analysis of a protein–polysaccharide complex named CATASAN. This complex proved to be a very effective anti-biofilm agent. Indeed, it not only interferes with cell surface attachment, but also prevents biofilm formation and affects the mature biofilm matrix structure of S. epidermidis. Moreover, CATASAN is endowed with a good emulsification activity in a wide range of pH and temperature. Therefore, its use can be easily extended to different biotechnological applications.