Two class III chitin synthases specifically localized in appressoria and haustoria of Puccinia graminis f. sp. tritici

Rust fungi like Puccinia graminis f. sp. tritici are known to change their cell wall properties upon entering the plant tissue. Immunohistochemistry revealed the cellular localization of two class III chitin synthase isoforms in rust mycelia developing on and in the host plant. Isoform IIIa is restricted to fungal infection structures growing on the surface of the plant, such as germ tubes and, predominantly, appressoria. Isoform IIIb is found exclusively in haustoria developed inside the plant. Thus, the rust fungus uses at least two chitin synthase isoforms with specialized functions in the differentiation of infection structures during the biotrophic plant-pathogen-interaction.     

Hydrological structure and erosion damage caused by concentrated flow in cultivated catchments

This study analyses the between-catchment variability of rill volumes produced by concentrated flow erosion during winter in the northern part of the Paris Basin. The working hypotheses were that (i) runoff concentrates along channels determined by topography or by agricultural practices; (ii) rill length is a major component of rill volume variability on a catchment scale; (iii) rill cross-sectional areas are controlled by the size of upslope runoff-contributing areas connected to the corresponding channels. Two samples, one of 20 zero order catchments and the other of 15 catchments, were surveyed. For each catchment, the runoff collector network was modelled from topographical and agricultural information, and split into homogeneous segments. Each segment was characterized by its slope gradient (SL), the soil susceptibility to rill erosion (SSE) and the size of the upslope runoff-contributing areas (RCA) connected to it. These areas were identified by the structural state of their soil surface. The frequency of rill occurrence was highly correlated with RCA and SL. The rill cross-sectional areas of eroded channels were correlated with RCA, SL and SSE. Catchment erosion rates were estimated by adding together the predicted rill volumes for each segment within the catchment. These estimations were closely correlated with observed rill erosion rates. The relative spatial position of runoff collectors must be taken into account when examining the damage caused by concentrated flow erosion.     

UN ECE ICP Materials: Dose-Response Functions on Dry and Wet Acid Deposition Effects After 8 Years of Exposure

The main results of the International Co-operative Programme on Effects on Materials, including Historic and Cultural Monuments (ICP Materials) within the United Nations Economic Commission for Europe (UN ECE) are summarised. The 8-year field exposure programme involves 39 test sites in 12 European countries and in the United States and Canada. Dose-response functions (DRF) expressing the effect of dry and wet deposition as individual terms have been obtained for a wide range of materials including bronze, copper, weathering steel, zinc, aluminium, nickel, tin, stone materials, paint coatings and glass materials. The DRF's includes parameters that are easily available on different geographical scales and can be used for mapping areas of increased corrosion rates and for calculation of costs.     

Discrimination of recombinant and pituitary-derived bovine and porcine growth hormones by peptide mass mapping

Somatotropins, which are used in cattle for growth and lactating performances, are difficult to reliably detect because no direct method exists. Reversed-phase high-performance liquid chromatography (RP-HLC) coupled to electrospray ionization quadrupole mass spectrometry (ESI/MS) has been developed to separate and characterize the N-terminal peptides resulting from tryptic cleavage of natural and recombinant growth hormones from different species (bovine, porcine, and human) and suppliers. Conditions for tryptic digestion were optimized. This technique was found to be optimal to cleave efficiently the N-terminal peptide of the proteins without releasing too much noise from the matrix. Characterization of the peptides through ESI(+)-MS allowed natural and recombinant growth hormones from bovine and porcine species with N-terminal amino acid sequences differing from one amino acid residue to be discriminated. However, the studied human growth hormones had similar primary sequences that did not permit any discrimination between recombinant and natural forms, thus confirming the known identity of these hormones. Protein digestions with pepsin and chymotrypsin were also compared but were not conclusive due to the too small N-terminal peptides released after proteolysis.     

Supercritical carbon dioxide extraction and characterization of Laurus nobilis essential oil

Supercritical carbon dioxide extraction allowed essential oil of Laurus nobilis to be obtained. Extraction conditions were as follows: pressure, 90 bar; temperature, 50 degrees C; and carbon dioxide flow, Phi = 1.0 kg/h. Waxes were entrapped in the first separator set at 90 bar and -10 degrees C. The oil was recovered in the second separator working at 15 bar and 10 degrees C. The main components were 1,8-cineole (22.8%), linalool (12.5%), alpha-terpinyl acetate (11.4%), and methyleugenol (8.1%). Comparison with the hydrodistilled oil did not reveal any significant difference. Collection of samples at different extraction times during supercritical extraction allowed the change of the oil composition to be monitored. Lighter compounds such as hydrocarbon and oxygenated monoterpenes were extracted in shorter times than the heavier hydrocarbon and oxygenated sesquiterpenes.     

Photosynthesis and Leaf Area of Brachiaria brizantha in Response to Phosphorus and Zinc Nutrition

Phosphorus (P) and zinc (Zn) are important determinants of plant productivity, particularly in the tropical grasslands of Brazil. Nutrient deficiency is one of the most important factors limiting plant productivity, decreasing photosynthesis efficiency and plant development. The present study investigates in Brachiaria brizantha (Hochst. ex A. Rich.) Stapf. cv. ‘Marandu’: 1) the gas exchange measurements; 2) the total leaf area development; and 3) the dry matter production due to P and Zn nutrition. Plants of B. brizantha cv. ‘Marandu’ were grown in nutrient solution under five rates of P (0.1, 0.6, 1.1, 1.6, and 2.1 mmol L^?1) and five rates of Zn (0.00, 0.75, 1.5, 2.25, and 3.00 μmol L^?1), in a fractioned factorial. Plants were harvested two times. Phosphorus supply increased carbon dioxide (CO₂) assimilation and stomatal conductance, and decreased intercellular CO₂. The interaction P rates x Zn rates were significant for the total leaf area variables and shoot dry matter in the second growth period. The nutrition of P and Zn interfered in the B. brizantha productivity by changing the grass photosynthesis and leaf area.     

Cardiovascular and respiratory effects of ketamine infusions in isoflurane-anesthetized dogs before and during noxious stimulation

OBJECTIVE: To characterize the effects of ketamine administration on the cardiovascular and respiratory systems and on acid-base balance and to record adverse effects of ketamine in isoflurane-anesthetized dogs. ANIMALS: 6 healthy adult mongrel dogs. PROCEDURE: Dogs were anesthetized with isoflurane (1.25 times the individual minimum alveolar concentration) in oxygen, and ketamine was administered IV to target pseudo-steady-state plasma concentrations of 0, 0.5, 1, 2, 5, 8, and 11 microg/mL. Isoflurane concentration was reduced to an equipotent concentration. Cardiovascular, respiratory, and acid-base variables; body temperature; urine production; and adverse effects were recorded before and during noxious stimulation. Cardiac index, stroke index, rate-pressure product, systemic vascular resistance index, pulmonary vascular resistance index, left ventricular stroke work index, right ventricular stroke work index, arterial oxygen concentration, mixed-venous oxygen concentration, oxygen delivery, oxygen consumption, oxygen extraction ratio, alveolar-arterial oxygen partial pressure gradient, and venous admixture were calculated. Plasma ketamine and norketamine concentrations were measured. RESULTS: Overall, ketamine administration improved ventilation, oxygenation, hemodynamics, and oxygen delivery in isoflurane-anesthetized dogs in a dosedependent manner. With the addition of ketamine, core body temperature was maintained or increased and urine production was maintained at an acceptable amount. However, at the higher plasma ketamine concentrations, adverse effects such as spontaneous movement and profuse salivation were observed. Myoclonus and dysphoria were observed during recovery in most dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Infusion of ketamine appears to be a suitable technique for balanced anesthesia with isoflurane in dogs. Plasma ketamine concentrations between 2 to 3 microg/mL elicited the most benefits with minimal adverse effects.     

Populational dynamics of Stomoxys calcitrans (Linneaus) (Diptera: Muscidae) in three biocenosis, Minas Gerais, Brazil

Populational flux of the adult phase of Stomoxys calcitrans was observed in the municipal district of Pedro Leopoldo, Minas Gerais, Brazil. Three biocenoses were selected for the study: stable agrobiocenosis, pastural agrobiocenosis and eubiocenosis. The occurrence and the populational flux of the insects, using the Magoon trap for their capture, were established. For each trap located in different biocenoses, a crossbred calf (Bos taurus × Bos indicus) approximately 6-month-old was used as “live bait,” exposed weekly for 48 h in the traps. Of the three agrobiocenoses studied, the stable agrobiocenosis contributed the greatest number of specimens of. S. calcitrans captured, corresponding to 96.9% of the total flies of this species collected. S. calcitrans shows seasonal behavior for approximately 6 months (spring and summer being the rainiest months of the year). The population peaked during the months of November and December. During the months of July and August, there was no capture of flies.