Lack of sensitization to the effects of d-amphetamine and apomorphine on sensorimotor gating in rats

Haemolytic-uremic syndrome (HUS) is the leading cause of acute renal failure in the childhood. It is characterised by microangiopathic hemolytic anemia, thrombocytopenia, acute renal failure and injury of the renal microvascular endothelium. In HUS the condition of proteolytic kallikrein-kinin system is unknown. The renal KKS seems to participate in the regulation of blood pressure, control of sodium and water excretion, renal vascular resistance and renin release. In this study the role kallikrein in the developing HUS was studied. The general activity of kallikrein in plasma and urine was determined by trypsin-like peptidohydrolase activity (TP), which was measured using substrate Z-D-Ala-Leu-Arg-pNa. Chymotrypsin-like protease activity (ChP) was measured using substrate Glp-Ala-Ala-Leu-pNa. Clinical data were analysed on 60 pediatric patients with HUS, 29 girls and 31 boys, ranging in the age from 3 months to 11 years. TP and ChP levels were determined in different periods of HUS (anuria, diuresis beginning, polyuria, recovery) in serum and urine. In acute phase TP and ChP activities increased significantly. In diuresis recovery serum TP activity was higher, but urine TP level became normal. In dynamic serum and urine ChP levels had tendency to decrease. The present work showed that TP and ChP levels demonstrated activity of pathological renal process and condition of glomerules.     

Effect of thermal treatment on the growth,structure and luminescence of nitride-passivated silicon nanoclusters

Silicon nanoclusters (Si-ncs) embedded in silicon nitride films have been studied to determine the effects that deposition and processing parameters have on their growth, luminescent properties, and electronic structure. Luminescence was observed from Si-ncs formed in silicon-rich silicon nitride films with a broad range of compositions and grown using three different types of chemical vapour deposition systems. Photoluminescence (PL) experiments revealed broad, tunable emissions with peaks ranging from the near-infrared across the full visible spectrum. The emission energy was highly dependent on the film composition and changed only slightly with annealing temperature and time, which primarily affected the emission intensity. The PL spectra from films annealed for duration of times ranging from 2 s to 2 h at 600 and 800°C indicated a fast initial formation and growth of nanoclusters in the first few seconds of annealing followed by a slow, but steady growth as annealing time was further increased. X-ray absorption near edge structure at the Si K- and L_3,2-edges exhibited composition-dependent phase separation and structural re-ordering of the Si-ncs and silicon nitride host matrix under different post-deposition annealing conditions and generally supported the trends observed in the PL spectra.     

Homology modelling of two subtilisin-like proteases from the hyperthermophilic archaea Pyrococcus furiosus and Thermococcus stetteri

The hyperthermophilic archaeon Pyrococcus furiosus produces an extracellular, glycosylated hyperthermostable subtilisin-like serine protease, termed pyrolysin (Voorhorst,W.G.B., Eggen,R.I.L., Geerling,A.C.M., Platteeuw,C., Siezen,R.J. and de Vos,W.M. (1996) J. Biol. Chem., 271, 20426-20431). Based on the pyrolysin coding sequence, a pyrolysin-like gene fragment was cloned and characterized from the extreme thermophilic archaeon Thermococcus stetteri. Like pyrolysin, the deduced sequence of this serine protease, designated stetterlysin, contains a catalytic domain with high homology with other subtilases, allowing homology modelling starting from known crystal structures. Comparison of the predicted three-dimensional models of the catalytic domain of stetterlysin and pyrolysin with the crystal structure of subtilases from mesophilic and thermophilic origin, i.e. subtilisin BPN' and thermitase, and the homology model of subtilisin S41 from psychrophilic origin, led to the identification of features that could be related to protein stabilization. Higher thermostability was found to be correlated with an increased number of residues involved in pairs and networks of charge-charge and aromatic-aromatic interactions. These highly thermostable proteases have several extra surface loops and inserts with a relatively high frequency of aromatic residues and Asn residues. The latter are often present in putative N-glycosylation sites. Results from modelling of known substrates in the substrate- binding region support the broad substrate range and the autocatalytic activation previously suggested for pyrolysin.      

Field Evaluation of Plant Odor and Pheromonal Combinations for Attracting Plum Curculios

The attractiveness of different synthetic host odors and a synthetic aggregation pheromone (grandisoic acid [GA]) to overwintered adult plum curculios (PCs), Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), was examined using two types of traps (sticky panels and black pyramids) placed in border areas surrounding an unsprayed section of an apple orchard in Massachusetts. In 2001, we evaluated the response of PCs to three synthetic fruit volatiles (benzaldehyde [BEN], ethyl isovalerate [EIV], and limonene [LIM]) assessed alone and in combination with GA, as well as the response to GA alone and a no-odor (control) treatment. BEN was the only host volatile that synergized the response of PCs to GA for both trap types. For both trap types, GA was as attractive to PCs as a single component as when in combination with either EIV or LIM. In 2002, four release rates of BEN (0, 2.5, 10, and 40 mg/day) and two release rates of GA (1 and 2 mg/day) were evaluated for attractiveness to PCs using panel and pyramid traps. For panel traps, an increase in amount of GA released (from 1 to 2 mg/day) was associated with a 35% increase in captures. However, PC captures by pyramid traps were similar regardless of the amount of GA released. For panel traps, 10 and 40 mg/day of BEN were the most attractive release rates regardless of the amount of GA released. For pyramid traps baited with GA. PC captures were enhanced by the presence of BEN, regardless of release rate. In 2003, GA at 1 mg/day + BEN at 80 mg/day of release did not enhance PC captures by panel traps relative to lower release rates of BEN. Pyramid traps releasing GA at 1 mg/day performed best when baited with BEN at 10 mg/day of release; a release rate of 80 mg/day of BEN decreased the attractiveness of the binary combination of BEN + GA. Combined results suggest that BEN at 10 mg/day + GA at 1 mg/day of release constitutes an attractive lure that may improve the effectiveness of monitoring traps for PCs.     

The current and residual value of superphosphate,Christmas Island C-grade ore,and Calciphos as fertilizers for a subterranean clover pasture

The effectiveness in the year of application of three phosphorus fertilizers, superphosphate, Christmas Island C-grade ore, and 500°C calcined Christmas Island C-grade ore (Calciphos), was measured for 5 consecutive years in a field experiment on a lateritic soil. The residual value of the phosphorus fertilizers was also measured for 6 years. Dry matter production of subterranean clover-based pasture and bicarbonate extractable soil phosphorus were used as indicators of fertilizer effectiveness.Despite the use of very large amounts of C-grade ore and Calciphos, the plateau of the pasture yield versus fertilizer applied curve for these fertilizers did not reach the yield plateau achieved with superphosphate in either the short or long term.C-grade ore and Calciphos were 3% and 8% as effective as superphosphate for dry matter production in the year of application. Relative to superphosphate applied in the current year the effectiveness of superphosphate decreased by about 70% between the first and second year after application and decreased by a further 14% from year 3 to year 6. C-grade ore and Calciphos remained about 2% and 9% as effective as currently applied superphosphate each year.The residual value of superphosphate as measured by bicarbonate-extracted soil phosphorus decreased by about 60% from year 2 to year 7. The residual value of Calciphos was very low for year 2, doubled from year 2–4 and thereafter decreased gradually to its original value by year 7. The residual value of C-grade ore was extremely low throughout the experiment. Thus after year 2, compared to pasture yield, bicarbonate extracted soil phosphorus overestimated the residual value of superphosphate and calciphos.It follows that neither C-grade ore or Calciphos are suitable replacement fertilizers for superphosphate for use on pastures growing on lateritic soils in south-western Australia.     

The effect of short-range host odor stimuli on host fruit finding and feeding behavior of plum curculio adults (Coleoptera: Curculionidae)

In laboratory assays, we investigated responses of female plum curculios (PCs),Conotrachelus nenuphar (Herbst), to host and nonhost fruit or leaf odor when PCs were crawling on experimental tree branchlets or twigs. In choice tests where test specimens were hung from the ends of a wooden crosspiece, PCs made significantly more visits to host plum fruit than to plum leaves, nonhost tomato fruit, wax models of plum fruit, or blanks (wire). In similar tests, PCs made significantly more visits to plum leaves compared to nonhost maple leaves or to blanks. PCs in test chambers that contained host or nonhost odor were significantly more prone to feed on wax plum models in the presence of odor from host fruit or host leaves compared to odor from nonhost fruit or leaves or a water blank. In choice tests offering alternating cluster types on an apple branchlet, PCs visited leaf clusters bearing a host apple fruit more than leaf clusters without a fruit. In tests to assay the distance at which PCs can detect an individual host fruit, PCs crawled from the central stem of an apple branchlet onto a side stem significantly more often when an apple fruit on a side stem was hung 2 cm from the central stem compared to 4 or 8 cm away. Our combined results suggest that PCs use host fruit odor to locate host fruit at close range.     

Host odor and visual stimulus interaction during intratree host finding behavior ofRhagoletis pomonella flies

Responses ofRhagoletis pomonella (Walsh) (Diptera: Tephritidae) flies to host fruit visual stimuli (apples or models of apples) and chemical stimuli (synthetic apple volatile blend) were studied in semidwarf field-caged apple trees. Three different fruit or model densities (1, 4, or 16 fruit or models/ tree) and two odor release rates [ca. 0.7g/hr (close to the natural release rate of a ripe apple) and ca. 500g/hr (amount of odor released by commercially sold apple maggot traps)] were tested. Individually released flies were followed as they moved within a tree for a maximum of 20 min. We recorded three-dimensional search paths followed by foraging flies and computed such variables as total relative distance traveled before alighting on a fruit or model, track length between individual alightment sites, and directness of flight to fruits or models. Effect of odor on propensity to alight on fruit or models and host-searching behavior prior to alighting on fruit or on models varied according to fruit or model color and density. If the fruit visual stimulus was strong (e.g., red color), odor did not increase the probability of finding fruit or fruit models. As the visual stimulus became progressively weaker (red to green to clear), odor (irrespective of concentration) appeared to aid flies during the fruit-finding process. As density of fruit or models increased, the probability of flies finding a fruit or model also increased (e.g., 50% of flies found a red fruit model at 1 model/tree while 90% found a red model at 16 models/tree; 4% of flies found a clear model with odor at 1 model/tree while 35% found a clear model with odor at 16 models/tree). Findings reported elsewhere indicate thatR. pomonella flies are able to discover a point source of odor (an odor-bearing tree in a patch of trees) by flying upwind (in the tree patch) in response to intermittent exposure to odor. Findings here indicate that after arrival on a host tree (point source), flies discover individual apparent and abundant host fruit on the basis of vision. If fruit are less apparent or scarce, odor appears to interact with vision during the fruit-finding process.     

Laboratory study of soil acidification and leaching of nutrients from a soil amended with various surface-incorporated acidifying agents

Granular S, finely-ground S, iron sulphate and aluminium sulphate were added at two rates to the surface (0–6 cm) of a soil and acidification and leaching of nutrients were measured over 12 months in a laboratory study. Iron and aluminium sulphate both rapidly lowered soil pH in the top 0–6 cm of the soil. There was little difference in soil pH after 3 and 12 months reaction of these two amendments. In contrast, for granular S and finely-ground S there were clear decreases in soil pH between 3 and 12 months reaction with the soil. Finely-ground S was oxidized in the soil faster than granular S and therefore had a more acidifying effect. The top 0–6 cm of the soil was acidified by all the agents used but the deeper soil was less affected. The only treatments which lowered the pH of the 12–18 cm layer below pH 6 were the high rates of iron and aluminium sulphate. Soil acidification resulted in a decrease in exchangeable Ca, Mg and K, an increase in exchangeable Al and a decrease in effective CEC in the acidified soil layers.At both levels of addition, total ionic strength of percolates from the soil followed the order: aluminium sulphate = iron sulphate > finely gound S > granular S > control and was higher at the higher rate of addition. The pH values of percolates followed the order: control > granular S > finely ground S > iron sulphate = aluminium sulphate and were lower at the higher rate of addition. For the amended soils there was a very close relationship between the pattern and total amounts of SO ₄ ^2- and Ca²⁺ leached.It was concluded that granular S is not an effective acidifying agent since it is oxidized very slowly in the soil and that acidfying agents should be incorporated to the depth that acidification is required.