Cytochrome P-450 Inducers and Inhibitors Interfering with Ecdysone 20-Monooxygenases and Their Activities during Postembryonic Development of Neobellieria bullata Parker

The cytochrome P-450-dependent microsomal and mitochondrial ecdysone 20-monooxygenase systems convert ecdysone into 20-hydroxyecdysone. The microsomal fraction of fat bodies of zero h wandering stage fleshfly larvae (Neobellieria bullata; Diptera: Sarcophagidae) has a high ecdysone 20- monooxygenase activity. The effects of cytochrome P-450 inhibitors were investigated in vitro on microsomal ecdysone 20-monooxygenase. Metyrapone, fenarimol and certain imidazole derivatives (KK-42, KK-110, KK-135 and PIM) are strong inhibitors. The IC₅₀ value of KK-110, which is the strongest inhibitor, is 2 × 10^?7 M. A triazolyl and two cyclopropylamine derivatives have low activity. The activities of different NADPH-cytochrome c (P-450) reductase inhibitors were also assessed; diquat dibromide is a moderate inhibitor of microsomal ecdysone 20-monooxygenase, while paraquat dichloride has no activity. In-vivo experiments with cytochrome P-450 inducers and inhibitors gave the following results: (a) fenarimol, FI-121, precocene-2 caused “permanent” first-instar larvae; (b) barbital, phenobarbital and their sodium salts caused significant delay in larval development; (c) PIM, PTM, metyrapone, KK-42, KK-135, J-2710, RH 5849 and colchicine caused moulting disturbances; (d) J-2710, PIM, PTM, KK-42, KK-135, RH 5849 and colchicine caused lethal spiracle and mandible malformation; (e) KK-110, fenarimol, barbital and phenobarbital caused precocious pupariation.     

Partition of Cd,Cu, Pb and Zn among mineral particles during their sorption in soils

Journal of Soils and Sediments - Heterogeneity of soil mineral particles may lead to the misinterpretation of bulk sorption data on their role in metal sorption, which may be resolved through the...     

Subsurface accumulation of CaCO_3 and Cl~- from groundwater under black locust and poplar plantations

When conditions are similar,more water evaporates from forest plantations than herbaceous vegetation,thereby affecting hydrological fluxes and ion transport in the soil.The vertical distribution of CaCO3 and Cl^-ions shifts due to afforestation.The effect of groundwater depth and clay content were studied in the Great Hungarian Plain where forest area has been increasing for decades by analyzing soil and groundwater samples from stands of black locust(Robinia pseudoacacia,11 plots)and poplar(Populus spp.,11 plots).All study sites contained one herbaceous(control)and one or more forested plots.CaCO3 and Cl^-ions accumulated in the soil profile in greater quantities under tree cover than in the controls.The scale of this process largely depended on the species and on soil and ion properties.Under black locust,Cl^-accumulated between 1.3 and 6.3 m,with a maximum difference of 0.3 pCl unit(pCl is Cl^-activity,the negative of the logarithm to base 10 of the concentration of the chloride ion,determined using an ion-selective electrode,it is a dimensionless quantity.),while the difference in CaCO3 accumulation was at most 3.5%in some layers,compared to control plots.This result may be explained by the difference in the mobility of Ca+and Cl^-ions.Different mechanisms were noticeable under poplar plantations due to their higher water uptake:Cl-accumulation was detected below 0.9 m to the groundwater with a maximum difference of 0.5 pCl units,while CaCO3 accumulation was continuous at depths of 2.3–6.8 m with a maximum difference of 8.4%,compared to the controls.With increasing clay content,there was a discernible effect on CaCO3 and Cl-accumulation under black locust,but not observed under poplars.These differences were explained by the differences in water uptake mechanisms and root patterns of the two species and the different mobility of Ca2^+and Cl-ions.     

Metabolism of fatty acids in fish: III. Combined effect of environmental temperature and diet on formation and deposition of fatty acids in the carp,Cyprinus carpio Linnaeus 1758

Formation and deposition of fatty acids in carp maintained on diets differing in total fat as well as linolenic acid content was investigated by following the incorporation of (1-¹⁴C)-acetate into liver total- and phospholipid fatty acids at two extreme temperatures (5° and 25°C). Excess dietary linolenic acid was deposited in triglycerides but not in phospholipids. The formation and level of phospholipid docosahexenoic acid was, however, dependent on the amount of linolenic acid in the diet. Despite the vast quantities of ingested linolenic acid, the carp on diets containing sufficient essential fatty acid maintained similar membrane fluidities as judged from the ratio of saturated to unsaturated fatty acids. Decrease of the environmental temperature brought about a reduction in the rate of formation of palmitic acid and an increase in the rate of formation of docosahexenoic acid in carp receiving sufficient essential fatty acid. Consequently, the level of palmitic acid decreased and that of docosahexenoic acid increased in the liver phospholipids in carp and a number of other fish species. Essential fatty acid deficient carp were unable to increase the rate of production of long chain polyunsaturated fatty acids upon exposure to cold. The results are discussed from the point of view of adaptation of membrane fluidity to the temperature by fish, and the importance of docosahexenoic acid in this process is emphasized.     

Species hybrids in the genus <Emphasis Type="Italic">Phytophthora</Emphasis> with emphasis on the alder pathogen <Emphasis Type="Italic">Phytophthora alni</Emphasis>: a review

This review provides a summary of recent examples of interspecific hybridisation within the oomycetous genus Phytophthora. Species hybrids either created in the laboratory or evolved in natural environments are discussed in association with evolutionary issues and possible threats they may pose to agriculture, horticulture and forestry. It is suggested that sustainable control of such hybrids will depend on the better understanding of temporal and spatial aspects of genetic mechanisms and environmental factors that lead to the hybridisation process and thus the genetic diversity in Phytophthora populations.     

Effects of medetomidine-midazolam-fentanyl IV bolus injections and its reversal by specific antagonists on cardiovascular function in rabbits

The objective of this study was to investigate the short-term cardiovascular effects of intravenous (IV) medetomidine-midazolam-fentanyl (MMF) injections in the rabbit using vascular ultrasonography and echocardiography.Anesthesia with MMF was induced intramuscularly (IM) in 8 female New Zealand White rabbits before 3 defined bolus injections of MMF were given IV. Before and for 10 min after each MMF injection the following vascular variables [at the left common carotid artery (ACC) after the first injection and at the abdominal aorta (AA) after the second injection]: vessel diameter (D), peak systolic, minimum diastolic, end-diastolic and average blood flow velocities (psBFV, mdBFV, edBFV, Vave), average volumetric flow (VFave), resistance index (RI) and pulsatility index (PI) and other clinical variables: mean arterial pressure (MAP), heart rate (HR), peripheral arterial oxygen saturation and end-tidal CO₂ were recorded. Echocardiography was used after the third injection to investigate changes in cardiac parameters. Additionally, hemodynamic effects were observed at the ACC after complete subcutaneous antagonism of anesthesia by atipamezole-flumazenil-naloxone (AFN) until recovery of the animals.Medetomidine-midazolam-fentanyl IV caused a significant decrease of blood flow velocity in both investigated vessels which was associated with a significant decrease of HR and cardiac performance indicated by the decrease of FS and average volumetric blood flow. Mean arterial pressure significantly increased after each MMF injection; whereas, it significantly decreased after AFN injection. Therefore, MMF and AFN should be carefully used in rabbits and may not be suitable in patients with ventricular dysfunction.     

Effects of cultivar and processing method on the contents of catechins and procyanidins in grape juice

The aim of the presented work was to study the effect of pressing method, pasteurization, cultivar, and vintage on the content of (+)-catechin, (-)-epicatechin, and nine procyanidins in grape juice. The results showed that the concentration of these flavan-3-ols in the juice was influenced, in decreasing order of importance, by pressing method, cultivar, pasteurization, and vintage. Cold pressing without maceration was the least and hot pressing after maceration at 60 degrees C for 60 min the most effective method for extracting the flavan-3-ols. Pasteurization increased the concentration of catechins in cold-pressed juices, but it decreased concentrations in hot-pressed juices. The concentration of most procyanidins was increased by pasteurization. Among the white cultivars, Seyval and Niagara were highest in procyanidins and Elvira and Chardonnay were highest in catechins. Vincent, Foch, and Baco were the red cultivars highest in catechins, and Vincent also had the highest content of procyanidins.     

Assemblage level monitoring of stream fishes: The relative efficiency of single-pass vs. double-pass electrofishing

The relative efficiency of single-pass electrofishing of longer stream sections vs. double-pass electrofishing of shorter reaches was evaluated in small (<5 m wide) wadable lowland streams in the Lake Balaton basin, Hungary. Two hundred meters long stream sections at 8 sites were divided into ten 20 m long sampling units each. These units were used to estimate the representativeness of species richness, species composition and relative abundance data at each level of sampling effort (single vs. double-pass, and number of sampling units pooled) using rarefaction and similarity-based approaches. Assemblage variables showed strong response to the length of the stream sampled (number of sampling units pooled). However, no differences were found between the single- and double-pass methods at any level of sample size for any assemblage variable. Estimates of species richness and species occurrence distributions required more sampling effort than estimates of species relative abundances, using any evaluation method. If a proxy estimate of sample representativeness cannot be obtained in the field, a minimum sampling of single-pass electrofishing of 100 m long sections may be necessary even in small wadable streams with low level of habitat and assemblage diversity to get a relatively unbiased picture on assemblage characteristics.     

CT measures of osseous cervicothoracic intervertebral foramina are repeatable and associated with CT measures of adjacent articular processes in horses

Narrowing of the equine cervicothoracic intervertebral foramina (IF) has the potential to cause forelimb lameness and/or neck pain although limited information is available on CT of the IF. The aims of this retrospective, analytical study were to describe a protocol for quantifying CT cervicothoracic IF size; evaluate the repeatability of IF size measures; test associations between IF size and adjacent articular process (AP) size, ventral extent, and anatomic location; and determine the proportion of IF with narrowing. Computed tomographic images were acquired in 20 Warmblood horses that presented with forelimb lameness and/or neck pain. All IF between C5 and T2 (n = 160) were evaluated. IF cross-sectional area (CSA), APCSA, and AP ventral extent were measured. The repeatability of IFCSA measurement was calculated. Possible associations between IFCSA and: APCSA, ventral extent, side, or location were assessed. IF narrowing was defined as more than 50% of reduction in IF height when compared with its widest part(s). The repeatability of IFCSA measurement was excellent. There was a significant association between IFCSA and: APCSA (P < 0.001; R² = 0.859; slope = −0.106), ventral extent (P = 0.022; R² = 0.161; slope = −0.0617), and location (P < 0.001; higher values between C7 and T2). The association between IFCSA and ventral extent was small. Narrowing was identified in 61 (38.1%) IF. Maximum degree of narrowing was most common at the cranial (26.3%) and middle (68.8%) third of the IF. Narrowing was not identified at T1-T2. In conclusion, CT cervicothoracic IF size can be measured with excellent repeatability, and associations were found between IF size and: AP size, ventral extent, and location.