Distribution and induction of cytochrome P450 1A1 in the rainbow trout brain

Cytochrome P450 (CYP) 1A1 participates in the activation as well as detoxification of environmental pollutants such as aromatic hydrocarbons. This CYP form is also efficiently induced by aromatic hydrocarbons. The presence of CYP 1A1 in the brain might thus be of physiological and toxicological importance. In the present investigation on rainbow trout, the distribution of 7-ethoxyresorufin-O-deethylase (EROD) activity, a cytochrome CYP 1A1 catalyzed reaction, was measured in whole tissue homogenates from brain parts. In control fish, a relatively high activity was found in the rainbow trout olfactory bulb compared to the other brain parts. Although an EROD induction (3 to 7-fold) by β-naphthoflavone (BNF) was recorded in all brain parts from the rainbow trout, the highest induced activity was measured in the olfactory bulbs. To ascertain the distribution of EROD activity in cells, whole brain tissue was subfractionated by differential centrifugation. The fractionation scheme separated mitochondria (P2 fraction) and microsomes (P3 fraction) as determined by marker enzymes and electron microscopy. In control rainbow trout, a low EROD activity could be measured in the P2 fraction. BNF induced the EROD activity in both P2 and P3 fractions. Western blotting showed the induction by BNF of a protein band in the P2 and P3 fractions with a molecular mass around 58,000 when highly specific anti-cod CYP 1A1 antibodies were used. ELISA measurements confirmed the induction of CYP 1A1 protein in the rainbow trout brain subcellular fractions.     

Recent findings on certain bioactive components in whole grain wheat and rye

Whole grain wheat and rye are important sources of many bioactive compounds and contribute significantly to the total intake of cereals in many countries. Alkylresorcinols, benzoxazinoids, lignans, phenolic acids, phytosterols and tocols are common bioactive compounds present in these cereals. In this review, we report recent findings (mainly from 2010 onwards) regarding their content, composition, effects of food processing and their uptake, elimination and bioactivities with implications for health.     

Breed, sex and age distribution in dogs with chronic liver disease: a demographic study

Breed, sex and age distribution were studied in dogs with histopathologically diagnosed chronic (active or progressive) hepatitis and liver cirrhosis in Sweden. The study was based on clinical and histopathological records obtained during three years from a histopathological laboratory and during six years from an animal hospital. Some breeds were significantly (P<0–001) over-represented: American and English cocker spaniels, labrador retrievers and West Highland white terriers. In both spaniel breeds the males were most frequent whereas in the labrador retriever, the females were over represented. In the West Highland white terrier there was no sex difference. The average age at presentation was approximately five years in spaniels and West Highland white terriers and seven years in labrador retrievers. The high incidence of chronic liver disease and liver cirrhosis in certain breeds indicate that hereditary factors may be of importance in the development of chronic hepatitis and liver cirrhosis.     

Influence of wetland liming on water chemistry of acidified mountain streams in Lofsdalen,Central Sweden

Acidic precipitation has caused damage to the populations of fish and invertebrates in numerous streams in the southern part of the Swedish mountain range. In the middle of the 70's, the pH of precipitation decreased and has since then frequently been lower than 4.5. Many of the streamwaters were well buffered during most time of the year, but during periods with high discharge, the buffering capacity was completely exhausted, pH frequently decreased to around 4.5 and very high levels of Fe, Mn and Al occurred. In general, base cations (BC) and organic anions decreased during periods of high flow, while SO₄ increased or was relatively independent of flow. On an average, the ratio SO₄/BC was negatively correlated to pH, while organic anions/BC showed a weaker correlation to pH. In order to investigate if wetland liming could be used as a remedial measure in such areas, lime treatments were started in 1983 in the Lofsdalen area, province of Härjedalen. The liming stabilized the alkalinity and pH of the streams at circum-neutral levels, and reduced the leaching of Fe, Mn, and Al. The average levels of these elements decreased and the seasonal fluctuation decreased considerably.     

Irrigation of Landfill Leachates in Energy Forests — A Technique to Recover Nutrients from Municipal Solid Wastes

From an ecological point of view it is important to close nutrient cycles by recirculating mineral nutrients from the urban society back to agriculture and forestry, and thereby obtaining a sustainable resource utilisation. A part of this cycle is illustrated by irrigation of bioreactor landfill leachates on short rotation forests. This paper presents a budget for nutrients and heavy metals, beginning with the leachates and ending with the harvested tree fraction. The hypotheses were: The applied minerals deliver nutrients to the trees. The nutrient content in the accumulating biomass corresponds to the amount of mineral nutrients applied. The concentrations of heavy metals in the trees will remain low. The uptake of elements in birch was for P 35%, Ca 1. 2%, Cd 64%, Cu 10%, Mn 19%, Ni 0. 11%, and for Zn 26% of the supplied amounts. It was concluded that nutrients, with some exceptions, are supplied in sufficient amounts from the irrigated leachates to achieve optimal biomass growth, that the amounts of ions immobilised by the plants were significantly lower compared to the applied amounts, and that the concentrations of heavy metals are not increasing in the trees after irrigation. The overall conclusion is that a leachate irrigation system is efficient if the available vegetated land area is large enough for effective nutrient uptake, but the nutrient ratio may need to be balanced to meet the needs of the plants.     

A glycyl radical site in the crystal structure of a class III ribonucleotide reductase

Ribonucleotide reductases catalyze the reduction of ribonucleotides to deoxyribonucleotides. Three classes have been identified, all using free-radical chemistry but based on different cofactors. Classes I and II have been shown to be evolutionarily related, whereas the origin of anaerobic class III has remained elusive. The structure of a class III enzyme suggests a common origin for the three classes but shows differences in the active site that can be understood on the basis of the radical-initiation system and source of reductive electrons, as well as a unique protein glycyl radical site. A possible evolutionary relationship between early deoxyribonucleotide metabolism and primary anaerobic metabolism is suggested.     

Acetylcholine-synthesizing T cells relay neural signals in a vagus nerve circuit

Neural circuits regulate cytokine production to prevent potentially damaging inflammation. A prototypical vagus nerve circuit, the inflammatory reflex, inhibits tumor necrosis factor-α production in spleen by a mechanism requiring acetylcholine signaling through the α7 nicotinic acetylcholine receptor expressed on cytokine-producing macrophages. Nerve fibers in spleen lack the enzymatic machinery necessary for acetylcholine production; therefore, how does this neural circuit terminate in cholinergic signaling? We identified an acetylcholine-producing, memory phenotype T cell population in mice that is integral to the inflammatory reflex. These acetylcholine-producing T cells are required for inhibition of cytokine production by vagus nerve stimulation. Thus, action potentials originating in the vagus nerve regulate T cells, which in turn produce the neurotransmitter, acetylcholine, required to control innate immune responses.     

Delineating the drivers of waning wildlife habitat: The predominance of cotton farming on the fringe of protected areas in the Mid-Zambezi Valley, Zimbabwe

Zimbabwe’s Mid-Zambezi Valley is of global importance for the emblematic mega-fauna of Africa. Over the past 30 years rapid land use change in this area has substantially reduced wildlife habitat. Tsetse control operations are often blamed for this. In this study, we quantify this change for the Dande Communal Area, Mbire District, of the Mid-Zambezi Valley and analyse the contribution of three major potential drivers: (1) increase in human population; (2) increase in cattle population (and the expansion of associated plough-based agriculture), and; (3) expansion of cotton farming. Although direct effects of land use change on wildlife densities could not be proven, our study suggests that the consequences for elephant and buffalo numbers are negative. All three of the above drivers have contributed to the observed land use change. However, we found farmland to have expanded faster than the human population, and to have followed a similar rate of expansion in cattle sparse, tsetse infested areas as in tsetse free areas where cattle-drawn plough agriculture dominates. This implies the existence of a paramount driver, which we demonstrate to be cotton farming. Contrary to common belief, we argue that tsetse control was not the major trigger behind the dramatic land use change observed, but merely alleviated a constraint to cattle accumulation. We argue that without the presence of a cash crop (cotton), land use change would have been neither as extensive nor as rapid as has been observed. Therefore, conservation agencies should be as concerned by the way people farm as they are by population increase. Conserving biodiversity without jeopardising agricultural production will require the development of innovative technological and institutional options in association with policy and market interventions.     

The influence of water stress and air velocity on growth of Impatiens walleriana and Petunia × hybrid

Impatiens walleriana ‘DeZire’ and Petunia × hybrid ‘Tidal Wave’ were subjected to a combination of water stress and exposure to wind to evaluate the potential application of these treatments as an alternative to chemical growth retardation. Air velocities evaluated were 0.1, 0.2, 0.4, 0.8, 1.5, and 4.5 m s⁻¹ and irrigation treatments were either control or 45% water stress based on irrigation occurring when the weight of the plant (plant, pot and peat) was reduced by 25% (control) or 45% (water stress) of the initial weight. The experiment was repeated twice; once in spring and once in summer.