Oxidative stress in the pathogenesis of canine zinc‐responsive dermatosis

Zinc deficiency causes skin diseases both in humans and in animals. The underlying pathogenic mechanisms remain unclear, but a growing body of evidence indicates a role for zinc in skin protection against free radical‐induced oxidative damage. The immunohistochemical expression of heat shock proteins (HSPs; Hsp27, Hsp72, Hsp73 and Hsp90), Cu/Zn superoxide dismutase (SOD), metallothionein (MT), Ki‐67 antigen and active caspase‐3 were evaluated in normal canine skin and in samples from eight dogs with zinc‐responsive dermatosis. All investigated HSPs showed intense cytoplasmic immunostaining in the affected epidermis. Focal nuclear positivity of Hsp72 was also detected in keratinocytes. Although Cu/Zn SOD expression was similar to that observed in normal skin, MT immunoreactivity occurred in both the cytoplasm and the nucleus of basal cells in normal skin but was absent from the affected epidermis. Caspase‐3 activation was also absent in the involved epidermis, which revealed a high Ki‐67 index (a 3.5‐ to 9‐fold increase compared with normal skin). These results support the hypothesis that cellular response to stress, particularly oxidative stress, is involved in the pathogenesis of skin lesions in canine zinc‐responsive dermatosis. The lack of MT immunoreactivity in the affected epidermis may be indicative of low zinc levels, thus resulting in vulnerability to oxidative damage. In contrast, high expression levels of HSPs in skin during zinc deficiency may confer protection against a variety of dangerous stimuli, contributing to inhibition of apoptosis and to cell cycle regulation of proliferating keratinocytes.     

Lead uptake,distribution, and remobilization in cucumber

Mobility and distribution of lead (Pb) were investigated in cucumber (Cucumis sativus L.) grown in solution culture. Based on the observation that Pb uptake is influenced by the chemical form of iron (Fe) (complexed or ionic) in the solution, Fe distribution was also determined. Iron concentration was even in the stem (separated to internodes) and petioles but slightly increased at the shoot tip while Pb concentration decreased upwards. In the leaves Fe concentration decreased upwards (whereas in the control it increased a little at the youngest leaves) while Pb concentration increased to the largest leaves then decreased towards the shoot tip. It is suggested that the distribution of Pb in cucumber is passive process and it accumulates in the apoplast while Fe distribution is determined by the requirements of synthetic processes in young or photosynthesizing tissues. Lead probably lowers Fe transport into the symplast in the leaves causing slight chlorosis at the youngest leaves. In the plants that were loaded with Pb, decapitated and rooted again in Pb‐free culture solution we found no significant remobilization of Pb which supports that Pb binds strongly to the binding sites in the apoplast or is detoxified in an immobile form.     

Residual Nitrogen Effects in Organically Cultivated Beetroot Following a Harvested/Green Manured Grass-Clover Ley

ABSTRACT

The residual nitrogen (N) effect on beetroot following harvested grass-clover (H-ley) or corresponding twice-cut green manure (GM-ley) was compared with a barley control. The residual N at beetroot harvest, calculated as N in beetroot crop and mineral N in the 0–90 cm soil layer, was 83 kg ha^?1 for the GM-ley when barley was set to zero. The effect of GM-ley exceeded that of 3H-ley (3 harvests) by 74 kg N ha^?1 and 2H-ley (2 harvests) by 42 kg N ha^?1. Prediction of residual effects was studied using a model with a humification coefficient (hc) of 0.35 and another with different hc values for different plant materials. The former gave the best fit to observed data in regression analysis. The latter gave the best fit to observed data in absolute values. The residual N effect of GM biomass from summer cuttings corresponded to 40–70% of the potential effect.     

Quantification of seasonal sediment and phosphorus transport dynamics in an agricultural watershed using radiometric fingerprinting techniques

Purpose

Phosphorus (P) is a limiting nutrient for most US Midwestern aquatic systems and, therefore, increases of P, through point or non-point sources (NPS) of pollution such as agriculture, causes eutrophication. Identifying specific NPS contributions (e.g., upland vs. stream channels) for sediments and P is difficult due to the distributed nature of the pollution. Therefore, studies which link the spatial and temporal aspects of sediment and P transport in these systems can help better characterize the extent of NPS pollution.

Materials and methods

Our study used fingerprinting techniques to determine sources of sediments in an agricultural watershed (the North Fork of the Pheasant Branch watershed; 12.4 km² area) in Wisconsin, USA, during the spring, summer, and fall seasons of 2009. The primary sources considered were uplands (cultivated fields), stream bank, and streambed. The model used fallout radionuclides, ¹³⁷Cs, and ²¹⁰Pb_xs, along with total P to determine primary sediment sources. A shorter-lived fallout radioisotope, ⁷Be, was used to determine the sediment age and percent new sediments in streambed and suspended sediment samples (via the ⁷Be/²¹⁰Pb_xs ratio).

Results and discussion

Upland areas were the primary source of suspended sediments in the stream channels followed by stream banks. The sediment age and percent new sediment for the streambed and suspended sediments showed that the channel contained and transported newer (or more recently tagged with ⁷Be) sediments in the spring season (9–131 days sediment age), while relatively old sediments (165–318 days) were moving through the channel system during the fall season.

Conclusions

Upland areas are the major contributors to in-stream suspended sediments in this watershed. Sediment resuspension in stream channels could play an important role during the later part of the year. Best management practices should be targeted in the upland areas to reduce the export of sediments and sediment-bound P from agricultural watersheds.     

Changes in the content of L-ascorbic acid,glucose, fructose,sucrose and total glycoalkaloids in potatoes (cv. Bintje) stored at 7, 16 and 28°C

Summary We investigated the changes in the content of L-ascorbic acid (L-AA), glucose, fructose, surose and total glycoalkaloids (TGA) during storage of potatoes, cv. Bintje, for 12 weeks at 7,16 and 28°C. The initial amount of L-AA was 8.2 mg/100g fresh weight; after 12 weeks' storage at 7°C it had decreased, while at 16 and 28°C it had increased. The sugar content went up most in potatoes stored at 28°C, but remained below the level at which potatoes taste sweet. The sugar content rose slightly at 16°C, while it decreased in tubers stored at 7°C. The initial TGA content, in equivalent amounts of α-solanine, was 3.6 mg/100 g fresh weight; after 12 weeks' storage it had decreased slightly at all three storage temperatures.     

Microbial dynamics after adding bovine manure effluent together with a nitrification inhibitor (3,4 DMPP) in a microcosm experiment

The application of animal manure effluents in agriculture in combination with nitrification inhibitors should be beneficial for nutrient recycling, soil quality, plant productivity, and greenhouse gas emission and offer economic advantages to make them an alternative to conventional fertilizers. The present study aims to estimate the effects of the addition of bovine manure effluent alone or together with a nitrification inhibitor (3,4-dymethylpyrazol-phosphate (3,4 DMPP)) on the microbial community dynamics in a Mediterranean soil in an incubation experiment over 28 days. The application of the bovine manure effluent increased respiration, microbial biomass carbon, fungal and bacterial growth, and enzyme activities and changed the microbial community structure evaluated by the phospholipid fatty acid pattern. Adding the bovine manure effluent together with the nitrification inhibitor, although partly negating the positive effect of the effluent on soil microbial activity, still resulted in higher or similar growth and activity as in the control. Our results indicate that the addition of the nitrification inhibitor 3,4 DMPP together with a bovine manure effluent could be a promising solution to control the animal manure effluent application effects on soil microbiological properties and microbial dynamics, as well as counteracting direct inhibiting effects of 3,4 DMPP on the soil heterotrophic community.