Carotenoids in diets for salmonids: I. Pigmentation of rainbow trout with the individual optical isomers of astaxanthin in comparison with canthaxanthin

Visual and chemical determinations revealed that the individual optical isomers of astaxanthin were more efficacious than canthaxanthin in pigmenting the flesh of rainbow trout (Salmo gairdneri, Richardson). The visual assessment of the astaxanthin pigmentation by means of a colour scale correlated well with the chemical determination. The same utilization was found for all three astaxanthin isomers, (3S, 3′S)-, (3R, 3′S)-, (3R, 3′R)-astaxanthin and a 1 : 2 : 1 mixture of the three isomers.No epimerization took place at the chiral centres of C-3 and C-3′ in astaxanthin. Astaxanthin and canthaxanthin were not interconverted. No metabolites were detected in the flesh.     

Activity concentrations of natural radionuclides and 137Cs in soils of coniferous forest sites in West Anatolia

The surveys of natural gamma-emitting radionuclides and ¹³⁷Cs in surface soils of coniferous forest sites in and around Izmir were conducted during 2003?C2004. The soil samples were collected from three different depths of 15 forest sites, particularly local wild edible mushrooms areas. The average activity concentrations and ranges of the natural radionuclides in the soils were as follows: 30 (14?C51) Bq kg^?1 of ²²⁶Ra; 40 (17?C79) Bq kg^?1 of ²³²Th; and 581 (308?C879) Bq kg^?1 of ⁴⁰K. Moreover, the values of ¹³⁷Cs activity concentrations averaged over the depth sections varied from 20 to 82 Bq kg^?1 with a mean value of 52 Bq kg^?1. Accordingly, the levels of the studied natural radionuclides in the forest soils were within the range specified by UNSCEAR (2000) report for regular soils as well as the agricultural soils from the West Anatolia, while the measured activity levels of ¹³⁷Cs in the forest soils were still high in contrast to agricultural soils after 16 years from the deposition of Chernobyl fallout.     

Light-mediated influence of three understorey species (Calluna vulgaris, Pteridium aquilinum, Molinia caerulea) on the growth of Pinus sylvestris seedlings

Depending on its developmental and morphological characteristics, shrubby or herbaceous understorey vegetation interacts differently with tree seedlings during the regeneration process. In acidic temperate forests, three common understorey plant species??Calluna vulgaris (L.) Hull, Pteridium aquilinum (L.) Kuhn in Kersten, Molinia caerulea (L.) Moench??are known to rapidly colonize forest gaps. Therefore, they often develop at the expense of light-demanding Scots pine (Pinus sylvestris L.) seedlings. An experiment was set up in a nursery in central France to mimic early competition occurring in a newly created gap between Scots pine seedlings and these three common understorey species (young forest-harvested individuals planted at 5 densities from 0 to 57 plants m^?2). Pine seedling survival and growth (height, diameter, shoot and root biomass) and a functional trait (leaf mass on an area basis, LMA) were measured for 2 years, and cross-analysed against plant density, plant cover and available light. When understorey plant density increased, pine seedling diameter growth and biomass were negatively affected by all three plant species; height growth only slowed beneath Pteridium. These negative effects were closely linked to competition for light beneath Pteridium and Molinia. The application of the Beer?CLambert law gave an extinction coefficient k that was high for Pteridium, intermediate for Molinia and much lower for Calluna. LMA was confirmed as an effective foliar trait to reflect the degree of stress undergone by pine seedlings.     

Tree Injection in the Management of Horse-Chestnut Leaf Miner. Cameraria ohridella (Lepidoptera: Gracillariidae)

Insect and disease problems often occur suddenly, and frequently represent a crisis that demands immediate attention. There are some problems with tree health care because application of sprays to shade trees in urban areas requires specialized, expensive equipment. Microinjection is a type of trunk injection where small amounts of therapeutic chemicals are introduced directly into a tree without any contact with the environment. We applied microinjection technology by using VIVID^®II (Tree Tech Microinjection Systems, Morriston, FL, USA) insecticide to solve the problem with horse-chestnut leaf miner (Cameraria ohridella Deschka et Dimic) on horse chestnut tree (Aesculus hippocastanum L.) in urban greenery in Slovakia. In 2006 were treated 230 host trees in 12 localities, 337 trees in 15 localities were treated in 2007. Mean efficiency of control measures was above 95%. The presence of insecticide residues were analyzed in pollen. 0.145 mg/kg of residues was detected in pollen one day after treatment. It decreased rapidly 8 days after treatment and 16 days after treatment was not detectable. In spite of these results the treatment after blossom is recommended.     

Wirkung verschiedener Fungizide auf den Befall der D��rrfleckenkrankheit (Alternaria spp.) sowie auf den Ertrag der Kartoffel

Potato early blight caused by Alternaria solani and Alternaria alternata is a major disease of potatoes and other Solanaceae. By now, Alternaria species have established themselves as destructive pathogens. Due to considerable yield losses early blight is getting a serious problem in many German potato growing areas. Up to now, the management of this disease is achieved mainly through protective fungicide applications. By this, fungicides with different mode of actions have a considerable influence on the course of disease progress. For this, field trials were carried out in 2007 and 2008 and the efficacy of various active ingredients was determined. Marked differences were observed in the control of early blight disease due to the effectiveness of applied active ingredients. The application of potent fungicides, which are highly efficient, resulted in prolonged photosynthesis. As a result of this potato yield increased significantly. Our investigation show, that disease control can be better achieved with strobilurines like Azoxystrobin or Boscalid + Pyraclostrobin than with Mancozeb, Chlorthalonil or Fenamidon.     

Two promoter rearrangements in a drug efflux transporter gene are responsible for the appearance and spread of multidrug resistance phenotype MDR2 in Botrytis cinerea isolates in French and German vineyards

In French and German vineyards, Botrytis cinerea isolates with multiple fungicide resistance phenotypes have been observed with increasing frequencies. Multidrug resistance (MDR) results from mutations that lead to constitutive overexpression of genes encoding drug efflux transporters. In MDR2 and MDR3 strains, overexpression of the major facilitator superfamily transporter gene mfsM2 has been found to result from a rearrangement in the mfsM2 promoter (type A), caused by insertion of a retroelement (RE)-derived sequence. Here, we report the discovery of another, similar RE-induced rearrangement of the mfsM2 promoter (type B) in a subpopulation of French MDR2 isolates. MDR2 isolates harboring either type A or type B mutations in mfsM2 show the same resistance phenotypes and similar levels of mfsM2 overexpression. RE sequences similar to those in mfsM2 were found in low copy numbers in other but not all B. cinerea strains analyzed, including non-MDR2 strains. Population genetic analyses support the hypothesis that the two rearrangement mutations have only occurred once, and are responsible for the appearance and subsequent spread of all known MDR2 and MDR3 strains in French and German wine-growing regions.     

Self-inhibition of spore germination via reactive oxygen in the fungus Cladosporium cucumerinum, causal agent of cucurbit scab

Cladosporium cucumerinum spore germination in vitro depended on spore suspension density. Different fungal isolates displayed germination maxima at different spore concentrations. For one isolate, the maximum was observed at the same spore density at both 18 and 25°C, although germination percentage increased slightly at the higher temperature. Diffusates originating in other spore suspensions of the same isolate reduced germination percentage of spores taken at optimal concentration. The least effect occurred in diffusate taken from spores kept at their optimal concentration. Self-suppression of spore germination at unfavourable concentrations was diminished more or less by antioxidants (superoxide dismutase, catalase, mannitol or formate). The same compounds, added to spore diffusates, reduced their fungitoxicities. All diffusates generated superoxide radical (assayed by adrenalin oxidation sensitive to superoxide dismutase). This activity correlated positively with diffusate toxicity. Leaf inoculation of the susceptible cucumber cultivar at 18°C with spore suspensions at extreme densities, at which they germinated poorly in vitro, led to less disease severity then that at optimal density. In contrast, no disease symptoms appeared at 25°C. It is suggested that spores germinating at their extreme concentrations produced reactive oxygen species, suppressing the pathogen; this effect could reduce disease development at low temperatures. At high temperatures, however, this mechanism seems not to work, suggesting that plant infection may be reduced by other disease inhibiting factors.     

Transport of phosphorus in leaf veins of Vicia faba L.

The plant nutrient phosphorus (P) is spread throughout the plant within the transpiration stream after uptake in the form of phosphate via the roots. Short‐term distribution is therefore strongly dependent on transpiration rather than on sinks, so that P mainly enters adult leaves. The objective of this work was to investigate the transport of phosphate in leaf veins and its distribution within the leaf. Experiments were performed with broad bean (Vicia faba L. var. Scirocco) using radioactively labeled phosphate. In a relatively new approach, the tracer was monitored by a sensitive imaging plate using Fujifilm's Bioimaging Analyzer System. Radioactive label could be monitored in fresh leaves (without fixing) using exposure times of only 5–20 min. For this reason, the method offered the possibility to obtain several subsequent autoradiographic images of the same sample after different feeding times. Phosphate tracer quickly reached small veins, which were then more intensely labeled than the tissue between them. Within the first 15 min, intercostal fields were only slightly stained. After application of phosphate tracer onto the leaf blade, export from the leaf was pronounced and started within 30 min. Phosphorus is effectively redistributed from adult leaves to sinks such as the terminal bud or growing root tips. Using the imaging method, an impression of the high velocity and effectiveness of this process was obtained. The results furthermore imply that leaf veins may be one of the most important locations where exchange between xylem and phloem transport takes place, although exchange between xylem and phloem was also observed in the shoot axis and in the petioles.